Purpose of review: The story of platelet activation is complex, involving many intertwined and overlapping pathways and processes that continue to expand in complexity. This review will cover some of the recent novel mediators and receptors identified to be important in platelet activation.
Recent findings: Many newly discovered platelet activators and receptors are not strong platelet agonists, but rather are important modifiers of platelet activation, and thus represent potentially novel targets to blunt, but not totally prevent, platelet activation and thrombus formation. The diversity of platelet activation mediators and receptors also expands as we learn more about the disease processes that are either initiated or accelerated by platelets. Although platelets are a unique cell type with a unique role in thrombosis, they share a surprising amount in common with the molecules and machinery present in synaptic termini and immune cells. Many of these secreted molecules have important roles in platelet activation.
Summary: Many newly identified platelet activators are weak agonists. These represent intriguing targets for platelet inhibitor development or shed light on the overlap between inflammation and thrombosis.