Figure 1.

Model for stem cell-based therapy for wound healing in epithelium lined organs. The cellular component of the wound bed consists primarily of fibroblasts, endothelial cells, and macrophages. The epithelial response consists of stem cells that produce less-differentiated cells that are temporarily associated with the wound bed. Immediately after injury, there is a surge in the inflammatory response at the wound site to eliminate microbes and activate the healing process. The timing and balance between wound repair and elimination of microbes in the wound bed must be orchestrated. MSCs are uniquely poised in the wound to communicate with the overlying epithelial cells and the inflammatory cells within wound bed to orchestrate their coordinated efforts toward wound healing. Stem cells applied to wounds can contribute to healing by: (1) directly differentiating into daughter cells that form building blocks for tissue renewal (such as keratinocytes, fibroblasts, and pericytes); (2) immune-modulation; (3) secretion of growth factors that mediate wound healing by paracrine signaling; and (4) mobilization of resident stem cell niche to participate in wound healing response. MSCs=mesenchymal stem cells. Color image available online at www.liebertpub.com/wound