Wound Contraction Is Significantly Reduced by the Use of Microcarriers to Deliver Keratinocytes and Fibroblasts in an In Vivo Pig Model of Wound Repair and Regeneration

In full-thickness injuries caused by extensive burns or penetrating traumatic injuries, the natural epidermal stem cell niche is destroyed, and wound healing occurs through migration of cells from the wound edges and wound contraction. This can lead to significant contracture formation, especially in large full-thickness injuries, causing lack of mobility and pain. Contraction is reduced when wounds are treated using split-thickness skin grafts (STSG) or dermal substitutes, particularly in combination with cultured autologous keratinocytes, delivered as confluent sheets or sprayed as a single cell suspension (SAK). Here, we show that the application of keratinocytes alone or keratinocytes with fibroblasts, delivered on microcarriers, in combination with STSG or a dermal substitute, significantly reduces contraction of wounds in vivo in a porcine model of wound repair and regeneration. A decrease in alpha-smooth muscle actin–positive myofibroblasts, the cell type responsible for wound contraction, accompanies the reduction in contraction. These findings demonstrate the potential for a significant clinical advantage in the treatment of full-thickness injuries.