AJP - Heart and Circulatory Physiology, Vol 259, Issue 5 1527-H1532, Copyright © 1990 by American Physiological Society
Enhancement of red cell washout from blood clots by alteration of gel pore size and red cell flexibility
M. E. Carr Jr and Y. Hauge
Department of Pathology, Medical College of Virginia, Richmond.
Plasma clots formed in the presence of erythrocytes have pores large enough
to allow significant perfusion induced washout of red cells. Erythrocyte
washout is a function of gel pore size and erythrocyte flexibility. This
study evaluated the possibility of increasing cell washout by enhancing gel
pore size and/or erythrocyte flexibility. Addition of increasing
concentrations of Dextran 40 resulted in gels composed of large fibers with
large intervening pores. Gel fiber mass-to-length ratios increased from 2.6
to 8.1 x 10(13) Da/cm as Dextran 40 concentration increased from 0 to 12
mg/ml. Over the same dextran concentration range, perfusion measurements
revealed an increase in gel pore diameter from 1.4 to 3.5 x 10(-4) cm and
an increase in erythrocyte washout from 8.2 to 30.4% during a 1.5 gel
volume exchange. Pentoxifylline was added to blood to enhance erythrocyte
flexibility. Whereas turbidity measurements indicated minimal direct impact
of pentoxifylline (50 micrograms/ml) on fibrin assembly or structure,
perfusion measurements indicated an increase in erythrocyte washout from
8.1 to 13.4% after a 1.5 gel volume exchange. Efforts to evaluate
pentoxifylline effects at higher concentrations were hampered by decreased
adhesion of the gel to the sides of the perfusion chamber. These results
indicate that it may be possible to enhance erythrocyte washout and thereby
increase diffusion and perfusion of materials through in situ clots.
