1 2 3 4 5 6 7 8 9 101112131415161718192021 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 Title Electrophysiological study to evaluate the integration of adult cardiac progenitor cells in the host tissue. -In vitro model of cell transplantation- Summary Background: Congestive heart failure and coronary artery disease are the leading cause of morbidity and mortality in industrial societies, despite recent advances in medical and device therapies. Limited strategies are available to address and oppose the central pathophysiologic process underlying the development of heart failure, which is the loss of cardiomyocytes, permanently compromising myocardial contractile function. Cell-based therapies are a promising alternative, given the basic assumption that left ventricular dysfunction is largely due to the loss of a critical number of cardiomyocytes and that it could be partly reversed by implantation of new contractile cells into the post-infarction scar. Different stem cell types as possible sources for cell therapy, including embryonic stem cells (ESCs), skeletal myoblasts (SkMCs), adult bone marrow (BM) derived cells and mesenchymal stem cells (MSCs) have been studied. The first clinical applications of autologus cells indicated the difficulties associated with non-cardiac adult stem (MSC/SkMCs) to cross their lineage boundaries and transdifferentiate into cardiomyocytes. When transplanted in the injured heart they were not able to establish a correct electrical coupling between grafted cells and host parenchyma which resulted in a high incidence of ventricular arrhythmias. We have successfully isolated cardiac progenitor cells (CPCs) from murine heart and from small biopsies of human myocardium and expanded them ex vivo through several generations without losing differentiation potential into cardiomyocytes and vascular cells. These cells are spontaneously shed from human surgical specimens and animal (mouse, rat, guinea pig, pig) heart samples in primary culture. This heterogeneous population of cells forms multi-cellular clusters, dubbed Cardiospheres (CSs). Aim: The purpose of this study is to explore the mechanical and physiological reconstitution as well as the elettrical interaction between grafted cells and host cardiomyocytes using an in-vitro model of adult cardiac progenitor cells transplantation. Study will be performed in normoxic condition and after simulation of severe ischemic injury. Method: We will combine our acquired technique for CPC isolation and characterization, with the in vitro heart slide culture to map the capability of CSs-derived cells to electrical interact with the host cardiac tissue. To perform the study of excitable heart–integrated CPCs we will use the Microelectrode Arrays system (MEAs). MEAs system allows the continuously monitoring of spatial and temporal structure and dynamics of electrical activity in the developing cardiac structure. These heart slice model will be then used as an in vitro model to study mechanical integration and to measure forces of contraction that can be attributed to transplanted CPCs. Moreover we will characterize the contractile and integrative properties of CPCs-derived cardiomyocytes in condition of ischemically damaged myocardium.