Introduction:

Wound healing is a complex cascade involving the orchestration of inflammatory cells, skin fibroblasts, keratinocytes, and endothelial cells. These cells achieve tissue repair through an interchange of cytokines and growth factors through a controlled inflammation, angiogenesis, and remodeling process. Disruptions in the wound-healing process by comorbid conditions lead to significant morbidity and mortality. Stem cell therapy has emerged as a new strategy to facilitate the wound healing process. Stem cells harvested from different sources can be used for wound repair and regeneration (endothelial progenitor cells, bone marrow, adipose tissue, dermal and inducible pluripotent stem cells). We aimed to review clinical, translational, and primary literature on stem cell therapies in chronic wounds and summarize practical clinical applications to dermatological care.

Materials and Methods:

A comprehensive search of Pubmed, Embase, Web of Science, Google Scholar, and Cochrane Library was conducted for studies relating to stem cells and wound healing. Duplicate results were removed using Covidence. Titles and abstracts were screened by two independent researchers (BF and KR), with discrepancies resolved through discussion and mutual agreement. Articles were excluded if they were review-type or commentary-type articles.

Results:

A total of 22,454 articles were retrieved from the search. Deduplication removed 905, and automation removed an additional 18,363 articles. After an initial screening of titles and abstracts, 170 articles remained. Full-text screening resulted in an additional 126 articles being removed, leaving 44 included studies.

Discussion:

Stem cells used for wound repair and regeneration include endothelial progenitor stem cells and adult stem cells, in the forms of bone marrow-derived mesenchymal stem cells, adipose tissue stem cells, and inducible pluripotent stem cells. Among these sources, adipose tissue-derived mesenchymal stem cells (AD-MSCs) are ideally used due to the abundant supply of fat tissue, ease of isolation, extensive proliferative capacities ex vivo, and their ability to secrete pro-angiogenic factors. AD-MSCs have been used to enhance wound healing in peripheral arterial disease, diabetic wounds, hypertensive ulcers, bullous diabeticorum, venous ulcers, and postsurgical wounds after Mohs micrographic surgery. These cells have been delivered to the tissue topically, with scaffolds, combined with plasma-rich proteins, and through atelocollagen in various human studies. These approaches, when combined with local wound care practices, resulted in decreased pain, shorter wound healing times, and better cosmesis.

Conclusions:

Stem cell transplantation is a potential therapeutic approach in the wound healing process. Transplanted stem cells do not only differentiate into multiple skin cell types but also provide cytokine and growth factors required for wound healing resulting in increased angiogenesis. Thus, this approach may be regarded as an attractive option for intractable wounds that cause major clinical problems, especially chronic lower leg wounds. It can also be used after Mohs micrographic surgery for defects left to heal by secondary intention. Stem cell application may reduce the overall cost burden on the healthcare system and improve the quality of life for patients.