The lifespan of red blood cells (relationship to their hemorheologic properties)

Abstract

Red blood cells (RBCs) live for approximately 120 days. As they reach this age, they become fragile and are removed from the circulation. However, despite rather intense investigation, the physiologic mechanism that determine the RBC lifespan are not yet well understood. Significant changes occur in the biomechanic or rheologic properties of the senescent red blood cell membrane. In addition, changes in metabolic requirements or environmental oxygen availability cause modulation of the RBC number, blood rheology, oxygen affinity of hemoglobin and also their lifetime. Its eventual removal from the circulation is generally believed to be a consequence of declining deformability, Maturation and aging of RBCs is accompanied by multiple processes occurring at various rates driving the circulating RBCs from adolescence to senescence within this period. A lot of investigations of the mechanisms in control of regulation of erythropoiesis, RBC maturation and aging, as well as the processes involved in recognition of senescent RBCs and their clearance have shown that these are related with their rheologic properties and lifespan. During maturation and aging, the resulting “markers of senescence” are recognized and cleared by the macrophages from blood circulation. One or multiple marker of senescence appear early if there are abnormal conditions or disorders, e.g.,excessive oxidative stress, membrane changes or metabolic abnormalities.Although they have effective mechanism to quench ROS, RBCs carry oxygen efficiently throughout their lives until they are damaged by ROS. Of course, today, we can not fully explain the mechanisms of the clearance of RBCs during their lifespan. But I hope this mini review summarizes an overview of the variety of opinions reflecting these cases, and also provides the base for future discussions. © 2022, Bulgarska Akademiya na Naukite. All rights reserved.