EDN1 and idiopathic pulmonary fibrosis: Additionally, increased expression of ET-1 was observed in lung tissues from patients with idiopathic pulmonary fibrosis (IPF) [4], and ET-1 was reported to recruit and differentiate lung fibroblasts into myofibroblasts, induce alveolar epithelial mesenchymal transition (EMT), and promote extracellular matrix (ECM) production [5,6,7].