Evaluation of xenogeneic extracellular matrix fabricated from CuCl ₂ -conditioned mesenchymal stem cell sheets as a bioactive wound dressing material

The extracellular matrix has drawn considerable interest in tissue engineering not only acts as a bioactive three-dimensional scaffold but also regulates cell behaviors through providing biochemical signals. Extracellular matrix-based biomaterials, mainly derived from xenogeneic tissues, have shown positive outcomes in promoting cutaneous wound healing. However, such extracellular matrices only contain low doses of growth factors, which limit their therapeutic efficiency. Recent reports demonstrated that cell sheets made from mesenchymal stem cell can accelerate wound repair through enhanced re-epithelialization and angiogenesis, but its clinical translation is hindered by several limitations, such as the risk of aberrant immune responses and cost implications. In this study, acellular extracellular matrices were prepared from CuCl ₂ -conditioned mesenchymal stem cell sheets and their in vivo wound healing properties were evaluated in a mouse model of full-thickness skin defect. We found that extracellular matrices derived from CuCl ₂ -conditioned mesenchymal stem cell sheets have a compact surface with thick solid-like cross-sectional structure. Moreover, CuCl ₂ dramatically enriched the extracellular matrices with collagen I, collagen III, transforming growth factor-β1, vascular endothelial growth factor, and basic fibroblast growth factor via hypoxia-inducible factor-1α activation. And as a consequence, the resulting extracellular matrices showed markedly improved in vivo wound healing potency through early adipocyte mobilization, enhanced granulation tissues formation, rapid re-epithelialization, and augmented angiogenesis. Therefore, we consider that the extracellular matrix derived from CuCl ₂ -conditioned mesenchymal stem cell sheets has the potential for clinical translation and may lead to a novel strategy for wound management.