Fig. 6

A subpopulation of BM-MSCs, expressing CD133, was associated with the formation of aggregates. A CD133, CD90, and CD105 expression was determined by flow cytometry in the original BM-MSCs (P1) (original), untreated BM-MSCs (untreated), and SMG-ECM-treated aggregates (Agg/SMG-ECM) or monolayer cells (Mono/SMG-ECM). Data are the mean ± SD from a representative experiment. The experiment was repeated 4 times, and in each experiment, 4 replicates (each using cells from a different donor) were used. *p < 0.05, versus all the other treatment groups for a specific marker. B Comparison of the aggregates formed by the CD133+ versus CD133− BM-MSC subpopulations after 14 days in culture. Bar: 200 µm. C Morphological comparison of the aggregates formed by the CD133  versus CD133− BM-MSC subpopulations. Arrow indicates PAS-positive cells, Bar: 50 µm; TEM shows differences in ultrastructure of the aggregates formed by the two BM-MSC subpopulations. (N: cell nucleus; SG: secretory granule), note: scale bar distances are shown in each panel