Conventional and novel stem cell based therapies for androgenic alopecia

Stem Cells and Cloning: Advances and Applications Dovepress open access to scientific and medical research REVIEW Stem Cells and Cloning: Advances and Applications downloaded from https://www.dovepress.com/ by 98.0.17.93 on 24-May-2020 For personal use only. Open Access Full Text Article Conventional and novel stem cell based therapies for androgenic alopecia This article was published in the following Dove Press journal: Stem Cells and Cloning: Advances and Applications 31 August 2017 Number of times this article has been viewed Dodanim Talavera-Adame 1 Daniella Newman 2 Nathan Newman 1 1 American Advanced Medical Corp. (Private Practice), Beverly Hills, CA, 2 Western University of Health Sciences, Pomona, CA, USA Video abstract Introduction Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use: http://youtu.be/MoU6GAW9BRk Correspondence: Nathan Newman 9301 Wilshire Blvd, Suite 303, Beverly Hills, CA 90210, USA Tel +1 310 273 3344 Fax +1 310 273 7651 Email The prevalence of androgenic alopecia (AGA) increases with age, and is estimated to affect about 80% of Caucasian men.1 Female AGA, also known as female pattern hair loss, affects 32% of women in the ninth decade of life.2 The consumer market for products that promote hair growth has been increasing dramatically.3 These products promote hair regeneration based on the knowledge about the hair follicle (HF) cycle.4,5 However, in most cases, the mechanisms of action of these products are not well characterized and the results are variable or with undesirable side effects.6 At present, only two treatments for AGA have been approved by the US Food and Drug Administration (FDA): Minoxidil and Finasteride.7–10Although these medications have proved to be effective in some cases, their use is limited by their side effects.11,12 With the emergence of stem cells (SCs), many mechanisms that lead to tissue regeneration have been discovered.13 Hair regeneration has become one of the targets for SC technologies to restore the hair in AGA.14 Several SC factors such as peptides exert essential signals to promote hair regrowth.15,16 Some of these signals stimulate differentiation of SCs to keratinocytes which are important for HF growth.17 Other signals can stimulate dermal papilla cells (DPCs) that promote SC proliferation in the HF.18,19 In this review, we describe HF characteristics and discuss different therapies used currently for AGA and possible novel agents for hair regeneration. These therapies include FDA-approved 11 submit your manuscript | www.dovepress.com Stem Cells and Cloning: Advances and Applications 2017:10 11–19 Dovepress © 2017 Talavera-Adame et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms. php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php). http://dx.doi.org/10.2147/SCCAA.S138150 Powered by TCPDF (www.tcpdf.org) Abstract: The prevalence of androgenic alopecia (AGA) increases with age and it affects both men and women. Patients diagnosed with AGA may experience decreased quality of life, depression, and feel self-conscious. There are a variety of therapeutic options ranging from prescription drugs to non-prescription medications. Currently, AGA involves an annual global market revenue of US$4 billion and a growth rate of 1.8%, indicating a growing consumer market. Although natural and synthetic ingredients can promote hair growth and, therefore, be useful to treat AGA, some of them have important adverse effects and unknown mechanisms of action that limit their use and benefits. Biologic factors that include signaling from stem cells, dermal papilla cells, and platelet-rich plasma are some of the current therapeutic agents being studied for hair restoration with milder side effects. However, most of the mechanisms exerted by these factors in hair restoration are still being researched. In this review, we analyze the therapeutic agents that have been used for AGA and emphasize the potential of new therapies based on advances in stem cell technologies and regenerative medicine. Keywords: stem cells, stem cell therapies, hair follicle, dermal papilla, androgenic alopecia, laser, hair regeneration Dovepress Talavera-Adame et al BMP receptor activation in DPCs similar to those signals that promote survival of MSCs in human embryoid bodies composed of multipotent cells.24,25 DPCs have been derived from pluripotent SCs in an attempt to study their potential for hair regeneration in vitro and in vivo.27 Together, dermal blood vessels and DPCs orchestrate a suitable microenvironment for the growth and survival of HFSCs.28,29 Interestingly, the expression of Forkhead box C1 regulates the quiescence of HFSCs located in the bulge region (Figure 1).30 HFSCs are quiescent during mid-anagen and maintain this stage until the next hair cycle.29,30 However, during early anagen stage, these cells undergo a short proliferative phase in which they self-renew and produce new hair.30 Therefore, the bulge region constitutes a SC niche that makes multiple signals toward quiescence or proliferation stages.30–34 It is known that fibroblasts and adipocyte signals are able to inhibit the proliferation of HFSCs.34 Additionally, BMP6 and fibroblast growth factor 18 (FGF18) from bulge cells exert inhibitory effects on HFSC proliferation.34 Dihydrotestosterone (DHT) also inhibits HF growth.35 Agents that reduce DHT, such as Finasteride, promote hair regrowth by inhibiting Type II 5α-reductase.8,14,36 In contrast to these inhibitory effects, DPCs located at the base of the HF provide activation signals (Figure 1).18,34 The crosstalk between DPCs and HFSCs leads to inhibition of inhibitory effects with the resultant cell HF and SC niche The HF undergoes biologic changes from an actively growing stage (anagen) to a quiescent stage (telogen) with an intermediate remodeling stage (catagen).4 HFSCs are located in the bulge region of the follicle and they interact with mesenchymal SCs (MSCs) located in the dermal papilla (DP).18 These signal exchanges promote activation of some cellular pathways that are essential for DPC growth, function, and survival, such as the activation of   Wnt signaling pathway.19–21 Other signals, such as those from endothelial cells (ECs) located at the DP, are also essential for HF maintenance.22 EC dysfunction that impairs adequate blood supply may limits or inhibits hair growth.22 For instance, Minoxidil, a synthetic age (...truncated)