In a model of PAH [Pyr1]apelin-13 (Falcão-Pires et al., 2009; Maguire et al., 2009) and ELA-32 (Yang et al., 2017) prevented disease onset, however, both lack oral bioavailability and are susceptible to proteolytic cleavage and renal excretion. Here, APLN is linked to pulmonary arterial hypertension.