Growth factors in hair organ development and the hair growth cycle

"Effectiveness of minimally invasive injectable modalities in the management of androgenetic alopecia among adults-A systematic review"

BACKGROUND

Androgenetic alopecia is the most common cause of hair loss that affects over 50% of the world population. It is a condition that is multifactorial in origin, with no specific causative factor, making treatment an enervating experience for the patient as well as the doctor. In recent times, a number of modalities have been introduced for the treatment of alopecia. However, the evidence supporting them is unstructured and sparse. Therefore, this article aims to explore the current trends in minimally invasive treatments for the management of androgenetic alopecia.

METHODS

An in-depth literature search on injectables used in the treatment of alopecia in PubMed/MEDLINE, Embase, PsycINFO, TRIP Cochrane Library, and Cochrane Skin databases between January 2000 and May 2023 was performed. The studies included were randomized controlled trials, non-randomized trials, quasi trials, single arm interventions, and cohort studies.

RESULTS

Sixteen of the 1071 studies that were found during the original search were accepted in accordance with the inclusion criteria. Twelve studies assessed the effectiveness of the injectable group by comparing it to a control group consisting of saline, distilled water, and topical minoxidil. In the treatment of alopecia, dutasteride and injectable growth factor formulations achieved clinically significant results.

CONCLUSION

The usage of injectables and topical medicines to treat hair loss has increased in the recent years. Overall results from clinical investigations, pilot studies, and trials looking at the efficacy and safety of these growth factors in the AGA show satisfactory efficacy.

CRABP1 Enhances the Proliferation of the Dermal Papilla Cells of Hu Sheep through the Wnt/β-catenin Pathway

BACKGROUND

The homologous proteins identified as cellular retinoic acid-binding proteins I and II (CRABP-I and CRABP-II) belong to a subset of intracellular proteins characterized by their robust affinity for retinoic acid, which plays an indispensable role in the development of hair follicle, including differentiation, proliferation, and apoptosis in keratinocytes. Previous research on Hu sheep hair follicles revealed the specific expression CRABP1 in dermal papilla cells (DPCs), suggesting that CRABP1 has a potential role in regulating the DPC population. Therefore, the main purpose of this study is to expose the performance of the CRABP1 genes in the development and proliferation of DPCs.

METHODS

Initially, overexpression and inhibition of CRABP1 in the DPCs were conducted through overexpression vector and siRNA. CCK-8, EDU, and RT-PCR cell cycle assays and immunostaining were performed to evaluate the proliferation and cell cycle of dermal papilla cells (DPCs). Although, the influence of CRABP1 upon β-catenin in dermal papilla cells (DPCs) was found using immunofluorescence labeling. Finally, RT-PCR was conducted to assess the impact of CRABP1 on the expression levels of CTNNB1, TCF4, and LEF1 in DPCs involved in the Wnt/β-catenin signaling pathway.

RESULTS

The results showed that CRABP1 overexpression promotes the growth rates of DPCs and significantly enhances the proportion of S-phase cells compared with the control group (p < 0.05). The results were the opposite when CRABP1 was a knockdown. In contrast, there was a significant decline in the mRNA expression levels of CTNNβ1, LEF1 (p < 0.05), and TCF4 (p < 0.01) by CRABP1 knockdown.

CONCLUSIONS

This study found that CRABP1 influences the expression of important genes within the Wnt/β-catenin signaling pathway and promotes DPC proliferation. This investigation provides a theoretical framework to explain the mechanisms that control hair follicle morphogenesis and development.

Shh Gene Regulates the Proliferation and Apoptosis of Dermal Papilla Cells to Affect Its Differential Expression in Secondary Hair Follicle Growth Cycle of Cashmere Goats

Sonic hedgehog (Shh) is a component of the Hedgehog signaling pathway, playing an important role in regulating cell proliferation, differentiation, apoptosis, and the repair of damaged organisms. To further clarify the expression pattern of Shh gene in the secondary hair follicle growth cycle of cashmere goats and its mechanism of action on secondary hair follicle papilla cells, and improve cashmere quality, in this study, we took Inner Mongolia Albas white cashmere goats as the research objects and collected skin samples at different growth stages to obtain secondary hair follicles, detected Shh and its gene expression by RT-qPCR, Western blot, immunohistochemistry, and other techniques, while we also cultured DPCs in vitro. Shh gene overexpression and interference vectors were constructed, and the effects of Shh gene on the proliferation and apoptosis of DPCs were studied through cell transfection technology. The results showed that there are significant differences in Shh and its gene expression in the secondary hair follicle growth cycle skins of cashmere goats, with the highest expression level in anagen, followed by catagen, and the lowest expression level in telogen. Shh was mainly expressed in the inner root sheath, outer root sheath, and secondary hair follicle papilla. After the overexpression of Shh gene, the proliferation and vitality of the hair papilla cells were enhanced compared to the interference group. After Shh gene interference, the apoptosis rate of the cells increased, indicating that Shh gene can regulate downstream Ptch, Smo, and Gli2 gene expression to promote the proliferation of DPCs, and thus form its expression pattern in the secondary hair follicle growth cycle of cashmere goats.

Therapeutic effect of Nepenthes kampotiana Lecomte ethanol extract (Nk-EE) on androgenic alopecia through the inhibition of apoptosis and 5α-reductase activity

There is increasing interest in hair loss treatment because a growing number of people affected. Nepenthes kampotiana Lecomte is known for its anticancer effects, but its potential for preventing hair loss has not been researched. Therefore, this study focused on the hair loss prevention effects of N. kampotiana Lecomte ethanol extract (Nk-EE). The results showed that Nk-EE had a proliferative effect on human follicle dermal papilla cells and inhibited cell death. In vivo experiments using androgenic areata models showed that Nk-EE had a positive effect on a variety of biomarkers such as hair-to-skin ratio, hair type frequency, and hair thickness. The results of this study suggest that Nk-EE has potential as an effective treatment for androgenic alopecia.

Efficacy of a wheat polar lipid complex in reducing hair loss and improving hair growth in healthy women: A randomized, double-blind, placebo-controlled clinical study

OBJECTIVE

Hair loss is a major source of psychological distress for affected people. Safe and natural ingredients are therefore needed to help reduce hair loss and stimulate hair growth. This pilot clinical study aimed at exploring the efficacy of a wheat polar lipid complex (WPLC, Ceramosides™), containing sphingolipids and digalactosyl diglycerides, on hair characteristics improvement in women showing acute hair shedding.

METHODS

Sixty-six women presenting a proportion of hair in the telogen phase greater than 15% were recruited and allocated to two groups, each including at least 10 postmenopausal women. For 84 days, participants consumed 30 mg/day of the WPLC supplement, or the placebo. Their hair characteristics were assessed after 56 and 84 days using phototrichogram evaluations of hairs in anagen/telogen phases, measuring hair shedding by a pull test, hair diameter and elongation at break point, hair growth and scalp sebum content. Hair density and volume were also clinically evaluated. All these parameters were also investigated in the subgroup of postmenopausal women.

RESULTS

WPLC supplementation decreased telogen hair density/proportion while increasing the anagen hair density/proportion. These effects were significant compared with the placebo as early as within 56 days. It also led to reduced hair shedding upon pull test analyses. If no changes were evidenced in hair diameter, WPLC improved hair growth and resistance to breakage after 84 days. Clinical evaluations also showed hair density and volume improvement. Furthermore, supplementation decreased scalp sebum content in women with oily hair. The beneficial effects were also observed in the subgroup of postmenopausal women. Finally, WPLC supplementation improved participants' perception of their hair conditions.

CONCLUSION

Through a reducing effect on hair shedding and a stimulating effect on hair reappearance and growth, WPLC dietary supplementation was shown to significantly reduce hair loss in women.

MDIC3: Matrix decomposition to infer cell-cell communication

Crosstalk among cells is vital for maintaining the biological function and intactness of systems. Most existing methods for investigating cell-cell communications are based on ligand-receptor (L-R) expression, and they focus on the study between two cells. Thus, the final communication inference results are particularly sensitive to the completeness and accuracy of the prior biological knowledge. Because existing L-R research focuses mainly on humans, most existing methods can only examine cell-cell communication for humans. As far as we know, there is currently no effective method to overcome this species limitation. Here, we propose MDIC3 (matrix decomposition to infer cell-cell communication), an unsupervised tool to investigate cell-cell communication in any species, and the results are not limited by specific L-R pairs or signaling pathways. By comparing it with existing methods for the inference of cell-cell communication, MDIC3 obtained better performance in both humans and mice.

Low Molecular Weight Collagen Peptide (LMWCP) Promotes Hair Growth by Activating the Wnt/GSK-3β/β-Catenin Signaling Pathway

Low molecular weight collagen peptide (LMWCP) is a collagen hydrolysate derived from fish. We investigated the effects of LMWCP on hair growth using human dermal papilla cells (hDPCs), human hair follicles (hHFs), patch assay, and telogenic C57BL/6 mice, while also examining the underlying mechanisms of its action. LMWCP promoted proliferation and mitochondrial potential, and the secretion of hair growth-related factors, such as EGF, HB-EGF, FGF-4, and FGF-6 in hDPCs. Patch assay showed that LMWCP increased the neogeneration of new HFs in a dose-dependent manner. This result correlated with an increase in the expression of dermal papilla (DP) signature genes such as, ALPL, SHH, FGF7, and BMP-2. LMWCP upregulated phosphorylation of glycogen synthase kinase-3β (GSK-3β) and β-catenin, and nuclear translocation of β-catenin, and it increased the expression of Wnt3a, LEF1, VEGF, ALP, and β-catenin. LMWCP promoted the growth of hHFs and increased the expression of β-catenin and VEGF. Oral administration of LMWCP to mice significantly stimulated hair growth. The expression of Wnt3a, β-catenin, PCNA, Cyclin D1, and VEGF was also elevated in the back skin of the mice. Furthermore, LMWCP increased the expression of cytokeratin and Keratin Type I and II. Collectively, these findings demonstrate that LMWCP has the potential to increase hair growth via activating the Wnt/β-catenin signaling pathway.

Life of the B10 Mouse: A View from the Hair Follicles and Tissue Stem Cells

In our series of studies, the changes in the skin characteristics of mice caused by aging were investigated in correlation with the stem cells for keratinocytes and melanocytes in the natural hair cycle until middle age. The aim of the present review was to investigate these characteristics of hair follicles (HFs) at older age and complete the analysis of these changes as a study throughout the mouse lifetime. In addition, stem cells for keratinocytes and melanocytes were evaluated for changes in skin characteristics caused by aging. Postnatal day 200 (P200) appears to be the age of complete maturation of skin and the onset of aging with regard to HFs. Keratin 15-positive keratinocyte stem cells complete their localization as a quantitatively sufficient amount of progenitor in the hair bulge region and orchestrate the regeneration of hairs in every anagen phase thereafter. Although their frequency is low, an unusual structure of HFs, curved HFs, appear for the first time at P200. Thereafter, abnormal hair curvature continues to increase throughout life. In contrast, HF characteristics derived from melanocytes begin to show a high frequency of hypopigmented hair bulbs at P200 and appear to lead to a significant increase in the number of white hairs. Curved HFs and white hairs were considered biomarkers of aging in mice. The number of tyrosinase-related protein 2-positive melanocyte stem cells in the hair bulge is extremely low and may be one cause underlying not only the induction of melanocyte-derived characteristics by aging but possibly also that of keratinocyte-derived characteristics. These results provide insight into the mechanisms of the actions of stem cells on hair regeneration through the aging process.

BFNB Enhances Hair Growth in C57BL/6 Mice through the Induction of EGF and FGF7 Factors and the PI3K-AKT-β-Catenin Pathway

The objective of this study was to investigate the potential effects of a formulation derived from the bioactive fraction of nanostructured Bacopa procumbens (BFNB) on the promotion of hair growth in C57BL/6 mice. The characterization of the follicular phases and histomorphological analysis showed that the topical application of the formulation for 15 days significantly increased pigmentation and hair growth on the dorsum and head of the mice. Additionally, an acceleration of the follicular cycle phases was observed, along with an increase in the number of follicles, hair length, and diameter, compared to mice treated with minoxidil. In silico analysis and molecular characterization demonstrated that BFNB enhances the expression of epidermal growth factor (EGF) and fibroblast growth factor 7 (FGF7), activating the PI3K-AKT-β-catenin signaling pathway, as well as the expression of PCNA, KI-67, Cyclin D1, and Cyclin E, regulating the cell cycle and cell proliferation, crucial events for hair regeneration. Our results strongly suggest the utility of BFNB as a therapeutic alternative to stimulate hair growth and promote hair health.

Investigating the morphology and genetics of scalp and facial hair characteristics for phenotype prediction

Microscopic traits and ultrastructure of hair such as cross-sectional shape, pigmentation, curvature, and internal structure help determine the level of variations between and across human populations. Apart from cosmetics and anthropological applications, such as determining species, somatic origin (body area), and biogeographic ancestry, the evidential value of hair has increased with rapid progression in the area of forensic DNA phenotyping (FDP). Individuals differ in the features of their scalp hair (greying, shape, colour, balding, thickness, and density) and facial hair (eyebrow thickness, monobrow, and beard thickness) features. Scalp and facial hair characteristics are genetically controlled and lead to visible inter-individual variations within and among populations of various ethnic origins. Hence, these characteristics can be exploited and made more inclusive in FDP, thereby leading to more comprehensive, accurate, and robust prediction models for forensic purposes. The present article focuses on understanding the genetics of scalp and facial hair characteristics with the goal to develop a more inclusive approach to better understand hair biology by integrating hair microscopy with genetics for genotype-phenotype correlation research.

An extract of Leontopodium alpinum inhibits catagen development ex vivo and increases hair density in vivo

Objectives

Hair loss and reduction in hair volume are hallmarks of hair disorders, such as telogen effluvium, or male or female pattern hair loss, and hair ageing, which can cause severe distress in both men and women. Common anti‐hair loss drugs carry some side effects; therefore, novel, safer approaches targeting milder phenotypes are highly advocated. In this context, we investigated an extract of the alpine plant Edelweiss, Leontopodium alpinum var. Helvetia, for its ability to modulate hair follicle (HF) growth ex vivo and inhibit hair loss while increasing hair regeneration in vivo.

Methods

Human amputated HFs were microdissected from three donors, two women and one man, and cultured ex vivo for 6 days. After treatment with 0.001% Edelweiss extract (EWDE), we investigated hair shaft production and anagen/catagen conversion, and measured known parameters associated with hair growth, that is hair matrix keratinocyte proliferation and apoptosis, dermal papilla inductivity, and growth factors, by quantitative (immuno)histomorphometry. To assess the anti‐hair loss potential of the alpine plant compound, we performed a randomized, placebo‐controlled human study enrolling Caucasian women and men, aged 18 to 65 years, with normal hair loss. After 5 months’ daily use of an extract containing leave‐on serum, we analysed hair density and anagen‐to‐catagen/telogen ratio by the Trichogram analysis.

Results

Our results revealed a significant prolongation in the anagen phase in HFs treated with 0.001% Edelweiss, as indicated by an increase in HFs remaining in anagen and a significant decrease in hair cycle score. In line with this effect, EWDE significantly stimulated hair matrix (HM) keratinocyte proliferation, and dermal papilla inductivity, as shown by a significant up‐regulation of versican expression and alkaline phosphatase activity, and a tendential increase in FGF7 immunoreactivity in the dermal papilla of all HFs or only anagen VI HFs. Corroborating the ex vivo results, we observed a significant increase in growing hair shaft numbers (hair density) after treatment with Edelweiss extract formulation, and a tendential up‐regulation in the anagen‐to‐catagen/telogen ratio.

Conclusions

We show here, through several lines of evidence, that the selected extract of the alpine plant Leontopodium alpinum var Helvetia (Edelweiss) inhibits premature catagen induction, possibly by stimulating dermal papilla inductivity. It is therefore worth exploiting this extract clinically as an anti‐hair loss agent, both for preventing ageing‐associated hair shedding and as an adjuvant therapy for hair loss disorders.

Modulation of Hair Growth Promoting Effect by Natural Products

A large number of people suffer from alopecia or hair loss worldwide. Drug-based therapies using minoxidil and finasteride for the treatment of alopecia are available, but they have shown various side effects in patients. Thus, the use of new therapeutic approaches using bioactive products to reduce the risk of anti-hair-loss medications has been emphasized. Natural products have been used since ancient times and have been proven safe, with few side effects. Several studies have demonstrated the use of plants and their extracts to promote hair growth. Moreover, commercial products based on these natural ingredients have been developed for the treatment of alopecia. Several clinical, animal, and cell-based studies have been conducted to determine the anti-alopecia effects of plant-derived biochemicals. This review is a collective study of phytochemicals with anti-alopecia effects, focusing mainly on the mechanisms underlying their hair-growth-promoting effects.

Niacinamide Down-Regulates the Expression of DKK-1 and Protects Cells from Oxidative Stress in Cultured Human Dermal Papilla Cells

Purpose

An increasing number of people are suffering from hair loss disorders. Niacinamide has long been used as an active ingredient for anti-hair loss preparations but the exact mechanism has not been clearly elucidated yet. The effects of niacinamide were investigated in cultured human dermal papilla cells (hDPCs).

Methods

To investigate the anti-hair loss effect of niacinamide and its molecular mechanisms, Western blot analysis, ELISA, quantitative RT-PCR and immunocytochemistry were performed. To study the protective effects of niacinamide against H₂O₂-induced oxidative stress, ROS generation and cytotoxicity were evaluated by DCF-DA assay and LDH release assay, respectively. Minoxidil was used as a positive control.

Results

Niacinamide decreased the protein expression level of DKK-1 which promotes regression of hair follicles by inducing catagen. The protein expression levels of cell senescence markers, p21 (CDKN1A) and p16 (CDKN2A) which are related to cell cycle arrest, were decreased. The expression of versican was increased by niacinamide treatment in cultured hDPCs. We have found that niacinamide decreased the H₂O₂-induced intracellular ROS production in cultured hDPCs. Moreover, niacinamide decreased the protein expression levels of H₂O₂-induced p21 and p16 and diminished the secretion of H₂O₂-induced DKK-1.

Conclusion

Our data demonstrate that niacinamide could enhance hair growth by preventing oxidative stress-induced cell senescence and premature catagen entry of hair follicles.

Hair Growth-Promoting Mechanisms of Red Ginseng Extract through Stimulating Dermal Papilla Cell Proliferation and Enhancing Skin Health

This study aimed to investigate the underlying mechanisms of red ginseng extract (RGE) on regulating hair growth and hair follicle development. Results from in vitro studies showed that RGE treatment simultaneously enhanced viability and inhibited apoptosis in human hair dermal papilla cells. Moreover, RGE administration promoted telogen-to-anagen transition, prolonged anagen in hair follicular cycling, and increased the size of hair follicles and skin thickness in a C57BL/6 mouse model. Furthermore, RGE treatment significantly upregulated the expression of β-catenin, phospho-glycogen synthase kinase 3β, cyclin D1, cyclin E, and Bcl-2, phospho-extracellular signal-regulated protein kinase, and phospho-Akt, which are associated with promoting hair growth. In addition, RGE enhanced skin health by activation of antiox-idant defense systems. Our data demonstrates that hair regenerative mechanisms of RGE may be mediated by stimulating dermal papilla cell proliferation and enhancing skin functions.

Triboelectric Nanogenerators for Therapeutic Electrical Stimulation

Current solutions developed for the purpose of in and on body (IOB) electrical stimulation (ES) lack autonomous qualities necessary for comfortable, practical, and self-dependent use. Consequently, recent focus has been placed on developing self-powered IOB therapeutic devices capable of generating therapeutic ES for human use. With the recent invention of the triboelectric nanogenerator (TENG), harnessing passive human biomechanical energy to develop self-powered systems has allowed for the introduction of novel therapeutic ES solutions. TENGs are especially effective at providing ES for IOB therapeutic systems given their bioconformability, low cost, simple manufacturability, and self-powering capabilities. Due to the key role of naturally induced electrical signals in many physiological functions, TENG-induced ES holds promise to provide a novel paradigm in therapeutic interventions. The aim here is to detail research on IOB TENG devices applied for ES-based therapy in the fields of regenerative medicine, neurology, rehabilitation, and pharmaceutical engineering. Furthermore, considering TENG-produced ES can be measured for sensing applications, this technology is paving the way to provide a fully autonomous personalized healthcare system, capable of IOB energy generation, sensing, and therapeutic intervention. Considering these grounds, it seems highly relevant to review TENG-ES research and applications, as they could constitute the foundation and future of personalized healthcare.

Red ginseng oil promotes hair growth and protects skin against UVC radiation

Background

A wide range of environmental factors, such as diseases, nutritional deficiencies, ageing, hormonal imbalances, stress, and ultraviolet (UV) radiation, may affect the structure and function of the skin that covers the entire surface of the human body. In this study, we investigated roles of red ginseng oil (RGO) in enhancing skin functions, including hair growth and skin protection, using mouse models.

Methods

For hair growth experiment, shaved dorsal skins of C57BL/6 mice were topically applied with vehicle, RGO, RGO's major compounds, or minoxidil for consecutive 21 days and skin tissues were examined the hair growth promoting capacity. For skin protection experiment, SKH-1 hairless mice were topically applied with vehicle or RGO twice a day for three days prior to exposure to UVC radiation at 20 kJ/cm². Skin tissues were collected to evaluate skin protective effects of RGO.

Results

Topical application of RGO to C57BL/6 mice effectively promoted hair regeneration by inducing early telogen-to-anagen transition and significantly increasing the density and bulb diameter of hair follicles. Major compounds, including linoleic acids and β-sitosterol, contributed to RGO-promoted hair growth. Treatment with RGO as well as its major components upregulated expression of hair growth–related proteins. Furthermore, in SKH-1 hairless mice, RGO had a protective effect against UVC-induced skin damage by inhibiting inflammation and apoptosis, as well as inducing cytoprotective systems.

Conclusion

These data suggest that RGO may be a potent agent for improving skin health and thereby preventing and/or treating hair loss and protecting skin against UV radiation.

Effect of cysteine-free human fibroblast growth factor-5s mutant (FGF5sC93S) on hair growth

Treatment for hair loss is largely limited, and any beneficial effects are often transient. Based on the critical role of the FGF5 isoform, FGF5s, in the hair growth cycle, it may be a good therapeutic candidate for the prevention of hair loss, as well as the promotion of hair growth. To investigate its potential use for hair growth, a mutant form of the FGF5s protein (FGF5sC93S) was generated, expressed, and purified. The FGF5sC93S mutant was able to antagonize FGF5-induced mitogenic activity, which normally triggers the conversion of hair follicles from the anagen phase to the catagen phase. In addition, the FGF5sC93S mutant efficiently suppressed gene expression induced by FGF5 both human outer root sheath (hORS) and human dermal papilla (hDP) cells. Administration of FGF5sC93S proteins onto the scalps of human subjects significantly increased the total number of hairs at 24 weeks. Together, our data demonstrate that a mutant form of the FGF5s protein could be used as a potential hair promoting agent.

Efficacy and safety of a novel herbal solution for the treatment of androgenetic alopecia and comparison with 5% minoxidil: A double-blind, randomized controlled trial study

FDA-approved drugs for the most common type of hair loss, androgenetic alopecia (AGA), present many side effects and disadvantages. However, herbal compounds are characterized by patient compliance, fewer side effects, and several mechanisms of action. The present study set to evaluate the effectiveness and safety of the topical herbal solution and to compare it with 5% minoxidil in men with AGA. A randomized, double-blind controlled trial was conducted from 28 November 2018 to 2 September 2019, in Sina Hospital, Tabriz, Iran. 24 healthy males (mean [SD] age 33.04 [5.81]) with mild to moderate AGA were selected from 44 volunteer participants. Participants were randomly assigned (1:1) into two groups. They received 1 ml of topical solutions at morning and evening intervals for 9 months. Primary outcomes consisted of measured hair diameters at baseline and repeated at weeks 12, 24, and 36. Furthermore, hair density was measured at baseline and week 36. The MTS + THS group was significantly superior to the MTS group after 36 weeks of therapy in the hair diameter improvement. At week 36, the mean hair diameter of the MTS + THS group significantly increased compared to the MTS group (P = .001). Hair density increased in both groups; however, only in the MTS + THS group, it was significant (P < .05). The findings established that the topical herbal solution has significant influence on patients with AGA and improvement of their quality of life. This solution can be considered a significant step towards the prevention and treatment of AGA. clinicaltrials.gov Identifier: NCT03753113.

Maintaining Hair Inductivity in Human Dermal Papilla Cells: A Review of Effective Methods

The dermal papilla comprises mesenchymal cells in hair follicles, which play the main role in regulating hair growth. Maintaining the potential hair inductivity of dermal papilla cells (DPCs) and dermal sheath cells during cell culture is the main factor in in vitro morphogenesis and regeneration of hair follicles. Using common methods for the cultivation of human dermal papilla reduces the maintenance requirements of the inductive capacity of the dermal papilla and the expression of specific dermal papilla biomarkers. Optimizing culture conditions is therefore crucial for DPCs. Moreover, exosomes appear to play a key role in regulating the hair follicle growth through a paracrine mechanism and provide a functional method for treating hair loss. The present review investigated the biology of DPCs, the molecular and cell signaling mechanisms contributing to hair follicle growth in humans, the properties of the dermal papilla, and the effective techniques in maintaining hair inductivity in DPC cultures in humans as well as hair follicle bioengineering.

Changes in characteristics of murine hair follicles and tissue stem cells by aging

The aging process is closely related to the organization of stem cells, and skin is thought to be one of the suitable models for its investigation. We have focused on the murine hair follicle to verify this idea because it shows typical aging phenotypes and is a self-renewing structure reconstituted by its own stem cells. However, how changes in the characteristics of the hair follicle and in the behavior of tissue stem cells in the natural hair cycle occur are not fully understood. We investigated the number, morphology and pigmentation of hair follicles in anagen phases during the aging process. In addition, stem cells for keratinocytes and melanocytes were examined to evaluate the correlation between changes in skin characteristics and the stem cells. The remarkable changes caused by aging appeared to be the significant increase in qualitative phenotypes such as curved hair follicles and white hair. A significant difference between the number of keratinocyte and melanocyte stem cells in the hair bulge region is likely to be involved in these changes. Our findings may be important for understanding the mechanisms of the actions of stem cells on hair regeneration and for clarifying the mechanisms of age-related phenotypes.

Macrophage-Derived Extracellular Vesicle Promotes Hair Growth

Hair loss is a common medical problem affecting both males and females. Dermal papilla (DP) cells are the ultimate reservoir of cells with the potential of hair regeneration in hair loss patients. Here, we analyzed the role of macrophage-derived Wnts (3a and 7b) and macrophage extracellular vesicles (MAC-EVs) in promoting hair growth. We studied the proliferation, migration, and expression of growth factors of human-DP cells in the presence or absence of MAC-EVs. Additionally, we tested the effect of MAC-EV treatment on hair growth in a mouse model and human hair follicles. Data from western blot and flow cytometry showed that MAC-EVs were enriched with Wnt3a and Wnt7b, and more than 95% were associated with their membrane. The results suggest that Wnt proteins in MAC-EVs activate the Wnt/β-catenin signaling pathways, which leads to activation of transcription factors (Axin2 and Lef1). The MAC-EVs significantly enhanced the proliferation, migration, and levels of hair-inductive markers of DP cells. Additionally, MAC-EVs phosphorylated AKT and increased the levels of the survival protein Bcl-2. The DP cells treated with MAC-EVs showed increased expression of vascular endothelial growth factor (VEGF) and keratinocyte growth factor (KGF). Treatment of Balb/c mice with MAC-EVs promoted hair follicle (HF) growth in vivo and also increased hair shaft size in a short period in human HFs. Our findings suggest that MAC-EV treatment could be clinically used as a promising novel anagen inducer in the treatment of hair loss.

Extract of Plumbago zeylanica enhances the growth of hair follicle dermal papilla cells with down-regulation of 5α-reductase type II

BACKGROUND

Cellular senescence, a phenomenon of irreversible growth arrest of mammalian cells, is involved in various age-related phenomena in organisms. Hair follicle dermal papilla (DP) cells play important roles in the regulation of hair growth and loss.

AIMS

We examined the implication of cellular senescence of DP cells in androgenetic alopecia (AGA), the most common form of male hair loss, and searched for the compounds that have a beneficial effect on the prevention of AGA.

PATIENTS/METHODS

Expression of the 5α-reductase type II (SRD5A2) gene, which plays a key role in the development of AGA, was examined by quantitative RT-PCR and Western blotting analysis in DP cells. Besides, DP cells were cultured with the extracts of herbs used in traditional Ayurvedic medicine to search for the compounds that have a beneficial effect on the growth of DP cells.

RESULTS

We found that expression of the SRD5A2 was up-regulated in senescent DP cells. We also found that the herbal extract of Plumbago zeylanica (root) enhanced the growth of DP cells and down-regulated the expression of SRD5A2 in DP cells. Further, plumbagin, an ingredient of P zeylanica, would be responsible for the above effects of P zeylanica.

CONCLUSION

These results suggested the possibility that senescent DP cells may have a role in the development of AGA through up-regulating SRD5A2 expression, and the P zeylanica extract and plumbagin may suppress its development through enhancing the growth of DP cells and down-regulating SRD5A2 expression in DP cells.

Insufficient liver maturation affects murine early postnatal hair cycle

Abnormal hair loss results from a variety of factors, such as metabolic dysfunctions, immunodeficiency, and environmental stressors. Here, we report that mutant mice having defects in liver function, develop alopecia. We have shown previously that in mice lacking a Cnot3 gene, which encodes an essential component of the CCR4-NOT deadenylase complex in liver (Cnot3-LKO mice), the liver does not mature properly, resulting in various pathologies such as hepatitis, hepatic necrosis, and anemia. Unexpectedly, Cnot3-LKO mice start to lose hair around postnatal day 17 (P17). The region of hair loss expands all across their backs and symptoms persist until around P28-30. Afterward, hair re-grows, and Cnot3-LKO mice show complete hair recovery by P40. The phenotype is dependent on mouse genotype, indicating that hair follicle morphogenesis and cycling are influenced by abnormal liver development. By performing histological, quantitative PCR, and immunoblot analyses, we detected sebaceous gland (SG) hypertrophy accompanied by an increase of peroxisome proliferator-activated receptor γ (PPARγ). Collectively, these findings suggest that paracrine signaling related to liver function influences hair growth, at least in part, by altering lipid metabolism.

Photobiomodulation for the management of alopecia: mechanisms of action, patient selection and perspectives

Photobiomodulation (PBM) or low-level laser therapy was discovered over 50 years ago, when Mester in Hungary observed regrowth of hair in mice when irradiated with a ruby laser. At the present time, several different PBM devices are marketed to assist with hair regrowth in alopecia patients. This review covers the three main types of alopecia (androgenetic, areata, and chemotherapy-induced), and discusses the mechanism of action of PBM for each disease. The different devices used (mostly low powered red laser diodes), dosimetry, animal models, and clinical trials are summarized. Criteria for patient selection are outlined. Finally a perspectives section looks forward to the future.

Adipose-derived cellular and cell-derived regenerative therapies in dermatology and aesthetic rejuvenation

Cellular and cell-derived components of adipose-derived tissue for the purposes of dermatologic and aesthetic rejuvenation applications have become increasingly studied and integrated into clinical practice. These components include micro-fragmented fat (nanofat), the stromal vascular fraction (SVF), adipose-derived mesenchymal stem cells (ASC), and extracellular vesicles (EVs), which have all shown capability to repair, regenerate, and rejuvenate surrounding tissue. Various aesthetic applications including hair growth, scar reduction, skin ischemia-reperfusion recovery, and facial rejuvenation are reviewed. In particular, results from preclinical and clinical studies are discussed, with a focus on clarification of nomenclature.

"Miliacin encapsulated by polar lipids stimulates cell proliferation in hair bulb and improves telogen effluvium in women"

BACKGROUND

Miliacin, the main triterpenoid from millet, is known to stimulate keratinocyte metabolism and proliferation. Polar lipids are able to form vesicles with active compounds and to improve their bioavailability.

OBJECTIVES

We aimed to demonstrate potential benefits of a solution of miliacin encapsulated within polar lipids (MePL) on telogen effluvium prevention and hair condition in women.

METHODS

After preliminary cell proliferation studies, a placebo-controlled, multicentric, randomized, double-blind trial was performed on sixty-five nonmenopausal women affected by telogen effluvium, to assess the efficacy of a 12-week oral supplementation with MePL. Telogen and anagen densities were determined by phototrichogram analysis. Scalp dryness and hair brightness were clinically evaluated using a Likert scale.

RESULTS

MePL further enhanced cell proliferation in hair bulb from human scalp than miliacin alone. Compared to the placebo treatment, MePL supplementation significantly reduced telogen density after 12 weeks of treatment. An increase of anagen density was observed in both groups, although there was no significant difference between the two treatments. Scalp dryness was more decreased in the MePL group than in the placebo group. A better improvement of hair brightness was also observed after 12 weeks of supplementation with MePL.

CONCLUSION

Twelve weeks of MePL supplementation significantly reduced the hair density in the telogen phase and, in parallel, improved scalp dryness and hair condition. These effects could be linked to MePL activity on cell proliferation in hair bulb. MePL is an original association of plant extract that could help to prevent and/or limit hair loss in women.

Effects of gamma rays on the regeneration of murine hair follicles in the natural hair cycle

PURPOSE

This review evaluates the effects of γ-rays on the regeneration of murine hair follicles in the natural hair cycle. A series of studies were performed to investigate this issue, in which the whole bodies of C57BL/10JHir mice in the 1st telogen phase of the hair cycle were irradiated with γ-rays.

RESULTS

The dermis of the irradiated skin showed a decrease in hair follicle density and induction of curved hair follicles along with the presence of white hairs and hypopigmented hair bulbs in the 2nd and 3rd anagen phases. An increased frequency of hypopigmented hair bulbs was still observed in the later hair cycle at postnatal day 200. There was no significant difference in the number of stem cells in the hair bulge region between control and irradiated skin.

CONCLUSIONS

These results show that the effects of γ-rays on the pigmentation of murine hair follicles are persistently carried over to later hair cycles, although those on the number and structure of hair follicles appear to be hidden by the effects of aging. Our findings may be important for understanding the mechanisms of the actions of stem cells on hair regeneration in connection with age-related phenotypes.

Endocrine evaluation of hirsutism

Hirsutism is defined as excessive terminal hair growth in a male pattern in females. It typically affects 5 to 10% of reproductive-age women. Excessive hair growth can often cause significant psychological and emotional distress. As a result, hirsutism is a common presenting complaint to healthcare professionals, including dermatologists, as women search for cosmetic and medical solutions to their problem. Hirsutism results from excess production of androgens, often from ovarian or adrenal sources. It is typically associated with a metabolic syndrome like polycystic ovarian syndrome (PCOS), but can be idiopathic or medication-induced. This article provides an endocrine perspective for the evaluation and management of hirsutism.

Therapeutic role of human hepatocyte growth factor (HGF) in treating hair loss

Hepatocyte growth factor (HGF) is a paracrine hormone that plays an important role in epithelial-mesenchymal transition. HGF secreted by mesenchymal cells affects many properties of epithelial cells, such as proliferation, motility, and morphology. HGF has been reported to promote follicular growth. The purpose of the present study is to investigate the therapeutic role of HGF in hair loss treatment. A recombinant vector containing the human HGF (hHGF) gene (pTARGET-hHGF) was constructed, and the expression of hHGF in vitro was quantitatively and qualitatively evaluated. The effect of hHGF on hair growth was tested in mice, and results demonstrated that pTARGET-hHGF was successfully delivered into fibroblasts in vitro leading to a high expression of hHGF. Local injections of the pTARGET-hHGF recombinant vector into mice resulted in multiple beneficial effects compared to placebo, including faster hair regeneration, improved follicle development, and significantly increased HGF receptor (HGF-R). In conclusion, we have established a nonviral vector of hHGF which could be utilized to manipulate the sheath fibroblasts surrounding hair follicles (HF), thereby stimulating hair regeneration.

Topical Application of Oleuropein Induces Anagen Hair Growth in Telogen Mouse Skin

We observed that oleuropein, the main constituent of the leaves and unprocessed olive drupes of Olea europaea, protected mice from high-fat diet-induced adiposity by up-regulation of genes involved in Wnt10b-mediated signaling in adipose tissue. The activation of Wnt/β-catenin pathway is also well established to positively regulate the anagen phase of hair growth cycle in mice skin.

Endocrine evaluation of hirsutism

Hirsutism is defined as excessive terminal hair growth in a male pattern in females. It typically affects 5 to 10% of reproductive-age women. Excessive hair growth can often cause significant psychological and emotional distress. As a result, hirsutism is a common presenting complaint to healthcare professionals, including dermatologists, as women search for cosmetic and medical solutions to their problem. Hirsutism results from excess production of androgens, often from ovarian or adrenal sources. It is typically associated with a metabolic syndrome like polycystic ovarian syndrome (PCOS), but can be idiopathic or medication-induced. This article provides an endocrine perspective for the evaluation and management of hirsutism.

Drug discovery for alopecia: gone today, hair tomorrow

INTRODUCTION

Hair loss or alopecia affects the majority of the population at some time in their life, and increasingly, sufferers are demanding treatment. Three main types of alopecia (androgenic [AGA], areata [AA] and chemotherapy-induced [CIA]) are very different, and have their own laboratory models and separate drug-discovery efforts.

AREAS COVERED

In this article, the authors review the biology of hair, hair follicle (HF) cycling, stem cells and signaling pathways. AGA, due to dihydrotesterone, is treated by 5-α reductase inhibitors, androgen receptor blockers and ATP-sensitive potassium channel-openers. AA, which involves attack by CD8(+)NK group 2D-positive (NKG2D(+)) T cells, is treated with immunosuppressives, biologics and JAK inhibitors. Meanwhile, CIA is treated by apoptosis inhibitors, cytokines and topical immunotherapy.

EXPERT OPINION

The desire to treat alopecia with an easy topical preparation is expected to grow with time, particularly with an increasing aging population. The discovery of epidermal stem cells in the HF has given new life to the search for a cure for baldness. Drug discovery efforts are being increasingly centered on these stem cells, boosting the hair cycle and reversing miniaturization of HF. Better understanding of the molecular mechanisms underlying the immune attack in AA will yield new drugs. New discoveries in HF neogenesis and low-level light therapy will undoubtedly have a role to play.

Hair curvature: a natural dialectic and review

Although hair forms (straight, curly, wavy, etc.) are present in apparently infinite variations, each fibre can be reduced to a finite sequence of tandem segments of just three types: straight, bent/curly, or twisted. Hair forms can thus be regarded as resulting from genetic pathways that induce, reverse or modulate these basic curvature modes. However, physical interconversions between twists and curls demonstrate that strict one-to-one correspondences between them and their genetic causes do not exist. Current hair-curvature theories do not distinguish between bending and twisting mechanisms. We here introduce a multiple papillary centres (MPC) model which is particularly suitable to explain twisting. The model combines previously known features of hair cross-sectional morphology with partially/completely separated dermal papillae within single follicles, and requires such papillae to induce differential growth rates of hair cortical material in their immediate neighbourhoods. The MPC model can further help to explain other, poorly understood, aspects of hair growth and morphology. Separate bending and twisting mechanisms would be preferentially affected at the major or minor ellipsoidal sides of fibres, respectively, and together they exhaust the possibilities for influencing hair-form phenotypes. As such they suggest dialectic for hair-curvature development. We define a natural-dialectic (ND) which could take advantage of speculative aspects of dialectic, but would verify its input data and results by experimental methods. We use this as a top-down approach to first define routes by which hair bending or twisting may be brought about and then review evidence in support of such routes. In particular we consider the wingless (Wnt) and mammalian target of rapamycin (mTOR) pathways as paradigm pathways for molecular hair bending and twisting mechanisms, respectively. In addition to the Wnt canonical pathway, the Wnt/Ca(2+) and planar cell polarity (PCP) pathways, and others, can explain many alternatives and specific variations of hair bending phenotypes. Mechanisms for hair papilla budding or its division by bisection or fission can explain MPC formation. Epithelial-to-mesenchymal (EMT) and mesenchymal-to-epithelial (MET) transitions, acting in collaboration with epithelial-mesenchymal communications are also considered as mechanisms affecting hair growth and its bending and twisting. These may be treated as sub-mechanisms of an overall development from neural-crest stem cell (NCSC) lineages to differentiated hair follicle (HF) cell types, thus providing a unified framework for hair growth and development.

Effects of glucocorticoid on human dermal papilla cells in vitro

Glucocorticoid (GC) is synthesized mostly in the adrenal gland and is secreted in response to stressful conditions. The stress-induced increase in systemic GC may mediate diverse types of cellular damage. However, the specific effects of GC on the dermal papilla cells (DPCs) of hair follicles remain unknown, although stress-related hair loss has increased significantly in recent years. The objective of this study was to determine the effect of a synthetic GC, dexamethasone (Dex), on human DPCs in vitro. We evaluated the effects of Dex on cell proliferation, survival, and the expression of growth factors in DPCs. Dex treatment (1μM) significantly reduced the number of viable cells and the expression of the Ki-67 protein, VEGF and HGF were downregulated following treatment of DPCs with Dex. Taken together, we concluded that Dex inhibits human hair growth by inhibiting both the proliferation of, and growth factors expression by, DPCs.

Cyclosporine A stimulated hair growth from mouse vibrissae follicles in an organ culture model

Hypertrichosis is one of the most common side effects of systemic cyclosporine A therapy. It has been previously shown that cyclosporine A induces anagen and inhibits catagen development in mice. In the present study, to explore the mechanisms of cyclosporine A, we investigated the effects of cyclosporine A on hair shaft elongation, hair follicle cell proliferation, apoptosis, and mRNA expression of selected growth factors using an organ culture model of mouse vibrissae. In this model, cyclosporine A stimulated hair growth of normal mouse vibrissae follicles by inhibiting catagen-like development and promoting matrix cell proliferation. In addition, cyclosporine A caused an increase in the expression of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and nerve growth factor (NGF), and inhibited follistatin expression. Our findings provide an explanation for the clinically observed effects of cyclosporine A on hair growth. The mouse vibrissae organ culture offers an attractive model for identifying factors involved in the modulation of hair growth.

Non polycystic ovary syndrome-related endocrine disorders associated with hirsutism

BACKGROUND

Hyperandrogenism refers to classical androgen-dependent signs such as hirsutism, acne and androgenetic alopecia. Hirsutism is the main hyperandrogenic symptom, defined as an excess of body hair in the androgen-sensitive skin regions of the women. In this review, we attempt to focus on the pathogenesis of hirsutism related to disorders other than polycystic ovary syndrome (PCOS). Also, we will discuss their clinical and biochemical features as well as therapeutic options.

DESIGN

Several original articles, meta-analysis and reviews have been screened in the field of hirsutism and hyperandrogenic disorders.

RESULTS

Current English literature including our studies suggests that PCOS is the most common cause of hirsutism. The most important purpose for investigation is to identify those women with androgen-secreting tumours because of their life-threatening potential. In approximately 1-8% of the women with hirsutism, the underlying cause is nonclassical adrenal hyperplasia because of 21-hydroxylase deficiency. Depending on ethnicity and the geographic area, idiopathic hirsutism constitutes 5-17% of the patients with hirsutism. Approximately 3% of hyperandrogenic women were observed to suffer from hyperandrogenic-insulin-resistant acanthosis nigricans syndrome. More rare causes are glucocorticoid resistance syndrome, hyperprolactinemia, acromegaly, Cushing's syndrome and some drugs. Specific causes of hirsutism such as Cushing's syndrome and adrenal/ovarian tumours should be treated specifically. In other patients, pharmacological approach is the mainstay of therapy.

CONCLUSIONS

A number of patients presenting with hirsutism and exhibiting similar features to PCOS may have other underlying diagnoses. Unlike PCOS, some of these disorders can occasionally be life threatening and require prompt diagnosis and treatment.

Induction of hair growth by insulin-like growth factor-1 in 1,763 MHz radiofrequency-irradiated hair follicle cells

Radiofrequency (RF) radiation does not transfer high energy to break the covalent bonds of macromolecules, but these low energy stimuli might be sufficient to induce molecular responses in a specific manner. We monitored the effect of 1,763 MHz RF radiation on cultured human dermal papilla cells (hDPCs) by evaluating changes in the expression of cytokines related to hair growth. The expression of insulin-like growth factor-1 (IGF-1) mRNA in hDPCs was significantly induced upon RF radiation at the specific absorption rate of 10 W/kg, which resulted in increased expression of B-cell chronic lymphocytic leukemia/lymphoma 2 (BCL-2) and cyclin D1 (CCND1) proteins and increased phosphorylation of MAPK1 protein. Exposure to 10 W/kg RF radiation 1 h per day for 7 days significantly enhanced hair shaft elongation in ex vivo hair organ cultures. In RF-exposed follicular matrix keratinocytes in the hair bulb, the expression of Ki-67 was increased, while the signal for terminal deoxynucleotidyl transferase dUTP nick end labeling was reduced. From these results, we suggest that 1,763 MHz RF exposure stimulates hair growth in vitro through the induction of IGF-1 in hDPCs.