In animal models, the loss of ACE2 was linked to decreased cardiac contractility and microcirculatory dysfunction and the administration of recombinant ACE2 was shown to inhibit the angiotensin II effects on the transforming growth factor (TGF)-β1 activation and collagen production and to attenuate whole aspects of pulmonary artery hypertension pathophysiology [47,48,49]. This evidence concerns the gene ACE2 and pulmonary arterial hypertension.