Abstract 10128: Recombinant Human Placental Growth Factor-2 Treatment in Porcine Ischemic Cardiomyopathy

Abstract

Background: Placental growth factor (PlGF)-2 induces neovascularization and improves myocardial function in atherosclerotic rodent myocardial ischemia models without stimulating plaque angiogenesis. This promising therapeutic profile of PlGF-2 warrants a double blind, randomized, and placebo-controlled feasibility and efficacy study in a large animal model, representative of human disease. Methods: We induced myocardial infarction (MI) in domestic pigs using a 75 min balloon occlusion of the mid-LAD followed by reperfusion. After 4 w, we randomized pigs with marked LV dysfunction (LVEF<40%) to continuous IV infusion of 5, 15, 45 μg/kg/day rhPlGF-2 or PBS (CON) for 2 w using osmotic pumps. We evaluated treatment effect 8 w after MI using comprehensive MRI analysis of LV function and structure and performed postmortem histological analyses of LV vascularization and fibrotic remodeling. Results: In the pilot study (3 pigs/dose), PIGF plasma concentrations showed stable and sustained dose-dependent increases for 28 days without organ-specific side effects or systemic toxicity. Myocardial Ischemia/reperfusion induced LV dysfunction at 4 w (infarct size, 16±4 % of LV mass, n=42; LVEF, 34±4 %, range 19%-40%). In the dose escalation study using 5 (n=10), 15 or 45 μg/kg/day PlGF (n=11 per group), global LV function, and regional myocardial blood flow at rest or during stress, and infarct size did not differ between CON (n=10) and PlGF (Figure 1). Capillary densities and extent of LV interstitial fibrosis in infarct core and border zone were comparable between CON and PlGF. Conclusions: In this blinded randomized controlled trial, rhPIGF-2 did not improve global cardiac function in a porcine model of chronic ischemic cardiomyopathy, and failed to recapitulate therapeutic neovascularization reported in rodents. Our data emphasize the critical need for robust double blind, placebo controlled trials in representative large animal models before clinical translation.