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Query: UMLS:C0011881 (diabetic nephropathy)
 10,836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The kidney is one of the principal target organs of hypertension and most diseases of the kidney are associated with blood pressure elevation. Studies in animal models of hypertensive renal disease have provided insights into the complex relationship between systemic and glomerular hypertension. The intrarenal renin-angiotensin system (RAS) appears to play an important role in the pathogenesis of progressive glomerular injury. Thus, angiotensin converting enzyme inhibitors (ACEi) may have a specific therapeutic advantage in the treatment of hypertension associated with progressive renal disease. However, in contrast to their possible renoprotective effect in diabetic nephropathy or in renal hypertension, there are increasing evidence that, in the presence of a reduction in renal perfusion, intrarenal haemodynamic effect of ACEi may lead to compromised renal function. ACEi appear to have dual effects on renal function depending on the setting in which they are administered.
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PMID:Ace inhibition in renal disease: risks and benefits. 851 8

Patients who develop diabetic nephropathy, one of the leading causes of end-stage renal diseases in Western communities, have an increased red cell Li+/Na+ countertransport (CT). Li+/Na+ CT is a membrane function which exchanges intracellular Li for extracellular Na in vitro. High Li+/Na+ CT reflects abnormal kinetic properties of red cell membrane Na/H exchange. A widespread abnormality of Na/H exchange could play a major role in the pathogenesis of diabetic nephropathy as well as of cardiovascular diseases since Na/H exchange is involved in the regulation of cell pH and cell volume; in the cellular response to hormones, mitogens, and growth factors; and in the renal reabsorption of Na and bicarbonate. Li+/Na+ CT is under genetic control and raised in a subgroup of patients with essential hypertension. Among these patients, high Li+/Na+ CT is associated with increased glomerular filtration rate, filtration fraction, proximal fractional Na reabsorption, microalbuminuria, plasma renin activity, and kidney and cardiac volume. Increased Li+/Na+ CT is often associated with hyperlipidemia, hyperuricemia, reduced insulin sensitivity, and obesity. The whole of these observations may explain why patients with diabetes or essential hypertension and increased Li/Na CT are at risk of early renal and cardiac impairment.
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PMID:Red blood cell Li+/Na+ exchange in patients with diabetic nephropathy and essential hypertension: therapeutic implications. 851 86

Apart from near normal metabolic control, early treatment of an increase in blood pressure in diabetic patients with nephropathy, is one of the most important therapeutic methods to prevent further progression of this complication. Long-term studies, recently published, suggest that ACE inhibitors have a beneficial effect on albuminuria and progression of nephropathy, irrespective of their hemodynamic effects. However, the mechanism by which ACE inhibitors exert these positive effects on glomerular pathology is still unclear. Several non-hemodynamic factors have been identified as being involved in the pathogenesis of diabetic nephropathy: (a) changes in the composition of glomerular basement membrane due to a changed metabolism of the proteins which make up this structure; consequences are an impairment of the filtration properties, onset of proteinuria as well as thickening of basement membrane; (b) Mesangial expansion due to an overproduction of mesangial matrix and deposition of proteins as well as (c) impairment of mesangial clearance function; consequences are development of glomerulosclerosis and reduction of filtration surface. It is known that the renin-angiotensin-system is stimulated in diabetic patients with nephropathy and that angiotensin II influences the synthesis of glomerular and mesangial proteins as well as the function of mesangial cells. Hypothetically, these points could explain the beneficial effects of ACE-inhibitors on the progression of diabetic nephropathy.
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PMID:ACE inhibitors and diabetic nephropathy: clinical and experimental findings. 851 36

During long-term treatment of arterial hypertension with calcium antagonists of the dihydropyridine type activation of the sympathetic nervous system and subsequently also of the renin-angiotensin-aldosterone system persists, while the haemodynamic reaction to vasodilatation, manifested by an elevated pulse rate and minute volume from the initial stage of therapy, recedes. In type II diabetics the basal and stimulated response of the renin-angiotensin-aldosterone system is reduced. The administration of calcium antagonists of the dihydropyridine type does not stimulate significantly the renin-angiotensin-aldosterone system as the starting function of the sympathetic nervous system is impaired within the framework of vegetative neuropathy. In almost 20% NIDDM plasma renin activity and aldosterone do not respond to furosemide administration and the vertical posture. In others the response is found but takes place at reduced levels. Hyporeninaemic hypoaldosteronism is thus manifested not so much by a drop of plasma renin and aldosterone beneath the lower range of reference values as by a reduced response to stimulation. Functional hyporeninaemic hypoaldosteronism is another, frequent late complication of diabetes. In advanced forms a further block of the renin-angiotensin-aldosterone system by ACE inhibitors can then produce, even in the absence of diabetic nephropathy, in the stage of chronic renal failure dangerous hyperkaliaemia which may threaten the patient. Dynamic examination of the sympathetic nerve and the renin-angiotensin-aldosterone system makes it possible to predict this condition. In practice it is necessary in diabetics with arterial hypertension after starting with ACE inhibitors during the first days to monitor repeatedly plasma potassium and creatinine. ACE inhibitors and calcium antagonists are otherwise for diabetics drugs of first choice which can arrest the progression of nephropathy, effectively reduced the blood pressure without causing deterioration of insulin resistance and hyperlipoproteinaemia and lead even to regression of hypertrophy of the vascular wall and left ventricle.
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PMID:[The effect of long-term treatment of arterial hypertension with Ca antagonists on the renin-angiotensin-aldosterone system in diabetics. Hyporeninemic hypoaldosteronism]. 857 95

Genotypic abnormalities of the renin-ANG system have been suggested as a risk factor for the development of diabetic nephropathy. Cleavage of angiotensinogen is the rate-limiting step in the activation of the renin-ANG system. The TT genotype of a polymorphism encoding threonine instead of methionine (M235T) has been associated not only with increased plasma angiotensinogen concentration but also with essential hypertension. In addition, a polymorphism in the angiotensinogen gene substituting methionine for threonine (T174M) has been associated with hypertension in nondiabetic populations. We studied the relationship between these polymorphisms in the angiotensinogen gene in IDDM patients with diabetic nephropathy (121 men, 74 women, age 40.9 +/- 10 years, diabetes duration 27 +/- 8 years). There was no difference in M235T genotype distribution between IDDM patients with diabetic nephropathy and those with normoalbuminuria: 73/97/25 (37/50/13%) vs. 67/95/23 (36/52/12%) had MM/MT/TT genotypes, respectively. No difference in distribution of T174M genotypes between nephropathic and normoalbuminuric IDDM patients was observed either: 148/44/1 (77/23/0.5%) vs. 141/42/2 (76/23/1%) had TT/TM/MM genotypes, respectively. In patients with nephropathy, systolic blood pressure was higher (161 +/- 22 mmHg [mean +/- SD]) in patients carrying TT genotype of the M235T angiotensinogen polymorphism as compared with patients with MM or MT genotypes (150 +/- 23 mmHg; P = 0.03). We conclude that neither the M235T nor the T174M polymorphism in the angiotensinogen gene contributes to genetic susceptibility to diabetic nephropathy in white IDDM patients, whereas the TT genotype of the M235T is associated with elevated blood pressure in patients with diabetic nephropathy.
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PMID:Angiotensinogen gene polymorphisms in IDDM patients with diabetic nephropathy. 859 44

Arterial hypertension increase progression of late diabetic complications. Renin-angiotensin-aldosterone system plays an important role in the regulation of arterial pressure. The aim of the study was the assessment of plasma renin activity (PRA) and aldosterone (aldo) in type I euglycaemic diabetic patients on intensive insulin treatment without autonomic neuropathy. 30 type I diabetic patients (including 11 with nephropathy defined as urinary albumin excretion > 30 mg/24 h and 19 without albuminuria) were admitted into the trial. Mean age 31.9 + 1.4 years, duration time of disease was 9.1 + 1.5 years, HbA1c level 7.6 + 0.25%; GFR 124.7 + 3.9 ml/min/1.73 m2 (135.8 + 5.1 in subgroup with nephropathy and 118.2 + 5.08 in non-nephropathic group). Blood samples were taken during normal sodium intake (120 mmol/24 h) after 0.5 h supine. PRA was significantly lower in type I diabetics vs control (0.27 + 0.04, 0.61 + 0.09 pmol/l/s respectively-p < 0.005). PRA was significantly lower both in nephropathic and non-nephropathic diabetic group vs control (respectively 0.22 + 0.06 and 0.31 + 0.05-p < 0.05). Aldo in diabetic patients and in subgroups with and without nephropathy was significantly lower vs controls (respectively 173 + 12.9, 165.1 + 14.4, 182.1 + 18.8 and 257.1 + 24.1 pmol/l; p < 0.01, p < 0.05). Significant differences in hormonal changes between diabetic patients with and without nephropathy were not found. Basing upon the results we conclude that in euglycemic intensively insulin treated type I diabetic patients without neuropathy presented decreased level of PRA and aldo. Early stage of diabetic nephropathy does not influence the examined hormones level.
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PMID:[Activity of the renin-angiotensin-aldosterone system in euglycemic type I diabetic patients on intensive insulin treatment without diabetic neuropathy]. 859 57

One of the characteristics of early diabetic nephropathy is glomerular hyperfiltration and hyperperfusion. Many factors have been suggested to induce glomerular hyperperfusion among which are an increased production of vasodilatory prostanoids, an increased synthesis of nitric oxide, a reduced responsiveness of afferent glomerular arterioles to vasoconstrictor stimuli due to diabetic metabolic disturbances and a decreased receptor density for angiotensin II. It has been known for years that angiotensin II is formed locally due to the local activation of the renin angiotensin system. The local angiotensin II concentration, however, is not only regulated by the synthesis rate but also by the local degradation through activation of an aminopeptidase. The main finding of the present study was that the mRNA expression and activity of the angiotensin II degrading enzyme, angiotensinase A, was increased twofold in diabetic rats at 5 weeks and that the increase in mRNA expression was suppressed by insulin therapy and short-term treatment with the angiotensin II antagonist saralasin, whereas angiotensinase A enzyme activity was only reduced by saralasin and not by insulin. These results demonstrate that the angiotensin II degrading exopeptidase angiotensinase A is activated in diabetic glomeruli. This increased activity may be an additional mechanism to explain glomerular hyperfiltration and hyperperfusion in early diabetic nephropathy.
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PMID:Angiotensinase A gene expression and enzyme activity in isolated glomeruli of diabetic rats. 872 72

The renin-angiotensin system (RAS) has been implicated in the pathogenesis of diabetic nephropathy. In diabetes, renal RAS components are dysregulated, potentially increasing renal RAS effects. To explore the renal RAS, studies were conducted in control and diabetic rats. In both groups, intravenous angiotensin (ANG) I and ANG II produced similar increases in mean arterial pressure (MAP). In contrast, glomerular filtration rate defined only in diabetic rats. Renal plasma flow fell in both groups but decreased more in diabetic rats. Additional groups were given the same dose of ANG I directly into the left renal artery, and hemodynamics were studied in the treated and untreated kidneys. In contrast to the intravenous studies, intra-arterial ANG I had no effect on MAP in either group. The renal hemodynamic effects were similar to those in intravenous studies. Additionally, diabetic rats exhibited enhanced hemodynamic sensitivity in the untreated kidney, suggesting that renal effects could occur at nonpressor concentrations of circulating ANG II. Thus renal (but not systemic) responsiveness to angiotensins is enhanced in diabetic rats.
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PMID:Enhanced renal sensitivity to angiotensin actions in diabetes mellitus in the rat. 885 21

Premature cardiovascular disease is common in insulin-dependent diabetic (IDDM) patients who develop diabetic nephropathy. Genetic polymorphism within the renin-angiotensin system has been implicated in the aetiology of a number of cardiovascular disorders; these loci are therefore candidate genes for susceptibility to diabetic renal disease. We have examined the angiotensin converting enzyme insertion/deletion polymorphism and angiotensinogen methionine 235 threonine polymorphism in a large cohort of Caucasian patients with IDDM and diabetic nephropathy. Patients were classified as having nephropathy by the presence of persistent dipstick positive proteinuria (in the absence of other causes), retinopathy and hypertension (n = 242). Three groups were examined for comparison: ethnically matched non-diabetic subjects (n = 187); a geographically defined cohort of newly diagnosed diabetic patients (n = 341); and IDDM patients with long duration of disease (> 15 years) and no evidence of overt nephropathy (n = 166). No significant difference was seen in distribution of angiotensin converting enzyme or angiotensinogen genotypes between IDDM patients with nephropathy and recently diagnosed diabetic subjects (p = 0.282 and 0.584, respectively), nor the long-duration non-nephropathy diabetic subjects (p = 0.701 and 0.190, respectively). We conclude that these genetic loci are unlikely to influence susceptibility to diabetic nephropathy in IDDM in the United Kingdom.
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PMID:Examination of two genetic polymorphisms within the renin-angiotensin system: no evidence for an association with nephropathy in IDDM. 887 96

Hypertension is seen in approximately 85% of IDDM patients with diabetic nephropathy and blood pressure elevation is an early event in the development of this complication. In IDDM patients with clinical nephropathy, a positive correlation has been demonstrated between the blood pressure and the urinary albumin excretion and reduction of blood pressure reduces albuminuria as well as the rate of decline in glomerular filtration rate. Also extrarenal abnormalities such as retinopathy, cardiovascular diseases and signs of endothelial dysfunction, sometimes seen in non-diabetics with severe and/or prolonged hypertension, are frequently demonstrated in IDDM patients with clinical nephropathy. The aim of the present study was to provide circumstantial evidence for the thesis that hypertension in IDDM patients with nephropathy is secondary to the kidney involvement and not the cause of the kidney disease. Furthermore, by familial and physiological studies the review also aimed to contribute to the understanding of the pathogenesis of hypertension in patients with clinical nephropathy. Finally the question of optimal pharmacological antihypertensive treatment was discussed. It was demonstrated that in IDDM patients with elevated urinary albumin excretion above normal level the prevalence of hypertension is 60%, whereas in patients without signs of renal impairment hypertension is not more prevalent as in the age and sex-matched background population (about 4% in both groups). Based upon the observation, that some of these IDDM patients with hypertension but normal UAE were hypertensive for many years, we designated this group as IDDM patients with essential hypertension for further studies. In this group, we had the opportunity to study the association between blood pressure and the development of extrarenal complications in patients with IDDM. The group with essential hypertension and IDDM showed to have less retinopathy compared with diabetics with similar blood pressure but elevated UAE. In contrast to the hypertensive patients with nephropathy, a normal transcapillary escape rate of albumin and normal plasma levels of von Willebrand factor, of angiotensin-converting-enzyme and of inactive renin were demonstrated in the former group of patients. Thus, the extrarenal abnormalities found in IDDM patients with hypertension are more closely associated to the presence of albuminuria than to the elevation of blood pressure, indirectly supporting the hypothesis that hypertension per se is not the cause of these abnormalities in the IDDM patients with nephropathy. Furthermore, the present study does not disclose a genetic disposition to hypertension in IDDM patients with elevated UAE.
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PMID:Hypertension in insulin-dependent diabetes. 890 79


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