Time course and dose response of alpha tocopherol on oxidative stress in haemodialysis patients

Ashleigh Reed,Robert G Fassett,Jeff S Coombes,Yeoung Jee Cho

doi:10.1186/1471-2369-10-32

Abstract

BackgroundOxidative stress is associated with increased cardiovascular morbidity and mortality particularly in patients with end stage kidney disease. Although observational data from the general population has shown dietary antioxidant intake is associated with reduced cardiovascular morbidity and mortality, most clinical intervention trials have failed to support this relationship. This may be a consequence of not using an effective antioxidant dose and/or not investigating patients with elevated oxidative stress. The SPACE study, conducted in haemodialysis patients, reported that 800 IU/day of alpha tocopherol significantly reduced cardiovascular disease endpoints. A recent time course and dose response study conducted in hypercholesterolaemic patients that found 1600 IU/day of alpha tocopherol was an optimal dose. There is no such dose response data available for haemodialysis patients. Therefore the aim of this study is to investigate the effect of different doses of oral alpha tocopherol on oxidative stress in haemodialysis patients with elevated oxidative stress and the time taken to achieve this effect.MethodsThe study will consist of a time-course followed by a dose response study. In the time course study 20 haemodialysis patients with elevated oxidative stress will take either 1600 IU/day natural (RRR) alpha tocopherol for 20 weeks or placebo. Blood will be collected every two weeks and analysed for a marker of oxidative stress (plasma F2-isoprostanes) and alpha tocopherol. The optimum time period to significantly decrease plasma F2-isoprostanes will be determined from this study. In the dose response study 60 patients will be randomised to receive either placebo, 100, 200, 400, 800 or 1600 IU/day of natural (RRR) alpha tocopherol for a time period determined from the time course study. Blood will be collected at baseline and every two weeks and analysed for plasma F2-isoprostanes and alpha tocopherol. It is hypothesised that doses ≥ 800 IU of vitamin E will be required to significantly decrease plasma F2-isoprostanes.DiscussionThis study will determine the time and dose required for alpha tocopherol to significantly decrease oxidative stress in haemodialysis patients. Data will be used to plan a large randomised controlled trial to assess the effects of alpha tocopherol on cardiovascular outcomes in haemodialysis patients.Trial RegistrationACTRN12609000608268

Highlights

Oxidative stress is associated with increased cardiovascular morbidity and mortality in patients with end stage kidney disease
Oxidative stress is an important contributor to the development of atherosclerosis and cardiovascular morbidity and mortality [1]
Observational studies suggest diets high in antioxidants such as alpha tocopherol may be associated with decreased cardiovascular disease [2,3]

Summary

Introduction

Oxidative stress is associated with increased cardiovascular morbidity and mortality in patients with end stage kidney disease. Observational data from the general population has shown dietary antioxidant intake is associated with reduced cardiovascular morbidity and mortality, most clinical intervention trials have failed to support this relationship. This may be a consequence of not using an effective antioxidant dose and/or not investigating patients with elevated oxidative stress. Chronic kidney disease is associated with high levels of oxidative stress, and treatment with haemodialysis can further increase oxidative stress levels, which may contribute to high level of cardiovascular disease in these patients [1,12] These patients have a 10-20 times higher rate of cardiovascular disease morbidity and mortality compared to healthy people [13,14]

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