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A Hematocrit‐Dependent Red Blood Cell Exclusion Zone (“No Fly Zone”) is Present at the Wall of Arterioles
Author(s) -
Yalcin Ozlem,
Jivani Manoj,
Intaglietta Marcos,
Johnson Paul
Publication year - 2010
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.24.1_supplement.974.8
Subject(s) - hematocrit , chemistry , microcirculation , red cell , biophysics , red blood cell , blood flow , anatomy , medicine , biology , biochemistry
A red blood cell (RBC) exclusion zone at the vessel wall has been reported in capillaries and in arterioles during red cell flow. In the current study we found a hematocrit‐dependent RBC exclusion zone between the vascular wall and flowing RBCs in 30–40 μm arterioles. The width of this “no fly zone” decreased from 2.0 μm at a systemic hematocrit (Hct sys ) of 20% to a value of 1.0 to 1.1μm over a wide Hct sys range of 30 to 60%. However, the zone width fell to 0.47μm at 65% and to zero at 70, and 75% Hct sys ). Also 16 and 22% of the RBCs nearest the wall were found at the wall at Hct sys levels of 70 and 75% but none at lower hematocrits. An exclusion layer of about 1 μm consisting of an endothelial surface layer (ESL) and a lubrication layer has been reported in capillaries. An ESL of about 1 μm thickness has been suggested in arterioles of dimensions similar to ours. Our findings at 30% Hct sys and above could be due to an ESL with structural properties that effectively resist the centrifugal forces acting on the most peripheral RBCs in the 30–60% Hct sys range but are overcome by these forces at higher Hct sys . In the range 20–30% Hct sys axial migration tendencies rather than the ESL may provide an outer limit to RBC location relative to the vascular wall.