title: Influence of erythrocyte aggregation at pathological levels on cell-free marginal layer in a narrow circular tube.
abstract: Human red blood cells (RBCs) were perfused in a circular micro-tube (inner diameter of 25 μm) to examine the dynamic changes of cell-free marginal region at both physiological (normal) and pathophysiological (hyper) levels of RBC aggregation. The cell-free area (CFA) was measured to provide additional information on the cell-free layer (CFL) width changes in space and time domains. A prominent enhancement in the mean CFL width was found in hyper-aggregating conditions as compared to that in non-aggregating conditions (P <  0.001). The frequent contacts between RBC and the tube wall were observed and the contact frequency was greatly decreased when the aggregation level was increased from none to normal (P <  0.05) and to hyper (P <  0.001) levels. In addition, the enhanced aggregation from none to hyper levels significantly enlarged the CFA (P <  0.01). We concluded that the RBC aggregation at pathophysiological levels could promote not only the CFL width (one-dimensional parameter) but also the spatiotemporal variation of CFA (two-dimensional parameter).
authors.affiliation: Department of Biomedical Engineering and Department of Surgery, National University of Singapore, Singapore.
authors.forename: Bumseok
authors.initials: B
authors.lastname: Namgung
authors.affiliation: Department of Chemistry, School of Medicine, Nara Medical University, Nara, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Sakai
authors.affiliation: Department of Biomedical Engineering and Department of Surgery, National University of Singapore, Singapore.
authors.forename: Sangho
authors.initials: S
authors.lastname: Kim
mesh_terms: D004903:Erythrocyte Aggregation / Q000276:immunology*; D004906:Erythrocyte Count / Q000379:methods*; D004912:Erythrocytes / Q000276:immunology*; D006439:Hemodynamics; D006801:Humans; D008833:Microcirculation
keywords: Plasma layer; hemodynamic; microcirculation; red blood cell