Stem cell therapy on skin: Mechanisms, recent advances and drug reviewing issues

Abstract

Stem cell products and its clinical applications have been widely discussed in recent years, particularly when the Japanese "induced pluripotent stem cells" founder Dr. Yamanaka was awarded as Nobel Prize laureate in 2013. For decades, major progresses have been achieved in the stem cell biology field, and more and more evidence showed that skin stem cells are involved in the process of skin repair. Stem/progenitor cells of the epidermis are recognized to play the most essential role in the tissue regeneration of skin. In this review, we first illustrated basic stem cell characteristics and various stem cell subtypes resided in the skin. Second, we provided several literatures to elucidate how stem/progenitor cells collaborate in the process of skin repair with the evidence from animal model studies and in vitro experiments. Third, we also introduced several examples of skin cell products on the pharmaceutic market and the ongoing clinical trials aiming for unmet medical difficulties of skin. Last but not least, we summarized general reviewing concerns and some disputatious issues on dermatological cell products. With this concise review, we hope to provide further beneficial suggestions for the development of more effective and safer dermatological stem/progenitor cell products in the future.

The Future of Regenerative Medicine: Cell Therapy Using Pluripotent Stem Cells and Acellular Therapies Based on Extracellular Vesicles

“…Skin wounds, principally caused by traumas or thermal burns, can be self-repaired by the body [5,54]. The different stages of self-wound healing include: (1) hemostasis to stop blood loss and provide a scaffold for cell migration, (2) inflammation to eliminate pathogens and tissue debris, (3) proliferation in particular of keratinocytes to achieve wound coverage and (4) remodeling of collagens, which are secreted by dermal fibroblasts [5,55,56].…”

“…Major skin injuries, resulting from extensive burns, infection or trauma, require medical interventions to heal properly [54]. Therapeutic strategies aim at facilitating the 4 phases of cutaneous wound healing-homeostasis, inflammation, proliferation, remodelingto accelerate wound repair and regeneration [165].…”

Potential of mesenchymal stem cells as topical immunomodulatory cell therapies for ocular surface inflammatory disorders

“…In contrast to developing stem cell therapies for internal organs, the location of the ocular surface makes it an ideal candidate for the noninvasive topical application of stem cells. The advantages of topical application of MSCs, in a similar manner to that discussed for skin healing, 89,90 include: the ability to deliver a concentrated population of cells to a small area, without relying on cell homing mechanisms; the immediate delivery of paracrine signaling molecules to the target area, allowing for more rapid healing; the potential ability to remove the cells after healing if adhered to the delivery vehicle, potentially avoiding allogeneic rejection; and the less invasive nature of the treatment, delivered within a clinic setting rather than surgically.…”

Repairing Injured Skin: Biologics, Skin Substitutes, and Scaffolds: Review

“…In the 1980s, scientists already developed methods to produce in vitro human keratinocyte with fibroblast feeder cells (67).…”