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

In order to study the role of the renin-angiotensin system in patients with diabetic nephropathy, renin release and the juxtaglomerular apparatus were studied in 17 diabetic patients with proteinuria and in 23 without proteinuria; 8 normal subjects were used for conctrls. Despite hypertension and marked arteriosclerosis, plasma renin activity (supine posture) was normal; however, the renin response to salt restriction and upright posture was less in the diabetic patients with proteinuria than in the controls. Renal renin content, determined at autopsy, was also normal. Examination of the juxtaglomerular apparatus in the diabetic patients with proteinuria revealed hyalinization of the afferent and efferent arterioles in most of the glomeruli and various degrees of destruction of the juxtaglomerular cells. The findings suggest that renin production is not increased in diabetic patients with proteinuria plus marked vascular damage, and that the renin-angiotensin system in patients with diabetic nephropathy apparently does not play an important role in the exacerbation of hypertension or the degree of vascular damage.
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PMID:Renin and the juxtaglomerular apparatus in diabetic nephropathy. 61 49

Diabetes mellitus (DM)-linked metabolic alterations and hypertension concomitantly accelerate or precipitate cerebrovascular and coronary heart disease, nephropathy, retinopathy and widespread macroangiopathy, thereby conferring to diabetic patients a very high risk of morbidity, disability and early death. Therefore, the long-term care for diabetic patients should be aimed at concomitant metabolic and blood pressure (BP) control. Dietary measures are indispensable; a high fibre, low fat, low salt diet is recommended, complemented with caloric restriction and physical exercise when body weight is above the ideal. Antidiabetic pharmacotherapy involves an unresolved dilemma. The desired achievement of euglycemia necessitates effective levels of insulin, but hyperinsulinemia (due to parenteral [over]treatment in insulin-dependent DM) is suspected to promote atherogenesis and represents a coronary risk factor and perhaps even facilitates hypertension. Considering antihypertensive pharmacotherapy, thiazide-type or loop diuretics are problematic drugs in DM because they can aggravate metabolic alterations. These agents also seem to exert only a limited preventive or regressive effect on left ventricular hypertrophy (LVH); beta-blockers are also not considered ideal, since they decrease the awareness of hypoglycemia and tend to promote glucose intolerance. Unselective beta-blockers in particular promote peripheral ischemia and insulin-induced hypoglycemia, while beta-blockers without intrinsic sympathomimetic activity lower serum HDL-cholesterol. Calcium antagonists and ACE inhibitors have equivalent antihypertensive efficacy, do not impair carbohydrate and lipid homeostasis or peripheral perfusion and can effectively improve LVH. Certain ACE inhibitors may even slightly ameliorate abnormal insulin sensitivity and plasma glucose levels. While alpha-blockers share most of these desirable properties, these agents are more prone to precipitate orthostatic hypotension in the diabetic patient. The non-thiazide diuretic indapamide and the serotonin2-antagonist ketanserin also combine antihypertensive efficacy with metabolic neutrality. The ultimate goal of therapy is to improve life prognosis. In essential hypertension, conventional drug treatment based on diuretics in high dosage satisfactorily reduced cerebrovascular but not coronary complications or sudden death. In diabetic patients, the influence of antihypertensive therapy on prognosis has not been assessed prospectively. Based on retrospective analyses, Warram et al reported a 3.8 times higher mortality in diabetics treated with diuretics alone, than in diabetics with untreated hypertension (Arch Intern Med. 1991;151:1350). H. H. Parving calculated that effective BP control in patients with diabetic nephropathy might reduce 10 year-mortality from about 65 to 20 percent (J Hypertension. 1990; 8[Suppl 7]:187).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Antihypertensive therapy in diabetic patients. 128 10

1. To dissociate the effects on the development of diabetic renal injury of angiotensin converting enzyme (ACE) inhibition per se, and a reduction in systemic blood pressure, we have studied the effects of chronic ramapril treatment in streptozotocin diabetic spontaneously hypertensive rats, with modulation of the hypotensive effect by a high salt diet. 2. Three weeks following uninephrectomy and induction of diabetes with streptozotocin, spontaneously hypertensive rats were allocated to three treatment groups. Groups 1 and 2 received 1% sodium chloride and Group 3 water as drinking solution. Groups 2 and 3 received 0.4 mg/kg per day ramapril in drinking solution over the subsequent 2 month study period. 3. Sodium chloride drinking solution (1%) completely prevented any hypotensive effect of ramapril. Blood pressure was reduced in Group 3 rats over the entire period of study, when compared with Group 2 rats (P less than 0.001). 4. Urinary protein excretion progressively increased in Group 1 and 2 rats, and was significantly reduced (P less than 0.001) in Group 3. After 2 months treatment, urinary protein (expressed as mean and s.e.m.) was 160 +/- 30 mg/day in Group 1, 240 +/- 50 mg/day in Group 2, and 60 +/- 11 mg/day in Group 3. 5. Angiotensin converting enzyme inhibition per se was not associated with a reduced protein excretion in diabetic nephropathy, requiring concomitant control of systemic blood pressure to become renoprotective.
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PMID:High salt diet ameliorates effects of angiotensin converting enzyme inhibition in spontaneously hypertensive streptozotocin diabetic rats. 214 Mar 3

The chronic hyperglycemia in diabetes mellitus enhances the nonenzymic glycation of structural proteins possibly increasing the formation of highly reactive advanced glycation end products (AGE). These protein changes might be involved in tissue-damaging mechanisms leading to diabetic complications, including diabetic nephropathy. To simulate these events, an in vitro model, based on isolated human glomerular basement membrane (hGBM), has been developed. In this study we have investigated the extent of AGE formation and the binding changes induced by the nonenzymic glycation of hGBM. An enriched fraction of hGBM was isolated from normal human kidneys and glycated in vitro by incubation with glucose (500 mmol/l) at 37 degrees C for 10 days. The presence of AGE was investigated by two methods - spectrofluorescence and the diazonium salt reaction - both specific for this type of chemical entity. The binding capacity of glycated hGBM was tested by a 10-day incubation with human insulin, albumin, immunoglobulin G and fibrinogen. Higher relative spectrofluorescence values at 440 nm emission (20.0 +/- 2.0 vs. 12.5 +/- 5.0) and higher absorbance values at 492 nm (0.798 +/- 0.063 vs. 0.429 +/- 0.228) indicated the presence of increased levels of AGE in glycated vs. native hGBM. Insulin and the three proteins were bound to hGBM in increased amounts after its glycation (p less than 0.05). The results obtained in this in vitro model confirm that enhanced nonenzymic glycation of hGBM induces the formation of AGE and possibly, through these compounds, alters its physicochemical and binding properties. This reaction might contribute to the mechanisms eventually leading to diabetic nephropathy.
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PMID:Nonenzymic glycation of isolated human glomerular basement membrane changes its physicochemical characteristics and binding properties. 273 62

Favourable results with the use of inhibitors of the angiotension I-converting enzyme in the therapy not only of high-renin but also normo-renin and low-renin hypertension revived interest in research in the area of the renin-angiotensin (RAS) system. The use of classical radioimmunological, radiohistochemical receptor studies as well as of recent methods of molecular biology and pathology revealed that for the regulation of blood pressure and the extracellular volume and pathogenesis of hypertension not only RAS components in systemic blood are important but also local tissue RAS with an autocrine and paracrine action at the site of its origin. Cerebral RAS participates in the central cardiovascular regulation, in the control of the salt and water intake, the secretion of antidiuretic hormone and ACTH. In the cardiovascular apparatus RAS is responsible not only for vasoconstriction but it acts also as a growth factor promoting the development of cardiac and vascular hypertrophy. In the kidneys RAS decides on the blood flow, its distribution, glomerular filtration. Its excessive stimulation may contribute in arterial hypertension, diabetic nephropathy and in residual nephrons during chronic renal failure, to the change from functional hyperfiltration to irreversible structural damage of the nephron. Inhibitors of the converting enzyme not only reduce the peripheral vascular resistance in arterial hypertension but influence also the tissue production of angiotensin II and thus the regression of cardiovascular hypertrophy and progression of renal damage.
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PMID:[Renaissance of the renin-angiotensin system in the pathogenesis and therapy of arterial hypertension]. 280 32

A patient with cirrhosis and coexistent hyporeninemic hypoaldosteronism secondary to diabetic nephropathy rapidly formed ascites despite marked reductions in plasma aldosterone concentration and urinary aldosterone excretion. To my knowledge, this association has not been previously reported. This case supports the concept that hyperaldosteronism is not a necessary component of the salt retention of advanced liver disease. Furthermore, it suggests that certain renal disorders should be considered in cases of cirrhosis and ascites with decreased plasma renin activity.
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PMID:Hyporeninemic hypoaldosteronism in a patient with cirrhosis and ascites. 353 21

Many diabetic patients will develop a nephropathy that will eventually result in end-stage renal failure. The early stage ("incipient") of diabetic nephropathy generally appears after 5 to 20 years of diabetes and is characterized by microalbuminuria (30 to 300 mg/day), which is only detectable by sensitive radio-immuno-enzymatic methods. When a frank proteinuria develops (> 500 mg/day), the glomerular filtration rate inexorably declines, resulting in terminal renal failure after several years. The onset of microalbuminuria or the elevation of blood pressure (above 120-140/80 mmHg) are predictive of a poor evolution and require appropriate preventive therapeutic interventions. These include an optimal control of hyperglycaemia, dietary proteins and salt restriction, and prescription of anti-hypertensive drugs, with a particular benefit ascribed to angio-tension converting enzyme inhibitors (and maybe to certain calcium channel blockers). These interventions have been proven efficient to prevent or slow down the evolution of diabetic nephropathy.
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PMID:[Renal complications of diabetes]. 748 Dec 38

Lithium is the best available marker of proximal tubular reabsorption of fluid. The first part of the present thesis reviews the background for the use of the lithium clearance (CLi) method. Micropuncture studies on proximal reabsorption of lithium, showed that CLi is a reasonably correct measure of end-proximal fluid delivery rate, even during osmotic diuresis. During severe salt restriction, distal reabsorption of lithium renders the CLi method inappropriate in animals, but this problem does probably not occur in humans. The major current issue is whether a quantitatively significant reabsorption of lithium occurs in the loop of Henle. Available evidence is in accord with the interpretation that it does not occur. The interpretation of results form CLi studies depends to a surprising degree on the investigators beliefs about renal physiology. In the evaluation of proximal tubular function, the relevant parameter is the absolute proximal reabsorption rate of fluid and sodium. In the evaluation of integrated distal tubular reabsorption of sodium, the relevant parameter is the fractional distal reabsorption rate of sodium. The fractional CLi does not give meaningful information, and calculated absolute distal reabsorption rate of sodium is inherently not suited to detect modest changes in distal reabsorption leading to large changes in sodium excretion. Results from the use of the CLi method in relation to diabetes are reviewed in the second section. Even in IDDM patients with early diabetic nephropathy, the proximal reabsorption rate is elevated, resulting in a normal CLi despite glomerular hyperfiltration. Overnight euglycemia did not change GFR in IDDM patients, but during maintained euglycemia, GFR was normalized. A few hours of hyperglycemia prevented the decline in GFR, whereas CLi was unchanged. Thus hyperglycemia produced changes in renal function similar to those observed previously, but the time-course of the effect of euglycemia on kidney function is delayed. Plasma levels of atrial natriuretic peptide, renin and glucagon were not importantly affected by plasma glucose. In NIDDM patients CLi was normal, despite slight hyperfiltration, although this observation must be confirmed in a study with larger sample size. Prompted by the clinical observation of a marked decline in the GFR induced by carbonic anhydrase inhibitors, we studied the renal effects of acetazolamide in a controlled study.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Lithium clearance in the evaluation of segmental renal tubular reabsorption of sodium and water in diabetes mellitus. 818 64

The effects of dietary salt restriction on the renin-angiotensin system, glomerular filtration rate (GFR), renal size, and albuminuria were assessed in streptozotocin diabetic rats. Two series of experiments were performed: one short-term with severe salt restriction and the second long-term with moderate salt restriction. The first studied the effect of a very-low-salt diet for 4 weeks on GFR, renal size, and plasma angiotensin II concentration in diabetic and control rats. Diabetic and control male Sprague-Dawley rats received either a very-low-salt (0.005% NaCl) or a normal-salt (0.4% NaCl) diet. Diabetes was associated with a 49% increase in GFR, a 34% increase in kidney weight, and an 85% reduction in plasma angiotensin II when compared with control rats (P < 0.001). Sodium restriction in diabetic rats reduced GFR, restored plasma angiotensin II to control values, and retarded kidney growth when compared with diabetic rats receiving a normal sodium diet. GFR correlated negatively with plasma angiotensin II (r = -0.65, P < 0.001) and positively with kidney weight (r = 0.66, P < 0.001). In the second experiment, serial measurements of albuminuria and GFR were performed in control, diabetic, and salt-restricted (0.05% NaCl) control and diabetic rats over 24 weeks. Albuminuria showed a continuous rise in the diabetic rats when compared with control rats. Salt restriction attenuated the increase in albuminuria over the whole study period as well as reducing blood pressure and kidney weight in the diabetic rats. In conclusion, sodium restriction was associated with a lower GFR and kidney weight after 4 weeks and reduced levels of albuminuria, kidney weight, and blood pressure after 24 weeks in diabetic rats. Salt restriction may have an important role in the prevention and treatment of diabetic nephropathy.
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PMID:Salt restriction reduces hyperfiltration, renal enlargement, and albuminuria in experimental diabetes. 897 Oct 91

Diabetic nephropathy tends to develop more readily in patients with a family history of hypertension and/or disturbances in sodium transport across the plasma membrane. This prompted us to study the renal effects of diabetes mellitus in a rat strain which is predisposed to develop salt-sensitive hypertension, the Dahl salt-sensitive rat. Diabetes is associated with several aberrations in the renal handling of sodium, such as elevation of tubular Na+, K+ATPase activity. This effect was more pronounced in Dahl salt-sensitive than in Dahl salt-resistant rats. Severe renal lesions, characteristic of the advanced phase of diabetic nephropathy are very rarely observed in rats with streptozotocin diabetes. However, 2 months after induction of diabetes, the Dahl salt-sensitive rats had morphological signs of advanced glomerular disease. The urinary albumin concentration was very high, but did not correlate with the blood pressure. Non-diabetic Dahl salt-sensitive rats as well as Dahl salt-resistant diabetic and non-diabetic rats had little or no signs of glomerular disease and consistently very low urinary albumin concentrations.
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PMID:Rapid development of glomerulosclerosis in diabetic Dahl salt-sensitive rats. 911 12


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