Apelin analog treatment reverses severe pulmonary arterial hypertension and right ventricular heart failure.

Pulmonary arterial hypertension (PAH) is a progressive vascular syndrome characterized by aberrant signaling, severe pulmonary artery remodeling, and right ventricular (RV) failure, a major driver of morbidity and mortality. Dysregulation of the apelinergic pathway has been implicated in pulmonary vascular remodeling in PAH. Using a sugen-hypoxia rat model of PAH, we assessed the ability of a potentially novel apelin analog, resistant to native peptidase degradation, to reverse the pathological hallmarks of PAH and RV dysfunction. Apelin analog therapy corrected the vascular lesions in the lungs and nearly normalized pulmonary arterial pressures. Early cardiorenal syndrome, RV dilation, and dysfunction, as well as RV cardiomyocyte and fibroblast activation induced by pressure overload, were also reversed by apelin analog treatment. Single-nucleus RNA-seq of the lungs and RV revealed apelin-analog treatment activated several protective pathways, including rebalancing protective bone morphogenetic protein receptor type 2 (BMPR2) signaling to counteract excessive pathogenic TGF-β receptor 2 (TGFBR2) activity in PAH. These findings highlight the therapeutic potential of exogenous apelin in reversing pulmonary vascular and cardiac pathologies in PAH and support further investigation to evaluate the clinical benefits of apelin analog treatment in patients with PAH and RV failure.