Endogenous retinoids in the hair follicle and sebaceous gland

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

BACKGROUND

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.

AIMS

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Topical Delivery of Atraric Acid Derived from Stereocaulon japonicum with Enhanced Skin Permeation and Hair Regrowth Activity for Androgenic Alopecia

Atraric acid (AA) is a phenolic compound isolated from Stereocaulon japonicum that has demonstrated anti-androgen properties and was used to design an alternative formulation for the treatment of alopecia. This new topical formulation was designed using a solvent mixture system composed of ethanol as a volatile vehicle, oleic acid as a permeation enhancer, and water for skin hydration. The ideal topical AA formulation (AA-TF#15) exhibited an 8.77-fold higher human skin flux and a 570% increase in dermal drug deposition, compared to 1% (w/w) AA in ethanol. In addition, compared to other formulations, AA-TF#15 (1% [w/w] AA) activated keratinocytes and human dermal papilla cell proliferation at a concentration of 50 µM AA, which is equivalent to 50 µM minoxidil. Moreover, AA-TF#15 treatment produced a significant increase in hair regrowth by 58.0% and 41.9% compared to the 1% (w/w) minoxidil and oral finasteride (1 mg/kg)-treated mice. In addition, AA-TF#15 showed a higher expression level of aldehyde dehydrogenase 1, β-catenin, cyclin D1, and pyruvate kinase M2 proteins in the skin of AA-TF#15-treated mice compared to that of those treated with minoxidil and oral finasteride. These findings suggest AA-TF#15 is an effective formulation for the treatment of scalp androgenic alopecia.

UV and visible light exposure to hair leads to widespread changes in the hair lipidome

OBJECTIVE

Scalp hair is among the most exposed parts of the human body, yet the impact of visible and UV light on hair lipids, an important structural component of hair, is poorly researched. We have used lipidomics, a broad-based approach to measure lipids in samples, which has hitherto not been applied to UV-exposed hair in the published literature, and could allow for a wider understanding of how UV light impacts on specific hair lipids.

METHODS

Mixed blonde Caucasian hair switches were divided into two groups of five, with half of the hair switches exposed to UV and visible light mimicking normal daytime exposure and half left unexposed. LC-MS lipidomics was used to profile the lipids in the hair samples.

RESULTS

A total of 791 lipids and 32 lipid classes with tentative identifications were detected in the hair samples. Nineteen lipid classes and 397 lipids differed between UV-treated and non-treated hair. The main lipid classes that differed were vitamin A fatty acid esters, sterol esters, several ceramides, mono-, di- and triglycerides, phosphatidylethanolamines (all decreased in UV-exposed hair) and bismonoacylglycerolphosphates, acylcarnitines and acylglycines (all increased in UV-exposed hair). Most detected lipids were decreased in UV-exposed hair, supporting earlier work that has found that UV exposure causes oxidation of lipids which would result in a decrease in most lipid classes.

CONCLUSION

Light exposure to hair has a widespread impact on the hair lipidome. This study also adds to the emerging literature on the hair lipidome, broadening the range of lipid classes reported in hair.

An overview of the genetic aspects of hair loss and its connection with nutrition

Hair loss is a widespread concern in dermatology clinics, affecting both men's and women's quality of life. Hair loss can have many different causes, which are critical to identify in order to provide appropriate treatment. Hair loss can happen due to many variables, such as genetic factors or predisposition, vitamin and mineral deficiencies, skin problems, hair growth disorders, poor diet, hormonal problems, certain internal diseases, drug use, stress and depression, cosmetic factors, childbirth, and the chemotherapy process. Treatment for hair loss varies depending on the type of alopecia, deficiency, or excess of structures such as vitamins and minerals, and also on hair and skin structure. The Mediterranean diet is characterized by low amounts of saturated fat, animal protein, and high amounts of unsaturated fat, fiber, polyphenols, and antioxidants. The main nutrients found in the Mediterranean Diet are rich in antioxidant, anti-inflammatory components. It also has an important place in hair loss treatment, since recently treatment strategies have included polyphenols and unsaturated oils more and more frequently. The goal of this work was to review published articles examining alopecia and its types, the many micronutrients that affect alopecia, and the role of the Mediterranean diet in alopecia. The literature shows that little is known about hair loss, nutritional factors, and diet, and that the data collected are conflicting. Given these differences, research into the function of diet and nutrition in the treatment of baldness is a dynamic and growing topic.

Transcriptome Analysis of Particulate Matter 2.5-Induced Abnormal Effects on Human Sebocytes

Particulate matter 2.5 (PM2.5), an atmospheric pollutant with an aerodynamic diameter of <2.5 μm, can cause serious human health problems, including skin damage. Since sebocytes are involved in the regulation of skin homeostasis, it is necessary to study the effects of PM2.5 on sebocytes. We examined the role of PM2.5 via the identification of differentially expressed genes, functional enrichment and canonical pathway analysis, upstream regulator analysis, and disease and biological function analysis through mRNA sequencing. Xenobiotic and lipid metabolism, inflammation, oxidative stress, and cell barrier damage-related pathways were enriched; additionally, PM2.5 altered steroid hormone biosynthesis and retinol metabolism-related pathways. Consequently, PM2.5 increased lipid synthesis, lipid peroxidation, inflammatory cytokine expression, and oxidative stress and altered the lipid composition and expression of factors that affect cell barriers. Furthermore, PM2.5 altered the activity of sterol regulatory element binding proteins, mitogen-activated protein kinases, transforming growth factor beta-SMAD, and forkhead box O3-mediated pathways. We also suggest that the alterations in retinol and estrogen metabolism by PM2.5 are related to the damage. These results were validated using the HairSkin® model. Thus, our results provide evidence of the harmful effects of PM2.5 on sebocytes as well as new targets for alleviating the skin damage it causes.

Vitamin A in Skin and Hair: An Update

Vitamin A is a fat-soluble micronutrient necessary for the growth of healthy skin and hair. However, both too little and too much vitamin A has deleterious effects. Retinoic acid and retinal are the main active metabolites of vitamin A. Retinoic acid dose-dependently regulates hair follicle stem cells, influencing the functioning of the hair cycle, wound healing, and melanocyte stem cells. Retinoic acid also influences melanocyte differentiation and proliferation in a dose-dependent and temporal manner. Levels of retinoids decline when exposed to ultraviolet irradiation in the skin. Retinal is necessary for the phototransduction cascade that initiates melanogenesis but the source of that retinal is currently unknown. This review discusses new research on retinoids and their effects on the skin and hair.

Natural Antioxidants from Plant Extracts in Skincare Cosmetics: Recent Applications, Challenges and Perspectives

In recent years, interest in the health effects of natural antioxidants has increased due to their safety and applicability in cosmetic formulation. Nevertheless, efficacy of natural antioxidants in vivo is less documented than their prooxidant properties in vivo. Plant extracts rich in vitamins, flavonoids, and phenolic compounds can induce oxidative damage by reacting with various biomolecules while also providing antioxidant properties. Because the biological activities of natural antioxidants differ, their effectiveness for slowing the aging process remains unclear. This review article focuses on the use of natural antioxidants in skincare and the possible mechanisms underlying their desired effect, along with recent applications in skincare formulation and their limitations.

Retinaldehyde Dehydrogenase Inhibition-Related Adverse Outcome Pathway: Potential Risk of Retinoic Acid Synthesis Inhibition during Embryogenesis

Retinoic acid (RA) is one of the factors crucial for cell growth, differentiation, and embryogenesis; it interacts with the retinoic acid receptor and retinoic acid X receptor to eventually regulate target gene expression in chordates. RA is transformed from retinaldehyde via oxidization by retinaldehyde dehydrogenase (RALDH), which belongs to the family of oxidoreductases. Several chemicals, including disulphiram, diethylaminobenzaldehyde, and SB-210661, can effectively inhibit RALDH activity, potentially causing reproductive and developmental toxicity. The modes of action can be sequentially explained based on the molecular initiating event toward key events, and finally the adverse outcomes. Adverse outcome pathway (AOP) is a conceptual and theoretical framework that describes the sequential chain of casually liked events at different biological levels from molecular events to adverse effects. In the present review, we discussed a recently registered AOP (AOP₂₉₇; inhibition of retinaldehyde dehydrogenase leads to population decline) to explain and support the weight of evidence for RALDH inhibition-related developmental toxicity using the existing knowledge.

Estrogen regulates the expression of retinoic acid synthesis enzymes and binding proteins in mouse skin

Topical 17-beta-estradiol (E2) regulates the hair cycle, hair shaft differentiation, and sebum production. Vitamin A also regulates sebum production. Vitamin A metabolism proteins localized to the pilosebaceous unit (PSU; hair follicle and sebaceous gland); and were regulated by E2 in other tissues. This study tests the hypothesis that E2 also regulates vitamin A metabolism in the PSU. First, aromatase and estrogen receptors localized to similar sites as retinoid metabolism proteins during mid-anagen. Next, female and male wax stripped C57BL/6J mice were topically treated with E2, the estrogen receptor antagonist ICI 182,780 (ICI), letrozole, E2 plus letrozole, or vehicle control (acetone) during mid-anagen. E2 or one of its inhibitors regulated most of the vitamin A metabolism genes and proteins examined in a sex-dependent manner. Most components were higher in females and reduced with ICI in females. ICI reductions occurred in the premedulla, sebaceous gland, and epidermis. Reduced E2 also reduced RA receptors in the sebaceous gland and bulge in females. However, reduced E2 increased the number of retinal dehydrogenase 2 positive hair follicle associated dermal dendritic cells in males. These results suggest that estrogen regulates vitamin A metabolism in the skin. Interactions between E2 and vitamin A have implications in acne treatment, hair loss, and skin immunity.

Detecting the Mechanism behind the Transition from Fixed Two-Dimensional Patterned Sika Deer (Cervus nippon) Dermal Papilla Cells to Three-Dimensional Pattern

The hair follicle dermal papilla is critical for hair generation and de novo regeneration. When cultured in vitro, dermal papilla cells from different species demonstrate two distinguishable growth patterns under the conventional culture condition: a self-aggregative three dimensional spheroidal (3D) cell pattern and a two dimensional (2D) monolayer cell pattern, correlating with different hair inducing properties. Whether the loss of self-aggregative behavior relates to species-specific differences or the improper culture condition remains unclear. Can the fixed 2D patterned dermal papilla cells recover the self-aggregative behavior and 3D pattern also remains undetected. Here, we successfully constructed the two growth patterns using sika deer (Cervus nippon) dermal papilla cells and proved it was the culture condition that determined the dermal papilla growth pattern. The two growth patterns could transit mutually as the culture condition was exchanged. The fixed 2D patterned sika deer dermal papilla cells could recover the self-aggregative behavior and transit back to 3D pattern, accompanied by the restoration of hair inducing capability when the culture condition was changed. In addition, the global gene expressions during the transition from 2D pattern to 3D pattern were compared to detect the potential regulating genes and pathways involved in the recovery of 3D pattern and hair inducing capability.

Trifarotene: A Current Review and Perspectives in Dermatology

Retinoids have numerous applications in inflammatory, dyskeratotic, and oncohematology diseases. Retinoids have now reached the fourth generation, progressively reducing toxicity whilst increasing their efficacy. Trifarotene is a new fourth-generation retinoid with a selective action on RAR-γ. In this review, we reported the trials—both concluded and in progress—including the use of trifarotene in dermatological diseases. Studies were identified by searching electronic databases (MEDLINE, EMBASE, PubMed, Cochrane, Trials.gov) from 2012 to today and reference lists of respective articles. Only articles published in English language were included. Randomized trials evaluating trifarotene tolerability, safety, and efficacy in congenital ichthyosis and acne have demonstrated great results and mild side effects, leading to the approval by the FDA of trifarotene for the treatment of lamellar ichthyosis in 2014, and of acne vulgaris in October 2019. No high-quality randomized clinical trials have evaluated the treatment of primary cutaneous lymphomas with trifarotene. Finally, we are hypothesizing future perspectives in the treatment of non-melanoma skin cancers, fungal infections, photoaging, and hand-foot skin reactions with trifarotene.

Dietary Vitamin A Impacts Refractory Telogen

Hair follicles cycle through periods of growth (anagen), regression (catagen), rest (telogen), and release (exogen). Telogen is further divided into refractory and competent telogen based on expression of bone morphogenetic protein 4 (BMP4) and wingless-related MMTV integration site 7A (WNT7A). During refractory telogen hair follicle stem cells (HFSC) are inhibited. Retinoic acid synthesis proteins localized to the hair follicle and this localization pattern changed throughout the hair cycle. In addition, excess retinyl esters arrested hair follicles in telogen. The purpose of this study was to further define these hair cycle changes. BMP4 and WNT7A expression was also used to distinguish refractory from competent telogen in C57BL/6J mice fed different levels of retinyl esters from two previous studies. These two studies produced opposite results; and differed in the amount of retinyl esters the dams consumed and the age of the mice when the different diet began. There were a greater percentage of hair follicles in refractory telogen both when mice were bred on an unpurified diet containing copious levels of retinyl esters (study 1) and consumed excess levels of retinyl esters starting at 12 weeks of age, as well as when mice were bred on a purified diet containing adequate levels of retinyl esters (study 2) and remained on this diet at 6 weeks of age. WNT7A expression was consistent with these results. Next, the localization of vitamin A metabolism proteins in the two stages of telogen was examined. Keratin 6 (KRT6) and cellular retinoic acid binding protein 2 (CRABP2) localized almost exclusively to refractory telogen hair follicles in study 1. However, KRT6 and CRABP2 localized to both competent and refractory telogen hair follicles in mice fed adequate and high levels of retinyl esters in study 2. In mice bred and fed an unpurified diet retinol dehydrogenase SDR16C5, retinal dehydrogenase 2 (ALDH1A2), and cytochrome p450 26B1 (CYP26B1), enzymes and proteins involved in RA metabolism, localized to BMP4 positive refractory telogen hair follicles. This suggests that vitamin A may contribute to the inhibition of HFSC during refractory telogen in a dose dependent manner.

Retinoids in Cutaneous Squamous Cell Carcinoma

Animal studies as early as the 1920s suggested that vitamin A deficiency leads to squamous cell metaplasia in numerous epithelial tissues including the skin. However, humans usually die from vitamin A deficiency before cancers have time to develop. A recent long-term cohort study found that high dietary vitamin A reduced the risk of cutaneous squamous cell carcinoma (cSCC). cSCC is a form of nonmelanoma skin cancer that primarily occurs from excess exposure to ultraviolet light B (UVB). These cancers are expensive to treat and can lead to metastasis and death. Oral synthetic retinoids prevent the reoccurrence of cSCC, but side effects limit their use in chemoprevention. Several proteins involved in vitamin A metabolism and signaling are altered in cSCC, which may lead to retinoid resistance. The expression of vitamin A metabolism proteins may also have prognostic value. This article reviews what is known about natural and synthetic retinoids and their metabolism in cSCC.

A Systemic Review on Topical Marketed Formulations, Natural Products, and Oral Supplements to Prevent Androgenic Alopecia: A Review

Androgens have an intense consequence on the human scalp and body hair. Scalp hair sprouts fundamentally in awol of androgens whereas the body hair hike is vulnerable to the activity of androgens. Androgenetic alopecia (AGA) invoked as males emulate Alopecia due to the cause of the dynamic reduction of scalp hair. Androgens are medium of terminus growth of hair although the body. Local and system androgens convert the extensive terminal follicles into lesser vellus like structure. The out start of this type of alopecia is intensely irregular and the reason behind this existence of enough circulating steroidal hormones androgens and due to genetic predisposition. Effective treatments are available in the market as well as under clinical and preclinical testing. Many herbal formulations are also available but not FDA approved. Different conventional and NDDS formulations are already available in the market. To avoid various systemic side effects of both Finasteride and Minoxidil, topical formulations and natural products (nutrients, minerals, vitamins) now a days are being widely used to treat Androgenic alopecia. CAM (complementary and alternative medicine) provides the option to elect favorable, low-risk, adjuvant and alternative therapies. Herein, we offer a widespread review of topical marketed formulations, natural products, and CAM treatment options for AGA.

Transcriptomic regulation of seasonal coat color change in hares

Color molts from summer brown to winter white coats have evolved in several species to maintain camouflage year-round in environments with seasonal snow. Despite the eco-evolutionary relevance of this key phenological adaptation, its molecular regulation has only recently begun to be addressed. Here, we analyze skin transcription changes during the autumn molt of the mountain hare (Lepus timidus) and integrate the results with an established model of gene regulation across the spring molt of the closely related snowshoe hare (L. americanus). We quantified differences in gene expression among three stages of molt progression-"brown" (early molt), "intermediate," and "white" (late molt). We found 632 differentially expressed genes, with a major pulse of expression early in the molt, followed by a milder one in late molt. The functional makeup of differentially expressed genes anchored the sampled molt stages to the developmental timeline of the hair growth cycle, associating anagen to early molt and the transition to catagen to late molt. The progression of color change was characterized by differential expression of genes involved in pigmentation, circadian, and behavioral regulation. We found significant overlap between differentially expressed genes across the seasonal molts of mountain and snowshoe hares, particularly at molt onset, suggesting conservatism of gene regulation across species and seasons. However, some discrepancies suggest seasonal differences in melanocyte differentiation and the integration of nutritional cues. Our established regulatory model of seasonal coat color molt provides an important mechanistic context to study the functional architecture and evolution of this crucial seasonal adaptation.

Mice lacking the epidermal retinol dehydrogenases SDR16C5 and SDR16C6 display accelerated hair growth and enlarged meibomian glands

Retinol dehydrogenases catalyze the rate-limiting step in the biosynthesis of retinoic acid, a bioactive lipid molecule that regulates the expression of hundreds of genes by binding to nuclear transcription factors, the retinoic acid receptors. Several enzymes exhibit retinol dehydrogenase activities in vitro; however, their physiological relevance for retinoic acid biosynthesis in vivo remains unclear. Here, we present evidence that two murine epidermal retinol dehydrogenases, short-chain dehydrogenase/reductase family 16C member 5 (SDR16C5) and SDR16C6, contribute to retinoic acid biosynthesis in living cells and are also essential for the oxidation of retinol to retinaldehyde in vivo Mice with targeted knockout of the more catalytically active SDR16C6 enzyme have no obvious phenotype, possibly due to functional redundancy, because Sdr16c5 and Sdr16c6 exhibit an overlapping expression pattern during later developmental stages and in adulthood. Mice that lack both enzymes are viable and fertile but display accelerated hair growth after shaving and also enlarged meibomian glands, consistent with a nearly 80% reduction in the retinol dehydrogenase activities of skin membrane fractions from the Sdr16c5/Sdr16c6 double-knockout mice. The up-regulation of hair-follicle stem cell genes is consistent with reduced retinoic acid signaling in the skin of the double-knockout mice. These results indicate that the retinol dehydrogenase activities of murine SDR16C5 and SDR16C6 enzymes are not critical for survival but are responsible for most of the retinol dehydrogenase activity in skin, essential for the regulation of the hair-follicle cycle, and required for the maintenance of both sebaceous and meibomian glands.

Resistin-like Molecule α Provides Vitamin-A-Dependent Antimicrobial Protection in the Skin

Vitamin A deficiency increases susceptibility to skin infection. However, the mechanisms by which vitamin A regulates skin immunity remain unclear. Here, we show that resistin-like molecule α (RELMα), a small secreted cysteine-rich protein, is expressed by epidermal keratinocytes and sebocytes and serves as an antimicrobial protein that is required for vitamin-A-dependent resistance to skin infection. RELMα was induced by microbiota colonization of the murine skin, was bactericidal in vitro, and was protected against bacterial infection of the skin in vivo. RELMα expression required dietary vitamin A and was induced by the therapeutic vitamin A analog isotretinoin, which protected against skin infection in a RELMα-dependent manner. The RELM family member Resistin was expressed in human skin, was induced by vitamin A analogs, and killed skin bacteria, indicating a conserved function for RELM proteins in skin innate immunity. Our findings provide insight into how vitamin A promotes resistance to skin infection.

Examination of Fluconazole-Induced Alopecia in an Animal Model and Human Cohort

Fluconazole-induced alopecia is a significant problem for patients receiving long-term therapy. We evaluated the hair cycle changes of fluconazole in a rat model and investigated potential molecular mechanisms. Plasma and tissue levels of retinoic acid were not found to be causal. Human patients with alopecia attributed to fluconazole also underwent detailed assessment and in both our murine model and human cohort fluconazole induced telogen effluvium. Future work further examining the mechanism of fluconazole-induced alopecia should be undertaken.

Cellular retinol-binding protein-1 expression increases with increasing clinical severity of alopecia areata

BACKGROUND

Alopecia areata (AA) is multifactorial disease mostly autoimmune affecting anagen hair follicles. Many researchers hypothesize that adequate retinoic acid (RA) levels are important for proper hair follicle behavior. Previous animal studies revealed increase in RA synthesis proteins and decrease in RA degradation proteins in AA patients when compared with controls.

OBJECTIVE

To evaluate cellular retinol-binding protein-1 expression in lesional skin of alopecia areata in comparison with controls, in an attempt to know its role in the pathogenesis of alopecia areata .

METHODS

Immunohistochemical expression of cellular retinol-binding protein-1 CRBP1 was evaluated in skin biopsies taken from lesions of alopecia areata in 30 patients and 10 normal biopsy specimens taken from skin of healthy controls (HC) who were within the same age and sex.

RESULTS

CRBP1 expression was significantly increased in lesional alopecia areata skin in comparison with normal skin of controls (P < 0.001*). Significant positive correlation was found between expression of CRBP-1 and percentage of hair loss in the scalp (SALT score; r = 0.840, P = <0.001).

CONCLUSION

These results may enhance the idea of the possible role of CRBP1 in the pathogenesis of AA, and ensuring the importance of its level in AA treatment.

The Role of Vitamins and Minerals in Hair Loss: A Review

People commonly inquire about vitamin and mineral supplementation and diet as a means to prevent or manage dermatological diseases and, in particular, hair loss. Answering these queries is frequently challenging, given the enormous and conflicting evidence that exists on this subject. There are several reasons to suspect a role for micronutrients in non-scarring alopecia. Micronutrients are major elements in the normal hair follicle cycle, playing a role in cellular turnover, a frequent occurrence in the matrix cells in the follicle bulb that are rapidly dividing. Management of alopecia is an essential aspect of clinical dermatology given the prevalence of hair loss and its significant impact on patients’ quality of life. The role of nutrition and diet in treating hair loss represents a dynamic and growing area of inquiry. In this review we summarize the role of vitamins and minerals, such as vitamin A, vitamin B, vitamin C, vitamin D, vitamin E, iron, selenium, and zinc, in non-scarring alopecia. A broad literature search of PubMed and Google Scholar was performed in July 2018 to compile published articles that study the relationship between vitamins and minerals, and hair loss. Micronutrients such as vitamins and minerals play an important, but not entirely clear role in normal hair follicle development and immune cell function. Deficiency of such micronutrients may represent a modifiable risk factor associated with the development, prevention, and treatment of alopecia. Given the role of vitamins and minerals in the hair cycle and immune defense mechanism, large double-blind placebo-controlled trials are required to determine the effect of specific micronutrient supplementation on hair growth in those with both micronutrient deficiency and non-scarring alopecia to establish any association between hair loss and such micronutrient deficiency.

Plain Language Summary: Plain language summary available for this article.

Use of adapalene in alopecia areata: Efficacy and safety of mometasone furoate 0.1% cream versus combination of mometasone furoate 0.1% cream and adapalene 0.1% gel in alopecia areata

Alopecia areata (AA) is an autoimmune disease characterized by non-cicatricial hair loss. No definitive therapy currently exists for AA. To compared the efficacy and safety of the mometasone furoate 0.1% cream alone with the mometasone furoate 0.1% cream plus adapalene 0.1% gel in treatment of AA. Twenty patients with AA and with mean age of 27.4 ± 9.2 years were enrolled. Patches with a diameter of < 5 cm were treated with mometasone furate 0.1% cream (M), and patches with a diameter of ≥5 cm were treated with mometasone furate 0.1% cream plus adapalene 0.1% gel (M + D) for a period of 12 weeks. Hair regrowth was evaluated using a Re-growth score (RGS). Mean RGSs of M + D group were higher than M group for 4th week (2.60 vs. 1.45); 8th week (3.85 vs. 2.40) and 12th week (4.40 vs. 3.30). Mean percentages of hair re-growth in M + D group were statistically higher than M group for 4th (50.2% vs. 23.5%), 8th (78.5% vs. 50.7%), and 12th week (90.5% vs. 71%). Study revealed the efficacy and safety of adapalene and mometasone furoate combination in AA. Adapalene can be used as a new therapeutic modality in AA.

Diet and hair loss: effects of nutrient deficiency and supplement use

Patients presenting with hair loss should be screened by medical history, dietary history and physical exam for risk factors for nutrient deficiency. If warranted, laboratory studies may be performed. In patients with no risk factors, further laboratory evaluation searching for nutritional deficiencies is not warranted. For patients with nutritional deficiencies, it is clear that those deficiencies should be corrected. Further research is required to determine whether any benefit exists for nutrient supplementation in the absence of documented deficiency. At this time, patients must be informed that such research is lacking and that in fact some supplements carry the risk of worsening hair loss or the risk of toxicity.

Characterization of human short chain dehydrogenase/reductase SDR16C family members related to retinol dehydrogenase 10

All-trans-retinoic acid (RA) is a bioactive derivative of vitamin A that serves as an activating ligand for nuclear transcription factors, retinoic acid receptors. RA biosynthesis is initiated by the enzymes that oxidize retinol to retinaldehyde. It is well established that retinol dehydrogenase 10 (RDH10, SDR16C4), which belongs to the 16C family of the short chain dehydrogenase/reductase (SDR) superfamily of proteins, is the major enzyme responsible for the oxidation of retinol to retinaldehyde for RA biosynthesis during embryogenesis. However, several lines of evidence point towards the existence of additional retinol dehydrogenases that contribute to RA biosynthesis in vivo. In close proximity to RDH10 gene on human chromosome 8 are located two genes that are phylogenetically related to RDH10. The predicted protein products of these genes, retinol dehydrogenase epidermal 2 (RDHE2, SDR16C5) and retinol dehydrogenase epidermal 2-similar (RDHE2S, SDR16C6), share 59% and 56% sequence similarity with RDH10, respectively. Previously, we showed that the single ortholog of the human RDHE2 and RDHE2S in frogs, Xenopus laevis rdhe2, oxidizes retinol to retinaldehyde and is essential for frog embryonic development. In this study, we explored the potential of each of the two human proteins to contribute to RA biosynthesis. The results of this study demonstrate that human RDHE2 exhibits a relatively low but reproducible activity when expressed in either HepG2 or HEK293 cells. Expression of the native RDHE2 is downregulated in the presence of elevated levels of RA. On the other hand, the protein encoded by the human RDHE2S gene is unstable when expressed in HEK293 cells. RDHE2S protein produced in Sf9 cells is stable but has no detectable catalytic activity towards retinol. We conclude that the human RDHE2S does not contribute to RA biosynthesis, whereas the low-activity RA-sensitive human RDHE2 may have a role in adjusting the cellular levels of RA in accord with specific physiological conditions.

Differential expression and functionality of ATP-binding cassette transporters in the human hair follicle

BACKGROUND

ATP-binding cassette (ABC) transporters are involved in the active transport of an extremely diverse range of substrates across biological membranes. These transporters are commonly implicated in the development of multidrug resistance and are also involved in numerous physiological and homeostatic processes, including lipid transport, cell migration and differentiation.

OBJECTIVES

To close the knowledge gap in the expression of ABC transporters in the human hair follicle (HF).

METHODS

Quantitative polymerase chain reaction (qPCR) of ABC genes and immunofluorescence microscopy analysis of cryosections of human HFs.

RESULTS

By qPCR analysis, numerous members of the ABC transporter superfamily, such as ABCB1, ABCG2 and ABCA12, were found to be transcribed in full-length human scalp HFs. Immunofluorescence microscopy demonstrated that the intrafollicular protein expression of different xenobiotic ABC transporters (ABCB1, ABCC1, ABCC4, ABCG2) varies greatly, with ABCG2 expression restricted primarily to the epithelial stem cell region of the outer root sheath (bulge), whereas expression of ABCB1, ABCC1 and ABCC4 was more widespread. Lipid transporters ABCA1, ABCA12 and ABCA4 were almost uniformly expressed throughout the HF epithelium. Functional ABCB1/G2 activity was demonstrated by exclusion of the substrate dye, Hoechst 33342. In the bulge, this was reversed by ABCB1 and ABCG2 inhibition.

CONCLUSIONS

These data encourage further investigation of ABC transporters as potentially important regulators of HF epithelial biology. Clinically, pharmacological modulation of the activity of selected intrafollicular ABC transporters may permit novel therapeutic interventions, such as protecting HF stem cells from chemotherapy-induced damage, counteracting cholesterol-associated hypertrichosis, and manipulating the intrafollicular prostaglandin balance in androgenetic alopecia.

Systemic treatment of seborrheic dermatitis with retinol palmitate

The goal of the study. Evaluating of the effectiveness of treatment of men with a diagnosis «Seborrheic dermatitis of the scalp» by the system using of retinol palmitate. Material and methods. 36 patients every day for 2 months received overnight per os 200000 ME of retinol palmitate, and in the comparison group (39 people) antiseborrheic shampoos have been used. The dynamics of severity of skin oiliness, pruritis, erythema, peeling, infiltration, excoriations has been evaluated in points. Before and after the treatment a histological and morphometric study of biopsy material from the affected areas has been carried.The terms of relapses have been set. Results. Retinol palmitate treatment efficiency - 91.7%, antiseborrheic shampoos - 84.6%. Along with the regression of symptoms of the disease in both groups after retinol palmitate treatment significantly declined oiliness of skin; the sizes of sebaceous glands acini and the presence of differentiated sebocytes, the squares of lymphocytic-macrophage clusters in the dermis, the number of keratinocytes with vacuolated cytoplasm have been reduced. Relapses of the disease during a year occured more rare - in 21 patients out of 32 (in the comparison group- in 25 out of 31) and at a later date (in the first 3 months in 2 patients out of 32, in comparison group in 10 out of 31). Identified effects were due to the action of retinol palmitate on the morphogenesis of the sebaceous glands.

Dietary vitamin A regulates wingless-related MMTV integration site signaling to alter the hair cycle

Alopecia areata (AA) is an autoimmune hair loss disease caused by a cell-mediated immune attack of the lower portion of the cycling hair follicle. Feeding mice 3-7 times the recommended level of dietary vitamin A accelerated the progression of AA in the graft-induced C3H/HeJ mouse model of AA. In this study, we also found that dietary vitamin A, in a dose dependent manner, activated the hair follicle stem cells (SCs) to induce the development and growth phase of the hair cycle (anagen), which may have made the hair follicle more susceptible to autoimmune attack. Our purpose here is to determine the mechanism by which dietary vitamin A regulates the hair cycle. We found that vitamin A in a dose-dependent manner increased nuclear localized beta-catenin (CTNNB1; a marker of canonical wingless-type Mouse Mammary Tumor Virus integration site family (WNT) signaling) and levels of WNT7A within the hair follicle bulge in these C3H/HeJ mice. These findings suggest that feeding mice high levels of dietary vitamin A increases WNT signaling to activate hair follicle SCs.

Emerging treatments in alopecia

INTRODUCTION

Alopecia is a common concern encountered in the medical practice. Treatment approach varies according to the type and severity of alopecia. However, available treatment options have limited efficacy and several adverse effects. Presently, there are different treatment options being studied to overcome these limitations. Additionally, cellular pathways involved in the pathophysiology of alopecia are further being clarified to potentially target pathogenic molecules.

AREAS COVERED

We searched the literature for recently published articles discussing new treatment options as well as mechanisms involved in alopecia. We discuss the use of stem cells, growth factors, cellular pathways and robotic hair transplant, among other emerging therapies used for alopecia.

EXPERT OPINION

Future looks very promising and new effective treatments such as janus kinase inhibitors could possibly be available for alopecia areata. The stem-cell technology is advancing and companies involved in hair follicle neogenesis are starting clinical trials on patients with androgenetic alopecia.

Pharmacological inhibition of DGAT1 induces sebaceous gland atrophy in mouse and dog skin while overt alopecia is restricted to the mouse

Diacylglycerol O-acyltransferase 1 (DGAT1) plays an important role in synthesizing lipids, and inhibitors of DGAT1 have been investigated as potential treatments for diabetes and metabolic diseases. DGAT1 knockout (-/-) mice are resistant to obesity, have increased sensitivity to insulin, and exhibit sebaceous gland atrophy and alopecia. Prolonged pharmacological inhibition of DGAT1 with AZD7687 in mice results in the same skin phenotype, including sebaceous gland atrophy and alopecia, as seen in the skin of DGAT1 (-/-) mice. AZD7687-mediated effects on the skin were dose- and time-dependent and reversible. They occurred only at substantial levels of continuous DGAT1 inhibition. Prolonged treatment of dogs with AZD7687 also resulted in sebaceous gland atrophy but did not result in the more adverse skin changes of hair loss and skin lesions. Our findings highlight a significant risk of generating the same lesions that were seen in mouse skin during clinical development of DGAT1 inhibitors in humans and also reveal a species difference in the effects on the skin, indicating that the mouse may be an especially sensitive species. Therefore, although human therapeutic doses may not have the same influence on skin morphology as seen in mice, monitoring of skin changes will be essential in clinical trials with DGAT1 inhibitors.

Exploring differentially expressed genes by RNA-Seq in cashmere goat (Capra hircus) skin during hair follicle development and cycling

Cashmere goat (Capra hircus) hair follicle development and cycling can be divided into three stages: anagen, catagen and telogen. To elucidate the genes involved in hair follicle development and cycling in cashmere goats, transcriptome profiling of skin was carried out by analysing samples from three hair follicle developmental stages using RNA-Seq. The RNA-Seq analysis generated 8487344, 8142514 and 7345335 clean reads in anagen, catagen and telogen stages, respectively, which provided abundant data for further analysis. A total of 1332 differentially expressed genes (DEGs) were identified, providing evidence that the development of hair follicles among the three distinct stages changed considerably. A total of 683 genes with significant differential expression were detected between anagen and catagen, 530 DEGs were identified between anagen and telogen, and 119 DEGs were identified between catagen and telogen. A large number of DEGs were predominantly related to cellular process, cell & cell part, binding, biological regulation and metabolic process among the different stages of hair follicle development. In addition, the Wnt, Shh, TGF-β and Notch signaling pathways may be involved in hair follicle development and the identified DEGs may play important roles in these signaling pathways. These results will expand our understanding of the complex molecular mechanisms of hair follicle development and cycling in cashmere goats and provide a foundation for future studies.

Endogenous retinoids in the pathogenesis of alopecia areata

Alopecia areata (AA) is an autoimmune disease that attacks anagen hair follicles. Gene array in graft-induced C3H/HeJ mice revealed that genes involved in retinoic acid (RA) synthesis were increased, whereas RA degradation genes were decreased in AA compared with sham controls. This was confirmed by immunohistochemistry in biopsies from patients with AA and both mouse and rat AA models. RA levels were also increased in C3H/HeJ mice with AA. C3H/HeJ mice were fed a purified diet containing one of the four levels of dietary vitamin A or an unpurified diet 2 weeks before grafting and disease progression followed. High vitamin A accelerated AA, whereas mice that were not fed vitamin A had more severe disease by the end of the study. More hair follicles were in anagen in mice fed high vitamin A. Both the number and localization of granzyme B-positive cells were altered by vitamin A. IFNγ was also the lowest and IL13 highest in mice fed high vitamin A. Other cytokines were reduced and chemokines increased as the disease progressed, but no additional effects of vitamin A were seen. Combined, these results suggest that vitamin A regulates both the hair cycle and immune response to alter the progression of AA.

Retinoid metabolism is altered in human and mouse cicatricial alopecia

C57BL/6 mice develop dermatitis and scarring alopecia resembling human cicatricial alopecias (CA), particularly the central centrifugal cicatricial alopecia (CCCA) type. To evaluate the role of retinoids in CA, expression of retinoid metabolism components were examined in these mice with mild, moderate, or severe CA compared to hair cycle matched mice with no disease. Two feeding studies were performed with dams fed either NIH 31 diet (study 1) or AIN93G diet (study 2). Adult mice were fed AIN93M diet with 4 (recommended), 28, or 56 IU vitamin A/g diet. Feeding the AIN93M diet to adults increased CA frequency over NIH 31 fed mice. Increased follicular dystrophy was seen in study 1 and increased dermal scars in study 2 in mice fed the 28 IU diet. These results indicate that retinoid metabolism is altered in CA in C57BL/6J mice that require precise levels of dietary vitamin A. Human patients with CCCA, pseudopelade (end stage scarring), and controls with no alopecia were also studied. Many retinoid metabolism proteins were increased in mild CCCA, but were undetectable in pseudopelade. Studies to determine if these dietary alterations in retinoid metabolism seen in C57BL/6J mice are also involved in different types of human CA are needed.

Cutaneous retinoic acid levels determine hair follicle development and downgrowth

Retinoic acid (RA) is essential during embryogenesis and for tissue homeostasis, whereas excess RA is well known as a teratogen. In humans, excess RA is associated with hair loss. In the present study, we demonstrate that specific levels of RA, regulated by Cyp26b1, one of the RA-degrading enzymes, are required for hair follicle (hf) morphogenesis. Mice with embryonic ablation of Cyp26b1 (Cyp26b1(-/-)) have excessive endogenous RA, resulting in arrest of hf growth at the hair germ stage. The altered hf development is rescued by grafting the mutant skin on immunodeficient mice. Our results show that normalization of RA levels is associated with reinitiation of hf development. Conditional deficiency of Cyp26b1 in the dermis (En1Cre;Cyp26b1f/-) results in decreased hair follicle density and specific effect on hair type, indicating that RA levels also influence regulators of hair bending. Our results support the model of RA-dependent dermal signals regulating hf downgrowth and bending. To elucidate target gene pathways of RA, we performed microarray and RNA-Seq profiling of genes differentially expressed in Cyp26b1(-/-) skin and En1Cre;Cyp26b1f/- tissues. We show specific effects on the Wnt-catenin pathway and on members of the Runx, Fox, and Sox transcription factor families, indicating that RA modulates pathways and factors implicated in hf downgrowth and bending. Our results establish that proper RA distribution is essential for morphogenesis, development, and differentiation of hfs.