Dissecting hair breakage in alopecia areata: the central role of dysregulated cysteine homeostasis.

In the initial stages of Alopecia Areata (AA), the predominance of hair breakage or exclamation mark hairs serves as vital indicators of disease activity. These signs are non-invasive and are commonly employed in dermatoscopic examinations. Despite their clinical salience, the underlying etiology precipitating this hair breakage remains largely uncharted territory. Our exhaustive review of the existing literature points to a pivotal role for cysteine-a key amino acid central to hair growth-in these mechanisms. This review will probe and deliberate upon the implications of aberrant cysteine metabolism in the pathogenesis of AA. It will examine the potential intersections of cysteine metabolism with autophagy, ferroptosis, immunity, and psychiatric manifestations associated with AA. Such exploration could illuminate new facets of the disease's pathophysiology, potentially paving the way for innovative therapeutic strategies.

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-ß (TGF-ß), 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/ß-catenin pathway (e.g., dickkopf 1 (DKK1)). Here, we summarize the commonalities and differences between AA and vitiligo, focusing on their pathogenesis.

Restoration of Immune Privilege in Human Dermal Papillae Controlling Epithelial-Mesenchymal Interactions in Hair Formation.

BACKGROUND: Hair follicles are among a handful of organs that exhibit immune privilege. Dysfunction of the hair follicle immune system underlies the development of inflammatory diseases, such as alopecia areata. METHODS: Quantitative reverse transcription PCR and immunostaining was used to confirm the expression of major histocompatibility complex class I in human dermal papilla cells. Through transcriptomic analyses of human keratinocyte stem cells, major histocompatibility complex class I was identified as differentially expressed genes. Organ culture and patch assay were performed to assess the ability of WNT3a conditioned media to rescue immune privilege. Lastly, CD8+ T cells were detected near the hair bulb in alopecia areata patients through immunohistochemistry. RESULTS: Inflammatory factors such as tumor necrosis factor alpha and interferon gamma were verified to induce the expression of major histocompatibility complex class I proteins in dermal papilla cells. Additionally, loss of immune privilege of hair follicles was rescued following treatment with conditioned media from outer root sheath cells. Transcriptomic analyses found 58 up-regulated genes and 183 down-regulated genes related in MHC class I+ cells. Using newborn hair patch assay, we demonstrated that WNT3a conditioned media with epidermal growth factor can restore hair growth. In alopecia areata patients, CD8+ T cells were increased during the transition from mid-anagen to late catagen. CONCLUSION: Identification of mechanisms governing epithelial and mesenchymal interactions of the hair follicle facilitates an improved understanding of the regulation of hair follicle immune privilege.

Reversal of alopecia areata, osteoporosis follow treatment with activation of Tgr5 in mice.

BACKGROUND: Alopecia areata is an autoimmune hair loss disease with infiltration of pro-inflammatory cells into hair follicles. The role of Tgr5 in dermatitis has attracted considerable attention. The present study aimed to investigate the effect of Tgr5 in the development of Alopecia areata. METHODS: The study utilized a comparison control group design with four groups of wild-type group, wild-type+INT777 group, Tgr5-/- group, and Tgr5-/-+INT777 group. The mice were treated with INT777 (30 mg/kg/day) or the carrier solution (DMSO) intraperitoneally for 7 weeks, and the back skin was collected and analyzed by histology and immunohistochemistry staining. The lumbar vertebrae 4 has also been analyzed by DXA and Micro-CT. RESULTS: Tgr5-/- mice displayed the decreasingly significant in hair area and length, skin thickness, and the ratio of anagen and telogen, collagen, and mast cell number and loss the bone mass than WT group. After treating with INT777, the appearance of alopecia areata and bone microstructure has improved. Immunohistochemistry and qPCR analysis showed that activation of Tgr5 can down-regulate the express of JAK1, STAT3, IL-6, TNF-α, and VEGF. CONCLUSION: These findings indicate that activation of Tgr5 mediated amelioration of alopecia areata and osteoporosis by down-regulated JAK1-STAT3 signaling pathway.

Mesenchymal Stem Cells Antagonize IFN-Induced Proinflammatory Changes and Growth Inhibition Effects via Wnt/ß-Catenin and JAK/STAT Pathway in Human Outer Root Sheath Cells and Hair Follicles.

Mesenchymal stem cell therapy (MSCT) has been shown to be a new therapeutic option for treating alopecia areata (AA). Outer root sheath cells (ORSCs) play key roles in maintaining the hair follicle structure and supporting the bulge area. In human ORSCs (hORSCs), the mechanism for this process has not been extensively studied. In this study, we aimed to examine the influence of human hematopoietic mesenchymal stem cells (hHMSCs) in the hORSCs in vitro model of AA and determine the mechanisms controlling efficacy. Interferon-gamma (IFN-γ) pretreatment was used to induce an in vitro model of AA in hORSCs. The effect of MSCT on the viability and migration of hORSCs was examined using co-cultures, the MTT assay, and migration assays. We investigated the expression of molecules related to the Wnt/ß-catenin pathway, JAK/STAT pathway, and growth factors in hHMSC-treated hORSCs by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses. hHMSCs increased hORSC viability and migration when they were co-cultured. hHMSCs reverted IFN-γ-induced expression-including NLRP3, ASC, caspase-1, CXCL-9 through 11, IL-1ß, and IL-15-and upregulated several growth factors and hair stem cell markers. hHMSCs activated several molecules in the Wnt/ß-catenin signaling pathway, such as in the Wnt families, ß-catenin, phosphorylated GSK-3ß and cyclin D1, and suppressed the expression of DKK1 induced by IFN-γ in hORSCs. hHMSCs suppressed the phosphorylation of JAK1 to 3, STAT1, and STAT3 compared to the controls and IFN-γ-pretreated hORSCs. These results demonstrate that hHMSCs increased hORSC viability and migration in the in vitro AA model. Additionally, MSCT definitely stimulated anagen survival and hair growth in an HF organ culture model. MSCT appeared to be associated with the Wnt/ß-catenin and JAK/STAT pathways in hORSCs.

Selective inhibition of JAK3 signaling is sufficient to reverse alopecia areata.

The Janus kinase/signal transducers and activators of transcription (JAK/STAT) are key intracellular mediators in the signal transduction of many cytokines and growth factors. Common γ chain cytokines and interferon-γ that use the JAK/STAT pathway to induce biological responses have been implicated in the pathogenesis of alopecia areata (AA), a T cell-mediated autoimmune disease of the hair follicle. We previously showed that therapeutic targeting of JAK/STAT pathways using the first-generation JAK1/2 inhibitor, ruxolitinib, and the pan-JAK inhibitor, tofacitinib, was highly effective in the treatment of human AA, as well as prevention and reversal of AA in the C3H/HeJ mouse model. To better define the role of individual JAKs in the pathogenesis of AA, in this study, we tested and compared the efficacy of several next-generation JAK-selective inhibitors in the C3H/HeJ mouse model of AA, using both systemic and topical delivery. We found that JAK1-selective inhibitors as well as JAK3-selective inhibitors robustly induced hair regrowth and decreased AA-associated inflammation, whereas several JAK2-selective inhibitors failed to restore hair growth in treated C3H/HeJ mice with AA. Unlike JAK1, which is broadly expressed in many tissues, JAK3 expression is largely restricted to hematopoietic cells. Our study demonstrates inhibiting JAK3 signaling is sufficient to prevent and reverse disease in the preclinical model of AA.

Myeloid Adherent Cells Are Involved in Hair Loss in the Alopecia Areata Mouse Model.

Alopecia areata (AA), which is defined as an autoimmune hair loss disease, has a serious impact on the quality of life for patients with AA worldwide. In this study, to our knowledge, a previously unreported method of AA induction in C3H mice has been established and validated. Using this method, we showed that dermal injection of 1-3 million of a mixture of skin cells freshly isolated from AA-affected skin induces AA in more than 80% of healthy mice. Contrary to the previous protocol, the induction of AA by this approach does not need any surgical AA skin grafting, cell manipulation, or high number of activated T cells. We also showed that dermal injection of adherent myeloid cells (mainly CD11b+) in healthy mice is as potent as a mixture of none adherent CD3+ T cells and CD19+ B cells in the induction of AA. Interestingly, most of the mice (7 out of 8) that received non-adherent cells developed AA universalis, whereas most of the mice (5 out of 7) that received adherent cells developed patchy AA. Finally, we found a high number of stage-specific embryonic antigen-expressing cells whose expression in monocytes in an inflammatory disease causes the release of inflammatory cytokines, TNF-α and IL-1ß, from these cells in AA-affected skin.

Understanding the significance of cytokines and chemokines in the pathogenesis of alopecia areata.

Alopecia areata has basically been understood as a type 1 inflammatory disease. Activated NKG2D+ CD8+ cells produce the Th1 cytokine interferon-γ, which leads to the disruption of immune tolerance of hair follicles and the exposure of self-antigens. This results in dense inflammatory cell infiltration and apoptosis around hair follicles, inducing hair loss. A well-known complication of alopecia areata is atopic dermatitis, a typical type 2 inflammatory disease. Hair scientists have shied away from confronting and understanding how alopecia areata, a type 1 inflammatory disease, and atopic dermatitis, a type 2 inflammatory disease, can occur together. This review summarizes the research on the cytokine balance in alopecia areata and then focuses on the classification of the cytokine balance in alopecia areata, including the classification of atopic dermatitis into extrinsic and intrinsic types. Dupilumab reportedly showed dual efficacy in a patient with concomitant atopic dermatitis and alopecia areata, supporting our own experience. Elevated Th2 cytokine levels have also been reported in patients with alopecia areata, with increased serum IL-4, IL-5, IL-6 levels, high IgE levels and elevated eosinophil levels. Because local immunotherapy is a treatment that induces Th2-type inflammation, it may worsen the condition of alopecia areata patients with extrinsic atopic dermatitis. It is desirable to select appropriate treatments with consideration of the cytokine balance.

Expression of CD117 and platelet-derived growth factor receptor α in patients with alopecia areata.

BACKGROUND: Alopecia areata is a disease of uncertain, probably autoimmune etiology. The role of growth factors like platelet-derived growth factor and C-kit (CD117) in alopecia areata is unknown. AIMS: To compare the expression of CD117 and platelet-derived growth factor receptor α in tissue samples of alopecia areata and normal controls. METHODS: Thirty biopsy samples of alopecia areata and eighteen normal control samples were included in this cross-sectional study. Immunohistochemistry was done to detect the expression of CD117 and platelet-derived growth factor receptor α in cases and controls. The mean percentage of follicles expressing CD117 and platelet-derived growth factor receptor α was compared among cases and controls. RESULTS: The mean number of follicles expressing CD117 in anagen and catagen hairs differed significantly among cases and controls. The extent and intensity of staining with platelet-derived growth factor receptor α correlated significantly with the severity of alopecia areata based on the severity of alopecia tool score. LIMITATIONS: Confirmation of the expression pattern of molecules observed in immunohistochemistry with western blot or polymerase chain reaction would have strengthened the report. CONCLUSIONS: The expression of CD117 varied in cases and controls. The expression of platelet-derived growth factor receptor α correlated with the severity of the disease. This could explain how platelet-rich plasma works in the treatment of alopecia areata. Further studies are required to explore the role of these molecules in autoimmune pathogenesis.

Local secretion of stress hormones increases in alopecia areata lesions after treatment with UVA-1 phototherapy.

Alopecia areata (AA) is an autoimmune disease of the hair follicle. Keratinocytes of the hair follicle generate an immunosuppressive environment by the local secretion of hormones of the hypothalamic-pituitary-adrenal axis of the skin (skin HPA analog). Our objective was to measure the local production of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and α-melanocyte-stimulating hormone (α-MSH) in the scalp tissue of patients with AA before and after ultraviolet A1 (UVA-1) phototherapy to determine their role in the pathogenesis of AA and the effect of UVA-1 on the AA hormonal environment. This was a retrospective and descriptive study of skin samples from 22 patients with AA before and after UVA-1 treatment. We compared the changes in the local hormonal environment by measuring CRH, ACTH, type 2 melanocortin receptor (ACTH receptor) and α-MSH with immunohistochemical stains. The positivity of MSH was significantly higher (P = .037) in the post-treatment samples compared with the baseline value. ACTH was significantly higher in intensity (P = .032) in the post-treatment samples compared with the initial value. CRH was significantly higher in intensity (P = .013) in baseline samples compared with the final biopsies. The positivity of the ACTH receptor MC2R was not different between the two groups (P = .626). In AA, an interruption in the signalling of CRH could decrease the local concentration of ACTH and MSH, and consequently, the immunosuppressive effect of these hormones. This phenomenon is normalized in the skin treated with UVA-1. A defective signalling system in the cutaneous HPA axis may be involved in the pathogenesis of AA.

Increased expression of TLR7 and TLR9 in alopecia areata.

Alopecia areata (AA) is thought to be an autoimmune process. In other autoimmune diseases, the innate immune system and Toll-like receptors (TLRs) can play a significant role. Expression of TLR7, TLR9 and associated inducible genes was evaluated by quantitative PCR in peripheral blood mononuclear cells (PBMCs) from 10 healthy individuals and 19 AA patients, categorized according to disease duration, activity and hair loss extent. Microdissected scalp biopsies from five patients and four controls were also assessed by quantitative PCR and immunohistology. TLR9 was significantly upregulated 2.37 fold in AA PBMCs. Notably, TLR9 was most significantly upregulated in patients with active AA, as shown by a positive hair pull test, compared to stable AA patients. In hair follicle bulbs from AA patients, IFNG and TLR7 exhibited statistically significant 3.85 and 2.70 fold increases in mRNA, respectively. Immunohistology revealed TLR7 present in lesional follicles, while TLR9 positive cells were primarily observed peri-bulbar to AA affected hair follicles. The increased expression of TLR7 and TLR9 suggest components of the innate immune system may be active in AA pathogenesis.

Distinguishing immunohistochemical features of alopecia areata from androgenic alopecia.

BACKGROUND: Distinction between alopecia areata (AA) and androgenic alopecia (AGA) can be made according to clinical presentation and biopsy findings. However, it is sometimes difficult to differentiate them, especially when the diffuse pattern of both AA and AGA is in the differential diagnosis of hair loss in androgen-dependent areas. OBJECTIVES: To evaluate the characteristics of inflammatory cell infiltration using CD3, CD4, CD8, and CD20 antigens, in AA and AGA to find some consistent histological clues for distinguishing these two entities. METHODS: A retrospective analysis of patients with diagnosed AA (30 cases) and AGA (30 cases) was performed based on the clinical and histopathological criteria. We studied immunohistochemical findings for CD3, CD4, CD8, and CD20 in all selected cases. RESULTS: Immunohistochemical stains for CD4 and CD20 were not helpful in differentiating AA from AGA, but the inflammation density for AA was significantly (P-value = .025, .001) higher than AGA in CD3 (specificity= 86.7% and sensitivity= 96.7%) and CD8 (specificity= 50% and sensitivity=86.6%). Our findings revealed that intrafollicular CD3 (P-value = .017) and CD8 (P-value = Ë‚.001) infiltrations were significantly higher in AA samples in comparison with AGA. CONCLUSION: Characterization of CD3 and CD8 in IHC samples is helpful, especially when the density of CD3 and CD8 T cells are significant in more than 50% of the infiltrated cells and are located intrafolliculary. Moreover, the most specific and sensitive test for differentiating of AA from AGA is CD3.

SOCS3 treatment prevents the development of alopecia areata by inhibiting CD8+ T cell-mediated autoimmune destruction.

Alopecia areata is one of the most common autoimmune diseases resulting from T cell-mediated damage of hair follicles. CD8+ T cells infiltrate hair follicles and are responsible for destruction of hair follicles. However the underlying mechanisms for hair loss remain still obscure. In the present study, we identified that suppressor of cytokine signaling-3 (SOCS3), a classical inhibitor of cytokine signaling, significantly inhibits CD8+T cell maturation, interferon-γ (IFN-γ) production and alopecia areata. SOCS3 is downregulated in the skin of alopecia areata patients and murine autoimmune alopecia model. Furthermore, SOCS3 treatment prevents the development of alopecia areata in the graft model. SOCS3 decreases the CD44high CD62Llow effector memory CD8+ T cells, resulting in the decrease of IFN-γ production. The expression of Fas and major histocompatibility complex-1 (MHC I) is upregulated in skin from C3H/HeJ alopecia areata mice, and this increase is suppressed by SOCS3. The SOCS3 level is negative correlation with the Fas and MHC I level in patients with alopecia areata. These results suggest that SOCS3 treatment may be an effective strategy to treat autoimmune alopecia as well as to more generally prevent cytokine-dependent tissue destruction in inflammatory diseases.

Nutrition and skin: Kids are not just little people.

There has been a surge of new data regarding the pathophysiology of skin diseases. We are appreciating the sophisticated interplay among the skin, the immune system, and the environment. More elegant and highly specific medicines have been designed to target certain immune mediators of the adaptive immune system. In parallel fashion, we are learning more about the elegance of the innate immune system and how nutrition as early as the prenatal period can affect the priming of other immune cells. Concerns about the long-term impact of new immune-modulating medicines-especially in the pediatric population-have patients asking their dermatologists for nutritional alternatives to medical therapies. Nutrients and nutritional therapies appear to play a role at different ages for different dermatoses. Probiotics are showing promise as a therapeutic option for patients older than 1 year for atopic dermatitis. Systemic contact allergens appear to be a bigger burden on the adult population with atopic dermatitis. Obesity is a growing concern for both children and adults with psoriasis. Milk and high glycemic foods have a strong impact on the teenage acne population. Vitamins A and D are addressed as piece of the alopecia areata puzzle. Zinc and homeopathy are presented finally as possible treatments to the everlasting wart.

Evaluation of macrophage migration inhibitory factor (MIF) levels in serum and lesional skin of patients with alopecia areata.

BACKGROUND: Alopecia areata (AA) is a non-scarring hair loss condition, the pathogenesis of which is not fully understood. Genetic predisposition, autoimmunity, and stress may each play a role. Macrophage migration inhibitory factor (MIF) is a cytokine that plays a role in the regulation of macrophage function. It also initiates inflammation and immune response by regulating a number of proinflammatory cytokines. OBJECTIVES: This study was designed to study serum and lesional skin biopsy MIF levels in AA patients and to assess their associations with disease severity. METHODS: This study included 30 patients with AA and 15 age- and sex-matched healthy control subjects. Quantitative measurements of MIF concentrations in sera and skin samples were obtained in both patients and control subjects. Associations with disease severity (assessed using the Severity of Alopecia Tool) were evaluated. RESULTS: Mean ± standard deviation (SD) MIF levels in serum and skin were significantly higher in AA patients (45.03 ± 26.98 ng/ml and 73.83 ± 29.81 ng/ml, respectively) than in controls (7.73 ± 1.62 ng/ml and 0.40 ± 1.12 ng/ml, respectively) (P < 0.01). Mean ± SD serum and skin MIF levels were also found to be higher in severe AA (69.93 ± 11.51 ng/ml and 100.80 ± 13.77 ng/ml, respectively) than in mild AA (20.13 ± 6.84 ng/ml and 46.87 ± 9.65 ng/ml, respectively) (P < 0.01). CONCLUSIONS: The finding that MIF is increased in serum and lesional skin of AA patients indicates its possible involvement in the pathogenesis of the disease.

Zinc and skin biology.

Of all tissues, the skin has the third highest abundance of zinc in the body. In the skin, the zinc concentration is higher in the epidermis than in the dermis, owing to a zinc requirement for the active proliferation and differentiation of epidermal keratinocytes. Here we review the dynamics and functions of zinc in the skin as well as skin disorders associated with zinc deficiency, zinc finger domain-containing proteins, and zinc transporters. Among skin disorders associated with zinc deficiency, acrodermatitis enteropathica is a disorder caused by mutations in the ZIP4 transporter and subsequent zinc deficiency. The triad acrodermatitis enteropathica is characterized by alopecia, diarrhea, and skin lesions in acral, periorificial, and anogenital areas. We highlight the underlying mechanism of the development of acrodermatitis because of zinc deficiency by describing our new findings. We also discuss the accumulating evidence on zinc deficiency in alopecia and necrolytic migratory erythema, which is typically associated with glucagonomas.

Biomarkers of alopecia areata disease activity and response to corticosteroid treatment.

Alopecia areata (AA) is a common inflammatory disease targeting the anagen-stage hair follicle. Different cytokines have been implicated in the disease profile, but their pathogenic role is not yet fully determined. We studied biopsies of pretreatment lesional and non-lesional (NL) scalp and post-treatment (intra-lesional steroid injection) lesional scalp of 6 patchy patients with AA using immunohistochemistry and gene expression analysis. Immunohistochemistry showed increases in CD3(+) , CD8(+) T cells, CD11c(+) dendritic cells and CD1a(+) Langerhans cells within and around hair follicles of pretreatment lesional scalp, which decreased upon treatment. qRT-PCR showed in pretreatment lesional scalp (compared to NL) significant increases (P < 0.05) in expression of inflammatory markers (IL-2, IL-2RA, JAK3, IL-15), Th1 (CXCL10 and CXCL9), Th2 (IL-13, CCL17 and CCL18), IL-12/IL-23p40 and IL-32. Among these, we observed significant downregulation with treatment in IL-12/IL-23p40, CCL18 and IL-32. We also observed significant downregulation of several hair keratins in lesional scalp, with significant upregulation of KRT35, KRT75 and KRT86 in post-treatment lesional scalp. This study shows concurrent activation of Th1 and Th2 immune axes as well as IL-23 and IL-32 cytokine pathways in lesional AA scalp and defined a series of response biomarkers to corticosteroid injection. Clinical trials with selective antagonists coupled with cytokine-pathway biomarkers will be necessary to further dissect pathogenic immunity.

Circumscribed cicatricial alopecia due to localized sarcoidal granulomas and single-organ granulomatous arteritis: a case report and systematic review of sarcoidal vasculitis.

Vasculitis associated with sarcoid granulomas is an uncommon phenomenon. A 72-year-old female presented with an expanding region of circumscribed alopecia and scalp atrophy of 2 months duration. Biopsy showed non-caseating granulomas, dermal thinning, loss of follicles, fibrosis and muscular vessels disrupted by mixed lymphocyte, macrophage and giant-cell infiltrates. Affected vessels had loss and fragmentation of the elastic lamina, fibrous replacement of their walls and luminal stenosis (endarteritis obliterans). Dermal and vascular advential intralymphatic granulomas and lymphangiectases were found by D2-40 expression, suggesting lymphatic obstruction and poor antigen clearance. No evidence of a post-zoster eruption, systemic sarcoidosis or systemic giant-cell arteritis was found. Two years later, prednisone had halted - but not reversed - progression of her alopecia. Review of the literature showed two types of vasculitis associated with sarcoid granulomas: (i) acute, self-limited leukocytoclastic vasculitis and (ii) chronic granulomatous vasculitis (GV). Persistence of non-degradable material or antigen contributes to the pathogenesis of granulomatous inflammation. In this case, lymphatic obstruction probably impeded clearance of nonimmunologic and/or immunologic stimuli permitting and sustaining the development of sarcoid granulomas and sarcoid GV, ultimately causing scarring alopecia and cutaneous atrophy.