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)

The mechanism of glomerular infiltration of monocytes remains unknown in diabetic nephropathy. We examined the effect of a high glucose concentration on monocyte chemotactic peptide 1 (MCP-1) expression in human mesangial cells (MCs) by using enzyme-linked immunosorbent assay and reverse transcription coupled with polymerase chain reaction (PCR). More than a 50% increase in the MCP-1 protein production was observed in MCs cultured in high-glucose medium (450 mg/dl) as compared to normal glucose (100 mg/dl; 1,496 +/- 75 vs. 966 +/- 15 pg/ml after 24 h, 1,910 +/- 93 vs. 1,250 +/- 55 pg/ml after 48 h). Semiquantitative PCR showed that phorbol myristate acetate (100 nM) increased the ratio of PCR products for MCP-1 to housekeeping gene glyceraldehyde-3-phosphate dehydrogenase on densitometric results at 24 h by 2.7-fold, which was prevented by calphostin C (200 nM) pretreatment. High glucose increased the ratio by 3-fold as compared to normal glucose at 24 h (0.72 +/- 0.11 vs. 0.24 +/- 0.01). This was also suppressed by calphostin C pretreatment. These findings demonstrate that high glucose can directly increase MCP-1 expression in MCs, which may contribute to monocyte infiltration in diabetic nephropathy, and this is regulated by protein kinase C.
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PMID:A high glucose concentration stimulates the expression of monocyte chemotactic peptide 1 in human mesangial cells. 960 59

The factors responsible for variable susceptibility to diabetic nephropathy are not clear. According to the non-enzymatic glycation hypothesis, diabetes-related tissue damage occurs due to a complex mixture of toxic products, including alpha-oxoaldehydes, which are inherently toxic as well as serving as precursors for advanced glycation end-products. Protective mechanisms exist to control this unavoidable glycation, and these are determined by genetic or environmental factors that can regulate the concentrations of the reactive sugars or end-products. In diabetes these protective mechanisms become more important, since glycation stress increases, and less efficient defence systems against this stress could lead to diabetic complications. Some of these enzymatic control mechanisms, including those that regulate alpha-oxoaldehydes, have been identified. We have observed significant increases in production of the alpha-oxoaldehydes methylglyoxal and 3-deoxyglucosone in three human populations with biopsy-proven progression of nephropathy. The increase in methylglyoxal could be secondary to defects in downstream glycolytic enzymes (such as glyceraldehyde-3-phosphate dehydrogenase) that regulate its production, or in detoxification mechanisms such as glyoxalase. Other mechanisms, however, appear to be responsible for the observed increase in 3-deoxyglucosone levels. We present results of our studies on the mechanisms responsible for variable production of alpha-oxoaldehydes by measuring the activity and characteristics of these enzymes in cells from complication-prone and -resistant diabetic patients. New therapeutic interventions designed to control these endogenous mechanisms could potentially enhance protection against excessive glycation and prevent or reverse complications of long-term diabetes.
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PMID:Alpha-oxoaldehyde metabolism and diabetic complications. 1464 Oct 63

Defective intracellular antioxidant enzyme production (IAP) has been demonstrated in adults with diabetic nephropathy. To evaluate the effects on IAP of vitamin E administration in adolescents with type 1 diabetes and early signs of microangiopathy, 12 adolescents (aged 11-21 y; diabetes duration 10-18) were studied. Eight had retinopathy [background (four), preproliferative (three), or proliferative (one)], four had persistent microalbuminuria, and seven had both. Skin fibroblasts were obtained by biopsies and cultured in Dulbecco's modified Eagle's medium. CuZn superoxide dismutase (SOD), MnSOD, catalase (CAT), and glutathione-peroxidase (GPX) activity and mRNA expression were measured before and after 3 mo of synthetic vitamin E supplementation (600 mg twice daily); on both occasions, IAP was evaluated at different ex vivo glucose concentrations (5 and 22 mM). Ten adolescents with type 1 diabetes (aged 12-20 y) without angiopathy and eight healthy volunteers (aged 15-22 y) participated as control subjects. Vitamin E serum levels were measured throughout the study. In normal glucose concentrations, CuZnSOD, MnSOD, CAT, and GPX activity and mRNA expression were not different among the groups. In high glucose, CuZnSOD activity and mRNA increased similarly in all groups [angiopathics: 0.96 +/- 0.30 U/mg protein; 9.9 +/- 3.2 mRNA/glyceraldehyde-3-phosphate dehydrogenase). CAT and GPX activity and mRNA did not increase in high glucose only in adolescents with angiopathy (0.35 +/- 0.09; 4.2 +/- 0.1 and 0.52 +/- 0.14; 2.4 +/- 0.9, respectively). MnSOD did not change in any group. Vitamin E supplementation had no effect on any enzymatic activity and mRNA in both normal and hyperglycemic conditions. Adolescents with early signs of diabetic angiopathy have defective IAP and activity, which are not modified by vitamin E.
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PMID:Effects of vitamin E supplementation on intracellular antioxidant enzyme production in adolescents with type 1 diabetes and early microangiopathy. 1534 73

Dicarbonyl and oxidative stress may play important roles in the development of diabetes complications, and their response to hyperglycemia could determine individual susceptibility to diabetic nephropathy. This study examines the relationship of methylglyoxal, 3-deoxyglucosone (3DG), and oxidative stress levels to diabetic nephropathy risk in three populations with diabetes. All subjects in the Overt Nephropathy Progressor/Nonprogressor (ONPN) cohort (n = 14), the Natural History of Diabetic Nephropathy study (NHS) cohort (n = 110), and the Pima Indian cohort (n = 45) were evaluated for clinical nephropathy, while renal structural measures of fractional mesangial volume [Vv(Mes/glom)] and glomerular basement membrane (GBM) width were determined by electron microscopy morphometry in the NHS and Pima Indian cohorts. Methylglyoxal and 3DG levels reflected dicarbonyl stress, while reduced glutathione (GSH) and urine 8-isoprostane (8-IP) measured oxidative stress. Cross-sectional measures of methylglyoxal production by red blood cells incubated in 30 mmol/l glucose were increased in nephropathy progressors relative to nonprogressors in the ONPN (P = 0.027) and also reflected 5-year GBM thickening in the NHS cohort (P = 0.04). As nephropathy progressed in the NHS cohort, in vivo levels of methylglyoxal (P = 0.036), 3DG (P = 0.004), and oxidative stress (8-IP, P = 0.007 and GSH, P = 0.005) were seen, while increased methylglyoxal levels occurred as nephropathy progressed (P = 0.0016) in the type 2 Pima Indian cohort. Decreased glyceraldehyde-3-phosphate dehydrogenase activity also correlated with increased methylglyoxal levels (P = 0.003) in the NHS cohort. In conclusion, progression of diabetic nephropathy is significantly related to elevated dicarbonyl stress and possibly related to oxidative stress in three separate populations, suggesting that these factors play a role in determining individual susceptibility.
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PMID:Susceptibility to diabetic nephropathy is related to dicarbonyl and oxidative stress. 1624 55