Effects of simvastatin on plasma antioxidant status and vitamins in hypercholesterolemic patients

Statins are known to possess antioxidant properties in addition to their cholesterol-lowering effects. However, recent studies have suggested that statins reduce the levels of antioxidant vitamins such as vitamin E and coenzyme Q(10), possibly resulting in impaired left ventricular function. We investigated the effects of simvastatin on the blood lipids, LDL oxidation and plasma antioxidant status, and whether these effects were associated with changes in plasma antioxidant vitamin levels.

Simvastatin (20-40 mg/day) was administered for 8 weeks in seventy-six hypercholesterolemic patients. We measured plasma lipids, oxidized LDL, total radical trapping antioxidant potential (TRAP) and plasma antioxidant vitamin levels at baseline and after 8 weeks of simvastatin administration.

Simvastatin significantly lowered serum levels of total cholesterol and LDL-cholesterol by 30.1% and 41.9%, respectively. A significant reduction in oxidized LDL levels (p<0.0001) and improvement in plasma antioxidant status as measured by TRAP (p<0.05) after the 8-week simvastatin treatment were observed. Regarding the effects of simvastatin on plasma antioxidant vitamin levels, there were significant increases in the levels of lipid-corrected retinol (p<0.001), alpha-tocopherol (p<0.001) and gamma-tocopherol (p<0.005) after the 8-week simvastatin treatment. Lipid-corrected levels of coenzyme Q10 and carotenoids remained unchanged after simvastatin treatment.

Our results show that simvastatin reduced blood lipids and circulating oxidized LDL, and improved plasma antioxidant status without altering the antioxidant vitamin system. These data indicate that simvastatin not only decreases blood lipids and circulating oxidized LDL but also increases lipid corrected levels of antioxidant vitamins and may improve plasma antioxidant status synergizing with the biological effects of antioxidants.