Amyloid b Levels in Human Red Blood Cells

Amyloid b-peptide (Ab) is hypothesized to play a key role by oxidatively impairing the capacity of red blood cells (RBCs) to deliver oxygen to the brain. These processes are implicated in the pathogenesis of Alzheimer’s disease (AD). Although plasma Ab has been investigated thoroughly, the presence and distribution of Ab in human RBCs are still unclear. In this study, we quantitated Ab40 and Ab42 in human RBCs with ELISA assays, and provided evidence that significant amounts of Ab could be detected in RBCs and that the RBC Ab levels increased with aging. The RBC Ab levels increased with aging. On the other hand, providing an antioxidant supplement (astaxanthin, a polar carotenoid) to humans was found to decrease RBC Ab as well as oxidative stress marker levels. These results suggest that plasma Ab40 and Ab42 bind to RBCs (possibly with aging), implying a pathogenic role of RBC Ab. Moreover, the data indicate that RBC Ab40 and Ab42 may constitute biomarkers of AD. As a preventive strategy, therapeutic application of astaxanthin as an Ab-lowering agent in RBCs could be considered as a possible anti-dementia agent