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)

Vascular upregulation of nitric oxide (NO) is an adaptive response to increased blood pressure that may help in the prevention of end-organ damage. Differences in cardiovascular and renal morbidity and mortality in hypertensive patients may result, at least in part, from individual variations in endothelial function in response to the hemodynamic workload of hypertension. A functional feedback balance exists between both angiotensin (Ang) II and NO under normal conditions. The NO-Ang II imbalance may not explain all the vascular pathophysiology of hypertension, but it certainly appears to be an important component. In hypertension, salt sensitivity, whether primary (ie, certain populations in the United States and Japan) or secondary (ie, aging, type II diabetes), appears to be a marker of increased cardiovascular and renal risk that is often linked to a decreased bioactivity of NO. In diabetes and atherosclerosis, NO-dependent vascular relaxation is impaired and can be restored by decreasing the synthesis and/or blocking the action of Ang II. An understanding of the relations between hypertension, cardiovascular risk factors, end-organ damage, and the NO-Ang II axis leads one to believe that the combination of therapeutic agents capable of reinstating the homeostatic balance of these vasoactive molecules within the vessel wall would be most effective in preventing or arresting end-organ disease.
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PMID:Workshop: hypertension and cardiovascular risk factors: role of the angiotensin II-nitric oxide interaction. 1123 Mar 71

Stimulation of the local renin-angiotensin system and apoptosis characterize the diabetic heart. Because IGF-1 reduces angiotensin (Ang) II and apoptosis, we tested whether streptozotocin-induced diabetic cardiomyopathy was attenuated in IGF-1 transgenic mice (TGM). Diabetes progressively depressed ventricular performance in wild-type mice (WTM) but had no hemodynamic effect on TGM. Myocyte apoptosis measured at 7 and 30 days after the onset of diabetes was twofold higher in WTM than in TGM. Myocyte necrosis was apparent only at 30 days and was more severe in WTM. Diabetic nontransgenic mice lost 24% of their ventricular myocytes and showed a 28% myocyte hypertrophy; both phenomena were prevented by IGF-1. In diabetic WTM, p53 was increased in myocytes, and this activation of p53 was characterized by upregulation of Bax, angiotensinogen, Ang type 1 (AT(1)) receptors, and Ang II. IGF-1 overexpression decreased these biochemical responses. In vivo accumulation of the reactive O(2) product nitrotyrosine and the in vitro formation of H(2)O(2)-(.)OH in myocytes were higher in diabetic WTM than TGM. Apoptosis in vitro was detected in myocytes exhibiting high H(2)O(2)-(.)OH fluorescence, and apoptosis in vivo was linked to the presence of nitrotyrosine. H(2)O(2)-(.)OH generation and myocyte apoptosis in vitro were inhibited by the AT(1) blocker losartan and the O(2) scavenger TIRON: In conclusion, IGF-1 interferes with the development of diabetic myopathy by attenuating p53 function and Ang II production and thus AT(1) activation. This latter event might be responsible for the decrease in oxidative stress and myocyte death by IGF-1.
Diabetes 2001 Jun
PMID:IGF-1 overexpression inhibits the development of diabetic cardiomyopathy and angiotensin II-mediated oxidative stress. 1137 43

Angiotensin II (Ang II) is a vasopressor peptide involved in the pathogenesis of cardiovascular diseases associated with diabetes mellitus. We have previously reported that the 5-lipoxygenase-derived products, particularly the cysteinyl leukotrienes (CysLTs), are involved in Ang II-induced contraction. In this study, we demonstrated that CysLTs contribute to the contraction elicited by Ang II in isolated aortas from streptozotocin-induced diabetic (SS) rats but not from insulin-treated diabetic rats, fructose-fed rats, or control rats. In an organ bath, pretreatment with the 5-lipoxygenase inhibitor (AA861, 10 micromol/L) reduced by 37.6+/-8.2% and 30.1+/-10.9% the Ang II-induced contractions in intact and endothelium-denuded aortic rings, respectively, from SS rats. In contrast, the CysLT(1) receptor antagonist (MK571, 1 micromol/L) or the dual CysLT(1)/CysLT(2) receptor antagonist (BAY-u9773, 0.1 micromol/L) did not affect Ang II-induced contraction. In addition, Ang II induced a 6.2+/-1.5-fold increase in CysLT release through the stimulation of the Ang II type 1 receptor. Furthermore, the urinary excretion of leukotriene E(4) was increased in SS rats (leukotriene E(4), 13.7+/-2.9 ng/24 h [SS rats, n=10] versus 1.5+/-0.5 ng/24 h [control rats, n=6]; P<0.0004). These data suggest the activation of the 5-lipoxygenase pathway in SS rats and the involvement of 5-lipoxygenase-derived products, particularly the CysLTs, in Ang II-induced contraction in aortas from SS rats through stimulation of CysLT receptors different from the well-characterized CysLT(1) or CysLT(2) receptor.
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PMID:Cysteinyl leukotrienes modulate angiotensin II constrictor effects on aortas from streptozotocin-induced diabetic rats. 1170 61

Clinical and animal studies have shown that treatment with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II (Ang II) receptor antagonists slows the progression of nephropathy in diabetes, indicating that Ang II plays an important role in its development. We have reported previously that insulin inhibits the stimulatory effect of high glucose levels on angiotensinogen (ANG) gene expression in rat immortalized renal proximal tubular cells (IRPTCs) via the mitogen-activated protein kinase (p44/42 MAPK) signal transduction pathway. We hypothesize that the suppressive action of insulin on ANG gene expression might be attenuated in renal proximal tubular cells (RPTCs) of rats with established diabetes. Two groups of male adult Wistar rats were studied: controls and streptozotocin (STZ)-induced diabetic rats at 2, 4, 8 and 12 weeks post-STZ administration. Kidney proximal tubules were isolated and cultured in either normal glucose (i.e. 5 mM) or high glucose (i.e. 25 mM) medium to determine the inhibitory effect of insulin on ANG gene expression. Immunoreactive rat ANG (IR-rANG) in culture media and cellular ANG mRNA were measured by a specific radioimmunoassay and reverse transcription-polymerase chain reaction assay respectively. Activation of the p44/42 MAPK signal transduction pathway in rat RPTCs was evaluated by p44/42 MAPK phosphorylation employing a PhosphoPlus p44/42 MAPK antibody kit. Insulin (10(-7) M) inhibited the stimulatory effect of high glucose levels on IR-rANG secretion and ANG gene expression and increased p44/42 MAPK phosphorylation in normal rat RPTCs. In contrast, it failed to affect these parameters in diabetic rat RPTCs. In conclusion, our studies demonstrate that hyperglycaemia induces insulin resistance on ANG gene expression in diabetic rat RPTCs by altering the MAPK signal transduction pathway.
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PMID:Hyperglycemia induces insulin resistance on angiotensinogen gene expression in diabetic rat kidney proximal tubular cells. 1183 51

In the United States, approximately 16 million people have diabetes; 90-95% have type 2 diabetes. They are at increased risk of developing hypertension and cardiovascular disease (CVD). The benefits of treating hypertension in diabetic patients and the potential to delay complications and reduce mortality have been demonstrated in clinical trials. Increasing evidence shows that angiotensin-converting enzyme (ACE) inhibitors and angiotensin II (Ang II) receptor blockers (ARBs) may be equally effective in delaying progressive renal disease in diabetic patients. Large, multicentre trials are ongoing to confirm the efficacy and superior safety profile of ARBs in this population.
Diabetes Obes Metab 2001 Dec
PMID:Treatment of high-risk diabetic patients with angiotensin II receptor blockers. 1190 21

Poor glycaemic control and high blood pressure are two important risk factors for the development of retinopathy and nephropathy in Type 1 diabetes. The renin-angiotensin-aldosterone system (RAAS) may be involved in this process, since treatment with angiotensin-converting enzyme (ACE) inhibitors postpones the development of these complications. We investigated whether plasma renin activity (PRA), plasma angiotensin II (Ang II) and atrial natriuretic peptide (ANP) differed in Type 1 diabetic patients compared with healthy controls. We recruited 80 patients with Type 1 diabetes of more than 10 years' duration and 75 age-matched controls. We found that PRA and Ang II concentrations were significantly lower in patients than in the controls. The levels of ANP, on the other hand, were higher in patients than in controls. PRA correlated negatively to the mean value of HbA(1c) during the previous five years. PRA and Ang II were significantly lower in patients with mean HbA(1c) >8.4% compared with those with mean HbA(1c) <7.2%. In summary, we found patients with Type 1 diabetes to have RAAS suppression and increased ANP levels, suggesting a state of fluid retention.
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PMID:The renin-angiotensin-aldosterone system is suppressed in adults with Type 1 diabetes. 1196 22

Recent studies suggest that angiotensin II (Ang II) plays a role in the adipogenesis of murine preadipocytes. Here, we examined the role of Ang II for the differentiation of primary cultured human preadipocytes. Preadipocytes were isolated from human adipose tissue and stimulated to differentiate. Quantitation of gene expression during adipogenesis was performed for renin-angiotensin system (RAS) genes. The influence of the RAS on adipogenic differentiation was investigated by addition of either angiotensinogen (AGT), Ang II, or angiotensin receptor antagonists to the differentiation medium. We also examined the influence of adipocytes on adipogenesis by co-culture experiments. Expression of the RAS genes AGT, renin, angiotensin-converting enzyme, and Ang II type 1 receptor increased during adipogenesis. Stimulation of the Ang II type 1 receptor by Ang II reduced adipose conversion, whereas blockade of this receptor markedly enhanced adipogenesis. Adipocytes were able to inhibit preadipocyte differentiation in the co-culture, and this effect was abolished by blockade of the Ang II type 1 receptor. This finding points to a functional role of the RAS in the differentiation of human adipose tissue. Because AGT secretion and Ang II generation are characteristic features of adipogenesis, we postulate a paracrine negative-feedback loop that inhibits further recruitment of preadipocytes by maturing adipocytes.
Diabetes 2002 Jun
PMID:Mature adipocytes inhibit in vitro differentiation of human preadipocytes via angiotensin type 1 receptors. 1203 55

The coexistence of hypercholesterolaemia and diabetes dramatically and synergistically increases the risk of microvascular and macrovascular complications in patients. A single unifying mechanism of increased production of reactive oxygen species (ROS) by angiotensin II (Ang II) may serve as a causal link between hyperglycaemia and hypercholesterolaemia and many of the major pathways responsible for atherogenic and diabetic disorders. Several lines of evidence suggest a crucial role for Ang II-mediated oxidative stress in the pathogenesis of hyperglycaemia- and hypercholesterolemia-associated endothelial dysfunction. Endothelial dysfunction in these scenarios may be due to impaired nitric oxide (NO) synthesis and/or inactivation of endothelium-derived NO by ROS. That Ang II plays an important role in the development of atherosclerosis and glomerulosclerosis is supported by numerous studies indicating that angiotensin receptor blockers (ARBs) retard the progression of these diseases in both experimental animal models and humans. Evidence indicates that Ang II contributes to atherogenesis at both transcriptional and translational levels by upregulating adhesion molecule mRNA and protein synthesis. The recent demonstration of Ang II AT(2) receptors in the adult kidney and their potential to oppose the vasoconstrictive, antinatriuretic, and profibrotic properties of AT(1) receptors suggests that the balance of intrarenal AT(1) and AT(2) receptors may be important in determining the cellular responses to Ang II in diabetic nephropathy. Results of these studies suggest that hypercholesterolaemia and hyperglycaemia can induce a pro-inflammatory response within coronary arteries and the kidney glomerulus. This response involves production of well described macrophage chemotactic and adhesion molecules, which results in macrophage recruitment and the development of acute and chronic injury. Glomerular macrophage recruitment in experimental diabetes occurs via Ang II-stimulated monocyte chemoattractant protein (MCP)-1 expression, suggesting that the renin-angiotensin system is an important regulator of local MCP-1 expression, and strongly implicating macrophage recruitment and activation in the pathogenesis of early diabetic glomerular injury. Diabetes-associated vascular complications may also involve an activation of the nuclear factor (NF)-kappaB by hyperglycaemia. NF-kappaB activation is related to AT(1) receptor-mediated pathways, and is believed to be dependent on activation of the Rho proteins belonging to the superfamily of low molecular weight guanosine triphosphatases (GTPases) that regulate intracellular signalling. Preincubation of vascular smooth muscle cells with insulin doubled NF-kappaB transactivation stimulated by Ang II and hyperglycaemia, suggesting a potential mechanism for crosstalk between the renin-angiotensin system and hyperglycaemia. Taken together, these data suggest that activation of the renin-angiotensin system is a mechanism for the initiation and progression of inflammatory cell infiltration found in early changes common to both hypercholesterolaemia and hyperglycaemia. While the base of information regarding ARBs in high-risk patients with diabetes and hypercholesterolemia is lacking, preclinical and pilot trial data suggest that the ARBs are reno- and vasculoprotective in these patients. Therapeutic blockade of Ang II AT(1) receptors in diabetic and hypercholesterolaemic humans by ARBs, with concomitant elevation in plasma and tissue Ang II levels, may provide vascular and renal protection not only by reducing AT(1) receptor-mediated pro-oxidative effects, but also by unopposed AT(2) receptor stimulation.
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PMID:[Pathophysiological and clinical implications of AT(1) and AT(2) angiotensin II receptors in metabolic disorders: hypercholesterolaemia and diabetes]. 1203 87

The octapeptide angiotensin II (Ang II), the potent effector molecule of the renin-angiotensin-aldosterone system (RAAS), is involved in the control of blood pressure, cardiac and vascular function as well as sodium and water homeostasis. Because Ang II has also been implicated in the pathophysiology of cardiovascular diseases and renal failure, it has been of increasing interest to inhibit the RAAS at the level of its enzymes such as renin and angiotensin-converting enzyme (ACE) and receptors. At least two subtypes of angiotensin receptors have been identified: AT(1) and AT(2). The AT(1 )receptor mediates all of the known actions of Ang II in the cardiovascular system, such as vasoconstriction, increasing cardiac contractility and renal tubular sodium reabsorption, as well as vascular and cardiac hypertrophy. In contrast, less is known regarding the function of the AT(2) receptor. Evidence suggests that the AT(2) receptor inhibits cell proliferation and induces differentiation, apoptosis and regeneration. The AT(2) receptor has been shown to reverse AT(1) receptor-mediated hypertrophy, suggesting that these receptors exert opposing effects in the cardiovascular system. While renin and ACE inhibitors block the RAAS at the enzymatic level, AT receptor antagonists specifically inhibit the RAAS at the receptor site. AT(1 )receptor antagonists induce a dose-dependent blockade of Ang II-induced effects, resulting in a reduction in blood pressure, cardiac and vascular hypertrophy, proteinuria and glomerular sclerosis. It is postulated that AT(1) receptor antagonists may provide end-organ protection by blocking Ang II via the AT(1) receptor, yet leaving the AT(2) receptor unopposed. These substances have been shown to decrease morbidity and mortality of patients with heart failure and renal disease associated with diabetes.
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PMID:[Pathophysiological and clinical implications of AT(1)/AT(2) angiotensin II receptors in heart failure and coronary and renal failure]. 1203 88

We examined human hand veins to determine whether venoconstricting response to angiotensin II (Ang II) and noradrenaline (NA) was influenced by aging or such diseases as diabetes mellitus (DM) and hypertension (HT). Twenty healthy male subjects (20-73 years), and 8 male patients with non-insulin-dependent DM and 8 male patients with essential HT were included in this study. A constant dose (50 ng/min) of Ang II or increasing dose (2-256 ng/min) of NA was infused into the dorsal hand vein and its diameter was measured using a linear variable differential transformer. The constant infusion of Ang II caused rapid desensitization or tachyphylaxis. The venoconstriction by Ang II in the 8 elderly subjects (58 to 73 years) was significantly (p<0.05) larger than that in the 8 young subjects (20 to 36 years) from 6 to 18 min after the start of the infusion (after 6 min: 63.6+/-11.6 (mean+/-SD)% vs. 39.9+/-20.8%, 12 min: 34.0+/-11.9% vs. 12.0+/-12.0%). However, the venoconstriction by Ang II in the patients with DM or HT was not significantly different from that in the 9 age-matched control subjects. No significant difference in venoconstrictor response to NA was observed between the young and elderly subjects, nor between the control subjects and the patients with DM or HT. These findings indicated that venoconstrictor response to Ang II might be greater in the elderly but might not be influenced by DM nor HT.
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PMID:Vasoconstricting effect of angiotensin II in human hand veins: influence of aging, diabetes mellitus and hypertension. 1245 19


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