Studies in animal models of PAH have demonstrated that infusion of apelin receptor agonist peptides is beneficial in attenuating features of PAH, reducing vascular muscularization, right ventricular systolic pressure (RVSP), and hypertrophy (Falcao-Pires et al., 2009; Alastalo et al., 2011; Yang et al., 2017; 2019). Here, APLNR is linked to pulmonary arterial hypertension.