title: Direct platelet-fibrin interaction that does not require platelet activation.
abstract: Interactions between platelets and fibrin are important in hemostasis but often confused with platelet-fibrinogen interactions. Fibrin solubilized in NaBr-acetic acid formed polymers in neutral pH buffers. A stirred mixture of solubilized fibrin and washed human platelets at neutral pH range showed drastic reduction in turbidity and concomitant platelet adhesion onto newly formed fibrin strands. Optimally, more than 99% of platelets could be associated with fibrin, whereas only 3% of erythrocytes were trapped in the fibrin network under similar conditions. This platelet-fibrin interaction was fibrin concentration dependent and polymerization stage dependent. It preceded any detectable platelet release of serotonin. Gly-Pro-Arg-Pro (250 times in excess) retarded the kinetics of fibrin polymerization as well as that of platelet-fibrin interaction. However, factors affecting platelet activation showed little effect on platelet-fibrin interaction. Our results support the existence of a platelet-fibrin interaction that does not require platelet activation.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000527:Alprostadil / Q000494:pharmacology; D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism*; D004533:Egtazic Acid / Q000494:pharmacology; D005337:Fibrin / Q000378:metabolism*; D006531:HEPES; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009391:Nephelometry and Turbidimetry; D009842:Oligopeptides / Q000494:pharmacology; D010974:Platelet Aggregation; D011108:Polymers; D012701:Serotonin / Q000097:blood
chemical_list: D009842:Oligopeptides; D011108:Polymers; D012701:Serotonin; D004533:Egtazic Acid; D000244:Adenosine Diphosphate; C034585:glycyl-prolyl-arginyl-proline; D005337:Fibrin; D000527:Alprostadil; D001241:Aspirin; D006531:HEPES