ramipril and Body-Weight

A retrospective pooled analysis of the 'Prospective, Randomized Investigation of the Safety and Efficacy of MICARDIS vs. Ramipril Using ABPM' studies conducted in Europe and South Africa (PRISMA I) and in the United States of America and Canada (PRISMA II) was carried out to investigate the effects of telmisartan and ramipril on dipper status (extreme dippers, dippers, non-dippers, risers/reverse dippers), and blood pressure (BP) variability in 1279 patients (with normal sleeping patterns and valid 24-h ambulatory BP monitoring recordings at baseline and end point). After 14 weeks' treatment, telmisartan had a greater systolic BP (SBP) reduction and higher smoothness index in all four dipper groups compared with ramipril. In addition, the tendency toward dipping was significantly higher in patients treated with) telmisartan than ramipril (P=0.032; odds ratio for telmisartan vs. ramipril: 1.27 (95% confidence interval: 1.102-1.58)). In patients with an early morning SBP surge 35 mm Hg, telmisartan treatment was associated with significantly greater reductions from baseline in the night-time low mean, early morning mean and early morning SBP surge compared with ramipril (P=0.026, P<0.0001 and P=0.0006, respectively). In this retrospective analysis, telmisartan was shown to normalize the circadian BP pattern to a dipper profile in a larger proportion of patients than ramipril, and reduce early-morning SBP surge in high-risk patients, indicative of a cardioprotective effect. These findings need to be confirmed in long-term prospective trials and observational studies.

Topics: Age Factors; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Benzimidazoles; Benzoates; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Body Mass Index; Body Weight; Circadian Rhythm; Female; Humans; Hypertension; Male; Meta-Analysis as Topic; Middle Aged; Ramipril; Retrospective Studies; Telmisartan

We planned a randomized, double blind clinical trial to evaluate whether an antihypertensive intervention at the proximal or distal level of the renin-angiotensin-aldosterone system could have different effects on a broad range of innovative cardiovascular risk biomarkers. A total of 288 hypertensive Caucasian patients (115 men and 113 women), aged ≥ 18 years, were enrolled in this study. They were randomized to take losartan 50 mg per day or ramipril 5 mg per day for 1 month and titrated up to 100 mg per day and 10 mg per day for 13 months, respectively. At baseline, 1, 2 and 14 months after therapy initiation, we evaluated the following parameters: body weight, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting plasma glucose (FPG), M-value, adiponectin (ADN), resistin (r), retinol binding protein-4 (RBP-4), visfatin, vaspin, high-sensitivity C-reactive protein (Hs-CRP), matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). No variation of body weight, BMI, FPG or vaspin was obtained with either treatment. We recorded a similar improvement in SBP, DBP and Hs-CRP with both treatments; however, losartan also increased M-value, ADN and visfatin, whereas ramipril did not. Furthermore, losartan decreased r, RBP-4, MMP-2 and MMP-9, whereas ramipril did not have any effect on these parameters. In conclusion, we observed that short-term treatment with losartan improved several metabolic parameters (M-value, ADN, RBP-4, r and visfatin) and decreased vascular remodeling biomarkers (MMP-2 and MMP-9) in hypertensive subjects, whereas ramipril did not.

Topics: Adipose Tissue; Adult; Antihypertensive Agents; Biomarkers; Blood Glucose; Blood Pressure; Body Mass Index; Body Weight; Double-Blind Method; Enzyme-Linked Immunosorbent Assay; Female; Glucose Clamp Technique; Humans; Hypertension; Intention to Treat Analysis; Linear Models; Losartan; Male; Middle Aged; Ramipril; Treatment Outcome

Current guidelines for the treatment of hypertension do not provide specific recommendations for obese hypertensive patients. To identify an optimal treatment regimen for obese hypertensive patients, we studied the interactions between a drug-based weight loss approach by sibutramine and different antihypertensive drug regimens.. This was a prospective, 16-week double-blind placebo-controlled randomized multicenter study in 171 obese hypertensive patients. After a 2-week run-in period, patients receiving 1 of the 3 antihypertensive combination therapies (felodipine 5 mg/ramipril 5 mg [n=57], verapamil 180 mg/trandolapril 2 mg [n=55], or metoprolol succinate 95 mg/hydrochlorothiazide 12.5 mg [metoprolol/hydrochlorothiazide; n=59]) were assigned randomly to sibutramine (15 mg) or placebo. Sibutramine treatment resulted in a significantly greater decrease in body weight, body mass index, and waist circumference and a significant increase in diastolic blood pressure during 24-hour blood pressure monitoring compared with placebo treatment. Sibutramine-induced weight loss and reduction of visceral obesity were markedly attenuated in the metoprolol/hydrochlorothiazide group compared with the other groups. Consistently, improvement in glucose tolerance and hypertriglyceridemia by sibutramine was abrogated in the cohort treated with metoprolol/hydrochlorothiazide compared with the other groups.. The present study demonstrates for the first time that an antihypertensive combination therapy regimen with angiotensin-converting enzyme inhibitors and calcium channel blockers is more advantageous than a beta-blocker/diuretic-based regimen in supporting the weight-reducing actions and concomitant metabolic changes induced by sibutramine in obese hypertensive patients. These data may help to develop future comprehensive treatment strategies and guidelines for this high-risk patient population.

Topics: Adult; Aged; Antihypertensive Agents; Appetite Depressants; Blood Pressure; Body Weight; Cyclobutanes; Double-Blind Method; Drug Interactions; Drug Therapy, Combination; Felodipine; Female; Humans; Hydrochlorothiazide; Hypertension; Indoles; Male; Metoprolol; Middle Aged; Obesity; Prospective Studies; Ramipril; Treatment Outcome; Verapamil

To test the hypothesis that the use of an angiotensin-converting enzyme inhibitor (ACEi) during radiotherapy may be ameliorative for treatment-related normal tissue damage, a pilot study was conducted with the clinically approved (ACE) inhibitor ramipril on the outcome of radiation-induced myelopathy in the rat cervical spinal cord model. Female Sprague Dawley rats were irradiated with single doses of either carbon ions (LET 45 keV/μm) at the center of a 6 cm spread-out Bragg peak (SOBP) or 6 MeV photons. The rats were randomly distributed into 4 experimental arms: (i) photons; (ii) photons + ramipril; (iii) carbon ions and (iv) carbon ions + ramipril. Ramipril administration (2 mg/kg/day) started directly after irradiation and was maintained during the entire follow-up. Complete dose-response curves were generated for the biological endpoint radiation-induced myelopathy (paresis grade II) within an observation time of 300 days. Administration of ramipril reduced the rate of paralysis at high dose levels for photons and for the first time a similar finding for high-LET particles was demonstrated, which indicates that the effect of ramipril is independent from radiation quality. The reduced rate of myelopathy is accompanied by a general prolongation of latency time for photons and for carbon ions. Although the already clinical approved drug ramipril can be considered as a mitigator of radiation-induced normal tissue toxicity in the central nervous system, further examinations of the underlying pathological mechanisms leading to radiation-induced myelopathy are necessary to increase and sustain its mitigative effectiveness.

Topics: Animals; Body Weight; Dose-Response Relationship, Radiation; Female; Heavy Ion Radiotherapy; Incidence; Photons; Ramipril; Rats, Sprague-Dawley; Spinal Cord Diseases; Time Factors

Bardoxolone methyl is an antioxidant inflammation modulator acting through induction of Keap1-Nrf2 pathway. Results from a recent phase IIb clinical trial reported that bardoxolone methyl was associated with improvement in the estimated glomerular filtration rate in patients with advanced chronic kidney disease and Type 2 diabetes. However, increases in albuminuria, serum transaminase, and frequency of adverse events were noted. We studied the effect of 3-mo treatment with RTA 405, a synthetic triterpenoid analog of bardoxolone methyl in Zucker diabetic fatty rats with overt Type 2 diabetes. Rats were treated from 3 mo of age with vehicle, RTA 405, ramipril, or RTA 405 plus ramipril. RTA 405 caused severe changes in food intake and diuresis with decline in body weight, worsening of dyslipidemia, and increase in blood pressure. Early elevation in serum transaminase was followed by liver injury. RTA 405 worsened proteinuria, glomerulosclerosis, and tubular damage. Ramipril was renoprotective, but when given with RTA 405 it was not able to limit its worsening effects. These data could be due to degradation products in the drug substance used, as disclosed by the company once the study was concluded. To overcome such a drawback, the company offered to test dh404, a variant of RTA 405, in Zucker diabetic fatty rats. The dh404 did not display beneficial effects on proteinuria, glomerulosclerosis, and interstitial inflammation. Rather, kidneys from three rats receiving dh404 showed the presence of a granulomatous and inflammatory process reminiscent of a pseudotumor. Altogether these data raise serious concerns on the use of bardoxolone analogs in Type 2 diabetic nephropathy.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Body Weight; Chromatography, Liquid; Diabetic Nephropathies; Disease Models, Animal; Diuresis; Drinking; Hemodynamics; Kidney; Liver; Male; Mass Spectrometry; Oleanolic Acid; Ramipril; Rats; Rats, Zucker; Renal Circulation; Triterpenes

We hypothesized that chronic administration of the angiotensin-converting enzyme inhibitor, ramipril, to young adult male rats would prevent/ameliorate fractionated whole-brain irradiation-induced perirhinal cortex-dependent cognitive impairment. Eighty 12-14-week-old young adult male Fischer 344 rats received either: (1) sham irradiation, (2) 40 Gy of fractionated whole-brain irradiation delivered as two 5 Gy fractions/week for 4 weeks, (3) sham irradiation plus continuous administration of 15 mg/L of ramipril in the drinking water starting 3 days before irradiation, or (4) fractionated whole-brain irradiation plus ramipril. Cognitive function was assessed using a perirhinal cortex-dependent version of the novel object recognition task 26 weeks after irradiation. Microglial activation was determined in the perirhinal cortex and the dentate gyrus of the hippocampus 28 weeks after irradiation using the ED1 antibody. Neurogenesis was assessed in the granular cell layer and subgranular zones of the dentate gyrus using a doublecortin antibody. Fractionated whole-brain irradiation led to: (1) a significant impairment in perirhinal cortex-dependent cognitive function, (2) a significant increase in activated microglia in the dentate gyrus but not in the perirhinal cortex, and (3) a significant decrease in neurogenesis. Continuous administration of ramipril before, during, and after irradiation prevented the fractionated whole-brain irradiation-induced changes in perirhinal cortex-dependent cognitive function, as well as in microglial activation in the dentate gyrus. Thus, as hypothesized, continuous administration of the angiotensin-converting enzyme inhibitor, ramipril, can prevent the fractionated whole-brain irradiation-induced impairment in perirhinal cortex-dependent cognitive function.

Topics: Angiotensin I; Angiotensin-Converting Enzyme Inhibitors; Animals; Body Weight; Cerebral Cortex; Cognition Disorders; Cranial Irradiation; Dose Fractionation, Radiation; Doublecortin Protein; Male; Radiation Injuries, Experimental; Ramipril; Rats; Rats, Inbred F344

The ONTARGET trial revealed an association of ACEI/ARB combination treatment (telmisartan and ramipril) with adverse renal outcome versus respective monotherapy; preclinical evidence regarding renal outcome in ACEI/ARB combination treatment is scarce.. Spontaneously hypertensive stroke prone rats (SHR-SP) rats on a salt-rich diet were randomly allocated to 4 groups: SHR (untreated, n = 24), SHR + telmisartan (SHR-T, 2.39 +/- 0.69 mg/kg bw; n = 27), SHR + ramipril (SHR-R, 6.28 +/- 3.48 mg/kg bw; n = 27) and combination treatment (SHR-TR, 0.51 +/- 0.14 mg/kg bw; same dose for telmisartan and ramipril; n = 26). Study duration was 12 weeks, blood pressure was assessed weekly and doses were adjusted to maintain equal blood pressure. Finally, blood and urine samples were obtained and kidneys were harvested for histological studies.. Blood pressure in untreated rats rose to a maximum of 239 mmHg, whereas in all treatment groups it remained stable between 140 and 150 mmHg. Mortality was 50% in the untreated group, whereas all treatment groups survived completely. Renal function--as indicated by plasma urea and cystatin c--was significantly worse in SHR-TR animals compared to all other groups. With plasma creatinine a similar trend was observed. All treatment options significantly decreased albuminuria. Renal glomerulosclerosis was decreased by monotherapy, whereas combination therapy failed to have a significant effect. Interstitial fibrosis was decreased to a similar extent by all treatment options.. ACEI/ARB combination treatment failed to render significant additional benefits on renal outcome in hypertensive rats when compared to monotherapy. Instead our data indicate that dual RAAS blockade might have an adverse effect on kidney function and histology when compared to monotherapy in salt-loaded SHR-SP.

Topics: Animals; Antihypertensive Agents; Benzimidazoles; Benzoates; Blood Pressure; Body Weight; Drug Therapy, Combination; Kidney Function Tests; Organ Size; Ramipril; Rats; Rats, Inbred SHR; Survival Rate; Telmisartan

Glucose-fed rat is a model of insulin resistance that displays sensory polyneuropathy and hypertension. This study aimed at comparing the beneficial effects of N-acetyl-L-cysteine (NAC, antioxidant) and ramipril (angiotensin-1 converting enzyme inhibitor) on tactile and cold allodynia induced by chronic glucose feeding. Impact of these treatments was also assessed on hypertension, plasma glucose and insulin concentrations, insulin resistance and kinin B(1) receptor expression. Male Wistar rats (50-75 g) were given 10% d-glucose in their drinking water for 11 weeks or tap water (controls). Glucose-fed rats were treated either with NAC (1 g/kg/day, gavage), ramipril (1 mg/kg/day in drinking water) or no drug during the last 5 weeks. Glucose feeding for 6 weeks induced a significant increase in systolic blood pressure and hyperglycaemia which was accompanied by tactile and cold allodynia. At 11 weeks, plasma insulin, insulin resistance (HOMA index), kinin B(1) receptor mRNA in spinal cord and renal cortex and B(1) receptor binding sites in spinal cord were enhanced in glucose-fed rats. NAC and ramipril caused a progressive to complete inhibition of tactile and cold allodynia from 6 to 11 weeks. High systolic blood pressure, hyperinsulinemia, insulin resistance and kinin B(1) receptor expression were also normalized or attenuated in glucose-fed rats by either treatment. Results suggest that chronic treatment with an antioxidant or an ACE inhibitor provides similar beneficial effects on sensory polyneuropathy, hypertension and insulin resistance in glucose-fed rats. Both therapies were associated with a reduction of the expression of the pro-nociceptive kinin B(1) receptor.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Antioxidants; Blood Glucose; Blood Pressure; Body Weight; Cystine; Diabetes Complications; Disease Models, Animal; Down-Regulation; Drinking; Eating; Glucose; Hyperalgesia; Hypertension; Insulin; Insulin Resistance; Kidney Cortex; Male; Pain Measurement; Ramipril; Rats; Rats, Wistar; Receptor, Bradykinin B1; RNA, Messenger; Sensation; Spinal Cord; Time Factors

The RhoA-Rho kinase (ROCK) signaling pathway has an important role in cardiovascular diseases. However, the effect of Rho kinase inhibition on pressure overload-induced cardiac hypertrophy (POH) and associated diastolic dysfunction has not been evaluated. This study examined the effect of a selective ROCK inhibitor (GSK-576371) in a POH model, induced by suprarenal abdominal aortic constriction. POH rats were divided into the following four groups: 1 (GSK 1, n = 9) or 3 (GSK 3, n = 10) mg/kg bid GSK-576371, 1 mg.kg(-1).day(-1) ramipril (n = 10) or vehicle (n = 11) treatment for 4 wk. Sham animals (n = 11) underwent surgery without banding. Echocardiograms were performed before surgery and posttreatment, and hemodynamic data were obtained at completion of the study. Echocardiography showed an increase in relative wall thickness of the left ventricle (LV) following POH + vehicle treatment compared with sham animals. This was attenuated by both doses of GSK-576371 and ramipril. Vehicle treatment demonstrated abnormal diastolic parameters, including mitral valve (MV) inflow E wave deceleration time, isovolumic relaxation time, and MV annular velocity, which were dose dependently restored toward sham values by GSK-576371. LV end diastolic pressure was increased following POH + vehicle treatment compared with sham (6.9 +/- 0.7 vs. 3.2 +/- 0.7 mmHg, P = 0.008) and was reduced with GSK 3 and ramipril treatment (1.7 +/- 0.7, P < 0.01 and 2.9 +/- 0.6 mmHg, P < 0.01, respectively). Collagen I deposition in the LV was increased following POH + vehicle treatment (32.2%; P < 0.01) compared with sham animals and was significantly attenuated with GSK 1 (21.7%; P < 0.05), GSK 3 (23.8%; P < 0.01), and ramipril (35.5%; P < 0.01) treatment. These results suggest that ROCK inhibition improves LV geometry and reduces collagen deposition accompanied by improved diastolic function in POH.

Topics: Animals; Animals, Newborn; Antihypertensive Agents; Aorta, Abdominal; Body Weight; Cardiomegaly; Cell Proliferation; Cell Size; Cells, Cultured; Collagen; Diastole; Disease Models, Animal; Dose-Response Relationship, Drug; Echocardiography; Fibroblasts; Fibrosis; Hemodynamics; Hypertension; Immunohistochemistry; Ligation; Male; Myocardium; Myocytes, Cardiac; Polymerase Chain Reaction; Protein Kinase Inhibitors; Ramipril; Rats; Rats, Sprague-Dawley; rho-Associated Kinases; Ventricular Function, Left

Atrial natriuretic peptide (ANP) exerts beneficial effects on the cardiovascular system in part by exerting antioxidant activity. Given that oxidant stress is a key cause of endothelial dysfunction in diabetes, we investigated whether ANP improves endothelial function in rats with diabetes. Rats were injected with streptozotocin (55 mg/kg iv) to induce type 1 diabetes or the citrate vehicle as controls (n=12). After 4 weeks the diabetic rats were treated with ANP (10 pmol/kg/min sc, n=12) or the antioxidant tempol (1.5 mmol/kg/day sc, n=11), both by osmotic minipump, ramipril (1 mg/kg per day in the drinking water) or remained untreated (n=11). After a further 4 weeks, anaesthetised rats were killed by exsanguination and the thoracic aortae collected for examination of vascular activity and measurement of superoxide generation. Diabetic rats showed elevated plasma glucose concentration (45+/-3 mM) compared to controls (10+/-1 mM) and this was not affected by ANP (43+/-3 mM), ramipril (41+/-2 mM) or tempol (43+/-2 mM). Endothelium-dependent relaxation ex vivo in response to acetylcholine was impaired in diabetic rats (Rmax=66+/-4%) compared to control rats (Rmax=94+/-1%) but treatment with ANP (Rmax=80+/-4%), ramipril (Rmax=88+/-2%) or tempol (Rmax=81+/-5%) significantly improved those responses. Relaxant responses to the endothelium-independent vasodilator sodium nitroprusside were enhanced by treatment of diabetic rats with ANP or ramipril and their combination; but not by tempol. Superoxide generation was significantly elevated in aorta from untreated diabetic rats (649+/-146% of control). In diabetic rats, superoxide generation was significantly attenuated by ANP (to 229+/-78%) or tempol (to 186+/-64%). This study demonstrates that ANP improves vascular oxidant stress in concert with endothelial function, independent of any effect on plasma glucose levels. These studies may lead to new therapies, based on natriuretic peptide and/or antioxidant approaches, for ameliorating the vascular complications of diabetes.

Topics: Aging; Angiotensin-Converting Enzyme Inhibitors; Animals; Antioxidants; Aorta, Thoracic; Atrial Natriuretic Factor; Blood Glucose; Blood Pressure; Blotting, Western; Body Weight; Cyclic N-Oxides; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetic Angiopathies; Endothelium, Vascular; Male; Muscle Relaxation; NADPH Oxidases; Nitric Oxide Synthase Type III; Nitroprusside; Ramipril; Rats; Rats, Sprague-Dawley; Spin Labels; Superoxides; Vasodilator Agents

To observe the effect of angiotensin II (Ang II) on expression of gap junction channel protein connexin 43 (Cx43) in the proliferation process of vascular smooth muscle cells (VSMCs) during the early stage of arteriosclerosis.. Thirty-two adult male rabbits were randomly divided into 4 groups. Rabbits in Group A were fed common diet while others in Groups B, C, and D were fed high-cholesterol diet. Losartan (10 mg/(kg.d)) and ramipril (0.5 mg/(kg.d)) were added in the diet of Groups C and D, respectively. The animals were sacrificed after 8 weeks and abdominal aortas were removed and dissected. The expression of Cx43 was assayed using RT-PCR and Western Blotting analysis.. Cx43 was increased markedly in both protein and mRNA level in Groups B, C, and D fed high-cholesterol diet compared with that in control group (P<0.01). Cx43 level in losartan or ramipril treated groups was higher than that in control group (P<0.01, P<0.05), but lower than that in high-cholesterol diet groups (P<0.05, P<0.01).. Cx43 level was upregulated in VSMCs during early atherosclerosis. Losartan and ramipril can inhibit the expression of Cx43.

Topics: Angiotensin II; Animals; Arteriosclerosis; Body Weight; Cholesterol; Connexin 43; Losartan; Male; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Rabbits; Ramipril; RNA, Messenger

The effects of the sodium-hydrogen (Na/H) exchange inhibitor cariporide (HOE642), on insulin sensitivity and vascular function were studied in the JCR:LA-cp rat and the db/db mouse. In the insulin-resistant rat, cariporide reduced fasting insulin levels (42%, P < 0.02) and insulin response in a meal tolerance test (50%, P < 0.01), indicating increased insulin sensitivity. The ACE inhibitor, ramipril, used as a reference agent, reduced the insulin response to the meal, but not fasting levels. The EC50 for acetylcholine-mediated relaxation of phenylephrine-precontracted aortic rings was significantly lower in cariporide-treated rats (P < 0.002), but not in ramipril-treated rats. Flow response of the coronary circulation to bradykinin was significantly greater in both cariporide- and ramipril-treated rats, (3-fold decrease in the EC50, P < 0.05). Cariporide-treated hearts were smaller, slower beating, with greater developed LVP. In the obese db/db mouse, chronic treatment with cariporide obviated vascular hypercontractility and improved endothelial function. Thus, cariporide had beneficial effects on the abnormal insulin metabolism and associated vascular dysfunction in the JCR:LA-cp insulin-resistant rat, which develops advanced cardiovascular disease and ischemic myocardial lesions. It also improved vascular function in a similar mouse model of insulin resistance. These effects were markedly greater than those of ramipril.

Topics: Acetylcholine; Animals; Aorta; Body Weight; Coronary Circulation; Eating; Guanidines; Heart; Insulin; Insulin Resistance; Male; Mice; Mice, Inbred C57BL; Nitroprusside; Obesity; Ramipril; Rats; Receptors, Cell Surface; Receptors, Leptin; Sodium-Hydrogen Exchangers; Sulfones; Vasoconstriction

We evaluated whether ramipril, one of long-acting ACEIs, has a direct effect on pancreas islets in animal model of type 2 diabetes. OLETF rats were treated with ramipril for 24 weeks. We assessed the body weight, glucose tolerance, and the amount of islet fibrosis. RT-PCR and Western blot analysis of transforming growth factor-beta with its downstream signals were performed from the pancreas. Ramipril treatment remarkably reduced weight gain and the area under the curve of glucose. Islet fibrosis and the expression of TGF-beta with its downstream signal molecules were significantly reduced in the pancreas of ramipril-treated group than in control and paired-feeding group. These beneficial effects of ramipril might be related to the downregulation of TGF-beta and its downstream signals in OLETF rats. To our knowledge, this is the first report suggesting the potential effect of ramipril on the prevention of islet destruction by fibrosis in the animal model of type 2 diabetes mellitus.

Topics: Actins; Angiotensin-Converting Enzyme Inhibitors; Animals; Blotting, Western; Body Weight; Diabetes Mellitus, Type 2; Fibrosis; Glucose Tolerance Test; Insulin Resistance; Islets of Langerhans; Male; Ramipril; Rats; Rats, Inbred OLETF; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Transforming Growth Factor beta

The insulin-resistant, hyperinsulinemic, normoglycemic, and obese JCR:LA-cp rat was used to study the effects of ramipril (an ACE inhibitor) and AVE7688 (a dual inhibitor of ACE and neutral endopeptidases) on insulin sensitivity and vascular function. Both compounds reduced the surge of plasma insulin in a meal tolerance test by approximately 50%. Ramipril had no effect on acetylcholine-induced relaxation but increased the sensitivity to sodium nitroprus-side at low concentrations. AVE7688 significantly reduced the EC50 for acetylcholine to relax phenylephrine-contracted aortic rings. None of the compounds affected the baseline coronary flow and reactive hyperemia. Coronary flow response to bradykinin in AVE7688- and ramipril-treated rat hearts showed a significantly lower EC50 than in control rats. Maximum flow rate was not different between groups. In summary, both ramipril and AVE7688 had significant hypoinsulinemic and insulin-sensitizing effects. Whereas ramipril had limited vascular effects, AVE7688 had more marked beneficial vascular effects, probably of endothelial origin and possibly related to lowered insulin levels.

Topics: Acetylcholine; Administration, Oral; Angiotensin-Converting Enzyme Inhibitors; Animals; Animals, Genetically Modified; Aorta, Thoracic; Blood Glucose; Body Weight; Bradykinin; Diet; Disease Models, Animal; Eating; Endothelium, Vascular; Fasting; Heart; Heart Rate; Heterocyclic Compounds, 3-Ring; Insulin; Insulin Resistance; Male; Muscle, Smooth, Vascular; Neprilysin; NG-Nitroarginine Methyl Ester; Nitroprusside; Obesity; Organ Size; Phenylephrine; Ramipril; Rats; Vasoconstriction; Vasodilation

Topics: Aged; Aged, 80 and over; Amlodipine; Antihypertensive Agents; Basal Ganglia Cerebrovascular Disease; Blood Pressure Monitoring, Ambulatory; Blood Urea Nitrogen; Body Weight; Cerebral Infarction; Circadian Rhythm; Dose-Response Relationship, Drug; Drug Therapy, Combination; Follow-Up Studies; Glycated Hemoglobin; Humans; Hypertension; Internal Capsule; Male; Oxazoles; Prognosis; Ramipril; Rilmenidine; Sympathetic Nervous System

Cardiovascular disease is the major cause of death in Western nations, although improved possibilities regarding diagnosis and therapy now exist. Endothelial dysfunction is triggered by cardiovascular risk factors such as hypercholesterolaemia, hypertension, adiposity and smoking, contributing to the common endpoint of atherosclerosis. This study examined the pharmacological effects of angiotensin-converting enzyme (ACE) and combined ACE-neutral endopeptidase (NEP) (vasopeptidase) inhibitors on endothelial dysfunction in the model of hyperlipidaemic rabbits. The focus of the study was to assess endothelial function after treatment with the ACE-NEP inhibitor AVE 7688 (30 mg/kg/day) in comparison to the ACE inhibitor (ACE-I) ramipril (1 mg/kg/day). Different parameters, such as endothelial function, blood pressure (BP), expansion of plaques, endothelial nitric oxide (NO) and superoxide (O2-) release and plasma levels of various lipidaemic parameters were analysed. Control groups consisted of one group fed only with normal diet, one group fed only with atherogenic diet and the direct control group fed with varied diets (six weeks atherogenic diet followed by 12 weeks normal diet). Since for the treatment of atherosclerosis, a change in feeding is absolutely necessary, in the present study, at the start of the treatments with AVE 7688 and ramipril, the rabbits food was changed to a normal diet. At the end of the study, mean arterial blood pressure (MAP) was measured in the anaesthetised animals. The values in standard, atherogenic and varied diet-fed rabbits were around 73 2 mmHg. Angiotensin I (Ang I) given intravenous (i.v.) induced a strong increase in MAP of about 20%. In both the treated groups Ang I-induced BP increase was inhibited. In contrast, i.v. bradykinin led to a strong reduction in MAP in both the treated groups of around 50%. Six weeks feeding with an atherogenic diet in the rabbits induced an enduring endothelial dysfunction despite the food subsequently being changed to a normal chow. All measured parameters indicated a significant favourable effect on endothelial dysfunction as a result of the two treatment regimens. Endothelial function measured in the organ chamber showed somewhat greater improvement in the ACE-NEP treated group than in the ACE-I treated group. The treatment with ramipril, as well as with AVE 7688, restored endothelial function by increasing the ratio of NO to O2- concentration and bioavailability of NO. In this study, a

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta; Arteriosclerosis; Blood Pressure; Body Weight; Diet, Atherogenic; Disease Models, Animal; Drug Therapy, Combination; Endothelium, Vascular; Heterocyclic Compounds, 3-Ring; Hypercholesterolemia; Male; Neprilysin; Prodrugs; Rabbits; Ramipril

To investigate the effects of the dual angiotensin-converting enzyme (ACE) + neutral endopeptidase (NEP) inhibitor, MDL-100,240 (MDL), on hypertension and cardiovascular damage in male heterozygous transgenic Ren2 rats.. Blood-pressure-matched 5-week-old transgenic rats were allocated to receive a placebo, MDL (40 mg/kg body weight) or ramipril (5 mg/kg body weight) for 8 weeks. During the last 4 weeks, the bradykinin B2 receptor antagonist, icatibant (0.5 mg/kg body weight), was also administered subcutaneously via osmotic minipumps to 50% of the transgenic rats receiving MDL or ramipril. We measured blood pressure, heart weight, structural changes in the aorta and small resistance mesenteric arteries, and the plasma concentrations of adrenomedullin, aldosterone, atrial natriuretic peptide and cGMP. To verify if MDL could regress long-standing hypertension and full-blown cardiovascular damage, 3-month-old transgenic rats received MDL subcutaneously (3 and 10 mg/kg body weight, osmotic minipumps) for 4 weeks.. Compared with placebo, MDL decreased blood pressure (P < 0.001) and prevented left ventricular hypertrophy (P < 0.001), being as effective as ramipril. Hypertrophy and dilatation of the aorta and hypertrophy of the resistance arterioles were all prevented by MDL. Plasma aldosterone was decreased by MDL (P < 0.001), but not by ramipril. Icatibant blunted the decrease in blood pressure (P < 0.001), decreased cGMP concentrations and blunted the decrease in cross-sectional area of the resistance arteries in MDL-treated, but not in ramipril-treated, transgenic rats. In 3-month-old transgenic rats, MDL normalized blood pressure, regressed left ventricular hypertrophy and decreased adrenomedullin concentrations.. The dual ACE+NEP inhibitor MDL prevented and regressed severe hypertension and cardiovascular damage, even in this model of severe angiotensin II-dependent hypertension with pronounced cardiovascular damage. Enhancement of the effects of bradykinin has a role in such favourable outcomes.

Topics: Adrenomedullin; Aldosterone; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Animals, Genetically Modified; Antihypertensive Agents; Benzazepines; Biomarkers; Blood Pressure; Body Weight; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Therapy, Combination; Enzyme Inhibitors; Heart; Hypertension; Male; Models, Cardiovascular; Neprilysin; Organ Size; Peptides; Pyridines; Ramipril; Rats; Rats, Sprague-Dawley; Receptor, Bradykinin B2; Receptors, Bradykinin; Severity of Illness Index; Systole; Treatment Outcome; Vasoconstrictor Agents

It is well established that angiotensin-converting enzyme (ACE) inhibitors (ACEI) reduce blood pressure (BP) and hypertrophy of the left ventricle and vessels. The aim of our study was to compare chemically different ACEIs regarding their ability to modulate left ventricular and media hypertrophy, ACE activity and plasma endothelin-1 concentrations in spontaneously hypertensive rats (SHRs).. After establishing equi-effective dose regimes, SHRs were treated (3 months) with captopril, enalapril, fosinopril or ramipril (2 x 25, 10, 20 or 1 mg/kg per day or corresponding 1% doses for studying blood pressure-independent effects).. Systolic blood pressure was reduced in SHRs receiving high doses of captopril, enalapril, fosinopril or ramipril (-61, -54, -35 and -47 mmHg), whereas low doses were ineffective. Left ventricular weight was decreased in animals treated with high doses (captopril/enalapril/fosinopril/ramipril: -17/-19/-17/-19%), but not low doses of agents. Media thickness of thoracal aorta was reduced by administering high doses (captopril/enalapril/fosinopril/ramipril: -31/-32/-27/-26%) and low doses (-16/-22/-22/-19%) of agents. ACE activity was reduced in heart, aorta and kidney of rats treated with high and low doses of all ACE inhibitors, whereby high doses showed more pronounced effects. Plasma endothelin-1 concentrations were not altered. A blood-pressure-ineffective treatment with an AT -antagonist revealed similar effects on cardiovascular hypertrophy.. ACEIs reduce cardiovascular hypertrophy uniformly via an AT -receptor- mediated mechanism, reinforcing the opinion that ACEI effects are indeed class effects. The significance of local renin-angiotensin systems was confirmed by antihypertrophic effects in the aorta that were apparent in the absence of any blood pressure reduction.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta, Thoracic; Blood Pressure; Body Weight; Captopril; Circadian Rhythm; Dose-Response Relationship, Drug; Enalapril; Endothelin-1; Fosinopril; Hypertrophy, Left Ventricular; Male; Peptidyl-Dipeptidase A; Ramipril; Rats; Rats, Inbred SHR

We investigated the effects of MDL-100,240 in a transgenic rat model (TGRen2) of hypertension with severe cardiovascular damage (CVD) due to enhanced tissue synthesis of angiotensin II (Ang II). Male heterozygous TGRen2 rats (5 weeks old) were allocated to receive MDL-100,240, ramipril (RAM) or placebo (PLAC) for 4 weeks, during which blood pressure (BP) was measured. We then evaluated: 1) left ventricle (LV) and right ventricle (RV), brain, kidney and adrenals weight; 2) structural changes in the aorta and the mesenteric arterioles wall; 3) tension responses of segments of the aorta to phenylephrine, KCl, and endothelin-1; and 4) creatinine, aldosterone, atrial natriuretic peptide (ANP), and cyclic GMP (cGMP) plasma levels. Compared to PLAC, both MDL-100,240 and RAM significantly (P < .001) lowered BP (after 4 weeks: 255 +/- 15 mm Hg PLAC, v 174 +/- 6 MDL-100,240, v 166 +/- 5 RAM). They hindered LV hypertrophy (3.73 +/- 0.25 mg/g body weight (PLAC) v 2.71 +/- 0.22 (MDL-100,240) P < .001; v 2.36 +/- 0.2 (RAM), P < .001). MDL-100,240 also prevented aortic dilatation and hypertrophy of the mesenteric arterioles (media thickness, 25.3 +/- 0.5 microm PLAC, v 21.1 +/- 0.9 MDL-100,240, P < .007; v 20.2 +/- 1.5 RAM, P = .033) and lowered the tension responses to phenylephrine (P < .01), KCl (P < .01), and endothelin-1 (P < .001). Plasma aldosterone (710 +/- 153 pmol/L PLAC, v 237 +/- 61 MDL-100,240, v 180 +/- 22 RAM) and creatinine levels (0.69 +/- 0.33 mg/dL PLAC, v 0.41 +/- 0.02 MDL-100,240, v 0.41 +/- 0.04 RAM) were also decreased (P < or = .001). Compared to PLAC, plasma ANP levels were 11% and 2.4% higher in MDL-100,240 and RAM, respectively (both P = not significant); cGMP levels were unaffected. Thus, severe hypertension and related CVD were regressed by MDL-100,240, which resulted to be as effective as a full dosage of ramipril in TGRen2.

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Animals, Genetically Modified; Aorta; Benzazepines; Blood Pressure; Body Weight; Cardiovascular Diseases; Hypertension; In Vitro Techniques; Male; Neprilysin; Organ Size; Pyridines; Ramipril; Rats; Vasoconstriction

Angiotensin II (Ang II) infusion in rats augments vascular injury in balloon-injured carotid arteries and induces marked vascular and tubulointerstitial injury in kidneys. We examined how the AT1 receptor is modulated and whether blockade of the receptor with losartan could prevent the phenotypic and cellular changes. We also examined the role of the local renin-angiotensin system (RAS) by examining the expression of angiotensin-converting enzyme (ACE) and the effect of treatment with the ACE inhibitor, ramipril. Ang II infusion resulted in systemic hypertension and accelerated intimal and medial thickening in balloon-injured carotid arteries. Renal injury was manifested by proteinuria, glomerular phenotypic changes (mesangial expression of alpha-actin and podocyte expression of desmin), and tubulointerstitial injury with the tubular upregulation of the macrophage-adhesive protein, osteopontin, the interstitial accumulation of macrophages and myofibroblasts, and the deposition of collagen types III and IV. Ang II infusion decreased AT1 receptor number in the renal interstitium but not in glomeruli. Losartan completely blocked the Ang II-mediated hypertension, proteinuria, and injury to both carotid and kidney. Ang II infusion was also associated with an increase in ACE protein in both the proximal tubular brush border as well as at interstitial sites of injury, but despite evidence for activation of the local RAS, treatment with ramipril was without effect. These studies demonstrate that the renal and vascular injury induced by Ang II infusion is mediated by the AT1 receptor despite downregulation of the receptor in the interstitium. In addition, although there is evidence for local RAS activation, the injury appears to be mediated solely by the exogenous Ang II.

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Blood Pressure; Body Weight; Carotid Artery Injuries; Catheterization; Kidney Diseases; Losartan; Male; Peptidyl-Dipeptidase A; Ramipril; Rats; Rats, Sprague-Dawley; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Angiotensin; Vasoconstrictor Agents

We previously reported that inhibition of angiotensin-converting enzyme (ACE) prevented the hypertension and left ventricular hypertrophy induced by deoxycorticosterone acetate-salt (DOCA-salt) in 129/SvEvTac mice, which have 2 renin genes (Ren-1 and Ren-2). In the present study, we induced hypertension by uninephrectomy and DOCA-salt in mice having only the Ren-1 gene (C57BL/6J) and investigated the effect of an ACE inhibitor (ramipril, 4 mg. kg(-)(1). d(-)(1)) and an angiotensin type 1 (AT(1)) receptor antagonist (L-158809, 4 mg. kg(-)(1). d(-)(1)) on the development of hypertension, cardiac hypertrophy, and renal injury. After 4 weeks of treatment, systolic blood pressure in DOCA-salt mice was significantly increased (128+/-2 mm Hg) compared with controls (109+/-2 mm Hg) (P:<0.001), while plasma renin concentration was decreased by 97% (P:<0.001). DOCA-salt also induced left ventricular and renal hypertrophy and renal damage as manifested by proteinuria. Collagen content in the left ventricle and kidney was significantly higher in DOCA-salt mice (P:<0.001). Urinary albumin (P:<0.05) and proliferating cell nucleic antigen-positive cells in the tubules and interstitium of the renal cortex (P:<0.001) were significantly increased in the DOCA-salt group. Neither the ACE inhibitor nor the AT(1) antagonist had any antihypertensive effect; however, they partially prevented cardiac hypertrophy and completely inhibited left ventricular collagen deposition. In the kidney, both the ACE inhibitor and AT(1) antagonist partially reduced the increase in collagen but had no effect on hypertrophy. They also significantly prevented the effect of DOCA-salt on urinary albumin and proliferating cell nucleic antigen expression in the kidney. Despite the lack of an antihypertensive effect, both ACE inhibitor and AT(1) antagonist prevented cardiac remodeling and renal damage. Our results indicate that ACE inhibitors and AT(1) antagonists exert beneficial effects on the heart and kidney in DOCA-salt hypertensive mice independently of their effects on blood pressure.

Topics: Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Body Weight; Collagen; Desoxycorticosterone; Hypertension; Hypertrophy, Left Ventricular; Imidazoles; Immunohistochemistry; Kidney Cortex; Kidney Tubules; Mice; Mice, Inbred C57BL; Mice, Knockout; Nephrectomy; Organ Size; Proliferating Cell Nuclear Antigen; Ramipril; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Renin; Sodium Chloride; Tetrazoles

We aimed to examine the time course for the diabetes-related changes in renal lysosomal processing and to determine whether these changes can be prevented by aminoguanidine or ramipril treatment.. The percentage desulphation of intravenously injected tritium labelled dextran sulphate ([3H]DSO4) in the urine, as determined by ion-exchange chromatography, was used as a marker of lysosomal sulphatase activity. Sulphatase activity was determined 1, 2, 3 and 4 weeks after the onset of diabetes in rats as well as in rats treated with either aminoguanidine or ramipril for twelve weeks.. The amount of totally desulphated [3H]DSO4 in urine collected from control rats was 65.6 +/- 0.8%. This was significantly reduced in diabetic rats two (57.4 +/- 1.4% desulphated), three (56.8 +/- 1.3 % desulphated) and four (52.9 +/- 2.2% desulphated) weeks after the onset of diabetes. The significant decrease in the amount of totally desulphated [3H]DSO4 in the urine also found at 12 weeks after the onset of diabetes was not affected by drug treatment. There was no significant difference in the amount of partially desulphated [3H]DSO4 in the urine between all the study groups. However, the increase in totally sulphated [3H]DSO4 in the urine collected from diabetic rats (8.7 +/- 1.7 % sulphated) compared with that of control rats (2.2 +/- 0.5% sulphated) was normalised by treatment with both aminoguanidine (4.8 +/- 1.6% sulphated) or ramipril (4.5 +/- 0.8% sulphated).. These results raise the possibility that the diabetes-induced changes in renal lysosomal processing may be one of the initial events in the development of diabetic nephropathy. Aminoguanidine and ramipril, known for their different mechanism of action, seem to prevent diabetes-induced changes in lysosomal processing either through their effects on enzyme activity within the lysosome or through their effects on the trafficking of molecules to and from the lysosome.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Glucose; Blood Pressure; Body Weight; Chromatography, Ion Exchange; Dextran Sulfate; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Enzyme Inhibitors; Glomerular Filtration Rate; Guanidines; Kidney; Kinetics; Lysosomes; Male; Nitric Oxide Synthase; Ramipril; Rats; Rats, Sprague-Dawley; Sulfatases; Sulfates; Tritium

Angiotensin-converting enzyme inhibitors and alpha1-adrenoceptor antagonists improve glucose disposal in diabetes mellitus. We compared the effect of the antihypertensive hybrid drug urapidil [alpha1-adrenoceptor antagonist serotonin 1A (5-hydroxytryptamine 1A, 5-HT1A) receptor agonist] on hyperglycemia in streptozotocin diabetic rats with the angiotensin-converting enzyme inhibitor ramipril. 5-HT1A receptor agonists induce hyperglycemia. This could be an important disadvantage during treatment of diabetes mellitus with urapidil. Diabetes was induced by streptozotocin (70 mg/kg i.p.). Treatment for 7 days (ramipril 10 mg/kg p.o.; urapidil 20 mg/kg p.o.) significantly decreased mean blood glucose values (urapidil: 15.7+/-0.9 mmol/l, P=0.007; ramipril: 15.0+/-0.8 mmol/l, P=0.038 vs. diabetic control group: 18.7+/-1.0 mmol/l). Both drugs reduced significantly blood pressure, urinary glucose, water consumption, and food requirement. Serotonin concentration in the brain (medulla oblongata, pituitary) was not affected. A normalization comparable with healthy control rats was observed only in a diabetic control group with insulin therapy. In conclusion, our results demonstrate that the antihypertensive drug urapidil has no detrimental effect on hyperglycemia compared with the angiotensin-converting enzyme inhibitor ramipril in experimental diabetes mellitus despite its 5-HT1A receptor agonistic properties.

Topics: Adrenergic alpha-Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Glucose; Blood Pressure; Body Weight; Diabetes Mellitus, Experimental; Drinking; Eating; Glycosuria; Hyperglycemia; Insulin; Male; Medulla Oblongata; Piperazines; Pituitary Gland; Ramipril; Rats; Rats, Inbred WKY; Serotonin; Serotonin Receptor Agonists

Topics: Angiotensin-Converting Enzyme Inhibitors; Body Weight; Diabetes Mellitus, Type 2; Humans; Ramipril

We investigated the role of kinin and nitric oxide (NO) in the modulation of cardiac O(2)consumption in Syrian hamsters with overt heart failure (HF) and age-matched normal hamsters. Using echocardiography, the hamsters with heart failure had reduced ejection fraction [31(+/-8) v 76(+/-5)%] and LV dilation [4.9(+/-0. 2) v 5.7(+/-0.3) mm, both P<0.05 from normal]. O(2)consumption in the left ventricular free wall was measured using a Clark-type O(2)electrode in an air-tight chamber, containing Krebs solution buffered with Hepes (37 degrees C, pH 7.4). Concentration response curves to bradykinin (BK), ramiprilat (RAM), amlodipine (AMLO) and the NO donor, S -nitroso- N -acetyl-penicillamine (SNAP) were performed. Basal myocardial O(2)consumption was lower in the HF group compared to normal [316(+/-21) v 404(+/-36) nmol O(2)/min/g, respectively, P<0.05]. In the hearts from normal hamsters BK (10(-4)mol/l), RAM (10(-4)mol/l), and AMLO (10(-5)mol/l) all significantly reduced myocardial O(2)consumption by 42(+/-6)%, 29(+/-7)% and 27(+/-5)% respectively. This reduction was attenuated in the presence of N -nitro- l -arginine methyl ester (l -NAME) [BK: 3.3(+/-1.5)%, RAM: 3.3(+/-1.2)%, AMLO: 2.3(+/-1.2)%, P<0.05]. Interestingly in the hearts from HF group, BK, RAM and AMLO caused a significantly smaller reduction in myocardial O(2)consumption [10(+/-2)%, 2.5(+/-1.3)%, 6.3(+/-2.3)%, P<0.05]. In contrast, the NO donor SNAP reduced myocardial O(2)consumption in both groups and all those responses were not affected by l -NAME. These data indicate that endogenous NO production through the kinin-dependent mechanism is impaired at end-stage heart failure. The loss of kinin and NO control of mitochondrial respiration may contribute to the pathogenesis of heart failure.

Topics: Amlodipine; Angiotensin-Converting Enzyme Inhibitors; Animals; Body Weight; Bradykinin; Cardiomyopathies; Cricetinae; Dose-Response Relationship, Drug; Echocardiography; Enzyme Inhibitors; Kinins; Male; Mesocricetus; Muscles; Myocardium; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Donors; Organ Size; Oxygen; Oxygen Consumption; Penicillamine; Ramipril; Vasodilator Agents

Spontaneously hypertensive rats (SHR) begin to die from cardiovascular complications at approximately 15 months of age. We tested whether chronic ACE-inhibitor treatment would extend the lifespan of such old animals. We also studied cardiac hypertrophy and function, endothelial function and expression, and activity of NO synthase (eNOS). One hundred 15-month-old SHR were randomized into 3 groups, control (n=10), placebo-treated (n=45), and ramipril-treated with an antihypertensive dose of 1 mg. kg(-1). d(-1) in drinking water (n=45). Ex vivo experiments were performed after 15 months (control) and 21 months, when approximately 80% of the placebo group had died. Late treatment with ramipril significantly extended lifespan of the animals from 21 to 30 months. Fully established cardiac hypertrophy, observed in placebo-treated animals and in controls, was significantly reversed by ramipril treatment. In isolated working hearts, a significantly improved function associated with increased cardiac eNOS expression was seen versus placebo and control hearts. Endothelial dysfunction in isolated aortic rings from control and placebo-treated SHR was significantly improved by ACE inhibition and associated with enhanced NO release. Late treatment of SHR with the ACE inhibitor ramipril extended lifespan from 21 to 30 months, which is comparable to the lifespan of untreated normotensive Wistar-Kyoto rats. This lifespan extension, probably due to blood pressure reduction, correlated with increased eNOS expression and activity followed by a regression of left ventricular hypertrophy and cardiac and vascular dysfunction.

Topics: Age Factors; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Aorta, Thoracic; Blood Pressure; Blotting, Western; Body Weight; Cardiomegaly; Data Interpretation, Statistical; Endothelium, Vascular; Heart; Heart Ventricles; Hypertension; In Vitro Techniques; Luminescent Measurements; Male; Myocardium; Nitric Oxide; Nitric Oxide Synthase; Placebos; Ramipril; Random Allocation; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Superoxides; Time Factors

The purpose of this study was to assess the role of transforming growth factor (TGF)-beta1 in the development of diabetes-associated mesenteric vascular hypertrophy and in the antitrophic effect of angiotensin converting enzyme inhibitors.. Streptozotocin-induced diabetic and control Sprague-Dawley rats were randomly allocated to treatment with the angiotensin converting enzyme inhibitor ramipril or to no treatment and were killed 1 or 3 weeks after the streptozotocin injection. Blood was collected and mesenteric vessels removed. Mesenteric vascular weight was measured and TGF-beta1 and alpha1 (type IV) collagen messenger (m)RNA levels were analysed by Northern analysis. Immunohistochemical analyses for TGF-beta1 and type IV collagen were also performed.. The diabetic rats had increased mesenteric vessel weight at 3 weeks but not at 1 week and a concomitant rise in mesenteric TGF-beta1 and in alpha1 (type IV) collagen mRNA levels. Ramipril treatment attenuated mesenteric vessel hypertrophy and prevented the increase in TGF-beta1 and alpha1 (type IV) collagen mRNA levels after 3 weeks of diabetes. The immunohistochemical analysis revealed that diabetes was associated with increased TGF-beta1 and type IV collagen protein and extracellular matrix accumulation in mesenteric vessels, and this increase was reduced by ramipril treatment.. These results support the concept that TGF-beta is involved in the changes associated with diabetic vascular disease, and suggest a mechanism by which angiotensin converting enzyme inhibitors exert their antitrophic effects.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Glucose; Blood Pressure; Blotting, Northern; Body Weight; Collagen; Diabetes Mellitus, Experimental; Diabetic Angiopathies; Gene Expression; Immunohistochemistry; Male; Ramipril; Rats; Rats, Sprague-Dawley; RNA, Messenger; Transforming Growth Factor beta; Vascular Diseases

The kallikrein-kinin system (KKS) has been postulated to play a role in modulation of hemodynamic function in diabetes and to contribute to the hemodynamic effects of angiotensin-converting enzyme inhibition (CEI). To further explore the KKS and its interactions with the renin-angiotensin system (RAS), studies were conducted in nondiabetic control rats and in moderately hyperglycemic diabetic rats. In protocol 1, control and diabetic rats were studied before and after administration of one of two dissimilar B2 kinin receptor antagonists (BK2As), or vehicle. At a low dose (0.5 microg x kg-1 x min-1), the first generation antagonist D-Arg,[Hyp3,Thi5,8,D-Phe7]-bradykinin significantly reduced the glomerular filtration rate (GFR) and renal plasma flow rate in diabetic rats, despite variable effectiveness in blocking the hypotensive response to injected bradykinin. However, a similar hemodynamic effect occurred in nondiabetic rats, suggesting that the observed effect was not specific to diabetes. Higher doses (20 microg bolus, then 1 microg x kg-1 x min-1 infusion) did not affect hemodynamics in either group, perhaps because of partial agonist effect. The second BK2A tested was the newer compound, icatibant (Hoe 140; D-Arg,[Hyp3,Thi5,D-Tic7,Oic8]-bradykinin). Hoe 140 consistently blocked the vasodepressor action of injected bradykinin, but had no effect on systemic or renal hemodynamics in either control or diabetic rats. In protocol 2, control and diabetic rats were pretreated with the CEI ramipril for 1-2 weeks, after which renal function was studied before and after Hoe 140 (0.1 mg s.c. and i.v.) or vehicle. CEI lowered blood pressure in both groups. Hoe 140 did not affect renal function in control rats, but in diabetic rats pretreated with ramipril, it induced a modest but significant decline in GFR. Ramipril induced the predicted changes in the systemic and intrarenal RAS, while acute BK2A had no consistent effect on RAS parameters. These studies suggest that the endogenous KKS has only a minor role in modulation of renal hemodynamics in the euvolemic diabetic rat, in the absence of KKS stimulation by CEI. However, angiotensin-converting enzyme is also kininase II, which serves to increase endogenous kinin activity. The increased kinin activity resulting from CEI treatment may participate, to a modest degree, in hemodynamic regulation of the diabetic kidney.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Glucose; Body Weight; Bradykinin; Bradykinin Receptor Antagonists; Diabetes Mellitus, Experimental; Glomerular Filtration Rate; Hemodynamics; Hyperglycemia; Kallikreins; Kidney; Kinins; Male; Organ Size; Ramipril; Rats; Rats, Wistar; Receptor, Bradykinin B2; Renal Circulation; Renin-Angiotensin System

Angiotensin-converting enzyme inhibitors have been shown to potentiate relaxations to kinins in several arteries, but the effects of long-term therapy on the responses to bradykinin in normotensive and hypertensive animals remain largely unknown. Therefore, the effects of 12-week-long ramipril therapy (1 mg kg-1 day-1) on responses of mesenteric arterial rings in vitro were studied in spontaneously hypertensive rats and normotensive Wistar-Kyoto rats. Endothelium-dependent relaxations of noradrenaline-precontracted rings to acetylcholine were similar in normotensive rats and ramipril-treated hypertensive rats and more pronounced than in untreated hypertensive group. Higher concentrations of bradykinin (0.1-1 microM) induced slight contractions in noradrenaline-precontracted endothelium-intact rings of normotensive groups and untreated hypertensive group, whereas no response or a transient relaxation were observed in ramipril-treated hypertensive rats. Interestingly, in ramipril-treated hypertensive rats but not in the other groups, 20-min. pretreatment of arterial rings with ramiprilat unmasked or potentiated the relaxations to bradykinin, and these bradykinin-induced relaxations were effectively inhibited by the B2-kinin receptor antagonist Hoe-140. In conclusion, ramipril treatment clearly improved endothelium-dependent arterial relaxation to acetylcholine, and potentiated of even unmasked the dilatory response mediated via the endothelial B2-kinin receptor in spontaneously hypertensive rats. Since these enhancing effects on arterial relaxation in vitro could not be attributed to reduced breakdown of bradykinin, the present results suggest that long-term angiotensin-converting enzyme inhibition potentiated the actions of kinins at level of B2-kinin receptors.

Topics: Acetylcholine; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Blood Pressure; Body Weight; Bradykinin; Disease Models, Animal; Endothelium, Vascular; Heart; Hypertension; Male; Mesenteric Arteries; Muscle Relaxation; Muscle, Smooth, Vascular; Norepinephrine; Organ Size; Ramipril; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptors, Bradykinin; Serotonin

The present investigation was undertaken to study the effects of chronic oral ramipril (1 mg/kg) treatment in streptozotocin (STZ) induced diabetic rats. Single tail vein injection of STZ (45 mg/kg, i.v.) produced a diabetic state exhibiting all the cardinal symptoms such as loss of body weight, polydipsia, polyuria, glucosuria, polyphagia, hypoinsulinaemia and hyperglycaemia. The diabetic state was also found to be associated with bradycardia, hypothyroidism, cardiac depression and cardiomyopathy. Ramipril treatment prevented STZ-induced hypertension, bradycardia, hypothyroidism, hyperchosesterolaemia and partially the cardiomayopathy. Ramipril treatment could not, however prevent STZ-induced loss of body weight, polyuria, polydipsia, polyphagia, hyperglycaemia, hypoinsulinaemia, hypertriglyceridaemia and cardiac depression. Our data suggests that ramipril has a few beneficial effects in the STZ-treated diabetic rats.

Topics: Animals; Antihypertensive Agents; Blood Pressure; Body Weight; Diabetes Mellitus, Experimental; Female; Heart; Heart Rate; Hypertension; Polyuria; Ramipril; Rats; Rats, Wistar; Streptozocin

In hypertension with cardiac hypertrophy, the specific contributions to increased production of the cardiac natriuretic peptides (NP) atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) by load and the hypertrophic process are not known. In the present work we determine ANF and BNP synthesis and secretion in the aortic-banded rat treated with dosage schedules of the ACE inhibitor ramipril that result in the prevention or regression of both hypertension and hypertrophy (high dosage) or in the prevention or regression of hypertrophy alone with persistent hypertension (low dosage). Myosin heavy chain (MHC) isoform switch was studied as an indicator of ventricular cardiocyte hypertrophy as well as the levels of collagen III mRNA as a measure of changes in extracellular matrix.. Ramipril was administered for 6 weeks just after suprarenal aortic banding, or rats were banded for 6 weeks, after which ramipril was administered during the following 6 weeks. Banding caused an increase in blood pressure, left ventricular weight-to-body weight ratio, plasma and ventricular NP, ventricular NP mRNA, collagen III, and beta-MHC mRNA. Ramipril at 1 mg/kg normalized all these parameters while ramipril at 10 micrograms/kg normalized left ventricular weight-to-body weight ratio but not blood pressure. Plasma and ventricular NP content and mRNA levels were partially normalized by ramipril (10 micrograms/kg). Ramipril (10 micrograms/kg) prevented increased collagen III mRNA levels but did not affect beta-MHC mRNA levels.. (1) NP production and secretion in aortic-banded rats are independently related to increased blood pressure and hypertrophy. (2) A load-dependent component is more important than a load-independent component in regulating left ventricular NP production. (3) ANF production is more sensitive than BNP production to the load-independent component. (4) Low-dose ramipril treatment reverses hypertrophy and the increased collagen III expression but does not reverse the increased beta-MHC isoform expression, suggesting that these are independently regulated processes. (5) Aortic banding and ACE inhibition do not affect atrial NP production and content.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Aorta; Atrial Natriuretic Factor; Base Sequence; Body Weight; Constriction; Hemodynamics; Hypertension; Hypertrophy, Left Ventricular; Male; Molecular Sequence Data; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Organ Size; Ramipril; Rats; Rats, Sprague-Dawley; Renin

Abnormalities of the vasopressin system are found in genetic hypertension. This study compares the delayed effects of a brief period of vasopressin V1A receptor blockade and angiotensin-converting enzyme inhibition in young female and male spontaneously hypertensive rats (SHR) on the development of hypertension in adult life. In a separate study, the role of vasopressin in the maintenance of blood pressure in adult SHR was assessed. Young SHR received either the nonpeptide vasopressin V1A receptor antagonist OPC-21268, the angiotensin-converting enzyme inhibitor ramipril, or vehicle from 6 to 10 weeks of age. During the treatment period, OPC-21268 and ramipril reduced systolic blood pressure compared with control SHR (P < .001). Blood pressure in male SHR 7 weeks after treatment withdrawal was 178 +/- 1 mm Hg in ramipril-treated, 184 +/- 1 mm Hg in OPC-21268-treated, and 200 +/- 2 mm Hg in control SHR (P < .001). Similar results were seen in female SHR, although both OPC-21268 and ramipril were less effective antihypertensive agents in female compared with male SHR. The sustained attenuation in blood pressure was not associated with significant cardiovascular structural changes (left ventricular-to-body weight ratio, renal weight-to-body weight ratio, mesenteric resistance artery media-to-lumen ratio). Results of vasopressin V1A receptor binding kinetics and plasma renin or aldosterone concentrations did not suggest a lasting effect of OPC-21268 on the vasopressin system or of ramipril on the renin-angiotensin system following treatment withdrawal.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aging; Angiotensin-Converting Enzyme Inhibitors; Animals; Antidiuretic Hormone Receptor Antagonists; Blood Pressure; Body Weight; Female; Hypertension; Male; Piperidines; Quinolones; Ramipril; Rats; Rats, Inbred SHR

Brief angiotensin-converting enzyme (ACE) inhibition in young spontaneously hypertensive rats (SHR) causes a persistent reduction in blood pressure. Bradykinin accumulation may contribute to these long-term effects, and to test this hypothesis we studied the consequences of bradykinin B2 receptor antagonism during ACE inhibitor treatment in young SHR. Male SHR were treated from 6 to 10 weeks of age with water, ramipril (1 mg/kg per day), Hoe 140 (0.5 mg/kg per day), or both ramipril and Hoe 140. Systolic blood pressure and body weight were measured each week from 6 to 20 weeks of age. During treatment, Hoe 140 treatment resulted in lower blood pressures than in controls. Rampiril caused a larger fall in blood pressure over the same period. The ramipril plus Hoe 140 group had the lowest blood pressures of any group during treatment. After treatment, the blood pressure of Hoe 140-treated SHR was similar to that of untreated SHR. After ramipril, blood pressure rose but plateaued significantly below values in controls. In contrast, withdrawal of combined ramipril and Hoe 140 treatment caused a rapid rise of systolic blood pressure to levels significantly higher than in ramipril-treated SHR but less than in controls. The antihypertensive effects of Hoe 140 during the development of genetic hypertension may represent a direct effect of the drug or some alteration in the normal relation between bradykinin and blood pressure. The antagonism by Hoe 140 of the long-term blood pressure reduction after ramipril withdrawal indicates that the persistent effects of ACE inhibitors may in part be due to the accumulation of bradykinin during a critical stage of development.

Topics: Aging; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Body Weight; Bradykinin; Hypertension; Male; Ramipril; Rats; Rats, Inbred SHR; Time Factors

The renin-angiotensin system (RAS) has been proposed to play a major role in causing the heart to hypertrophy during pressure overload. We examined whether blockade of this system by the angiotensin-converting enzyme (ACE) inhibitors enalapril (0.5 to 20 mg/kg p.o.) or ramipril (1.0 mg/kg p.o.) or the angiotensin receptor (AT1) antagonist losartan (3.0 mg/kg p.o.) could prevent pressure overload-induced hypertrophy. Pressure overload was produced by abdominal aortic constriction in rats. Cardiac hypertrophy was assessed by an increase in the ratio of left ventricular (LV) weight to body weight and total protein content of the left ventricle. Treatment with enalapril or ramipril, initiated 3 weeks after aortic banding and continued for 3 more weeks, failed to prevent the progression or cause regression of cardiac hypertrophy. Treatment for 6 weeks with ramipril initiated immediately after aortic banding also failed to prevent cardiac hypertrophy. Losartan treatment initiated 3 weeks after aortic banding and continued for 3 more weeks resulted in a slight but significant reduction in the extent of cardiac hypertrophy (45.6% hypertrophy in controls and 35.6% hypertrophy in losartan-treated animals, p < 0.05, n = 11 and 10, respectively). Surgical removal of bands 3 weeks after placement reduced cardiac hypertrophy to a greater extent than that observed in losartan-treated animals. These results suggest that angiotensin may not play a major role in causing pressure overload-induced hypertrophy or in maintaining such hypertrophy.

Topics: Angiotensin I; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta, Abdominal; Biphenyl Compounds; Blood Pressure; Body Weight; Cardiomegaly; Enalapril; Heart Ventricles; Imidazoles; Losartan; Male; Organ Size; Ramipril; Rats; Rats, Sprague-Dawley; Renin-Angiotensin System; Tetrazoles; Ventricular Function

We have studied the effect of ramipril (10 mg/kg daily by gastric gavage) on the development of neointima 2 and 14 days after injury to rat aorta with a balloon catheter. In treated animals, there was no significant inhibition of the early mitotic reaction after injury (synthesis of DNA, as reflected by aortic thymidine incorporation on the second day): the mean (95% confidence interval) was 3,553 (892) in the control group vs. 2,853 disintegrations/min/micrograms of DNA (555) in the treated group, 2 p greater than 0.15. However, ramipril decreased the amount of neointima formed 14 days after injury, as characterized by (a) a highly significant decrease of the intima to intima + media areas ratio [21.1 (2.4) vs. 13.7% (2.2), 2 p less than 10(-4]); (b) a significant decrease of intima-media wet weight [35.4 (1.0) vs. 30.9 mg (0.9), 2p less than 0.005]; and (c) without any significant effect on intima-media DNA content [96.3 (7.9) vs. 91.7 micrograms (5.7), 2p greater than 0.3]. These observations suggest that angiotensin converting enzyme inhibitors may not act mainly through an inhibition of smooth muscle cell proliferation. Other effects, such as inhibition of migration, hypertrophy, and matrix synthesis, should also be considered.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Body Weight; Bridged Bicyclo Compounds; Catheterization; DNA; Male; Ramipril; Rats; Rats, Inbred Strains; Thoracic Arteries

Both angiotensin converting enzyme (ACE) inhibition and sodium-diuresis lower blood pressure in spontaneously hypertensive rats (SHR). The purpose of the present study was to examine whether long-term therapy with ramipril (RA, and ACE inhibitor) would lower blood pressure more effectively and without adverse reactions in combination with the loop diuretics piretanide (PI) or furosemide (FU). Groups of 15 SHR each were treated once daily for 3 weeks by gavage with 1 and 10 mg/kg RA, 2 and 4 mg/kg PI, and 8 and 16 mg/kg FU alone and with 1 mg/kg RA in combination with each of these diuretics at both the high and low doses. Sustained and marked ACE inhibition with 10 mg/kg RA normalized BP, but this was accompanied with slightly impaired kidney function as assessed by increases in both urea and creatinine. Low-dose diuretic therapy, producing little diuresis, or treatment with 1 mg/kg RA, producing less sustained ACE inhibition were less effective on blood pressure and scarcely altered serum solute levels, except 4 mg/kg PI, which produced slight reductions in Na+, K+, Mg2+, and PO4(3-). Combined treatment with the 1 mg/kg RA with either diuretic given at low or high dose was well tolerated at much improved reduction in blood pressure compared to their effects individually and without changes in serum solute concentrations and without hemoconcentration. Thus, combined treatment with low doses of loop diuretics and ACE inhibitors that permit partial recovery of serum ACE activity during the 24 h after dosing synergistically lowers blood pressure without adverse reactions associated with larger doses of either therapy alone.

Topics: Aldosterone; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Body Weight; Bridged Bicyclo Compounds; Bridged-Ring Compounds; Diuretics; Electrolytes; Furosemide; Heart Rate; Hypertension; Male; Peptidyl-Dipeptidase A; Ramipril; Rats; Rats, Inbred SHR; Renin; Sulfonamides

Global and regional hemodynamic changes were assessed in 11 patients with congestive heart failure following the introduction of the novel angiotensin-converting enzyme inhibitor (ACEI), ramipril. All patients were stabilized on digitalis, furosemide, and a fixed diet, central hemodynamics and hormones having been stable over 2 control days. Ramipril resulted in significant falls in converting enzyme activity, angiotensin II, and aldosterone, with a rise in renin. Changes in regional blood flow were assessed 2 h following the first dose of ramipril at the time of maximal increase in global cardiac output (+27%, p less than 0.05), but prior to the maximal fall in systemic arterial pressure. Despite the fall in systemic arterial pressure, blood flow increases were noted in the renal (+93%, p less than 0.05), coronary (+10%), and cerebral (+5%) regions, while forearm blood flow was unchanged. Glomerular filtration rate fell (29%) and was associated with small rises of plasma creatinine and acute sodium retention. After 7 weeks of therapy we noted improvement in functional class (p less than 0.05), exercise time, and left ventricular ejection fraction. We conclude that during inhibition of angiotensin-converting enzyme activity by ramipril in patients with congestive heart failure, blood flow to the kidneys, heart, and brain is increased or preserved despite hypotension. Long-term therapy is associated with beneficial clinical effects.

Topics: Aged; Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Body Weight; Bridged Bicyclo Compounds; Bridged-Ring Compounds; Cardiac Output; Diet; Electrolytes; Female; Heart Failure; Hemodynamics; Hormones; Humans; Kidney; Male; Middle Aged; Ramipril; Regional Blood Flow

1. Streptozotocin diabetes was induced in Wistar-Kyoto rats fed a 50% protein diet. Animals were randomized to receive either the ACE inhibitor ramipril, 1 mg/L in drinking water (n = 7), or no treatment (n = 7) and were studied for 6 months. Blood glucose, body weight and glomerular filtration rate (GFR) were measured at 0, 1, 4, 8 and 16 weeks of diabetes and urinary albumin excretion was measured every 8 weeks. 2. In both groups, GFR increased significantly within 1 week of induction of diabetes (P less than 0.001) and thereafter remained stable. There was no difference in GFR between the treated and untreated groups. 3. Urinary albumin excretion increased progressively in both groups throughout the study. Ramipril treatment reduced albuminuria by approximately 50% at weeks 16 and 24 (P less than 0.01). 4. The amelioration of diabetic albuminuria by ACE inhibition, in the setting of high dietary protein intake, may have important implications for the treatment of human diabetic nephropathy.

Topics: Albuminuria; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Glucose; Blood Pressure; Body Weight; Bridged Bicyclo Compounds; Bridged-Ring Compounds; Diabetes Mellitus, Experimental; Diet; Dietary Proteins; Glomerular Filtration Rate; Male; Ramipril; Rats; Rats, Inbred WKY; Time Factors