Lipid peroxidation and catalase in diabetes mellitus with and without ischemic stroke.

Production of reactive oxygen species (ROS) increased in diabetic patients and oxidative damage may contribute to the development of diabetic complications. Malondialdehyde is known as marker of the oxidative damage. Catalase is one of antioxidative factors involved in elimination of ROS In this study, the plasma level of lipid peroxides and plasma catalase activity in 315 patients with diabetes mellitus were assayed. We also included 114 non-diabetic healthy controls whose age, sex were matched to the diabetic patients. The plasma levels of lipid peroxides (LPO) were determined by spectrophotometric method modified by Satoh and Yagi. Lipid peroxidation was estimated by the plasma level of malondialdehyde (MDA). In controls mean value of plasma lipid peroxides was 1.329 +/- 0.118 nmol/ml. In diabetic patients with ischemic stroke MDA level was 2.919 +/- 0.182 nmol/l; p<0.001, and in patients without ischemic stroke the MDA level was 2.329 +/- 0.149 nmol/l; p<0.05; between diabetic patients with ischemic stroke and patients without ischemic stroke p<0.01. The high level of lipid peroxides might induce a self-maintained chronic process which, in time, might lead to the aggravation of the macro- and microangiopathy in diabetes. The plasma levels of catalase were determined by Goth's spectrophotometric method. In 114 healthy persons the mean value of plasma catalase (CAT) activity was 115.3 +/- 14.5 MU/l with less plasma catalase for females (108.7 +/- 12.4 MU/l) than for males (118.9 +/- 16.6 MU/l). Mean value of plasma CAT was (102.4 +/- 12.7 MU/l in patients with ischemic stroke, p<0.001 and 116.3 +/- 18.7 MU/l in patients without ischemic stroke, p<0.05); between diabetic patients with ischemic stroke and patients without ischemic stroke p<0.01. Our results revealed a decrease in plasma CAT activity in patients with diabetes mellitus and ischemic stroke as compared to patients with diabetes mellitus without ischemic stroke. We can conclude that in diabetic patients the decrease in plasma CAT activity is the consequence of oxidative modifications. These results suggest that diabetic patients have significantly increased oxidative damage.