EDN1 and idiopathic pulmonary arterial hypertension: The damage of vascular endothelial function induced by increased plasma levels of ET-1 is one of the key factors in the pathogenesis of Idiopathic Pulmonary Arterial Hypertension and, although this is not part of the scope of our review, it is useful to remember that the use of ET receptor antagonists in this setting has greatly helped in understanding the interaction between ET and NO in humans [18].