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Elevated Glucose (elevated + glucose)
Selected AbstractsAntioxidant Protection Mechanisms And Arachidonic Acid Synthesis Are Altered In Schwann Cells Grown In Elevated GlucoseJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2000C Miinea Accumulating evidence points to oxidative stress as an important factor in the onset of diabetic neuropathy. We have investigated the status of antioxidant protection mechanisms in immortalized rat Schwann cells cultured in high (30 and 50 mM) concentrations of glucose. As compared to growth in 5 mM glucose, the cells contained 40% less reduced glutathione (n =8, p < 0.01). Total superoxide dismutase activity was diminished by more than 50% (n=3; p < 0.001), whereas catalase activity was unchanged. The cellular NADH/NAD+ ratio was progressively increased with increasing medium glucose concentrations. Our previous findings have established that upon exposure of cultured cells to elevated glucose, the proportions of arachidonic acid-containing molecular species (ACMS) in phospholipids are decreased in a pattern similar to alterations exhibited by diabetic nerve. To examine whether biosynthesis of arachidonic acid might be perturbed, confluent cells maintained in either high or low glucose were incubated with either [14C]linoleic acid (18:2) or [14C]dihomo-,-linolenic acid (20:3) and radioactivity incorporated into molecular species of major phospholipid classes was measured. The incorporation of 18:2 either as unchanged fatty acid or into ACMS did not differ as a function of glucose concentration. Negligible labeled 18:3 or 20:3 molecular species were detected. In contrast, the uptake of 20:3 into 18:1/20:4 and 16:0/20:4 phosphatidylcholine and 18:1/20:4 phosphatidylethanolamine, but not into 20:3-containing molecular species, was significantly reduced in cells cultured in 30 mM glucose. These data imply that ,5 desaturase activity is decreased in cells exposed to elevated glucose. This reduced enzyme activity could adversely affect polyunsaturated fatty acid metabolism and might arise as a consequence of impaired scavenging of reactive oxygen species. (Supported by NIH grant DK30577) [source] Protein kinase C and the development of diabetic vascular complicationsDIABETIC MEDICINE, Issue 12 2001K. J. Way Abstract Hyperglycemic control in diabetes is key to preventing the development and progression of vascular complications such as retinopathy, nephropathy and neuropathy. Increased activation of the diacylglycerol (DAG)-protein kinase C (PKC) signal transduction pathway has been identified in vascular tissues from diabetic animals, and in vascular cells exposed to elevated glucose. Vascular abnormalities associated with glucose-induced PKC activation leading to increased synthesis of DAG include altered vascular blood flow, extracellular matrix deposition, basement membrane thickening, increased permeability and neovascularization. Preferential activation of the PKC, isoform by elevated glucose is reported to occur in a variety of vascular tissues. This has lead to the development of LY333531, a PKC, isoform specific inhibitor, which has shown potential in animal models to be an orally effective and nontoxic therapy able to produce significant improvements in diabetic retinopathy, nephropathy, neuropathy and cardiac dysfunction. Additionally, the antioxidant vitamin E has been identified as an inhibitor of the DAG-PKC pathway, and shows promise in reducing vascular complications in animal models of diabetes. Given the overwhelming evidence indicating a role for PKC activation in contributing to the development of diabetic vascular complications, pharmacological therapies that can modulate this pathway, particularly with PKC isoform selectivity, show great promise for treatment of vascular complications, even in the presence of hyperglycemia. Diabet. Med. 18, 945,959 (2001) [source] Altered arachidonic acid biosynthesis and antioxidant protection mechanisms in Schwann cells grown in elevated glucoseJOURNAL OF NEUROCHEMISTRY, Issue 6 2002Cristinel Mîinea Abstract In cultured Schwann cells, elevated glucose induces alterations in arachidonic acid metabolism that cause a decrease in the content of glycerophospholipid arachidonoyl-containing molecular species (ACMS). This could result from decreased de novo arachidonic acid biosynthesis, or increased arachidonic acid release from phospholipids. Incorporation of radioactive 8,11,14-eicosatrienoic acid into ACMS was lower for cells grown in 30 mm versus 5 mm glucose, consistent with a decrease in ,5 desaturase activity. However, neither basal arachidonic acid release from prelabeled cells nor stimulated generation of arachidonic acid in the presence of the reacylation inhibitor, thimerosal, the phosphotyrosine phosphatase inhibitor, bipyridyl peroxovanadium, or both together, were altered by varying the glucose concentrations, indicating that arachidonic acid turnover did not contribute to ACMS depletion. Free cytosolic NAD+/NADH decreased, whereas NADP+/NADPH remained unchanged for cells grown in elevated glucose, implying that decreased desaturase activity is a result of metabolic changes other than cofactor availability. Schwann cells in elevated glucose were susceptible to oxidative stress, as shown by increased malondialdehyde, depleted glutathione levels, and reduced cytosolic superoxide dismutase activity. Glutathione-altering compounds had no effect on ACMS levels, in contrast to N -acetylcysteine and ,-lipoic acid, which partly corrected ACMS depletion in phosphatidylcholine. These findings suggest that in the Schwann cell cultures, a high glucose level elicits oxidative stress and weakens antioxidant protection mechanisms which could decrease arachidonic acid biosynthesis and that this deficit can be partly corrected by treatment with exogenous antioxidants. [source] Blood Glucose Level, Alcohol Heavy Drinking, and Alcohol Craving During Treatment for Alcohol Dependence: Results From the Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence (COMBINE) StudyALCOHOLISM, Issue 9 2009Lorenzo Leggio Background:, Heavy drinking may increase blood glucose levels. Moreover, in alcohol-dependent subjects, glucose may play a putative role in alcohol preference. Methods:, This study investigated the relationship between blood glucose levels and both alcohol heavy drinking and craving in alcohol-dependent subjects participating in the COMBINE Study. The primary objective was to evaluate the relationship between baseline (pretreatment) glucose levels and percentage of heavy drinking day (PHDD) during treatment. The secondary objective was to evaluate the relationship between glucose levels, baseline PHDD, and craving measured by the Obsessive Compulsive Drinking Scale (OCDS). Results:, This analysis consisted of 1,324 participants. Baseline glucose levels were significantly and positively associated with PHDD during treatment [F(1, 1225) = 5.21, p = 0.023], after controlling for baseline PHDD [F(1, 1225) = 36.25, p < 0.0001], gender [F (1, 1225) = 3.33, p = 0.07], and body mass index (BMI) [F(1, 1225) = 0.31, p = 0.58]. Higher glucose levels at baseline were associated with a higher percentage of PHDD at pretreatment [F(1, 1304) = 5.96, p = 0.015], after controlling for gender [F(1, 1304) = 0.29, p = 0.59] and BMI [F(1, 1304) = 0.90, p = 0.34]. Glucose was not significantly associated with the OCDS total score [F(1, 1304) = 0.12, p = 0.73], the OCDS Obsessive subscale [F(1, 1304) = 0.35, p = 0.56], or the OCDS Compulsive subscale [F(1, 1304) = 1.19, p = 0.28] scores, after controlling for gender and BMI. Discussion:, A link between pretreatment glucose levels and heavy drinking during treatment was found, suggesting a role of glucose in predicting heavy alcohol consumption. Although caution is needed in the interpretation of these results, elevated glucose and heavy drinking may be affected by a common mechanism and manipulations affecting glucose regulation may influence alcohol consumption. [source] Glucocorticoid replacement is associated with hypertriglyceridaemia, elevated glucose and higher non-HDL cholesterol and may diminish the association of HDL cholesterol with the ,629C>A CETP promoter polymorphism in GH-receiving hypopituitary patientsCLINICAL ENDOCRINOLOGY, Issue 3 2008Robin P. F. Dullaart Summary Objectives, The effect of glucocorticoid substitution on the prevalence of metabolic syndrome components (NCEP ATP III criteria) and serum lipid levels was determined in GH-replaced hypopituitary patients. As glucocorticoid replacement is associated with a pronounced decrease in plasma cholesteryl ester transfer protein (CETP) activity, we also tested associations of HDL cholesterol with the ,629C>A CETP promoter polymorphism in subjects with and without ACTH deficiency. Design and patients, In a university setting, we retrieved protocolized clinical and laboratory data from 165 adult hypopituitary patients, who had received GH for 1 year. Results, After adjustment for age, sex and smoking, non-HDL cholesterol (P = 0·05) and triglycerides (P = 0·004) were higher, but HDL cholesterol was not decreased in 117 glucocorticoid (mainly cortisone acetate in two divided doses) receiving subjects compared to 48 ACTH-sufficient subjects. The prevalence of elevated plasma glucose and/or diabetes (P = 0·04) and hypertriglyceridaemia (P = 0·005), but not of other metabolic syndrome components, was higher in glucocorticoid-replaced subjects. HDL cholesterol was higher in ,629 A allele carriers compared to ,629CC homozygotes in ACTH-sufficient subjects (P = 0·04), but not in glucocorticoid-treated subjects (P = 0·13). Multiple linear regression analysis demonstrated that only in ACTH-sufficient subjects, HDL cholesterol was independently related to this CETP gene variation (P = 0·03). Conclusions, In GH- and glucocorticoid-replaced hypopituitary patients, serum non-HDL cholesterol and triglycerides are higher and the prevalence of hyperglycaemia is increased, but HDL cholesterol is not decreased. Conventional glucocorticoid replacement appears to diminish the association of HDL cholesterol with a common CETP gene variation. [source] | ||||||||||