Hair Bulb Research Articles

The role of salivary vitamin D and interleukin-6 on non-scarring Alopecia.

Alopecia, or hair loss, is an emerging global disease. Its etiopathogenesis includes nutritional deficiencies, oxidative stress, and deficiency of physiological factors. Around 2% of the general population has the probability of developing alopecia at any one period. Vitamin D and interleukin-6 (IL-6) have a major role in alopecia. The present goal of research is to investigate the role of vitamin D and IL-6 in the saliva of patients with non-scarring alopecia. The study involved 51 cases of non-scarring alopecia and 50 healthy controls with an age range between 18 and 40 years. A detailed history and clinical examination were done. Salivary vitamin D and IL-6 were determined to compare within the groups. The average vitamin D level in cases (104.64 ± 46.95 pmol/L) was significantly lower as compared to controls (223 ± 12.03 pmol/L) (p < 0.001). Whereas the average amount of IL-6 was significantly higher (170.54 ± 63.68 ng/L) than the control group (56.38 ± 46.52 ng/L) (p < 0.001). No correlation of vitamin D level with IL-6 was detected in study subjects. Vitamin D significantly influences the development of non-scarring alopecia. Patients with non-scarring alopecia had low amount of vitamin D indicate its role in etiology of hair loss. IL-6 may cause a collapse of the hair bulb, having a significant part in the pathogenesis of alopecia indicating chronic inflammatory or autoimmune condition. This research will aid in diagnosing scalp disease using salivary biomarkers and improve the treatment of alopecia.

Elevated anti‐Müllerian hormone in a stallion (Equus f. caballus) with terratoma and high inguinal testicle

AbstractThis report describes a stallion presenting a unilateral high inguinal undescended testicle and a unilateral scrotal testicle teratoma. Blood tests showed increased levels of anti‐Müllerian hormone. Following castration, histological examination revealed that the teratoma contained testicular tissue, hair, hair bulbs, sebaceous glands, cartilage and endochondral bone. To our knowledge, this is the first study to report elevated anti‐Müllerian hormone levels in a stallion with both a teratoma and a high‐inguinal testicle.

Deconvolving organogenesis in space and time via spatial transcriptomics in thick tissues.

Organ development is guided by a space-time landscape that constraints cell behavior. This landscape is challenging to characterize for the hair follicle - the most abundant mini organ - due to its complex microscopic structure and asynchronous development. We developed 3DEEP, a tissue clearing and spatial transcriptomic strategy for characterizing tissue blocks up to 400 µm in thickness. We captured 371 hair follicles at different stages of organogenesis in 1 mm 3 of skin of a 12-hour-old mouse with 6 million transcripts from 81 genes. From this single time point, we deconvoluted follicles by age based on whole-organ molecular pseudotimes to animate a stop-motion 3D atlas of follicle development along its trajectory. We defined molecular stages for hair follicle organogenesis and characterized the order of emergence for its structures, differential signaling dynamics at its top and bottom, morphogen shifts preceding and accompanying structural changes, and series of structural changes leading to the formation of its canal and opening. We further found that hair follicle stem cells and their niche are established and stratified early in organogenesis, before the formation of the hair bulb. Overall, this work demonstrates the power of increased depth of spatial transcriptomics to provide a four-dimensional analysis of organogenesis.

Age-related changes in the hair follicle and hair shaft in women in the parietal region

Introduction. Medical trichology is a promising and modern direction of cosmetology, engaged in the study of the scalp and hair, both in the state of health and various diseases. However, with all the variety of various scientific publications, there are very few works devoted to the study of morphological changes in normal physiological aging of a person.Aim. To reveal the dynamics of morphological changes in the hair bulb and hair shaft in women in the parietal region to elderly age.Materials and methods. The work is based on the results of microscopic examination of 80 women, the study sample consisted of conditionally healthy individuals. The examined women were divided into three groups depending on their age. The first group included 27 women of the first period of mature age (26.9 ± 0.70 years). The second group consisted of 30 women of the second period of mature age (47.1 ± 1.20 years). The third group was formed by 23 women of old age (62.1 ± 1.09 years). Hair sampling was performed in the parietal region of the head by combing out the hair that had already fallen out (without pulling it out of the skin!). The width of the hair bulb and hair shaft were measured. The percentage of bulbs containing an internal root sheath to the total number of bulbs was calculated.Results and discussion. With age, a decrease in the number of hair follicles with internal root sheath (p &lt; 0.01) along with a tendency to decrease the width of the hair follicle and hair shaft (p &gt; 0.05) was noted in women in the parietal region.Conclusions. The results of this study add to the information available in the scientific literature about age-related changes occurring in the hair bulb and hair shaft in women by old age. The data obtained will be useful for trichologists in medical practice to create clinical recommendations for the early prevention of age-related alopecia areata.

Incorporation of suvorexant and lemborexant into hair and their distributions after a single intake.

This study examined the applicability of hair analysis as an approach to identify suvorexant (SUV) and lemborexant (LEM) intake by analyzing black hair specimens collected from study participants after a single oral administration. Hair specimens were collected form participants who took a single dose of 10 mg SUV or 5 mg LEM. Identification of the dual orexin receptor antagonists (DORAs) and their metabolites was performed by liquid chromatography-tandem mass spectrometry. Reference standards of S-M9 and L-M4, the metabolites of SUV and LEM, respectively, were synthesized in our laboratory. Sectional analysis of 1-mm segments of the single-hair strands was also performed to investigate the incorporation behavior of the drugs into hair. Unchanged SUV and LEM, and their metabolites S-M9 and L-M4 were detected even in the single-hair specimens. Results of the segmental hair analysis showed predominant incorporation of the drugs into hair through the hair bulb region rather than through the upper dermis zone of the hair root. The drug concentrations in the hair specimens, collected about 1month after intake, were 0.033-0.037pg/hair strand (0.17-0.19pg/mg) for SUV and 0.054-0.28pg/hair strand (0.28-1.5pg/mg) for LEM. The calculated distribution ratios of the DORAs into hair to the oral doses were much lower than those of benzodiazepines and zolpidem reported in a previous study. This is the first report of the detection of the DORAs in hair. The incorporation behavior of the DORAs into hair revealed herein are crucial for proper interpretation of hair test results.

Laser-Induced Koebner-Related Skin Reactions: A Clinical Overview.

The Koebner phenomenon (KP), also known as the isomorphic response, describes the process by which new lesions that are clinically and histologically identical to a patient's existing skin disease develop following trauma. Many skin diseases exhibit this characteristic, with variations that include possible, questionable, and pseudo-Koebner reactions, with the latter category occurring due to infectious agents seeding at a trauma site. Laser application, a type of controlled skin injury used for improving cutaneous lesions and skin rejuvenation, is also considered a form of trauma. This raises the question of whether controlled thermal injury can be regarded as a type of mechanical trauma capable of producing Koebner-related reactions. We conducted a literature review of cases or studies to identify laser-induced dermatoses that correspond to Koebner-related or pathergy reaction categories. As a whole, we identified nine case reports on true KPs, two cases on possible KPs, seventeen cases on laser-induced questionable KPs comprising cases of vasculitis, eczema or Meyerson reactions, and eruptive squamous atypia cases (ESA) as well as two pseudo-Koebner cases involving wart occurrences at laser application sites. Laser-induced Koebner reactions highlight several aspects of the KP. Firstly, the type of mechanical damage influences disease promotion, as different lasers are associated with different KPs. For example, hair removal lasers are linked with true and questionable KPs such as vasculitis while resurfacing lasers were found to be more connected with ESA occurrence. Secondly, the laser target is significant, with vascular laser application for port-wine stains tending to result in eczematous reactions, while hair follicle destruction can frequently lead to true KPs. Thirdly, the number of sessions matters; true KPs and eruptive squamous atypia questionable KPs typically appear after one to two sessions, whereas eczematous reactions require more sessions (at least four). Additionally, skin phototype is crucial, with darker phototypes showing a higher KP frequency as laser treatment for hypertrichosis relies on melanin absorption in the hair bulge or bulb for follicle destruction, as chromophore competes with the abundant melanin in the epidermis. Further research with larger-scale studies into trauma-specific Koebner reactions is vital for refining treatment protocols, minimizing post-laser adverse effects, and improving dermatological care outcomes.

Pilose antler extracts promotes hair growth in androgenetic alopecia mice by activating hair follicle stem cells via the AKT and Wnt pathways.

Background: Angrogenetic alopecia (AGA) is one of the most prevalent hair loss disorders worldwide. The hair follicle stem cell (HFSC) is closely related to the formation of hair follicle (HF) structure and HF self-renewal. The activation of HFSC in AGA is critical for hair growth. Pilose antler has been reported to have hair growth-promoting activity, but the mechanism of action on AGA and HFSC has not been reported. Methods: We previously extracted an active component from the pilose antler known as PAEs. In this study, we conducted experiments using AGA mice and HFSC. The effects of PAEs on hair growth in AGA mice were firstly detected, and then the mechanisms of PAEs for AGA were predicted by integrating network pharmacology and de novo transcriptomics data of pilose antler. Finally, biological experiments were used to validate the molecular mechanism of PAEs in treating AGA both in vivo and in vitro. Results: It was found that PAEs promoted hair regrowth by accelerating the activation of anagen, delaying the anagen-catagen transition. It also alleviated the morphological changes, such as hair shortening, thinning, miniaturization, and HF number reduction, and regulated the hair regeneration process of four subtypes of hair. We further found that PAEs could promote the proliferation of HFSC, outer root sheath (ORS) cells, and hair bulb cells in AGA mice. We then integrated network pharmacology and pilose antler transcriptomics data to predict that the mechanism of PAEs treatment in AGA mice is closely related to the PI3K-AKT/Wnt-β-Catenin pathways. Subsequently, it was also verified that PAEs could activate both pathways in the skin of AGA mice. In addition, we found that PAEs perhaps increased the number of blood vessels around dermal papilla (DP) in experiments in vivo. Meanwhile, the PAEs stimulated the HFSC proliferation in vitro and activated the AKT and Wnt pathways. However, the proliferative activity of HFSC was inhibited after blocking the Wnt pathway and AKT activity. Conclusion: This study suggests that the hair growth-promoting effect of PAEs in AGA mice may be closely related to the stimulation of the AKT and Wnt pathways, which in turn activates the proliferation of HFSC.

Unusual sex chromosomal DSD in a domestic Shorthair cat with a 37,X/38,XY mosaic karyotype

BackgroundSex chromosome abnormalities associated with disorders of sexual development (DSD) are rarely described in cats, mainly due to the lack of chromossome studies that precisely reveal the condition. Genetic approaches are therefore required in order to detect sex chromossomes abnormalities as variations in the number and structure of chromosomes, or the presence of a second cell line as mosaicim or chimerism.Case presentationA male Shorthair cryptorchid cat was presented with clinical signs of anorexia, tenesmus and hyperthermia. Ultrasonography revealed a fluid-filled structure, with approximately 1 cm in diameter, adjacent to the descending colon. Computed tomography evidenced a tubular structure, ventral to the descending colon and caudal to the bladder, which extended cranially, through two branches. Histopathological evaluation confirmed the presence of two atrophic uterine horns and one hypoplastic testicle with epididymis at the end of one of the uterine horns. The end of the other uterine horn was attached to a structure composed by a mass of adipocytes. Cytogenetic analysis revealed a mosaic 37,X/38,XY karyotype. The two cell lines were found in 15% and 85% of the lymphocytes, respectively. Genetic analysis confirmed the presence of SRY and ZFY genes in blood and hair bulbs, and revealed a marked reduction in SRY expression in the testicle. Additionally, this case presented exceptionally rare features, such as a Leydig’ cell tumour and a chronic endometritis in both uterine horns.ConclusionsComplete imaging workup, cytogenetic analysis and SRY gene expression should be systematically realized, in order to properly classify disorders of sexual development (DSD) in cats.

Assessing the efficacy of mesotherapy products: Ultra Exo Booster, and Ultra S Line Plus in hair growth: An ex vivo study.

In this study, scalp tissues from Korean adults between 20 and 80 without skin disease were used. Scalp tissues were processed, and hair follicles were isolated and cultured with different treatments (including Bioscalp, Ultra Exo Booster, and Ultra S Line Plus) from Ultra V company. Over 12 days, observations and measurements of hair follicle characteristics were recorded at intervals (Days 0, 3, 6, 9, and 12). The study assessed the impact of these substances on hair follicle growth and morphology. Bioscalp, combined with Ultra Exo Booster and Ultra S Line Plus, showed significant hair elongation in ex vivo. Preservation of hair bulb diameter was observed, indicating potential for sustained hair growth by exosome-based products. The hair growth cycle analysis suggested a lower transition to the catagen stage in test products from Ultra V compared to non-treated groups. The research findings indicated that the tested formulations, especially the combination of Bioscalp, Ultra Exo Booster, and Ultra S Line Plus, demonstrated significant effectiveness in promoting hair growth, maintaining the integrity of the hair bulb, and reducing the transition to the catagen stage. The study suggests promising alternative treatments for hair loss, illustrating results that were as good as those of the conventional testing product groups.

Stimulation of hair regrowth in an animal model of androgenic alopecia using 2-deoxy-D-ribose.

Androgenic alopecia (AGA) affects both men and women worldwide. New blood vessel formation can restore blood supply and stimulate the hair regrowth cycle. Recently, our group reported that 2-deoxy-D-ribose (2dDR) is 80%-90% as effective as VEGF in the stimulation of neovascularization in in vitro models and in a chick bioassay. In this study, we aimed to assess the effect of 2dDR on hair growth. We prepared an alginate gel containing 2dDR, polypropylene glycol, and phenoxyethanol. AGA was developed in C57BL6 mice by intraperitoneally injecting testosterone (TE). A dihydrotestosterone (DHT)-treated group was used as a negative control, a minoxidil group was used as a positive control, and we included groups treated with 2dDR gel and a combination of 2dDR and minoxidil. Each treatment was applied for 20 days. Both groups treated with 2dDR gel and minoxidil stimulated the morphogenesis of hair follicles. H&E-stained skin sections of C57BL/6 mice demonstrated an increase in length, diameter, hair follicle density, anagen/telogen ratio, diameter of hair follicles, area of the hair bulb covered in melanin, and an increase in the number of blood vessels. Masson's trichrome staining showed an increase in the area of the hair bulb covered in melanin. The effects of the FDA-approved drug (minoxidil) on hair growth were similar to those of 2dDR (80%-90%). No significant benefit were observed by applying a combination of minoxidil with 2dDR. We conclude that 2dDR gel has potential for the treatment of androgenic alopecia and possibly other alopecia conditions where stimulation of hair regrowth is desirable, such as after chemotherapy. The mechanism of activity of 2dDR remains to be established.

Germline Predisposition in Hematologic Malignancies: Testing, Management, and Implications.

Although numerous barriers for clinical germline cancer predisposition testing exist, the increasing recognition of deleterious germline DNA variants contributing to myeloid malignancy risk is yielding steady improvements in referrals for testing and testing availability. Many germline predisposition alleles are common in populations, and the increasing number of recognized disorders makes inherited myeloid malignancy risk an entity worthy of consideration for all patients regardless of age at diagnosis. Germline testing is facilitated by obtaining DNA from cultured skin fibroblasts or hair bulbs, and cascade testing is easily performed via buccal swab, saliva, or blood. Increasingly as diagnostic criteria and clinical management guidelines include germline myeloid malignancy predisposition, insurance companies recognize the value of testing and provide coverage. Once an individual is recognized to have a deleterious germline variant that confers risk for myeloid malignancies, a personalized cancer surveillance plan can be developed that incorporates screening for other cancer risk outside of the hematopoietic system and/or other organ pathology. The future may also include monitoring the development of clonal hematopoiesis, which is common for many of these cancer risk disorders and/or inclusion of strategies to delay or prevent progression to overt myeloid malignancy. As research continues to identify new myeloid predisposition disorders, we may soon recommend testing for these conditions for all patients diagnosed with a myeloid predisposition condition.

Trichology to predict efficacy of scalp cooling: New pathologic insights besides encouraging clinical results.

12093 Background: Chemotherapy continues to be an essential element of tumour-specific systemic therapy. The associated hair loss impacts patients ‘quality of life in addition. Sensor-controlled scalp cooling has proven itself as a method of preventing alopecia. This study evaluates the grade of hair preservation as well as predictive factors, including (ultra)structural changes of the hair follicle during treatment, offering potential for enhanced therapeutic strategies. Methods: Scalp cooling, was evaluated in 81 patients (79 women, 2 men, median age 56 years) undergoing breast carcinoma treatment (4x EC 90/600 mg/m² BSA followed by 12x PAC w). Key outcomes included hair preservation (Hair Mass Index = HMI), avoidance of visible hair loss (HMI ≥ 50), and prevention of severe hair loss (all measured by Cross Section Trichometer). Parameters such as hair density (HMI), trichologic parameters like hair shaft and bulb diameter, anagen rate, shaft surface damage and melanosomes changes were measured through (ultrastructural) microscopy. Results: Over the half (53%) of patients avoided successfully noticeable hair loss (HMI post ≥ 50). Most important predictors of successful hair preservation in different analyses included lower post-therapeutic shaft surface damage (via scanning electron microscopy) (β = -.30, p = .034), larger pre-treatment shaft diameter (via light microscopy) (OR = 1.11, p = .011), and stable melanosome density (via transmission electron microscopy) (β = .35, p = .013). Higher anagen ratio (β = .30, p = 0.009) and larger hair shaft diameter (β = .29, p=0,023) plays a crucial role in hair prevention, considering only light-microspcopic parameters. Comorbidity (OR = 0.12, p = .024) and alopecia causing medication (e.g. antihypertensiva) (β = -.31, p = .017) led to increased hair loss. Patients with fewer hair loss over the course reported higher quality of life (r = .25, p = .042) and lower psychological burden (r = -.42, p &lt; .001). Data indicate that optimal pre-therapeutic hair density (HMI =/&gt; 69), coupled with the absence of comorbidities and alopecia-inducing medications, substantially enhances the efficacy of scalp cooling, elevating the probability of preventing severe hair loss (HMI ≥ 50) by nearly sevenfold (OR = 6.98, CI95% [1.01;48.33]. Conclusions: Scalp cooling proves effective in preventing visible hair loss in 53% of patients, with mini-organ (hair follicle) characteristics influencing outcomes. It does not only prevent hair loss but also enhances quality of life, underscoring the need for personalized approaches in managing chemotherapy-induced alopecia. The study confirms the method's safety and effectiveness without increasing scalp metastasis risk.

A phase 1, first-in-human, open-label study evaluating the safety, tolerability, pharmacokinetics, and efficacy of TT125-802 in patients with advanced solid tumors.

TPS3171 Background: TT125-802 is a selective, potent, orally bioavailable small molecule inhibitor of the bromodomain of CBP and p300, two highly homologues lysine acetyltransferases. CBP/p300 act as transcriptional co-activators with multiple domains and functions, including well-documented roles in cell cycle regulation and several critical tumorigenic pathways (1-3). TT125-802 has shown mono-therapy efficacy in preclinical models of castration-resistant prostate cancer, KRAS-mutated colorectal and non-small cell lung cancer (4,5). Furthermore, TT125-802 is capable to interfere with transcriptional resistance mechanisms limiting targeted therapies (6) which will be explored clinically upon determination of a safe, well-tolerated, and biologically active single-agent dose. Methods: This study aims to establish the safety, tolerability, and pharmacokinetic profile of TT125-802. The maximum tolerated dose/recommended dose for expansion (MTD/RDE) of repeat daily dosing for TT125-802 monotherapy will be determined in subjects with advanced solid tumors in a sequential escalating cohorts design, (1 cycle = 21 days) using the Bayesian Logistics Regression Model (BLRM) with sentinel patients (2-day window for first patient enrolled in each cohort). Cohorts will consist of 3 to 6 subjects who will be followed over a dose-limiting toxicity (DLT) period of at least 21 days. TT125-802 will be administered orally once daily; additional schedules may be evaluated. Dose escalation is planned to follow two-fold increments. It may be adapted upon dose level revision and guided by pharmacokinetic analysis. Additional subjects (up to 6) may be enrolled in at least two monotherapy cohorts deemed safe and tolerable to optimize the recommended phase 2 dose (RP2D). Up to a total of 20 additional subjects may be enrolled. Translational/pharmacodynamic endpoints: Exploratory endpoints will provide proof-of-principle and early biomarker data for CBP/p300 inhibition. These analyses will include: 1. Single-cell gene expression evaluation of peripheral blood mononuclear cells (PBMCs) at multiple time points, 2. anagen hair bulb bulk RNAseq analysis, and 3. paired tumor biopsies will be analyzed with single-cell RNA sequencing. Together, these investigations are expected to support optimal dose determination. Additionally, circulating tumor DNA might be evaluated to define molecular responses. Outlook: The recommended phase 2 dose will be used further to explore the efficacy of TT125-802 as monotherapy. TT125-802 will be evaluated with targeted therapies (for example, KRASG12C/D, BRAF, EGFR, etc., inhibitors) to exploit the blocking of transcriptional escape mechanisms driven by CBP/p300. 1. Iyer, 2007. 2. Dutta, 2016. 3. Attar, 2017. 4. AACR2023 posters #6268. 5. AACR poster #3907. 6. AACR2023 poster #3907. Clinical trial information: 2022-500849-24-00 .

P24 Folliculin silencing in human hair follicles ex vivo upregulates intrafollicular mechanistic target of rapamycin complex 1 activity: a new model for studying Birt–Hogg–Dubé syndrome

Abstract Introduction and aims Birt–Hogg–Dubé (BHD) syndrome is a rare multisystem disorder caused by germline pathogenic variants in the FLCN gene. BHD skin tumours predominantly affect facial skin, confer a significant psychosocial burden, and there is a lack of nonsurgical therapies. Here we report a novel ex vivo human model to study the impact of FLCN loss in human hair follicles (HFs), the putative origin of BHD skin tumours. Methods Organ-cultured human anagen HFs and scalp skin were treated with small interfering RNA targeting FLCN (n = 2 donors) for 6 days ex vivo, followed by quantitative real-time polymerase chain reaction (qRT-PCR), and quantitative immunohistomorphometry (qIHM). Results Successful FLCN knockdown was confirmed at both the mRNA (34% reduction compared with nontargeting control levels measured by qRT-PCR) and protein level (12% reduction in FLCN expression measured by qIHM). In FLCN-silenced HFs (n = 14, two donors), our preliminary Results demonstrated an increase in p-S6 expression, a direct downstream kinase of mechanistic target of rapamycin complex (mTORC)1 signalling. This was spatially restricted to the hair bulb and proximal outer root sheath keratinocytes, and was significantly greater than quantified in nontargeting control HFs (P &amp;lt; 0.05). Conclusions FLCN silencing in ex vivo cultured, healthy human HFs and scalp skin provides a novel, instructive and accessible preclinical research model. We aim to delineate whether FLCN interacts with the key endogenous inhibitor of mTORC1 activity, TSC2, in future work, to gain insight into the role of FLCN in the pathobiology of BHD and the maintenance of healthy human HFs.

Exogenous IL-27 prevents the development of alopecia areata

Abstract Alopecia areata (AA) is an autoimmune disease with a 2% lifetime incidence. Commonly presenting as defined patches of hair loss on the scalp, AA is characterized by the presence of T cells surrounding the hair bulb and is thought to result as a consequence of the breakdown of immune privilege of the hair follicle. IL-27 is a cytokine with context-dependent pro- and anti-inflammatory properties that has been used as a potential therapy in models of autoimmune diseases and cancer. The objective of this study was to determine if IL-27 has therapeutic potential in AA. To address this, we used an adeno-associated virus that drives the overexpression of IL-27 (AAV-IL27) in our skin-graft induction model of AA. We found that mice that received AAV-IL27 were fully protected from disease development and had minimal CD8 T cell infiltration into the hair follicles. Further, we saw an increase in IL-10 producing CD4 T cells, supporting a potential mechanism by which IL-27 prevents disease development. Interestingly, we found that mice treated with AAV-IL27 generated a robust population of NKG2D expressing CD8 T cells, which has previously been associated with the presence of disease. These results suggest that IL-27 may act in an immunoregulatory manner in AA, by promoting immunosuppressive T cells in the SDLNs. Further studies are needed to further define the specific mechanisms by which IL-27 contributes to the prevention of AA and its utility as a treatment for AA.

Pathogenesis of Alopecia Areata and Vitiligo: Commonalities and Differences.

Both alopecia areata (AA) and vitiligo are distinct, heterogenous, and complex disease entities, characterized by nonscarring scalp terminal hair loss and skin pigment loss, respectively. In AA, inflammatory cell infiltrates are in the deep reticular dermis close to the hair bulb (swarm of bees), whereas in vitiligo the inflammatory infiltrates are in the epidermis and papillary dermis. Immune privilege collapse has been extensively investigated in AA pathogenesis, including the suppression of immunomodulatory factors (e.g., transforming growth factor-β (TGF-β), programmed death-ligand 1 (PDL1), interleukin-10 (IL-10), α-melanocyte-stimulating hormone (α-MSH), and macrophage migration inhibitory factor (MIF)) and enhanced expression of the major histocompatibility complex (MHC) throughout hair follicles. However, immune privilege collapse in vitiligo remains less explored. Both AA and vitiligo are autoimmune diseases that share commonalities in pathogenesis, including the involvement of plasmacytoid dendritic cells (and interferon-α (IFN- α) signaling pathways) and cytotoxic CD8+ T lymphocytes (and activated IFN-γ signaling pathways). Blood chemokine C-X-C motif ligand 9 (CXCL9) and CXCL10 are elevated in both diseases. Common factors that contribute to AA and vitiligo include oxidative stress, autophagy, type 2 cytokines, and the Wnt/β-catenin pathway (e.g., dickkopf 1 (DKK1)). Here, we summarize the commonalities and differences between AA and vitiligo, focusing on their pathogenesis.

SOX-10 and TRP-1 expression in feline ocular and nonocular melanomas.

In felines, ocular and nonocular melanomas are uncommon tumors that represent a diagnostic challenge for pathologists, especially when amelanotic. To date, the immunohistochemical diagnostic panel in cats is based on specific melanocytic markers (Melan-A and PNL2) and a nonspecific but sensitive marker (S100). In human medicine, SOX-10 is reported to be a sensitive antibody for the detection of melanoma micrometastasis in the lymph node. TRP-1, an enzyme involved in melanogenesis, has recently been used in humans and dogs as a specific melanocyte marker. The aim of this study was to evaluate the cross-reactivity and the expression of SOX-10 and TRP-1 antibodies in feline normal tissue and melanocytic tumors. Thirty-one cases of ocular, cutaneous, and oral melanomas were retrospectively evaluated and confirmed by histopathological examination and by immunolabeling with Melan-A and/or PNL2. SOX-10 nuclear expression in normal tissues was localized in epidermal, subepidermal, hair bulb, and iridal stromal melanocytes and dermal nerves. In melanomas, nuclear expression of SOX-10 was detected in ocular (11/12; 92%), oral (6/7; 86%), and cutaneous sites (12/12; 100%). TRP-1 cytoplasmic immunolabeling in normal tissue was observed in epidermal and bulbar melanocytes and in the lining pigmented epithelium of the iris and in its stroma. Its expression was positively correlated to the degree of pigmentation in the tumor and was observed in 75% of ocular (9/12), 43% of oral (3/7), and 33% of cutaneous melanomas (4/12). This study demonstrated the cross-reactivity of SOX-10 and TRP-1 antibodies in feline non-neoplastic melanocytes and their expression in ocular and nonocular melanomas.

Interleukin-15 is a hair follicle immune privilege guardian

The autoimmunity-promoting cytokine, Interleukin-15 (IL-15), is often claimed to be a key pathogenic cytokine in alopecia areata (AA). Yet, rhIL-15 promotes human hair follicle (HF) growth ex vivo. We have asked whether the expression of IL-15 and its receptor (IL-15R) isoforms is altered in human AA and how IL-15 impacts on human HF immune privilege (HF-IP) in the presence/absence of interferon-γ (IFNγ), the well-documented key AA-pathogenic cytokine, as well as on hair regrowth after experimental AA induction in vivo. Quantitative immunohistomorphometry showed the number of perifollicular IL-15+ T cells in AA skin biopsies to be significantly increased compared to healthy control skin, while IL-15, IL-15Rα, and IL-15Rγ protein expression within the hair bulb were significantly down-regulated in AA HFs. In organ-cultured human scalp HFs, rhIL-15 significantly reduced hair bulb expression of MICA, the key “danger” signal in AA pathogenesis, and increased production of the HF-IP guardian, α-MSH. Crucially, ex vivo, rhIL-15 prevented IFNγ-induced HF-IP collapse, restored a collapsed HF-IP by IL-15Rα-dependent signaling (as documented by IL-15Rα−silencing), and protected AA-preventive immunoinhibitory iNKT10 cells from IFNγ-induced apoptosis. rhIL-15 even promoted hair regrowth after experimental AA induction in human scalp skin xenotransplants on SCID/beige mice in vivo. Our data introduce IL-15 as a novel, functionally important HF-IP guardian whose signaling is constitutively defective in scalp HFs of AA patients. Our data suggest that selective stimulation of intrafollicular IL-15Rα signaling could become a novel therapeutic approach in AA management, while blocking it pharmacologically may hinder both HF-IP restoration and hair re-growth and may thus make HFs more vulnerable to AA relapse.

Immunolocalization of telomerases in human hairs identifies proliferating cells in the bulb matrix and outer root sheath

Telomerase is present in cells with numerous or even un-limited replicative cycles, and some studies suggest it is a stemness marker. In order to determine whether this is the case for the human hair bulbs, an immunohistochemical and ultrastructural study has been carried out using antibodies against telomerase and PCNA (a cell proliferation marker). The observed labeling is similar for the two antibodies here utilized and is mainly nuclear. More frequent telomerase-positive cells are seen in the matrix epithelium of anagen hair bulbs but sparse labeled cells are also seen in the outer root sheath. In late catagen and also in telogen hair follicles only sparse labeled cells are present in the outer root sheath and few cells also in the secondary germinal epithelium formed at the base of the hair bulb in telogen. Electron microscopic immunogold shows a prevalent nuclear distribution and a lower cytoplasmic distribution in sparse cells of anagen bulb matrix that contain few keratin bundles. The nuclear localization is generally seen over the euchromatin or in areas occupied by more compact chromatin that may indicate an activity of telomerase in chromatin assemblage or dis-assemblage. The study concludes that the localization of telomerase is present in cells undergoing proliferation, namely transit amplifying cells of the outer root sheath that are sparsely detected in the lowermost secondary germinal hair bulb also in telogen.

Investigating &lt;em&gt;Trichophyton violaceum&lt;/em&gt; Metabolites and their Effects &lt;em&gt;In Vivo&lt;/em&gt;

The common dermatophyte Trichophyton violaceum invades hair of the endothrix type by penetrating the cortex right above the hair bulb and surrounding the shaft below the undamaged cuticle. The current investigation aims to isolate and characterize secondary metabolites of T. violaceum and detect their effects In vivo. In this study, 52 (65%) out of 80 clinical specimens were positive for Trichophyton violaceum by both KOH 10% wet mount and culture. It has appeared that T. violaceum isolates can create a variety of secondary metabolites. Of these, one compound appeared in yellow with Rf. with a value of 14.2 cm in TLC plates compared to standard AFB1, named T. violaceum A (TVA) complex. The FTIR and GC-MS chromatography showed several possibilities for analyzing such secondary metabolites, but the most acceptable possibility is that the compound (TVA) may be acidic. The macroscopic and microscopic examination of rat skin sections showed pathological changes after three weeks of subcutaneous injection with this compound. This study represents the first study about the production of mycotoxins from T. violaceum.