Transmembrane ion and water transports in erythrocyte volume homeostasis: an overview of the physiologic processes

Abstract

Background: The intraerythrocytic concentrations of ions (Na , K , Cl and HCO ) play key roles in maintaining erythrocyte volume homeostasis. Anisosmotic and isosomotic changes of these ion concentrations challenge erythrocyte volume to either shrink or swell, thereby sending signals to activate regulatory volume mechanisms that are mediated by ion transporters. Ion fluxes directed inwardly or outwardly with obliged water movements do restore the erythrocyte volume to its steady state. These physiological phenomena prevent the erythrocyte from becoming overhydrated or dehydrated with the consequence of intravascular haemolysis or senescent changes associated with eryptosis. Objectives: To review the literature on the physiological processes associated with transmembrane ion and water transports during erythrocyte volume homeostasis. Method: Offline and online libraries were searched with indexing tools using keywords derived from the subject area of review. Conclusions: The review has highlighted the physiological concepts involved in erythrocyte volume homeostasis in relation to the engaged transmembrane ion and water transport systems, which can influence experimental designs to study ion and water channel blockers and channelopathies of erythrocytes.