The heterogeneity of leukocyte rolling velocity and its relation to
leukocyte-endothelium adhesion and cell deformability.
Lipowsky, H. H., D. A. Scott, and J. S. Cartmell.
Bioengineering Program, Penn State University, University Park, PA,
16802
APStracts 2:0447H, 1995.
To explore the relationship between the rolling velocity of leukocytes
(VWBC) and wall shear rates (), measurements of VWBC were made along
the length of mesenteric venules (rat) in which a gradient in was
induced by compressing the venule with a blunted microprobe to form a
stenosis in which varied from 300 to 1500 sec-1. For individual WBCs
that rolled through the stenosis, VWBC was proportional to for its
entire range, in contrast to previous studies that have shown a
plateau in VWBC vs for the ensemble population. Comparisons of the
slope of VWBC vs for individual cells with ensemble values of VWBC/
obtained in the entrance region of the stenosis were made during
suffusion of the tissue with the chemoattractant n-formyl-methyl
-leucine-phenylalanine (FMLP), to increase WBC-EC adhesion and WBC
stiffness, or colchicine and cytochalasin B to increase WBC
deformability. Under control conditions, the slope of individual
cells was significantly 20% greater than VWBC/, whereas it was
significantly reduced by 48% during suffusion with FMLP. With
exposure to colchicine, the slope was 78% lower than VWBC/, and
compared to control was similar in magnitude to that obtained with
FMLP. Cytochalasin also reduced the slope by 22% compared to control
and 34% compared to VWBC/. The diminished slopes of VWBC vs were
consistent with published theoretical models that suggest a reduced
slope with increased strength of adhesion or WBC deformability. It is
thus concluded that the apparent plateau in VWBC vs arises due to the
heterogeneity of adhesive and/or deformability properties of the
ensemble population of circulating WBCs.
Received 27 June 1995; accepted in final form 12 September 1995.
APS Manuscript Number H589-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95