title: Influence of calcium permeabilization and membrane-attached hemoglobin on erythrocyte deformability.
abstract: The present study was designed to evaluate the influence of intracellular calcium [Ca]i regulated membrane attached hemoglobin (Hbm) on the deformability of human RBC and ghosts. [Ca]i of RBC was elevated via the ionophore A23187 (10 microM); the deformability of RBC and resealed ghosts was determined via measuring RBC and ghost transit times through 5 microns diameter pores with the Cell Transit Analyzer (CTA). Salient results included: (1) significantly increased RBC levels of Hbm following ionophore treatment; (2) elevated Hbm with increasing lysing medium calcium concentration (0-5 mM); (3) decreased deformability of both intact RBC and ghosts with increasing Hbm and significant (P less than 0.02 or better) linear relationships between Hbm and RBC or ghost transit times; and (4) an increased sensitivity to ionophore treatment/membrane attached hemoglobin for the higher percentiles of the CTA transit time distribution (i.e., for more rigid subpopulations). Our results thus indicate that calcium-induced interaction of hemoglobin with the RBC membrane produces cellular rheological changes; in addition, they demonstrate the usefulness of the CTA system in measuring both average RBC rheologic behavior and the distribution of cellular rheologic properties within an erythrocyte population.
authors.affiliation: Department of Physiology and Biophysics, University of Southern California, School of Medicine, Los Angeles 90033.
authors.forename: E
authors.initials: E
authors.lastname: Friederichs
authors.forename: R A
authors.initials: RA
authors.lastname: Farley
authors.forename: H J
authors.initials: HJ
authors.lastname: Meiselman
mesh_terms: D000328:Adult; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000493:pharmacokinetics* / Q000502:physiology; D002463:Cell Membrane Permeability; D002469:Cell Separation; D003599:Cytoskeleton / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D004907:Erythrocyte Deformability / Q000187:drug effects / Q000502:physiology*; D004910:Erythrocyte Membrane / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D004912:Erythrocytes / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D005374:Filtration / Q000379:methods; D006454:Hemoglobins / Q000032:analysis / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D012212:Rheology
chemical_list: D006454:Hemoglobins; D000001:Calcimycin; D002118:Calcium