THE ROLE OF PLATELET P2Y₁₂ IN INFLAMMATION

Abstract Inflammation is a complex pathophysiological process underlying many clinical conditions. Platelets contribute to the thrombo‐inflammatory response. Platelet P2Y 12 receptors amplify platelet activation, potentiating platelet aggregation, degranulation and shape change. The contents of platelet alpha granules, in particular, act directly on leucocytes, including mediating platelet–leucocyte aggregation and activation via platelet P‐selectin. Much evidence for the role of platelet P2Y 12 receptors in inflammation comes from studies using antagonists of these receptors, such as the thienopyridines clopidogrel and prasugrel, and the cyclopentyltriazolopyrimidine ticagrelor, in animal and human experimental models. These suggest that antagonism of P2Y 12 receptors decreases markers of inflammation with some evidence that this reduces incidence of adverse clinical sequelae during inflammatory conditions. Interpretation is complicated by pleiotropic effects such as those of the thienopyridines on circulating leucocyte numbers and of ticagrelor on adenosine reuptake. The available evidence suggests that P2Y 12 receptors are prominent mediators of inflammation and P2Y 12 receptor antagonism as a potentially powerful strategy in a broad range of inflammatory conditions.