Bosentan is indicated for the treatment of pulmonary artery hypertension (PAH) by blocking the action of endothelin molecule (Ohlstein & Douglas, 1993; Vachiery & Simonneau, 2010; Granton et al., 2013) and it can prevent or reverse the associated histological change caused by elevated levels of ET1. This evidence concerns the gene EDN1 and pulmonary arterial hypertension.