Abstract
This article represents a republication of an article originally published in STH
in 2005. This republication is to help celebrate 50 years of publishing for STH. The
original abstract follows.
Platelets are specialized blood cells that play central roles in physiologic and pathologic
processes of hemostasis, inflammation, tumor metastasis, wound healing, and host defense.
Activation of platelets is crucial for platelet function that includes a complex interplay
of adhesion and signaling molecules. This article gives an overview of the activation
processes involved in primary and secondary hemostasis, for example, platelet adhesion,
platelet secretion, platelet aggregation, microvesicle formation, and clot retraction/stabilization.
In addition, activated platelets are predominantly involved in cross-talk to other
blood and vascular cells. Stimulated “sticky” platelets enable recruitment of leukocytes
at sites of vascular injury under high shear conditions. Platelet-derived microparticles
as well as soluble adhesion molecules, sP-selectin and sCD40L, shed from the surface
of activated platelets, are capable of activating, in turn, leukocytes and endothelial
cells. This article focuses further on the new view of receptor-mediated thrombin
generation of human platelets, necessary for the formation of a stable platelet–fibrin
clot during secondary hemostasis. Finally, special emphasis is placed on important
stimulatory and inhibitory signaling pathways that modulate platelet function.
Keywords
platelet activation - platelet adhesion - platelet aggregation - procoagulant activity
- thrombin generation
