Flatt Christine, Mitchell Sheona, Yipp Bryan, Looareesuwan Sornchai, Ho May
Department of Microbiology and Infectious Diseases and Immunology Research Group, University of Calgary, Calgary, Alberta, Canada.
Am J Trop Med Hyg. 2005 Jun;72(6):660-5.
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.
