Figure 1: Left and middle panels: Flow cytometric analysis of the cellular outgrowth from a human atrial appendage explant in the primary tissue culture, showing MSC (CD13+, CD73+, and CD105+) but not hematopoietic (CD45) marker expression. Upper right panel: Photomicrograph of a human atrial explant with cellular outgrowth; middle right panel: human CSs; lower right panel: human CDCs.