Vitiligo: an update on current pharmacotherapy and future directions

Vitamin D Receptor Gene Polymorphisms and Association with Vitiligo in Indonesian Population

Introduction

Vitiligo is an acquired depigmenting skin disorder due to the loss of melanocyte function in the epidermis and hair follicles. The pathogenesis of vitiligo is multifactorial, with genetics being a predisposing factor. Previous studies had varying results regarding whether or not polymorphisms of vitamin D receptor (VDR) gene are associated with the risk of vitiligo in specific populations. This study investigated the association between three frequently analyzed VDR gene polymorphisms (ApaI, BsmI, TaqI) and susceptibility to vitiligo in Indonesian population.

Methods

Thirty-four vitiligo patients and 34 age- and sex-matched healthy subjects aged ≥18 years old were recruited in the Dermatology and Venereology Outpatient Clinic of Dr. Hasan Sadikin General Hospital, Bandung, Indonesia. Genomic deoxyribonucleic acid (DNA) was extracted from the peripheral blood using a DNA isolation kit. VDR gene polymorphisms (ApaI, BsmI, and TaqI) were investigated using the polymerase chain reaction-restriction-fragment length polymorphism method. The differences of genotype distributions and allele frequencies were statistically compared between case and control groups using Chi-square test.

Results

VDR gene polymorphisms were identified in 68 participants, consisting of Aa (n = 14), aa (n = 20), Bb (n = 15), bb (n = 19), and TT (n = 34) genotypes in the case group. In the control group, Aa (n = 6), aa (n = 28), Bb (n = 17), bb (n = 17), and TT (n = 34) genotypes were identified. However, only subjects with ApaI Aa genotype polymorphism had a 3.267-fold increased risk of developing vitiligo.

Conclusion

This study showed that ApaI Aa genotype polymorphism of the VDR gene increases the risk of vitiligo in Indonesian population.

Vitiligo: An Updated Narrative Review

BACKGROUND

Vitiligo is a relatively common acquired pigmentation disorder that can cause significant psychological stress and stigmatism.

OBJECTIVE

This article aims to familiarize physicians with the clinical manifestations, evaluation, diagnosis, and management of vitiligo.

METHODS

A Pubmed search was conducted in Clinical Queries using the key term "vitiligo". The search included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews. The search was restricted to English language. The information retrieved from the above search was used in the compilation of the present article.

RESULTS

Approximately one quarter of patients with vitiligo have the onset before 10 years of age. Genetic, immunological, neurogenic and environmental factors may have a role to play in the pathogenesis. Vitiligo typically presents as acquired depigmented, well-demarcated macules/patches that appear milk- or chalk-white in color. Lesions tend to increase in number and enlarge centrifugally in size with time. Sites of predilection include the face, followed by the neck, lower limbs, trunk, and upper limbs. The clinical course is generally unpredictable. In children with fair skin, no active treatment is usually necessary other than the use of sunscreens and camouflage cosmetics. If treatment is preferred for cosmesis, topical corticosteroids, topical calcineurin inhibitors, and narrowband ultraviolet B phototherapy are the mainstays of treatment.

CONCLUSION

The therapeutic effect of all the treatment modalities varies considerably from individual to individual. As such, treatment must be individualized. In general, the best treatment response is seen in younger patients, recent disease onset, darker skin types, and head and neck lesions. Topical corticosteroids and calcineurin inhibitors are the treatment choice for those with localized disease. Topical calcineurin inhibitors are generally preferred for lesions on genitalia, intertriginous areas, face, and neck. Narrowband ultraviolet B phototherapy should be considered in patients who have widespread vitiligo or those with localized vitiligo associated with a significant impact on the quality of life who do not respond to treatment with topical corticosteroids and calcineurin inhibitors.

Emerging drugs for the treatment of vitiligo

Introduction: Vitiligo is a relatively common autoimmune depigmenting disorder of the skin. There has been a great advance in understanding the pathological basis, which has led to the development and utilization of various new molecules in treating vitiligo. This review aims at a comprehensively describing the treatments available and the emerging treatment aspects and the scope for future developments.Areas covered: This study comprehensively summarizes the current concepts in the pathogenesis of vitiligo with special focus on the cytokine and signaling pathways, which are the targets for newer drugs. JAK kinase signaling pathways and the cytokines involved are the focus of vitiligo treatment in current research, followed by antioxidant mechanisms and repigmenting mechanisms. Topical immunosuppressants may be an alternative to steroids in localized vitiligo. Newer repigmenting agents like basic fibroblast growth factors, afamelanotide have been included and a special emphasis is laid on the upcoming targeted immunotherapy.Expert opinion: The treatment of vitiligo needs to be multimodal with emphasis on targeting different limbs of the pathogenesis. Topical and oral JAK inhibitors are the most promising new class of drugs currently available for treating vitiligo and acts best in conjunction with NB-UVB.

Evidence of a possible therapeutic role of vitamin D in a cohort of adult Caucasian vitiligo patients

Reduced serum 25(OH)D levels have been largely reported in vitiligo, which is an autoimmune skin disorder characterized by the appearance of achromic macules. Since vitamin D can positively modulate immune function and stimulate melanogenesis in vitro, a possible role of sufficient vitamin D levels in promoting the stability of the disease and repigmentation process might be hypothesized in vitiligo. Hence, we conducted an observational study on medical records related to 101 vitiligo patients, in order to correlate baseline 25(OH)D levels with the baseline vitiligo activity and repigmentation of vitiligo macules on a 6-month follow-up. According to our results, at baseline we found that active vitiligo was significantly associated with 25(OH)D deficiency (≤20 ng/mL) (P = 0.036) or insufficiency (21-29 ng/mL) (P = 0.041), while stable disease was significantly associated with sufficient 25(OH)D levels (30-100 ng/mL) (P = 0.043). After 6 months, vitiligo patients with sufficient 25(OH)D levels (30-100 ng/mL) achieved a significantly higher degree of repigmentation. In conclusion, our study provides a novel evidence of a significant positive association of sufficient 25(OH)D levels with the stability of the disease and a satisfactory repigmentation process in Caucasian adult vitiligo patients and strengthen the need to assess vitamin D status in vitiligo. The correlation between sufficient vitamin D levels and a satisfactory course of the disease opens the way for future randomized controlled trials assessing a possible beneficial role of vitamin D supplementation on vitiligo.

Gynostemma pentaphyllum saponins induce melanogenesis and activate cAMP/PKA and Wnt/β-catenin signaling pathways

BACKGROUND

Melanogenesis is a physiological process of melanin production in response to UV exposure, which is modulated through multi-signaling pathways including cAMP/PKA, Wnt/β-catenin and MAPK signaling cascades.

HYPOTHESIS/PURPOSE

The present study aims to investigate the molecular mechanism of hyperpigmentation induced by Gynostemma pentaphyllum saponins.

STUDY DESIGN/METHODS

In this study, we investigated the melanogenic effects of triterpenoid saponins of Gynostemma pentaphyllum (GpS), a medicinal plant. Two mouse melanogenic cell lines B16 and B16F10 were employed for the current study.

RESULTS

The results showed that non-toxic doses of GpS markedly increased melanin formation in both B16 and B16F10 cells. Western blot analysis showed that GpS treatment significantly up-regulated the expression levels of the key melanogenic proteins, including tyrosinase (TYR), microphthalmia-associated transcription factor (MITF), TRP-1 and TRP-2 in a dose-dependent manner. The phospho-CREB, which is the downstream target of PKA is also elevated upon GpS treatment. We further observed that H89, a PKA inhibitor, attenuated the GpS induced tyrosinase activity, melanin content, the expression of phospho-CREB. In addition to the cAMP/PKA signaling pathway, GpS treatment also up-regulated the β-catenin of the Wnt signaling pathway which is involved in the transcriptional activation of MITF in melanogensis. We further demonstrated that treatment with GpS markedly enhance mRNA expression of MITF, along with the downstream target molecules, TYR, TRP-1 and TRP-2. Knock-down MITF with siMITF inhibited the expression of MITF mRNA by 63%, and the melanin content was reduced 70% in the siMITF-transfected cells compared to untransfected or scramble siRNA control cells.

CONCLUSION

These findings demonstrated strong melanogenic activities of GpS, and the MITF is essential for the melanogenesis stimulated by GpS.

An Innovative Therapeutic Protocol for Vitiligo: Experience with the Use of Fraxel Herbium Laser, Topical Latanoprost and Successive Irradiation with UVA - 1 Laser

Despite the continuous introduction of innovative therapies for vitiligo, today none of them provide constant and excellent results in term of repigmentation. The authors report their experience in treating a localised form of vitiligo with a new protocol consisting in the use of a Fraxel Herbium laser, and in the following application of topical Latanoprost solution and, one day after, in lesional irradiation with UVA1 laser.

Novel approaches to vitiligo treatment via modulation of mTOR and NF-κB pathways in human skin melanocytes

Vitiligo is a skin depigmentation disorder with an increasing prevalence. Among recognized mechanisms is the oxidative stress that affects melanocytes which are responsible for skin pigmentation. Studies have shown that high concentration of hydrogen peroxide, or H₂O₂, induces apoptotic activities. Few studies have been done with lower doses of H₂O₂. Using human skin melanocytes, we investigated the effect of moderate concentration of H₂O₂ on melanocyte dendrites. Confocal data show that H₂O₂ at 250 µM induces loss of dendrites, as indicated by cytoskeletal proteins. α-melanocyte stimulating hormone or α-MSH pretreatment protects against H₂O₂-induced loss of dendrites, while α-MSH alone enhances dendrites. PI3K/AKT inhibitor LY294002 and mTORC1 inhibitor Rapamycin inhibit α-MSH-induced dendrites. In this study, we also investigated the effect of TNFα on cultured human skin melanocytes, since TNFα plays important roles in vitiligo. Confocal data demonstrate that TNFα induces NFκB activation. Western blot analysis shows that TNFα induces IκB phosphorylation and degradation. Interestingly, α-MSH does not have any effect of TNFα-induced IκB degradation and NF-κB activation. α-MSH, however, activates mTORC1 pathway. TNFα induces p38 but not AMPKα activation. Collectively, our data suggest that modulation of mTOR and NF-κB pathways may be a novel approach for better clinical management of vitiligo.

Oxidative stress and immune system in vitiligo and thyroid diseases

Vitiligo is an acquired dermatological disease frequently associated with autoimmune thyroid disorders. Several theories have been proposed so far to unravel the complex vitiligo pathogenesis. Currently, the autocytotoxic and the autoimmune theories are the most accredited hypothesis, since they are sustained by several important clinical and experimental evidences. A growing body of evidences shows that autoimmunity and oxidative stress strictly interact to finally determine melanocyte loss. In this scenario, associated thyroid autoimmunity might play an active and important role in triggering and maintaining the depigmentation process of vitiligo.

Triple combination treatment with fractional CO2 laser plus topical betamethasone solution and narrowband ultraviolet B for refractory vitiligo: a prospective, randomized half-body, comparative study

Vitiligo on extremities and/or bony prominences is very resistant to treatment. Twenty-five patients with symmetrical and stable vitiligo on extremities and/or bony prominences were enrolled. The treatment side received fractional carbon dioxide laser followed by topical compound betamethasone solution and narrowband ultraviolet B phototherapy. The control side received laser treatment plus phototherapy. The result of treatment side showed that 44% patients achieved over 50% re-pigmentation and patient satisfaction score was 5.12 ± 3.23, higher than those of control (p < 0.05). Adverse events were slight and tolerable. The triple combination treatment could be used as an alternative modality for refractory vitiligo.

The effect of pseudocatalase/superoxide dismutase in the treatment of vitiligo: A pilot study

Objective:

Pseudocatalase/superoxide dismutase (PSD) is a topical gel considered having therapeutic effects in vitiligo. This study was designed to evaluate the efficacy of this combination in vitiligo.

Methods:

This was a pilot randomized, double-blind, placebo-controlled trial on 46 symmetrical vitiligo lesions of limbs in 23 patients referring to dermatology clinics, Isfahan, Iran in 2010. Patients were received this formula or placebo gels for the right and left lesions. Lesion area and degree of pigmentation were assessed at baseline, 2, 4, and 6 months.

Findings:

There were no significant changes in lesion area and perifollicular pigmentation in each group (P > 0.05).

Conclusion:

The results indicated no significant therapeutic effect for PSD in vitiligo.

Role of oxidative stress in the pathogenesis of vitiligo with special emphasis on the antioxidant action of narrowband ultraviolet B phototherapy

Objectives

To evaluate the role of oxidative stress in the pathogenesis of vitiligo and the effect of narrowband (NB) ultraviolet (UV) B phototherapy on oxidative stress markers.

Methods

Patients with vitiligo and healthy control subjects were included in the study. Patients in the vitiligo group were treated with an NB-UVB regimen (3 × weekly for 6 months). Erythrocyte superoxide dismutase activity (SOD), erythrocyte malonyldialdehyde (MDA) and erythrocyte glutathione peroxidase activity (GSH-Px) levels were assessed in all participants at baseline, and after NB-UVB phototherapy in patients with vitiligo.

Results

A total of 24 patients with vitiligo and 27 control subjects were included in the study. Before treatment, erythrocyte MDA levels were significantly higher, and SOD and GSH-Px levels were significantly lower, in patients with vitiligo compared with controls. NB-UVB phototherapy was associated with a significant reduction in MDA levels and a significant increase in GSH-Px levels, compared with baseline, in patients with vitiligo.

Conclusion

NB-UVB phototherapy may relieve oxidative stress in patients with vitiligo by reversing the oxidant–antioxidant imbalance that is considered to play a role in the pathogenesis of this disease.

Mutant HSP70 reverses autoimmune depigmentation in vitiligo

Vitiligo is an autoimmune disease characterized by destruction of melanocytes, leaving 0.5% of the population with progressive depigmentation. Current treatments offer limited efficacy. We report that modified inducible heat shock protein 70 (HSP70i) prevents T cell-mediated depigmentation. HSP70i is the molecular link between stress and the resultant immune response. We previously showed that HSP70i induces an inflammatory dendritic cell (DC) phenotype and is necessary for depigmentation in vitiligo mouse models. Here, we observed a similar DC inflammatory phenotype in vitiligo patients. In a mouse model of depigmentation, DNA vaccination with a melanocyte antigen and the carboxyl terminus of HSP70i was sufficient to drive autoimmunity. Mutational analysis of the HSP70i substrate-binding domain established the peptide QPGVLIQVYEG as invaluable for DC activation, and mutant HSP70i could not induce depigmentation. Moreover, mutant HSP70iQ435A bound human DCs and reduced their activation, as well as induced a shift from inflammatory to tolerogenic DCs in mice. HSP70iQ435A-encoding DNA applied months before spontaneous depigmentation prevented vitiligo in mice expressing a transgenic, melanocyte-reactive T cell receptor. Furthermore, use of HSP70iQ435A therapeutically in a different, rapidly depigmenting model after loss of differentiated melanocytes resulted in 76% recovery of pigmentation. Treatment also prevented relevant T cells from populating mouse skin. In addition, ex vivo treatment of human skin averted the disease-related shift from quiescent to effector T cell phenotype. Thus, HSP70iQ435A DNA delivery may offer potent treatment opportunities for vitiligo.

Narrow band-ultraviolet B versus clobetasol propionate foam in the treatment of vitiligo: a retrospective study

INTRODUCTION

Several therapeutic options are available for the treatment of vitiligo; among these phototherapy and topical steroids are the most widely documented. A topical formulation of 0.05% clobetasol propionate foam (CPF) has been introduced in the market, but no data are available about the efficacy and tolerability of this new formulation in the treatment of vitiligo. The aim of this study was to investigate the efficacy and tolerability of CPF in the treatment of vitiligo, in comparison with narrowband-ultraviolet B (NB-UVB) phototherapy.

METHODS

The medical records of the first 60 vitiligo patients treated with NB-UVB phototherapy or with CPF were selected. Response to the treatment was determined for each anatomic site (neck, upper and lower limbs, trunk, hands/wrists, feet/ankles). Based on the area of repigmentation, treatment outcome was calculated according to a scale ranging from 0 (absent) to 4 (excellent). The incidence of adverse effects was also noted as a secondary endpoint. Significance level was set at P = 0.05.

RESULTS

For each anatomic site, statistical analyses demonstrated that the efficacy of CPF was significantly higher compared to NB-UVB. Side effects occurred in 4 patients (13.33%) in the CPF group compared to none in the NB-UVB group.

DISCUSSION

Clobetasol propionate has been used in vitiligo in different vehicles, but never in foam. The data showed that CPF is effective and seems to be superior to NB-UVB phototherapy, with furthermore a good safety profile.

CONCLUSION

This new foam formulation of clobetasol propionate may expand the options currently available for vitiligo therapy; however, further investigations are needed to confirm our preliminary observations.