| In our studies we aimed to evaluate cross-sectional differences in plasma lipid profile and markers of oxidation (Study 1)—plasma antibodies to oxidatively modified proteins (aOx), soluble vascular adhesion molecule (sVCAM-1), and plasma myeloperoxidase protein (MPO)—across a spectrum of physical activity, in addition to longitudinal changes (Study 2) with 8 weeks of exercise, in previously sedentary individuals with and without the introduction of an antioxidant (vitamin E). In Study 1, fit females displayed significantly lower total and LDL cholesterol than sedentary controls (152.79 mg/dl vs. 184.68 mg/dl and 88.87 mg/dl vs. 106.96 mg/dl, respectively; p < 0.01); however their HDL levels remained constant irrespective of fitness. Males displayed similar reductions in total and LDL cholesterol with fitness, but showed significantly increased HDL levels in fit compared to sedentary participants (49.20 mg/dl vs. 41.24 mg/dl, respectively; p < 0.01). aOx followed an adaptive trend in both men and women, increasing from sedentary to moderate and declining from moderate to fit (.174 vs. .267 vs. .223, respectively). Male and female fit participants displayed significantly higher sVCAM-1 than their sedentary counterparts (792.53 ng/ml vs. 340.79 ng/ml, respectively; p < 0.001), while MPO declined systemically with fitness and was significantly reduced in the fit group compared to sedentary controls (1.57 ng/ml vs. 4.79 ng/ml, respectively; p < 0.001). In Study 2, vitamin E and 8 weeks of exercise appeared to have a pro-oxidant effect. Total, LDL, and HDL cholesterol increased significantly from baseline to 8 weeks in the male and female supplemented group (173.21 mg/dl vs. 184.08 mg/dl; p < 0.001, 100.70 mg/dl vs. 109.89 mg/dl; p < 0.001, 52.60 mg/dl vs. 56.49 mg/dl; p < 0.01, respectively), however no change was observed in participants taking placebo, even when stratified by gender. Also, aOx and sVCAM-1 increased significantly with supplementation and exercise from baseline to 8 weeks in both men and women (.193 vs. .240 and 328.01 vs. 380.39, respectively; p < 0.10), while the placebo group showed no change in either of these parameters. Overall these results suggest: (1) estrogen may be a key factor in maintaining HDL at high concentrations, (2) increases in sVCAM-1 with fitness could be indicative of exercise-induced hemodynamic changes, (3) neutrophil degranulation/MPO release could be exhausted with progressive physical activity, (4) 8 weeks of exercise may not be long enough to significantly alter plasma lipid concentrations independently, and (5) the combined pro-oxidant effects of exercise and vitamin E alone (without vitamin C) could keep plasma HDL levels elevated. |
