Fig. 2.

Cellular mediators of fibrinolysis inhibition. This figure represents a schematic of the potential cellular mediators of decreasing fibrinolytic activity. Local tissue injury exposes platelet activators for aggregation. Based on the level of activation of platelet activity, these platelets form an internal core of tightly bound platelets and release antifibrinolytic proteins, microparticles, and thrombin. This platelet core is buffered by a platelet shell that also incorporates neutrophils that can become activated and release neutrophil extracellular traps, creating a more fibrinolytic resistant clot. The platelet core thrombin release also cleaves PAI-1 from the extracellular matrix, in addition to stimulating PAI-1 expression in underlying vascular smooth muscle cells. PAI-1, plasminogen activator inhibitor 1.