Effect of IGF-I on Hair Growth Is Related to the Anti-Apoptotic Effect of IGF-I and Up-Regulation of PDGF-A and PDGF-B

Small molecule agents against alopecia: Potential targets and related pathways

Alopecia has emerged as a global concern, extending beyond the middle-aged and elderly population and increasingly affecting younger individuals. Despite its growing prevalence, the treatment options and effective drugs for alopecia remain limited due to the incomplete understanding of its underlying mechanisms. Therefore, it is urgent to explore the pathogenesis of alopecia and discover novel and safer therapeutic agents. This review provided an overview of the prevailing clinical disorders of alopecia, and the key pathways and targets involved in hair growth process. Additionally, it discusses FDA-approved drugs and clinical candidates for the treatment of alopecia, and explores small molecule compounds with anti-alopecia potential in the drug discovery phase. These endeavors are expected to provide researchers with valuable scientific insights and practical information for anti-alopecia drug discovery.

Interpretation of the Yak Skin Single-Cell Transcriptome Landscape

The morphogenesis of hair follicle structure is accompanied by the differentiation of skin tissue. Mammalian coats are produced by hair follicles. The formation of hair follicles requires signal transmission between the epidermis and dermis. However, knowledge of the transcriptional regulatory mechanism is still lacking. We used single-cell RNA sequencing to obtain 26,573 single cells from the scapular skin of yaks at hair follicle telogen and anagen stages. With the help of known reference marker genes, 11 main cell types were identified. In addition, we further analyzed the DP cell and dermal fibroblast lineages, drew a single-cell map of the DP cell and dermal fibroblast lineages, and elaborated the key genes, signals, and functions involved in cell fate decision making. The results of this study provide a very valuable resource for the analysis of the heterogeneity of DP cells and dermal fibroblasts in the skin and provide a powerful theoretical reference for further exploring the diversity of hair follicle cell types and hair follicle morphogenesis.

Biotherapeutic Applications of Platelet-Rich Plasma in Regenerative Medicine

BACKGROUND

Platelet-rich plasma (PRP), a blood-based product containing platelets and growth factors, is being utilized to treat numerous non-hemostatic disorders. Studies have explored the use of PRP to provide rapid repair, healing, and recovery from various injuries; some studies mentioned the effectiveness of PRP as compared with other forms of treatment like the use of hyaluronic acid. Commercially available PRP systems are available now, and each varies from one another depending on how it is prepared, thus causing variations in platelet concentration and growth factor content. These variations also implicated different therapeutic applications.

METHODS

The paper reviews the various applications of PRP, including factors to consider before using PRP therapy, and provides an extensive list of PRP applications.

RESULTS

The administration of PRP as a standalone treatment or as a co-therapy results in observed positive outcomes. However, there is a lack of standardization for PRP preparation, increasing the risks for heterogeneity and bias amongst results.

CONCLUSION

The use of PRP is indeed an option for regenerative therapy, but more research is needed before it can fully be recommended as a primary treatment modality.

Injections of platelet-rich plasma prepared by automatic blood cell separator combined with topical 5% minoxidil in the treatment of male androgenetic alopecia

BACKGROUND

Platelet-rich plasma (PRP) has been increasingly accepted as a potential therapy in the treatment of androgenetic alopecia (AGA), However, there remains a dearth of data on the effectiveness of PRP prepared by automatic blood cell separator with a combination of topical minoxidil for the treatment of AGA.

OBJECTIVE

To evaluate the efficacy and safety of PRP prepared by automatic blood cell separator combined with topical 5% minoxidil therapy in male AGA.

METHODS

Thirty male patients with mild/moderate AGA were enrolled in a randomized double-blind controlled study. Patients were randomly divided into two treatment arms: (group A) PRP prepared by automatic blood cell separator combined with topical 5% minoxidil group; (group B) PRP prepared by automatic blood cell separator combined with a topical placebo group. Trichoscopic assessments regarding hair density/quantity and mean hair diameter were performed at baseline and follow-up. Clinical efficacy of global photography and patient satisfaction were conducted to verify the therapeutic efficacy of the treatment, and the occurrence of adverse reactions was recorded.

RESULTS

We detected a significant increase in all patients in hair density and quantity after PRP treatment (p < 0.05), and there was no significant difference in mean hair diameter. Although hair density/quantity was more pronounced in group A than in group B, the difference between groups was not statistically significant (p > 0.05). In terms of clinical efficacy and patient satisfaction, group A was superior to group B, and no serious adverse reactions occurred.

CONCLUSION

We hereby conclude that the injections of PRP prepared by an automated method are effective and safe in the treatment of mild-to-moderate male AGA patients, and its combination with topical 5% minoxidil therapy was superior to PRP monotherapy with better clinical efficacy and higher patient satisfaction.

Combination of Transcriptomics and Proteomics Reveals Differentially Expressed Genes and Proteins in the Skin of EDAR Gene-Targeted and Wildtype Cashmere Goats

Cashmere goats play a pivotal role in the animal hair industry and are economically valuable. Cashmere is produced through the periodic growth of secondary hair follicles. To improve their yield of cashmere, the regulatory mechanisms of cashmere follicle growth and development need to be analysed. Therefore, in this study, EDAR gene-targeted cashmere goats were used as an animal model to observe the phenotypic characteristics of abnormal hair growth and development at the top of the head. Transcriptomic and proteomic techniques were used to screen for differentially expressed genes and proteins. In total, 732 differentially expressed genes were identified, including 395 upregulated and 337 downregulated genes. In addition, 140 differentially expressed proteins were identified, including 69 upregulated and 71 downregulated proteins. These results provide a research target for elucidating the mechanism through which EDAR regulates hair follicle growth in cashmere goats. It also enriches the available data on the regulatory network involved in hair follicle growth.

Effect of MNCQQ Cells on Migration of Human Dermal Fibroblast in Diabetic Condition

A major symptom of diabetes mellitus (DM) is unfit hyperglycemia, which leads to impaired wound healing. It has been reported that the migration of fibroblasts can be suppressed under high glucose (HG) conditions. In our previous study, we introduced a serum-free culture method for mononuclear cells (MNCs) called quantity and quality control culture (QQc), which could improve the vasculogenic and tissue regeneration ability of MNCs. In this study, we described a culture model in which we applied a high glucose condition in human dermal fibroblasts to simulate the hyperglycemia condition in diabetic patients. MNC-QQ cells were cocultured with fibroblasts in this model to evaluate its role in improving fibroblasts dysfunction induced by HG and investigate its molecular mechanism. It was proven in this study that the impaired migration of fibroblasts induced by high glucose could be remarkably enhanced by coculture with MNC-QQ cells. PDGF B is known to play important roles in fibroblasts migration. Quantitative PCR revealed that MNC-QQ cells enhanced the gene expressions of PDGF B in fibroblasts under HG. Taken with these results, our data suggested a possibility that MNC-QQ cells accelerate wound healing via improving the fibroblasts migration and promote the gene expressions of PDGF B under diabetic conditions.

Identification of key pathways and genes that regulate cashmere development in cashmere goats mediated by exogenous melatonin

The growth of secondary hair follicles in cashmere goats follows a seasonal cycle. Melatonin can regulate the cycle of cashmere growth. In this study, melatonin was implanted into live cashmere goats. After skin samples were collected, transcriptome sequencing and histological section observation were performed, and weighted gene co-expression network analysis (WGCNA) was used to identify key genes and establish an interaction network. A total of 14 co-expression modules were defined by WGCNA, and combined with previous analysis results, it was found that the blue module was related to the cycle of cashmere growth after melatonin implantation. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the first initiation of exogenous melatonin-mediated cashmere development was related mainly to the signaling pathway regulating stem cell pluripotency and to the Hippo, TGF-beta and MAPK signaling pathways. Via combined differential gene expression analyses, 6 hub genes were identified: PDGFRA, WNT5A, PPP2R1A, BMPR2, BMPR1A, and SMAD1. This study provides a foundation for further research on the mechanism by which melatonin regulates cashmere growth.

Heat-Killed Enterococcus faecalis EF-2001 Induces Human Dermal Papilla Cell Proliferation and Hair Regrowth in C57BL/6 Mice

Minoxidil is the most widely used treatment for hair growth, but has been associated with several side effects. In this study, we investigated the effects of heat-killed Enterococcus faecalis EF-2001 on hair loss prevention and regrowth using human dermal papilla cells and male C57BL/6 mice. To examine the effects of EF-2001, we used minoxidil as the positive control. In the in vitro experiments, EF-2001 treatment (75-500 μg/mL) led to the proliferation of human dermal papilla cells in a concentration-dependent manner. In the in vivo experiment, the topical application of 200 µL EF-2001 on the dorsal surface of C57BL/6 male mice led to hair growth. Changes in hair regrowth were examined by visual comparison and hematoxylin and eosin staining of skin sections. We also determined the expression levels of marker genes (Wnt) and growth factors (fibroblast growth factor, insulin growth factor 1, and vascular endothelial growth factor) in the skin tissues of the back of each mouse using a quantitative polymerase chain reaction. EF-2001 accelerated the progression of hair regrowth in mice and promoted hair-follicle conversion from telogen to anagen, likely by increasing the expression levels of growth factors and marker genes.

Pinus thunbergii bark extract rich in flavonoids promotes hair growth in dorsal skin by regulating inflammatory cytokines and increasing growth factors in mice

Korean maritime pine bark (Pinus thunbergii) has been used as an alternative medicine due to its beneficial properties, including anti-inflammatory effects. To date, the anti-inflammatory and hair growth-promoting effects of Pinus densiflora bark extract have remained elusive. Therefore, in the present study, Pinus thunbergii bark was extracted with pure water (100°C) and the extract was examined to determine its polyphenol and flavonoid content. C57BL/6 mice were used to assess the effects of the extract to promote hair growth. The extract (1, 2 and 4%) was topically applied onto shaved dorsal skin and hair growth was observed for 17 days. A significant increase in hair growth was observed with 2 and 4% extract. Based on this finding, the optimal dose of the extract for effective hair growth promotion was determined to be 2%. The mechanisms of hair growth promotion were investigated via immunohistochemical analysis of changes in inflammatory cytokines and growth factors in the hair follicles following treatment with 2% extract. The treatment reduced the levels of TNF-α and IL-1β, which are pro-inflammatory cytokines, while it enhanced the levels of IL-4 and IL-13, which are anti-inflammatory cytokines, in the hair follicles. In addition, elevated insulin-like growth factor I and vascular epidermal growth factor were detected in hair follicles following treatment. Based on these findings, it was suggested that the extract of Pinus thunbergii bark may be utilized for hair loss prevention and/or hair growth promotion.

Growth Hormone and the Human Hair Follicle

Ever since the discoveries that human hair follicles (HFs) display the functional peripheral equivalent of the hypothalamic-pituitary-adrenal axis, exhibit elements of the hypothalamic-pituitary-thyroid axis, and even generate melatonin and prolactin, human hair research has proven to be a treasure chest for the exploration of neurohormone functions. However, growth hormone (GH), one of the dominant neurohormones of human neuroendocrine physiology, remains to be fully explored in this context. This is interesting since it has long been appreciated clinically that excessive GH serum levels induce distinct human skin pathology. Acromegaly, or GH excess, is associated with hypertrichosis, excessive androgen-independent growth of body hair, and hirsutism in females, while dysfunctional GH receptor-mediated signaling (Laron syndrome) is associated with alopecia and prominent HF defects. The outer root sheath keratinocytes have recently been shown to express functional GH receptors. Furthermore, and contrary to its name, recombinant human GH is known to inhibit female human scalp HFs’ growth ex vivo, likely via stimulating the expression of the catagen-inducing growth factor, TGF-β2. These limited available data encourage one to systematically explore the largely uncharted role of GH in human HF biology to uncover nonclassical functions of this core neurohormone in human skin physiology.

Overexpression of miR-122 promotes apoptosis of dermal papilla cells by directly targeting IGF1R in androgenetic alopecia

Androgenetic alopecia (AGA) is the most common pattern of hair loss resulting from the effects of androgen on hair follicle. MicroRNAs (miRs) serve imperative roles in the regulation of many biological processes of hair follicle. However, the exact molecular mechanism of AGA remains to be elucidated. In the present study, we found miR-122, which is mainly recognized as a tumor suppressor, was highly overexpressed in the bulb of balding HFs in comparison with non-balding ones in AGA. Moreover, miR-122 induces apoptosis of human dermal papilla cells (hDPCs) with miR-122 mimics in vitro, and the expression of insulin-like growth factor 1 receptor (IGF1R) in hDPCs was reduced following upregulation of miR-122. Mechanistically, dual luciferase reporter assay confirmed that miR-122 directly targeted the 3'-untranslated region of IGF1R.These findings suggested that upregulation of miR-122 induces apoptosis, potentially via the repression of IGF1R in hDPCs of AGA, providing a novel insight into the potential pathological mechanism of miR-122 in AGA DPCs. This article is protected by copyright. All rights reserved.

Effects of experimental increase in insulin-like growth factor 1 on feather growth rate, moult intensity and feather quality in a passerine bird

Moulting is a crucial, yet often overlooked life-history stage in many animals, when they renew their integumental structures. This life-history stage is an energetically demanding somatic growth event that has particular importance in birds because feathers play a crucial role in flight, insulation and communication. Somatic growth processes are regulated by the evolutionarily conserved peptide hormone insulin-like growth factor 1 (IGF-1). However, the role of IGF-1 in feather growth remains unknown. In this study, we captured 41 juvenile free-living bearded reedlings (Panurus biarmicus) that had started their first complete moult and brought them into captivity. Then, we manipulated their circulating IGF-1 levels using poly-(lactic-co-glycolid acid) microparticles (microspheres) that provide a sustained release of IGF-1. The treatment increased IGF-1 levels but did not affect the feather growth rate. However, 2 weeks after the treatment, birds in the increased IGF-1 group were moulting more feathers simultaneously than the controls and were at a more advanced stage of moult. Birds with experimentally increased IGF-1 levels had better quality feathers (measured by a lower number of fault bars) than the controls. These results suggest that an increase in IGF-1 does not speed up feather growth, but may alter moult intensity by initiating the renewal of several feathers simultaneously. This may shorten the overall moulting time but may imply costs in terms of IGF-1-induced oxidative stress.

Micro-Current Stimulation Has Potential Effects of Hair Growth-Promotion on Human Hair Follicle-Derived Papilla Cells and Animal Model

Recently, a variety of safe and effective non-pharmacological methods have been introduced as new treatments of alopecia. Micro-current electrical stimulation (MCS) is one of them. It is generally known to facilitate cell proliferation and differentiation and promote cell migration and ATP synthesis. This study aimed to investigate the hair growth-promoting effect of MCS on human hair follicle-derived papilla cells (HFDPC) and a telogenic mice model. We examined changes in cell proliferation, migration, and cell cycle progression with MCS-applied HFDPC. The changes of expression of the cell cycle regulatory proteins, molecules related to the PI3K/AKT/mTOR/Fox01 pathway and Wnt/β-catenin pathway were also examined by immunoblotting. Subsequently, we evaluated the various growth factors in developing hair follicles by RT-PCR in MCS-applied (MCS) mice model. From the results, the MCS-applied groups with specific levels showed effects on HFDPC proliferation and migration and promoted cell cycle progression and the expression of cell cycle-related proteins. Moreover, these levels significantly activated the Wnt/β-catenin pathway and PI3K/AKT/mTOR/Fox01 pathway. Various growth factors in developing hair follicles, including Wnts, FGFs, IGF-1, and VEGF-B except for VEGF-A, significantly increased in MCS-applied mice. Our results may confirm that MCS has hair growth-promoting effect on HFDPC as well as telogenic mice model, suggesting a potential treatment strategy for alopecia.

Effect of Chrysanthemum zawadskii Extract on Dermal Papilla Cell Proliferation and Hair Growth

Background

Chrysanthemum zawadskii (CZ) belongs to the genus Chrysanthemum, also known as ‘Gu-Jeol-Cho’ in Korea. CZ has been used as herbal remedy to manage cough, hypertensive disorders, pharyngitis, bronchitis, gastroenteritis, pneumonia, bladder diseases and common cold. However, its effect on hair growth has not been documented.

Objective

The aim of present study was to elucidate the beneficial effects of CZ on hair growth.

Methods

Proliferation of follicular dermal papilla (DP) cells from human scalp skin was evaluated by MTT assay. The expression of various molecules in DP cells was checked by western blot assay. Effect of CZ extract on the hair growth was evaluated by hair organ culture and C57BL/6 mice model.

Results

Cultivation of DP cells with CZ extract increased cellular proliferation, increased expression of phosphorylated protein kinase B (p-Akt), p-ERK, B-cell lymphoma 2, and decreased expression of Bax. Treatment of human hair follicles with CZ extract significantly enhanced hair growth. Additionally, CZ markedly shortened telogen period, increased anagen transformation and stimulated hair growth in the animal study.

Conclusion

These results suggest that CZ extract has an effect of promoting hair growth and may therefore be a useful a therapeutic remedy for preventing hair loss.

Analysis of lncRNAs Expression Profiles in Hair Follicle of Hu Sheep Lambskin

Lambskin of the Hu sheep exhibits high economic value due to its water-wave pattern. Wool curvature is the key factor of the pattern types and quality of lambskin, and it is formed by the interaction between dermal papilla cells and hair matrix cells in the hair follicle, which is regulated by various genes and signaling pathways. Herein, three full-sibling pairs of two-day-old healthy lambs (n = 6) were divided into a straight wool group (ST) and small waves group (SM) with three repetitions. RNA-seq was applied to determine the expression profile of mRNAs and lncRNAs in Hu sheep hair follicles. 25 differentially expressed mRNAs and 75 differentially expressed lncRNAs were found between SM and ST. FGF12, ATP1B4, and TCONS_00279168 were probably associated with hair follicle development. Then, Gene Ontology (GO) and KEGG enrichment analysis were implemented for the functional annotation of target genes of differentially expressed lncRNAs. The results showed that many genes, such as FGF12 and ATP1B4, were found enriched in PI3K-Akt signaling, MAPK signaling, and Ras signaling pathway associated with hair follicle growth and development. In addition, the interaction network of differentially expressed lncRNAs and mRNAs showed that a total of 6 differentially expressed lncRNAs were associated with 12 differentially expressed mRNAs, which may be as candidate mRNAs and lncRNAs. TCONS_00279168 may target ATP1B4 and FGF12 to regulate MAPK, PI3K-Akt, Ras signaling pathways involved in the sheep hair follicle development process. These results will provide the basis for exploring hair follicle development.

Clinical, trichoscopic, and folliscopic identification of the impact of metabolic syndrome on the response to intradermal dutasteride 0.02% injection in patients with female pattern hair loss: a prospective cohort study

BACKGROUND

No studies investigating the impact of metabolic syndrome (MetS) in treatment response of female pattern hair loss (FPHL).

OBJECTIVE

In this prospective cohort study, we studied the impact of MetS in response to intradermal dutasteride 0.02% injection in patients with FPHL.

METHODS

Fifty-one adult participants with FPHL were classified into study cohorts: with MetS and comparison cohorts without MetS. Both groups underwent clinical, trichoschopic, and digital folliscopic evaluation. Treatment was scheduled over a period of 3 months as four weekly sessions, followed by another four bimonthly sessions. Response was evaluated by digital folliscopy, investigator's, and patient's self assessments at 1 and 3 months post-treatment. Side effects were evaluated.

RESULTS

In participants with MetS, there was a significant reduction of the mean percentage of terminal hair with significant increase of the mean percentage of vellus hair (p = .003, .006, respectively) compared with participants without MetS at 1 month after treatment. These significant differences persisted at 3 months after treatment; for terminal and vellus hair (p = .000) with significant reduction in the mean hair thickness (p = .002) compared with participants without MetS.

CONCLUSIONS

MetS negatively impacted FPHL in terms of response to intradermal injection of dutasteride 0.02% and severity. Further studies are still needed.

Expression Pattern and Role of Klotho in Human Hair Follicles

Background

Klotho protein plays a pivotal role in aging regulation. However, it is unclear whether klotho is expressed in human hair follicles and is correlated with hair growth.

Objective

The purpose of this study was to determine the expression pattern and role of klotho in human hair follicles.

Methods

We examined the klotho expression patterns in human hair follicles from young and aged donors. Furthermore, we examined the functional roles of klotho on human hair growth using klotho siRNA and klotho recombinant protein.

Results

Interestingly, klotho was expressed in human hair follicles at both gene and protein levels. In hair follicles, prominent klotho expression was mainly observed in the outermost regions of the outer root sheath and hair bulb matrix cells. Quantification of klotho protein expression in young and aged donors showed that klotho expression decreased with aging. In human hair follicle organ culture, klotho silencing promoted premature catagen induction and inhibited human hair growth. Otherwise, klotho protein prolonged human hair growth.

Conclusion

These results indicate that klotho might be an important regulatory factor for human hair growth and hair cycle change.

Androgenetic alopecia: combing the hair follicle signaling pathways for new therapeutic targets and more effective treatment options

Introduction: In the past 30 years, only two drugs have received FDA approval for the treatment of androgenetic alopecia reflecting a lack of success in unraveling novel targets for pharmacological intervention. However, as our knowledge of hair biology improves, new signaling pathways and organogenesis processes are being uncovered which have the potential to yield more effective therapeutic modalities. Areas covered: This review focuses on potential targets for drug development to treat hair loss. The physiological processes underlying the promise of regenerative medicine to recreate new functional hair follicles in bald scalp are also examined. Expert opinion: The discovery of promising new targets may soon enable treatment options that modulate the hair cycle to preserve or extend the growth phase of the hair follicle. These new targets could also be leveraged to stimulate progenitor cells and morphogenic pathways to reactivate miniaturized follicles in bald scalp or to harness the potential of wound healing and embryogenic development as an emerging paradigm to generate new hair follicles in barren skin.

Exposure to 50 Hz electromagnetic fields enhances hair follicle regrowth in C57BL/6 mice

IMPACT STATEMENT

In this study, our experiments confirmed that 50 Hz EMF affected hair follicle regrowth, and 50 Hz EMF enhanced K15⁺ stem cells proliferation in the hair bulb and follicular outer root sheath of hair follicles. Those results indicated that 50 Hz EMF may be beneficial for functional healing of hair loss.

Synthesized Ceramide Induces Growth of Dermal Papilla Cells with Potential Contribution to Hair Growth

Background

The ceramide is known to play an important role in the formation of intracellular lipids, and play a crucial role as a barrier for skin and hair cuticle. Recent study has revealed that ceramide has potential effect on hair growth in a mouse model. However, the role of ceramide in human dermal papilla cells (hDPCs) known to play an important role in hair growth is not well understood yet.

Objective

The goal of this study was to investigate the effect of synthetic ceramides (oleyl and stearyl ceramides) on hair growth using hDPCs.

Methods

hDPCs were treated with synthesized ceramides. hDPCs viability was evaluated by MTT assay. The expression of hair growth related factors were investigated by western blot, real-time polymerase chain reaction and growth factor array. The expression of β-catenin was confirmed by immunofluorescence.

Results

Treatment with ceramides increased the expression of proteins affecting cell proliferation such as Bcl-2, BAX, phosphorylated-ERK and Cyclin D1. Also, ceramides treatment were increased the expression of several growth factors, including epidermal growth factor family, and promote the expression of Wnt/β-catenin and BMP2/4 signaling.

Conclusion

Our data suggest that synthetic ceramides stimulates hair growth by induction proliferation of hDPCs via modulation of Wnt/β-catenin and BMP2/4 signaling.

Expression of lipid-protein gene PLP2 in Liaoning cashmere goat

The relationship between PLP2 gene and cashmere fiber quality of Liaoning cashmere goat was investigated. The sheep fibroblast cells were treated with exogenous cytokines and melatonin, independently, and RNA interference, RT-PCR and in situ hybridization were utilized for investigating the PLP2 gene regulation mechanism underlying the Liaoning cashmere growth. The results showed that the expression of PLP2 gene in the prosperous and degenerative stage is higher than that of the primary follicle, indicating that the PLP2 gene promotes the secondary follicle, wherein the gene is expressed only in the inner root sheath, suggesting its correlation to hair loss. The results of RT-PCR showed that the trend of FGF5 expression in PLP2 gene was positively regulated. The influence of MT on the expression of PLP2 gene was negatively regulated, and the inhibition was gradually enhanced with the passage of time. Studies have confirmed that the Noggin gene is an inhibitor of the BMP signaling pathway. After the noggin gene interferes with the lentivirus infection, the expression of the PLP2 gene is downregulated. Therefore, the PLP2 gene, along with the other suppressor genes including the noggin gene, might affect the development of hair follicles by inhibiting the BMP（Bone morphogenetic proteins）pathway.

PDGFA in Cashmere Goat: A Motivation for the Hair Follicle Stem Cells to Activate

The cashmere hair follicle (HF) perpetually goes through cycles of growth, involution and rest. The photoperiod is the main factor in the control of seasonal coat change in cashmere goats while stem cells play a crucial role in the HF growth. Several factors, including Platelet-Derived Growth Factor A (PDGFA), Bone Morphogenetic Protein 2 (BMP2) and Lim-Homeobox gene 2 (LHX2) are implicated in HF morphogenesis and cycle. In this work, the mentioned molecules were investigated to evaluate their role in follicular cycle activation. The study was performed on skin samples collected at different periods of HF cycle and the molecular expression of PDGFA, BMP2 and LHX2 was evaluated by Real-Time PCR (qPCR) at each time point. Since PDGFA showed the most variation, the goat PDGFA gene was sequenced and the protein localization was investigated by immunohistochemistry together with PDGF receptor α (PDGFRα). PDGFA immunostaining was observed in the basal layer of the HF outer root sheath and the immunoreaction appeared stronger in the regressive HFs compared to those in the anagen phase according to qPCR analysis. PDGFRα was observed in the HF epithelium, proving the effect of PDGFA on the follicular structure. The data obtained suggest that PDGFA and BMP2 are both implicated in HF cycle in goat. In particular, PDGFA secreted by the HF is involved in the anagen activation.

Olfactory receptor OR2AT4 regulates human hair growth

Olfactory receptors are expressed by different cell types throughout the body and regulate physiological cell functions beyond olfaction. In particular, the olfactory receptor OR2AT4 has been shown to stimulate keratinocyte proliferation in the skin. Here, we show that the epithelium of human hair follicles, particularly the outer root sheath, expresses OR2AT4, and that specific stimulation of OR2AT4 by a synthetic sandalwood odorant (Sandalore^®) prolongs human hair growth ex vivo by decreasing apoptosis and increasing production of the anagen-prolonging growth factor IGF-1. In contrast, co-administration of the specific OR2AT4 antagonist Phenirat^® and silencing of OR2AT4 inhibit hair growth. Together, our study identifies that human hair follicles can engage in olfactory receptor-dependent chemosensation and require OR2AT4-mediated signaling to sustain their growth, suggesting that olfactory receptors may serve as a target in hair loss therapy.

Increasing evidence suggest that olfactory receptors can carry additional functions besides olfaction. Here, Chéret et al. show that stimulation of the olfactory receptor ORT2A4 by the odorant Sandalore^® stimulates growth of human scalp hair follicles ex vivo, suggesting the use of ORT2A4-targeting odorants as hair growth-promoting agents.

Interconnected PolymerS TeChnology (IPSTiC): An Effective Approach for the Modulation of 5α-Reductase Activity in Hair Loss Conditions

Hair loss represents a condition that adversely affects the social life of patients. The most common cause is androgenetic alopecia (AGA), which is a genetically determined progressive hair-loss condition involving 5α-reductase. In this study, a novel anti-baldness agent based on Interconnected PolymerS TeChnology (IPSTiC), which is an effective strategy for the delivery of bioactive molecules, was developed. This product (IPSTiC patch hair) is based on a polymeric blend consisting of high molecular weight hyaluronic acid and soybean proteins and is able to improve efficacy and stability of bioactive ingredients such as Origanum vulgare leaf extract, Camellia Sinensis leaf extract, and Capsicum Annuum fruit extract. The efficacy of the developed anti-baldness agent was investigated by performing several tests including NO radical and 5α-reductase inhibition assays, stability studies under different conditions, and in vitro diffusion studies using Franz cells. The biocompatibility of IPSTiC patch hair was also evaluated by in vitro analysis of the pro-sensitising potential and EPISKIN model. The obtained results confirmed both the efficacy and safety of IPSTiC patch hair supporting the potential use of this product in the topical treatment of AGA.

Cashmere growth control in Liaoning cashmere goat by ovarian carcinoma immunoreactive antigen-like protein 2 and decorin genes

Objective

The study investigated the biological functions and mechanisms for controlling cashmere growth of Liaoning cashmere goat by ovarian carcinoma immunoreactive antigen-like protein 2 (OCIAD2) and decorin (DCN) genes.

Methods

cDNA library of Liaoning cashmere goat was constructed in early stages. OCIAD2 and DCN genes related to cashmere growth were identified by homology analysis comparison. The expression location of OCIAD2 and DCN genes in primary and secondary hair follicles (SF) was performed using in situ hybridization. The expression of OCIAD2 and DCN genes in primary and SF was performed using real-time polymerase chain reaction (PCR).

Results

In situ hybridization revealed that OCIAD2 and DCN were expressed in the inner root sheath of Liaoning cashmere goat hair follicles. Real-time quantitative PCR showed that these genes were highly expressed in SF during anagen, while these genes were highly expressed in primary hair follicle in catagen phase. Melatonin (MT) inhibited the expression of OCIAD2 and promoted the expression of DCN. Insulin-like growth factors-1 (IGF-1) inhibited the expression of OCIAD2 and DCN, while fibroblast growth factors 5 (FGF5) promoted the expression of these genes. MT and IGF-1 promoted OCIAD2 synergistically, while MT and FGF5 inhibited the genes simultaneously. MT+IGF-1/MT+FGF5 inhibited DCN gene. RNAi technology showed that OCIAD2 expression was promoted, while that of DCN was inhibited.

Conclusion

Activation of bone morphogenetic protein (BMP) signaling pathway up-regulated OCIAD2 expression and stimulated SF to control cell proliferation. DCN gene affected hair follicle morphogenesis and periodic changes by promoting transforming growth factor-β (TGF-β) and BMP signaling pathways. OCIAD2 and DCN genes have opposite effects on TGF-β signaling pathway and inhibit each other to affect the hair growth.

A Summary of New Findings on the Biological Effects of Selenium in Selected Animal Species-A Critical Review

Selenium is an essential trace element important for many physiological processes, especially for the functions of immune and reproductive systems, metabolism of thyroid hormones, as well as antioxidant defense. Selenium deficiency is usually manifested by an increased incidence of retention of placenta, metritis, mastitis, aborts, lowering fertility and increased susceptibility to infections. In calves, lambs and kids, the selenium deficiency demonstrates by WMD (white muscle disease), in foals and donkey foals, it is associated with incidence of WMD and yellow fat disease, and in pigs it causes VESD (vitamin E/selenium deficiency) syndrome. The prevention of these health disorders can be achieved by an adequate selenium supplementation to the diet. The review summarizes the survey of knowledge on selenium, its biological significance in the organism, the impact of its deficiency in mammalian livestock (comparison of ruminants vs. non-ruminants, herbivore vs. omnivore) and possibilities of its peroral administration. The databases employed were as follows: Web of Science, PubMed, MEDLINE and Google Scholar.

Inhibition of 5α-Reductase, IL-6 Secretion, and Oxidation Process of Equisetum debile Roxb. ex Vaucher Extract as Functional Food and Nutraceuticals Ingredients

This study aims to investigate the biological activities related to hair loss of Equisetum debile extracts, including 5α-reductase inhibition, interleukin-6 (IL-6) secretion reduction, and anti-oxidation. E. debile extracts were obtained by maceration in various solvents. Crude extract (CE) was obtained by maceration in 95% ethanol. Chlorophyll-free extract (CF) was the CE which of the chlorophyll has been removed by electrocoagulation. Hexane extract (HE), ethyl acetate extract (EA), and ethanolic extract (ET) were fraction extracts obtained from maceration in hexane, ethyl acetate, and 95% ethanol, respectively. The extracts were investigated for inhibitory activity against 5α-reductase and IL-6 secretion. Total phenolic contents (TPC) were investigated and antioxidant activities were determined by means of 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2′-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. The inhibition of lipid peroxidation was determined by the ferric thiocyanate method. The cytotoxicity of the extracts on dermal papilla cells and irritation test by hen's egg test chorioallantoic membrane assay were also investigated. All extracts could inhibit 5α-reductase and decrease IL-6 secretion in lipopolysaccharide-stimulated macrophage. The antioxidant activity of E. debile extracts was directly related to their TPC. ET which contained the highest TPC (68.8 ± 6.7 mg GA/g) showed the highest equivalent concentration (EC₁) of 289.1 ± 26.4 mM FeSO₄/g, TEAC of 156.6 ± 34.6 mM Trolox/g, and 20.0 ± 6.0% DPPH inhibition. However, EA exhibited the highest inhibition against lipid peroxidation (57.2 ± 0.4%). In addition, EA showed no cytotoxicity on dermal papilla cell line and no irritation on chorioallantoic membrane of hen’s eggs. In conclusion, EA was suggested as the most attractive ingredients for functional food and nutraceuticals because of the high inhibitory activity against 5α-reductase, IL-6 secretion, and lipid peroxidation inhibition.

Bioactives in Chinese Proprietary Medicine Modulates 5α-Reductase Activity and Gene Expression Associated with Androgenetic Alopecia

Androgenetic alopecia (AGA) is characterized by a progressive and patterned transformation of thick, pigmented terminal scalp hairs into short, hypo-pigmented vellus-like hairs. The use of Minoxidil and Finasteride to treat AGA are often associated with complications in safety and efficacy. However, herbal remedies are deemed to have lesser side effects in many societies. This study aims to identify potential hair growth properties of individual compounds from a Chinese proprietary medicine known as Yangxue Shengfa capsule (YSC), used in China for many years for improving AGA. Six marker compounds, including 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), Chlorogenic acid, Emodin, Ferulic acid, Isoimperatorin, and Paeoniflorin were used for simultaneous HPLC quantification and anti-AGA in-vitro screening. Simultaneous quantification of these components was performed on 75% (v/v) methanol extracts of YSC, using a Welch Ultimate XB-C18 column and gradient elution. Five compounds significantly promoted cell proliferation in cultured immortalized human Dermal Papilla Cells (DPC). Multiple genes associated with the progression of AGA, including IGF-1, DKK-1, and TGF-β1, were found to be regulated by some of these compounds. Interestingly, Ferulic acid and Emodin demonstrated good pharmacological properties against AGA, thereby concluding the potential of these bioactives to be used in the treatment against AGA.

Hot water extract of oriental melon leaf promotes hair growth and prolongs anagen hair cycle: In vivo and in vitro evaluation

Effects of hot water extracts of oriental melon leaves (OML) on promotion of hair growth were investigated. Topical OML extract administration for hair regeneration was investigated using an in vivo model with C57BL/6 mice. Effects of OML extracts on the human hair growth were investigated using a hair follicle organ culture. OML extracts induced a shortened telogen to anagen conversion and promoted hair growth in the C57BL/6 mouse model. Culture of human hair follicles in the presence of OML extracts for 8 days promoted hair growth and prolonged the anagen duration due to induction of hair follicle cell proliferation in the bulb region. OML extracts exert a hair growth promotion effect and, therefore, can be used as a therapeutic agent for prevention of hair loss.

Effects of a Closed Space Environment on Gene Expression in Hair Follicles of Astronauts in the International Space Station

Adaptation to the space environment can sometimes pose physiological problems to International Space Station (ISS) astronauts after their return to earth. Therefore, it is important to develop healthcare technologies for astronauts. In this study, we examined the feasibility of using hair follicles, a readily obtained sample, to assess gene expression changes in response to spaceflight adaptation. In order to investigate the gene expression changes in human hair follicles during spaceflight, hair follicles of 10 astronauts were analyzed by microarray and real time qPCR analyses. We found that spaceflight alters human hair follicle gene expression. The degree of changes in gene expression was found to vary among individuals. In some astronauts, genes related to hair growth such as FGF18, ANGPTL7 and COMP were upregulated during flight, suggesting that spaceflight inhibits cell proliferation in hair follicles.

Advances in Understanding Hair Growth

In this short review, I introduce an integrated vision of human hair follicle behavior and describe opposing influences that control hair follicle homeostasis, from morphogenesis to hair cycling. The interdependence and complementary roles of these influences allow us to propose that the hair follicle is a true paradigm of a "Yin Yang" type, that is a cold/slow-hot/fast duality. Moreover, a new promising field is emerging, suggesting that glycans are key elements of hair follicle growth control.

Role of Arachidonic Acid in Promoting Hair Growth

BACKGROUND

Arachidonic acid (AA) is an omega-6 polyunsaturated fatty acid present in all mammalian cell membranes, and involved in the regulation of many cellular processes, including cell survival, angiogenesis, and mitogenesis. The dermal papilla, composed of specialized fibroblasts located in the bulb of the hair follicle, contributes to the control of hair growth and the hair cycle.

OBJECTIVE

This study investigated the effect of AA on hair growth by using in vivo and in vitro models.

METHODS

The effect of AA on human dermal papilla cells (hDPCs) and hair shaft elongation was evaluated by MTT assay and hair follicle organ culture, respectively. The expression of various growth and survival factors in hDPCs were investigated by western blot or immunohistochemistry. The ability of AA to induce and prolong anagen phase in C57BL/6 mice was analyzed.

RESULTS

AA was found to enhance the viability of hDPCs and promote the expression of several factors responsible for hair growth, including fibroblast growth factor-7 (FGF-7) and FGF-10. Western blotting identified the role of AA in the phosphorylation of various transcription factors (ERK, CREB, and AKT) and increased expression of Bcl-2 in hDPCs. In addition, AA significantly promoted hair shaft elongation, with increased proliferation of matrix keratinocytes, during ex vivo hair follicle culture. It was also found to promote hair growth by induction and prolongation of anagen phase in telogen-stage C57BL/6 mice.

CONCLUSION

This study concludes that AA plays a role in promoting hair growth by increasing the expression of growth factors in hDPCs and enhancing follicle proliferation and survival.

The effect of parathyroid hormones on hair follicle physiology: implications for treatment of chemotherapy-induced alopecia

Parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) influence hair follicles through paracrine and intracrine routes. There is significant evidence that PTH and PTHrP influence the proliferation and differentiation of hair follicle cells. The PTH/PTHrP receptor signalling plays an important role in the hair follicle cycle and may induce premature catagen-telogen transition. Transgenic mice with an overexpression or blockade (PTH/PTHrP receptor knockout mice) of PTHrP activity revealed impaired or increased hair growth, respectively. Some findings also suggest that PTHrP may additionally influence the hair cycle by inhibiting angiogenesis. Antagonists of the PTH/PTHrP receptor have been shown to stimulate proliferation of hair follicle cells and hair growth. A hair-stimulating effect of a PTH/PTHrP receptor antagonist applied topically to the skin has been observed in hairless mice, as well as in mice treated with cyclophosphamide. These data indicate that the PTH/PTHrP receptor may serve as a potential target for new (topical) hair growth-stimulating drugs, especially for chemotherapy-induced alopecia.

Platelet-rich Plasma as a Potential Treatment for Noncicatricial Alopecias

Androgenetic alopecia (AGA) and alopecia areata (AA) are common hair loss disorders affecting both men and women. Despite available therapeutic options, search for new, more effective treatment is constant. Platelet-rich plasma (PRP) could be effective in promoting hair growth: (1) To present PRP and its mechanism of action in promoting hair growth and (2) to evaluate its preparation methods and its therapeutic potential in noncicatrial alopecias in a systematic review. An international bibliography search, through five databases, was conducted to find articles regarding PRP's action on hair loss. Growth factors in platelets’ granules of PRP bind in the bulge area of hair follicle, promoting hair growth. In our systematic review, 14 articles matched our criteria, including 12 articles for AGA and two for AA. PRP is a potential useful therapeutic tool for alopecias, without major adverse effects. Nevertheless, due to the small number of conducted trials, further studies are required to investigate its efficacy.

Transcriptome sequencing reveals differences between anagen and telogen secondary hair follicle-derived dermal papilla cells of the Cashmere goat (Capra hircus)

Dermal papilla is considered the control center of hair follicle growth and hair cycle. The secondary hair follicle (producing cashmere) growth cycle of the Cashmere goat (Capra hircus) is circannual, and each growth phase can be easily distinguished by its long duration. To identify gene expression patterns and differences of the dermal papilla cell (DPC) between the anagen and telogen phases, we established two DPC lines: ana-DPCs (DPCs derived from the anagen secondary hair follicle) and tel-DPCs (DPCs derived from the telogen secondary hair follicle). Compared with the ana-DPCs, the tel-DPCs lost the capacity to form cell aggregates and showed lower cell proliferation rate. Transcriptome sequencing revealed that 825 genes were differentially expressed by at least threefold between the two DPC lines. These genes were significantly enriched in cell cycle control, cell division, and chromosome partitioning from the Eukaryotic Orthologous Groups of proteins (KOG) database and in cell cycle, cell adhesion molecules, cytokine-cytokine receptor interaction, and p53 signaling pathway from the Kyoto Encyclopedia of Gene and Genomes (KEGG) database. Enrichment analyses revealed that in the middle of the telogen the DPCs of secondary hair follicles (SHFs) seemed on the one hand to promote the degeneration of SHFs and cessation of cashmere growth, while on the other hand to resist self-apoptosis and prepare for the regeneration or revivification of fully functional dermal papillae. These findings provide a better understanding of hair follicle growth and will be useful for identification of novel molecules associated with the control of hair growth cycle.

Highly upregulated Lhx2 in the Foxn1-/- nude mouse phenotype reflects a dysregulated and expanded epidermal stem cell niche

Hair cycling is a prime example of stem cell dependent tissue regeneration and replenishment, and its regulatory mechanisms remain poorly understood. In the present study, we evaluated the effect of a blockage in terminal keratinocytic lineage differentiation in the Foxn1(-/-) nude phenotype on the epithelial progeny. Most notably we found a constitutive upregulation of LIM homeobox protein 2 (Lhx2), a marker gene of epithelial stem cellness indispensible for hair cycle progression. However, histological evidence along with an erratic, acyclic rise of otherwise suppressed CyclinD1 levels along with several key markers of keratinocyte lineage differentiation indicate a frustrated expansion of epithelial stem cell niches in skin. In addition, CD49f/CD34/CD200-based profiling demonstrated highly significant shifts in subpopulations of epithelial progeny. Intriguingly this appeared to include the expansion of Oct4+ stem cells in dermal fractions of skin isolates in the Foxn1 knock-out opposed to wild type. Overall our findings indicate that the Foxn1(-/-) phenotype has a strong impact on epithelial progeny and thus offers a promising model to study maintenance and regulation of stem cell niches within skin not feasible in other in vitro or in vivo models.

Selected variants of the melanocortin 4 receptor gene (MC4R) do not confer susceptibility to female pattern hair loss

Female pattern hair loss (FPHL) is a common hair loss disorder in women with a complex mode of inheritance. Its etiopathogenesis is poorly understood. Widespread assumptions of overlapping susceptibility variants between FPHL and male pattern baldness (androgenetic alopecia) and a crucial role of androgens or distinct sexual steroid hormones in the development of FPHL could neither be clearly demonstrated nor completely excluded at the molecular level up to date. Interestingly, recent studies suggested an association of metabolic syndrome-including obesity, hyperlipidaemia, hypertension and diabetes mellitus type 2 or abnormally high fasting blood glucose-with FPHL. Of note, mutations in the melanocortin 4 receptor gene (MC4R) have been identified in patients with morbid obesity. Interestingly, this neuropeptide receptor has been detected amongst others in the dermal papilla of the hair follicle. As almost half of our FPHL patients of German origin present with adipositas and/or obesity, we hypothesized as to whether FPHL could be associated with variants of the MC4R gene. Thus, we genotyped a total of six variants from MC4R in our case-control sample comprising 245 UK patients of German and UK origin. However, based on our present study none of the genotyped MC4R variants displayed any significant association, neither in the overall UK and German samples nor in any subgroup analyses. In summary, these results do not point to an involvement of MC4R in FPHL.