Characterization of age-dependent differences in adipose stem cells (ASCs) and bone marrow stem cells (BMSCs). (a) Representative photomicrographs of MSCs show undifferentiated control cells (left), lipid inclusions with Oil Red O (middle), and mineralization with Alizarin Red (right) in ASCs from young (top) and old (bottom) donors. Original magnification of undifferentiated and mineralized cultures was ×10, and lipid inclusions were at ×40. (b) Quantification of differentiation potentials of ASCs from young and old donors shown as OD normalized to protein for cells cultured in osteoblastogenic and adipocytogenic conditions. Bars represent mean ± SEM and are representative of three quantifications. *P < 0.05. (c) A representative plot from flow cytometry shows forward versus side light scatter used to assess cell size and heterogeneity of MSCs. Green plots demonstrate ASCs, and red plots indicate BMSCs. Data for young donors are on the right, and for old donors, on the left.