Therapeutic Potential of Stem Cells in Follicle Regeneration

Strengthening the cellular function of dermal fibroblasts and dermal papilla cells using nanovesicles extracted from stem cells using blue light-based photobiomodulation technology

Human dermal fibroblasts (hDFs) play a critical role in skin health by producing extracellular matrix (ECM) components essential for structural stability, while hair follicle dermal papilla cells (HFDPCs) are key to hair follicle growth and regeneration. However, factors such as UV radiation, oxidative stress, and aging impair the functions of hDFs and HFDPCs, leading to decrement in ECM production and skin maintenance and hair loss conditions like alopecia. Recent advances in nanovesicles (NVs) derived from human adipose-derived stem cells (hADSCs) have shown an innovative way in the regenerative medicine field, particularly with promise for enhancing the functionality of diverse cell types. NVs, filled with diverse bioactive molecules, are non-immunogenic, biologically stable, and capable of promoting cellular activities. To further enhance the therapeutic potential of NVs, photobiomodulation (PBM) using blue light has emerged as a promising application. Optimized blue light irradiation can induce moderate levels of reactive oxygen species production in hADSCs, activating signaling pathways that upregulate angiogenic and regenerative markers in hADSCs. In this study, blue light-irradiated NVs demonstrated superior efficacy in promoting hDF proliferation, ECM synthesis, and the functionality of HFDPCs, resulting in enhanced skin maintenance and hair follicle regeneration. This approach presents a safer and more efficient way for treating skin and hair disorders, highlighting the potential use of blue light-irradiated NVs as an innovative therapeutic strategy.

Dahuang-Gancao decoction ameliorates testosterone-induced androgenetic alopecia in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Dahuang-Gancao decoction (DGD) is a traditional Chinese medicinal formula that is recorded in the Synopsis of the Golden Chamber, and is widely used to treat damp-heat in the body. Since the pathological factors of androgenetic alopecia (AGA) also reflect damp-heat blockage, DGD has great potential for the treatment of AGA and has been used effectively in clinical practice.

AIM OF THE STUDY

The aim of the study was to investigate whether external application of DGD could promote the activation and proliferation of hair follicle stem cells (HFSCs) and improve AGA through the Wnt/β-catenin pathway.

MATERIALS AND METHODS

The main chemical components of DGD-contained serum were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and database search. Cell Counting Kit-8 (CCK8) was used to investigate the appropriate concentration. Hair regeneration was assessed by hair growth score and histopathological staining. The proliferation of HFSCs and the activation of Wnt/β-catenin pathway were detected by Western blot, immunofluorescence staining, real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA). The AGA mouse model was induced by external application of testosterone (T). Immunofluorescence staining was performed to localize HFSCs by CK15, followed by staining with Ki67, β-catenin, and Cyclin D1, respectively.

RESULTS

The results illustrated that the 10% DGD group and the 10% DGD + HLY78 group could significantly promote the expression of Wnt10b and β-catenin and the proliferation of HFSCs in vitro, while the 10% DGD + IWR-1 group could reverse the promotion effect of DGD. Animal experiments showed that compared with the model group (T group), DGD promoted hair follicles to enter the anagen phase, as evidenced by an increase in hair growth score, an increase in the number of hair follicles in hematoxylin and eosin (HE) staining, and a significant increase in the ratio of the number of anagen follicles to the total number of hair follicles (AF/AF + TF). In addition, DGD upregulated the expression of Wnt/β-catenin signaling pathway proteins in the skin tissues of AGA mice. It also promoted the proliferation of HFSCs and the expression of β-catenin and Cyclin D1 cytokines in the region of HFSCs.

CONCLUSION

Both oral and external application of DGD can promote the proliferation of HFSCs by activating the Wnt/β-catenin signalling pathway. External application of DGD can promote the hair follicles to enter the anagen phase, which can ameliorate the symptoms of alopecia in AGA mice. Therefore, compared to oral DGD, external application of DGD is an effective and safer way of administration for the treatment of AGA.

Exploring the therapeutic potential of different sources of mesenchymal stem cells: a novel approach to combat burn wound infections

The most prevalent and harmful injuries are burns, which are still a major global health problem. Burn injuries can cause issues because they boost the inflammatory and metabolic response, which can cause organ malfunction and systemic failure. On the other hand, a burn wound infection creates an environment that is conducive to the growth of bacteria and might put the patient at risk for sepsis. In addition, scarring is unavoidable, and this results in patients having functional and cosmetic issues. Wound healing is an amazing phenomenon with a complex mechanism that deals with different types of cells and biomolecules. Cell therapy using stem cells is one of the most challenging treatment methods that accelerates the healing of burn wounds. Since 2000, the use of mesenchymal stem cells (MSCs) in regenerative medicine and wound healing has increased. They can be extracted from various tissues, such as bone marrow, fat, the umbilical cord, and the amniotic membrane. According to studies, stem cell therapy for burn wounds increases angiogenesis, has anti-inflammatory properties, slows the progression of fibrosis, and has an excellent ability to differentiate and regenerate damaged tissue. Figuring out the main preclinical and clinical problems that stop people from using MSCs and then suggesting the right ways to improve therapy could help show the benefits of MSCs and move stem cell-based therapy forward. This review's objective was to assess mesenchymal stem cell therapy's contribution to the promotion of burn wound healing.

Assessing the efficacy of mesotherapy products: Ultra Exo Booster, and Ultra S Line Plus in hair growth: An ex vivo study

In this study, scalp tissues from Korean adults between 20 and 80 without skin disease were used. Scalp tissues were processed, and hair follicles were isolated and cultured with different treatments (including Bioscalp, Ultra Exo Booster, and Ultra S Line Plus) from Ultra V company. Over 12 days, observations and measurements of hair follicle characteristics were recorded at intervals (Days 0, 3, 6, 9, and 12). The study assessed the impact of these substances on hair follicle growth and morphology. Bioscalp, combined with Ultra Exo Booster and Ultra S Line Plus, showed significant hair elongation in ex vivo. Preservation of hair bulb diameter was observed, indicating potential for sustained hair growth by exosome-based products. The hair growth cycle analysis suggested a lower transition to the catagen stage in test products from Ultra V compared to non-treated groups. The research findings indicated that the tested formulations, especially the combination of Bioscalp, Ultra Exo Booster, and Ultra S Line Plus, demonstrated significant effectiveness in promoting hair growth, maintaining the integrity of the hair bulb, and reducing the transition to the catagen stage. The study suggests promising alternative treatments for hair loss, illustrating results that were as good as those of the conventional testing product groups.

Combination of Autophagy and Stem Cell Enhancing Properties of Natural Product Extracts in Human Dermal Papilla Stem Cells

BACKGROUND/AIM

Dermal papilla (DP) stem cells are known for their remarkable regenerative capacity, making them a valuable model for assessing the effects of natural products on cellular processes, including stemness, and autophagy.

MATERIALS AND METHODS

Autophagy and stemness characteristics were assessed using real-time RT-PCR to analyze mRNA levels, along with immunofluorescence and western blot techniques for protein level evaluation.

RESULTS

Butterfly Pea, Emblica Fruits, Kaffir Lime, and Thunbergia Laurifolia extracts induced autophagy in DP cells. Kaffir Lime-treated cells exhibited increase in the OCT4, NANOG, and SOX2 mRNA (6-, 5, and 5.5-fold, respectively), and protein levels (4-, 3-, and 1.5-fold, respectively). All extracts activated the survival protein kinase B (Akt) in DP cells.

CONCLUSION

Natural products are a promising source for promoting hair growth by rejuvenating hair stem cells.

Th22 is the effector cell of thymosin β15-induced hair regeneration in mice

BACKGROUND

Thymosin beta family has a significant role in promoting hair regeneration, but which type of T cells play a key role in this process has not been deeply studied. This research aimed to find out the subtypes of T cell that play key role in hair regeneration mediated by thymosin beta 15 (Tβ15).

METHODS

Ready-to-use adenovirus expressing mouse Tmsb15b (thymosin beta 15 overexpression, Tβ15 OX) and lentivirus-Tβ15 short hairpin RNA (Tβ15 sh) were used to evaluate the role of Tβ15 in hair regeneration and development. The effect of Th22 cells on hair regeneration was further studied by optimized Th22-skewing condition medium and IL-22 binding protein (IL-22BP, an endogenous antagonist of IL-22, also known as IL-22RA2) in both ex vivo culture C57BL/6J mouse skin and BALB/c nude mice transplanted with thymus organoid model.

RESULTS

The results show that Tβ15, the homologous of Tβ4, can promote hair regeneration by increasing the proliferation activity of hair follicle cells. In addition, high-level expression of Tβ15 can not only increase the number of Th22 cells around hair follicles but also accelerate the transformation of hair follicles to maturity. Consistent with the expected results, when the IL-22BP inhibitor was used to interfere with Th22, the process of hair regeneration was blocked.

CONCLUSIONS

In conclusion, Th22 is the key effector cell of Tβ15 inducing hair regeneration. Both Tβ15 and Th22 may be the potential drug targets for hair regeneration.

Status of research on the development and regeneration of hair follicles

Hair loss, or alopecia, is a prevalent condition in modern society that imposes substantial mental and psychological burden on individuals. The types of hair loss, include androgenetic alopecia, alopecia areata, and telogen effluvium; of them, androgenetic alopecia is the most common condition. Traditional treatment modalities mainly involve medical options, such as minoxidil, finasteride and surgical interventions, such as hair transplantation. However, these treatments still have many limitations. Therefore, exploring the pathogenesis of hair loss, specifically focusing on the development and regeneration of hair follicles (HFs), and developing new strategies for promoting hair regrowth are essential. Some emerging therapies for hair loss have gained prominence; these therapies include low-level laser therapy, micro needling, fractional radio frequency, platelet-rich plasma, and stem cell therapy. The aforementioned therapeutic strategies appear promising for hair loss management. In this review, we investigated the mechanisms underlying HF development and regeneration. For this, we studied the structure, development, cycle, and cellular function of HFs. In addition, we analyzed the symptoms, types, and causes of hair loss as well as its current conventional treatments. Our study provides an overview of the most effective regenerative medicine-based therapies for hair loss.

The Current Status and Future Direction of Extracellular Nano-vesicles in the Alleviation of Skin Disorders

Exosomes are extracellular vesicles (EVs) that originate from endocytic membranes. The transfer of biomolecules and biological compounds such as enzymes, proteins, RNA, lipids, and cellular waste disposal through exosomes plays an essential function in cell-cell communication and regulation of pathological and physiological processes in skin disease. The skin is one of the vital organs that makes up about 8% of the total body mass. This organ consists of three layers, epidermis, dermis, and hypodermis that cover the outer surface of the body. Heterogeneity and endogeneity of exosomes is an advantage that distinguishes them from nanoparticles and liposomes and leads to their widespread usage in the remedy of dermal diseases. The biocompatible nature of these extracellular vesicles has attracted the attention of many health researchers. In this review article, we will first discuss the biogenesis of exosomes, their contents, separation methods, and the advantages and disadvantages of exosomes. Then we will highlight recent developments related to the therapeutic applications of exosomes in the treatment of common skin disorders like atopic dermatitis, alopecia, epidermolysis bullosa, keloid, melanoma, psoriasis, and systemic sclerosis.

Therapeutic Potential of Adipose-Derived Stem Cells and Their Secretome in Reversible Alopecias: A Systematic Review

Androgenic alopecia (AGA) and alopecia areata (AA) are two highly prevalent conditions, affecting both men and women of a wide range of ages, which strongly impact their quality of life and self-esteem. Both pathologies are deemed to be reversible, although conventional therapies have shown limited scope and efficacy. New therapeutic approaches, focusing on the degenerative changes that take place in the hair follicle, are needed to achieve better outcomes. For instance, adipose-derived stem cells (ADSC), abundant and easy to obtain, hold great potential in follicular regeneration. ADSCs can be isolated as stromal vascular fraction (SVF) by the enzymatic digestion of the lipoaspirate or as nanofat by the mechanical breakdown of adipocytes. In addition, commercial preparations of the conditioned medium of the ADSCs secretome (ADSC-conditionate medium [CM]) have entered the market as an appealing alternative because of their comparatively lower cost and accessibility. A search was conducted, crossing relevant terms, on PubMed Central and Google Scholar. Criteria for inclusion were studies in the past 10 years on humans with AGA or AA, where either SVF, nanofat, or ADSC-CM was tested as the main treatment. Eleven publications qualified: two studied nanofat, three, ADSC-CM, and six, SVF, either individually or in combination with other therapies. Only one randomized controlled trial (RCT) was found and classified as evidence 2b according to the Sackett scale. The rest were case-control studies or case series with small samples and no control, graded as evidence 3b and 4. A meta-analysis could not be conducted due to the heterogenicity of the study designs. Given the evidence obtained, Level D NICE recommendation was established. However, we consider that the positive findings are sufficiently consistent to support the elaboration of further RCTs that share criteria and methods.

Use of Activated Platelet-Rich Plasma (A-PRP) on Alopecia: A Systematic Review and Meta-Analysis

Alopecia affects perceptions of age, beauty, success, and adaptability. Hair loss can be caused by genetic, physiological, environmental, and immunologic factors. The current treatment for alopecia is varied. This systematic review and meta-analysis evaluates activated platelet rich plasma (A-PRP) for alopecia treatment. The objective of this review was to assess the clinical efficacy and safety of A-PRP injections in alopecia patients. We compared the safety, limitations, and outcomes of A-PRP use with those of previous research on alopecia. We searched PubMed, EMBASE, the Cochrane Database, and Google Scholar for relevant articles. We included all primary clinical studies involving patients that evaluated A-PRP. Twenty-nine articles, which included 864 patients, met the eligibility criteria and were analyzed for qualitative review. Our review found 27 studies that indicated A-PRP was significantly effective in treating alopecia, especially for improving hair density before and after therapy (n = 184, mean difference [MD] = 46.5, I2 = 88%, 95% CI: 29.63, 63.37, P < .00001), as well as when comparison was made between treatment and control groups (n = 88, MD = 31.61, I2 = 80%, 95% CI: 6.99, 56.22, P = .01), and of terminal hair density between treatment and control groups (n = 55, MD = 26.03, I2 = 25%, 95% CI: 8.08, 43.98, P = .004); hair counts after therapy (n = 85, MD = 12.79, I2 = 83%, 95% CI: -5.53, 31.12, P = .0006); promoting hair regrowth; folliculogenesis; reducing hair loss; combining with follicular unit extraction (FUE) surgery; and initiating the hair cycle. Two studies did not report significant results. This is the first systematic review and meta-analysis of A-PRP as a treatment option for alopecia. A-PRP appears to be a promising and safe method for treating alopecia.

LEVEL OF EVIDENCE: 4

Cell Therapy for Androgenetic Alopecia: Elixir or Trick?

Androgenetic alopecia is the most common cause of hair loss aggravated by increased life pressure, tension, and anxiety. Although androgenetic alopecia (AGA) does not significantly effect physical health, it can have serious negative impact on the mental health and quality of life of the patient. Currently, the effect of medical treatment for AGA is not idealistic, stem cell-based regenerative medicine has shown potential for hair regrowth and follicle repair, but the long-term effect and mechanism of stem cell therapy is not quite explicit. In this review, we summarize the methods, efficacy, mechanism, and clinical progress of stem cell therapies for AGA by now, hope it will present a more comprehensive view in this topic.

Innovative Approaches and Advances for Hair Follicle Regeneration

Pathological hair loss (also known as alopecia) and shortage of hair follicle (HF) donors have posed an urgent requirement for HF regeneration. With the revelation of mechanisms in tissue engineering, the proliferation of HFs in vitro has achieved more promising trust for the treatments of alopecia and other skin impairments. Theoretically, HF organoids have great potential to develop into native HFs and attachments such as sweat glands after transplantation. However, since the rich extracellular matrix (ECM) deficiency, the induction characteristics of skin-derived cells gradually fade away along with their trichogenic capacity after continuous cell passaging in vitro. Therefore, ECM-mimicking support is an essential prelude before HF transplantation is implemented. This review summarizes the status of providing various epidermal and dermal cells with a three-dimensional (3D) scaffold to support the cell homeostasis and better mimic in vivo environments for the sake of HF regeneration. HF-relevant cells including dermal papilla cells (DPCs), hair follicle stem cells (HFSCs), and mesenchymal stem cells (MSCs) are able to be induced to form HF organoids in the vitro culture system. The niche microenvironment simulated by different forms of biomaterial scaffold can offer the cells a network of ordered growth environment to alleviate inductivity loss and promote the expression of functional proteins. The scaffolds often play the role of ECM substrates and bring about epithelial-mesenchymal interaction (EMI) through coculture to ensure the functional preservation of HF cells during in vitro passage. Functional HF organoids can be formed either before or after transplantation into the dermis layer. Here, we review and emphasize the importance of 3D culture in HF regeneration in vitro. Finally, the latest progress in treatment trials and critical analysis of the properties and benefits of different emerging biomaterials for HF regeneration along with the main challenges and prospects of HF regenerative approaches are discussed.

Advances in microneedles research based on promoting hair regrowth

Alopecia is the most common and difficult-to-treat hair disorder. It usually brings a significant psychological burden to the patients. With the growing popularity of alopecia, the study of alopecia has gained more attention. Currently, only minoxidil and finasteride have been approved by the FDA for the treatment of alopecia, but the efficacy has always been unsatisfactory. As a new form of transdermal drug delivery, microneedles have been widely used in the treatment of alopecia and have proven to be effective. Microneedles delivery can improve the efficiency of local drug delivery and patients' compliance, which can achieve better therapeutic effects on hair-related diseases. Therefore, microneedles have gained much attention in the field of alopecia and hair regrowth promotion in recent years. This review summarizes the last decade of research on the microneedles delivery design for the treatment of alopecia or promotion of hair regrowth and provides a comprehensive evaluation of this field.

Dendrobium officinale Polysaccharide (DOP) Promotes Hair Regrowth in Testosterone-Induced Bald Mice

BACKGROUND

Androgenetic alopecia can affect up to 70% of males and 40% of females; however, certain therapeutic medications offer partial and transitory improvement but with major side effects. Dendrobium officinale polysaccharide (DOP) has been reported to improve androgen-related hair loss in mice, but the molecular mechanism remains unclear.

OBJECTIVES

To explore the effects of DOP on androgenetic alopecia.

METHODS

In this study, testosterone was subcutaneously administered to shave dorsa skin of mice to establish androgenetic alopecia; the effects of DOP in androgenetic alopecia were explored by DOP administration.

RESULTS

Testosterone treatment extended the time of skin growing dark and hair growing, decreased the mean numbers of follicles in skin tissues, decreased β-catenin and cyclin D1 levels, and elevated testosterone, DHT (dihydrotestosterone), and 5α-reductase levels. In contrast, DOP administration shortened skin growing dark and hair growing times, promoted follicle cell proliferation, increased follicle numbers, increased β-catenin and cyclin D1 levels, and decreased testosterone, DHT, and 5α-reductase levels.

CONCLUSION

DOP application significantly improved testosterone-induced hair follicle miniaturization and hair loss, possibly through affecting the Wnt signaling and hair follicle stem cell functions.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Stem cell secretome as a mechanism for restoring hair loss due to stress, particularly alopecia areata: narrative review

Background

Living organisms are continuously exposed to multiple internal and external stimuli which may influence their emotional, psychological, and physical behaviors. Stress can modify brain structures, reduces functional memory and results in many diseases such as skin disorders like acne, psoriasis, telogen effluvium, and alopecia areata. In this review, we aim to discuss the effect of secretome on treating alopecia, especially alopecia areata. We will shed the light on the mechanism of action of the secretome in the recovery of hair loss and this by reviewing all reported in vitro and in vivo literature.

Main body

Hair loss has been widely known to be enhanced by stressful events. Alopecia areata is one of the skin disorders which can be highly induced by neurogenic stress especially if the patient has a predisposed genetic background. This condition is an autoimmune disease where stress in this case activates the immune response to attack the body itself leading to hair cycle destruction. The currently available treatments include medicines, laser therapy, phototherapy, and alternative medicine therapies with little or no satisfactory results. Regenerative medicine is a new era in medicine showing promising results in treating many medical conditions including Alopecia. The therapeutic effects of stem cells are due to their paracrine and trophic effects which are due to their secretions (secretome).

Conclusion

Stem cells should be more used as an alternative to conventional  therapies due to their positive outcomes. More clinical trials on humans should be done to maximize the dose needed and type of stem cells that must be used to treat alopecia areata.

Application of extracellular vesicles from mesenchymal stem cells promotes hair growth by regulating human dermal cells and follicles

BACKGROUND

Dermal papillae (DP) and outer root sheath (ORS) cells play important roles in hair growth and regeneration by regulating the activity of hair follicle (HF) cells.

AIM

To investigate the effects of human mesenchymal stem cell-derived extracellular vesicles (hMSC-EVs) on DP and ORS cells as well as HFs. EVs are known to regulate various cellular functions. However, the effects of hMSC-EVs on hair growth, particularly on human-derived HF cells (DP and ORS cells), and the possible mechanisms underlying these effects are unknown.

METHODS

hMSC-EVs were isolated and characterized using transmission electron micro scopy, nanoparticle tracking analysis, western blotting, and flow cytometry. The activation of DP and ORS cells was analyzed using cellular proliferation, migration, western blotting, and real-time polymerase chain reaction. HF growth was evaluated ex vivo using human HFs.

RESULTS

Wnt3a is present in a class of hMSC-EVs and associated with the EV membrane. hMSC-EVs promote the proliferation of DP and ORS cells. Moreover, they translocate β-catenin into the nucleus of DP cells by increasing the expression of β-catenin target transcription factors (Axin2, EP2 and LEF1) in DP cells. Treatment with hMSC-EVs also promoted the migration of ORS cells and enhanced the expression of keratin (K) differentiation markers (K6, K16, K17, and K75) in ORS cells. Furthermore, treatment with hMSC-EVs increases hair shaft elongation in cultured human HFs.

CONCLUSION

These findings suggest that hMSC-EVs are potential candidates for further preclinical and clinical studies on hair loss treatment.

Dysregulated behaviour of hair follicle stem cells triggers alopecia and provides potential therapeutic targets

Due to a steady increase in the number of individuals suffering from alopecia, this condition has recently received increasing attention. Alopecia can be caused by various pathological, environmental or psychological factors, eventually resulting in abnormalities in hair follicle (HF) structures or HF regeneration disorders, especially dysregulated hair follicle stem cell (HFSC) behaviour. HFSC behaviour includes activation, proliferation and differentiation. Appropriate HFSC behaviour sustains a persistent hair cycle (HC). HFSC behaviour is mainly influenced by HFSC metabolism, ageing, and the microenvironment. In this review, we summarize recent findings on how HFSC metabolism, ageing and the microenvironment give rise to hair growth disorders, as well as related genes and signalling pathways. Recent research on the application of stem cell-based hair tissue engineering and regenerative medicine to treat alopecia is also summarized. Determining how dysregulated HFSC behaviour underlies alopecia would be helpful in identifying potential therapeutic targets.

Comprehensive Analysis of LncRNA AC010789.1 Delays Androgenic Alopecia Progression by Targeting MicroRNA-21 and the Wnt/β-Catenin Signaling Pathway in Hair Follicle Stem Cells

Background: Androgen alopecia (AGA), the most common type of alopecia worldwide, has become an important medical and social issue. Accumulating evidence indicates that long noncoding RNAs (lncRNAs) play crucial roles in the progression of various human diseases, including AGA. However, the potential roles of lncRNAs in hair follicle stem cells (HFSCs) and their subsequent relevance for AGA have not been fully elucidated. The current study aimed to explore the function and molecular mechanism of the lncRNA AC010789.1 in AGA progression.

Methods: We investigated the expression levels of AC010789.1 in AGA scalp tissues compared with that in normal tissues and explored the underlying mechanisms using bioinformatics. HFSCs were then isolated from hair follicles of patients with AGA, and an AC010789.1-overexpressing HFSC line was produced and verified. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were performed to verify the molecular mechanisms involved.

Results: AC010789.1 overexpression promoted the proliferation and differentiation of HFSCs. Mechanistically, we demonstrated that AC010789.1 overexpression promotes the biological function of HFSCs by downregulating miR-21-5p and TGF-β1 expression but upregulating the Wnt/β-catenin signaling pathway.

Conclusion: These results reveal that overexpression of AC010789.1 suppresses AGA progression via downregulation of hsa-miR-21-5p and TGF-β1 and promotion of the Wnt/β-catenin signaling pathway, highlighting a potentially promising strategy for AGA treatment.

Human Hair Follicle-Derived Mesenchymal Stromal Cells from the Lower Dermal Sheath as a Competitive Alternative for Immunomodulation

Mesenchymal stromal cells (MSCs) have unique immunomodulatory capacities. We investigated hair follicle-derived MSCs (HF-MSCs) from the dermal sheath, which are advantageous as an alternative source because of their relatively painless and minimally risky extraction procedure. These cells expressed neural markers upon isolation and maintained stemness for a minimum of 10 passages. Furthermore, HF-MSCs showed responsiveness to pro-inflammatory environments by expressing type-II major histocompatibility complex antigens (MHC)-II to a lesser extent than adipose tissue-derived MSCs (AT-MSCs). HF-MSCs effectively inhibited the proliferation of peripheral blood mononuclear cells equivalently to AT-MSCs. Additionally, HF-MSCs promoted the induction of CD4+CD25+FOXP3+ regulatory T cells to the same extent as AT-MSCs. Finally, HF-MSCs, more so than AT-MSCs, skewed M0 and M1 macrophages towards M2 phenotypes, with upregulation of typical M2 markers CD163 and CD206 and downregulation of M1 markers such as CD64, CD86, and MHC-II. Thus, we conclude that HF-MSCs are a promising source for immunomodulation.

Regenerative Medicine Treatments for Androgenetic Alopecia

Regenerative medicine and the role of stem cells are being studied for applications in nearly every field of medicine. The pluripotent nature of stem cells underlies their vast potential for treatment of androgenic alopecia. Several advances in recent years have heightened interest in this field, chief among them are the evolution of simpler techniques to isolate regenerative elements and stems cells. These techniques are easy, outpatient procedures with immediate injection, often single session with harvest, and minimal manipulation (usually physical). This paper seeks to critically review the existing data and determine the current evidence and their role in practice.

Therapeutic effects of stem cells in different body systems, a novel method that is yet to gain trust: A comprehensive review

Stem cell therapy has been used to treat several types of diseases, and it is expected that its therapeutic uses shall increase as novel lines of evidence begin to appear. Furthermore, stem cells have the potential to make new tissues and organs. Thus, some scientists propose that organ transplantation will significantly rely on stem cell technology and organogenesis in the future. Stem cells and its robust potential to differentiate into specific types of cells and regenerate tissues and body organs, have been investigated by numerous clinician scientists and researchers for their therapeutic effects. Degenerative diseases in different organs have been the main target of stem cell therapy. Neurodegenerative diseases such as Alzheimer's, musculoskeletal diseases such as osteoarthritis, congenital cardiovascular diseases, and blood cell diseases such as leukemia are among the health conditions that have benefited from stem cell therapy advancements. One of the most challenging parts of the process of incorporating stem cells into clinical practice is controlling their division and differentiation potentials. Sometimes, their potential for  uncontrolled growth will make these cells tumorigenic. Another caveat in this process is the ability to control the differentiation process. While stem cells can easily differentiate into a wide variety of cells,  a paracrine effect controlled activity, being in an appropriate medium will cause abnormal differentiation leading to treatment failure. In this review, we aim to provide an overview of the therapeutic effects of stem cells in diseases of various organ systems. In order to advance this new treatment to its full potential, researchers should focus on establishing methods to control the differentiation process, while policymakers should take an active role in providing adequate facilities and equipment for these projects. Large population clinical trials are a necessary tool that will help build trust in this method. Moreover, improving social awareness about the advantages and adverse effects of stem cell therapy is required to develop a rational demand in the society, and consequently, healthcare systems should consider established stem cell-based therapeutic methods in their treatment algorithms.

Short-Term Efficacy of Autologous Cellular Micrografts in Male and Female Androgenetic Alopecia: A Retrospective Cohort Study

Purpose

Autologous cellular micrografts (ACM) is a novel treatment method in hair loss, and few data are available regarding its efficacy. The present study was carried out to assess the short-term clinical efficacy of a single application of ACM in the treatment of male and female androgenetic alopecia (AGA).

Materials and Methods

This was a single-center retrospective study involving 140 consecutive adults with confirmed AGA, who received a single session of ACM (Regenera Activa®). Efficacy was evaluated 1–6 months after treatment, by analyzing the change of trichometry parameters, which were assessed using TrichoScan digital image analysis.

Results

Depending on the scalp region, there was increase in mean hair density by 4.5–7.12 hair/cm², average hair thickness by 0.96–1.88 μm, % thick hair by 1.74–3.26%, and mean number of follicular units by 1.30–2.77, resulting in an increase of cumulative hair thickness by 0.48–0.56 unit. Additionally, the frontal region showed a significant decrease in % thin hair (−1.81%, p = 0.037) and yellow dots (−1.93 N/cm², p = 0.003). A favorable response was observed in 66.4% of the participants in the frontal region. Further, a gender-specific effect of treatment was observed.

Conclusion

ACM is a promising treatment in AGA with a short-term favorable response observed in up to approximately two-thirds of patients.

Enhancing the Angiogenic and Proliferative Capacity of Dermal Fibroblasts with Mulberry (Morus alba. L) Root Extract

BACKGROUND

Enhancing blood flow and cell proliferation in the hair dermis is critical for treating hair loss. This study was designed to aid the development of alternative and effective solutions to overcome alopecia. Specifically, we examined the effects of Morus alba. L root extract (MARE, which has been used in traditional medicine as a stimulant for hair proliferation) on dermal fibroblasts and other cell types found in the epidermis.

METHODS

We first optimized the concentration of MARE that could be used to treat human dermal fibroblasts (HDFs) without causing cytotoxicity. After optimization, we focused on the effect of MARE on HDFs since these cells secrete paracrine factors related to cell proliferation and angiogenesis that affect hair growth. Conditioned medium (CM) derived from MARE-treated HDFs (MARE HDF-CM) was used to treat human umbilical vein endothelial cells (HUVECs) and hair follicle dermal papilla cells (HFDPCs).

RESULTS

Concentrations of MARE up to 20 wt% increased the expression of proliferative and anti-apoptotic genes in HDFs. MARE HDF-CM significantly improved the tubular structure formation and migration capacity of HUVECs. Additionally, MARE HDF-CM treatment upregulated the expression of hair growth-related genes in HFDPCs. CM collected from MARE-treated HDFs promoted the proliferation of HFDPCs and the secretion of angiogenic paracrine factors from these cells.

CONCLUSION

Since it can stimulate the secretion of pro-proliferative and pro-angiogenic paracrine factors from HDFs, MARE has therapeutic potential as a hair loss preventative.

Amphiregulin promotes hair regeneration of skin-derived precursors via the PI3K and MAPK pathways

Objectives

There are significant clinical challenges associated with alopecia treatment, including poor efficiency of related drugs and insufficient hair follicles (HFs) for transplantation. Skin‐derived precursors (SKPs) exhibit great potential as stem cell‐based therapies for hair regeneration; however, the proliferation and hair‐inducing capacity of SKPs gradually decrease during culturing.

Materials and Methods

We describe a 3D co‐culture system accompanied by kyoto encyclopaedia of genes and genomes and gene ontology enrichment analyses to determine the key factors and pathways that enhance SKP stemness and verified using alkaline phosphatase assays, Ki‐67 staining, HF reconstitution, Western blot and immunofluorescence staining. The upregulated genes were confirmed utilizing corresponding recombinant protein or small‐interfering RNA silencing in vitro, as well as the evaluation of telogen‐to‐anagen transition and HF reconstitution in vivo.

Results

The 3D co‐culture system revealed that epidermal stem cells and adipose‐derived stem cells enhanced SKP proliferation and HF regeneration capacity by amphiregulin (AREG), with the promoted stemness allowing SKPs to gain an earlier telogen‐to‐anagen transition and high‐efficiency HF reconstitution. By contrast, inhibitors of the phosphoinositide 3‐kinase (PI3K) and mitogen‐activated protein kinase (MAPK) pathways downstream of AREG signalling resulted in diametrically opposite activities.

Conclusions

By exploiting a 3D co‐culture model, we determined that AREG promoted SKP stemness by enhancing both proliferation and hair‐inducing capacity through the PI3K and MAPK pathways. These findings suggest AREG therapy as a potentially promising approach for treating alopecia.

Design of In Vitro Hair Follicles for Different Applications in the Treatment of Alopecia-A Review

The hair research field has seen great improvement in recent decades, with in vitro hair follicle (HF) models being extensively developed. However, due to the cellular complexity and number of various molecular interactions that must be coordinated, a fully functional in vitro model of HFs remains elusive. The most common bioengineering approach to grow HFs in vitro is to manipulate their features on cellular and molecular levels, with dermal papilla cells being the main focus. In this study, we focus on providing a better understanding of HFs in general and how they behave in vitro. The first part of the review presents skin morphology with an emphasis on HFs and hair loss. The remainder of the paper evaluates cells, materials, and methods of in vitro growth of HFs. Lastly, in vitro models and assays for evaluating the effects of active compounds on alopecia and hair growth are presented, with the final emphasis on applications of in vitro HFs in hair transplantation. Since the growth of in vitro HFs is a complicated procedure, there is still a great number of unanswered questions aimed at understanding the long-term cycling of HFs without losing inductivity. Incorporating other regions of HFs that lead to the successful formation of different hair classes remains a difficult challenge.

In vitro and clinical evaluation of umbilical cord-derived mesenchymal stromal cell-conditioned media for hair regeneration

BACKGROUND

The field of regenerative medicine may present a non-drug, non-steroid, and non-invasive alternative toward addressing male and female pattern hair loss, a global concern.

OBJECTIVE

The aim was to carry out the in vitro and in vivo safety and efficacy evaluation of human umbilical cord-derived mesenchymal stromal cell-conditioned media (MSC-CM) for hair regeneration.

METHODS

Various in vitro parameters were used to estimate the consistency across various batches of MSC-CM. Total protein content was measured by the Biuret method and antioxidant activity by the 2,2-diphenyl-1-picryl hydrazyl (DPPH) assay. Fourier transform infrared spectroscopy (FTIR) analysis was used to determine spectral signatures and biocompatibility was carried out by the Neutral Red Uptake (NRU) and Sulforhodamine B (SRB) assays. In vivo safety and efficacy was evaluated in an experimental pilot study on 15 volunteers.

RESULTS

The in vitro results confirmed stability in the protein content (7 mg/ml), antioxidant activity (49.50%), and FTIR fingerprints of the MSC-CM. In the biocompatibility experiments by both SRB and NRU methods, no IC₅₀ value could be derived at 100% concentration indicating safety at the cellular level. The in vivo results indicated safety with no side effects or adverse reactions, while 86.6% of the subjects experienced a positive effect of hair regeneration.

CONCLUSION

MSC-CM comprises a rich cocktail of physiologically balanced growth factors, cytokines, and beneficial proteins which may explain the bioactivity and mechanism of action in hair regrowth. This may indicate a biocompatible, gentle, and safe regenerative approach to address hair loss.

Establishment of an Efficient Primary Culture System for Human Hair Follicle Stem Cells Using the Rho-Associated Protein Kinase Inhibitor Y-27632

Background

Hair follicle tissue engineering is a promising strategy for treating hair loss. Human hair follicle stem cells (hHFSCs), which play a key role in the hair cycle, have potential applications in regenerative medicine. However, previous studies did not achieve efficient hHFSC expansion in vitro using feeder cells. Therefore, there is a need to develop an efficient primary culture system for the expansion and maintenance of hHFSCs.

Methods

The hHFSCs were obtained by two-step proteolytic digestion combined with microscopy. The cell culture dishes were coated with human fibronectin and inoculated with hHFSCs. The hHFSCs were harvested using a differential enrichment procedure. The effect of Rho-associated protein kinase (ROCK) inhibitor Y-27632, supplemented in keratinocyte serum-free medium (K-SFM), on adhesion, proliferation, and stemness of hHFSCs and the underlying molecular mechanisms were evaluated.

Results

The hHFSCs cultured in K-SFM, supplemented with Y-27632, exhibited enhanced adhesion and proliferation. Additionally, Y-27632 treatment maintained the stemness of hHFSCs and promoted the ability of hHFSCs to regenerate hair follicles in vivo. However, Y-27632-induced proliferation and stemness in hHFSCs were conditional and reversible. Furthermore, Y-27632 maintained propagation and stemness of hHFSCs through the ERK/MAPK pathway.

Conclusion

An efficient short-term culture system for primary hHFSCs was successfully established using human fibronectin and the ROCK inhibitor Y-27632, which promoted the proliferation, maintained the stemness of hHFSCs and promoted the ability to regenerate hair follicles in vivo. The xenofree culturing method used in this study provided a large number of high-quality seed cells, which have applications in hair follicle tissue engineering and stem cell therapy.

The Effect of Conditioned Media From Human Adipocyte-Derived Mesenchymal Stem Cells on Androgenetic Alopecia After Nonablative Fractional Laser Treatment

BACKGROUND

The conditioned media from adipocyte-derived mesenchymal stem cells-conditioned media (ADSC-CM) contains cytokines and growth factors that stimulate hair regeneration.

OBJECTIVE

We evaluated the efficacy and safety of human ADSC-CM treatment on patients who underwent nonablative fractional laser for the treatment of androgenetic alopecia (AGA).

MATERIALS AND METHODS

Thirty patients who underwent nonablative fractional laser treatment were topically administered either ADSC-CM or placebo solution. As a primary outcome, phototrichograms were taken to measure changes in hair density at each visit. In addition, global improvement scores (GISs) were compared by clinical digital photographs, which were taken at the initial and final visits, and assessed by 2 independent dermatologists. Finally, the investigator's improvement score was measured by questionnaire response during the final visit.

RESULTS

Hair density comparisons during the treatment period revealed that the ADSC-CM group had significantly higher final densities compared with the placebo group. The GIS of the ADSC-CM group was also significantly higher than the placebo group. Finally, no adverse effects associated with the application of ADSC-CM were noted during the study.

CONCLUSION

The application of ADSC-CM after nonablative fractional laser treatment accelerated increases in hair density and volume in AGA patients.

Evidence-based indications of platelet-rich plasma therapy

Introduction: Platelet-rich plasma (PRP) is an autologous blood-derived product that contains platelet concentrations at least 2/3 times above the normal level and includes platelet-related growth factors. The concept of PRP began in the 1970s in the field of hematology to treat patients with thrombocytopenia. In the 1980s and 1990s, PRP began to be used in surgical procedures such as maxillofacial surgery and plastic surgery. Since then, PRP had been used in orthopedic procedures, cardiac surgery, sports injuries, plastic surgery, gynecology, urology, and more recently in medical esthetics. Areas covered: This review analyzes the mechanisms of action, current indications, clinical evidence, safety and future directions of PRP in the management of various medical conditions. The literature search methodology included using medical subject headings terms to search in PubMed. Articles used were screened and critically appraised by the coauthors of this review. Expert Opinion: Platelet-rich plasma is a therapeutic option used to treat many medical conditions. PRP could be used alone or in combination with other procedures. The effectiveness and safety of PRP has been demonstrated in many medical scenarios, however there is limited availability of large randomized clinical trials.

miR-140-5p in Small Extracellular Vesicles From Human Papilla Cells Stimulates Hair Growth by Promoting Proliferation of Outer Root Sheath and Hair Matrix Cells

The application of dermal papilla cells to hair follicle (HF) regeneration has attracted a great deal of attention. However, cultured dermal papilla cells (DPCs) tend to lose their capacity to induce hair growth during passage, restricting their usefulness. Accumulating evidence indicates that DPCs regulate HF growth mainly through their unique paracrine properties, raising the possibility of therapies based on extracellular vesicles (EVs). In this study, we explored the effects of EVs from high- and low-passage human scalp follicle dermal papilla cells (DP-EVs) on activation of hair growth, and investigated the underlying mechanism. DP-EVs were isolated by ultracentrifugation and cultured with human scalp follicles, hair matrix cells (MxCs), and outer root sheath cells (ORSCs), and we found low-passage DP-EVs accelerated HF elongation and cell proliferation activation. High-throughput miRNA sequencing and bioinformatics analysis identified 100 miRNAs that were differentially expressed between low- (P3) and high- (P8) passage DP-EVs. GO and KEGG pathway analysis of 1803 overlapping target genes revealed significant enrichment in the BMP/TGF-β signaling pathways. BMP2 was identified as a hub of the overlapping genes. miR-140-5p, which was highly enriched in low-passage DP-EVs, was identified as a potential regulator of BMP2. Direct repression of BMP2 by miR-140-5p was confirmed by dual-luciferase reporter assay. Moreover, overexpression and inhibition of miR-140-5p in DP-EVs suppressed and increased expression of BMP signaling components, respectively, indicating that this miRNA plays a critical role in hair growth and cell proliferation. DP-EVs transport miR-140-5p from DPCs to epithelial cells, where it downregulates BMP2. Therefore, DPC-derived vesicular miR-140-5p represents a therapeutic target for alopecia.

Advanced Medical Therapies in the Management of Non-Scarring Alopecia: Areata and Androgenic Alopecia

Alopecia is a challenging condition for both physicians and patients. Several topical, intralesional, oral, and surgical treatments have been developed in recent decades, but some of those therapies only provide partial improvement. Advanced medical therapies are medical products based on genes, cells, and/or tissue engineering products that have properties in regenerating, repairing, or replacing human tissue. In recent years, numerous applications have been described for advanced medical therapies. With this background, those therapies may have a role in the treatment of various types of alopecia such as alopecia areata and androgenic alopecia. The aim of this review is to provide dermatologists an overview of the different advanced medical therapies that have been applied in the treatment of alopecia, by reviewing clinical and basic research studies as well as ongoing clinical trials.

Optogenetically Controlled TrkA Activity Improves the Regenerative Capacity of Hair-Follicle-Derived Stem Cells to Differentiate into Neurons and Glia

Hair-follicle-derived stem cells (HSCs) originating from the bulge region of the mouse vibrissa hair follicle are able to differentiate into neuronal and glial lineage cells. The tropomyosin receptor kinase A (TrkA) receptor that is expressed on these cells plays key roles in mediating the survival and differentiation of neural progenitors as well as in the regulation of the growth and regeneration of different neural systems. In this study, the OptoTrkA system is introduced, which is able to stimulate TrkA activity via blue-light illumination in HSCs. This allows to determine whether TrkA signaling is capable of influencing the proliferation, migration, and neural differentiation of these somatic stem cells. It is found that OptoTrkA is able to activate downstream molecules such as ERK and AKT with blue-light illumination, and subsequently able to terminate this kinase activity in the dark. HSCs with OptoTrkA activity show an increased ability for proliferation and migration and also exhibited accelerated neuronal and glial cell differentiation. These findings suggest that the precise control of TrkA activity using optogenetic tools is a viable strategy for the regeneration of neurons from HSCs, and also provides a novel insight into the clinical application of optogenetic tools in cell-transplantation therapy.

Advances in Stem Cell-Based Therapy for Hair Loss

OBJECTIVE

Hair loss is a quite common condition observed in both men and women. Pattern hair loss also known as androgenetic alopecia is the most common form of hair loss that is thought to affect up to 80% of Caucasian men and up to 40% of Caucasian women by age of 70, and it can have quite devastating consequences on one's well-being, including lower self-esteem, depression and lower quality of life. To date there have only been 2 FDA approved medications, minoxidil and finasteride, but their effects are often unsatisfactory and temporary, in addition to having various adverse effects. Stem cell-based therapies have recently received lots of attention as potential novel treatments that focus on reactivating hair follicle stem cells and in this way enhance hair follicle growth, regeneration and development. Stem cell-based therapy approaches include stem cell transplant, stem cell-derived conditioned medium and stem cell-derived exosomes.

MATERIALS AND METHODS

A combination of following key words was utilized for a PubMed search: cell-based therapy, hair loss, alopecia, hair regrowth; abstracts were screened and included based on the content relevant to hair loss and stem-cell based therapy.

RESULTS

Preclinical research utilizing these approaches has blossomed in the past decade along with a more limited number of clinical studies, overall demonstrating very promising findings.

CONCLUSION

However, stem cell-based therapies for hair loss are still at their infancy and more robust clinical studies are needed to better evaluate their mechanisms of action, efficacy, safety, benefits and limitations. In this review, we provide the resources to the latest preclinical studies and a more detailed description of the latest clinical studies concerning stem cell-based therapies in hair loss.

A Concise Review on Tissue Engineered Artificial Skin Grafts for Chronic Wound Treatment: Can We Reconstruct Functional Skin Tissue In Vitro?

Chronic wounds occur as a consequence of a prolonged inflammatory phase during the healing process, which precludes skin regeneration. Typical treatment for chronic wounds includes application of autografts, allografts collected from cadaver, and topical delivery of antioxidant, anti-inflammatory, and antibacterial agents. Nevertheless, the mentioned therapies are not sufficient for extensive or deep wounds. Moreover, application of allogeneic skin grafts carries high risk of rejection and treatment failure. Advanced therapies for chronic wounds involve application of bioengineered artificial skin substitutes to overcome graft rejection as well as topical delivery of mesenchymal stem cells to reduce inflammation and accelerate the healing process. This review focuses on the concept of skin tissue engineering, which is a modern approach to chronic wound treatment. The aim of the article is to summarize common therapies for chronic wounds and recent achievements in the development of bioengineered artificial skin constructs, including analysis of biomaterials and cells widely used for skin graft production. This review also presents attempts to reconstruct nerves, pigmentation, and skin appendages (hair follicles, sweat glands) using artificial skin grafts as well as recent trends in the engineering of biomaterials, aiming to produce nanocomposite skin substitutes (nanofilled polymer composites) with controlled antibacterial activity. Finally, the article describes the composition, advantages, and limitations of both newly developed and commercially available bioengineered skin substitutes.

Human Hair Outer Root Sheath Cells and Platelet-Lysis Exosomes Promote Hair Inductivity of Dermal Papilla Cell

BACKGROUND

Hair loss is a prevalent medical problem in both men and women. Maintaining the potential hair inductivity of dermal papilla cells (DPCs) during cell culture is the main factor in hair follicle morphogenesis and regeneration. The present study was conducted to compare the effects of different concentrations of human hair outer root sheath cell (HHORSC) and platelet lysis (PL) exosomes to maintain hair inductivity of the human dermal papilla cells (hDPCs).

METHODS

In this study, hDPCs and HHORSCs were isolated from healthy hair samples. Specific markers of hDPCs (versican, α-SMA) and HHORSCs (K15) were evaluated using flow cytometric and immunocytochemical techniques. The exosomes were isolated from HHORSCs and PL with ultracentrifugation technique. Western blot was used to detect specific markers of HHORSCs and PL exosomes. Particle size and distribution of the exosomes were analyzed by NanoSight dynamic light NanoSight Dynamic Light Scattering. Different methods such as proliferation test (MTS assay), migration test (Transwell assay) were used to evaluate the effects of different concentrations of exosomes (2,550,100 µg/ml) derived from HHORSC and PL on hDPCs. Expression of specific genes in the hair follicle inductivity, including ALP, versican and α-SMA were also evaluated using real time-PCR.

RESULTS

The flow cytometry of the specific cytoplasmic markers of the hDPCs and HHORSCs showed expression of versican (77%), α-SMA (55.2%) and K15 (73.2%). The result of particle size and distribution of the exosomes were analyzed by NanoSight dynamic light NanoSight Dynamic Light Scattering, which revealed the majority of HHORSC and PL exosomes were 30-150 nm. For 100 µg/ml of HHORSC exosomes, the expressions of ALP, versican and α-SMA proteins respectively increased by a factor of 2.1, 1.7and 1.3 compared to those in the control group.

CONCLUSION

In summary, we applied HHORSC exosomes as a new method to support hair inductivity of dermal papilla cells and improve the outcome for the treatment of hair loss.

Systematic Review of Platelet-Rich Plasma Use in Androgenetic Alopecia Compared with Minoxidil®, Finasteride®, and Adult Stem Cell-Based Therapy

The number of articles evaluating platelet-rich plasma (PRP) efficacy in androgenic alopecia (AGA) have exponentially increased during the last decade. A systematic review on this field was performed by assessing in the selected studies the local injections of PRP compared to any control for AGA. The protocol was developed in accordance with the Preferred Reporting for Items for Systematic Reviews and Meta-Analyses-Protocols (PRISMA-P) guidelines. A multistep search of the PubMed, MEDLINE, Embase, PreMEDLINE, Ebase, CINAHL, PsycINFO, Clinicaltrials.gov, Scopus database, and Cochrane databases was performed to identify studies on hair loss treatment with platelet-rich plasma. Of the 163 articles initially identified, 123 articles focusing on AGA were selected and, consequently, only 12 clinical trials were analyzed. The studies included had to match predetermined criteria according to the PICOS (patients, intervention, comparator, outcomes, and study design) approach. In total, 84% of the studies reported a positive effect of PRP for AGA treatment. Among them, 50% of the studies demonstrated a statistically significant improvement using objective measures and 34% of the studies showed hair density and hair thickness improvement, although no p values or statistical analysis was described. In total, 17% of the studies reported greater improvement in lower-grade AGA, while 8% noted increased improvement in higher-grade AGA. Only 17% of the studies reported that PRP was not effective in treating AGA. The information analyzed highlights the positive effects of PRP on AGA, without major side effects and thus it be may considered as a safe and effective alternative procedure to treat hair loss compared with Minoxidil® and Finasteride®.

Autologous Micrografts from Scalp Tissue: Trichoscopic and Long-Term Clinical Evaluation in Male and Female Androgenetic Alopecia

Tissue engineering in hair regrowth aims to develop innovative and not-invasive procedures to advance the hair regrowth. A placebo-controlled, randomized, evaluator-blinded, half-head group study to compare hair regrowth with micrografts containing human hair follicle mesenchymal stem cells (HF-MSCs) vs. placebo was reported. After 58 weeks, 27 patients displayed in the targeted area an increase of hair count and hair density, respectively, of 18.0 hairs per 0.65 cm2 and 23.3 hairs per cm2 compared with baseline, while the control area displayed a mean decrease of 1.1 hairs per 0.65 cm2 and 0.7 hairs per cm2 (control vs. treatment: P < 0.0001). After 26 months, 6 patients revealed dynamic hair loss and were retreated. More broad controlled examinations are required. HF-MSCs contained in micrografts may represent a safe and viable treatment alternative against hair loss.

Advances in Regenerative Stem Cell Therapy in Androgenic Alopecia and Hair Loss: Wnt pathway, Growth-Factor, and Mesenchymal Stem Cell Signaling Impact Analysis on Cell Growth and Hair Follicle Development

The use of stem cells has been reported to improve hair regrowth in several therapeutic strategies, including reversing the pathological mechanisms, that contribute to hair loss, regeneration of hair follicles, or creating hair using the tissue-engineering approach. Although various promising stem cell approaches are progressing via pre-clinical models to clinical trials, intraoperative stem cell treatments with a one-step procedure offer a quicker result by incorporating an autologous cell source without manipulation, which may be injected by surgeons through a well-established clinical practice. Many authors have concentrated on adipose-derived stromal vascular cells due to their ability to separate into numerous cell genealogies, platelet-rich plasma for its ability to enhance cell multiplication and neo-angiogenesis, as well as human follicle mesenchymal stem cells. In this paper, the significant improvements in intraoperative stem cell approaches, from in vivo models to clinical investigations, are reviewed. The potential regenerative instruments and functions of various cell populaces in the hair regrowth process are discussed. The addition of Wnt signaling in dermal papilla cells is considered a key factor in stimulating hair growth. Mesenchymal stem cell-derived signaling and growth factors obtained by platelets influence hair growth through cellular proliferation to prolong the anagen phase (FGF-7), induce cell growth (ERK activation), stimulate hair follicle development (β-catenin), and suppress apoptotic cues (Bcl-2 release and Akt activation).