FIG. 1.

Multipotential differentiation of primary human bone marrow stromal cells (hBMSCs) (first row) and D1 stem cells (second row). Cells were cultured in adipogenic (A), chondrogenic (B), and osteogenic (C) conditions to assess the capability of these multipotential cells to exhibit markers typical of adipocytes, chondrocytes, and osteoblasts, respectively. For adipogenic conditions, cells were cultured for 21 days and stained with Oil Red O for lipid vacuoles (red). hBMSCs were counterstained with hematoxylin (blue), whereas D1 cells (A, 2nd row) were not. For chondrogenic conditions, cell pellets were cultured for 14 days in medium supplemented with 10 ng/mL transforming growth factor beta-1. Cell pellets were fixed, sectioned, and stained with Safranin-O for detection of glycosaminoglycans. To assess osteogenic differentiation, cells were cultured in complete medium supplemented with 50 μg/mL ascorbic acid and 10 mM β-glycerophosphate and with (hBMSC) or without (D1 cells) 0.1 μM dexamethasone and subjected to von Kossa staining to highlight mineral formation (day 21).