Summary of platelet functions that can affect I/R injury. Following I/R, activated platelets can promote I/R injury by interacting with VWF, binding to exposed subendothelial collagen, secreting granules and recruiting/activating leukocytes, especially neutrophils, exposing phosphatidylserine (PS; which enhances thrombin generation), and releasing platelet microparticles (PMPs; which can affect other cells by delivery of microRNAs) to enhance tissue death. PNA, platelet-neutrophil aggregate.