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Query: UMLS:C0011849 (diabetes)
277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of the present study was to compare the antihypertrophic effects of blockade of the renin-angiotensin system (RAS), vasopeptidase inhibition and calcium channel antagonism on cardiac and vascular hypertrophy in diabetic spontaneously hypertensive rats (SHR). SHR with streptozotocin-induced diabetes were treated with one of the following therapies for 32 weeks: the angiotensin-converting enzyme (ACE) inhibitor captopril (100 mg/kg); the angiotensin AT(1) receptor antagonist valsartan (30 mg/kg); a combination of captopril with valsartan; the vasopeptidase inhibitor mixanpril (100 mg/kg); or the calcium channel antagonist amlodipine (6 mg/kg). Systolic blood pressure and cardiac and mesenteric artery hypertrophy were assessed. Mean systolic blood pressure in diabetic SHR (200+/-5 mmHg) was reduced by captopril (162+/-5 mmHg), valsartan (173+/-5 mmHg), mixanpril (176+/-2 mmHg) and amlodipine (159+/-4 mmHg), and was further reduced by the combination of captopril with valsartan (131+/-5 mmHg). Captopril, valsartan and mixanpril reduced heart and left ventricle weights by approx. 10%. The combination of captopril and valsartan further reduced heart weight (-24%) and left ventricular weight (-29%). Amlodipine did not affect cardiac hypertrophy. Only mixanpril and the combination of captopril and valsartan significantly reduced mesenteric weight. The mesenteric wall/lumen ratio was reduced by all drugs, and to a greater extent by the combination of captopril and valsartan. We conclude that optimizing the blockade of vasoconstrictive pathways such as the RAS, particularly with the combination of ACE inhibition and AT(1) receptor antagonism, is associated with antitrophic effects in the context of diabetes and hypertension. In contrast, calcium channel blockade, despite similar effects on blood pressure, confers less antitrophic effects in the diabetic heart and blood vessels.
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PMID:Cardiovascular hypertrophy in diabetic spontaneously hypertensive rats: optimizing blockade of the renin-angiotensin system. 1265 75

Type 2 diabetes mellitus is becoming a major health problem associated with excess morbidity and mortality. As the prevalence of type 2 diabetes is rapidly increasing, prevention of the disease should be considered as a key objective in the near future. Besides lifestyle changes, various pharmacological treatments have proven their efficacy in placebo-controlled clinical trials, including antidiabetic drugs such as metformin, acarbose and troglitazone, or antiobesity agents such as orlistat. Arterial hypertension, a clinical entity in which insulin resistance is common, is strongly associated with type 2 diabetes and may precede the disease by several years. While antihypertensive agents such as diuretics or beta-adrenoceptor antagonists may worsen insulin resistance and impair glucose tolerance, newer antihypertensive agents exert neutral or even slightly positive metabolic effects. Numerous clinical trials have investigated the effects of ACE inhibitors or angiotensin II receptor antagonists (ARAs) on insulin sensitivity in hypertensive patients, with or without diabetes, with no consistent results. Almost half of the studies with ACE inhibitors in hypertensive nondiabetic individuals demonstrated a slight but significant increase in insulin sensitivity as assessed by insulin-stimulated glucose disposal during a euglycaemic hyperinsulinaemic clamp, while the other half failed to reveal any significant change. The effects of ARAs on insulin sensitivity are neutral in most studies. Mechanisms of improvement of glucose tolerance and insulin sensitivity through the inhibition of the renin-angiotensin system (RAS) are complex. They may include improvement of blood flow and microcirculation in skeletal muscles and, thereby, enhancement of insulin and glucose delivery to the insulin-sensitive tissues, facilitating insulin signalling at the cellular level and improvement of insulin secretion by the beta cells. Six recent large-scale clinical studies reported a remarkably consistent reduction in the incidence of type 2 diabetes in hypertensive patients treated with either ACE inhibitors or ARAs for 3-6 years, compared with a thiazide diuretic, beta-adrenoceptor antagonist, the calcium channel antagonist amlodipine or even placebo. The relative risk reduction averaged 14% (p = 0.034) in the CAPPP (Captopril Prevention Project) with captopril compared with a thiazide or beta1-adrenoceptor antagonist, 34% (p < 0.001) in the HOPE (Heart Outcomes Prevention Evaluation) study with ramipril compared with placebo, 30% (p < 0.001) in the ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) with lisinopril compared with chlortalidone, 25% (p < 0.001) in the LIFE (Losartan Intervention For Endpoint reduction in hypertension study) with losartan compared with atenolol, and 25% (p = 0.09) in the SCOPE (Study on Cognition and Prognosis in the Elderly) with candesartan cilexetil compared with placebo, and 23% (p < 0.0001) in the VALUE (Valsartan Antihypertensive Long-term Use Evaluation) trial with valsartan compared with amlodipine. All these studies considered the development of diabetes as a secondary endpoint, except the HOPE trial where it was a post hoc analysis. These encouraging observations led to the initiation of two large, prospective, placebo-controlled randomised clinical trials whose primary outcome is the prevention of type 2 diabetes: the DREAM (Diabetes REduction Approaches with ramipril and rosiglitazone Medications) trial with the ACE inhibitor ramipril and the NAVIGATOR (Nateglinide And Valsartan in Impaired Glucose Tolerance Outcomes Research) trial with the ARA valsartan. Finally, ONTARGET (ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial) will also investigate as a secondary endpoint whether it is possible to prevent the development of type 2 diabetes by blocking the RAS with either an ACE inhibitor or an ARA or a combination of both. Thus, the recent consistent observations of a 14-34% reduction of the development of diabetes in hypertensive patients receiving ACE inhibitors or ARAs are exciting. From a theoretical point of view, they emphasise that there are many aspects of the pathogenesis, prevention and treatment of type 2 diabetes that still need to be uncovered. From a practical point of view, they may offer a new strategy to reduce the ongoing epidemic and burden of type 2 diabetes.
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PMID:Prevention of type 2 diabetes mellitus through inhibition of the Renin-Angiotensin system. 1551 53

Nitric oxide (NO) is a potent regulator in the cardiovascular system; it is generated by the nitric oxide synthase (NOS) family of proteins. NO produced in endothelial cells plays a crucial role in vascular functions. The aim of this study was to clarify the effect of diabetes on aortic NO synthesis in a model of genetic hypertension and determine whether captopril modulates this effect. Diabetes was induced in ten weeks old spontaneously hypertensive rats (SHR) by streptozotocin injection. The rats were allocated into 3 groups: control group 1, non-diabetic SHR; group 2, diabetic SHR; group 3, diabetic SHR group receiving captopril at 80 mg/kg in drinking water for 4 weeks. Mean blood pressure (MBP) was measured once a week by tail-cuff method. Aortic NO metabolities (nitrite/nitrate) and endothelial NOS (NOS-3) were assayed by Griess reaction and by immunoblotting and immunohistochemistry, respectively. There was a significant decrease in nitrite/nitrate (NOx) in aortas of diabetic SHR compared with controls. The decrease of aortic NOx in diabetic SHR was accompanied by a decrease in NOS-3 expression. Captopril treatment reduced MBP without affecting either NOx level or NOS-3 expression in aortas of diabetic SHR. We conclude that STZ-induced diabetes decreased NO in aortas of SHR that may reflect endothelial cell dysfunction; captopril administration decreased MBP without affecting NO level in aortas of diabetic SHR which suggest that the blood pressure-lowering effects of captopril were independent of NO.
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PMID:Effect of diabetes on aortic nitric oxide synthesis in spontaneously hypertensive rats; does captopril modulate this effect? 1589 Mar 70

We present an unusual patient who simultaneously had severe renal artery stenosis RAS and Cushing's syndrome. The case highlights the difficulty of reaching a specific diagnosis of Cushing's syndrome and the possible interaction between Cushing's syndrome and some other concurrent illnesses that this patient had. A 37-year old man presented with severe hypertension HTN and uncontrolled diabetes mellitus DM without clear physical signs of Cushing's syndrome. He was found to have severe osteoporosis, proximal myopathy, several cutaneous warts, tinea versicolor, and chronic viral hepatitis. Captopril-stimulated renal scan and renal artery angiogram revealed severe RAS. Partial balloon dilatation of RAS led to improvement in HTN. Unexpectedly, urine free cortisol 24 hour was found extremely high. Serum adrenocorticotropic hormone ACTH was also elevated and high dose dexamethasone suppression tests were inconclusive. Several imaging studies failed to localize the source of ACTH. Despite normal MRI of the pituitary gland, bilateral inferior petrosal sinus sampling IPSS localized the source of ACTH secretion to the right side of the pituitary gland and right anterior hemihypophysectomy resulted in cure of Cushing's disease, HTN, DM, and tinea versicolor with significant improvement in cutaneous warts, osteoporosis, and chronic hepatitis. In conclusion, RAS and Cushing's syndrome may occur together. Significant hypercortisolemia can occur without clear signs of Cushing's syndrome. Controlling hypercortisolemia is of paramount importance when treating chronic infections in patients with Cushing's syndrome.
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PMID:Severe hypertension secondary to renal artery stenosis and Cushing's syndrome. 1590 Mar 83

The aim of the study was to evaluate the effects of the non-dihydropyridine calcium antagonist (NDCA) diltiazem on the development of urinary albumin excretion (UAE) in type 2 hypertensive diabetic patients with persistent microalbuminuria despite ACE inhibitor treatment. Thirty-six type 2 diabetic hypertensive patients with microalbuminuria persisting after at least 1 year of treatment with ACE inhibitors were randomized to receive captopril (n=22) or combined therapy with captopril and 120 mg diltiazem (n=14) for 2 years. Captopril dose was individualized according to blood pressure. Changes in UAE, blood pressure, and metabolic control were monitored to analyze the influence of the addition of diltiazem on progression of diabetic nephropathy. In patients treated with captopril and diltiazem, absolute UAE did not change during the study (baseline: 101 mg/24 h, range 39-298; 2 years after randomization: 74 mg/24 h, range 12-665). In contrast, UAE increased in patients treated with captopril monotherapy (baseline: 118 mg/24 h, range 32-282; 2 years after randomization: 164 mg/24 h, range 15-1161, p<0.05). In addition, fewer patients in the captopril/diltiazem group progressed to macroalbuminuria (eight patients in captopril group and one in captopril/diltiazem group, p<0.05). The beneficial effects of the addition of diltiazem were independent of blood pressure and metabolic control. We suggest that the combination of ACE inhibitors and NDCA should be considered in type 2 microalbuminuric patients at high risk for progression to established diabetic nephropathy.
Diabetes Res Clin Pract 2005 Oct
PMID:Renoprotective effect of diltiazem in hypertensive type 2 diabetic patients with persistent microalbuminuria despite ACE inhibitor treatment. 1612 18

One-quarter of adult population in different world regions are reported to live with hypertension, of whom, a high percentage had a diabetes mellitus (DM). This co-morbid state is believed to act synergistically on accelerating the long-term diabetic complications. Therefore, adequate treatment of high blood pressure is essential for diabetic patients, and should be always directed to their benefits. Albumin glycation is still the most important explanation for the pathogenesis of chronic diabetic complications. Our in vitro experiments induce non-enzymatic glycation of bovine serum albumin (BSA) under physiological conditions. The levels of advanced glycation end products (AGEs) were measured by their characteristic intrinsic fluorescence. Additions of captopril at concentrations from 5 to 50 microM caused 10-47% reduction in the formation of AGEs. Captopril binding properties of native and glycosylated BSA were characterized, and its affinity towards the native albumin was unaltered by the in vitro glycation. Therefore, we concluded that captopril could protect against albumin glycation, and it has a similar binding affinities towards native and glcosylated protein. Anti-glycation effect may help to attenuate the serious long-term diabetes related complications. Besides, the unchanged pharmacokinetic parameters provide an essential extra beneficial effect for diabetic hypertensive patients.
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PMID:Protective ability and binding affinity of captopril towards serum albumin in an in vitro glycation model of diabetes mellitus. 1646 67

Pravastatin, irbesartan and captopril are frequently used in the treatment of patients with Type 2 diabetes. These drugs also exert beneficial metabolic effects, causing an improved glucose tolerance in patients, but the precise mechanisms by which this is achieved remain elusive. To this end, we have studied whether these drugs influence insulin secretion in vivo through effects on islet blood perfusion. Captopril (3 mg/kg of body weight), irbesartan (3 mg/kg of body weight) and pravastatin (0.5 mg/kg of body weight) were injected intravenously into anaesthetized female Wistar rats. Blood flow rates were determined by a microsphere technique. Blood glucose concentrations were measured with test reagent strips and serum insulin concentrations were measured by ELISA. Pancreatic blood flow was markedly increased by pravastatin (P<0.001), captopril (P<0.05) and irbesartan (P<0.01). Pancreatic islet blood flow was significantly and preferentially enhanced after the administration of captopril (P<0.01), irbesartan (P<0.01) and pravastatin (P<0.001). Kidney blood flow was enhanced significantly by pravastatin (P<0.01), irbesartan (P<0.05) and captopril (P<0.01). Captopril and pravastatin also enhanced late-phase insulin secretion and positively influenced glycaemia in intraperitoneal glucose tolerance tests. In conclusion, the present study suggests that a local pancreatic renin-angiotensin system and pravastatin treatment may be selectively controlling pancreatic islet blood flow, augmenting insulin secretion and thereby improving glucose tolerance. Our findings indicate significant gender-related differences in the vascular response to these agents. Since statins and renin-angiotensin system inhibitors are frequently used by diabetic patients, the antidiabetic actions of these drugs reported previously might occur, in part, through the beneficial direct islet effects shown in the present study.
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PMID:Vasoactive drugs enhance pancreatic islet blood flow, augment insulin secretion and improve glucose tolerance in female rats. 1702 May 39

Diabetes mellitus induces a decrease in sodium potassium-adenosine triphosphatase (Na+/K(+)-ATPase) activity in several tissues in the rat and red blood cells (RBC) and nervous tissue in human patients. This decrease in Na+/K(+)-ATPase activity is thought to play a role in the development of long-term complications of the disease. Angiotensin enzyme inhibitors (ACEi) and angiotensin-II receptor antagonists (ARBs) reduce proteinuria and retard the progression of renal failure in patients with IDDM and diabetic rats. We investigated the effects of captopril and losartan, which are used in the treatment of diabetic nephropathy, on Na+/K(+)-ATPase activity. Captopril had an inhibitory effect on red cell plasma membrane Na+/K+ ATPase activity, but losartan did not. Our study draws attention to the inhibitory effect of captopril on Na+/K+ ATPase activity. Micro and macro vascular complications are preceeding mortality and morbidity causes in diabetes mellitus. There is a strong relationship between the decrease in Na+/K+ ATPase activity and hypertension. The non-sulphydryl containing ACEi and ARBs must be the choice of treatment in hypertensive diabetic patients and diabetic nephropathy.
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PMID:The effects of captopril and losartan on erythrocyte membrane Na+/K(+)-ATPase activity in experimental diabetes mellitus. 1751 48

Elevated levels of circulating prorenin, the precursor of renin, have been reported to precede the appearance of microvascular complications in diabetes mellitus. Although several studies using animal models have attempted to address the link between elevated prorenin and the tissue remodeling and damage associated with both hypertension and diabetes mellitus, the results have been contradictory, and the mechanism whereby prorenin might contribute to these pathologies remains a subject of debate. To directly test the role of prorenin in these pathologies, we generated transgenic mice with selective increases (13- to 66-fold) in circulating native or active site-mutated prorenin. Systolic blood pressure was either unchanged or increased (+25 mm Hg) in native prorenin-expressing mice, whereas the mice expressing active site-mutated prorenin showed no significant differences in systolic blood pressure compared with control animals. There was no increase in cardiac fibrosis or renal glomerular sclerosis in any of the transgenic animals tested, even at an advanced age (18 months). Captopril (an angiotensin-converting enzyme inhibitor) rapidly normalized blood pressure of hyperproreninemic mice, whereas infusion of the putative antagonist of the prorenin receptor (handle region peptide) had no effect. These results suggest that the primary consequence of chronic elevations in circulating prorenin is an increase in blood pressure and do not support a role for prorenin as the primary causative agent in cardiac fibrosis or renal glomerular injury. The lack of effect seen with active site-mutated prorenin and the efficacy of angiotensin-converting enzyme inhibition are also consistent with prorenin acting through the generation of angiotensin II to raise blood pressure.
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PMID:Chronic increases in circulating prorenin are not associated with renal or cardiac pathologies. 1947 Aug 67

The renin-angiotensin system (RAS) is functional within adipose tissue and angiotensin II, the active component of RAS, has been implicated in adipose tissue hypertrophy and insulin resistance. In this study, captopril, an angiotensin converting enzyme (ACE) inhibitor that prevents angiotensin II formation, was used to study the development of diet-induced obesity and insulin resistance in obesity prone C57BL/6J mice. The mice were fed a high fat diet (w/w 21% fat) and allowed access to either water or water with captopril added (0.2 mg/ml). Body weight was recorded weekly and water and food intake daily. Glucose tolerance was determined after 11-12 weeks. On completion of the study (after 16 weeks of treatment), the mice were killed and kidney, liver, epididymal fat and extensor digitorum longus muscle (EDL) were weighed. Blood samples were collected and plasma analysed for metabolites and hormones. Captopril treatment decreased body weight in the first 2 weeks of treatment. Food intake of captopril-treated mice was similar to control mice prior to weight loss and was decreased after weight loss. Glucose tolerance was improved in captopril-treated mice. Captopril-treated mice had less epididymal fat than control mice. Relative to body weight, captopril-treated mice had increased EDL weight. Relative to control mice, mice administered captopril had a higher plasma concentration of adiponectin and lower concentrations of leptin and non-esterified fatty acids (NEFA). The results indicate that captopril both induced weight loss and improved insulin sensitivity. Thus, captopril may eventually be used for the treatment of obesity and Type 2 diabetes.
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PMID:Angiotensin converting enzyme inhibition lowers body weight and improves glucose tolerance in C57BL/6J mice maintained on a high fat diet. 1946 40


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