Aging and destruction of blood erythrocytes in mice

Erythrocytes evolved to carry out the crucial function of transportation of oxygen from lungs to various tissues in the body and to carry back carbon dioxide. Absence of a nucleus in erythrocytes facilitates their easy movement in blood capillaries and make space for large quantities of haemoglobin, the oxygen carrier molecule, but renders the cells ill equipped to effectively repair themselves from oxidative and other damages. Turnover rate of erythrocytes is fast and the average life span of murine erythrocytes in blood is only 50 days. What age related changes occur in circulating erythrocytes and which of these changes are crucial determining factors in triggering the destruction of old erythrocytes, are not well understood. The main reason for a lack of information in this area is the fact that there were not available any good and easy to perform technique to identify circulating erythrocytes of different age groups. We have recently developed a technique that involved in vivo biotinylation of erythrocytes in two steps that has allowed us for the first time to objectively assess age-related changes in blood erythrocytes. We have utilized this technique to study various aspects of aging of murine erythrocytes. On the basis of these results, our current thinking about the process of erythrocyte aging in vivo is summarized in the this article.