Sickling as a function of oxygen delivery: effect of simulated transfusions of stored, fresh and inositol-hexaphosphate-loaded (low affinity) red cells.
Low oxygen affinity red cells were prepared by incorporating inositol hexaphosphate (IHP) into red blood cells (rbc) by means of a liposomal transport system. The effect of in vitro simulated exchange transfusions on sickling was studied with buffered red cell suspensions containing 50% SS cells and 50% test cells. Test rbc were either stored cells with high oxygen affinity, fresh cells with normal affinity or IHP-loaded cells with decreased affinity. Oxygen equilibrium curves and percentage sickling as a function of PO2 were determined and the data analyzed in terms of percentage sickling as a function of oxygen delivery. Our simplified analysis shows that simulated exchange transfusion with stored and, to a lesser extent even with fresh blood, results in a decreased venous PO2 and increased sickling of the remaining SS cells. In contrast, transfusion with IHP-loaded cells results in higher venous PO2 values and less sickling throughout the range of oxygen delivery. Thus, the transfusion of IHP-loaded cells may result in less sickling of the remaining SS cells in addition to the normal dilutional effect.
D019794:2,3-Diphosphoglycerate; D000755:Anemia, Sickle Cell / Q000097:blood* / Q000628:therapy; D004163:Diphosphoglyceric Acids / Q000097:blood; D004913:Erythrocytes, Abnormal / Q000378:metabolism*; D005078:Exchange Transfusion, Whole Blood; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D010100:Oxygen / Q000097:blood*; D010833:Phytic Acid / Q000097:blood*
D004163:Diphosphoglyceric Acids; D006454:Hemoglobins; D019794:2,3-Diphosphoglycerate; D010833:Phytic Acid; D010100:Oxygen