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The dependence of cell‐free layer thickness in arterioles on systemic hematocrit level
Author(s) -
Yalcin Ozlem,
Choi Christine,
Chatpun Surapong,
Intaglietta Marcos,
Johnson Paul
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.949.7
Subject(s) - hematocrit , cremaster muscle , chemistry , red cell , hemoconcentration , microcirculation , materials science , medicine
Axial migration of red cells in microcirculatory vessels leads to formation of a cell‐free layer (CFL) near the vessel wall. CFL width may be physiologically important in determining hydrodynamic resistance and of NO scavenging by the red cell column, especially in arterioles. It would be expected that the degree of axial migration and width of the CFL would decrease as hematocrit (hct) increases. Our purpose is to determine the hct dependence of CFL width with hemoconcentration and hemodilution. We measured the CFL width in arterioles (20‐55 μm i.d.) in rat cremaster muscle. Dextran 500 was infused to elevate erythrocyte aggregation to normal human levels. Systemic hct was increased stepwise from 40% to 45, 50 and 55% in one group and decreased to 35 and 30% in another group. We measured the CFL thickness and its variations with a high speed video camera and custom built software. To check the performance of this automated method, manual measurements were performed. A 50% increase in hct level (30% to 45%) led to a significant decrease in CFL width (5.15 ± 0.78 μm to 2.69 ± 0.17 μm) (r=‐0.54, p<0.01) while a further 23% increase (45% to 55%) had no effect (2.69 ± 0.17 μm to 2.66 ± 0.16 µm). The variations showed a similar trend. The dependence of CFL width on hct parallels that reported previously for tube hct. Another implication of our results is that NO scavenging may have an inverse relationship with systemic hct.