Abstract 17581: Evidence for Circulating Stem Cells Derived from the Human Heart and Their Therapeutic Potential

Introduction and Hypothesis: Many studies have shown resident cardiac stem cells in myocardium as well as epicardial progenitor cells in epicardium. However, the presence of stem cells in the endocardium has not been elucidated. In this study, we identified circulating multipotent stem cells from human peripheral blood. Furthermore, we investigated the origin and the therapeutic potential of these cells. Methods and Results: We identified a new population of cells from human peripheral blood mononuclear cells, which were quite different from previously reported stem cells. Newly identified cells expressed genes such as Oct3/4, KLF4, Nanog, and c-Myc. Moreover, FACS analysis precluded the possibility that these cells might be hematopoietic stem cells. To investigate the origin of these cells, we collected peripheral blood from patients undergoing bone marrow, liver, heart, or kidney transplantation. After culturing these cells, we could confirm that these stem cells were derived from the human heart by identifying the HLA types or the STR (short tandem repeat) profiles. In addition, we demonstrated that Nuclear Factor of Activated T-cells (NFAT)-positive and CD31-positive circulating cells in peripheral blood were derived from NFAT-positive cells in the endocardium. These cells had multipotency, indicating the ability of differentiation not only into mesodermal lineages, but also into ectodermal or endodermal lineages. When injected into the mouse heart in vivo , these stem cells were differentiated into multiple lineages, resulting in the improvement of the heart function. We established more than 200 cell lines from peripheral blood of patients with coronary artery diseases, cardiomyopathies, hematologic diseases, liver diseases, and kidney diseases. Conclusions: We demonstrated the existence of novel circulating multipotent stem cells in human peripheral blood, which express NFAT. Interestingly, these cells are derived from the tissue-resident stem cells of the endocardium of the human heart. Our findings suggest that these stem cells obtainable from peripheral blood could be a promising tool for heart regeneration.