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)

Differential solute clearances were used to examine the effects of a 90-day course of enalapril on glomerular barrier function in 16 proteinuric patients with diabetic glomerulopathy. By day 90, plasma renin and prorenin became elevated, and arterial pressure declined. Transglomerular passage of dextrans of broad size distribution (radii 28-60 A) was lowered significantly. In a subset of 8 patients, withdrawal of enalapril was followed after an additional 30 days by a return of renin levels and arterial pressure to pretreatment levels. The dextran-sieving profile also returned to baseline, becoming uniformly elevated above treated day-90 levels. A theoretical analysis of the serial dextran-sieving profiles indicated that enalapril shifted glomerular pore size distribution to smaller size. These changes in barrier size selectivity were associated with a reduction in fractional albumin and IgG clearances during enalapril therapy and a subsequent rise in these quantities after its withdrawal; urinary protein excretion rate tended to vary in parallel. We conclude that inhibition of converting enzyme in humans with established diabetic glomerulopathy diminishes glomerular permeability to proteins by enhancing barrier size selectivity. Because neither enalapril therapy nor its withdrawal influenced the glomerular filtration or renal plasma flow rates significantly, we propose that the primary action of enalapril may be to modulate the intrinsic membrane properties of the glomerular barrier.
Diabetes 1990 Jan
PMID:Effects of converting-enzyme inhibition on barrier function in diabetic glomerulopathy. 169 74

Cross-linking of cell matrix components by nonenzymatic glycosylation may contribute to diabetic glomerulopathy. We examined the effects of modification of matrix by nonenzymatic glycosylation on mesangial cell function. Matrix was generated by growing mesangial cells in tissue culture for 2 wk and removing the cells with a detergent cell-lysis solution. By indirect immunofluorescence and Northern-blot analysis, the remaining matrix contained laminin, fibronectin, and collagens type I and IV. The matrix was modified by incubation for 24 h with 50 mM glycolaldehyde, a highly reactive cross-linking nonenzymatic glycosylation product, or for 2 wk with 200 mM glucose-6-phosphate (G6P). Modification was carried out with or without equimolar aminoguanidine, an inhibitor of cross-link formation. Nonenzymatic glycosylation of the matrix by glycolaldehyde or G6P was confirmed by fluorometry and [14C]G6P incorporation and was prevented by aminoguanidine. [3H]thymidine incorporation for 24 h by mesangial cells plated onto unmodified or modified matrix was then performed. Modification of matrix had no effect on attachment of mesangial cells, determined 4 h after plating. Nonenzymatic glycosylation of matrix by glycolaldehyde or G6P significantly inhibited thymidine incorporation by mesangial cells. This effect was partially reversible by aminoguanidine. Aminoguanidine-modified matrix had no effect on thymidine incorporation. Thymidine-incorporation results were confirmed by direct cell counting. We conclude that modification of matrix by nonenzymatic glycosylation influences growth of mesangial cells, which could contribute to the mesangial abnormalities of diabetic glomerulopathy.
Diabetes 1991 May
PMID:Effects of nonenzymatic glycosylation of mesangial matrix on proliferation of mesangial cells. 170 34

Diabetic nephropathy, clinically defined by overt albuminuria, hypertension and declining GFR, affects 25-35% of IDDM patients. The risk of nephropathy peaks during the second decade of IDDM and declines thereafter, suggesting that only a subset of IDDM patients is at risk for nephropathy. A role for hypertension in the progression of established renal damage in IDDM is now accepted; however the role of hypertension in the genesis of diabetic nephropathy is not yet clear. Mesangial expansion is a characteristic lesion of diabetic nephropathology and correlates with renal function. Functional studies are not indicative of underlying renal pathology except relatively late, when glomerular injury is advanced. Microalbuminuria in the 'predictive' range (greater than 30 micrograms/min) and associated with hypertension and/or declining GFR is a marker of established diabetic glomerulopathy. Only carefully designed longitudinal studies of renal morphology and function with accurate blood pressure monitoring beginning early in the course of IDDM will clarify the relationships between blood pressure and renal damage in IDDM. In NIDDM the frequent presence of non-diabetic renal lesions, of hypertension at or before the onset of diabetes, and the relative paucity of clinical-pathological correlations currently make it difficult to understand the role of hypertension in the genesis and progression of nephropathy. Again, longitudinal studies of blood pressure and renal structure and function are required in NIDDM patients. Finally, animal models of hypertension and diabetes may aid progress in these areas.
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PMID:Hypertension and diabetic renal disease. 179 13

Glomerular lesions in WBN/Kob male rats with spontaneous diabetes were examined histopathologically. The glomerulopathy caused by diabetes was compared with lesions in chronic progressive nephropathy of non-diabetic SD and F344 male aged rats. Diffuse and global thickening of the mesangial area was observed only in WBN/Kob rats and showed a statistically significant correlation with serum glucose concentrations. Therefore, it suggested that the mesangial thickening was a result of hyperglycaemia. Fibrin cap-like lesions were seen in both WBN/Kob and non-diabetic SD or F344 male rats. The severity of these lesions was closely related to that of chronic progressive nephropathy and, therefore, the fibrin cap-like lesions were considered to be due to the chronic progressive nephropathy.
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PMID:Glomerular lesions in spontaneously occurring diabetic WBN/Kob rats. 187 82

We have investigated 975 different grazing sections of vessels in kidney preparations of 20 rats of the Wistar strain. Half of these genetically identical animals had an insulin-deficiency diabetes induced by injection of streptozocin. The kidneys were removed for investigation after 2 and 12 weeks duration of diabetes. The vessel cross-section, wall, lumen and endothelial surface area were determined in renal arteries, arterioles and preglomerular afferent arterioles in a blind experiment. Statistically detecteable changes were found in the diabetic vessels in the early stage of the diabetes. Preglomerular afferent arterioles showed a highly significant and increasing lumen dilatation commencing after 2 weeks. Diabetic arteries and arterioles developed narrower lumina. A significant thickening of the endothelium took place at the same time in both vessel types. All three vessel regions became smaller and had thinner walls than healthy vessels as the diabetes progressed. The findings on the afferent vessels indicate that haemodynamic effects on the glomerulus are to be expected. Familial diabetic gloermulopathy begins with a reversible hyperfiltration. However, the mechanism has not been clarified in the context of the diabetic metabolic disorder, and this change is probably the haemodynamic consequence of the substantial dilatation of the preglomerular afferent arterioles. With their renin-positive segment, these arterioles are the centre of intrarenal regulation. The increase of the capillary glomerular pressure associated with the dilatation of the preglomerular afferent arterioles is a crucial factor in the development of diabetic glomerulopathy.
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PMID:Morphometric investigations on intrarenal vessels of streptozotocin-diabetic rats. 192 64

The etiology of diabetic glomerulopathy appears to be related, at least in part, to the degree of hyperglycemia, the resultant nonenzymatic glycosylation of proteins, and the eventual formation of advanced glycosylation end products in long-lived structural proteins. To investigate the relationship between the glomerular basement membrane (GBM) changes of diabetic nephropathy and the formation of advanced glycosylation end products, we studied control rats, diabetic rats, and control and diabetic rats who received aminoguanidine, a compound that pharmacologically inhibits formation of advanced glycosylation end products. After 9 months, rat weight was smaller and kidney weight larger in both diabetic groups compared with both control groups. GBM width was increased in the diabetic group compared with the control group. Aminoguanidine administration to diabetic rats ameliorated this increase in GBM. Thus, aminoguanidine administration from the onset of experimental diabetes prevented the widening of the GBM that is typical of diabetes.
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PMID:Prevention of glomerular basement membrane thickening by aminoguanidine in experimental diabetes mellitus. 194 26

The pathophysiological connections between insulin resistance, hypertension and type 2 diabetes are discussed in this review article. Increased blood pressure levels are often found in type 2 diabetic patients long before the diabetes itself is diagnosed. By contrast, in type 1 diabetes hypertension is predominantly the consequence of diabetic glomerulopathy. Non-pharmacological strategies should be favoured in the treatment of hypertension in type 2 diabetic patients before specific pharmacological intervention is started. Antihypertensive treatment with beta-blocking agents and diuretics is criticized by many experts in the field of metabolic disorders, since these drugs induce a deterioration of glycaemic control and lipid metabolism in diabetic patients. Since calcium channel blockers, ACE inhibitors and alpha 1-specific blocking agents have no influence on metabolism, these drugs are recommended for the antihypertensive treatment of diabetic patients. Further studies should be undertaken to clarify, whether ACE-inhibitors have a specific nephroprotective effect. Since most type 2 diabetic patients do not develop diabetic nephropathy, a possible nephroprotective effect of ACE inhibitors is only relevant to the antihypertensive treatment of type 1 diabetic patients.
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PMID:[Hypertension, insulin resistance and diabetes mellitus: pathophysiological interactions and therapeutic consequences]. 198 Jul 67

The plasma factors influencing PGI2-like activity in 19 patients with diabetes mellitus (Dm) and 17 control subjects were studied by comparing the signs of retinal versus glomerular angiopathy. The plasma PGI2-supporting activity (PSA) was lower in 15 Dm cases than in the controls. Inhibitory activity against PGI2 production was detected in 6 patients. When more serious retinopathy was associated with glomerulopathy, a significantly lower level of PSA was observed than in patients with mild retinopathy without glomerular disease. The plasma concentrations of total and LDL cholesterol were significantly higher, while the level of HDL cholesterol was lower than in the controls. There was a positive correlation between PSA and HDL cholesterol values and a negative correlation between PSA and LDL cholesterol levels, which is related to the inhibitory effect of LDL and the protective role of HDL in PGI2 synthesis.
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PMID:[Prostacyclin-like activity modifying plasma factors in diabetic microangiopathy]. 211 54

Coexistent renal pathology with diabetic glomerulosclerosis was found in 38 of 136 (28%) consecutive renal biopsies performed primarily for proteinuria in individuals with diabetes mellitus. The histological lesions found were glomerulonephritis (14), focal tubulointerstitial disease (23), and amyloidosis (1). Significant microscopic haematuria was present in 66% of all patients and did not help to distinguish non-diabetic disease. The severity of diffuse diabetic glomerular disease was independently associated with duration of diabetes, raised plasma creatinine, the presence of hypertension, clinical retinopathy and neuropathy, but not with type of diabetes, degree of proteinuria or glycosylated haemoglobin at the time of biopsy. Diffuse interstitial fibrosis was related to the severity of glomerular disease and, if severe, also with a significantly (p less than 0.01) higher plasma creatinine. Coexisting renal disease was found to be associated with a significantly higher plasma creatinine (p less than 0.01) independent of the severity of diabetic glomerulopathy. Coexistent pathology is a not uncommon finding in renal biopsies from diabetic patients with proteinuria. These lesions and their underlying causes may not only influence the renal function and natural history of renal disease in diabetic individuals, but may also determine the response of proteinuria to therapy.
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PMID:A clinical-histological study of individuals with diabetes mellitus and proteinuria. 213 92

At present the pathogenesis of diabetic nephropathy remains unresolved. Clearly lack of insulin, with its associated disorders of carbohydrate, protein, and/or lipid metabolism, initiates the process which eventually leads to the characteristic histologic picture of diabetic nephropathy. The disturbance in cellular metabolism per se could directly injure the kidney by altering the energy needs of the cell or by leading to the accumulation of cellular toxins (ie, polyols) or by causing the deficiency of key cellular metabolites (ie, myoinositol). Elevation of the plasma glucose concentration enhances the glycosylation of proteins, which in turn can lead to glomerular basement membrane thickening, loss of charge selectivity, and direct cellular damage. The multiple disturbances in intermediary metabolism are associated with increased levels of and/or enhanced sensitivity to a variety of growth factors, including IGF-I and angiotensin, and this could lead to glomerular hypertrophy. An increase in the filtered load and subsequent reabsorption of electrolytes and metabolites also could contribute to renal hypertrophy. In all animal models of nephropathy, including diabetes, glomerular hypertrophy has been shown to be the best correlate of glomerular sclerosis, proteinuria, and progressive renal deterioration. The potential mechanisms by which glomerular hypertrophy can lead to renal histologic damage were discussed previously. By increasing the luminal diameter, glomerular hypertrophy also would be expected to augment wall tension and thereby increase intraglomerular pressure. Derangements in cellular metabolism or altered sensitivity to angiotensin also can directly elevate the intraglomerular pressure and lead to structural renal damage. In this schema, elevated intraglomerular pressure is but one of many pathogenic factors that contribute to the development of diabetic glomerulopathy and albuminuria. The precise role of increased glomerular pressure in the evolution of diabetic nephropathy remains uncertain at present. In rats, severe diabetic nephropathy can occur without an increase in Pgc, while in humans, hyperfiltration does not appear to be a predictor of proteinuria and renal dysfunction. Lastly, it is likely that a variety of other factors, including the coagulation system, plasma/cell lipid levels, prostaglandins, etc, also play a role in the pathogenesis of diabetic nephropathy. According to the outline presented in Figure 1, it is unlikely that any single factor will be sufficient to explain the development of diabetic glomerulosclerosis. Ultimately, the origin of diabetic nephropathy in IDDM must be traced to insulin lack, with its associated derangements in cellular metabolism. Therefore, the importance of tight glucose control should not be underemphasized.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Hyperfiltration and diabetic nephropathy: is it the beginning? Or is it the end? 219 Feb 80


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