Oxidative stress could precede endothelial dysfunction and insulin resistance in Indian Mauritians with impaired glucose metabolism

Aims/hypothesis. To measure oxidative stress, endothelial dysfunction and i nsulin resistance in Indian Mauritians at different stages of development o f Type II (non-insulin-dependent) diabetes mellitus. Methods. Plasma total 8-epi-PGF(2 alpha), an indicator of oxidative stress, was determined in age-matched subjects with normal glucose metabolism (n = 39), impaired glucose tolerance (n = 14), newly diagnosed diabetes (n = a) and established diabetes (n = 14). Plasma glucose and insulin were measure d at baseline and 2 h following an oral glucose tolerance test. Endothelial function was assessed by non-invasive digital pulse wave photoplethysmogra phy. Results. Plasma 8-epi-PGF(2 alpha) increased in subjects with impaired gluc ose tolerance (p < 0.05) compared with control subjects, and was even highe r in newly diagnosed diabetic patients (p < 0.01) and established (p < 0.01 ) diabetic patients. A tendency towards reduced endothelial function in sub jects with impaired glucose tolerance became significant in patients with n ewly diagnosed and established diabetes (p < 0.01), and was correlated with 8-epi-PGF(2 alpha) (r=0.36, p < 0.01). Insulin resistance (homeostasis mod el assessment) did not change in subjects with impaired glucose tolerance c ompared with control subjects, but increased in newly diagnosed (p < 0.01) and established (p < 0.001) diabetic subjects. The 8-epi-PGF(2<alpha>) was correlated with fasting glucose (r = 0.50, p < 0.001), triglycerides (r = 0 .40, p < 0.001) and insulin resistance (r = 0.35, p < 0.001). Conclusion/interpretation. Oxidant stress is an early event in the evolutio n of Type II diabetes and could precede the development of endothelial dysf unction and insulin resistance.