Endogenous and copper-induced lipid peroxidation and antioxidant activity of serum in hypercholesterolemic subjects.

Endogenous malondialdehyde and diene conjugate levels were increased in hypercholesterolemic subjects with serum cholesterol levels above 240 mg/dl as compared to normocholesterolemic subjects (below 20 mg/dl). A decrease in vitamin E/cholesterol and vitamin C/cholesterol ratios was observed in serum of hypercholesterolemic individuals. However, the susceptibility of serum to copper-induced lipid peroxidation and antioxidant activity were found unchanged. The present study indicates that hypercholesterolemic subjects have a high level of circulating lipid peroxides and that a higher tendency towards atherosclerosis in these subjects may be related to increased baseline levels of serum lipid peroxides.