title: Shape matters: the effect of red blood cell shape on perfusion of an artificial microvascular network.
abstract: BACKGROUND
  The shape of human red blood cells (RBCs) deteriorates progressively throughout hypothermic storage, with echinocytosis being the most prevalent pathway of this morphologic lesion. As a result, each unit of stored blood contains a heterogeneous mixture of cells in various stages of echinocytosis and normal discocytes. Here we studied how the change in shape of RBCs following along the path of the echinocytic transformation affects perfusion of an artificial microvascular network (AMVN).
  
  
  METHODS
  Blood samples were obtained from healthy consenting volunteers. RBCs were leukoreduced, resuspended in saline, and treated with various concentrations of sodium salicylate to induce shape changes approximating the stages of echinocytosis experienced by RBCs during hypothermic storage (e.g., discocyte, echinocyte I, echinocyte II, echinocyte III, spheroechinocyte, and spherocyte). The AMVN perfusion rate was measured for 40% hematocrit suspensions of RBCs with different shapes.
  
  
  RESULTS
  The AMVN perfusion rates for RBCs with discocyte and echinocyte I shapes were similar, but there was a significant decline in the AMVN perfusion rate between RBCs with shapes approximating each subsequent stage of echinocytosis. The difference in AMVN perfusion between discocytes and spherocytes (the last stage of the echinocytic transformation) was 34%.
  
  
  CONCLUSIONS
  The change in shape of RBCs from normal discocytes progressively through various stages of echinocytosis to spherocytes produced a substantial decline in the ability of these cells to perfuse an AMVN. Echinocytosis induced by hypothermic storage could therefore be responsible for a similarly substantial impairment of deformability previously observed for stored RBCs.
authors.affiliation: Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, Texas.
authors.forename: Nathaniel Z
authors.initials: NZ
authors.lastname: Piety
authors.affiliation: Department of Internal Medicine, Kantonsspital Graubünden, Chur, Switzerland.
authors.forename: Walter H
authors.initials: WH
authors.lastname: Reinhart
authors.affiliation: Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, Texas.
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Pourreau
authors.affiliation: Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, Texas.
authors.forename: Rajaa
authors.initials: R
authors.lastname: Abidi
authors.affiliation: Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, Texas.
authors.forename: Sergey S
authors.initials: SS
authors.lastname: Shevkoplyas
mesh_terms: D000818:Animals; D001809:Blood Viscosity / Q000502:physiology; D048430:Cell Shape; D004907:Erythrocyte Deformability / Q000502:physiology; D004912:Erythrocytes / Q000166:cytology* / Q000502:physiology; D006801:Humans; D055806:Microvessels / Q000502:physiology*; D010477:Perfusion / Q000295:instrumentation / Q000379:methods; D051381:Rats