Red blood cell deformability influences platelets--vessel wall interaction
in flowing blood
PA Aarts, RM Heethaar and JJ Sixma
Hematocrit and red cell size are important factors for the transport of
blood platelets toward subendothelium in flowing blood. We report that red
cell deformability also influences platelet transport. Red cell
deformability was estimated with Couette-flow viscosimetry at a shear rate
of 130 s-1 and expressed as a 'T' factor--a dimensionless parameter
relating the relative viscosity and the hematocrit derived from the
relationship: T = (1 - mu -0.4 rel)/H, where mu rel is the relative
viscosity and H is the hematocrit. The normal value of T was within a
narrow range (0.91 +/- 0.02). Treatment of normal red cells with
isoxsuprine and chlorpromazine caused decreased rigidity and decreased T.
Cholesterol loading and treatment with diamide increased rigidity and
increased T. In vitro perfusion experiments in an annular perfusion system
with everted human umbilical arteries were performed with perfusates to
which such treated red blood cells were added to investigate their
influence on platelet adherence to artery subendothelium. Platelet
adherence was well correlated with red cell rigidity, with increased
adherence at increased rigidity and vice versa. A change in T of 0.10
corresponded to a change in platelet adherence of approximately 50%. These
effects were more pronounced at a wall shear rate of 1,800 s-1 than at 300
s-1.
Volume 64,
Issue 6,
pp. 1228-1233,
12/01/1984
Copyright © 1984 by The American Society of Hematology
