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.

Comparative study of melasma in patients before and after treatment based on lipomics.

BACKGROUND: Skin barrier alterations play a crucial function in melasma development. Past researches have demonstrated variations in lipid content between the epidermis of melasma lesions and normal tissues, along with the varied expression of lipid-related genes in melasma. This study aimed to analyze the lipidome profiles of skin surface lipids (SSL) in patients with melasma before and after treatment to understand associated abnormalities. METHODS: Melasma was treated with tranexamic acid orally and hydroquinone cream topically. Disease was assessed using the Melasma Area and Severity Index (MASI), and the impact to life was evaluated with Melasma Quality of Life (MELASQoL) score. Epidermal melanin particles were observed using reflection confocal microscopy (RCM), whereas epidermal pigment and blood vessel morphology were observed using dermoscopy, and SSL samples were collected. Specific information regarding alterations in lipid composition was obtained through multivariate analysis of the liquid chromatography-mass spectrometry data. RESULTS: After treatment, patients with melasma exhibited decreased MASI and MELASQoL scores (P < 0.001); RCM revealed reduced melanin content in the lesions, and dermoscopy revealed fewer blood vessels. Fifteen lipid subclasses and 382 lipid molecules were identified using lipidomic assays. The expression levels of total lipids, phosphatidylcholine, and phosphatidylethanolamine in the melasma lesions decreased after treatment (P < 0.05). CONCLUSION: This study revealed alterations in the SSL composition after effective melasma treatment, suggesting a compensatory role for lipids in melasma barrier function. The mechanism involving SSL and the lipid barrier, which influences melasma's occurrence, needs further elucidation.

The causal relationship between blood metabolites and rosacea: A Mendelian randomization.

BACKGROUND: An increasing amount of research demonstrates that metabolic disorders are related to rosacea. However, the correlations and causal relationships among them remain unknown. METHODS: We conducted not only forward 2-sample MR (Mendelian randomization) analyses but also reverse MR analyses which showed positive results in the forward MR analysis. In the forward MR analyses, inverse-variance weighted (IVW) and MR-Egger were performed as MR analyses. Cochran's Q test and the MR-Egger Intercept were used for sensitivity analyses. Concerning reverse MR analyses, IVW, MR-Egger, weighted median, simple mode, and weighted mode were applied. Cochran's Q test, MR-Egger Intercept, and MR pleiotropy residual sum and outlier (MR-PRESSO) outlier test were applied as sensitivity analyses. RESULTS: A total of 24 metabolites and 1 metabolite ratio were shown to have a causal effect on rosacea. N-lactoyl phenylalanine (N-Lac-Phe) was estimated as statistically significant by Bonferroni correction. Interestingly, we found three metabolites that were negatively associated with rosacea, especially caffeine, which are in line with the results of a large cohort study of females. For reverse MR analysis, we revealed that rosacea could potentially decrease the generation of two metabolites: octadecenedioate (C18:1-DC) and methyl vanillate sulfate. CONCLUSION: This study identified blood metabolites that may be associated with the development of rosacea. However, the exact mechanism by which these positive metabolites influence rosacea remains uncertain due to the paucity of experimental investigations. The combination of genetics and metabolomics offers novel viewpoints on the research of underlying mechanisms of rosacea and has significant value in screening and prevention of rosacea.

Causal role of immune cells in alopecia areata: A two-sample Mendelian randomization study.

BACKGROUND: Previous research has highlighted an association between alopecia areata (AA) and the collapse of hair follicle immune privilege, however, the causal linkage to specific immune cell traits remains to be elucidated. This study aimed to investigate the causal influence of immune cell traits on AA utilizing a two-sample Mendelian randomization (MR) approach. METHODS: Leveraging GWAS summary statistics of 731 immunological traits (n = 3757) and AA data (n = 211,428), MR analyses were conducted employing inverse-variance weighted (IVW), weighted median, and MR-Egger regression methodologies. Sensitivity analyses were undertaken using Cochran's Q test, MR-Egger intercept test, and MR-PRESSO analysis. A reverse MR analysis was performed for immune cell traits identified in the initial MR analysis. RESULTS: Our study unveiled multiple immune traits associated with AA. Protective associations were observed for CD62L- CD86+ myeloid dendritic cells (DCs), TD CD4+%CD4+ T cells, and others, with ORs ranging from 0.63 to 0.78. Conversely, traits like CD62L on CD62L+ plasmacytoid DCs, HLA-DR on CD14- CD16+ monocytes, HLA-DR on monocytes, and others, were determined to augment the risk of AA, with ORs ranging from 1.13 to 1.46. Reverse MR analysis signified a reduction in BAFF-R on IgD-CD24-B cells post-AA onset (OR: 0.97, 95% CI: 0.95-1.00), with no identified heterogeneity or horizontal pleiotropy among the instrumental variables (IVs). CONCLUSIONS: Our findings suggests that CD62L on certain subpopulations of DCs and HLA-DR on monocytes may epitomize risk factors for AA, offering potential therapeutic targets for alleviating AA.

Efficacy and safety of botulinum toxin A in the treatment of female pattern hair loss.

BACKGROUND: Female pattern hair loss (FPHL) is the most prevalent type of alopecia among adult women. Presently, topical minoxidil stands as the sole treatment endorsed by the FDA. Addressing cases of FPHL in individuals who develop contact dermatitis in response to minoxidil can pose a challenge for dermatologists. OBJECTIVE: To assess the efficacy and safety of subcutaneous injections of Botulinum Toxin Type A (BTA) in treating FPHL. METHODS: Enrolled outpatients with FPHL who exhibited an allergic reaction to minoxidil solution. Diagnosis of FPHL was established through clinical examination and trichoscopy. Inclusion criteria involved patients with no prior treatment within the last year and without any comorbidities. BTA, specifically 100 units, was mixed with 2 mL of 0.9% normal saline. Twenty injection target sites, spaced 2-3 cm apart, were symmetrically marked on the hairless area of the scalp. A dosage of five units was intradermally injected at each target site. Representative photographs and dermoscopic images of the scalp were captured before and after 3 months of treatment. RESULTS: A total of 10 FPHL, aged between 26 and 40 years, were included. The average age was 30.3 ± 4.64 years, and all patients had a positive family history of Androgenetic Alopecia. The average duration of the disease was 3.70 ± 1.42 years. According to patients' self-assessment, after 1 month of treatment, 10 FPHL patients reported experiencing moderate to marked improvement in symptoms related to scalp oil secretion. Three months later, dermatological assessments showed that three had mild improvement, six had no change, and one had a worsening condition. No adverse effects were observed. CONCLUSIONS: Our study suggests that the effectiveness of BTA for FPHL is limited to 3 months. However, it can be considered for tentative use after effective communication with patients. The long-term efficacy and safety of BTA in treating FPHL require further observation and study.

Ultraviolet-induced red fluorescence in androgenetic alopecia-indicating alterations in microbial composition.

BACKGROUND: Ultraviolet (UV)-induced fluorescence technology is widely used in dermatology to identify microbial infections. Our clinical observations under an ultraviolet-induced fluorescent dermatoscope (UVFD) showed red fluorescence on the scalps of androgenetic alopecia (AGA) patients. In this study, based on the hypothesis that microbes are induced to emit red fluorescence under UV light, we aimed to explore the microbial disparities between the AGA fluorescent area (AF group) and AGA non-fluorescent area (ANF group). METHODS: Scalp swab samples were collected from 36 AGA patients, including both fluorescent and non-fluorescent areas. The bacterial communities on the scalp were analyzed by 16S rRNA gene sequencing and bioinformatics analysis, as well as through microbial culture methods. RESULTS: Significant variations were observed in microbial evenness, abundance composition, and functional predictions between fluorescent and non-fluorescent areas. Sequencing results highlighted significant differences in Cutibacterium abundance between these areas (34.06% and 21.36%, respectively; p < 0.05). Furthermore, cultured red fluorescent colonies primarily consisted of Cutibacterium spp., Cutibacterium acnes, Staphylococcus epidermidis, and Micrococcus spp. CONCLUSIONS: This is the first study to investigate scalp red fluorescence, highlighting microbial composition variability across different scalp regions. These findings may provide novel insights into the microbiological mechanisms of AGA.

Transient receptor potential mucolipin 1 circumvents oxidative stress in primary human melanocytes.

BACKGROUND: Transient Receptor Potential Mucolipin 1 (TRPML1) serves as a pivotal reactive oxygen species (ROS) sensor in cells, which is implicated in the regulation of autophagy. However, its function in melanocyte autophagy under oxidative stress remains elusive. METHODS: The expression and ion channel function of TRPML1 were investigated using immunofluorescence and calcium imaging in primary human melanocytes (MCs). After activating TRPML1 with MLSA1 (TRPML1 agonist), autophagy-related molecules were investigated via western blot. ROS level, apoptosis- and autophagy-related molecules were investigated after pretreatment with MLSA1. After interference with TRPML1 expression, mitochondrial structures were visualized by electron microscopy with hydrogen peroxide (H2O2）treatment. RESULTS: TRPML1 was expressed and functionally active in primary human MCs, and its activation promotes elevated expression of LC3-II and reduced apoptosis and ROS levels under oxidative stress. TRPML1 downregulation caused mitochondrial swelling and disruption of cristae structures under oxidative stress in primary human MCs. CONCLUSIONS: TRPML1 might mediate lysosomal autophagy in primary human MCs under oxidative stress, participating in mechanisms that maintain the oxidative and antioxidant systems in balance.

Definition of refractory melasma and its treatment: a review.

Although patients with refractory melasma have been treated using various methods, there is still no precise definition or summary of the therapies. To define refractory melasma and conduct a review of the treatments, we searched for relevant publications in PubMed, Web of Science, and the Cochrane Library, and a total of 35 references were obtained. Refractory melasma can be roughly defined as an ineffective treatment for melasma, including topical bleaching agents, chemical peels, laser therapy, microdermabrasion for more than six months, or chemical peels treated more than six times. Meanwhile, physicians should be careful when treating patients with darker skin and dermal or mixed types of melasma since these individuals do not respond well to treatment. Lasers combined with other methods, especially different types of lasers or topical agents, are considered more effective than monotherapy. Oral tranexamic acid (TXA) is a prospective cure for refractory melasma. Other methods include a combination of chemical peels, microneedling, or injections with additional therapies. In conclusion, we were able to provide a rough definition of refractory melasma and list the available therapies. According to the literature, the most prevalent treatment is laser combination therapy. However, laser treatment should be considered only after topical agents and chemical peeling have failed. Considering its side effects, efficacy, and safety, oral TXA may be a better option, but more research is needed to make a firm conclusion. Moreover, maintenance therapy is required after treatment.

DCUN1D1, a new molecule involved in depigmentation via upregulating CXCL10.

CD8+ T cells in the lesioned site play a crucial role in the pathogenesis of vitiligo. The chemokine CXCL10 secreted by keratinocytes regulates the migration of CD8+ T cells into the skin. In our previous study, we found that DCUN1D1 expression in vitiligo lesions positively correlates with Cxcl10 expression. In this study, the regulatory effect of DCUN1D1 on CXCL10 and cell function was investigated. DCUN1D1 protein expression was significantly higher in the skin tissue from vitiligo lesions compared with samples from healthy controls. High expression of DCUN1D1 in keratinocytes caused local hair depigmentation in mice, reduced melanin content, high infiltration of CD8+ T cells and increased CXCL10 expression. This suggested that DCUN1D1 may regulate CD8+ T-cell infiltration and depigmentation through CXCL10. Inhibition of DCUN1D1 expression in HaCaT cells abolished the IFN-γ-induced upregulation of p-JAK1, p-STAT1 and CXCL10, suppressed the H2 O2 -induced ROS generation and apoptosis, and upregulated tyrosinase expression in melanocytes. Collectively, these results show that DCUN1D1 is an important regulator of CXCL10 and may be a new target for the treatment of vitiligo.

Tranexamic acid may promote melanocores clustering in keratinocytes through upregulation of Rab5b.

Tranexamic acid (TXA) is a promising therapeutic agent in melasma that can act on multiple pathophysiologic mechanisms of melasma. However, it is unclear whether TXA affects melanin in keratinocytes. To explore the effect of TXA on melanocores in keratinocytes. The melanocore-incorporated keratinocytes were constructed by co-incubating normal human epidermal keratinocytes (NHEK) with melanocores. After being treated with TXA, autophagy- and melanin-related protein expressions were detected. Then, transcriptome sequencing was used to compare the genetic changes in melanocore-incorporated keratinocytes before and after TXA treatment and further verified the differentially expressed genes. At the same time, the distribution of melanocores in human keratinocytes was observed by transmission electron microscopy. We found that TXA does not promote melanin degradation in primary keratinocytes by inducing autophagy. Protein transport and intracellular protein transport-related genes were enriched after TXA treatment, and Rab5b was significantly upregulated. Transmission electron microscopy showed that the percentage of melanocores distributed in clusters increased after treatment with TXA, which was reduced after Rab5b silencing. In addition, results suggested that melanocores could colocalize with Rab5b and lysosome-associated membrane protein1 (LAMP1). Our study found that Rab5b may be involved in the melanocore distribution in keratinocytes. TXA may promote the clustering distribution of endocytic melanocores through upregulation of Rab5b, representing a potential mechanism of TXA treatment against melasma.

Efficacy and safety of picosecond laser for the treatment of melasma: a systematic review and meta-analysis.

Multiple laser modalities have been used for melasma treatment. However, the effectiveness of picosecond laser in treating melasma remains unclear. This meta-analysis investigated the effectiveness and safety of picosecond laser for melasma treatment. Randomized controlled trials (RCTs) comparing picosecond laser with conventional treatment for melasma were searched through five databases. The melasma area severity index (MASI)/modified MASI (mMASI) was used to quantify the degree of melasma improvement. Standardized mean differences and 95% confidence intervals were calculated using Review Manager for result standardization. Six RCTs, which used picosecond laser at 1064, 755, 595, and 532 nm wavelengths, were included herein. Picosecond laser significantly reduced the MASI/mMASI, but the results were highly heterogeneous (P = 0.008, I2 = 70%). In the subgroup analysis of 1064 and 755 nm picosecond lasers, 1064 nm picosecond laser significantly reduced the MASI/mMASI with no significant side effects (P = 0.04). Meanwhile, 755 nm picosecond laser did not significantly improve the MASI/mMASI compared with topical hypopigmentation agents (P = 0.08) and caused post-inflammatory hyperpigmentation. Other laser wavelengths could not be used in the subgroup analysis owing to an insufficient sample size. Picosecond laser at 1064 nm is safe and effective for melasma treatment. Picosecond laser at 755 nm is not superior to topical hypopigmentation agents in treating melasma. The exact efficacy of other wavelengths of picosecond laser for melasma treatment remains to be verified in large-scale RCTs.

The Efficacy of Fractional Carbon Dioxide Laser in Surgical Scars Treatment: A system Review and Meta-analysis.

BACKGROUND: Surgical scars seriously affect a patient's quality of life, and they have a strong impact on individuals. Many studies have reported the results of using fractional carbon dioxide (CO2) laser to treat surgical scars and have generally found it to be effective. OBJECTIVES: We conducted a meta-analysis with the objective of evaluating and proving the efficacy of fractional CO2 laser therapy for surgical scars. METHODS: We performed a search of databases including PubMed, Web of Science, Embase and the Cochrane Library. The outcomes of the meta-analysis were overall scores on the Vancouver Scar Scale (VSS) and its four dimensions (pigmentation, vascularity, pliability and height). Statistical analysis was performed using RevMan 5.4 software. RESULTS: A total of ten studies were included in this meta-analysis, including six randomized controlled trials (RCTs) and four nonrandomized controlled trials (N-RCTs). In the meta-analysis of RCTs and N-RCTs, similar results were obtained, and fractional CO2 laser irradiation significantly decreased VSS scores (P < 0.00001). In addition, fractional CO2 laser irradiation also had a significant effect on scores on the pigmentation (P = 0.08), vascularity (P = 0.001), flexibility (P = 0.005) and height (P = 0.008) dimensions. Except for mild pain during treatment and temporary erythema after treatment, most patients had no obvious adverse reactions. CONCLUSION: Our study found that fractional CO2 laser exhibits excellent efficacy and safety in terms of surgical scar treatment. Thus, we hope it becomes more widely available to patients with surgical scars. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors   www.springer.com/00266 .

Efficacy and safety of laser-assisted delivery of tranexamic acid for the treatment of melasma: a systematic review and meta­analysis.

Laser-assisted drug delivery (LADD) is a new treatment for delivering drugs within the skin. This meta-analysis investigates the effectiveness and safety of the laser-assisted delivery of tranexamic acid (TXA) to treat melasma. A literature review was conducted by searching publication platforms to search for randomized controlled trials (RCTs) that compared laser-assisted delivery of TXA with laser-alone or topical TXA-alone treatment. The Embase, Web of Science, PubMed, Google Scholar, and Cochrane Library databases were searched, and Melasma Area Severity Index (MASI)/modified MASI (mMASI) scores used as the clinical improvement outcomes. All statistical analyses were performed using the RevMan software (Review Manager, V.5.3). The standardized mean differences and 95% confidence intervals were used to assess the results. Five RCTs were included in this meta-analysis. These studies used ablative fractional photothermolysis and nonablative dermal remodeling laser modalities. The results showed that both laser modalities combined with TXA significantly decreased the MASI/mMASI scores (P = .0003). Furthermore, no serious adverse events were observed, except mild erythema and burning pain. The meta-analysis found that the laser-assisted delivery of TXA is a new effective and safe treatment option for melasma treatment.

The multi-target mechanism of Cyclosporin A in the treatment of vitiligo based on network pharmacology.

Network pharmacology is an emerging discipline that designs drugs based on systems biology theory and biological system network analysis. Here, we applied network pharmacology to analyze the multi-target mechanism of Cyclosporin A in the treatment of vitiligo First, we predicted the targets of Cyclosporin A. Second, we obtained the genes related to vitiligo from the database. Third, we constructed the PPI network of the mutual genes between Cyclosporin A and vitiligo and used gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) to analyze. Finally, we verified the prediction of potential targets through a docking study with Cyclosporin A. We found that there were 15 shared target genes between Cyclosporin A and vitiligo. We analyzed these 15 genes by Cytoscape and obtained a network diagram of 885 nodes. Through screening and molecular docking, PRKDC, CUL7, CUL1, HSPA8, HSPA4, and SIRT7 were the most likely multi-target mechanism of Cyclosporin A in the treatment of vitiligo. In our study, Cyclosporin A might not only affect the repair of DNA strands by targeting PRKDC, but also affected the innate and adaptive immune function of vitiligo patients by the targets of CUL1, CUL7, and HSP70. In addition, Cyclosporin A might promote the repigmentation of vitiligo by adjusting the expression of SIRT7.

Differences in the skin microbial community between patients with active and stable vitiligo based on 16S rRNA gene sequencing.

BACKGROUND/OBJECTIVE: Recent studies have described an association between altered skin microbial community and epidemiology of skin diseases, such as vitiligo, atopic dermatitis and psoriasis. In this study, we conducted microbiological analysis on patients at different stages of vitiligo to determine whether the dysbiosis is associated with disease progression. METHODS: To characterise the skin microbes in vitiligo patients, we profiled samples collected from 40 patients with active and stable vitiligo using the Novaseq sequencer. Alpha diversity was used to measure richness and uniformity, while Beta diversity (Non-Metric Multi-Dimensional Scaling) analysis was used to show the differences. Moreover, the species differences were evaluated by LEfSe analysis and the flora gene function was predicted using Statistical Analysis of Metagenomic Profiles (STAMP). RESULTS: The alpha diversity results showed no significant differences between active vitiligo and stable vitiligo, while beta diversity and LEfSe analysis results showed the differences in community composition. Streptomyces and Streptococcus were enriched in active vitiligo compared to stable vitiligo. In addition, the flora gene function of mixed acid fermentation was more pronounced in active vitiligo, while the function of lipid IVA biosynthesis was more significant in stable vitiligo. CONCLUSION: This study has shown the differences in epidermal microbes between active vitiligo and stable vitiligo. Our results suggest that maintaining the flora balance might be a potential therapeutic target for vitiligo.

The multi-targets mechanism of hydroxychloroquine in the treatment of systemic lupus erythematosus based on network pharmacology.

BACKGROUND: Network pharmacology is used with bioinformatic tools to broaden the understanding of drugs' potential targets and the intersections with key genes of particular disease. Here we applied network pharmacology to collect testable hypotheses about the multi-targets mechanism of hydroxychloroquine (HCQ) against systemic lupus erythematosus (SLE). METHODS: Firstly, we predicted the potential targets of HCQ. Secondly, we got the related genes of SLE returned from databases. Thirdly, the intersections of the potential targets (HCQ) and related genes (SLE) were analyzed with gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Finally, we validated our predictions of the potential targets by performing docking studies with HCQ. RESULTS: The results suggest that the efficacy of HCQ against SLE is mainly associated with the targets of cyclin-dependent kinase 2 (CDK2), estrogen receptor alpha (ESR1) and CDK1, which regulate PI3K/Akt/GSK3ß as well as interferon (IFN) signaling pathway. Biological process of the network associated with the three targets is concentrated in the inhibition of immune response, negative regulation of gene expression and regulation of immune system process. Molecular docking analysis proves that hydrogen bonding and π-π stacking are the main forms of interaction. CONCLUSIONS: Our research provides protein targets affected by HCQ in the treatment of SLE. Three key targets (CDK2, ESR1 and CDK1) involving 1766 proteins become the multi-targets mechanism of HCQ in the treatment of SLE. As well, the research also provides a new idea for introducing network pharmacology into the evaluation of the drugs with multi-targets in dermatology.

Melanocyte activation and skin barrier disruption induced in melasma patients after 1064 nm Nd:YAG laser treatment.

Melasma is a frequently acquired hyperpigmentary skin disorder, for which several therapies are available. Among them, 1064 nm QS Nd:YAG laser therapy is an effective method, but the recurrence rate of laser treatment is still high. The aim of the present study was to elucidate the mechanism of the high relapse rate of melasma after 1064 nm Nd:YAG laser treatment. Twenty-five female melasma patients were treated with 1064 nm Nd:YAG laser for 10 times. The lesional skin and non-lesional skin were evaluated by means of a reflectance confocal laser scanning microscope before and after laser treatment. Melanin content and transepidermal water loss (TEWL) were measured by an MPA9 skin multifunction tester accordingly. The melanin index value was significantly decreased in the lesional skin after laser treatment, while the non-lesional skin had no difference. The dendritic cells were observed at the level of the dermal-epidermal junction (DEJ) in the lesions of 8 patients before laser treatment, while after laser treatment, the dendritic cells were observed in all 25 subjects. Moreover, there was significant difference between the TEWL value of the lesions before and after laser treatment. Furthermore, the TEWL value was higher in lesions of the 8 subjects which had dendritic cells compared with other 17 subjects which had no dendritic cells, no matter before or after laser treatment. The relapse patients of melasma had higher TEWL value compared with the non-relapse patients. Melanocyte activation and skin barrier disruption may be related to the high relapse rate of melasma after laser treatment.