Plasma F2 isoprostanes -: Direct evidence of increased free radical damage during acute hyperglycemia in type 2 diabetes

OBJECTIVE - Acute hyperglycemia in type 2 diabetes increases the generation of plasma 8-epi-prostaglandin F-2 (8-epi-PGF(2alpha)) isoprostane, a sensitive direct marker of in vivo free radical oxidative damage to membrane phospholipids. RESEARCH DESIGN AND METHODS - A total of 21 patients with type 2 diabetes underwent an oral 75-g glucose tolerance test. Plasma 8-epi-PGF(2alpha) isoprostane concentrations (by gas chromatography [GC]/mass spectrometry [MS]), intralymphocyte reduced-to-oxidized glutathione ratios, and plasma total antioxidant capacity were measured at baseline and 90 min after glucose loading. RESULTS - Plasma 8-epi-PGF(2alpha) isoprostane concentrations rose significantly (P = 0.010) from 0.241 +/- 0.1 to 0.326 +/- 0.17 ng/l after 90 min. Intracellular oxidative balance and plasma antioxidant capacity did not change in either group. CONCLUSIONS- Plasma concentrations of 8-epi-PGF(2alpha) isoprostane increase during acute hyperglycemia in type 2 diabetes, providing direct evidence of free radical-mediated oxidative damage and demonstrating a pathway for an association between acute rather than fasting hyperglycemia and macrovascular risk in type 2 diabetes.