Abstract
Purpose:
Dietary factors have been implicated in the pathogenesis of AMD and intervention trials have shown that certain supplements containing lutein can halt the progression of AMD. Lutein is selectively taken up by the primate retina and plays an important role as a filter for harmful blue light and as an antioxidant. On the other hand lutein also shows systemic anti-inflammatory properties (Kijlstra et al. Prog Retin Eye Res.31:303-15, 2012). Inflammation and especially complement activation seem to play an important role in AMD. Whether lutein might affect complement activation is not clear and was therefore the subject of our study. As a model we chose to study the effect of lutein on the activation of the complement system, whereby the level of circulating sC5b-9 was chosen as a marker.
Methods:
Seventy individuals with signs of early AMD were included in this study. All subjects were randomly assigned to receive a daily dose of 10mg lutein or placebo for one year. EDTA blood samples were collected at the start of the study and at four-month time intervals. The plasma concentration of the soluble membrane attack complex sC5b-9 was determined by ELISA.
Results:
SC5b-9 showed a significant 1.1 ng/ml monthly decrease in the lutein group (p<0.001), resulting in a decrease from 60.3 ng/ml at baseline to 46.3 ng/ml at 12 months. An earlier analysis of blood samples from this study showed that lutein supplementation also led to a significant decrease in the plasma C5a levels. Analysis of the change of C5a and sC5b-9 over the one-year intervention period showed a significant correlation. For the placebo group we found a slight but statistically significant 0.6 ng/ml monthly increase in plasma sC5b-9 concentration (p=0.001), resulting in an increase from 51.6 ng/ml at baseline to 58.4 ng/ml at 12 months.
Conclusions:
Lutein supplementation markedly decreased circulating levels of the complement membrane attack complex sC5b-9, providing further evidence for the anti-inflammatory properties of this xanthophyll.
Keywords: 557 inflammation •
444 carotenoids/carotenoid binding proteins •
412 age-related macular degeneration