EDN1 and pulmonary fibrosis: In addition, the activated platelets and endothelial cells could secrete profibrotic mediators, inducing tumor growth factor 1 (TGF-1), serotonin, endothelin-1 (ET-1), and vesicles, which would further amplify the endothelial damage, lung fibrosis, and evolution of SSc into PH [18,19,20,21].