Keratinocyte-Like Cells Trans-Differentiated from Human Adipose-Derived Stem Cells, Facilitate Skin Wound Healing in Mice

BACKGROUND: Mesenchymal stem cells (MSCs) have been reported to promote wound healing in both animal models and human studies. Among MSCs, adipose-derived stem cells (ADSCs) can be easily harvested in large quantities. OBJECTIVE: We investigated whether skin wound healing in mice can be facilitated by keratinocyte-like cells differentiated from ADSCs (KC-ADSCs). METHODS: For the wound contraction and epithelialization model, a 20 mm×20 mm fullthickness skin wound was made on the dorsum. For the wound epithelialization model, a 6 mm×6 mm full-thickness skin wound was made on the dorsum. A nitrile rubber stent with an inner diameter of 8 mm was sutured around the wounds to minimize wound contraction. Undifferentiated ADSCs (uADSCs) or KC-ADSCs was injected around the wound base in both models. To evaluate whether the injected ADSCs could enhance wound contraction in a skin wound, the contractile activity of ADSCs was assessed by an in vitro type I collagen gel contraction assay. Alpha-smooth muscle actin (αSMA) expressions in uADSCs and KC-ADSCs were also evaluated by flow cytometry and real-time polymerase chain reaction. RESULTS: In a wound contraction and epithelialization model, KC-ADSCs further facilitated wound healing compared with uADSCs. In a wound epithelialization model, KC-ADSCs also further facilitated wound epithelialization compared with uADSCs. The contractile activity of KC-ADSCs was lower than that of uADSCs. The uADSCs expressed high levels of αSMA, which decreased after the differentiation into keratinocyte-like cells. CONCLUSION: Our results suggest that the wound healing effect of KC-ADSCs depends primarily on re-epithelialization rather than wound contraction.