|
|
 Previous Article | Table of Contents | Next Article 
Role of plasma viscosity in platelet adhesion
HF van Breugel, PG de Groot, RM Heethaar and JJ Sixma
Department of Hematology, University Hospital Utrecht, The Netherlands.
Platelet adhesion to the vessel wall is initiated by transport of blood
platelets from the bulk flow to the wall. The process of diffusion and
convection of the platelets is affected by rheological conditions such as
well shear rate, red blood cell (RBC) deformability, and viscosity of the
medium. To study the effect of plasma viscosity on platelet adhesion,
perfusion experiments with a rectangular perfusion chamber were performed.
Reconstituted blood, consisting of washed platelets and washed RBCs, was
circulated through this chamber for 5 minutes at a wall shear rate of 300
s-1. Different albumin concentrations were made, to obtain different medium
viscosities (0.89 to 1.85 mPa.s). Platelet adhesion decreased with
increasing medium viscosity up to viscosities of 0.95 mPa.s, but increased
with medium viscosity above this value. Instead of human albumin solution,
different plasma viscosities were obtained by dilution of Waldenstrom
plasma with buffer. Plasma was depleted of fibronectin, which gave a final
plasma viscosity of 2.0 mPa.s, and was dialyzed against HEPES buffer and
subsequently diluted with the dialysis buffer in different fractions (0.89
to 2.00 mPa.s). Perfusions were performed over a purified von Willebrand
factor coating on glass, or over an endothelial cell matrix, preincubated
with von Willebrand factor. With both surfaces, platelet adhesion was
dependent on the plasma viscosity in a similar way: at low plasma
viscosities, adhesion was decreased with increasing plasma viscosity, while
at higher plasma viscosities, adhesion increased with plasma viscosity.
Adhesion values at higher plasma viscosity or at higher human albumin
concentrations could be explained by effects of the medium on the rigidity
of the RBCs, since platelet adhesion is known to be increased by enhanced
RBC rigidity. Effects of the medium on the deformability of the RBCs were
measured separately with the laser diffraction method. These experiments
confirmed that presence of human albumin or plasma in the measuring
suspension increased the rigidity of RBCs. To prevent influence of the
medium on the RBCs in perfusion experiments, the RBCs were fixated with
glutaraldehyde. Perfusion experiments with fixated RBCs in plasma over a
von Willebrand factor preincubated endothelial cell matrix, showed a
consequent decrease in adhesion with increasing plasma viscosity, according
to the diffusion theories, whereas the increase of adhesion at high plasma
viscosities was lacking. This suggests that the latter effect was entirely
due to increased transport of platelets by more rigid RBCs.
Volume 80,
Issue 4,
pp. 953-959,
08/15/1992
Copyright © 1992 by The American Society of Hematology
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
K. F. J. Ng, C. C. K. Lam, and L. C. Chan
In vivo effect of haemodilution with saline on coagulation: a randomized controlled trial{dagger}{ddagger}
Br. J. Anaesth.,
April 1, 2002;
88(4):
475 - 480.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. Junker, J. Heinrich, H. Ulbrich, H. Schulte, R. Schonfeld, E. Kohler, and G. Assmann
Relationship Between Plasma Viscosity and the Severity of Coronary Heart Disease
Arterioscler. Thromb. Vasc. Biol.,
June 1, 1998;
18(6):
870 - 875.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Nikol, T. Y. Huehns, R. Kiefmann, B. Hofling, and S. Nikol
Excessive Arterial Thrombus in Spherocytosis: A Case Report
Angiology,
August 1, 1997;
48(8):
743 - 748.
[Abstract]
[PDF]
|
|
|
|
|
|
|
S. C. Endenburg, L. Lindeboom-Blokzijl, J. J. Zwaginga, J. J. Sixma, and P. G. de Groot
Plasma Fibrinogen Inhibits Platelet Adhesion in Flowing Blood to Immobilized Fibrinogen
Arterioscler. Thromb. Vasc. Biol.,
May 1, 1996;
16(5):
633 - 638.
[Abstract]
[Full Text]
|
|
|
|
|
