Hair Follicle Cycling Research Articles

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

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

Effect of overexpression of KLF4 on the growth and development of hair follicles in mice.

Hair follicle growth is cyclical, and hair cycle dysfunction can lead to hair follicle-related disorders, including alopecia and hirsutism. The objective was to investigate the influence and underlying mechanism of Krüppel-like factor 4 (KLF4) overexpression on hair follicle growth and development in C57BL/6 mice. To provide a theoretical basis for the biological functions of KLF4 gene in hair follicle development and hair follicle cycle, mice were assigned to three groups: experimental, overexpressing KLF4 (Ad-KLF4); control, expressing green fluorescent protein (Ad-NC); and blank, no treatment. Fur was removed from the dorsal surface, and the mice were intradermally injected with 25 μL 1 × 1010 PFU/mL adenovirus vector (Ad-KLF4 or Ad-NC) at three points. Samples were collected for molecular biological and histological analysis. It was found that mRNA and protein levels of Wnt pathway-associated factors β-catenin, LEF1, hair follicle cell proliferation-related factor Ki67, and hair follicle inner caledrin marker AE15 were all significantly greater in the Ad-NC and blank groups than in Ad-KLF4 mice (P < 0.01). These findings were confirmed by immunohistochemical analysis. Hair growth was monitored photographically for 14days, showing an absence of growth in the injected region of the KLF4-overexpressing mice in contrast to non-overexpressing areas where hair growth was normal. HE staining showed that hair follicles in the blank and Ad-NC mice were normal, while those in the KLF4-overexpressing areas remained in telogen or early anagen with spherical dermal papillae situated at the edge of the dermis and subcutaneous tissue without an inner heel sheath. In conclusion, it was found that KLF4 downregulated key Wnt/β-catenin-associated factors during follicular regeneration in mice, reducing both follicular development and growth.

Overview of the Circadian Clock in the Hair Follicle Cycle.

The circadian clock adapts to the light-dark cycle and autonomously generates physiological and metabolic rhythmicity. Its activity depends on the central suprachiasmatic pacemaker. However, it also has an independent function in peripheral tissues such as the liver, adipose tissue, and skin, which integrate environmental signals and energy homeostasis. Hair follicles (HFs) maintain homeostasis through the HF cycle, which depends heavily on HF stem cell self-renewal and the related metabolic reprogramming. Studies have shown that circadian clock dysregulation in HFs perturbs cell cycle progression. Moreover, there is increasing evidence that the circadian clock exerts a significant influence on glucose metabolism, feeding/fasting, stem cell differentiation, and senescence. This suggests that circadian metabolic crosstalk plays an essential role in regulating HF regeneration. An improved understanding of the role of the circadian clock in HFs may facilitate the discovery of new drug targets for hair loss. Therefore, the present review provides a discussion of the relationship between the circadian clock and HF regeneration, mainly from the perspective of HF metabolism, and summarizes the current understanding of the mechanisms by which HFs function.

Molecular Mechanisms Affecting Development of Animal Fibers and Some Studies on Goats

Natural fibers are of two types as vegetable and animal origin. Animal fibers have contributed to the development of the economic structures of the countries and the continuation of their traditions since ancient times and continue to do so. Various studies have shown that the properties of the fiber produced by the hair follicle are of great importance in determining fiber quality and quantity. Hair follicles have been developed in an environment where various molecular signals are effective. In this context, the investigation of molecular mechanisms affecting hair follicle development has come into prominence and it is seen that it has become the focus of studies. In this review, it has been tried to explain the importance of animal fibers and the molecular mechanisms affecting hair follicle morphogenesis and cycle by providing some examples from the studies on two goat breeds, Angora goat and cashmere goat, which are valuable in terms of animal fiber, leading to provide a preliminary information to the studies which has become the focus of today.

The Progress of Common Treatments and Research for Androgenetic Alopecia

Androgenetic alopecia (AGA) is the most common type of hair loss, in which patients mostly present with a state of a receding hairline on the forehead. It brings a great mental burden to the patient. Androgenetic alopecia is caused by the combination of dihydrotestosterone (DHT) and androgen receptors (AR), disrupting the hair follicle cycle and minimizing hair follicles. The major treatments currently available include finasteride, minoxidil, hair transplantation, Platelet-rich plasma (PRP), stem cell therapy, etc. This article reviews the mechanism of AGA and the existing major treatments. The author suggested that androgen receptor degrader drugs have good prospects for application among those of various therapeutic options.

IPSC-based approach for human hair follicle regeneration.

Hair follicles (HFs) are a multifunctional structure involved in physical protection, thermoregulation, sensational detection, and wound healing. Formation and cycling of HFs require dynamic interaction between different cell types of the follicles. Although the processes have been well studied, the generation of human functional HFs with a normal cycling pattern for clinical utilization has yet to be achieved. Recently, human pluripotent stem cells (hPSCs) serve as an unlimited cell source for generating various types of cells including cells of the HFs. In this review, HF morphogenesis and cycling, different cell sources used for HF regeneration, and potential strategies for HF bioengineering using induced pluripotent stem cells (iPSCs) are depicted. Challenges and perspectives toward the therapeutic use of bioengineered HFs for hair loss disorder are also discussed.

Transcriptome analysis reveals genes associated with wool fineness in merinos.

Hair/wool usually plays an important role in maintaining animal physiological activities, and the economic value of wool cannot be ignored. At present, people set higher demands on wool fineness. Hence, improving wool fineness is the concern of fine wool sheep breeding. Using RNA-Seq to screen the potential candidate genes that associate with wool fineness can provide theoretical references for fine-wool sheep breeding, and also provide us new ideas for further understand the molecular regulation mechanism of hair growth. In this study, we compared the expression pattern difference of genome-wide genes between the skin transcriptomes of Subo and Chinese Merinos. The results showed that, 16 candidate differentially expressed genes (DEGs) (Included: CACNA1S, GP5, LOC101102392, HSF5, SLITRK2, LOC101104661, CREB3L4, COL1A1, PTPRR, SFRP4, LOC443220, COL6A6, COL6A5, LAMA1, LOC114115342 and LOC101116863 genes) that may associate with wool fineness were screened, and these genes were located in signaling pathways that regulate hair follicle development, cycle or hair growth. It is worth noting that, among the 16 DEGs, COL1A1 gene has the highest expression level in Merino skins, and the fold change of LOC101116863 gene is the highest, and the structures of these two genes are both highly conserved in different species. In conclusion, we speculate that these two genes may play a key role in regulating wool fineness and respectively have similar and conserved functions in different species.

Regulatory Effects of FGF9 on Dermal Papilla Cell Proliferation in Small-Tailed Han Sheep.

Fibroblast growth factor 9 (FGF9) is crucial for the growth and development of hair follicles (HFs); however, its role in sheep wool growth is unknown. Here, we clarified the role of FGF9 in HF growth in the small-tailed Han sheep by quantifying FGF9 expression in skin tissue sections collected at different periods. Moreover, we evaluated the effects of FGF9 protein supplementation on hair shaft growth in vitro and FGF9 knockdown on cultured dermal papilla cells (DPCs). The relationship between FGF9 and the Wnt/β-catenin signaling pathway was examined, and the underlying mechanisms of FGF9-mediated DPC proliferation were investigated. The results show that FGF9 expression varies throughout the HF cycle and participates in wool growth. The proliferation rate and cell cycle of FGF9-treated DPCs substantially increase compared to that of the control group, and the mRNA and protein expression of CTNNB1, a Wnt/β-catenin signaling pathway marker gene, is considerably lower than that in the control group. The opposite occurs in FGF9-knockdown DPCs. Moreover, other signaling pathways are enriched in the FGF9-treated group. In conclusion, FGF9 accelerates the proliferation and cell cycle of DPCs and may regulate HF growth and development through the Wnt/β-catenin signaling pathway.

1381 Investigating the role of Mef2c in hair follicle cycling

1381 Investigating the role of Mef2c in hair follicle cycling

1433 Epithelially derived, mitochondrial MPZL3 negatively regulates murine and human hair follicle cycling

1433 Epithelially derived, mitochondrial MPZL3 negatively regulates murine and human hair follicle cycling

The Efficacy and Safety of Dr. SKS Hair Booster Serum (a Cocktail of Micronutrients and Multivitamins) in Adult Males and Females With Androgenetic Alopecia: An Open-Label, Non-randomized, Prospective Study.

Background Androgenetic alopecia (AGA) is frequently encountered in dermatological practice; however, there is a lack of approved treatment. At present, only three therapies have been approved for on-label use in androgenetic alopecia: minoxidil, finasteride, and lower-level laser therapy. Micronutrients are primary elements in the normal hair follicle cycle, and their role in androgenetic alopecia is a growing matter of research nowadays. This study aims to investigate the clinical efficacy and safety of Dr. SKS Hair Booster Serum, a cocktail of micronutrients and multivitamins (copper, niacinamide, hyaluronic acid, thiamine, riboflavin, and biotin), in male and female patients with androgenetic alopecia. Methods We did an open-label, non-randomized, multicenter, prospective study across five hair clinic chains in India (Mumbai, Hyderabad, Jabalpur, Balaghat, and Nagpur). Eligible participants were patients with a confirmed diagnosis of androgenetic alopecia based on clinical examination and trichoscopic findings, age of 18 years or older, and any gender. Each patient received Dr. SKS Hair Booster Serum, 1 ml in volume, once a month by mesotherapy or derma roller/derma pen for up to six months. All patients were subjected to a 60-second hair counttest (comb test), hair pulltest, global photographic assessment (GPA), trichoscopy assessment, patient self-assessment questionnaire, and safety assessment at baseline and six months after the treatment. Results One thousand patients (500 males and females each) with androgenetic alopecia were analyzed. There was a significant reduction in hair fall with bulb (<0.0001) and without bulb (<0.0001) six months after the treatment versus baseline. There was a significant improvement in the number of hairs removed per pull (<0.0001), global photographic assessment score (<0.0001), hair growth rate (<0.0001), follicular hair density (<0.0001), vellus hair density (<0.0001), and terminal hair density (<0.0001) six months after the treatment versus baseline. The majority of patients (95%) were satisfied with six-monthtreatment of Dr. SKS Hair Booster Serum. No major adverse events were reported during the study. Conclusion Dr. SKS Hair Booster Serum was found to be a safe and effective treatment for androgenetic alopecia, with 95% patient self-assessment score.

MiR-21 regulated hair follicle cycle development in Cashmere goats by targeting FGF18 and SMAD7

Increasing Cashmere production can add value because it is the primary product of Cashmere goats. Recent years, peoples find miRNAs are crucial in regulating the development of hair follicle. Following Solexa sequencing, many miRNAs were distinguishingly expressed in telogen skin samples of goats and sheep in earlier study. But the method through which miR-21 controls the growth of hair follicles is still ambiguous. Bioinformatics analysis was used to predict the target genes of miR-21. The mRNA level of miR-21 in telogen Cashmere goat skins was higher than in anagen, according to the results of qRT-PCR, and the target genes expressed similarly with miR-21. Western blot showed similar trend, the protein expression of FGF18 and SMAD7 were lower in anagen samples. The Dual-Luciferase reporter assay confirmed miRNA-21's relationship with its target gene, and the consequences indicated found FGF18 and SMAD7 have positive correlations with miR-21. Western blot and qRT-PCR distinguished the expression of protein and mRNA in miR-21 and its target genes. According to the consequence, we found that target genes expression was increased by miR-21 in HaCaT cells. This study identified that miR-21 might take part in the development of Cashmere goat’s hair follicles by targeting FGF18 and SMAD7.

Extraction of Gallic Acid and Ferulic Acid for Application in Hair Supplements

Food supplements based on antioxidants and vitamins are often prescribed to correct inefficiencies in the human diet and delay diseases such as premature aging and alopecia (temporary or permanent hair loss), given the free radical scavenging activity of these biomolecules. By reducing the concentration of reactive oxygen species (ROS), which promote abnormal hair follicle cycling and morphology, follicle inflammation and oxidative stress are reduced, minimising the effects of these health issues. Gallic acid (GA), which is significantly present in gallnuts and in pomegranate root bark, and ferulic acid (FA), commonly found in brown rice and coffee seeds, are very important antioxidants for the preservation of hair colour, strength and growth. In this work, these two secondary phenolic metabolites were successfully extracted in the Aqueous Two-Phase Systems (ATPS) {ethyl lactate (1) + trisodium citrate (2) + water (3)} and {ethyl lactate (1) + tripotassium citrate (2) + water (3)} at 298.15 K and 0.1 MPa, moving towards the application of these ternary systems in extracting antioxidants from biowaste and their a posteriori processing as food supplements for hair fortification. The studied ATPS provided biocompatible and sustainable media for the extraction of gallic acid and ferulic acid, yielding low mass losses (<3%) and contributing to an eco-friendlier production of therapeutics. The most promising results were obtained for ferulic acid, which attained maximum partition coefficients (K) of 15 ± 5 and (3 ± 2) · 101 and maximum extraction efficiencies (E) of (92.7 ± 0.4)% and (96.7 ± 0.4)% for the longest tie-lines (TLL = 69.68 and 77.66 m%) in {ethyl lactate (1) + trisodium citrate (2) + water (3)} and {ethyl lactate (1) + tripotassium citrate (2) + water (3)}, respectively. Moreover, the effect of pH on the UV-Vis absorbance spectra was studied for all the biomolecules to minimise errors in solute quantification. Both GA and FA were found to be stable at the used extractive conditions.

Regulation of epidermal proliferation and hair follicle cycling by synthetic photostable retinoid EC23.

Retinoid signaling is an important regulator of the epidermis and skin appendages. Therefore, synthetic retinoids have been developed for therapeutic use for skin disorders such as psoriasis and acne. In previous studies, we showed how the photostable retinoid EC23 induces neuronal differentiation in stem cell-like cell populations, and here, we aim to investigate its ability to influence epidermal and hair follicle growth. EC23 influence on skin biology was investigated initially in cultures of monolayer keratinocytes and three-dimentional in vitro models of skin, and finally in in vivo studies of mice back skin. EC23 induces keratinocyte hyperproliferation in vitro and in vivo, and when applied to mouse skin increases the number of involucrin-positive suprabasal cell layers. These phenotypic changes are similar in skin treated with the natural retinoid all-trans retinoic acid (ATRA); however, EC23 is more potent; a tenfold lower dose of EC23 is sufficient to induce epidermal thickening, and resulting hyperproliferation is sustained for a longer time period after first dose. EC23 treatment resulted in a disorganized stratum corneum, reduced cell surface lipids and compromised barrier, similar to ATRA treatment. However, EC23 induces a rapid telogen to anagen transition and hair re-growth in 6-week-old mice with synchronously resting back skin follicles. The impact of EC23 on the hair cycle was surprising as similar results have not been seen with ATRA. These data suggest that synthetic retinoid EC23 is a useful tool in exploring the turnover and differentiation of cells and has a potent effect on skin physiology.

Anagen hair follicles transplanted into mature human scars remodel fibrotic tissue

Despite the substantial impact of skin scarring on patients and the healthcare system, there is a lack of strategies to prevent scar formation, let alone methods to remodel mature scars. Here, we took a unique approach inspired by how healthy hairbearing skin undergoes physiological remodelling during the regular cycling of hair follicles. In this pilot clinical study, we tested if hair follicles transplanted into human scars can facilitate tissue regeneration and actively remodel fibrotic tissue, similar to how they remodel the healthy skin. We collected full-thickness skin biopsies and compared the morphology and transcriptional signature of fibrotic tissue before and after transplantation. We found that hair follicle tranplantation induced an increase in the epidermal thickness, interdigitation of the epidermal-dermal junction, dermal cell density, and blood vessel density. Remodelling of collagen type I fibres reduced the total collagen fraction, the proportion of thick fibres, and their alignment. Consistent with these morphological changes, we found a shift in the cytokine milieu of scars with a long-lasting inhibition of pro-fibrotic factors TGFβ1, IL13, and IL-6. Our results show that anagen hair follicles can attenuate the fibrotic phenotype, providing new insights for developing regenerative approaches to remodel mature scars.

Regulation of secondary hair follicle cycle in cashmere goats by miR-877-3p targeting IGFBP5 gene.

Cashmere, a highly valuable animal product derived from cashmere goats, holds significant economic importance. MiRNAs serve as crucial regulators in the developmental processes of mammalian hair follicles. Understanding the regulation of miRNAs during the hair follicle cycle is essential for enhancing cashmere quality. In this investigation, we employed high-throughput sequencing technology to analyze the expression profiles of miRNAs in the secondary hair follicles of Jiangnan cashmere goats at different stages. Through bioinformatics analysis, we identified differentially expressed miRNAs (DE miRNAs). The regulatory relationships between miRNAs and their target genes were verified using multiple techniques, including RT-qPCR, western blot, Dual-Luciferase Reporter, and CKK-8 assays. Our findings revealed the presence of 193 DE miRNAs during various stages of the hair follicle cycle in Jiangnan cashmere goats. Based on the previously obtained mRNA data, the target genes of DE miRNA were predicted, and 1,472 negative regulatory relationships between DE miRNAs and target genes were obtained. Notably, the expression of chi-miR-877-3p was down-regulated during the telogen (Tn) phase compared to the anagen (An) and catagen (Cn) phases, while the IGFBP5 gene exhibited up-regulation. Further validation experiments confirmed that overexpression of chi-miR-877-3p in dermal papilla cells suppressed IGFBP5 gene expression and facilitated cell proliferation. The results of this study provide novel insights for analyzing the hair follicle cycle.

Hair Regrowth with Novel Hemp Extract: A Case Series.

The endocannabinoid system (ECS), discovered in the 1990s, is a system involved with maintaining cellular homeostasis by down-regulating the damaging inflammatory responses and upregulating regenerative processes. Cannabidiol (CBD), tetrahydrocannabivarin (THCV), and cannabidivarin (CBDV) are all phytocannabinoids found in varying quantities in hemp extract. These three cannabinoids have novel therapeutic effects on hair regrowth through the ECS. The method of action is different from and synergistic with current hair regrowth therapies. The three cannabinoids are fat-soluble and poorly absorbed past the epidermis, but topical application easily reaches hair follicles where they act as partial or full CB1 antagonist and agonist of transient receptor potential vanilloid-1 (TRPV1) and vanilloid receptor-4 (TRPV4). All these ECS receptors relate to hair follicle function. Blocking the CB1 receptor on the hair follicle has been shown to result in hair shaft elongation; in addition, the hair follicle cycle (anagen, catagen, and telogen phases) is controlled by TRPV1. The effects of CBD on hair growth are dose dependent and higher doses may result in premature entry into the catagen phase through a different receptor known as TRPV4. CBD has also been shown to increase Wnt signaling, which causes dermal progenitor cells to differentiate into new hair follicles and maintains anagen phase of the hair cycle. This study was conducted on subjects with androgenetic alopecia (AGA), as follow-up to a prior published study using hemp extract high in CBD without CBDV or THCV. That study showed an average 93.5% increase in hair numbers after 6 months of use. This subsequent study is being done to determine if daily topical application of a hemp-oil high in CBD, THCV, and CBDV concentrations would result in improved hair regrowth in the area of the scalp most affected by AGA. A case series study was done of 31 (15 men and 16 women, 27 Caucasian, 2 Asian, and 1 mixed race) subjects with AGA. They used a once-daily topical hemp extract formulation, averaging about 33 mg/day for 6 months. A hair count of the greatest area of alopecia was carried out before treatment was started and again after 6 months of treatment. To facilitate consistent hair count analysis, a permanent tattoo was placed at the point for maximum hair loss on the scalp. The subjects were also asked to qualitatively rate their psychosocial perception of "scalp coverage" improvement after the study was completed. The qualitative scale included "very unhappy," "unhappy," "neutral," "happy," and "very happy." The subjects were photographed in a standard manner before and after the study. The photographs were compared for improvements in "scalp coverage" by an independent physician. The qualitative scale included "none," "mild," "moderate," and "extensive" improvement of scalp coverage. The results revealed that all subjects had some regrowth. This ranged from 31.25% (from 16 to 21 hairs) to 2000% (from 1 to 21 hairs). The average increase was statistically significant 246% (15.07 hairs/cm2 increase) in men and 127% (16.06 hairs/cm2) in women. There were no reported adverse effects. All subjects rated their psychosocial perception of the effects of the hair loss, as "happy" or "very happy." Independent review of the photographs revealed evidence of "mild" to "extensive" scalp coverage improvements for all of the subjects. Although the exact mechanism of therapeutic effects is not known, THCV and CBDV are most likely functioning as full CB1 receptor neutral antagonists and CBD is most likely functioning as a partial CB1 receptor antagonist and potentially through Wnt messaging. All three cannabinoids were functioning as TRPV1 agonists. The addition of menthol through the peppermint extract is probably acting through promoting a rapid onset of anagen phase. This topical hemp formulation was superior to oral finasteride, 5% minoxidil once daily foam and CBD topical extract alone. Since this hemp extract works through novel mechanisms entirely different from both finasteride and minoxidil, it can be used in conjunction with these current drugs and would be expected to have synergistic effects. However, safety and efficacy of this combination would be to be evaluated.

A study to assess the relationship between female pattern hair loss and levels of serum 25 Hydroxyvitamin D and ferritin

Background: Female Pattern Hair Loss [FPHL] is the most common cause of diffuse hair loss in women. It is a result of altered hair follicle cycling and miniaturization, which leads to the transformation of terminal to villous hair follicles and the production of shorter finer hair shafts. The pathophysiology of FPHL is not well understood and it is likely to be a multifactorial genetic trait. Unlike in men, an androgen-dependent nature has not been proven in FPHL. Serum levels of vitamin D and Ferritin are factors recently considered in approaching patients with hair loss complaints. Methods: A case control study with 30 FPHL cases and equal number of healthy controls was conducted among female patients between 17 and 50 years of age. Serum levels of 25 hydroxy vitamin D and Ferritin were measured and compared with the stage of the disease and other parameters. Results: The serum ferritin values of the FPHL cases [17.02 +/- 16.07 ng/ml] were significantly lower than that of the controls [49.40 +/- 27ng/ml; p=0.001]. The serum 25 hydroxy vitamin D level in FPHL cases [15.98 +/- 7.33 ng/ml] were also significantly lower than that of controls [32.89 +/- 20.63ng/ml; p=0.001]. While comparing the serum ferritin with Ludwig’s grading, a statistically significant difference between the grades of the disease was found with the lowest value in stage 1 disease. No statistically significant difference was found when grade of disease was compared with vitamin D status, although vitamin D status decreased with severity of the disease. Conclusions: The levels of serum 25 hydroxy vitamin d and serum ferritin are decreased in patients with female pattern hair loss and the altered levels of these could be a risk factor for the development of the disease.

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

BackgroundAs the direct organ of villus, hair follicles have obvious seasonal cycles. The hair follicle cycle is orchestrated by multiple cell types that together direct cell renewal and differentiation. But the regulation property of hair follicle cells from anagen to catagen in yak is still unknown.ResultsIn this study, single-cell RNA sequencing was performed on 24,124 single cells of the scapular skin from white yak. Based on tSNE cluster analysis, the cell types of IFE-DC, epidermal cell lines, fibroblasts, keratinocytes, IRS, DS, INFU, and other cells in yak hair follicles during anagen and catagen were successfully identified, and the gene expression profiles were described. The GO enrichment analysis indicated the different cells characteristic genes to be mainly enriched in the epidermal development, epithelial cell differentiation and wound healing pathways. The pseudotime trajectory analysis described the differentiation trajectory of the epidermal lineage and dermal lineage of the hair follicle during anagen and catagen. Moreover, the dynamic changes of the genes like LHX2, KRT25, and KRT71 were found to be highly expressed in HS and IRS, but not in the IFE-DC, INFU, and keratinocyte during differentiation.ConclusionsOur results analyzed the time-varying process of gene expression in the dermal cell lineage and epidermal cell lineage of hair follicles during anagen and catagen during fate differentiation was expounded at the single cell level, revealing the law of fate specialization of different types of cells. In addition, based on the enrichment analysis, the transcriptional regulatory factors involved in the different cell fates were also revealed. These results will help to enhance our understanding of yak hair follicle cycle and promote the development and utilization of yak villus.

A catena between psychiatric disorders and non-scarring alopecias-A systematic review.

For many years, clinical observations have suggested that there is an intrinsic connection between psychological state and skin diseases. Stress responses are typically mediated by several hormones, which are modulated via the hypothalamic-pituitary-adrenal axis. This typical stress response is not only one theory for psychiatry disorder pathophysiology, but it also modifies hair growth by altering the skin's inflammatory environment. Given that different forms of hair loss, such as androgenetic alopecia, alopecia areata, or telogen effluvium, and hair follicle cycling can be altered by immune cells within the follicle milieu, we hypothesized that specific forms of hair loss are correlated to psychiatric illnesses. To address this, we conducted a systematic review by searches in April and May 2021 through Ovid MEDLINE and PUBMED (ranging from 1951 to the present day), identifying 179 reports. A further 24 reports were identified through website and citation searches giving a total of 201 reports. After applying exclusion criteria, 21 papers were reviewed, and 17 were included for data analysis. It is undeniable that hair loss greatly affects Health-related Quality of Life (HrQol) and it is heavily associated with major depressive disorder and anxiety. The correlation between hair loss and mental health disorders was significant, however, due to the low number of publications with quantitative data we were not able to identify correlations between each hair loss type with each psychiatric disorder. Further studies to better connect specific hair loss diseases to specific disorders are therefore critical in bettering the way both psychiatric disease, and hair loss, are managed.