Exosome Derived from Mesenchymal Stem Cells Alleviates Pathological Scars by Inhibiting the Proliferation, Migration and Protein Expression of Fibroblasts via Delivering miR-138-5p to Target SIRT1.

Introduction: The therapies of using exosomes derived from mesenchymal stem cells (MSC-Exo) for wound healing and scar attenuation and micro RNAs (miRNAs) for regulation of genes by translational inhibition and mRNA destabilization obtained great achievements. Silent information regulator 1 (SIRT1) is the silent information, which has an intricate role in many biological processes. However, the effects of SIRT1 and miR-138-5p loaded in MSC-Exo on pathological scars remain unclear. Methods: MSC-Exo was isolated and identified by ultracentrifugation, transmission electron microscopy, nanoparticle size measuring instrument and Western blot assays. The relationship between SIRT1 and miR-138-5p was verified by a double-luciferase reporter assay. Cell Counting Kit-8, Τranswell, scratch, and Western blot assays were used to evaluate the proliferation and migration of human skin fibroblasts (HSFs), and the protein expression of SIRT1, NF-κB, α-SMA and TGF-ß1 in HSFs, respectively. Flow cytometry was used to assess the apoptosis and cell cycle of HSFs affected by SIRT1. Results: Our study demonstrated that miR-138-5p loaded in MSC-Exo could attenuate proliferation, migration and protein expression of HSFs-derived NF-κB, α-SMA, and TGF-ß1 by targeting to SIRT1 gene, which confirmed the potential effects of MSC-Exo in alleviating pathological scars by performing as a miRNA's delivery vehicle. Conclusion: Exosomes derived from MSCs acting as a delivery vehicle to deliver miR-138-5p can downregulate SIRT1 to inhibit the growth and protein expression of HSFs and attenuate pathological scars.

Cd271 mediates proliferation and differentiation of epidermal stem cells to support cutaneous burn wound healing.

Burn wounds can significantly reduce the quality of life of patients with respect to their physiology and psychology and can even threaten their lives. Many treatments have been proposed, including stem cell therapy but no effective method can as yet cure such damage. Our study highlights the role of Cd271 in epidermal stem cells (eSC) during the healing of burn wounds. The expression of Cd271 increases together with burn wound healing. Injection of Cd271-over-expressing eSC into wounds promotes the healing rate in a mouse burn model. Over-expression of Cd271 enhances the abilities of eSC with regard to their differentiation, proliferation and migration and even their resistance to apoptosis in vitro. These results are in accordance with a hypothesis suggesting that Cd271 promotes the healing of skin burn wounds by improving the potential of eSC for differentiation, proliferation and migration. Our findings shed light on the role of Cd271 in wound healing and may provide new therapeutic approaches for curing burn wounds of the skin.

[Clinical observation on the paraumbilical skin flaps application in the repair of the wounds of 39 patients with severe burns].

OBJECTIVE: To evaluate the effectiveness of paraumbilical skin flaps for the repair of the severe burn wounds. METHODS: Pedicled, island, or free paraumbilical skin flaps, as well as combined transplantation of several kinds of flaps were used to repair the wounds of 39 patients with severe burns. The largest paraumbilical skin flap was 55 x 27 cm(2) in area, with the end approaching the armpit midline of the axilla on the same side, and extending 10cm from the abdominal midline. The survival, color, elasticity of the flaps, degree of deformity resulted from scar contracture, and the condition of donor area were observed. RESULTS: All the paraumbilical skin flaps survived, without obvious infection subsequent to complete debridement of the wounds. The flaps exhibited good color and elasticity, without scar contracture after 1 to 46 months in 33 patients. No obvious scar formation was observed in the donor area. CONCLUSION: Paraumbilical skin flap is an ideal one for the early repair of deep burn wounds, because it can cover a large area, and can be transferred in different ways according to the area and the position of the wounds.