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Toyoaki Murohara

murohara@med.nagoya-u.ac.jp

Journal articles

2008
 
PMID 
Toru Aoyama, Hideki Ishii, Takanobu Toriyama, Hiroshi Takahashi, Hirotake Kasuga, Ryuichiro Murakami, Tetsuya Amano, Tadayuki Uetani, Yoshinari Yasuda, Yukio Yuzawa, Shoichi Maruyama, Seiichi Matsuo, Tatsuaki Matsubara, Toyoaki Murohara (2008)  Sirolimus-Eluting Stents vs Bare Metal Stents for Coronary Intervention in Japanese Patients With Renal Failure on Hemodialysis.   Circ J 72: 1. 56-60 Jan  
Abstract: Background Accelerated atherosclerosis is a major risk for long-term survivors receiving hemodialysis (HD), with coronary events being the leading cause of mortality. Methods and Results A total of 88 consecutive patients on HD (121 lesions) who underwent percutaneous coronary intervention (PCI) with sirolimus-eluting stents (SES) were compared with 78 patients on HD (95 lesions) who received bare metal stents (BMS) in the preceding 1 year. The primary endpoint was angiographic restenosis defined as >/=50% diameter stenosis at 6-8 months follow-up after PCI. The angiographic restenosis rate at follow-up was 22.2% in the SES group and 24.4% in the BMS group. No difference was detected in the restenosis rate between the 2 groups (p=0.73). When including both HD and non-HD patients, the independent predictors for restenosis after SES implantation were treatment with HD (hazard ratio (HR) 3.12; 95% confidence interval (CI) 1.23-7.95; p=0.016), incidence of hyperlipidemia (HR 3.93; 95%CI 1.12-13.7; p=0.032), coronary calcification (HR 2.78; 95%CI 1.12-6.91; p=0.027), and implantation of multi-stents (HR 4.14; 95%CI 1.70-10.1; p=0.0017). Conclusions Even if treated with SES, patients with end-stage renal failure on HD are at high risk of restenosis after PCI. (Circ J 2008; 72: 56 - 60).
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Mitsuhisa Koga, Hisashi Kai, Kimiyasu Egami, Toyoaki Murohara, Ayami Ikeda, Suguru Yasuoka, Kensuke Egashira, Toyojiro Matsuishi, Mamiko Kai, Yasufumi Kataoka, Michihiko Kuwano, Tsutomu Imaizumi (2008)  Mutant MCP-1 therapy inhibits tumor angiogenesis and growth of malignant melanoma in mice.   Biochem Biophys Res Commun 365: 2. 279-284 Jan  
Abstract: We investigated whether blocking of monocyte chemoattractant-1 (MCP-1) function would inhibit recruitment of tumor-associated macrophages (TAMs) and prevent tumor angiogenesis and tumor growth of human malignant melanoma. B16-F1 melanoma cells were implanted onto the back of C57BL/6 mice (Day 0). At Day 7, a dominant negative MCP-1 mutant (7ND) gene was transfected in the thigh muscle to make overexpressed 7ND protein secreted into systemic circulation. 7ND treatment inhibited TAM recruitment and partially reduced tumor angiogenesis and tumor growth. Also, 7ND treatment attenuated inductions of tumor necrosis factor-alpha (TNFalpha), interleukin-1alpha (IL-1alpha), and vascular endothelial growth factor (VEGF) in the stroma and tumor. Melanoma cells expressed not only MCP-1 but also its receptor CCR2. Accordingly, it was suggested that MCP-1 would enhance tumor angiogenesis and early tumor growth in the early stages by inducing TNFalpha, IL-1alpha, and VEGF through TAM recruitment and probably the direct autocrine/paracrine effects on melanoma cells.
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2007
 
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PMID 
Akiko Noda, Hideo Izawa, Hiroyuki Asano, Seiichi Nakata, Akihiro Hirashiki, Yosuke Murase, Shigeo Iino, Kohzo Nagata, Toyoaki Murohara, Yasuo Koike, Mitsuhiro Yokota (2007)  Beneficial effect of bilevel positive airway pressure on left ventricular function in ambulatory patients with idiopathic dilated cardiomyopathy and central sleep apnea-hypopnea: a preliminary study.   Chest 131: 6. 1694-1701 Jun  
Abstract: BACKGROUND: Sleep-disordered breathing is common in individuals with left ventricular (LV) dysfunction and has been treated with nocturnal positive airway pressure. We investigated whether treatment of central sleep apnea-hypopnea with bilevel positive airway pressure (BPAP) in ambulatory patients with idiopathic dilated cardiomyopathy (IDCM) might improve LV function. METHODS: Fifty-two consecutive patients with IDCM who underwent both cardiac catheterization and standard polysomnography were enrolled in the study; individuals with obstructive sleep apnea syndrome were excluded. Subjects with an apnea-hypopnea index (AHI) >or= 20 episodes per hour were randomized to receive medical therapy either alone (n = 11) or together with BPAP (n = 10). RESULTS: LV end-diastolic pressure, pulmonary capillary wedge pressure, and plasma concentration of brain natriuretic peptide were significantly greater, and LV ejection fraction (LVEF) was significantly lower in patients with an AHI >or= 20/h (n = 21, 40.4%) than in those with an AHI < 20/h (n = 31, 59.6%). LVEF (30.5 +/- 1.6% vs 50.8 +/- 3.5%, p < 0.001) [mean +/- SE] and plasma concentration of brain natriuretic peptide (162.8 +/- 44.5 pg/mL vs 32.7 +/- 17.6 pg/mL, p = 0.02) were significantly increased and decreased, respectively, after treatment with BPAP (daily use, 4.8 +/- 0.3 h) for 3 months, whereas these parameters remained unchanged in the control subjects. CONCLUSIONS: Our findings suggest that treatment of coexisting central sleep apnea-hypopnea with BPAP improves LV function in ambulatory patients with IDCM. BPAP should thus be considered as a nonpharmacologic adjunct to conventional drug therapy in such patients.
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Taro Okada, Takumi Yamada, Yoshimasa Murakami, Naoki Yoshida, Yuuichi Ninomiya, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Teruo Ito, Naoya Tsuboi, Takahisa Kondo, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2007)  Prevalence and severity of left atrial edema detected by electron beam tomography early after pulmonary vein ablation.   J Am Coll Cardiol 49: 13. 1436-1442 Apr  
Abstract: OBJECTIVES: The aim of this study was to investigate the prevalence and severity of left atrial (LA) edema after pulmonary vein (PV) ablation and its effect on the cardiac function. BACKGROUND: Though extensive LA catheter ablation has been demonstrated to be more effective in curing paroxysmal atrial fibrillation (PAF) than segmental ostial pulmonary vein isolation (S-PVI), it might cause life-threatening complications, including congestive heart failure associated with LA edema. METHODS: Fifty patients underwent S-PVI (Group S) and 27 underwent circumferential PV antrum ablation (Group C) for drug-refractory PAF. Enhanced electron beam tomography (EBT) was performed before, 1 or 2 days after, and 1 month after the PV ablation, and transthoracic ultrasound cardiography (UCG) was performed 1 month after the PV ablation in all patients. RESULTS: The EBT assessment revealed LA edema immediately after the PV ablation in 47 Group S patients and all Group C patients. The severity of the LA edema, number of radiofrequency applications, and amount of radiofrequency energy delivered during the PV ablation was significantly greater in Group C than in Group S. One month after the PV ablation, in all patients, the EBT assessment revealed that those edematous changes had disappeared, and the UCG assessment showed no reduction in the cardiac function. CONCLUSIONS: Left atrial edema was observed in a large portion of the patients immediately after the PV ablation, and the severity of the LA edema depended on the extent and amount of the radiofrequency energy delivered in the PV ablation. The LA edema soon disappeared naturally and did not reduce the cardiac function.
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Hideki Ishii, Takanobu Toriyama, Toru Aoyama, Hiroshi Takahashi, Shigeki Yamada, Hirotake Kasuga, Satoshi Ichimiya, Masaaki Kanashiro, Hirotsugu Mitsuhashi, Shoichi Maruyama, Seiichi Matsuo, Keiko Naruse, Tatsuaki Matsubara, Toyoaki Murohara (2007)  Efficacy of oral nicorandil in patients with end-stage renal disease: a retrospective chart review after coronary angioplasty in Japanese patients receiving hemodialysis.   Clin Ther 29: 1. 110-122 Jan  
Abstract: BACKGROUND: Patients receiving hemodialysis for end-stage renal disease (ESRD) are at high risk for death from ischemic heart disease (IHD). Nicorandil, a hybrid compound of adenosine triphosphate-sensitive potassium channel opener and nitric oxide donor, has been reported to improve the clinical prognosis of patients with IHD. OBJECTIVE: This study sought to investigate the efficacy of oral nicorandil in reducing the risks for cardiovascular events (CVEs) and CVE-related death in patients receiving hemodialysis for ESRD after undergoing percutaneous coronary intervention (PCI) for angina pectoris. METHODS: For this retrospective chart review, we used data from telephone interviews and medical charts from 3 hospitals in Japan. Data from patients aged <80 years who were receiving hemodialysis for ESRD and who had undergone successful PCI for angina between January 1999 and December 2004 were included in the analysis. Patients were stratified based on status of nicorandil treatment before PCI, as follows: patients receiving nicorandil 5 mg PO TID (the recommended dosage in Japan) for >1 month before PCI (nicorandil group) or those who did not receive nicorandil (control group). We investigated 6-year follow-up data on the primary end point, defined as CVEs (ie, unplanned hospital admission for worsening anginal status, or CVE-related death). The secondary end point was CVE-related death. After the data were initially analyzed, we performed a propensity-matched analysis to minimize selection bias. RESULTS: Data from 356 patients were included in the study (235 men, 121 women; mean [SD] age, 69 [9] years; mean [SD] weight, 52.3 [9.1] kg; nicorandil group, 198 patients; control group, 158 patients). According to the estimated propensity scores, 107 patients from each group were matched. There were no differences between the 2 groups in the baseline characteristics. On propensity-matched patient analysis, the estimated rates of patients who were CVE-free at 6 years were 33.5% in the nicorandil group and 21.8% in the control group on Kaplan-Meier analysis (hazard ratio [HR] = 0.53; 95% CI, 0.36-0.78; P < 0.002), and the rates of 6-year survival (ie, patients who did not experience CVE-related death) were 92.7% in the nicorandil group and 85.8% in the control group (HR = 0.27; 95% CI, 0.07-0.89; P = 0.047). Cox multivariate analysis found that nico-randil treatment status was an independent predictor of CVEs (HR = 0.40; 95% CI, 0.18-0.91; P = 0.028) and CVE-related death (HR = 0.38; 95% CI, 0.14-0.78; P = 0.030). CONCLUSION: Results obtained in this retrospective study suggest the potential efficacy of nicorandil treatment in improving clinical outcomes in patients with IHD receiving hemodialysis following PCI.
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Tetsuya Amano, Tatsuaki Matsubara, Tadayuki Uetani, Michio Nanki, Nobuyuki Marui, Masataka Kato, Kosuke Arai, Kiminobu Yokoi, Hirohiko Ando, Hideki Ishii, Hideo Izawa, Toyoaki Murohara (2007)  Impact of metabolic syndrome on tissue characteristics of angiographically mild to moderate coronary lesions integrated backscatter intravascular ultrasound study.   J Am Coll Cardiol 49: 11. 1149-1156 Mar  
Abstract: OBJECTIVES: We assessed the impact of metabolic syndrome (MetS) on the tissue characteristics of coronary plaques using integrated backscatter intravascular ultrasound (IB-IVUS). BACKGROUND: Metabolic syndrome is associated with the increasing risk of cardiovascular disease. METHODS: We identified MetS by the definition of the National Cholesterol Education Program in Adult Treatment Panel III criterion. Non-target coronary lesions with mild to moderate stenosis were measured by conventional and IB-IVUS parameters using 40-MHz (motorized pullback 0.5 mm/s) intravascular catheter. A total of 20 IB-IVUS images were recorded at an interval of 0.5 mm for 10 mm length in each plaque. The 3-dimensional analyses were performed using commercially available software. RESULTS: The prevalence of MetS was 61 patients (50%) with 73 lesions (49%) among 122 patients with 148 lesions. Patients with MetS showed a significant increase in percentage lipid area (38 +/- 19% vs. 30 +/- 19%, p = 0.02) and percentage lipid volume (39 +/- 17% vs. 33 +/- 17%, p = 0.03), and they also showed a significant decrease in percentage of fibrous volume (57 +/- 14% vs. 61 +/- 13%, p = 0.03). Multivariate regression analysis after adjustment for potentially confounding risk factors showed that MetS remains correlated independently with the percentage of lipid volume (r = 0.223, p = 0.01). Logistic regression analysis after adjusting for confounding and non-MetS coronary risk factors showed that MetS (odds ratio 4.00, 95% confidence interval 1.33 to 12.0, p = 0.01) is proved to be an independent predictor of the lipid-rich plaque. CONCLUSIONS: Metabolic syndrome is associated with lipid-rich plaques, contributing to the increasing risk of plaque vulnerability.
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Sahoko Ichihara, Yoshiji Yamada, Gaku Ichihara, Tamie Nakajima, Ping Li, Takahisa Kondo, Frank J Gonzalez, Toyoaki Murohara (2007)  A role for the aryl hydrocarbon receptor in regulation of ischemia-induced angiogenesis.   Arterioscler Thromb Vasc Biol 27: 6. 1297-1304 Jun  
Abstract: OBJECTIVE: The aryl hydrocarbon receptor (AHR) is a transcription factor that binds to DNA as a heterodimer with the AHR nuclear translocator (ARNT) after interaction with ligands such as polycyclic and halogenated aromatic hydrocarbons found in tobacco smoke and the environment. We have investigated the interaction between AHR and hypoxia signaling pathways in regulation of angiogenesis with the use of a surgical model of ischemia. METHODS AND RESULTS: Ischemia was induced by femoral artery occlusion in wild-type and AHR-null mice. Ischemia-induced angiogenesis was markedly enhanced in AHR-null mice compared with that in wild-type animals. Ischemia-induced upregulation of the expression of hypoxia-inducible factor-1alpha (HIF-1alpha) and ARNT as well as that of target genes for these transcription factors, such as that for vascular endothelial growth factor (VEGF), were also enhanced in AHR-null mice. Furthermore, the DNA binding activity of the HIF-1alpha-ARNT complex as well as the association of HIF-1alpha and ARNT with the VEGF gene promoter were increased by ischemia to a greater extent in AHR-null mice than in wild-type animals. CONCLUSIONS: Ablation of AHR resulted in enhancement of ischemia-induced angiogenesis. This effect was likely attributable in part to the associated enhancement of ischemia-induced VEGF expression, which in turn may be caused by an increased abundance and activity of the HIF-1alpha-ARNT heterodimer.
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Hirotsugu Mitsuhashi, Hiroshi Yatsuya, Koji Tamakoshi, Kunihiro Matsushita, Rei Otsuka, Keiko Wada, Kaichiro Sugiura, Seiko Takefuji, Yo Hotta, Takahisa Kondo, Toyoaki Murohara, Hideaki Toyoshima (2007)  Adiponectin level and left ventricular hypertrophy in Japanese men.   Hypertension 49: 6. 1448-1454 Jun  
Abstract: A recent study has demonstrated that adiponectin inhibited hypertrophic signaling in the myocardium of mice, implying that a decrease in the blood adiponectin level could cause cardiac muscle hypertrophy. We hypothesized that a relationship might exist between the serum adiponectin level and electrocardiographically diagnosed left ventricular hypertrophy (ECG-LVH), and we examined this hypothesis by epidemiological study of 2839 Japanese male workers who were not taking medications for hypertension. ECG-LVH was defined as meeting Sokolow-Lyon voltage criteria and/or Cornell voltage-duration product. The subjects were categorized by tertiles of serum adiponectin level, and a multivariate logistic regression analysis was conducted relating left ventricular hypertrophy to adiponectin tertiles adjusting for potential confounding factors. Prevalence of ECG-LVH in the studied sample was 16.7%. Adiponectin ranged from 1.0 to 5.0 microg/mL in the lowest category and from 7.4 to 30.6 microg/mL in the highest. Compared with subjects in the highest adiponectin category, those in the lowest one had a significantly higher prevalence of ECG-LVH independent of age, body mass index, and systolic blood pressure with an odds ratio of 1.50 and a 95% CI of 1.16 to 1.94. Further adjustment for high-density lipoprotein cholesterol, triglyceride, and insulin resistance did not change the association (odds ratio: 1.68; 95% CI: 1.28 to 2.21; P<0.001). Similar results were obtained when different criteria for ECG-LVH were used or when subjects were stratified by blood pressure or body mass index. Adiponectin concentration was inversely and independently associated with ECG-LVH in Japanese men.
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Hideki Ishii, Satoshi Ichimiya, Masaaki Kanashiro, Tetsuya Amano, Yasuhiro Ogawa, Hirotsugu Mitsuhashi, Shinichi Sakai, Tadayuki Uetani, Ryuichiro Murakami, Keiko Naruse, Toyoaki Murohara, Tatsuaki Matsubara (2007)  Effect of intravenous nicorandil and preexisting angina pectoris on short- and long-term outcomes in patients with a first ST-segment elevation acute myocardial infarction.   Am J Cardiol 99: 9. 1203-1207 May  
Abstract: Published reports have indicated that prodromal angina before acute myocardial infarction (AMI) is associated with better outcomes and that nicorandil has cardioprotective effects on ischemic hearts. We compared cardioprotective effects of intravenous nicorandil with preconditioning effects by prodromal angina in patients with AMI who underwent percutaneous coronary intervention (PCI). In total, 368 patients with first ST-elevation AMI who underwent PCI were randomly assigned to receive nicorandil 12 mg or a placebo intravenously just before PCI. Subjects were assigned to 1 of 4 groups: 52 patients with prodromal angina were given placebo, 129 patients without prodromal angina were given nicorandil, 56 patients with prodromal angina were given nicorandil, and 131 patients without prodromal angina were given placebo. Coronary microvascular impairment after PCI was prevented at similar frequencies in groups with prodromal angina and groups on nicorandil. Five-year rates for freedom from major cardiac events were similar across groups with prodromal angina given placebo, without prodromal angina given nicorandil, and with prodromal angina given nicorandil (92.3%, 93.8%, and 92.9%, respectively) but were significantly lower in the group without prodromal angina given placebo (80.2%, p = 0.0019, 0.044, and 0.042, respectively). In conclusion, intravenous administration of nicorandil before PCI exerts pharmacologic cardioprotective effects similar to ischemic preconditioning in patients with AMI.
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Matsushita, Tamakoshi, Yatsuya, Wada, Otsuka, Takefuji, Hotta, Kondo, Murohara, Toyoshima (2007)  Further inflammatory information on metabolic syndrome by adiponectin evaluation.   Int J Cardiol Apr  
Abstract: BACKGROUND: Despite a close association of adiponectin with metabolic syndrome (MetS), its usefulness as an additional MetS factor has not been well investigated. METHODS: We studied 2327 apparently healthy Japanese male office workers aged 35 to 66 years old and investigated cross-sectionally whether categorization by serum adiponectin distinguished participants' levels of high-sensitivity C-reactive protein (CRP) beyond the conventional MetS. RESULTS: In a linear regression analysis, adiponectin was associated with CRP independently of all MetS factors (beta=-0.192, P<0.001). Furthermore, a graded decrease in CRP level was observed with elevation of adiponectin in every stratum characterized by the presence or absence of each MetS component (trend P<0.05 in all strata except those of decreased high-density lipoprotein cholesterol or hyperglycemia). Similarly, geometric means of CRP levels (mg/l) decreased as adiponectin increased from the lowest to the highest tertile in all strata classified by the number of MetS components, though a P value did not reach statistical significance in those with 3 MetS components (the stratum of 0 MetS component: 0.41 [95% confidence interval, 0.34-0.49], 0.32 [0.28-0.37] and 0.26 [0.23-0.30], trend P<0.001; 1 component: 0.45 [0.39-0.52], 0.38 [0.34-0.43], and 0.32 [0.28-0.36], trend P<0.001; 2 components: 0.58 [0.50-0.67], 0.51 [0.44-0.60], and 0.46 [0.38-0.55], trend P=0.043; 3 components: 0.80 [0.66-0.96], 0.69 [0.55-0.87], and 0.58 [0.39-0.85], trend P=0.139). CONCLUSIONS: Adiponectin evaluation provides additional inflammatory information on conventional MetS, supporting the potential of hypoadiponectinemia as an additional MetS component for identifying high-risk individuals for cardiovascular disease.
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Xian Wu Cheng, Masafumi Kuzuya, Kae Nakamura, Keiko Maeda, Michitaka Tsuzuki, Weon Kim, Takeshi Sasaki, Zexuan Liu, Natsuo Inoue, Takahisa Kondo, Hai Jin, Yasushi Numaguchi, Kenji Okumura, Mitsuhiro Yokota, Akihisa Iguchi, Toyoaki Murohara (2007)  Mechanisms underlying the impairment of ischemia-induced neovascularization in matrix metalloproteinase 2-deficient mice.   Circ Res 100: 6. 904-913 Mar  
Abstract: Matrix metalloproteinases (MMPs) have been implicated in the process of neovascularization. However, the exact roles of individual MMPs in vessel formation are poorly understood. To study the putative role of MMP-2 in ischemia-induced neovascularization, a hindlimb ischemia model was applied to MMP-2(+/+) and MMP-2(-/-) mice. Serial laser Doppler blood-flow analysis revealed that the recovery of the ischemic/normal blood-flow ratio in MMP-2(-/-) young and old mice remained impaired throughout the follow-up period. At day 35, microangiography and anti-l-lectin immunohistochemical staining revealed lesser developed collateral vessels and capillary formation in both old and young MMP-2(-/-) mice compared with the age-matched MMP-2(+/+) mice. An aortic-ring culture assay showed a markedly impaired angiogenic response in MMP-2(-/-) mice, which was partially recovered by supplementation of the culture medium with recombinant MMP-2. Aorta-derived endothelial cells or bone marrow-derived endothelial progenitor cell (EPC)-like c-Kit(+) cells from MMP-2(-/-) showed marked impairment of invasive or/and proliferative abilities. At day 7, plasma and ischemic tissues of vascular endothelial growth factor protein were reduced in MMP-2(-/-). Flow cytometry showed that the numbers of EPC-like CD31(+)c-Kit(+) cells in peripheral blood markedly decreased in MMP-2-deficient mice. Transplantation of bone marrow-derived mononuclear cells from MMP-2(+/+) mice restored neovascularization in MMP-2(-/-) young mice. These data suggest that MMP-2 deficiency impairs ischemia-induced neovascularization through a reduction of endothelial cell and EPC invasive and/or proliferative activities and EPC mobilization.
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Kunihiro Matsushita, Hiroshi Yatsuya, Koji Tamakoshi, Pei Ou Yang, Rei Otsuka, Keiko Wada, Hirotsugu Mitsuhashi, Yo Hotta, Takahisa Kondo, Toyoaki Murohara, Hideaki Toyoshima (2007)  High-sensitivity C-reactive protein is quite low in Japanese men at high coronary risk.   Circ J 71: 6. 820-825 Jun  
Abstract: BACKGROUND: Although numerous studies have demonstrated a positive association of high-sensitivity C-reactive protein (CRP) with the incidence of coronary heart disease (CHD), little information exists regarding this issue in Japanese. METHODS AND RESULTS: The association between CRP and the Framingham Risk Score (FRS) was investigated in 2,523 middle-aged Japanese men without a medical history of CHD. CRP was significantly associated with this score obtained from all FRS factors. After dividing subjects into 4 categories of relative risk estimate for CHD, the geometric mean of CRP (mg/L) increased gradually with the CHD risk (below average: 0.39 [95% confidence interval, 0.37-0.41], average: 0.58 [0.50-0.67], moderately above average: 0.70 [0.57-0.86], high: 0.79 [0.58-1.09], trend p<0.001). However, it should be noted that the mean CRP concentration of the high-risk group was only 0.79 mg/L and a greater proportion (63.8%) of the high-risk subjects was in the low-risk range of CRP (<1 mg/L). CONCLUSIONS: Circulating CRP well reflect the estimated CHD risk, indicating that CRP may be useful for coronary risk stratification in Japanese also. However, the details of the CRP level in Japanese must be investigated further by prospective studies to determine the Japanese-specific cutoff points for CHD risk evaluation.
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Hajime Imai, Yasushi Numaguchi, Masakazu Ishii, Ryuji Kubota, Kazuhiko Yokouchi, Yasuhiro Ogawa, Takahisa Kondo, Kenji Okumura, Toyoaki Murohara (2007)  Prostacyclin synthase gene transfer inhibits neointimal formation by suppressing PPAR delta expression.   Atherosclerosis 195: 2. 322-332 Dec  
Abstract: OBJECTIVE: Prostacyclin (PGI(2)) is a potent ligand of peroxisome proliferator-activated receptor delta (PPAR delta) that regulates cell growth and differentiation. The aim of this study was to elucidate how endogenous PGI(2) overexpression affects the expressions of PPAR delta and mitogen-activated protein kinases (MAPKs) in the development of neointimal formation in experimental angioplasty with adenovirus-mediated PGI(2) synthase (Ad-PGIS) gene transfer. METHODS AND RESULTS: In human aortic smooth muscle cells, protein blotting analysis showed that PGI(2) overproduction decreased the levels of phosphorylated p38 MAPK (P-p38 MAPK) (2.0-fold versus 0.83-fold relative to control). Immunohistochemical analysis in balloon-injured arteries revealed diffuse expression of PPAR delta in the neointima of control vessels, with no expression in uninjured vessels. The level of PPAR delta expression was lower in Ad-PGIS-treated arteries than in control vessels, with the PPAR delta localized in the neointima adjacent to endothelium. Staining of P-p38 MAPK showed a similar pattern to PPAR delta among the three groups. Morphometric analysis at day 14 revealed that Ad-PGIS reduced the intima-to-media ratio by up to 59%. CONCLUSIONS: Ad-PGIS gene transfer reduced PPAR delta expression and inhibited neointimal formation after balloon injury in accordance with the reduction in the phosphorylation of p38 MAPK.
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Natsuo Inoue, Takahisa Kondo, Koichi Kobayashi, Mika Aoki, Yasushi Numaguchi, Masabumi Shibuya, Toyoaki Murohara (2007)  Therapeutic angiogenesis using novel vascular endothelial growth factor-E/human placental growth factor chimera genes.   Arterioscler Thromb Vasc Biol 27: 1. 99-105 Jan  
Abstract: BACKGROUND: Vascular endothelial growth factor-A (VEGF-A) promotes angiogenesis but causes adverse side effects such as edema or tissue inflammation. VEGF-E, found in the genome of the Orf virus, specifically binds to VEGF receptor-2 and shows mitotic activity on endothelial cells. Recently, we created two forms of VEGF-E and human placental growth factor (PlGF) chimera genes (VEGF-E chimera #9 and VEGF-E chimera #33), which are humanized genes with VEGF-E function but showing less antigenicity. METHODS AND RESULTS: We examined potential proangiogenic activities of these chimera genes. Four types of expression plasmids (pCDNA3.1-LacZ, phVEGF-A, pVEGF-Echimera#9, and pVEGF-Echimera#33) were administered in a rat model of hindlimb ischemia. Either pVEGF-Echimera#9, pVEGF-Echimera#33, or phVEGF-A significantly increased the ratio of ischemic/normal hindlimb blood-flow compared with the control pCDNA3.1-LacZ treated group (by 1.5-fold, 1.5-fold, and 1.4-fold, respectively, P<0.05). Histochemical staining by alkaline phosphatase also revealed that either pVEGF-Echimera#9, pVEGF-Echimera#33, or phVEGF-A increased the capillary density compared with the pCDNA3.1-LacZ treated group (1.4-fold, 1.5-fold, and 1.5-fold, respectively, P<0.05). Furthermore, immunostaining for anti-ED1 revealed that fewer macrophages had infiltrated in both pVEGF-Echimera#9 and pVEGF-Echimera#33 groups compared with the phVEGF-A group (P<0.05). CONCLUSIONS: Novel VEGF-E/human PlGF chimera genes, pVEGF-Echimera#9, and pVEGF-Echimera#33 significantly stimulated angiogenesis in response to tissue ischemia to an almost identical extent to that induced by phVEGF-A with fewer tissue inflammation responses.
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Tadayuki Uetani, Daisuke Yamashita, Juichiro Shimizu, Hiromi Misawa, Yasushi Tatematsu, Yukihisa Hamaguchi, Takehiro Miyasaka, Yuki Katanosaka, Toshiaki Kato, Tatsuaki Matsubara, Koichi Furukawa, Toyoaki Murohara, Miyako Takaki, Shinsuke Nakayama (2007)  Heart slice NMR.   Am J Physiol Heart Circ Physiol 292: 2. H1181-H1186 Feb  
Abstract: Nuclear magnetic resonance (NMR) spectroscopy of the heart is normally carried out using whole heart preparations under coronary perfusion. In such preparations, either radical changes in ionic composition of the perfusate or applications of numerous drugs would affect coronary microcirculation. This report communicates the first (31)P NMR spectroscopy study using a heart slice preparation (left ventricular slices) superfused with extracellular medium. The ratio of phosphocreatine concentration to ATP concentration was approximately 2.1. Also, intracellular pH and Mg(2+) concentration ([Mg(2+)](i)), estimated from the chemical shifts of inorganic phosphate and ATP, were comparable with those under retrograde perfusion. [Mg(2+)](i) was significantly increased by the removal of extracellular Na(+), supporting the essential role of Na(+)-coupled Mg(2+) transport in Mg(2+) homeostasis of the heart. Heart slice preparation could also be used to evaluate the potency of cardiac drugs, regardless of their possible effects on coronary microcirculation.
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Kazunori Shimizu, Akira Ito, Jong-Kook Lee, Tatsuro Yoshida, Keiko Miwa, Hisaaki Ishiguro, Yasushi Numaguchi, Toyoaki Murohara, Itsuo Kodama, Hiroyuki Honda (2007)  Construction of multi-layered cardiomyocyte sheets using magnetite nanoparticles and magnetic force.   Biotechnol Bioeng 96: 4. 803-809 Mar  
Abstract: Heart tissue engineering requires construction of three-dimensional (3-D) tissues composed of cardiomyocytes (CMs) that are tightly connected to each other. The aim of this study was to construct "scaffold-less" multi-layered 3-D CM sheets using magnetic force-based tissue engineering (Mag-TE) and to evaluate the cell-to-cell functional connections within the CM sheets. Original magnetite cationic liposomes (MCLs) with a positive surface charge (which facilitate adsorption to the target cell surface) were taken up by CMs that were isolated from 2-day-old Wistar rats. When MCLs were added to the medium of CMs at magnetite concentrations of 25, 50, and 100 pg per cell, subsequent measurements showed that 7.2, 13.2, and 27.3 pg of magnetite were taken up per cell, respectively, after 4 h incubation at 37 degrees C. Further, no toxicity was observed after a 24 h incubation period. Using magnetically labeled CMs (magnetite concentration, 100 pg/cell), multi-layered CM sheets were constructed. Immunofluorescent staining of connexin43 demonstrated the presence of gap junctions within the CM sheets that were constructed by Mag-TE. Moreover, electrical connections within the CM sheets constructed by Mag-TE were confirmed using extracellular potential mapping. These results indicate that Mag-TE is a viable methodology for heart tissue engineering.
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Junya Masuda, Keiichi Mitsuyama, Hiroshi Yamasaki, Hiroko Takedatsu, Takashi Okamura, Akira Andoh, Toyoaki Murohara, Takayuki Asahara, Michio Sata (2007)  Depletion of endothelial progenitor cells in the peripheral blood of patients with ulcerative colitis.   Int J Mol Med 19: 2. 221-228 Feb  
Abstract: There is strong evidence to suggest that endothelial progenitor cells (EPCs) play a significant role in re-endothelialization and subsequent tissue repair. This study examined the role of EPCs in inflammatory bowel disease, a disease in which impairment of mucosal healing has been implicated. Peripheral blood mononuclear cells obtained from 50 patients with ulcerative colitis (UC), 29 patients with Crohn's disease (CD), 14 patients with infectious colitis, and 35 normal control subjects were cultured in EPC medium, harvested after 7 days, and characterized by immunocytochemistry and flow cytometry. Colony assay for hematopoietic progenitor cells was also performed. Patients with active UC had a significantly decreased number of circulating EPCs as compared with healthy controls (p=0.0013), patients with inactive UC (p=0.0099), patients with active CD (p=0.0235) and patients with infectious colitis (p=0.0002). On the other hand, patients with infectious colitis had a significantly increased number of circulating EPCs as compared with healthy controls (p=0.0406), patients with active UC (p=0.0002), and patients with active CD (p=0.0316). In patients with UC, the number of circulating EPCs was correlated with the serum hemoglobin levels (r=0.485, p=0.007) and inversely with the platelet count (r=-0.372, p=0.0382). The number of hematopoietic progenitor cell colonies was comparable among patients with UC, patients with CD, patients with infectious colitis, and healthy controls. Our observations indicate that the number of circulating EPCs in patients with UC is significantly reduced. Further studies are needed to define the mechanisms that underlie the reduction in the number of circulating EPCs and to better understand the pathophysiological consequences of this event in patients with UC.
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Masahiro Kajiguchi, Takahisa Kondo, Hideo Izawa, Masayoshi Kobayashi, Koji Yamamoto, Satoshi Shintani, Yasushi Numaguchi, Tomoki Naoe, Junki Takamatsu, Kimihiro Komori, Toyoaki Murohara (2007)  Safety and efficacy of autologous progenitor cell transplantation for therapeutic angiogenesis in patients with critical limb ischemia.   Circ J 71: 2. 196-201 Feb  
Abstract: BACKGROUND: Therapeutic angiogenesis using cell transplantation (TACT) is a treatment strategy for no-option patients with critical limb ischemia (CLI). However, because one-third of treated patients fail to respond, the present study was an exploration of the characteristics of responders and non-responders to this treatment regimen. METHODS AND RESULTS: Seven CLI patients (3 with Buerger's disease, 4 with arteriosclerosis obliterans undergoing chronic hemodialysis (ASO-HD)) were treated according to the TACT protocol (n=6: bone marrow-mononuclear cells (MNCs); n=1: peripheral blood-MNCs). Subjective symptoms (visual analog scale) and objective findings (extent of ulcer, ankle-brachial pressure index, transcutaneous oxygen pressure, thermography and angiography) were assessed. Numbers of transplanted CD34+, CD133+ and CD34+ CD133+ cells were counted. Changes in circulating CD34+ and CD133+ cell numbers were also examined before and after the treatment. All responders (n=3) had Buerger's disease, and ASO-HD patients did not respond well. Among the responders, the numbers of circulating CD34+ and CD133+ cells persistently increased for 1 month after the treatment, but not in non-responders. CONCLUSIONS: The TACT regimen improved CLI in patients with Buerger's disease but not in those with ASO-HD in this small study. In responders, post procedural circulating CD34+ and CD133+ cells persistently increased for 1 month (ClinicalTrials.gov Identifier: NCT00145262, TACT-NAGOYA).
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Masayuki Torigoe, Hideo Matsui, Yasuhiro Ogawa, Hisashi Murakami, Ryuichiro Murakami, Xian Wu Cheng, Yasushi Numaguchi, Toyoaki Murohara, Kenji Okumura (2007)  Impact of the high-molecular-weight form of adiponectin on endothelial function in healthy young men.   Clin Endocrinol (Oxf) 67: 2. 276-281 Aug  
Abstract: OBJECTIVE: Adiponectin is an adipocyte-derived, antiatherogenic protein that is present in plasma as a large multimeric structure of high molecular weight (HMW) and in a trimer or hexamer form (non-HMW). The biological activities of these isoforms have not yet been elucidated. We therefore examined the effect of these isoforms on endothelial function in healthy young men. DESIGN: One hundred apparently healthy young men without overt cardiovascular disease (mean age 30 years) were recruited in this cross-sectional study based on voluntary enrollment. MEASUREMENTS: We evaluated endothelial function estimated by flow-mediated dilatation (FMD) of the brachial artery during reactive hyperaemia, and measured total and HMW adiponectin levels. RESULTS: Both HMW and non-HMW adiponectin levels showed a significant, inverse correlation with body mass index (BMI). FMD was significantly correlated with fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), malondialdehyde-modified low density lipoprotein (MDA-LDL), LDL particle size, and HMW adiponectin (r = 0.320, P = 0.001), but not non-HMW adiponectin (r = 0.125, P = 0.22). In multivariate analysis, HMW adiponectin and MDA-LDL were selected as independent factors capable of influencing FMD. No variables determined nitroglycerin-induced dilatation. CONCLUSIONS: These results suggest that even in young men, plasma adiponectin levels can predict endothelial dysfunction before any overt vascular disease has occurred. HMW adiponectin may be more useful as a marker of endothelial dysfunction than total adiponectin.
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Masahiro Muto, Takumi Yamada, Yoshimasa Murakami, Taro Okada, Mitsuhiro Okamoto, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Teruo Ito, Takahisa Kondo, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2007)  Electrophysiologic characteristics and outcome of segmental ostial superior vena cava isolation in patients with paroxysmal atrial fibrillation initiated by superior vena cava ectopy: comparison with pulmonary vein isolation.   J Electrocardiol 40: 4. 319-325 Oct  
Abstract: BACKGROUND: This study investigated the electrophysiologic characteristics and outcome of superior vena cava (SVC) segmental ostial isolation (SOI) in patients with SVC-initiated paroxysmal atrial fibrillation (PAF). METHODS: Ninety-five patients with PAF underwent pulmonary vein (PV) SOI using a basket catheter whether the PAF originating from PVs was observed or not. Fifteen of those patients also underwent SVC SOI in the same manner due to evidence of SVC origin PAF. RESULTS: The SVC musculature networks and electrical connections with the atrium (multiple separate electrical connections in 10, multiple separate musculature networks with separate electrical connections in 1, and a continuous broad electrical connection in 4 SVCs) were similar to those of the PV musculature. However, the occurrence of an electrical connection recovery after SOI in patients with recurrent atrial fibrillation was lower for SVCs (25%) than PVs (58%). CONCLUSIONS: Superior vena cava SOI appears to have a lower recurrent conduction rate than PV SOI.
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Mitsutoshi Oguri, Kimihiko Kato, Takeshi Hibino, Kiyoshi Yokoi, Tomonori Segawa, Hitoshi Matsuo, Sachiro Watanabe, Yoshinori Nozawa, Toyoaki Murohara, Yoshiji Yamada (2007)  Genetic risk for restenosis after coronary stenting.   Atherosclerosis 194: 2. e172-e178 Oct  
Abstract: OBJECTIVES: The purpose of the present study was to identify gene polymorphisms that confer susceptibility to restenosis after bare-metal stenting of coronary arteries, and thereby to predict the genetic risk for this condition. METHODS AND RESULTS: The study population comprised 461 unrelated Japanese individuals (350 men, 111 women) who underwent stent implantation, including 107 subjects who developed in-stent restenosis and 354 subjects without this condition. The genotypes for 142 polymorphisms of 121 candidate genes were determined with a method that combines the polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. Multivariate logistic regression analysis with adjustment for the prevalence of diabetes mellitus revealed that the 1615G-->A polymorphism of BCHE, the 7,067,365C-->A polymorphism of INSR, the C-->T polymorphism of GPX1, the G-->A polymorphism of ROS1, and the G-->A polymorphism of MMP9 were associated (P<0.05) with in-stent restenosis. Further analysis with adjustment both for the prevalence of diabetes mellitus and for quantitative coronary angiographic measurements revealed that the BCHE, GPX1, and ROS1 genotypes were independently associated (P<0.05) with in-stent restenosis. CONCLUSIONS: Determination of the genotypes for BCHE, GPX1, and ROS1 may prove informative for assessment of the genetic risk for in-stent restenosis.
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Mikito Takefuji, Kazutaka Mori, Yasuhiro Morita, Nariko Arimura, Takashi Nishimura, Masanori Nakayama, Mikio Hoshino, Akihiro Iwamatsu, Toyoaki Murohara, Kozo Kaibuchi, Mutsuki Amano (2007)  Rho-kinase modulates the function of STEF, a Rac GEF, through its phosphorylation.   Biochem Biophys Res Commun 355: 3. 788-794 Apr  
Abstract: Rho family GTPases are key regulators of various physiological processes. Several recent studies indicated that the antagonistic relationship between Rho and Rac is essential for cell polarity and that the Rac activity is negatively regulated by Rho. In this study, we found that Rho-kinase, an effector of Rho, counteracted the Rac GEF STEF-induced Rac1 activation in COS7 cells. Rho-kinase phosphorylated STEF at Thr1662 in vitro, and Y-27632, a Rho-kinase inhibitor, suppressed lysophosphatidic acid-induced phosphorylation of STEF in PC12D cells. STEF interacted with specific molecules such as microtubule-associated protein 1B, and the phosphorylation of STEF by Rho-kinase diminished its interaction with these molecules. STEF promoted nerve growth factor-induced neurite outgrowth in PC12D cells, while the phosphomimic mutant of STEF had a weakened ability to enhance neurite outgrowth. Taken together, these results suggest that the phosphorylation of STEF by Rho-kinase exerts the inhibitory effect on the function of STEF.
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Yuzo Hayashi, Kenji Okumura, Hideo Matsui, Akiko Imamura, Manabu Miura, Ryotaro Takahashi, Ryuichiro Murakami, Yasuhiro Ogawa, Yasushi Numaguchi, Toyoaki Murohara (2007)  Impact of low-density lipoprotein particle size on carotid intima-media thickness in patients with type 2 diabetes mellitus.   Metabolism 56: 5. 608-613 May  
Abstract: Small low-density lipoprotein (LDL) particles and modifications to LDL such as glycation and oxidation have been linked to the pathogenesis of atherosclerosis in patients with diabetes. We investigated whether LDL particle size, or the levels of glycated LDL or malondialdehyde-modified LDL (MDA-LDL) are associated with carotid intima-media thickness (IMT) in patients with type 2 diabetes mellitus. One hundred seventy-two patients with type 2 diabetes mellitus were enrolled. Carotid IMT was measured by high-resolution ultrasound, and LDL particle size and serum glycated LDL and MDA-LDL levels were determined. The 3 variables were significantly correlated with one another. Univariate analyses defined statistically significant correlations of carotid IMT with LDL size, hemoglobin A(1c), glycated LDL, MDA-LDL, high-density lipoprotein (HDL) cholesterol, and age. The strongest association of IMT was with LDL size (r = -0.406, P < .0001), followed by that with HDL cholesterol (r = -0.225, P = .004). A stepwise multiple regression analysis revealed that LDL size and HDL cholesterol are independent predictors of carotid IMT. Neither glycated LDL nor MDA-LDL had a significant independent contribution to the severity of carotid IMT in the multivariate model. Low-density lipoprotein particle size, but not the glycated LDL or MDA-LDL level, was independently associated with carotid IMT in patients with type 2 diabetes mellitus regardless of antidiabetic and lipid-lowering medications. These results suggest that the measurement of LDL size may be more useful than quantification of modified LDLs for assessing atherosclerosis in patients with type 2 diabetes mellitus. Small LDL particles may be the most important predictor for the risk of cardiovascular disease in diabetic patients.
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Akiko Noda, Seiichi Nakata, Yasuo Koike, Seiko Miyata, Kiyoyuki Kitaichi, Takao Nishizawa, Kohzo Nagata, Fumihiko Yasuma, Toyoaki Murohara, Mitsuhiro Yokota (2007)  Continuous positive airway pressure improves daytime baroreflex sensitivity and nitric oxide production in patients with moderate to severe obstructive sleep apnea syndrome.   Hypertens Res 30: 8. 669-676 Aug  
Abstract: Individuals with obstructive sleep apnea syndrome (OSAS) are at high risk for cardiovascular morbidity and mortality. The effects of OSAS severity and nocturnal continuous positive airway pressure (CPAP) on daytime baroreflex sensitivity (BRS) and nitric oxide (NO) production were investigated in OSAS patients. Fifty-one consecutive males with OSAS and 29 age-matched healthy men underwent the Valsalva test and standard polysomnography. Patients with an apnea-hypopnea index (AHI) of >or=20 episodes per hour were randomized to receive CPAP treatment for 3 months (n=14) or no such treatment (n=19). The BRS index measured from the overshoot phase (phase IV) of the Valsalva maneuver and plasma NO concentration were significantly lower, whereas the AHI, oxygen desaturation time, arousal index, percentage of sleep stage 1, and systolic blood pressure were significantly greater, in patients with an AHI of >or=20/h than in those with an AHI of <20/h or in controls. The 24-h urinary excretion of norepinephrine was significantly reduced and the plasma NO concentration was significantly increased after one night of CPAP. The BRS index for phase IV and the Valsalva ratio were significantly increased in the CPAP group after the 3-month treatment period but remained unchanged in the non-CPAP group of OSAS patients. The daytime BRS index and NO production were thus inversely related to the severity of OSAS, and successful CPAP treatment improved these parameters in patients with moderate to severe OSAS. CPAP may therefore reduce the risk of cardiovascular complications due to endothelial dysfunction or increased sympathetic activity.
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Masayuki Shimano, Yukiomi Tsuji, Yukihiko Yoshida, Yasuya Inden, Naoya Tsuboi, Teruo Itoh, Hirohiko Suzuki, Takashi Muramatsu, Taro Okada, Shuji Harata, Takumi Yamada, Haruo Hirayama, Stanley Nattel, Toyoaki Murohara (2007)  Acute and chronic effects of cardiac resynchronization in patients developing heart failure with long-term pacemaker therapy for acquired complete atrioventricular block.   Europace 9: 10. 869-874 Oct  
Abstract: AIMS: We assessed the effects of cardiac re-synchronization therapy (CRT) in patients who developed otherwise unexplained heart failure (HF) during right ventricular apical (RVA)-pacing for acquired complete atrioventricular block (CAVB). METHODS AND RESULTS: Eighteen consecutive CAVB patients with HF during RVA-pacing were assessed with haemodynamic studies immediately and 12 months after CRT-upgrade. Ten patients had idiopathic CAVB and 13 showed normal left ventricular (LV) function at RVA-pacemaker implantation. HF developed after 81 +/- 10 months. RVA-pacing duration correlated (r = 0.49, P < 0.05) with LV ejection fraction (LVEF) deterioration. Biventricular- (BiV) and LV-pacing acutely improved the systolic function comparably, but only BiV improved diastolic function. One-year post-CRT-initiation, New York Heart Association classification improved 35 +/- 3% (P < 0.05) and the number of hospitalizations decreased 85 +/- 3% (P < 0.0001). CRT decreased LV end-diastolic diameter (LVEDd) 7 +/- 2% (P < 0.01) and increased LVEF by 23 +/- 7% (P < 0.01). The CRT-induced reduction in LVEDd tended to be greater in patients with RVA-pacing for < 5 years vs. > 5 years (7.7 +/- 2.5 vs. 3.6 +/- 1.0 mm, P = 0.08). CONCLUSION: CRT-upgrade improves the cardiac function and symptoms in CAVB patients with HF progression related to RVA-pacing. Because adverse LV-remodelling may be partly irreversible, consideration should be given to BiV- and LV-pacing upgrade as soon as possible after the indications appear, and prospective studies of the optimal timing of CRT-upgrade may be useful.
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Takumi Yamada, Yoshimasa Murakami, Naoki Yoshida, Taro Okada, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Masahiro Muto, Yasuya Inden, Makoto Hirai, Toyoaki Murohara, Hugh T McElderry, Andrew E Epstein, Vance J Plumb, G Neal Kay (2007)  Efficacy of electroanatomic mapping in the catheter ablation of premature ventricular contractions originating from the right ventricular outflow tract.   J Interv Card Electrophysiol 19: 3. 187-194 Sep  
Abstract: BACKGROUND: Mapping of premature ventricular contractions (PVCs) originating from the right ventricular outflow tract (RVOT) sometimes is not easy because of an unstable incidence and multiple foci of the PVCs. The aim of this study was to evaluate the effectiveness of electroanatomic mapping in catheter ablation of those PVCs. METHODS AND RESULTS: One hundred patients with 134 RVOT origin PVCs were randomly allotted to undergo either conventional (group I; 50 patients with 65 PVCs) or electroanatomic mapping (group II; 50 patients with 69 PVCs). In group II, electroanatomic mapping of the RVOT was performed using auto-freeze maps in patients with frequent PVCs, and pace mapping was performed marking the pacing sites on the remap which was made by extracting the anatomic frame out of the baseline map during sinus rhythm in patients with infrequent PVCs. Successful ablation was achieved in 44 (88%) group I patients and 48 (96%) group II patients (p = 0.14). The fluoroscopy and procedure times and those per PVC morphology were all significantly shorter in group II than group I overall (p < 0.0001 for all comparisons), and in each patient group with infrequent PVCs, frequent PVCs or unstable PVCs (p < 0.05-0.0001). The number of RF applications and that per PVC was significantly smaller in group II than group I (5.3 +/- 1.8 vs 6.2 +/- 2.4, and 4.4 +/- 1.2 vs 5.2 +/- 2.1; p < 0.05). CONCLUSIONS: The use of electroanatomic mapping may reduce the fluoroscopy and procedure times in the ablation of RVOT PVCs, but there is no evidence that it improves the overall efficacy of the procedure.
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Mitsutoshi Oguri, Kimihiko Kato, Takeshi Hibino, Kiyoshi Yokoi, Tomonori Segawa, Hitoshi Matsuo, Sachiro Watanabe, Yoshinori Nozawa, Toyoaki Murohara, Yoshiji Yamada (2007)  Identification of a polymorphism of UCP3 associated with recurrent in-stent restenosis of coronary arteries.   Int J Mol Med 20: 4. 533-538 Oct  
Abstract: The purpose of the present study was to identify gene polymorphisms that confer susceptibility to recurrent restenosis after bare-metal stenting of coronary arteries, and thereby to assess the genetic risk for this condition. The study population comprised 527 unrelated Japanese individuals, including 28 subjects who developed in-stent restenosis two or more times and 499 subjects without restenosis. The genotypes for 142 polymorphisms of 121 candidate genes were determined with a method that combines the polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. Eleven polymorphisms were related (P<0.05) to the prevalence of recurrent in-stent restenosis as determined by the Chi-square test. Multivariable logistic regression analysis with adjustment for age, sex, body mass index, and the prevalence of smoking, hypertension, diabetes mellitus, and hypercholesterolemia revealed that the -55Cright curved arrow T polymorphism of the uncoupling protein 3 gene (UCP3) was significantly (P=0.0006 in a recessive model) associated with the prevalence of recurrent in-stent restenosis, with the T allele representing a risk factor for this condition. A stepwise forward selection procedure showed that the UCP3 genotype significantly (P=0.0014, recessive model) affected the prevalence of recurrent in-stent restenosis. Determination of the genotype for UCP3 may thus contribute to assessment of the genetic risk for recurrent in-stent restenosis.
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Shingo Ai, Xian Wu Cheng, Aiko Inoue, Kae Nakamura, Kenji Okumura, Akihisa Iguchi, Toyoaki Murohara, Masafumi Kuzuya (2007)  Angiogenic activity of bFGF and VEGF suppressed by proteolytic cleavage by neutrophil elastase.   Biochem Biophys Res Commun 364: 2. 395-401 Dec  
Abstract: Neutrophil elastase (NE), a serine protease released from the azurophil granules of activated neutrophil, proteolytically cleaves multiple cytokines, and cell surface proteins. In the present study, we examined whether NE affects the biological abilities of angiogenic growth factors such as basic-fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF). NE degraded bFGF and VEGF in a time- and concentration-dependent manner, and these degradations were suppressed by sivelestat, a synthetic inhibitor of NE. The bFGF- or VEGF-mediated proliferative activity of human umbilical vein endothelial cells was inhibited by NE, and the activity was recovered by sivelestat. Furthermore, NE reduced the bFGF- or VEGF-induced tubulogenic response of the mice aortas, ex vivo angiogenesis assay, and these effects were also recovered by sivelestat. Neutrophil-derived NE degraded potent angiogenic factors, resulting in loss of their angiogenic activity. These findings provide additional insight into the role played by neutrophils in the angiogenesis process at sites of inflammation.
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Takumi Yamada, Yoshimasa Murakami, Taro Okada, Naoki Yoshida, Yuichi Ninomiya, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Yasuya Inden, Makoto Hirai, Toyoaki Murohara, Hugh T McElderry, Andrew E Epstein, Vance J Plumb, G Neal Kay (2007)  Non-pulmonary vein epicardial foci of atrial fibrillation identified in the left atrium after pulmonary vein isolation.   Pacing Clin Electrophysiol 30: 11. 1323-1330 Nov  
Abstract: BACKGROUND: Pulmonary vein (PV) isolation (PVI) has been demonstrated to be an effective technique for curing atrial fibrillation (AF). AF foci that cannot be isolated by PVI (non-PV foci) can become the cause of AF recurrence. The purpose of this study was to investigate the characteristics of non-PV AF foci. METHODS AND RESULTS: Two hundred consecutive patients with symptomatic AF underwent electrophysiologic studies. In all patients, successful ostial or antral PVI was achieved with a multielectrode basket catheter (MBC). In 45 patients, spontaneous AF was induced even after PVI. In 23 of those patients, 30 AF foci were found in the left atrium (LA) (12 in the PV antrum, and 18 in the LA wall). Twenty-six of those foci were eliminated by focal ablation guided by an MBC. Five of those foci (four in the PV antrum and one in the LA posterior wall) were speculated to be located epicardially because a small potential preceding the LA potential was recorded from the MBC electrodes during AF initiation at the successful ablation site where single large potentials were recorded during sinus rhythm and a longer duration of radiofrequency energy delivery was needed to eliminate them. CONCLUSIONS: MBC mapping with induction of spontaneous AF may be useful for identifying non-PV AF foci in the LA after PVI. In some of those non-PV foci, mainly around the PVI lesions, a few electrophysiologic findings suggesting an epicardial location were observed. This may be a rationale for the efficacy of extensive PV ablation.
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Li, Kondo, Numaguchi, Kobayashi, Aoki, Inoue, Okumura, Murohara (2007)  Role of Bradykinin, Nitric Oxide, and Angiotensin II Type 2 Receptor in Imidapril-Induced Angiogenesis.   Hypertension Dec  
Abstract: The angiotensin II (Ang II)-Ang II type 1 receptor pathway is proangiogenic, whereas studies showed that some angiotensin-converting enzyme inhibitors also stimulate angiogenesis in the setting of tissue ischemia, leaving a controversy of Ang II-mediated angiogenesis. We investigated whether an angiotensin-converting enzyme inhibitor imidapril-induced angiogenesis might be mediated via the tissue bradykinin pathway. To rule out the conventional effects of Ang II on angiogenesis, we used Ang II type 1a receptor knockout (AT1aKO) mice. We examined the effects of the angiotensin-converting enzyme inhibitor imidapril on angiogenesis in a hindlimb ischemia model using AT1aKO mice. After induction of hindlimb ischemia, AT1aKO mice were treated with or without imidapril (1.0 or 0.1 mg/kg per day for 21 days). Angiogenesis was quantified by laser Doppler blood flowmetry and capillary density. Angiogenesis was reduced in AT1aKO mice compared with wild-type mice. Imidapril with either low or high doses enhanced angiogenesis in AT1aKO mice (P<0.01). Ang II type 2 receptor antagonist (PD123319; 30 mg/kg per day) and B1 receptor antagonist (DesArg9-[Leu8]-bradykinin; 50 nmol/kg per day) suppressed the imidapril-induced angiogenesis in AT1aKO mice to an extent even lower than that of nontreated AT1aKO mice. B2 receptor antagonist (Hoechst 140; 100 microg/kg/d) and NO synthase inhibitor (N(G)-nitro-L-arginine methyl ester; 20 mg/kg per day) moderately attenuated the imidapril-mediated angiogenesis. RT-PCR revealed that vascular endothelial growth factor receptor 2 mRNA was reduced with PD123319, DesArg9-[Leu8]-bradykinin, or Hoechst 140, and vascular endothelial growth factor mRNA abundance was suppressed with PD123319 or DesArg9-[Leu8]-bradykinin. In conclusion, imidapril elicited angiogenesis in the setting of tissue ischemia in AT1aKO mice. This angiogenic effect might involve the Ang II-Ang II type 2 receptor pathway in addition to the bradykinin-B1 and bradykinin-B2 receptor/NO-dependent pathways.
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Hamaguchi, Matsubara, Amano, Uetani, Asano, Iwamoto, Furukawa, Murohara, Nakayama (2007)  Na(+)-independent Mg(2+) Transport Sensitive to 2-Aminoethoxydiphenyl Borate (2-APB) in Vascular Smooth Muscle Cells: Involvement of TRPM-like Channels.   J Cell Mol Med Nov  
Abstract: Magnesium is associated with several important cardiovascular diseases. There is an accumulating body of evidence verifying the important roles of Mg(2+)-permeable channels. In the present study, we estimated the intracellular free Mg(2+) concentration ([Mg(2+)](i)) using 31P-NMR in porcine carotid arteries. pH(i) and intracellular phosphorus compounds were simultaneously monitored. Removal of extracellular divalent cations (Ca(2+) and Mg(2+)) in the absence of Na(+) caused a gradual decrease in [Mg(2+)](i) to approximately 60% of the control value after 125 min. On the other hand, the simultaneous removal of extracellular Ca(2+) and Na(+) in the presence of Mg(2+) gradually increased [Mg(2+)](i) in an extracellular Mg(2+)-dependent manner. 2-aminoethoxydiphenyl borate (2-APB) attenuated both [Mg(2+)](i) load and depletion caused under Na(+)- and Ca(2+)-free conditions. Neither [ATP](i) nor pH(i) correlated with changes in [Mg(2+)](i). RT-PCR detected transcripts of both TRPM6 and TRPM7, although TRPM7 was predominant. In conclusion, the results suggest the presence of Mg(2+)-permeable channels of TRPM family that contribute to Mg(2+) homeostasis in vascular smooth muscle cells. The low, basal [Mg(2+)](i) level in vascular smooth muscle cells is attributable to the relatively low activity of this Mg(2+) entry pathway.
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Mizutani, Ishii, Hattori, Nomura, Numaguchi, Tsujimoto, Kobayshi, Murohara, Wright (2007)  New insights into the importance of aminopeptidase A in hypertension.   Heart Fail Rev Nov  
Abstract: The renin-angiotensin system (RAS) plays an important role in the maintenance of normal blood pressure and the etiology of hypertension; however, minimal attention has been paid to the degradation of the effector peptide, angiotensin II (AngII). Since aminopeptidase A (APA)-deficient mice develop hypertension APA appears to be an essential enzyme in the control of blood pressure via degradation of AngII. The robust hypertension seen in the spontaneously hypertensive rat (SHR) is due to activation of the RAS, and an accompanying decrease in kidney APA. Changes in APA have also been measured during the activation of the RAS in the Goldblatt hypertension model and Dahl salt-sensitive (DSS) rat. The DSS rat shows an elevation in renal APA activity at the onset of hypertension suggesting a protective role against elevations in circulating AngII, followed by decreased APA activity with advancing hypertension. Changes seen in human maternal serum APA activity during preeclampsia are similar to changes measured in renal APA in the DSS rat model. APA activity is higher than during normal pregnancy at the onset of preeclampsia, and with advancing preeclampsia (severe preeclampsia) declines below that seen during normal pregnancy. Serum APA activity is also increased during hormone replacement therapy (HRT), perhaps in reaction to elevated levels of AngII. Thus, it appears important to consider the relationship among activation of the RAS, circulating levels of AngII, and the availability of APA in hypertensive disorders.
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Takumi Yamada, Yoshimasa Murakami, Taro Okada, Naoki Yoshida, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2007)  Pulmonary vein antrum not always coaxial to the pulmonary vein: a dimensional pitfall to the circumferential isolation technique.   Circ J 71: 9. 1430-1436 Sep  
Abstract: BACKGROUND: The dimensions and electrophysiological characteristics of the antral region of human pulmonary veins (PVs) were investigated. METHODS AND RESULTS: Fifty-five consecutive patients with symptomatic paroxysmal atrial fibrillation underwent PV isolation targeting the PV antrum potentials with a 31 mm multielectrode basket catheter (MBC). The most distal and proximal electrode pairs along the MBC spline where radiofrequency ablation was carried out were identified and the longitudinal distance between those ablation sites (Ld) was measured. When the Ld was > or =6 mm, the PV antrum was defined as noncoaxial. In 56% of the left superior PVs, 42% of the right superior PVs, 63% of the left inferior PVs and 56% of the right inferior PVs, a noncoaxial PV antrum was identified. In each PV, the radiofrequency ablation delivery duration and energy to complete the PV antrum isolation were significantly larger in the PVs with a noncoaxial PV antrum than in those with a coaxial PV antrum. CONCLUSION: The PV antrum is noncoaxial to the PV in >50% of the PVs, a feature that may increase the complexity of the circumferential isolation technique.
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Takumi Yamada, Yoshimasa Murakami, Yukihiko Yoshida, Taro Okada, Naoki Yoshida, Junji Toyama, Naoya Tsuboi, Yasuya Inden, Makoto Hirai, Toyoaki Murohara, Hugh T McElderry, Andrew E Epstein, Vance J Plumb, G Neal Kay (2007)  Electrophysiologic and electrocardiographic characteristics and radiofrequency catheter ablation of focal atrial tachycardia originating from the left atrial appendage.   Heart Rhythm 4: 10. 1284-1291 Oct  
Abstract: BACKGROUND: The left atrial appendage (LAA) is one of the major sources of focal atrial tachycardias (ATs). OBJECTIVE: The purpose of this study was to investigate the detailed electrophysiologic characteristics and catheter ablation of focal ATs originating from the LAA. METHODS: The study population consisted of 47 consecutive patients with 50 focal ATs originating from the left atrium (LA): LAA in 13, left pulmonary veins (PVs) in 14, right PVs in 12, and mitral annulus in 11. Programmed electrical stimulation and pharmacologic testing were performed to examine the mechanism of LAA AT. Left atriography was performed prior to radiofrequency ablation to identify the focus in the LAA. RESULTS: The mechanism of LAA AT was automaticity in 11 and triggered activity in 2. The 13 LAA foci were located mainly at the LAA base: 11 on the medial side and 2 on the lateral side. Atrial activation sequences within the distal coronary sinus were helpful in differentiating these LAA foci. The criterion of a negative P wave in leads I and aVL indicating an LAA AT focus was associated with sensitivity of 92.3%, specificity 97.3%, positive predictive value 92.3%, and negative predictive value 97.3%. No complications occurred in any of the 13 patients. All 13 patients were free of atrial arrhythmias without any antiarrhythmic drugs during follow-up of 8 +/- 3 years. CONCLUSION: LAA ATs have typical electrophysiologic and electrocardiographic characteristics that are helpful in guiding radiofrequency catheter ablation.
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Yutaka Saito, Ken-ichiro Sasaki, Yousuke Katsuda, Toyoaki Murohara, Yoshiaki Takeshita, Teiji Okazaki, Ken Arima, Yoshio Katsuki, Satoshi Shintani, Toshifumi Shimada, Hidetoshi Akashi, Hisao Ikeda, Tsutomu Imaizumi (2007)  Effect of autologous bone-marrow cell transplantation on ischemic ulcer in patients with Buerger's disease.   Circ J 71: 8. 1187-1192 Aug  
Abstract: BACKGROUND: Thromboangiitis obliterans, also known as Buerger's disease, is characterized by peripheral occlusive changes in the arteries of the upper and lower limbs and treatment is often ineffective. Intramuscular transplantation of autologous bone marrow-mononuclear cells (BM-MNC) has been recently reported as improving the symptoms and clinical manifestations in patients with severely ischemic limbs, mostly caused by arteriosclerosis obliterans. The present study focused on the patients with Buerger's disease presenting with rest pain and/or skin ulcer uncontrolled by conventional treatments. METHODS AND RESULTS: Fourteen patients with Buerger's disease (Fontaine III: n=2, Fontaine IV: n=12) underwent transplantation of autologous BM-MNC into ischemic skeletal muscles of either the upper or lower limb. After 4 weeks, rest pain was significantly reduced. In 19 skin ulcers of 9 patients, 8 ulcers were healed and 8 were diminished in the size. These improvements were maintained for 24 weeks without complications. CONCLUSIONS: In patients with Buerger's disease, intramuscular transplantation of autologous BM-MNC improved symptoms and clinical manifestations, especially skin ulcer.
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Takumi Yamada, Yoshimasa Murakami, Naoki Yoshida, Taro Okada, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Masahiro Muto, Yasuya Inden, Makoto Hirai, Toyoaki Murohara, Hugh T McElderry, Andrew E Epstein, Vance J Plumb, G Neal Kay (2007)  Preferential conduction across the ventricular outflow septum in ventricular arrhythmias originating from the aortic sinus cusp.   J Am Coll Cardiol 50: 9. 884-891 Aug  
Abstract: OBJECTIVES: The purpose of this study was to examine the relationship between the origin and breakout site of idiopathic ventricular tachycardia (VT) or premature ventricular contractions (PVCs) originating from the myocardium around the ventricular outflow tract. BACKGROUND: The myocardial network around the ventricular outflow tract is not well known. METHODS: We studied 70 patients with idiopathic VT (n = 23) or PVCs (n = 47) with a left bundle branch block and inferior QRS axis morphology. Electroanatomical mapping was performed in both the right ventricular outflow tract (RVOT) and aortic sinus cusp (ASC) during VT or PVCs. RESULTS: The earliest ventricular activation (EVA) was recorded in the RVOT in 55 patients (group R) and in the ASC in 15 (group A). In all group R patients, the closest pace map and successful ablation were achieved at the EVA site. Although a successful ablation was achieved at the EVA site in all group A patients, the closest pace map was obtained at the EVA site in 8 and RVOT in 7 (with an excellent pace map in 4). The stimulus to QRS interval was 0 ms during pacing from the RVOT and 36 +/- 8 ms from the ASC. The distance between the EVA and perfect pace map sites in those 4 patients was 11.9 +/- 3.0 mm. CONCLUSIONS: Ventricular arrhythmias originating from the ASC often show preferential conduction to the RVOT, which may render pace mapping or some algorithms using the electrocardiographic characteristics less reliable. In some of those cases, an insulated myocardial fiber across the ventricular outflow septum may exist.
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Toru Nakamura, Takuji Torimura, Masaharu Sakamoto, Osamu Hashimoto, Eitaro Taniguchi, Kinya Inoue, Ryuichiro Sakata, Ryukichi Kumashiro, Toyoaki Murohara, Takato Ueno, Michio Sata (2007)  Significance and therapeutic potential of endothelial progenitor cell transplantation in a cirrhotic liver rat model.   Gastroenterology 133: 1. 91-107.e1 Jul  
Abstract: BACKGROUND & AIMS: We investigated whether endothelial progenitor cell (EPC) transplantation could reduce established liver fibrosis and promote hepatic regeneration by isolating rat EPCs from bone marrow cells. METHODS: Recipient rats were injected intraperitoneally with carbon tetrachloride (CCl(4)) twice weekly for 6 weeks before initial administration of EPCs. CCl(4) was then readministered twice weekly for 4 more weeks, and EPC transplantation was carried out for these same 4 weeks. RESULTS: At 7 days in culture, the cells expressed Thy-1, CD31, CD133, Flt-1, Flk-1, and Tie-2, suggesting an immature endothelial lineage. Immunohistochemical analyses showed fluorescent-labeled, transplantation EPCs were incorporated into the portal tracts and fibrous septa. Single and multiple EPC transplantation rats had reduced liver fibrosis, with decreased alpha2-(I)-procollagen, fibronectin, transforming growth factor-beta, and alpha-smooth muscle actin-positive cells. Film in situ zymographic analysis revealed strong gelatinolytic activity in the periportal area, in accordance with EPC location. Real-time polymerase chain reaction analysis of multiple EPC-transplantation livers showed significantly increased messenger RNA levels of matrix metalloproteinase (MMP)-2, -9 and -13, whereas tissue inhibitor of metalloproteinase-1 expression was significantly reduced. Expression of hepatocyte growth factor, transforming growth factor-alpha, epidermal growth factor, and vascular endothelial growth factor was increased in multiple EPC-transplantation livers, while hepatocyte proliferation increased. Transaminase, total bilirubin, total protein, and albumin levels were maintained in EPC-transplantation rats, significantly improving survival rates. CONCLUSIONS: We conclude that single or repeated EPC transplantation halts established liver fibrosis in rats by suppressing activated hepatic stellate cells, increasing matrix metalloproteinase activity, and regulating hepatocyte proliferation.
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Takumi Yamada, Yoshimasa Murakami, Taro Okada, Naoki Yoshida, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2007)  Plasma brain natriuretic peptide level after radiofrequency catheter ablation of paroxysmal, persistent, and permanent atrial fibrillation.   Europace 9: 9. 770-774 Sep  
Abstract: AIMS: The aim of this study was to investigate the change in plasma brain natriuretic peptide (BNP) level after pulmonary vein isolation (PVI) in paroxysmal (PAF), persistent (Pers-AF), and permanent atrial fibrillation (AF) (Perm-AF) patients. METHODS AND RESULTS: In 96 lone AF patients (PAF=65, Pers-AF=17, and Perm-AF=14), BNP was measured before and 3 months after successful PVIs. At baseline, in all patients, BNP was elevated and was significantly greater in Pers-AF and Perm-AF patients than PAF patients (P<0.05). After 3 months of follow-up following multiple PVIs, AF recurred in 12 (18%) PAF, 7 (41%) Pers-AF, and 8 (57%) Perm-AF patients. In Pers-AF and Perm-AF patients, BNP at baseline did not predict AF recurrence. After the PVIs, BNP significantly decreased in PAF and Pers-AF patients (P=0.005) but not in Perm-AF patients. An elevated BNP at baseline decreased to within-normal limits in all Pers-AF and Perm-AF patients without AF recurrences. In all seven (23%) patients, whose AF type improved after the PVIs, BNP decreased. CONCLUSION: The reduction in the BNP level after the PVI seemed to be a marker for a good outcome in AF post-ablation patients.
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Ryotaro Takahashi, Toru Asai, Hisashi Murakami, Ryuichiro Murakami, Michitaka Tsuzuki, Yasushi Numaguchi, Hideo Matsui, Toyoaki Murohara, Kenji Okumura (2007)  Pressure overload-induced cardiomyopathy in heterozygous carrier mice of carnitine transporter gene mutation.   Hypertension 50: 3. 497-502 Sep  
Abstract: Primary systemic carnitine deficiency is an autosomal recessive disorder caused by a decreased renal reabsorption of carnitine because of mutations of the carnitine transporter OCTN2 gene, and hypertrophic cardiomyopathy is a common clinical feature of homozygotes. Although heterozygotes for OCTN2 mutations are generally healthy with normal cardiac performance, heterozygotes may be at risk for cardiomyopathy in the presence of additional risk factors, such as hypertension. To test this hypothesis, we investigated the effects of surgically induced pressure overload on the hearts of heterozygous mutants of a murine model of OCTN2 mutation, juvenile visceral steatosis mouse (jvs/+). Eleven-week-old jvs/+ mice and age-matched wild-type mice were used. At baseline, there were no differences in physical characteristics between wild-type and jvs/+ mice. However, plasma and myocardial total carnitine levels in jvs/+ mice were lower than in wild-type mice. Both wild-type and jvs/+ mice were subjected to ascending aortic constriction with or without 1% l-carnitine supplementation for 4 weeks. At 4 weeks after ascending aortic constriction, jvs/+ mice showed an exaggeration of cardiac hypertrophy and pulmonary congestion, further increased gene expression of atrial natriuretic peptide in the left ventricles, further deterioration of left ventricular fractional shortening, reduced myocardial phosphocreatine:adenosine triphosphate ratio, and increased mortality compared with wild-type mice; l-carnitine supplementation prevented these changes in jvs/+ mice subjected to ascending aortic constriction. In conclusion, cardiomyopathy and heart failure with energy depletion may be induced by pressure overload in heterozygotes for OCTN2 mutations and could be prevented by l-carnitine supplementation.
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Umeda, Iwase, Izawa, Katoh, Gochi, Toyama, Yokoya, Matsushita, Ishiki, Inagaki, Murohara, Yokota (2007)  Is it possible to predict which patients need distal protection during primary angioplasty?   Int J Cardiol Aug  
Abstract: BACKGROUND: Although the benefit of distal protection (DP) during primary percutaneous coronary intervention (PCI) remains questionable, there appears to be efficacy in some clinical situations. We sought to identify in patients with ST-segment elevation acute myocardial infarction (STEMI) which clinical and angiographic characteristics might indicate the patient who will benefit from the use of a DP device. METHODS: A series of 103 consecutive patients with STEMI undergoing primary PCI using DP were compared with 98 consecutive patients treated by primary PCI alone. RESULTS: The overall rates of thromboembolic complications and achievement of optimal reperfusion (myocardial blush grade >/=2 and ST-segment resolution >/=70%), and infarct size, were similar between the 2 groups. However, DP use was associated with higher rates of optimal reperfusion in patients with right coronary artery (RCA) lesions (OR 2.45; 95% CI, 1.07 to 5.59; P=0.034), thrombus score >/=4 (OR 2.64; 95% CI, 1.07 to 6.50; P=0.034) or infarct-related artery (IRA) of >/=3.5 mm in diameter (OR 4.09; 95% CI, 1.02 to 16.40; P=0.047). In this population (RCA location, thrombus score >/=4, or IRA >/=3.5 mm), DP use reduced the risk of thromboembolic complications (64%, P=0.012, 45%, P=0.035 and 54%, P=0.050, respectively), resulting in a smaller infarct size (8.0+/-5.1 vs. 11.7+/-7.5, P=0.028, 13.1+/-8.8 vs. 17.4+/-10.0, P=0.026 and 15.5+/-10.8 vs. 22.1+/-10.1, P=0.042, respectively). CONCLUSIONS: The use of a DP during primary PCI may lead to a reduction of thromboembolic complications, subsequent higher rates of optimal reperfusion and reduced infarct size in patients with RCA culprit lesions, a large thrombus, or large IRA.
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Takaaki Yamada, Takahisa Kondo, Yasushi Numaguchi, Michitaka Tsuzuki, Tatsuaki Matsubara, Ichiro Manabe, Masataka Sata, Ryozo Nagai, Toyoaki Murohara (2007)  Angiotensin II receptor blocker inhibits neointimal hyperplasia through regulation of smooth muscle-like progenitor cells.   Arterioscler Thromb Vasc Biol 27: 11. 2363-2369 Nov  
Abstract: OBJECTIVES: Angiotensin II (ATII) type 1 receptor (AT1R) blocker (ARB) has been shown to inhibit neointimal formation. Bone marrow-derived mononuclear cells (BM-MNCs) give rise to smooth muscle (SM)-like cells at injured arterial wall and contribute to neointimal formation. However, role of the renin-angiotensin system in the homing process of SM-like cells during neointimal formation is unknown. MATERIAL AND METHODS: When human BM-MNCs and peripheral blood MNCs (PB-MNCs) were cultured under treatment with PDGF-BB and bFGF, these cells gave rise to SM-like cells with expression of alphaSMA, SMemb, and SM1 proteins. RT-PCR showed the expression of AT1R, ATII type 2 receptor (AT2R), alphaSMA, and SMemb mRNAs. ATII accelerated the differentiation of SM-like cells, which was inhibited by an ARB CV11974 (P<0.05). We then examined the effects of ATII, CV11974, and AT2R antagonist PD123319 on neointimal formation and BM-derived SM-like cell incorporation at injured arteries in vivo. BM from green fluorescence protein (GFP)-transgenic mice was transplanted to irradiated WT mice. GFP-BM chimera mice were subjected to wire injury on the left femoral artery. ATII (100 ng/kg/min) stimulated whereas CV11974 (1 mg/kg/d) inhibited neointimal formation. Number of GFP+ alphaSMA+ cells at neointima correlated with the intima/media ratio (r=0.69, P<0.05). CONCLUSION: BM-derived SM-like progenitor cells contributed to the neointimal formation after arterial injury. ATII accelerated whereas ARB suppressed this process. These are new aspects of the ARB-mediated inhibition of atherosclerotic disease progression.
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2006
 
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Tetsuya Amano, Tatsuaki Matsubara, Hideo Izawa, Masayuki Torigoe, Tomohiro Yoshida, Yukihisa Hamaguchi, Hideki Ishii, Manabu Miura, Yuzo Hayashi, Yasuhiro Ogawa, Toyoaki Murohara (2006)  Impact of plasma aldosterone levels for prediction of in-stent restenosis.   Am J Cardiol 97: 6. 785-788 Mar  
Abstract: Aldosterone promotes vascular smooth muscle cell proliferation and endothelial dysfunction, suggesting the contribution to in-stent restenosis (ISR). This study evaluated any relation between plasma aldosterone levels and ISR 6 months after successful coronary stenting. We enrolled 156 consecutive patients with stable angina who underwent coronary bare metal stenting. Plasma aldosterone levels and other serum markers known to influence cardiovascular events were measured in all patients at baseline. Patients with restenosis were found to have significantly higher plasma aldosterone levels than their counterparts without restenosis (162 +/- 60 vs 122 +/- 60 pg/ml, p = 0.007). On logistic regression analysis, even after adjusting for clinical, angiographic, and other confounding variables, plasma aldosterone level per 10 pg/ml (odds ratio 1.34, 95% confidence interval 1.10 to 1.63, p = 0.006) proved to be the independent predictor of ISR. The area under the receiver-operating characteristic curve for plasma aldosterone level was 0.75, and the optimal cut-off value identified by receiver-operating characteristic analysis was 141.9 pg/ml, which had a predictive accuracy of 69%. In conclusion, the present findings indicate that plasma aldosterone levels at baseline are independent predictors of ISR and may constitute a potential therapeutic target.
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Takumi Yamada, Yoshimasa Murakami, Taro Okada, Mitsuhiro Okamoto, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Teruo Ito, Masahiro Muto, Takahisa Kondo, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2006)  Electrophysiological pulmonary vein antrum isolation with a multielectrode basket catheter is feasible and effective for curing paroxysmal atrial fibrillation: efficacy of minimally extensive pulmonary vein isolation.   Heart Rhythm 3: 4. 377-384 Apr  
Abstract: BACKGROUND: How extensive should an appropriate pulmonary vein (PV) ablation be is a matter of controversy. OBJECTIVE: The study's aim was to investigate the efficacy of minimally extensive PV ablation for isolating the PV antrum (PVA) with the guidance of electrophysiological parameters. METHODS: Fifty-five consecutive symptomatic paroxysmal atrial fibrillation (PAF) patients underwent PV mapping with a multielectrode basket catheter (MBC). A 31-mm MBC was deployed in 3-4 PVs as proximally as possible without dislodgement, and the longitudinal PV mapping enabled us to recognize single sharp potentials formed by the total fusion of the PV and left atrial potentials around the PV ostium or the transverse activation patterns that were observed. Those potentials were defined as PVA potentials. Radiofrequency ablation was performed circumferentially targeting PVA potentials with the end point being their elimination. RESULTS: After circumferential PVA ablation, electrical disconnection was achieved in 77% and residual PVA conduction gaps were observed in 23% of all targeted PVs. Those residual conduction gaps were mainly located at the border between ipsilateral PVs (42%) and between the left PVs and left atrial appendage (33%) and were eliminated by a mean of 3 +/- 2 minutes of local radiofrequency deliveries. During the follow-up period (11 +/- 5 months), 46 (84%) patients were free of symptomatic PAF without any anti-arrhythmic drugs. No PV stenosis or spontaneous left atrial flutter occurred. CONCLUSIONS: Electrophysiological PVA ablation with an MBC is feasible and effective for curing PAF because this minimally extensive PVA isolation technique targets the optimal sites, achieving both high efficacy and safety.
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Toru Asai, Kenji Okumura, Ryotaro Takahashi, Hideo Matsui, Yasushi Numaguchi, Hisashi Murakami, Ryuichiro Murakami, Toyoaki Murohara (2006)  Combined therapy with PPARalpha agonist and L-carnitine rescues lipotoxic cardiomyopathy due to systemic carnitine deficiency.   Cardiovasc Res 70: 3. 566-577 Jun  
Abstract: OBJECTIVE: Peroxisome proliferator-activated receptors (PPAR) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily and are key regulators of fatty acid oxidation (FAO) in the heart. Systemic carnitine deficiency (SCD) causes disorders of FAO and induces hypertrophic cardiomyopathy with lipid accumulation. We hypothesized that activation of PPARalpha by fenofibrate, a PPARalpha agonist, in addition to conventional L-carnitine supplementation may exert beneficial effects on the lipotoxic cardiomyopathy in juvenile visceral steatosis (JVS) mouse, a murine model of SCD. METHODS: Both wild-type (WT) and JVS mice were fed a normal chow, 0.2% fenofibrate containing chow (FE), a 0.1% L-carnitine containing chow (CA) or a 0.1% L-carnitine + 0.2% fenofibrate containing chow (CA + FE) from 4 weeks of age. Four to 8 animals per group were used for each experiment and 9 to 11 animals per group were used for survival analysis. RESULTS: At 8 weeks of age, JVS mice exhibited marked ventricular hypertrophy, which was more attenuated by CA + FE than by CA or FE alone. CA + FE markedly reduced the high plasma and myocardial triglyceride levels and increased the low myocardial ATP content to control levels in JVS mice. In JVS mice, myocardial 1,2-diacylglycerol (DAG) was significantly increased and showed a distinct fatty acid composition with elevation of 18:1(n-7,9) and 18:2(n-6) fatty acids compared with that in WT mice. CA + FE significantly altered the fatty acid composition of DAG and inhibited the membrane translocation of cardiac protein kinase C beta2 in JVS mice. Furthermore, CA + FE prevented the progressive left ventricular dysfunction and dramatically improved the survival rate in JVS mice (survival rate at 400 days after birth: 89 vs. 0%, P < 0.0001). CONCLUSIONS: PPARalpha activation, in addition to l-carnitine supplementation, may rescue the detrimental lipotoxic cardiomyopathy in SCD by improving cardiac energy and lipid metabolism as well as systemic lipid metabolism.
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Akiko Imamura, Kenji Okumura, Yasuhiro Ogawa, Ryuichiro Murakami, Masayuki Torigoe, Yasushi Numaguchi, Toyoaki Murohara (2006)  Klotho gene polymorphism may be a genetic risk factor for atherosclerotic coronary artery disease but not for vasospastic angina in Japanese.   Clin Chim Acta 371: 1-2. 66-70 Sep  
Abstract: BACKGROUND: The klotho gene, originally identified by insertional mutagenesis in mice, suppresses multiple aging phenotypes, including atherosclerosis. We tested the hypothesis that the G-395A polymorphism of the klotho gene is associated with increased risk for 2 types of ischemic heart disease in Japanese. METHODS: The study population consisted of 197 patients with coronary heart disease (CAD) who had >75% luminal diameter narrowing, 77 patients with vasospastic angina (VSA) without significant fixed coronary artery disease, and 331 healthy control subjects. RESULTS: The frequency of the A allele carriers of the klotho gene was significantly higher in the CAD group than in the control group (29.9% vs. 19.0%). The unadjusted odds ratio for CAD in the A allele carriers compared with the control group was 1.82 (p=0.004) and a traditional risk-adjusted logistic regression model revealed that the A allele was an independent predictor of CAD (odds ratio, 1.76; p=0.03). In contrast, the frequency of the A allele carriers was not significantly different in the VSA group (23.4%; adjusted odds ratio, 1.18. CONCLUSIONS: The -395A polymorphism of the human klotho gene may be a genetic risk factor for IHD and not for VSA.
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Koichi Kobayashi, Takahisa Kondo, Natsuo Inoue, Mika Aoki, Masaaki Mizuno, Kimihiro Komori, Jun Yoshida, Toyoaki Murohara (2006)  Combination of in vivo angiopoietin-1 gene transfer and autologous bone marrow cell implantation for functional therapeutic angiogenesis.   Arterioscler Thromb Vasc Biol 26: 7. 1465-1472 Jul  
Abstract: OBJECTIVE: Autologous bone marrow mononuclear cell (BM-MNC) implantation into ischemic tissues promotes angiogenesis, but a large amount of marrow aspiration is required, which is a major clinical limitation. Angiopoietin-1 (Ang-1) is requisite for vascular maturation during angiogenesis. We examined the impacts of combinatorial Ang-1 gene transfer and low-dose autologous BM-MNC implantation on therapeutic angiogenesis in a rabbit model of hind limb ischemia. METHODS AND RESULTS: Rabbits were divided into 4 groups: phosphate-buffered saline (control), 500 microg Ang-1 plasmid (Ang-1), 1 x 10(6) autologous BM-MNCs (BMC), and Ang-1 plasmid plus BM-MNCs (combination). The Ang-1 group had a greater angiographic score and capillary density compared with the control (P<0.05), but the Ang-1 gene therapy alone did not improve transcutaneous oxygen pressure (TcO2) and skin ulcer score. However, the combination group showed a significant improvement in not only angiographic score and capillary density (P<0.05) but also TcO2 (P<0.05) and skin ulcer score. These efficacies were greater in the combination group compared with the BMC group. CONCLUSIONS: This Ang-1 gene and BM-MNC combination therapy enhances not only quantitative but also qualitative angiogenesis in ischemic tissues. Moreover, the combination therapy will enable a reduction in the amount of BM aspiration required for significant therapeutic angiogenesis.
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Takumi Yamada, Yoshimasa Murakami, Taro Okada, Mitsuhiro Okamoto, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Teruo Ito, Masahiro Muto, Takahisa Kondo, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2006)  Can segmental pulmonary vein ablation reduce the recurrence of atrial fibrillation when using a higher RF power, larger tip electrode catheter, and additional RF deliveries?: the limitations of point-by-point RF ablation.   Int Heart J 47: 2. 219-228 Mar  
Abstract: The aim of this study was to investigate whether segmental ostial catheter ablation (SOCA) designed to prevent the electrical connections (ECs) between the left atrium and pulmonary veins (PVs) might help increase the efficacy of SOCA in paroxysmal atrial fibrillation (PAF). PV mapping and successful SOCA were performed with a basket catheter in 108 consecutive patients with PAF. Radiofrequency energy was delivered using a maximum output of 30 W with a 4 mm tip catheter (group I; 47) or 40 W with an 8 mm tip catheter (group II; 61). Only in the group II patients were additional radiofrequency deliveries to the specific sites where the ECs tended to recover performed after successful SOCA. After the first procedure, PAF recurred in 47% of the group I patients and 32% of the group II patients. In all 27 patients who underwent repeat procedures, EC recoveries were observed more frequently in group I than in group II (69% versus 49%; P < 0.05). After multiple procedures, there was more freedom from PAF in group II (84%) than in group I (66%) (P < 0.05). SOCA with a higher RF power, larger tip catheter, and additional RF deliveries could achieve a more effective SOCA.
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Kimiyasu Egami, Toyoaki Murohara, Mika Aoki, Toyojiro Matsuishi (2006)  Ischemia-induced angiogenesis: role of inflammatory response mediated by P-selectin.   J Leukoc Biol 79: 5. 971-976 May  
Abstract: P-selectin is a 140-kDa glycoprotein expressed on endothelial cells and platelets. P-selectin mediates the tethering and rolling of leukocytes along the endothelium, an early step of leukocyte extravasation. Although inflammation is a requisite process for ischemia-induced angiogenesis, little is known regarding the role of P-selectin in angiogenesis in the setting of tissue ischemia. We examined whether ischemia-induced angiogenesis is altered in P-selectin knockout (P-selectin(-/-)) mice. Angiogenesis was evaluated in a surgically induced hind-limb ischemia model using laser Doppler blood flowmetry (LDBF) and histological capillary density (CD). After left hind-limb ischemia, the ischemic/normal limb LDBF ratio was persistently lower in P-selectin(-/-) mice compared with wild-type (WT) mice. CD was also significantly lower in P-selectin(-/-) mice than in WT mice on Postoperative Day 14. Fewer numbers of total CD45+ inflammatory leukocytes infiltrated into the ischemic tissues in P-selectin(-/-) mice than in WT mice, and immunohistochemical analysis revealed the number of infiltrated leukocytes expressing vascular endothelial growth factor was also decreased in P-selectin(-/-) mice. P-selectin mRNA expression was augmented after hind-limb ischemia in WT mice. In conclusion, P-selectin may play an important role in ischemia-induced angiogenesis by promoting early inflammatory mononuclear cell infiltration. P-selectin would become one possible target molecule for modulating inflammatory angiogenesis.
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Takumi Yamada, Yoshimasa Murakami, Taro Okada, Mitsuhiro Okamoto, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Teruo Ito, Masahiro Muto, Takahisa Kondo, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2006)  Incidence, location, and cause of recovery of electrical connections between the pulmonary veins and the left atrium after pulmonary vein isolation.   Europace 8: 3. 182-188 Mar  
Abstract: AIMS: The aim of this study was to reveal the incidence, location, and cause of recovery of the electrical connections (ECs) between the left atrium and the pulmonary veins (PVs) after the segmental ostial PV isolation (PVI). METHODS AND RESULTS: Pulmonary vein mapping and successful PVI were performed using a computerized three-dimensional mapping system (QMS2trade mark) with a basket catheter in 167 PVs in 53 consecutive patients with atrial fibrillation (AF). In 14 patients with recurrent AF after PVI, the same PV mapping and isolation as in the first procedure were performed, and the PV potential maps constructed by QMS2 in two different procedures were compared. Forty-nine recovered ECs were observed in 27 PVs, and all were eliminated by a few local radiofrequency (RF) applications. Thirty-four (69%) of those ECs recovered at the edge of original ECs, and another 15 (31%) recovered at the mid-portion of the continuous broad original ECs. CONCLUSION: Electrical connection recovery occurred most commonly at the edges of original ECs and occasionally at the mid-portion of continuous broad original ECs after PVI probably due to tissue oedema neighbouring the segmental RF lesions. Further RF lesions at the edge of original ECs and linear ablation to the continuous broad ECs may help reduce AF recurrence.
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Kohzo Nagata, Koji Obata, Jinglan Xu, Sahoko Ichihara, Akiko Noda, Hirotaka Kimata, Tomoko Kato, Hideo Izawa, Toyoaki Murohara, Mitsuhiro Yokota (2006)  Mineralocorticoid receptor antagonism attenuates cardiac hypertrophy and failure in low-aldosterone hypertensive rats.   Hypertension 47: 4. 656-664 Apr  
Abstract: Chronic elevation of plasma aldosterone contributes to heart failure. Mineralocorticoid receptor (MR) antagonism is cardioprotective in such a setting, but whether such protection occurs in the presence of low-aldosterone concentrations remains unclear. We investigated whether MR blockade attenuates cardiac hypertrophy and failure in rats with salt-sensitive hypertension. Dahl salt-sensitive (DS) rats fed a high-salt diet from 7 weeks develop concentric left ventricular (LV) hypertrophy secondary to hypertension at 12 weeks followed by heart failure at 19 weeks (DS-CHF). DS rats on such a diet were treated with a non-antihypertensive dose of the selective MR antagonist eplerenone from 12 to 19 weeks. Renin activity and aldosterone concentration in plasma were decreased in DS-CHF rats compared with controls. LV hypertrophy and fibrosis, as well as macrophage infiltration around coronary vessels, were apparent in DS-CHF rats. The amounts of mRNAs for 11beta-hydroxysteroid dehydrogenase type 1, MR, monocyte chemoattractant protein 1, and osteopontin were increased in these hearts. Treatment of DS-CHF rats with eplerenone inhibited these changes in gene expression, as well as coronary vascular inflammation and heart failure. Eplerenone attenuated both the decrease in the ratio of reduced to oxidized glutathione and the increase in NADPH oxidase activity apparent in DS-CHF rat hearts. MR blockade with eplerenone thus resulted in attenuation of LV hypertrophy and failure, without an antihypertensive effect, in rats with low-aldosterone hypertension. The beneficial cardiac effects of eplerenone are likely attributable, at least in part, to attenuation of myocardial oxidative stress and coronary vascular inflammation induced by glucocorticoid-activated MRs.
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Akihiro Hirashiki, Hideo Izawa, Fuji Somura, Koji Obata, Tomoko Kato, Takao Nishizawa, Akira Yamada, Hiroyuki Asano, Satoru Ohshima, Akiko Noda, Shigeo Iino, Kohzo Nagata, Kenji Okumura, Toyoaki Murohara, Mitsuhiro Yokota (2006)  Prognostic value of pacing-induced mechanical alternans in patients with mild-to-moderate idiopathic dilated cardiomyopathy in sinus rhythm.   J Am Coll Cardiol 47: 7. 1382-1389 Apr  
Abstract: OBJECTIVES: The relation between the occurrence of pacing-induced mechanical alternans and prognosis in patients with mild-to-moderate idiopathic dilated cardiomyopathy (IDCM) in sinus rhythm was investigated prospectively. The myocardial expression of genes for Ca2+-handling proteins in such patients was also examined. BACKGROUND: Mechanical alternans occurs in some patients with severe heart failure, but the relation between the occurrence of mechanical alternans and prognosis in patients with IDCM has remained unknown. METHODS: Left ventricular (LV) pressure was measured during atrial pacing, and LV endomyocardial biopsy specimens were collected in 36 IDCM patients and 8 controls. Idiopathic dilated cardiomyopathy patients were divided into two groups consisting of 22 individuals who did not develop mechanical alternans at heart rates up to 140 beats/min (group A) and of 14 individuals who did (group B). The patients were followed up for a mean of 3.7 years. RESULTS: There was no significant difference in LV ejection fraction or the plasma concentration of brain natriuretic peptide between groups A and B. The myocardial abundance of ryanodine receptor 2 messenger ribonucleic acid (mRNA) was significantly lower in groups A and B than in controls, whereas that of sarcoplasmic reticulum Ca2+-ATPase mRNA was significantly lower in group B than in group A or controls. Stepwise multivariate analysis identified pacing-induced mechanical alternans as the strongest predictor of cardiac events. Event-free survival in group A was significantly greater than that in group B. CONCLUSIONS: The occurrence of pacing-induced mechanical alternans is a potentially useful indicator of poor prognosis in patients with mild-to-moderate IDCM in sinus rhythm.
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Kunihiro Matsushita, Hiroshi Yatsuya, Koji Tamakoshi, Keiko Wada, Rei Otsuka, Huiming Zhang, Kaichiro Sugiura, Takahisa Kondo, Toyoaki Murohara, Hideaki Toyoshima (2006)  Inverse association between adiponectin and C-reactive protein in substantially healthy Japanese men.   Atherosclerosis 188: 1. 184-189 Sep  
Abstract: OBJECTIVE: An inverse association between adiponectin and C-reactive protein (CRP) has been shown in certain pathological states including obesity, diabetes, and coronary artery disease, which themselves might have confounded this association. This study investigated the association between adiponectin and CRP among substantially healthy subjects. METHODS AND RESULTS: A population of 2347 middle-aged Japanese men with no medical history of cardiovascular disease, cancer, diabetes, hypertension, or hyperlipidemia was evaluated. Those with some metabolic syndrome components from serological and anthropometric tests were excluded, leaving 714 men for analysis. Serum adiponectin and CRP were significantly correlated (r = -0.21, P < 0.001). After categorization into quartiles from the lowest to the highest adiponectin concentration (Q1 to Q4), the CRP level was found to be significantly higher in Q1 than in Q2, Q3 and Q4 (0.41 mg/L versus 0.30, 0.25 and 0.24 mg/L, P = 0.043, P < 0.001 and P < 0.001, respectively). These associations remained significant even after adjustment for covariates. Moreover, multiple linear regression analysis revealed that adiponectin contributed more strongly to CRP than other factors, including the index of insulin resistance. CONCLUSIONS: An inverse and strong association between adiponectin and CRP in substantially healthy subjects implies that decreased serum adiponectin might be fundamentally associated with the early stage of low-grade inflammation.
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Xian Wu Cheng, Masafumi Kuzuya, Kae Nakamura, Qun Di, Zexuan Liu, Takeshi Sasaki, Shigeru Kanda, Hai Jin, Guo-Ping Shi, Toyoaki Murohara, Mitsuhiro Yokota, Akihisa Iguchi (2006)  Localization of cysteine protease, cathepsin S, to the surface of vascular smooth muscle cells by association with integrin alphanubeta3.   Am J Pathol 168: 2. 685-694 Feb  
Abstract: Smooth muscle cell (SMC) migration from the tunica media to the intima, a key event in neointimal formation, requires proteolytic degradation of elastin-rich extracellular matrix barriers. Although cathepsin S (Cat S) is overexpressed in atherosclerotic and neointimal lesions, its exact role in SMC behavior remains primarily unresolved. We examined the involvement of Cat S on SMC migration through an extracellular matrix barrier and its localization in SMCs. A selective Cat S inhibitor and the endogenous inhibitor cystatin C significantly attenuated SMC invasion across elastin gel. Western blotting and cell surface biotinylation analysis demonstrated localization of the 28-kd active form of Cat S on the SMC surface, consistent with its role in the proteolysis of subcellular matrices. Treatment with interferon-gamma or interleukin-beta1 significantly augmented the ability of SMC membranes to degrade elastin along with a significant increase in the level of active Cat S compared with controls. Immunofluorescence and confocal microscopy showed a punctuated pattern of Cat S clusters at the periphery of SMCs; further studies demonstrated partial co-localization of Cat S and integrin alphanubeta3 at the cell surfaces. These findings demonstrate that active Cat S co-localizes with integrin alphanubeta3 as a receptor on the SMC surface, playing an important role in the invasive behavior of SMCs.
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M Hayashi, T Matsushita, N Mackman, M Ito, T Adachi, A Katsumi, K Yamamoto, K Takeshita, T Kojima, H Saito, T Murohara, T Naoe (2006)  Fatal thrombosis of antithrombin-deficient mice is rescued differently in the heart and liver by intercrossing with low tissue factor mice.   J Thromb Haemost 4: 1. 177-185 Jan  
Abstract: BACKGROUND: We previously reported that the targeted disruption of murine antithrombin (AT) gene resulted in embryonic lethality before 16.5 gestational days (gd) because of severe cardiac and hepatic thrombosis. OBJECTIVE AND METHODS: To investigate the influences of lowered tissue factor (TF) activity upon hypercoagulation of AT-/- embryos, we crossed AT+/- with low TF (mTF-/- hTF+) mice to yield homozygous AT-deficient mice with the extremely low TF activity, that is expressed from the inserted human TF mini gene. RESULTS: AT-/- embryos either with 50% TF (AT-/- mTF+/- hTF+) or with low (approximately 1% TF, AT-/- mTF-/- hTF+) were not born, although the survival was prolonged until 18.5 gd. In both genotypes, histological examination showed disseminated thrombosis in hepatic sinusoidal space or in the portal veins, suggesting that the thrombogenesis caused loss of hepatic blood flow. As in original AT-/-, AT-/- mTF+/- hTF+ showed subcutaneous (s.c.) bleeding and also suffered from the myocardial degeneration apparently because of coronary thrombus formation. However, AT-/- mTF-/- hTF+ had no skin hemorrhage and the thrombosis and degeneration were completely abolished in the heart. Myocardium of adult low TF mice had exhibited fibrosis secondary to hemorrhage; however, it was significantly decreased in low TF mice with AT+/-. CONCLUSIONS: Our current model suggests that, in the heart, TF plays an important role in the thrombogenesis and it counterbalances AT-dependent anticoagulation. AT may be a potent anticoagulant during mice development and the activation and subsequent regulation of TF-procoagulant activity take place differently between the liver and the heart. These differences appear to point to local regulatory mechanisms in murine hemostasis.
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Takumi Yamada, Yoshimasa Murakami, Taro Okada, Mitsuhiro Okamoto, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Teruo Ito, Masahiro Muto, Takahisa Kondo, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2006)  Usefulness of esophageal leads for determining the strategy of pulmonary vein ablation to avoid complications associated with the esophagus.   Am J Cardiol 97: 10. 1494-1497 May  
Abstract: To avoid fatal complications after extensive pulmonary vein (PV) ablation, it has been proved important to comprehend the anatomic relation between the PVs and the esophagus. In 42 consecutive patients with atrial fibrillation, PV ostial isolation was performed using a basket catheter. The shortest distance and anatomic relation between the esophageal lead and PV ostium, determined by successful PV ostial isolation, was analyzed in biplane fluoroscopic views. In 18 left superior PVs (LSPVs) (43%), 13 left inferior PVs (32%) (LIPVs), and all the right PVs (group A), the shortest distance was > 10 mm in > or = 1 of the biplane fluoroscopic views. In 4 LSPVs (10%) and 2 LIPVs (5%) (group B), the shortest distance was < or = 5 mm in the fluoroscopic views. In the remaining PVs (group C), the esophagus was situated directly behind 10 LSPVs (24%) and 12 LIPVs (29%) (group C1), posteromedial to 1 LSPV (2%) and 9 LIPVs (22%) (group C2), and medial to 9 LSPVs (21%) and 5 LIPVs (12%) (group C3). The risk of esophagus-associated complications with ablation around the left PV ostia was suggested to be high in group B, very low in group A, and relatively low in group C. In group C3, extensive PV ablation might increase the risk of that complication. In conclusion, esophageal leads are useful for determining strategies for PV ablation to avoid esophagus-associated complications, because they enable comprehension of the anatomic relation between the PVs and the esophagus.
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Shin-Ichiro Yokoyama, Noboru Fukuda, Yuxin Li, Kazuhiro Hagikura, Tadateru Takayama, Satoshi Kunimoto, Junko Honye, Satoshi Saito, Mika Wada, Aya Satomi, Maiko Kato, Hideo Mugishima, Yoshiaki Kusumi, Masako Mitsumata, Toyoaki Murohara (2006)  A strategy of retrograde injection of bone marrow mononuclear cells into the myocardium for the treatment of ischemic heart disease.   J Mol Cell Cardiol 40: 1. 24-34 Jan  
Abstract: OBJECTIVE: Bone marrow cells implantation (BMI) has been reported to efficiently improve ischemic heart disease. However, BMI strategies are generally invasive. To establish a BMI strategy for ischemic heart disease, we performed implantation of autologous cryopreserved mononuclear cells (MNCs) from bone marrow (BM) retrogradely into the myocardium via the coronary vein in pigs with acute myocardial infarction (AMI) and old myocardial infarction (OMI). METHODS: BM cells were harvested from the pigs' fumurs. MNCs were collected by centrifugation and were cryopreserved. Anterior myocardial infarction was induced by occlusion of the midportion of the left anterior descending coronary artery without surgical intervention. Frozen BM cells were quickly thawed and injected retrogradely via the coronary vein into the myocardium through a single balloon infusion catheter 6 h and 2 weeks after the induction of infarction. Four weeks after implantation, coronary arteriograms were obtained, cardiac function was analyzed with the use of a conductance catheter, and histopathologic analysis was performed with a confocal laser microscope. Plasma levels of natriuretic peptides and angiogenic growth factors were measured after BMI. RESULTS: Flow cytometric analysis revealed that 90% of cryopreserved BM cells were viable in vitro. Labeled BM cells were entirely distributed around in the infarcted area of maycardium in pigs. BMI increased collateral neovascuralization in infarcted hearts. BMI significantly improved cardiac function in AMI with BMI and OMI with BMI groups. BMI also increased the formation of microcapillary arteries in infarcted hearts. Levels of natriuretic peptides were significantly decreased, and levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF2) were significantly increased after BMI. Confocal laser microscopy revealed the presence of proliferative and activated myocardial cells in infarcted hearts after BMI. CONCLUSION: The retrograde infusion of cryopreserved BM cells into myocardium efficiently induced angiogenesis and improved cardiac function in pigs with AMI or OMI. These results suggest that the present strategy of BMI will be safe and feasible as an angiogenic cell therapy for ischemic heart disease.
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Hisashi Murakami, Ryuichiro Murakami, Fukushi Kambe, Xia Cao, Ryotaro Takahashi, Toru Asai, Toshihisa Hirai, Yasushi Numaguchi, Kenji Okumura, Hisao Seo, Toyoaki Murohara (2006)  Fenofibrate activates AMPK and increases eNOS phosphorylation in HUVEC.   Biochem Biophys Res Commun 341: 4. 973-978 Mar  
Abstract: Fenofibrate improves endothelial function by lipid-lowering and anti-inflammatory effects. Additionally, fenofibrate has been demonstrated to upregulate endothelial nitric oxide synthase (eNOS). AMP-activated protein kinase (AMPK) has been reported to phosphorylate eNOS at Ser-1177 and stimulate vascular endothelium-derived nitric oxide (NO) production. We report here that fenofibrate activates AMPK and increases eNOS phosphorylation and NO production in human umbilical vein endothelial cells (HUVEC). Incubation of HUVEC with fenofibrate increased the phosphorylation of AMPK and acetyl-CoA carboxylase. Fenofibrate simultaneously increased eNOS phosphorylation and NO production. Inhibitors of protein kinase A and phosphatidylinositol 3-kinase failed to suppress the fenofibrate-induced eNOS phosphorylation. Neither bezafibrate nor WY-14643 activated AMPK in HUVEC. Furthermore, fenofibrate activated AMPK without requiring any transcriptional activities. These results indicate that fenofibrate stimulates eNOS phosphorylation and NO production through AMPK activation, which is suggested to be a novel characteristic of this agonist and unrelated to its effects on peroxisome proliferator-activated receptor alpha.
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Hideki Ishii, Satoshi Ichimiya, Masaaki Kanashiro, Tetsuya Amano, Tatsuaki Matsubara, Toyoaki Murohara (2006)  Effects of intravenous nicorandil before reperfusion for acute myocardial infarction in patients with stress hyperglycemia.   Diabetes Care 29: 2. 202-206 Feb  
Abstract: OBJECTIVE: Stress hyperglycemia increases the risk of mortality and poor outcomes in patients with acute myocardial infarction (AMI). We aimed to assess effects of intravenous nicorandil administered before reperfusion on AMI patients with stress hyperglycemia. RESEARCH DESIGN AND METHODS: This study consisted of 158 consecutive first AMI patients with stress hyperglycemia who underwent percutaneous coronary intervention (PCI) within 24 h from the onset. They were randomly assigned to receive 12 mg of nicorandil (n = 81) or a placebo (n = 77) intravenously just before reperfusion. Stress hyperglycemia was defined as a blood glucose level > or =10 mmol/l (180 mg/dl). We examined various aspects of epicardial flow and microvascular function as immediate data and major adverse cardiac events (MACEs) (coronary heart disease death or unplanned readmission due to congestive heart failure) as late-phase data. RESULTS: The incidence of slow flow after PCI was lower in the nicorandil group (13.6 vs. 27.3%, P < 0.04). ST segment resolution >50% was observed in 70.4 and 53.2% on nicorandil and placebo, respectively (P < 0.03). Patients treated with nicorandil had a lower peak creatine kinase level (3,137 +/- 2,577 vs. 4,333 +/- 3,608, P < 0.02). Upon Kaplan-Meier analysis, 5 years' freedom from MACEs was 86.4% in the nicorandil group and 74.0% in the placebo (P < 0.05). CONCLUSIONS: Adjunctive therapy with administration of intravenous nicorandil before reperfusion on AMI patients with stress hyperglycemia significantly improves epicardial flow and prevents the occurrence of severe microvascular reperfusion injury, resulting in better outcomes in these patients.
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Hisashi Umeda, Toshiaki Katoh, Mitsunori Iwase, Hideo Izawa, Kohzo Nagata, Kosuke Watanabe, Taro Okada, Takumi Yamada, Tomomitsu Tani, Toyoaki Matsushita, Yoshimasa Murakami, Mitsuhiro Okamoto, Takeshi Shimizu, Toyoaki Murohara, Mitsuhiro Yokota (2006)  The distal protection during primary percutaneous coronary intervention alleviates the adverse effects of large thrombus burden on myocardial reperfusion.   Circ J 70: 3. 232-238 Mar  
Abstract: BACKGROUND: The presence of intracoronary large thrombus burden (LTB) in the infarct-related artery increases the risk of distal embolization and no-reflow during percutaneous coronary intervention (PCI). Evaluation of whether the distal protection (DP) during primary PCI reduces adverse effects of LTB on myocardial reperfusion and infarct size was investigated. METHODS AND RESULTS: A consecutive series of 88 patients with acute myocardial infarction undergoing primary PCI using DP were compared with 81 consecutive patients treated by primary PCI alone. The DP use showed similar post-procedural myocardial blush grade (MBG)-3 and infarct size, but improved corrected thrombolysis in myocardial infarction frame count (cTFC) (29+/-11 vs 35+/-20, p=0.011) and the incidence of ST-segment resolution (80.7% vs 66.7%, p=0.038). In patients with LTB present, however, the DP use reduced occurrences of no-reflow (0% vs 11.8%, p=0.036) and distal embolization (4.8% vs 17.6%, p=0.129), resulting in higher occurrences of MBG-3 (61.9% vs 35.3%, p=0.021) and ST-segment resolution (78.6% vs 50.0%, p=0.009), lower cTFC values (30+/-8 vs 40+/-22, p=0.012) and smaller infarct size (12.2+/-11.2 vs 18.7+/-11.1, p=0.015). CONCLUSIONS: With an improved myocardial reperfusion and smaller infarct size in patients with LTB, the DP during primary PCI might be a better strategy in this particular setting compared with conventional strategy.
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Takumi Yamada, Yoshimasa Murakami, Taro Okada, Toyoaki Murohara (2006)  Focal atrial fibrillation associated with multiple breakout sites at the crista terminalis.   Pacing Clin Electrophysiol 29: 2. 207-210 Feb  
Abstract: A 34-year-old man with permanent atrial fibrillation (AF) underwent electrophysiologic testing. Spontaneous AF was observed even after successful pulmonary vein (PV) isolation of all four PVs. Intracardiac electrograms recorded from a basket catheter deployed around the crista terminalis during triggered atrial premature beats exhibited low-amplitude potentials which were suggested to reflect focal ectopic activity, preceding high-frequency atrial potentials. The firing from those focal activity sites induced a shift in the breakout sites and conduction block to the right atrium, which suggested the participation of preferential conduction. Radiofrequency catheter ablation targeting the focal origin and preferential conduction sites eliminated the AF.
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Eitaro Taniguchi, Motoaki Kin, Takuji Torimura, Toru Nakamura, Hiroto Kumemura, Shinichiro Hanada, Takao Hisamoto, Takafumi Yoshida, Takumi Kawaguchi, Shinji Baba, Michiko Maeyama, Hironori Koga, Masaru Harada, Ryukichi Kumashiro, Takato Ueno, Shinya Mizuno, Hisao Ikeda, Tsutomu Imaizumi, Toyoaki Murohara, Michio Sata (2006)  Endothelial progenitor cell transplantation improves the survival following liver injury in mice.   Gastroenterology 130: 2. 521-531 Feb  
Abstract: BACKGROUND & AIMS: Neovascularization, which is vital to the healing of injured tissues, recently has been found to include both angiogenesis, which involves in mature endothelial cells, and vasculogenesis, involving endothelial progenitor cells. The aim of this study was to clarify the possible roles of endothelial progenitor cells during postnatal liver regeneration. METHODS: To determine how endothelial progenitor cells participate in liver regeneration, human or mouse endothelial progenitor cells were transplanted into the mice with carbon tetrachloride-induced acute liver injury. Survival rate of the mice in endothelial progenitor cell-transplanted and control groups was calculated. Separately, livers removed temporally from both groups were examined. RESULTS: At an early stage, transplanted human endothelial progenitor cells were seen mainly surrounding hepatic central veins where hepatocytes showed extensive necrosis; later, the transplanted cells formed tubular structures. More of these cells were observed along hepatic sinusoids. Transplantation of human or mouse endothelial progenitor cells improved survival of the mice following liver injury (from 28.6% to 85.7%, P < .0005 and from 33.3% to 80.0%, P < .001, respectively), accompanied by greater proliferation of hepatocytes. Human endothelial progenitor cells produced several growth factors, such as hepatocyte growth factor, transforming growth factor-alpha, heparin-binding epidermal growth factor-like growth factor, and vascular endothelial growth factor, and also elicited endogenous growth factors. CONCLUSIONS: Endogenous and exogenous growth factors and direct neovascularization after endothelial progenitor cell transplantation promoted liver regeneration, thus improving survival after liver injury. Transplantation of endothelial progenitor cells could represent a new therapeutic strategy for promoting liver regeneration.
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Kunihiro Matsushita, Hiroshi Yatsuya, Koji Tamakoshi, Keiko Wada, Rei Otsuka, Seiko Takefuji, Kaichiro Sugiura, Takahisa Kondo, Toyoaki Murohara, Hideaki Toyoshima (2006)  Comparison of circulating adiponectin and proinflammatory markers regarding their association with metabolic syndrome in Japanese men.   Arterioscler Thromb Vasc Biol 26: 4. 871-876 Apr  
Abstract: BACKGROUND: Anti-inflammatory and proinflammatory molecules purportedly play an important role in developing metabolic syndrome (MetS). However, little is known as to the relative importance of these molecules in the association with MetS. METHODS AND RESULTS: We studied 624 middle-aged Japanese men without medical history of cardiovascular disease or cancer and investigated the associations of circulating tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), C-reactive protein (CRP), and adiponectin with MetS. We used the respective definitions proposed by the National Cholesterol Education Program Adult Treatment Panel III (ATP-III), the International Diabetes Federation, and the Japanese Society of Internal Medicine. Decreased serum adiponectin was observed in those with any of the ATP-III-MetS components, whereas this was not the case with increased TNF-alpha, IL-6, or CRP. Adiponectin and CRP levels linearly deteriorated with an increasing number of ATP-III-MetS components (trend P<0.001, respectively). Significantly higher CRP and lower adiponectin levels were observed in those who met any MetS criteria, whereas increased TNF-alpha was observed in only those with ATP-III-MetS. Finally, odds ratios (ORs) for MetS prevalence of a 1-SD increase/decrease in log-transformed 4 markers were calculated with multivariate logistic regression analyses. Consequently, decreased adiponectin was associated most strongly with ATP-III-MetS (adiponectin: OR, 1.90 [95% CI, 1.44 to 2.51]; P<0.001; CRP: OR, 1.33 [95% CI, 1.01 to 1.74]; P=0.03; TNF-alpha: OR, 1.25 [95% CI, 0.94 to 1.67]; P=0.12; and IL-6: OR, 0.87 [95% CI, 0.63 to 1.19]; P=0.37). This result was not altered by using the other 2 criteria. CONCLUSIONS: The present results raise the possibility that decreased serum adiponectin might be fundamentally involved in the development of MetS.
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Satoshi Shintani, Kengo Kusano, Masaaki Ii, Atsushi Iwakura, Lindsay Heyd, Cynthia Curry, Andrea Wecker, Mary Gavin, Hong Ma, Marianne Kearney, Marcy Silver, Tina Thorne, Toyoaki Murohara, Douglas W Losordo (2006)  Synergistic effect of combined intramyocardial CD34+ cells and VEGF2 gene therapy after MI.   Nat Clin Pract Cardiovasc Med 3 Suppl 1: S123-S128 Mar  
Abstract: Previous studies have shown that local angiogenic gene therapy acts, in part, by recruiting endothelial progenitor cells (EPCs) to ischemic tissue. Recent data indicate that patients with the most severe vascular disease may have insufficient or deficient EPCs and the poorest response to angiogenic therapy. Accordingly, we hypothesized that combining human CD34(+) cell implantation with local vascular endothelial growth factor 2 (phVEGF2) gene therapy might overcome these deficiencies. The addition of VEGF2 to EPC cultures resulted in significant and dose-dependent decreases in EPC apoptosis. Phosphorylated Akt (p-Akt) was increased in VEGF2-treated EPCs. In vivo, myocardial infarction (MI) was induced by ligation of the left anterior descending coronary artery in 34 immunodeficient rats. The animals were then randomized to one of four treatment groups: cell therapy alone with human CD34(+) cells; VEGF2 gene therapy alone; combination therapy with CD34(+) cells plus phVEGF2; or CD34(-) cells and 50 microg empty plasmid. Four weeks after MI, animals treated with combination therapy showed improved fractional shortening, increased capillary density, and reduced infarct size compared with the other three groups. Combination therapy was also associated with an increased number of circulating EPCs 1 week after MI. Combined subtherapeutic doses of cell and gene therapy result in a significant therapeutic effect compared to monotherapy. This approach may overcome therapeutic failures (e.g. inability of certain patients to mobilize sufficient EPCs) and may also offer safety advantages by allowing lower dosing strategies.
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Yasushi Numaguchi, Takahito Sone, Kenji Okumura, Masakazu Ishii, Yasuhiro Morita, Ryuji Kubota, Kazuhiko Yokouchi, Hajime Imai, Mitsunori Harada, Hiroyuki Osanai, Takahisa Kondo, Toyoaki Murohara (2006)  The impact of the capability of circulating progenitor cell to differentiate on myocardial salvage in patients with primary acute myocardial infarction.   Circulation 114: 1 Suppl. I114-I119 Jul  
Abstract: BACKGROUND: Circulating endothelial progenitor cells (EPCs) are known to be involved in vasculogenesis and mobilized after acute myocardial infarction (AMI). To test the hypothesis that the angiogenic function of EPCs affects post-myocardial infarction (MI) myocardial salvage, we evaluated the number and potential differentiation of EPCs and compared these data with clinical parameters 6 months after MI. METHODS AND RESULTS: Consecutive 51 patients (age, 61+/-8 years, mean+/-SD) with primary AMI who were successfully treated with stenting were enrolled. EPC identified as CD45low, CD34+, CD133+, and VEGFR2+ was quantified by a flow cytometry. The potential of EPCs to differentiate into endothelial cells (EPC differentiation) was also confirmed by the upregulation of CD31 and VEGFR2 after 7 days of culture. According to the proportion of EPC fraction, patients were divided into 2 groups (cut-off value=median). Although no difference was seen in myocardial damage shown by mean peak CK leakage and mean area at risk between the differentiated group (n=26) and nondifferentiated group (n=25), the number of attached cell was greater in differentiated group than in the nondifferentiated group (P=0.023). Left ventricular function and ischemic damaged area were assessed by scintigraphic images of (123)I-BMIPP in the acute phase and (99m)Tc-tetrofosmin in the chronic phase. We found that a greater increase in myocardial salvage (P=0.0091), decrease in end-systolic volume (P=0.012), and recovery of ejection fraction (P=0.011) occurred in the group with differentiated EPCs than in the nondifferentiated group. CONCLUSIONS: In patients with primary AMI, the capability of EPCs to differentiate influences the functional improvement and infarct size reduction, indicating that manipulation of EPCs could be a novel therapeutic target to salvage ischemic damage.
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Masayuki Shimano, Yasuya Inden, Yukihiko Yoshida, Yukiomi Tsuji, Naoya Tsuboi, Taro Okada, Takumi Yamada, Yoshimasa Murakami, Yasunobu Takada, Haruo Hirayama, Toyoaki Murohara (2006)  Does RV lead positioning provide additional benefit to cardiac resynchronization therapy in patients with advanced heart failure?   Pacing Clin Electrophysiol 29: 10. 1069-1074 Oct  
Abstract: BACKGROUND AND OBJECTIVES: The left ventricular (LV) stimulation site is currently recommended to position the lead at the lateral wall. However, little is known as to whether right ventricular (RV) lead positioning is also important for cardiac resynchronization therapy. This study compared the acute hemodynamic response to biventricular pacing (BiV) at two different RV stimulation sites: RV high septum (RVHS) and RV apex (RVA). METHODS AND RESULTS: Using micro-manometer-tipped catheter, LV pressure was measured during BiV pacing at RV (RVA or RVHS) and LV free wall in 33 patients. Changes in LV dP/dt(max) and dP/dt(min) from baseline were compared between RVA and RVHS. BiV pacing increased dP/dt(max) by 30.3 +/- 1.2% in RVHS and by 33.3 +/- 1.7% in RVA (P = n.s.), and decreased dP/dt(min) by 11.4 +/- 0.7% in RVHS and by 13.0 +/- 1.0% in RVA (P = n.s.). To explore the optimal combination of RV and LV stimulation sites, we assessed separately the role of RV positioning with LV pacing at anterolateral (AL), lateral (LAT), or posterolateral (PL) segment. When the LV was paced at AL or LAT, the increase in dP/dt(max) with RVHS pacing was smaller than that with RVA pacing (AL: 12.2 +/- 2.2% vs 19.3 +/- 2.1%, P < 0.05; LAT: 22.0 +/- 2.7% vs 28.5 +/- 2.2%, P < 0.05). There was no difference in dP/dt(min) between RVHS- and RVA pacing in individual LV segments. CONCLUSIONS: RVHS stimulation has no overall advantage as an alternative stimulation site for RVA during BiV pacing. RVHS was equivalent with RVA in combination with the PL LV site, while RVA was superior to RVHS in combination with AL or LAT LV site.
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Xian Wu Cheng, Koji Obata, Masafumi Kuzuya, Hideo Izawa, Kae Nakamura, Eri Asai, Tetsuro Nagasaka, Masako Saka, Takahiro Kimata, Akiko Noda, Kohzo Nagata, Hai Jin, Guo-Ping Shi, Akihisa Iguchi, Toyoaki Murohara, Mitsuhiro Yokota (2006)  Elastolytic cathepsin induction/activation system exists in myocardium and is upregulated in hypertensive heart failure.   Hypertension 48: 5. 979-987 Nov  
Abstract: Cathepsins are cysteine proteases that participate in various types of tissue remodeling. However, their expressions during myocardial remodeling have not been examined. In this study, we investigated their expressions in the left ventricular (LV) myocardium of rats and humans with hypertension-induced LV hypertrophy or heart failure (HF). Real-time PCR and immunoblot analysis revealed that the abundance of cathepsin S mRNA or protein in the LV tissues was greater in rats or humans with HF than in those with hypertrophy or in control subjects. Immunostaining showed that cathepsin S was localized predominantly to cardiac myocytes and coronary vascular smooth muscle cells, but also overlapped in part with macrophages. Elastic lamina fragmentations significantly increased in the LV intramyocardial coronary arteries of HF rats. The amount of elastolytic activity in the extract of the LV myocardium was markedly increased for HF rats compared with controls, and this activity was mostly because of cathepsin S. Although the amount of elastin mRNA was increased in the LV myocardium of HF rats, the area of interstitial elastin was not. The expression of interleukin 1beta was increased in the LV myocardium of HF rats, and this cytokine was found to increase the expression and activity of cathepsin S in cultured neonatal cardiomyocytes. These results suggest that cathepsin S participates in pathological LV remodeling associated with hypertension-induced HF. This protease is, thus, a potential target for therapeutics aimed at preventing or reversing cardiac remodeling.
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Hideo Izawa, Takahisa Kondo, Akihiko Usui, Koji Yamamoto, Satoshi Shintani, Yasuya Inden, Satoshi Isobe, Kazumasa Unno, Masahiro Kajiguchi, Tomoko Kato, Akiko Noda, Kenji Okumura, Tomoki Naoe, Junki Takamatsu, Kimihiro Komori, Yuichi Ueda, Toyoaki Murohara (2006)  Clinical protocol for angiogenesis by intramyocardial injection of autologous bone marrow mononuclear cells in patients with severe coronary artery disease: TACT-NAGOYA-HEART.   Circ J 70: 9. 1180-1183 Sep  
Abstract: BACKGROUND: Despite recent improvements in the treatments of coronary artery disease (CAD), there are a considerable number of patients who can not receive complete revascularization because of severe or total arterial occlusion. Intramyocardial injection of autologous bone marrow mononuclear cells (ABMMCs) has been shown to induce neovascularization of ischemic myocardium. METHODS AND RESULTS: The study will investigate the safety and feasibility of intramyocardial injections of ABMMCs and test the hypothesis that this treatment would promote neovascularization and improve left ventricular (LV) global and/or regional function in patients with severe CAD who have no other option. ABMMCs (approximately 10(6) cells) will be injected into the area of ischemic myocardium where the coronary artery is not graftable, in combination with bypass surgery to the other coronary branches. Myocardial perfusion and LV global and regional function will be evaluated, based on the micromanometer-tipped catheter method, single-photon emission tomography, and myocardial enhanced and color tissue Doppler echocardiography at baseline and during 12 month follow-up. CONCLUSIONS: This project will demonstrate that intramyocardial injection of ABMMCs with or without coronary artery bypass surgery could be a safe and effective method for therapeutic neovascularization, resulting in an improvement of cardiac function in patients with severe CAD.
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Satoshi Isobe, Yasuo Takada, Akitada Ando, Satoru Ohshima, Kiyoyasu Yamada, Mamoru Nanasato, Kazumasa Unno, Takuo Ogawa, Takahisa Kondo, Hideo Izawa, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2006)  Increase in electrocardiographic R-waves after revascularization in patients with acute myocardial infarction.   Circ J 70: 11. 1385-1391 Nov  
Abstract: BACKGROUND: The physiological mechanism of the increase in the electrocardiographic (ECG) R-wave voltage after revascularization in patients with acute myocardial infarction (MI) needs to be elucidated. METHODS AND RESULTS: One hundred and thirty-eight MI patients (83: anterior MI, 45: inferior MI, 10: lateral MI) underwent ECG and echocardiography in both the acute and subacute phases after emergency revascularization, as well as a resting thallium-201/iodine-123 15-p-iodophenyl-3-(R,S)-methyl pentadecanoic acid myocardial scintigraphy in the acute phase. The total sum of the R-wave voltage (SigmaR) was calculated over multiple leads on ECG for each infarcted lesion. Scintigraphic defect on each tracer was expressed as the percentage (%) defect of the total left ventricular (LV) myocardium. The % defect-discordance on both images in the acute phase and the % increase in SigmaR and the absolute increase in LV ejection fraction from the acute to the subacute phase (DeltaEF) were also calculated. The SigmaR in the subacute phase was significantly greater than that in the acute phase (p<0.0001). The % increase in SigmaR significantly correlated with the DeltaEF (r=0.57, p<0.0001). The % increase in SigmaR also correlated with the % defect-discordance (r=0.68, p<0.0001). CONCLUSIONS: The increase in the ECG R-wave voltage reflects not only the improvement in myocardial perfusion but also the presence of salvaged myocardium after revascularization in acute MI patients.
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Tomoko Gochi, Hisashi Umeda, Naoki Yoshida, Hironobu Maekawa, Kosuke Watanabe, Taro Okada, Toshiaki Katoh, Toru Asai, Tomomitsu Tani, Masaki Yokoya, Yoshimasa Murakami, Toyoaki Matsushita, Takeshi Shimizu, Yukio Ozaki, Shinya Hiramitsu, Toyoaki Murohara, Masanori Nomura, Shinichiro Morimoto, Hitoshi Hishida (2006)  Promising efficacy of the sirolimus-eluting stent in patients with acute myocardial infarction   J Cardiol 48: 5. 253-261 Nov  
Abstract: OBJECTIVES: This study investigated the safety and efficacy of sirolimus-eluting stents (SESs) on early and late outcomes in patients with acute myocardial infarction. METHODS: A series of 100 consecutive patients (September 2004 to November 2005)with acute myocardial infarction undergoing primary stenting using SES ptember 24 hr) was compared with 100 consecutive patients (September 2003 to August 2004) treated with bare metal stent (BMS). The frequency of major adverse cardiac events (MACE) and stent thrombosis, and status of ticlopidine administration were assessed at 270 days. RESULTS: The rates of premature discontinuation of ticlopidine (SES group <3 months: 11%, BMS group <1 month: 11%, p = NS) and stent thrombosis (SES group: 1%, BMS group: 0%, p = NS) were similar in the two groups. At follow-up, restenosis rate and target vessel revascularization rate were lower in the SES group(4% vs 19%, p < 0.001 and 4% vs 10%, p = 0.149, respectively). Furthermore, the occurrence of MACE at 270 days was significantly less frequent in the SES group compared with the BMS group (6% vs. 17%, p = 0.038). Multivariate analysis showed SES use tended to predict 270-day MACE (hazard ratio 0.37, 95% confidence interval 0.14-1.02, p = 0.055). Culprit lesion located in the left main trunk was identified as an independent predictor of 270-day MACE (hazard ratio 5.43, 95% confidence interval 1.07-27.59, p = 0.041). CONCLUSIONS: The use of a SES was not associated with increased risk of stent thrombosis compared with a BMS. With lower rates of restenosis and subsequent target vessel revascularization, SES placement could provide superior outcomes in patients with acute myocardial infarction.
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Yinghua Li, Hirokazu Nagai, Toshihito Ohno, Haruhiko Ohashi, Toyoaki Murohara, Hidehiko Saito, Tomohiro Kinoshita (2006)  Aberrant DNA demethylation in promoter region and aberrant expression of mRNA of PAX4 gene in hematologic malignancies.   Leuk Res 30: 12. 1547-1553 Dec  
Abstract: The PAX4 gene, a member of the paired box (PAX) gene family, is thought to be involved in regulating the fate of beta-cells in the mammalian pancreas. We observed the aberrant expression of PAX4 mRNA in 10 of 15 hematologic cell lines analyzed by RT-PCR. The restoration of PAX4 gene expression after treatment with the demethylating agent 5-aza-2'-deoxycitidine, as well as bisulfite sequencing analysis, indicated that gene overexpression was caused by DNA demethylation at the promoter region. Such DNA demethylation also was observed in primary lymphoma (20 out of 45 patients) on combined bisulfite restriction assay (COBRA). Forced expression of the PAX4 gene in the HEK293 and SHSY/610 cell lines conferred positive effects on cell growth. This profile of PAX4 thus corresponds to that of a candidate oncogene in hematologic malignancies.
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Kiyoyasu Yamada, Satoshi Isobe, Makoto Hirai, Kazumasa Unno, Satoru Ohshima, Yasuo Takada, Hideo Izawa, Kazunari Abe, Mitsuhiro Yokota, Toyoaki Murohara (2006)  Changes with age in left ventricular function and volumes at rest and postexercise in postmenopausal women.   Ann Nucl Med 20: 10. 677-681 Dec  
Abstract: OBJECTIVES: In postmenopausal women, it has been reported that the plasma estrogen levels diminish immediately after menopause, and that this phenomenon affects left ventricular (LV) function and volumes. However, the effects of age on LV function and volumes for a relatively short period in the postmenopausal women remain to be established. Electrocardiographically gated-myocardial single-photon emission computed tomography (SPECT) has recently provided accurate estimations of perfusion, cardiac systolic and diastolic functions. We investigated the age-related changes in LV function and volumes in postmenopausal women using electrocardiographically gated-myocardial scintigraphy. METHODS: Twenty-two consecutive healthy postmenopausal women (mean age of 63.8 +/- 9.4 years, from 42 to 77 years) without cardiac disease underwent stress/rest technetium-99m tetrofosmin gated-myocardial SPECT with 16 frames per cardiac cycle at baseline and follow-up (1.0 +/- 0.3 years later). LV ejection fraction (LVEF) and LV volumes were calculated by QGS software. Fourier series were retained for the analysis of the volume curve. From this volume curve, we derived the following diastolic indices: peak filling rate (PFR) and time to PFR (TPFR). RESULTS: End-systolic volume index (ESVI) significantly decreased at postexercise (p = 0.02) and tended to decrease at rest (p = 0.06) from the baseline to the follow-up study. LVEF significantly increased at both postexercise (p = 0.01) and rest (p = 0.03) from the baseline to the follow-up study. The TPFR at rest tended to be prolonged from the baseline to the follow-up study (p = 0.07). The absolute increase in LVEF at postexercise tended to decrease with age [4.8% (50s) vs. 3.4% (60s) vs. 1.2% (70s)]. CONCLUSIONS: An age-related change in cardiac performance is apparent at an approximately 1 year follow-up in postmenopausal women. In particular, the increase in LV systolic function tends to show the greatest value in the 50s subjects among the 3 generations.
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Hideki Ishii, Satoshi Ichimiya, Masaaki Kanashiro, Toru Aoyama, Yasuhiro Ogawa, Ryuichiro Murakami, Tetsuya Amano, Keiko Naruse, Tatsuaki Matsubara, Toyoaki Murohara (2006)  Effects of receipt of chronic statin therapy before the onset of acute myocardial infarction: a retrospective study in patients undergoing primary percutaneous coronary intervention.   Clin Ther 28: 11. 1812-1819 Nov  
Abstract: BACKGROUND: Studies have reported an association between receipt of statin therapy and a reduction in complications after elective percutaneous coronary intervention (PCI). However, there are limited data on the effects of chronic statin therapy before the occurrence of an acute myocardial infarction (AMI). OBJECTIVE: This study investigated whether administration of chronic statin therapy before AMI was associated with a reduction in reperfusion injury in AMI patients undergoing PCI. METHODS: This was a retrospective study of consecutive patients with a first AMI who underwent successful reperfusion therapy with PCI within 24 hours after the onset of AMI between April 1998 and October 2003. Patients were stratified according to whether they had or had not been receiving chronic statin therapy for > or = 1 month before the onset of AMI. The following end points were compared after PCI: electrocardiographic resolution of ST segment elevation, defined as a reduction of > or = 50% from the initial value; achievement of Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow; corrected TIMI frame count (cTFC); maximum serum creatine kinase (CK) level; and the type and frequency of ventricular arrhythmias. RESULTS: The study enrolled 386 patients, 40 of whom had been receiving statin therapy before the onset of AMI. The clinical characteristics of the 2 groups were similar at baseline, with the exceptions of a significantly higher rate of hyperlipidemia in the statin group compared with the nonstatin group (P < 0.001), significantly greater chronic use of aspirin therapy (P < 0.001), and significantly greater chronic use of antihypertensive medications (beta-blockers: P = 0.004; angiotensin-converting enzyme inhibitors/angiotensin II-receptor blockers: P = 0.007; calcium channel blockers: P = 0.006). Electrocardiographic ST segment resolution after PCI was observed in 87.5% and 69.9% of the statin and nonstatin groups, respectively (hazard ratio [HR]: 3.01; 95% CI, 1.15-7.90; P = 0.025). Achievement of TIMI grade 3 flow after PCI was seen in 95.0% of the statin group and 83.5% of the nonstatin group (HR: 3.75; 95% CI, 0.88-16.0; P = NS). Patients treated with a statin had a significantly lower mean (SD) maximum CK level compared with the nonstatin group (2300 [1449] vs 3538 [3170] IU/mL, respectively; P = 0.015) and a lower cTFC after PCI (18.8 [4.0] vs 24.2 [14.2]; P = 0.017). The difference in reperfusion arrhythmias between groups was not statistically significant. After adjustment for baseline covariates, pretreatment with a statin was found to be an independent predictor of ST segment resolution after PCI (HR: 2.95; 95% CI, 1.08-8.09; P = 0.035) and prevention of impaired coronary flow (HR: 3.00; 95% CI, 1.63-5.55; P < 0.001). CONCLUSION: In this study, receipt of chronic statin therapy before the onset of AMI was associated with improvement in epicardial perfusion and a reduction in myocardial necrosis after PCI.
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Kazuhiko Yokouchi, Yasushi Numaguchi, Ryuji Kubota, Masakazu Ishii, Hajime Imai, Ryuichiro Murakami, Yasuhiro Ogawa, Takahisa Kondo, Kenji Okumura, Donald E Ingber, Toyoaki Murohara (2006)  l-Caldesmon regulates proliferation and migration of vascular smooth muscle cells and inhibits neointimal formation after angioplasty.   Arterioscler Thromb Vasc Biol 26: 10. 2231-2237 Oct  
Abstract: OBJECTIVE: Light-type caldesmon (l-CaD) is a potent cytostatic and antiangiogenic protein that regulates cell growth and survival via modulation of the cell shape and cytoskeleton. The aim of this study is to explore the potential value of l-CaD for use as a cytostatic agent to inhibit neointimal formation after angioplasty by suppressing vascular smooth muscle cell (VSMC) growth and migration. METHODS AND RESULTS: We tested the cytostatic function of l-CaD in cultured VSMCs using assays for apoptosis, cell proliferation, and migration, and evaluated the expression pattern of relevant signaling proteins (focal adhesion kinase [FAK] and mitogen-activated protein kinases) in VSMCs. Transfection of adenoviral vector encoding l-CaD (Ad-l-CaD) resulted in progressive loss of actin stress fibers and cell retraction. Enzyme-linked immunosorbent assay demonstrated that Ad-l-CaD transfection increased the apoptosis rate by 75% and reduced BrdU uptake by 49%. Furthermore, transfection of Ad-l-CaD inhibited migration of VSMCs induced by platelet-derived growth factor-BB (PDGF) by 36% (P<0.05). Immunoblotting analysis revealed that l-CaD overexpression reduced PDGF-induced phosphorylation of both FAK and extracellular signal regulated-kinase (ERK). In balloon-injured rat carotid arteries, Ad-l-CaD transfection inhibited neointimal formation by 37% (P<0.05) without delaying re-endothelialization at 14 days. CONCLUSIONS: Overexpression of l-CaD suppressed cell growth and survival in VSMCs and inhibited neointimal formation after experimental angioplasty, partly by regulating the cytoskeletal tension-FAK-ERK axis.
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Satoshi Isobe, Sotirios Tsimikas, Jun Zhou, Shinichiro Fujimoto, Masayoshi Sarai, Michael J Branks, Ai Fujimoto, Leonard Hofstra, Chris P Reutelingsperger, Toyoaki Murohara, Renu Virmani, Frank D Kolodgie, Navneet Narula, Artiom Petrov, Jagat Narula (2006)  Noninvasive imaging of atherosclerotic lesions in apolipoprotein E-deficient and low-density-lipoprotein receptor-deficient mice with annexin A5.   J Nucl Med 47: 9. 1497-1505 Sep  
Abstract: Transgenic mice such as apolipoprotein E-deficient (apoE(-/-)) and low-density-lipoprotein receptor-deficient (LDLR(-/-)) mice exhibit hypercholesterolemia and develop complex atherosclerotic lesions similar to those seen in humans. Radiolabeled annexin A5 has been successfully used to noninvasively image experimental and clinical atherosclerotic disease. We evaluated the feasibility of annexin A5 imaging in transgenic apoE(-/-) and LDLR(-/-) mice with or without a cholesterol diet. METHODS: Thirty-three mice (mean age, 62 +/- 0.9 wk old) were used. Of these 33 mice, apoE(-/-) mice with the cholesterol diet for 4 mo (n = 5) and without the cholesterol diet (n = 8) and LDLR(-/-) mice with the cholesterol diet for 6 mo (n = 7) and without the cholesterol diet (n = 7) were compared with 6 normal wild-type (C57BL/6) mice with the same genetic background. (99m)Tc-annexin A5 was injected in 31 animals for noninvasive imaging using micro-SPECT/CT. After in vivo micro-SPECT/CT, aortas were explanted to acquire ex vivo images and calculate the percentage injected dose per gram (%ID/g) annexin uptake, followed by histologic and immunohistochemical characterization. For the evaluation of precise target localization, biotinylated annexin A5 was injected in the remaining 2 normally fed apoE(-/-) mice. RESULTS: Aortic lesions were clearly visualized noninvasively by micro-SPECT and aorta calcification was detectable by micro-CT. The quantitative uptake of annexin A5 was highest in the cholesterol-fed apoE(-/-) (0.88 +/- 0.27 %ID/g) mice, followed by the normal chow-fed apoE(-/-) (0.60 +/- 0.16 %ID/g), the cholesterol-fed LDLR(-/-) (0.59 +/- 0.14 %ID/g), the chow-fed LDLR(-/-) (0.40 +/- 0.31 %ID/g), and the control (0.15 +/- 0.05 %ID/g) mice. The histologic extent of atherosclerosis paralleled radiotracer uptake, and immunohistochemical studies revealed a significant correlation between radiotracer uptake and both macrophage infiltration and the extent of apoptosis. Intravenously injected biotinylated annexin A5 localized in apoptotic and nonapoptotic macrophages. CONCLUSION: This study demonstrates the feasibility of noninvasive imaging of atherosclerosis with radiolabeled annexin A5 in transgenic mouse models of human atherosclerosis.
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Masako Saka, Koji Obata, Sahoko Ichihara, Xian Wu Cheng, Hirotaka Kimata, Takao Nishizawa, Akiko Noda, Hideo Izawa, Kohzo Nagata, Toyoaki Murohara, Mitsuhiro Yokota (2006)  Pitavastatin improves cardiac function and survival in association with suppression of the myocardial endothelin system in a rat model of hypertensive heart failure.   J Cardiovasc Pharmacol 47: 6. 770-779 Jun  
Abstract: Statin therapy may be associated with lower mortality in patients with heart failure, but the underlying mechanism of such an association is unknown. We have evaluated the effects of pitavastatin on cardiac function and survival in a rat model of hypertensive heart failure and investigated the molecular mechanism of the observed effects. Dahl salt-sensitive rats fed with high-salt diet from 7 weeks of age developed compensatory left ventricular hypertrophy at 12 weeks and heart failure at 19 weeks. Dahl salt-sensitive rats were treated with either vehicle or pitavastatin (0.3 mg/kg per day) from 7 or 12 weeks. Both early-onset and late-onset pitavastatin treatment reduced left ventricular fibrosis, improved cardiac function, and increased the survival rate apparent at 19 weeks. The increases in the expression levels of hypertrophic, profibrotic, and metalloproteinase genes as well as in gelatinase activities in the heart induced by the high-salt diet were suppressed by pitavastatin treatment. Furthermore, the level of cardiac endothelin-1 was increased in association with the development of heart failure in a manner sensitive to treatment with pitavastatin. Both early and late pitavastatin treatment thus improved cardiac function and survival, with modulation of extracellular matrix remodeling and endothelin-1 signaling possibly contributing to these beneficial effects.
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Yosuke Murase, Yuji Narita, Hideaki Kagami, Keiichi Miyamoto, Yuichi Ueda, Minoru Ueda, Toyoaki Murohara (2006)  Evaluation of compliance and stiffness of decellularized tissues as scaffolds for tissue-engineered small caliber vascular grafts using intravascular ultrasound.   ASAIO J 52: 4. 450-455 Jul/Aug  
Abstract: This study evaluated the compliance and stiffness of decellularized canine common carotid artery as well as decellularized canine ureter and compared it with that of polytetrafluoroethylene, elastin gel combined with polylactic acid tube, and canine common carotid artery. To calculate the compliance and stiffness, internal diameters and cross-sectional areas were measured according to changes in the intraluminal pressures using intravascular ultrasound in a closed circuit system equipped with a syringe pump. The pressure-area curve, stiffness parameter beta, and diameter compliance were evaluated. Canine common carotid artery and decellularized canine common carotid artery, as well as decellularized canine ureter, showed a compliant response, a J-shaped curve. However, the latter evidenced different characteristics in the low pressure range. Although the cross-sectional area of the elastin gel combined with polylactic acid tube showed some changes, it did not present a J-shape curve. Polytetrafluoroethylene exhibited a noncompliant response.The results in this study have shown that the compliance in the decellularized matrices was maintained after cell extraction, which demonstrated the importance of the remaining matrix structure in the mechanical properties of decellularized tissue. A clear difference between the decellularized matrices and synthetic materials was noted in terms of the compliance, even in materials composed of relatively elastic materials.
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Takumi Yamada, Yoshimasa Murakami, Taro Okada, Mitsuhiro Okamoto, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Teruo Ito, Masahiro Muto, Takahisa Kondo, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2006)  Plasma atrial natriuretic Peptide and brain natriuretic Peptide levels after radiofrequency catheter ablation of atrial fibrillation.   Am J Cardiol 97: 12. 1741-1744 Jun  
Abstract: It has been reported that plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels are elevated in patients with atrial fibrillation (AF). The aim of this study was to investigate the change in these patients after pulmonary vein isolation (PVI). In 66 patients with paroxysmal AF (PAF) and without any structural heart disease, plasma ANP and BNP levels were measured before and 3 months after successful PVI. At baseline, in 14 patients, ANP and BNP levels were elevated, and in 52 patients, only BNP levels were elevated. There were no significant relations between the attack frequency or the duration of PAF episodes and ANP or BNP levels. Neither ANP nor BNP level at baseline was a valid predictor of AF recurrence. Even in 31 patients (47%) with recurrent PAF, attacks of PAF were significantly reduced. In 66 patients with elevated ANP and/or BNP levels at baseline, levels were significantly reduced after PVI independent of PAF recurrence (ANP: 69.0+/-23.0 vs 25.0+/-7.7 pg/ml, p<0.0001; BNP: 58.4+/-50.7 vs 22.5+/-27.1 pg/ml, p<0.0001). In 42 patients without AF recurrences, ANP and BNP levels were reduced to within the normal range. In conclusion, in patients with PAF without any structural heart disease, ANP and/or BNP levels were elevated. In those patients, relief of the AF burden by successful PVI significantly reduced elevated plasma ANP and BNP levels.
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Kaoru Yasuda, Hirotake Kasuga, Toru Aoyama, Hiroshi Takahashi, Takanobu Toriyama, Yasumasa Kawade, Shigejiro Iwashima, Shigeki Yamada, Hirohisa Kawahara, Shoichi Maruyama, Yukio Yuzawa, Hideki Ishii, Toyoaki Murohara, Seiichi Matsuo (2006)  Comparison of percutaneous coronary intervention with medication in the treatment of coronary artery disease in hemodialysis patients.   J Am Soc Nephrol 17: 8. 2322-2332 Aug  
Abstract: It has been reported that percutaneous coronary intervention (PCI) is beneficial for coronary artery disease (CAD) among the general population. However, its effects in patients who are on hemodialysis (HD) remain unclear. A prospective cohort study was performed to clarify whether PCI has a therapeutic advantage over medical therapy among HD patients with CAD. A follow-up study to 5 yr was conducted among 259 HD patients with ischemic heart disease. Mean follow-up was 39 mo. Patients were divided into three groups: 122 patients without significant stenosis, 88 patients who had significant stenosis and were treated with PCI, and 49 patients who had significant stenosis and were treated with medication only. The primary end point was cardiac death, and the secondary end point was all-cause death. The results showed that the 5-yr cardiac survival rate was 41.6% in the medication group, 77.1% in the PCI group (P = 0.0006), and 84.5% in the nonstenosis group (P < 0.0001). The 5-yr all-cause survival rate was 19.3% in the medication group, 48.4% in the PCI group (P = 0.004), and 64.3% in the nonstenosis group (P < 0.0001). Even after adjustment for other risk factors, effects of PCI on the risk for cardiac and all-cause death remained significant and independent (odds ratio 0.14; 95% confidence interval 0.08 to 0.25, P = 0.0006; and odds ratio 0.37; 95% confidence interval 0.26 to 0.54, P = 0.0062, respectively). Results were consistent when the therapeutic effect of PCI or medication was analyzed using propensity-matched patients. These data suggested that PCI could improve the prognosis of HD patients with CAD. PCI would be recommended for HD patients with CAD.
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Sahoko Ichihara, Koji Obata, Yoshiji Yamada, Kohzo Nagata, Akiko Noda, Gaku Ichihara, Akira Yamada, Tomoko Kato, Hideo Izawa, Toyoaki Murohara, Mitsuhiro Yokota (2006)  Attenuation of cardiac dysfunction by a PPAR-alpha agonist is associated with down-regulation of redox-regulated transcription factors.   J Mol Cell Cardiol 41: 2. 318-329 Aug  
Abstract: Peroxisome proliferator-activated receptor-alpha (PPAR-alpha) is a key regulator of lipid and glucose metabolism and is implicated in inflammation. We investigated the effects of the PPAR-alpha activator fenofibrate on, as well as the role of redox-regulated transcription factors, in the development of left ventricular (LV) hypertrophy and heart failure in Dahl salt-sensitive (DS) rats. DS rats were fed a high-salt diet and treated with either fenofibrate (30 or 50 mg/kg per day) or vehicle from 7 weeks of age. Fenofibrate inhibited the development of compensated hypertensive LV hypertrophy, attenuated the LV relaxation abnormality and systolic dysfunction, and improved the survival rate in DS rats. It also prevented a decrease in the ratio of reduced to oxidized glutathione and inhibited up-regulation of the DNA binding activities of the redox-regulated transcription factors NF-kappaB, AP-1, Egr-1, SP1, and Ets-1 induced in the left ventricle by the high-salt diet. Expression of target genes for these transcription factors, including those for adhesion molecules (VCAM-1, ICAM-1), cytokines (MCP-1), growth factors (TGF-beta, PDGF-B), and osteopontin, was also increased by the high-salt diet in a manner sensitive to treatment with fenofibrate. Furthermore, the infiltration of macrophages and T lymphocytes into the left ventricle and the increase in the plasma concentration of C-reactive protein were inhibited by fenofibrate. The PPAR-alpha activator fenofibrate thus attenuated the progression of heart failure and improved the survival rate in this rat model. These effects were associated with inhibition of the inflammatory response and of activation of redox-regulated transcription factors in the left ventricle.
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Toshihisa Hirai, Kenji Okumura, Yasuhiro Nishimoto, Takanori Shumiya, Ryuichiro Murakami, Ryotaro Takahashi, Toru Asai, Hisashi Murakami, Yasushi Numaguchi, Hideo Matsui, Toyoaki Murohara (2006)  Upregulation of renal eNOS by high-sodium diet facilitates hypertension in doxorubicin-treated rats through enhanced oxidative stress.   Toxicology 225: 2-3. 81-89 Aug  
Abstract: It is known that renal nitric oxide (NO) is an important controller of urinary sodium excretion. A defect in the kidney's NO system could cause salt-sensitive hypertension. Since it has been demonstrated that doxorubicin binds to the reductase domain of endothelial NO synthase (eNOS) and generates superoxide in vitro, we tested our hypothesis that a high-sodium diet would upregulate the expression of eNOS and enhance oxidative stress in the kidney of doxorubicin-treated rats, resulting in a facilitation of hypertension. At 4 weeks after treatment with doxorubicin in Sprague-Dawley rats, the systolic blood pressure significantly increased only in the high-sodium diet group. The expressions of eNOS protein in the renal cortex and medulla were significantly higher in high-sodium groups than in normal-sodium groups, regardless of doxorubicin treatment. In rats treated with doxorubicin, a biomarker of oxidative damage 8-hydroxy-2'-deoxyguanosine (8-OHdG) immunohistological staining of renal tissues showed strong staining of the proximal and distal tubules. In particular, rats with doxorubicin in the high-sodium diet group demonstrated a significant increase in urinary exertion of 8-OHdG as well as more prominently stained tubules against 8-OHdG antibody, but markedly lower urinary NO(x) excretion than in rats without doxorubicin, even than in the untreated, low-sodium group. In conclusion, these results indicate that the oxidative stress induced by doxorubicin impairs NO production in the kidney. As such, doxorubicin treatment appears to contribute to the development of salt-sensitive hypertension through reductive activation of upregulated eNOS by a high-sodium diet instead of NO production.
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Hiroyuki Otsuka, Hidetoshi Akashi, Toyoaki Murohara, Teiji Okazaki, Satoshi Shintani, Keiichiro Tayama, Ken-ichiro Sasaki, Tsutomu Imaizumi, Shigeaki Aoyagi (2006)  The prostacyclin analog beraprost sodium augments the efficacy of therapeutic angiogenesis induced by autologous bone marrow cells.   Ann Vasc Surg 20: 5. 646-652 Sep  
Abstract: Implantation of autologous bone marrow (BM) mononuclear cells (MNCs) has been shown to augment neovascular formation in ischemic tissues in experimental animals and in humans. Prostaglandin derivatives improve the symptoms of patients with critical limb ischemia, possibly by their vasodilating and antiplatelet actions. We therefore examined whether therapeutic angiogenesis by implantation of autologous BM-MNCs would be enhanced by beraprost sodium (BPS), using a rabbit ischemic hindlimb model. Ischemia was induced by surgical resection of the left femoral artery. Twenty-five New Zealand white rabbits were divided into four groups. The first group (BM group, n = 4) received autologous BM-MNCs (2 x 10(6)/animal) implanted into the ischemic tissue 1 week after limb ischemia. The second group (BM+BPS group, n = 8) received BPS injected into the dorsal skin (300 microg/kg daily) starting 1 week before limb surgery. This group received BM-MNC implantation 1 week after surgery. Daily injection of BPS was continued until the end of the protocol. The third group (BPS group, n = 8) received BPS injected into the dorsal skin (600 microg/kg daily) starting 1 week before limb surgery. The fourth group received saline as a control (n = 4). The extent of angiogenesis in the ischemic hindlimb was assessed using the angiographic score (AS), ischemic/normal limb calf blood pressure ratio (CBPR), and tissue capillary density. Four weeks after limb ischemia, the ischemic/normal CBPR was highest in the BM+BPS group, followed by the BPS, BM, and control groups (0.56 +/- 0.16, 0.51 +/- 0.25, 0.44 +/- 0.15, and 0.30 +/- 0.10, respectively). The AS was also the greatest in the BM+BP group, followed by the BM, BP, and S group (1.63 +/-0.21, 1.31 +/- 0.25, 1.26 +/- 0.21 and 0.80 +/- 0.10, respectively). The TCD was greatest in the BM+BP group, followed in by the BM, BP, and S group? (46 +/- 4.1, 34 +/- 0.7, 33 +/- 6.9, and 19 +/- 1.8 per field, respectively). BP treatment is an effective means to enhance the efficacy of therapeutic angiogenesis induced by autologous BM-MNCs implantation in ischemic hindlimb tissues.
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Weon Kim, Myung Ho Jeong, Suk Hee Cho, Ji Hye Yun, Hong Jae Chae, Young Keun Ahn, Min Cheol Lee, Xianwu Cheng, Takahisa Kondo, Toyoaki Murohara, Jung Chaee Kang (2006)  Effect of green tea consumption on endothelial function and circulating endothelial progenitor cells in chronic smokers.   Circ J 70: 8. 1052-1057 Aug  
Abstract: BACKGROUND: The present study was designed to investigate the effect and relationship of endothelial function and endothelial progenitor cells (EPCs) by green tea consumption in chronic smokers. The numbers of circulating EPCs have an inverse correlation with chronic smoking and endothelial dysfunction. Green tea catechin improved endothelial dysfunction in chronic smokers. METHOD AND RESULTS: In 20 young healthy smokers, endothelial functions, defined by flow-mediated endothelium dependent vasodilation (FMD) of the brachial artery via ultrasound as well as the number of EPCs isolated from peripheral blood, were determined at baseline and at 2 weeks after green tea consumption (8 g/day). Circulating EPCs were quantified by flow cytometry as CD45lowCD34+KDR2+ cells and by acyl-low-density lipoprotein and fluorescein isotiocyanate-lectin double positive cells after culture for 7 days. Clinical characteristics and laboratory findings were not significantly different between the baseline and at 2 weeks after green tea intake. EPC levels were inversely correlated with the number of cigarettes smoked. Circulating EPCs by flow cytometry (78.6+/-72.6 vs 156.1+/-135.8 /ml, p<0.001) and cultured EPCs (118.2+/-35.7 vs 169.31+/-58.3/10 field, p<0.001) increased rapidly at 2 weeks after green tea consumption. FMD was significantly improved after 2 weeks (7.2+/-2.8 vs 9.3+/-2.4, p<0.001). The FMD correlated with EPC counts (r=0.67, p=0.003) before treatment and after 2 weeks (r=0.60, p=0.013). CONCLUSIONS: A short-term administration of green tea consumption induces a rapid improvement of EPC levels and FMD. Green tea consumption may be effective to prevent future cardiovascular events in chronic smokers.
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Ryotaro Takahashi, Kenji Okumura, Toru Asai, Toshihisa Hirai, Hisashi Murakami, Ryuichiro Murakami, Yasushi Numaguchi, Hideo Matsui, Masafumi Ito, Toyoaki Murohara (2005)  Dietary fish oil attenuates cardiac hypertrophy in lipotoxic cardiomyopathy due to systemic carnitine deficiency.   Cardiovasc Res 68: 2. 213-223 Nov  
Abstract: OBJECTIVE: 1,2-Diacylglycerol (DAG), a lipid second messenger that activates protein kinase C (PKC), is increased with a distinct fatty acid composition in the heart of the juvenile visceral steatosis (JVS) mouse, which develops pathological cardiac hypertrophy with lipid accumulation induced by the perturbation of fatty acid beta-oxidation due to systemic carnitine deficiency. Fish oil (FO) may exert its beneficial effects on the cardiomyopathy in JVS mice by modifying the molecular species composition of myocardial DAG. To test this hypothesis, we investigated the effects of dietary FO on the hypertrophied hearts in JVS mice. METHODS: Both control and JVS mice were fed a FO diet (containing 10% FO) or a standard diet from 4 weeks of age. RESULTS: At 8 weeks of age, the ventricular-to-body weight ratio in JVS mice was 2.7-fold higher than that in controls (9.9 +/- 0.1 vs. 3.7 +/- 0.1 mg/g, P < 0.01) and was reduced by dietary FO (7.7 +/- 0.1 mg/g, P < 0.01 vs. JVS mice). In JVS mice, myocardial DAG levels were elevated by 2.3-fold with a distinct fatty acid composition with increases in C18:1n-7,9 and C18:2n-6 fatty acids compared with controls; dietary FO had no effects on the total DAG levels but significantly altered the fatty acid composition of DAG with reduction of both fatty acid species. Immunoblot analysis showed that dietary FO prevented the membrane translocation of cardiac PKCs alpha, beta2, and epsilon in JVS mice. Dietary FO did not affect the plasma and myocardial total carnitine levels in JVS mice. Furthermore, dietary FO significantly improved the progressive left ventricular dysfunction and survival rate in JVS mice. CONCLUSIONS: Dietary FO may attenuate cardiac hypertrophy with improvements in cardiac function and survival in JVS mice via modification of the molecular species composition of myocardial DAG and the consequent inhibition of PKC redistribution. These results suggest the implication of the molecular species composition of DAG in the pathogenesis of lipotoxic cardiomyopathy due to perturbations of fatty acid beta-oxidation.
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Yasukatsu Izumi, Shokei Kim-Mitsuyama, Minoru Yoshiyama, Takashi Omura, Masayuki Shiota, Atsushi Matsuzawa, Tokihito Yukimura, Toyoaki Murohara, Motohiro Takeya, Hidenori Ichijo, Junichi Yoshikawa, Hiroshi Iwao (2005)  Important role of apoptosis signal-regulating kinase 1 in ischemia-induced angiogenesis.   Arterioscler Thromb Vasc Biol 25: 9. 1877-1883 Sep  
Abstract: OBJECTIVE: We first examined the role of apoptosis signal-regulating kinase 1 (ASK1), one of mitogen-activated protein kinase kinase kinases, in ischemia-induced angiogenesis. METHODS AND RESULTS: Unilateral hindlimb ischemia was induced surgically in C57BL/6J wild-type (WT) mice or mice deficient in ASK1 (ASK1(-/-)). ASK1 activity in WT mouse hindlimb was increased dramatically after ischemia. By laser Doppler analysis, well-developed collateral vessels and angiogenesis were observed in WT mice in response to hindlimb ischemia, whereas these responses were reduced in ASK1(-/-) mice. Immunostaining revealed that infiltration of macrophages and T lymphocytes was suppressed in the ischemic tissues of ASK1(-/-) mice compared with WT mice. The expression of vascular endothelial growth factor (VEGF) and monocyte chemoattractant protein-1 (MCP-1) proteins in ischemic tissues was weaker in ASK1(-/-) mice compared with WT mice. In vitro study on endothelial cells indicated that dominant-negative ASK1 significantly attenuated hydrogen peroxide-induced VEGF and MCP-1 production. Furthermore, in vivo blockade of MCP-1 by its neutralizing antibody suppressed the recovery of the blood flow and capillary formation after ischemia. CONCLUSIONS: ASK1 pathway promotes early angiogenesis by inducing inflammatory cell infiltration and VEGF and MCP-1 expression. ASK1 may provide the basis for the development of new therapeutic strategy for angiogenesis.
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Maarten B Rookmaaker, Marianne C Verhaar, Cindy J M Loomans, Robert Verloop, Erna Peters, Peter E Westerweel, Toyoaki Murohara, Frank J T Staal, Anton Jan van Zonneveld, Pieter Koolwijk, Ton J Rabelink, Victor W M van Hinsbergh (2005)  CD34+ cells home, proliferate, and participate in capillary formation, and in combination with CD34- cells enhance tube formation in a 3-dimensional matrix.   Arterioscler Thromb Vasc Biol 25: 9. 1843-1850 Sep  
Abstract: OBJECTIVE: Emerging evidence suggests that human blood contains bone marrow (BM)-derived endothelial progenitor cells that contribute to postnatal neovascularization. Clinical trials demonstrated that administration of BM-cells can enhance neovascularization. Most studies, however, used crude cell populations. Identifying the role of different cell populations is important for developing improved cellular therapies. METHODS AND RESULTS: Effects of the hematopoietic stem cell-containing CD34+ cell population on migration, proliferation, differentiation, stimulation of, and participation in capillary-like tubule formation were assessed in an in vitro 3-dimensional matrix model using human microvascular endothelial cells. During movement over the endothelial monolayer, CD34+ cells remained stuck at sites of capillary tube formation and time- and dose-dependently formed cell clusters. Immunohistochemistry confirmed homing and proliferation of CD34+ cells in and around capillary sprouts. CD34+ cells were transduced with the LNGFR marker gene to allow tracing. LNGFR gene-transduced CD34+ cells integrated in the tubular structures and stained positive for CD31 and UEA-1. CD34+ cells alone stimulated neovascularization by 17%. Coculture with CD34- cells led to 68% enhancement of neovascularization, whereas CD34- cells displayed a variable response by themselves. Cell-cell contact between CD34+ and CD34- cells facilitated endothelial differentiation of CD34+ cells. CONCLUSIONS: Our data suggest that administration of CD34+-enriched cell populations may significantly improve neovascularization and point at an important supportive role for (endogenous or exogenous) CD34- cells.
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Satoshi Isobe, Hideo Izawa, Mitsunori Iwase, Mamoru Nanasato, Makoto Nonokawa, Akitada Ando, Satoru Ohshima, Kohzo Nagata, Katsuhiko Kato, Takao Nishizawa, Toyoaki Murohara, Mitsuhiro Yokota (2005)  Cardiac 123I-MIBG reflects left ventricular functional reserve in patients with nonobstructive hypertrophic cardiomyopathy.   J Nucl Med 46: 6. 909-916 Jun  
Abstract: Little is known about the relation between left ventricular (LV) functional reserve in response to exercise and cardiac sympathetic nervous function in patients with nonobstructive hypertrophic cardiomyopathy (HCM). We investigated whether an assessment of cardiac sympathetic nervous function by myocardial (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy might provide a sign of an abnormal LV functional reserve in response to exercise-induced beta-adrenergic stimulation in patients with HCM. METHODS: Thirty HCM patients underwent (123)I-MIBG scintigraphy and echocardiography at rest and subsequent biventricular cardiac catheterization at rest and during dynamic exercise. LV pressures were measured using a micromanometer-tipped catheter system. The early and delayed (123)I-MIBG images were quantified as a heart-to-mediastinum ratio (H/M). The plasma levels of brain natriuretic peptide (BNP) and norepinephrine (NE) were also measured. RESULTS: Patients were divided into 2 groups according to the delayed (123)I-MIBG H/M: group I consisted of 12 patients with a delayed H/M of < or =1.8 and group II had 18 patients with a delayed H/M of >1.8. Both the percentage increase from rest to exercise in LV isovolumic contraction (LV dP/dt(max)) and the percentage shortening of LV pressure half-time (T(1/2)) as an index of isovolumic relaxation were significantly less in group I than in group II (P < 0.05, respectively). A significant linear correlation was observed between the percentage increase in LV dP/dt(max) and (123)I-MIBG H/Ms (early H/M: r = 0.49, P < 0.01; delayed H/M: r = 0.54, P < 0.005, respectively). A significant linear correlation was also observed between the percentage shortening in T(1/2) and (123)I-MIBG H/Ms (early H/M: r = 0.58, P < 0.001; delayed H/M: r = 0.64, P < 0.0005, respectively). The plasma NE levels were significantly higher in group I than in group II (P < 0.01), whereas the plasma BNP levels were comparable in the 2 HCM groups. CONCLUSION: beta-Adrenergic enhancement of LV function during exercise may depend on the extent of cardiac sympathetic nervous innervation in HCM patients. Resting myocardial (123)I-MIBG scintigraphy can noninvasively evaluate LV functional reserve in response to exercise in patients with nonobstructive HCM.
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Shinji Yokoyama, Hisao Ikeda, Nobuya Haramaki, Hideo Yasukawa, Toyoaki Murohara, Tsutomu Imaizumi (2005)  Platelet P-selectin plays an important role in arterial thrombogenesis by forming large stable platelet-leukocyte aggregates.   J Am Coll Cardiol 45: 8. 1280-1286 Apr  
Abstract: OBJECTIVES: We investigated the role of P-selectin in arterial thrombogenesis by forming large stable platelet-leukocyte aggregates. BACKGROUND: Plaque rupture followed by thrombus formation is a fundamental pathophysiology of acute coronary syndromes. Although the adhesive interaction between platelets and leukocytes via P-selectin is known to mediate platelet-rich thrombi, the true function of P-selectin in thrombus formation in vivo is unknown. METHODS: In wild-type (P(+/+)) and P-selectin-deficient (P(-/-)) mice with ferric chloride (FeCl(3))-induced carotid arterial thrombosis model, we measured in vivo platelet P-selectin expression and adenosine diphosphate (ADP)-induced ex vivo platelet aggregation. We also measured ex vivo ADP-induced whole blood aggregations and their size distribution by flow cytometry. RESULTS: Time to thrombotic occlusion was longer in P(-/-) mice than in P(+/+) mice. Spontaneous reflow after total thrombotic occlusion was observed in 8 of 10 P(-/-) mice but not in any P(+/+) mice. ADP-induced ex vivo platelet aggregation was not different between the two groups. However, ADP-induced ex vivo whole blood aggregation was inhibited in P(-/-) mice compared to P(+/+) mice. FeCl(3) application increased in vivo expressions of platelet P-selectin in P(+/+) mice but not in P(-/-) mice. The number of leukocytes within thrombi was less in P(-/-) mice than in P(+/+) mice. In flow cytometric analysis of size distribution of ADP-induced whole blood aggregates, the number of large aggregates was less in P(-/-) mice than in P(+/+) mice. Using platelet and leukocyte fluorescence makers, the large aggregates were confirmed as platelet-leukocyte aggregates. CONCLUSIONS: Platelet P-selectin plays an important role in arterial thrombogenesis by forming large stable platelet-leukocyte aggregates.
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Xian Wu Cheng, Masafumi Kuzuya, Kae Nakamura, Zexuan Liu, Qun Di, Jun Hasegawa, Mitsunaga Iwata, Toyoaki Murohara, Mitsuhiro Yokota, Akihisa Iguchi (2005)  Mechanisms of the inhibitory effect of epigallocatechin-3-gallate on cultured human vascular smooth muscle cell invasion.   Arterioscler Thromb Vasc Biol 25: 9. 1864-1870 Sep  
Abstract: OBJECTIVE: Although we recently showed that the administration of catechins reduced the neointimal formation in a rat balloon-injury model, the precise molecular mechanisms are largely unknown. In the present study, we tried to determine these mechanisms using an in vitro SMC invasion system. METHODS AND RESULTS: Boyden chamber assay was used to examine the effect of catechins on the invasive behavior of SMCs. The invasive activity of SMCs through collagen gel was restrained by EGCG in a concentration-dependent manner. The data from gelatin and collagen zymography and Western blot revealed that EGCG blocks the activation of pro-matrix metalloproteinase (MMP)-2 during an invasion assay and in the conditioned medium of cultured SMCs as well as the activities of MMP-2 and membrane type 1-MMP (MT1-MMP) even at 0.1 to 0.3 micromol/L of EGCG. EGCG was found to restrain MT1-MMPcat-dependent pro-MMP-2 activation. EGCG upregulated the expression of tissue inhibitor of MMP-2 (TIMP-2) protein. Reverse zymography showed that the increased TIMP-2 to expression was validated by an increased activity. The data from decreased TIMP-2 activity using its siRNA suggested that upregulation of TIMP-2 expression may be one of the major mechanisms for inhibition of SMC invasion by EGCG. CONCLUSIONS: These results indicate that EGCG targets multiple MMP-mediated SMC cellular events and provides a new major mechanism for the SMC invasion through upregulation of TIMP-2 expression to modulate MMP activity.
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Takumi Yamada, Yoshimasa Murakami, Masahiro Muto, Taro Okada, Mitsuhiro Okamoto, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Teruo Ito, Takahisa Kondo, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2005)  Computerized three-dimensional potential mapping with a multielectrode basket catheter can be useful for pulmonary vein electrical disconnection.   J Interv Card Electrophysiol 12: 1. 23-33 Jan  
Abstract: INTRODUCTION: Pulmonary vein (PV) isolation (PVI) has been recently proposed as an effective technique to cure atrial fibrillation (AF). AIMS OF THE STUDY: The aim of this study was to investigate the efficacy of a novel technique utilizing a computerized three-dimensional mapping system (QMS2) with a multielectrode basket catheter (MBC) for PVI and to reveal the relation between the style of breakthrough and the network of the PV musculature. METHODS: Sixty-five consecutive patients with frequent AF attacks underwent PV mapping with a 31-mm MBC, and a three-dimensional color animation of the potential map was constructed by the QMS2. The animation color schema was arranged to minimize the low-amplitude left atrial (LA) potentials and emphasize the high-amplitude PV potentials (PVPs). The longitudinal PVP map enabled us to recognize the true breakthroughs and reveal the network of the PV musculature. RESULTS: A total of 205 PVs (65 left superior PVs, 65 right superior PVs, 57 left inferior PVs and 18 right inferior PVs) were mapped and successful PVI was achieved in all PVs, except one that had no PVPs, with a mean radiofrequency duration of 7 +/- 5 minutes per PV. In about 90% of the PVs, a final radiofrequency application eliminated all the distal PVPs simultaneously because the PVI was performed at the appropriate LA-PV junction. A single segmental breakthrough was detected in 17 PVs, single broad breakthrough in 83 PVs, multiple separate breakthroughs with a distal connection between the PV musculatures extending from each separate breakthrough in 88 PVs and multiple separate breakthroughs without that connection in 16 PVs. During the follow-up period, fifty-one (78%) patients were free of symptomatic AF without any antiarrhythmic drugs after multiple procedures (thirty-three (51%) of those patients after the first procedure) and no PV stenosis was found. CONCLUSIONS: Computerized three-dimensional potential mapping can be useful for PVI because it can not only identify the true breakthrough, but can also confirm the elimination of the breakthroughs by the change in the activation sequence through the network of the PV musculature.
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Osamu Yoshida, Haruo Hirayama, Mamoru Nanasato, Toshiya Watanabe, Toyoaki Murohara (2005)  The angiotensin II receptor blocker candesartan cilexetil reduces neointima proliferation after coronary stent implantation: a prospective randomized study under intravascular ultrasound guidance.   Am Heart J 149: 1. Jan  
Abstract: OBJECTIVES: The purpose of this study was to evaluate whether an angiotensin II receptor blocker, candesartan cilexetil, reduced neointima formation after coronary stent implantation by way of serial intravascular ultrasound analysis. BACKGROUND: Previous experimental studies have suggested that angiotensin II receptor blocker reduced neointima formation after vascular injury. However, it is unclear whether candesartan cilexetil has a similar effect on human coronary artery. METHODS: We recruited 50 consecutive patients with stable angina pectoris and 60 stenotic lesions. Patients were prospectively randomized into 2 groups: (1) 25 patients with 31 lesions received candesartan cilexetil (4-12 mg/d), and (2) 25 patients with 29 lesions did not receive the drug. Follow-up intravascular ultrasound was performed 6 m after the stent implantation. Cross-sectional images were obtained at 1-mm intervals within the stent, and the stent volume (SV), lumen volume (LV), and neointima volume (NV = SV - LV) were calculated using Simpson's rule. The percentage neointima volume obstruction (%NV) was calculated as NV/SV x 100. RESULTS: Clinical and angiographic backgrounds were comparable between the 2 groups. At follow-up, the candesartan group had smaller SV and larger LV (SV, 156.3 +/- 53.7 vs 165.4 +/- 61.8 mm3 , ns; LV, 122.2 +/- 49.0 vs 113.1 +/- 45.5 mm3 , ns), and significantly smaller NV and significantly smaller %NV than the control group (NV, 34.2 +/- 16.6 vs 52.3 +/- 32.6 mm3 , P < .01; %NV, 22.7 +/- 10.9% vs 31.3 +/- 13.4%, P < .01). CONCLUSIONS: Candesartan treatment decreases neointima formation and hence may reduce in-stent restenosis.
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Keiko Naruse, Yoji Hamada, Eitaro Nakashima, Koichi Kato, Ryuichi Mizubayashi, Hideki Kamiya, Yukio Yuzawa, Seiichi Matsuo, Toyoaki Murohara, Tatsuaki Matsubara, Yutaka Oiso, Jiro Nakamura (2005)  Therapeutic neovascularization using cord blood-derived endothelial progenitor cells for diabetic neuropathy.   Diabetes 54: 6. 1823-1828 Jun  
Abstract: Diabetic neuropathy is based on the impairment of nerve blood flow and the metabolic disorder. Although the vasodilating agents and anticoagulants improve nerve function and symptoms in diabetic neuropathy, more effective treatments are needed. Because endothelial progenitor cells (EPCs) have been identified in adult human peripheral blood, many studies have shown that transplantation of EPCs improves circulation to ischemic tissues. In this study, we have demonstrated that therapeutic neovascularization using human umbilical cord blood-derived EPCs reversed diabetic neuropathy. EPCs were isolated and expanded on day 7 of culture from cord blood mononuclear cells. Unilateral intramuscular injection of EPCs into hindlimb skeletal muscles significantly ameliorated impaired sciatic motor nerve conduction velocity and sciatic nerve blood flow in the EPC-injected side of streptozotocin-induced diabetic nude rats compared with the saline-injected side of diabetic nude rats. Histological study revealed an increased number of microvessels in hindlimb skeletal muscles in the EPC-injected side of diabetic rats. These findings suggest that transplantation of EPCs from cord blood may be a useful treatment for diabetic neuropathy.
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Koji Obata, Kohzo Nagata, Mitsunori Iwase, Mari Odashima, Tetsuro Nagasaka, Hideo Izawa, Toyoaki Murohara, Yoshiji Yamada, Mitsuhiro Yokota (2005)  Overexpression of calmodulin induces cardiac hypertrophy by a calcineurin-dependent pathway.   Biochem Biophys Res Commun 338: 2. 1299-1305 Dec  
Abstract: The possible role of calcineurin in cardiac hypertrophy induced by calmodulin (CaM) overexpression in the heart was investigated. CaM transgenic (CaM-TG) mice developed marked cardiac hypertrophy and exhibited up-regulation of atrial natriuretic factor (ANF) and beta-myosin heavy chain gene expression in the heart during the first 2 weeks after birth. The activity of calcineurin in the heart was also significantly increased in CaM-TG mice compared with wild-type littermates. Treatment of CaM-TG mice with the calcineurin inhibitor FK506 (1mg/kg per day) prevented the increase in the heart-to-body weight ratio as well as that in cardiomyocyte width. FK506 also inhibited the induction of fetal-type cardiac gene expression in CaM-TG mice. Overexpression of CaM in cultured rat cardiomyocytes activated the ANF gene promoter in a manner sensitive to FK506. Activation of a calcineurin-dependent pathway thus contributes to the development of cardiac hypertrophy induced by CaM overexpression in the heart.
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Michitaka Tsuzuki, Itsuro Morishima, Tomohiro Yoshida, Yuzo Hayashi, Manabu Miura, Toshihisa Hirai, Toru Asai, Yasushi Numaguchi, Takahito Sone, Hideo Matsui, Kenji Okumura, Toyoaki Murohara (2005)  Inverse correlation between soluble CD40 ligand and soluble CD40 is absent in patients with unstable angina.   Heart Vessels 20: 6. 245-250 Nov  
Abstract: The CD40/CD40 ligand (CD40L) system mediates inflammatory processes important in atherogenesis and plaque instability. The expression of CD40L on activated T cells was suppressed by soluble CD40 (sCD40) in vitro. However, the relationship between soluble CD40L (sCD40L) and sCD40 in unstable angina (UA) is still unknown. Thirty-seven consecutive patients with recent chest pain or discomfort were recruited. Patients with both Braunwald's class IB-IIIB and with coronary stenosis (or stenoses) of >75% were assigned to the UA group (n = 19, aged 67.2 +/- 8.2 years), and the rest to the control group (n = 18, aged 63.4 +/- 8.7 years). The serum levels of sCD40L and sCD40, and the plasma levels of matrix metalloproteinase (MMP)-9, were measured by enzyme-linked immunosorbent assays. A significantly inverse correlation between sCD40L and sCD40 was shown in the controls (r = -0.72, P = 0.0007), but was absent in the UA group (r = -0.16, P not significant), although there was no statistical significance between these groups in terms of serum levels of sCD40L or sCD40. The difference of the regression slopes of these regression lines was statistically significant (P < 0.01). Additionally, there was a significant correlation between sCD40 and plasma levels of MMP-9 in the patients with and without UA (r = 0.58, P = 0.0096), but no significant correlation between sCD40L and MMP-9 levels (r = 0.00, P not significant). The balance between CD40 and CD40L may be lost in patients with UA. Soluble CD40 expression may also be related to MMP-9 expression in atherosclerotic tissues.
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Manabu Kokubo, Arata Uemura, Tatsuaki Matsubara, Toyoaki Murohara (2005)  Noninvasive evaluation of the time course of change in cardiac function in spontaneously hypertensive rats by echocardiography.   Hypertens Res 28: 7. 601-609 Jul  
Abstract: The spontaneously hypertensive rat (SHR) has been well established as a suitable model for studies of hypertension, but little is known about the processes of left ventricular (LV) hypertrophy and the changes in cardiac function in this model. The present study was designed to provide a noninvasive evaluation of the time-dependent alteration of cardiac function in male SHR at 4 to 24 weeks of age and age-matched Wistar-Kyoto rats (WKY). Echocardiographic studies were performed after blood pressure (BP) and heart rate (HR) were measured by a tail-cuff method. The body weight (BW) of SHR was lighter than that of WKY at all ages, and HR was consistently lower, with significantly elevated systolic BP from 4 weeks of age. In the echocardiographic study, LV mass at 4 weeks of age was similar between WKY and SHR, although the ratio of LV mass to BW was higher in SHR than WKY. The ejection fraction, fractional shortening (FS) and midwall FS did not differ between the two groups at 4 weeks, but after 8 weeks, these parameters were decreased in the SHR. The deceleration time was prolonged in SHR after 16 weeks and the E/A ratio was lowered at 12 weeks. We also analyzed the expression levels of calcineurin, which were found to be increased in both groups with age. These results suggest that calcineurin does not play a major role in the development of LV hypertrophy. Thus, in SHR, cardiac hypertrophy develops by 4 weeks of age, and systolic and diastolic dysfunction is evident at 2 to 3 months.
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Hideki Ishii, Satoshi Ichimiya, Masaaki Kanashiro, Tetsuya Amano, Kenji Imai, Toyoaki Murohara, Tatsuaki Matsubara (2005)  Impact of a single intravenous administration of nicorandil before reperfusion in patients with ST-segment-elevation myocardial infarction.   Circulation 112: 9. 1284-1288 Aug  
Abstract: BACKGROUND: Intravenous nicorandil, a hybrid compound of ATP-sensitive potassium channel opener and nitric oxide donor, has been reported to ameliorate early functional and clinical problems in patients with acute myocardial infarction. However, its effects on the late phase remain unclear. METHODS AND RESULTS: This follow-up study to 5 years of a randomized, double-blinded trial was conducted among 368 patients with first ST-segment-elevation myocardial infarction undergoing percutaneous coronary intervention (PCI). They were randomly assigned to receive 12 mg of nicorandil or a placebo intravenously just before reperfusion. We analyzed incidence of cardiovascular death or rehospitalization for congestive heart failure after PCI as well as various aspects of epicardial flow and microvascular function. Mean follow-up was 2.4 years (SD, 1.4). A total of 12 (6.5%) patients receiving nicorandil and 30 (16.4%) receiving placebo had cardiovascular death or hospital admission for congestive heart failure (hazard ratio, 0.39; 95% CI, 0.20 to 0.76; P=0.0058). Postprocedural TIMI 3 flow was obtained in 89.7% of the nicorandil group and in 81.4% of the placebo (hazard ratio, 1.99; 95% CI, 1.09 to 3.65; P=0.025). Corrected TIMI frame count was furthermore lower in the nicorandil group (21.0+/-9.1 versus 25.1+/-14.1; P=0.0009). ST-segment resolution >50% was observed in 79.5% and 61.2% of the nicorandil and placebo groups, respectively (hazard ratio, 2.45; 95% CI, 1.54 to 3.90; P=0.0002). CONCLUSIONS: The addition of intravenous nicorandil to PCI leads to beneficial clinical outcomes and prevents cardiovascular events of long duration and death in patients with ST-segment-elevation myocardial infarction.
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Hideo Izawa, Toyoaki Murohara, Kohzo Nagata, Satoshi Isobe, Hiroyuki Asano, Tetsuya Amano, Sahoko Ichihara, Tomoko Kato, Satoru Ohshima, Yosuke Murase, Shigeo Iino, Koji Obata, Akiko Noda, Kenji Okumura, Mitsuhiro Yokota (2005)  Mineralocorticoid receptor antagonism ameliorates left ventricular diastolic dysfunction and myocardial fibrosis in mildly symptomatic patients with idiopathic dilated cardiomyopathy: a pilot study.   Circulation 112: 19. 2940-2945 Nov  
Abstract: BACKGROUND: Mineralocorticoid receptor antagonism reduces mortality associated with heart failure by mechanisms that remain unclear. The effects of the mineralocorticoid receptor antagonist spironolactone on left ventricular (LV) function and chamber stiffness associated with myocardial fibrosis were investigated in mildly symptomatic patients with idiopathic dilated cardiomyopathy (DCM). METHODS AND RESULTS: Twenty-five DCM patients with a New York Heart Association functional class of I or II were examined before and after treatment with spironolactone for 12 months. LV pressures and volumes were measured simultaneously, and LV endomyocardial biopsy specimens were obtained. Serum concentrations of the carboxyl-terminal propeptide (PIP) and carboxyl-terminal telopeptide (CITP) of collagen type I were measured. The patients were divided into 2 groups on the basis of the serum PIP/CITP ratio (< or =35, group A, n=12; >35, group B, n=13), an index of myocardial collagen accumulation. LV diastolic chamber stiffness, the collagen volume fraction, and abundance of collagen type I and III mRNAs in biopsy tissue were greater and the LV early diastolic strain rate (tissue Doppler echocardiography) was smaller in group B than in group A at baseline. These differences and the difference in PIP/CITP were greatly reduced after treatment of patients in group B with spironolactone, with treatment having no effect on these parameters in group A. The collagen volume fraction was significantly correlated with PIP/CITP, LV early diastolic strain rate, and LV diastolic chamber stiffness for all patients before and after treatment with spironolactone. CONCLUSIONS: Spironolactone ameliorated LV diastolic dysfunction and reduced chamber stiffness in association with regression of myocardial fibrosis in mildly symptomatic patients with DCM. These effects appeared limited, however, to patients with increased myocardial collagen accumulation.
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Satoru Ohshima, Satoshi Isobe, Hideo Izawa, Mamoru Nanasato, Akitada Ando, Akira Yamada, Kiyoyasu Yamada, Tomoko S Kato, Koji Obata, Akiko Noda, Takao Nishizawa, Katsuhiko Kato, Kohzo Nagata, Kenji Okumura, Toyoaki Murohara, Mitsuhiro Yokota (2005)  Cardiac sympathetic dysfunction correlates with abnormal myocardial contractile reserve in dilated cardiomyopathy patients.   J Am Coll Cardiol 46: 11. 2061-2068 Dec  
Abstract: OBJECTIVES: We investigated the relationship between iodine-123-metaiodobenzylguanidine (123I-MIBG) findings and myocardial contractile reserve in patients with mild to moderate dilated cardiomyopathy (DCM). BACKGROUND: Little is known regarding the relationship between cardiac sympathetic nervous function and myocardial contractile reserve in DCM. METHODS: Twenty-four DCM patients who showed sinus rhythm underwent echocardiography, biventricular catheterization, and myocardial 123I-MIBG scintigraphy. Left ventricular (LV) pressures were measured using a micromanometer-tipped catheter. The myocardial contractile function (LV dP/dt(max)) was determined at rest and during atrial pacing. The messenger ribonucleic acid (mRNA) expressions of intracellular Ca2+-regulatory proteins were analyzed by real-time quantitative reverse transcription-polymerase chain reaction. Myocardial 123I-MIBG accumulation was quantified as a heart-mediastinum ratio (HMR). RESULTS: A significant correlation was observed between the delayed 123I-MIBG HMR and the percentage change in LV dP/dt(max) from the baseline to the peak or critical heart rate (r = 0.64; p < 0.001). The delayed 123I-MIBG HMR was significantly lower in patients showing a worsening change in LV dP/dt(max) than in those showing a favorable change (p < 0.005). The maximum LV dP/dt(max) during pacing and the sarcoplasmic reticulum Ca2+-ATPase (SERCA2) mRNA levels were significantly more reduced in patients with a delayed HMR < or =1.8 than in those with a delayed HMR >1.8 (p < 0.05, respectively). CONCLUSIONS: Abnormal myocardial 123I-MIBG accumulation is related to an impaired myocardial contractile reserve and down-regulation of SERCA2 mRNA in DCM. Myocardial 123I-MIBG scintigraphy can be useful in noninvasively evaluating myocardial contractile reserve in patients with mild to moderate DCM.
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Mejeong Lee, Mika Aoki, Takahisa Kondo, Koichi Kobayashi, Kenji Okumura, Kimihiro Komori, Toyoaki Murohara (2005)  Therapeutic angiogenesis with intramuscular injection of low-dose recombinant granulocyte-colony stimulating factor.   Arterioscler Thromb Vasc Biol 25: 12. 2535-2541 Dec  
Abstract: OBJECTIVE: In vivo administration of granulocyte colony-stimulating factor (G-CSF) has been shown to facilitate regeneration of cardiovascular tissues. However, G-CSF causes marked leukocytosis that potentially induces adverse cardiovascular events. Earlier studies showed that G-CSF had direct stimulatory actions on mature endothelial cells, resulting in promotion of angiogenesis. We thus examined whether low doses of recombinant human G-CSF (rhG-CSF) locally injected into ischemic tissues would stimulate angiogenesis without inducing severe leukocytosis. METHODS AND RESULTS: Reverse-transcription polymerase chain reaction (PCR) revealed expression of G-CSF receptor in human umbilical vein endothelial cells (HUVECs). rhG-CSF (100 ng/mL) enhanced migration and tube formation but not proliferation of HUVECs in vitro. We then examined the effects of rhG-CSF on angiogenesis in a rat model of hindlimb ischemia. Nude rats received in their ischemic skeletal muscles either rhG-CSF (2, 10, 20 microg/kg per day) or saline (control) for 6 days. Laser Doppler blood flowmetry (LDBF) revealed an augmented ischemic/normal limb LDBF ratio and an increased capillary density in the rhG-CSF-treated groups compared with the control at days 14, 21, and 28 (P<0.05). These doses of rhG-CSF induced only mild leukocytosis ( approximately 1.4-fold increases versus baseline). CONCLUSIONS: rhG-CSF promoted endothelial migration and tube formation in vitro. Local injection of low doses rhG-CSF effectively augmented ischemia-induced angiogenesis in vivo. This treatment regimen of low-dose rhG-CSF may become a new and safe modality for therapeutic angiogenesis.
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Jinglan Xu, Kohzo Nagata, Koji Obata, Sahoko Ichihara, Hideo Izawa, Akiko Noda, Tetsuro Nagasaka, Mitsunori Iwase, Tomoki Naoe, Toyoaki Murohara, Mitsuhiro Yokota (2005)  Nicorandil promotes myocardial capillary and arteriolar growth in the failing heart of Dahl salt-sensitive hypertensive rats.   Hypertension 46: 4. 719-724 Oct  
Abstract: Long-term administration of vasodilators increases shear stress, which is thought to be important for vascular growth in the heart. Nicorandil, an activator of ATP-sensitive potassium channels with a nitrate-like action, is a potent vasodilator. We have now investigated the effects of nicorandil on vascular growth and gene expression in the failing heart of Dahl salt-sensitive (DS) hypertensive rats. DS rats fed a high-salt diet from 6 weeks of age develop concentric cardiac hypertrophy secondary to hypertension at 11 weeks, followed by heart failure at 18 weeks. DS rats on such a diet were treated with a nonantihypertensive oral dose of nicorandil (6 mg/kg per day) or vehicle from 11 to 18 weeks of age. Treatment of DS rats with nicorandil improved cardiac function and attenuated the development of heart failure. Myocardial capillary and arteriolar densities did not differ between vehicle-treated DS rats and age-matched controls. The abundance of mRNAs for endothelial NO synthase (eNOS), vascular endothelial growth factor (VEGF), the VEGF receptor Flt-1, and basic fibroblast growth factor (bFGF) in the myocardium was markedly reduced in vehicle-treated DS rats compared with controls. Treatment of DS rats with nicorandil greatly increased capillary and arteriolar densities and inhibited the downregulation of eNOS, VEGF, fms-like tyrosin kinase-1, and bFGF gene expression. This, nicorandil stimulates coronary capillary and arteriolar growth and thereby likely suppresses the development of heart failure in DS rats. Nicorandil may prove beneficial for the treatment of hypertensive heart failure as well as of ischemic heart disease.
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Yosuke Murase, Yoshiji Yamada, Akihiro Hirashiki, Sahoko Ichihara, Hirofumi Kanda, Masato Watarai, Fumimaro Takatsu, Toyoaki Murohara, Mitsuhiro Yokota (2004)  Genetic risk and gene-environment interaction in coronary artery spasm in Japanese men and women.   Eur Heart J 25: 11. 970-977 Jun  
Abstract: AIMS: The aim of the study was to identify genes that confer susceptibility to coronary artery spasm and clarify the interaction between genetic and environmental factors in this condition. METHODS AND RESULTS: The study population comprised 2188 Japanese individuals, including 593 subjects with coronary artery spasm (453 men, 140 women) and 1595 controls (762 men, 833 women). The genotypes for 35 polymorphisms of 29 candidate genes were determined with an allele-specific DNA primer-probe assay. Multivariable logistic regression analysis adjusted for age, body mass index, and the prevalence of smoking, hypertension, diabetes mellitus, hypercholesterolaemia, and hyperuricaemia revealed a significant association with coronary artery spasm of one polymorphism (242C-->T in the NADH/NADPH oxidase p22 phox gene) in men and two polymorphisms (-1171/5A-->6A in the stromelysin-1 gene and -634C-->G in the interleukin-6 gene) in women. A stepwise forward selection procedure revealed that smoking was the most important risk factor for coronary artery spasm and that the effects of these polymorphisms on this condition were statistically independent of smoking. CONCLUSION: The NADH/NADPH oxidase p22 phox gene is a susceptibility locus for coronary artery spasm in men, and the stromelysin-1 and interleukin-6 genes are susceptibility loci in women.
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Hideo Izawa, Yoshiji Yamada, Toro Okada, Masashi Tanaka, Haruo Hirayama, Toyoaki Murohara, Mitsuhiro Yokota (2004)  Prediction of genetic risk for hypertension   J Cardiol 43: 2. 92-93 Feb  
Abstract: BACKGROUND: Although genetic epidemiological studies have suggested that several genetic variants increase the risk for hypertension, the genes that underlie genetic susceptibility to this condition remain to be identified definitively. Large-scale association studies that examine many gene polymorphisms simultaneously are required to predict genetic risk for hypertension. METHODS and RESULTS: The population of the present study comprised 1,940 unrelated Japanese individuals, including 1,067 subjects with hypertension (574 men, 493 women) and 873 controls (533 men, 340 women). The genotypes for 33 single nucleotide polymorphisms of 27 candidate genes were determined with a fluorescence- or colorimetry-based allele-specific DNA primer-probe assay system. Multivariate logistic regression analysis with adjustment for age, body mass index, and the prevalence of smoking, diabetes mellitus, hypercholesterolemia, and hyperuricemia revealed that two polymorphisms (825C -> T in the G protein beta3 subunit gene and 190G -> A in the CC chemokine receptor 2 gene) were significantly associated with hypertension in men and that one polymorphism (-238G -> A in the tumor necrosis factor- alpha gene) was significantly associated with hypertension in women. CONCLUSION: These results suggest that two and one genes may be susceptibility loci for hypertension in Japanese men and women, respectively, and that genotyping of these polymorphisms may prove informative for prediction of the genetic risk for hypertension.
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Kyosuke Takeshita, Toshihiko Fujimori, Yoko Kurotaki, Haruo Honjo, Hiroshi Tsujikawa, Kenji Yasui, Jong-Kook Lee, Kaichiro Kamiya, Kiyoyuki Kitaichi, Koji Yamamoto, Masafumi Ito, Takahisa Kondo, Shigeo Iino, Yasuya Inden, Makoto Hirai, Toyoaki Murohara, Itsuo Kodama, Yo-ichi Nabeshima (2004)  Sinoatrial node dysfunction and early unexpected death of mice with a defect of klotho gene expression.   Circulation 109: 14. 1776-1782 Apr  
Abstract: BACKGROUND: Homozygous mutant mice with a defect of klotho gene expression (kl/kl) show multiple age-related disorders and premature death from unknown causes. METHODS AND RESULTS: The kl/kl mice subjected to 20-hour restraint stress showed a high rate (20/30) of sudden death, which was associated with sinoatrial node dysfunction (conduction block or arrest). Heart rate and plasma norepinephrine of kl/kl mice, unlike those of wild-type (WT) mice, failed to increase during the stress. Intrinsic heart rate after pharmacological blockade of autonomic nerves in kl/kl mice was significantly lower than that in WT mice (380+/-33 versus 470+/-44 bpm; n=7). The sinus node recovery time after an overdrive pacing (600 bpm, 30 seconds) in kl/kl mice was significantly longer than in WT mice (392+/-37 versus 233+/-24 ms; n=6). In isolated sinoatrial node preparations, the positive chronotropic effect of isoproterenol was significantly less, whereas the negative chronotropic effect of acetylcholine was significantly greater in kl/kl than in WT mice. There was no degenerative structural change in the sinoatrial node of kl/kl mice. The precise localization of klotho was analyzed in newly prepared klotho-null mice with a reporter gene system (kl(-geo)). Homozygous kl(-geo) mice showed characteristic age-associated phenotypes that were almost identical to those of kl/kl mice. In the kl(-geo) mice, klotho expression was recognized exclusively in the sinoatrial node region in the heart in addition to parathyroid, kidney, and choroid plexus. CONCLUSIONS: In the heart, klotho is expressed solely at the sinoatrial node. klotho gene expression is essential for the sinoatrial node to function as a dependable pacemaker under conditions of stress.
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Takahisa Kondo, Mutsuharu Hayashi, Kyosuke Takeshita, Yasushi Numaguchi, Koichi Kobayashi, Shigeo Iino, Yasuya Inden, Toyoaki Murohara (2004)  Smoking cessation rapidly increases circulating progenitor cells in peripheral blood in chronic smokers.   Arterioscler Thromb Vasc Biol 24: 8. 1442-1447 Aug  
Abstract: OBJECTIVE: Circulating endothelial progenitor cells (EPCs) contribute to postnatal angiogenesis. The number of circulating EPCs has an inverse correlation with coronary risk scores. However, the effect of smoking on the number of circulating EPCs is not well-known. METHODS AND RESULTS: We examined the effects of chronic smoking and of smoking cessation on EPC levels. Circulating EPCs were quantified by flow cytometry as CD45lowCD34+CD133+ (progenitor cells [PCs]) or CD45lowCD34+CD133+VEGFR2+ (EPCs) in 14 nonsmokers and in 15 smokers. All smokers quit smoking. Eight quit smoking with nicotine patch and 7 without nicotine patch. PC/EPC levels were inversely correlated with the number of cigarettes smoked. Circulating PCs/EPCs increased rapidly after cessation (P<0.0001) and decreased again after resumption of smoking to the level similar to that before cessation (P=0.0031). The magnitude of increase in EPCs was greater in light smokers than in heavy smokers. CONCLUSIONS: The number of circulating PCs/EPCs was reduced in chronic smokers. Smoking cessation led to a rapid restoration of PC/EPC levels. The recovery of EPC levels was greater in light smokers than in heavy smokers. The decreased number of circulating EPCs would make smokers susceptible to cardiovascular disease, and even short-time cessation of smoking may be an effective means to reduce cardiovascular risk.
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Toyoaki Murohara, Hisao Ikeda, Yoritaka Otsuka, Mika Aoki, Nobuya Haramaki, Atsushi Katoh, Yoshinori Takajo, Tsutomu Imaizumi (2004)  Inhibition of platelet adherence to mononuclear cells by alpha-tocopherol: role of P-selectin.   Circulation 110: 2. 141-148 Jul  
Abstract: BACKGROUND: Platelet-leukocyte interaction is an early important event for thrombogenesis, and this process is mainly mediated by P-selectin on platelets. Although alpha-tocopherol has been shown to inhibit thrombotic disorders, the effect of alpha-tocopherol on platelet P-selectin expression and platelet-leukocyte interaction is little known. METHODS AND RESULTS: We examined whether alpha-tocopherol inhibited human platelet P-selectin expression and platelet-leukocyte interaction. Alpha-tocopherol (50 to 500 microg/mL) inhibited thrombin-induced or phorbol 12-myristate 13-acetate (PMA)-induced P-selectin expression on platelets. alpha-Tocopherol suppressed platelet-mononuclear cell (MNC) interaction, platelet aggregation, and platelet protein kinase C (PKC) activity stimulated with either PMA (100 nmol/L) or thrombin. Inhibitory actions of alpha-tocopherol against the platelet functions were mimicked by staurosporine, a selective PKC inhibitor. After oral supplementation of alpha-tocopherol (300 mg/d for 3 weeks) in healthy subjects, thrombin-mediated or PMA-mediated P-selectin expression, platelet-MNC interaction, and platelet aggregation ex vivo were suppressed. CONCLUSIONS: alpha-Tocopherol inhibited P-selectin expression on human platelets and thereby attenuated platelet-MNC interactions, which were mediated at least in part by the inhibition of intraplatelet PKC activity. These actions of alpha-tocopherol on platelet functions provide new insights into the antithromboatherogenic properties of alpha-tocopherol.
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Tomoko Kato, Michael C Y Chan, Shao-Zhou Gao, John S Schroeder, Mitsuhiro Yokota, Toyoaki Murohara, Mitsunori Iwase, Akiko Noda, Sharon A Hunt, Hannah A Valantine (2004)  Glucose intolerance, as reflected by hemoglobin A1c level, is associated with the incidence and severity of transplant coronary artery disease.   J Am Coll Cardiol 43: 6. 1034-1041 Mar  
Abstract: OBJECTIVES: The possible effect of plasma hemoglobin A(1c) (HbA(1c)) on the development of transplant coronary artery disease (TxCAD) was investigated. BACKGROUND: Glucose intolerance is implicated as a risk factor for TxCAD. However, a relationship between HbA(1c) and TxCAD has not been demonstrated. METHODS: Plasma HbA(1c) was measured in 151 adult patients undergoing routine annual coronary angiography at a mean period of 4.1 years after heart transplantation. Intracoronary ultrasound (ICUS) was also performed in 42 patients. Transplant CAD was graded by angiography as none, mild (stenosis in any vessel < or =30%), moderate (31% to 69%), or severe (> or =70%) and was defined by ICUS as a mean intimal thickness (MIT) > or =0.3 mm in any coronary artery segment. The association between TxCAD and established risk factors was examined. RESULTS: Plasma HbA(1c) increased with the angiographic grade of TxCAD (5.6%, 5.8%, 6.4%, and 6.2% for none, mild, moderate, and severe disease, respectively; p < 0.05 for none vs. moderate or severe) and correlated with disease severity (r = 0.24, p < 0.05). The HbA(1c) level was higher in patients with MIT > or =0.3 mm than in those with MIT <0.3 mm (6.4% vs. 5.7%, p < 0.05). Multivariate logistic regression analysis identified HbA(1c) as an independent predictor of TxCAD, as detected by angiography or ICUS (odds ratios 1.9 and 2.4, 95% confidence intervals 1.5 to 6.3 [p = 0.010] and 1.3 to 4.2 [p < 0.005], respectively). CONCLUSIONS: Persistent glucose intolerance, as reflected by plasma HbA(1c), is associated with the occurrence of TxCAD and may play an important role in its pathogenesis.
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Kiyoyasu Yamada, Makoto Hirai, Kazunari Abe, Hitoshi Ishihara, Kyosuke Takeshita, Yasunobu Takada, Masahiro Mutoh, Hironori Noda, Atsuya Shimizu, Yoshihisa Shibata, Takumi Yamada, Takahisa Kondo, Yukihiko Yoshida, Yasuya Inden, Toyoaki Murohara (2004)  Diagnostic usefulness of postexercise systolic blood pressure response for detection of coronary artery disease in patients with echocardiographic left ventricular hypertrophy.   Can J Cardiol 20: 7. 705-711 May  
Abstract: BACKGROUND: Although exercise-induced electrocardiographic ST segment changes are used to detect coronary artery disease (CAD), their diagnostic value is markedly decreased in patients with left ventricular (LV) hypertrophy. There have been no reports concerning postexercise systolic blood pressure (SBP) response in patients with ultrasound echocardiographic (UCG) LV hypertrophy and CAD. METHODS: Sixty-six patients with both UCG-LV hypertrophy (LV mass index 134 g/m2 or greater for men or 110 g/m2 or greater for women) and positive ST depression of at least 0.1 mV during treadmill exercise testing were studied. Coronary cineangiograms showed normal coronary arteries in 19 patients (group 1) and significant CAD in 47 patients (group 2). The SBP ratio was calculated by dividing the SBP 3 min after exercise (3 min SBP) by the SBP at peak exercise (peak SBP). RESULTS: There were no significant differences between the two groups in LV mass index, SBP at rest, exercise duration, ST depression (at rest and exercise-induced) or 3 min SBP. However, the SBP ratio was significantly higher in group 2 compared with group 1 (0.87+/-0.11 versus 1.01+/-0.18; P=0.004). Analysis of relative cumulative frequency distributions revealed an SBP ratio of 0.92 as the cutoff point for distinguishing a UCG-LV hypertrophy patient with CAD from one without CAD. The sensitivity, specificity and accuracy with an SBP ratio of 0.92 and an ST segment depression of at least 0.1 mV on treadmill exercise testing for detecting CAD in patients with UCG-LV hypertrophy were 77%, 74% and 76%, respectively. CONCLUSION: These findings suggest that the ratio of early post-exercise SBP to peak exercise SBP may be diagnostically useful in detecting CAD in patients with positive ST depression during an exercise test and UCG-LV hypertrophy.
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Akira Yamada, Sahoko Ichihara, Yosuke Murase, Tomoko Kato, Hideo Izawa, Kohzo Nagata, Toyoaki Murohara, Yoshiji Yamada, Mitsuhiro Yokota (2004)  Lack of association of polymorphisms of the lymphotoxin alpha gene with myocardial infarction in Japanese.   J Mol Med 82: 7. 477-483 Jul  
Abstract: Vascular inflammation plays an important role in the development of myocardial infarction (MI). Lymphotoxin alpha (LTA) is a cytokine with multiple functions in regulation of the immune system and inflammatory reactions. The aim of this study was to examine whether polymorphisms of the LTA gene are associated with the risk of MI in Japanese men and women. A case-control association study was performed for the 252A-->G and 804C-->A polymorphisms of the LTA gene and the prevalence of MI. The study population comprised 3,689 unrelated Japanese individuals (2,486 men, 1,203 women), including 1891 patients with MI (1,493 men, 398 women) and 1798 control subjects (993 men, 805 women). Among the control subjects 257 individuals (108 men, 149 women) who had none of the conventional risk factors for coronary artery disease (CAD) were defined as low-risk controls. Genotypes for the two polymorphisms were determined with a fluorescence-based allele-specific DNA primer assay system. Among all study subjects the 252A-->G and 804C-->A polymorphisms exhibited linkage disequilibrium. No association of either polymorphism with MI was detected in men or in women in comparisons with total control or low-risk control subjects. However, each of the two polymorphisms was associated with the prevalence of type 2 diabetes mellitus both in men with MI and in those without MI in a recessive genetic model. No association was detected between the polymorphisms and other conventional risk factors for CAD. The LTA gene thus does not appear to be a susceptibility locus for MI in Japanese men or women, although it might affect susceptibility to type 2 diabetes in Japanese men.
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Yasushi Numaguchi, Kenji Okumura, Mitsunori Harada, Keiji Naruse, Michiharu Yamada, Hiroyuki Osanai, Hideo Matsui, Masafumi Ito, Toyoaki Murohara (2004)  Catheter-based prostacyclin synthase gene transfer prevents in-stent restenosis in rabbit atheromatous arteries.   Cardiovasc Res 61: 1. 177-185 Jan  
Abstract: OBJECTIVE: Prostacyclin synthase (PGIS) gene transfer have been shown to accelerate re-endothelialization and prevent neointimal formation in balloon-injured arteries. The aim of this study is to evaluate how overexpression of endogenous prostacyclin exerts those beneficial effects in atheromatous arteries. METHODS: New Zealand White Rabbits fed a 0.5% cholesterol diet underwent balloon injury and Palmaz-Schatz stent implantation in the iliac arteries followed PGIS gene (pCMV-PGIS, 200 microg) delivery by the lipotransfection method via Dispatch catheter (n=6 each). RESULTS: One week after transfection, arterial segments of pCMV-PGIS produced higher levels of 6-keto-PGF1alpha than those of control, pCMV-LacZ (p<0.05). The levels of vascular endothelial growth factor (VEGF) expression was greater in the vessels of pCMV-PGIS than in those of pCMV-LacZ demonstrated by immunohistochemical analysis and quantitation of Western blotting (1.8-fold, p<0.05). At 2 weeks, in-stent endothelialization was significantly greater in the vessels of pCMV-PGIS than in those of pCMV-LacZ (p<0.01). The percentage of BrdU-positive nuclei in the injured arterial segments was lower in vessels of pCMV-PGIS than pCMV-LacZ (p<0.01). At 4 weeks, PGIS gene transfer reduced the neointimal area by 38% (p<0.05) and widened the lumen area by 71% (p<0.01). CONCLUSION: PGIS gene transfer accelerated re-endothelialization, and attenuated neointimal formation after stent implantation in atheromatous rabbit arteries, at least in part, via increased production of VEGF protein.
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Mamoru Nanasato, Haruo Hirayama, Akitada Ando, Satoshi Isobe, Makoto Nonokawa, Yoshimi Kinoshita, Ichiro Nanbu, Mitsuhiro Yokota, Toyoaki Murohara (2004)  Incremental predictive value of myocardial scintigraphy with 123I-BMIPP in patients with acute myocardial infarction treated with primary percutaneous coronary intervention.   Eur J Nucl Med Mol Imaging 31: 11. 1512-1521 Nov  
Abstract: PURPOSE: It is unclear whether 123I-labelled beta-methyl iodophenyl pentadecanoic acid (123I-BMIPP) myocardial scintigraphy adds further predictive value for future cardiac events compared with the variables obtained during cardiac catheterisation in patients with acute myocardial infarction (AMI) treated with primary percutaneous coronary intervention (PCI). We therefore investigated whether 123I-BMIPP imaging in patients with AMI treated by primary PCI was useful in predicting future cardiac events. METHODS: One hundred and fifty-nine patients with AMI who were treated with primary PCI and underwent left ventriculography (LVG) on admission underwent 201Tl and 123I-BMIPP myocardial scintigraphy. Scintigrams were visually classified, and the total defect score (TDS) was calculated. Major adverse cardiac events (MACE) were defined as cardiac death including sudden death, congestive heart failure and recurrence of acute coronary syndrome. Patients were followed up for a mean of 34.5 months (12-63 months). RESULTS: Twenty-six patients had MACE. Kaplan-Meier analysis indicated that patients with the top 50% of 123I-BMIPP TDSs had a significantly higher rate of MACE (P=0.007). Patients with mismatch between 201Tl and 123I-BMIPP images also had significantly more MACE (P=0.02). In the prediction of MACE, the global chi-square value was 5.2 (P=0.001) based on LVEF (<45%) and the number of diseased vessels (two or three). Adding 123I-BMIPP TDS and the mismatch improved the global chi-square value (chi2=7.2) CONCLUSION: Myocardial scintigraphy using 201Tl and 123I-BMIPP predicts future cardiac events in patients with AMI treated with primary PCI, and provides additional predictive value compared with the variables obtained with cardiac catheterisation alone.
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Hisashi Umeda, Mitsunori Iwase, Hirohumi Kanda, Hideo Izawa, Kohzo Nagata, Ryoji Ishiki, Ken Sawada, Toyoaki Murohara, Mitsuhiro Yokota (2004)  Promising efficacy of primary gradual and prolonged balloon angioplasty in small coronary arteries: a randomized comparison with cutting balloon angioplasty and conventional balloon angioplasty.   Am Heart J 147: 1. Jan  
Abstract: BACKGROUND: Small vessel size represents a critical risk factor for an adverse outcome after both conventional balloon angioplasty (POBA) and stenting. Gradual and prolonged balloon angioplasty (GPBA) has been shown to cause less arterial trauma, which results in higher procedural success rates and fewer in-hospital complications than POBA. The aim of this study was to assess the clinical and angiographic benefits of primary GPBA with a perfusion balloon in small coronary arteries, as compared with cutting balloon angioplasty (CBA) and POBA. METHODS: A total of 263 patients with symptoms and reference diameters <3.0 mm were randomly assigned to undergo GPBA (n = 85), CBA (n = 88), or POBA (n = 90). The cumulative inflation time must be >10 minutes in GPBA. Crossover to stent was allowed for inadequate results. Follow-up angiography was performed after 6 months. The primary end point was angiographic restenosis at follow-up. RESULTS: Compared with POBA, GPBA resulted in a lower final residual diameter stenosis (27.3% vs 34.2%, P =.01) and decreased the need for stent placement (8.0% vs 22.2%, P =.031). At follow-up, the restenosis rates were lower with GPBA (31.3%, P =.034) and CBA (32.9%, P =.059) than POBA (50.6%). Target lesion revascularization was less frequently needed with GPBA (20.5%, P =.043) and CBA (20.0%, P =.033) than POBA (37.6%). Additionally, the event-free survival rate was higher with GPBA (77.1%, P =.033) and CBA (76.4%, P =.047) than POBA (58.8%). CONCLUSIONS: In small coronary arteries, both GPBA and CBA resulted in favorable angiographic and clinical outcomes. With a lower restenosis rate and target lesion revascularization rate, GPBA may be a superior strategy for small vessels compared with POBA.
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Koichi Asaba, Yasumasa Iwasaki, Masanori Yoshida, Masato Asai, Yutaka Oiso, Toyoaki Murohara, Kozo Hashimoto (2004)  Attenuation by reactive oxygen species of glucocorticoid suppression on proopiomelanocortin gene expression in pituitary corticotroph cells.   Endocrinology 145: 1. 39-42 Jan  
Abstract: Up-regulation of hypothalamo-pituitary-adrenal axis is maintained during acute inflammation and/or infection, in the face of sustained elevation of plasma glucocorticoid hormone. Inflammatory stress is usually associated with high plasma cytokine levels and increased generation of reactive oxygen species (ROS) as well. In this study, we examined the effect of ROS on the negative feedback regulation of glucocorticoid in hypothalamo-pituitary-adrenal axis using AtT20 corticotroph cells in vitro. When the cells were treated with H2O2, glucocorticoid suppression on the proopiomelanocortin gene promoter activity was attenuated in a dose-dependent manner. H2O2 also inhibited the ligand-stimulated nuclear translocation of glucocorticoid receptor. The released glucocorticoid suppression by H2O2 was not observed when the cells were cotreated with antioxidants. Together, these results suggest that increased ROS generation in the oxidative redox state attenuates the glucocorticoid negative feedback system, at least in part, by interfering with the nuclear translocation of glucocorticoid receptor and eliminating the repression on proopiomelanocortin gene expression.
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Keiko Shimokata, Yoshiji Yamada, Takahisa Kondo, Sahoko Ichihara, Hideo Izawa, Kohzo Nagata, Toyoaki Murohara, Miyoshi Ohno, Mitsuhiro Yokota (2004)  Association of gene polymorphisms with coronary artery disease in individuals with or without nonfamilial hypercholesterolemia.   Atherosclerosis 172: 1. 167-173 Jan  
Abstract: A substantial proportion of individuals with coronary artery disease (CAD) has concomitant hypercholesterolemia. A large-scale association study was performed to identify separately genes that confer susceptibility to CAD in the absence or presence of nonfamilial hypercholesterolemia. The study population comprised 5248 unrelated Japanese individuals, including 3085 subjects with CAD (2350 men, 735 women) and 2163 controls (1329 men, 834 women). Among all study subjects, 2541 individuals (1688 men, 853 women) had nonfamilial hypercholesterolemia, and 2707 individuals (1991 men, 716 women) did not have this condition. The genotypes for 33 polymorphisms of 27 candidate genes were determined with a fluorescence- or colorimetry-based allele-specific DNA primer-probe assay system. Multivariate logistic regression analysis with adjustment for age, body mass index, and the prevalence of smoking, hypertension, diabetes mellitus, and hyperuricemia revealed that three polymorphisms [994G --> T (Val279Phe) in the platelet-activating factor acetylhydrolase gene, 242C --> T (His72Tyr) in the NADH/NADPH oxidase p22 phox gene, and 1100C --> T in the apolipoprotein C-III gene] were significantly associated with CAD in men with hypercholesterolemia. Genotyping of these three polymorphisms may prove informative for prediction of the genetic risk for CAD in men with nonfamilial hypercholesterolemia.
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Kyosuke Takeshita, Mutsuharu Hayashi, Shigeo Iino, Takahisa Kondo, Yasuya Inden, Mitsunori Iwase, Tetsuhito Kojima, Makoto Hirai, Masafumi Ito, David J Loskutoff, Hidehiko Saito, Toyoaki Murohara, Koji Yamamoto (2004)  Increased expression of plasminogen activator inhibitor-1 in cardiomyocytes contributes to cardiac fibrosis after myocardial infarction.   Am J Pathol 164: 2. 449-456 Feb  
Abstract: Plasminogen activator inhibitor-1 (PAI-1) plays a critical role in tissue fibrosis by inactivating matrix metalloproteinases, which might effect on the progression of left ventricular dysfunction. However, little has been known about the expression of PAI-1 during cardiac remodeling. We used a mouse model of myocardial infarction (MI) by coronary ligation, in which the progression of left ventricular remodeling was confirmed by echocardiography. Histological examination showed that interstitial and perivascular fibrosis progressed in the post-MI (PMI) heart at 4 weeks after the procedure. We observed the dramatic induction of cardiac PAI-1 mRNA and PAI-1 antigen in plasma in the PMI mice, as compared with the sham-operated (sham) mice. In situ hybridization analysis demonstrated that strong signals for PAI-1 mRNA were localized to cardiomyocytes in the border of infarct area and around fibrous lesions, and to perivascular mononuclear cells, which seemed to be mast cells, only in hearts of the PMI mice. Importantly, less development of cardiac fibrosis after MI was observed in mice deficient in PAI-1 as compared to wild-type mice. The mRNA expression of cytokines, transforming growth factor-beta, and tumor necrosis factor-alpha, was also increased in hearts of the PMI mice, but not in the sham mice. These observations suggest that cardiomyocytes and mast cells contribute to the increased PAI-1 expression, resulting in the development of interstitial and perivascular fibrosis in the PMI heart, and that the regional induction of cytokines may be involved in this process.
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Tadayuki Uetani, Hideki Ishii, Shin-ichi Sakai, Junji Watanabe, Masaaki Kanashiro, Satoshi Ichimiya, Toyoaki Murohara, Tatsuaki Matsubara (2004)  Beneficial effect of rotational atherectomy with low platform speed on late outcomes.   Int J Cardiol 94: 1. 35-40 Mar  
Abstract: BACKGROUND: Modification of rotational atherectomy (RA) procedures might be expected to alter restenosis rates. METHODS AND RESULTS: From June 1998 (period 2), platform speed was decreased to 150,000-160,000 rpm from the 170,000-190,000 rpm performed from August 1997 to May 1998 (period 1). Patients for the two periods (period 1: 62 patients, 70 lesions; period 2: 85 patients, 91 lesions) demonstrated comparable clinical and angiographic baseline data, allowing immediate and late outcomes to be evaluated for comparison. Restenosis rates in periods 1 and 2 were 57.9% and 33.8%, respectively (P=0.01). Platform speed and lesion length were independent predictors of restenosis by multivariate logistic regression analysis. CONCLUSIONS: RA with a low platform speed (150,000-160,000 rpm) can be performed with a high success rate and with a lower incidence of restenosis than with a high platform speed (170,000-190,000 rpm).
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Noriyuki Suzuki, Yoshihisa Shibata, Takeshi Urano, Toyoaki Murohara, Takashi Muramatsu, Kenji Kadomatsu (2004)  Proteasomal degradation of the nuclear targeting growth factor midkine.   J Biol Chem 279: 17. 17785-17791 Apr  
Abstract: It is widely held that growth factor signaling is terminated by lysosomal degradation of its activated receptor and the endocytosed growth factor is transported to lysosomes. Nuclear targeting is another important pathway through which signals of growth factors are mediated. However, mechanisms underlying desensitization of nuclear targeting growth factors are poorly understood. Here we report that the nuclear targeting pathway is down-regulated by the proteasome system. Degradation of endocytosed midkine, a heparin-binding growth factor, was suppressed by both proteasome and lysosome inhibitors to similar extents. By contrast, a proteasome inhibitor, but not lysosome ones, accelerated the nuclear accumulation of midkine. An expression vector of signal sequence-less midkine, which is produced in the cytosol, was constructed because endocytosed midkine may be translocated to the cytosol from cellular compartments before entering the nucleus. The cytosol-produced midkine underwent proteasomal degradation and accumulated in the nucleus as did the endocytosed midkine. It was polyubiquitinated, and its nuclear accumulation was enhanced by a proteasome inhibitor. We further dissected the midkine molecule to investigate roles in degradation and trafficking. The N-terminal half-domain of midkine was significantly more susceptible to proteasomal degradation, whereas the C-terminal half-domain was sufficient for nuclear localization. Together, these data highlight the desensitization of nuclear targeting by growth factors and indicate a critical role of the proteasome system in it.
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Yukihito Higashi, Masashi Kimura, Keiko Hara, Kensuke Noma, Daisuke Jitsuiki, Keigo Nakagawa, Tetsuya Oshima, Kazuaki Chayama, Taijiro Sueda, Chikara Goto, Hiroaki Matsubara, Toyoaki Murohara, Masao Yoshizumi (2004)  Autologous bone-marrow mononuclear cell implantation improves endothelium-dependent vasodilation in patients with limb ischemia.   Circulation 109: 10. 1215-1218 Mar  
Abstract: BACKGROUND: Patients with limb ischemia were associated with endothelial dysfunction. The purpose of this study was to determine whether autologous bone-marrow mononuclear cell (BM-MNC) implantation improves endothelial dysfunction in patients with limb ischemia. METHODS AND RESULTS: We evaluated the leg blood flow (LBF) response to acetylcholine (ACh), an endothelium-dependent vasodilator, and sodium nitroprusside (SNP), an endothelium-independent vasodilator, before and after BM-MNC implantation in 7 patients with limb ischemia. LBF was measured with a mercury-filled Silastic strain-gauge plethysmograph. The number of BM-MNCs implanted into ischemic limbs was 1.6x10(9)+/-0.3x10(9). The number of CD34+ cells included in the implanted BM-MNCs was 3.8x10(7)+/-1.6x10(7). BM-MNC implantation improved the ankle-brachial pressure index (0.33+/-0.21 to 0.39+/-0.17, P=0.06), transcutaneous oxygen pressure (28.4+/-11.5 to 36.6+/-5.2 mm Hg, P=0.03), and pain-free walking time (0.8+/-0.6 to 2.9+/-2.2 minutes, P=0.02). After BM-MNC implantation, LBF response to ACh was enhanced (19.3+/-6.8 versus 29.6+/-7.1 mL/min per 100 mL; P=0.002). The vasodilatory effect of SNP was similar before and after BM-MNC implantation. CONCLUSIONS: These findings suggest that BM-MNC implantation augments endothelium-dependent vasodilation in patients with limb ischemia.
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Kengo Maeda, Hideki Murakami, Reiko Yoshida, Masatoshi Ichihara, Akihiro Abe, Makoto Hirai, Toyoaki Murohara, Masahide Takahashi (2004)  Biochemical and biological responses induced by coupling of Gab1 to phosphatidylinositol 3-kinase in RET-expressing cells.   Biochem Biophys Res Commun 323: 1. 345-354 Oct  
Abstract: Grb2-associated binder-1 (Gab1) is a docking protein closely related to insulin receptor substrates. We previously reported that tyrosine 1062 in RET receptor tyrosine kinase activated by glial cell line-derived neurotrophic factor (GDNF) represents a binding site for the Shc-Grb2-Gab1 complex, and that the p85 subunit of phosphatidylinositol 3-kinase (PI3K) and SHP2 tyrosine phosphatase is associated with Gab1 in GDNF-treated cells. In the present study, we further analyzed the physiological roles of Gab1 downstream of RET, using Gab1 mutants that lack the binding sites for PI3K (Gab1 PI3K-m) or SHP-2 (Gab1 SHP2-m). Expression of Gab1 PI3K-m in SK-N-MC human primitive neuroectodermal tumor cells expressing wild-type RET markedly impaired Akt phosphorylation, Rac1 activation, and lamellipodia formation that were induced by GDNF whereas expression of Gab1 SHP2-m partially impaired Erk activation. Furthermore, expression of Gab1 PI3K-m, but not Gab1 SHP2-m, in TT human medullary thyroid carcinoma cells expressing RET with a multiple endocrine neoplasia 2A mutation enhanced cytochrome c release, and apoptosis induced by etoposide, suggesting that PI3K is involved in survival of TT cells via a mitochondrial pathway. These findings demonstrated that coupling of Gab1 to PI3K is important for biological responses in RET-expressing cells.
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Mika Aoki, Mikitomo Yasutake, Toyoaki Murohara (2004)  Derivation of functional endothelial progenitor cells from human umbilical cord blood mononuclear cells isolated by a novel cell filtration device.   Stem Cells 22: 6. 994-1002  
Abstract: Endothelial progenitor cells (EPCs) can differentiate from mononuclear cells (MNCs) of adult human peripheral blood, bone marrow, and cord blood during culture. Although MNCs are usually isolated by a Ficoll gradient centrifuge method, this method is time-consuming, and blood is easily contaminated. We developed a novel cell filtration device (StemQuickE, Asahi Kasei Medical, Oita, Tokyo, Japan) to isolate MNCs from human cord blood and examined whether functional EPCs could differentiate from MNCs isolated by this device. Recovery rates of MNCs, CD34(+) and CD133(+) progenitor cells, were significantly greater in the StemQuickE method than in the Ficoll method. During MNC culture, spindle-shaped attaching cells developed, and most of these cells incorporated DiI-acetylated low-density lipoprotein and showed positive binding to fluorescein isothiocyanate-lectin. Reverse transcription-polymerase chain reaction analysis revealed that attaching cells expressed various progenitor and endothelial lineage markers such as KDR, CD31, endothelial cell nitric oxide synthase, CD133, and LOX-1. Culture-expanded EPCs were isolated and labeled with a green fluorescent dye, PKH2-GL, and cocultured with human umbilical vein endothelial cells (HUVECs). EPCs formed angiogenesis-like networks together with HUVECs in 3D matrix gel. Finally, EPCs (3 x 10(5)) were implanted into ischemic hindlimb of nude rats (n = 3), and laser Doppler blood flowmetry (LDBF) revealed that the ratio of ischemic to normal limb LDBF was significantly greater in EPC-transplanted animals compared with controls receiving saline. In conclusion, the novel cell filtration device, StemQuickE, is a useful tool to isolate MNCs from human cord blood. Moreover, MNCs obtained by this filter system can give rise to functional EPCs.
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Takao Nishizawa, Mitsunori Iwase, Hiroaki Kanazawa, Sahoko Ichihara, Gaku Ichihara, Kohzo Nagata, Koji Obata, Kiyoyuki Kitaichi, Toyoharu Yokoi, Masato Watanabe, Takashi Tsunematsu, Yoshihiro Ishikawa, Toyoaki Murohara, Mitsuhiro Yokota (2004)  Serial alterations of beta-adrenergic signaling in dilated cardiomyopathic hamsters: possible role of myocardial oxidative stress.   Circ J 68: 11. 1051-1060 Nov  
Abstract: BACKGROUND: The relationship between enhanced myocardial oxidative stress and impaired beta-adrenergic signaling remains to be characterized during the development of dilated cardiomyopathy. METHODS AND RESULTS: Alterations in myocardial oxidative stress and beta-adrenergic signaling, as well as left ventricular (LV) functional and structural changes, were evaluated during the development of cardiomyopathy in TO-2 hamsters; F1B hamsters served as controls. LV dysfunction was first apparent at 8 weeks of age and deteriorated thereafter in the TO-2 hamsters. At 32 weeks, the animals exhibited heart failure with an increased plasma norepinephrine concentration. Cardiac myolysis, as demonstrated by elevated plasma concentration of cardiac troponin T, peaked at 8 weeks. The glutathione redox ratio revealed increased oxidative stress in the LV myocardium in TO-2 hamsters even at 4 weeks and became manifest after 8 weeks. The hearts of TO-2 hamsters had significantly reduced superoxide dismutase activity from 8 weeks onward compared with control hamsters. However, glutathione peroxidase activity was unchanged at any time point. The LV functional response to isoproterenol was markedly reduced at 8 weeks, without any apparent changes in the amount of beta-adrenergic signaling molecules, and it deteriorated thereafter. Adenylyl cyclase activity was significantly decreased, despite increased amounts of both G(s) alpha mRNA and protein, in the LV myocardium at 18 weeks. CONCLUSIONS: Myocardial oxidative stress is actually enhanced in the initial development of LV dysfunction. Both activation of myocardial oxidative stress and impairment of beta-adrenergic signaling become prominent at the stage of severe LV dysfunction. Myocardial oxidative stress may be involved in the development of beta-adrenergic desensitization.
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Tomofumi Mizuno, Hideo Matsui, Akiko Imamura, Yasushi Numaguchi, Kazuyoshi Sakai, Toyoaki Murohara, Kenji Okumura (2004)  Insulin resistance increases circulating malondialdehyde-modified LDL and impairs endothelial function in healthy young men.   Int J Cardiol 97: 3. 455-461 Dec  
Abstract: BACKGROUND: Endothelial dysfunction is regarded as an early feature of atherosclerosis. Both LDL oxidation and insulin resistance play important roles in the pathogenesis of atherosclerosis. Recent studies have demonstrated a significant association between oxidized LDL and insulin resistance. METHODS: We investigated relationships between insulin resistance, circulating malondialdehyde-modified (MDA)-LDL, and endothelial function in 36 healthy young men. Insulin sensitivity was estimated according to homeostasis model assessment of insulin resistance (HOMA-IR); we defined subjects with values of at least 2.5 as an insulin resistant (n=12) and those with values below 2.5 as insulin sensitive (n=24). We evaluated endothelial function by flow-mediated vasodilation (FMD) of brachial artery during reactive hyperemia, using high-resolution ultrasound. We also measured serum MDA-LDL by a sandwich enzyme-linked immunosorbent assay. RESULTS: MDA-LDL was significantly higher (146+/-46 vs. 101+/-32 IU/l, P=0.002) and FMD was significantly lower (3.94+/-1.53 vs. 5.59+/-1.62 %, P=0.002) in the insulin-resistant group than in the insulin-sensitive group. The resistant group showed a significant inverse correlation between MDA-LDL and FMD (r=-0.675, P=0.016), while the sensitive group did not (r=0.163, NS). By multivariate regression analysis, MDA-LDL and age were determinants of FMD (R2=0.766) in the insulin-resistant group, while no variable determined FMD in the sensitive group. Nitroglycerin-induced endotheliumindependent dilation was similar in both groups. CONCLUSIONS: These results suggest that the production of circulating MDA-LDL may be accelerated by insulin resistance, thus impairing endothelial function even in healthy young men.
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Tomoko S Kato, Akiko Noda, Hideo Izawa, Akira Yamada, Koji Obata, Kohzo Nagata, Mitsunori Iwase, Toyoaki Murohara, Mitsuhiro Yokota (2004)  Discrimination of nonobstructive hypertrophic cardiomyopathy from hypertensive left ventricular hypertrophy on the basis of strain rate imaging by tissue Doppler ultrasonography.   Circulation 110: 25. 3808-3814 Dec  
Abstract: BACKGROUND: The differentiation of hypertrophic cardiomyopathy (HCM) from hypertensive left ventricular hypertrophy (H-LVH) on the basis of morphological information obtained by conventional echocardiography is occasionally problematic. We investigated whether strain rate (SR) imaging derived from tissue Doppler imaging (TDI) is able to discriminate HCM from H-LVH. METHODS AND RESULTS: Conventional echocardiography and TDI were performed with 34 patients with LVH and 16 reference subjects. Mean values of systolic strain (epsilon(sys)), peak systolic SR, and early diastolic SR obtained from 8 left ventricular (LV) segments were calculated. LV pressures were recorded simultaneously in the patients. Patients were diagnosed with HCM (n=20) or H-LVH (n=14) on the basis of conventional echocardiography and endomyocardial biopsy findings. Multivariate analysis revealed that septum/posterior wall thickness ratio (P=0.00013) and epsilon(sys) (P<0.0001) were each able to discriminate HCM from H-LVH. A epsilon(sys) cutoff value of -10.6% discriminated between HCM and H-LVH with a sensitivity of 85.0%, specificity of 100.0%, and predictive accuracy of 91.2%. The combination of the septum/posterior wall thickness ratio and epsilon(sys) discriminated HCM from H-LVH with a predictive accuracy of 96.1%. The epsilon(sys) parameter was significantly correlated with pulmonary arterial wedge pressure, LV end-diastolic pressure, the peak positive first derivative of LV pressure, and the time constant of LV pressure decay. CONCLUSIONS: SR imaging is able to discriminate HCM from H-LVH, with epsilon(sys) reflecting myocardial contractile and lusitropic properties.
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Takumi Yamada, Yoshimasa Murakami, Masahiro Muto, Taro Okada, Mitsuhiro Okamoto, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Teruo Ito, Takahisa Kondo, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2004)  Simple and accurate catheter mapping technique to predict atrial fibrillation foci in the pulmonary veins or posterior right atrium.   Heart Rhythm 1: 4. 427-434 Oct  
Abstract: OBJECTIVES: The purpose of this study was to investigate the efficacy of a novel catheter mapping technique for predicting atrial fibrillation (AF) foci. BACKGROUND: Most AF originates from pulmonary veins (PVs), but some originate from the right atrium. METHODS: We developed an algorithm by correlating the cardiac recordings obtained from multielectrode catheters placed in the posterior right atrium (RA) and esophagus during pacing from the PVs and superior vena cava (SVC) or crista terminalis (CT) in 10 AF patients. We tested the algorithm's accuracy prospectively in 46 AF patients. RESULTS: During pacing from the left PVs, the esophageal potentials preceded all other potentials. During pacing from both the right PVs and SVC-CT, the first component (FP) of the double potential (DP) recorded in the posterior RA preceded all other potentials. The amplitude of the FP was higher than that of the second DP component during pacing from the SVC-CT, whereas the reverse occurred from the right PVs. The activation sequence of the FPs and esophageal potentials was from superior to inferior during pacing from the superior PVs, whereas the reverse occurred from the inferior PVs. The accuracy of predicting 34 foci in the right PVs, 28 foci in left PVs, and 6 foci in SVC-CT was 100% for all, respectively. The accuracy of discriminating foci in the superior PVs from those in the inferior PVs was 97% in the right PVs and 96% in the left PVs. CONCLUSIONS: The technique using mapping catheters placed in the posterior RA and esophagus is feasible and effective for mapping and ablating AF.
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Akira Kimura, Kenji Okumura, Shinji Mokuno, Yasushi Numaguchi, Hideo Matsui, Toyoaki Murohara (2004)  Higher viscosity participates in the regulation of coronary flow via nitric oxide and indomethacin-sensitive contracting factor.   Can J Physiol Pharmacol 82: 12. 1096-1102 Dec  
Abstract: Few studies have reported on the association of viscosity with coronary circulation. We evaluated the change in coronary flow after dextran was added to a perfusion solution to increase viscosity in isolated rat hearts. We also measured NOx- production induced by the change in shear stress in the coronary effluent, as a marker of NO synthesis. The baseline coronary flow was not influenced by the presence of either the cyclooxygenase inhibitor indomethacin, the thromboxane A2 (TXA2)-prostaglandin H2 (PGH2) receptor antagonist ONO-3708, or the TXA2 synthase inhibitor OKY-046. After exposure to solution containing 0.5% dextran, the coronary flow first decreased and then gradually increased until 10 min. The initial decrease in coronary flow was inhibited by indomethacin, ONO-3708, and OKY-046 individually. The gradual increase was completely inhibited by the NO inhibitor L-NAME, but not by indomethacin or ONO-3708. OKY-046 partially inhibited the increase. NOx- levels in the effluent were higher after the dextran solution was administered, and the increased NOx- levels were inhibited by L-NAME. The increased NOx- levels were not inhibited by inhibitors of the cyclooxygenase pathway. It appears that a higher viscosity of perfusion solution induced a gradual increase in NO production and was associated with increased production of indomethacin-sensitive contracting factor.
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Akiko Imamura, Kenji Okumura, Hideo Matsui, Tomofumi Mizuno, Yasuhiro Ogawa, Hajime Imai, Yasushi Numaguchi, Kazuyoshi Sakai, Toyoaki Murohara (2004)  Endothelial nitric oxide synthase and methylenetetrahydrofolate reductase gene polymorphisms are associated with endothelial dysfunction in young, healthy men.   Can J Cardiol 20: 12. 1229-1234 Oct  
Abstract: BACKGROUND: The guanine to thymine polymorphism at position 894 of the eNOS gene (resulting in a change from glutamate to aspartate [Asp] at codon 298 [Asp298]) and the methylenetetrahydrofolate reductase (MTHFR) gene polymorphism (C677T) have been reported to be associated with atherosclerosis and cardiovascular disease. Endothelial dysfunction is considered to be the earliest stage of atherosclerosis. OBJECTIVES: To examine whether common eNOS and MTHFR gene polymorphisms are associated with endothelial dysfunction in young, healthy men without overt cardiovascular disease. SUBJECTS AND METHODS: Flow-mediated, endothelium-dependent vasodilation (FMD) and glyceryl trinitrate-induced, endothelium-independent vasodilation (GTN) were measured using high-resolution ultrasound of the brachial artery in 53 young, healthy men assigned to eNOS and MTHFR genotypes. RESULTS: Subjects with the eNOS Asp298 allele (n=15) showed significantly reduced FMD:GTN compared with those without this allele (n=38) (0.23+/-0.13 [mean +/- SD] versus 0.35+/-0.14, P=0.0072), whereas there was no significant difference in GTN between these two groups. Although subjects with the MTHFR T677 allele did not show significantly reduced levels of FMD:GTN, subjects with the eNOS Asp298 allele and who were carriers of the MTHFR T677 allele demonstrated markedly reduced levels of FMD:GTN compared with noncarriers (0.14+/-0.05 versus 0.28+/-0.13, P=0.04). CONCLUSIONS: The data suggest that even in young men, the eNOS Asp298 allele may be involved in endothelial dysfunction before any overt vascular disease has occurred. Furthermore, a combination of the eNOS Asp298 and MTHFR T677 alleles may exaggerate endothelial dysfunction and may contribute to a comparatively earlier development of atherosclerosis.
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Takahisa Kondo, Koichi Kobayashi, Toyoaki Murohara (2004)  Nitric oxide signaling during myocardial angiogenesis.   Mol Cell Biochem 264: 1-2. 25-34 Sep  
Abstract: Ischemic heart disease develops as a consequence of coronary atherosclerotic lesion formation. Coronary collateral vessels and microvascular angiogenesis develop as an adaptive response to myocardial ischemia, which ameliorates the function of the damaged heart. Angiogenesis, the formation of new blood vessels from pre-existing vascular bed, is of paramount importance in the maintenance of vascular integrity both in the repair process of damaged tissue and in the formation of collateral vessels in response to tissue ischemia. Angiogenesis is modulated by a multitude of cytokines/chemokines and growth factors. In this regard, angiogenesis cannot be viewed as a single process. It is likely that different mediators are involved in different phases of angiogenesis. Vascular endothelial cells (ECs) produce nitric oxide (NO), an endothelium-derived labile molecule, which maintains vascular homeostasis and thereby prevents vascular atherosclerotic changes. In patients with ischemic heart disease, the release of endothelium-derived NO is decreased, which plays an important role in the atherosclerotic disease progression. In recent years, endothelium-derived NO has been shown to modulate angiogenesis in vitro and in vivo. In this review, we summarize recent progress in the field of the NO-mediated regulation of postnatal angiogenesis, particularly in response to myocardial ischemia.
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Yoko Kitamura, Kenji Okumura, Akiko Imamura, Tomofumi Mizuno, Michitaka Tsuzuki, Yasushi Numaguchi, Hideo Matsui, Toyoaki Murohara (2004)  Association of plasminogen activator inhibitor-1 4G/5G gene polymorphism with variations in the LDL particle size in healthy Japanese men.   Clin Chim Acta 347: 1-2. 209-216 Sep  
Abstract: BACKGROUND: Several studies have supported the association between a predominance of small, dense low-density lipoprotein (LDL) and the risk of coronary artery disease. As another potentially atherogenic factor, impaired fibrinolytic activity due to increased plasminogen activator inhibitor-1 (PAI-1) concentrations has been shown. In addition, the 4G allele of the 4G/5G polymorphism in the promoter region of the PAI-1 gene is reported to be associated with the atherogenic lipid profile. We investigated the relation between the PAI-1 gene polymorphism and LDL particle size. METHODS: A total of 156 healthy Japanese male subjects were recruited. The diameter of LDL particles was determined at their peak size using polyacrylamide gels using fresh plasma samples. RESULTS: Fasting insulin and triglyceride concentrations were found to be significantly higher, and the LDL particle size was smaller in the homozygotes for the 5G allele than in the carriers of the 4G allele. An analysis of covariance (ANCOVA) adjusting for insulin and triglyceride concentrations showed a consistently significant difference in LDL particle size between the two groups. In the forward stepwise multiple regression analysis, triglycerides, insulin, and the PAI-1 5G/5G genotype remained in the model as independent and significant predictors capable of influencing the LDL particle size. CONCLUSIONS: Our findings suggest that the 4G/5G polymorphism of the PAI-1 gene might be associated with LDL particle size in healthy Japanese males.
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Toshifumi Shimada, Yoshiaki Takeshita, Toyoaki Murohara, Ken-ichiro Sasaki, Kimiyasu Egami, Satoshi Shintani, Yosuke Katsuda, Hisao Ikeda, Yo-ichi Nabeshima, Tsutomu Imaizumi (2004)  Angiogenesis and vasculogenesis are impaired in the precocious-aging klotho mouse.   Circulation 110: 9. 1148-1155 Aug  
Abstract: BACKGROUND: The effects of aging on angiogenesis (vascular sprouting) and vasculogenesis (endothelial precursor cell [EPC] incorporation into vessels) are not well known. We examined whether ischemia-induced angiogenesis/vasculogenesis is altered in klotho (kl) mutant mice, an animal model of typical aging. METHODS AND RESULTS: After unilateral hindlimb ischemia, laser Doppler blood-flow (LDBF) analysis revealed a decreased ischemic-normal LDBF ratio in kl mice. Tissue capillary density was also suppressed in kl mice (+/+>+/kl>kl/kl). Aortic-ring culture assay showed impaired angiogenesis in kl/kl mice, accompanied by reduced endothelium-derived nitric oxide release. Moreover, the rate of transplanted homologous bone marrow cells incorporated into capillaries in ischemic tissues (vasculogenesis) was lower in kl/kl mice than in wild-type (+/+) mice, which was associated with a decrease in the number of c-Kit+CD31+ EPC-like mononuclear cells in bone marrow and in peripheral blood. Finally, the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor cerivastatin restored the impaired neovascularization in kl/kl mice, accompanied by an increase in c-Kit+CD31+ cells in bone marrow and peripheral blood, and enhanced angiogenesis in the aortic-ring culture. CONCLUSIONS: Angiogenesis and vasculogenesis are impaired in kl mutant mice, a model of typical aging. Moreover, the age-associated impairment of neovascularization might be a new target of statin therapy.
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Koji Yamamoto, Takahisa Kondo, Satoshi Suzuki, Hideo Izawa, Masayoshi Kobayashi, Nobuhiko Emi, Kimihiro Komori, Tomoki Naoe, Junki Takamatsu, Toyoaki Murohara (2004)  Molecular evaluation of endothelial progenitor cells in patients with ischemic limbs: therapeutic effect by stem cell transplantation.   Arterioscler Thromb Vasc Biol 24: 12. e192-e196 Dec  
Abstract: OBJECTIVE: Although some patients with limb ischemia have recently undergone therapeutic angiogenesis by cell transplantation, their angiogenic potential has not been well characterized. It is also important to evaluate endothelial progenitor cell (EPC) contents in different stem cell sources to choose the best material for therapeutic angiogenesis. METHODS AND RESULTS: We quantitated the mRNA expression of EPC-specific molecules (eg, Flk-1, Flt-1, CD133, VE-cadherin, etc) in bone marrow-derived or peripheral blood-derived mononuclear cells obtained from patients with ischemic limbs, using real-time reverse-transcription polymerase chain reaction technique. The mRNA expression level of EPC markers was significantly lower in the patients than in healthy controls, which was consistent with results of flow cytometric analysis. However, the implantation of autologous bone marrow mononuclear cells increased the circulating EPCs in the peripheral blood of patients. We furthermore revealed the different expression pattern of EPC markers in possible sources for stem cell transplantation, including normal bone marrow, peripheral blood obtained from recombinant granulocyte colony-stimulating factor-treated donor, and umbilical cord blood. CONCLUSIONS: Patients with peripheral obstructive arterial diseases may have lower angiogenic potential because of decreased expression of EPC specific molecules in their marrow and blood. Therapeutic angiogenesis by transplantation of autologous marrow mononuclear cells increased circulating EPCs in the patients and improved ischemic symptoms.
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Jin-Ho Choi, Jin Hur, Chang-Hwan Yoon, Ji-Hyun Kim, Choon-Soo Lee, Seock-Won Youn, Il-Young Oh, Carsten Skurk, Toyoaki Murohara, Young-Bae Park, Kenneth Walsh, Hyo-Soo Kim (2004)  Augmentation of therapeutic angiogenesis using genetically modified human endothelial progenitor cells with altered glycogen synthase kinase-3beta activity.   J Biol Chem 279: 47. 49430-49438 Nov  
Abstract: Previously we reported that inhibition of glycogen synthase kinase-3beta (GSK3beta), a key regulator in many intracellular signaling pathways, enhances the survival and migration of vascular endothelial cells. Here we investigated the effect of inhibition of GSK3beta activity on the angiogenic function of endothelial progenitor cell (EPC) and demonstrated a new therapeutic angiogenesis strategy using genetically modified EPC. As we previously reported, two biologically distinct types of EPC, spindle-shaped "early EPC" and cobblestone-shaped "late EPC" could be cultivated from human peripheral blood. Catalytically inactive GSK3beta gene was transduced into both EPC. Inhibition of GSK3beta signaling pathway led to increased nuclear translocation of beta-catenin and increased secretion of angiogenic cytokines (vascular endothelial growth factor and interleukin-8). It enhanced the survival and proliferation of early EPC, whereas it promoted the survival and differentiation of late EPC. Transplantation of either of these genetically modified EPC into the ischemic hind limb model of athymic nude mouse significantly improved blood flow, limb salvage, and tissue capillary density compared with nontransduced EPC. Inhibition of GSK3beta signaling of either of these genetically modified EPC augmented the in vitro and in vivo angiogenic potency of these cell populations. These data provide evidence that GSK3beta has a key role in the angiogenic properties of EPC. Furthermore, the genetic modification of EPC to alter this signaling step can improve the efficacy of cell-based therapeutic vasculogenesis.
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Takumi Yamada, Yoshimasa Murakami, Masahiro Muto, Taro Okada, Mitsuhiro Okamoto, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Teruo Ito, Takahisa Kondo, Yasuya Inden, Makoto Hirai, Toyoaki Murohara (2004)  Electrophysiologic characteristics of atrial tachycardia originating from the right pulmonary veins or posterior right atrium: double potentials obtained from the posterior wall of the right atrium can be useful to predict foci of atrial tachycardia in right pulmonary veins or posterior right atrium.   J Cardiovasc Electrophysiol 15: 7. 745-751 Jul  
Abstract: INTRODUCTION: The right pulmonary veins (RPVs) and posterior wall of the right atrium (PRA) are anatomically located adjacent to each other. The aim of this study was to demonstrate the electrophysiologic characteristics of atrial tachycardia (AT) originating from the PRA or RPVs. METHODS AND RESULTS: A total of 26 consecutive patients with AT originating from the RPVs or PRA underwent detailed atrial endocardial mapping and successful radiofrequency catheter ablation. Eight foci were found in the PRA and 18 foci in the RPVs. Analysis of P wave configuration showed that lead V1 was the most helpful in distinguishing the AT foci between these two sites. In all cases, double potential (DP) configurations were recorded from several electrodes of a multielectrode catheter placed in the PRA, and the first DP component (FP) was the earliest potential recorded from the right atrium during the tachycardia. The amplitude of the FP was higher than that of the second DP component (SP) for AT foci originating in the PRA, whereas the reverse occurred for those in the RPV. The activation sequence of the FP was from superior to inferior for the AT foci in the superior RPV, whereas the reverse occurred for the AT foci in the inferior RPV. CONCLUSION: P wave configuration in lead V1 is helpful in distinguishing AT foci between those originating in the PRA and RPVs. The DPs obtained from the PRA can be useful in predicting whether AT foci originate from the PRA or RPVs.
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Yasuo Takada, Satoshi Isobe, Mitsuhiro Okada, Akitada Ando, Makoto Nonokawa, Yasuya Inden, Yasushi Tomita, Akio Suzuki, Makoto Hirai, Toyoaki Murohara (2004)  Effects of antiarrhythmic agents on left ventricular function during exercise in patients with chronic left ventricular dysfunction.   Ann Nucl Med 18: 3. 209-219 May  
Abstract: This study was designed to determine the effects of antiarrhythmic agents on global left ventricular (LV) function during exercise in patients with chronic LV dysfunction. Thirty-five patients with LV dysfunction [LV ejection fraction (LVEF) < 45%] and ventricular arrhythmias were studied. They were randomly classified into 3 groups: patients who received a single oral dose of 6 mg/kg disopyramide phosphate (n = 12), those who received a single oral dose of 4 mg/kg mexiletine hydrochloride (n = 12), and those who received a single oral dose of 4 mg/kg pilsicainide hydrochloride (n = 11). First, all patients were subjected to baseline rest and peak exercise, equilibrium-gated cardiac-pool scintigraphy with 99mTc-human serous albumin of 740 MBq (baseline data). Second, on a separate day, they were given drugs once, and were subsequently subjected to rest and peak exercise equilibrium-gated cardiac-pool scintigraphy. Exercise LVEF and peak ejection rate (PER) after administration were significantly lower in the disopyramide and pilsicainide groups than in the mexiletine group (p < 0.05, respectively). The changes in LVEF and PER from rest to peak exercise after administration were significantly less than the baseline changes in those in the disopyramide and pilsicainide groups (p < 0.05, respectively). However, no significant changes in functional parameters were recognized in the mexiletine group. Due care should be taken when disopyramide and pilsicainide are administered to patients with chronic LV dysfunction since they reduce systolic LV function during exercise.
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Hiroshi Niiyama, Hisashi Kai, Tomoka Yamamoto, Toshifumi Shimada, Ken-Ichiro Sasaki, Toyoaki Murohara, Kensuke Egashira, Tsutomu Imaizumi (2004)  Roles of endogenous monocyte chemoattractant protein-1 in ischemia-induced neovascularization.   J Am Coll Cardiol 44: 3. 661-666 Aug  
Abstract: OBJECTIVES: We sought to investigate the role of endogenous monocyte chemoattractant protein (MCP)-1 in ischemia-induced neovascularization. BACKGROUND: Roles of inflammatory changes including macrophage infiltration are suggested in ischemic neovascularization. METHODS: Unilateral hindlimb ischemia was induced by excising surgically the entire femoral artery and vein in mice. Immediately after operation, plasmid deoxyribonucleic acid encoding a dominant negative mutant of MCP-1 (7ND) or the empty plasmid (mock) was injected into the ipsilateral thigh adductor muscle. RESULTS: In mock-treated mice, MCP-1 was upregulated transiently in ischemic hindlimb peaking at day 3. Serial laser Doppler blood flow (LDBF) analysis showed an abrupt decrease in blood flow, followed by a recovery to the near-normal levels in mock-treated mice; 7ND treatment had no effects on the initial decrease in LDBF but deteriorated the recovery. At day 3, macrophage infiltration and inductions of tumor necrosis factor (TNF)-alpha and vascular endothelial growth factor (VEGF) were prominent in the ischemic adductor muscle in mock-treated mice; 7ND treatment significantly reduced macrophage infiltration and suppressed TNF-alpha and VEGF inductions in response to ischemia. At day 21, postmortem angiography and anti-CD31 immunohistostaining revealed well-developed collateral vessels and capillary formation, respectively, in the ischemic muscle of mock-treated mice; 7ND overexpression remarkably suppressed the collateral vessel formation and capillary formation. CONCLUSIONS: Endogenous MCP-1 may play a role in ischemia-induced neovascularization by recruiting macrophages that activate TNF-alpha and VEGF inductions.
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Hideo Izawa, Mitsunori Iwase, Yasushi Takeichi, Fuji Somura, Kohzo Nagata, Takao Nishizawa, Akiko Noda, Toyoaki Murohara, Mitsuhiro Yokota (2003)  Effect of nicorandil on left ventricular end-diastolic pressure during exercise in patients with hypertrophic cardiomyopathy.   Eur Heart J 24: 14. 1340-1348 Jul  
Abstract: AIMS: Impaired coronary microcirculation is thought to contribute to myocardial ischaemia, causing an abnormal increase in left ventricular end-diastolic pressure during exercise in individuals with hypertrophic cardiomyopathy. The effects of nicorandil on left ventricular end-diastolic pressure during exercise were examined in patients with this condition. METHODS AND RESULTS: Left ventricular pressures and dimensions were measured simultaneously during supine bicycle exercise in 23 patients with nonobstructive hypertrophic cardiomyopathy, before and after intravenous injection of either nicorandil (0.1 mg/kg) or propranolol (0.15 mg/kg). Exercise thallium-201 scintigraphy was also performed. Patients were grouped according to the changes in left ventricular end-diastolic pressure during exercise before treatment. Group I comprised 13 patients in whom left ventricular end-diastolic pressure increased progressively to abnormal values during exercise; group II comprised 10 patients in whom left ventricular end-diastolic pressure changed biphasically. The extents of both left ventricular hypertrophy and ischemic burden during exercise were greater in group I than in group II. Of the eight group I patients who received nicorandil, four individuals exhibited biphasic changes in left ventricular end-diastolic pressure during exercise after its administration whereas four subjects showed no such effect of the drug. Left ventricular end-diastolic pressure increased progressively during exercise after propranolol treatment in all 6 group II patients given this drug. CONCLUSION: Nicorandil has a salutary effect on the changes in left ventricular end-diastolic pressure during exercise in patients with hypertrophic cardiomyopathy.
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Ken-ichiro Sasaki, Junli Duan, Toyoaki Murohara, Hisao Ikeda, Satoshi Shintani, Toshifumi Shimada, Takako Akita, Kimiyasu Egami, Tsutomu Imaizumi (2003)  Rescue of hypercholesterolemia-related impairment of angiogenesis by oral folate supplementation.   J Am Coll Cardiol 42: 2. 364-372 Jul  
Abstract: OBJECTIVES: We examined whether oral folate supplementation would rescue a hypercholesterolemia (HC)-related impairment of ischemia-induced angiogenesis. BACKGROUND: Folate protects against endothelial dysfunction, but the effect of folate supplementation on angiogenesis is little known. METHODS: Sprague-Dawley rats were divided into four groups. Control rats were fed a normal diet (n = 18); HC rats (n = 18) were fed 2% cholesterol diet; and HC + folate (HC+F) rats were fed an HC diet with oral folate (0.003% in water). The left femoral artery and vein were surgically excised, and angiogenesis in the ischemic limb was evaluated. We also examined the effects of Nomega-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthase, on angiogenesis in the HC+F state. RESULTS: Laser Doppler blood flow (LDBF) analysis showed lower ischemic/normal LDBF ratio in the HC group than in the control group. Angiographic and histologic analyses on day 14 revealed a smaller angiographic score (p < 0.001) and capillary density (p < 0.001) in the HC group than in controls, which were associated with reduced tissue NOx and cyclic guanosine monophosphate (cGMP) levels. The LDBF ratio, angiographic score, and capillary density were significantly restored in the HC+F group (p < 0.01 vs. HC), which were associated with increased serum folate and tissue NOx and cGMP levels. Finally, L-NAME treatment abolished the beneficial action of folate on angiogenesis in the HC state. CONCLUSIONS: Ischemia-induced angiogenesis was inhibited by HC, which was rescued by oral folate supplementation, at least in part, via an NO-dependent manner.
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Kimiyasu Egami, Toyoaki Murohara, Toshifumi Shimada, Ken-Ichiro Sasaki, Satoshi Shintani, Takeshi Sugaya, Masahiro Ishii, Teiji Akagi, Hisao Ikeda, Toyojiro Matsuishi, Tsutomu Imaizumi (2003)  Role of host angiotensin II type 1 receptor in tumor angiogenesis and growth.   J Clin Invest 112: 1. 67-75 Jul  
Abstract: Although the renin angiotensin system (RAS) is a major regulator of vascular homeostasis, the role of the RAS in tumor angiogenesis is little understood. Here we show that host angiotensin II (ATII) type 1 (AT1) receptor plays an important role in angiogenesis and growth of tumor cells engrafted in mice. Subcutaneous B16-F1 melanoma-induced angiogenesis as assessed by tissue capillary density and microangiography was prominent in WT mice but was reduced in AT1a receptor-deficient (AT1a-/-) mice. Consequently, tumor growth rate was significantly slower, and the mouse survival rate was greater, in AT1a-/- mice than in WT mice. Tumor growth was also reduced in WT mice treated with TCV-116, a selective blocker of AT1 receptor. Because the beta-galactosidase gene was inserted into the AT1a gene locus in AT1a-/- mice, the site of beta-galactosidase expression represents the AT1a receptor expression in these mutant mice. In tumor-implanted AT1a-/- mice, the major site of the beta-galactosidase expression was macrophages in tissues surrounding tumors. Moreover, the number of infiltrated macrophages was significantly lower in AT1a-/- mice than in WT mice, and double-immunofluorescence staining revealed that these macrophages expressed VEGF protein intensively. Therefore, the host ATII-AT1 receptor pathway supports tumor-associated macrophage infiltration, which results in enhanced tissue VEGF protein levels. The host ATII-AT1 receptor pathway thereby plays important roles in tumor-related angiogenesis and growth in vivo.
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Takako Akita, Toyoaki Murohara, Hisao Ikeda, Ken-Ichiro Sasaki, Toshifumi Shimada, Kimiyasu Egami, Tsutomu Imaizumi (2003)  Hypoxic preconditioning augments efficacy of human endothelial progenitor cells for therapeutic neovascularization.   Lab Invest 83: 1. 65-73 Jan  
Abstract: A subset of human peripheral blood mononuclear cells (PB-MNCs) differentiate into endothelial progenitor cells (EPCs) that participate in postnatal neovascularization. Although tissue ischemia can mobilize EPCs from bone marrow, the effects of hypoxia on differentiation and angiogenic function of EPCs are little known. We examined whether hypoxic conditioning would modulate differentiation and function of human PB-MNC-derived EPCs. A subset of PB-MNCs gave rise to EPC-like attaching (AT) cells under either normoxic or hypoxic conditions. However, hypoxia much enhanced the differentiation of AT cells from PB-MNCs compared with normoxia. AT cells released vascular endothelial growth factor (VEGF) protein and expressed CD31 and kinase insert domain receptor/VEGFR-2, endothelial lineage markers, on their surface, which were also enhanced by hypoxia. Both a neutralizing anti-VEGF mAb and a KDR-specific receptor tyrosine kinase inhibitor, SU1498, suppressed PB-MNC differentiation into EPC-like AT cells in a dose-dependent manner. Migration of AT cells in response to VEGF as examined by a modified Boyden chamber apparatus was also enhanced by hypoxia. Finally, in vivo neovascularization efficacy was significantly enhanced by in vitro hypoxic conditioning of AT cells when cells were transplanted into the ischemic hindlimb of immunodeficient nude rats. In conclusion, hypoxia directly stimulated differentiation of EPC-like AT cells from human PB-MNC culture. Moreover, hypoxic preconditioning of AT cells before in vivo transplantation is a useful means to enhance therapeutic vasculogenesis.
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W Himeno, T Akagi, J Furui, Y Maeno, M Ishii, K Kosai, T Murohara, H Kato (2003)  Increased angiogenic growth factor in cyanotic congenital heart disease.   Pediatr Cardiol 24: 2. 127-132 Mar/Apr  
Abstract: To examine the relationship between the plasma levels of angiogenic growth factors and the severity of cyanosis, 80 patients with cyanotic heart disease (CHD) and 81 healthy controls were studied. Median age and mean arterial blood oxygen saturation respectively were 4.2 years and 81% in CHD subjects and 4.8 years and 98% in controls. Vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) were measured in plasma using enzyme-linked immunoassay. Plasma VEGF levels in controls depended negatively on age (p < 0.0001) until 3 months, when VEGF was no longer elevated. No such age dependence was found for HGF. Although VEGF levels did not differ between CHD and control subjects up to the age of 3 months, VEGF was significantly elevated in CHD patients older than 3 months compared to controls of similar age (149 +/- 106 vs 65 +/- 23 pg/ml, p < 0.0001). Moreover, the VEGF levels were negatively correlated with oxygen saturation (p = 0.03) and positively correlated with hemoglobin (p = 0.004) in CHD patients aged between 3 months and 10 years. Although the physiologic elevation of VEGF in the neonatal period decreases rapidly if oxygen saturation is normal, VEGF elevations persist if systemic hypoxia is present.
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Ryuichiro Murakami, Fukushi Kambe, Hirohito Mitsuyama, Kenji Okumura, Toyoaki Murohara, Satoru Niwata, Ryohei Yamamoto, Hisao Seo (2003)  Cyclosporin A enhances interleukin-8 expression by inducing activator protein-1 in human aortic smooth muscle cells.   Arterioscler Thromb Vasc Biol 23: 11. 2034-2040 Nov  
Abstract: OBJECTIVE: Cyclosporin A (CsA) and tacrolimus (FK506) are widely used as immunosuppressants. However, their use has been hampered by various adverse effects, such as acceleration of atherosclerosis. Interleukin (IL)-8, a chemotactic cytokine, plays an important role in pathogenesis of atherosclerosis. We thus investigated whether synthesis of IL-8 from primary human aortic smooth muscle cells is influenced by CsA and FK506. METHODS AND RESULTS: Northern blot analysis revealed that CsA increased IL-8 mRNA level and enhanced its increase by epidermal growth factor or tumor necrosis factor-alpha. In contrast, FK506 had no effect on the mRNA level. IL-8 accumulation in culture media was also increased by CsA. Stability of IL-8 mRNA was not affected by CsA, whereas luciferase reporter gene assay using the human IL-8 promoter revealed that CsA significantly augmented the promoter activity. Electrophoretic mobility shift assay showed that binding activity of activator protein (AP)-1 was increased by CsA, and introduction of a mutation into the AP-1 site in the promoter abolished its CsA-dependent activation. The increased AP-1 binding activity was accompanied by c-Fos synthesis. CONCLUSIONS: CsA stimulates synthesis of IL-8 via activation of AP-1 in human aortic smooth muscle cells, providing a novel aspect of biological effects of CsA on the cells.
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Ryotaro Takahashi, Kenji Okumura, Hideo Matsui, Yoshihiro Saburi, Hiroki Kamiya, Kenichiro Matsubara, Toru Asai, Masafumi Ito, Toyoaki Murohara (2003)  Impact of alpha-tocopherol on cardiac hypertrophy due to energy metabolism disorder: the involvement of 1,2-diacylglycerol.   Cardiovasc Res 58: 3. 565-574 Jun  
Abstract: OBJECTIVE: The juvenile visceral steatosis (JVS) mouse, a murine model of systemic carnitine deficiency, shows a disorder of fatty acid oxidation and develops cardiac hypertrophy associated with lipid accumulation. Recently, alpha-tocopherol was shown to decrease 1,2-diacylglycerol (DAG) levels. We investigated the involvement of DAG in cardiac hypertrophy due to energy metabolism disorder by evaluating the effects of alpha-tocopherol administration on the hearts of JVS mice. METHODS: Both JVS and control mice were fed a high alpha-tocopherol diet or a standard diet from 4 to 8 weeks of age. Myocardial DAG levels and fatty acid composition were assessed at 8 weeks of age. RESULTS: The ventricular to body weight ratio in the JVS mice was significantly higher than that in the control mice [11.2+/-0.1 (mean+/-S.E.M.) versus 3.8+/-0.1 mg/g, P<0.01], and was reduced by alpha-tocopherol treatment (9.7+/-0.2 mg/g, P<0.01 versus JVS mice). However, echocardiographic analysis showed the exaggeration of left ventricular dilatation in the alpha-tocopherol treated JVS mice (P<0.01 versus JVS mice). The myocardial thiobarbituric-acid-reactive substance level was not affected by alpha-tocopherol treatment. The myocardial DAG level was 2.5-fold higher in the JVS mice compared with that in the control mice (2004+/-136 versus 806+/-36 ng/mg dry weight, P<0.01) with a significant increase in 18:1 and 18:2 fatty acids. alpha-Tocopherol treatment reduced myocardial DAG levels in the JVS mice (1443+/-49 ng/mg dry weight, P<0.01 versus JVS mice) without any alteration of the fatty acid composition. CONCLUSIONS: alpha-Tocopherol treatment may partially reduce cardiac hypertrophy but it may also depress cardiac function in the JVS mice by decreasing the myocardial DAG level. An increase in DAG might be involved in the development of cardiac hypertrophy and in the maintenance of cardiac function in energy metabolism disorder of the heart.
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Toyoaki Murohara (2003)  Angiogenesis and vasculogenesis for therapeutic neovascularization.   Nagoya J Med Sci 66: 1-2. 1-7 May  
Abstract: Peripheral blood of adult species contains endothelial progenitor cells (EPCs) that participate in neovascularization, consistent with postnatal vasculogenesis. EPCs can be isolated not only from peripheral blood but also from bone marrow and human umbilical cord blood. In vitro culture-expanded EPCs participate in endothelial network formation (capillary formation) in vitro, and transplanted EPCs have been incorporated into sites of active neovascularization. For example, transplanted human EPCs formed capillaries among preserved skeletal myocytes in the ischemic hindlimb of athymic nude rats in vivo. Furthermore, transplantation of EPCs functionally augmented neovascularization in response to hindlimb ischemia. Thus, transplantation of EPCs may become a useful strategy to modulate postnatal neovascularization.
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Satoshi Isobe, Hideo Izawa, Yasushi Takeichi, Makoto Nonokawa, Mamoru Nanasato, Akitada Ando, Katsuhiko Kato, Mitsuru Ikeda, Toyoaki Murohara, Mitsuhiro Yokota (2003)  Relationship between exercise-induced myocardial ischemia and reduced left ventricular distensibility in patients with nonobstructive hypertrophic cardiomyopathy.   J Nucl Med 44: 11. 1717-1724 Nov  
Abstract: Many studies have demonstrated that reduced left ventricular (LV) diastolic distensibility plays a key role in the pathophysiology of hypertrophic cardiomyopathy (HCM). However, the relationship between myocardial ischemia and reduced LV distensibility in HCM remains unclear. We aimed to clarify the relationship between exercise-induced ischemia and reduced LV distensibility in patients with HCM. METHODS: Twenty patients with HCM and 5 age-matched control subjects underwent stress-redistribution (201)Tl myocardial scintigraphy and biventricular cardiac catheterization and echocardiography at rest and during exercise. Scintigraphic defect analysis was interpreted using Berman's 20-segment model. The summed stress score (SSS) was calculated as the sum of scores of the 20 LV segments and the summed difference score (SDS) was calculated as the sum of differences between each of the 20 LV segments on stress and rest images. RESULTS: Patients were divided into 2 groups according to the (201)Tl defect as follows: 9 patients with an SSS on (201)Tl of >or=10 and an SDS on (201)Tl of >or=5 (ischemic group) and 11 patients with an SSS of <10 or an SDS of <5 (nonischemic group). The absolute increases from rest to peak exercise in LV end-diastolic pressure (LVEDP) and pulmonary artery wedge pressure were significantly greater (15.5 +/- 5.2 vs. 7.6 +/- 5.5 mm Hg and 17.3 +/- 5.0 vs. 8.9 +/- 5.0 mm Hg, P < 0.01, respectively), and the percentage changes from rest to peak exercise in the maximum first derivative of LV pressure and LV pressure half-time were significantly smaller in the ischemic HCM group compared with the nonischemic HCM group (70% +/- 24% vs. 123% +/- 43% and -32% +/- 6.4% vs. -44% +/- 9.4%, P < 0.01, respectively). However, the end-diastolic dimensions did not differ between the 2 HCM groups. One of the 9 patients in the ischemic group, as revealed by fill-in on (201)Tl scintigraphy, showed increased (18)F-FDG uptake in the anteroseptal wall. CONCLUSION: Some HCM patients show a significant increase in LVEDP without chamber dilatation, indicating reduced LV diastolic distensibility. Myocardial ischemia may at least in part contribute to this condition.
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Kohzo Nagata, Koji Obata, Mari Odashima, Akira Yamada, Fuji Somura, Takao Nishizawa, Sahoko Ichihara, Hideo Izawa, Mitsunori Iwase, Akemi Hayakawa, Toyoaki Murohara, Mitsuhiro Yokota (2003)  Nicorandil inhibits oxidative stress-induced apoptosis in cardiac myocytes through activation of mitochondrial ATP-sensitive potassium channels and a nitrate-like effect.   J Mol Cell Cardiol 35: 12. 1505-1512 Dec  
Abstract: The anti-anginal drug nicorandil has been shown to inhibit apoptosis by activating mitochondrial ATP-sensitive potassium (K(ATP)) channels. The possible contribution of the nitrate moiety of this drug to its anti-apoptotic effect has now been investigated in neonatal rat ventricular myocytes subjected to oxidative stress. Exposure of cultured myocytes to 100 micromol/l hydrogen peroxide (H(2)O(2)) increased the number of nuclei stained by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling technique as well as induced internucleosomal DNA fragmentation, loss of mitochondrial membrane potential, cytochrome c release into the cytosol, and activation of caspases-3 and -9, all of which are characteristics of apoptosis. Pretreatment of cells with nicorandil (100 micromol/l) inhibited these effects of H(2)O(2). Both the mitochondrial K(ATP) channel antagonist 5-hydroxydecanoate (5-HD) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylyl cyclase, attenuated the anti-apoptotic effect of nicorandil in concentration-dependent manners. Coapplication of ODQ (10 micromol/l) and 5-HD (500 micromol/l) completely abolished nicorandil-induced cytoprotection. The effect of nicorandil was also reduced by an inhibitor of cGMP-dependent protein kinase (KT5823, 1 micromol/l). The nitric oxide donor (+/-)-S-nitroso-N-acetylpenicillamine (SNAP, 50 micromol/l) mimicked the protective effect of nicorandil in a manner sensitive to ODQ but not to 5-HD. A cell-permeable cGMP analog, 8-bromo-cGMP, also reduced H(2)O(2)-induced apoptosis. The inhibition of the H(2)O(2)-induced activation of caspase-3, but not that of caspase-9, by nicorandil in the presence of 5-HD or by SNAP was reversed by the addition of dithiothreitol to the enzyme assay. Nicorandil inhibits oxidative stress-induced apoptosis in cardiac myocytes through a nitric oxide/cGMP-dependent mechanism as well as by activating mitochondrial K(ATP) channels.
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M Morishita, Y Iwasaki, A Onishi, M Asai, N Mutsuga, M Yoshida, Y Oiso, K Inoue, T Murohara (2003)  The effects of GH-releasing hormone/somatostatin on the 5'-promoter activity of the GH gene in vitro.   J Mol Endocrinol 31: 3. 441-448 Dec  
Abstract: The two hypothalamic hormones, GH-releasing hormone (GHRH) and somatostatin (SRIF), are known to regulate GH secretion. However, the effects of these hormones on GH gene expression are not completely clear, partly because of the lack of appropriate host cells maintaining the original characteristics of the somatotroph. Since MtT/S, a pure somatotroph cell line, has become available, the effects of GHRH and SRIF on GH gene transcription have been studied using a subclone of MtT/S (MtT/SGL), in which the GH gene 5'-promoter-luciferase fusion gene was stably incorporated. The expression of GHRH receptor and SRIF receptor subtypes was also studied by RT-PCR. The results showed that MtT/SGL cells intrinsically expressed the functional GHRH receptor and all of the SRIF receptor subtypes. The expression of GHRH receptor was markedly enhanced by glucocorticoid pretreatment and, in the presence of corticosterone and 3-isobutyl-1-methylxanthine, GHRH (at or above 100 pM) stimulated GH gene 5'-promoter activity in a dose-dependent manner. On the other hand, SRIF (100 nM) significantly antagonized the effect of GHRH, which was completely reversed by pretreatment with pertussis toxin (50 ng/ml). Taken together, the present data indicated that both GHRH and SRIF are involved in the transcriptional regulation of the GH gene, and that the effect of SRIF is mediated through pertussis toxin-sensitive G protein. The MtT/SGL cell line is a good in vitro model for studying the molecular mechanisms of GH gene transcription by GHRH and/or SRIF.
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Tadayuki Uetani, Tatsuaki Matsubara, Hideki Nomura, Toyoaki Murohara, Shinsuke Nakayama (2003)  Ca2+-dependent modulation of intracellular Mg2+ concentration with amiloride and KB-R7943 in pig carotid artery.   J Biol Chem 278: 48. 47491-47497 Nov  
Abstract: It has long been recognized that magnesium is associated with several important diseases, including diabetes, hypertension, cardiovascular, and cerebrovascular diseases. In the present study, we measured the intracellular free Mg2+ concentration ([Mg2+]i) using 31P nuclear magnetic resonance (NMR) in pig carotid artery smooth muscle. In normal solution, application of amiloride (1 mm) decreased [Mg2+]i by approximately 12% after 100 min. Subsequent washout tended to further decrease [Mg2+]i. In contrast, application of amiloride significantly increased [Mg2+]i (by approximately 13% after 100 min) under Ca2+-free conditions, where passive Mg2+ influx is facilitated. The treatments had little effect on intracellular ATP and pH (pHi). Essentially the same Ca2+-dependent changes in [Mg2+]i were produced with KB-R7943, a selective blocker of reverse mode Na+-Ca2+ exchange. Application of dimethyl amiloride (0.1 mM) in the presence of Ca2+ did not significantly change [Mg2+]i, although it inhibited Na+-H+ exchange at the same concentration. Removal of extracellular Na+ caused a marginal increase in [Mg2+]i after 100-200 min, as seen in intestinal smooth muscle in which Na+-Mg2+ exchange is known to be the primary mechanism of maintaining a low [Mg2+]i against electrochemical equilibrium. In Na+-free solution (containing Ca2+), neither amiloride nor KB-R7943 decreased [Mg2+]i, but they rather increased it. The results suggest that these inhibitory drugs for Na+-Ca2+ exchange directly modulate Na+-Mg2+ exchange in a Ca2+-dependent manner, and consequently produce the paradoxical decrease in [Mg2+]i in the presence of Ca2+.
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S Isobe, A Ando, M Nanasato, M Nonokawa, H Izawa, T Sobue, M Hirai, K Ito, T Ishigaki, T Murohara, M Yokota (2003)  Combined study with FDG PET and Tl SPECT in patients with idiopathic dilated cardiomyopathy.   Nucl Med Commun 24: 10. 1071-1080 Oct  
Abstract: This study aimed to determine whether combined examinations of myocardial 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) and stress-redistribution 201Tl single-photon emission computed tomography (Tl SPECT) were useful in clarifying myocardial ischaemia and evaluating the prognosis in patients with idiopathic dilated cardiomyopathy (IDCM). Twenty-two patients with IDCM underwent echocardiography, cardiac catheterization, FDG PET, and Tl SPECT. In scintigraphic analysis, the total defect score (TDS) was semiquantitatively determined as the sum of scores of the 17 left ventricular (LV) segments with a 5-point scale (0 as normal to 4 as absent). Patients were classified according to the scintigraphic findings as follows: eight patients with small defects on Tl and FDG (TDS < or = 20) (group I), eight patients with small defects on FDG (TDS < or = 20) with FDG uptake increased relative to Tl or 'mismatch' (group II), and six patients with large defects on FDG and Tl (TDS >20) (group III). Eleven patients (50%) showed reversible defects on Tl and all showed preserved FDG uptake. The patients in group III had significantly lower LV ejection fraction (LVEF) (P<0.05, respectively) and a poorer prognosis as shown by the Kaplan-Meier event-free curve compared with those in groups I and II (P<0.01, respectively). Although patients in group II had significantly greater TDS on Tl compared with those in group I (P<0.01), no significant differences in LVEF and prognosis were found between patients in groups I and II. In multivariate analysis, a TDS on FDG revealed an independent predictor of subsequent cardiac events. In conclusion, such mismatched areas can be assumed to consist of impaired but viable myocardium, and may be associated with ischaemia of the microvasculature. Impaired myocardial glucose metabolism is a more powerful predictor of future cardiac events than perfusion abnormality in patients with IDCM.
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Akihiro Hirashiki, Yoshiji Yamada, Yosuke Murase, Yoriyasu Suzuki, Hiroki Kataoka, Yasutsugu Morimoto, Toru Tajika, Toyoaki Murohara, Mitsuhiro Yokota (2003)  Association of gene polymorphisms with coronary artery disease in low- or high-risk subjects defined by conventional risk factors.   J Am Coll Cardiol 42: 8. 1429-1437 Oct  
Abstract: OBJECTIVES: The aim of the study was to identify genes that confer susceptibility to coronary artery disease (CAD) in low- or high-risk men or women separately and thereby to assess the genetic risk of CAD in such individuals. BACKGROUND: The prevention of CAD would be facilitated by the identification of genes that confer susceptibility to this condition independently in low- or high-risk individuals, as defined by conventional risk factors. METHODS: The study population comprised 1661 unrelated Japanese individuals, including 1011 patients with CAD and 650 control subjects. Among all study subjects, 601 individuals (high-risk subjects) had hypertension, diabetes mellitus, and hypercholesterolemia, and 1060 individuals (low-risk subjects) had none of these risk factors for CAD. The genotypes for 37 polymorphisms of 31 candidate genes were determined by a fluorescence- or colorimetry-based allele-specific DNA primer-probe assay system. RESULTS: Multivariate logistic regression analysis, with adjustment for age, body mass index, and the prevalence of smoking and hyperuricemia, revealed that the -219G-->T polymorphism of the apolipoprotein E gene in low-risk men, the -1171/5A-->6A polymorphism of the stromelysin-1 gene in low-risk women, the 1019C-->T polymorphism of the connexin 37 gene in high-risk men, and the 3932T-->C polymorphism of the apolipoprotein E gene in high-risk women were significantly associated with CAD. A stepwise forward selection procedure revealed that the effects of these polymorphisms on CAD were statistically independent of age or conventional risk factors. CONCLUSIONS: Genotyping of these polymorphisms may prove informative for assessment of the genetic risk of CAD in low- or high-risk men or women.
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Junichiro Kondo, Takahito Sone, Hideyuki Tsuboi, Hiroaki Mukawa, Itsuro Morishima, Michitaka Uesugi, Tomohiro Kono, Takashi Kosaka, Tomohiro Yoshida, Yasushi Numaguchi, Hideo Matsui, Toyoaki Murohara, Kenji Okumura (2003)  Effects of low-dose angiotensin II receptor blocker candesartan on cardiovascular events in patients with coronary artery disease.   Am Heart J 146: 6. Dec  
Abstract: OBJECTIVES: The purpose of this study was to investigate the effects of angiotensin II receptor blockers on the prevention of cardiovascular events in patients with coronary artery disease (CAD). BACKGROUND: Angiotensin II may contribute to the pathogenesis of CAD. Long-term clinical trials have shown that blockade of the renin-angiotensin system can reduce cardiovascular events in patients with acute myocardial infarction complicated by heart failure. METHODS: Patients with a history of coronary intervention and no significant coronary stenosis on follow-up angiography 6 months after intervention were randomly assigned into a candesartan group (n = 203; baseline treatment plus candesartan 4 mg/d) or a control group (n = 203; baseline treatment alone). The primary end point was a composite of revascularization, nonfatal myocardial infarction, or cardiovascular death. The secondary end point was hospitalization for cardiovascular causes. RESULTS: There were no changes in blood pressure and in other coronary risk factors in either group during a mean follow-up of 24 months. Primary end point risk was significantly lower in the candesartan group (n = 12) than in control group patients (n = 25) (P =.03). Candesartan treatment reduced primary end point risk (5.9% vs 12.3% for control subjects; relative risk, 0.47; 95% CI, 0.24 to 0.93). The incidence of all events including secondary end points and noncardiovascular death was significantly lower in the candesartan group than in control group patients (23 vs 40 cases) (P =.02). CONCLUSIONS: Relatively low-dose candesartan, which did not alter blood pressure levels, reduces cardiovascular risk in high-risk patients with CAD.
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Ioakim Spyridopoulos, Corinne Luedemann, Donghui Chen, Marianne Kearney, Dongfen Chen, Toyoaki Murohara, Nicole Principe, Jeffrey M Isner, Douglas W Losordo (2002)  Divergence of angiogenic and vascular permeability signaling by VEGF: inhibition of protein kinase C suppresses VEGF-induced angiogenesis, but promotes VEGF-induced, NO-dependent vascular permeability.   Arterioscler Thromb Vasc Biol 22: 6. 901-906 Jun  
Abstract: Vascular endothelial growth factor (VEGF) promotes angiogenesis by a variety of mechanisms including stimulation of endothelial cell proliferation and migration and increasing vascular permeability. Although its mitogenic activity is mediated primarily by the beta(2)-isoforms of protein kinase C (PKC), little is known about the signaling pathways transducing its other physiological properties. Accordingly, we used a novel inhibitor molecule to examine the role of PKC isoforms alpha and beta in mediating VEGF-induced angiogenesis and vascular permeability. Because conventional inhibitors of PKC, such as staurosporine or calphostin C, also inhibit a variety of other protein kinases, we used a novel compound to specifically inhibit PKC. A myristoylated peptide, which mimics the pseudosubstrate motif of PKC-alpha and -beta subtypes, has been shown to be a highly selective and cell-permeable inhibitor of PKC. Blocking led, as expected, to abrogation of VEGF-induced endothelial cell proliferation in vitro. In vivo, VEGF-induced angiogenesis was impaired by myristoylated peptide. Surprisingly, selective inhibition of PKC induced vascular permeability in vivo via a NO-dependent mechanism. Moreover, PKC inhibition led to a 6.4-fold induction of NO synthase (NOS) activity in endothelial cells. Our findings demonstrate that activation of PKC is a major signaling pathway required for VEGF-induced proliferation and angiogenesis, whereas vascular permeability was enhanced by blocking PKC. Inhibition of calcium-dependent PKC by itself led to induction of NOS. Although NOS is a downstream target for VEGF-induced angiogenesis, its induction by PKC inhibition was not sufficient to promote neovascularization. These results reveal that angiogenesis and vascular permeability induced by VEGF are mediated by mechanisms which ultimately diverge.
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T Sawada, M Hirai, M Akahoshi, Y Inden, Y Yoshida, D Ishihara, K Yamada, Y Takada, T Tanaka, T Kondo, T Murohara (2002)  Ventricular activation and recovery measured in electrocardiographic limb leads correlate with measurements from specific areas in body surface mapping.   Europace 4: 4. 401-410 Oct  
Abstract: AIMS: Dispersion of ventricular depolarization-repolarization in 12-lead electrocardiograms (ECGs) has been reported to provide noninvasive information on arrhythmogenicity. However, there are two methods to calculate the dispersion from ECGs including and excluding limb leads. The aim of this study was to examine whether temporal parameters from limb leads represent activation and repolarization of a particular part of the body surface. METHODS AND RESULTS: We compared the temporal parameters of activation time (AT), activation-recovery interval (ARI), and recovery time (RT) from limb leads of ECGs with those from an 87-lead body surface maps. The study population consisted of 50 normal subjects (25 men and 25 women, 19.4 +/- 1.6 years). The temporal parameters in leads I, II, and III were highly (r > 0.9) correlated with those in unipolar leads over the left lateral, left lower, and right lower chest, respectively. The temporal parameters in leads aVR, aVL, and aVF showed a significant correlation (r > 0.8) with those in unipolar leads over the right upper, left upper, and lower anterior chest, respectively. The mean AT, ARI, and RT from each limb lead of ECG were almost the same as those of unipolar leads over the corresponding areas of the body surface. CONCLUSIONS: These findings suggest that ATs, ARIs, and RTs from limb leads may represent those from unipolar leads of particular areas over the body surface in normal subjects. The temporal parameters from limb leads of ECGs may provide information on activation and repolarization as well as the precordial leads of ECGs.
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Atsushi Katoh, Hisao Ikeda, Yoshinori Takajo, Nobuya Haramaki, Toyoaki Murohara, Satoshi Shintani, Seiji Kanaya, Shinji Yokoyama, Takafumi Ueno, Tomoki Honma, Tsutomu Imaizumi (2002)  Coexistence of impairment of endothelium-derived nitric oxide and platelet-derived nitric oxide in patients with coronary risk factors.   Circ J 66: 9. 837-840 Sep  
Abstract: Impairment of endothelium-derived nitric oxide (EDNO) has been demonstrated in patients with coronary risk factors in some studies, as well as impaired platelet-derived nitric oxide (PDNO) in other studies. However, no study has examined whether these impairments coexist. In 24 patients with coronary risk factors, femoral vascular endothelial function was assessed with acetylcholine (ACh: 50, 100, 200 and 400 microg/min) and endothelium-independent vascular function with nitroglycerin (NTG; 50, 100, 200 microg/min) using a Doppler flow-wire technique, as well as ADP (5 micromol/L)-induced PDNO release with an NO-specific electrode. The ACh-mediated percent change in femoral vascular resistance index (% change of FVRI) and PDNO release had a significant correlation with the number of risk factors. The ACh-mediated % change of FVRI, but not that with NTG, significantly correlated with the PDNO release. Both EDNO and PDNO bioactivities are impaired in patients with coronary risk factors and there is a common mechanism.
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Toyoaki Murohara, Takayuki Asahara (2002)  Nitric oxide and angiogenesis in cardiovascular disease.   Antioxid Redox Signal 4: 5. 825-831 Oct  
Abstract: Ischemic heart disease and peripheral artery disease mainly develop as a consequence of atherosclerotic lesion formation. Angiogenesis, the formation of new blood vessels from the preexisting vascular bed, is of paramount importance in the maintenance of vascular integrity both in the repair process of damaged tissue (wound healing) and in the formation of collateral vessels in response to tissue ischemia. Angiogenesis is a complex process that is orchestrated by a multitude of cytokines/chemokines and growth factors. In its broadest sense, angiogenesis cannot be viewed as a single process. It is likely that different mediators are involved in different phases of angiogenesis. Vascular endothelial cells produce nitric oxide (NO), an endothelium-derived labile molecule, which maintains vascular homeostasis and thereby prevents vascular atherosclerotic changes. In patients with ischemic heart disease and peripheral artery disease, the release of endothelium-derived NO is decreased, which plays an important role in the atherosclerotic disease progression. In recent years, endothelium-derived NO has been shown to modulate angiogenesis in vitro and in vivo. In this review, we summarize recent progress in the field of the NO-mediated regulation of postnatal angiogenesis.
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Ken Sasaki, Toyoaki Murohara, Hisao Ikeda, Takeshi Sugaya, Toshifumi Shimada, Satoshi Shintani, Tsutomu Imaizumi (2002)  Evidence for the importance of angiotensin II type 1 receptor in ischemia-induced angiogenesis.   J Clin Invest 109: 5. 603-611 Mar  
Abstract: The role of the renin-angiotensin system (RAS) in angiogenesis is little known. Here, we show that the angiotensin II (ATII) type 1 (AT1) receptor plays an important role in ischemia-induced angiogenesis. Well-developed collateral vessels and angiogenesis were observed in wild-type (WT) mice in response to hindlimb ischemia, whereas these responses were reduced in ATII type 1a receptor knockout (AT1a(-/-)) mice. Ischemia-induced angiogenesis was also impaired in WT mice treated with the AT1 receptor blocker TCV-116. These effects were not due to reduced systemic blood pressure (SBP), because hydralazine treatment preserved angiogenesis in WT mice although it reduced SBP to a level similar to that of AT1a(-/-) mice. Infiltration of inflammatory mononuclear cells (MNCs), including macrophages and T lymphocytes, was suppressed in the ischemic tissues of AT1a(-/-) mice compared with WT mice. Double immunofluorescence staining revealed that infiltrated macrophages and T lymphocytes expressed VEGF, and the expression of VEGF and monocyte chemoattractant protein-1 was also decreased in AT1a(-/-). Finally, the impaired angiogenesis in AT1a(-/-) mice was rescued by intramuscular transplantation of MNCs obtained from WT mice, further indicating the importance of MNC infiltration in ischemia-induced angiogenesis. Thus, the ATII--AT1 receptor pathway promotes early angiogenesis by supporting inflammatory cell infiltration and angiogenic cytokine expression.
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PMID 
Toyoaki Murohara, Hisao Ikeda, Atsushi Katoh, Yoshinori Takajo, Yoritaka Otsuka, Nobuya Haramaki, Tsutomu Imaizumi (2002)  Vitamin E inhibits lysophosphatidylcholine-induced endothelial dysfunction and platelet activation.   Antioxid Redox Signal 4: 5. 791-798 Oct  
Abstract: Lysophosphatidylcholine (LPC), a lysolipid contained in oxidized low-density lipoprotein, is an atherogenic molecule that induces endothelial dysfunction and platelet activation and inhibits angiogenesis. Although studies showed that vitamin E has antiatherogenic properties, the effects of vitamin E on LPC-induced endothelial dysfunction and platelet activation are little known. We examined whether vitamin E has protecting actions against LPC-induced alterations of endothelial and platelet functions. Incubation of cultured bovine aortic endothelial cells (BAECs) with LPC (10 microM) significantly inhibited bradykinin (1 microM)-stimulated nitric oxide release, which was prevented by cotreatment with vitamin E (50, 100, and 500 microg/ml) in a concentration-dependent manner. In isolated human platelets, LPC stimulated P-selectin expression and induced leukocyte-platelet interaction, which functionally depends on P-selectin expressed on the platelet surface. Vitamin E treatment significantly prevented the LPC-induced platelet P-selectin expression and leukocyte-platelet interaction. As LPC-induced endothelial dysfunction and platelet activation have been shown to involve the protein kinase C (PKC)-dependent signal transduction pathway, we examined the effects of vitamin E on LPC-induced PKC activation in human platelets and BAECs. Vitamin E significantly inhibited LPC (10 microM)-stimulated PKC activation in a concentration-dependent manner. It is concluded that (a) Vitamin E prevented LPC-induced endothelial dysfunction and preserved endothelial nitric oxide release, (b) vitamin E inhibited LPC-induced platelet activation (P-selectin expression) and leukocyte-platelet interaction, and (c) these mechanisms appeared to be at least partly mediated by suppression of the PKC in endothelial cells and platelets. The present findings may provide new insights into antiatherogenic mechanisms of vitamin E.
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PMID 
Eriko Tateishi-Yuyama, Hiroaki Matsubara, Toyoaki Murohara, Uichi Ikeda, Satoshi Shintani, Hiroya Masaki, Katsuya Amano, Yuji Kishimoto, Kohji Yoshimoto, Hidetoshi Akashi, Kazuyuki Shimada, Toshiji Iwasaka, Tsutomu Imaizumi (2002)  Therapeutic angiogenesis for patients with limb ischaemia by autologous transplantation of bone-marrow cells: a pilot study and a randomised controlled trial.   Lancet 360: 9331. 427-435 Aug  
Abstract: BACKGROUND: Preclinical studies have established that implantation of bone marrow-mononuclear cells, including endothelial progenitor cells, into ischaemic limbs increases collateral vessel formation. We investigated efficacy and safety of autologous implantation of bone marrow-mononuclear cells in patients with ischaemic limbs because of peripheral arterial disease. METHODS: We first did a pilot study, in which 25 patients (group A) with unilateral ischaemia of the leg were injected with bone marrow-mononuclear cells into the gastrocnemius of the ischaemic limb and with saline into the less ischaemic limb. We then recruited 22 patients (group B) with bilateral leg ischaemia, who were randomly injected with bone marrow-mononuclear cells in one leg and peripheral blood-mononuclear cells in the other as a control. Primary outcomes were safety and feasibility of treatment, based on ankle-brachial index (ABI) and rest pain, and analysis was per protocol. FINDINGS: Two patients were excluded from group B after randomisation. At 4 weeks in group B patients, ABI was significantly improved in legs injected with bone marrow-mononuclear cells compared with those injected with peripheral blood-mononuclear cells (difference 0.09 [95% CI 0.06-0.11]; p<0.0001). Similar improvements were seen for transcutaneous oxygen pressure (13 [9-17]; p<0.0001), rest pain (-0.85 [-1.6 to -0.12]; p=0.025), and pain-free walking time (1.2 [0.7-1.7]; p=0.0001). These improvements were sustained at 24 weeks. Similar improvements were seen in group A patients. Two patients in group A died after myocardial infarction unrelated to treatment. INTERPRETATION: Autologous implantation of bone marrow-mononuclear cells could be safe and effective for achievement of therapeutic angiogenesis, because of the natural ability of marrow cells to supply endothelial progenitor cells and to secrete various angiogenic factors or cytokines.
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DOI   
PMID 
Kyosuke Takeshita, Koji Yamamoto, Masafumi Ito, Takahisa Kondo, Tadashi Matsushita, Makoto Hirai, Tetsuhito Kojima, Masahiko Nishimura, Yoichi Nabeshima, David J Loskutoff, Hidehiko Saito, Toyoaki Murohara (2002)  Increased expression of plasminogen activator inhibitor-1 with fibrin deposition in a murine model of aging, "Klotho" mouse.   Semin Thromb Hemost 28: 6. 545-554 Dec  
Abstract: Although aging accompanies specific pathological changes, including thrombosis and organ sclerosis, the underlying mechanisms of these processes remain to be elucidated. In the present study, we analyzed the gene expression of plasminogen activator inhibitor-1 (PAI-1), a key molecule in the development of thrombosis, in a murine model of aging, klotho mutant ( kl/kl) mice. Active PAI-1 antigen in plasma and PAI-1 mRNA in several tissues were strikingly elevated in kl/kl mice as compared with wild-type mice. This increased PAI-1 expression was age dependent and linked to the development of ectopic calcification and glomerular fibrin deposition in the kidneys. In situ hybridization analysis of kl/kl mice demonstrated that strong signals for PAI-1 mRNA were localized in renal tubular epithelial cells, cardiomyocytes, adrenal medullar cells, and smooth muscle and endothelial cells in Mönckeberg's arteriosclerotic vessels. Renal glomerular fibrin deposition, as evaluated immunohistochemically, was occasionally observed only in kl/kl mice, and the number of fibrin-positive glomeruli increased as the kl/kl mice aged. These observations suggest that in the process of aging the PAI-1 gene expression is increased, contributing to the development of thrombosis.
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2001
 
PMID 
S Shintani, T Murohara, H Ikeda, T Ueno, T Honma, A Katoh, K Sasaki, T Shimada, Y Oike, T Imaizumi (2001)  Mobilization of endothelial progenitor cells in patients with acute myocardial infarction.   Circulation 103: 23. 2776-2779 Jun  
Abstract: BACKGROUND: Endothelial progenitor cells (EPCs) circulate in adult peripheral blood (PB) and contribute to neovascularization. However, little is known regarding whether EPCs and their putative precursor, CD34-positive mononuclear cells (MNC(CD34+)), are mobilized into PB in acute ischemic events in humans. METHODS AND RESULTS: Flow cytometry revealed that circulating MNC(CD34+) counts significantly increased in patients with acute myocardial infarction (n=16), peaking on day 7 after onset, whereas they were unchanged in control subjects (n=8) who had no evidence of cardiac ischemia. During culture, PB-MNCs formed multiple cell clusters, and EPC-like attaching cells with endothelial cell lineage markers (CD31, vascular endothelial cadherin, and kinase insert domain receptor) sprouted from clusters. In patients with acute myocardial infarction, more cell clusters and EPCs developed from cultured PB-MNCs obtained on day 7 than those on day 1. Plasma levels of vascular endothelial growth factor significantly increased, peaking on day 7, and they positively correlated with circulating MNC(CD34+) counts (r=0.35, P=0.01). CONCLUSIONS: This is the first clinical demonstration showing that lineage-committed EPCs and MNC(CD34+), their putative precursors, are mobilized during an acute ischemic event in humans.
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PMID 
S Shintani, T Murohara, H Ikeda, T Ueno, K Sasaki, J Duan, T Imaizumi (2001)  Augmentation of postnatal neovascularization with autologous bone marrow transplantation.   Circulation 103: 6. 897-903 Feb  
Abstract: BACKGROUND: Endothelial progenitor cells (EPCs) have been identified in adult human peripheral blood. Because circulating EPCs should originate from bone marrow (BM), we examined whether BM mononuclear cells (BM-MNCs) can give rise to functional EPCs and whether transplantation of autologous BM-MNCs might augment angiogenesis and collateral vessel formation in a rabbit model of hindlimb ischemia. METHODS AND RESULTS: Rabbit BM-MNCs were isolated by centrifugation through a Histopaque density gradient and cultured on fibronectin. EPCs developed from BM-MNCs in vitro, as assessed by acetylated LDL incorporation, nitric oxide (NO) release, and expression of von Willebrand factor and lectin binding. Unilateral hindlimb ischemia was surgically induced in rabbits (n=8), and fluorescence-labeled autologous BM-MNCs were transplanted into the ischemic tissues. Two weeks after transplantation, fluorescence microscopy revealed that transplanted cells were incorporated into the capillary network among preserved skeletal myocytes. In contrast, transplanted autologous BM-fibroblasts did not participate in EC capillary network formation (n=5). Then, in an additional 27 rabbits, saline (control; n=8), autologous BM-MNCs (n=13; 6.9+/-2.2x10(6) cells/animal), or BM-fibroblasts (n=6; 6.5+/-1.5x10(6) cells/animal) were injected into the ischemic tissues at postoperative day 7. Four weeks after transplantation, the BM-MNC-transplanted group had more angiographically detectable collateral vessels (angiographic score: 1.5+/-0.34 versus 0.94+/-0.26 and 1.1+/-0.14; P:<0.05), a higher capillary density (23+/-5.8 versus 10+/-1.9 and 11+/-0.8 per field; P:<0.001), and a greater laser Doppler blood perfusion index (505+/-155 versus 361+/-35 and 358+/-22 U; P:<0.05) than the control and BM-fibroblast-transplanted groups. CONCLUSIONS: Direct local transplantation of autologous BM-MNCs seems to be a useful strategy for therapeutic neovascularization in ischemic tissues in adults, consistent with "therapeutic vasculogenesis."
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PMID 
H Kamihata, H Matsubara, T Nishiue, S Fujiyama, Y Tsutsumi, R Ozono, H Masaki, Y Mori, O Iba, E Tateishi, A Kosaki, S Shintani, T Murohara, T Imaizumi, T Iwasaka (2001)  Implantation of bone marrow mononuclear cells into ischemic myocardium enhances collateral perfusion and regional function via side supply of angioblasts, angiogenic ligands, and cytokines.   Circulation 104: 9. 1046-1052 Aug  
Abstract: BACKGROUND: Bone marrow implantation (BMI) was shown to enhance angiogenesis in a rat ischemic heart model. This preclinical study using a swine model was designed to test the safety and therapeutic effectiveness of BMI. METHODS AND RESULTS: BM-derived mononuclear cells (BM-MNCs) were injected into a zone made ischemic by coronary artery ligation. Three weeks after BMI, regional blood flow and capillary densities were significantly higher (4.6- and 2.8-fold, respectively), and cardiac function was improved. Angiography revealed that there was a marked increase (5.7-fold) in number of visible collateral vessels. Implantation of porcine coronary microvascular endothelial cells (CMECs) did not cause any significant increase in capillary densities. Labeled BM-MNCs were incorporated into approximately 31% of neocapillaries and corresponded to approximately 8.7% of macrophages but did not actively survive as myoblasts or fibroblasts. There was no bone formation by osteoblasts or malignant ventricular arrhythmia. Time-dependent changes in plasma levels for cardiac enzymes (troponin I and creatine kinase-MB) did not differ between the BMI, CMEC, and medium-alone implantation groups. BM-MNCs contained 16% of endothelial-lineage cells and expressed basic fibroblast growth factor>>vascular endothelial growth factor>angiopoietin 1 mRNAs, and their cardiac levels were significantly upregulated by BMI. Cardiac interleukin-1beta and tumor necrosis factor-alpha mRNA expression were also induced by BMI but not by CMEC implantation. BM-MNCs were actively differentiated to endothelial cells in vitro and formed network structure with human umbilical vein endothelial cells. CONCLUSIONS: BMI may constitute a novel safety strategy for achieving optimal therapeutic angiogenesis by the natural ability of the BM cells to secrete potent angiogenic ligands and cytokines as well as to be incorporated into foci of neovascularization.
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PMID 
H Urano, H Ikeda, T Ueno, T Matsumoto, T Murohara, T Imaizumi (2001)  Enhanced external counterpulsation improves exercise tolerance, reduces exercise-induced myocardial ischemia and improves left ventricular diastolic filling in patients with coronary artery disease.   J Am Coll Cardiol 37: 1. 93-99 Jan  
Abstract: OBJECTIVES: We examined whether enhanced external counterpulsation (EECP) improves myocardial ischemia, exercise tolerance and cardiac function in patients with coronary artery disease (CAD). BACKGROUND: Enhanced external counterpulsation reduces angina and improves exercise tolerance in patients with CAD. Some objective improvements of ischemia by EECP have been reported, but they should be confirmed further. Detailed hemodynamic effects of EECP have been less well documented. METHODS: Enhanced external counterpulsation was performed for a total of 35 h in patients with stable CAD (n = 12) who showed evidence of exercise-induced myocardial ischemia despite conventional medical or surgical therapies. All patients had significant stenotic lesions in major coronary arteries. RESULTS: Enhanced external counterpulsation improved all exercise test parameters (p < 0.05): exercise duration, time to 1-mm ST segment depression, rate-pressure product at peak exercise and rate-pressure product at 1-mm ST segment depression. Moreover, the prevalence of exercise-induced reversible perfusion defects by thallium scintigraphy decreased after treatment (p < 0.01). Enhanced external counterpulsation did not alter systolic function but improved diastolic filling, left ventricular (LV) end-diastolic pressure (p < 0.05) by cardiac catheterization and LV peak filling rate end-diastolic volume/s (p < 0.01) and time to peak filling rate (p < 0.05) by radionuclide scintigraphy. These hemodynamic improvements were associated with decreased plasma brain natriuretic peptides levels after EECP (p < 0.05). CONCLUSIONS: Thus, EECP treatment improves exercise tolerance and reduced myocardial ischemia by thallium scintigraphy in association with improved LV diastolic filling in patients with stable CAD.
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PMID 
S Kanaya, H Ikeda, N Haramaki, T Murohara, T Imaizumi (2001)  Intraplatelet tetrahydrobiopterin plays an important role in regulating canine coronary arterial thrombosis by modulating intraplatelet nitric oxide and superoxide generation.   Circulation 104: 20. 2478-2484 Nov  
Abstract: BACKGROUND: Platelet-derived nitric oxide inhibits platelet aggregation via constitutive NO synthase (NOS). Tetrahydrobiopterin (BH(4)), a cofactor of NOS, augments NO formation, whereas its deficiency decreases NO bioactivity and increases superoxide generation by NOS. The roles of intraplatelet BH(4) in platelet aggregation and thrombus formation, however, are unknown. Accordingly, we investigated whether intraplatelet BH(4) is involved in regulating cyclic flow variations (CFVs) and platelet aggregation in a canine model with stenosed and endothelium-injured coronary arteries that mimics acute coronary syndromes in humans. METHODS AND RESULTS: After developing CFVs, dogs received saline or BH(4) (10 or 30 mg/kg) intravenously. Intraplatelet BH(4) and cGMP levels were decreased and intraplatelet nitrotyrosine production was increased during CFVs. ADP- and U46619-induced ex vivo platelet aggregation and platelet P-selectin expression were augmented during CFVs. BH(4) administration restored intraplatelet BH(4) and cGMP levels and decreased intraplatelet nitrotyrosine production, resulting in reduced CFVs and inhibited ex vivo platelet aggregation and platelet P-selectin expression. CFVs again developed after N(G)-monomethyl-L-arginine, an inhibitor of NOS, in BH(4)-treated dogs. Ex vivo platelet NOS activity at baseline, during CFVs, and after BH(4) administration did not differ. CONCLUSIONS: Intraplatelet BH(4) may play an important role in regulating thrombus formation by modulating platelet-derived nitric oxide and superoxide generation by platelet NOS.
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PMID 
Y Takajo, H Ikeda, N Haramaki, T Murohara, T Imaizumi (2001)  Augmented oxidative stress of platelets in chronic smokers. Mechanisms of impaired platelet-derived nitric oxide bioactivity and augmented platelet aggregability.   J Am Coll Cardiol 38: 5. 1320-1327 Nov  
Abstract: OBJECTIVES: We investigated whether impaired platelet-derived nitric oxide (PDNO) bioactivity and augmented platelet aggregability in chronic smokers are related to the imbalance of the intraplatelet redox state through increased oxidative stress. BACKGROUND: Chronic smoking impairs PDNO release and augments platelet aggregability. However, their mechanisms are unknown. METHODS: Collagen-induced PDNO release, platelet aggregation, plasma and intraplatelet vitamin C and reduced glutathione (GSH), intraplatelet cyclic guanosine 3',5'-monophosphate (cGMP) and intraplatelet nitrotyrosine production, which is a marker of the peroxynitrite formation, were measured in 11 chronic smokers and 10 age-matched nonsmokers. RESULTS: Release of PDNO and levels of intraplatelet cGMP were lower, and platelet aggregation was greater, in smokers than in nonsmokers. Intraplatelet vitamin C and GSH levels were lower in smokers than in nonsmokers. Intraplatelet nitrotyrosine production was greater in smokers than in nonsmokers. Next, we investigated the effects of oral vitamin C administration (2 g). After vitamin C administration, intraplatelet vitamin C levels were increased and not different at 2 h between the two groups. Then, PDNO release, intraplatelet cGMP levels and platelet aggregation in smokers were restored to the levels of nonsmokers. In smokers, PDNO release and consumption of GSH during platelet aggregation were inversely correlated, and consumption was much less after vitamin C administration. Vitamin C administration decreased intraplatelet nitrotyrosine production in smokers. CONCLUSIONS: Impaired PDNO bioactivity and augmented platelet aggregability may be caused by an imbalance of the intraplatelet redox state through increased oxidative stress in smokers.
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PMID 
T Murohara (2001)  Therapeutic vasculogenesis using human cord blood-derived endothelial progenitors.   Trends Cardiovasc Med 11: 8. 303-307 Nov  
Abstract: Peripheral blood of adult species contains endothelial progenitor cells (EPCs) that participate in neovascularization, consistent with postnatal vasculogenesis. Abundant EPCs can be isolated from a relatively small volume of human umbilical cord blood, and that culture-expanded EPCs participate in endothelial network formation in vitro. Transplanted EPCs incorporated into sites of active neovascularization and formed capillaries among preserved skeletal myocytes in the ischemic hindlimb of athymic nude rats in vivo. Furthermore, transplantation of EPC quantitatively and effectively augmented neovascularization in response to hindlimb ischemia. Thus, human umbilical cord blood seems to be a novel source for EPCs, and the transplantation of cord blood-derived EPCs may become a useful strategy to modulate postnatal neovascularization.
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PMID 
N Haramaki, H Ikeda, Y Takajo, A Katoh, S Kanaya, S Shintani, R Haramaki, T Murohara, T Imaizumi (2001)  Long-term smoking causes nitroglycerin resistance in platelets by depletion of intraplatelet glutathione.   Arterioscler Thromb Vasc Biol 21: 11. 1852-1856 Nov  
Abstract: We investigated whether platelet responsiveness to nitroglycerin (NTG) is maintained in long-term smokers and if not, the mechanism. In the absence or presence of NTG, intraplatelet reduced glutathione (GSH) levels and ADP-induced platelet aggregation and intraplatelet cGMP levels were measured in 10 long-term smokers and 10 age-matched nonsmokers. The intraplatelet GSH level was significantly lower in smokers than in nonsmokers (P<0.05). Platelet aggregation was dose-dependently inhibited by NTG in both groups; however, inhibition was significantly weaker in smokers. N-acetylcysteine (1 mmol/L), an exogenous thiol agent, significantly potentiated NTG-induced platelet inhibition in nonsmokers but not in smokers. The ADP-induced intraplatelet cGMP level was significantly greater in the presence of NTG in nonsmokers but not so in smokers. Because the effects of long-term smoking are multifactorial, a rabbit model was made by chronic administration of buthionine sulfoximine (BSO, n=6) to decrease intraplatelet GSH. The intraplatelet GSH level was significantly lower in BSO-treated rabbits than in saline-treated rabbits (P<0.001). The NTG-induced inhibition of platelet aggregation was significantly weaker in BSO rabbits. N-acetylcysteine-induced potentiation was not observed in BSO rabbits, whereas significant potentiation was found in saline rabbits. These findings were similar to those of long-term smokers. In contrast, the intraplatelet GSH-to-oxidized glutathione ratio, which represents the redox state of glutathione, was significantly lower in smokers than in nonsmokers, whereas no difference was found between saline rabbits and BSO rabbits. In conclusion, long-term smoking causes NTG resistance to aggregation in platelets, possibly through the depletion of intraplatelet GSH.
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2000
 
PMID 
T Murohara, H Ikeda, J Duan, S Shintani, K i Sasaki, H Eguchi, I Onitsuka, K Matsui, T Imaizumi (2000)  Transplanted cord blood-derived endothelial precursor cells augment postnatal neovascularization.   J Clin Invest 105: 11. 1527-1536 Jun  
Abstract: Endothelial precursor cells (EPCs) have been identified in adult peripheral blood. We examined whether EPCs could be isolated from umbilical cord blood, a rich source for hematopoietic progenitors, and whether in vivo transplantation of EPCs could modulate postnatal neovascularization. Numerous cell clusters, spindle-shaped and attaching (AT) cells, and cord-like structures developed from culture of cord blood mononuclear cells (MNCs). Fluorescence-trace experiments revealed that cell clusters, AT cells, and cord-like structures predominantly were derived from CD34-positive MNCs (MNC(CD34+)). AT cells and cell clusters could be generated more efficiently from cord blood MNCs than from adult peripheral blood MNCs. AT cells incorporated acetylated-LDL, released nitric oxide, and expressed KDR, VE-cadherin, CD31, and von Willebrand factor but not CD45. Locally transplanted AT cells survived and participated in capillary networks in the ischemic tissues of immunodeficient nude rats in vivo. AT cells thus had multiple endothelial phenotypes and were defined as a major population of EPCs. Furthermore, laser Doppler and immunohistochemical analyses revealed that EPC transplantation quantitatively augmented neovascularization and blood flow in the ischemic hindlimb. In conclusion, umbilical cord blood is a valuable source of EPCs, and transplantation of cord blood-derived EPCs represents a promising strategy for modulating postnatal neovascularization.
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PMID 
H Ikeda, Y Takajo, T Murohara, K Ichiki, H Adachi, N Haramaki, A Katoh, T Imaizumi (2000)  Platelet-derived nitric oxide and coronary risk factors.   Hypertension 35: 4. 904-907 Apr  
Abstract: Platelet aggregation is inhibited through a negative feedback mechanism by the L-arginine/nitric oxide (NO) pathway found in platelets themselves. We have shown that long-term smoking impairs the bioactivity of platelet-derived NO (PDNO), resulting in an increased platelet aggregability. However, little is known about the relation between other coronary risk factors and PDNO release. Accordingly, this study was undertaken to examine whether other coronary risk factors are related to the impairment of PDNO bioactivity. We measured collagen-induced PDNO release with an NO-selective electrode in 61 subjects (mean age 47 years, range 24 to 74 years) who underwent complete physical and laboratory examinations. There was a significant inverse correlation between PDNO release and the number of coronary risk factors (r=-0.61, P<0. 001). Univariate analysis showed a significant inverse correlation between PDNO release and age (r=-0.33, P<0.01), mean arterial pressure (r=-0.40, P<0.002), total cholesterol level (r=-0.31, P<0. 02), and LDL-cholesterol level (r=-0.33, P<0.02). PDNO release was significantly lower in long-term smokers than in nonsmokers (P<0. 001). With multiple stepwise regression analysis, PDNO release correlated significantly and independently (r(2)=0.51), with smoking (F=37.8), age (F=7.1), and mean arterial pressure (F=5.1). Thus, we demonstrated that coronary risk factors are associated with an impairment of PDNO release by human platelets. Our findings may contribute to the understanding of the pathophysiological link between coronary risk factors and atherothrombotic disease.
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PMID 
T Murohara, S Kamijikkoku, T Honda (2000)  Increased circulating soluble intercellular adhesion molecule-1 in acute myocardial infarction: a possible predictor of reperfusion ventricular arrhythmias.   Crit Care Med 28: 6. 1861-1864 Jun  
Abstract: OBJECTIVES: Myocardial ischemia/reperfusion induces ventricular reperfusion arrhythmias (RAs). Significant parts of RAs are considered to be evoked by oxygen free radicals. Inasmuch as activated leukocytes release oxygen free radicals, and as the intercellular adhesion molecule-1 (ICAM-1) plays a major role in leukocyte infiltration, we examined whether there may be a relationship between plasma levels of soluble ICAM-1 (sICAM-1) and frequency of RAs in patients with acute myocardial infarction (AMI). DESIGN: Prospective study comparing the two AMI patient groups with or without RAs. SETTING: Coronary care unit and cardiac catheterization laboratories in a general hospital. PATIENTS: Twenty-three AMI patients (eight women and 15 men, aged 32 to 79 yrs). INTERVENTIONS: All patients received percutaneous balloon angioplasty with or without previous intracoronary thrombolysis. Significant RAs were defined as at least one of nonsustained ventricular tachycardia, multifocal premature ventricular contraction, and frequent premature ventricular contraction occurring >15 times/min, which were not observed before reperfusion. MEASUREMENTS AND MAIN RESULTS: Plasma sICAM-1 levels were measured using an enzyme-linked immunosorbent assay. The plasma sICAM-1 levels at admission were significantly greater in RA(+) (243 +/- 60 ng/mL) than RA(-) group (192 +/- 44 ng/mL) (p < .05). We followed plasma sICAM-1 levels up to 3 wks, and found that sICAM-1 levels were consistently higher in the RA(+) than the RA(-) group. Simple regression analysis showed no significant relationship between plasma sICAM-1 levels and age, systolic and diastolic blood pressures, or serum creatine kinase activity. The two AMI groups showed no differences in age, gender, events of major coronary risk factors, preinfarction angina, and medication. CONCLUSIONS: The increase in the plasma levels of sICAM-1 was observed in patients manifesting ventricular RAs. This increase in sICAM-1 levels was observed as early as at admission. The increased plasma sICAM-1 levels may be a useful biochemical marker for predicting myocardial reperfusion injury such as RAs in AMI.
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PMID 
A Shiraishi, H Ikeda, N Haramaki, T Murohara, T Matsumoto, T Ueno, T Imaizumi (2000)  Abnormal myocardial blood flow distribution in patients with angina pectoris and normal coronary arteriograms.   Jpn Circ J 64: 8. 566-571 Aug  
Abstract: To evaluate coronary microvascular function and its relation to the genesis of chest pain and ST-segment depression during exercise in patients with syndrome X, pacing-induced changes in transmural myocardial blood flow distribution were quantitatively assessed by 2-dimensional myocardial contrast echocardiography. Of 25 patients with a history of chest pain and normal coronary arteries with the negative ergonovine test, 11 had exercise-induced chest pain and ST-segment depression (syndrome X), and 14 did not (controls). Myocardial blood flow distribution before and after pacing stress was assessed by measuring the ratio of the endocardial to epicardial gray level (ie, endo/epi gray level ratio) in the territory of the left anterior descending coronary artery. Pacing-induced chest pain and ST-segment depression were observed in syndrome X, but not in controls. The endo/epi gray level ratio in syndrome X significantly decreased after pacing (from 0.98+/-0.10 to 0.76+/-0.17, p<0.01), but not in controls (from 0.97+/-0.08 to 0.99+/-0.08, NS). Abnormal myocardial blood flow distribution may play an important role in exercise-induced chest pain and ST-segment depression in these patients.
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PMID 
J Duan, T Murohara, H Ikeda, K Sasaki, S Shintani, T Akita, T Shimada, T Imaizumi (2000)  Hyperhomocysteinemia impairs angiogenesis in response to hindlimb ischemia.   Arterioscler Thromb Vasc Biol 20: 12. 2579-2585 Dec  
Abstract: Hyperhomocysteinemia (HH) is an independent risk factor for atherosclerosis, including peripheral arterial occlusive disease (PAOD). Because angiogenesis and collateral vessel formation are important self-salvage mechanisms for ischemic PAOD, we examined whether HH modulates angiogenesis in vivo in a rat model of hindlimb ischemia. Rats were divided into 3 groups: the control group was given tap water, the HH group was given water containing L-methionine (1 g x kg(-1) x d(-1)), and the HH+L-arg group was given water containing methionine (1 g x kg(-1) x d(-1)) and l-arginine (2.25 vol%). At day 14 of the dietary modifications, the left femoral artery and vein were excised, and the extent of angiogenesis and collateral vessels in the ischemic limb were examined for 4 weeks. Plasma homocysteine levels significantly increased (P:<0.001), and plasma and tissue contents of nitrite+nitrate as well as tissue cGMP levels significantly decreased in the HH group compared with the control group (P:<0.01). Laser Doppler blood flowmetry (LDBF) revealed a significant decrease in the ischemic/normal limb LDBF ratio in the HH group at days 7, 14, 21, and 28 (P:<0.01 versus control). Angiography revealed a significant decrease in the angiographic score in the HH group at day 14 (P:<0.001 versus control). Immunohistochemistry of ischemic tissue sections showed a significant reduction in the capillary density in the HH group (P:<0. 001 versus control). Oral l-arginine supplementation in rats with HH (HH+L-arg) restored the decreased plasma and tissue nitrite+nitrate and cGMP contents (P:<0.05) as well as angiogenesis, as assessed by LDBF (P:<0.05 versus HH), angiographic score (P:<0.01 versus HH), and capillary density (P:<0.001 versus HH). In summary, HH impaired ischemia-induced angiogenesis and collateral vessel formation in a rat model of hindlimb ischemia in vivo. The mechanism of the HH-induced impairment of angiogenesis might be mediated in part by a reduced bioactivity of endogenous NO in the HH state.
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PMID 
J Duan, T Murohara, H Ikeda, A Katoh, S Shintani, K Sasaki, H Kawata, N Yamamoto, T Imaizumi (2000)  Hypercholesterolemia inhibits angiogenesis in response to hindlimb ischemia: nitric oxide-dependent mechanism.   Circulation 102: 19 Suppl 3. III370-III376 Nov  
Abstract: BACKGROUND: Endothelium-derived nitric oxide (EDNO) plays an important role in the regulation of angiogenesis, whereas hypercholesterolemia (HC) impairs EDNO release. We examined the hypothesis that HC may inhibit ischemia-induced angiogenesis by inhibition of EDNO in a rat model of unilateral hindlimb ischemia and that oral L-arginine supplementation, a substrate for NO synthase, may prevent HC-related impairment of angiogenesis. METHODS AND RESULTS: Male Sprague-Dawley rats were fed (A) standard diet (control), (B) 2% high-cholesterol diet (HC group), or (C) high-cholesterol diet with oral L-arginine (2.25% in drinking water) (HC+L-arg group). At 2 weeks of the dietary intervention, unilateral limb ischemia was surgically induced in all animals. Dietary HC groups (B and C) revealed elevated total and LDL cholesterol levels compared with control animals. Laser Doppler blood flow analyses showed significant decreases in the ischemic/normal limb blood flow ratio in the HC group compared with controls (P:<0.05) when followed up until 4 weeks after surgery. Selective angiography and immunohistochemical analyses in the ischemic limb at postoperative day 14 revealed significantly lower angiographic scores (P:<0.01) and capillary densities (P:<0.01) in the HC group than controls, which were associated with decreased tissue contents of NO(x) and cGMP. Oral L-arginine supplementation (HC+L-arg) significantly improved all parameters of the laser Doppler blood perfusion ratio, angiographic scores, and capillary densities (P:<0.01 versus HC group), which were accompanied by significant elevations in serum L-arginine levels and tissue NO(x) and cGMP contents. CONCLUSIONS: Collateral vessel formation and angiogenesis in response to hindlimb ischemia were significantly attenuated in rats with dietary HC. The mechanism may be related to the reduced NO bioactivity in the ischemic tissues. Augmentation of the tissue NO activity by oral L-arginine supplementation restored the impaired angiogenesis in HC.
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1999
 
PMID 
H Ikeda, T Ueyama, T Murohara, H Yasukawa, N Haramaki, H Eguchi, A Katoh, Y Takajo, I Onitsuka, T Ueno, S J Tojo, T Imaizumi (1999)  Adhesive interaction between P-selectin and sialyl Lewis(x) plays an important role in recurrent coronary arterial thrombosis in dogs.   Arterioscler Thromb Vasc Biol 19: 4. 1083-1090 Apr  
Abstract: Cell adhesion molecules may play an important role in the disease process of acute coronary syndromes. We have shown a neutralizing anti-P-selectin monoclonal antibody and a sialyl Lewis(x)-containing oligosaccharide (SLe(x)-OS), an analogue of selectin ligand on leukocytes, reduce cyclic flow variations (CFVs) in a canine model of recurrent coronary arterial thrombosis, suggesting the important interaction between P-selectin and SLex for the pathophysiology of these syndromes. However, the functional role of these adhesion molecules in the thrombotic process remains unclear. Therefore, we investigated effects of SLe(x)-OS on CFVs, platelet P-selectin expression, and morphology of the stenotic site in the same model. Anesthetized open-chest dogs (n=34) were randomly divided into 4 groups after developing CFVs. Dogs intravenously received saline or graded doses of SLe(x)-OS (5, 20, or 40 mg/kg bolus) infusion followed by a continuous infusion (5 mg. kg-1. h-1) for 60 minutes. By flow cytometric analysis, P-selectin expression on platelets after CFVs was significantly upregulated during CFVs. Immunohistochemical analysis revealed the incorporation of platelets with upregulated P-selectin within thrombi at the stenotic site. Microscopic observations revealed the presence of numerous platelets adhered to leukocytes at the stenotic site on the damaged endothelium. SLe(x)-OS significantly reduced CFVs, inhibited the P-selectin expression on platelets, and prevented the adherence of platelets and leukocytes. These findings further support the notion that the adhesive interaction between P-selectin on platelets and SLe(x) on leukocytes plays an important role in platelet-mediated thrombus formation in this model.
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PMID 
H Eguchi, H Ikeda, T Murohara, H Yasukawa, N Haramaki, S Sakisaka, T Imaizumi (1999)  Endothelial injuries of coronary arteries distal to thrombotic sites: role of adhesive interaction between endothelial P-selectin and leukocyte sialyl LewisX.   Circ Res 84: 5. 525-535 Mar  
Abstract: Intracoronary thrombus formation is associated with epicardial vasoconstriction distal to the thrombotic site. To investigate the mechanisms of abnormal vasomotor function of the artery distal to the thrombotic site, we studied coronary vessels in dogs with cyclic flow variations (CFVs) of the left anterior descending coronary artery (LAD) stenosis with endothelial injury. Coronary rings isolated from the LAD (proximal, stenotic, and distal sites) and control circumflex coronary arteries were tested for responsiveness to endothelium-dependent (acetylcholine and A23187) and endothelium-independent vasodilators (NaNO2). Endothelium-independent relaxation was intact in all 4 sites. Endothelium-dependent relaxation was intact in the control and proximal sites and impaired in the stenotic sites. Relaxations not only to acetylcholine and A23187 but also to serotonin, ADP, and thrombin were impaired in the distal sites after observing CFVs for 80 minutes. Electron microscopy revealed the loss of endothelial integrity with leukocyte adherence to the endothelium in the distal sites. Immunohistochemical expression of P-selectin on the endothelial cells was more upregulated in the distal site than in the proximal site, and P-selectin mRNA expression was significantly greater in the ischemic region distal to the thrombotic site than in the proximal nonischemic region. PB1.3, a neutralizing monoclonal antibody against P-selectin, and sialyl LewisX (SLeX)-containing oligosaccharide SLeX, a carbohydrate analogue of selectin ligand, preserved endothelial function without affecting CFVs. SLeX-containing oligosaccharide preserved endothelial integrity of the distal site and inhibited P-selectin expression of the distal site. Thus, the adhesive interaction between endothelial P-selectin and leukocyte SLeX may play an important role in endothelial injuries of the coronary artery distal to the thrombotic site.
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PMID 
H Ikeda, S Maki, N Yoshida, T Murohara, H Adachi, Y Koga, T Imaizumi (1999)  Predictors of death from congestive heart failure in hypertrophic cardiomyopathy.   Am J Cardiol 83: 8. 1280-3, A9 Apr  
Abstract: In 309 patients with hypertrophic cardiomyopathy during long-term follow-up (mean 9.4 years), independent predictors of death from congestive heart failure (n = 15) were smaller electrocardiographic SV1 + RV5 and smaller echocardiographic fractional shortening at the initial evaluation. Our data may contribute to the construction of therapeutic strategies for the prevention of heart failure death in patients with hypertrophic cardiomyopathy.
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PMID 
A Rivard, J E Fabre, M Silver, D Chen, T Murohara, M Kearney, M Magner, T Asahara, J M Isner (1999)  Age-dependent impairment of angiogenesis.   Circulation 99: 1. 111-120 Jan  
Abstract: BACKGROUND: The effect of aging on angiogenesis in ischemic vascular disease has not been studied. Accordingly, we investigated the hypothesis that angiogenesis is impaired as a function of age. METHODS AND RESULTS: Forty days after the resection of 1 femoral artery, collateral vessel development was significantly impaired in old (aged 4 to 5 years; n=7) versus young (aged 6 to 8 months; n=6) New Zealand White (NZW) rabbits on the basis of reduced hindlimb perfusion (ischemic: normal blood pressure ratio=0.58+/-0.05 versus 0.77+/-0.06; P<0.005), reduced number of angiographically visible vessels (angiographic score=0.48+/-0.05 versus 0.70+/-0.05; P<0.01), and lower capillary density in the ischemic limb (130.3+/-5.8/mm2 versus 171.4+/-9.5/mm2; P<0.001). Angiogenesis was also impaired in old (aged 2 years) versus young (aged 12 weeks) mice as shown by reduced hindlimb perfusion (measured by laser Doppler imaging) and lower capillary density (353.0+/-14.3/mm2 versus 713.3+/-63.4/mm2; P<0.01). Impaired angiogenesis in old animals was the result of impaired endothelial function (lower basal NO release and decreased vasodilation in response to acetylcholine) and a lower expression of vascular endothelial growth factor (VEGF) in ischemic tissues (by Northern blot, Western blot, and immunohistochemistry). When recombinant VEGF protein was administered to young and old rabbits, both groups exhibited a significant and similar increase in blood pressure ratio, angiographic score, and capillary density. CONCLUSIONS: Angiogenesis responsible for collateral development in limb ischemia is impaired with aging; responsible mechanisms include age-related endothelial dysfunction and reduced VEGF expression. Advanced age, however, does not preclude augmentation of collateral vessel development in response to exogenous angiogenic cytokines.
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PMID 
T Ueno, H Kai, H Ikeda, T Matsumoto, T Murohara, N Haramaki, H Eguchi, A Kato, Y Takajo, I Onitsuka, T Imaizumi (1999)  Coronary sinus long sheath catheter system: a new device for transfemoral coronary sinus catheterization.   Heart Vessels 14: 4. 201-204  
Abstract: Coronary sinus catheterization requires an approach into the right atrium via the superior vena cava. This study contains information regarding a coronary sinus long sheath catheter (CS sheath) system, a new device for cannulation of the coronary sinus through the femoral approach. This method was successful in 96.9% of the cases attempted. Furthermore, cannulation using the CS sheath allowed us not only to insert several catheters into the coronary sinus for clinical use and investigation, but also to access the great and small cardiac veins easily and selectively.
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PMID 
T Murohara, B Witzenbichler, I Spyridopoulos, T Asahara, B Ding, A Sullivan, D W Losordo, J M Isner (1999)  Role of endothelial nitric oxide synthase in endothelial cell migration.   Arterioscler Thromb Vasc Biol 19: 5. 1156-1161 May  
Abstract: Endothelium-derived nitric oxide (NO) and its precursor L-arginine have been implied to promote angiogenesis, but little is known about the precise mechanism. The inhibition of endogenous NO formation by Nomega-nitro-L-arginine methyl ester (L-NAME) (1 mmol/L) but not its inactive enantiomer D-NAME (1 mmol/L) inhibited endothelial cell sprouting from the scratched edge of the cultured bovine aortic endothelial cell monolayer. Inhibition of endogenous NO release by L-NAME was confirmed by amperometric measurement using an NO-specific electrode. In the modified Boyden chamber, L-NAME (1 mmol/L) significantly inhibited endothelial cell migration, whereas L-NAME did not affect endothelial DNA synthesis as assessed by analysis of [3H]thymidine incorporation. We then examined alteration of endothelial cell adhesion molecule expression after the inhibition of NO by L-NAME in cultured human umbilical vein endothelial cells. In both normoxic and hypoxic conditions, L-NAME (1 mmol/L) inhibited surface expression of integrin alphavbeta3, which is an important integrin facilitating endothelial cell survival and angiogenesis. However, L-NAME did not affect the expression of platelet endothelial cell adhesion molecule-1, intercellular adhesion molecule-1, vascular endothelial adhesion molecule-1, gap junction protein connexin 43, and VE-cadherin, which have been reported to potentially affect angiogenesis. In summary, inhibition of endothelial NO synthase by L-NAME attenuated endothelial cell migration but not proliferation in vitro. Furthermore, endogenous endothelium-derived NO maintains the functional expression of integrin alphavbeta3, a mediator for endothelial migration, survival, and angiogenesis. Endothelium-derived NO, thus, may play an important role in mediating angiogenesis by supporting endothelial cell migration, at least partly, via an integrin-dependent mechanism.
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PMID 
T Murohara, K Kugiyama, Y Ota, H Doi, N Ogata, M Ohgushi, H Yasue (1999)  Effects of atrial and brain natriuretic peptides on lysophosphatidylcholine-mediated endothelial dysfunction.   J Cardiovasc Pharmacol 34: 6. 870-878 Dec  
Abstract: Lysophosphatidylcholine (LPC), a major atherogenic lysophospholipid contained in oxidized low-density lipoprotein (ox-LDL), induces endothelial dysfunction. Recent studies showed that natriuretic peptides (NPs) have antiatherogenic properties by inhibiting vascular smooth-muscle cell proliferation, but their effects on endothelial cells are little known. We examined whether atrial and brain NPs (ANP and BNP) have a protecting action against LPC-induced endothelial dysfunction. LPC (10 microM) significantly inhibited thrombin (0.001-1 U/ml)-induced endothelium-dependent relaxation without affecting endothelium-independent relaxation to sodium nitroprusside in isolated porcine coronary arteries. The impaired endothelium-dependent relaxation induced by LPC was prevented by treatment with ANP or BNP (i microM). In cultured bovine aortic endothelial cells (BAECs), LPC (10 microM) significantly attenuated bradykinin (1 microM)-stimulated nitric oxide (NO) release; however, this was prevented by ANP and BNP. Because LPC-induced endothelial dysfunction has been shown to be mediated at least in part by activation of the protein kinase C (PKC)-dependent signaling pathway, we also examined the effects of ANP and BNP on LPC-induced modulation of PKC activities in BAECs. LPC (10 microM) significantly stimulated PKC activity in BAECs. However, ANP or BNP significantly inhibited LPC (10 microM)-induced PKC activation. In conclusion, ANP and BNP protected endothelial cells from LPC-induced dysfunction in both isolated coronary arteries and cultured ECs. The mechanism appears to be at least in part related to the inhibition of LPC-induced PKC activation by NPs. These new actions of ANP and BNP against lysolipid-induced endothelial cytotoxicity may partly account for antiatherogenic properties of NPs.
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1998
 
PMID 
T Murohara, J R Horowitz, M Silver, Y Tsurumi, D Chen, A Sullivan, J M Isner (1998)  Vascular endothelial growth factor/vascular permeability factor enhances vascular permeability via nitric oxide and prostacyclin.   Circulation 97: 1. 99-107 Jan  
Abstract: BACKGROUND: Vascular endothelial growth factor (VEGF), an endothelial cell mitogen that promotes angiogenesis, was initially identified as a vascular permeability factor (VPF). Abundant evidence suggests that angiogenesis is preceded and/or accompanied by enhanced microvascular permeability. The mechanism by which VEGF/VPF increases vascular permeability (VP), however, has remained enigmatic. Accordingly, we used an in vivo assay of VP (Miles assay) to study the putative mediators of VEGF/VPF-induced permeability. METHODS AND RESULTS: VEGF/VPF and positive controls (platelet-activating factor [PAF], histamine, and bradykinin) all increased vascular permeability. Prior administration of the tyrosine kinase inhibitors genistein or herbimycin A prevented VEGF/VPF-induced permeability. Placenta growth factor, which binds to Flt-1/VEGF-R1 but not Flk-1/KDR/VEGF-R2 receptor tyrosine kinase, failed to increase permeability. Other growth factors such as basic fibroblast growth factor (FGF), acidic FGF, platelet-derived growth factor-BB, transforming growth factor-beta, scatter factor, and granulocyte macrophage-colony stimulating factor (8 to 128 ng) failed to increase permeability. VEGF/VPF-induced permeability was significantly attenuated by the nitric oxide (NO) synthase inhibitors N(omega)-nitro-L-arginine (10 mg/kg) or N(omega)-nitro-L-arginine methyl ester (20 mg/kg) and the cyclooxygenase inhibitor indomethacin (5 mg/kg). The inactive enantiomer N(omega)-nitro-D-arginine methyl ester (20 mg/kg) did not inhibit VEGF/VPF-induced permeability. In vitro studies confirmed that VEGF/VPF stimulates synthesis of NO and prostaglandin metabolites in microvascular endothelial cells. Finally, NO donors and the prostacyclin analogue taprostene administered together but not alone reproduced the increase in permeability observed with VEGF/VPF. CONCLUSIONS: These results implicate NO and prostacyclin produced by the interaction of VEGF/VPF with its Flk-1/KDR/VEGF-R2 receptor as mediators of VEGF/VPF-induced vascular permeability. Moreover, this property appears unique to VEGF/VPF among angiogenic cytokines.
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PMID 
R van der Zee, T Murohara, J Passeri, M Kearney, D A Cheresh, J M Isner (1998)  Reduced intimal thickening following alpha(v)beta3 blockade is associated with smooth muscle cell apoptosis.   Cell Adhes Commun 6: 5. 371-379  
Abstract: The adhesion integrin alpha(v)beta3 is expressed by both activated endothelial cells (ECs) and smooth muscle cells (SMCs). Peptide and antibody antagonists of alpha(v)beta3 have been shown to block angiogenesis by initiating unscheduled programmed cell death of proliferating ECs. The present study was designed to determine if antagonism of alpha(v)beta3 immediately following balloon injury might similarly lead to programmed cell death among activated SMCs, and thereby inhibit intimal thickening. LM609, a monoclonal antibody antagonist of alpha(v)beta3, was administered locally and/or systemically immediately after balloon angioplasty in a rabbit model of vascular injury. Immunohistochemical studies documented that LM609, even when administered systemically, localized to sites of vascular injury. LM609 administered immediately following balloon injury of the external iliac artery markedly reduced intimal thickening at 2 and 4 wk post-injury. Apoptosis was abundant where balloon injury resulted in expression of alpha(v)beta3. At both 2 and 4 wk, re-endothelialization at the site of balloon injury was not retarded in LM609-treated rabbits versus controls. Thus, blockade of alpha(v)beta3 inhibits intimal thickening when administered immediately following balloon injury. This favorable impact on neointimal thickening is associated with apoptosis of activated SMCs expressing alpha(v)beta3. These findings may explain the reduction in restenosis observed clinically following beta3 integrin blockade.
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PMID 
T Murohara, T Asahara, M Silver, C Bauters, H Masuda, C Kalka, M Kearney, D Chen, J F Symes, M C Fishman, P L Huang, J M Isner (1998)  Nitric oxide synthase modulates angiogenesis in response to tissue ischemia.   J Clin Invest 101: 11. 2567-2578 Jun  
Abstract: We tested the hypothesis that endothelial nitric oxide synthase (eNOS) modulates angiogenesis in two animal models in which therapeutic angiogenesis has been characterized as a compensatory response to tissue ischemia. We first administered L-arginine, previously shown to augment endogenous production of NO, to normal rabbits with operatively induced hindlimb ischemia. Angiogenesis in the ischemic hindlimb was significantly improved by dietary supplementation with L-arginine, compared to placebo-treated controls; angiographically evident vascularity in the ischemic limb, hemodynamic indices of limb perfusion, capillary density, and vasomotor reactivity in the collateral vessel-dependent ischemic limb were all improved by oral L-arginine supplementation. A murine model of operatively induced hindlimb ischemia was used to investigate the impact of targeted disruption of the gene encoding for ENOS on angiogenesis. Angiogenesis in the ischemic hindlimb was significantly impaired in eNOS-/- mice versus wild-type controls evaluated by either laser Doppler flow analysis or capillary density measurement. Impaired angiogenesis in eNOS-/- mice was not improved by administration of vascular endothelial growth factor (VEGF), suggesting that eNOS acts downstream from VEGF. Thus, (a) eNOS is a downstream mediator for in vivo angiogenesis, and (b) promoting eNOS activity by L-arginine supplementation accelerates in vivo angiogenesis. These findings suggest that defective endothelial NO synthesis may limit angiogenesis in patients with endothelial dysfunction related to atherosclerosis, and that oral L-arginine supplementation constitutes a potential therapeutic strategy for accelerating angiogenesis in patients with advanced vascular obstruction.
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DOI   
PMID 
S Kamijikkoku, T Murohara, S Tayama, K Matsuyama, T Honda, M Ando, K Hayasaki (1998)  Acute myocardial infarction and increased soluble intercellular adhesion molecule-1: a marker of vascular inflammation and a risk of early restenosis?   Am Heart J 136: 2. 231-236 Aug  
Abstract: BACKGROUND: Plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) have been shown to predict activities of inflammatory disorders and malignancies. However, it is unknown whether the plasma level of sICAM-1 is increased in patients with acute myocardial infarction (AMI) with coronary intervention and whether the levels have any diagnostic or predictive values for vascular disease activity in patients with AMI. METHODS: We prospectively observed the time course of the plasma sICAM-1 levels in 20 patients with AMI whose infarct-related coronary artery was successfully recanalized by emergency balloon angioplasty. sICAM-1 was measured by enzyme-linked immunoassay. RESULTS: At admission, 48 hours, 1 week, and 2 weeks after angioplasty, sICAM-1 levels were significantly elevated in patients who had early (3 weeks) restenosis develop compared with those who did not (p < 0.05). At the other time points examined, there was a tendency of higher sICAM-1 levels in patients with than without restenosis (0.06 < p < 0.09). The relation of sICAM-1 levels and total white blood cell counts, neutrophil counts, or numbers of diseased major coronary artery branches was not statistically significant. CONCLUSIONS: A persistent increase in plasma sICAM-1 levels may indirectly implicate vascular inflammation, which could predict the risk of early coronary restenosis after emergency angioplasty in patients with AMI. Hence, measurements of sICAM-1 in patients with AMI would serve as a potentially useful predictor of the risk of early postangioplasty restenosis.
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PMID 
B Witzenbichler, T Asahara, T Murohara, M Silver, I Spyridopoulos, M Magner, N Principe, M Kearney, J S Hu, J M Isner (1998)  Vascular endothelial growth factor-C (VEGF-C/VEGF-2) promotes angiogenesis in the setting of tissue ischemia.   Am J Pathol 153: 2. 381-394 Aug  
Abstract: Recently, vascular endothelial growth factor-C (VEGF-C or VEGF-2) was described as a specific ligand for the endothelial receptor tyrosine kinases VEGFR-2 and VEGFR-3. In vivo data, limited to constitutive overexpression in transgenic mice, have been interpreted as evidence that the growth-promoting effects of VEGF-C are restricted to development of the lymphatic vasculature. The current studies were designed to test the hypothesis that constitutive expression of VEGF-C in adult animals promotes angiogenesis. In vitro, VEGF-C exhibited a dose-dependent mitogenic and chemotactic effect on endothelial cells, particularly for microvascular endothelial cells (72% and 95% potency, respectively, compared with VEGF-A/VEGF-1). VEGF-C stimulated release of nitric oxide from endothelial cells and increased vascular permeability in the Miles assay; the latter effect was attenuated by pretreatment with the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester. Both VEGFR-2 and VEGFR-3 receptors were shown to be expressed in human saphenous vein and internal mammary artery. The potential for VEGF-C to promote angiogenesis in vivo was then tested in a rabbit ischemic hindlimb model. Ten days after ligation of the external iliac artery, VEGF-C was administered as naked plasmid DNA (pcVEGF-C; 500 microg) from the polymer coating of an angioplasty balloon (n = 8 each) or as recombinant human protein (rhVEGF-C; 500 microg) by direct intra-arterial infusion. Physiological and anatomical assessments of angiogenesis 30 days later showed evidence of therapeutic angiogenesis for both pcVEGF-C and rhVEGF-C. Hindlimb blood pressure ratio (ischemic/normal) after pcVEGF-C increased to 0.83 +/- 0.03 after pcVEGF-C versus 0.59 +/- 0.04 (P < 0.005) in pGSVLacZ controls and to 0.76 +/- 0.04 after rhVEGF-C versus 0.58 +/- 0.03 (P < 0.01) in control rabbits receiving rabbit serum albumin. Doppler-derived iliac flow reserve was 2.7 +/- 0.1 versus 2.0 +/- 0.2 (P < 0.05) for pcVEGF-C versus LacZ controls and 2.9 +/- 0.3 versus 2.1 +/- 0.2 (P < 0.05) for rhVEGF-C versus albumin controls. Neovascularity was documented by angiography in vivo (angiographic scores: 0.85 +/- 0.05 versus 0.51 +/- 0.02 (P < 0.001) for plasmid DNA and 0.74 +/- 0.08 versus 0.53 +/- 0.03 (P < 0.05) for protein), and capillary density (per mm2) was measured at necropsy (252 +/- 12 versus 183 +/- 10 (P < 0.005) for plasmid DNA and 229 +/- 20 versus 164 +/- 20 (P < 0.05) for protein). In contrast to the results of gene targeting experiments, constitutive expression of VEGF-C in adult animals promotes angiogenesis in the setting of limb ischemia. VEGF-C and its receptors thus constitute an apparently redundant pathway for postnatal angiogenesis and may represent an alternative to VEGF-A for strategies of therapeutic angiogenesis in patients with limb and/or myocardial ischemia.
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PMID 
A Katoh, H Ikeda, T Murohara, N Haramaki, H Ito, T Imaizumi (1998)  Platelet-derived 12-hydroxyeicosatetraenoic acid plays an important role in mediating canine coronary thrombosis by regulating platelet glycoprotein IIb/IIIa activation.   Circulation 98: 25. 2891-2898 Dec  
Abstract: BACKGROUND: In the thrombotic process of acute coronary syndromes, the pathophysiological role of thromboxane A2 via cyclooxygenase is well established; however, the role of 12-HETE via 12-lipoxygenase is little known. Therefore, we used OPC-29030, a novel specific inhibitor of 12-HETE synthesis, to test whether platelet-derived 12-HETE is involved in mediating cyclic flow variations (CFVs) and platelet aggregation in stenosed and endothelium-injured canine coronary arteries. METHODS AND RESULTS: After developing CFVs, dogs received a vehicle or OPC-29030 intravenously. Plasma and intraplatelet 12-HETE levels increased after CFVs. OPC-29030 but not vehicle reduced CFVs, which was associated with decreases in plasma and intraplatelet 12-HETE levels. Cessation of OPC-29030 restored CFVs in association with increases in plasma and intraplatelet 12-HETE levels. ADP and U46619 induced ex vivo platelet 12-HETE production and aggregation. After OPC-29030 administration, the ADP- and U46619-induced increases in ex vivo platelet 12-HETE production and aggregation were inhibited significantly. Platelet aggregation was linearly correlated with platelet 12-HETE production. OPC-29030 suppressed activation of human platelet glycoprotein IIb/IIIa. CONCLUSIONS: OPC-29030 reduced intraplatelet 12-HETE levels, resulting in the inhibition of coronary thrombosis in vivo in dogs. OPC-29030 inhibited human platelet glycoprotein IIb/IIIa activation in vitro. Thus, platelet-derived 12-HETE may play an important role in mediating thrombotic process.
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1997
 
PMID 
R van der Zee, T Murohara, Z Luo, F Zollmann, J Passeri, C Lekutat, J M Isner (1997)  Vascular endothelial growth factor/vascular permeability factor augments nitric oxide release from quiescent rabbit and human vascular endothelium.   Circulation 95: 4. 1030-1037 Feb  
Abstract: BACKGROUND: Vascular endothelial growth factor (VEGF)/ vascular permeability factor (VPF) is an endothelial cell (EC) mitogen. This feature is considered central to the documented role of VEGF/VPF in promoting angiogenesis. More recent evidence suggests that VEGF/VPF may also serve a "maintenance" function, modulating various aspects of EC biology. In the present study, we sought to determine the extent to which VEGF/VPF may stimulate the release of NO from normal ECs. METHODS AND RESULTS: VEGF/VPF produced a dose-dependent rise in NO concentration ([NO]) from vascular segments of rabbit thoracic aorta, pulmonary artery, and inferior vena cava. In comparison to stimulation with acetylcholine, the onset of increased [NO] after administration of VEGF/VPF was slower, reaching a maximum value after 8 minutes. Preincubation of the aortic segments with L-arginine raised by twofold both baseline [NO] and [NO] stimulated by addition of 2.5 micrograms/mL VEGF/VPF. Removal of CaCl2 from the Krebs solution, disruption of the endothelium, and administration of NG-monomethyl-L-arginine abrogated the stimulatory effect of 10 micrograms/mL VEGF/VPF. Similar findings were documented with an NO-specific polarographic electrode to measure NO released from cultured human umbilical vein ECs. CONCLUSIONS: VEGF/VPF stimulates production of NO from rabbit and human ECs. This finding (1) constitutes inferential evidence for the presence of functional VEGF/VPF receptors on quiescent endothelium of the adult rabbit as well as human ECs and (2) supports the notion that putative maintenance functions of VEGF/VPF may include regulation of baseline synthesis and/or release of EC NO.
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PMID 
T Asahara, T Murohara, A Sullivan, M Silver, R van der Zee, T Li, B Witzenbichler, G Schatteman, J M Isner (1997)  Isolation of putative progenitor endothelial cells for angiogenesis.   Science 275: 5302. 964-967 Feb  
Abstract: Putative endothelial cell (EC) progenitors or angioblasts were isolated from human peripheral blood by magnetic bead selection on the basis of cell surface antigen expression. In vitro, these cells differentiated into ECs. In animal models of ischemia, heterologous, homologous, and autologous EC progenitors incorporated into sites of active angiogenesis. These findings suggest that EC progenitors may be useful for augmenting collateral vessel growth to ischemic tissues (therapeutic angiogenesis) and for delivering anti- or pro-angiogenic agents, respectively, to sites of pathologic or utilitarian angiogenesis.
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PMID 
T Couffinhal, M Kearney, B Witzenbichler, D Chen, T Murohara, D W Losordo, J Symes, J M Isner (1997)  Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) in normal and atherosclerotic human arteries.   Am J Pathol 150: 5. 1673-1685 May  
Abstract: Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) is an endothelial-cell-specific mitogen; as such, its role in angiogenesis has been studied extensively. VEGF/VPF may also serve as a local, endogenous regulator of large-vessel endothelial cell integrity. Surprisingly, however, VEGF/VPF expression in normal and/or atherosclerotic vessels has not been previously characterized. Accordingly, we studied normal human arteries and veins as well as atherosclerotic and restenotic human coronary arteries for evidence of VEGF/VPF expression. VEGF/VPF was detected immunohistochemically in sections of normal human aorta, mammary artery, and saphenous vein. Moreover, VEGF/ VPF expression was identified in 32 (97%) of 33 pathological coronary arterial specimens; the extent of VEGF/VPF staining was graded as moderate to strong in 21 of the 32 (66%) positive specimens. VEGF/VPF double immunostaining and in situ hybridization demonstrated that smooth muscle cells constitute the principal cellular source of VEGF/VPF. VEGF/VPF immunostaining among primary atherosclerotic lesions localized predominantly to the extracellular matrix. In restenotic specimens, VEGF/VPF immunostaining was more prominently cellular, particularly among proliferating smooth muscle cells. Although VEGF/VPF expression was observed in areas of macrophage infiltration, double immunostaining failed to localize VEGF/VPF to macrophages in these foci; instead, double immunostaining clearly identified CD45RO-positive cells as responsible for VEGF/VPF expression in such areas. No correlation could be demonstrated between VEGF/VPF immunostaining and extent of vasa vasorum. These findings thus establish that postnatal VEGF/VPF expression is a feature of normal human arteries and veins and is often extensively expressed in arteries narrowed by atherosclerotic plaque. VEGF/VPF expression in the wall and/or plaque of medium to large vessels suggests a role for VEGF/VPF other than promoting angiogenesis. This role may involve maintenance and repair of luminal endothelium.
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PMID 
Y Tsurumi, T Murohara, K Krasinski, D Chen, B Witzenbichler, M Kearney, T Couffinhal, J M Isner (1997)  Reciprocal relation between VEGF and NO in the regulation of endothelial integrity.   Nat Med 3: 8. 879-886 Aug  
Abstract: Balloon angioplasty disrupts the protective endothelial lining of the arterial wall, rendering arteries susceptible to thrombosis and intimal thickening. We show here that vascular endothelial growth factor (VEGF), an endothelial cell mitogen, is upregulated in medial smooth muscle cells of the arterial wall in response to balloon injury. Both protein kinase C (PKC) and tyrosine kinase pp60src mediate augmented VEGF expression. In contrast, nitric oxide (NO) donors inhibit PKC-induced VEGF upregulation by interfering with binding of the transcription factor activator protein-1 (AP-1) to the VEGF promoter. Inhibition of VEGF promoter activation suggests that NO secreted by a restored endothelium functions as the negative feedback mechanism that downregulates VEGF expression to basal levels. Administration of a neutralizing VEGF antibody impaired reendothelialization following balloon injury performed in vivo. These findings establish a reciprocal relation between VEGF and NO in the endogenous regulation of endothelial integrity following arterial injury.
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PMID 
R Scalia, T Murohara, B Campbell, A Kaji, A M Lefer (1997)  Lysophosphatidylcholine stimulates leukocyte rolling and adherence in rat mesenteric microvasculature.   Am J Physiol 272: 6 Pt 2. H2584-H2590 Jun  
Abstract: Synthetic exogenous lysophosphatidylcholine (LPC) was used to induce leukocyte-endothelial cell interaction, utilizing intravital microscopy in the rat mesenteric microvasculature. Superfusion of the rat mesentery with 10 microM LPC significantly and time dependently increased leukocyte rolling and adherence compared with control rats. Moreover, LPC superfusion did not alter systemic blood pressure or mesenteric venular shear rate. Administration of either an anti-P-selectin monoclonal antibody (PB1.3 at 1 mg/kg i.v.) or a nitric oxide (NO) donor (CAS-1609, 10 microM superfusion) markedly attenuated LPC-induced leukocyte rolling and adherence (P < 0.01 from LPC alone). Immunohistochemical localization of P-selectin and intercellular adhesion molecule-1 (ICAM-1) expression on mesenteric venules was significantly increased after exposure to LPC compared with mesenteries superfused with phosphatidylcholine (P < 0.001). Flow cytometric analysis indicated that 10 microM LPC significantly (P < 0.05) increased P-selectin fluorescence on rat platelets. Furthermore, direct measurement of NO release from rat aortic vascular endothelium was significantly (P < 0.05) inhibited by 10 microM LPC. Thus LPC induces in vivo leukocyte rolling and adherence in the mesenteric rat microvasculature by increasing the surface expression of P-selectin and ICAM-1. Because inhibition of endothelial NO release promotes P-selectin expression, LPC-induced rolling and adherence may be mediated via reduced NO release.
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PMID 
Z Luo, M Diaco, T Murohara, N Ferrara, J M Isner, J F Symes (1997)  Vascular endothelial growth factor attenuates myocardial ischemia-reperfusion injury.   Ann Thorac Surg 64: 4. 993-998 Oct  
Abstract: BACKGROUND: Hypoxic endothelial cell activation plays a key role in the myocardial dysfunction resulting from ischemia-reperfusion injury. Recent evidence suggests that vascular endothelial growth factor (VEGF) may, in addition to promoting angiogenesis, modulate various aspects of endothelial function and repair. We examined whether administration of VEGF in the cardioplegic solution might have a beneficial effect on myocardial ischemia-reperfusion injury in an isolated rat heart model. METHODS: Hearts from Sprague-Dawley rats were perfused with Krebs-Henseleit solution in a modified Langendorff apparatus. Percent recovery of cardiac output, coronary flow, stroke work, and percent increase in coronary vascular resistance were measured after 2 hours of global ischemia and 40 minutes of reperfusion. Coronary effluent was collected after ischemia and reperfusion for measurement of creatine kinase. RESULTS: Hearts receiving cardioplegia solution containing 125 microg VEGF showed significantly improved recovery of cardiac output, coronary flow, and stroke work, and significantly reduced coronary vascular resistance compared with hearts receiving hyperkalemic cardioplegia only (p < 0.05). Coadministration of a nitric oxide synthase inhibitor attenuated the VEGF-induced cardiprotective effects. Hearts treated with VEGF released significantly less creatine kinase compared with control hearts. CONCLUSIONS: Addition of VEGF to hyperkalemic cardioplegia protects against myocardial ischemia-reperfusion injury in the isolated rat heart.
Notes:
1996
 
PMID 
T Murohara, M Buerke, A M Lefer (1996)  Cardioprotective actions of oligotide, a single stranded polydeoxyribonucleotide complex, in myocardial ischaemia and reperfusion injury.   Br J Pharmacol 117: 6. 1000-1008 Mar  
Abstract: 1. The efficacy of oligotide, a single stranded polydeoxyribonucleotide complex, was examined in a feline model of myocardial ischaemia (MI: 90 min) and reperfusion (R: 270 min). Oligotide (15 mg kg-1 bolus) was administered intravenously 80 min after occlusion of the left anterior descending (LAD) coronary artery (i.e., 10 min prior to R) and continued for an additional 280 min (10 mg kg-1 h-1 infusion). 2. Oligotide-treated cats showed significantly smaller myocardial necroses and lower cardiac myeloperoxidase activities (significantly lower neutrophil infiltration) in the necrotic zone as compared to MI+R cats receiving only vehicle. 3. LAD coronary arteries isolated from MI+R cats exhibited a significant endothelial dysfunction (i.e., reduced endothelium-dependent relaxation), and significantly increased adherence of polymorphonuclear neutrophils (PMNs) ex vivo. However, oligotide significantly preserved endothelial function and attenuated PMN adherence in ischaemic LAD coronary arteries. 4. Oligotide attenuated P-selectin expression on thrombin-stimulated platelets as well as PMN adherence to thrombin-stimulated coronary endothelium. Immunohistochemical examination in vivo revealed that oligotide treatment also significantly inhibited coronary endothelial P-selectin expression after 90 min MI and 20 min R. 5. Oligotide exerted a significant cardioprotection in MI+R injury. The mechanism appears to be related to attenuation of PMN-endothelial interaction and eventual infiltration into the ischaemic myocardium.
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PMID 
J A Delyani, T Murohara, A M Lefer (1996)  Novel recombinant serpin, LEX-032, attenuates myocardial reperfusion injury in cats.   Am J Physiol 270: 3 Pt 2. H881-H887 Mar  
Abstract: We studied the potential cardioprotective effects of the novel recombinant serine protease inhibitor (serpin), LEX-032, which inhibits the serine proteases elastase and cathepsin G. LEX-032 is a recombinant construct of human alpha 1-antichymotrypsin in which six amino acid residues were replaced around the active center with those of human alpha 1-protease inhibitor. Cats were subjected to 90 min of left anterior descending coronary artery (LAD) occlusion and 270 min of reperfusion (MI/R). Either LEX-032 or its vehicle (i.e., phosphate-buffered saline) was administered intravenously 10 min before reperfusion. Control cats were subjected to sham MI/R. Cats treated with LEX-032 demonstrated a marked reduction in cardiac necrosis after MI/R compared with cats receiving only vehicle (10 +/- 3 vs. 31 +/- 3%, P < 0.01). In addition, relaxation of LAD rings to the endothelium-dependent dilators (e.g., acetylcholine and A23187) was greater in the LEX-032-treated group than in cats receiving vehicle (72 +/- 5 vs. 52 +/- 7%, P < 0.05, and 74 +/- 8 vs. 50 +/- 8%, P < 0.05, respectively), indicating that endothelial function was preserved by LEX-032. Moreover, LEX-032 administration resulted in a marked reduction of polymorphonuclear leukocyte (PMN) adherence to ex vivo coronary vascular endothelium compared with vehicle (33 +/- 4 vs. 86 +/- 7 PMNs/mm2, P < 0.01). These data indicate that LEX-032 is a significant cardioprotective agent exerting its protective effect by inhibition of PMN-mediated cellular injury, and this agent represents a novel means of attenuating PMN-mediated reperfusion injury.
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PMID 
R Scalia, T Murohara, J A Delyani, T O Nossuli, A M Lefer (1996)  Myocardial protection by N,N,N-trimethylsphingosine in ischemia reperfusion injury is mediated by inhibition of P-selectin.   J Leukoc Biol 59: 3. 317-324 Mar  
Abstract: Polymorphonuclear leukocytes (PMNs) play an important role in myocardial ischemia/reperfusion (MI/R) injury. We examined the cardioprotective effects of N,N,N-trimethylsphingosine (TMS) in a murine model of MI (20 min) and R (24 h) injury in vivo, focusing on leukocyte-endothelial interactions. TMS is a synthetic N-methylated sphingosine derivative that has protein kinase C inhibitory activity and has been shown to prevent leukocyte activation. TMS (18 microgram/kg), administered intravenously 1 min prior to reperfusion, significantly attenuated myocardial necrotic injury assessed by myocardial creatine kinase loss compared with MI/R rats receiving only vehicle (P<0.001). Cardiac myeloperoxidase activity, an index of PMN accumulation in the ischemic myocardium, was also significantly attenuated by TMS compared with rats receiving vehicle (P<0.001). We further examined whether TMS can attenuate leukocyte-endothelial interaction by intravital microscopy. TMS significantly attenuated NG-nitro-L-arginine-methyl ester (L-NAME)-stimulated PMN rolling and adherence to the rat microvascular endothelium. This action of TMS appears to be mediated by reduction of P-selectin expression because immunohistochemical analysis demonstrated that TMS significantly attenuated endothelial P-selectin expression in the L-NAME-superfused rat mesenteric microvasculature. Similarly, TMS markedly attenuated rapid P-selectin expression in rat platelets stimulated with either thrombin or L-NAME assessed by flow cytometry. In conclusion, TMS seems to be an effective cardioprotective agent by inhibiting early leukocyte-endothelial interaction, thus preventing leukocyte accumulation in the ischemic reperfused myocardium.
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PMID 
T Murohara, J A Delyani, S M Albelda, A M Lefer (1996)  Blockade of platelet endothelial cell adhesion molecule-1 protects against myocardial ischemia and reperfusion injury in cats.   J Immunol 156: 9. 3550-3557 May  
Abstract: Polymorphonuclear leukocytes have been shown to play an important role in myocardial ischemia (MI) and reperfusion (R) injury. Since blockade of platelet-endothelial cell adhesion molecules (PECAM-1) inhibits neutrophil transmigration in vitro and in vivo, the effects of a polygonal Ab directed against PECAM-1 were examined in a feline model of Ml/R. We established cross-reactivity of our anti-human PECAM-1 Ab to cat coronary vasculature and neutrophils by immunohistochemistry and flow cytometry. The anti-PECAM-1 Ab markedly blocked leukocyte transmigration into the peritoneal cavity of cats after glycogen-induced peritonitis. Then, anti-PECAM-1 Ab (1 mg/kg) was tested to determine whether it attenuates MI/R injury in a well characterized feline model of Ml and R. Anti-PECAM-1 Ab administered 10 min before R significantly inhibited the myocardial necrosis seen 4.5 h post-R compared with that in MI/R cats treated with control isotype rabbit IgG (12 +/- 2 vs 29 +/- 4% of area at risk; p less than 0.01) and significantly attenuated the rise in plasma creatine kinase activity (p less than 0.05). The Ab did not prevent increases in cardiac myeloperoxidase activity within the affected regions and did not significantly inhibit autologous neutrophil adhesion to coronary endothelium after stimulation of either neutrophils (by leukotriene B4) or coronary endothelium (by thrombin) in vitro. These results indicate that in vivo blockade of PECAM-1 significantly attenuates MI/R injury, presumably by inhibiting transendothelial migration of neutrophils.
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PMID 
T Murohara, K Kugiyama, H Yasue (1996)  Interactions of nitrovasodilators, atrial natriuretic peptide and endothelium-derived nitric oxide.   J Vasc Res 33: 1. 78-85 Jan/Feb  
Abstract: Nitroglycerin (NTG), endothelium-derived relaxing factor (EDRF) and atrial natriuretic peptide (ANP) dilate vessels by a common pathway (cyclic guanosine monophosphate- dependent mechanism). Thus, these vasodilators may potentially influence the vasodilator properties of each other. We examined whether tolerance to NTG influences vasorelaxation to ANP, EDRF and other nitrovasodilators, isosorbide dinitrate (ISDN) and sodium nitroprusside (SNP). Concentration-response curves for various vasodilators during stable contraction to PGF2alpha were examined before and after the induction of NTG tolerance. Rings exposed to NTG (100 microM) for 60 min showed marked impairment of vasorelaxation to NTG itself. This NTG tolerance significantly attenuated vasorelaxation to either ISDN, SNP or EDRF stimulated by bradykinin. In contrast, the NTG tolerance did not alter vasorelaxation to either ANP or isoproterenol. The attenuated responses to NTG, ISDN, SNP and bradykinin recovered in a time-dependent manner during the subsequent washout period, suggesting this inhibition is reversible. The denudation of the endothelium significantly sensitized relaxation to NTG but did not change relaxation to ANP. These results suggest that (1) vasorelaxations to nitrovasodilators and EDRF are significantly attenuated by NTG tolerance and (2) ANP-induced vasorelaxation is not affected by exposure to either exogenous nitrovasodilator or endogenous endothelium-derived nitric oxide. ANP may be a potentially beneficial vasodilator in arteries which have developed tolerance to nitrovasodilators.
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DOI   
PMID 
R Scalia, T W Gauthier, T Murohara, A M Lefer (1996)  Oligotide attenuates leukocyte-endothelial cell interaction via P-selectin in the rat mesenteric vascular bed.   Eur J Pharmacol 296: 2. 181-187 Jan  
Abstract: A novel single stranded polydeoxyribonucleotide (oligotide) was studied for its ability to modulate leukocyte-endothelial cell interaction, by means of intravital microscopy in the rat mesenteric microvasculature. Superfusion of the rat mesentery with 50 microM NG-nitro-L-arginine methyl ester (L-NAME), caused a significant, time-dependent increase in leukocyte rolling and adherence compared to control rats superfused with Krebs-Henseleit solution. However, oligotide (15 mg/kg i.v.) consistently reduced the L-NAME-induced leukocyte rolling (62 +/- 14 vs. 23 +/- 3 cells/min; P < 0.02) and adherence (11 +/- 2 vs. 4 +/- 1 cells/100 microns length of venule P < 0.01), without altering systemic blood pressure or mesenteric venular shear rate. Moreover, immunohistochemical localization of P-selectin expression on mesenteric venules was significantly increased (P < 0.01) after exposure to L-NAME, which was significantly attenuated by oligotide (P < 0.05). Similar results were also obtained by flow cytometric analysis performed on rat platelets. Stimulation of rat platelets with L-NAME significantly (P < 0.05) increased the fluorescence intensity of P-selectin, while the concomitant treatment of isolated rat platelets with L-NAME plus oligotide significantly (P < 0.005) attenuated P-selectin fluorescence intensity. Our data demonstrate that in vivo administration of oligotide can reduce leukocyte rolling and adherence in the mesenteric rat microvasculature by attenuating P-selectin expression, and confirming the key role of nitric oxide as an important regulator of leukocyte-endothelial cell interaction.
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PMID 
J P Guo, T Murohara, M Buerke, R Scalia, A M Lefer (1996)  Direct measurement of nitric oxide release from vascular endothelial cells.   J Appl Physiol 81: 2. 774-779 Aug  
Abstract: A nitric oxide (NO)-selective electrode was used to directly measure NO release from isolated rat aortic endothelium and cultured rat aortic endothelial cells (RAECs). Basal release of NO was significantly attenuated by a NO synthase inhibitor NG-nitro-L-arginine methyl ester (1 mM) to 42 +/- 14 pmol/1 x 10(5) cells (P < 0.01). The basal release of NO was also significantly inhibited by a calmodulin antagonist W-7 at 15 microM (P < 0.01). L-Arginine (1 mM), significantly stimulated NO release (P < 0.05 vs. control basal release). Stimulation of cultured RAECs with two endothelium-dependent vasodilators, acetylcholine (100 nM) and A-23187 (1 microM), significantly increased NO release [574 +/- 112 pmol/1 x 10(5) cells (n = 5) and 658 +/- 119 pmol/1 x 10(5) cells (n = 5) in acetylcholine- and A-23187-stimulated RAECs, respectively]. Basal release of NO was also detectable in isolated rat aortic rings with intact endothelium. NO release was significantly attenuated by NG-nitro-L-arginine methyl ester and augmented by human superoxide dismutase. These data indicate the physiological usefulness of the amperometric measurement of NO employing a NO-specific electrode in biological systems.
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PMID 
T Murohara, R Scalia, A M Lefer (1996)  Lysophosphatidylcholine promotes P-selectin expression in platelets and endothelial cells. Possible involvement of protein kinase C activation and its inhibition by nitric oxide donors.   Circ Res 78: 5. 780-789 May  
Abstract: Lysophosphatidylcholine (LysoPC), an atherogenic lysophospholipid contained in oxidized low-density lipoprotein (LDL), has been shown to stimulate protein kinase C (PKC). Since PKC activators are suggested to elicit rapid P-selectin expression in platelets and endothelial cells, we examined whether LysoPc promotes P-selectin expression in platelets and P-selectin-mediated leukocyte adherence to endothelial cells via a mechanism involving PKC activation. LysoPc, but not phosphatidylcholine (PC), which is a major phospholipid component in native LDL, significantly upregulated P-selectin on cat platelets by flow cytometric analysis. This P-selectin upregulation by LysoPC was significantly attenuated by two PKC inhibitors, 7-hydroxystaurosporine (UCN-01) and N,N,N-trimethylsphingosine, and by two NO donors, CAS1609 and sodium nitroprusside. Submicellar concentrations of LysoPc significantly activated PKC in platelets, and this was inhibited by either UCN-01 or CAS1609. LysoPC, but not PC, significantly increased adherence of autologous cat polymorphonuclear leukocytes to coronary vascular endothelium, which was also markedly attenuated by UCN-01 and by CAS1609. LysoPC induced P-selectin expression on the surface of cat coronary vascular endothelium as assessed by immunohistochemical analysis. These results suggest that LysoPC, an atherogenic lysophospholipid contained in oxidized LDL, rapidly induces P-selectin expression in both platelets and endothelial cells at least partially via PKC activation. Furthermore, NO-generating agents may inhibit P-selectin upregulation by LysoPC. Since P-selectin may play an important role in initiating atherosclerosis, our data provide further insight into the mechanism of early stages of atherogenesis and of NO-mediated inhibition of atherosclerosis.
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PMID 
T Murohara, K Kugiyama, M Ohgushi, S Sugiyama, Y Ohta, H Yasue (1996)  Effects of sphingomyelinase and sphingosine on arterial vasomotor regulation.   J Lipid Res 37: 7. 1601-1608 Jul  
Abstract: The sphingomyelin pathway is an important signal transduction system regulating various cellular functions. However, little is known about the effect of sphingomyelin metabolites on vasomotor function. We examined the vascular effects of sphingomyelin, sphingosine, and sphingomyelinase (SPMase) in vitro. In pig coronary rings precontracted with prostaglandin F2 alpha, sphingosine and SPMase evoked initial contraction and subsequent gradual relaxation; however, sphingomyelin did not influence the tone. The initial contractions in response to either SPMase (40 microU/ml to 0.4 U/ml) or sphingosine (0.5-10 microM) treatment were abolished in rings denuded of endothelium. This initial contraction in response to sphingosine treatment was significantly attenuated by a cyclo-oxygenase inhibitor indomethacin, but not altered by either a nitric oxide synthase inhibitor, N omega-monomethyl-L-arginine (L-NMMA), a protein kinase C (PKC) inhibitor staurosporine, or superoxide dismutase (SOD, 100 U/ml). Incubation of coronary rings with sphingosine (10 microM) or SPMase (0.4 U/ml) for 120 min significantly attenuated subsequent endothelium-dependent relaxation in response to thrombin and A23187, but did not affect endothelium-independent relaxation in response to sodium nitroprusside. In contrast, sphingomyelin (10 microM) did not alter the endothelium-dependent relaxation. In conclusion, in the sphingomyelin pathway, sphingosine induces vasoconstriction in coronary arteries that seems to be mediated by the release of cyclooxygenase-sensitive vasoconstrictor prostanoids from the endothelium. Sphingosine also induced endothelial dysfunction characterized by impaired endothelium-dependent relaxation. Thus, the sphingomyelin pathway may be an important regulator of vascular function.
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PMID 
T Murohara, A M Lefer (1996)  Autocrine effects of endothelin-1 on leukocyte-endothelial interaction: stimulation of endothelin B receptor subtype reduces endothelial adhesiveness via a nitric oxide-dependent mechanism.   Blood 88: 10. 3894-3900 Nov  
Abstract: The effects of endothelin-1 (ET-1) on P-selectin-mediated leukocyte endothelial interaction were examined in vitro. Adherence of autologous polymorphonuclear leukocytes (PMNs) to the endothelium was markedly enhanced by endothelial stimulation with either (2 U/mL) thrombin, (1 mumol/L) histamine, or (100 nmol/L) phorbol myristate acetate (PMA). In contrast, ET-1 alone (10 and 100 nmol/L) only slightly increased the number of adhering PMNs. The increased PMN adherence to thrombin- or histamine-stimulated endothelium, which was blocked by an anti-P-selectin monoclonal antibody, was also significantly attenuated by preincubation of coronary segments with (100 nmol/L) ET-1. We further investigated the mechanism of this anti-adherence action of ET-1 on thrombin-stimulated endothelial adhesiveness. Preincubation of coronary segments with a selective ETA receptor antagonist, BQ485 (1 mumol/L), had no effect on ET-1 inhibition of thrombin-induced PMN adherence. In contrast, preincubation with a selective ETB receptor antagonist, BQ788 (1 mumol/L) significantly reversed ET-1 inhibition of thrombin-induced PMN adherence, whereas the selective ETB receptor agonist BQ-3020 mimicked the inhibitory action of ET-1 on thrombin-induced PMN adherence. Furthermore, (100 mumol/L) N omega-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase (NOS) inhibitor, significantly attenuated ET-1 inhibition of thrombin-stimulated PMN adherence. These results suggest that ET-1 may inhibit P-selectin-mediated leukocyte-endothelial interaction via ETB receptor stimulation and subsequent endothelial NO formation. This autocrine effect of ET-1 may be involved in pathophysiologic states such as early atherogenesis by preventing leukocyte-endothelial interaction in constricted blood vessels.
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DOI   
PMID 
J A Delyani, T Murohara, T O Nossuli, A M Lefer (1996)  Protection from myocardial reperfusion injury by acute administration of 17 beta-estradiol.   J Mol Cell Cardiol 28: 5. 1001-1008 May  
Abstract: Although several studies have demonstrated that chronic exposure to estrogen appears to be cardioprotective, acute circulatory effects of estrogen are largely unknown. Therefore, we studied the effects of acute administration of 17 beta-estradiol in myocardial ischemia/reperfusion. Cats were subjected to 90 min of left anterior descending coronary artery (LAD) occlusion and 270 min of reperfusion (MI/R). Either the estrogenic steroid, 17 beta-estradiol or its non-estrogenic isomer, 17 alpha-estradiol was administered (i.v.) 30 min prior to reperfusion at 1 microgram/kg bolus followed by a constant infusion lasting the remaining duration of the protocol at 1 microgram/kg/h. Control cats were subjected to sham MI/R. Cats treated with 17 beta-estradiol demonstrated a marked reduction in cardiac necrosis following MI/R compared to cats receiving 17 alpha-estradiol or phosphate buffered saline (17 +/- 2% v 33 +/- 1% or 34 +/- 4% area of necrosis indexed to the area-at-risk, P < 0.01). In addition, cats receiving 17 beta-estradiol exhibited reduced myocardial PMN infiltration in necrotic tissue as compared to 17 alpha-estradiol treated cats. Moreover, 17 beta-estradiol administration attenuated neutrophil adherence to ex vivo coronary vascular endothelium compared to the two controls (44 +/- 8 PMNs/mm2 v 79 +/- 7 PMNs/mm2 or 86 +/- 7 PMNs/mm2 P < 0.01). These data indicate that 17 beta-estradiol protects against myocardial ischemia/reperfusion, in part, by attenuating PMN infiltration and subsequent injury due to PMN mediator release.
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PMID 
T Murohara, S Tayama, T Tabuchi, H Sumida, T Honda, K Hayasaki, H Yasue (1996)  Effects of angiotensin-converting enzyme inhibitor alacepril in patients with stable effort angina during chronic isosorbide dinitrate treatment.   Am J Cardiol 77: 14. 1159-1163 Jun  
Abstract: Nitrate tolerance has been reported to be reversed by certain types of angiotensin-converting enzyme (ACE) inhibitors. We examined whether alacepril, a new long-acting oral ACE inhibitor, has beneficial effects against exercise-induced angina in patients with stable effort angina after substantial isosorbide dinitrate (ISDN) treatment. Thirteen men with stable effort angina were treated with oral ISDN (80 mg/d) for >3 weeks. After this period, efficacy of single oral administration of either alacepril (50 mg) or its placebo on exercise-induced angina and electrocardiographic changes was examined by treadmill exercise test in a double-blind crossover design. Alacepril significantly improved the exercise duration by 9.1% (p=0.03), the time to 1 mm ST-segment depression by 19% (p<0.01), and the maximal ST-segment depression by 33% (p=0.015) compared with placebo. Alacepril did not significantly alter the rate-pressure product, a marker of myocardial oxygen demand, during exercise test compared with placebo. Plasma renin activity was significantly increased (p<0.05) after administration of alacepril, indicating that alacepril significantly blocked ACE activity in our patients. In conclusion, a single oral administration of the ACE inhibitor alacepril (50mg) elicited beneficial effects against exercise-induced myocardial ischemia in patients with stable effort angina during chronic nitrate treatment. These effects may be mediated by increased coronary blood flow.
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1995
 
PMID 
T Murohara, J P Guo, A M Lefer (1995)  Cardioprotection by a novel recombinant serine protease inhibitor in myocardial ischemia and reperfusion injury.   J Pharmacol Exp Ther 274: 3. 1246-1253 Sep  
Abstract: Polymorphonuclear neutrophils (PMN) play an important role in myocardial ischemia/reperfusion (MI/R) injury; however, the role of neutrophilic proteases is less understood. The effects of a novel serine protease inhibitor (serpin), LEX032, were investigated in a murine model of MI (20 min) and R (24 hr) injury in vivo. LEX032 is a recombinant human alpha 1-antichymotrypsin in which six amino acid residues were replaced around the active center with those of alpha-1 protease inhibitor. LEX032 has the ability to inhibit both neutrophil elastase and cathepsin G, two major neutral serine proteases in neutrophils, as well as superoxide generation. LEX032 (25 or 50 mg/kg) administered i.v. 1 min before reperfusion significantly attenuated myocardial necrotic injury evaluated by cardiac creatine kinase loss compared to MI/R rats receiving only vehicle (P < .001). Moreover, cardiac myeloperoxidase activity, an index of PMN accumulation, in the ischemic myocardium was significantly attenuated by LEX032 as compared with rats receiving vehicle (P < .001). LEX032 also moderately attenuated leukotriene B4-stimulated PMN adherence to rat superior mesenteric artery endothelium and markedly diminished superoxide radical release from LTB4-stimulated PMN in vitro. In a glycogen-induced rat peritonitis model, LEX032 (50 mg/kg) significantly attenuated PMN transmigration into the peritoneal cavity in vivo. In conclusion, the recombinant serine protease inhibitor, LEX032, appears to be an effective agent for attenuating MI/R injury by inhibiting neutrophil-accumulation into the ischemic-reperfused myocardium and by inactivating cytotoxic metabolites (proteases and superoxide radical) released from neutrophils.
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PMID 
M Buerke, T Murohara, C Skurk, C Nuss, K Tomaselli, A M Lefer (1995)  Cardioprotective effect of insulin-like growth factor I in myocardial ischemia followed by reperfusion.   Proc Natl Acad Sci U S A 92: 17. 8031-8035 Aug  
Abstract: In the present study, the cardioprotective effects of insulin-like growth factor I (IGF-I) were examined in a murine model of myocardial ischemia reperfusion (i.e., 20 min + 24 hr). IGF-I (1-10 micrograms per rat) administered 1 hr prior to ischemia significantly attenuated myocardial injury (i.e., creatine kinase loss) compared to vehicle (P < 0.001). In addition, cardiac myeloperoxidase activity, an index of neutrophil accumulation, in the ischemic area was significantly attenuated by IGF-I (P < 0.001). This protective effect of IGF-I was not observed with des-(1-3)-IGF-I. Immunohistochemical analysis of ischemic-reperfused myocardial tissue demonstrated markedly increased DNA fragmentation due to programmed cell death (i.e., apoptosis) compared to nonischemic myocardium. Furthermore, IGF-I significantly attenuated the incidence of myocyte apoptosis after myocardial ischemia and reperfusion. Therefore, IGF-I appears to be an effective agent for preserving ischemic myocardium from reperfusion injury and protects via two different mechanisms--inhibition of polymorphonuclear leukocyte-induced cardiac necrosis and inhibition of reperfusion-induced apoptosis of cardiac myocytes.
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PMID 
A M Lefer, T Murohara (1995)  Comparative pharmacology of nitric oxide and nitric oxide generators on cardiac contractility in mammalian species.   Int J Cardiol 50: 3. 239-242 Jul  
Abstract: Nitric oxide (NO) is a potent vasorelaxing agent at nanomolar concentrations. At low nanomolar concentrations, NO also inhibits platelet aggregation, attenuates leukocyte adherence to the vascular endothelium, and quenches superoxide radicals. At high nanomolar concentrations, NO attenuates smooth muscle cells growth and stimulates proliferation of vascular endothelial cells. However, even at micromolar concentrations, NO fails to significantly alter cardiac contractility in isolated rat or cat cardiac muscle. Moreover, L-arginine, even at millimolar concentrations, fails to exert a decrease in cardiac contractility significantly greater than that produced by D-arginine.
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PMID 
S Kanwar, R C Woodman, M C Poon, T Murohara, A M Lefer, K L Davenpeck, P Kubes (1995)  Desmopressin induces endothelial P-selectin expression and leukocyte rolling in postcapillary venules.   Blood 86: 7. 2760-2766 Oct  
Abstract: Desmopressin, (DDAVP; 1-desamino-8-D-arginine vasopressin) increases the release and activity of von Willebrand factor (vWF); however, its effects on the other major constituent of endothelial Weibel-Palade bodies, P-selectin, has not been investigated. DDAVP-induced P-selectin expression may explain DDAVP's efficacy in bleeding disorders in which vWF levels are normal. Therefore, the objective of this study is to assess the effect of DDAVP on P-selectin expression on endothelial cells of postcapillary venules in vivo and on human umbilical vein endothelium in vitro, and to determine whether DDAVP has direct effects on leukocyte behavior in postcapillary venules. DDAVP (0.1 and 1.0 microgram/mL) induced a significant but transient increase in P-selectin expression on human umbilical vein endothelial cells as well as on rat and human platelets. Immunohistochemical analysis of rat postcapillary venules showed that in contrast to saline, DDAVP injection (1 microgram/kg, intravenous) induced significant endothelial P-selectin expression. DDAVP administration also induced a rapid and significant increase in leukocyte rolling in rat mesenteric venules in vivo. This response was entirely dependent on P-selectin, as an anti-P-selectin antibody rapidly reversed the DDAVP-induced increase in leukocyte rolling. DDAVP induced leukocyte rolling in medium (20 to 40 microns) and large (> 40 microns), but not small (< 20 microns), postcapillary venules. In animals that were treated with DDAVP, there was a steady and significant increase in leukocyte adhesion. This study shows that DDAVP can directly induce P-selectin expression on endothelium in vitro and in vivo and that the latter response is capable of supporting prolonged leukocyte rolling in rat postcapillary venules.
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PMID 
M Buerke, T Murohara, A M Lefer (1995)  Cardioprotective effects of a C1 esterase inhibitor in myocardial ischemia and reperfusion.   Circulation 91: 2. 393-402 Jan  
Abstract: BACKGROUND: Myocardial injury after ischemia and reperfusion can be attributed largely to the effects of polymorphonuclear leukocytes (PMN). The complement system plays an important role as a chemotactic agent, affecting adhesion molecule expression and neutrophil accumulation. METHODS AND RESULTS: In the present study, the cardioprotective effects of C1 esterase inhibitor (C1 INH) were examined in a feline model of myocardial ischemia and reperfusion (90 minutes of ischemia followed by 270 minutes of reperfusion). C1 INH (15 mg/kg) administered 10 minutes before reperfusion significantly attenuated myocardial necrosis compared with vehicle (10 +/- 2% and 29 +/- 2% necrosis as a proportion of area at risk, respectively; P < .01). Myocardial preservation was also related to reduced plasma accumulation of creatine kinase activity. C1 INH treatment resulted in improved recovery of cardiac contractility and preservation of coronary vascular endothelial function, as assessed by relaxation in response to acetylcholine, compared with contractility and preservation of endothelial function in vehicle-treated animals (69 +/- 6% and 20 +/- 4% relaxation, respectively; P < .01). In addition, cardiac myeloperoxidase activity (an index of PMN accumulation) in the ischemic area was significantly reduced after C1 INH treatment. Furthermore, immunohistochemical analysis of ischemic-reperfused myocardial tissue demonstrated deposition of the first component of the classic complement pathway, C1q, on cardiac myocytes and coronary vessels. CONCLUSIONS: Blocking of the classic complement pathway by C1 INH appears to be an effective means of preserving ischemic myocardium from reperfusion injury. The mechanism of this cardioprotective effect appears to be inhibition of PMN-endothelium interaction; this inhibition leads to preservation of normal endothelial function, which results in reduced cardiac necrosis.
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PMID 
T Murohara, M Buerke, J Margiotta, F Ruan, Y Igarashi, S Hakomori, A M Lefer (1995)  Myocardial and endothelial protection by TMS in ischemia-reperfusion injury.   Am J Physiol 269: 2 Pt 2. H504-H514 Aug  
Abstract: N,N,N-trimethylsphingosine (TMS), a stable synthetic sphingosine derivative, was investigated in a feline model of myocardial ischemia (90 min) and reperfusion (270 min) injury. TMS (60 micrograms/kg), administered intravenously 10 min before reperfusion, significantly attenuated myocardial necrosis (15 +/- 3 vs. 31 +/- 4% necrosis of area at risk, P < 0.01) and cardiac myeloperoxidase activities, a marker of neutrophil accumulation, compared with vehicle-treated cats. Endothelium-dependent relaxation to acetylcholine in ischemic-reperfused coronary artery rings treated with TMS was also significantly preserved compared with vehicle (73 +/- 4 vs. 34 +/- 4% vasorelaxation, P < 0.01). Polymorphonuclear neutrophil (PMN) adherence to coronary endothelium 270 min after reperfusion was markedly attenuated in the TMS group compared with vehicle-treated cats (37 +/- 5 vs. 76 +/- 5 PMN/mm2, P < 0.01). TMS also attenuated upregulation of P-selectin on coronary venular endothelium by immunohistochemistry. This was consistent with in vitro findings that TMS attenuates PMN adherence to thrombin-stimulated coronary endothelium and P-selectin upregulation on thrombin-stimulated cat platelets. A sphingolipid derivative, TMS at physiological concentrations exerts cardioprotective actions and preserves coronary endothelial function following myocardial ischemia and reperfusion in vivo. The effects appear to be mediated by the inhibition of PMN-endothelial interaction and subsequent accumulation into the ischemic myocardium. Thus TMS may be a useful agent in attenuating myocardial reperfusion injury.
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PMID 
K Kugiyama, T Murohara, H Yasue, T Kimura, N Sakaino, M Ohgushi, S Sugiyama, K Okumura (1995)  Increased constrictor response to acetylcholine of the isolated coronary arteries from patients with variant angina.   Int J Cardiol 52: 3. 223-233 Dec  
Abstract: The aim of this study was to determine whether isolated coronary arteries from patients with variant angina show hyperreactivity and/or supersensitivity to acetylcholine in vitro. Coronary arterial rings were obtained at autopsy within 3 h after death from six coronary arteries having spasm in four patients with variant angina and from 22 coronary arteries in 14 control patients with non-cardiac death. The coronary rings were suspended in the organ chamber filled with Krebs Henseleit solution bubbled with 95% O2 + 5% CO2, and their isometric tensions were monitored. Arterial rings isolated from both the patients with variant angina and the controls contracted dose-dependently in response to acetylcholine (10(-9)-10(-5) mol/l). EC50 of acetylcholine (i.e. concentration producing 50% of maximum contraction) was not significantly different between the coronary arteries from patients with variant angina and those from controls, but maximum contraction elicited by acetylcholine (expressed as a percentage of the contraction elicited by 60 mmol/l KCl) was significantly greater in the coronary arteries from patients with variant angina than those from controls. In conclusion, the isolated coronary arteries from patients with variant angina have hypercontractile reactivity to acetylcholine. This intrinsic alteration of the coronary reactivity to acetylcholine may play a role in the genesis of coronary spasm occurring in the situations of enhanced parasympathetic nervous discharge.
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PMID 
T W Gauthier, R Scalia, T Murohara, J P Guo, A M Lefer (1995)  Nitric oxide protects against leukocyte-endothelium interactions in the early stages of hypercholesterolemia.   Arterioscler Thromb Vasc Biol 15: 10. 1652-1659 Oct  
Abstract: We studied the effects of CAS1609, a nitric oxide donor, on leukocyte-endothelial interactions during the early stages of hypercholesterolemia in rat mesenteric microcirculation. Rats were randomly divided into four groups: (a) rats fed control diet, (b) rats fed control diet while receiving CAS1609, (c) rats fed a high-cholesterol (HC) diet and given C93-4845 (an inactive control compound), and (d) rats fed an HC diet and given CAS1609. Both HC groups developed significantly elevated plasma cholesterol levels compared with rats fed the control diet. Intravital microscopy of mesenteric venules revealed a significant increase in leukocyte rolling and adherence in the untreated HC rats compared with control rats (P < .01). This was significantly attenuated in the HC rats given CAS1609. The HC rats given C93-4845 also developed aortic endothelial dysfunction (ie, impaired relaxation to acetylcholine or ADP) that was significantly prevented by CAS1609 infusion (P < .02). Immunohistochemical staining of ileum demonstrated significantly enhanced localization of P-selectin and intercellular adhesion molecule-1 (ICAM-1) on venular endothelium in the untreated HC rats compared with control rats (P < .01). However, P-selectin and ICAM-1 expression were significantly attenuated in HC rats given CAS1609 (P < .05 and P < .01, respectively). Thus, hypercholesterolemia induces microvascular dysfunction characterized by loss of endothelium-derived nitric oxide, increased rolling and adherence of leukocytes, and increased expression of P-selectin and ICAM-1. Infusion of CAS1609 significantly attenuated these changes due to hypercholesterolemia. Our data suggest that nitric oxide plays a significant role in the prevention of the early endothelial dysfunction observed in hypercholesterolemia.
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PMID 
T Murohara, J Margiotta, L M Phillips, J C Paulson, S DeFrees, S Zalipsky, L S Guo, A M Lefer (1995)  Cardioprotection by liposome-conjugated sialyl Lewisx-oligosaccharide in myocardial ischaemia and reperfusion injury.   Cardiovasc Res 30: 6. 965-974 Dec  
Abstract: OBJECTIVES: Selectins are important adhesion molecules which utilize a carbohydrate ligand such as sialyl Lewisx (SLex). Our objective was to study the effects of a liposome-conjugated SLex (Lipo-SLex) in myocardial ischaemia (MI) and reperfusion (R) injury in order to further clarify the actions of this carbohydrate. METHODS: We studied the efficacy of Lipo-SLex in a feline model of MI (90 min) and R (270 min) injury in vivo. Lipo-SLex (400 micrograms SLex/kg, iv) was administered intravenously 10 min prior to R. We also utilized an in vitro system of neutrophil adherence to thrombin-stimulated coronary endothelium to validate the efficacy of Lipo-SLex. RESULTS: Lipo-SLex significantly attenuated myocardial necrosis (8.6 +/- 1.2 vs. 29.5 +/- 3.1% of area-at-risk, P < 0.01) and plasma creatine kinase activities (P < 0.01) compared to vehicle (liposome alone). Moreover, endothelium-dependent relaxation to acetylcholine and A23187 in ischaemic-reperfused coronary rings obtained from cats treated with Lipo-SLex was significantly preserved compared to cats given liposomes without SLex (P < 0.01). After reperfusion, ex vivo PMN adherence to ischaemic-reperfused coronary endothelium was significantly increased in vehicle-treated cats, however, this was significantly attenuated in Lipo-SLex-treated cats (82 +/- 7 vs. 28 +/- 3 PMNs/mm2, P < 0.01). Myeloperoxidase activity in the ischaemic myocardium, a marker of PMN accumulation, was also significantly attenuated in Lipo-SLex-treated cats compared to liposomes without SLex (P < 0.01). CONCLUSIONS: Liposome-conjugated SLex-oligosaccharide attenuates myocardial necrosis and preserves coronary endothelial function following MI/R in vivo. The mechanism appears to be mediated by inhibition of the initial PMN-endothelial interaction and eventual accumulation into the ischaemic cardiac tissue. The liposome-SLex complex may be an efficient drug formulation for acute inflammatory diseases.
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PMID 
T Murohara, S J Parkinson, S A Waldman, A M Lefer (1995)  Inhibition of nitric oxide biosynthesis promotes P-selectin expression in platelets. Role of protein kinase C.   Arterioscler Thromb Vasc Biol 15: 11. 2068-2075 Nov  
Abstract: Inhibition of NO synthesis promotes P-selectin expression on endothelial cells; however, the precise mechanism is unclear. Because No has been shown to inhibit protein kinase C (PKC) activity, we examined the hypothesis that the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) stimulates P-selectin expression on platelets via PKC activation. Ten-minute incubation with either phorbol 12-myristate 13-acetate (PMA), thrombin, or L-NAME significantly increased P-selectin expression on platelets (as assessed by flow-cytometric analysis) and PKC activity of platelet membranes. Increased P-selectin expression induced by either PMA, thrombin, or L-NAME was significantly attenuated by the selective PKC inhibitor UCN-01 (7-hydroxystaurosporine). Furthermore, L-NAME-induced P-selectin expression was significantly attenuated by either L-arginine, 8-bromo-cGMP, or sodium nitroprusside (SNP). Interestingly, L-NAME further potentiated P-selectin upregulation by thrombin. L-NAME, thrombin, and PMA also significantly increased polymorphonuclear leukocyte adherence to the coronary artery endothelium, an effect that was significantly attenuated by the anti-P-selectin monoclonal antibody PB1.3 or by UCN-01, L-arginine, 8-bromo-cGMP or SNP but not by D-arginine or he nonblocking anti-P-selectin monoclonal antibody NBP1.6. These results indicate that inhibition of NO synthesis induces rapid P-selectin expression, which appears to be at least partially mediated by PKC activation in platelets. Similar effects and mechanisms of L-NAME on P-selectin function were also observed in endothelial cells, another site of P-selectin expression.
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PMID 
T Murohara, J P Guo, J A Delyani, A M Lefer (1995)  Cardioprotective effects of selective inhibition of the two complement activation pathways in myocardial ischemia and reperfusion injury.   Methods Find Exp Clin Pharmacol 17: 8. 499-507 Oct  
Abstract: The complement (C) system-mediated neutrophil activation, adhesion to the coronary endothelium and accumulation into cardiac tissue are key steps in the pathogenesis of myocardial ischemia-reperfusion (MI/R) injury. We examined the differential role of the classical and the alternative complement pathway in MI/R injury in vivo. Rats were subjected to 20 min of myocardial ischemia followed by 24 h of reperfusion. Either a classical pathway inhibitor [C1 esterase inhibitor (C1-INH) (15 mg/kg)] or an alternative pathway inhibitor soluble complement receptor 1 (sCR1)[des-LHR-A](15 mg/kg) or their vehicle were administered intravenously 1 min prior to reperfusion, and myocardial necrosis (creatine kinase loss) and neutrophil accumulation, cardiac myeloperoxidase activity, were examined. C1-INH significantly attenuated cardiac creatine kinase loss compared to MI/R rats given only vehicle (p < 0.05) 24 h after reperfusion. An alternative pathway inhibitor, sCR1 [des-LHR-A] attenuated myocardial injury to a lesser extent, although it was not significantly different from the value for C1-INH or vehicle. Besides cardiac myeloperoxidase activity, the ischemic cardiac tissue was significantly attenuated by both C1-INH and sCR1[desLHR-A] (p < 0.05 vs. vehicle). Both the classical and alternative pathways may contribute to MI/R injury via a neutrophil-dependent mechanism in vivo. Selective inhibition of the classical pathway of complement activation seems to be slightly more effective in limiting necrotic MI/R injury than the selective alternative pathway inhibition in this 24 h model of reperfusion injury, but equal doses of each inhibitor attenuated neutrophil accumulation.
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1994
 
PMID 
T Murohara, M Buerke, A M Lefer (1994)  Polymorphonuclear leukocyte-induced vasocontraction and endothelial dysfunction. Role of selectins.   Arterioscler Thromb 14: 9. 1509-1519 Sep  
Abstract: The roles of selectin adhesion molecules (P- and L-selectin) and their counterreceptor sialyl Lewisx were investigated in polymorphonuclear leukocyte (PMN)-induced cat coronary vasocontraction and endothelial dysfunction. Unstimulated autologous PMNs (10(6) cells/mL) were added to organ chambers containing cat coronary artery rings stimulated with either thrombin (2 U/mL) or hydrogen peroxide (100 mumol/L). PMNs elicited a significant vasocontraction in thrombin- (119 +/- 14 mg) and hydrogen peroxide- (132 +/- 15 mg) stimulated coronary rings. This PMN-induced vasocontraction was significantly attenuated by pretreatment with either an anti-P-selectin, an anti-L-selectin monoclonal antibody (ie, MAb PB 1.3 and MAb DREG-200), or a sialyl Lewis(x)-containing oligosaccharide (SLe(x)-OS). Endothelial function as assessed by endothelium-dependent vasorelaxation to acetylcholine was also significantly attenuated after PMN-induced vasocontraction in stimulated coronary rings. This endothelial dysfunction was significantly prevented by either PB 1.3, DREG-200, or SLe(x)-OS. In contrast, endothelium-independent relaxation to acidified sodium nitrite was not altered by PMN incubation, indicating that vascular smooth muscle function was unaffected. Adherence of PMNs to coronary endothelium also significantly increased following stimulation of endothelium with either thrombin or hydrogen peroxide, but this was significantly attenuated by PB 1.3, DREG-200, or SLe(x)-OS. Thus, PMN-endothelial interaction mediated by either selectin adhesion molecules (ie, P-selectin and L-selectin) or sialyl Lewis(x) may play an important role in PMN-induced vasocontraction and endothelial dysfunction. This mechanism may be important in the early endothelial dysfunction observed following reperfusion of an ischemic coronary vasculature.
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PMID 
T Murohara, K Kugiyama, M Ohgushi, S Sugiyama, H Yasue (1994)  Cigarette smoke extract contracts isolated porcine coronary arteries by superoxide anion-mediated degradation of EDRF.   Am J Physiol 266: 3 Pt 2. H874-H880 Mar  
Abstract: To test whether cigarette smoke extract (CSE) influences the endothelial regulation of vascular tone in vitro, pig coronary arterial rings were incubated in organ chambers and isometric tension changes were examined. CSE was prepared by bubbling mainstream smoke of one filter cigarette into phosphate-buffered saline (2 ml). Fresh CSE (3.3, 10, and 30 microliters/ml) elicited initial contraction and subsequent relaxation during stable contraction to prostaglandin F2 alpha (PGF2 alpha). Initial contraction to CSE was dependent on the presence of endothelium, whereas subsequent relaxation was endothelium independent. Initial contraction was significantly attenuated by superoxide dismutase (SOD), methylene blue, but not by catalase. Prior inhibition of the basal release of endothelium-derived relaxing factor by NG-monomethyl-L-arginine also inhibited the initial contraction, and this inhibition was reversed by coincubation with L-arginine but not D-arginine. Subsequent relaxation was significantly potentiated by SOD but was markedly attenuated by methylene blue. CSE reduced ferricytochrome c, and this reduction was significantly inhibited by SOD. In conclusion, CSE induced biphasic tension change, initial contraction, and subsequent relaxation during stable contraction to PGF2 alpha in isolated pig coronary arteries. The initial contraction may be, at least in part, mediated through the degradation of basally released endothelium-derived relaxing factor (nitric oxide) by superoxide anions derived from CSE.
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PMID 
M Buerke, A S Weyrich, T Murohara, C Queen, C K Klingbeil, M S Co, A M Lefer (1994)  Humanized monoclonal antibody DREG-200 directed against I-selectin protects in feline myocardial reperfusion injury.   J Pharmacol Exp Ther 271: 1. 134-142 Oct  
Abstract: Polymorphonuclear leukocytes (i.e. neutrophils) significantly mediate damage in myocardial ischemia followed by reperfusion. In the present study, the cardioprotective effects of a humanized form of a monoclonal antibody directed against L-selectin designated monoclonal antibody (mAb) HuDREG-200 were examined in a feline model of 90-min myocardial ischemia followed by 270 min of reperfusion. In preliminary studies, flow cytometric analysis indicated that HuDREG-200 binds to feline neutrophils. In vitro administration of mAb HuDREG-200 significantly inhibited (P < .01) adherence of unstimulated neutrophils to ischemic-reperfused coronary endothelium in a concentration-dependent manner. Humanized DREG-200 (2 mg/kg) administered 10 min before reperfusion significantly attenuated myocardial necrosis compared to an isotype-matched humanized control mAb (HuABL364) which does not bind to L-selectin (14 +/- 3 vs. 29 +/- 3% necrosis/area-at-risk, P < .01), representing a 52% reduction in myocardial necrosis. This myocardial preservation also was related to reduced creatine kinase release and improved recovery of cardiac contractility (i.e. left ventricular dP/dtmax). Moreover, endothelial function, as assessed by relaxation to acetylcholine, also was significantly preserved in ischemic-reperfused coronary arteries isolated from cats treated with mAb HuDREG-200 compared to mAb HuABL364 (68 +/- 6 vs. 18 +/- 5, P < .01). Thus, a humanized anti-L-selectin mAb appears to be an effective means of preserving the ischemic myocardium from reperfusion injury and of preserving myocardial contractile function, at least during the early reperfusion period.
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PMID 
T Murohara, K Kugiyama, M Ohgushi, S Sugiyama, Y Ohta, H Yasue (1994)  LPC in oxidized LDL elicits vasocontraction and inhibits endothelium- dependent relaxation.   Am J Physiol 267: 6 Pt 2. H2441-H2449 Dec  
Abstract: Oxidized low-density lipoprotein (ox-LDL) plays an important role in the development of atherosclerosis and potentially influences the endothelial regulation of vasomotor tone. We have recently shown that lysophosphatidylcholine (LPC), a lysophospholipid contained in ox-LDL, has various pathophysiological effects. We further examined the role of LPC in the ox-LDL-induced vasoactivity in isolated pig coronary arteries. Copper-induced ox-LDL but not native LDL (n-LDL) elicited endothelium-dependent contraction during plateau contraction evoked by prostaglandin F2 alpha. Lipid extracted from ox-LDL (ox-LDL-lipid) also induced vasocontraction, but lipid of n-LDL (n-LDL-lipid) did not influence tone. When LPC was depleted from ox-LDL (i.e., defatted albumin- or phospholipase B-treated ox-LDL), vasocontraction was significantly attenuated. Synthetic palmitoyl LPC also induced endothelium-dependent vasocontraction, mimicking the response elicited by ox-LDL, but phosphatidylcholine, which exists in n-LDL and is converted to LPC during oxidative modification of LDL, did not influence the tone. Contraction to either ox-LDL or LPC was significantly attenuated by NG-monomethyl-L-arginine but not by indomethacin or superoxide dismutase. Forty minutes of incubation of coronary rings with either ox-LDL or LPC significantly attenuated endothelium-dependent vasorelaxation to thrombin without affecting vasorelaxation to endothelium-independent vasodilator nitroglycerin. In conclusion, LPC contained in lipid fraction of ox-LDL caused endothelium-dependent contraction and inhibited endothelium-dependent relaxation in isolated pig coronary arteries. The vasocontraction might be at least in part caused by LPC-mediated inhibition of endothelium-derived nitric oxide release.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID 
A M Lefer, T Murohara, M Buerke (1994)  Effects of taprostene on neutrophil-endothelial interactions in isolated coronary arteries.   Methods Find Exp Clin Pharmacol 16: 9. 623-631 Nov  
Abstract: We examined the effects of taprostene (2.5 x 10(-8) M to 1 x 10(-7) M), a stable prostacyclin analog, on PMN-endothelial interaction (i.e., adherence) and subsequent vasocontraction and endothelial dysfunction. Taprostene effectively inhibited the adherence of leukotriene B4-stimulated autologous cat polymorphonuclear (PMN) leukocytes to isolated cat coronary artery endothelium. Taprostene also inhibited coronary artery vasocontraction to leukotriene B4-stimulated PMNs (p < 0.01). In isolated coronary artery rings stimulated with either 2 U/ml of thrombin or 100 microM hydrogen peroxide (H2O2), adherence of unstimulated PMNs to coronary endothelium was significantly increased, resulting in vasocontraction and subsequent endothelial dysfunction. However, taprostene (1 x 10(-7) M) significantly attenuated unstimulated PMN adherence to stimulated coronary endothelium. This antiadherence action effectively attenuated PMN-induced coronary artery vasocontraction (p < 0.01) and significantly blunted the subsequent PMN-induced endothelial dysfunction (p < 0.01) characterized by a loss of endothelium-derived nitric oxide (NO). Thus, taprostene exerts a profound inhibitory effect on PMN-endothelium interaction and subsequent PMN-mediated coronary endothelial dysfunction, which may be beneficial in ischemia-reperfusion and other inflammatory states.
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PMID 
A S Weyrich, X L Ma, M Buerke, T Murohara, V E Armstead, A M Lefer, J M Nicolas, A P Thomas, D J Lefer, J Vinten-Johansen (1994)  Physiological concentrations of nitric oxide do not elicit an acute negative inotropic effect in unstimulated cardiac muscle.   Circ Res 75: 4. 692-700 Oct  
Abstract: We examined the effect of several nitric oxide (NO) donors, authentic NO gas, and L-arginine in isolated cat and rat papillary muscles. We did not observe significant inotropic effects in response to any NO donor (ie, SPM-5185, C87-3754, and S-nitroso-N-acetylpenicillamine [SNAP]) from 1 nmol/L to 100 mumol/L. Similarly, authentic NO, at concentrations far in excess of those that maximally dilate the coronary vasculature (ie, 500 nmol/L), also failed to exert a detectable inotropic effect in these preparations. However, in the presence of 5 mumol/L norepinephrine, 500 nmol/L NO exerted a 12 +/- 3% decrease in isolated rat papillary muscle contractility (P < .05). Addition of L-arginine up to 25 mmol/L exerted no inotropic effects in isolated rat papillary muscles. However, at 50 mmol/L, L-arginine decreased contractile force by 21 +/- 4% (P < .01). On further examination, the negative inotropic effect of 50 mmol/L L-arginine appeared to be nonspecific, since the inactive stereoisomer, D-arginine, at 50 mmol/L exerted the same effect. Further studies in isolated adult rat cardiac myocytes elicited similar results, in that 50 mmol/L of L- and D-arginine equally decreased contraction amplitude and the underlying cytosolic calcium transient. Moreover, 500 nmol/L of the NO donor SPM-5185 only modestly decreased contraction amplitude or intracellular calcium in isolated rat cardiac myocytes. These results indicate that administration of physiological concentrations of exogenous NO does not acutely depress the inotropic state of the rat or cat heart to a physiologically significant extent.(ABSTRACT TRUNCATED AT 250 WORDS)
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1993
 
PMID 
T Murohara, K Kugiyama, S Sugiyama, M Ohgushi, H Yasue (1993)  Activated human polymorphonuclear leukocytes elicit endothelium-dependent contraction in isolated pig coronary arteries.   J Cardiovasc Pharmacol 21: 5. 760-766 May  
Abstract: Interaction between activated human polymorphonuclear leukocytes (PMNL) and endothelial regulation of isolated pig coronary artery tone was examined. PMNL were isolated from venous blood of healthy human volunteers. Pig coronary artery rings were incubated in an organ chamber, and isometric tension changes induced by opsonized zymosan (1 mg/ml)-activated PMNL were examined. Activated PMNL elicited dose-dependent contraction (maximum value 45.9 +/- 4.1% of precontraction, mean +/- SEM] in prostaglandin F2 alpha (PGF2 alpha)-precontracted rings. The contraction was markedly attenuated by superoxide dismutase (SOD 100 U/ml) to 9.9 +/- 2.4% (p < 0.001), but not by catalase (1,000 U/ml). After inhibition of basal production of endothelium-derived relaxing factor (EDRF) (nitric oxide, NO) by endothelial removal or by treatment of an inhibitor of NO synthase, NG-monomethyl-L-arginine (L-NMMA), PMNL also failed to induce the contraction. A 5-lipoxygenase inhibitor (AA-861) and a cyclooxygenase inhibitor (indomethacin) did not alter the contraction to activated PMNL significantly. Time course of oxygen free radical release from PMNL measured by luminol-dependent chemiluminescence was closely synchronized with that of the endothelium-dependent contraction elicited by PMNL. In each preparation of PMNL, the maximum luminescence count and the maximum contraction induced by activated PMNL showed significant positive correlation quantitatively (r = 0.958, p < 0.001). Activated human PMNL elicited endothelium-dependent contraction in isolated pig coronary arteries. The contraction may be mediated through inactivation of basal production of EDRF (NO) by superoxide anions released from PMNL.
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PMID 
M Ohgushi, H Yasue, K Kugiyama, T Murohara, N Sakaino (1993)  Contraction and endothelium dependent relaxation via alpha adrenoceptors are variable in various pig arteries.   Cardiovasc Res 27: 5. 779-784 May  
Abstract: OBJECTIVE: The aim was to examine differences in the vascular response to alpha adrenoceptor stimulation on both smooth muscle and endothelium among large arteries perfusing various organs. METHODS: In ring preparations of coronary, carotid, iliac, mesenteric, and renal arteries from pigs (n = 24), the magnitudes of contraction to noradrenaline (with beta blocker), with or without endothelium, and endothelium dependent relaxation to noradrenaline (with alpha 1 and beta blocker) were compared in vitro. RESULTS: In both endothelium-intact and denuded groups, the contractions to noradrenaline were significantly smaller in coronary and carotid arteries than in iliac, mesenteric, and renal arteries. The presence of endothelium significantly suppressed the contractions in coronary and carotid arteries, but did not affect the contractions in iliac, mesenteric, and renal arteries. The endothelium dependent relaxations to noradrenaline, which were abolished by LNMMA, were more prominent in coronary and carotid arteries than in iliac, mesenteric, and renal arteries. CONCLUSIONS: The contractions via alpha adrenoceptors were small, and endothelium dependent relaxations via alpha 2 adrenoceptors were large, in the coronary and carotid arteries, which perfuse the vital organs (heart and brain), as compared with those in iliac, mesenteric, and renal arteries. These results suggest that in the state of activation of the sympathetic nervous system, arterial tone in response to alpha adrenoceptor stimulation may be regulated not only by alpha adrenoceptors on vascular smooth muscle but also by those on endothelium, through release of endothelium derived relaxing factor (EDRF) via alpha 2 adrenoceptors.
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PMID 
M Ohgushi, K Kugiyama, K Fukunaga, T Murohara, S Sugiyama, E Miyamoto, H Yasue (1993)  Protein kinase C inhibitors prevent impairment of endothelium-dependent relaxation by oxidatively modified LDL.   Arterioscler Thromb 13: 10. 1525-1532 Oct  
Abstract: The mechanism(s) of inhibition of endothelium-dependent relaxation (EDR) by oxidized low-density lipoprotein (Ox-LDL) was examined in isolated porcine coronary arteries and rabbit aortas. Incubation with Ox-LDL but not native LDL caused the inhibition of thrombin- or acetylcholine-induced EDR, whereas A23187-induced EDR was preserved after incubation with Ox-LDL. Lysophosphatidylcholine (lysoPC), which was abundant in Ox-LDL and was found to be transferred from Ox-LDL to endothelial cells, also caused the inhibition of EDR in response to thrombin or acetylcholine but not to A23187. Ox-LDL depleted of lysoPC, which was prepared by phospholipase B, failed to inhibit the vasorelaxation. Coincubation with staurosporine or calphostin C, potent inhibitors of protein kinase C, attenuated the EDR inhibition by Ox-LDL or lysoPC. Phorbol 12-myristate 13-acetate, a specific protein kinase C activator, caused the EDR inhibition, and its effect was attenuated by staurosporine or calphostin C. Furthermore, lysoPC was capable of activating protein kinase C purified from cultured porcine endothelial cells. In conclusion, protein kinase C activation plays a role in the inhibition of surface receptor-mediated EDR by Ox-LDL, and lysoPC transferred from Ox-LDL to endothelial cells may be involved in the activation of protein kinase C.
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1992
 
PMID 
K Nakao, H Yasue, K Fujimoto, K Okumura, H Yamamoto, Y Hitoshi, T Murohara, K Takatsu, E Miyamoto (1992)  Increased expression of atrial myosin light chain 1 in the overloaded human left ventricle: possible expression of fetal type myocytes.   Int J Cardiol 36: 3. 315-328 Sep  
Abstract: We examined the isoforms of myosin light chain 1 in the human left ventricles using pyrophosphate and sodium dodecyl sulfate polyacrylamide gel electrophoresis, peptide mapping, and immunoblotting with monoclonal antibodies against human atrial light chain 1. The relationship between hemodynamic parameters and light chain 1 isoform composition was compared among groups of patients with hypertrophic cardiomyopathy (n = 8), dilated cardiomyopathy (n = 9) and aortic stenosis (n = 5), and controls (n = 6). (1) The light chain 1, which differed from ventricular light chain 1 found in the normal adult ventricle, was highly expressed in the overload left ventricle, and was identical to atrial and fetal ventricular light chain 1 with respect to the physiochemical and immunological properties. (2) The expression of atrial/fetal light chain 1 was augmented in the subendocardial area in comparison with the mid- or subepicardial areas in the hypertrophied left ventricles. (3) The values (%) of the relative expression of atrial/fetal light chain 1 to total light chains 1 determined by densitometric analysis were significantly higher in patients with dilated cardiomyopathy (40.2 +/- 5.8) and those with aortic stenosis (43.1 +/- 6.2) than in the controls (16.9 +/- 2.5) (p less than 0.01), but there was no significant difference between the patients with hypertrophic cardiomyopathy (28.0 +/- 3.7) and the controls. (4) The values of the ratio significantly correlated with those of peak circumferential wall stress (r = 0.53, p less than 0.005). These results suggest that atrial/fetal light chain 1 is expressed in the left ventricles in response to the increased hemodynamic load.
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PMID 
K Kugiyama, M Ohgushi, S Sugiyama, T Murohara, K Fukunaga, E Miyamoto, H Yasue (1992)  Lysophosphatidylcholine inhibits surface receptor-mediated intracellular signals in endothelial cells by a pathway involving protein kinase C activation.   Circ Res 71: 6. 1422-1428 Dec  
Abstract: Lysophosphatidylcholine (lysoPC) transferred from oxidatively modified low density lipoprotein (Ox-LDL) to the endothelial surface membrane has been shown to produce a selective unresponsiveness to cell surface receptor-regulated endothelium-dependent relaxation (EDR) in the rabbit aorta. To determine its mechanism we examined the effects of lysoPC on endothelial surface receptor-mediated transmembrane signals. Incubation for 1 minute with palmitoyl lysoPC (5-10 microM) decreased thrombin (Th, 2 units/ml)- or histamine (His, 0.1 mM)-stimulated inositol 1,4,5-trisphosphate (IP3) production in primary cultures of human umbilical vein endothelial cells (HUVECs). LysoPC also decreased Th- or His-induced intracellular calcium ([Ca2+]i, fura 2) elevation. Pretreatment with protein kinase C (PKC) inhibitors staurosporine (100 nM) or H-7 (50 microM) prevented the inhibitory actions of lysoPC, but HA-1004 had no effect. Incubation for 5 minutes with phorbol 12-myristate 13-acetate (PMA, 100 nM) produced the inhibitory actions on the Th- or His-induced intracellular signals, which closely mimic those exhibited by lysoPC. However, the inhibitory effect of lysoPC was lost in cells that were depleted of PKC by pretreatment for 24 hours with 100 nM PMA. Furthermore, incubation of the cells for 1 minute with lysoPC stimulated PKC activity in the membrane fraction. In organ chamber experiments with porcine coronary artery rings, pretreatment with staurosporine (20 nM) attenuated lysoPC-induced impairment of EDR in response to Th. These results indicate that lysoPC, which accumulates in Ox-LDL and atherosclerotic arterial walls, inhibits the early transmembrane signaling pathway in endothelial cells, and PKC activation could at least partially be involved in the negative regulation by lysoPC.(ABSTRACT TRUNCATED AT 250 WORDS)
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1991
 
PMID 
T Murohara, H Yasue, M Ohgushi, N Sakaino, M Jougasaki (1991)  Age related attenuation of the endothelium dependent relaxation to noradrenaline in isolated pig coronary arteries.   Cardiovasc Res 25: 12. 1002-1009 Dec  
Abstract: STUDY OBJECTIVE--The aim was to investigate the relationship between vascular aging and endothelial regulation of the vascular tone by various agonists in isolated pig coronary arteries. EXPERIMENTAL MATERIALS AND DESIGN--Coronary artery rings from young (4-6 month old) and aged (3-4 years old) Yorkshire pigs were studied under isometric tension by organ chamber experiments. Cumulative concentration-response curves were obtained for vasorelaxing agents including noradrenaline (with beta blocker), substance P, bradykinin, and glyceryl trinitrate in rings precontracted with prostaglandin F2 alpha (PGF2 alpha). The degree of atherosclerosis of the coronary arteries was examined by light microscopy after the pharmacological experiments. MEASUREMENTS AND MAIN RESULTS--In the presence of propranolol (3 x 10(-6)M), noradrenaline (10(-8)-10(-5)M) caused endothelium dependent relaxation. The maximum relaxation was significantly greater in the young [45.4(SEM 2.5)% of the magnitude of precontraction induced by PGF2 alpha] than in the aged group [26.9(3.0)%] (p less than 0.001). However, magnitudes of relaxation to substance P, bradykinin, and glyceryl trinitrate were not significantly different between the young and the aged groups. The alpha 2 antagonist yohimbine (3 x 10(-6)M) inhibited the endothelium dependent relaxation to noradrenaline, but the alpha 1 antagonist prazosin (10(-6)M) failed to inhibit the response. Gossypol (3 x 10(-5)M) and methylene blue (10(-5)M), both inhibitors of endothelium dependent relaxation, abolished alpha 2 adrenoceptor mediated relaxation, but a cyclo-oxygenase inhibitor indomethacin (10(-5)M) did not affect the response. Histologically almost all young pig coronary arteries were free of atherosclerotic changes, whereas aged arteries had fatty streaks with slightly narrowed lumen in 22 of 38 rings (58%). The remaining aged pig coronary rings were free from atherosclerosis. Comparison of the endothelium dependent relaxation to noradrenaline between the rings with fatty streaks and those without lesions in the aged pigs suggested that the attenuated response was due both to vascular aging and to fatty streak development. CONCLUSIONS--The endothelium dependent relaxation to noradrenaline via the alpha 2 adrenoceptor was attenuated by vascular aging and also by fatty streak formation in isolated pig coronary arteries. Thus vascular aging may affect the sympathetic regulation of the coronary arterial tone by the attenuation of endothelium dependent relaxation to catecholamines via alpha 2 adrenoceptors.
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