Fig. 1

MSC cultures were separated based on their cell fitness in vitro into weak and vigorous cell cultures. a Colonies were stained with Giemsa (colony-forming unit assay (CFU)) and b counted at the beginning of in vitro cultures, while c MSC cumulative population doublings (CPD) were calculated at the end of cell cultures (n = 3; values represent the mean ± SEM). *p < 0.05. Expression of the MSC-positive markers CD44 (orange line), CD90 (dark green line), and CD105 (light green line), and the negative marker CD14 (blue line) was tested by flow cytometry analysis (d), as shown by a representative sample (grey line = unstained control). MNC mononuclear cells