Effects of vitamin E administration on platelet function in diabetes mellitus.
A decrease in the vitamin E content of human diabetic platelets is closely associated with the accelerated platelet aggregation and platelet prostaglandin metabolism seen in patients with diabetes mellitus. We investigated the effect of vitamin E supplementation on these abnormalities of physiological function and prostaglandin metabolism in 14 non-insulin dependent diabetics with proliferative retinopathy. ADP-induced platelet aggregation was inhibited in vitro by the addition of vitamin E in a dose-dependent manner. However, in lower concentrations considered to be physiological doses in vivo, significantly greater inhibition was observed in diabetic platelets than in the control platelets. Next, alpha-tocopheryl nicotinate was administered to diabetics at a daily dose of 600 mg. The platelet vitamin E content was restored to control levels in 13 of the 14 patients after 2-4 weeks of daily administration. The ADP-induced platelet aggregation rate, platelet thromboxane B2 (TXB2, a stable metabolite of TXA2, a vasoconstrictor production, and plasma TXB2 level were low in all 14 diabetics. In contrast, plasma 6-keto-PGF 1 alpha (a stable metabolite of PGI2, a vasodilator) was significantly increased and therefore the 6-keto-PGF 1 alpha/TXB2 ratio in plasma was restored to within normal limits. These results indicate that vitamin E may improve platelet function and prostaglandin metabolism in diabetes mellitus and may be able to provide further beneficial effects in relation to the development of diabetic vascular complications.
Kunisaki
M
M
Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Umeda
F
F
Inoguchi
T
T
Watanabe
J
J
Nawata
H
H
D015121:6-Ketoprostaglandin F1 alpha / Q000097:blood; D000244:Adenosine Diphosphate / Q000494:pharmacology; D001786:Blood Glucose / Q000378:metabolism; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy; D003925:Diabetic Angiopathies / Q000097:blood; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D012016:Reference Values; D013929:Thromboxane B2 / Q000097:blood; D013997:Time Factors; D014810:Vitamin E / Q000097:blood / Q000627:therapeutic use*
D015121:6-Ketoprostaglandin F1 alpha; D000244:Adenosine Diphosphate; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D010975:Platelet Aggregation Inhibitors; D013929:Thromboxane B2; D014810:Vitamin E