Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The renin-angiotensin system (RAS) is compartmented between circulating blood and tissue pericellular space. Whereas renin and its substrate diffuse easily from one compartment to another, the angiotensin peptides act in the compartment where there are generated: blood or pericellular space. Renin is trapped in tissues by low and high affinity receptors. In the target cells, angiotensin II/AT1 receptor interaction generates different signals including an immediate functional calcium-dependent response, secondary hypertrophy and a late proinflammatory and procoagulant response. These late pathological effects are mediated by NADPH oxydase-generated free oxygen radicals and NFkappaB activation. In vivo, the tissue binding of renin and the induction of converting enzyme are the main determinants of the involvement of the RAS in vascular remodeling. The target cells of interstitial angiotensin II are mainly the vascular smooth muscle cells and fibroblasts, whereas the endothelial cells and circulating leukocytes are the main targets of circulating angiotensin II. In vivo, angiotensin II participates in the vascular wall hypertrophy associated with hypertension. In diabetes, as in other localized fibrotic cardiovascular diseases, the tissue effects of angiotensin II are mainly dependent on its ability to induce TGF-beta expression. In experimental atherosclerosis, angiotensin II infusion induces aneurysm formation mediated by activation of circulating leucocytes. In these models, the administration of angiotensin II antagonists has beneficial effects on pathological remodeling. Such beneficial effects of angiotensin II antagonists in localized pathological remodeling have not yet been demonstrated in humans.
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PMID:[Renin-angiotensin system and vascular remodelling]. 1512 12

The angiotensin II receptor blockers (ARBs), are highly selective for the AT1 subtype and will block the effects of angiotensin II on peripheral vessels. Several short- and long-term studies have shown these agents to be safe and effective antihypertensive drugs. Since monotherapy of hypertension may be ineffective in lowering the blood pressure to goal, the use of an ARB, especially in combination with a diuretic or another medication, is frequently necessary to bring the blood pressure <140/90 mm Hg (<130/80 mm Hg among people with diabetes mellitus or chronic renal failure), according to JNC 7 guidelines. Besides hypertension, the ARBs have been shown to reduce left ventricular hypertrophy in hypertensive patients. Other benefits of these medications, as well as the angiotensin I converting enzyme inhibitors (ACEIs), include a decrease in cardiovascular morbidity and mortality in patients with heart failure, or hypertensive diabetic nephropathy with proteinuria. Some of the beneficial effects noted with the ACEIs and ARBs (congestive heart failure, left ventricular hypertrophy), have also been demonstrated with the use of b blockers alone and in combination with a diuretic. These drugs, i.e., b blockers, ARBs, and ACEIs, seem to exert their beneficial action through the blockade of the renin-angiotensin-aldosterone system. The role of this system in cardiovascular remodeling and its blockade will be discussed in this review, which will specifically summarize data with the ARB, valsartan.
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PMID:Clinical experience with angiotensin receptor blockers with particular reference to valsartan. 1530 83

Previous studies have shown that the renin-angiotensin system (RAS) is activated in diabetes and this may contribute to the subcellular remodelling and heart dysfunction in this disease. Therefore, we examined the effects of RAS blockade by enalapril, an angiotensin-converting enzyme inhibitor, and losartan, an angiotensin receptor AT1 antagonist, on cardiac function, myofibrillar and myosin ATPase activity as well as myosin heavy chain (MHC) isozyme expression in diabetic hearts. Diabetes was induced in rats by a single injection of streptozotocin (65 mg/kg; i.v.) and these animals were treated with and without enalapril (10 mg/kg/day; oral) or losartan (20 mg/kg/day; oral) for 8 weeks. Enalapril or losartan prevented the depressions in left ventricular rate of pressure development, rate of pressure decay and ventricular weight seen in diabetic animals. Both drugs also attenuated the decrease in myofibrillar Ca2+-ATPase, Mg2+-ATPase and myosin ATPase activity seen in diabetic rats. The diabetes-induced increase in beta-MHC content and gene expression as well as the decrease in alpha-MHC content and mRNA levels were also prevented by enalapril and losartan. These results suggest the occurrence of myofibrillar remodelling in diabetic cardiomyopathy and provide evidence that the beneficial effects of RAS blockade in diabetes may be associated with attenuation of myofibrillar remodelling in the heart.
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PMID:Renin-angiotensin blockade attenuates cardiac myofibrillar remodelling in chronic diabetes. 1536 13

Hyperhomocysteinemia is associated with an enhanced risk for cardiovascular disease. Patients with peripheral arterial disease (PAD) show an increased prevalence of hyperhomocysteinemia. A decreased biological activity of nitric oxide (NO) may contribute to homocysteine-associated endothelial dysfunction. This study was designed to investigate whether elevated levels of the endogenous NO synthase inhibitor asymmetric dimethylarginine (ADMA) are involved in endothelial dysfunction in patients with chronic hyperhomocysteinemia and PAD. A total of 76 patients (58 males and 18 females; mean age 65.2 +/- 2.0 years) with PAD were included in the analysis and characterized according to demographic variables and cardiovascular risk factors. Flow-dependent vasodilation (FDD) was determined by high-resolution ultrasound in the radial artery. Total plasma homocysteine (plasma tHcy) and ADMA levels were measured by HPLC. Urinary nitrate was quantified using gas chromatography-mass spectrometry. Patients with plasma tHcy in the highest tertile (n = 27; i.e. > 10.6 micromol/l) had a mean plasma level of 14.4 +/- 1.21 mol/l compared with 9.9 +/- 0.1 micromol/l in those patients in the middle tertile (n = 22; p < 0.05) and 9.4 +/- 0.1 micromol/l in those in the lowest tertile (n = 27; i.e. <9.6 micromol/l; p < 0.05). The hyperhomocysteinemic individuals (highest tertile) had a significantly decreased FDD compared with healthy age-matched controls (n = 15) (7.6 +/- 1.0 vs 13.0 +/- 0.4%; p < 0.05), higher plasma ADMA concentrations (4.0 +/- 0.3 vs 2.6 +/- 0.3 micromol/l; p < 0.05), and a lower urinary nitrate excretion rate (89.5 +/- 13.4 vs 131.3 +/- 17.9 micromol/mmol creatinine; p < 0.05) compared with patients with plasma tHcy in the lowest tertile. Multivariate regression analysis including plasma tHcy, ADMA, total cholesterol, diabetes mellitus, smoking, and systolic blood pressure revealed ADMA as the only significant factor determining FDD (p < 0.05). In conclusion, we demonstrated a stronger relationship between impaired endothelial function and elevated ADMA levels in comparison with plasma tHcy concentrations in patients with PAD and chronic hyperhomocysteinemia. This may raise the question of whether different therapeutical options that interact indirectly with plasma tHcy, i.e. treatment with ACE inhibitors and AT1-receptor blockers to reduce ADMA plasma concentrations or L-arginine, could be a beneficial tool for treating patients with hyperhomocysteinemia.
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PMID:Endothelial dysfunction in patients with peripheral arterial disease and chronic hyperhomocysteinemia: potential role of ADMA. 1552 98

For each known diabetic at least one new patient is diagnosed when the 75-g OGTT is used for screening. For early diagnosis in high risk groups, the oral glucose tolerance test is indispensable since ca. 30% of the asymptomatic diabetes cases are identified on the basis of a 2-hour postchallenge glucose value of > 11.1 mmol/l. In controlled studies on persons with IGT, every second diabetes case could be prevented through lifestyle modifications beginning in childhood. Three-year studies showed that the incidence of diabetes could be reduced by about one-third with the medications acarbose, metformin and orlistat. The observation that statins, ACE inhibitors and AT1 blockers also contributed to a reduction of new diabetes cases was made in studies on the prevention of coronary heart diseases.
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PMID:[Screening, prevention and early therapy of type 2 diabetics]. 1554 May 35

The renin-angiotensin system (RAS) is compartmented between the circulating blood and pericellular spaces. Whereas renin and its substrate diffuse easily from one compartment to another, angiotensin peptides act in the compartment where there are generated. Renin is trapped in tissues by low- and high-affinity receptors. In target cells, angiotensin II/AT1 receptor interaction generates various signals, including an immediate functional calcium-dependent response, secondary hypertrophy, and a late proinflammatory and procoagulant response. These late pathological effects are mediated by NADPH oxidase-generated oxygen free radicals and NF-k-B activation. In vivo, renin tissue binding and converting-enzyme induction are the main determinants of RAS involvement in vascular remodeling. The main target cells of interstitial angiotensin II are vascular smooth muscle cells and fibroblasts, whereas endothelial cells and circulating leukocytes are the main targets of circulating angiotensin II. In vivo, angiotensin II participates in the vascular wall hypertrophy associated with hypertension. In diabetes, as in other localized fibrotic cardiovascular diseases, the tissular effects of angiotensin II are mainly dependent on its ability to induce TGF-beta expression. In experimental atherosclerosis, angiotensin II infusion induces aneurysm formation mediated by activation of circulating leucocytes. Angiotensin II antagonist therapy has beneficial effects on pathological remodeling in animal models, but it remains to be determined whether this is also the case in humans.
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PMID:[Tissue consequence of renin-angiotensin system activation]. 1558 80

Irbesartan (Aprovel) belongs into the new group drugs for the cardiovascular system which exert an antagonistic effect at the level of angiotensin II, but experimental pilot studies as well as clinical studies draw also attention to the possible therapeutic potential of AT1 receptor blockers in the treatment of chronic heart failure. Irbesartan has a marked antihypertensive effect as is apparent from a recent clinical study in 139 patients with mild and moderate hypertension--implemented in the Czech Republic. Twelve-week treatment with Irbesartan led to a marked drop of the systolic and diastolic blood pressure (159.2 +/- 14 vs. 137 +/- 13 mmHg/99.2 +/- 7 vs. 85.3 +/- 7 mmHg, p < 0.01). A very favourable therapeutic effect was recorded in this investigation also in 24-hour monitoring of the blood pressure. The use of irbesartan in patients with arterial hypertension has according to other studies also a favourable effect on organ complications of hypertension and diabetes (regression of left ventricular hypertrophy, reduction of albuminuria). Irbesartan may prove due to its favourable effect a suitable alternative in conditions associated with intolerance of ACE-inhibitors in patients with moderate and severe forms of arterial hypertension, in chronic heart failure and in diabetic nephropathy.
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PMID:[Irbesartan in the treatment of arterial hypertension]. 1564 39

Most individuals with arterial hypertension or congestive heart failure are insulin-resistant and at a higher risk of developing type 2 diabetes (T2DM). The inhibition of the renin-angiotensin system (RAS), using an angiotensin converting enzyme inhibitor (ACEI) or a selective angiotensin receptor AT1 blocker (ARB), may exert favourable metabolic effects capable of preventing T2DM in high risk individuals. We performed a meta-analysis of randomised clinical trials (RCTs) assessing the effects of RAS inhibition on the incidence of new cases of T2DM in patients with arterial hypertension or congestive heart failure. Ten RCTs with cardiovascular prognosis as primary endpoints analysed the incidence of T2DM as secondary endpoints or as post-hoc analysis after a mean follow-up of 1 to 6 years: five with an ACEI and five with an ARB, compared with a placebo (n=4) or a reference drug (beta-blocker or diuretic: n=5; amlodipine: n=2). Eight RCTs concerned hypertensive patients: STOP Hypertension-2 (lisinopril or enalapril vs beta-blocker or diuretic), CAPPP (captopril vs thiazide or beta-blocker), HOPE (ramipril vs placebo), ALLHAT (lisinopril vs chlorthalidone and lisinopril vs amlodipine), LIFE (losartan vs atenolol), SCOPE (candesartan vs placebo), ALPINE (candesartan vs placebo) and VALUE (valsartan vs amlodipine). Two RCTs concerned patients with congestive heart failure: SOLVD (enalapril vs placebo) and CHARM-overall programme (candesartan vs placebo). Overall, 2 675 new cases of T2DM (7.40%) were observed in the group of 36 167 patients receiving a treatment with ACEI or ARA as compared with 3 842 events (9.63%) in the group of 39 902 control patients. A mean weighed relative risk reduction of new T2DM of 22% (95% CI: 18, 26; p<0.00001) was observed after RAS inhibition. The beneficial effect was similar with ACEIs and with ARBs as well as in patients with hypertension and in those with heart failure, and was also present whatever the comparator (placebo or beta-blockers/diuretics or amlodipine). The number needed-to-treat to avoid one new case of T2DM averaged 45 patients over 4-5 years. In conclusion, RAS inhibition consistently and significantly reduces the incidence of T2DM in individuals with arterial hypertension or with congestive heart failure. Considering the pandemic of T2DM, such pharmacological approach deserves further attention among the strategies aiming at preventing T2DM.
Diabetes Metab 2004 Dec
PMID:Renin-angiotensin system inhibition prevents type 2 diabetes mellitus. Part 1. A meta-analysis of randomised clinical trials. 1567 18

The inhibition of the renin-angiotensin system (RAS) with either angiotensin converting enzyme inhibitors (ACEIs) or AT1 angiotensin receptor blockers (ARBs) consistently and significantly reduces the incidence of type 2 diabetes in patients with hypertension or congestive heart failure. The mechanisms underlying this protective effect appear to be complex and may involve an improvement of both insulin sensitivity and insulin secretion. These two effects may result, at least in part, from the well known effects of these pharmacological agents on the vascular system on the one hand, on the ionic balance on the other hand. Indeed, the vasodilation induced by ACEIs or ARBs could improve the blood circulation in skeletal muscles, thus favouring peripheral insulin action, but also in the pancreas, thus promoting insulin secretion. Preserving cellular potassium and magnesium pools by blocking the aldosterone effects could also improve both cellular insulin action and insulin secretion. However, besides these classical effects, new mechanisms have been recently suggested. A direct effect of the inhibition of angiotensin and/or of the enhancement of bradykinin on various steps of the insulin cascade signalling has been described as well an increase in GLUT4 glucose transporters after RAS inhibition. Furthermore, it has been demonstrated that angiotensin II inhibits adipogenic differentiation of human adipocytes via A1 receptors and, therefore, it has been hypothesised that RAS blockade may prevent diabetes by promoting the recruitment and differentiation of adipocytes. Finally, some lipophilic ARBs appear to induce PPAR-gamma activity in the adipose tissue. Hence, the protection against type 2 diabetes observed after RAS inhibition may be partially linked to a thiazolidinedione-like effect. In conclusion, numerous physiological and biochemical mechanisms could explain the protective effect of RAS inhibition against the development of type 2 diabetes in individuals with arterial hypertension or congestive heart failure. What might be the main mechanism in the overall protection effect of ACEIs or ARBs remains an open question.
Diabetes Metab 2004 Dec
PMID:Renin-angiotensin system inhibition prevents type 2 diabetes mellitus. Part 2. Overview of physiological and biochemical mechanisms. 1567 19

Hyperglycemia was reported to enhance angiotensin (Ang) II generation in rat cardiomyocytes, and Ang II inhibition reduces cardiovascular morbidity and mortality in diabetic patients. In diabetic patients, the enhanced activation of intracellular pathways related with myocyte hypertrophy and gene expression might enhance the progression of cardiac damage. Therefore, we investigated the effects of glucose on Ang II-mediated activation of Janus-activated kinase (JAK)-2, a tyrosine kinase related with myocyte hypertrophy and cytokine and fibrogenetic growth factor overexpression, in ventricular myocytes isolated from nonfailing human hearts (n = 5) and failing human hearts (n = 8). In nonfailing myocytes, JAK2 phosphorylation was enhanced by Ang II only in the presence of high glucose (25 mmol/l) via Ang II type I (AT1) receptors (+79% vs. normal glucose, P < 0.05). JAK2 activation was prevented by inhibitors of reactive oxygen species (ROS) generation (diphenyleneiodonium [DPI], tiron, and apocynin). In myocytes isolated from failing hearts, JAK2 phosphorylation was enhanced by high glucose alone (+107%, P < 0.05). High glucose-induced JAK2 activation was blunted by both ACE inhibition (100 nmol/l ramipril) and AT1 antagonism (1 mumol/l valsartan), thus revealing that the effects are mediated by autocrine Ang II production. Inhibition of ROS generation also prevented high glucose-induced JAK2 phosphorylation. In conclusion, in human nonfailing myocytes, high glucose allows Ang II to activate JAK2 signaling, whereas in failing myocytes, hyperglycemia alone is able to induce Ang II generation, which in turn activates JAK2 via enhanced oxidative stress.
Diabetes 2005 Feb
PMID:Hyperglycemia activates JAK2 signaling pathway in human failing myocytes via angiotensin II-mediated oxidative stress. 1567 97


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