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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypertension and hypercholesterolemia predispose to atherosclerosis. Ramipril, known to lower blood pressure, was used to study the effect of converting-enzyme inhibition on impairment of endothelium-derived relaxation and changes in basal cGMP content in rabbits fed an atherogenic diet (0.25% cholesterol). The generation of cGMP in the presence of bradykinin and ramiprilat was studied in vitro in aortic segments from normal untreated rabbits as well as in bovine endothelial cells. The ability to relax in response to acetylcholine was almost abolished in aortic segments from the vehicle-treated rabbits fed the atherogenic diet for 4 months. The basal cGMP content was substantially reduced. Aortic segments from rabbits concomitantly treated with ramipril (0.3 and 3.0 mg/kg/day) for 3 months showed well-preserved relaxation and matching basal cGMP content compared to normal controls. The relaxation was not significantly greater in aortic segments from ramipril-treated rabbits fed the standard diet, but the cGMP content was more than doubled. In vitro studies in aortic segments and in endothelial cells showed that both the ramiprilat and bradykinin concentrations dependently stimulated cGMP formation, which serves as a biochemical marker of nitric oxide or EDRF release. Thus, the observed endothelial protection against hypercholesterolemia by ramipril may be the result of continuously increased cGMP formation due to preserved EDRF release. This is presumably produced by enhanced bradykinin activity through inhibition of degradation by converting-enzyme inhibition with ramipril.
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PMID:Preservation of endothelial function by ramipril in rabbits on a long-term atherogenic diet. 172 17

From pharmacologic investigations and clinical studies it is known that angiotensin-converting enzyme (ACE) inhibitors exhibit additional local actions, which are not related to hemodynamic changes and which cannot be explained simply by interference with the renin-angiotensin system with subsequent inhibition of angiotensin II formation. Because ACE is identical to kininase II, which inactivates the nonapeptide bradykinin (BK), potentiation of BK might be responsible for these additional effects of ACE inhibitors. To prove the specificity of BK-mediated effects by ACE inhibition, we used the specific B2 kinin receptor antagonist HOE 140 in different models: endothelial cell cultures; atherosclerosis in high-cholesterol-fed rabbits; neointima formation with smooth cell proliferation and migration after endothelial denudation in rats; myocardial ischemia in rats, rabbits, and dogs; and left ventricular hypertrophy in rats. The beneficial effects of ramipril or BK given in non-blood pressure-lowering doses in these models were abolished by HOE 140 (icatibant). Ramipril exerts cardioprotective effects in different experimental models. The formation of the endothelial autacoids nitric oxide and prostacyclin, enhanced when BK degradation is inhibited by ACE inhibition, may contribute to the observed beneficial effects.
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PMID:Contribution of bradykinin to the cardiovascular effects of ramipril. 751 34

We report the effects of isradipine and ramipril on regression of diet-induced atherosclerosis in rabbits. Regression of diet-induced atherosclerosis was not significantly affected by ramipril, but isradipine significantly retarded regression. Thirty rabbits in three groups were fed a 0.3% cholesterol diet for 4 weeks. After this induction period, group IIr received the 0.3% cholesterol diet, group IIIr received the 0.3% cholesterol diet with isradipine (0.33 mg/kg/day), and group IVr received the 0.3% cholesterol diet with ramipril (0.33 mg/kg/day) for 12 more weeks. The rabbits then received a standard diet and remained on their respective drug regimen for 12 more weeks. Group Ir (10 rabbits) received a standard diet for 28 weeks. Acetylcholine (ACh)-induced maximal endothelium-dependent relaxations (EDR) of aortic rings were significantly less in group IIr (22.8 +/- 3.2%) than in group Ir (66.4 +/- 4.0%; p < 0.05). Ramipril and isradipine did not improve EDR as compared with group IIr. Regression of atherosclerosis was accompanied by an improved endothelium-dependent releasing factor (EDRF) release from the endothelium, but ramipril and isradipine did not promote this process. In addition, regression was associated with increasing sensitivity of vascular smooth muscle to EDRF that was significantly retarded by isradipine but not ramipril. Basal cyclic GMP levels were significantly reduced in aortic rings from group IIr as compared with group Ir. Ramipril, but not isradipine, restored basal cyclic GMP levels to control values. Both isradipine and ramipril protect against endothelial degeneration in hypercholesterolemic rabbits. However, isradipine but not ramipril inhibits regression of diet-induced atherosclerosis in rabbits.
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PMID:Comparison of the antiatherogenic effects of isradipine and ramipril in cholesterol-fed rabbits: II. Effect on regression of atherosclerosis and restoration of endothelial function. 751 86

Atherosclerotic cardiovascular disease remains a major cause of mortality and morbidity in most developed countries. Experimental and clinical evidence suggests that angiotensin-converting enzyme inhibitors and vitamin E therapy may retard the atherosclerotic process; however, definitive proof in humans is lacking. The Study to Evaluate Carotid Ultrasound Changes in Patients Treated with Ramipril and Vitamin E (SECURE) is designed to assess the effects of ramipril--an angiotensin-converting enzyme inhibitor, at 2 doses: 2.5 mg daily (which has little effect on lowering blood pressure) and 10 mg daily--and the antioxidant vitamin E, 400 IU daily, on atherosclerosis progression in 732 patients using a factorial 3 x 2 study design. High-risk patients with a documented history of significant cardiovascular disease or with diabetes and additional risk factors were enrolled and will be followed for 4 years. The extent and progression of atherosclerosis are assessed noninvasively by B-mode carotid ultrasonography. The SECURE trial is a substudy of the larger Heart Outcomes Prevention Evaluation (HOPE) study of 9,541 high-risk patients evaluating the effects of ramipril and vitamin E on major cardiovascular events (cardiovascular death, myocardial infarction, and stroke). The 2 studies are complementary. Whereas HOPE is expected to provide information on major clinical outcomes, SECURE will shed light on the mechanisms by which these effects may be mediated.
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PMID:Study design and baseline characteristics of the study to evaluate carotid ultrasound changes in patients treated with ramipril and vitamin E: SECURE. 888 65

We investigated the mechanism of the antiatherosclerotic effect of the angiotensin-converting enzyme (ACE) inhibitor, ramipril, in the apolipoprotein (apo) E-deficient mice. Mice that received a high dose (5 mg/kg/day) of ramipril supplemented in their drinking water for 10 weeks showed reduced aortic lesion size by 75% compared with placebo-treated mice. At this dosage, ramipril significantly reduced blood pressure from 95+/-5 mm Hg before treatment to 68+/-4 mm Hg at the end of the treatment period. Ramipril also increased the resistance of the mouse low-density lipoprotein (LDL) to CuSO4-induced oxidation, as shown by a prolongation of the lag time required for the initiation of LDL oxidation from 90 min in the placebo-treated mice to >180 min in the ramipril-treated mice. Similarly, a reduction in the maximal LDL-associated conjugated dienes after 180 min of oxidation by 250% in comparison with placebo-treated mice was noted. Ramipril (1 mg/kg/day) that was still adequate to reduce their plasma ACE activity and LDL propensity to lipid peroxidation was insufficient to reduce their blood pressure. This dosage also inhibited the progression of atherosclerosis in the apo E-deficient mice by 74%. The contribution of bradykinin potentiation to the ACE-inhibitor action was assessed by cotreatment of ramipril with the bradykinin B2-receptor antagonist, icatibant (HOE-140, 0.5 mg/kg given subcutaneously twice a day) for a period of 10 weeks. HOE-140 had no effects on ACE activity, LDL lipid peroxidation, blood pressure, or atherosclerosis. In combination with ramipril, no additional effect of HOE-140 on LDL oxidation or on atherosclerosis was noted in comparison with ramipril treatment alone. We thus conclude that the antiatherogenic effect of ramipril in E(0) mice is independent of blood pressure reduction and is not mediated by bradykinin. It seems, therefore, that most of its antiatherosclerotic and antioxidative effects are mediated through the inhibition of angiotensin II production.
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PMID:Attenuation of atherosclerosis in apolipoprotein E-deficient mice by ramipril is dissociated from its antihypertensive effect and from potentiation of bradykinin. 1063 Jul 34

Experimental and epidemiological evidence suggests that activation of the reninangiotensin-aldosterone system and oxidative modification of low density lipoprotein cholesterol both play important roles in atherosclerosis. A substudy of the HOPE (Heart Outcomes Prevention Evaluation) trial, the SECURE trial (Study to Evaluate Carotid Ultrasound changes in patients treated with Ramipril and vitamin E), evaluated the effects of long-term treatment with the angiotensin-converting enzyme (ACE) inhibitor, ramipril, and with vitamin E on atherosclerosis progression in high risk patients. A total of 732 patients were enrolled into the study. These patients were 55 years or older, had vascular disease or diabetes with at least one other cardiovascular risk factor, but did not have heart failure or low ejection fraction. Patients were randomly assigned according to a three-by-two factorial design to receive placebo, ramipril 2.5 mg/day or ramipril 10 mg/day and placebo or vitamin E 400 IU/day. Progression of atherosclerosis was evaluated by B-mode carotid ultrasonography. The primary outcome evaluated was the annualised progression slope of the mean maximum carotid intimal-medial thickness (IMT) across 12 pre-selected carotid arterial segments. The average follow-up was 4.5 years. The progression slope of the mean maximum IMT was 0.0217 +/- 0.04 mm/year in the placebo group, 0.018 +/- 0.44 mm/year in the ramipril 2.5 mg/day group and 0.0137 +/- 0.04 in the ramipril 10 mg/day group (P = 0.33 for the overall effect of ramipril and P = 0.028 for the comparison between patients receiving ramipril placebo and ramipril 10 mg/day). The reduction in atherosclerotic progression observed with ramipril remained significant after adjusting for systolic and diastolic blood pressure changes (P = 0.043) and after multivariate adjustment (P = 0.046). Administration of vitamin E 400 IU/day had no impact on atherosclerosis progression. The SECURE study is the first demonstration, in human subjects, of an effect of ACE inhibition on atherosclerotic progression. This benefit cannot be explained by the lowering of blood pressure alone. Vitamin E 400 IU/day had a neutral effect on the ultrasound measurements of atherosclerosis progression in the SECURE trial.
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PMID:Modifying the natural history of atherosclerosis: the SECURE trial. 1171 53

Proven cardiovascular benefit from angiotensin-converting enzyme (ACE) inhibition is a cornerstone of evidence-based medicine. The first study to show dramatic benefits from ACE inhibition was the Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS-I), in which a 31% decrease in the rate of death was observed in patients with severe heart failure at the end of 1 year of enalapril treatment (p = 0.001). This result led to large long-term studies-including Survival and Ventricular Enlargement (SAVE), Acute Infarction Ramipril Efficacy (AIRE), Trandolapril Cardiac Evaluation (TRACE), and Study of Left Ventricular Dysfunction (SOLVD)-which verified that ACE inhibition decreases heart failure, myocardial infarction (MI), and mortality, and that striking benefit could be observed within 30 days. Short-term studies of patients in the acute phase of a heart attack verified that ACE inhibition provided rapid benefits. A meta-analysis of short-term (up to 8 weeks) studies of ACE inhibition (including CONSENSUS-II, Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico [GISSI]-3, International Study of Infarct Survival [ISIS]-4, and the Chinese Captopril Study [CCS]-1) demonstrated that post-MI risk was reduced by 10% within the first day of treatment. The immediacy of the benefit suggested that ACE inhibition not only improved cardiovascular function in failing hearts but also affected important mechanisms in patients without overt heart failure. Effects on more general mechanisms of heart disease suggested that patients with problems other than hypertension or heart failure might benefit from ACE inhibitors. The Heart Outcomes Prevention Evaluation (HOPE) study investigated the hypothesis that ACE inhibition would confer benefits to patients who were at high risk for cardiovascular events, but who were without left ventricular dysfunction or heart failure. Long-term reductions in MI, stroke, cardiac arrest, and heart failure, as well as improvements in mortality, were observed in this population after treatment with ACE inhibitors. Substudies of the HOPE study revealed that ACE inhibition reduced progression of atherosclerosis and improved myocardial remodeling. Taken together, these studies provide evidence that supports treatment of a broad population of patients at risk for cardiovascular events with ACE inhibitors. The next step is to combine ACE inhibition with other treatments to maximize patient benefit. The Ongoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET) will compare the efficacy of an ACE inhibitor (ramipril) with an angiotensin receptor blocker (telmisartan), and determine whether these treatments in combination will further reduce morbidity and mortality from cardiovascular disease.
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PMID:Angiotensin II and trials of cardiovascular outcomes. 1183 5

The Heart Outcomes Prevention Evaluation (HOPE) study conclusively demonstrated that ramipril, an angiotensin-converting enzyme (ACE) inhibitor, reduces the risk of cardiovascular death, myocardial infarction (MI), and death in patients at risk for cardiovascular events but without heart failure. The Study to Evaluate Carotid Ultrasound Changes in Patients Treated with Ramipril and Vitamin E (SECURE) substudy demonstrated that ramipril also reduced atherosclerosis. These results suggest that the renin-angiotensin system (RAS) has a more important role in the development and progression of atherosclerosis than previously believed, and they indicate the need for further clinical studies to define the range of benefits available from modifying the RAS. Achieving maximum benefit may require treatment with both an ACE inhibitor and an angiotensin II type-1 receptor blocker (ARB). The Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) study indicated that combining an ACE inhibitor with an ARB decreased blood pressure and improved the ejection fraction more than treatment with either drug alone in patients with congestive heart failure. The Valsartan in Heart Failure Trial (Val-HeFT) showed that the combination of an ACE inhibitor and an ARB reduced hospitalization for heart failure in patients with congestive heart failure by 27.5%, although no decrease in all-cause mortality was observed. The Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET) is a large, long-term study (23,400 patients, 5.5 years). It will compare the benefits of ACE inhibitor treatment, ARB treatment, and treatment with an ACE inhibitor and ARB together, in a study population with established coronary artery disease, stroke, peripheral vascular disease, or diabetes with end-organ damage. Patients with congestive heart failure will be excluded. In a parallel study, patients unable to tolerate an ACE inhibitor will be randomized to receive telmisartan or placebo (the Telmisartan Randomized Assessment Study in ACE-I Intolerant Patients with Cardiovascular Disease [TRANSCEND]). The primary endpoint for both trials is a composite of cardiovascular death, MI, stroke, and hospitalization for heart failure. Secondary endpoints will investigate reductions in the development of diabetes mellitus, nephropathy, dementia, and atrial fibrillation. These 2 trials are expected to provide new insights into the optimal treatment of patients at high risk of complications from atherosclerosis.
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PMID:From the HOPE to the ONTARGET and the TRANSCEND studies: challenges in improving prognosis. 1183 7

Experimental and clinical evidence suggest that angiotensin converting enzyme (ACE) inhibition may reduce cardiovascular (CV) risk by directly affecting endothelial dysfunction, atherosclerosis and thrombus formation. These direct effects are in addition to effects on vascular tone or pressure. The Health Outcomes and Prevention Evaluation (HOPE) study assessed the role of an ACE inhibitor ramipril in reducing CV events in 9297 patients > or = 55 years who were at high risk of CV events but did not have left ventricular dysfunction, heart failure, or high blood pressure at the time of study entry. In the overall HOPE population, the risk of the primary composite outcome (cardiovascular death, myocardial infarction, or stroke) was reduced by 22% (p < 0.001), and in patients with diabetes plus one other CV risk, it was reduced by 25% (p = 0.0004). Ramipril treatment achieved risk reduction in patients with mild renal insufficiency (serum creatinine > or = 1.4 mg/dl). Ramipril treatment did not increase adverse events in patients with renal insufficiency. The Study to Evaluate Carotid Ultrasound changes in patients treated with Ramipril and Vitamin E (SECURE) demonstrated that ramipril 10 mg significantly reduced the rate of carotid intimal medial thickening, suggesting a direct effect on atherosclerotic progression.
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PMID:What should the role of ACE inhibitors be in the treatment of diabetes? Lessons from HOPE and MICRO-HOPE. 1184 51

Foam cell formation, the hallmark of early atherosclerosis, results from cholesterol accumulation in arterial macrophages. Angiotensin-II stimulates foam cell formation and angiotensin converting enzyme (ACE) inhibitors reduce atherosclerosis in animal models. The goal of the present study was to determine the effect of the ACE inhibitor Ramipril on the progression of atherosclerosis in apolipoprotein-E-deficient (E0) mice with already advanced atherosclerosis. Therefore, 4-month-old atherosclerotic E0 mice were treated with Ramipril for 2 and 4 months and compared to age-matched placebo-treated mice, as well as to control young (4-month-old) non-treated E0 mice, for their atherosclerosis. Histomorphometry showed that Ramipril treatment substantially inhibited atherogenesis as shown by 48 and 72% reduction in lesion size at 6 and 8 months of age, respectively, compared to the lesion size in age-matched placebo-treated mice. Moreover, the size of the atherosclerotic lesions in 6- and 8-month-old Ramipril-treated mice was almost identical to the size of atherosclerosis of the 4-month-old control mice. Moreover, Ramipril treatment of E0 mice, significantly reduced oxidized low-density lipoprotein (Ox-LDL) uptake by their peritoneal macrophages (MPM) by 32%, compared to Ox-LDL uptake by MPM from 6-month-old placebo mice, and even reduced it by 12% in comparison to Ox-LDL uptake by MPM from 4-month-old control mice. A significant decrease in the mRNA levels of the Ox-LDL receptor CD36 by 58% was observed in macrophages from 6-month-old Ramipril-treated mice compared to macrophages from the 6-month-old placebo-treated mice. There was even a significant reduction (by 32%) in CD36 mRNA levels in macrophages from the 6-month-old Ramipril-treated mice, compared to the CD36 mRNA levels in macrophages from the 4-month-old control mice. We thus conclude that administration of the ACE inhibitor Ramipril to E0 mice, which already exhibit significant atherosclerosis, blocked the progression of the atherosclerotic lesion build-up, a phenomenon that could be related to Ramipril-induced inhibition of Ox-LDL uptake by macrophages.
Atherosclerosis 2002 Mar
PMID:Ramipril administration to atherosclerotic mice reduces oxidized low-density lipoprotein uptake by their macrophages and blocks the progression of atherosclerosis. 1188 18


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