Fig. 6

Elderly MSCs with a “youthful” phenotype can be expanded on young ECM for cell-based therapies. a Ratio of young to elderly MSCs changes with chronological age. In the elderly, the proportion of young (“youthful”) MSCs has dropped to approximately 8–10% of the total population. This can be clearly seen in the brightfield micrographs. In the young, virtually all cells display a fibroblastic spindle-shaped morphology. With advancing age, cells become larger and spread across the surface (black arrows), but fibroblastic cells can still be found (white arrows). b Our current studies strongly suggest it is possible to rescue these “youthful” cells by separation from the parent MSC population, based on cell size and SSEA-4 expression, and then expand them on a young ECM to bank large quantities of high-quality autologous MSCs for more effective treatment of age-related diseases. ECM extracellular matrix, FSC forward scatter, MSC mesenchymal stem cell, SSEA-4 stage-specific embryonic antigen-4