Extracellular vesicles derived from MSCs activates dermal papilla cell in vitro and promotes hair follicle conversion from telogen to anagen in mice

Stimulation of mouse hair regrowth by exosomes derived from human umbilical cord mesenchymal stem cells

BACKGROUND

There is an urgent need for new treatments to solve hair loss problem. As mesenchymal stem cells were proved to have effects on promoting tissue repair and regeneration, in which the exosome plays a vital role, we aim to investigate the influence of umbilical cord mesenchymal stem cells exosome (UCMSC-Exos) on hair growth and its mechanism.

METHODS

The hUCMSC-Exos were extracted by ultracentrifugation. Primary fibroblasts were cultured with or without hUCMSC-Exos and cell proliferation was evaluated by CCK-8 assay. C57BL/6 mice model of depilation-induced hair regrowth was treated with either hUCMSC-Exos (200 μg/mL) or PBS on one side of the dorsal back. Real time quantitative PCR, flow cytometry analysis, immunohistochemistry and Immunofluorescent staining were used to analyze the regulative effect of hUCMSC-Exos on hair follicle stem/progenitor cells and Wnt/β-catenin pathway.

RESULTS

The proliferation of fibroblasts incubated with hUCMSC-Exos at the concentration of 200 μg/mL was greater than other groups. Treatment with hUCMSC-Exos resulted in rapid reentry into anagen. Hair follicle stem/progenitor cell markers (K15, Lgr5, Lgr6, CD34 and Lrig1) and Wnt/β-catenin pathway related factors (Wnt5, Lef1, Lrp5 and β-catenin) were increased in hUCMSC-Exos-injected region.

CONCLUSION

hUCMSC-Exos promote fibroblasts proliferation and accelerate mouse hair regrowth by upregulating hair follicle stem/progenitor cell and Wnt/β-catenin pathway, which suggests potential therapeutic approaches for hair loss disorders.

Improvement of androgenic alopecia by extracellular vesicles secreted from hyaluronic acid-stimulated induced mesenchymal stem cells

BACKGROUND

Androgenetic alopecia (AGA) is a common form of hair loss. Androgens, such as testosterone and dihydrotestosterone, are the main causes of AGA. Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) can reduce AGA. However, preparing therapeutic doses of MSCs for clinical use is challenging. Induced pluripotent stem cell-derived MSCs (iMSCs) are homogenous and easily expandable, enabling scalable production of EVs. Hyaluronic acid (HA) can exert various functions including free radical scavenging, immune regulation, and cell migration. Herein, we examined whether hyaluronic acid (HA) stimulation of iMSCs could produce EVs with enhanced therapeutic outcomes for AGA.

METHODS

EVs were collected from iMSCs primed with HA (HA-iMSC-EVs) or without HA (iMSC-EVs). The characteristics of EVs were examined using dynamic light scattering, cryo-transmission electron microscopy, immunoblotting, flow cytometry, and proteomic analysis. In vitro, we compared the potential of EVs in stimulating the survival of hair follicle dermal papilla cells undergoing testosterone-mediated AGA. Additionally, the expression of androgen receptor (AR) and relevant growth factors as well as key proteins of Wnt/β-catenin signaling pathway (β-catenin and phosphorylated GSK3β) was analyzed. Subsequently, AGA was induced in male C57/BL6 mice by testosterone administration, followed by repeated injections of iMSC-EVs, HA-iMSC-EVs, finasteride, or vehicle. Several parameters including hair growth, anagen phase ratio, reactivation of Wnt/β-catenin pathway, and AR expression was examined using qPCR, immunoblotting, and immunofluorescence analysis.

RESULTS

Both types of EVs showed typical characteristics for EVs, such as size distribution, markers, and surface protein expression. In hair follicle dermal papilla cells, the mRNA levels of AR, TGF-β, and IL-6 increased by testosterone was blocked by HA-iMSC-EVs, which also contributed to the augmented expression of trophic genes related to hair regrowth. However, no notable changes were observed in the iMSC-EVs. Re-activation of Wnt/β-catenin was observed in HA-iMSC-EVs but not in iMSC-EVs, as shown by β-catenin stabilization and an increase in phosphorylated GSK3β. Restoration of hair growth was more significant in HA-iMSC-EVs than in iMSC-EVs, and was comparable to that in mice treated with finasteride. Consistently, the decreased anagen ratio induced by testosterone was reversed by HA-iMSC-EVs, but not by iMSC-EVs. An increased expression of hair follicular β-catenin protein, as well as the reduction of AR was observed in the skin tissue of AGA mice receiving HA-iMSC-EVs, but not in those treated with iMSC-EVs.

CONCLUSIONS

Our results suggest that HA-iMSC-EVs have potential to improve AGA by regulating growth factors/cytokines and stimulating AR-related Wnt/β-catenin signaling.

Hybrid hair follicle stem cell extracellular vesicles co-delivering finasteride and gold nanoparticles for androgenetic alopecia treatment

Androgenetic alopecia (AGA) is a non-fatal disease prevalent worldwide. However, mixed efficacy has been observed among different therapies for hair regrowth in AGA patients. Thus, a nano-platform with synergistic treatments based on a hybrid extracellular vesicle encapsulating gold nanoparticles (AuNPs) and finasteride (Hybrid/Au@Fi) was constructed through membrane fusion between hair follicle stem cell (HFSC)-derived extracellular vesicles and liposomes. These hybrid vesicles (HVs) not only fuel hair regrowth by providing cellular signals in extracellular vesicles, but also improve storage stability, follicle retention, and drug encapsulation efficiency (EE%) for finasteride inhibiting 5α-reductase, and nano-size AuNPs that simulate low-level laser therapy (LLLT) with similar photothermal effects in vitro. The EE% of finasteride in these HVs reached 45.33%. The dual administration of these extracellular vesicles and finasteride showed a strong synergistic effect on HFSCs in vitro. In an AGA mouse model, once-daily topical Hybrid/Au@Fi (115.07 ± 0.32 nm, -7.50 ± 1.68 mV) gel led to a faster transition of hair follicles (HFs) from the catagen to the anagen, increased hair regrowth coverage, and higher quality of regrowth hair, compared to once-daily 5% minoxidil treatment. Compared to topical minoxidil, the multifaceted synergistic therapy of Hybrid/Au@Fi through topical administration offers a new option for intractable AGA patients with low side effects.

Effectiveness of Exosome Treatment in Androgenetic Alopecia: Outcomes of a Prospective Study

OBJECTIVE

Harnessing the regenerative capabilities of stem cell-derived exosomes holds great promise for developing novel hair growth therapies, offering hope for individuals experiencing hair loss or alopecia. This aimed to elucidate the effect of "foreskin-derived mesenchymal stromal cells derived exosome" injection into the scalp on hair density in patients with androgenetic alopecia and the contribution of this treatment on patient satisfaction.

METHOD

This prospective study included 30 male patients, aged between 22 and 65, with hair type III-VI according to the Norwood-Hamilton scale. Characterization of the stem cell exosomes was performed with the nanoparticle tracking analysis (NTA), hair densities were calculated via digital imaging analysis, and patient satisfaction was questioned with a modified survey.

RESULTS

NTA results showed a characteristic distribution of peaks for exosomes 139.7 ± 2.3 nm in diameter. A statistically significant increase in hair density was observed in the 4th and 12th weeks after treatment (p < 0.05). Patient-reported satisfaction revealed a statistically significant difference in the answers given in the 12th week compared to the 4th week (p < 0.05). No side effects or complications were observed after exosome injection.

CONCLUSION

Foreskin-derived mesenchymal stromal cells derived exosome injection increased hair density, with sustained patient satisfaction throughout the study. The exosome application resulted in no side effects.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. 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 .

The role of mesenchymal stem cells in cancer and prospects for their use in cancer therapeutics

Mesenchymal stem cells (MSCs) are recruited by malignant tumor cells to the tumor microenvironment (TME) and play a crucial role in the initiation and progression of malignant tumors. This role encompasses immune evasion, promotion of angiogenesis, stimulation of cancer cell proliferation, correlation with cancer stem cells, multilineage differentiation within the TME, and development of treatment resistance. Simultaneously, extensive research is exploring the homing effect of MSCs and MSC-derived extracellular vesicles (MSCs-EVs) in tumors, aiming to design them as carriers for antitumor substances. These substances are targeted to deliver antitumor drugs to enhance drug efficacy while reducing drug toxicity. This paper provides a review of the supportive role of MSCs in tumor progression and the associated molecular mechanisms. Additionally, we summarize the latest therapeutic strategies involving engineered MSCs and MSCs-EVs in cancer treatment, including their utilization as carriers for gene therapeutic agents, chemotherapeutics, and oncolytic viruses. We also discuss the distribution and clearance of MSCs and MSCs-EVs upon entry into the body to elucidate the potential of targeted therapies based on MSCs and MSCs-EVs in cancer treatment, along with the challenges they face.

Triethylene Glycol Squalene Improves Hair Regeneration by Maintaining the Inductive Capacity of Human Dermal Papilla Cells and Preventing Premature Aging

De novo hair follicle (HF) regeneration, achieved through the replenishment of the dermal papilla (DP), acknowledged as the principal orchestrator of the hair growth cycle, is emerging as a prospective therapeutic intervention for alopecia. Nonetheless, multiple attempts have shown that these cells lose key inductive properties when cultured in a two-dimensional (2D) monolayer, leading to precocious senescence engendered by oxidative stress and inflammatory processes. Consequently, the three-dimensional (3D) spheroid technique is presently widely employed for DP cell culture. Nevertheless, substantiating the regenerative potential of these cells within the hair follicle (HF) milieu remains a challenge. In this current study, we aim to find a new approach to activate the inductive properties of DP cells. This involves the application of hair-growth-stimulating agents that not only exhibit concurrent protective efficacy against the aging process but also induce HF regeneration. To achieve this objective, we initially synthesized a novel highly amphiphilic derivative derived from squalene (SQ), named triethylene glycol squalene (Tri-SQ). Squalene itself is a potent antioxidant and anti-inflammatory compound traditionally employed as a drug carrier for alopecia treatment. However, its application is limited due to its low solubility. Subsequently, we applied this newly synthesized derivative to DP cells. The data obtained demonstrated that the derivative exhibits robust antioxidant and anti-inflammatory activities while concurrently promoting the expression of genes associated with hair growth. Moreover, to further assess the hair regrowth inductive properties of DP cells, we cultured the cells and treated them with Tri-SQ within a 3D spheroid system. Subsequently, these treated cells were injected into the previously depilated dorsal area of six-week-old male C57BL/6 mice. Results revealed that 20 days postinjection, a complete regrowth of hair in the previously hairless area, particularly evident in the case of 3D spheroids treated with the derivative, was observed. Additionally, histological and molecular analyses demonstrated an upregulation of markers associated with hair growth and a concurrent decrease in aging hallmarks, specifically in the 3D spheroids treated with the compound. In summary, our approach, which involves the treatment of Tri-SQ combined with a 3D spheroid system, exhibited a notably robust stimulating effect. This effect was observed in the induction of inductive properties in DP cells, leading to HF regeneration, and concurrently, it demonstrated an inhibitory effect on cellular and follicular aging.

The Roles of Exosomes in Regulating Hair Follicle Growth

Alopecia is considered a widespread yet troubling health issue, with limited treatment options. As membranous structures derived from cells carrying proteins, nucleic acids and lipids, exosomes functionally medicate intercellular communication and alter the responses of recipient cells, resulting in disease restraint or promotion. Exosomes have broad prospects in diagnosis and treatment of diseases. Studies using animal models and at the cellular level have clearly shown that exosomes from several types of cells, including dermal papilla cells and mesenchymal stem cells, have a notable capacity to promote hair growth, suggesting that exosomes may provide a new option to treat alopecia. Here, we present a thorough review of the most recent progress in the application of exosomes to hair growth.

An induced pluripotent stem cell-based approach for hair follicle development and regeneration

Because hair loss is a common concern for many individuals, potential regenerative therapies of hair follicles have been extensively researched. Induced pluripotent stem cells (iPSCs) are a promising avenue for hair follicle regeneration. This review explores current iPSC-based approaches and highlights their potential applications and challenges in hair restoration. The principles of iPSC technology, iPSC differentiation into hair follicle precursor cells, and potential clinical implications for hair follicle regeneration are also discussed. This overview of iPSCs and their applications aims to contribute to our understanding of their role in hair restoration and potential future therapeutic applications.

Promotion of hair growth by a conditioned medium from human umbilical cord mesenchymal stem cells cultivated in a 3D scaffold of gelatin sponge

BACKGROUND

This study aims to investigate the effects of a conditioned medium (CM) from human umbilical cord mesenchymal stem cells (HuMSCs) cultivated in gelatin sponge (GS-HuMSCs-CM) on hair growth in a mouse model.

METHODS

CM was collected from the HuMSCs cultivated in a monolayer or in a gelatin sponge. Vascular endothelial growth factor (VEGF), insulin-like growth factor-1 (IGF-1), keratinocyte growth factor (KGF), and hepatocyte growth factor (HGF) levels in CMs were measured by enzyme-linked immunosorbent assays (ELISAs). A hair loss model by a C57 BL/6J mouse was prepared. The effects of GS-HuMSCs-CM and HuMSCs on hair regrowth in mice were investigated by intradermal injection in the depilated back skin with normal saline (NS) as the control. The time for hair regrowth and full covering in depilated areas was observed, and the hair growth was evaluated histologically and by grossly measuring hair length and diameter.

RESULTS

Compared with monolayer cultured cells, the three-dimensional (3D) culture of HuMSCs in gelatin sponge drastically increased VEGF, IGF-1, KGF, and HGF production. GS-HuMSCs-CM and HuMSCs injection both promoted hair regeneration in mice, while GS-HuMSCs-CM presented more enhanced effects in hair length, hair diameter, and growth rate. GS-HuMSCs-CM significantly promoted angiogenesis in injected skin areas, which might also contribute to faster hair regrowth.

CONCLUSION

GS-HuMSCs-CM exerted significant effects on inducing hair growth and promoted skin angiogenesis in C57BL/6J mice.

Applications of Exosomal miRNAs from Mesenchymal Stem Cells as Skin Boosters

The skin is the outer layer of the human body, and it is crucial in defending against injuries and damage. The regenerative capacity of aging and damaged skin caused by exposure to external stimuli is significantly impaired. Currently, the rise in average life expectancy and the modern population's aesthetic standards have sparked a desire for stem-cell-based therapies that can address skin health conditions. In recent years, mesenchymal stem cells (MSCs) as therapeutic agents have provided a promising and effective alternative for managing skin regeneration and rejuvenation, attributing to their healing capacities that can be applied to damaged and aged skin. However, it has been established that the therapeutic effects of MSC may be primarily mediated by paracrine mechanisms, particularly the release of exosomes (Exos). Exosomes are nanoscale extracellular vesicles (EVs) that have lipid bilayer and membrane structures and can be naturally released by different types of cells. They influence the physiological and pathological processes of recipient cells by transferring a variety of bioactive molecules, including lipids, proteins, and nucleic acids such as messenger RNAs (mRNAs) and microRNAs (miRNAs) between cells, thus playing an important role in intercellular communication and activating signaling pathways in target cells. Among them, miRNAs, a type of endogenous regulatory non-coding RNA, are often incorporated into exosomes as important signaling molecules regulating protein biosynthesis. Emerging evidence suggests that exosomal miRNAs from MSC play a key role in skin regeneration and rejuvenation by targeting multiple genes and regulating various biological processes, such as participating in inflammatory responses, cell migration, proliferation, and apoptosis. In this review, we summarize the recent studies and observations on how MSC-derived exosomal miRNAs contribute to the regeneration and rejuvenation of skin tissue, with particular attention to the applications of bioengineering methods for manipulating the miRNA content of exosome cargo to improve their therapeutic potential. This review can provide new clues for the diagnosis and treatment of skin damage and aging, as well as assist investigators in exploring innovative therapeutic strategies for treating a multitude of skin problems with the aim of delaying skin aging, promoting skin regeneration, and maintaining healthy skin.

Fabricating Composite Cell Sheets for Wound Healing: Cell Sheets Based on the Communication Between BMSCs and HFSCs Facilitate Full-Thickness Cutaneous Wound Healing

BACKGROUND

Insufficient angiogenesis and the lack of skin appendages are critical challenges in cutaneous wound healing. Stem cell-fabricated cell sheets have become a promising strategy, but cell sheets constructed by a single cell type are inadequate to provide a comprehensive proregenerative microenvironment for wound tissue.

METHODS

Based on the communication between cells, in this study, bone marrow mesenchymal stem cells (BMSCs) and hair follicle stem cells (HFSCs) were cocultured to fabricate a composite cell sheet (H/M-CS) for the treatment of full-thickness skin wounds in mice.

RESULTS

Experiments confirmed that there is cell-cell communication between BMSCs and HFSCs, which enhances the cell proliferation and migration abilities of both cell types. Cell-cell talk also upregulates the gene expression of pro-angiogenic-related cytokines in BMSCs and pro-hair follicle-related cytokines in HFSCs, as well as causing changes in the properties of secreted extracellular matrix components.

CONCLUSIONS

Therefore, the composite cell sheet is more conducive for cutaneous wound healing and promoting the regeneration of blood vessels and hair follicles.

Biology and Therapeutic Properties of Mesenchymal Stem Cells in Leukemia

This comprehensive review delves into the multifaceted roles of mesenchymal stem cells (MSCs) in leukemia, focusing on their interactions within the bone marrow microenvironment and their impact on leukemia pathogenesis, progression, and treatment resistance. MSCs, characterized by their ability to differentiate into various cell types and modulate the immune system, are integral to the BM niche, influencing hematopoietic stem cell maintenance and functionality. This review extensively explores the intricate relationship between MSCs and leukemic cells in acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, and chronic lymphocytic leukemia. This review also addresses the potential clinical applications of MSCs in leukemia treatment. MSCs' role in hematopoietic stem cell transplantation, their antitumor effects, and strategies to disrupt chemo-resistance are discussed. Despite their therapeutic potential, the dual nature of MSCs in promoting and inhibiting tumor growth poses significant challenges. Further research is needed to understand MSCs' biological mechanisms in hematologic malignancies and develop targeted therapeutic strategies. This in-depth exploration of MSCs in leukemia provides crucial insights for advancing treatment modalities and improving patient outcomes in hematologic malignancies.

MiR-141-3p-Functionalized Exosomes Loaded in Dissolvable Microneedle Arrays for Hypertrophic Scar Treatment

Hypertrophic scar (HS) is a common fibroproliferative disease caused by abnormal wound healing after deep skin injury. However, the existing approaches have unsatisfactory therapeutic effects, which promote the exploration of newer and more effective strategies. MiRNA-modified functional exosomes delivered by dissolvable microneedle arrays (DMNAs) are expected to provide new hope for HS treatment. In this study, a miRNA, miR-141-3p, which is downregulated in skin scar tissues and in hypertrophic scar fibroblasts (HSFs), is identified. MiR-141-3p mimics inhibit the proliferation, migration, and myofibroblast transdifferentiation of HSFs in vitro by targeting TGF-β2 to suppress the TGF-β2/Smad pathway. Subsequently, the engineered exosomes encapsulating miR-141-3p (miR-141-3pOE -Exos) are isolated from adipose-derived mesenchymal stem cells transfected with Lv-miR-141-3p. MiR-141-3pOE -Exos show the same inhibitive effects as miR-141-3p mimics on the pathological behaviors of HSFs in vitro. The DMNAs for sustained release of miR-141-3pOE -Exos are further fabricated in vivo. MiR-141OE -Exos@DMNAs effectively decrease the thickness of HS and improve fibroblast distribution and collagen fiber arrangement, and downregulate the expression of α-SMA, COL-1, FN, TGF-β2, and p-Smad2/3 in the HS tissue. Overall, a promising, effective, and convenient exosome@DMNA-based miRNA delivery strategy for HS treatment is provided.

Exosomes for hair growth and regeneration

Exosomes are lipid bilayer vesicles, 30-200 nm in diameter, that are produced by cells and play essential roles in cell-cell communication. Exosomes have been studied in several medical fields including dermatology. Hair loss, a major disorder that affects people and sometimes causes mental stress, urgently requires more effective treatment. Because the growth and cycling of hair follicles are governed by interactions between hair follicle stem cells (HFSCs) and dermal papilla cells (DPCs), a better understanding of the mechanisms responsible for hair growth and cycling through exosomes may provide new insights into novel treatments for hair loss. In this review, we focused on the comprehensive knowledge and recent studies on exosomes in the field of hair development and regeneration. We classified exosomes of several cellular origins for the treatment of hair loss. Exosomes and their components, such as microRNAs, are promising drugs for effective hair loss treatment.

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.

Nanodrug Delivery Strategies to Signaling Pathways in Alopecia

Over 50% of the global population suffers from hair loss. The mixed results in the treatment of hair loss reveal the limitations of conventional commercial topical drugs. One the one hand, the definite pathogenesis of hair loss is still an enigma. On the other hand, targeted drug carriers ensure the drug therapeutic effect and low side effects. This review highlights the organization and overview of nine crucial signaling pathways associated with hair loss, as well as the development of nanobased topical delivery systems loading the clinical drugs, which will fuel emerging hair loss treatment strategies.

Nanotechnology-based techniques for hair follicle regeneration

The hair follicle (HF) is a multicellular complex structure of the skin that contains a reservoir of multipotent stem cells. Traditional hair repair methods such as drug therapies, hair transplantation, and stem cell therapy have limitations. Advances in nanotechnology offer new approaches for HF regeneration, including controlled drug release and HF-specific targeting. Until recently, embryogenesis was thought to be the only mechanism for forming hair follicles. However, in recent years, the phenomenon of wound-induced hair neogenesis (WIHN) or de novo HF regeneration has gained attention as it can occur under certain conditions in wound beds. This review covers HF-specific targeting strategies, with particular emphasis on currently used nanotechnology-based strategies for both hair loss-related diseases and HF regeneration. HF regeneration is discussed in several modalities: modulation of the hair cycle, stimulation of progenitor cells and signaling pathways, tissue engineering, WIHN, and gene therapy. The HF has been identified as an ideal target for nanotechnology-based strategies for hair regeneration. However, some regulatory challenges may delay the development of HF regeneration nanotechnology based-strategies, which will be lastly discussed.

Mesenchymal stromal cell-derived magnetic nanovesicles for enhanced skin retention and hair follicle growth

BACKGROUND AIMS

Extracellular vesicles and exosome-mimetic nanovesicles (NVs) derived from mesenchymal stromal cells (MSCs) have emerged as promising to promote hair growth. However, short local skin retention after subcutaneous administration hinders their clinical applications.

METHODS

In this study, we prepared magnetic nanovesicles (MNVs) from iron oxide nanoparticle-incorporated MSCs. MNVs contained more therapeutic growth factors than NVs derived from naive MSCs, and their localization and internalization were manipulated by external magnetic field.

RESULTS

Following the subcutaneous injection of MNVs into a mouse model of depilation-induced hair regeneration, the magnetic attraction increased their skin retention. Then, the cellular proliferation and β-catenin signaling in hair follicles (HF) were markedly enhanced by MNV injection and magnetic field application. Furthermore, an acceleration of HF growth was revealed by histological analysis.

CONCLUSIONS

The proposed strategy can enhance the therapeutic potential of MSC-derived NVs for hair regeneration and other dermatological diseases.

Bioactive Compound-Loaded Nanocarriers for Hair Growth Promotion: Current Status and Future Perspectives

Hair loss (alopecia) has a multitude of causes, and the problem is still poorly defined. For curing alopecia, therapies are available in both natural and synthetic forms; however, natural remedies are gaining popularity due to the multiple effects of complex phytoconstituents on the scalp with fewer side effects. Evidence-based hair growth promotion by some plants has been reported for both traditional and advanced treatment approaches. Nanoarchitectonics may have the ability to evolve in the field of hair- and scalp-altering products and treatments, giving new qualities to hair that can be an effective protective layer or a technique to recover lost hair. This review will provide insights into several plant and herbal formulations that have been reported for the prevention of hair loss and stimulation of new hair growth. This review also focuses on the molecular mechanisms of hair growth/loss, several isolated phytoconstituents with hair growth-promoting properties, patents, in vivo evaluation of hair growth-promoting activity, and recent nanoarchitectonic technologies that have been explored for hair growth.

Adipose-Derived Stem Cell Exosomes Antagonize the Inhibitory Effect of Dihydrotestosterone on Hair Follicle Growth by Activating Wnt/β-Catenin Pathway

The most prevalent type of alopecia is androgenetic alopecia (AGA), which has a high prevalence but no effective treatment. Elevated dihydrotestosterone (DHT) level in the balding area was usually thought to be critical in the pathophysiology of AGA. The canonical Wnt/β-catenin signaling pathway plays a key role in promoting hair follicle development and sustaining the hair follicle cycle. Adipose-derived stem cell exosomes (ADSC-Exos) are widely used in the field of regenerative medicine due to the advantages of being cell free and immune privileged. Still, few studies have reported the therapeutic effect on hair disorders. As a result, we sought to understand how ADSC-Exos affected hair growth and explore the possibility that ADSC-Exos could counteract the hair-growth-inhibiting effects of DHT. This research using human hair follicle organs, in vitro dermal papilla cells, and in vivo animal models showed that ADSC-Exos not only encouraged healthy hair growth but also counteracted the inhibitory effects of DHT on hair growth. Additionally, we discovered that ADSC-Exos increased Ser9 phosphorylated glycogen synthase kinase-3β levels and facilitated nuclear translocation of β-catenin, which may have been blocked by the specific Wnt/β-catenin signaling pathway inhibitor dickkopf-related protein 1. Our findings suggested that ADSC-Exos are essential for hair regeneration, which is anticipated to open up new therapeutic possibilities for clinical alopecia, particularly for the treatment of AGA.

Application of mesenchymal stem cells for anti-senescence and clinical challenges

Senescence is a hot topic nowadays, which shows the accumulation of senescent cells and inflammatory factors, leading to the occurrence of various senescence-related diseases. Although some methods have been identified to partly delay senescence, such as strengthening exercise, restricting diet, and some drugs, these only slow down the process of senescence and cannot fundamentally delay or even reverse senescence. Stem cell-based therapy is expected to be a potential effective way to alleviate or cure senescence-related disorders in the coming future. Mesenchymal stromal cells (MSCs) are the most widely used cell type in treating various diseases due to their potentials of self-replication and multidirectional differentiation, paracrine action, and immunoregulatory effects. Some biological characteristics of MSCs can be well targeted at the pathological features of aging. Therefore, MSC-based therapy is also a promising strategy to combat senescence-related diseases. Here we review the recent progresses of MSC-based therapies in the research of age-related diseases and the challenges in clinical application, proving further insight and reference for broad application prospects of MSCs in effectively combating senesce in the future.

Dissolving microneedles for alopecia treatment

Alopecia is a treatable benign disease, however, approximately 15-30% of women and 50% of men suffer from alopecia, which greatly affects patient's self-esteem and quality of life. Currently, commercial products for alopecia treatment include topical minoxidil solution, oral finasteride tablets and oral baricitinib tablets. However, the barrier of stratum corneum, systemic adverse effects and poor cure rate limit the application of commercial products. Therefore, researchers investigated the mechanism of alopecia, and developed new drugs that could target lactate dehydrogenase-related pathways, remove excessive reactive oxygen in hair follicles, and reduce the escape of hair follicle stem cells, thus injecting new strength into the treatment of alopecia. Moreover, starting from improving drug stratum corneum penetration and reducing side effects, researchers have developed hair loss treatment strategies based on dissolved microneedles (MNs), such as drug powders/microparticles, nanoparticles, biomimetic cell membranes, phototherapy and magnetically responsive soluble microneedles, which show exciting alopecia treatment effects. However, there are still some challenges in the practical application of the current alopecia treatment strategy with soluble microneedles, and further studies are needed to accelerate its clinical translation.

Various Three-Dimensional Culture Methods and Cell Types for Exosome Production

Cell-based therapies have been used as promising treatments for several untreatable diseases. However, cell-based therapies have side effects such as tumorigenesis and immune responses. To overcome these side effects, therapeutic effects of exosomes have been researched as replacements for cell-based therapies. In addition, exosomes reduced the risk that can be induced by cell-based therapies. Exosomes contain biomolecules such as proteins, lipids, and nucleic acids that play an essential role in cell-cell and cell-matrix interactions during biological processes. Since the introduction of exosomes, those have been proven perpetually as one of the most effective and therapeutic methods for incurable diseases. Much research has been conducted to enhance the properties of exosomes, including immune regulation, tissue repair, and regeneration. However, yield rate of exosomes is the critical obstacle that should be overcome for practical cell-free therapy. Three-dimensional (3D) culture methods are introduced as a breakthrough to get higher production yields of exosomes. For example, hanging drop and microwell were well known 3D culture methods and easy to use without invasiveness. However, these methods have limitation in mass production of exosomes. Therefore, a scaffold, spinner flask, and fiber bioreactor were introduced for mass production of exosomes isolated from various cell types. Furthermore, exosomes treatments derived from 3D cultured cells showed enhanced cell proliferation, angiogenesis, and immunosuppressive properties. This review provides therapeutic applications of exosomes using 3D culture methods.

Three-dimensional culture conditioned bone marrow MSC secretome accelerates wound healing in a burn injury mouse model

Mesenchymal stem cell (MSC)-based therapy has emerged as a promising regenerative therapeutic approach for wound healing. To determine the effects of cultured MSCs as a 2D monolayer (2D-MSCs) and 3D spheroids (3D-MSCs) on their secretomes, and to examine the effect of 3D-MSC secretomes on endothelial cells (ECs) and MSCs in a burn injury mouse model. MSCs were cultured as 2D monolayers (2D-MSCs) and 3D spheroids (3D-MSCs) and their cellular characteristics were evaluated by western blotting. 2D-MSC and 3D-MSC secretomes (condition medium: CM) were analyzed using an angiogenic array. The activation of ECs by 2D-MSC and 3D-MSC CMs was examined in cellular proliferation, migration, and tube formation assays. The wound healing effects of 2D-MSCs and 3D-MSCs were determined in vivo using a burn injury mouse model. 3D culture conditions altered the markers of components that regulate cell survival, cytoskeletal, adhesion, and proliferation. Interleukin-6 (IL-6), vascular endothelial growth factor A (VEGFA), IL-8, and chemokine (CXC motif) ligand 1 (CXCL1) were present at high levels in the CM of 3D-MSCs compared with 2D-MCs. 3D-MSC-CMs promoted the proliferation, migration, and tube formation of ECs. Furthermore, 3D-MSC treatment enhanced wound healing in a burn injury mouse model. 3D culture improves proangiogenic factors in the MSC secretome and 3D-MSCs represent a new cell-based treatment strategy for wound healing.

Androgenetic Alopecia: Therapy Update

Androgenetic alopecia (AGA), also known as male pattern hair loss (MPHL) or female pattern hair loss (FPHL), is the most common form of alopecia worldwide, and arises from an excessive response to androgens. AGA presents itself in a characteristic distribution unique to both sexes. Despite its prevalence, AGA can be quite challenging to treat. The condition is chronic in nature and stems from an interplay of genetic and environmental factors. There are only two US Food and Drug Administration (FDA)-approved drugs for the condition: topical minoxidil and oral finasteride. However, numerous non-FDA-approved treatments have been shown to be effective in treating AGA in various studies. Some of these treatments are relatively new and still to be explored, thus emphasizing the need for an updated review of the literature. In this comprehensive review, we discuss the evaluation of AGA and the mechanisms of action, costs, efficacies, and safety profiles of existing, alternative, and upcoming therapeutics for this widespread condition.

N6-Methyladenosine modification (m6A) of circRNA-ZNF638 contributes to the induced activation of SHF stem cells through miR-361-5p/Wnt5a axis in cashmere goats

OBJECTIVE

The objective of this study was to investigate the effects of N6-Methyladenosine modification-circRNA-zinc finger protein 638 (m6A-circRNA-ZNF638) on the induced activation of secondary hair follicle (SHF) stem cells with its potential mechanisms in cashmere goats.

METHODS

The m6A modification of ZNF638 was analyzed using methylation immunoprecipitation with real-time quantitative polymerase chain reaction technique in SHF stem cells. The effects of circRNA-ZNF638 on the induced activation of SHF stem cells in m6A dependence were evaluated through the overexpression of circRNA-ZNF638/its m6Adeficient mutants in circRNA-ZNF638 knockdown SHF stem cells. The competitive binding of miR-361-5p to circRNA-ZNF638/Wnt5a 3'- untranslated region was analyzed through Dual-luciferase reporter assay.

RESULTS

The m6A-circRNA-ZNF638 had significantly higher transcription at anagen SHF bulge of cashmere goats compared with that at telogen, as well as it positively regulated the induced activation of SHF-stem cells in cashmere goats. Mechanismly, m6A-circRNA-ZNF638 sponged miR-361-5p to heighten the transcriptional expression of Wnt5a gene in SHFstem cells. We further demonstrated that the internal m6A modification within circRNAZNF638 is required for mediating the miR-361-5p/Wnt5a pathway to regulate the induced activation of SHF stem cells through an introducing of m6A-deficient mutant of circRNAZNF638.

CONCLUSION

The circRNA-ZNF638 contributes the proper induced activation of SHF-stem cells in cashmere goats in m6A-dependent manner through miR-361-5p/Wnt5a axis.

Treatment of persistent chemotherapy-induced hair loss (Alopecia) with human mesenchymal stromal cells extracellular enriched vesicles: A case report

Introduction

Cancer is among the leading causes of death worldwide and affects a considerable number of individuals. Chemotherapy is one the most common treatment for this condition and hair loss is among one of the most prevalent side effects. In this study, we report successful treatment of a patient suffering from persistent chemotherapy-induced alopecia (PCIA) with extracellular enriched vesicles (EVs) derived from human placental mesenchymal stromal cells (MSCs).

Case presentation

The patient was a 36-year-old woman with a history of invasive ductal carcinoma, underwent six courses of chemotherapy with paclitaxel and adriamycin. Following this treatment and for almost 18 months, she, unfortunately, had no regrowth of hair except some light vellus hairs on the scalp. She then received MSC-derived EVs with scalp injection (subcutaneous) every 4 weeks for 3 continuous months at which point she presented complete regrowth of terminal hair on her scalp.

Conclusion

This report demonstrates that MSC-derived EVs could be a possible treatment for permanent chemotherapy-induced alopecia; however, further studies and trials are necessary.

Exosomes: the latest in regenerative aesthetics

Regenerative aesthetics is a burgeoning field for skin rejuvenation and skin health restoration. Exosomes, or extracellular vesicles, represent a new and minimally invasive addition to the regenerative aesthetic toolbox. These nano-sized vesicles contain bioactive cargo with crucial roles in intercellular communication. Exosome technology, while still in its infancy, is now leveraged in regenerative aesthetic medicine due to its multifaceted role in targeting root causes of skin aging and improving overall tissue homeostasis. The main considerations for practice utilization include variation in exosome purification, isolation, storage, scalability and reproducibility. This review aims at highlighting the current and emerging landscape of exosomes in aesthetic medicine including skin rejuvenation and hair restoration.

A Novel Hair Restoration Technology Counteracts Androgenic Hair Loss and Promotes Hair Growth in A Blinded Clinical Trial

Androgenic alopecia (AGA) is a genetically predetermined condition that occurs as a result of stepwise miniaturization of the dermal papilla. During this process, the hair follicle suffers from increasing malnutrition and eventually dies, causing progressive hair loss. We recently highlighted that HIF-1α modulation may counteract hair loss. Here, we aim to demonstrate the positive influence of Tomorrowlabs HIF strengthening factor [HSF] hair restoration technology on hair biology in a monocentric blinded clinical trial over a total period of 9 months. A trial with 20 subjects (4 female and 16 male) and once-daily application of [HSF] hair restoration technology to the scalp was conducted. To assess the tolerability and efficacy of [HSF], testing included dermatological assessment, determination of hair loss by counting after combing, macro images of the head and TrichoScan evaluation of hair density as well as the proportion of anagen hair versus telogen hair. The clinical data show Tomorrowlabs [HSF] hair restoration to be safe and effective to counteract AGA. The use of Tomorrowlabs [HSF] hair restoration resulted in improvements in the clinical parameters of hair quality such as thickness (+7.2%), hair density (+14.3%) and shine and elasticity (+20.3%) during the test period. The effectiveness of the test product was further determined by a significant reduction in hair loss of an average of 66.8% in treatment-responsive subjects after 6 months and an increase in hair growth reaching up to 32.5%, with an average percentage change of 8.4% in all participants and 10.8% in the responsive patients (85% of the study cohort) after 9 months on TrichoScan evaluation. The hair growth cycle was harmonized with the result of an average anagen hair percentage increase of +8.0% and telogen hair percentage reduction of -14.0% shown in the test area. Applicable for both sexes in an alcohol-free formulation, beneficial to scalp health and free of complications or side effects, this novel product provides objectively measurable results counteracting hair loss paired with an improved look and feel of the hair.

Preparation of therapy-grade extracellular vesicles from adipose tissue to promote diabetic wound healing

Background: Treatment of diabetic wounds is a major challenge in clinical practice. Extracellular vesicles (EVs) from adipose-derived stem cells have shown effectiveness in diabetic wound models. However, obtaining ADSC-EVs requires culturing vast numbers of cells, which is hampered by the need for expensive equipment and reagents, extended time cost, and complicated procedures before commercialization. Therefore, methods to extract EVs from discarded tissue need to be developed, for immediate application during surgery. For this reason, mechanical, collagenase-digestive, and constant in-vitro-collective methods were designed and compared for preparing therapy-grade EVs directly from adipose tissue. Methods: Characteristics and quantities of EVs were detected by transmission electron microscopy, nanoparticle tracking analysis, and Western blotting firstly. To investigate the biological effects of EVs on diabetic wound healing, angiogenesis, proliferation, migration, and inflammation-regulation assays were then evaluated in vitro, along with a diabetic wound healing mouse model in vivo. To further explore the potential therapeutic mechanism of EVs, miRNA expression profile of EVs were also identified and analyzed. Results: The adipose tissue derived EVs (AT-EVs) were showed to qualify ISEV identification by nanoparticle tracking analysis and Western blotting and the AT-EVs yield from three methods was equal. EVs also showed promoting effects on biological processes related to diabetic wound healing, which depend on fibroblasts, keratinocytes, endothelial cells, and macrophages both in vitro and in vivo. We also observed enrichment of overlapping or unique miRNAs originate from different types of AT-EVs associated with diabetic wound healing for further investigation. Conclusion: After comparative analyses, a mechanical method was proposed for preparing immediate clinical applicable EVs from adipose tissue that would result in reduced preparation time and lower cost, which could have promising application potential in treating diabetic wounds.

Apoptotic extracellular vesicles are metabolized regulators nurturing the skin and hair

Over 300 billion of cells die every day in the human body, producing a large number of endogenous apoptotic extracellular vesicles (apoEVs). Also, allogenic stem cell transplantation, a commonly used therapeutic approach in current clinical practice, generates exogenous apoEVs. It is well known that phagocytic cells engulf and digest apoEVs to maintain the body's homeostasis. In this study, we show that a fraction of exogenous apoEVs is metabolized in the integumentary skin and hair follicles. Mechanistically, apoEVs activate the Wnt/β-catenin pathway to facilitate their metabolism in a wave-like pattern. The migration of apoEVs is enhanced by treadmill exercise and inhibited by tail suspension, which is associated with the mechanical force-regulated expression of DKK1 in circulation. Furthermore, we show that exogenous apoEVs promote wound healing and hair growth via activation of Wnt/β-catenin pathway in skin and hair follicle mesenchymal stem cells. This study reveals a previously unrecognized metabolic pathway of apoEVs and opens a new avenue for exploring apoEV-based therapy for skin and hair disorders.

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Exogenous infused apoEVs are partly metabolized from the integumentary skin and hair follicles.

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ApoEVs activate Wnt/β-catenin pathway to facilitate their elimination in a wave-like pattern.

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Exercise can enhance apoEV metabolism through Wnt/β-catenin pathway.

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MSC-derived apoEVs promote wound healing and hair growth.

Exosomes based advancements for application in medical aesthetics

Beauty is an eternal pursuit of all people. Wound repair, anti-aging, inhibiting hyperpigmentation and hair loss are the main demands for medical aesthetics. At present, the repair and remodeling of human body shape and function in medical aesthetics are often achieved by injection of antioxidants, hyaluronic acid and botulinum toxin, stem cell therapy. However, there are some challenges, such as difficulty controlling the injection dose, abnormal local contour, increased foreign body sensation, and the risk of tumor occurrence and deformity induced by stem cell therapy. Exosomes are tiny vesicles secreted by cells, which are rich in proteins, nucleic acids and other bioactive molecules. They have the characteristics of low immunogenicity and strong tissue penetration, making them ideal for applications in medical aesthetics. However, their low yield, strong heterogeneity, and long-term preservation still hinder their application in medical aesthetics. In this review, we summarize the mechanism of action, administration methods, engineered production and preservation technologies for exosomes in medical aesthetics in recent years to further promote their research and industrialization in the field of medical aesthetics.

Engineered Nanovesicles from Fibroblasts Modulate Dermal Papillae Cells In Vitro and Promote Human Hair Follicle Growth Ex Vivo

Alopecia is a common medical condition affecting both sexes. Dermal papilla (DP) cells are the primary source of hair regeneration in alopecia patients. Therapeutic applications of extracellular vesicles (EVs) are restricted by low yields, high costs, and their time-consuming collection process. Thus, engineered nanovesicles (eNVs) have emerged as suitable therapeutic biomaterials in translational medicine. We isolated eNVs by the serial extrusion of fibroblasts (FBs) using polycarbonate membrane filters and serial and ultracentrifugation. We studied the internalization, proliferation, and migration of human DP cells in the presence and absence of FB-eNVs. The therapeutic potential of FB-eNVs was studied on ex vivo organ cultures of human hair follicles (HFs) from three human participants. FB-eNVs (2.5, 5, 7.5, and 10 µg/mL) significantly enhanced DP cell proliferation, with the maximum effect observed at 7.5 µg/mL. FB-eNVs (5 and 10 µg/mL) significantly enhanced the migration of DP cells at 36 h. Western blotting results suggested that FB-eNVs contain vascular endothelial growth factor (VEGF)-a. FB-eNV treatment increased the levels of PCNA, pAKT, pERK, and VEGF-receptor-2 (VEGFR2) in DP cells. Moreover, FB-eNVs increased the human HF shaft size in a short duration ex vivo. Altogether, FB-eNVs are promising therapeutic candidates for alopecia.

Construction of transcriptome atlas of white yak hair follicle during anagen and catagen using single-cell RNA sequencing

BACKGROUND

As the direct organ of villus, hair follicles have obvious seasonal cycles. The hair follicle cycle is orchestrated by multiple cell types that together direct cell renewal and differentiation. But the regulation property of hair follicle cells from anagen to catagen in yak is still unknown.

RESULTS

In this study, single-cell RNA sequencing was performed on 24,124 single cells of the scapular skin from white yak. Based on tSNE cluster analysis, the cell types of IFE-DC, epidermal cell lines, fibroblasts, keratinocytes, IRS, DS, INFU, and other cells in yak hair follicles during anagen and catagen were successfully identified, and the gene expression profiles were described. The GO enrichment analysis indicated the different cells characteristic genes to be mainly enriched in the epidermal development, epithelial cell differentiation and wound healing pathways. The pseudotime trajectory analysis described the differentiation trajectory of the epidermal lineage and dermal lineage of the hair follicle during anagen and catagen. Moreover, the dynamic changes of the genes like LHX2, KRT25, and KRT71 were found to be highly expressed in HS and IRS, but not in the IFE-DC, INFU, and keratinocyte during differentiation.

CONCLUSIONS

Our results analyzed the time-varying process of gene expression in the dermal cell lineage and epidermal cell lineage of hair follicles during anagen and catagen during fate differentiation was expounded at the single cell level, revealing the law of fate specialization of different types of cells. In addition, based on the enrichment analysis, the transcriptional regulatory factors involved in the different cell fates were also revealed. These results will help to enhance our understanding of yak hair follicle cycle and promote the development and utilization of yak villus.

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.

Interleukin-4 Receptor Targeting Peptide Decorated Extracellular Vesicles as a Platform for In Vivo Drug Delivery to Thyroid Cancer

Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) have been demonstrated to deliver therapeutic drugs in preclinical studies. However, their use is limited, as they lack the ability to specifically deliver drugs to tumor tissues in vivo. In the present study, we propose the use of a targeting peptide, IL-4R-binding peptide (IL4RPep-1), to specifically deliver intravenously (i.v.) infused EVs to thyroid tumors. In vivo, a xenograft tumor model was treated with either the control peptide (NSSSVDK) or IL4RPep-1-Flamma; mice were fluorescently imaged (FLI) using an in vivo imaging system at 0–3 h post-treatment. EVs (labeled with DiD dye) were conjugated with IL4RPep-1 through a DOPE-NHS linker and administered to mice intravenously. FLI was performed 0–24 h post-injection, and the animals were sacrificed for further experiments. The morphology and size of EVs, the presence of EV markers such as CD63 and ALIX, and the absence of the markers GM130 and Cyto-C were confirmed. In vivo, FLI indicated an accumulation of i.v. injected IL4RPep-1-Flamma at the tumor site 90 min post-injection. No accumulation of NSSSVDK-Flamma was detected. In vivo, IL4RPep-1-EVs targeted the Cal-62 tumor 2 h post-injection. NSSSVDK-EVs were not even detected in the tumor 24 h post-injection. The quantification of FLI showed a significant accumulation of MSC-EVs in the tumor 2 h, 3 h, and 24 h post-injection. Furthermore, ex vivo imaging and an IF analysis confirmed the in vivo findings. Our results demonstrate the use of the IL4RPep-1 peptide as a targeting moiety of EVs for IL-4R-expressing anaplastic thyroid tumors.

Activation of cAMP Signaling in Response to α-Phellandrene Promotes Vascular Endothelial Growth Factor Levels and Proliferation in Human Dermal Papilla Cells

Dermal papilla cells (DPCs) are growth factor reservoirs that are specialized for hair morphogenesis and regeneration. Due to their essential role in hair growth, DPCs are commonly used as an in vitro model to investigate the effects of hair growth-regulating compounds and their molecular mechanisms of action. Cyclic adenosine monophosphate (cAMP), an intracellular second messenger, is currently employed as a growth-promoting target molecule. In a pilot test, we found that α-phellandrene, a naturally occurring phytochemical, increased cAMP levels in DPCs. Therefore, we sought to determine whether α-phellandrene increases growth factors and proliferation in human DPCs and to identify the underlying mechanisms. We demonstrated that α-phellandrene promotes cell proliferation concentration-dependently. In addition, it increases the cAMP downstream effectors, such as protein kinase A catalytic subunit (PKA Cα) and phosphorylated cAMP-responsive element-binding protein (CREB). Also, among the CREB-dependent growth factor candidates, we identified that α-phellandrene selectively upregulated vascular endothelial growth factor (VEGF) mRNA expression in DPCs. Notably, the beneficial effects of α-phellandrene were nullified by a cAMP inhibitor. This study demonstrated the cAMP-mediated growth effects in DPCs and the therapeutic potential of α-phellandrene for preventing hair loss.

Application of Cell-Derived Extracellular Vesicles and Engineered Nanovesicles for Hair Growth: From Mechanisms to Therapeutics

Hair loss is one of the most common disorders that affect both male and female patients. Cell-derived nanovesicles (CDVs) are natural extracellular vesicles and engineered nanovesicles that can carry various biologicals materials such as proteins, lipids, mRNA, miRNA, and DNA. These vesicles can communicate with local or distant cells and are capable of delivering endogenous materials and exogenous drugs for regenerative therapies. Recent studies revealed that CDVs can serve as new treatment strategies for hair growth. Herein, we review current knowledge on the role of CDVs in applications to hair growth. The in-depth understanding of the mechanisms by which CDVs enable therapeutic effects for hair growth may accelerate successful clinical translation of these vesicles for treating hair loss.

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 microscopy, 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.

3D Spheroid Human Dermal Papilla Cell as an Effective Model for the Screening of Hair Growth Promoting Compounds: Examples of Minoxidil and 3,4,5-Tri-O-caffeoylquinic acid (TCQA)

Dermal papilla cells (DPCs) are an important element of the hair follicle (HF) niche, widely used as an in vitro model to study hair growth-related research. These cells are usually grown in 2D culture, but this system did not show efficient therapeutic effects on HF regeneration and growth, and key differences were observed between cell activity in vitro and in vivo. Recent studies have showed that DPCs grown in 3D hanging spheroids are more morphologically akin to an intact DP microenvironment. In this current study, global gene molecular analysis showed that the 3D model highly affected cell adhesion molecules and hair growth-related pathways. Furthermore, we compared the expression of signalling molecules and metabolism-associated proteins of DPCs treated with minoxidil (an FDA-approved drug for hair loss treatment) and 3,4,5-tri-O-caffeoylquinic acid (TCQA) (recently found to induce hair growth in vitro and in vivo) in 3D spheroid hanging drops and a 2D monolayer using DNA microarray analysis. Further validations by determining the gene and protein expressions of key signature molecules showed the suitability of this 3D system for enhancing the DPC activity of the hair growth-promoting agents minoxidil and TCQA.

Identification of Angiogenic Cargoes in Human Fibroblasts-Derived Extracellular Vesicles and Induction of Wound Healing

A complete redevelopment of the skin remains a challenge in the management of acute and chronic wounds. Recently, the application of extracellular vesicles (EVs) for soft tissue wound healing has received much attention. As fibroblasts are fundamental cells for soft tissues and skin, we investigate the proangiogenic factors in human normal fibroblast-derived EVs (hNF-EVs) and their effects on wound healing. Normal fibroblasts were isolated from human skin tissues and characterized by immunofluorescence (IF) and Western blotting (WB). hNF-EVs were isolated by ultracentrifugation and characterized using transmission electron microscopy and WB. The proangiogenic cargos in hNF-EVs were identified by a TaqMan assay and a protein array. Other in vitro assays, including internalization assays, cell counting kit-8 analysis, scratch wound assays, WBs, and tube formation assays were conducted to assess the effects of hNF-EVs on fibroblasts and endothelial cells. A novel scaffold-free noninvasive delivery of hNF-EVs with or without fibrin glue was applied onto full-thickness skin wounds in mice. The wound healing therapeutical effect of hNF-EVs was assessed by calculating the rate of wound closure and through histological analysis. Isolated hNF was confirmed by verifying the expression of the fibroblast markers vimentin, αSMA, Hsp70, and S100A4. Isolated hNF-EVs showed intact EVs with round morphology, enriched in CD81 and CD63, and devoid of the cell markers GM130, Calnexin, and Cytochrome C. Our TaqMan assay showed that hNF-EVs were enriched in miR130a and miR210, and protein arrays showed enriched levels of the proangiogenic proteins’ vascular endothelial growth factor (VEGF)-D and CXCL8. Next, we found that the internalization of hNF-EVs into hNF increased the proliferation and migration of hNF, in addition to increasing the expression of bFGF, MMP2, and αSMA. The internalization of hNF-EVs into the endothelial cells increased their proliferation and tube formation. A scaffold-free noninvasive delivery of hNF-EVs with or without fibrin glue accelerated the wound healing rate in full-thickness skin wounds in mice, and the treatments increased the cellular density, deposition, and maturation of collagens in the wounds. Moreover, the scaffold-free noninvasive delivery of hNF-EVs with or without fibrin glue increased the VEGF and CD31 expression in the wounds, indicating that hNF-EVs have an angiogenic ability to achieve complete skin regeneration. These findings open up for new treatment strategies to be developed for wound healing. Further, we offer a new approach to the efficient, scaffold-free noninvasive delivery of hNF-EVs to wounds.

Clinical Use of Extracellular Vesicles in the Management of Male and Female Pattern Hair Loss: A Preliminary Retrospective IRB Safety and Efficacy Study

Background

Pattern hair loss is a common disorder in female and male subjects that may benefit from the use of cell-free XoFlo (Direct Biologics, LLC, Austin, TX) therapy.

Objectives

To assess the safety, efficacy and satisfaction of a single extracellular vesicle (EV) treatment over 6 months.

Methods

A retrospective open-label study among 22 female and 9 male subjects who demonstrated early stages of alopecia or were in remission from prior medical and surgical treatments. The amount of undiluted or diluted volumes of EV solution used was determined by extent and degree of alopecia. Global photography, SGAIS and IGAIS questionnaires, and trichoscan measurements were compared at baseline and six months in three response categories.

Results

Frequent growth responses were observed: older aged females and younger aged males, shorter history of alopecia; earlier stages of hair loss; larger and undiluted volumes of XoFlo; prior positive responses to medical and surgical treatments; and absence or control of disease factors affecting hair. The benefit of micro-needling to therapy was indeterminate. Global photography, trichoscan for density, follicle diameter, terminal: vellus ratio, and SGAIS/IGAIS satisfaction questionnaires at baseline and six months were useful in assessing clinical efficacy. No significant adverse reactions were observed.

Conclusions

Intradermal injections with varying doses of EVs were safe and effective among indicated alopecic female and male subjects. Findings suggest that the presence of positive factors, absence of conditions known to negatively affect hair growth, and administration of larger volumes of XoFlo may have a significant influence on the use of this new cell-free therapy. FDA-approved biologic, multi-centered IRB/ Investigational New Drug (IND) trials are clearly required to determine its future in the management of hair loss.

Update on Exosomes in Aesthetics

BACKGROUND

In dermatology, exosomes have been leveraged given their roles in wound healing, cell migration, extracellular matrix reconstruction, and angiogenesis.

OBJECTIVE

The purpose of this article is to review the literature investigating the use of exosomes in skin rejuvenation and hair regeneration.

MATERIALS AND METHODS

The PubMed database was searched for studies published through October 2021.

RESULTS

Early preclinical studies in aesthetics have demonstrated promising effects of exosomes on skin rejuvenation and hair growth in in vitro and murine models. Despite this, only 1 clinical study has been published to date, and there are no FDA-approved products on the market.

CONCLUSION

Variation in purification techniques and practical issues surrounding isolation, storage, scalability, and reproducibility of an exosome product represent ongoing hindrances to the movement of exosomes into the clinical sphere.

The effects of centipedegrass extract on hair growth via promotion of anagen inductive activity

To investigate the CGE on hair growth and to explore the mechanism that is involved in the acceleration of anagen induction, we investigated the effects of CGE studied on cell proliferation and molecular mechanism in human hair dermal papilla cells (hDPCs) and keratinocytes (HaCaT cells). Additionally, hair growth evaluation was carried out following topical treatment of the dorsal skin of telogen C57BL/6 mice with CGE for 14 days. As result, CGE increased cell viability and ALP activity in hDPCs. Moreover, CGE increased the expression of catenin beta 1 (CTNNB1), ALP, sex-determining region Y-box 2 (SOX2), insulin-like growth factor 1 (IGF1), and vascular endothelial growth factor A (VEGFA) genes in hDPCs. CGE increased the expression of proteins such as ALP, β-catenin, and phosphorylation of glycogen synthase kinase 3β (pGSK3β), and protein kinase B (pAKT) in hDPCs. Furthermore, CGE induced the proliferation of HaCaT cells and up-regulated AKT-ERK-GSKβ-β-catenin signaling in HaCaT cells. Additionally, the anagen induction effects of CGE were confirmed on the telogen-anagen transition mice model. these findings demonstrated that CGE promoted the entering the growth phase of hair follicle via activation of β-catenin signaling pathways in vivo. Thus, this study suggests that CGE might be a potential therapeutic reagent for hair growth.

Potential of Colostrum-Derived Exosomes for Promoting Hair Regeneration Through the Transition From Telogen to Anagen Phase

Human hair dermal papillary (DP) cells comprising mesenchymal stem cells in hair follicles contribute critically to hair growth and cycle regulation. The transition of hair follicles from telogen to anagen phase is the key to regulating hair growth, which relies heavily on the activation of DP cells. In this paper, we suggested exosomes derived from bovine colostrum (milk exosomes, Milk-exo) as a new effective non-surgical therapy for hair loss. Results showed that Milk-exo promoted the proliferation of hair DP cells and rescued dihydrotestosterone (DHT, androgen hormones)-induced arrest of follicle development. Milk-exo also induced dorsal hair re-growth in mice at the level comparable to minoxidil treatment, without associated adverse effects such as skin rashes. Our data demonstrated that Milk-exo accelerated the hair cycle transition from telogen to anagen phase by activating the Wnt/β-catenin pathway. Interestingly, Milk-exo has been found to stably retain its original properties and efficacy for hair regeneration after freeze-drying and resuspension, which is considered critical to use it as a raw material applied in different types of alopecia medicines and treatments. Overall, this study highlights a great potential of an exosome from colostrum as a therapeutic modality for hair loss.

Advancing Regenerative Cellular Therapies in Non-Scarring Alopecia

Alopecia or baldness is a common diagnosis in clinical practice. Alopecia can be scarring or non-scarring, diffuse or patchy. The most prevalent type of alopecia is non-scarring alopecia, with the majority of cases being androgenetic alopecia (AGA) or alopecia areata (AA). AGA is traditionally treated with minoxidil and finasteride, while AA is treated with immune modulators; however, both treatments have significant downsides. These drawbacks compel us to explore regenerative therapies that are relatively devoid of adverse effects. A thorough literature review was conducted to explore the existing proven and experimental regenerative treatment modalities in non-scarring alopecia. Multiple treatment options compelled us to classify them into growth factor-rich and stem cell-rich. The growth factor-rich group included platelet-rich plasma, stem cell-conditioned medium, exosomes and placental extract whereas adult stem cells (adipose-derived stem cell-nano fat and stromal vascular fraction; bone marrow stem cell and hair follicle stem cells) and perinatal stem cells (umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs), Wharton jelly-derived MSCs (WJ-MSCs), amniotic fluid-derived MSCs (AF-MSCs), and placental MSCs) were grouped into the stem cell-rich group. Because of its regenerative and proliferative capabilities, MSC lies at the heart of regenerative cellular treatment for hair restoration. A literature review revealed that both adult and perinatal MSCs are successful as a mesotherapy for hair regrowth. However, there is a lack of standardization in terms of preparation, dose, and route of administration. To better understand the source and mode of action of regenerative cellular therapies in hair restoration, we have proposed the "À La Mode Classification". In addition, available evidence-based cellular treatments for hair regrowth have been thoroughly described.

Research update of adipose tissue-based therapies in regenerative dermatology

Mesenchymal stromal/stem cells (MSCs) have a spontaneous propensity to support tissue homeostasis and regeneration. Among the several sources of MSCs, adipose-derived tissue stem cells (ADSCs) have received major interest due to the higher mesenchymal stem cells concentration, ease, and safety of access. However, since a significant part of the natural capacity of ADSCs to repair damaged tissue is ascribable to their secretory activity that combines mitogenic factors, cytokines, chemokines, lipids, and extracellular matrix components, several studies focused on cell-free strategies. Furthermore, adipose cell-free derivatives are becoming more attractive especially for non-volumizing purposes, such as most dermatological conditions. However, when keratinocytes, fibroblasts, melanocytes, adipocytes, and hair follicle cells might not be locally sourced, graft of materials containing concentrated ADSCs is preferred. The usage of extracellular elements of adipose tissue aims to promote a self-autonomous regenerative microenvironment in the receiving area restoring physiological homeostasis. Hence, ADSCs or their paracrine activity are currently being studied in several dermatological settings including wound healing, skin fibrosis, burn, and aging.The present work analyzing both preclinical and clinical experiences gives an overview of the efficacy of adipose tissue-derivatives like autologous fat, the stromal vascular fraction (SVF), purified ADSCs, secretome and extracellular matrix graft in the field of regenerative medicine for the skin.

Stimulatory Effects of Extracellular Vesicles Derived from Leuconostoc holzapfelii That Exists in Human Scalp on Hair Growth in Human Follicle Dermal Papilla Cells

Human hair follicle dermal papilla cells (HFDPCs) located in hair follicles (HFs) play a pivotal role in hair follicle morphogenesis, hair cycling, and hair growth. Over the past few decades, probiotic bacteria (PB) have been reported to have beneficial effects such as improved skin health, anti-obesity, and immuno-modulation for conditions including atopic dermatitis and inflammatory bowel disease (IBD). PB can secrete 50~150 nm sized extracellular vesicles (EVs) containing microbial DNA, miRNA, proteins, lipids, and cell wall components. These EVs can regulate communication between bacteria or between bacteria and their host. Although numerous biological effects of PB-EVs have been reported, the physiological roles of Leuconostoc holzapfelii (hs-Lh), which is isolated from human scalp tissue, and the extracellular vesicles derived from them (hs-LhEVs) are largely unknown. Herein, we investigated the effects of hs-LhEVs on hair growth in HFDPCs. We show that hs-LhEVs increase cell proliferation, migration, and regulate the cell cycle. Furthermore, hs-LhEVs were found to modulate the mRNA expression of hair-growth-related genes in vitro. These data demonstrate that hs-LhEVs can reduce apoptosis by modulating the cell cycle and promote hair growth by regulation via the Wnt/β-catenin signal transduction pathway.

Exosomes Secreted from Adipose-Derived Stem Cells Are a Potential Treatment Agent for Immune-Mediated Alopecia

Background

Alopecia has become an exceedingly prevalent dermatological disorder. Etiologically, infection (bacterial and fungal infection), inflammation, and immune dysregulation are the main causes of immune-mediated hair loss. Treating hair loss has remained challenging as the available therapies are limited. Exosomes from adipose-derived stem cells (ADSC-Exos) have been used for treating neurodegenerative diseases and autoimmune diseases and in wound-healing treatments. However, the function and mechanism of ADSC-Exos in alopecia treatment remain unclear. This study is aimed at investigating the effects of ADSC-Exos on hair growth in vitro and in vivo for potentially treating immune-mediated alopecia and further exploring the underlying mechanism.

Methods

Cell proliferation, migration, and apoptosis of dermal papilla cells (DPCs) that were treated with ADSC-Exos were detected using the cell counting kit-8 (CCK-8) assay, scratch wound-healing assay, and flow cytometry assay, respectively. A C57BL/6 hair-depilated mouse model was established in vivo; then, ADSC-Exos were subcutaneously injected alone or in combined with minoxidil. The effects of ADSC-Exos on hair growth, pathological changes, and the related mechanism were investigated by HE staining, quantitative real‐time PCR (qRT-PCR), western blotting, and RNA sequencing (RNA-seq).

Results

ADSC-Exos significantly promoted DPC proliferation and migration while also reducing apoptosis. In addition, compared with the control group, ADSC-Exos-treated mice had better hair growth, more hair follicles (HFs) and thicker dermis. RNA-seq revealed that the miR-22 and TNF-α signaling pathways were markedly downregulated in DPCs after ADSC-Exos treatment. In addition, according to qRT-PCR and western blotting results, the Wnt/β-catenin signaling pathway was activated in the skin of ADSC-Exos-treated mice.

Conclusion

ADSC-Exos therapy positively affected the promotion of hair regrowth by regulating miR-22, the Wnt/β-catenin signaling pathway, and the TNF-α signaling pathway, implying that ADSC-Exos could be a promising cell-free therapeutic strategy for immune-mediated alopecia.