Influence of vitamin E on platelet function in humans

Area of Science:

• Biochemistry
• Hematology
• Nutritional Science

Background:

• Alpha-tocopherol (vitamin E) is a natural antioxidant.
• In vitro studies suggest vitamin E inhibits platelet aggregation and release.
• This effect was hypothesized to stem from reduced cyclooxygenase activity and lipid peroxide formation.

Purpose of the Study:

• To investigate the in vitro and ex vivo effects of alpha-tocopherol on platelet function.
• To explore the potential role of vitamin E in preventing thromboembolic disease.

Main Methods:

• Platelet aggregation and release assays were performed in vitro.
• Platelet function was assessed in individuals supplemented with alpha-tocopherol (400-1200 IU/day).
• Platelet adhesion was measured in a laminar flow chamber at varying shear rates using alpha-tocopherol-enriched platelets.

Main Results:

• In vitro tests showed alpha-tocopherol inhibited platelet aggregation and release.
• Ex vivo studies revealed no significant reduction in platelet aggregation with dietary supplementation.
• Alpha-tocopherol significantly inhibited platelet adhesion to collagen, fibrinogen, and fibronectin at doses as low as 200 IU/day.
• Adherent platelets showed altered morphology (short, rounded projections) instead of typical pseudopodia.

Conclusions:

• The discrepancy between in vitro and ex vivo findings may be due to attainable vitamin E levels in platelets and plasma.
• Dietary alpha-tocopherol supplementation demonstrates significant inhibitory activity on platelet adhesion.
• Vitamin E may play a role in managing thromboembolic disorders, potentially in combination with antiplatelet agents.