Red Cell Survival: Relevance and Mechanism Involved

Red blood cells (RBCs) often have a short circulating half-life in hemodialysis patients, which increases the difficulty of achieving a stable hemoglobin level. Fluctuations in erythropoietin (EPO) levels contribute to this increased RBC turnover because a decline in the level of EPO triggers the preferential destruction of newly-formed RBC, a process termed neocytolysis. The RBCs that are released during the treatment of renal anemia are often hypochromic, with a low content of iron; these RBCs are vulnerable to rapid turnover because iron-deficiency affects RBCs in several ways, such as, increased exposure of the phagocytic signaling molecule phosphatidylserine, loss of deformability, and increased oxidative stress. Both EPO fluctuation and the release of iron-deficient RBCs are characteristic events occurring during the management of renal anemia, and the shorter RBC lifetime is a component of the large fluctuations in hemoglobin level seen in patients on hemodialysis.