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

The combination of morphological atherosclerotic alterations of coronary vessels and disturbance of coronary vasomotor control of epicardial and resistance vessels determines the amount of myocardial oxygen supply. The endothelium plays a crucial role for functional alterations of the coronary vessels in patients with early atherosclerosis or risk factors for coronary artery disease. A therapy which aims to ameliorate endothelium-dependent vasodilator capacity improves myocardial perfusion in patients with coronary artery disease. Thereby, even in patients with angiographically normal or minimally diseased coronary vessels who develop myocardial ischemia due to microvascular disease, symptomatic improvement might be achieved. Control of coronary vasomotor tone and proliferation processes within the vessel wall are both determined by the redox equilibrium of nitric oxide (NO) and superoxide radicals (O2-), induced by angiotensin II. Thus, vasomotor control and vessel wall proliferation is closely related to each other. Aim of a therapeutic intervention to enhance NO bioactivity is either to increase NO production in the endothelium or to decrease O2- production, which rapidly inactivates NO. NO bioactivity can be ameliorated by ACE-inhibitors, increase of shear stress on the endothelium by physical exercise, estrogens or L-arginine. For these therapies clinically an improvement of endothelial vasodilator function could be shown. In addition, improvement of endothelial vasodilator function can be achieved by a treatment which reduced oxidative stress in the vascular wall such as antioxidants and, especially, lipid lowering drugs. Endothelin-antagonists and angiotensin II receptor-blockers are promising to improve endothelial dysfunction. However, these therapies have to be validated. Most therapy strategies, which have shown to ameliorate endothelial dysfunction, are also able to improve prognosis of the patients. Whether endothelial dysfunction alone--without evidence of overt coronary atherosclerosis--is sufficient to justify a long-term therapy to improve prognosis, still has to be clarified.
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PMID:[Therapeutic options for improvement of myocardial perfusion in coronary atherosclerosis]. 959 7

Hemodynamic and non-hemodynamic factors contribute to the development of left ventricular hypertrophy (LVH). The presence of LVH is an important independent risk factor for total mortality and for cardiovascular morbidity and mortality. Direct cardiac effects of LVH include an increased risk of developing of congestive heart failure, an increased risk of arrhythmic events, and a reduced coronary flow reserve, promoting myocardial ischemic episodes. In addition, hypertension may promote the development of coronary artery atherosclerosis. The prognostic implications of LVH underscore the importance of diagnostic procedures. The electrocardiogram has a high specificity to identify patients with LVH but the sensitivity is fairly low. Echocardiography provides higher sensitivity and also gives important information, such as the pattern of left ventricular geometry, which is of prognostic importance, and the presence of diastolic dysfunction, which is an early abnormality in the evolution of hypertensive LVH. Reversal of LVH appears to improve prognosis. Reduction of blood pressure is one important component in the regression of LVH. Important quantitative differences exist between drug classes in the reversal of cardiac hypertrophy despite similar antihypertensive effects, suggesting other factors to be of importance in the regression of left ventricular mass. LVH is reduced more by angiotensin-converting enzyme inhibitors than by other antihypertensive drug classes, suggesting an effect on structural myocardial changes beyond that provided by the reduction of blood pressure. Recent data suggest that angiotensin II receptor antagonists (AIIRAs) have quantitatively similar effects on left ventricular mass as do angiotensin-converting enzyme inhibitors. A comparative trial of the AIIRA irbesartan and the beta-blocker atenolol demonstrated that despite similar reductions in blood pressure, the reductions attained in left ventricular mass with irbesartan were progressive and numerically greater than those attained with atenolol. Taken together, these findings provide circumstantial evidence for an important role of angiotensin II acting on angiotensin type 1 (AT1) receptors in the development or maintenance of cardiac hypertrophy. Confirmation of the favorable effects of angiotensin-converting enzyme inhibitors and AIIRAs on left ventricular mass in larger trials, including those assessing cardiovascular morbidity and mortality, will be of major importance in the future treatment of hypertension.
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PMID:The importance of left ventricular hypertrophy in human hypertension. 985 28

Angiotensin converting enzyme (ACE) inhibitors reduce the development of atherosclerosis in hypercholesterolemic animals across a wide range of species. Although the mechanism for these effects has not been well delineated, it has been assumed generally that both angiotensin II suppression and interference with the breakdown of bradykinin are involved. To determine whether angiotensin II receptor blockade provides similar effects as those observed with ACE inhibition, we examined the influence of irbesartan, an AT1 receptor antagonist, on aortic atherosclerosis in Watanabe heritable hyperlipidemic rabbits using the identical protocol that was employed in our earlier studies involving ACE inhibitors. At a dose of irbesartan (30 mg/kg/day), which was selected because it appeared to block most of the pressor effects of infused angiotensin in rabbits, no effect on atherosclerosis was observed. However, a higher dose of irbesartan (75 mg/kg/day) caused reductions in blood pressure and aortic atherosclerosis similar to those seen in earlier studies with ACE inhibitors. The decrease in aortic intimal surface involvement with irbesartan was from 38.9 +/- 3.8% in controls to 24.1 +/- 3.0% in the treated group (P < .01). Aortic cholesterol content was also significantly reduced in those animals (P < .02). The findings indicate that suppression of the renin-angiotensin system by AT1 receptor blockade in a genetically hypercholesterolemic rabbit model causes comparable inhibition of aortic atherosclerosis as that achieved by ACE inhibition, and that a mild reduction of blood pressure induced by both classes of agents may contribute to their antiatherosclerotic action in this model.
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PMID:Comparison of the effects of AT1 receptor blockade and angiotensin converting enzyme inhibition on atherosclerosis. 1007 81

Many of hypertensive individuals have glucose intolerance, dyslipidemia and hyperuricemia. It is important to take care of these metabolic disease for not only the progression hypertension itself but also the prevention of atherosclerosis. We reviewed the effects of angiotensin II receptor antagonists on glucose, lipid, and uric acid metabolism in essential hypertensives.
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PMID:[The effects of angiotensin II receptor antagonists on glucose, lipid, and uric acid metabolism in essential hypertensives]. 1036 47

Many of hypertensive individuals have glucose intolerance and dyslipidemia, and insulin resistance is common disorder on the basis of these diseases. It is important to take care of these metabolic disease for not only the control of hypertension, blood glucose and hyperlipidemia, but also the prevention of atherosclerosis. We reviewed the effects of angiotensin II receptor antagonists on insulin resistant syndrome.
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PMID:[The effects of angiotensin II receptor antagonists on insulin resistance]. 1036 53

Genes that influence the renin-angiotensin system have been investigated in recent years as potential etiologic candidates of cardiovascular and renal diseases. In atheromatous renal artery stenosis (RAS), a condition characterized by persistent activation of the renin-angiotensin system, the study of these genes may be of particular relevance. We evaluated angiotensin-converting enzyme (ACE) insertion/deletion, angiotensinogen (AGT) M235T, and angiotensin II receptor (ATR) A1166C polymorphisms in relation to the occurrence of RAS. We studied 58 patients with angiographically documented RAS; 102 normotensive subjects with normal coronary arteries and no history or clinical or instrumental evidence of atherosclerosis in other vascular districts were considered the control group. Patients had a significantly higher D allele frequency (0.70 versus 0.55; chi(2) 6.88, P=0.01; odds ratio [OR] 1. 9, 95% CI 1.17 to 3.07) than did the control population; 48.3% of patients were homozygous for DD (chi(2) 6.62, P<0.05; OR 2.04, 95% CI 1.05 to 3.95); and only 8.6% carried the II genotype (OR 0.34, 95% CI 0.19 to 1.47). No significant association was found for AGT M235T and ATR A1166C. Our results suggest a predisposing role for ACE genetic polymorphism in the development and progression of atheromatous RAS.
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PMID:Genetic polymorphisms of the renin-angiotensin system and atheromatous renal artery stenosis. 1056 88

High-cholesterol alimentation is associated with an induction of angiotensin-converting enzyme and angiotensin II receptor expression within the vascular wall of the aorta. Despite an enhanced pressure response to angiotensin II in atherosclerotic conscious rabbits, angiotensin II-induced contraction was reduced in isolated vascular rings from the aorta and unchanged in those from the iliac artery. We, therefore, investigated whether cholesterol-induced atherosclerosis enhances overall vascular responsiveness to angiotensin II in intact animals and whether an altered arterial baroreflex sensitivity can explain the discrepancy between experiments in intact animals and isolated blood vessels. Rabbits were maintained on a high-cholesterol diet (2 g/d cholesterol plus 20 mL/d sunflower seed oil, n=11) or on a standard diet (n=12) for 12 weeks. Total serum lipids markedly increased (P<0.05). Tissue examinations 6 weeks after termination of the high-cholesterol diet revealed distinct atherosclerosis and elevated cholesterol content in the aorta (P<0.05). A high-cholesterol diet did not change baseline hemodynamic parameters. However, angiotensin II-induced increases in total peripheral resistance were larger in the atherosclerotic animals (86.3+/-13.0 versus 41.9+/-9.7 mm Hg. L(-1). min, P<0.05). In addition, the blood pressure pulse interval relationship was markedly reduced (slope: 0.80+/-0.14 versus 0. 49+/-0.06 ms/mm Hg, P<0.05), which suggested that the baroreflex blunted the angiotensin II response to a lesser extent in atherosclerotic animals. In conclusion, the overall vascular responsiveness to angiotensin II is increased in the atherosclerotic rabbit as indicated by the larger increase in total peripheral resistance. An attenuation of the arterial baroreflex sensitivity may contribute to this effect.
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PMID:Vascular response to angiotensin II in atherosclerosis: role of the baroreflex. 1067 18

CS-866 is a new angiotensin II receptor blocker that has demonstrated effectiveness for lowering blood pressure in animal models of hypertension. Given the proposed involvement of the renin-angiotensin system in diabetic nephropathy and atherosclerosis, we have tested CS-866 in animal models of these conditions. The renal protective properties of CS-866 were examined in the Zucker diabetic fatty (ZDF) rat, a model of type 2 diabetes that develops progressive hyperglycemia, glomerulosclerosis, and proteinuria. Treatment of ZDF rats with CS-866 in the diet for 19 weeks resulted in a dose-dependent reduction in urinary protein excretion compared with vehicle-treated control rats, which was independent of changes in blood pressure and glycemic state. The antiatherosclerotic properties of CS-866 were tested in 2 animal models. In the first study, cynomolgus monkeys were fed a high-cholesterol diet for 6 months while receiving CS-866 or vehicle. At the end of this period, CS-866-treated animals had 64% less plaque area in the aorta than controls. CS-866 was also tested in the Watanabe heritable hyperlipidemic (WHHL) rabbit model of atherosclerosis. WHHL rabbits were treated for 32 weeks with CS-866 (1 mg/kg), pravastatin (50 mg/kg), a combination of the 2 drugs, or vehicle. CS-866 had no effect on plasma cholesterol levels and reduced blood pressures minimally. Pravastatin alone reduced serum cholesterol but had no effect on blood pressure or lesion area. In contrast, treatment with CS-866 resulted in a 40% reduction in lesion area compared with vehicle-treated control when given alone and a 50% reduction in combination with pravastatin. On the basis of results from animal models, CS-866 may be a useful treatment for diabetic nephropathy and atherosclerosis.
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PMID:New pharmacologic aspects of CS-866, the newest angiotensin II receptor antagonist. 1133 66

Cardiovascular and renal diseases in diabetes stem from an accelerated form of atherosclerosis in both small and large blood vessels. Diabetic nephropathy is a clinical hallmark of microangiopathy and often leads to end-stage renal failure. Significantly, microalbuminuria is an independent predictor of cardiovascular morbidity and mortality in both the diabetic and non-diabetic population. In diabetic patients, it is also strongly associated with proliferative retinopathy, neuropathy and hypertension. Effective blood pressure reduction in patients with type 2 diabetes and diabetic nephropathy is known to reduce albuminuria, delay the progression of diabetic nephropathy, postpone renal failure and improve survival. These benefits have been demonstrated with a variety of blood pressure-lowering agents, including beta-blockers, calcium channel blockers, diuretics and angiotensin-converting enzyme (ACE) inhibitors. Less is known about the renal effects of the newest class of antihypertensive agents, the angiotensin II receptor antagonists (AIIRAs). Irbesartan is an AIIRA that provides antihypertensive efficacy comparable to ACE inhibitors but with superior tolerability. The PRogram for Irbesartan Mortality and morbidity Evaluations (PRIME) is an important morbidity and mortality program encompassing the Irbesartan Diabetic Nephropathy Trial (IDNT) and the IRbesartan MicroAlbuminuria type 2 diabetes mellitus in hypertensive patients (IRMA II) study. PRIME is evaluating the effects of irbesartan in preventing diabetic nephropathy and end-stage renal failure and in reducing cardiovascular events in high-risk hypertensive patients with type 2 diabetes. The trials were completed at the end of 2000.
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PMID:Hypertension and diabetes: the scope of the problem. 1146 14

Numerous prospective studies have shown that high heart rate is related to the development of hypertension, atherosclerosis, and incidence of cardiovascular events. Experimental studies in monkeys have shown that high heart rate has direct atherogenic effects on the arteries as a result of increased wall stress. However, clustering of several risk factors for coronary artery disease in persons with high heart rate suggests that sympathetic overactivity also accounts for part of the increased cardiovascular morbidity that is observed in persons with tachycardia. Indeed, experimental studies have shown that heightened sympathetic tone can cause obesity, hyperinsulinemia, and insulin resistance, which in the long term can promote the development of atherosclerosis. Through its interaction with plasma insulin, sympathetic overactivity can promote the development of left ventricular hypertrophy. Sympathetic activation can also increase hematocrit and precipitate a procoagulant state. Angiotensin II has an effect both on the central nervous system, enhancing sympathetic outflow, and on the peripheral sympathetic nerves. Among the angiotensin II receptor antagonists, eprosartan showed a particular ability to block presynaptic angiotensin II receptor 1 (AT(1)) receptors at neuro-effector junctions in the sympathetic nervous system, as well as AT(1) receptors in blood vessels. This dual action may represent an important advance in treatment of elevated blood pressure.
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PMID:Sympathetic overactivity in hypertension: a risk factor for cardiovascular disease. 1158 Aug 82


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