Similarly to the effects of elafin, the synthetic activator of ACE2, XNT (1-[(2-dimethylamino) ethylamino]-4-(hydroxymethyl)-7-[(4-methylphenyl) sulfonyl oxy]-9H-xanthene-9-one) restricts pathogenic progression of monocrotaline-treated PAH rats (Ferreira et al., 2009). Here, ACE2 is linked to pulmonary arterial hypertension.