Plasma F2 Isoprostanes

OBJECTIVES—Acute hyperglycemia in type 2 diabetes increases the generation of plasma 8-epi-prostaglandin F2 (8-epi-PGF2α) 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-PGF2α 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-PGF2α 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-PGF2α 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.