Abstract: Vertebrates use adaptive mechanisms when exposed to physiologic stresses. However, the mechanisms of pigmentation regulation in response to physiologic stresses largely remain unclear. To address this issue, we developed a novel pigmentation model in adult zebrafish using coldwater exposure (cold zebrafish). When zebrafish were maintained at 17 °C, the pigmentation of their pigment stripes was reduced compared with zebrafish at 26.5 °C (normal zebrafish). In cold zebrafish, gene expression levels of tyrosinase and dopachrome tautomerase, which encode enzymes involved in melanogenesis, were down-regulated, suggesting that either down-regulation of melanin synthesis occurred or the number of melanophores decreased. Both regular and electron microscopic observation of zebrafish skin showed that the number of melanophores decreased, whereas aggregation of melanosomes was not changed in cold zebrafish compared with normal zebrafish. Taken together, we here show that cold exposure down-regulated adult zebrafish pigmentation through decreasing the number of melanophores and propose that the cold zebrafish model is a powerful tool for pigmentation research.
Abstract: (Full text is available at http://www.manu.edu.mk/prilozi). Introduction and objectives: The objective of this study is to identify the nuclear expression of the p53 protein in prostate cancer and to determine its relationship with clinico-pathological variables. Material and methods: The research included 83 patients, 43 of whom are pati-ents with prostate cancer who underwent radical prostatectomy and a control group of 40 patients with benign hyperplasia of the prostate in whom a transurethral resection or a transvesical prostatectomy was undertaken. In all cases the nuclear expression of p53 protein was evaluated. A hystopatological evaluation of the tumour characteristics and the data of the local progression of the cancer were undertaken in the research group. Results: The results show that the expression of the p53 protein does not have an important correlation with the preoperative PSA, but that it is in direct correlation with the malign potential of the cancer (Gleason score, Gleason sum, primary tumour) and with the features of the disease (metastatic lymph nodes, stage of the disease). Conclusion: p53 protein could be used as a valid biomarker in determining the malignant potential of the tumour and the prognosis of the disease. There is no practical use in predicting the extraprostatic extension. Key words: Prostate carcinoma, p53 protein, extra-capsular extension.
Abstract: The lack of cadaver organs for transplantation motivates some Balkan patients to go to developing countries to buy a kidney. We have followed 36 patients who received kidney transplants in Lahore and Rawalpindi, Pakistan. The patients had not been cleared for transplantation with a standard pre-transplant work-up: 80% were hepatitis-C virus (HCV) or HBsAg positive. During follow-up, seven patients died. Sixteen patients experienced wound infections with post-operative hernias, and three patients developed peri-renal hematomas. Six abscesses and four lymphoceles occurred, and four urinary fistulas were surgically treated. Nephrectomy was performed in three patients because of renal artery thrombosis. Nine patients developed active hepatitis C, and four patients manifested cytomegalovirus disease. Three patients developed steroid diabetes, and three patients experienced acute myocardial infarction. Nine patients had one or more rejection episodes. Urinary tract infection with Pseudomonas or Escherichia occurred frequently. The one-yr patient and graft survival rates were 80% and 68%, respectively. Paid unregulated renal transplantation is not recommended for both ethical reasons and because of an association with excessive morbidity and mortality.
Abstract: BACKGROUND: Chronic kidney disease (CKD) is associated with disorders of mineral and bone metabolism (MBD) which include renal osteodystrophy and vascular calcifications. This is of clinical concern because the high risk of cardiovascular (CVD) complications observed in uremic patients may be linked with bone disease. In this context, our aim was to characterize the bone lesions in CKD-apolipoprotein E-deficient mice (apoE(-/-)) and analyze their relationships with the vascular calcifications which these animals develop rapidly in this model. With ApoE being also involved in bone metabolism, we compared the effects of CRF on the bone of apoE(-/-) mice to those observed in wild type mice (WT) of the same genetic background, C57/BL6. METHODS: After CRF creation or sham surgery, 10week-old female apoE(-/-) and WT mice were randomized to 4 groups (n=10-14/group) and fed with standard diet. Eight weeks later, animals were euthanized. Serum, aorta and femur were sampled. Femurs were imaged with 3-dimensional microtomography (microCT) and processed for bone histomorphometry (BHM). Additional quantitative histology was performed on atherosclerotic and calcified lesions in the aortas of apoE(-/-) mice. RESULTS: First, apoE(-/-) mice exhibited higher cortical (10%) and trabecular (31%) bone mass than WT. CRF led to a further increase in trabecular BV/TV in WT and in apoE(-/-) mice (10.2% and 77.2%, respectively). We observed a similar increase in osteoid surface and osteoblastic parameters in CRF mice of both genotypes while resorption parameters were less augmented by CRF in apoE(-/-) mice. Finally, based on either BHM or microCT we found positive correlations between the extent of atheroclerotic lesions and bone volume parameters, and between the size of plaque calcification and osteoclast parameters in apoE(-/-) mice. CONCLUSION: ApoE deficiency is associated with an increase in bone mass and volumetric mineral density in 20week-old female mice. Bone mass is further increased, whereas bone mineral density is decreased, in response to CRF in association with histological features of osteitis fibrosa. Finally, our findings of correlations between changes in bone and aortic lesions in apoE(-/-) mice, are compatible with the hypothesis of a link between bone and vascular disease and require further study.
Abstract: Reduced serum levels of the calcification inhibitor fetuin-A associate with increased cardiovascular mortality in dialysis patients. Fetuin-A-deficient mice display calcification of various tissues but notably not of the vasculature. This absence of vascular calcification may result from the protection of an intact endothelium, which becomes severely compromised in the setting of atherosclerosis. To test this hypothesis, we generated fetuin-A/apolipoprotein E (ApoE)-deficient mice and compared them with ApoE-deficient and wild-type mice with regard to atheroma formation and extraosseous calcification. We assigned mice to three treatment groups for 9 wk: (1) Standard diet, (2) high-phosphate diet, or (3) unilateral nephrectomy (causing chronic kidney disease [CKD]) plus high-phosphate diet. Serum urea, phosphate, and parathyroid hormone levels were similar in all genotypes after the interventions. Fetuin-A deficiency did not affect the extent of aortic lipid deposition, neointima formation, and coronary sclerosis observed with ApoE deficiency, but the combination of fetuin-A deficiency, hyperphosphatemia, and CKD led to a 15-fold increase in vascular calcification in this model of atherosclerosis. Fetuin-A deficiency almost exclusively promoted intimal rather than medial calcification of atheromatous lesions. High-phosphate diet and CKD also led to an increase in valvular calcification and aorta-associated apoptosis, with wild-type mice having the least, ApoE-deficient mice intermediate, and fetuin-A/ApoE-deficient mice the most. In addition, the combination of fetuin-A deficiency, high-phosphate diet, and CKD in ApoE-deficient mice greatly enhanced myocardial calcification, whereas the absence of fetuin-A did not affect the incidence of renal calcification. In conclusion, fetuin-A inhibits pathologic calcification in both the soft tissue and vasculature, even in the setting of atherosclerosis.
Abstract: OBJECTIVE: Secondary hyperparathyroidism of chronic kidney disease promotes vascular calcification. Calcimimetics reduce serum parathyroid hormone, calcium (Ca), and phosphorus by calcium-sensing receptor (CaR) activation. Here we examined possible effects of the calcimimetic R-568 (R-568) on the progression of aortic calcification and atherosclerosis in apoE(-/-) mice with chronic renal failure (CRF) and the potential implication of aortic smooth muscle cell CaR. METHODS AND RESULTS: ApoE(-/-) mice were assigned to 3 CRF groups and 1 non-CRF group receiving daily gavage with R-568, calcitriol, or vehicle. Serum Ca and phosphorus and parathyroid gland volume of CRF mice were decreased by R-568, whereas elevated serum FGF23 and total cholesterol remained unchanged. Both aortic plaque and non-plaque calcification was lower in R-568 mice, and so was atherosclerotic plaque area fraction. In vitro, R-568 induced a decrease in smooth muscle cell calcification when cultured in high phosphate medium. This decrease was abolished in CaR-SiRNA-transfected cells. CONCLUSIONS: The calcimimetic R-568 delayed the progression of both aortic calcification and atherosclerosis in uremic apoE(-/-) mice. This effect was mediated via a better control of hyperparathyroidism including serum Ca and phosphorus. Direct vascular CaR activation also could have played a role in the observed effects.
Abstract: INTRODUCTION: Artificial penile nodules are defined as inert objects inserted beneath the skin of the penis to enhance the pleasure of female/male sexual partners during intercourse. AIM: The aim of this article is to present our experience in dealing with artificial penile bodies. We have also reviewed the pertinent literature focusing on social, motivational, and occupational characteristics of individuals adopting this sexual practice, diagnostic dilemmas and the surgical and health side effects of the implantation of artificial penile nodules. METHODS: We performed a computerized MEDLINE search followed by a manual bibliographic review of cross-references. These reports were analyzed and the important findings summarized. RESULTS: The phenomenon of inserting self-made artificial nodules beneath the skin of the penis was first described in the Kama Sutra, the classic Indian treatise on love. It is most commonly observed among men from Southeast Asia. The occurrence is much less common in western cultures, but it has been reported to occur in Romania, Germany, and among Fijians and Russian immigrants in Israel. Furthermore, four cases of self-inserted artificial penile bodies from our clinical practice are presented and discussed. CONCLUSIONS: The most common motive associated with foreign artificial bodies on the penis is sexual or erotic in nature and that is to enhance the pleasure of female or male sexual partners during sexual intercourse. Most of the reports involve members of low economic groups like gang members, soldiers, drug addicts, sailors, labor workers, and prisoners. Men suffer no serious side effects after insertion, although fixed beads can cause rupture of condoms. For women, the beads can cause abrasions and a few days of postcoital vaginal pain. Penis implants and inserts and other penis augmentation devices are potentially dangerous to both men and women, and of questionable value in bringing pleasure to either, and should be discouraged.
Abstract: Zebrafish kidney marrow (ZKM), which is equivalent to the haematopoietic bone marrow of mammals, produces all major blood cell types, which morphologically resemble their mammalian counterparts. To be able to exploit the advantages of zebrafish genetics for analysis of the general mechanisms controlling self-renewal, proliferation and lineage decisions of vertebrate haematopoetic cell populations, it is essential to develop a simple surgical technique in order to identify, dissect and take out the ZKM without contamination with other surrounding tissues and cells. However, the size of adult zebrafish is small (average size: 2.5 cm) and the ZKM is an extremely protected organ and not easy to localize, which makes this procedure a great microsurgical challenge. Here we report a new microsurgical technique to identify, localize and dissect ZKM in adult zebrafish using a new approach. The potential advantages of this technique are summarized here: it allows purity of the sample, which is critical for performing flow cytometry analysis and/or cell number count; it enables visualization of the ZKM without a parenchimal incision, which simplifies the further dissection; the learning curve is short, requiring only basic microsurgical skills, and it is reliable and highly reproducible. To further characterize the kidney marrow cells obtained by this technique, we performed histology, flow cytometry, cytospin experiments and cell counts.
Abstract: INTRODUCTION AND OBJECTIVE: To analyze the outcome, complications and functional results in patients undergoing bladder substitution with the Studer continent urinary pouch. MATERIALS AND METHODS: At our Clinic, between January 2005 and December 2006, 20 male patients underwent a radical cystoprostatectomy followed by the Studer orthotopic bladder substitution. RESULTS: The transitional cell carcinoma was found to be the most frequent histopathological type. The distribution by grade and pathological stage showed all were high grade infiltrating tumors localized in the bladder. We observed 3 patients with neobladder-unrelated complications: one patient with a wound infection and 2 patients with a prolonged ileus. CONCLUSION: In conclusion, our results with urinary diversion are promising in patients recquiring a radical cystoprostatectomy. We believe that the Studer's orthotopic neobladder is an excellent alternative for patients suffering a radical cystectomy and offers a sufficient protection of the upper urinary tract with a low complication rate, good voiding function and continence (Tab. 1, Ref. 25). Full Text (Free, PDF) www.bmj.sk.
Abstract: PURPOSE: Patients with a surgically reduced renal mass are at increased risk for progressive renal failure, which often requires renal replacement therapy or kidney transplantation. We investigated the effects of simvastatin supplementation on uremia enhanced atherosclerosis and vascular calcification in apoE(-/-) (apolipoprotein E deficient) mice (Charles Rivers Laboratories, Wilmington, Massachusetts) with or without superimposed chronic kidney disease. MATERIALS AND METHODS: The mice were randomly assigned to 4 groups, including 2 groups with normal renal function (simvastatin vs control in 13 mice) and the other 2 with surgically created chronic kidney disease (simvastatin vs control in 18). Simvastatin (100 mg/kg) was administered by daily oral gavage for 4 weeks. RESULTS: Simvastatin treatment did not prevent uremia accelerated atherosclerosis in chronic kidney disease apoE(-/-) mice, nor did it retard atherosclerosis progression in control nonchronic kidney disease mice. However, aortic plaques in simvastatin treated chronic kidney disease mice showed significantly less calcification than those in controls with chronic kidney disease (p <0.03). In addition, the increase of aortic nitrotyrosine staining in mice with chronic kidney disease was prevented by simvastatin treatment (p <0.02). Serum total cholesterol was increased to a similar extent in the 2 chronic kidney disease groups compared with that in the nonchronic kidney disease groups. The beneficial effect of simvastatin on uremia enhanced vascular calcification in apoE(-/-) mice with chronic kidney disease was observed despite the absence of changes in uremia accelerated atherosclerosis progression, serum total cholesterol levels or osteopontin and alkaline phosphatase expression. CONCLUSIONS: Our observation opens the possibility of a cholesterol independent action of statins on vascular calcification via a decrease in oxidative stress.
Abstract: BACKGROUND: In chronic kidney disease (CKD) patients, the intake of calcium-based phosphate binders is associated with a marked progression of coronary artery and aortic calcification, in contrast to patients receiving calcium-free phosphate binders. The aim of this study was to reexamine the role of calcium carbonate in vascular calcification and to analyse its effect on aortic calcification-related gene expression in chronic renal failure (CRF). METHODS: Mice deficient in apolipoprotein E underwent either sham operation or subtotal nephrectomy to create CRF. They were then randomly assigned to one of the three following groups: a control non-CRF group and a CRF group fed on standard diet, and a CRF group fed on calcium carbonate enriched diet, for a period of 8 weeks. Aortic atherosclerotic plaque and calcification were evaluated using quantitative morphologic image processing. Aortic gene and protein expression was examined using immunohistochemistry and Q-PCR methods. RESULTS: Calcium carbonate supplementation was effective in decreasing serum phosphorus but was associated with a higher serum calcium concentration. Compared with standard diet, calcium carbonate enriched diet unexpectedly induced a significant decrease of both plaque (p < 0.05) and non-plaque-associated calcification surface (p < 0.05) in CRF mice. It also increased osteopontin (OPN) protein expression in atherosclerotic lesion areas of aortic root. There was also a numerical increase in OPN and osteoprotegerin gene expression in total thoracic aorta but the difference did not reach the level of significance. Finally, calcium carbonate did not change the severity of atherosclerotic lesions. CONCLUSION: In this experimental model of CRF, calcium carbonate supplementation did not accelerate but instead decreased vascular calcification. If our observation can be extrapolated to humans, it appears to question the contention that calcium carbonate supplementation, at least when given in moderate amounts, necessarily enhances vascular calcification. It is also compatible with the hypothesis of a preponderant role of phosphorus over that of calcium in promoting vascular calcification in CRF.
Abstract: OBJECTIVES: The aim of this report is to present our 30 years experience with various types of urinary diversions, in particular the Bricker and Studer techniques for the management of muscle invasive bladder cancer at our institution. Perioperative, early and late complications are also evaluated. MATERIAL AND METHODS: Between 1977 and 2007, 186 male and 15 female patients underwent combined radical cystectomy, pelvic lymphadenectomy and urinary diversion. In two subgroups of patients we evaluated the complications, divided as early and late, and subdivided as those related or unrelated to the neobladder. Mean follow up time was 28 months (range 12-60 months). RESULTS: Two main types of urinary diversion were performed: the ileal conduit diversion using a technique previously described by Bricker and the ileal neobladder diversion using a technique previously described by a Studer. The ages at surgery ranged from 40 to 82 years with a mean age of 60 years. Histopathologically, transitional cell carcinoma was the most common tumor cell type (93,7%), followed by difuse papilomatosis (5.5%) and adenocarcinoma (0.7%). The pathological tumor stage was pT1 (4.7%), pT2 (31.4%), pT3 (50.3 %) and pT4a (13,3%). Histological evidence of regional lymph node involvement was seen in 25% of the cases. From 52 patients from the Studer subgroup perioperative complications were found in 16 patients (30.7%). Specific early complications directly related to the neobladder occurred in 14 (26.9%) patients. Prolonged ileus in 2 patient (3.8%), ureteral leakage in 9 patients (17.3%), mucous buildup within the diversion in 3 patients (5.7%). Late complications occurred in 10 patients (19.2%): retention of the urine in 4 patients (7.6%) (stricture of the urethra-pouch anastomosis in one 1 patient) and to big reservoir in 3 patients. One patient (1.9%) developed prolonged metabolic acidosis. Stone formation was observed in one patient, two years postoperatively. Unilateral hydroureteronephrosis was observed in 2 patients whereas bilateral hydroureteronephrosis was observed in one patients at one year postoperatively. Perioperative and late complications were similar in the 32 patients from the Bricker subgroup. CONCLUSION: We show that our results with urinary diversion are promising in patients requiring radical cystoprostatectomy. The two methods preferred in our institution offer a sufficient protection of the upper urinary tract with a low complication rate, good voiding function and continence.
Abstract: The occurrence of malignancies is a well-known serious complication after organ transplantation. Despite the fact that many factors may be involved, the pathogenesis is still unclear. The aim of the present study was to examine the incidence and clinical characteristics of de novo malignancies that arise after renal transplantation over a 13-year experience in a single center in the Balkan Peninsula. During this period, 185 renal transplantations (139 living related and 46 cadaveric) were followed in our department. Overall, 19 malignancies (9.78%) were observed in 15 patients (7.8%). The mean age of these patients was 45 years (range, 21-53 years). Ten patients (55%) developed skin cancers: 8 squamous and 2 basal cell. Kaposi's sarcomas were found in 3 patients (16.6%, 1 visceral form). We also detected 1 breast cancer, 1 seminoma, 1 colon cancer, 1 urogenital-transitional cell-like cancer, 1 renal cell carcinoma, 1 plasmacytoma, and 1 retroperitoneal sarcoma after an ABO incompatible transplantation. All cancers were de novo malignancies that presented at a mean time of 21 months (range, 2-52 months) after surgery. In conclusion, the incidence of malignancy in the present series was similar to that reported elsewhere. The predominance of skin cancers was understandable bearing in mind the sunshine. The appearance of skin malignancies in our group of patients was earlier, more severe, and multiple sites. No cases of posttransplantation lymphoproliferative disorders were observed. Careful clinical examination and long-term screening protocols are needed for early detection and treatment of this life-threatening complication among the transplant population.
Abstract: Introduction. Entrapment or strangulation of the penis is a rare emergency situation that can lead to a wide range of vascular and mechanical injuries. Aim. The aim of this article is to present our experience dealing with penile strangulation. A review of the literature is also summarized in this report. Current treatment options and outcomes are also evaluated. Methods. We performed a computerized MEDLINE search followed by a manual bibliographic review of cross-references. These reports were analyzed and the important findings summarized. Results. Penile strangulation has been first time reported in 1755. Since that time, sporadic reports have appeared in the literature describing a variety of foreign bodies on the penis that have in common only the property of circularity. We noted motives, types of objects, types of strangulation, symptomatology, trauma grades, diagnoses, including psychological involvement, as well as possible treatment options. Furthermore, two cases of penile strangulation from our clinical practice are presented involving different degrees of vascular insult leading to different pathogenesis, clinical presentation, and surgical approach. Conclusion. Penile strangulation is an unusual clinical condition and the consequences can be severe. Penile strangulation could lead to different degrees of vascular obstruction. Consequently, several clinical syndromes can occur: from mild nonsignificant vascular obstruction that resolves after decompression to severe gangrene of the penis accompanied with impaired renal function. The most common motive associated with foreign bodies on the penis is sexual or erotic in nature. The choice of method for removal depends upon type, size, incarceration time, trauma grade, and availability of the equipment. Prompt diagnosis and early treatment are essential to avoid the potential complications of ischemic necrosis and autoamputation.
Abstract: Cardiovascular disease (CVD) is the most frequent cause of morbidity and mortality in chronic renal failure (CRF) patients. Accelerated calcifying atherosclerosis, medial calcification, and valvular calcification are hallmarks of CVD in the dialysis population. The mechanisms by which uraemia promotes vascular calcification and the relationship between arterial wall calcification and atherosclerosis are poorly understood. We surgically induced CRF in apolipoprotein E knockout (apoE-/-) mice to study a possible acceleration of aortic atherosclerosis, the degree and type of vascular calcification as well as factors involved in the calcification process. Finally we investigated appropriate treatment measures. Atherosclerotic lesions in the thoracic aorta were significantly larger in uraemic apoE-/- mice than in non-uraemic controls. The relative proportion of the calcified area to the total surface area of both atherosclerotic lesions and lesion-free vascular tissue was increased in the aortic root of uraemic apoE-/- mice when compared with controls. The accelerated atherosclerosis was associated with an increase in aortic nitrotyrosine expression, indicating enhanced oxidative stress, and an increase in plaque collagen content, indicating changes in plaque composition. N-acetylcysteine (NAC) treatment slowed the rapid progression of atherosclerotic lesions and reversed the increase in plaque collagen content compared with placebo treatment. NAC-treatment also reduced nitrotyrosine expression in uremic apoE-/- mice whereas the degree of macrophage infiltration was unchanged. Sevelamer treatment delayed not only vascular calcification but also atherosclerotic lesion progresssion in uraemic apoE-/- mice. These treatment effects also were associated with diminished oxidative stress and were independent of cholesterol lowering. We anticipate that this experimental model will prove to be useful to test other treatment strategies aimed at decreasing the accelerated atherosclerosis and arterial calcification of the uraemic state. Key words: atherosclerosis, vascular calcification, chronic renal failure, oxidative stress, mouse.
Abstract: BACKGROUND: The novel phosphate binder sevelamer has been shown to prevent the progression of aortic and coronary calcification in uremic patients. Whether it also decreases the progression of atheromatous plaques is unknown. The aim of our study was to examine the effect of sevelamer administration on the development of atherosclerosis and aortic calcification in the uremic apolipoprotein E-deficient mouse as an established model of accelerated atherosclerosis. METHODS AND RESULTS: Female mice were randomly assigned to 4 groups: 2 groups of nonuremic mice (sevelamer versus control) and 2 groups of uremic mice (sevelamer versus control). Sevelamer was given at 3% with chow. The increases in serum phosphorus concentration and calcium-phosphorus product observed in uremic control mice were prevented by sevelamer. Serum total cholesterol was increased in the 2 uremic mouse groups and remained unchanged in response to sevelamer. After 8 weeks of sevelamer treatment, uremic mice exhibited a significantly lower degree of atherosclerosis (P<0.001) and vascular calcification than uremic control mice. Of interest, sevelamer exerted an effect on both intima and media calcification (P=0.005) in uremic mice. Among possible mechanisms involved, we found no evidence for the modulation by sevelamer of inflammation or selected uremic toxins. In contrast, nitrotyrosine staining as a measure of oxidative damage was significantly decreased in response to sevelamer treatment in control and uremic mice (P<0.005). CONCLUSIONS: Sevelamer delays not only vascular calcification but also atherosclerotic lesion progression in uremic apolipoprotein E-deficient mice. It opens the possibility of a cholesterol-independent action of sevelamer on atheroma formation via effects on mineral metabolism, oxidative stress, or both.
Abstract: BACKGROUND: Whether a general reduction in salt intake reduces or actually enhances cardiovascular mortality in man remains an issue of controversy. Low sodium diets may lead to adverse side effects by stimulating the renin-angiotensin and sympathetic nervous systems. The present study was designed to investigate the effects of low dietary salt on atherosclerotic lesion progression in apolipoprotein E deficient (apoE(-/-)) mice. METHODS AND RESULTS: We fed 7-week-old apoE(-/-) mice on low (0.036% NaCl; n=28) or regular (0.64% NaCl; n=26) salt diets for 16 weeks. At the age of 23 weeks, the cross-section surface area of atherosclerotic plaques was measured in aortic root and thoracic aorta. Serum total cholesterol, triglycerides, plasma angiotensin levels and urinary protein/creatinine concentrations were assessed. Exposure to low salt caused significant increases in atherosclerotic lesion surface area in thoracic aorta, but did not alter lesion area in aortic root. Low-salt mice also had higher serum total cholesterol and higher plasma angiotensin II (ANG-II) concentrations. Atherosclerotic lesion area was correlated with ANG-II levels in low-salt but not in regular-salt animals, and with total cholesterol concentration in all mice. Mean arterial pressure was comparable in both groups. CONCLUSIONS: Dietary salt restriction accelerated atherosclerotic lesion formation in apoE(-/-) mice through a mechanism that is probably related to ANG-II formation. Whether these findings are relevant to human cardiovascular disease remains to be evaluated.
Abstract: Chronic renal failure (CRF) favors the development of atherosclerosis and excessive calcification of atheromatous lesions. CRF was induced in apolipoprotein E knockout (apoE(-/-)) mice to study (1) a possible acceleration of aortic atherosclerosis, (2) the degree and type of vascular calcification, and (3) factors involved in the calcification process. For creating CRF, 8-wk-old apolipoprotein E gene knockout (apoE(-/-)) mice underwent partial kidney ablation. Control animals underwent sham operation. Aortic atherosclerotic plaques and calcification were evaluated using quantitative morphologic image processing. At 6 wk after nephrectomy, CRF mice had significantly higher serum urea, cholesterol, and triglyceride concentrations than non-CRF controls. The serum levels of advanced oxidation protein products were elevated in the uremic group and were correlated with serum urea levels. Atherosclerotic lesions in thoracic aorta were significantly larger in uremic apoE(-/-) mice than in nonuremic controls. The relative proportion of calcified area to total surface area of both atherosclerotic lesions and lesion-free vascular tissue was increased in aortic root of uremic apoE(-/-) mice when compared with controls. The calcium deposits were made of hydroxyapatite and calcite crystals. In addition, plaques from uremic animals showed a significant increase in collagen content, whereas the degree of macrophage infiltration was comparable in both groups. There was no difference in mean arterial BP. These findings demonstrate that CRF aggravates atherosclerosis in apoE(-/-) mice. Moreover, CRF enhances arterial calcification at both atheromatous intimal sites and atheroma-free medial sites. We anticipate that this experimental model will be useful to test treatment strategies aimed at decreasing the accelerated atherosclerosis and arterial calcification in uremia.
Abstract: BACKGROUND: Cardiovascular disease is the most frequent cause of mortality in chronic renal failure (CRF). Therefore, it is important to identify appropriate treatment measures. The antioxidant N-acetylcysteine (NAC) has been shown to reduce cardiovascular events in hemodialysis patients. Here we examine a possible direct effect of NAC supplementation on uremia-enhanced atherosclerosis in apolipoprotein E-deficient (apoE(-/-)) mice. METHODS: Uremia was induced surgically in 8-week-old female apoE(-/-) mice. Two weeks after creation of CRF mice were randomized to receive either NAC (daily oral gavage with 200 mg/kg for 8 weeks) or placebo. They were compared to a control group of sham-operated apoE(-/-) mice receiving placebo. After 8 weeks of treatment, the mice were sacrificed, and the cross-section surface area of atherosclerotic plaques was measured in aortic root and descending aorta. RESULTS: At 10 weeks following surgery, atherosclerotic lesions were significantly larger in uremic apoE(-/-) mice than in nonuremic controls. This accelerated atherosclerosis was associated with an increase in aortic nitrotyrosine expression and collagen plaque content. NAC treatment inhibited the progression of atherosclerotic lesions and plaque collagen content compared with placebo treatment. In addition, plaques from NAC-treated uremic animals showed a significant decrease in nitrotyrosine expression whereas the degree of macrophage infiltration was comparable in both uremic groups. There was no difference in mean arterial blood pressure between the three groups. CONCLUSION: We show for the first time that the antioxidant NAC is capable of reducing atheroma progression, in an animal model of uremia-enhanced atherosclerosis, probably via a decrease in oxidative stress.
