Effects of a perfluoro erythrocyte substitute on platelets in vitro and in vivo
Colman, R.W.; Chang, L.K.; Mukherji, B.; Sloviter, H.A.
Journal of Laboratory and Clinical Medicine 95(4): 553-562
1980
ISSN/ISBN: 0022-2143 PMID: 6444655 Document Number: 165857
Emulsified perfluoro compounds, which were proposed as erythrocyte substitutes, produced thrombocytopenia and affected blood coagulation factors when injected i.v. in animals. Shape change in human platelets induced in vitro by ADP or thrombin was inhibited by an emulsion, in an albumin solution, of FC-80. Decrease in the rate of shape change was proportional to the concentration of FC-80, with half-inhibition found at 0.2%, a concentration less than used in vivo. Higher concentrations of FC-80 (0.5-1.3%) inhibited ADP-induced platelet aggregation, increasing the threshold concentration 100-fold. FC-80 did not affect platelet secretion of 14C-serotonin and ATP induced by aggregating agents. Release of .beta.-glucuronidase was not induced by FC-80 in concentrations as high as 1.3%. FC-80 did not affect aggregation or release induced by sodium arachidonate (0.5 mM), indicating a lack of effect on prostaglandin synthesis. Emulsifying FC-80 in a cholesterol-lecithin medium, instead of in albumin, abolished inhibition of platelet aggregation but did not reverse the inhibitory effect on shape change. In rats, platelet counts decreased within 5 min after infusion of FC-80 dispersed in albumin, and 2 h after infusion the decrease in platelet count varied from 34-74% of initial levels. Rats injected with FC-80 dispersed in cholesterol-lecithin showed no significant change in platelet count in the 2 h after infusion. These results in vitro and in vivo suggest that coating the fluorochemical particles with lipid alters the surface-modifying properties of FC-80.