BACKGROUND: Epidemiologic studies have shown an inverse correlation between acute coronary events and high intake of dietary vitamin E. Recent clinical studies, however, failed to show any beneficial effects of alpha-tocopherol on cardiovascular events. Absence of tocopherols other than alpha-tocopherol in the clinical studies may account for the conflicting results. OBJECTIVE: This study compared the effect of a mixed tocopherol preparation rich in gamma-tocopherol with that of alpha-tocopherol on platelet aggregation in humans and addressed the potential mechanisms of the effect. DESIGN:Forty-six subjects were randomly divided into 3 groups: alpha-tocopherol, mixed tocopherols, and control. ADP and phorbol 12-myristate 13-acetate-induced platelet aggregation, nitric oxide (NO) release, activation of endothelial constitutive nitric-oxide synthase (ecNOS; EC 1.14.13.39) and of protein kinase C (PKC), and ecNOS, superoxide dismutase (SOD; EC 1.15.1.1), and PKC protein content in platelets were measured before and after 8 wk of administration of tocopherols. RESULTS:ADP-induced platelet aggregation decreased significantly in the mixed tocopherol group but not in the alpha-tocopherol and control groups. NO release, ecNOSactivation, and SOD protein content in platelets increased in the tocopherol-treated groups. PKC activation in platelets was markedly decreased in the tocopherol-treated groups. Mixed tocopherols were more potent than alpha-tocopherol alone in modulating NO release and ecNOS activation but not SOD protein content or PKC activation. CONCLUSIONS:Mixed tocopherols were more potent in preventing platelet aggregation than was alpha-tocopherol alone. Effects of mixed tocopherols were associated with increased NO release, ecNOSactivation, and SOD protein content in platelets, which may contribute to the effect on platelet aggregation.
RCT Entities:
BACKGROUND: Epidemiologic studies have shown an inverse correlation between acute coronary events and high intake of dietary vitamin E. Recent clinical studies, however, failed to show any beneficial effects of alpha-tocopherol on cardiovascular events. Absence of tocopherols other than alpha-tocopherol in the clinical studies may account for the conflicting results. OBJECTIVE: This study compared the effect of a mixed tocopherol preparation rich in gamma-tocopherol with that of alpha-tocopherol on platelet aggregation in humans and addressed the potential mechanisms of the effect. DESIGN: Forty-six subjects were randomly divided into 3 groups: alpha-tocopherol, mixed tocopherols, and control. ADP and phorbol 12-myristate 13-acetate-induced platelet aggregation, nitric oxide (NO) release, activation of endothelial constitutive nitric-oxide synthase (ecNOS; EC 1.14.13.39) and of protein kinase C (PKC), and ecNOS, superoxide dismutase (SOD; EC 1.15.1.1), and PKC protein content in platelets were measured before and after 8 wk of administration of tocopherols. RESULTS:ADP-induced platelet aggregation decreased significantly in the mixed tocopherol group but not in the alpha-tocopherol and control groups. NO release, ecNOS activation, and SOD protein content in platelets increased in the tocopherol-treated groups. PKC activation in platelets was markedly decreased in the tocopherol-treated groups. Mixed tocopherols were more potent than alpha-tocopherol alone in modulating NO release and ecNOS activation but not SOD protein content or PKC activation. CONCLUSIONS: Mixed tocopherols were more potent in preventing platelet aggregation than was alpha-tocopherol alone. Effects of mixed tocopherols were associated with increased NO release, ecNOS activation, and SOD protein content in platelets, which may contribute to the effect on platelet aggregation.
Authors: Emilia M Swietlik; Pavandeep Ghataorhe; Kasia I Zalewska; John Wharton; Luke S Howard; Dolores Taboada; John E Cannon; Nicholas W Morrell; Martin R Wilkins; Mark Toshner; Joanna Pepke-Zaba; Christopher J Rhodes Journal: Eur Respir J Date: 2021-04-01 Impact factor: 16.671
Authors: Martha Clare Morris; Julie A Schneider; Hong Li; Christy C Tangney; Sukriti Nag; David A Bennett; William G Honer; Lisa L Barnes Journal: Alzheimers Dement Date: 2014-02-28 Impact factor: 21.566
Authors: Marianne Geiser; John C Lay; William D Bennett; Haibo Zhou; Xiaoyan Wang; David B Peden; Neil E Alexis Journal: J Innate Immun Date: 2013-05-08 Impact factor: 7.349