The effect of deoxygenation on red cell density: significance for the pathophysiology of sickle cell anemia

Abstract

We have used continuous density gradients made with Percoll-Stractan mixtures to study the effect of deoxygenation on AA and SS cell density. Red cell density is directly correlated with the intracellular hemoglobin concentration and inversely correlated with red cell volume. We find that AA cells become less dense (swell) when deoxygenated under all conditions and that SS cells either become more dense or maintain constant density (shrink or maintain constant volume) when deoxygenated. The response of SS cells is affected by the pH. the amount of potassium present. and the characteristics of the cells (that is. reversibly or irreversibly sickled cells). Irreversibly sickled cells become denser when deoxygenated under all conditions. Below pH 7.25 and at physiologic potassium concentrations (5 meq/liter). reversibly sickled cells become denser when deoxygenated. Furthermore. they remain denser than the CO control cells even after CO is added and the