Abstract 18122: Reduction of Scar Tissue after GHRH-Agonist Treatment in a Swine Model of Sub-acute Ischemic Cardiomyopathy

Introduction: Growth hormone-releasing hormone receptor agonists (GHRH-A) stimulate cardiac repair following myocardial infarction (MI) in rats through the activation of the GHRH signaling pathway within the heart. Hypothesis: We tested the hypothesis that the administration of GHRH-A prevents ventricular remodeling in a swine sub-acute MI model. Methods: Twelve female Yorkshire swine (25-30 Kg) underwent transient occlusion of the LAD coronary artery (MI). Two-weeks post-MI, swine were randomized to receive injections of either 30 μg/Kg GHRH-A (MR-409) (GHRH-A group; n=6) or vehicle (placebo group; n=6). Cardiac MRI, pressure volume loops and measures of endothelial function were obtained at multiple time points. Infarct-, border- and remote- (non-infarcted) zones were assessed for growth hormone-releasing hormone receptor (GHRHR) by immunohistochemistry. Results: Four-weeks of GHRH-A treatment resulted in reduced scar mass (GHRH-A: –21.9±6.42%; p=0.02; placebo: 10.9±5.88%; p=0.25; Two-way ANOVA; p=0.003...