Original Research: Adipose-derived stem cells from younger donors, but not aging donors, inspire the host self-healing capability through its secreta.

Adipose-derived stem cells demonstrate promising effects in promoting cutaneous wound healing, but the mechanisms are still not well defined and contradictory views are still debatable. In the present research, we established a mouse cutaneous wound model and investigated the effects of adipose-derived stem cells in wound healing. Adipocyte, adipose-derived stem cells, and epidermal keratinocyte stem cells were isolated from younger and aged donors according to the standard protocol. The conditioned medium either from adipose-derived stem cells or from adipocytes was used to treat epidermal keratinocyte cells. The results showed that adipocytes or adipose-derived stem cells isolated from younger donors demonstrated mild advantage over those cells isolated from aging donors. Adipose-derived stem cells showed stronger stimuli than adipocytes, and the adipose-derived stem cells or adipocytes from younger donors enabled to support higher growth rate of keratinocyte stem cells. The invasion of vasculature was observed at day 10 after posttransplantation in the mice bearing the keratinocyte stem cells or combination of keratinocyte stem cells with adipose-derived stem cells; however, simply inoculating keratinocyte stem cells from aging donors did not result in vasculature formation. Adipose-derived stem cells isolated from younger donors were able to inspire the host's self-healing capabilities, and age-associated factors should be taken into consideration when designing a feasible therapeutic treatment for skin regeneration.