Study protocol

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

Ashleigh Reed¹ , Yeoung Jee Cho² , Jeff S Coombes¹ and Robert G Fassett^1,2,3

¹School of Human Movement Studies, The University of Queensland, St. Lucia, Queensland, 4072, Australia

²Renal Medicine, Royal Brisbane and Women's Hospital, Brisbane, Queensland, 4029, Australia

³The School of Medicine, The University of Queensland, Brisbane, Queensland, 4029, Australia

author email corresponding author email

BMC Nephrology 2009, 10:32doi:10.1186/1471-2369-10-32

Published:	22 October 2009

Abstract

Background

Oxidative 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.

Methods

The 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.

Discussion

This 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 Registration

ACTRN12609000608268