Identification of Circulating Stem Cells Originating From the Endocardium of the Human Heart

Background: There have been several studies showing the presence of cardiac stem cells in myocardium and epicardial progenitor cells in epicardium, respectively. Until recently, however, there has been no report showing the presence of stem cells in the endocardium. In this study, we identified circulating multipotent stem cells from human peripheral blood. Furthermore, we investigated the origin of these cells and the differentiation potential in vivo. Methods and Results: From human peripheral blood mononuclear cells grown on non-coated dishes, we identified a new population of cells, which were quite distinct from previously reported other stem cells. Newly identified cells had the gene profiles such as Oct3/4, KLF4, Nanog, and c-Myc. Moreover, FACS analysis excluded the possibility that these cells might be hematopoietic stem cells. To investigate the origin of these cells, we collected peripheral blood from patients receiving the transplantation of bone marrow, liver, heart, or kidney. After culturin...