Abstract Body (Do not enter title and authors here): Introduction: Urocortin-2 (UCN-2), a peptide which is part of the corticotropin-releasing factor (CRF) family, functions as an autocrine and paracrine factor, exerting its effects on cardiac and pulmonary function through agonism of CRF2 receptors. Although acute administration of UCN-2 has shown promise by improving heart and lung function in conditions like heart failure (HF) and pulmonary hypertension (PH), its limited stability impedes its chronic therapeutic use.
Hypothesis: In this study, we explored the efficacy of COR-1389, a potent, selective and long-acting CRF2 agonist peptide, in the Sugen 5416 (VEGFR2 inhibitor, Su) combined with hypoxia (Hx) rat model of PH and right heart failure (RHF).
Methods: To this aim, male adult Sprague Dawley rats were divided into three groups: Control rats (normoxia) were compared with rats injected subcutaneously with 20 mg/kg Sugen 5416 and exposed to chronic hypoxia for 3 weeks, followed by 2 weeks of normoxia. At 5 weeks, control rats and one SuHx group received subcutaneously vehicle (control and SuHx), while the third group received COR-1389 at a dose of 100 μg/kg every 4 days subcutaneously for 3 weeks (SuHx + COR-1389). At 8 weeks, cardiac and pulmonary hemodynamic functions of the three groups were evaluated using echocardiography and right heart catheterization, and heart and lung tissue were evaluated by histology and immunohistochemistry.
Results: Compared to controls (n=10), SuHx exhibited increased mean pulmonary arterial pressure (mPAP), right ventricle (RV) hypertrophy (Fulton Index/body weight), muscularization of distal pulmonary arteries, RV fibrosis and cardiomyocyte hypertrophy, alongside reduced RV systolic function (Tricuspid Annular Plane Systolic Excursion, TAPSE) and cardiac output (CO). Conversely, compared to the SuHx + vehicle group (n=11), curative treatment with COR-1389 for 3 weeks in SuHx rats (n=13) led to enhanced RV systolic function (TAPSE) and CO, together with reductions in mPAP, RV hypertrophy, muscularization of pulmonary arteries, RV fibrosis and cardiomyocyte hypertrophy. Systolic blood pressure remained unchanged across all groups.
Conclusion: These findings indicate that COR-1389 ameliorates the deteriorating cardiopulmonary parameters observed in the SuHx model and represents a promising approach for the treatment of PH and RHF.