Abstract: OBJECTIVES: Echocardiography is a fundamental tool in the diagnosis of acute left ventricular heart failure (aLVHF). However, a consultative exam is not routinely available in every emergency department (ED). The authors investigated the diagnostic performance of emergency Doppler echocardiography (EDecho) performed by emergency physicians (EPs) for the diagnosis of aLVHF in patients with acute dyspnea. METHODS: A convenience sample of acute dyspneic patients was evaluated. For each patient, the Boston criteria score for heart failure was calculated, and N-terminal prohormone brain natriuretic peptide (NT-proBNP) and EDecho were contemporaneously performed. Four investigators, after a limited echocardiography course, performed EDechos and evaluated for a "restrictive" pattern on pulsed Doppler analysis of mitral inflow and reduced left ventricular (LV) ejection fraction. The final diagnosis, established after reviewing all patient clinical data except NT-proBNP and EDecho results, served as the criterion standard. RESULTS: Among 145 patients, 64 (44%) were diagnosed with aLVHF. The median time needed to perform EDecho was 4 minutes. Pulsed Doppler analysis was feasible in 125 patients (84%). The restrictive pattern was more sensitive (82%) and specific (90%) than reduced LV ejection fraction and more specific than the Boston criteria and NT-proBNP for the diagnosis of aLVHF. Considering noninterpretable values of the restrictive pattern and uncertain values ("gray areas") of Boston criteria (4 < Boston criteria score < 7) and of NT-proBNP (300 < NT-proBNP < 2,200 pg/mL) as false results, the accuracy of the restrictive pattern in the overall population was 75%, compared with accuracy of 49% for both NT-proBNP and Boston criteria. CONCLUSIONS: EDecho, particularly pulsed Doppler analysis of mitral inflow, is a rapid and accurate diagnostic tool in the evaluation of patients with acute dyspnea.
Abstract: Background: The absence of a rapidly available and sensitive diagnostic test represents an important limitation in the triage of patients with suspected stroke. Objectives: The aim of the present study was to investigate the triage accuracy of a novel test that measures blood-borne biomarkers (triage stroke panel, TSP) and to compare its accuracy with that of the Cincinnati Prehospital Stroke Scale (CPSS). Methods: Consecutive patients with suspected stroke presenting to the Emergency Departments of three Italian hospitals underwent triage by a trained nurse according to the CPSS and had blood drawn for TSP testing. The TSP simultaneously measures four markers (B-type natriuretic peptide, D-dimer, matrix metalloproteinase-9, and S100beta) presenting a single composite result, the Multimarker Index (MMX). Stroke diagnosis was established by an expert committee blinded to MMX and CPSS results. Results: There were 155 patients enrolled, 87 (56%) of whom had a final diagnosis of stroke. The area under the receiver operating characteristic (ROC) curve for CPSS was 0.77 (95% confidence interval [CI] 0.70-0.84) and that of MMX was 0.74 (95% CI 0.66-0.82) (p = 0.285). Thus, both tests, when used alone, failed to recognize approximately 25% of strokes. The area under the ROC curve of the combination of the two tests (0.86, 95% CI 0.79-0.91) was significantly greater than that of either single test (p = 0.01 vs. CPSS and p < 0.001 vs. TSP). Conclusions: In an emergency care setting, a panel test using multiple biochemical markers showed triage accuracy similar to that of CPSS. Further studies are needed before biomarkers can be introduced in the clinical work-up of patients with suspected stroke.
Abstract: OBJECTIVE: To investigate the prognostic value of electrocardiography (ECG) alone or in combination with echocardiography in patients with acute pulmonary embolism and normal blood pressure. METHODS: Consecutive adult patients presenting to the emergency department at Azienda Ospedaliero-Universitaria Careggi with the first episode of pulmonary embolism were included. Patients with systolic blood pressure less than 100 mm Hg were excluded. ECG and echocardiography were performed within 1 hour from diagnosis and evaluated in a blinded fashion. Right ventricular strain was diagnosed in the presence of one or more of the following ECG findings: complete or incomplete right ventricular branch block, S1Q3T3, and negative T wave in V1-V4. The main outcome measurement was clinical deterioration or death during in-hospital stay. The association of variables with the main outcome was evaluated by multivariate Cox survival analysis. RESULTS: A total of 386 patients with proved pulmonary embolism were included in the study; 201 patients (52%) had right ventricular dysfunction according to echocardiography, and 130 patients (34%) showed right ventricular strain. Twenty-three patients (6%) had clinical deterioration or died. At multivariate survival analysis, right ventricular strain was associated with adverse outcome (hazard ratio 2.58; 95% confidence interval, 1.05-6.36) independently of echocardiographic findings. Patients with both right ventricular strain and right ventricular dysfunction (26%) showed an 8-fold elevated risk of adverse outcome (hazard ratio 8.47; 95% confidence interval, 2.43-29.47). CONCLUSION: Right ventricular strain pattern on ECG is associated with adverse short-term outcome and adds incremental prognostic value to echocardiographic evidence of right ventricular dysfunction in patients with acute pulmonary embolism and normal blood pressure.
Abstract: BACKGROUND: Patients with chest pain (CP) and nondiagnostic ECG represent heterogeneous population in whom the evaluation of coronary risk factors including metabolic syndrome (MetS) and diabetes mellitus (DM) might improve risk stratification. METHODS: We enrolled 798 consecutive CP patients; 14% presented with MetS and 10% with DM; the remaining 76% presented with other coronary risk profiles (others). All patients underwent maximal exercise tolerance test (ETT) and myocardial perfusion imaging (exercise-MPI). Those with positive testing underwent angiography, whereas the remaining patients were discharged and later followed up. Primary end-point was a composite of coronary stenoses greater than or equal to 50% documented by angiography or coronary events at follow-up. RESULTS: Patients with MetS or DM had significantly lower survival free from end-point than those patients without (P<0.001). Exercise-MPI showed high negative predictive value in MetS, DM, and others (>96%); however, positive predictive value was 69, 74, and 52%, respectively (P<0.05). ETT alone showed negative predictive value (88%) which was significantly lower than exercise-MPI (98%), (MetS vs. others: P<0.001, and DM vs. others: P=0.05). The area under the receiver-operating characteristic curves obtained from the multivariate model includes clinical data alone, clinical data and ETT results, or clinical data and exercise-MPI results increase progressively. CONCLUSION: A nuclear scan strategy in special populations, including CP patients with MetS or DM, is a valuable tool for risk stratification and adds incremental prognostic value over clinical and ETT values.
Abstract: OBJECTIVES: To evaluate the accuracy and safety of an emergency duplex ultrasound (EDUS) evaluation performed by emergency physicians in the emergency department. METHODS: Consecutive adult patients suspected of having their first episode of deep vein thrombosis (DVT) presenting to the emergency department were included in the study. All examinations were performed by emergency physicians trained with a 30-hour ultrasound course. Based on EDUS findings, patients were classified into one of three groups: normal, abnormal, and uncertain. Patients with abnormal and uncertain findings were initially treated as having a DVT. Patients with normal EDUS findings were discharged from the emergency department without anticoagulant therapy. A formal duplex ultrasound evaluation was repeated by a radiologist in all patients within 24-48 hours. Patients with normal findings on duplex ultrasound evaluation were followed up for symptomatic venous thromboembolism for up to one month. RESULTS: A total of 399 patients were studied. The EDUS findings were normal in 301 (75%), abnormal in 90 (23%), and uncertain in eight (2%). All abnormal test results were confirmed by the formal duplex ultrasound evaluation, and three patients (0.8%) with uncertain findings on EDUS examination were subsequently diagnosed as having a distal DVT (positive predictive value, 95% [95% confidence interval, 92% to 95%]; negative predictive value, 100% [95% confidence interval = 99% to 100%]). No patients with normal findings on EDUS examination died or experienced venous thromboembolism at the one-month follow-up. CONCLUSIONS: EDUS examination yielded a high negative predictive value and good positive predictive value, allowing rapid discharge and avoiding improper anticoagulant treatment.
Abstract: Echocardiographic right ventricular (RV) dysfunction is a well-established prognostic indicator in patients with acute pulmonary embolism. However, the possibility of implementing a rapid and effective triage with biohumoral markers such as brain natriuretic peptide (BNP) may be of value. Sixty-one patients with a first documented episode of acute pulmonary embolism without shock and previous left ventricular dysfunction were prospectively studied. All patients underwent echocardiography and rapid BNP testing on admission. Patients were followed up for in-hospital death, progression to shock, and nonfatal pulmonary embolism recurrence. Overall, 35 patients (57%) had echocardiographic evidence of RV dysfunction on admission, and its prevalence increased progressively with increasing levels of BNP. A BNP level <85 pg/ml was highly accurate in excluding RV dysfunction. No patient in the lower tertile of BNP values (1.1 to 85.0 pg/ml) had RV dysfunction, compared with 75% in the middle tertile (88.7 to 487.0 pg/ml) and 100% in the upper tertile (527 to 1,300 pg/ml). Overall, 11 patients (18%), belonging to the upper tertile, progressed to shock during admission, 4 of whom died. The association of RV dysfunction with a BNP level in the upper tertile (>or=527 pg/ml) showed incremental prognostic value over RV dysfunction alone (in-hospital death and progression to shock were 55% and 31%, respectively). In the present study, BNP represented a powerful predictor of in-hospital clinical deterioration, with substantial incremental prognostic value over echocardiography alone.
Abstract: OBJECTIVE: Sepsis is a frequent and often lethal condition. Rapid identification and aggressive therapy in the emergency department (ED) are essential for outcome. Several indexes were found to be significantly related to short-term clinical outcome, but only bedside, rapidly available tests are thought to be useful in the ED. To define the prevalence and mortality of patients with severe sepsis presenting to the ED of a tertiary care hospital in Italy, we furthermore investigated the ability of bedside, non-invasive prognostic indexes to identify patients with adverse short-term clinical outcome. METHODS: All patients admitted to the ED with a diagnosis of severe sepsis or septic shock were included. Retrospective data were collected by a dedicated software program using predefined searching criteria including clinical data, vital sign parameters, sepsis-related organ failure assessment (SOFA) score, and blood tests. The relationship between prognostic indexes and 24-h or 28-day mortality was evaluated by multivariate logistic regression analysis. RESULTS: Ninety patients were enrolled from June 2004 to June 2005 (0.2% of all incoming patients to ED and 0.7% of all critical patients). Mean age was 77 +/- 15 years, 54.4% were women. During follow-up (28 days) 46 patients died (51.1%), 21 patients (23.3%) within 24 h. At multivariate analyses, age >80 (odds ratio [OR] 4.10; 95% confidence intervals [CI] 1.39-11.90, p = 0.01), serum lactate >5 mmol/l (OR 3.40; 95% CI 1.21-9.60, p = 0.02) and acute renal failure (OR 18.90; 95% CI 1.80-200, p = 0.02) were independent predictors of 28-day mortality. CONCLUSIONS: Among critical patients admitted to an Italian ED, those with severe sepsis/septic shock represent about 1%, with a very high mortality rate. Bedside non-invasive prognostic indexes are able to identify with high accuracy patients with adverse short-term clinical outcome.
Abstract: BACKGROUND: The degree of pulmonary hypertension in healthy subjects exposed to acute hypobaric hypoxia at high altitude was found to be related to increased plasma endothelin (ET)-1. The aim of the present study was to investigate the effects of ET-1 antagonism on pulmonary hypertension, renal water, and sodium balance under acute and prolonged exposure to high-altitude-associated hypoxia. METHODS AND RESULTS: In a double-blind fashion, healthy volunteers were randomly assigned to receive bosentan (62.5 mg for 1 day and 125 mg for the following 2 days; n=10) or placebo (n=10) at sea level and after rapid ascent to high altitude (4559 m). At sea level, bosentan did not induce any significant changes in hemodynamic or renal parameters. At altitude, bosentan induced a significant reduction of systolic pulmonary artery pressure (21+/-7 versus 31+/-7 mm Hg, P<0.03) and a mild increase in arterial oxygen saturation versus placebo after just 1 day of treatment. However, both urinary volume and free water clearance (H2OCl/glomerular filtration rate) were significantly reduced versus placebo after 2 days of ET-1 antagonism (1100+/-200 versus 1610+/-590 mL; -6.7+/-3.5 versus -1.8+/-4.8 mL/min, P<0.05 versus placebo for both). Sodium clearance and segmental tubular function were not significantly affected by bosentan administration. CONCLUSIONS: The present results indicate that the early beneficial effect of ET-1 antagonism on pulmonary blood pressure is followed by an impairment in volume adaptation. These findings must be considered for the prevention and treatment of acute mountain sickness.
Abstract: BACKGROUND: In patients with acute pulmonary embolism, right ventricular dysfunction (RVD) on hospital admission is a predictor of adverse short-term clinical outcome. The aim of this study was to evaluate the prognostic value of RVD persistence at hospital discharge with regard to the likelihood of recurrent venous thromboembolism (VTE). METHODS: Echocardiography was used to assess RVD on admission and before hospital discharge in 301 consecutive patients with the first episode of acute pulmonary embolism occurring from January 1998 through July 2004. Right ventricular dysfunction was diagnosed in the presence of 1 or more of the following: right ventricular dilation (without hypertrophy), paradoxical septal systolic motion, and Doppler evidence of pulmonary hypertension. Patients were followed up at 2, 6, and 12 months and yearly thereafter. The primary end point was symptomatic, recurrent fatal or nonfatal VTE. RESULTS: Patients were categorized as those (1) without RVD (155 patients [51.5%]), (2) with RVD regression (RVD on admission but not at discharge; 87 patients [28.9%]), and (3) with persistent RVD (RVD on admission and at discharge; 59 patients [19.6%]). After a mean +/- SD of 3.1 +/- 2.7 years, patients with RVD persistence showed an increased risk of recurrent VTE (14 patients, 9.2% patient-years) compared with those without RVD (15 patients, 3.1% patient-years) or RVD regression (3 patients, 1.1% patient-years) (P = .001). Six of 8 deaths related to pulmonary embolism occurred in patients with RVD persistence. At multivariate analysis, adjusted by anticoagulant treatment duration, RVD persistence was an independent predictor of recurrent VTE (hazard ratio, 3.79; P<.001). CONCLUSION: Persistent RVD at hospital discharge after an acute pulmonary embolism is associated with recurrent VTE.
Abstract: BACKGROUND: The management of patients with acute coronary syndromes without ST-segment elevation (NSTEACS) in a chest pain unit (CPU) should represent a cost-effective advantage over conventional management in a coronary care unit (CCU). However, the safety and advantages of this approach are still unresolved. MATERIAL/METHODS: Outcomes and management costs were evaluated in patients with NSTEACS with intermediate-high TIMI risk scores (> or =3) randomized to receive management in a CPU or a CCU. Coronary events (CEs: angina, myocardial infarction, and death), revascularization, and resource utilization were compared between the two groups during hospital stay and at 6 months. RESULTS: Two hundred and ten patients were enrolled, 104 in the CPU and 106 in the CCU group. CEs were similar in both groups both during hospitalization (28% vs. 26%, respectively) and at 6 months (17% vs. 16%). Angiography was performed in 67% vs. 75%; CPU patients less frequently underwent revascularization (53% vs. 76%; p=0.002). In-hospital duration was similar in both groups (7.5 days vs. 5.7 days). CPU patients had a 22% reduction in overall hospitalization costs compared with conventional management (9,913 vs. 12,056 euros/patient; p=0.01). This gain was particularly relevant (29%) when patients with TIMI risk score < or =4 were considered (10,599 vs. 13,699 euros/patient; p=0.004). CONCLUSIONS: CPU care of NSTEACS is a safe and cost-effective alternative to conventional CCU management, particularly appealing with regard to patients presenting with intermediate TIMI risk score (< or =4) in whom CPU management could optimize the use of cath-lab facilities and dedicated cardiologists.
Abstract: OBJECTIVES: To characterise the efficiency of the cardiopulmonary baroreflex system in the early phase of heart failure and its relation to limitation of physical activity. DESIGN: Forearm blood flow (venous occlusion plethysmography), vascular resistance, and central venous pressure (CVP), estimated from an antecubital vein, were measured in the supine position at baseline and 15 minutes after application of lower body negative pressure at -7 and -14 mm Hg (receptor downloading) or leg raising (receptor loading). SUBJECTS: Heart failure patients without limitation (NYHA class I; n = 18) or with slight limitation of physical activity (NYHA class II; n = 13), and 11 healthy controls. RESULTS: The efficiency of the cardiopulmonary baroreflex function, expressed by the slope of the relation between CVP changes and the corresponding changes of calculated forearm vascular resistance (gain), was reduced both in NYHA class I patients (mean (SD) -1.99 (0.83) v -2.78 (0.66) in controls; p < 0.05) and NYHA class II patients (-1.29 (0.5); p<0.001 v controls). However, change in peripheral vascular resistance during preload increase was similar in controls (-3.3 (0.9) units) and in NYHA class I patients (-3.3 (2.1) units; NS v controls), and was significantly reduced only in NYHA class II patients (-1.6 (1.3) units, p < 0.03 v controls). The gain in the cardiopulmonary reflex was related to the distance walked during the six minute corridor test. CONCLUSIONS: A reduced tonic efficacy of the cardiopulmonary reflex system is already detectable in the early phase of heart failure, the impairment in acute response to preload increase being detectable only in symptomatic patients.
Abstract: Mechanical factors play a key role in activation of cardiac growth factor response in hemodynamic overload, and both cooperate in myocardial remodeling. The present study was performed to investigate whether a different growth factor response is activated in the right and left ventricles in aortocaval fistula and its effects on regional myocardial adaptation. Relations between regional growth factor expression (angiotensin II, insulin-like growth factor-I, and endothelin-1), myocyte shape changes, and collagen deposition were investigated at mRNA and peptide levels in adult pigs after the creation of an aortocaval fistula distal to the renal arteries (n=15) and in sham-operated animals (n=15). The role of angiotensin II was investigated by the administration of angiotensin-converting enzyme inhibitor or angiotensin II receptor antagonist. In the left ventricle, pure volume overload was accompanied by persistent increase of insulin-like growth factor-I mRNA expression, peptide concentration (2.2-fold versus sham at 3 months, P<0.05), and significant increase of myocyte length (+29% at 3 months, P<0.05). Conversely, the mixed pressure-volume overload faced by the right ventricle resulted in significant regional overexpression of all growth factors investigated (angiotensin II, insulin-like growth factor-I, and endothelin-1), with corresponding increase of myocyte diameter and length and collagen deposition (+117% at 3 months). Collagen accumulation in the right ventricle as well as the increase in right ventricular end-diastolic pressure at the 3-month observation were inhibited by angiotensin II antagonism. The left and right ventricles respond differently to aortocaval fistula, and local growth factor expression is closely related to the regional myocardial adaptation.
Abstract: OBJECTIVE: To investigate whether an inflammatory response occurs in patients undergoing infrarenal aortic abdominal aneurysm repair, the localization and timing (ischemia and/or reperfusion) of this activation, and finally whether it affects postoperative pulmonary function. DESIGN: Prospective, observational study. SETTING: Academic referral center in Italy. PATIENTS: We included 12 patients undergoing infrarenal aortic abdominal aneurysm repair and 12 patients undergoing major abdominal surgery. INTERVENTIONS: Timed measurement of gene activation (angiotensinogen, angiotensin type 1 receptor, angiotensin-converting enzyme, and interleukin-6 genes) in muscle biopsies by reverse transcriptase-polymerase chain reaction (RT-PCR), and prospective assessment of interleukin-6 plasma concentration and pulmonary function (Pao2/FIO2 and Pao2/PAO2 ratios). MEASUREMENTS AND MAIN RESULTS: After 30 mins of aortic clamping, angiotensinogen, angiotensin type 1 receptor, angiotensin-converting enzyme, and interleukin-6 genes were all overexpressed at RT-PCR studies in quadriceps muscle of patients undergoing aortic abdominal aneurysm repair, and the overexpression persisted after reperfusion. In situ hybridization and immunohistochemistry revealed that the inflammatory response was localized in endothelial cells. A significant increase in plasma interleukin-6 concentrations was then detectable at 6 and 12 hrs after reperfusion in aortic abdominal aneurysm surgery compared with patients undergoing abdominal surgery (p < .05). The increase in interleukin-6 plasma concentration was then followed (12 and 24 hrs after surgery) by a significant reduction of Pao2/ FIO2 and Pao2/PAO2 ratios (p < .05 vs. abdominal surgery). CONCLUSIONS: The present study shows that a) during aortic surgery, the genes for interleukin-6 and for the components of the local renin-angiotensin system (angiotensinogen, angiotensin-converting enzyme, and angiotensin type 1 receptor subtype) are activated early in the ischemic muscle, and activation persists during reperfusion; b) interleukin-6 plasma concentration increases only in patients with tissue ischemia (aortic abdominal aneurysm), whereas no changes are detectable in patients with abdominal surgery; and finally c) the occurrence of systemic inflammatory reaction with increased interleukin-6 plasma concentrations is followed by impaired pulmonary function.
Abstract: Abundant evidence showed that angiotensin-converting enzyme (ACE)-inhibitors reduce long-term cardiovascular morbidity and mortality rates in patients with heart failure and myocardial infarction. More recent studies revealed clinical benefits also in hypertensive patients with comorbidity and lead to an extension of clinical indications. Indeed in patients with severe hypertension differences between drugs are hardly detectable because the risk reduction is mainly related to the control of blood pressure values independent of the type of therapy. Conversely in the presence of comorbid conditions, especially in diabetics, the association of ACE-inhibitors with antihypertensive treatments proved its efficacy in reducing cardiovascular morbidity and mortality so that the role of mechanisms extending beyond blood pressure reduction can be postulated.
Abstract: Renal endothelin-1 participates in sodium and water handling, and its urinary excretion is increased in sodium-retentive states. We compared the cortical and medullary renal expression of prepro-endothelin-1, endothelin-converting enzyme-1, and endothelin type A and type B receptors in patients who underwent nephrectomy after normal (108 mmol/d NaCl; n=6) or low (20 mmol/d NaCl; n=6) sodium diet and investigated whether sodium exerts a direct role on endothelin receptor binding in vitro. With normal sodium diet prepro-endothelin-1 mRNA was 3-fold higher in renal medulla than in cortex (P<0.01), whereas endothelin-converting enzyme-1 mRNA was equally distributed. Endothelin-1 receptor density was 2-fold higher in renal medulla than in cortex (P<0.05). Type B was the main receptor subtype in both regions. In the renal cortex, low sodium diet caused a 194% increase in prepro-endothelin-1 mRNA (P<0.05), whereas endothelin-converting enzyme-1 type B and type A receptors remained unchanged. In contrast, in the renal medulla the increase in prepro-endothelin-1 mRNA (+30%, P<0.05) was associated with a selective increase in type B receptor for both mRNA expression (+37%, P<0.05) and binding density (+55%, P<0.05). Increasing in vitro sodium concentrations between 154 and 308 mmol/L significantly enhanced type B receptor density (P<0.05) and affinity (P<0.05). In conclusion, during low sodium diet, renal prepro-endothelin-1 synthesis increases mainly in the renal cortex (where no changes in receptors occur), whereas type B receptor is selectively enhanced in the renal medulla. The range of sodium concentrations that are physiologically present in vivo in the renal medulla selectively modulate type B receptor density and affinity.
Abstract: The role of angiotensin II in pressure overload is still debated because notwithstanding its effects on myocyte contractility angiotensin II is not an obligatory factor for the development of hypertrophy. To define the role of angiotensin II in acute pressure overload we studied the effects of AT1 blockade (valsartan 80mg per day) on myocardial contractility, cardiac growth factor gene expression, and myocardial hypertrophy in aortic banded (60mmHg) pigs. Acute pressure overload caused an abrupt reduction of myocardial contractility, measured by the end-systolic stiffness constant, and a sharp increase in end-systolic stress which rapidly normalized (within 12h) in the placebo group. In AT1-blocked animals end-systolic stiffness constant remained significantly depressed up to 24h and end-systolic stress was still elevated up to 48h (both P<0.05 vs placebo). In both groups confocal microscopy revealed that granular staining of angiotensin II in cardiomyocyte cytoplasm disappeared after 30min of pressure overload. AT1 blockade abolished following cardiac overexpression of angiotensinogen and endothelin-1 genes as shown in RT-PCR studies and the consequent angiotensin II and endothelin-1 release in the coronary circulation. Conversely, insulin-like growth factor-I and ACE mRNA overexpression, as well as the onset of left ventricular mass increase, were not significantly affected by AT1 blockade. In conclusion: (1) mechanical stress releases preformed angiotensin II from myocyte in vivo; (2) the AT1 blockade abolishes cardiac angiotensin II and endothelin-1 production with delayed recovery of myocardial contractility; whereas (3) the overexpression of insulin-like growth factor-I gene and the development of myocardial hypertrophy are not angiotensin II-mediated effects.
Abstract: We evaluated the changes in sarcoplasmic reticulum (SR) function and the parallel hemodynamic and morphological modifications in a heart subjected to volume overload. We also determined the levels of acylphosphatase, a cytosolic enzyme, that could play a regulatory effect on SR Ca(2+) pump by hydrolyzing the phosphorylated intermediate of this transport system. For this, swine hearts were subjected to volume overload by aorta-cava shunt for 1, 2, or 3 months. Changes in heart contractility reflected modifications of SR function, whose reduction after 1 month of overload was followed by a gradual recovery. A decrease in SERCA2a protein and mRNA content was shown from 1 month and remained for the following 2 months. Phospholamban content and its phosphorylation status were not modified. Acylphosphatase was unchanged at 1 month, but at 2 months this enzyme exhibited an increased activity, protein and mRNA expression. Morphological alterations consisting of the cytoskeletal architectures, intermyofibrillar oedema, swollen mitochondria and abnormality of the membrane system (T-tubule and SR cisternae) were particularly evident after 1 month but almost disappeared after 3 months. These results suggest that our overloaded hearts underwent a substantial recovery of their structural and biochemical properties at 3 months after surgery. A possible involvement of acylphosphatase in the modification of SR function is discussed.
Abstract: In 76 patients with heart failure (HF) (New York Heart Association [NYHA] classes I through IV) and in 15 control subjects, cardiac angiotensin II (Ang II) generation and its relationship with left ventricular function were investigated by measuring aorta-coronary sinus concentration gradients of endogenous angiotensins and in a part of patients by studying (125)I-labeled Ang I kinetics. Gene expression and cellular localization of the cardiac renin-angiotensin system components, the density of AT(1) and AT(2) on membranes and isolated myocytes, and the capacity of isolated myocytes for synthesizing the hypertrophying growth factors insulin-like growth factor-I (IGF-I) and endothelin (ET)-1 were also investigated on 22 HF explanted hearts (NYHA classes III and IV) and 7 nonfailing (NF) donor hearts. Ang II generation increased with progression of HF, and end-systolic wall stress was the only independent predictor of Ang II formation. Angiotensinogen and angiotensin-converting enzyme mRNA levels were elevated in HF hearts, whereas chymase levels were not, and mRNAs were almost exclusively expressed on nonmyocyte cells. Ang II was immunohistochemically detectable both on myocytes and interstitial cells. Binding studies showed that AT(1) density on failing myocytes did not differ from that of NF myocytes, with preserved AT(1)/AT(2) ratio. Conversely, AT(1) density was lower in failing membranes than in NF ones. Ang II induced IGF-I and ET-1 synthesis by isolated NF myocytes, whereas failing myocytes were unable to respond to Ang II stimulation. This study demonstrates that (1) the clinical course of HF is associated with progressive increase in cardiac Ang II formation, (2) AT(1) density does not change on failing myocytes, and (3) failing myocytes are unable to synthesize IGF-I and ET-1 in response to Ang II stimulation.
Abstract: Only scarce information is available on the activity and modifications of the cardiac endothelin (ET)-1 system in heart failure due to ischemic (ICM) or idiopathic dilated (DCM) cardiomyopathy. The activity of the ET-1 system was investigated by measuring cardiac ET-1 and big ET-1 formation and quantifying cardiac mRNA for prepro-ET-1 (ppET-1), ET-converting enzyme-1, and ET(A) and ET(B) receptors both in myocardium and in isolated myocytes using Northern blot, reverse transcription-polymerase chain reaction, and in situ hybridization in 22 patients with DCM and 20 with ICM who underwent cardiac transplantation and in 7 potential heart transplant donors (nonfailing hearts). Notwithstanding a similar increase of plasma ET-1 in the 2 groups, cardiac ET formation, mRNA levels for ppET-1, and ET(A) and ET(B) receptors were higher on both the myocardium and isolated myocytes from ICM than on those from DCM hearts (P<0.001 for all). ppET-1 and ET-converting enzyme-1 mRNAs were expressed on myocytes and endothelial and interstitial cells in ICM, whereas in DCM and nonfailing hearts they were mainly expressed on nonmyocyte cells. In both ICM and DCM, the ET(A) mRNA signal was expressed on both myocytes and nonmyocyte cells, whereas ET(B) mRNA was almost exclusively localized on nonmyocyte cells. ET(A)- and ET(B)-specific receptor binding was increased on both myocytes and cardiac membranes, showing a positive correlation with left ventricular ejection fraction in ICM (r=0.78 and 0.70) but not in DCM patients. The present results show that human ventricular myocytes express all of the components of the ET-1 system, which is selectively upregulated in ICM patients and appears to be functionally important in the maintenance of cardiac function.
Abstract: To investigate the time sequence of cardiac growth factor formation, echocardiographic and hemodynamic measurements were performed at scheduled times, and mRNAs for angiotensinogen, prepro-endothelin-1 (ppET-1), and insulin-like growth factor I (IGF-I) were quantified with RT-PCR and localized with in situ hybridization in pigs (fluothane anesthesia) by use of pressure or volume overload (aortic banding and aorta-cava fistula, respectively). Relative peptide formation was also measured by radioimmunoassay. In pressure overload, angiotensinogen and ppET-1 mRNA overexpression on myocytes (13 times vs. sham at 3 h and 112 times at 6 h, respectively) was followed by recovery (12 h) of initially decreased (0.5-6 h) myocardial contractility. In volume overload, contractility was not decreased, the angiotensinogen gene was slightly upregulated at 6 h (6.7 times), and ppET-1 was not overexpressed. IGF-I mRNA was overexpressed on myocytes (at 24 h) in both volume and pressure overload (14 times and 37 times, respectively). In the latter setting, a second ppET-1 overexpression was detectable on myocytes at 7 days. In conclusion, acute cardiac adaptation responses involve different growth factor activation over time in pressure versus volume overload; growth factors initially support myocardial contractility and thereafter induce myocardial hypertrophy.
Abstract: A blood pressure increase was reported in black immigrants from Africa to Western countries. The present study was undertaken to evaluate whether an impairment of the cardiopulmonary reflex might make blacks unable to adapt peripheral vascular resistance to increased sodium intake. Ten normotensive clinically healthy blacks (aged 38+/-6 years) who had recently migrated from Mogadishu, Somalia to Florence and 10 age- and gender-matched healthy white subjects were investigated. Cardiopulmonary baroreceptor reflex was studied after 7 days of normal (108 mEq) and low (30 mEq) sodium intake by assessing forearm vascular resistance (FVR) and central venous pressure (CVP) during the application of lower body negative pressure (LBNP) at -10 and -20 mm Hg. With a normal sodium diet the gain in cardiopulmonary baroreceptor reflex, expressed as the FVR increase per mm Hg of CVP reduction, was significantly lower in blacks than in white subjects (2.6+/-1.1 v 5.1+/-1.1 U per mm Hg of CVP, P < .001). Differences between the groups disappeared with a low-sodium diet because the reduction of the efficiency of the cardiopulmonary baroreceptor reflex was lower in blacks than in whites (2.4+/-0.7 v 3.3+/-0.7 U per mm Hg of CVP, P = .09). In conclusion, the efficiency of the cardiopulmonary reflex is lower in normotensive black immigrants than in whites. The lower adaptation of the cardiovascular system to the Western sodium diet could contribute to reported long-term blood pressure increase.
Abstract: The aim of the present study was to investigate whether and which cardiac growth factors are involved in human hypertrophy, whether growth factor synthesis is influenced by overload type and/or by the adequacy of the hypertrophy, and the relationships between cardiac growth factor formation and ventricular function. Cardiac growth factor formation was assessed by measuring aorta-coronary sinus concentration gradient in patients with isolated aortic stenosis (n=26) or regurgitation (n=15) and controls (n=12). Gene expression and cellular localization was investigated in ventricular biopsies using reverse transcriptase-polymerase chain reaction and in situ hybridization. Cardiac hypertrophy with end-systolic wall stress <90 kdyne/cm2 was associated with a selective increased formation of insulin-like growth factor (IGF)-I in aortic regurgitation and of IGF-I and endothelin (ET)-1 in aortic stenosis. mRNA levels for IGF-I and preproET-1 were elevated and mainly expressed in cardiomyocytes. At stepwise analysis, IGF-I formation was correlated to the mean velocity of circumferential fiber shortening (r=0.86, P<0.001) and ET-1 formation to relative wall thickness (r=0.82, P<0. 001). When end-systolic wall stress was >90 kdyne/cm2, IGF-I and ET-1 synthesis by cardiomyocytes was no longer detectable, and only angiotensin (Ang) II was generated, regardless of the type of overload. The mRNA level for angiotensinogen was high, and the mRNA was exclusively expressed in the interstitial cells. Ang II formation was positively correlated to end-systolic stress (r=0.89, P<0.001) and end-diastolic stress (r=0.84, P<0.001). Multivariate stepwise analysis selected end-systolic stress as the most predictive variable and left ventricular end-diastolic pressure as the independent variable for Ang II formation (r=0.93, P<0.001). In conclusion, the present results indicate that the course of human left ventricular hypertrophy is characterized by the participation of different cardiac growth factors that are selectively related both to the type of hemodynamic overload and to ventricular function.
Abstract: To evaluate the physiological basis for suboptimal peak exercise oxygen consumption (VO2p) observed in the early stage of hypertension, 25 WHO Stage I hypertensive men with normal left ventricular mass and 10 healthy control subjects of equivalent age underwent the maximal cardiopulmonary exercise test with contemporary measurement of cardiac output with Tc99m angiocardiography. At peak exercise hypertensive patients had lower VO2p (p < 0.045) and cardiac output (p < 0.014) and higher vascular resistance (p < 0.010) than controls. At multiple regression analysis VO2 was positively related to cardiac output in controls (r = 0.80, p < 0.02), whereas in hypertensives the best (negative) correlation was observed with peripheral vascular resistance (r = -0.72, p < 0.04). Thus reduced cardiopulmonary function during physical exercise in hypertensives seems to be mainly related to impaired peripheral vascular autoregulation.
Abstract: On cardiac membranes and isolated cardiomyocytes from the human heart, cell-type distribution and functional activities of endothelin-1 (ET-1) receptor subtypes were investigated by using binding methods and messenger RNA (mRNA) in situ hybridization. The ET-receptor antagonist BMS-182874 selectively and competitively inhibits ET(A) receptors both on isolated myocytes and ventricular membranes with approximately 1,300 times greater affinity for ET(A) than ET(B) subtypes. The [125I]-ET-1 specific binding revealed 42.851+/-2,546 receptors/myocyte with a prevalent proportion of ET(A)-receptor subtypes on both myocytes (84+/-2%) and ventricular membranes (66+/-3%). In situ hybridization studies revealed that mRNA for ET(A) receptors was expressed on both myocytes and nonmyocyte cells, whereas mRNA for ET(B) receptors was almost exclusively expressed on fibroblasts and endothelial cells. Specific binding of [125I]-ET-1 to both myocytes and ventricular membranes in the presence of specific ET(A) (BMS-182874) and ET(B) (BQ-788)-receptor antagonists showed a displacement of [125I]-ET-1 by unlabeled ET-1, which were significantly faster from ET(B) than from ET(A). This suggests a clearance function of ventricular ET(B) receptors.
Abstract: The present study aimed to investigate endothelin-1 (ET-1) receptors in human and swine cardiomyocytes with binding studies using ET(A) and ET(B) selective receptor antagonists (BMS-182874 and BQ-788, respectively). Cell distribution of mRNA expression for ET(A) and ET(B) subtypes was investigated by in situ hybridization using specific cDNA probes. The 1251-ET-1 binding, which reached equilibrium in about 120 min (Kobs = 0.051+/-0.003 min(-1)), was only partially displaceable by the addition of a large excess of ET-1 (about 15% with a half-life of 20 min). In equilibrium binding studies, 125I-ET-1 had a Kd of 0.43+/-0.08 nM and a maximum binding (Bmax) of 42.8+/-6.6 fmol/mg protein. ET(A) and ET(B) receptors are represented in human and swine cardiomyocytes with an 85:15 ratio as indicated by the biphasic pattern of competition of both BMS-182874 and BQ-788. In situ hybridization studies confirmed that myocytes mainly expressed mRNA for ET(A), whereas expression of mRNA for the ET(B) subtype was documented in non-myocyte cells. These results showed that ET-1 binds with high affinity and poor reversibility to specific receptors, in both human and swine isolated ventricular cardiomyocytes, without significant species differences.
Abstract: To investigate whether renal endothelin (ET)-1 participates in water and sodium handling, we investigated the influence of different sodium intakes on renal production of ET-1 in eight healthy subjects. The functional relationship with the renin-angiotensin system was also studied. Renal ET-1 formation is affected by sodium intake, because 1 wk of high sodium decreased urinary ET-1 excretion (-34%, P < 0.05), whereas a low-sodium diet increased ET-1 excretion (66%, P < 0.05) and mRNA expression for preproendothelin-1 in epithelial cells of medullary collecting ducts and endothelial cells of the peritubular capillary network. Increased ET-1 renal synthesis was associated with sodium retention and increased free water clearance. Urinary ET-1 excretion changes from normal to low-sodium diet were negatively related to contemporary changes in sodium excretion (r = 0.97, P < 0.05) and were positively correlated with free water clearance (r = 0.97, P < 0.05). These correlations were maintained during angiotensin-converting enzyme inhibition, which only partially reduced ET-1 renal excretion. These results indicate that renal ET-1 production is indeed modulated by varying sodium intakes and may exert a role in sodium and water handling.
Abstract: Plasma endothelin (ET-1) and renal endothelin are two distinct functional systems involved in maintaining blood volume. To investigate whether plasma and renal ET-1 participate in the cardiovascular response to exercise-induced hypovolaemia, we studied changes in plasma and urinary ET-1 in healthy non-professional athletes after 2 h of jogging performed both without and with drinking isotonic fluids. After the run, which caused a 13% plasma volume (PV) reduction, plasma and renal ET-1 (+117% and +118%) increased significantly (all P < 0.01). Fluid loss restitution during the run significantly attenuated either the PV contraction (-1.2%) and plasma and renal ET-1 increase (+2 and +3%). At multiple regression analysis changes in AVP plasma concentration, and not in PRA or PV per se, were significantly related to ET-1 changes both in plasma and urine. The present findings indicate that both plasma and renal ET-1 participate in the cardiovascular response to hypovolaemia induced by long-lasting, dynamic exercise.
Abstract: We measured the level of second messengers, the activity of carbohydrate metabolism enzymes, and the resistance to ionizing radiations in normal 32D hematopoietic cells, in v-erbB transformants and in spontaneous transformants. v-erbB and spontaneous transformants were resistant to radiations as compared with their normal counterpart. The second messenger diacylglycerol was elevated in radioresistant clones. Only v-erbB transformants showed increase of the activities of enolase and glucose-6-phosphate dehydrogenase. v-erbB-transformed NIH/3T3 cells, selected as control, showed identical correlation between radioresistance, increase of diacylglycerol, and of enolase and glucose-6-phosphate dehydrogenase activity. These results indicate that increase of diacylglycerol is correlated with resistance to the killing effect of ionizing radiations and could be proposed as a marker of radioresponse.
