endothelin-1 and omapatrilat

Initial pharmacologic therapy for hypertension is low-dose thiazide diuretics, beta-blockers, and ACE inhibitors. Increasing data have confirmed that ACE inhibitors have specific benefit in patients with diabetes, atherosclerosis, left ventricular dysfunction, and renal insufficiency. CCBs are alternative agents for ISH in the elderly and appear to decrease stroke with perhaps less protection against progression of renal insufficiency and proteinuria, CAD mortality and new onset heart failure versus other initial agents, especially ACE inhibitors. ARBs are well tolerated and effective blood pressure lowering agents but have not been confirmed as effective as ACE inhibitors for reducing renal progression, clinical events, or mortality from heart failure. Effective pharmacologic antihypertensive therapy may avoid disabling and undetected cerebrovascular disease, cognitive dysfunction, and disturbing symptoms of elevated blood pressure. Vasopeptidase inhibitor, such as omapatrilat, and endothelin-1 antagonist, such as bosentan, may become future agents approved for the reduction of morbidity and mortality with hypertension. The ALLHAT trial continues to examine the potential benefits and harms of amlodipine versus chlorthalidone and lisinopril in a diverse high-risk population. Based on ALLHAT data, however, doxazosin is no longer an acceptable initial pharmacological agent. Intensive pharmacologic treatment with blood pressure lowering to less than 130/85 mm Hg is recommended with diabetes, renal insufficiency, and heart failure with additional goal of less than 125/75 mm Hg with renal failure and proteinuria greater than 1 g/24 h, based on multiple outcome studies.

Topics: Adrenergic beta-Antagonists; Aged; Aged, 80 and over; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Arteriosclerosis; Bosentan; Bradykinin; Calcium Channel Blockers; Diabetes Complications; Diuretics; Drug Therapy, Combination; Endothelin-1; Female; Heart Failure; Humans; Hypertension; Male; Middle Aged; Patient Compliance; Pyridines; Quality of Life; Renal Insufficiency; Renin-Angiotensin System; Risk Factors; Sulfonamides; Systole; Thiazepines; Treatment Outcome

Angiotensin-converting enzyme (ACE) inhibitors exert their effects by modulating the neurohumoral milieu. Vasopeptidase inhibitors (VPI) are ACE and neutral endopeptidase inhibitors and may increase natriuretic peptides, bradykinin, and perhaps endothelin-1 in patients with congestive heart failure. Patients (n = 107) with ischemic or dilated cardiomyopathy, New York Heart Association functional class II to III, with left ventricular ejection fraction <40%, and on ACE inhibitor therapy were randomized to either the VPI omapatrilat 40 mg/day or the ACE inhibitor lisinopril 20 mg/day. Trough levels of neurohormones (24 hours after dosing) were assessed at baseline, and at 12 and 24 weeks of follow-up. C-terminal atrial natriuretic peptide (C-ANP) levels decreased with lisinopril (p = 0.035), but not with omapatrilat. In contrast, N-terminal ANP levels did not change, and brain natriuretic peptide (BNP) levels tended to decrease similarly in both groups. Endothelin-1 levels increased in both groups, the increase reaching statistical significance with omapatrilat (p = 0.008). Levels of the proinflammatory cytokine interleukin-6 tended to decrease, and the anti-inflammatory cytokine interleukin-10 increased in both groups, with statistical significance only for interleukin-10 with omapatrilat therapy. Neither agent changed catecholamines or angiotensin II. Thus, even at trough levels, omapatrilat potentiates C-ANP more than lisinopril. Potentially important effects of omapatrilat on endothelin-1 and anti-inflammatory cytokines were identified, providing potential explanations for differences in clinical outcome.

Topics: Aged; Angiotensin-Converting Enzyme Inhibitors; Atrial Natriuretic Factor; Biomarkers; Chronic Disease; Cytokines; Double-Blind Method; Endothelin-1; Female; Follow-Up Studies; Heart Failure; Humans; Lisinopril; Male; Middle Aged; Natriuretic Peptide, Brain; Neurotransmitter Agents; Predictive Value of Tests; Prospective Studies; Pyridines; Stroke Volume; Thiazepines; Treatment Outcome

The in vivo inhibition of angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP) were monitored simultaneously by sequentially measuring the urinary excretion of N-Acetyl-Ser-Asp-Lys-Pro and of the atrial natriuretic factor to compare the magnitude and the duration of action of a vasopeptidase inhibitor, omapatrilat, and an ACE inhibitor, fosinopril. Single oral doses of 40 or 80 mg of omapatrilat or 20 mg of fosinopril were administered to 24 normotensive, sodium-depleted or -replete volunteers in a placebo-controlled crossover study. ACE inhibition persisted longer after treatment with omapatrilat than with fosinopril, and there was no major difference between the effects of 40 and 80 mg of omapatrilat. The duration of NEP inhibition by omapatrilat was shorter than that of ACE inhibition. Although omapatrilat effectively inhibited NEP, it had a mild and transient natriuretic effect and did not increase natriuresis more than fosinopril. Omapatrilat induced a decrease in BP and an increase in plasma renin more rapidly and more effectively than fosinopril. The BP and renin effects of omapatrilat persisted despite high sodium intake, which neutralized the effects of fosinopril. The simultaneous inhibition of ACE and NEP may be more effective in reducing BP than the inhibition of ACE alone and less dependent on sodium balance.

Topics: Adult; Angiotensin-Converting Enzyme Inhibitors; Atrial Natriuretic Factor; Blood Pressure; Cross-Over Studies; Double-Blind Method; Endothelin-1; Endothelins; Fosinopril; Humans; Male; Neprilysin; Oligopeptides; Peptidyl-Dipeptidase A; Protease Inhibitors; Protein Precursors; Pyridines; Renin; Sodium, Dietary; Thiazepines; Time Factors

We aimed to assess in patients with congestive heart failure whether dual inhibition of neutral endopeptidase and angiotensin-converting enzyme (ACE) with the vasopeptidase inhibitor omapatrilat is better than ACE inhibition alone with lisinopril on functional capacity and clinical outcome.. We did a prospective, randomised, double-blind, parallel trial of 573 patients with New York Heart Association (NYHA) class II-IV congestive heart failure, left-ventricular ejection fraction of 40% or less, and receiving an ACE inhibitor. Patients were randomly assigned omapatrilat at a daily target dose of 40 mg (n=289) or lisinopril at a daily target dose of 20 mg (n=284) for 24 weeks. The primary endpoint was improvement in maximum exercise treadmill test (ETT) at week 12. Secondary endpoints included death and comorbid events indicative of worsening heart failure.. Week 12 ETT increased similarly in the omapatrilat and lisinopril groups (24 vs 31 s, p=0.45). The two drugs were fairly well tolerated, but there were fewer cardiovascular-system serious adverse events in the omapatrilat group than in the lisinopril group (20 [7%] vs 34 [12%], p=0.04). There was a suggestive trend in favour of omapatrilat on the combined endpoint of death or admission for worsening heart failure (p=0.052; hazard ratio 0.53 [95% CI 0.27-1.02]) and a significant benefit of omapatrilat in the composite of death, admission, or discontinuation of study treatment for worsening heart failure (p=0.035; 0.52 [0.28-0.96]). Omapatrilat improved NYHA class more than lisinopril in patients who had NYHA class III and IV (p=0.035), but not if patients with NYHA class II were included.. Our findings suggest that omapatrilat could have some advantages over lisinopril in the treatment of patients with congestive heart failure. Thus use of vasopeptidase inhibitors could constitute a potentially important treatment for further improving the prognosis and well being of patients with this disorder.

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Atrial Natriuretic Factor; Double-Blind Method; Endothelin-1; Exercise Tolerance; Female; Heart Failure; Humans; Lisinopril; Male; Middle Aged; Neprilysin; Norepinephrine; Prospective Studies; Pyridines; Radionuclide Ventriculography; Severity of Illness Index; Survival Rate; Thiazepines; Treatment Outcome

To investigate the effects of omapatrilat (OMA) on endothelin-1-induced proliferation of cardiac fibroblasts (CFs).. Isolated and cultured CFs from neonatal Sprague-Dawley rats (SD) were randomly divided into 7 groups: (1) Control, (2) ET-1, (3) OMA, (4) ET-1 + OMA 10(-9) mol/L, (5) ET-1 + OMA 10(-8) mol/L, (6) ET-1 + OMA 10(-7) mol/L and (7) ET-1 + OMA 10(-6) mol/L. CFs were counted by MTT assay. Cell cycle distribution was determined with a flow cytometer (FCM). [3H]-Proline incorporation was evaluated by scintillation counting. Nitric oxide (NO) was measured by colorimetry.. 10(-7) mol/L ET-1 significantly increased A490 value and [3H]-Pro incorporation and decreased NO secretion compared with the control group (P < 0.01). 10(-9)-10(-6) mol/L OMA inhibited the effects of ET-1 on CFs in a concentration-dependent manner (P < 0.01 vs. ET-1). In the ET-1 group, the percentage of cells in the S phase was higher than control, which was inhibited by l0(-6) mol/L OMA (P < 0.01 vs. ET-1 and control).. OMA can restrain the proliferation and collagen synthesis of cardiac fibroblasts induced by endothelin-1, and this effect may be partially mediated by NO.

Topics: Animals; Cell Proliferation; Cells, Cultured; Collagen; Endothelin-1; Fibroblasts; Myocytes, Cardiac; Nitric Oxide; Pyridines; Rats; Rats, Sprague-Dawley; Thiazepines

Inhibition of nitric oxide synthases causes systemic hypertension and renal injury in rats. Our objective was to examine whether omapatrilat, a vasopeptidase inhibitor that inhibits both angiotensin-converting enzyme (ACE) and neutral endopeptidase, could induce better regression of renal injury than ACE inhibitor alone. Ten groups of rats were studied. They were fed either a normal (0.8% NaCl) or a high (4% NaCl) sodium diet. Eight of these groups received NG-nitro-L-arginine methyl ester (L-NAME, 20 mg x kg(-1) x d(-1)) in their drinking water. After 4 weeks, 1 group on each diet was killed and considered the L-NAME group, whereas the others received L-NAME alone, captopril (200 mg x kg(-1) x d(-1)) plus L-NAME, or omapatrilat (80 mg x kg(-1) x d(-1)) plus L-NAME for 4 additional weeks. In rats receiving L-NAME alone for 8 weeks, the mortality rate was approximately 90%, irrespective of the diet. In contrast, all rats survived in the captopril and the omapatrilat groups. In rats fed a normal-sodium diet, captopril and omapatrilat normalized systolic blood pressure and induced a complete regression of renal injury. Creatinine clearance and proteinuria were also normalized. In the high-sodium-diet groups, both treatments were less efficient: blood pressure remained elevated, and the regression of renal fibrosis was only partial. Although proteinuria decreased significantly with captopril or omapatrilat, creatinine clearance remained lower than in the controls. These results demonstrate that, in nitric oxide-deficient rats fed a normal-sodium diet, ACE and vasopeptidase inhibitors exhibit a marked renoprotective effect, whereas these treatments are less efficient in rats fed a high-sodium diet.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Blood Vessels; Captopril; Cyclic GMP; Endothelin-1; Enzyme Inhibitors; Fibrosis; Hypertension, Renal; Kidney; Male; Neprilysin; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Protease Inhibitors; Pyridines; Rats; Rats, Sprague-Dawley; Sodium Chloride; Survival Rate; Thiazepines

Omapatrilat represents a new class of drugs capable of inhibiting both ACE and neutral endopeptidase 24.11, the so-called vasopeptidase inhibitors. It therefore contributes to neurohumoral modulation, which might improve endothelial function in cardiovascular diseases. This study investigated the effect of omapatrilat in comparison to the ACE inhibitor captopril on systolic blood pressure and endothelial function in salt-induced hypertension. Dahl salt-sensitive rats (n=6/group) on standard or salt-enriched (4% NaCl) chow were treated for 8 weeks with either omapatrilat (36+/-4 mg/kg per day), captopril (94+/-2 mg/kg per day), or placebo. Aortic rings were then isolated and suspended in organ chambers for isometric tension recording. Systolic blood pressure of salt-fed, placebo-treated animals increased to 196+/-6 mm Hg, which was prevented by omapatrilat (162+/-5 mm Hg, P<0.05) and captopril (164+/-7 mm Hg, P<0.05) to a comparable degree. In control rats, acetylcholine (10(-10) to 10(-5) mol/L) induced endothelium-dependent relaxation (97+/-4%), which was reduced by high-salt diet to 30+/-5% (P<0.005; n=6). Omapatrilat improved relaxation to a greater extent (86+/-5%) than did captopril (57+/-6%; P<0.05). eNOS protein expression and aortic nitrite/nitrate content were reduced in hypertensive rats and improved by both omapatrilat and captopril. Aortic endothelin-1 levels were increased in salt-fed animals and unaffected by omapatrilat or captopril. These data suggest that despite comparable blood pressure, omapatrilat is superior to captopril in improving endothelium-dependent relaxation in salt-sensitive hypertension.

Topics: Analysis of Variance; Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta; Blood Pressure; Captopril; Endothelin-1; Endothelium, Vascular; Enzyme Inhibitors; Hypertension; Male; Neprilysin; Nitrates; Nitric Oxide Synthase; Nitrites; Pyridines; Regression Analysis; Renal Artery; Sodium, Dietary; Statistics, Nonparametric; Thiazepines; Vasoconstriction; Vasodilation

Vasopeptidase inhibition (VPI) represents a new therapeutic principle including both inhibition of angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP). The present study investigated the effect of the vasopeptidase inhibitor omapatrilat on endothelin-1 (ET-1)-mediated vascular function in salt-induced hypertension.. Dahl salt-sensitive rats (n=6/group) on standard or salt-enriched (4% NaCl) chow were treated for 8 weeks with either omapatrilat (36+/-4 mg/kg/day), captopril (94+/-2 mg/kg/day) or placebo. Aortic and renal artery segments were isolated and suspended in organ chambers for isometric tension recording. Functional endothelin-converting enzyme (ECE) activity was assessed in native segments and after preincubation with omapatrilat. Furthermore, vascular ECE protein levels as well as plasma and tissue ET-1 levels were determined.. The increase in systolic blood pressure of salt-fed rats was prevented by omapatrilat and captopril to a comparable degree. In salt-induced hypertension, functional ECE activity (calculated as the ratio of the contraction to big ET-1 divided by the contraction to ET-1) in renal arteries (0.46+/-0.05) and in aorta (0.68+/-0.05) was reduced as compared with control animals (0.9+/-0.05 and 0.99+/-0.04, respectively; P<0.05). While omapatrilat in vitro blunted the response to big endothelin-1 (big ET-1) and diminished ECE activity further (P<0.01 vs native segments), chronic treatment with omapatrilat in vivo restored contractions to ET-1 (120+/-6%) and big ET-1 (98+/-9%) in renal arteries, and therefore normalized renovascular ECE activity. In addition, omapatrilat normalized plasma ET-1 concentrations (12.9+/-1.2 vs 16.6+/-1.4 pg/ml on high salt diet; P<0.05) and renovascular ECE protein levels.. In salt-induced hypertension, vasopeptidase inhibition restores alterations in the endothelin system, such as renovascular ECE activity and responsiveness to ET-1 and big ET-1 with chronic but not acute in vitro application. Thus, the beneficial effects of vasopeptidase inhibition may reflect a resetting of cardiovascular control systems and therefore may be particularly suited to treat hypertension and heart failure.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta; Captopril; Endothelin-1; Endothelins; Enzyme Inhibitors; Hypertension; Male; Metalloendopeptidases; Neprilysin; Protein Precursors; Pyridines; Rats; Rats, Inbred Dahl; Renal Artery; Sodium, Dietary; Thiazepines