COVID-19 infection is associated with a broad spectrum of presentations, but alveolar capillary microthrombi have been described as a common finding in COVID-19 patients, appearing as a consequence of a severe endothelial injury with endothelial cell membrane disruption. These observations clearly point to the identification of a COVID-19-associated coagulopathy, which may contribute to thrombosis, multi-organ damage, and cause of severity and fatality. One significant finding that emerges in prothrombotic abnormalities observed in COVID-19 patients is that the coagulation alterations are mainly mediated by the activation of platelets and intrinsically related to viral-mediated endothelial inflammation. Beyond the well-known role in hemostasis, the ability of platelets to also release various potent cytokines and chemokines has elevated these small cells from simple cell fragments to crucial modulators in the blood, including their inflammatory functions, that have a large influence on the immune response during infectious disease. Indeed, platelets are involved in the pathogenesis of acute lung injury also by promoting NET formation and affecting vascular permeability. Specifically, the deposition by activated platelets of the chemokine platelet factor 4 at sites of inflammation promotes adhesion of neutrophils on endothelial cells and thrombogenesis, and it seems deeply involved in the phenomenon of vaccine-induced thrombocytopenia and thrombosis. Importantly, the hyperactivated platelet phenotype along with evidence of cytokine storm, high levels of P-selectin, D-dimer, and, on the other hand, decreased levels of fibrinogen, von Willebrand factor, and thrombocytopenia may be considered suitable biomarkers that distinguish the late stage of COVID-19 progression in critically ill patients.
【저자키워드】 COVID-19, SARS-CoV-2, Inflammation, platelet activation, thrombosis, immunothrombosis, 【초록키워드】 Cytokine storm, immune response, Biomarker, Pathogenesis, severity, neutrophil, D-dimer, cytokine, vascular permeability, Infectious disease, chemokine, acute lung injury, P-selectin, Coagulation, Coagulopathy, Hemostasis, COVID-19 infection, von Willebrand factor, Platelet, phenotype, membrane, fibrinogen, endothelial injury, critically ill patients, COVID-19 patients, Blood, fatality, Endothelial cell, Evidence, Inflammatory, COVID-19 patient, Multi-organ damage, microthrombi, observation, COVID-19 progression, endothelial, alteration, functions, late stage, abnormality, alveolar capillary, NET, Cell, prothrombotic, described, involved, elevated, activated, contribute, promote, affecting, intrinsically, activation of platelet, cell fragment, sites of inflammation, 【제목키워드】 focus,