Interplay between platelets and coagulation

Abstract

Haemostasis stops bleeding at the site of vascular injury and maintains the integrity of blood vessels through clot formation. This regulated physiological process consists of complex interactions between endothelial cells, platelets, von Willebrand factor and coagulation factors. Haemostasis is initiated by a damaged vessel wall, followed with a rapid adhesion, activation and aggregation of platelets to the exposed subendothelial extracellular matrix. At the same time, coagulation factors aggregate on the procoagulant surface of activated platelets to consolidate the platelet plug by forming a mesh of cross-linked fibrin. Platelets and coagulation mutually influence each other and there are strong indications that, thanks to the interplay between platelets and coagulation, haemostasis is far more effective than the two processes separately. Clinically this is relevant because impaired interaction between platelets and coagulation may result in bleeding complications, while excessive platelet-coagulation interaction induces a high thrombotic risk. In this review, platelets, coagulation factors and the complex interaction between them will be discussed in detail.

Keywords: Clinical disorders; Coagulation; Haemostasis; Platelet; Platelet-based coagulation.

Fig. 1

Interplay between platelets and coagulation. Part 1: Coagulation initiation and platelet activation. Part 2: Platelet-based amplification and propagation of coagulation and platelet activation and aggregation. Part 3: Inhibition of coagulation and platelet activation.

Fig. 2

Interaction of (anti)coagulation factors with key platelet membrane receptors. Coagulation factors interact with platelets by cleaving (red lines) the receptor directly (solid line) or indirectly (dashed line), or by binding (green line) to their respective receptors.