Effect of vitamin E on hydrogen peroxide production by human vascular endothelial cells after hypoxia/reoxygenation.
Changes in oxidative stress status play an important role in tissue injury associated with ischemia -- reperfusion events such as those that occur during stroke and myocardial infarction. Endothelial cells (EC) from 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-dependent manner. EC supplemented with 23 or 28 mM vitamin E in the media for 22 h were maintained at normoxia (20% O2, 5% CO2, and balance N2) or exposed to hypoxic conditions (3% O2, 5% CO2, and balance N2) for 12 h, followed by reoxygenation (20% O2) for 30 min. Saphenous EC supplemented with 23 mM vitamin E produced less (p < 0.05) H2O2 than unsupplemented controls, both at normoxic condition (supplemented: 4.9 +/- 0.05 vs. control: 10.9 +/- 1.3 pmol/min/10(6) cells) and following hypoxia/reoxygenation (supplemented: 6.4 +/- 0.78 vs. control: 17.0 +/- 2.7 nmol/min/10(6) cells). In contrast, aortic EC, which were found to have higher superoxide dismutase and catalase activity than EC from saphenous vein, did not produce any detectable levels of H2O2. Following hypoxia/reoxygenation, the concentration of vitamin E in supplemented 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 aortic 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). Therefore, enrichment of vitamin E in EC decreases H2O2 production and thus may reduce the injury associated with ischemia-reperfusion events.
Antioxidant Research Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA.
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Martin
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Zulueta
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Hassoun
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Blumberg
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Meydani
D000975:Antioxidants / Q000378:metabolism; D001011:Aorta; D002374:Catalase / Q000032:analysis / Q000378:metabolism; D015687:Cell Hypoxia; D002470:Cell Survival; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D016166:Free Radical Scavengers / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D010100:Oxygen / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012501:Saphenous Vein; D013482:Superoxide Dismutase / Q000032:analysis / Q000378:metabolism; D014810:Vitamin E / Q000378:metabolism / Q000494:pharmacology*
D000975:Antioxidants; D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D014810:Vitamin E; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D010100:Oxygen