title: Attenuation of cytoadherence of Plasmodium falciparum to microvascular endothelium under flow by hemodilution.
abstract: The cytoadherence of Plasmodium falciparum-infected erythrocytes (IRBCs) to endothelium is mediated by adhesion molecules within the physical constraints of a viscous fluid containing mostly erythrocytes. The volume fraction of erythrocytes (hematocrit) and their physical properties, such as deformability, are important properties of blood that affect cell recruitment to the vascular wall. In the present study, we examined the effect of hematocrit on IRBC rolling and adhesion on human microvascular endothelial cells in a flow chamber system in vitro. We found hematocrit to be a major determinant of IRBC/endothelial cell interactions. There was a 5-fold and 12-fold increase in IRBC rolling and adhesion, respectively, when hematocrit increased from 10% to 30%, as a result of changes in shear rate. Similar effects were seen in the presence of less deformable erythrocytes, serum proteins, and on endothelium stimulated with tumor necrosis factor-alpha. The results indicate that hemorheologic variations are an important determinant of the degree of cytoadherence.
authors.affiliation: Department of Microbiology and Infectious Diseases and Immunology Research Group, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Christine
authors.initials: C
authors.lastname: Flatt
authors.forename: Sheona
authors.initials: S
authors.lastname: Mitchell
authors.forename: Bryan
authors.initials: B
authors.lastname: Yipp
authors.forename: Sornchai
authors.initials: S
authors.lastname: Looareesuwan
authors.forename: May
authors.initials: M
authors.lastname: Ho
mesh_terms: D000818:Animals; D001769:Blood; D002196:Capillaries / Q000187:drug effects / Q000469:parasitology*; D002448:Cell Adhesion; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects / Q000469:parasitology*; D006400:Hematocrit; D006801:Humans; D010963:Plasmodium falciparum / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha