Plasma antioxidant potency and serum copper levels in atherosclerosis

Blood plasma of patients with arteriosclerosis obliterans and diabetes showed a higher antioxidant potency as compared with plasma of healthy volunteers. Serum copper level in those patients was also elevated, but on the contrary to healthy subjects no correlation between serum copper level and plasma antioxidant potency was found. Similar changes were observed in rabbits fed four weeks with atherogenic diet. Administration of vitamin E increased plasma antioxidant potency, however, only in the patients suffering from arteriosclerosis obliterans with high regime of dosage of vitamin E (3 X 200 mg daily p.o.). N-ethylmaldimide-stimulated (malondialdehyde (MDA)) generation by washed platelets was suppressed by addition of homologous plasma to washed platelet preparation. Preincubation of rat aortic tissue with plasma from healthy volunteers resulted in an increase in PGI2-biosynthesis b 75%. We were not able to demonstrate the antioxidant activity of aortic endothelial cell homogenates. We conclude that antioxidant properties of plasma may play an important role in protection of serum lipids against autooxidation. Antioxidant ability of plasma is not exclusively correlated with plasma copper or ceruloplasmin level.