Fibrin monomer and platelet aggregation in vitro and in vivo.

Abstract

Summary. The effect of fibrin monomer or fibrinogen‐fibrin monomer complexes (FFMC) on platelet aggregation was studied in vitro and in vivo. FFMC produced by limited action of thrombin in vitro did not cause spontaneous platelet aggregation and neither accelerated nor inhibited platelet aggregation induced by ADP or collagen. If FFMC were converted to gels by treatment with ethanol, platelets aggregated spontaneously. When purified rabbit fibrin monomer was infused into rabbits pretreated with heparin to block the intravascular generation of thrombin, platelet counts did not decrease significantly, indicating the lack of a plateletaggregating effect of FFMC. It is concluded that FFMC, derived from thrombin action on fibrinogen, do not initiate or accelerate platelet aggregation.