Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011881 (diabetic nephropathy)
 10,836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Blockade of the renin-angiotensin system is now recognized as an effective approach to the treatment of hypertension and congestive heart failure. Today, it is possible to antagonize the effects of angiotensin II more specifically by blocking its receptors by using nonpeptide receptor antagonists. These compounds that first have been used to recognize the various subtypes of angiotensin II receptors are now available clinically. Four of them have recently been launched on the market and several others are preregistered for the treatment of hypertension. These new molecules are as effective as ACE inhibitors, calcium antagonists and beta-blockers in lowering blood pressure in hypertensive patients. When compared to ACE inhibitors, they appear to have comparable favorable effects on systemic and renal hemodynamic properties. One of the major characteristics of angiotensin II receptor antagonists as a class is the excellent tolerability with an incidence of side effects that is generally similar to that of placebo. Large clinical trials are now underway to demonstrate the long-term benefits of these agents in hypertension, heart failure and type II diabetic nephropathy.
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PMID:Angiotensin II receptor antagonists in hypertension. 983 93

Diabetic nephropathy often co-exists with other manifestations of microangiopathy, in particular retinopathy. Recent clinical evidence suggests that inhibition of the renin-angiotensin system in humans can delay the development and/or progression of diabetic nephropathy and perhaps also retinopathy. The benefits of this therapeutic strategy may in part be explained by inhibition of the nonhaemodynamic actions of angiotensin II (Ang II). The recognized nonhaemodynamic actions of Ang II include the augmented release of many growth factors. Ang II can stimulate the release of vascular endothelial growth factor (VEGF) from human vascular tissues. VEGF is a family of potent cytokines which act to induce angiogenesis and markedly increase microvascular permeability. VEGF is abundantly expressed in the renal glomerulus, specifically within the podocyte, where its function is unknown. VEGF is also expressed in the retina and increased retinal VEGF expression occurs in diabetes and has been implicated in the pathogenesis of diabetic retinopathy. This review considers the potential clinical significance of Ang II-induced VEGF expression, if any, in the pathogenesis of diabetic nephropathy and retinopathy.
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PMID:A potential role for angiotensin II-induced vascular endothelial growth factor expression in the pathogenesis of diabetic nephropathy? 993 Mar 79

Clinical, experimental, biochemical, and molecular biologic studies all invoke an important role for the renin-angiotensin system (RAS) in the pathogenesis of diabetic complications. Studies of pharmacologic interruption of the RAS with angiotensin-converting enzyme (ACE) inhibition have implicated this hormonal system in the progression of diabetic nephropathy, both experimentally and clinically. Preliminary evidence also suggests a beneficial effect of angiotensin II (Ang II) receptor antagonists. The relative roles of the systemic vs. intrarenal RAS in the pathogenesis of diabetic nephropathy have recently been evaluated. Though plasma renin is generally low, it is not yet clear whether RAS component processing is normal in diabetes; there may be subtle changes in Ang II metabolism which sustain relatively higher plasma Ang II levels. Furthermore, the intrarenal RAS may not be suppressed. Renal renin levels tend to be disproportionately elevated, as compared to plasma renin values. Renal Ang II levels are normal, and renal mRNAs for RAS components have been variable, though not suppressed. In general, lack of RAS suppression (despite plasma volume and increased exchangeable sodium) may indicate inappropriate activity of the RAS in diabetes. Indeed, disproportionate activity of the intrarenal RAS may be a proximate cause of the observed suppression of the systemic RAS. RAS-mediated injury may occur via stimulation of a number of sclerosing mediators, and there is evidence that hyperglycemia acts synergistically with Ang II to promote cellular injury. Together, these recent investigations lend further support to the notion that the RAS plays an important role in diabetic nephropathy, and are beginning to shed light on the mechanisms of progressive renal injury.
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PMID:Physiologic actions and molecular expression of the renin-angiotensin system in the diabetic rat. 993 Mar 80

Approximately 150 million people worldwide have diabetes mellitus, of whom 90% are type II diabetics. It is therefore of no surprise that diabetic nephropathy has become the leading cause of end-stage renal disease. Opposite to what has been known previously, kidney disease is at least as common in type II as in type I diabetes. However, because the majority of type II diabetics has hypertension for many years before diabetes mellitus becomes clinically relevant, renal lesions are often heterogeneous with frequent exclusive presence of ischemic changes. For the treatment of hypertension in diabetics without nephropathy (no microalbuminuria), drugs that exert beneficial effects or are at least neutral with respect to lipid and glucose metabolism, such as ACE inhibitors, angiotensin II-receptor antagonists, non-dihydropyridine-calcium channel blockers and the thiazide-like indapamide, are to be preferred. Although metabolically neutral, dihydropyridine calcium channel blockers should be used with caution, since an increase in cardiovascular morbidity and mortality in type II diabetics treated with these compounds has most recently been described. Once that diabetic nephropathy is established, blood pressure should be lowered to 120/80 mmHg (measured in seated position). Antihypertensive treatment should primarily be based on ACE inhibitors; angiotensin II-receptor antagonists are a valuable alternative if ACE inhibitors are not tolerated. Both ACE inhibitors and angiotensin II-receptor antagonists should be used with high caution in elderly patients with severe atherosclerosis in whom acute renal failure could occur due to the presence of bilateral renal artery stenosis. Newer studies indicate that non-dihydropyridine calcium channel blockers such as verapamil and diltiazem may be as effective as ACE inhibitors in preserving renal function in diabetic nephropathy. A fix-dose combination of the ACE inhibitor trandolapril with verapamil is now available; it should be reserved for patients whose blood pressure and/or proteinuria can not be adequately controlled with ACE inhibitors. Finally, indapamide is the only antihypertensive diuretic with nephroprotective properties.
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PMID:[Antihypertensive therapy in diabetes mellitus]. 1006 31

The renin-angiotensin system plays an important role in the progression of chronic renal disease. Although the expression of renin and angiotensin-converting enzyme in experimental and human renal disease has been well characterized, no information is available regarding human angiotensin type 1 (AT1) receptor expression. The net effect of renin depends on AT1 receptor expression, among other factors. Receptor expression was determined in renal biopsy samples (including all tissue components) and isolated glomeruli from patients with glomerulonephritis (GN) or diabetic nephropathy (non-insulin-dependent diabetes mellitus). Biopsy samples and isolated glomeruli from tumor-free tissue from tumor nephrectomies served as controls. Human AT1 receptor gene expression was determined by quantitative reverse transcription-PCR, using an AT1 receptor deletion mutant as the internal standard. In whole biopsy samples from 37 patients with various types of GN, AT1 receptor mRNA levels were lower, compared with nine control biopsy samples (P < 0.001). AT1 receptor mRNA levels were also significantly lower (P < 0.001) in eight samples from patients with diabetic nephropathy. In microdissected glomeruli, AT1 receptor gene expression was significantly lower in samples from patients (n = 22) with various types of GN, compared with 12 microdissected tumor nephrectomy control samples (P < 0.0023). It is concluded that AT1 receptor mRNA expression is low in glomeruli of patients with chronic renal disease. This may reflect a regulatory response to (inappropriately) high intrarenal angiotensin II concentrations.
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PMID:Angiotensin II receptor type 1 gene expression in human glomerulonephritis and diabetes mellitus. 1007 5

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is a new genetic model of non-insulin-dependent diabetes mellitus (NIDDM). We investigated whether treatment with an angiotensin II (ANGII) subtype-1 receptor antagonist delays the onset of NIDDM and attenuates diabetic nephropathy in the OLETF rat. OLETF rats fed a regular chow were treated with ANGII subtype-1 receptor antagonists (E4177 or TA606) for 22 weeks. Hemodynamic changes, glucose metabolism, and the effects on diabetic nephropathy were examined. Systolic blood pressure increased in OLETF rats in an age-dependent manner. OLETF rats exhibited increases in plasma concentrations of glucose and insulin and developed glucosuria at the age of 28 weeks. The changes in glucose metabolism were associated with proteinuria and an increase in urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG). Morphologic investigation revealed nodular lesions in glomeruli in the OLETF rats. The ANGII receptor antagonist treatment abolished the blood pressure elevation. However, the treatment did not affect plasma glucose and insulin levels and did not significantly reduce glucosuria. Nodular lesions in glomeruli were not improved by the treatment. However, the receptor antagonists significantly reduced proteinuria and urinary NAG excretion. Multivariate analyses revealed that proteinuria was determined by systolic blood pressure, lipid metabolism, and glucose levels in plasma. ANGII subtype-1 antagonism does not improve glucose metabolism in the OLETF rat model of NIDDM, which has abnormalities in the glucose-uptake system. Blood pressure elevation and part of the proteinuria associated with NIDDM depends on the renin-angiotensin system rather than glucose metabolisms per se.
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PMID:Angiotensin II subtype-1 receptor antagonists improve hemodynamic and renal changes without affecting glucose metabolisms in genetic rat model of non-insulin-dependent diabetes mellitus. 1007 80

Angiotensin I-converting enzyme (ACE) inhibitors are commonly used for the treatment of hypertension, progressive chronic renal disease, diabetic nephropathy, and congestive heart failure. Because angiotensin II acts through membrane bound type 1 (AT1) and type 2 (AT2) receptors, ACE inhibitors and angiotensin II-receptor antagonists have distinct effects. ACE inhibitors inhibit production of angiotensin II thus suppressing the action of angiotensin II on both AT1 and AT2. In contrast, the effect of AT1-receptor antagonists is to selectively block the activation of the AT1 receptor. This AT1-receptor blockade leaves the AT2 receptors unopposed to elevated levels of endogenous angiotensin II. Thus, there may be an advantage of AT1-receptor blockade over ACE inhibition in the management of a variety of chronic vascular diseases, including chronic glomerulonephritis and other glomerular diseases. In a clinical trial candesartan, an AT1-receptor antagonist, effectively lowered urinary protein excretion in patients with chronic glomerular nephritis. Evidence indicates that functionally active AT1 receptors, as well as AT2 receptors, are present in both afferent and efferent arteriole of the glomerulus, and that angiotensin II induces afferent and efferent arteriolar dilatation via AT2 receptors.
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PMID:Effects of candesartan on the proteinuria of chronic glomerulonephritis. 1007 22

Hyperglycemia causes capillary vasodilation and high glomerular capillary hydraulic pressure, which lead to glomerulosclerosis and hypertension in type 1 diabetic subjects. The insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene can modulate risk of nephropathy due to hyperglycemia, and the II genotype (producing low plasma ACE concentrations and probably reduced renal angiotensin II generation and kinin inactivation) may protect against diabetic nephropathy. We tested the possible interaction between ACE I/D polymorphism and uncontrolled type 1 diabetes by measuring glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) during normoglycemia ( approximately 5 mmol/L) and hyperglycemia ( approximately 15 mmol/L) in 9 normoalbuminuric, normotensive type 1 diabetic subjects with the II genotype and 18 matched controls with the ID or DD genotype. Baseline GFR (145+/-22 mL/min per 1.73 m2) and ERPF (636+/-69 mL/min per 1.73 m2) of II subjects declined by 8+/-10% and 10+/-9%, respectively, during hyperglycemia; whereas baseline GFR (138+/-16 mL/min per 1.73 m2) and ERPF (607+/-93 mL/min per 1.73 m2) increased by 4+/-7% and 6+/-11%, respectively, in ID and DD subjects (II versus ID or DD subjects: P=0.0007 and P=0.0005, for GFR and ERPF, respectively). The changes in renal hemodynamics of subjects carrying 1 or 2 D alleles were compatible, with a mainly preglomerular vasodilation induced by hyperglycemia, proportional to plasma ACE concentration (P=0.024); this was not observed in subjects with the II genotype. Thus, type 1 diabetic individuals with the II genotype are resistant to glomerular changes induced by hyperglycemia, providing a basis for their reduced risk of nephropathy.
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PMID:Renal changes on hyperglycemia and angiotensin-converting enzyme in type 1 diabetes. 1008 86

The benefit of angiotensin-converting enzyme (ACE) inhibitor (i) therapy in diabetic glomerulosclerosis is thought to be largely the result of attenuation of angiotensin II (AngII) effects on blood pressure, glomerular hemodynamics and hypertrophy, and tissue fibrosis. The present study was undertaken to determine whether the addition of AngII receptor antagonist therapy to ACEi therapy in diabetic nephropathy results in attenuation of AngII effects beyond that achieved by ACEi therapy alone. Seven patients were studied as inpatients on the General Clinical Research Center each for 3 consecutive weeks as follows: week 1, the patients' usual regimen which included daily oral moderate to high dose ACEi therapy; week 2, the patients' usual regimen plus oral losartan (an antagonist (a) of the angiotensin type 1 receptor, AT1) 50 mg (n = 3) or 100 mg (n = 4) daily; week 3, return to the patients' usual regimen. Diet, physical activity, and blood glucose were held as constant as possible during the three weeks of daily testing. We found that plasma renin levels increased significantly during combination therapy and then returned to baseline values with discontinuation of AT1a therapy: mean baseline renin values (week 1) 3.0 ng/ml/min +/- 1.1 SE, mean renin values during combination therapy (week 2) 7.0 ng/ml/min +/- 3.2 (p = 0.0078 by Wilcoxon rank sum test), mean renin values after discontinuation of AT1a therapy (week 3) 3.9 ng/ml/min +/- 2.0 (NS compared to baseline values). In addition, 2 patients developed transient hypotension when losartan therapy was initiated. During this short-term study, 24-hour proteinuria, serum creatinine, serum potassium, and plasma aldosterone were not changed significantly by combination therapy. We conclude that in patients with diabetic nephropathy addition of AT1a therapy to ACEi therapy attenuates AngII effects better than ACEi therapy alone. We suggest that combination therapy for the management of diabetic glomerulosclerosis merits further investigation.
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PMID:Combination ACE inhibitor and angiotensin II receptor antagonist therapy in diabetic nephropathy. 1008 42

The renin-angiotensin-aldosterone system (RAAS) plays an important role in both the short-term and long-term regulation of arterial blood pressure, and fluid and electrolyte balance. The RAAS is a dual hormone system, serving as both a circulating and a local tissue hormone system (i.e., local mediator) as well as neurotransmitter or neuromediator functions in CNS. Control of blood pressure by the RAAS is exerted through multiple actions of angiotensin II, a small peptide which is a potent vasoconstrictor hormone implicated in the genesis and maintenance of hypertension. Hypertension is a primary risk factor associated with cardiovascular, cerebral and renal vascular disease. One of the approaches to the treatment of hypertension, which may be considered as a major scientific advancement, involves the use of drugs affecting the RAAS. Pharmacological interruption of the RAAS was initially employed in the late 1970s with the advent of the angiotensin converting enzyme (ACE) inhibitor, captopril. ACE inhibitors have since gained widespread use in the treatment of mild to moderate hypertension, congestive heart failure, myocardial infarction, and diabetic nephropathy. As the roles of the RAAS in the pathophysiology of several diseases was explored, so did the realization of the importance of inhibiting the actions of angiotensin II. Although ACE inhibitors are well tolerated, they are also involved in the activation of bradykinin, enkephalins, and other biologically active peptides. These actions result in adverse effects such as cough, increased bronchial reactivity, and angioedema. Thus, the goal of achieving a more specific blockade of the effects of angiotensin II than is possible with ACE inhibition. The introduction of the nonpeptide angiotensin II receptor antagonist losartan in 1995 marked the achievement of this objective and has opened new vistas in understanding and controlling the additional biological effects of angiotensin II. Complementary investigations into the cloning and sequencing of angiotensin II receptors have demonstrated the existence of a family of angiotensin II receptor subtypes. Two major types of angiotensin II receptors have been identified in humans. The type 1 receptor (AT1) mediates most known effects of angiotensin II. The type 2 receptor (AT2), for which no precise function was known in the past, has gained importance recently and new mechanisms of intracellular signalling have been proposed. This review presents recent advances in angiotensin II receptor pharmacology, molecular biology, and signal transduction, with particular reference to the AT1 receptor. Excellent reviews have appeared recently on this subject.
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PMID:Angiotensin II receptors-antagonists, molecular biology, and signal transduction. 1009 99


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