UMLS:C0011860 - FACTA Search

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Query: UMLS:C0011860 (type 2 diabetes)
57,723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reduced insulin sensitivity is characteristic of various pathological conditions such as type 2 diabetes mellitus and hypertension. Angiotensin II, acting through its angiotensin type 1 receptor, inhibits the actions of insulin in the vasculature which may lead to deleterious effects such as vascular inflammation, remodeling, endothelial dysfunction, and insulin resistance. In contrast, insulin normally exerts vasodilatory, antiinflammatory, and prosurvival actions. To explore the impact of angiotensin II on insulin signaling, NADPH oxidase-derived reactive oxygen species formation, vascular inflammation, apoptosis, and remodeling, we used transgenic TG(mRen2)27 (Ren2) rats, which harbor the mouse renin transgene and exhibits elevated tissue angiotensin II levels. Compared with Sprague-Dawley controls, Ren2 aortas exhibited greater NADPH oxidase activity, reactive oxygen species levels, C-reactive protein, tumor necrosis factor-alpha expression, apoptosis, and wall thickness, which were significantly attenuated by in vivo treatment with angiotensin type 1 receptor blockade (valsartan) or the superoxide dismutase/catalase mimetic (tempol). There was substantially diminished Akt and endothelial NO synthase activation in Ren2 aortas in response to in vivo insulin stimulation, and this was significantly improved by in vivo treatment with valsartan or tempol. In vivo treatment with valsartan, but not tempol, significantly reduced blood pressure in Ren2 rats. Further, there was reduced insulin induced Akt activation and increased tumor necrosis factor-alpha levels in vascular smooth muscle cells from Ren2 and Sprague-Dawley rats treated with angiotensin II, abnormalities that were abrogated by angiotensin type 1 receptor blockade with valsartan or antioxidant N-acetylcysteine. Collectively, these data suggest that increased angiotensin type 1 receptor/NADPH oxidase activation/reactive oxygen species contribute to vascular insulin resistance, endothelial dysfunction, apoptosis, and inflammation.
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PMID:NADPH oxidase contributes to vascular inflammation, insulin resistance, and remodeling in the transgenic (mRen2) rat. 1753 99

Angiotensin II (Ang II) is able to induce free radical generation in neutrophils, which is more elevated in neutrophils of patients with hypercholesterolemia (HC). In addition, the signal processing through angiotensin I (Ang I) receptors is altered. In present study, we compared the Ang II-triggered free radical generation of neutrophils obtained from patients with relatively isolated forms of metabolic syndrome (MS) with membrane-bound cholesterol content and membrane fluidity. We determined the enhancement of Ang II-induced superoxide anion and leukotriene C(4) (LTC(4)) generation, membrane fluidity and cell-bound cholesterol content of neutrophils obtained from 12 control subjects, 11 patients with obesity (Ob), 10 patients with type 2 diabetes mellitus (t2-DM) and 12 patients with HC. The alteration of signal processing was studied after preincubation with different inhibiting drugs. Superoxide anion, LTC(4) production and membrane rigidity were increased in the following order: control < Ob < t2-DM < HC. Both Ang II-induced superoxide anion and LTC(4) generation were decreased in control cells by pertussis toxin and fluvastatin (Flu), whereas in each patient group, mepacrin, verapamil and Flu were effective, suggesting alterations in signal pathways, which may be attributed to isoprenylation. The enhancement of superoxide anion and LTC(4) generation correlated significantly with membrane rigidity, independently from the experimental groups and membrane-bound cholesterol content. Membrane rigidity of neutrophils, obtained from patients with MS, plays a role in Ang II-induced free radical generation independent of intracellular cholesterol homeostasis.
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PMID:The association between angiotensin II-induced free radical generation and membrane fluidity in neutrophils of patients with metabolic syndrome. 1754 12

The reduced capacity of insulin to stimulate glucose transport into skeletal muscle, termed insulin resistance, is a primary defect leading to the development of prediabetes and overt type 2 diabetes. Although the etiology of this skeletal muscle insulin resistance is multifactorial, there is accumulating evidence that one contributor is overactivity of the renin-angiotensin system (RAS). Angiotensin II (ANG II) produced from this system can act on ANG II type 1 receptors both in the vascular endothelium and in myocytes, with an enhancement of the intracellular production of reactive oxygen species (ROS). Evidence from animal model and cultured skeletal muscle cell line studies indicates ANG II can induce insulin resistance. Chronic ANG II infusion into an insulin-sensitive rat produces a markedly insulin-resistant state that is associated with a negative impact of ROS on the skeletal muscle glucose transport system. ANG II treatment of L6 myocytes causes impaired insulin receptor substrate (IRS)-1-dependent insulin signaling that is accompanied by augmentation of NADPH oxidase-mediated ROS production. Further critical evidence has been obtained from the TG(mREN2)27 rat, a model of RAS overactivity and insulin resistance. The TG(mREN2)27 rat displays whole body and skeletal muscle insulin resistance that is associated with local oxidative stress and a significant reduction in the functionality of the insulin receptor (IR)/IRS-1-dependent insulin signaling. Treatment with a selective ANG II type 1 receptor antagonist leads to improvements in whole body insulin sensitivity, enhanced insulin-stimulated glucose transport in muscle, and reduced local oxidative stress. In addition, exercise training of TG(mREN2)27 rats enhances whole body and skeletal muscle insulin action. However, these metabolic improvements elicited by antagonism of ANG II action or exercise training are independent of upregulation of IR/IRS-1-dependent signaling. Collectively, these findings support targeting the RAS in the design of interventions to improve metabolic and cardiovascular function in conditions of insulin resistance associated with prediabetes and type 2 diabetes.
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PMID:Improvement of insulin sensitivity by antagonism of the renin-angiotensin system. 1758 38

Endothelial dysfunction is the initial pathophysiological step in a progression of vascular damage that leads to overt cardiovascular and chronic kidney disease. Angiotensin II, the primary agent of the renin-angiotensin system (RAS), has a central role in endothelial dysfunction. Therefore, RAS blockade with an angiotensin receptor blocker (ARB) and/or angiotensin-converting enzyme (ACE) inhibitor provides a rational approach to reverse endothelial dysfunction, reduce microalbuminuria, and, thus, improves cardiovascular and renal prognosis. ARBs and ACE inhibitors act at different points in the RAS pathway and recent evidence suggests that there are differences regarding their effects on endothelial dysfunction. In addition to blood pressure lowering, studies have shown that ARBs reduce target-organ damage, including improvements in endothelial dysfunction, arterial stiffness, the progression of renal dysfunction in patients with type 2 diabetes, proteinuria, and left ventricular hypertrophy. The ONgoing Telmisartan Alone in combination with Ramipril Global Endpoint Trial (ONTARGET) Programme is expected to provide the ultimate evidence of whether improved endothelial function translates into reduced cardiovascular and renal events in high-risk patients, and to assess possible differential outcomes with telmisartan, the ACE inhibitor ramipril, or a combination of both (dual RAS blockade). Completion of ONTARGET is expected in 2008.
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PMID:Cardiovascular risk reduction by reversing endothelial dysfunction: ARBs, ACE inhibitors, or both? Expectations from the ONTARGET Trial Programme. 1758 70

Diabetic nephropathy is the most important cause of ESRD. The aim of this study was to develop a risk score from risk predictors for ESRD, with and without death, in the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study and to compare ability of the ESRD risk score and its components to predict ESRD. The risk score was developed from coefficients of independent risk factors from multivariate analysis of baseline variables and equals (1.96 x log [urinary albumin:creatinine ratio]) - (0.78 serum albumin [g/dl]) + (1.28 x serum creatinine [mg/dl]) - (0.11 x hemoglobin [g/dl]). It was robust with respect to severity of nephropathy, gender, race, and treatment group. The risk score for ESRD or death was comparable. The four risk predictors for progression of kidney disease were independent of therapy. For combined treatment groups, the hazard ratio between the fourth and first quartiles of the ESRD risk score was 49.0, as compared with the corresponding hazard ratios for each component: 14.7 for urinary albumin:creatinine ratio, 9.2 for serum creatinine, 5.5 for hemoglobin, and 10.2 for serum albumin. The RENAAL risk scores for ESRD with or without death emphasize the importance of identification of level of albuminuria, serum albumin, serum creatinine, and hemoglobin to predict development of ESRD in patients with type 2 diabetes and nephropathy. Although albuminuria is a strong risk factor for ESRD, the contribution of serum albumin, serum creatinine, and hemoglobin level further enhances prediction of ESRD. Future trials with a similar patient population and outcomes measures should consider adjusting analyses for baseline risk factors.
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PMID:Risk scores for predicting outcomes in patients with type 2 diabetes and nephropathy: the RENAAL study. 1769 65

Renal pathology and dyslipidemia commonly coexist. Treatments that lower albuminuria/proteinuria may lower lipids, but it is not known whether lipid lowering independent of lessening albuminuria/proteinuria slows progression of kidney disease. We examined the association between LDL cholesterol levels and treatment with losartan on end-stage renal disease (ESRD). Lipid levels and albuminuria measurements were obtained at baseline and at year 1 in a post hoc analysis from the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study, which compared the effects of losartan- versus placebo-based antihypertensive therapy in patients with type 2 diabetes and nephropathy. LDL cholesterol lowering was associated with a lower risk of ESRD; however, this seemed to be largely an association with the reduction in albuminuria.
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PMID:Effect of LDL cholesterol and treatment with losartan on end-stage renal disease in the RENAAL study. 1807 Sep 95

Reduced insulin sensitivity is a key factor in the pathogenesis of type 2 diabetes and hypertension. Skeletal muscle insulin resistance is particularly important for its major role in insulin-mediated glucose disposal. Angiotensin II (ANG II) is integral in regulating blood pressure and plays a role in the pathogenesis of hypertension. In addition, we have documented that ANG II-induced skeletal muscle insulin resistance is associated with generation of reactive oxygen species (ROS). However, the linkage between ROS and insulin resistance in skeletal muscle remains unclear. To explore potential mechanisms, we employed the transgenic TG(mRen2)27 (Ren-2) hypertensive rat, which harbors the mouse renin transgene and exhibits elevated tissue ANG II levels, and skeletal muscle cell culture. Compared with Sprague-Dawley normotensive control rats, Ren-2 skeletal muscle exhibited significantly increased oxidative stress, NF-kappaB activation, and TNF-alpha expression, which were attenuated by in vivo treatment with an angiotensin type 1 receptor blocker (valsartan) or SOD/catalase mimetic (tempol). Moreover, ANG II treatment of L6 myotubes induced NF-kappaB activation and TNF-alpha production and decreased insulin-stimulated Akt activation and GLUT-4 glucose transporter translocation to plasma membranes. These effects were markedly diminished by treatment of myotubes with valsartan, the antioxidant N-acetylcysteine, NADPH oxidase-inhibiting peptide (gp91 ds-tat), or NF-kappaB inhibitor (MG-132). Similarly, NF-kappaB p65 small interfering RNA reduced NF-kappaB p65 subunit expression and nuclear translocation and TNF-alpha production but improved insulin-stimulated phosphorylation (Ser(473)) of Akt and translocation of GLUT-4. These findings suggest that NF-kappaB plays an important role in ANG II/ROS-induced skeletal muscle insulin resistance.
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PMID:Angiotensin II-induced skeletal muscle insulin resistance mediated by NF-kappaB activation via NADPH oxidase. 1807 21

Moderate elevations in blood pressure translate to significant increases in cardiovascular and cerebro vascular risk. Beneficially, this relationship allows small decreases in blood pressure to be associated with risk reduction. Both the renin-angiotensin system and the sympathetic nervous system are involved in hypertension, hence targeting these systems is likely to be of benefit in the treatment of hypertension. Angiotensin II type 1 receptor blockers (ARBs) are used for controlling blood pressure and treating heart failure in a broad range of patients, including those with diabetes and the elderly. Not only have ARBs shown good efficacy and tolerability, they also appear to have a protective effect that goes beyond that expected from the reduction of blood pressure. The ARB eprosartan is a nonbiphenyl nontetrazole angiotensin II type 1 receptor (AT1) antagonist, which acts to decrease total peripheral resistance. Eprosartan acts at vascular AT1 receptors (postsynaptically) and at presynaptic AT1 receptors, where it inhibits noradrenaline release. In clinical studies, eprosartan has been shown to significantly reduce cardiovascular and cerebrovascular events, whilst avoiding the persistent cough that commonly occurs with the use of angiotensin-converting enzyme inhibitors. Eprosartan can also be differentiated from other ARBs due to its noradrenergic effects, which other ARBs used at therapeutic doses do not possess. Eprosartan, therefore, represents a useful therapeutic option in the management of patients with hypertension, including those with a history of stroke or with co-morbid type 2 diabetes mellitus.
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PMID:Introduction: The pharmacological profile of eprosartan--implications for cerebrovascular and cardiovascular risk reduction. 1809 7

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers can decrease hemoglobin, causing anemia and this may be an independent risk factor for chronic kidney disease progression. We studied the relationship between a decline in hemoglobin and outcome in 1513 patients with type 2 diabetes and kidney disease by a post hoc analysis of the RENAAL Study (Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan) with an average follow-up of 3.4 years. The relationship between baseline and year-1 hemoglobin and treatment on end-stage renal disease (ESRD) and ESRD or death was evaluated using multivariate Cox models (covariates: baseline hemoglobin, proteinuria, serum albumin, serum creatinine, and year-1 hemoglobin). Compared with placebo, losartan treatment was associated with a significant decrease of hemoglobin, with the largest between-group difference at 1 year. After adjustment, there were significant relative risk reductions for losartan compared with placebo for ESRD and for ESRD or death regardless of the baseline hemoglobin even in those patients with a baseline hemoglobin below 120 g l(-1). Hence, the renoprotective properties of losartan were maintained despite a significant lowering of the hemoglobin concentration.
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PMID:The effect of losartan on hemoglobin concentration and renal outcome in diabetic nephropathy of type 2 diabetes. 1809 75

Losartan treatment reduced renal outcomes in proteinuric patients with type 2 diabetes in the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study. It is unknown whether an insertion (I)/deletion (D) polymorphism in the angiotensin I-converting enzyme (ACE) gene predicts renal outcomes and death and influences the effect of losartan in these patients. Pharmacogenetic analyses were performed comparing losartan with placebo administered with conventional blood pressure-lowering therapy in 1435 (95%) of the 1513 RENAAL study patients. The primary endpoint was the composite of doubling of baseline serum creatinine concentration, end-stage renal disease (ESRD) or death. Cox regression models were stratified on baseline proteinuria and included treatment, geographic region, ACE/ID genotype, and treatment x genotype interaction. Within the placebo group, subjects with the ID or DD genotype were more likely than those with the II genotype to reach the composite endpoint (by 17.5% and 38.1%, respectively, P = 0.029) or its individual components. Within the losartan group, genotype did not correlate with reaching the composite endpoint. Compared with placebo, however, losartan reduced the risk of reaching the composite endpoint by 5.8% (95% confidence interval, -23.3, 28.0), 17.6% (3.8, 29.4), and 27.9% (7.0, 44.1) among those with the II, ID, and DD genotypes, respectively. Similar trends were demonstrated for the individual endpoints. In conclusion, proteinuric type 2 diabetic patients with the D allele of the ACE gene have an unfavorable renal prognosis, which can be mitigated and even improved by losartan.
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PMID:ACE gene polymorphism and losartan treatment in type 2 diabetic patients with nephropathy. 1819 98

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