The effects of vitamin E on platelet activity in beta-thalassaemia patients.
A double-blind, crossover, placebo-controlled study of the effect of vitamin E on platelet functions was performed on nine splenectomized and 16 non-splenectomized beta-thalassaemia/haemoglobin E (beta-thalassaemia/HbE) patients. The patients were supplemented with a daily dose of vitamin E (525 IU) for 3 months. The functions of platelets were assessed by adenosine diphosphate (ADP)-induced platelet aggregation and adenosine triphosphate release. Plasma alpha-tocopherol, plasma thiobarbituric reactive substances (TBARs) and serum ferritin levels represented patients' antioxidant status, lipid peroxidation status and iron status respectively. Before experimentation, all patients had low plasma alpha-tocopherol levels. The splenectomized patients showed severe iron overload iron, had higher plasma TBAR levels and their platelets were more reactive to ADP than those of non-splenectomized patients. Three months of daily vitamin E supplementation resulted in a significant increase in plasma alpha-tocopherol levels and reduction in plasma TBAR levels in all patients. Serum ferritin levels of the patients were not altered; however, vitamin E reduced the platelet reactivity of the splenectomized patients towards normal levels. The influence of vitamin E on platelet reactivity may result in delaying hypoxaemia and pulmonary occlusion that commonly occurs in splenectomized beta-thalassaemia/HbE patients.
Unchern
Supeenun
S
Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand. scsuc@mahidol.ac.th
Laoharuangpanya
Narumol
N
Phumala
Noppawan
N
Sipankapracha
Pornpan
P
Pootrakul
Pensri
P
Fucharoen
Suthat
S
Wanachivanawin
Wanchai
W
Chantharaksri
Udom
U
D000328:Adult; D001792:Blood Platelets / Q000187:drug effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005293:Ferritins / Q000097:blood; D006446:Hemoglobin E; D006801:Humans; D015227:Lipid Peroxidation; D008297:Male; D010976:Platelet Count; D013156:Splenectomy; D018709:Statistics, Nonparametric; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014810:Vitamin E / Q000097:blood / Q000627:therapeutic use*; D017086:beta-Thalassemia / Q000097:blood / Q000188:drug therapy* / Q000601:surgery
D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E; D005293:Ferritins; D006446:Hemoglobin E