title: Effect of erythrocyte aggregation at pathological levels on NO/O2 transport in small arterioles.
abstract: This study examined the effects of red blood cell (RBC) aggregation at pathological levels on NO/O2 transport in small arterioles. Transient gas diffusion simulations were performed with in vivo cell-free layer (CFL) widths data obtained from arteriolar flows in the rat cremaster muscle. The CFL data were measured at physiological and pathological levels of aggregation under reduced flow conditions (pseudoshear rate = 31.4 ± 10.5 s-1). Our results showed that the mean peak NO concentration significantly decreased with increasing the aggregation level from non-aggregating to normal-aggregating (P < 0.05) and to hyper-aggregating (P < 0.01) conditions. In contrast, the partial O2 pressure (PO2) in pathological aggregating conditions significantly increased from those under non-aggregating (P < 0.001) and normal-aggregating (P < 0.05) conditions. Although the NO scavenging by RBCs could be impaired with a thicker CFL at higher levels of aggregation, the overall decrease in NO production due to reduction of wall shear stress with the thicker CFL dominantly limited the NO availability in tissue. On the other hand, the O2 availability in tissue increased due to the relatively high core hematocrit in the blood lumen with the thicker CFL.
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore Department of Biomedical Engineering, Yonsei University, Wonju, Gangwon, Korea.
authors.forename: Seungkwan
authors.initials: S
authors.lastname: Cho
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore.
authors.forename: Bumseok
authors.initials: B
authors.lastname: Namgung
authors.affiliation: Department of Biomedical Engineering, Yonsei University, Wonju, Gangwon, Korea.
authors.forename: Han Sung
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore.
authors.forename: Hwa Liang
authors.initials: HL
authors.lastname: Leo
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore Department of Surgery, National University of Singapore, Singapore, Singapore.
authors.forename: Sangho
authors.initials: S
authors.lastname: Kim
mesh_terms: D001160:Arterioles / Q000502:physiology*; D004903:Erythrocyte Aggregation / Q000502:physiology*; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism*
chemical_list: D009569:Nitric Oxide
keywords: Hemodynamics; gas diffusion; microcirculation; plasma layer