ramipril and Insulin-Resistance

This review is based on the papers presented in the New England Journal of Medicine and the Lancet. Previous studies have suggested that blockade of the renin-angiotensin system may prevent diabetes in people with cardiovascular disease or hypertension. On the other hand, rosiglitazone, a thiazolidinedione, can reduce insulin resistance and might preserve insulin secretion. To asses prospectively the ability of these drugs to prevent type 2 diabetes in individuals at high risk for developing this condition. The results provide clear evidence, that among persons with impaired fasting glucose levels or impaired glucose tolerance, the use of 15 mg ramipril for 3 years does not significantly reduce the incidence of type 2 diabetes or death but does significantly increase regression to normoglycaemia. In the same population rosiglitazone at 8 mg daily for 3 years substantially reduces the incidence of type 2 diabetes and increases the regression to normoglycaemia.

Topics: Antihypertensive Agents; Blood Glucose; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Administration Schedule; Female; Humans; Hypoglycemic Agents; Incidence; Insulin Resistance; Male; Middle Aged; Prospective Studies; Ramipril; Randomized Controlled Trials as Topic; Rosiglitazone; Thiazolidinediones; Treatment Outcome

Hypertension in combination with clinically overt diabetes mellitus is recognized as a particularly powerful combination of risk factors that greatly increases cardiovascular vulnerability. There is also evidence that presumed pre-diabetic conditions such as insulin resistance, hyperinsulinaemia and compensatory hyperglycaemia may amplify overall cardiovascular risk in patients with hypertension, especially when encountered as part of the condition known as metabolic syndrome X (Reaven's syndrome). The long-term benefits of antihypertensive therapy may be compromised if these drugs exert adverse effects on metabolic parameters such as insulin sensitivity, or if they promote a transition from pre-diabetes to overt diabetes. Class differences in the effects of antihypertensives on metabolic indices may therefore be an important consideration when choosing treatment for patients who exhibit these characteristics. Experience from clinical trials suggests that drugs that target the renin-angiotensin system may have metabolic advantages over drugs such as beta-blockers and diuretics, but this conclusion has not been proved definitively. Moxonidine, which selectively targets imidazoline type-1 receptors in the sympathetic vasomotor centres of the rostral-ventrolateral medulla, is an effective antihypertensive and has been reported to exert favourable metabolic effects in preclinical and clinical studies. The MARRIAGE study (Moxonidine And Ramipril Regarding Insulin And Glucose Evaluation) will extend these preliminary observations by comparing the effects of moxonidine and the ACE inhibitor ramipril--and the combination of both drugs--on metabolic and haemodynamic parameters in patients with hypertension and impaired fasting glycaemia. A description is provided of the design and conduct of MARRIAGE.

Topics: Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Blood Glucose; Cardiovascular Diseases; Clinical Trials as Topic; Humans; Hypertension; Imidazoles; Imidazoline Receptors; Insulin Resistance; Metabolic Syndrome; Ramipril; Receptors, Drug; Risk

Topics: Angioplasty, Balloon, Coronary; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Arteriosclerosis; Cardiomegaly; Clinical Trials as Topic; Coronary Restenosis; Humans; Hypertension; Hypertension, Renal; Insulin Resistance; Losartan; Ramipril; Receptor, Angiotensin, Type 1

Plasma visfatin levels are elevated in diabetic nephropathy in parallel to the severity of proteinuria and glomerular filtration rate. The aim of this study was to find out whether the renin-angiotensin-aldosterone system (RAAS) blockage has any effect on the plasma visfatin levels.. Thirty-two patients with diabetic proteinuria (>500 mg/day) with a normal glomerular filtration rate (GFR) and 33 healthy subjects were enrolled. Patients were treated with ramipril 5 mg daily for 2 months. Proteinuria, GFR, high-sensitivity C-reactive protein (hsCRP), visfatin, flow-mediated dilatation (FMD) and homeostasis model assessment of insulin resistance (HOMA-IR) index measurements were performed both before and after the treatment.. The plasma visfatin, and hsCRP levels of the patients were significantly higher and the FMD was significantly lower (P < 0.001 for all). The visfatin levels were significantly correlated to FMD, systolic and diastolic blood pressures, proteinuria, eGFR, HOMA-IR and hsCRP. Ramipril treatment resulted in a significant decrease in plasma visfatin, proteinuria, hsCRP, HOMA-IR and increase in FMD (P < 0.001) in patients (P < 0.001 for all).. The present study suggests that plasma visfatin levels are related to the endothelial functions, inflammation and the severity of proteinuria in diabetic nephropathy. Treatment with ramipril causes a significant decrease in visfatin levels along with the improvement of proteinuria, endothelial dysfunction and inflammatory state in diabetic nephropathy.

Topics: Adult; Angiotensin-Converting Enzyme Inhibitors; Biomarkers; Blood Pressure; C-Reactive Protein; Cytokines; Diabetic Nephropathies; Endothelium, Vascular; Female; Glomerular Filtration Rate; Humans; Inflammation; Insulin Resistance; Male; Middle Aged; Nicotinamide Phosphoribosyltransferase; Proteinuria; Ramipril; Renin-Angiotensin System; Time Factors; Treatment Outcome; Vasodilation

Nonmodulating (NMHT) is a high-renin subtype of salt sensitive hypertension, which additionally develops insulin resistance and oxidative stress. Conversely, modulating hypertensives (MHT) normally regulates renal hemodynamics after high sodium intake without metabolic impairment. We postulate that telmisartan, an angiotensin receptor blocker with partial peroxisome proliferators-activated receptorgamma partial agonist, may improve insulin resistance compared with ramipril, an angiotensin-converting enzyme inhibitor (ACEI) in NMHT.. We studied 18 NMTH (32 +/- 5y nine men, BMI 29 +/- 3 kg/m2) and 16 MHT (34 +/- 4, 10 men, BMI 28 +/- 5 kg/m2) before and after the crossover administration of ramipril 10 mg (3 months) or telmisartan 80 mg (3 months). In each patient studied we measured, before and after each treatment period, office blood pressure, glycemia and insulinemia before and 60 and 120 min after a glucose overload (75 g), total cholesterol, high-density lipoprotein and low-density lipoprotein fractions, triglycerides and highly sensitive C-protein-reactive protein. After that, HOMA-IR Index was calculated.. Plasma renin activity was higher in NMHT 4.4 +/- 0.5 than MHT 2.6 +/- 0.9 ng.ml.h; P < 0.01. Blood pressure was similarly reduced either in MHT or NMHT by ramipril (MHT: from 159 +/- 10/102 +/- 4 to 142 +/- 6/93 +/- 3 mmHg, P < 0.05; NMHT: from 162 +/- 12/97 +/- 4 to 139 +/- 7/89 +/- 2 mmHg, P < 0.05) or telmisartan (MHT: from 154 +/- 8/96 +/- 5 to 137 +/- 6/88 +/- 4 mmHg, P < 0.05; NMHT: from 161 +/- 9/96 +/- 5 to 137 +/- 5/86 +/- 3 mmHg, P < 0.05). In NMHT, fasting glycemia (99 +/- 10 mg%) and insulinemia (16 +/- 4 microU%) and 120 min glycemia (110 +/- 2 mg%) and insulinemia (57 +/- 9 microU%) were higher than in MHT (fasting: 92 +/- 8 mg% and 9.2 +/- 2 mU%; 120 min: 95 +/- 5 and 21 +/- 5 microU%, P < 0.05). In MHT, after 3 months treatment with either ramipril or telmisartan no changes were found in fasting and 120 min glycemia and insulinemia. In NMHT, telmisartan, after 3 months treatment, significantly reduced fasting and 120 min insulinemia (fasting: 8.4 +/- 2, 120 min: 25 +/- 10 microU%; P < 0.01) compared either to basal values or ramipril treatment. Similarly, only in NMHT, compared with basal values and ramipril treatment, telmisartan improved the HOMA-IR index in both MHT (2.76 +/- 0.16 to 2.24 +/- 0.18, P < 0.05) and NMHT (from: 4.4 +/- 1 to 2.3 +/- 0.7) and triglyceride plasma levels (MHT: from 139 +/- 1.85 to 122 +/- 2.4 mg%, P < 0.05; NMHT: from: 223 +/- 12 to 146 +/- 10 mg%, P < 0.01). Finally, highly sensitive C-protein-reactive protein values were higher in NMHT (0.33 +/- 0.07 mg.dl) than in MHT (0.14 +/- 0.06 mg.dl; P < 0.01). Both treatments reduced highly sensitive C-protein-reactive protein in NMHT. (ramipril from 0.32 +/- 0.05 mg.dl to 0.26 +/- 0.06 m.dl (P < 0.05) and telmisartan from 0.34 +/- 0.05+/- to 0.20 +/- 0.05 mg.dl (P < 0.01).. Our data suggest that the improvement of the insulin sensitivity by telmisartan, instead of a similar effect on blood pressure shown by both drugs, could be ascribed to the PPAR agonistic action of telmisartan. This opens an interesting therapeutic approach for patients with hypertension and altered glycemic metabolism.

Topics: Adult; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Benzimidazoles; Benzoates; Blood Glucose; Blood Pressure; C-Reactive Protein; Cross-Over Studies; Female; Humans; Hypertension; Insulin Resistance; Lipids; Male; Oxidative Stress; PPAR gamma; Ramipril; Renin; Salt Tolerance; Telmisartan

Plasma adiponectin levels are well associated with metabolic syndrome. However, the relationship between hypertension and plasma adiponectin levels is not clear. Also, there is not enough data about the effects of different antihypertensive regimens on plasma adiponectin levels.. Ninety-six hypertensive patients (48 male, 48 female) who fulfil the diagnostic criteria of metabolic syndrome were enrolled. Patients were treated for 3 months with metoprolol (n = 18, 100 mg/day), amlodipine (n = 20, 10 mg/day), doxazosin (n = 18, 4 mg/day), ramipril (n = 20, 5 mg/day) and valsartan (n = 20, 80 mg/day). Blood biochemistry and plasma adiponectin concentrations were measured both before and after the study. Insulin resistance was measured by homeostasis assessment index (HOMA).. Plasma adiponectin levels were correlated with the total cholesterol (r = -0.244, P = 0.017), triglyceride (r = -0.306, P = 0.002), high-density lipoprotein-cholesterol (r = 0.286, P = 0.005), body mass index (r = -374, P < 0.001), systolic (r = -502, P < 0.001) and diastolic blood pressures (r = -235, P = 0.021). The independent predictors of plasma adiponectin levels were HOMA (beta = -0.199, P = 0.02), body mass index (beta = -0.313, P < 0.001) and systolic blood pressures (beta = -0.483, P < 0.001). Ramipril and valsartan increased the plasma adiponectin levels significantly higher than the other regimens (P < 0.05 for both) while metoprolol did not make a significant effect.. According to the results, plasma adiponectin levels are associated with the arterial blood pressures, body fat content and the lipid parameters in hypertensive patients with metabolic syndrome. The effects of antihypertensive drugs on plasma adiponectin levels are parallel to their effects on blood pressures and insulin sensitivities. The different effects of several regimens on plasma adiponectin levels and insulin sensitivities may account for the diversity of the cardiovascular outcomes in patients with hypertension.

Topics: Adiponectin; Adrenergic beta-Antagonists; Adult; Amlodipine; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Blood Pressure; Body Mass Index; Calcium Channel Blockers; Doxazosin; Female; Humans; Hypertension; Insulin Resistance; Lipids; Male; Metabolic Syndrome; Metoprolol; Middle Aged; Predictive Value of Tests; Prospective Studies; Ramipril; Tetrazoles; Time Factors; Treatment Outcome; Valine; Valsartan

The aim of this study was to find out whether the beneficial effects of the renin-angiotensin-aldosterone system (RAS) blockage in chronic kidney disease (CKD) has any relation with the alteration of asymmetric dimethylarginine (ADMA) levels.. Sixty-six nondiabetic patients with CKD and proteinuria and 36 healthy subjects were enrolled. Patients were treated with either ramipril 5 mg daily or valsartan 160 mg daily for 3 months. Proteinuria, ADMA, symmetric dimethyl arginine (SDMA), flow-mediated dilatation (FMD) and HOMA index measurements were performed both before and after the treatment.. ADMA, SDMA, hsCRP levels, HOMA index and proteinuria of patients were significantly higher (p < 0.001 for all) and FMD, L-arginine and L-arginine/ADMA ratio in CKD were significantly lower than controls. According to the multiple regression analysis, proteinuria levels were independently related to ADMA and SDMA levels.. Both drugs were equally effective in reducing elevated ADMA levels and improving endothelial dysfunction in CKD patients.

Topics: Adult; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Arginine; Biomarkers; Blood Glucose; C-Reactive Protein; Female; Glomerular Filtration Rate; Hemorheology; Humans; Insulin Resistance; Kidney Failure, Chronic; Lipids; Male; Middle Aged; Proteinuria; Ramipril; Renin-Angiotensin System; Tetrazoles; Valine; Valsartan; Vasodilation

This study was designed to investigate the effect of short-term ACE inhibitor treatment on insulin sensitivity and to examine possible underlying metabolic and haemodynamic effects in obese insulin-resistant subjects.. A randomised, double-blind placebo-controlled trial was performed in 18 obese insulin-resistant men (age, 53 +/- 2 years; BMI, 32.6 +/- 0.8 kg/m(2); homeostasis model assessment of insulin resistance, 5.6 +/- 0.5; systolic blood pressure [SBP], 140.8 +/- 3.2; diastolic blood pressure [DBP], 88.8 +/- 1.6 mmHg), who were free of any medication. The aim was to examine the effects of 2 weeks of ACE inhibitor treatment (ramipril, 5 mg/day) on insulin sensitivity, forearm blood flow, substrate fluxes across the forearm, whole-body substrate oxidation and intramuscular triacylglycerol (IMTG) content.. Ramipril treatment decreased ACE activity compared with placebo (-22.0 +/- 1.7 vs 0.2 +/- 1.1 U/l, respectively, p < 0.001), resulting in a significantly reduced blood pressure (SBP, -10.8 +/- 2.1 vs -2.7 +/- 2.0 mmHg, respectively, p = 0.01; DBP, -10.1 +/- 1.3 vs -4.2 +/- 2.1 mmHg, respectively, p = 0.03). Ramipril treatment had no effect on whole-body insulin-mediated glucose disposal (before: 17.9 +/- 2.0, after: 19.1 +/- 2.4 micromol kg body weight(-1) min(-1), p = 0.44), insulin-mediated glucose uptake across the forearm (before: 1.82 +/- 0.39, after: 1.92 +/- 0.29 micromol 100 ml forearm tissue(-1) min(-1), p = 0.81) and IMTG content (before: 45.4 +/- 18.8, after: 48.8 +/- 27.5 micromol/mg dry muscle, p = 0.92). Furthermore, the increase in carbohydrate oxidation (p < 0.001) and forearm blood flow (p < 0.01), and the decrease in fat oxidation (p < 0.001) during insulin stimulation were not significantly different between treatments.. Short-term ramipril treatment adequately reduced ACE activity and blood pressure, but had no significant effects on insulin sensitivity, forearm blood flow, substrate fluxes across the forearm, whole-body substrate oxidation and IMTG content in obese insulin-resistant subjects.

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Blood Glucose; Blood Pressure; Double-Blind Method; Fatty Acids, Nonesterified; Glucose Clamp Technique; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Middle Aged; Placebos; Ramipril

Mechanisms underlying biological effects of statin and angiotensin-converting enzyme inhibitor therapies differ. Therefore, we compared vascular and metabolic responses to these therapies either alone or in combination in patients with type 2 diabetes. This was a randomized, double-blind, placebo-controlled crossover trial with 3 treatment arms (each 2 months) and 2 washout periods (each 2 months). Fifty patients with type 2 diabetes were given simvastatin 20 mg and placebo, simvastatin 20 mg and ramipril 10 mg, or ramipril 10 mg and placebo daily during each 2-month treatment period. Ramipril alone or combined therapy significantly reduced blood pressure when compared with simvastatin alone. When compared with ramipril alone, simvastatin alone or combined therapy significantly improved the lipoprotein profile. All 3 treatment arms significantly improved flow-mediated dilator response to hyperemia and reduced plasma levels of malondialdehyde relative to baseline measurements. However, these parameters were changed to a greater extent with combined therapy when compared with simvastatin or ramipril alone (P<0.001 by ANOVA). When compared with simvastatin or ramipril alone, combined therapy significantly reduced high-sensitivity C-reactive protein levels (P=0.004 by ANOVA). Interestingly, combined therapy or ramipril alone significantly increased plasma adiponectin levels and insulin sensitivity relative to baseline measurements. These changes were significantly greater than in the group treated with simvastatin alone (P<0.015 by ANOVA). Ramipril combined with simvastatin had beneficial vascular and metabolic effects when compared with monotherapy in patients with type 2 diabetes.

Topics: Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; C-Reactive Protein; Cross-Over Studies; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Therapy, Combination; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Insulin Resistance; Lipids; Malondialdehyde; Ramipril; Simvastatin; Vasodilation

ACE inhibition reduces plasminogen activator inhibitor-1 (PAI-1), a risk factor for myocardial infarction, whereas the effect of angiotensin receptor antagonism on PAI-1 is uncertain. The present study compares the time course of effects of ACE inhibition and angiotensin type 1 (AT1) receptor antagonism on morning plasma PAI-1 antigen. Blood pressure and endocrine, metabolic, and fibrinolytic variables were measured in 20 insulin-resistant (defined by fasting glucose >8.3 mmol/L, body mass index >28 kg/m2, or fasting serum triglyceride > or =2.8 mmol/L) hypertensive subjects (mean age, 47.9+/-2.1 years) (1) before and after 1 week of hydrochlorothiazide 12.5 mg/d, and (2) before and 1, 3, 4, and 6 weeks after addition of ramipril (escalated to 10 mg/d) or losartan (escalated to 100 mg/d). Hydrochlorothiazide decreased systolic (P=0.011) and diastolic (P=0.019) pressure. Ramipril (from 133.6+/-5.1/94.5+/-2.4 to 127.0+/-3.1/91.4+/-3.3 mm Hg) or losartan (from 137.0+/-3.9/93.1+/-2.9 to 123.7+/-2.6/86.4+/-2.1 mm Hg) further reduced systolic (P=0.009) and diastolic (P=0.037) pressure. The pressure effects of the 2 drugs were similar. Hydrochlorothiazide increased plasma PAI-1 (P=0.013) but not tissue-type plasminogen activator (tPA) (P=0.431) antigen. Addition of either ramipril or losartan significantly decreased plasma PAI-1 antigen (P=0.046). However, the effect of losartan on PAI-1 antigen was not sustained throughout the 6-week treatment period, such that there was a significant drugxtime interaction (P=0.043). tPA antigen decreased during either ramipril or losartan (P=0.032), but tPA activity decreased only during losartan (P=0.018). Short-term interruption of the renin-angiotensin-aldosterone system by either ACE inhibition or AT1 receptor antagonism decreases PAI-1 antigen, but the duration of this effect is greater for ACE inhibition than for AT1 receptor antagonism.

Topics: Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Blood Glucose; Blood Pressure; Diuretics; Dose-Response Relationship, Drug; Drug Therapy, Combination; Female; Humans; Hydrochlorothiazide; Hypertension; Insulin; Insulin Resistance; Losartan; Male; Middle Aged; Plasminogen Activator Inhibitor 1; Ramipril; Receptor, Angiotensin, Type 1; Renin-Angiotensin System; Sodium Chloride Symporter Inhibitors; Tissue Plasminogen Activator; Treatment Outcome

Human essential hypertension is a complex trait with poorly understood genetic determination. Insulin resistance is frequently associated with this trait.. To determine whether a potentially pathogenic feature of the insulin-resistant state, circulating amylin (islet amyloid polypeptide, co-released with insulin from pancreatic islet beta-cells), is already increased in prehypertensive individuals (normotensive persons at genetic risk of hypertension because of family history), whether such individuals already differ in their amylin response to beta-cell stimulation, and whether plasma amylin concentration is heritable. Such features could establish increased circulating amylin as a hereditary 'intermediate phenotype' useful in genetic analyses of hypertension.. Plasma amylin and insulin were measured in 283 medication-free individuals stratified by blood pressure status (82 hypertensive and 201 normotensive), and genetic risk (family history) of hypertension. Differences in means were tested by ANOVA, variances by F test, and frequency distributions by maximum likelihood analysis. Co-release of amylin and insulin was provoked by intravenous infusion of mixed amino acids. The effect of antihypertensive treatment was evaluated after monotherapy with either angiotensin converting enzyme inhibition or calcium-channel blockade in hypertension.. Plasma amylin was increased in hypertension (P= 0.027), and body mass index was a strong predictor of increased circulating amylin (P = 0.0001). Plasma amylin and plasma renin activity were not correlated (P = 0.395), and effective antihypertensive monotherapy with either angiotensin converting enzyme inhibition or calcium-channel blockade did not affect either amylin (P = 0.87-0.97) or insulin (P= 0.55-0.59). Among normotensive individuals, those at genetic risk of hypertension (with positive family history) already had increased concentrations of amylin (P< 0.001), despite exhibiting no difference in blood pressure or body mass index compared with the family-history-negative group; however, among normotensive individuals, both family history (P = 0.043) and body mass index (P= 0.0059) were significant predictors of increased concentrations of amylin. By maximum likelihood analysis, plasma amylin was distributed heterogeneously in the normotensive individuals, with two modes best explaining the distribution (chi2 = 77.4, P< 0.001), and family-history-positive individuals completely accounting for the upper mode (chi2 = 4.63, P = 0.031). Family-history-positive normotensive individuals showed greater plasma amylin concentrations both before and during beta-cell stimulation by amino acid infusion (P = 0.014). Black (n = 111) and white (n = 172) individuals did not differ in mean (P = 0.946) or variance (P = 0.172) of plasma amylin concentrations.. These results suggest that plasma amylin concentration is in part determined by heredity. Both basal and stimulated plasma amylin excess may identify a subgroup of individuals bearing an inherited predisposition to hypertension. Measurement of amylin might identify a useful 'intermediate phenotype' in the genetic analysis of essential hypertension and its relationship to insulin resistance.

Topics: Adult; Amino Acids; Amyloid; Antihypertensive Agents; Blood Pressure; Body Mass Index; Female; Genetic Predisposition to Disease; Humans; Hypertension; Insulin; Insulin Resistance; Islet Amyloid Polypeptide; Male; Middle Aged; Ramipril; Risk Factors

To assess the effects of angiotensin converting enzyme (ACE) inhibitor on insulin action in obesity, five normotensive non-diabetic obese women were examined on two occasions as part of a double-blind, randomized, cross-over study involving ten days of treatment with either 1.25 mg ramipril or placebo. The study consisted of a euglycaemic hyperinsulinaemic clamp (two periods of insulin infusion at rates of 0.4 and 1 mU/kg/min, 2 h for each step) combined with indirect calorimetry. The most notable results involved a significantly faster time-course of glucose infusion rates during the first 30 min of each insulin infusion period [analysed by calculating slopes (S1 and S2)] after ramipril than placebo administration. The mean glucose infusion rates reached during the last 30 min of each insulin infusion period (G1 and G2), as well as the increases in carbohydrate oxidation rates during the clamp (C1-C0 and C2-C0) and the decreases in plasma nonesterified fatty acids (A0-A1 and A0-A2), were not significantly different after ramipril and placebo. According to robust principal component analysis of S1, S2, G1, G2, C1, C2, A1 and A2 (orthogonally to C0 and A0), insulin sensitivity was improved with ramipril as compared to placebo (p = 0.013). This study strongly suggests that a low dose of an ACE inhibitor increases the activation phase of insulin action in normotensive nondiabetic obese patients and may accelerate insulin action.

Topics: Adult; Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Cross-Over Studies; Double-Blind Method; Female; Glucose Clamp Technique; Humans; Infusions, Intravenous; Insulin Resistance; Middle Aged; Obesity; Oxidation-Reduction; Pilot Projects; Ramipril; Time Factors

Chronic restraint stress (CRS) is known to cause various behavioural and biochemical alterations, leading to several negative health outcomes. The present study was designed to explore the impact of inhibiting Renin angiotensin aldosterone system (RAAS) and inflammatory pathways in stress pathophysiology. In the present study, male LACA mice were subjected to restraint stress daily for 30 days. Losartan, nimesulide, ramipril, minocycline and their combinations were administered 45min prior to restraint stress daily and their effects were observed. Restraint stressed mice depicted depression like behavior along with increased oxidative stress markers in their brains. CRS induced insulin resistance depicted by hyperglycemia, hyperinsulinemia, hypercholesteremia, increased glycosylated hemoglobin and HOMA-IR. Besides, treatment with losartan, nimesulide, ramipril and minocycline significantly restored the behavioural and biochemical alterations and improved insulin sensitivity in stressed mice. Combination treatments synergistically reversed depression like behavior and decreased plasma glucose levels. Moreover they restored insulin levels, glycosylated hemoglobin levels and HOMA-IR values to the normal. This study signifies the synergistic effect of simultaneously blocking RAS and inflammatory pathways in stress pathophysiology.

Topics: Animals; Anti-Inflammatory Agents; Biomarkers; Insulin Resistance; Losartan; Male; Mice; Ramipril; Renin-Angiotensin System; Stress, Psychological

This study aims to investigate the effects of ramipril (RPL) on endothelial dysfunction associated with diabetes mellitus using cultured human aortic endothelial cells (HAECs) and a type 2 diabetic animal model. The effect of RPL on vasodilatory function in fat-fed, streptozotocin-treated rats was assessed. RPL treatment of 8 weeks alleviated insulin resistance and inhibited the decrease in endothelium-dependent vasodilation in diabetic rats. RPL treatment also reduced serum advanced glycation end products (AGE) concentration and rat aorta reactive oxygen species formation and increased aorta endothelium heme oxygenase-1 (HO-1) expression. Exposure of HAECs to high concentrations of glucose induced prolonged oxidative stress, apoptosis, and accumulation of AGEs. These effects were abolished by incubation of ramiprilat (RPT), the active metabolite of RPL. However, treatment of HAECs with STO-609, a CaMKKβ (Ca(2+)/calmodulin-dependent protein kinase kinase-β) inhibitor; compound C, an AMPK (AMP-activated protein kinase) inhibitor; and Zn(II)PPIX, a selective HO-1 inhibitor, blocked these beneficial effects of RPT. In addition, RPT increased nuclear factor erythroid 2-related factor-2 (Nrf-2) nuclear translocation and activation in a CaMKKβ/AMPK pathway-dependent manner, leading to increased expression of the Nrf-2-regulated antioxidant enzyme, HO-1. The inhibition of CaMKKβ or AMPK by pharmaceutical approach ablated RPT-induced HO-1 expression. Taken together, RPL ameliorates insulin resistance and endothelial dysfunction in diabetes via reducing oxidative stress. These effects are mediated by RPL activation of CaMKK-β, which in turn activates the AMPK-Nrf-2-HO-1 pathway for enhanced endothelial function.

Topics: AMP-Activated Protein Kinases; Animals; Aorta; Apoptosis; Benzimidazoles; Calcium-Calmodulin-Dependent Protein Kinase Kinase; Cells, Cultured; Diabetes Mellitus, Experimental; Endothelial Cells; Enzyme Activation; Glucose; Glycation End Products, Advanced; Heme Oxygenase (Decyclizing); Humans; Insulin Resistance; Male; Naphthalimides; NF-E2-Related Factor 2; Oxidative Stress; Phosphorylation; Protein Kinase Inhibitors; Protoporphyrins; Pyrazoles; Pyrimidines; Ramipril; Rats; Reactive Oxygen Species; Signal Transduction; Vasodilation

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

Beneficial effects of an antioxidant (N-acetyl-L-cysteine, NAC) and an angiotensin I-converting enzyme (ACE) inhibitor (ramipril) were assessed in a rat model of insulin resistance induced by 10% glucose feeding for 20 weeks. Treatments with NAC (2 g/kg per day) and ramipril (1 mg/kg per day) were initiated at 16 weeks in the drinking fluid. Systolic blood pressure, plasma levels of insulin and glucose, and insulin resistance were significantly higher in rats treated with glucose for 20 weeks. This was associated with a higher production of superoxide anion and NADPH oxidase activity in aorta and liver and with a marked reduction in protein expression of skeletal muscle insulin receptor substrate-1 (IRS-1) in the gastrocnemius muscle. NAC prevented all these alterations. Although ramipril also reversed high blood pressure, it had a lesser effect on insulin resistance (including IRS-1) and blocked superoxide anion production only in aorta. Ramipril, in contrast to NAC, did not reduce NADPH oxidase activity in aorta and liver or plasma levels of 4-hydroxynonenal and malondialdehyde. Results suggest that the inhibition of the oxidative stress in hypertensive and insulin-resistant states contributes to the therapeutic effects of NAC and ramipril. Whereas NAC exerts effective antioxidant activity in multiple tissues, ramipril appears to preferentially target the vasculature.

Topics: Acetylcysteine; Aldehydes; Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta, Thoracic; Blood Pressure; Diet; Free Radical Scavengers; Glucose; Hypertension; Insulin Receptor Substrate Proteins; Insulin Resistance; Lipid Peroxidation; Liver; Male; Malondialdehyde; Muscle, Skeletal; NADPH Oxidases; Oxidative Stress; Oxygen Consumption; Ramipril; Rats; Rats, Wistar

Diabetes mellitus (DM) is a worldwide epidemic. Its prevalence is rapidly increasing in both developing and developed countries. Coronary heart disease (CHD) is highly prevalent and is the major cause of morbidity and mortality in patients with diabetes. Individuals with prediabetes states, with or without known CHD, should undergo lifestyle modifications aimed at preventing DM. In patients with CHD and DM, routine use of aspirin and an angiotensin-converting enzyme inhibitor, along with strict glycemic, blood pressure, and lipid control, is strongly recommended. Intense insulin therapy may be needed for glycemic control, and high-dose statin therapy may be needed for lipid control. For blood pressure control, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are considered first-line therapy. Noncompliance with medications and/or lifestyle measures and underprescription of evidence-based therapies remain important unsolved problems.

Topics: Antihypertensive Agents; Cholesterol, HDL; Cholesterol, LDL; Coronary Artery Disease; Diabetes Mellitus; Diabetic Angiopathies; Humans; Hyperglycemia; Hypoglycemic Agents; Hypolipidemic Agents; Insulin Resistance; Life Style; Myocardial Infarction; Obesity; Pioglitazone; Piperidines; Platelet Aggregation Inhibitors; Prediabetic State; Pyrazoles; Ramipril; Rimonabant; Risk Assessment; Thiazolidinediones; Triglycerides; Weight Loss

Topics: Angiotensin-Converting Enzyme Inhibitors; Blood Glucose; Diabetes Mellitus; Humans; Hypertension; Incidence; Insulin Resistance; Ramipril

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

ACE inhibitors (ACEIs) improve insulin resistance and prevent type 2 diabetes, possibly mediated by inhibition of bradykinin (BK) degradation. The vasopeptidase inhibitor omapatrilat (OMA) raises BK to a greater extent than ACEIs by dual enzyme inhibition, whereas its insulin-sensitizing effects and mechanisms have not been investigated.. We compared the insulin-sensitizing effects of OMA, ramipril (an ACEI), losartan (an angiotensin II type 1 receptor blocker), and placebo by 2-step euglycemic hyperinsulinemic clamp in insulin-resistant Zucker fatty rats (n=6 to 7 in each group). OMA resulted in a lower rate of endogenous glucose production than placebo at baseline (35+/-5 versus 54+/-4 mmol x kg(-1) x min(-1), P<0.01), greater suppression of endogenous glucose production by low-dose insulin (73+/-11% versus 27+/-18%, P<0.05), and greater glucose disposal at high-dose insulin (135+/-5 versus 92+/-4 mmol x kg(-1) x min(-1), P<0.01). Ramipril tended to improve insulin sensitivity, but losartan did not. OMA significantly increased 2-deoxyglucose uptake by myocardium, fat, and skeletal muscle. Ramipril increased 2-deoxyglucose uptake only by some skeletal muscles, but losartan did not. The insulin-sensitizing effects of OMA were blocked significantly by HOE-140 (a BK, B2 receptor antagonist) and NG-nitro-L-arginine methyl ester (a nitric oxide synthase inhibitor) in all tissues except myocardium.. OMA induces profound insulin sensitization and increases myocardial glucose uptake in Zucker fatty rats. This effect is greater than that of ramipril and probably occurs at least in part via stimulation of the B2 receptor. OMA has the potential for greater type 2 diabetes prevention than ACEI.

Topics: Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Biological Transport; Blood Glucose; Bradykinin; Bradykinin Receptor Antagonists; Drug Synergism; Enzyme Inhibitors; Glucose; Glucose Clamp Technique; Insulin; Insulin Resistance; Losartan; Male; Myocardium; Neprilysin; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase; Protease Inhibitors; Pyridines; Ramipril; Rats; Rats, Zucker; Receptor, Angiotensin, Type 1; Receptor, Bradykinin B2; Thiazepines

Topics: Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Blood Glucose; Clinical Trials as Topic; Comorbidity; Confidence Intervals; Diabetic Nephropathies; Glucose Tolerance Test; Humans; Hypertension; Insulin Resistance; Odds Ratio; Prediabetic State; Prevalence; Prospective Studies; Ramipril; Risk Factors

To investigate mechanisms by which angiotensin converting enzyme (ACE)-inhibition increases insulin sensitivity, spontaneously hypertensive (SH) rats were treated with or without ramipril (1 mg/kg per day) for 12 weeks. Insulin binding and protein levels of insulin receptor substrate-1 (IRS-1), p85-subunit of phosphatidylinositol 3'-kinase (p85) and Src homology 2 domain-containing phosphatase-2 (SHP2) were then determined in hindlimb muscle and liver. Additionally, protein tyrosine phosphatase (PTPase) activities towards immobilized phosphorylated insulin receptor or phosphorylated IRS-1 of membrane (MF) and cytosolic fractions (CF) of these tissues were measured. Ramipril treatment increased IRS-1-protein content in muscle by 31+/-9% (P<0.05). No effects were observed on IRS-1 content in liver or on insulin binding or protein expression of p85 or SHP2 in both tissues. Ramipril treatment also increased dephosphorylation of insulin receptor by muscle CF (22.0+/-1.0%/60 min compared to 16.8+/-1.5%/60 min; P<0.05), and of IRS-1 by liver MF (37.2+/-1.7%/7.5 min compared to 33.8+/-1.7%/7.5 min; P<0.05) and CF (36.8+/-1.0%/7.5 min compared to 33.2+/-1.0%/7.5 min; P<0.05). We conclude that the observed effects of ACE-inhibition by ramipril on the protein expression of IRS-1 and on PTPase activity might contribute to its effect on insulin sensitivity.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blotting, Western; Insulin Receptor Substrate Proteins; Insulin Resistance; Liver; Male; Muscle, Skeletal; Phosphatidylinositol 3-Kinases; Phosphoproteins; Protein Phosphatase 2; Protein Serine-Threonine Kinases; Protein Tyrosine Phosphatases; Ramipril; Rats; Rats, Inbred SHR; Receptor, Insulin

To assess the effect of ramipril on indicators of glucose metabolism, incl. insulin resistance, on renal function with microalbuminuria, changes of some echocardiographic signs of hypertrophy and compliance of the left ventricle in patients with hypertension and type II diabetes mellitus.. The authors examined 32 patients with hypertension grade I and II and with diabetes type II, who had ramipril, 2.5-10 mg/day, for a period of six months. The examination before and after long-term treatment comprised basic biochemical sampling incl. concentrations of immunoreactive insulin, C-peptide and glycated haemoglobin and also complete functional examination of the kidneys, incl. microalbuminuria. Echocardiographic examination was focused on assessment of signs of hypertrophy and compliance of the left ventricle. Treatment of diabetes was not changed in the course of 6 months.. In addition to the anticipated drop of blood pressure a declining trend of insulin resistance was recorded, there was a significant decline of microalbuminuria and a rise of natriuresis, the left ventricle mass declined and its compliance improved.. Ramipril one of the inhibitors of angiotensin converting enzyme is an effective and useful medication for type II diabetics suffering from hypertension.

Topics: Adult; Aged; Albuminuria; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Blood Glucose; Diabetes Mellitus, Type 2; Female; Heart; Humans; Hypertension; Insulin Resistance; Kidney; Male; Middle Aged; Natriuresis; Ramipril; Ventricular Function, Left