Abstract 10495: Mechanism of Cardiac Repair in Rat Myocardial Infarction Model Treated with Extracellular Vesicles from Differentiating Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Abstract

Introduction: A few reports showed the therapeutic effects of extracellular vesicles (EVs) secreted from induced pluripotent stem cell-derived cardiomyocytes (iPSCM) on animal ischemic cardiomyopathy models. However, the mechanism of the cardiac function restoration after EVs administration remained unclear. Then, this study aimed to identify the mechanism for the restoration of cardiac function after iPSCM-EVs treatment. Methods: We collected EVs from differentiating iPSCM (TnT positive > 80%) culture medium. Comprehensive miRNA-seq and proteome analysis in the EVs were performed. In vitro myocardial contraction assay and wound healing assay, and ex vivo aortic ring assay were performed. In vivo , we designed a rat model of myocardial infarction by left anterior descending artery (LAD) ligation and divided rats into two groups. Two weeks after LAD ligation, iPSCM-EVs (Group EV) or PBS (Group Ctl) were injected peri-infarct zone. We analyzed the sequential cardiac function, histological analysis, and comprehensive RNA sequence analysis of the border zone before the treatment and 3, 7, 14, and 28 days after the treatment (n=5 at each time point in each group). Results: EVs showed the potential of increased myocyte contraction velocity (11±0.7 vs 6.6±0.6 μm/s, mean±SD, p < 0.01) and enhanced endothelial migration in vitro and facilitated angiogenesis (46±6 vs 13±5 sprouting count, p=0.02) ex vivo . In vivo , Group EVs showed higher LVEF (57±5 vs 38±4 % at day28, p < 0.01) and smaller LVDd (6.8±0.3 vs 8.5±0.8 mm at day28, p < 0.01). Histological analysis showed a lower % fibrosis area in Group EV (22±6 vs 12±5 % at day28, p < 0.01) and significantly higher microvascular (vWF positive: 1.7 at day14 and 2.1 times higher at day28) and arterial (vWF and αSMA positive: 4.3 at day14 and 6.2 times higher at day28) density. RNA expression analysis showed the expression of HGF, SDF-1, and IGF-1 increased in Group EVs on day3 and 7. CTGF and collagen 1 increased in Group Ctl on day14 and 28. Conclusions: Intracardiac injection of iPSCM-EVs improved cardiac function in rat MI model via angiogenesis, increased myocyte contraction, and reduced fibrosis. Comprehensive expression analysis suggested the mechanism of action of EVs in cardiac repair.