Effect of inositol hexaphosphate-loaded red blood cells (RBCs) on the rheology of sickle RBCs

BACKGROUND: The recent in vitro demonstration that inositol hexaphosphateloaded red blood cells (IHP-RBCs) may reduce the risks of sickling of sickle RBCs (SS RBCs) exposed to hypoxia make these modified RBCs potentially useful in transfused sickle cell anemia (SCA) patients. STUDY DESIGN AND METHODS: Hemorheologic properties of IHP-RBCs, normal RBCs (AA RBCs), SS RBCs, SS RBCsplusAA RBCs, and SS RBCs plus IHP-RBCs were compared under normoxia and/or after hypoxic challenges. RESULTS: Although IHP-RBCs have reduced deformability compared with SS RBCs or AA RBCs, IHP-RBCs exhibited lower aggregability than AA RBCs and SS RBCs and, when mixed with SS RBCs, the aggregation level was below the one of SS RBCs alone or SS RBCsplusAA RBCs. Blood viscosity of SS RBC plus IHP-RBC suspension was lower than the viscosity of SS RBCs alone and greater than viscosity of SS RBCsplusAA RBCs. The hypoxic challenge was detrimental for deformability and viscosity of SS RBCs alone or SSplusAA RBC suspension but not for SSplusIHP-RBC suspension. CONCLUSION: Our results support the fact that IHP-RBCs could be useful in SCA by decreasing RBC aggregation and blunting the adverse effects of hypoxia on RBC deformability and blood viscosity.