Autoimmunity in vitiligo: Therapeutic implications and opportunities

The role of regulatory T cells in vitiligo and therapeutic advances: a mini-review

BACKGROUND

Regulatory T cells (Tregs) play vital roles in controlling immune reactions and maintaining immune tolerance in the body. The targeted destruction of epidermal melanocytes by activated CD8+T cells is a key event in the development of vitiligo. However, Tregs may exert immunosuppressive effects on CD8+T cells, which could be beneficial in treating vitiligo.

METHODS

A comprehensive search of PubMed and Web of Science was conducted to gather information on Tregs and vitiligo.

RESULTS

In vitiligo, there is a decrease in Treg numbers and impaired Treg functions, along with potential damage to Treg-related signaling pathways. Increasing Treg numbers and enhancing Treg function could lead to immunosuppressive effects on CD8+T cells. Recent research progress on Tregs in vitiligo has been summarized, highlighting various Treg-related therapies being investigated for clinical use. The current status of Treg-related therapeutic strategies and potential future directions for vitiligo treatment are also discussed.

CONCLUSIONS

A deeper understanding of Tregs will be crucial for advancing Treg-related drug discovery and treatment development in vitiligo.

From mice to men: An assessment of preclinical model systems for the study of vitiligo

Vitiligo is an autoimmune skin disease of multiple etiology, for which there is no complete cure. This chronic depigmentation is characterized by epidermal melanocyte loss, and causes disfigurement and significant psychosocial distress. Mouse models have been extensively employed to further our understanding of complex disease mechanisms in vitiligo, as well as to provide a preclinical platform for clinical interventional research on potential treatment strategies in humans. The current mouse models can be categorized into three groups: spontaneous mouse models, induced mouse models, and transgenic mice. Despite their limitations, these models allow us to understand the pathology processes of vitiligo at molecule, cell, tissue, organ, and system levels, and have been used to test prospective drugs. In this review, we comprehensively evaluate existing murine systems of vitiligo and elucidate their respective characteristics, aiming to offer a panorama for researchers to select the appropriate mouse models for their study.

The role of aryl hydrocarbon receptor in vitiligo: a review

Vitiligo is an acquired autoimmune dermatosis characterized by patchy skin depigmentation, causing significant psychological distress to the patients. Genetic susceptibility, environmental triggers, oxidative stress, and autoimmunity contribute to melanocyte destruction in vitiligo. Due to the diversity and complexity of pathogenesis, the combination of inhibiting melanocyte destruction and stimulating melanogenesis gives the best results in treating vitiligo. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that can regulate the expression of various downstream genes and play roles in cell differentiation, immune response, and physiological homeostasis maintenance. Recent studies suggested that AhR signaling pathway was downregulated in vitiligo. Activation of AhR pathway helps to activate antioxidant pathways, inhibit abnormal immunity response, and upregulate the melanogenesis gene, thereby protecting melanocytes from oxidative stress damage, controlling disease progression, and promoting lesion repigmentation. Here, we review the relevant literature and summarize the possible roles of the AhR signaling pathway in vitiligo pathogenesis and treatment, to further understand the links between the AhR and vitiligo, and provide new potential therapeutic strategies.

Management of the refractory vitiligo patient: current therapeutic strategies and future options

Vitiligo is an autoimmune disease that leads to disfiguring depigmented lesions of skin and mucosa. Although effective treatments are available for vitiligo, there are still some patients with poor responses to conventional treatment. Refractory vitiligo lesions are mostly located on exposed sites such as acral sites and lips, leading to significant life stress. Understanding the causes of refractory vitiligo and developing targeted treatments are essential to enhance vitiligo outcomes. In this review, we summarized recent treatment approaches and some potential methods for refractory vitiligo. Janus kinase inhibitors have shown efficacy in refractory vitiligo. A variety of surgical interventions and fractional carbon dioxide laser have been widely applied to combination therapies. Furthermore, melanocyte regeneration and activation therapies are potentially effective strategies. Patients with refractory vitiligo should be referred to psychological monitoring and interventions to reduce the potential pathogenic effects of chronic stress. Finally, methods for depigmentation and camouflage may be beneficial in achieving uniform skin color and improved quality of life. Our ultimate focus is to provide alternative options for refractory vitiligo and to bring inspiration to future research.

A triple combination of latanoprost, fractional CO2 laser, and platelet-rich plasma in localized vitiligo: A clinical and histopathologic study

BACKGROUND

Several treatment modalities are available for the treatment of vitiligo due to the lack of a uniformly effective therapy. Topical latanoprost 0.005% is an effective topical treatment. Fractional CO2 laser alone or combined with platelet-rich plasma (PRP) has been proposed as effective adjunctive therapies.

OBJECTIVES

We aimed to compare the efficacy of topical latanoprost 0.005% (Ioprost®, Orchidia, Egypt) combined with either add-on fractional CO2 laser or fractional CO2 -PRP versus topical latanoprost monotherapy in the treatment of localized stable vitiligo.

PATIENTS/METHODS

The study included 60 patients randomly assigned into three equal groups. Group A patients received topical latanoprost drops only. Group B patients received topical latanoprost drops and fractional CO2 laser sessions at 2-week interval for 3 months. Group C patients received topical latanoprost drops and fractional CO2 laser sessions combined with PRP at a 2-week interval for 3 months. The mean improvement score by the physician was calculated 4 months after the start of the study. Punch skin biopsies were obtained before treatment and 4 months from the beginning of the study and stained with H&E and HMB-45 antibody for evaluation of pigmentation.

RESULTS

Significant clinical improvement of vitiligo lesions with significant increase of re-pigmentation were reported in the three treated groups. Latanoprost in combination with fractional CO2 and PRP was associated with more significant therapeutic outcomes than either combined latanoprost and fractional CO2 or latanoprost alone.

CONCLUSION

Fractional CO2 laser-PRP enhances the therapeutic efficacy of latanoprost 0.005% in the treatment of localized stable vitiligo.

Application Effect of Comprehensive Noise Reduction Technology in Outpatients with Vitiligo: A Retrospective Study

OBJECTIVE

Noise is a kind of perceived public nuisance that is closely related to people's subjective feelings and lives. This study explores the clinical application effect of comprehensive noise reduction technology in outpatients with vitiligo.

METHODS

A total of 76 patients with vitiligo were selected in the Department of Dermatology at Baoding No. 2 Central Hospital from January 2020 to January 2021, as the control group (CG), receiving 5S management mode, and 80 patients with vitiligo from February 2021 to October 2022 were selected as the study group (SG), receiving comprehensive noise reduction technology combined with the 5S management mode for this retrospective study. The effects of different management modes on these patients were observed.

RESULTS

SG had higher nursing quality scores in service attitude, service initiative, communication skills, environmental management and item management and overtly a lower noise level than CG (all P < 0.001). The Hamilton Anxiety Scale (HAMA) scores of the two groups at the end of treatment were significantly lower than those on admission (P < 0.05), with SG showing a lower score than CG (P < 0.001). Correlation analysis showed that noise levels and HAMA scores had a positive correlation (r = 0.423, P < 0.001). Patients with negative feelings about medical treatment caused by various noise sources in SG were obviously less than those in CG (P < 0.05). Both the groups had a statistical difference in overall satisfaction (P < 0.05).

CONCLUSION

The investigation and data analysis demonstrated that comprehensive noise reduction in outpatients with vitiligo had a considerable effect. This technology can standardise the behaviour of medical staff, enhance nursing quality, reduce noise levels and alleviate patients' anxiety and improve their satisfaction. It has great benefits for the outpatient environment and patients.

In-depth study of Wood's lamp examination combined with reflective confocal laser scanning microscopy for the guidance of vitiligo staging and treatment

BACKGROUND

Both Wood's lamp and reflective confidential laser scanning microcopy are helpful for the diagnosis and treatment of vitiligo. However, there is few research that contains large samples and consistent observations.

AIMS

To analyze the characteristics of Wood's lamp images and reflectance confocal microscopy (RCM) images of vitiligo lesions and to evaluate their significance in vitiligo staging.

METHODS

We analyzed the characteristics of RCM images, Wood's lamp images, the vitiligo disease activity (VIDA) score, and clinical features to guide vitiligo staging and treatment.

RESULTS

The expert consensus based on the clinical features, VIDA score, Wood's lamp findings, and isomorphic response was consistent with the Wood's lamp findings (χ2  = 3.63, p > 0.05) and RCM findings (χ2  = 3.60, p > 0.05) in diagnosing vitiligo and assessing the disease stage. There was a correlation between the three lesion grades based on the Wood's lamp findings and the stage of vitiligo (p < 0.01). Lesions that appeared porcelain white under the Wood's lamp were in the slowly progressive stage; lesions that appeared gray-white or trichromatic under the Wood's lamp were in the rapidly progressive stage; lesions with clear borders under the Wood's lamp needed further analysis by RCM for the stage to be determined; lesions with blurred borders under the Wood's lamp were in the rapidly progressive stage; lesions that were visible under the naked eye and under the Wood's lamp were in the rapidly progressive stage.

CONCLUSION

The study demonstrates a reliable correlation between the findings of RCM (a sophisticated expensive tool) and Wood's lamp examination (a simple, readily available, inexpensive tool) in the assessment of the disease activity of vitiligo lesions.

Efficacy of using oral methotrexate with phototherapy in the treatment of vitiligo in comparison with single phototherapy treatment: A double-blinded randomized controlled trial

BACKGROUND

Vitiligo is an acquired skin disease with a worldwide prevalence of 0.5%-2% and a tendency to involve both genders. Although the exact pathologic mechanism is unknown, there is some evidence for the role of autoimmunity in this disease. Based on this theory, various immunosuppressive agents, such as topical or systemic corticosteroids and phototherapy (including narrowband ultraviolet B), are used. Methotrexate is another immunosuppressant that has recently become popular as a single treatment for vitiligo; however, the synergistic effect and its superiority over other treatments are two crucial factors that are still obscure. This study aimed to compare the efficacy of methotrexate+ NB-UVB versus placebo+ NB-UVB in vitiligo patients.

METHODS

In this double-blinded, randomized controlled trial, 42 patients were randomly allocated into two groups: the first group received three times weekly NB-UVB plus placebo, and the second group was treated with three times weekly NB-UVB in combination with a weekly dose of 12.5 mg MTX. The total duration of treatment was 6 months, patients were followed up every 2 months, and the assessment tools were VASI (repigmentation indicator) and VIDA (disease activity indicator) scores.

RESULTS

Both treatment groups showed improvement in VASI and VIDA scores during 6-month follow-up, but no statistical significance was found between the two treatment methods.

CONCLUSION

This study demonstrated that both treatment modalities were equally effective, and further studies are required to evaluate the efficacy of MTX with other medications with longer follow-up and a larger sample size.

Metagenomic sequencing reveals altered gut microbial compositions and gene functions in patients with non-segmental vitiligo

BACKGROUND

Vitiligo has been correlated with an abnormal gut microbiota. We aimed to systematically identify characteristics of the gut microbial compositions, genetic functions, and potential metabolic features in patients with non-segmental vitiligo.

METHODS

Twenty-five patients with non-segmental vitiligo and 25 matched healthy controls (HCs) were enrolled. Metagenomic sequencing and bioinformatic analysis were performed to determine the gut microbiota profiles. Differences in gut microbiota diversity and composition between patients with vitiligo and HCs were analyzed. Gene functions and gut metabolic modules were predicted with the Kyoto Encyclopedia of Gene and Genomes (KEGG) and MetaCyc databases.

RESULTS

Compared with HCs, alpha diversity of intestinal microbiome in vitiligo patients was significantly reduced. At the species level, the relative abundance of Staphylococcus thermophiles was decreased, and that of Bacteroides fragilis was increased in patients with vitiligo compared with those of the HCs. Linear discriminant analysis (LDA) effect size (LEfSe) analysis revealed representative microbial markers of Lachnospiraceae_bacterium_BX3, Massilioclostridium_coli, TM7_phylum_sp_oral_taxon_348 and Bacteroides_fragilis for patients with vitiligo. KEGG gene function analysis showed that the NOD-like receptor signaling pathway was significantly enriched in patients with vitiligo. Gut metabolic modules (GMMs) analysis showed that cysteine degradation was significantly down-regulated, and galactose degradation was up-regulated in patients with vitiligo. A panel of 28 microbial features was constructed to distinguish patients with vitiligo from HCs.

CONCLUSIONS

The gut microbial profiles and genetic functions of patients with vitiligo were distinct from those of the HCs. The identified gut microbial markers may potentially be used for earlier diagnosis and treatment targets.

Skin Pigmentation Types, Causes and Treatment-A Review

Human skin pigmentation and melanin synthesis are incredibly variable, and are impacted by genetics, UV exposure, and some drugs. Patients' physical appearance, psychological health, and social functioning are all impacted by a sizable number of skin conditions that cause pigmentary abnormalities. Hyperpigmentation, where pigment appears to overflow, and hypopigmentation, where pigment is reduced, are the two major classifications of skin pigmentation. Albinism, melasma, vitiligo, Addison's disease, and post-inflammatory hyperpigmentation, which can be brought on by eczema, acne vulgaris, and drug interactions, are the most common skin pigmentation disorders in clinical practice. Anti-inflammatory medications, antioxidants, and medications that inhibit tyrosinase, which prevents the production of melanin, are all possible treatments for pigmentation problems. Skin pigmentation can be treated orally and topically with medications, herbal remedies, and cosmetic products, but a doctor should always be consulted before beginning any new medicine or treatment plan. This review article explores the numerous types of pigmentation problems, their causes, and treatments, as well as the 25 plants, 4 marine species, and 17 topical and oral medications now on the market that have been clinically tested to treat skin diseases.

Silk Fibroin-Based Hydrogel Microneedles Deliver α-MSH to Promote Melanosome Delivery for Vitiligo Treatment

Microneedles have shown great advantages in subcutaneous drug delivery and skin disease treatment. Vitiligo is a difficult-to-cure skin disease characterized by the depigmentation of the epidermis. Melanosomes produced in melanocytes are transported through dendrites to adjacent keratinocytes, where they accumulate, resulting in skin pigmentation. However, melanocytes in vitiligo patients are functionally disrupted. Silk fibroin (SF) methacrylate hydrogel microneedle can deliver α-MSH to the epidermis directly, where α-MSH helps the protection of melanocytes, extension of melanocytic dendrites, and transfer of melanosomes. In addition, the expression of melanogenesis-related melanocyte-inducing transcription factor and tyrosinase-related protein 1 (TRP1) was up-regulated, and the number of hair follicle stem cells increased with good proliferative activity. This slow release α-MSH SF-based hydrogel microneedles provides a new idea for the treatment of vitiligo.

Ubiquitin-specific protease 34 in macrophages limits CD8 T cell-mediated onset of vitiligo in mice

As an autoimmune disorder, vitiligo is characterized by depigmented skin macules. CD8⁺T cells and macrophages enrichment promote the onset of vitiligo, while the role of macrophages to CD8⁺T is not well deciphered. To develop a mouse model of vitiligo with prominent epidermal depigmentation, Krt14-Kitl* transgenic mice containing an elevated number of melanocytes in the epidermis with membrane-bound Kit ligand (Kitl*) were adoptively transferred with premelanosome protein (PMEL) CD8⁺ T cells. On the other hand, Krt14-Kitl* mice were mated with ubiquitin-specific protease 34 (USP34)^MKO mice to decipher the role of USP34 in vitiligo. Vitiligo scores and PMEL CD8⁺ T cell enrichment were detected with flow cytometry. Human peripheral blood mononuclear cells (PBMCs) or mice bone marrow-derived macrophages (BMDMs) were incubated with lipopolysaccharide (LPS), CpG, or co-incubated with KU-55933, an ataxia telangiectasia-mutated (ATM) inhibitor. Chemokine (C-C motif) ligand 2 (CCL2), Ccl5, and interleukin (Il)-12α expression was assayed with real-time PCR, and p-IKKα/β was assayed with Western blots. USP34 was up-regulated in the PBMCs of vitiligo patients and LPS-stimulated BMDMs. USP34 deficiency did not affect the differentiation of CD11b⁺F4/80⁺ macrophages in the bone marrow. Immunoprecipitation demonstrated the interaction between USP34 and ATM. USP34 deficiency or KU-55933 administration promoted the induction of Ccl2, Ccl5, Il12α, and p-IKKα/β in LPS or CpG stimulated BMDMs; KU-55933 administration could not affect the expression of the above molecules in USP34 deficient BMDMs. It further revealed that USP34 deficiency promoted the development of vitiligo with increased PMEL CD8⁺ T cell enrichment, which was not affected by KU-55933 administration. USP34 deficiency in macrophages promotes the onset of vitiligo with increased PMEL CD8⁺ T cell enrichment, and USP34/ATM complex can be considered as a therapy target.

Ayurvedic Doctors Cannot Prescribe Allopathic Medicines-National Consumer Dispute Redressal Commission Judgement

Purvish M. ParikhWe describe the facts of the matter and the court's decision in a case of an Ayurveda, Yoga & Naturopathy, Unani, Siddha, and Homeopathy (AYUSH) doctor being found guilty of deficiency of service by prescribing allopathic medicines that were associated with known complications. The case details include the allegation, the defense, and the court's judgement. Details of the concerned acts, circulars, and regulations, as well as court case laws, are described. The regulations allow AYUSH doctors to prescribe allopathic medicines under certain circumstances, which were not adhered to in this case.

Management of Stable Vitiligo-A Review of the Surgical Approach

At present, vitiligo is the most common depigmenting skin disorder, characterized by clearly demarcated discolored patches of various shapes and sizes. Depigmentation results from the initial dysfunction and subsequent destruction of melanin-producing cells, called melanocytes, which are located in the basal layer of the epidermis and in hair follicles. This review concludes that the extent of repigmentation, regardless of the treatment method, is greatest in stable localized vitiligo patients. The aim of this review is to provide an overview of the clinical evidence for which the vitiligo treatment method (cellular or tissue) is more effective. The treatment relies on multiple factors, ranging from patient skin predisposition for repigmentation to the experience of the facility performing the procedure. Vitiligo is a significant problem in modern society. Although it is a typically asymptomatic and not life-threatening disease, it may have significant psychological and emotional impacts. Standard treatment relies on pharmacotherapy and phototherapy; however, the treatment of patients with stable vitiligo varies. The stability of vitiligo more than often implies the exhaustion of the potential for skin self-repigmentation. Thus, the surgical methods that distribute normal melanocytes into the skin are crucial elements of these patients' therapy. The most commonly used methods are described in the literature, with an indication of their recent progress and changes. In addition, information on the efficiency of the individual methods at specific locations is compiled in this study, and the prognostic factors indicating repigmentation are presented. Cellular methods are the best therapeutic option for large-sized lesions; although they are more exorbitant than tissue methods, they benefit from more rapid healing times and presenting fewer side effects. Dermoscopy is a valuable tool used to assess the further course of repigmentation, where it is of great value to evaluate the patient prior to and following an operation.

Contributions of NR1H3 genetic polymorphisms to susceptibility and effects of narrowband UVB phototherapy to nonsegmental vitiligo

Vitiligo is the most common depigmenting disorder to which both genetic and environmental factors contribute. The aim of the current work was to evaluate the relationship between polymorphisms of the gene nuclear receptor subfamily 1 Group H member 3 (NR1H3) and the risk of vitiligo and phototherapy effects in the Chinese Han population. Two independent samples were enrolled to form the discovery set (comprised of 1668 nonsegmental vitiligo [NSV] patients and 2542 controls) and the validation set (comprised of 745 NSV patients and 1492 controls). A total of 13 tag single nucleotide polymorphisms (SNPs) were genotyped in the samples from the discovery stage. SNPs that achieved nominal significance were validated in another independent sample set. The serum level of NR1H3 protein was assayed using enzyme-linked immunosorbent assay kits in the validation set. Genetic association analysis was carried out at allelic and genotypic levels. The therapeutic effects of significant SNPs were examined in the validation set. The SNP rs3758672 was significantly associated with NSV. The A allele was correlated with NSV risk and poorer therapeutic effects. The A allele was strongly correlated with the increased level of serum NR1H3 in both controls and patients. In summary, SNP rs3758672 in NR1H3 was significantly associated with both disease susceptibility and individualized therapeutic effects of NSV in study participants with Han Chinese ancestry.

Therapeutic potential of adipose tissue-derivatives in modern dermatology

Stem cell-mediated therapies in combination with biomaterial and growth factor-based approaches in regenerative medicine are rapidly evolving with increasing application beyond the dermatologic field. Adipose-derived stem cells (ADSCs) are the more frequently used adult stem cells due to their abundance and easy access. In the case of volumetric defects, adipose tissue can take the shape of defects, restoring the volume and enhancing the regeneration of receiving tissue. When regenerative purposes prevail on volume restoration, the stromal vascular fraction (SVF) rich in staminal cells, purified mesenchymal stem cells (MSCs) or their cell-free derivatives grafting are favoured. The therapeutic efficacy of acellular approaches is explained by the fact that a significant part of the natural propensity of stem cells to repair damaged tissue is ascribable to their secretory activity that combines mitogenic factors, cytokines, chemokines and extracellular matrix components. Therefore, the secretome's ability to modulate multiple targets simultaneously demonstrated preclinical and clinical efficacy in reversing pathological mechanisms of complex conditions such atopic dermatitis (AD), vitiligo, psoriasis, acne and Lichen sclerosus (LS), non-resolving wounds and alopecia. This review analysing both in vivo and in vitro models gives an overview of the clinical relevance of adipose tissue-derivatives such as autologous fat graft, stromal vascular fraction, purified stem cells and secretome for skin disorders application. Finally, we highlighted the major disease-specific limitations and the future perspective in this field.

Interleukin-6 cytokine: An overview of the immune regulation, immune dysregulation, and therapeutic approach

Several studies have shown that interleukin 6 (IL-6) is a multifunctional cytokine with both pro-inflammatory and anti-inflammatory activity, depending on the immune response context. Macrophages are among several cells that secrete IL-6, which they express upon activation by antigens, subsequently inducing fever and production of acute-phase proteins from the liver. Moreover, IL-6 induces the final maturation of B cells into memory B cells and plasma cells as well as an adaptive role for short-term energy allocation. Activation of IL-6 receptors results in the intracellular activation of the JAK/STAT pathway with resultant production of inflammatory cytokines. Several mechanisms-controlled IL-6 expression, but aberrant production was shown to be crucial in the pathogenesis of many diseases, which include autoimmune and chronic inflammatory diseases. IL-6 in combination with transforming growth factor β (TGF-β) induced differentiation of naïve T cells to Th17 cells, which is the cornerstone in autoimmune diseases. Recently, IL-6 secretion was shown to form the backbone of hypercytokinemia seen in the Coronavirus disease 2019 (COVID-19)-associated hyperinflammation and multiorgan failure. There are two classes of approved IL-6 inhibitors: anti-IL-6 receptor monoclonal antibodies (e.g., tocilizumab) and anti-IL-6 monoclonal antibodies (i.e., siltuximab). These drugs have been evaluated in patients with rheumatoid arthritis, juvenile idiopathic arthritis, cytokine release syndrome, and COVID-19 who have systemic inflammation. JAK/STAT pathway blockers were also successfully used in dampening IL-6 signal transduction. A better understanding of different mechanisms that modulate IL-6 expression will provide the much-needed solution with excellent safety and efficacy profiles for the treatment of autoimmune and inflammatory diseases in which IL-6 derives their pathogenesis.

The mosaic of autoimmunity - Finally discussing in person. The 13th international congress on autoimmunity 2022 (AUTO13) Athens

While autoimmunity is a branch of medicine linked to every single organ system via direct and indirect pathways, meeting in person to discuss autoimmunity during the 13^th international congress on autoimmunity (AUTO13) with participants from all over the world had a very good reason. The mechanisms involved in autoimmune diseases are of extreme importance and in fact critical in understanding the course of diseases as well as selecting proper therapies. COVID-19 has served as a great example of how autoimmunity is deeply involved in the disease and directly correlated to severity, morbidity, and mortality. For instance, initially the term cytokine storm dominated, then COVID-19 was addressed as the new member of the hyperferritinemic syndrome, and also the use of immunosuppressants in patients with COVID-19 throughout the pandemic, all shed light on the fundamental role of autoimmunity. Unsurprisingly, SARS-CoV-2 was called the “autoimmune virus” during AUTO13. Subsequently, the correlation between autoimmunity and COVID-19 vaccines and post-COVID, all were discussed from different autoimmune aspects during the congress. In addition, updates on the mechanisms of diseases, autoantibodies, novel diagnostics and therapies in regard to autoimmune diseases such as antiphospholipid syndrome, systemic lupus erythematosus, systemic sclerosis and others, were discussed in dedicated sessions. Due to the magnificence of the topics discussed, we aimed to bring in our article hereby, the pearls of AUTO13 in terms of updates, new aspects of autoimmunity, and interesting findings. While more than 500 abstract were presented, concluding all the topics was not in reach, hence major findings were summarized.

Efficacy of local prostaglandin analogues for vitiligo treatment: a systematic review and meta-analysis

BACKGROUND

Vitiligo is a common cutaneous depigmentation disorder. Although multiple treatment options are available, no single modality is satisfactory for all patients. Several studies have demonstrated that prostaglandin analogues can potentially treat cutaneous depigmentation, but the evidence is limited to their inconsistent study design.

RESEARCH DESIGN & METHODS

A systematic review was performed for studies published before 29 June 2021, in PubMed, Embase, Web of Science, or the Cochrane Library. The primary outcome of pooled analysis was the repigmentation efficacy of local prostaglandin analogues compared with other therapies for vitiligo.

RESULTS

Six randomized controlled trials (RCTs) and three non-RCTs were included in this systematic review, and seven studies among them were used for the meta-analysis. The pooled analysis demonstrated that local prostaglandin analogues could significantly increase repigmentation along with narrowband ultraviolet B phototherapy compared with phototherapy alone. Furthermore, the repigmentation efficacy of topical prostaglandin analogues was not significantly different from that of topical tacrolimus. In summary, local prostaglandin analogues either used alone or as add-on therapy could be safe and effective therapies for vitiligo.

Folic Acid Protects Melanocytes from Oxidative Stress via Activation of Nrf2 and Inhibition of HMGB1

Vitiligo is a cutaneous depigmentation disease due to loss of epidermal melanocytes. Accumulating evidence has indicated that oxidative stress plays a vital role in vitiligo via directly destructing melanocytes and triggering inflammatory response that ultimately undermines melanocytes. Folic acid (FA), an oxidized form of folate with high bioavailability, exhibits potent antioxidant properties and shows therapeutic potential in multiple oxidative stress-related diseases. However, whether FA safeguards melanocytes from oxidative damages remains unknown. In this study, we first found that FA relieved melanocytes from H₂O₂-induced abnormal growth and apoptosis. Furthermore, FA enhanced the activity of antioxidative enzymes and remarkably reduced intracellular ROS levels in melanocytes. Subsequently, FA effectively activated nuclear factor E2-related factor 2 (Nrf2) pathway, and Nrf2 knockdown blocked the protective effects of FA on H₂O₂-treated melanocytes. Additionally, FA inhibited the production of proinflammatory HMGB1 in melanocytes under oxidative stress. Taken together, our findings support the protective effects of FA on human melanocytes against oxidative injury via the activation of Nrf2 and the inhibition of HMGB1, thus indicating FA as a potential therapeutic agent for the treatment of vitiligo.