Platelet-mediated vascular dysfunction during acute lung injury

Context: Platelets have significant roles in initiating and mediating reduced alveolar blood flow, microvascular leak, and ventilation/perfusion mismatch caused by metabolic changes and altered signal transduction caused by ischemia-reperfusion. Objective: This review focuses on platelet mechanisms of vascular dysfunction in the lung and presents a hypothesis for interplay between platelet activation, endothelial damage and fibrinogen. The purpose is to discuss current knowledge regarding mechanisms of platelet-mediated endothelial injury and implications for new strategies to treat vascular dysfunction associated with acute lung injury (ALI). Methods: Literature from a number of fields was searched using Medline and Google Scholar. Results: Activated platelets contribute to redox imbalance through reactive oxygen species production, pro-leak molecules such as PAF and serotonin, and recruitment of inflammatory cytokines and leukocytes to the damaged endothelium. Conclusion: Platelets are a critical component of pulmonary ALI, acting in conjunction with fibrinogen to mediate endothelial damage through multiple signal transduction pathways.