Meeting Abstract
Understanding the interactions between aging, oxidative stress, and altered red blood cell (RBC) physiology remains a challenge due to the complexity of the antioxidant defense system and numerous potential target sites of oxidizing agents. Here, we investigated the relationship between RBC damage and aging by developing a new approach to measuring oxidative stress. Using a series of in vitro and in vivo procedures, we systematically explored (1) whether avian RBCs generate fluorescent heme degradation products (HDPs), (2) whether HDPs interact with RBC membranes, (3) whether HDPs are linked to impaired RBC integrity, and (4) whether aging is associated with elevated HDPs. Using zebra finches (Taeniopygia guttata), we found that avian RBCs exposed in vitro to hydrogen peroxide had a dose-response increase in fluorescent HDPs and that HDPs associated with RBC membranes. Moreover, in vitro exposure to hydrogen peroxide caused a 25% reduction in relative hemoglobin and converted 95% of hemoglobin to non-oxygen binding methemoglobin, further indicating hemoglobin degradation. In addition, elevated HDP fluorescence was associated with decreased membrane integrity and increased erythrocyte osmotic fragility in vivo. To examine the relationship between HDPs and aging, we collected RBCs from zebra fiches of known ages (600-2300 days old) and found a positive correlation between HDPs and age. This study is the first to demonstrate HDP fluorescence in a non-mammalian system, and suggests HDPs may be a useful tool for measuring oxidative stress and understanding the aging process.
