Modification of the oxygen affinity and intracellular hemoglobin concentration of normal and sickle cells by means of an osmotic pulse.

Important properties of red blood cells (RBCs), including oxygen affinity and intracellular hemoglobin concentration, may be modified by means of an osmotic pulse. The pulse is developed by rapid dilution of a suspension of RBCs to which dimethylsulfoxide has been added. The nature and degree of RBC modification is dependent on the composition of the diluent solution. The purpose of this investigation was to explore the dependence of these changes on diluent composition and to determine the stability of altered cellular properties with in vitro incubation. For both normal control RBCs (A cells) and RBCs from patients with sickle cell anemia (S cells), cells with increased volume and markedly decreased intracellular hemoglobin concentration (65% to 70% of control) or with normal volume and moderately decreased hemoglobin concentration (80% to 85% of control) were prepared. These modifications were accomplished with hemoglobin yields ranging from 60% to 90%, depending on the diluent used, the cell type, and the intensity of treatment. For the same degree of inositol hexaphosphate (IHP) incorporation into A cells, as shown by the shift in oxygen half-saturation pressure (P50), diluent formulations with constant total osmolality but varying IHP concentration gave the same degree of hemoglobin loss per cell. Posttreatment cell size, however, ranged from slightly smaller than control to approximately 20% larger. On incubation, the larger cells returned toward normal size, whereas those with normal posttreatment size remained constant. S cells showed the same general changes with treatment and incubation but with greater variation. The treated S cells exhibited markedly reduced morphologic sickling on deoxygenation.