Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.15.1 (ACE)
 18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of various antihypertensive medications on platelet function is of increasing interest. Conflicting effects of captopril on platelet function are reported and the impact of angiotensin converting enzyme (ACE) inhibitors not containing a sulfhydryl group such as enalapril, lisinopril, and quinapril on platelet function remains unstudied. Therefore, the aim of the present study was to examine the effect of antihypertensive treatment with quinapril, a novel ACE inhibitor not containing a sulfhydryl group, on platelet function. Ten white men (age range of 32-61 years) with untreated mild-to-moderate essential hypertension (supine diastolic blood pressure greater than 95 mm Hg) were treated with 4 weeks each of placebo and quinapril in a double-blind, randomized, crossover design. Quinapril (20 mg twice a day) significantly lowered systolic (p less than 0.01) and diastolic blood pressure (p less than 0.01) without any significant effect on heart rate or plasma catecholamines. No significant change was noted for in vitro platelet aggregation induced by epinephrine, ADP, or collagen. Plasma concentrations of the platelet release factors beta-thromboglobulin and platelet factor 4 did not change, nor did the platelet content of norepinephrine, platelet weight (mg/10 ml of blood), circulating platelet count, or platelet size. Thus, as assessed by a broad spectrum of platelet parameters, we found that antihypertensive treatment with quinapril has no significant effect on platelet function in patients with mild-to-moderate essential hypertension. These "platelet-neutral" properties of quinapril suggest that quinapril, both from a thromboembolic and a hemostatic point of view, may be a rather safe agent for treatment of hypertension.
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PMID:Platelet function during antihypertensive treatment with quinapril, a novel angiotensin converting enzyme inhibitor. 170 46

The renin-angiotensin system is the major contributor to development of hypertension, atherosclerosis, and many other cardiovascular diseases. Angiotensin II, one of the main effectors of this system, contributes to the pathogenesis of hypertension and plays an important role in monocyte, platelet, and endothelium interactions. The effects on platelet and endothelial function, either by angiotensin converting enzyme inhibitors or angiotensin receptor antagonists, are still not well understood. A double-blind, randomized, prospective trial of either enalapril (10-20 mg daily) or eprosartan (400-800 mg daily) over a 10-week period was conducted in 42 patients (27 males, 15 females). Platelet activation was evaluated by measuring platelet factor 4 (PF-4), beta-thromboglobulin (beta-TG), the ratio of platelet factor 4 to beta-thromboglobulin, and endothelial function by measuring total plasma nitrate levels, von Willebrand factor (vWF) levels, and blood flow using venous occlusive plethysmography. After a 10-week treatment with enalapril or eprosartan, the sitting blood pressure in both the enalapril group (from 152.2 +/- 18.7 mmHg to 141.9 +/- 23.5 mmHg, P < 0.05) and eprosartan group (from 151 +/- 10.0 mmHg to 142.3 +/- 12.9 mmHg, P < 0.05) was significantly reduced. Significant diastolic blood pressure (DPB) reduction (from 94 +/- 8.7 to 84.5 +/- 9.6 mmHg, P < 0.05) and a greater DBP reduction response were found in the eprosartan group (63% in eprosartan versus 25% in enalapril). Additionally, dose-dependent reductions in the indices of platelet activation and endothelial dysfunction were observed in patients administered high dose treatments of eprosartan and enalapril, and the beneficial effects of these agents were not correlated with the reduction of blood pressure using both agents. Eprosartan is effective and well-tolerated in the treatment of mid-to-moderate hypertension, and the DBP response reduction to eprosartin was better than that to enalapril. A high dose of either eprosartan or enalapril significantly decreased the indices of platelet activation and endothelial dysfunction in hypertensive patients. The benefits of both agents cannot be explained solely by their antihypertensive effects and possibly may be mediated through their unique effect on angiotensin blockade.
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PMID:A double blind randomized trial to compare the effects of eprosartan and enalapril on blood pressure, platelets, and endothelium function in patients with essential hypertension. 1535 73

Platelet aggregation using a single platelet counting technique in whole blood, was determined on 18 patients with primary Raynaud's phenomenon and 17 age-matched controls. Platelet aggregation in the Raynaud's patients was also assessed during a double-blind, crossover trial to investigate the efficacy of the angiotensin converting enzyme (ACE) inhibitor, enalapril. There were no differences in platelet aggregation to collagen, arachidonic acid, ADP or PAF, or in plasma levels of beta-thromboglobulin (BTG), platelet factor 4 (PF4) or thromboxane B(2) (TxB(2)) between the Raynaud's group and the normal controls. Similarly, there were no differences in these parameters in the Raynaud's group during treatment with enalapril when compared to placebo. It is concluded that patients with primary Raynaud's phenomenon have no evidence of abnormal platelet aggregation or increased platelet activation, and that platelet aggregation is not affected by enalapril.
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PMID:Platelet Aggregation in Primary Raynaud's Phenomenon and the Effect of Enalapril Administration. 2104 82