Integrating neuronal involvement into the immune and genetic paradigm of vitiligo

Neurological Mechanisms Exploration and Therapeutic Targets in Segmental Vitiligo Accompanied by White Hair

Vitiligo is the most common skin depigmentation disease, affecting 0.1%-2% of people in the world. 3.5%-20.5% of segmental patients account for the total number of vitiligo patients. It has been clinically observed that segmental vitiligo patients are more likely to generate white hair, which may be related to neuroendocrine factors. The color of human skin and hair is affected by the number and functional status of melanocytes. Vitiligo affects patients' physical and mental health due to the shame it causes from the white patches and hair. This article reviews the underlying mechanisms of segmental vitiligo with white hair based on skin and hair follicle melanocytes. The article attempts to propose possible targets for the treatment of this disease.

A comprehensive outline of the role of non-coding RNAs in vitiligo

Vitiligo is a common skin depigmentation condition caused by selective destruction of melanocytes. It is regarded as a polygenic disorder. In addition to protein-coding loci, non-coding regions of the genome contribute to the pathogenesis of vitiligo. A bulk of evidence highlights contribution of different classes of non-coding RNAs in this condition. Expression profile of different non-coding RNAs has been evaluated in the plasma, serum, blood cells and skin samples of patients with vitiligo. Notably, these transcripts not only partake the pathogenesis of vitiligo, but also are regarded as putative targets for prospective treatment strategies for this disorder. The current review focuses on depicting the role of miRNAs, long non-coding RNAs and circular RNAs in the etiology of vitiligo. Moreover, we discuss the shared functions of these transcripts in the pathogenesis of vitiligo and melanoma.

HSV-1 inhibits melanogenesis of PIG1 cells through downregulation of VN1R5/ERK pathway

Herpes simplex virus type 1 (HSV-1) is an ubiquitous pathogen that can infect humans through skin or mucous regions. This study was to explore the effects and underlying mechanism of HSV-1 as examined within the human epidermal melanocyte cell line, PIG1. Our results showed that following HSV-1 infection, PIG1 cells shrank and acquired a rounded shape, while the numbers and lengths of their dendrites decreased and melanogenesis was inhibited. Meanwhile, the HSV-1 receptors (nectin-1, herpes virus entry mediator, paired immunoglobulin-like type 2 receptor alpha) and phospho-extracellular signal-regulating kinase (p-ERK) were all substantially decreased, while vomeronasal type-1 receptor 5 (VN1R5) increased. Results of RNA interference and protein inhibitor assays revealed that knockdown of VN1R5 increased the expression of p-ERK and microphthalmia-associated transcription factor (MITF), while an inhibition of ERK decreased VN1R5 expression. Taken together, our study provides the first evidence that HSV-1 can infect human normal melanocytes and inhibit melanogenesis through VN1R5/ERK pathway.

Treatment Advances in Vitiligo: An Updated Review

INTRODUCTION

Vitiligo is a common disorder of depigmentation caused by the progressive destruction of melanocytes that affects the skin, hair, and mucous membranes, clinically presenting as depigmented macules and leukotrichia. This condition, affecting millions of people worldwide, has a significant psychosocial burden on patients' quality of life, particularly in relation to skin colour. The etiopathogenesis of this disorder is obscure, but multiple factors contribute to the loss of melanocytes in the skin, like oxidative stress, inflammation, genetics, and autoimmunity. The treatment of vitiligo has been challenging over the past years, but recent developments in understanding the etiopathogenesis of the disease have paved the way for the development of more effective and promising therapeutic treatment options.

OBJECTIVE

The aim of this review was to provide an overview of the underlying mechanisms and highlight the latest advances in the treatment of vitiligo.

METHODOLOGY

This review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Metanalyses) guidelines. A comprehensive search of the literature was carried out through the PubMed electronic database from inception to 31 December 2023 using the following search terms "vitiligo" AND "JAK inhibitors", "vitiligo" AND "prostaglandin", " vitiligo" AND " afamelanotide", "vitiligo" AND "antioxidants", "vitiligo" AND "vitamin D3", "vitiligo" AND "statins", "vitiligo" AND "TNF-alpha", "vitiligo" AND "interleukin", "vitiligo" AND "light therapy". Two independent reviewers screened titles, abstracts, and full texts to select papers dealing with vitiligo and its treatment.

CONCLUSION

The advent of treatment modalities like Janus kinase inhibitors, prostaglandin analogues, antioxidants, TNF-α inhibitors, targeted phototherapy, and excimer lasers has revolutionized the therapeutic possibilities, offering a ray of hope to the individuals suffering from this devastating condition.

Vitiligo: From Pathogenesis to Treatment

Recent advances in vitiligo have provided promising treatment options, particularly through understanding the immune-mediated mechanisms leading to depigmentation. The inflammatory components in both vitiligo (non-segmental) and segmental vitiligo have similarities. Both are believed to result from an immune-based destruction of melanocytes by anti-melanocyte-specific cytotoxic T cells. The JAK-STAT pathway is activated with IFN-γ as the crucial cytokine and Th1-associated chemokines such as CXCL9 and CXCL10 recruit immune cells towards vitiligo skin. Nonetheless, clear differences are also present, such as the localized nature of segmental vitiligo, likely due to somatic mosaicism and increased presence of poliosis. The differing prevalence of poliosis suggests that the follicular immune privilege, which is known to involve immune checkpoints, may be more important in vitiligo (non-segmental). Immunomodulatory therapies, especially those targeting the JAK-IFNγ pathway, are currently at the forefront, offering effective inhibition of melanocyte destruction by cytotoxic T cells. Although Janus Kinase (JAK) inhibitors demonstrate high repigmentation rates, optimal results can take several months to years. The influence of environmental UV exposure on repigmentation in patients receiving immunomodulating drugs remains largely underexplored. Nonetheless, the combined effect of phototherapy with JAK inhibitors is impressive and suggests a targeted immune-based treatment may still require additional stimulation of melanocytes for repigmentation. Identifying alternative melanocyte stimulants beyond UV light remains crucial for the future management of vitiligo.

Establishment of a promising vitiligo mouse model for pathogenesis and treatment studies

AIMS

Vitiligo is a chronic dermatological condition characterized by the progressive loss of melanocytes, for which traditional therapy has shown limited efficacy. This study aimed to establish a vitiligo model with easy operability, high repeatability, and stable depigmentation to provide a foundation for studying the pathogenesis and developing novel therapies for vitiligo.

METHODS

(1) Establishing vitiligo model: Firstly, deliver B16F10 cells to the back skin of C57BL/6 J via intradermal injection (day 0), and the CD4 depletion antibody was injected intraperitoneally on day 4 and 10. Secondly, the melanoma was surgically removed on day 12. Thirdly, CD8 antibody was administered intraperitoneally every fourth day till day 30. (2) Identification of vitiligo model: H&E staining, immunohistochemistry, and immunofluorescence were used to detect the melanocytes. The melanin was detected by transmission electron microscopy (TEM), Lillie ferrous sulfate staining and L-DOPA staining.

RESULTS

(1) The back skin and hair began to appear white on day 30. Melanin loss reached peak on day 60; (2) Hematoxylin and eosin (H&E) staining, immunohistochemistry and immunofluorescence results showed melanocytes were reduced. L-DOPA staining, Lillie ferrous sulfate staining and TEM results showed that melanin decreased in the epidermis.

CONCLUSION

We successfully establishment a vitiligo mouse model which can be more capable to simulate the pathogenesis of human vitiligo and provide an important basis for the study of pathogenesis and therapy of vitiligo.

Prevalence of Multiple Sclerosis in Vitiligo Patients and Their First-Degree Relatives: Two Diseases with Similarities in Pathogenesis and Treatment

INTRODUCTION

Vitiligo is a common pigmentation disorder manifested by white macules and patches. It is accompanied by some autoimmune and neurological diseases. Recently, it has been suggested that multiple sclerosis (MS) is more common in vitiligo patients and that they have a higher risk of developing MS during their lifetime.

OBJECTIVES

In this study, we aimed to determine the prevalence of MS in patients with vitiligo and their first-degree relatives and compare it with the prevalence in the population.

METHODS

In this cross-sectional study, data were consecutively collected from patients referred to Razi Hospital from March 2020 to December 2021.

RESULTS

Seven hundred and nine patients with vitiligo participated in this study, and 15 reported a history of MS (2.12%, 95% confidence interval [CI] 1.06%-3.17%). This rate was significantly higher than the prevalence of MS in the average population of Tehran (P < 0.001). Of the 2886 first-degree relatives of the patients, 10 had MS (0.35%, 95%CI 0.13&-0.56%), which was higher than the prevalence of MS, yet not statistically significant.

CONCLUSIONS

A significant association between vitiligo and MS was observed, which should be of clinical and therapeutic importance. However, the prevalence of MS in first-degree relatives of vitiligo patients was higher than the average rate, yet not statistically significant.

Patho-immunological mechanisms of vitiligo: the role of the innate and adaptive immunities and environmental stress factors

Epidermal melanocyte loss in vitiligo, triggered by stresses ranging from trauma to emotional stress, chemical exposure or metabolite imbalance, to the unknown, can stimulate oxidative stress in pigment cells, which secrete damage-associated molecular patterns that then initiate innate immune responses. Antigen presentation to melanocytes leads to stimulation of autoreactive T-cell responses, with further targeting of pigment cells. Studies show a pathogenic basis for cellular stress, innate immune responses and adaptive immunity in vitiligo. Improved understanding of the aetiological mechanisms in vitiligo has already resulted in successful use of the Jak inhibitors in vitiligo. In this review, we outline the current understanding of the pathological mechanisms in vitiligo and locate loci to which therapeutic attack might be directed.

Vitiligo-Associated Autoimmune Disorders: A Woman With Vitiligo and Incipient Hypothyroidism

Vitiligo is a skin condition that causes loss of pigmentation, resulting in hypopigmented and depigmented patches on the skin. Vitiligo has been associated with many autoimmune conditions. A 27-year-old female with a history of vitiligo had a clinical presentation and laboratory studies that were consistent with incipient hypothyroidism. The relationship between vitiligo, hypothyroidism, and other autoimmune conditions is discussed.