Degradation of fibrinogen by tissue plasminogen activator. Consequences for fibrin polymerization

In patients treated with tissue plasminogen activator (t-PA), there was a marked increase in concentration of fibrinopeptide A (fpA). The purpose of this study was to analyse the activation of coagulation in plasma treated in vitro by pharmacological doses of t-PA. From our results, it appears that fpA release due to direct interaction of fibrinogen with t-PA, in the absence of plasminogen, is very low and not observed with pharmacological doses of t-PA. In contrast in the presence of plasminogen, the release of fpA is much higher and induces fibrin formation concomitantly to fibrinogen degradation.