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

Glomerular hyperfiltration is thought to play an important role in the genesis of diabetic nephropathy. While hyperfiltration is well documented in early type I diabetes, the evidence for hyperfiltration in type II diabetes is conflicting. We investigated 16 nonproteinuric patients with recently diagnosed type II diabetes. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured as inulin clearance (CIN) and p-aminohippuric acid clearance (CPAH) using a constant infusion technique. Lean body mass was measured by densitometry (weighing under water). Renal hemodynamics were also measured in 31 healthy volunteers and six obese nondiabetic individuals. Median GFR in diabetics (133 mL/min/1.73 m2; range, 95 to 165) was significantly (P < 0.01) higher than in obese nondiabetic controls (median, 118; range, 95 to 139). Elevated GFR (ie, > 95th percentile of nonobese healthy controls) was found in 44% of patients. When GFR was factored for lean body mass, it was elevated in 50%. GFR did not correlate with fasting glucose, hemoglobin A1C (HbA1C), insulin-like growth factors, IGF-1 and IGF-2, or somatomedin-binding protein (SMBP). The findings document that hyperfiltration is common in recent-onset type II diabetics.
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PMID:Renal hemodynamics in recent-onset type II diabetes. 141 1

Angiotensin-converting enzyme (ACE) inhibitors decrease albuminuria in patients with diabetic nephropathy. To study the change in albuminuria in relation to changes in systemic and renal hemodynamics, nine normotensive patients with type 1 (insulin-dependent) diabetes mellitus and persistent proteinuria were given a single oral dose of 25 mg of the ACE inhibitor captopril. Blood pressure, glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and albumin excretion rate (AER) were measured in two periods of 40 minutes before and in four periods of 40 minutes after administration of captopril. A constant water diuresis was maintained. Blood pressure did not decrease significantly (130/79 +/- 4/3 v 124/74 +/- 4/3 mm Hg; mean +/- SEM), median AER decreased from 403 (interquartile range [IQR], 812) micrograms/min to 333 (707) micrograms/min (P < 0.01). GFR did not change (123 +/- 13 v 117 +/- 14 mL/min), but ERPF increased significantly from 609 +/- 56 to 714 +/- 55 mL/min (P < 0.01). Consequently, the filtration fraction (FF; quotient of GFR and ERPF) decreased from 0.20 +/- 0.014 to 0.17 +/- 0.014 (P < 0.01). A strong correlation was found between the decrease of AER and the decrease of FF (rs = 0.75; P < 0.02). No correlation was found between the decrease in AER and changes in GFR or blood pressure. In the normotensive patient with diabetic nephropathy, captopril causes an acute reduction of AER, which is probably mediated by a lowering of the intraglomerular pressure.
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PMID:Captopril acutely lowers albuminuria in normotensive patients with diabetic nephropathy. 146 82

Proton magnetic resonance imaging was performed on rats before induction of diabetes with streptozotocin (STZ) and at 2 and 12 days postinduction. Images revealed an increase in maximal longitudinal and axial dimensions of the kidneys at 2 days and a further increase at 12 days. Similarly, an increase in the size of the remaining kidney was seen in a rat which underwent uninephrectomy as a positive control. Two major differences were observed between the kidney undergoing compensatory hypertrophy and those developing diabetic nephropathy: (i) Expansion of the renal vasculature was seen only in images of the diabetic rat; (ii) A loss in conspicuity of the normal corticomedullary junction was seen in the T2-weighted images of the diabetic rat but not in the uninephrectomized rat. Histologic examination revealed that the medulla increased to a size greater than the cortex during diabetic nephropathy whereas the medullary volume was less than that of the cortex during compensatory hypertrophy. In vitro T1 relaxation times in cortex, outer medulla and inner medulla of kidneys from control rats were measured and compared with the same respective regions in diabetic rats. When these values were correlated with tissue water content, a linear increase in relaxation rate versus percent water content from cortex to inner medulla was found in the control kidneys, but this correlation was absent in diabetic nephropathy. These studies demonstrate that MRI is an effective noninvasive tool for studying the course of renal hypertrophy and hydration changes in the development of renal disease in STZ-induced diabetes in the rat.
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PMID:Magnetic resonance imaging (MRI) and pathophysiology of the rat kidney in streptozotocin-induced diabetes. 164 77

We evaluated the renal and hormonal responses to volume expansion induced by water immersion in subjects with diabetic nephropathy (n = 12) and in healthy control subjects (n = 9). Immersion induced similar average increments in sodium excretion (+/- 223 vs. 176 mumol/min) and comparable decrements in renovascular resistance (RVR; -15 vs. -16 U). However, whereas the control subjects responded uniformly, the response among diabetic subjects was highly variable, with a subset of patients exhibiting paradoxical antinatriuresis and vasoconstriction. Immersion was associated with marked elevation of atrial natriuretic peptide (ANP) in plasma of diabetic versus control subjects (61 +/- 9 vs. 19 +/- 2 pM, respectively; P less than 0.001). Yet for each picomolar increment in plasma ANP during immersion, the corresponding increases in urinary excretion of cyclic guanosine monophosphate (26 vs. 279 pmol/min) and sodium (9 vs. 47 mumol/min) and the reciprocal lowering of RVR (0.7 vs. 1.9 U) were blunted in the diabetic versus control group. Volume contraction in the postimmersion period was associated with disproportionate antinatriuresis and renal vasoconstriction in the diabetic group, despite a persistent elevation of ANP (29 +/- 2 vs. 16 +/- 2 pM, P less than 0.01). We propose that renal insensitivity to ANP in diabetic nephropathy could contribute to altered vasoreactivity and abnormal excretory responsiveness to changing plasma volume. Blunted natriuresis in response to ANP release and enhanced sodium retention during volume contraction could account for the expanded extracellular fluid volume that has consistently been reported to accompany the development of diabetic nephropathy.
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PMID:Atrial natriuretic peptide and response to changing plasma volume in diabetic nephropathy. 164 96

Several lines of evidence suggest that hypertension is a contributing factor to diabetic nephropathy, a major cause of mortality in diabetes mellitus patients. The present study tested the hypotheses (1) that insulin dependent diabetes (IDD) causes hypertension, and (2) that simultaneous hypertension and IDD causes greater renal damage than would be expected from the independent contributions of each disease. IDD was induced by injection of streptozotocin (STZ, 65 mg/kg i.p.) into male Wistar rats, causing severe hyperglycaemia within 4 days. Seven days after the STZ treatment, hypertension was initiated by subcutaneous implantation of deoxycorticosterone acetate and administration of 1% saline in the drinking water (DOCA-NaCl). IDD rats not receiving DOCA-NaCl displayed a small elevation of blood pressure one week after STZ treatment, but thereafter displayed significant hypotension. The IDD rats receiving DOCA-NaCl displayed elevated systolic arterial pressure throughout the study, but by the end of the experiment, their mean systolic arterial pressure was significantly lower than that of the rats treated with DOCA-NaCl alone. Only the IDD/DOCA-NaCl rats displayed significant signs of renal dysfunction, i.e. greatly increased proteinuria and morphological renal damage, including marked distension of distal tubules and occasional casts. No other group displayed these abnormalities.
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PMID:Effects of simultaneous diabetes and hypertension in an insulin dependent diabetic model. 176 11

To study the role of laminin in the rat mesangial cell attachment, cell adhesion to laminin-coated dishes was assayed by adding various amounts of a pentapeptide (YIGSR). YIGSR (20-100 micrograms/mL) inhibited the cell attachment to laminin-coated dishes. Mesangial laminin B2 messenger RNA (mRNA) levels were attenuated during exposure to 30 mM glucose or high osmolarity achieved by the addition of 25 mM choline chloride to 5 mM glucose (310 mOsm/kg H2O) for 3 hours. These results suggest that laminin, which may have a physiologic role in mesangial cell attachment, is produced in mesangial cells, and that the decrease of laminin B2 mRNA during hyperglycemia or exposure to high osmolarity may have some pathophysiologic significance in the development of diabetic nephropathy.
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PMID:High glucose concentration suppresses mesangial laminin B2 gene expression. 177 15

Vanadate has been previously shown to normalize blood glucose in streptozotocin-induced diabetic (STZ-DM) rats. The effect of a previously studied dose of vanadate (0.8 mg/ml) in drinking water on blood glucose, renal hypertrophy, and whole kidney polyol accumulation was studied in STZ-DM rats. Rats with diabetes of 5 weeks duration had higher blood glucose, greater urinary output, higher kidney weight, lower body weight, and higher kidney to body weight ratios than controls. Whole kidney sorbitol concentrations were significantly increased in diabetes but myo-inositol levels were unchanged vs control animals. After four weeks of oral vanadate treatment, blood glucose, urine volume, and kidney weights were similar to control values. Kidney to body weight ratios fell below that of the STZ-DM animals, but because body weights remained decreased, the kidney to body weight ratios were not normalized. Renal sorbitol levels returned to control values and renal myo-inositol levels remained unchanged in STZ-DM and normal animals treated with vanadate. These results provide evidence that vanadate therapy may result in regression of the hypertrophy and polyol accumulation characteristic of diabetic nephropathy in STZ-DM rats. This effect is most likely due to normalization of blood glucose by the insulin-mimetic activity of vanadate treatment.
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PMID:Effect of vanadate on renal hypertrophy and sorbitol accumulation in streptozotocin induced diabetes in rats. 187 50

The renal effects of diabetes mellitus and cadmium (Cd), separately or in combination, were investigated in unilaterally nephrectomized female Sprague-Dawley rats. Diabetes was induced by injection of streptozotocin and Cd was administered in drinking water at a concentration of 100 p.p.m. for 2.5 months. Cd did not affect the reduction in glomerular filtration rate or the rise in beta 2-microglobulinuria caused by diabetes. By contrast, the effect of diabetes on the urinary excretion of albumin, transferrin or IgG was greatly enhanced by concomitant exposure to Cd. This interaction occurred at Cd levels in the renal cortex which are very similar to those found in the general population of industrialized countries. These observations, in agreement with the results of a recent epidemiological study, suggest that Cd polluting the environment might potentiate the development of diabetic nephropathy.
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PMID:Potentiation of diabetic glomerulopathy in uninephrectomized rats subchronically exposed to cadmium. 189 6

Contrasting results have been reported regarding the prevalence of hypertension in insulin-dependent diabetes mellitus (IDDM), showing a slightly higher or normal percentage of IDDM patients with elevated blood pressure levels than in the general population. Most of the cross-sectional and prospective studies on the prevalence of hypertension in IDDM show an association between microalbuminuria and elevated blood pressure levels. However, it is not clear whether hypertension is simply secondary to kidney damage or whether hypertension occurs with or even before the development of impaired kidney function. Patients with IDDM have a higher exchangeable body Na+ pool. Na+ retention in IDDM is accounted for by several metabolic and hormonal abnormalities such as hyperglycemia, hyperketonemia, hyperinsulinemia, altered secretion, and resistance to atrial natriuretic peptide. High blood pressure appears to be dependent, at least at some phase, on expansion of extracellular fluid volume as a consequence of defects in the renal secretion of Na+ and water. On the other hand, a tendency toward Na+ retention characterizes all patients with IDDM, whereas hypertension develops only in a subgroup of diabetic patients. One possible explanation for these findings is that a genetic predisposition plays a role in creating susceptibility to hypertension and perhaps to diabetic nephropathy independent of diabetes, even if Na+ retention can further deteriorate this susceptibility to hypertension. With regard to this issue, it has recently been suggested that the risk of kidney disease in patients with IDDM is associated with a genetic predisposition to hypertension. Furthermore, diabetic nephropathy occurs in familial clusters, because diabetic siblings of nephropathic diabetic patients show a higher frequency of diabetic nephropathy than the diabetic siblings of nonnephropathic diabetic patients. One of the possible genetic markers that could be useful to identify the diabetic patients with susceptibility to hypertension and diabetic nephropathy is the Na+(-)Li+ countertransport activity in erythrocytes.
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PMID:Insulin-dependent diabetes mellitus and hypertension. 204 36

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


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