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Alpha-Tocopherol and endothelial nitric oxide synthesis.
Regine Heller1, Gabriele Werner-Felmayer, Ernst R Werner
1Institute of Molecular Cell Biology, Friedrich-Schiller-University of Jena, Nordhäuser Str. 78, 99089 Erfurt, Germany. heller@zmkh.ef.uni-jena.de
Annals of the New York Academy of Sciences
|March 9, 2005
Summary
Alpha-tocopherol enhances nitric oxide (NO) synthesis by increasing endothelial NO synthase (eNOS) phosphorylation in human cells. This suggests vitamin E
Area of Science:
- Biochemistry
- Cell Biology
- Vascular Biology
Background:
- Nitric oxide (NO) is crucial for vascular tone and homeostasis, produced by endothelial NO synthase (eNOS).
- Reduced NO bioavailability causes endothelial dysfunction, potentially improved by alpha-tocopherol.
- Mechanisms underlying alpha-tocopherol's effects on NO production are not fully understood.
Purpose of the Study:
- To investigate if alpha-tocopherol influences endothelial NO synthesis.
- To elucidate the molecular mechanisms by which alpha-tocopherol affects NO production.
Main Methods:
- Human umbilical vein endothelial cells were treated with alpha-tocopherol.
- NO formation was assessed by measuring citrulline and cGMP levels.
- eNOS phosphorylation at serine 1177 was analyzed.
Main Results:
- Alpha-tocopherol dose-dependently increased ionomycin-induced citrulline and cGMP formation.
- Alpha-tocopherol enhanced eNOS phosphorylation at serine 1177, correlating with increased NO production.
- The effect was dependent on the hydrophobic structure of tocopherol and amplified by ascorbic acid.
Conclusions:
- Alpha-tocopherol may exert vasoprotective effects by boosting endothelial NO formation.
- Ascorbic acid synergizes with alpha-tocopherol to optimize NO production.
- These findings highlight a potential synergistic role of vitamins E and C in vascular health.