A novel method to quantify fibrin–fibrin and fibrin–α2-antiplasmin cross-links in thrombi formed from human trauma patient plasma

Abstract

BackgroundThe widespread use of the antifibrinolytic agent, tranexamic acid (TXA), interferes with the quantification of fibrinolysis by dynamic laboratory assays such as clot lysis, making it difficult to measure fibrinolysis in many trauma patients. At the final stage of coagulation, factor (F)XIIIa catalyzes the formation of fibrin–fibrin and fibrin–α2-antiplasmin (α2AP) cross-links, which increases clot mechanical strength and resistance to fibrinolysis. ObjectivesHere, we developed a method to quantify fibrin–fibrin and fibrin–α2AP cross-links that avoids the challenges posed by TXA in determining fibrinolytic resistance in conventional assays. MethodsFibrinogen alpha (FGA) chain (FGA–FGA), fibrinogen gamma (FGG) chain (FGG–FGG), and FGA–α2AP cross-links were quantified using liquid chromatography–mass spectrometry (LC–MS) and parallel reaction monitoring in paired plasma samples from trauma patients prefibrinogen and postfibrinogen replacement. Differences in the abundance of cross-links in trauma patients receiving cryoprecipitate (cryo) or fibrinogen concentrate (Fg-C) were analyzed. ResultsThe abundance of cross-links was significantly increased in trauma patients postcryo, but not Fg-C transfusion (P < .0001). The abundance of cross-links was positively correlated with the toughness of individual fibrin fibers, the peak thrombin concentration, and FXIII antigen (P < .05). ConclusionWe have developed a novel method that allows us to quantify fibrin cross-links in trauma patients who have received TXA, providing an indirect measure of fibrinolytic resistance. Using this novel approach, we have avoided the effect of TXA and shown that cryo increases fibrin–fibrin and fibrin–α2AP cross-linking when compared with Fg-C, highlighting the importance of FXIII in clot formation and stability in trauma patients.