EFFECT OF VITAMIN-E ON HYDROGEN-PEROXIDE PRODUCTION BY HUMAN VASCULARENDOTHELIAL-CELLS AFTER HYPOXIA REOXYGENATION/

Changes in oxidative stress status play an important role in tissue in jury associated with ischemia-reperfusion events such as those that oc cur during stroke and myocardial infarction. Endothelial cells (EC) fr om human saphenous vein and aorta were incubated for 22 h and found to take up vitamin E from media containing 0-60 mM vitamin E in a dose-d ependent manner. EC supplemented with 23 or 28 mM vitamin E in the med ia for 22 h were maintained at normoxia (20% O-2, 5% CO2, and balance N-2) or exposed to hypoxic conditions (3% O-2, 5% CO2, and balance N-2 ) for 12 h, followed by reoxygenation (20% O-2) for 30 min. Saphenous EC supplemented with 23 mh4 vitamin E produced less (p < 0.05) H2O2 th an unsupplemented controls, both at normoxic condition (supplemented: 4.9 +/- 0.05 vs. control: 10.9 +/- 1.3 pmol/min/10(6) cells) and follo wing hypoxia/reoxygenation (supplemented: 6.4 +/- 0.78 vs. control: 17 .0 +/- 2.7 nmol/min/10(6) cells). In contrast, aortic EC, which were f ound to have higher superoxide dismutase and catalase activity than EC from saphenous vein, did not produce any detectable levels of H2O2. F ollowing hypoxia/reoxygenation, the concentration of vitamin E in supp lemented saphenous EC was 62% lower than cells maintained at normoxia (0.19 +/- 0.03 vs. 0.5 +/- 0.12 nmoles/10(6) cells, p < 0.001); in aor tic EC vitamin E content was reduced by 18% following reoxygenation (0 .86 +/- 0.16 vs. 0.70 +/- 0.09 nmoles/10(6) cells, p < 0.05). Therefor e, enrichment of vitamin E in EC decreases H2O2 production and thus ma y reduce the injury associated with ischemia-reperfusion events.