Lutein and inflammation

It has been shown that, besides absorbing blue light and quenching free oxygen radicals, lutein also has anti-inflammatory properties. This may have implications in Age related Macular Degeneration (AMD), because an inflammatory mechanism involving the alternative complement pathway has been implicated in the pathogenesis of this disease. In addition, various complement activation products were increased in the circulation of AMD patients, providing evidence for a systemic inflammatory component to the disease pathogenesis. It may well be lutein administration affects the inflammatory component of AMD. First clues came from studies showing that administering lutein had a beneficial effect in an experimental model of AMD. Recently, we have reported that daily supplementation with lutein over a time period of 12 months led to a significant decrease in the plasma levels of the complement factors Factor D (FD), C3d, C5a, and sC5b-9. However, the mechanism of this finding is not clear. The activation of the alternative complement pathway involves a number of cleavage reactions and amplification steps whereby complement components interact with each other in a strictly regulated manner. FD is a rate limiting enzyme in the activation sequence of the alternative pathway and as such a key player in this complement homeostasis. FD is also known as adipsin, since its main source is adipose tissues, where it is secreted by mature adipocytes. Since adipose tissue is also a main storage site for carotenoids such as lutein and zeaxanthin, we setup a study to investigate whether lutein influences FD secretion by adipose cells as a possible mechanism for the results above. Data, showing that lutein suppresses FD expression by mature adipose cells, both at the protein and the mRNA level, will be discussed