Abstract 192: Histological and Functional Assessment of Human Placental Stem Cells in an Induced Myocardial Infarction in Rats

Abstract

Purpose: Human bone marrow mesenchymal stem cells (hbmMSCs) have been studied extensively for myocardial regenerative therapy. However, such cells require invasive procreation and suffer from donor age-related declining quality. Recently, a more abundant resource of young MSCs has been isolated from an otherwise discarded organ: the human placenta mesenchymal stem cells (hpMSCs). In this study, we wanted to examine the survival, differentiation, and functionality of xenogeneic hpMSCs when implanted into an induced myocardial rat infarction. Methods: To inspect their stemness,hpMSCs underwent an In Vitro cardiac cell differentiation in a DMEM medium containing 5 Azacytidine. Additionally, hpMSCs were tested in a myocardial infarction animal model. Female Lewis rats (40 animals) underwent left coronary artery ligation. Animals were divided into 4 groups. Group 1 was injected with hpMSCs in the peri-infarct region. Groups 2 and 3 received hbmMSCs and In Vitro differentiated hbmMSCs into cardiomyocytes respectively. Cell free medium was injected in group 4. Echocardiography was performed at baseline, day 4, weeks 3, 6, and 9 after ligation. Myocardial tissues were harvested and studied immunohistochemically for specific muscular and cardiac markers (Actin and Troponin I) on weeks 6 and 10. Results: In Vitro differentiation into cardiomyocyte lineage was achieved with the hpMSCs. HpMSCs were detected within rat myocardium by week 6 after their implantation. These cells stained positively for Actin and Troponin I. Preliminary echocardiographic data show cardiac functional increase in group 1. Whether hpMSCs can provide a superior effect than hbmMSCs or differentiated hbmMSCs is being investigated. Conclusions: In Vitro studies indicated that the hpMSCs can be differentiated into cardiac cells. When implanted into the rat infarcted myocardium, hpMSCs survived and were able to differentiate into cardiomyocytes. These cells appeared to increase cardiac function in an induced myocardial infarction rat model. With the advantages of easy availability and young age, hpMSCs could be more suitable for myocardial regenerative therapy.