Astaxanthin has no effect on arterial stiffness, oxidative stress, or inflammation in renal transplant recipients: a randomized controlled trial (the XANTHIN trial).
Coombes JS, Sharman JE, et al.Am J Clin Nutr 2016; Jan;103(1):283-9.
Aims
To investigate the effects of oral astaxanthin on arterial stiffness, oxidative stress, and inflammation in renal transplant recipients.
Interventions
Participants were randomized to receive either 12mg astaxanthin orally, or placebo every day for a year.
Participants
61 renal transplant recipients aged 18-85 years
Outcomes
Primary outcomes measured were arterial stiffness, oxidative stress and inflammation. Secondary outcomes were vascular function, carotid artery intima-media thickness, augmentation index, central blood pressure, subendocardial viability ratio, and additional measures of oxidative stress and inflammation.
Follow-up
12 months
CET Conclusions
This well designed, double-blind placebo controlled trial investigated the role of the antioxidant Astaxanthin on arterial stiffness and biomarkers of inflammation and oxidative stress in renal transplant recipients. Animal studies and small human series had suggested a potential benefit, which could be of clinical importance given the high rates of cardiovascular disease in transplant recipients. In fact, no difference in any of the measured parameters was found in this study. There are some caveats. Firstly, the study uses surrogate biomarkers for cardiovascular outcome. Whilst aortic pulse-wave velocity has been shown to relate to cardiovascular mortality in transplant recipients, the biomarkers of inflammation and oxidative stress used are less well validated. Secondly, the study is underpowered due to issues recruiting and an underestimation of outcome variability in the power calculation. This raises the possibility that a true effect may have been missed.
Data analysis
Modified intention-to-treat analysis
Trial registration
New Zealand Clinical Trials Registry - ACTRN12608000159358