EDN1 and idiopathic pulmonary fibrosis: Expression levels of pro-fibrotic growth factors such as transforming growth factor beta 1 (TGFB1), connective tissue growth factor (CTGF), endothelin 1 (ET-1), and platelet derived growth factor (PDGF) among other mediators have all been implicated in the pathogenesis of IPF [2, 5, 11–15].