ADMINISTRATION OF ANTIOXIDANT VITAMINS DOES NOT ALTER PLASMA FIBRINOLYTIC-ACTIVITY IN SUBJECTS WITH CENTRAL OBESITY

In vitro studies suggest that oxidized low density lipoprotein inhibit s fibrinolysis by stimulating the production of plasminogen activator inhibitor -1 (PAI). We assessed the effects of dietary antioxidant vit amins for four weeks on three indices of copper mediated oxidation of very low and low density lipoproteins (VLDL + LDL) and plasma fibrinol ytic activities in 15 male subjects with central obesity, a condition associated with increased PAI activity. Vitamin administration resulte d in a decrease in production bf thiobarbituric acid reactive substanc es from 29.3 +/- 3.9 to 13.6 +/- 3.5 nmoles/mg VLDL + LDL protein (mea n +/- SE, p < 0.003), an increase in the lag phase of conjugated diene formation from 94.8 +/- 5.5 to 225.0 +/- 31.9 min (p < 0.001) and an increase in reactivity of lysine residues from 73.6% +/- 4.8% to 86.8% +/- 3.6% (p < 0.034) demonstrating a reduction in the susceptibility of the lipoproteins to oxidation. However, antioxidant vitamins had no effect on plasma PAI activity, PAI antigen, tissue-type plasminogen a ctivator activity and antigen, fibrinogen and fibrin degradation produ cts. These results do not support the hypothesis that lipoprotein oxid ation is a significant cause of impaired fibrinolysis in men with cent ral obesity.