Hydroxychloroquine inhibits hemolysis-induced arterial thrombosis ex vivo and improves lung perfusion in hemin-treated mice

Abstract

BackgroundFree labile hemin acts in a damage-associated molecular pattern during acute and chronic hemolysis and muscle injury, supporting platelet activation and thrombosis. ObjectivesTo investigate the antithrombotic potential of hydroxychloroquine in hemolysis-induced arterial thrombosis ex vivo, hemin-induced platelet activation, ferric chloride–induced arterial thrombosis, and lung perfusion following hemin injection in mice. ResultsErythrocyte lysis and endothelial cell activation cooperatively supported platelet aggregation and thrombosis at arterial shear stress. This thrombotic effect was reversed by hydroxychloroquine. In a purified system, hydroxychloroquine inhibited platelet build-up on immobilized von Willebrand factor in hemolyzed blood without altering initial platelet recruitment. Hydroxychloroquine inhibited hemin-induced platelet activation and phosphatidylserine exposure independently of reactive oxygen species generation. In the presence of hemin, hydroxychloroquine did not alter glycoprotein VI shedding but reduced C-type-lectin-like-2 expression on platelets. In vivo, hydroxychloroquine reversed pulmonary perfusion decline induced by exogenous administration of hemin. In arterial thrombosis models, hydroxychloroquine inhibited ferric-chloride–induced thrombosis in the carotid artery and reduced von Willebrand factor accumulation in the thrombi. ConclusionHydroxychloroquine inhibited hemolysis-induced arterial thrombosis ex vivo and improved pulmonary perfusion in hemin-treated mice, supporting a potential benefit of its use as an adjuvant therapy in hemolytic diseases to limit arterial thrombosis and to improve organ perfusion.