Mesenchymal Stem Cell Therapies for Skin Repair and Regeneration

Abstract

In the clinic, partial to full-thickness skin defects are generally treated through debridement and patching with autologous skin grafts. Autologous skin grafts are in severely limited supply, especially for ill patients lacking healthy tissue to donate to themselves. Stem cells have come into interest as a novel, viable way to heal skin wounds. Mesenchymal stem cells (MSCs) are of particular interest due to its common mesoderm germ layer origins as skin tissue. Mesenchymal stem cells are primarily derived from bone marrow, adipose tissue and umbilical cord. Bone marrow MSCs have been widely applied to chronic wounds in non-diabetic and diabetic subjects with positive results for wound healing and closure. Adipose-derived stem cells (ASCs) are a more recent application to skin healing. It has been found that ASCs secrete growth factors positive for augmenting wound healing, such as TGF-β. ASCs are also a more attractive cell source for clinical use due their great abundance and ease of procurement from discarded tissues from cosmetic surgery procedures. Most recently, umbilical cord MSCs have been tested for its effects on wound healing, showing that the cells' paracrine effects can accelerate skin wound healing. Overall, mesenchymal stem cells show great promise to progress skin wound treatments, especially for chronic wounds. However, more clinical research is needed prior to patient application. Mesenchymal Stem Cell Therapies for Skin Repair and Regeneration 2/3Copyright: ©2017 Lam in group 1 and 76% of patients in group 2 did not need further wound care. In contrast, 80% of patients in the saline control group required surgical intervention. In a 16 month follow-up with group 2, the wound was completely healed with no signs of contracture.Chronic wounds are a notorious complication for diabetic patients. Bone marrow MSCs have been explored as a treatment option [15][16][17]. In one study, allogeneic MSCs were compared to the MSCs' acellular derivatives in a non-obese diabetic (NOD) mouse model [15]. The cells or acellular derivatives were intradermally injected around the wound site. Mice treated with the acellular derivative displayed significantly higher percentages of wound closure on days 4, 6, and 8 compared to wounds that received cells or control vehicles. Acellular products produced less pronounced inflammatory response, more granulation tissue, and a higher density of collagen fibers. This study suggests that growth factors present in bone marrow MSCs require time for cell release, whereas during the decellularization process these growth factors are released and readily available to stimulate the wound healing process. Adipose-derived MSCsWhile bone marrow MSCs can be difficult to obtain, adiposederived stem cells (ASCs) are much more abundant and are easily isolated from subcutaneous fat tissue and lipoaspirates. In addition, these adipose tissues are generally discarded from plastic surgery clinics, making excellent use of otherwise disposed tissue. ASCs have been widely explored for sk...