Doubling time assay of hASC-M, hASC-T, hASC-TS and hASC-TE cells. A total of 13.0 x 106 cells/cm2 were plated at T0 and detached at the indicated time points. Three different values were obtained for each cell line. Cells were evaluated at the following cell culture passages: hASCs-M P7; hASCs-T P17; hASCs-TS and hASCs-TE P21. The histogram represents the mean value ± SD of four different experiments.