Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

We have studied serum and lung tissue angiotensin converting enzyme (ACE) activity in female Wistar rats with pulmonary hypertension induced by two different methods. Chronic pulmonary hypertension was produced in one group of 10 rats (CH) by confinement in a hypobaric chamber (380 mmHg) for three weeks, and in another group fo 10 rats (M) by a single subcutaneous injection of monocrotaline (60 mg/kg body weight). In these two groups of tests rats and in 20 untreated controls (C), we evaluated right ventricular mean systolic blood pressure (Prvs mmHg), right ventricular hypertrophy, and serum ACE (n mol/ml/min). In lung tissue homogenate, we measured the specific activity of ACE (n mol/mg protein/min), alkaline phosphatase (AP) (IU/mg protein) and lactic dehydrogenase (LDH) (IU/mg protein). The Prvs in groups, C, CH, and M was 25 +/- 7 SD, 41 +/- 7, and 51 +/- 5, respectively. The ratio of right ot left ventricular weight (RV/(LV + S)%) in groups, C, CH, and M was 29 +/- 4, 52 +/- 5, and 56 +/- 7, respectively. The lung tissue ACE in groups C, CH, and M was 85 +/- 11, 65 +/- 20, and 22 +/- 5, respectively. In groups CH, and M the Prvs and RV/(LV + S)% were significantly elevated above control values while lung ACE was significant decreased (p less than 0.05). There was a significant inverse relationship between lung ACE on one hand, and Prvs (r = - 0.73) and RV/(LV + S)% (r = - 0.71) on the other hand. Serum ACE and lung AP were unchanged. In group M there was a slight but significant reduction in lung LDH. Chronic pulmonary hypertension, irrespective of its method of production, is associated with decreased lung ACE. The reduction in lung ACE is inversely proportional to the severity of pulmonary hypertension and right ventricular hypertrophy.
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PMID:Lung angiotensin converting enzyme activity in rats with pulmonary hypertension. 628 42

Although angiotensin converting enzyme (ACE) inhibitors are known to attenuate the development of hypoxic pulmonary hypertension in rats, the precise mechanism of this protective effect remains unknown. Thus we utilized specific angiotensin II (ANG II)-receptor antagonists to investigate whether ANG II is involved directly in the hemodynamic and structural changes of pulmonary hypertension, and we tested whether the protective effects of ACE inhibition can be attributed partly to potentiation of bradykinin. During 14 days of hypobaric hypoxia, rats received, via intraperitoneal osmotic minipumps, either 1) the ACE inhibitor captopril, 2) captopril plus the bradykinin B2-receptor antagonist CP-0597, 3) the ANG II type 1 receptor antagonist losartan, 4) the ANG II type 2 receptor antagonist PD-123319, or 5) saline. At 14 days, mean pulmonary arterial pressure (MPAP) was reduced (P < 0.05) in hypoxic rats treated with captopril (26.6 +/- 0.8 mmHg) or losartan (24.4 +/- 1.0 mmHg) compared with saline (32.0 +/- 1.4 mmHg) but was unaffected by PD-123319 (29.5 +/- 1.7 mmHg). Right ventricular hypertrophy was reduced in hypoxic rats treated with captopril or losartan compared with saline-treated rats. Morphometry showed less medial thickening and peripheral muscularization of small pulmonary arteries in hypoxic animals treated with captopril or losartan. Coadministration of CP-0597 did not reverse the protective effects of captopril on pulmonary vascular remodeling. These results suggest a novel role for endogenous ANG II, acting through the type 1 receptor, in the vascular remodeling associated with hypoxic pulmonary hypertension. The beneficial effects of ACE inhibition in this model can be attributed to reduced ANG II production rather than potentiation of bradykinin.
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PMID:Role of angiotensin-converting enzyme and angiotensin II in development of hypoxic pulmonary hypertension. 748 48

To investigate the contribution of a cardiac renin-angiotensin system to cardiac hypertrophy due to volume overload, the effects of losartan, a non-peptide angiotensin (Ang) II type 1 (AT1) receptor antagonist on left ventricular hypertrophy (LVH) was studied. LVH was produced in male Wistar rats by volume overload secondary to aortic insufficiency (AI). Losartan (10 mg/kg/d) was orally administered for 2 weeks after surgery to both AI and sham-operated (control) rats. Two weeks after surgery, aortic pulse pressure and left ventricular (LV) weight were markedly increased in the AI rats as compared with the control group, whereas cardiac angiotensin converting enzyme (ACE) activity remained unchanged. The effects of the chronic administration of losartan an AT1 receptors were verified by the blockade of Ang II pressor response. Losartan treatment produced a significant reduction in LVH in AI rats without affecting the systolic blood pressure. In separate groups of rats, to elucidate the mechanisms of the attenuation of LVH by treatment with losartan, we determined plasma and LV immunoreactive Ang II content and plasma renin activity (PRA). LV Ang II content increased in AI rats, while plasma Ang II content, PRA and II concentration were increased by the treatment. There was a significant positive correlation between LV weight and LV Ang II content. These results suggest that cardiac Ang II, rather than circulating Ang II, plays an important role in the LVH due to volume overload via the AT1 receptor.
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PMID:Effects of losartan, an angiotensin II antagonist, on the development of cardiac hypertrophy due to volume overload. 749 86

From pharmacological 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 only by interference with the renin angiotensin system (RAS) by means of an inhibition of angiotensin II (ANG II) formation. Since ACE is identical to kininase II, which inactivates the nonapeptide bradykinin (BK) and related kinins, potentiation of kinins might be responsible for these additional effects of ACE inhibitors. a) In rats made hypertensive by aortic banding, the effect of ramipril in left ventricular hypertrophy (LVH) was investigated. Ramipril in the antihypertensive dose of 1 mg/kg/day for 6 weeks prevented the increase in blood pressure and the development of LVH. The low dose of ramipril (10 micrograms/kg/day for 6 weeks) had no effect on the increase in blood pressure or on plasma ACE activity but also prevented LVH after aortic banding. The antihypertrophic effect of the higher and lower doses of ramipril, as well as the antihypertensive action of the higher dose of ramipril, was abolished by coadministration of the kinin receptor antagonist icatibant. In the regression study the antihypertrophic actions of ramipril were not blocked by the kinin receptor antagonist. Chronic administration of BK had similar beneficial effects in a prevention study which were abolished by icatibant and NG-nitro-L-arginine (L-NNA). In a one year study the high and low dose of ramipril prevented LVH and fibrosis. Ramipril had an early direct effect in hypertensive rats on the mRNA expression for myocardial collagen I and III, unrelated to its blood pressure lowering effect.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Angiotensin converting enzyme inhibitors, left ventricular hypertrophy and fibrosis. 749 60

Based on the epidemiologic data of the Framingham heart study, arterial hypertension and coronary artery disease are the most frequent etiologic factors for the development of heart failure. In the pressure overloaded heart, hypertrophic growth of the myocardium includes the enlargement of cardiac myocytes stimulated by ventricular loading. Non-myocyte cell growth involving cardiac fibroblasts may also occur but is not primarily regulated by the hemodynamic load. Cardiac fibroblast activation is responsible for the accumulation of fibrillar type I and type III collagens within the interstitium while vascular smooth muscle cell growth accounts for the medial thickening of resistance vessels. This remodeling of the cardiac interstitium represents a major determinant of pathological hypertrophy in that it accounts for abnormal myocardial stiffness and impaired coronary vasodilator reserve, leading to ventricular diastolic and systolic dysfunction and ultimately to the appearance of symptomatic heart failure. Several lines of evidence suggest that the renin-angiotensin-aldosterone system is involved in regulating the structural remodeling of the nonmyocyte compartment, including the cardioprotective effects of angiotensin converting enzyme (ACE) inhibition that was found to prevent myocardial fibrosis in the rat with renovascular hypertension. In rats with genetic hypertension, established left ventricular hypertrophy, abnormal diastolic stiffness due to interstitial fibrosis, and reduced coronary vasodilator reserve associated with medial wall thickening of intramyocardial resistance vessels, the ACE inhibitor lisinopril was able to restore myocardial structure and function to normal. These cardioreparative properties of ACE inhibition may be valuable in reversing left ventricular dysfunction in hypertensive heart disease.
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PMID:[Cardiac structure-function relationship and the renin-angiotensin-aldosterone system in hypertensive heart disease]. 749 80

It is well known that, in patients with essential hypertension, left ventricular hypertrophy (LVH) is an independent risk factor for cardiovascular disease. However, it has been demonstrated that normalisation of arterial pressure, by therapy with antihypertensive drugs, is associated with regression of LVH, although the extent and time-course of this phenomenon depend on the antihypertensive drug used. In particular, angiotensin converting enzyme (ACE) inhibitors seem capable of inducing a faster and more complete reversal of LVH in patients with essential hypertension than other antihypertensive drugs. The mechanisms underlying this property of ACE inhibitors remain unclear, although 2 features of ACE inhibitors may be particularly relevant. The first is their ability to improve large artery compliance, this being a major determinant of LVH. Arterial compliance is reduced in essential hypertension, resulting in increased left ventricular end-systolic stress, which then contributes to the development of LVH. The second possible mechanism by which ACE inhibitors reverse LVH to a greater degree than other antihypertensive drugs may relate to their ability to interfere with the cardiopulmonary receptor control of the circulation. Thus, ACE inhibitors may counteract the neural and hormonal abnormalities that contribute to the maintenance of LVH in hypertensive patients.
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PMID:Effects of angiotensin converting enzyme inhibitors on left ventricular hypertrophy. 751 89

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

The aim of the investigation was to assess and compare the effects of a calcium channel antagonist, (i.e. amlodipine) and an ACE-inhibitor (i.e. lisinopril) in reducing chronic left ventricular hypertrophy in 15-week old spontaneously hypertensive rats (SHR). Changes in cardiac hypertrophy were assessed after 8 weeks by measuring the fractional rates of protein synthesis using a 'flooding dose' of [3H]-phenylalanine for 10 min. Blood pressure was monitored throughout the treatment period in both SHR and Wistar-Kyoto control rats (WKY). The results showed a decrease in blood pressure by amlodipine after 1 week of treatment which was further reduced at 4 to 8 weeks. Lisinopril caused immediate and sustained reductions in blood pressure (190 mmHg to 130 mmHg, P < 0.001). After 8 weeks of treatment in SHR rats, amlodipine had no significant effect on left ventricular weight (P > 0.05), whereas lisinopril caused a marked reduction. The protein content and RNA were also not changed by amlodipine. In contrast, lisinopril significantly lowered the tissue protein, RNA and DNA content (P < 0.001). The changes in the left ventricles of lisinopril-treated SHR rats were accompanied by an increase in the fractional synthesis rate of left ventricular myofibrillar proteins (+12 per cent, P < 0.025). The synthesis rate per unit RNA was also increased in right ventricular tissue of lisinopril-treated SHR rats. However, amlodipine had no effect on the fractional synthesis rates of any of the left-ventricular fractions of SHR rats (P > 0.05). The cellular efficiency in the right ventricle was also increased in amlodipine-treated SHR rats, indicating a moderate effect on protein metabolism. In conclusion, amlodipine had minimal effects in the reduction of established left ventricular hypertrophy (LVH), despite reducing the blood pressure, whereas lisinopril caused regression of LVH. These events were associated with small changes in protein synthesis rates, with the contractile protein showing an increase.
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PMID:Protein synthesis in the hypertrophied heart of spontaneously hypertensive rats and a comparison of the effects of an ACE-inhibitor and a calcium channel antagonist. 753 13

Future directions in antihypertensive treatment will rely on our present experience with antihypertensive drugs, on new concepts of cardiovascular regulation and on novel antihypertensive agents. At present, we seek early detection of hypertension; treatment should focus on normalization of blood pressure, the reversal or prevention of left ventricular hypertrophy, associated coronary artery disease and on the prevention of, or reparation of, myocardial fibrosis and microangiopathy. Therefore, combination therapy is advisable in severe cases, and any monotherapy should focus on the pharmacological principles compatible with these goals. ACE inhibitors and calcium antagonists appear to meet these requirements. There are, in addition, novel drugs i.e. angiotensin II receptor antagonists and renin inhibitors, as well as therapeutic stimulation of endothelial nitric oxide by L-arginine, the inhibition of endothelin-1 mediated vasoconstriction, and potassium-channel openers. All are examined in this contribution to delineate the perspectives in antihypertensive therapy.
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PMID:Directions in antihypertensive treatment--our future from the past. 755 77

In genetic and acquired hypertension, a structural remodeling of the nonmyocyte compartment of myocardium, including the accumulation of fibrillar collagen and other components of the extracellular matrix (ECM) within the interstitium, represents a determinant of pathologic hypertrophy that leads to ventricular dysfunction. Therefore, to evaluate the potential benefit of the angiotensin converting enzyme (ACE) inhibitor quinapril in reversing the interstitial remodeling in spontaneously hypertensive rats (SHR) with established left ventricular hypertrophy (LVH), we treated 16-week-old male SHR with oral quinapril (average dose, 10 mg/kg body weight/day) for 20 weeks. Interstitial fibrosis was determined morphometrically using an automatic image analyzer. The amount of collagen was evaluated by measuring myocardial hydroxyproline concentration. Myocardial deposition of collagen molecules (types I, III, and IV) and other ECM components (fibronectin, laminin) was analyzed by immunohistochemical techniques using specific monoclonal antibodies. The activity of ACE was measured in left ventricular tissue by a fluorometric assay. In quinapril-treated SHR compared with 36-week-old untreated SHR and age- and sex-matched Wistar-Kyoto (WKY) controls, we found 1) a lesser degree of LVH and a lesser level of blood pressure, 2) a lesser degree of interstitial fibrosis, represented by less interstitial collagen volume fraction (5.73 +/- 0.45% v 3.42 +/- 0.28%, P < .05; WKY, 3.44 +/- 0.66%), 3) a lower hydroxyproline concentration (1.09 +/- 0.05 mumol/L/g dry weight/100 g body weight to 0.81 +/- 0.05 mumol/L/g dry weight/100 g body weight, P < .05; WKY, 0.96 +/- 0.06 mumol/L/g dry weight/100 g body weight), 4) a lesser presence of collagen fibers, and 5) a lesser presence of collagen IV, fibronectin, and laminin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Quinapril decreases myocardial accumulation of extracellular matrix components in spontaneously hypertensive rats. 757 98


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