Cellular and Molecular Mechanisms Involved in the Action of Vitamin D Analogs Targeting Vitiligo Depigmentation

In vitro and in vivo anti-pigmentation effects of 2-mercaptobenzimidazoles as nanomolar tyrosinase inhibitors on mammalian cells and zebrafish embryos: Preparation of pigment-free zebrafish embryos

Recently, 10 2-mercaptobenzo[d]imidazole (2-MBI) compounds (1-10) were synthesized. Although all 2-MBI compounds are tyrosinase inhibitors that inhibit mushroom tyrosinase at extremely low concentrations (IC50 values: 20-740 nM) and effectively inhibit the browning of apples, to our knowledge, no studies have determined whether 2-MBI compounds inhibit mammalian tyrosinase. Mammalian tyrosinase is different from mushroom tyrosinase in its distribution within the cell and has structural characteristics that are different from mushroom tyrosinase in amino acid sequence and in the presence of a quaternary structure. Thus, the effect of the 10 2-MBI compounds on mammalian tyrosinase activity was investigated in B16F10 cells. Six compounds (1-6) exhibited stronger intracellular tyrosinase inhibition than that of kojic acid and phenylthiourea (PTU), which are known to be the most potent tyrosinase inhibitors; their strong tyrosinase inhibitory activity robustly inhibited intracellular melanin production in B16F10 cells. None of the tested 2-MBI compounds exhibited appreciable cytotoxicity in HaCaT and B16F10 cells. To confirm the anti-melanogenic efficacy of the 2-MBI compounds in vivo, a zebrafish embryo model was used. At concentrations 100 times lower than kojic acid, most 2-MBI compounds demonstrated much stronger depigmentation efficacy than that of kojic acid, and three 2-MBI compounds (2-4) showed depigmentation activity similar to or more potent than that of PTU, resulting in nearly pigment-free zebrafish embryos. These results suggest that 2-MBI compounds may be potential therapeutic agents for hyperpigmentation-related disorders.

Vitamin D and Interleukin-17: Are These Serum Biomarkers Useful in Non-Segmental Vitiligo? A Case Control Study from Central India

Non-segmental vitiligo (NSV) is an autoimmune disorder due to the destruction of melanocytes, where cytokines like interleukin 17 (IL-17) and biomolecules like vitamin D play a theoretical role in pathogenesis. Previous studies in this regard yielded inconsistent results. This study aimed to compare the serum levels of IL-17 and vitamin D between NSV patients and healthy controls and to know the association of these biomarkers with disease activity and extent. This was a case-control study including adult patients with NSV and age and gender-matched healthy controls. Cases and controls with conditions likely to alter the serum levels of IL-17 and vitamin D were excluded. Serum levels of IL-17 were estimated by ELISA and vitamin D levels by chemiluminescence assay. 42 adult patients of NSV and 42 age and sex-matched healthy controls were recruited over a period of eighteen months. The mean value of serum vitamin D levels in the control group was 19.053 ± 5.340 ng/ml, whereas in the case group, it was 17.336 ± 6.931 ng/ml (P > 0.05). The mean value of serum IL-17 levels in the control group was 199.824 ± 51.244 pg/ml and 213.566 ± 69.018 pg/ml in the case group (P > 0.05). These molecules did not show any association with the disease activity and extent. In contrast to the previous studies, we could not establish the role of IL-17 in the pathogenesis of vitiligo. Furthermore, we could not find any association between vitamin D and vitiligo in our study, even though there is an inconsistent association between the two in the available literature.

Using a Topical Formulation of Vitamin D for the Treatment of Vitiligo: A Systematic Review

Vitamin D is one significant prohormone substance in human organ systems. It is a steroidal hormone produced in the skin upon exposure to UVB rays. This paper presents a systematic review of the utilization of topical vitamin D, specifically cholecalciferol, calcipotriol, and tacalcitol, in the treatment of vitiligo. It considers the role of vitamin D in stimulating the synthesis of melanin and melanogenesis, which can help with the process of repigmentation. The inclusion of calcipotriol or tacalcitol in Narrowband Ultraviolet Phototherapy (NB-UVB) has shown the potential to enhance therapeutic outcomes for vitiligo. However, their effectiveness in combination with Psoralens Long Wave Ultraviolet Radiation (PUVA) and Monochromatic Excimer Light (MEL) treatment for vitiligo is limited. In contrast, combining topical corticosteroids with vitamin D analogues has demonstrated superior efficacy in treating vitiligo compared to using vitamin D analogues alone, while also providing the added benefit of reducing corticosteroid-related adverse effects. In addition, treating stable vitiligo with topical cholecalciferol and microneedling has shown success. Future studies are needed to ascertain an efficient method of administering vitamin D topically as an anti-vitiligo agent.

Post-Inflammatory Hypopigmentation: Review of the Etiology, Clinical Manifestations, and Treatment Options

Post-inflammatory hypopigmentation is a common acquired pigmentary disorder that is more prominent in skin of color, leading to great cosmetic and psychosocial implications. Often, a diagnosis with a pigmentary disorder can negatively impact an individual's health-related quality of life and may result in stigma. Although most cases of post-inflammatory hypopigmentation resolve spontaneously over time, a systematic diagnostic approach can help with identifying the underlying etiology and informing treatment strategies. It can be due to cutaneous inflammation, sequelae of inflammatory or infectious dermatoses, or dermatologic procedures. Therefore, a thorough understanding of the epidemiology, patient history, physical exam findings, and clinical features of post-inflammatory hypopigmentation phenomenon can explain the primary cause to providers and allow for patient education. It is also important to understand the various therapeutic approaches available and the efficacy of these options, which will inform providers to choose the appropriate therapy for patients. Although algorithms exist for classifying acquired disorders of hypopigmentation, there are no established algorithms for the diagnosis and treatment of post-inflammatory hypopigmentation, which warrants further exploration and discourse.

Plant-Derived Compounds as Promising Therapeutics for Vitiligo

Vitiligo is the most common depigmenting disorder characterized by white patches in the skin. The pathogenetic origin of vitiligo revolves around autoimmune destruction of melanocytes in which, for instance, oxidative stress is responsible for melanocyte molecular, organelle dysfunction and melanocyte specific antigen exposure as well as melanocyte cell death and thus serves as an important contributor for vitiligo progression. In recent years, natural products have shown a wide range of pharmacological bioactivities against many skin diseases, and this review focuses on the effects and mechanisms of natural compounds against vitiligo models. It is showed that some natural compounds such as flavonoids, phenols, glycosides and coumarins have a protective role in melanocytes and thereby arrest the depigmentation, and, additionally, Nrf2/HO-1, MAPK, JAK/STAT, cAMP/PKA, and Wnt/β-catenin signaling pathways were reported to be implicated in these protective effects. This review discusses the great potential of plant derived natural products as anti-vitiligo agents, as well as the future directions to explore.

The addition of topical calcipotriol to phototherapy enhance the efficacy of treatment in patients with vitiligo: A systematic review and meta-analysis

BACKGROUND

Treatment of vitiligo has several challenges. Phototherapy and topical calcipotriol have been reported to be effective in combination with other therapies, but there is no consensus on the combination use.

OBJECTIVE

To perform a systematic review and meta-analysis that elucidates the efficacy of the combination of phototherapy and topical calcipotriol.

METHODS

This systematic review was performed by searching PubMed, EMBASE, Web of Science, Cochrane Library databases, Chinese National Knowledge Infrastructure (CNKI), WanFang and VIP databases for relevant publications till February 28, 2021. Relative risk (RR) and its 95% confidence interval (CI) were used to evaluate the data. Bias assessment, heterogeneity and sensitivity analysis were conducted in this meta-analysis.

RESULTS

After screening, nine studies with 700 participants were included. The meta-analysis indicated that the combination of phototherapy and topical calcipotriol showed significantly higher effective rate (RR 1.11, 95% CI 1.02-1.22; p < 0.05) and apparent effective rate (RR 1.35, 95% CI 1.15-1.59; p < 0.01) than phototherapy monotherapy in the treatment of vitiligo. In addition, the side effects were minor, transient and tolerable.

CONCLUSIONS

This meta-analysis provides evidence supporting phototherapy combined with topical calcipotriol as a valuable treatment modality for patients with vitiligo, which has better efficacy than monotherapy.

Vitiligo: Translational research and effective therapeutic strategies

This is an exciting phase of vitiligo research with the current understanding of vitiligo pathogenesis and its translation to successful treatment. The pathogenetic origin of vitiligo revolves around autoimmunity with supporting role from many other factors like oxidative stress, inherent melanocyte defects, or defective keratinocytes and fibroblasts. Vitiligo can be classified into segmental or non-segmental depending upon the clinical presentation, or it can be classified as progressing or stable based on the activity of the disease. Vitiligo treatments need to be stratified depending upon which type of vitiligo we are treating and at which phase the vitiligo patient presents to us. There are two different aims of treatment of vitiligo. The first involves rescuing the melanocytes from the damage to arrest the depigmentation. The second strategy focuses on replenishing the melanocytes so that successful repigmentation is achieved. It is also important to maintain the disease in a stable phase or prevent relapse. As stability in non-segmental vitiligo is a dynamic process, maintenance of the stability of repigmentation is also an important consideration in the management of vitiligo. In this review, we shall briefly discuss the current options and future insight into the management of vitiligo.

Nuclear factor erythroid 2-related factor 2 (Nrf2) as a potential therapeutic target for vitiligo

Vitiligo is an autoimmune disease of the skin which causes loss of melanocytes from the epidermis. Recently, it is demonstrated that oxidative stress (OS) plays a significant role in the immuno-pathogenesis of vitiligo. A major mechanism in the cellular defense against OS is activation of the nuclear factor erythroid2-related factor (Nrf2)-Kelch-like ECH-associated protein 1(Keap1)-antioxidant responsive element (ARE) signaling pathway. Recently it has been shown that vitiligo melanocytes have impaired Nrf2-ARE signaling. A number of drugs including those known as Nrf2 activators and those known to possess effects to activate Nrf2, have been used in treating vitiligo with certain therapeutic effects. Also, studies have shown that a number of compounds can protect melanocytes against OS via activating Nrf2. These compounds may be considered as candidates for developing new drugs for vitiligo in the future. Nrf2 can be considered as a potential therapeutic target for vitiligo.

"Ecological risk assessments and eco-toxicity analyses using chemical, biological, physiological responses, DNA damages and gene-level biomarkers in Zebrafish (Danio rerio) in an urban stream"

We conducted the ecological risk assessment in an urban stream by using multiple-level approaches ranging from community level, chemical analyses in water and sediments, physiological assays of DNA biomarkers, embryonic development tests, and gene-level marker analyses of cyp1a, c-Fos, CRH, transgenic fli1:GFP and HuC:eGFP in zebrafish (Danio rerio). In water, the chemical perturbations based on nutrients (N,P), organic matter, ionic contents and metals identified in downstream zone. Analogous corroborations verified in sediment samples having hazardous metals (Zn, Pb, Cu, Ni, As, Cd). The chemical contaminations reflected significant damages in fish DNA, based on tDNA, tail length (TL), and tail extent moment (TEM). Zebrafish embryonic development experiments significantly enlightened the chemical contaminants in downstream compared to those in control and reference conditions. Hatching and survival rates rigorously declined in downstream region. Embryonic development delayed and followed by death in the downstream substantiated by the above-mentioned findings. Similar were the findings on heart rate and pigmentation largely affected in the contaminated zone. Pollutants in urban stream reflected significantly at the gene level, and were corroborated through experiments using transgenic zebrafish strains that were influenced by pollutants during the process of occurrence. In conclusion, these studies illuminate the community to gene-level ecological health assessment that could be useful for ecological risk assessments of urban streams and rivers. Further, the gene-level biomarkers and transgenic zebrafish experiments combination propose the procedures could be effectively used as sensitive and efficient biomarkers of ecological health and risk assessment in urban streams from community to gene-level assessments.

Therapeutic effects of iNOS inhibition against vitiligo in an animal model

Nitric oxide (NO) is involved in several biological processes, but its role in human melanogenesis and vitiligo need further studies. Previous studies revealed that exposure to UVA and UVB were capable of the inducing nitric oxide production in keratinocytes and melanocytes through the activation of constitutive nitric oxide synthase, whereas inducible nitric oxide synthase overexpression has been reported to play an important role in hyperpigmentary disorders. The aim of this study was to evaluate iNOS inhibitor aminoguanidine (AG) as a therapeutic agent in our mouse model of vitiligo. In this study, male C57BL/6J Ler-vit/vit mice were purchased to evaluate the effect of iNOS inhibitor (aminoguanidine) (50 and 100 mg/kg) and L-arginine (100 mg/kg) in a mouse model of vitiligo induced by monobenzone 40%. Moreover, we used phototherapy device to treat the mice with NBUVB as a gold standard.The findings revealed that monobenzone was capable of inducing depigmentation after 6 weeks. However, aminoguanidine in combination with monobenzone was decrease the effect of monobenzone, while L-arginine play a key role in promoting the effect of monobenzone (P<0.001). Based on the phototherapy, the efficacy of phototherapy significantly increased by adding L-arginine (P<0.05). Taken together, we suggest that iNOS inhibitor can be a novel treatment for the prevention and treatment of vitiligo by combination of NBUVB therapy, furthermore; NO agents like L-arginine could also increase the effectiveness of phototherapy. Taken together, this pilot study showed significant repigmentation of vitiligous lesions treated with iNOS inhibitor plus NBUVB therapy, where other aspect including expression of an inducible iNOS, NO and TNF levels remained to be evaluated in mice model.

Vitamin D protects human melanocytes against oxidative damage by activation of Wnt/β-catenin signaling

Vitamin D analogs have been widely utilized for the treatment of vitiligo, but the molecular mechanism underlying their pharmacological effects (especially their antioxidant properties) has not yet been investigated. We evaluated the relationship between serum vitamin D level and oxidative damage severity in vitiligo patients, and investigated the molecular mechanism of vitamin D in protecting melanocytes against oxidative stress. Serum levels of 25-hydroxyvitamin D and malondialdehyde (MDA) were first measured in patients. A variety of in vitro experiments such as intracellular reactive oxygen species (ROS), cellular viability, migration, and apoptotic assays were then performed to detect the effects of vitamin D or β-catenin silencing on H₂O₂-treated melanocytes. Expression of Wnt/β-catenin, Nrf2, apoptotic, and MITF pathways was finally examined using quantitative real-time PCR and western blot. In this study, we initially found that vitamin D insufficiency was closely associated with the severity of oxidative stress in vitiligo patients. Using ex vivo cell models, we further showed that vitamin D positively modulated β-catenin signaling at both translational and posttranslational levels in melanocytes under oxidative stress. Like WNT agonists, vitamin D significantly inhibited ROS accumulation and cell apoptosis in H₂O₂-treated melanocytes and promoted their proliferative and migratory activity, while the protective effects of vitamin D against oxidative stress were abolished by β-catenin silencing in melanocytes. Furthermore, β-catenin deficiency also blocked the activation of Nrf2 and MITF as well as the inhibition of apoptosis induced by vitamin D. Taken together, vitamin D insufficiency was associated with severity of oxidative stress in vitiligo patients. Our work also provides new insights into the mechanism of vitamin D against vitiligo, in which vitamin D protects melanocytes against oxidative stress by activating Wnt/β-catenin signaling.

Vitamin D receptor gene polymorphism, serum 25-hydroxyvitamin D levels, and risk of vitiligo: A meta-analysis

OBJECTIVES

To explore the relationship among the vitamin D receptor (VDR) gene polymorphisms, serum 25-hydroxyvitamin D levels, and vitiligo.

METHODS

Databases including PubMed, Cochrane Library, Ovid, Web of Science, CNKI, SinoMed, and Wanfang Data were systematically searched. The association was assessed using odds ratios (ORs), standard mean difference (SMD), and 95% confidence intervals (CIs). The statistical tests were performed using Review Manager 5.3.3.

RESULTS

We identified a total of 17 studies. The relationship between VDR gene polymorphisms (BsmI, ApaI, TaqI, and FokI), serum 25 (OH)D levels, and incidence of vitiligo was investigated. The results of this meta-analysis showed that the dominant genetic model (CC+AC vs AA, P = .007, OR = 1.41, 95% CI = 1.10-1.80), recessive genetic model (CC vs AC+AA, P = .01, OR = 4.10, 95% CI = 1.36-12.35), and allelic contrast model (C vs A, P = .005, OR = 1.87, 95% CI = 1.21-2.90) of VDR Apal locus increased the risk of vitiligo, and BsmI, TaqI, and FokI loci and the risk of vitiligo have no obvious correlation. Serum 25 (OH)D deficiency was positively associated with the incidence of vitiligo (P < .0001, SMD = -0.94, 95% CI = -1.39, -0.48).

CONCLUSION

This meta-analysis revealed that VDR Apal polymorphism increased the susceptibility risk of vitiligo, and there is a positive correlation between serum 25 (OH)D deficiency and the incidence of vitiligo.

Evaluation of the correlation between serum levels of vitamin D and vitamin D receptor gene polymorphisms in an Egyptian population

BACKGROUND

Vitiligo is an autoimmune depigmentation disorder. Polymorphisms in the vitamin D receptor (VDR) have been found to be associated with vitiligo.

OBJECTIVES

To evaluate the potential association between VDR gene polymorphisms (ApaI, TaqI, and FokI) and vitiligo susceptibility, and to detect if there is correlation between serum 25-hydroxyvitamin D [25(OH)D] levels and vitiligo and between VDR gene polymorphisms and 25(OH)D levels in vitiligo.

MATERIALS AND METHODS

Seventy-five patients with vitiligo and 75 age and sex-matched controls were subjected to detailed history taking and dermatological examination to determine the extent and clinical type of vitiligo. A blood sample (5 ml) was retrieved to investigate VDR gene polymorphisms and serum 25(OH)D level.

RESULTS

Our results showed that the serum level of vitamin D is statistically significantly lower in patients than controls. The frequency of the ApaI variant a allele, the variant genotype (aa), and the variant genotype (tt) were significantly higher among the vitiligo cases than among controls. Our study also showed that the serum 25(OH)D levels were not significantly different among the different ApaI, TaqI, and FokI genotypes.

CONCLUSION

The present study showed that serum level of 25(OH)D is statistically significantly lower in patients than controls, so screening for vitamin D deficiency seems of value in patients with vitiligo for the possibility of vitamin D supplementation. We also report that VDR gene polymorphisms may be a risk for the development of vitiligo in an Egyptian population.

Phototherapy: The vitiligo management pillar

Phototherapy has been the mainstay of vitiligo therapy for several decades. A variety of wavelengths and modalities are available, but narrowband ultraviolet B remains the safest and most commonly used treatment. Acting on multiple steps in vitiligo pathogenesis, narrowband ultraviolet B is one of the few therapies that can effectively induce stabilization and stimulate repigmentation. Achievement of optimal results involves using a combination of appropriate treatment protocols, careful patient selection, and patient education to set expectations. Individual patient characteristics, including disease activity, vitiligo phenotype, lesion location, and skin phototype, should all be considered, along with combination therapies.

Phototherapy and vitamin D

The skin is the site for the photosynthesis of vitamin D and is a target tissue for the active metabolite of vitamin D. An increasing body of evidence indicates that vitamin D produced during phototherapy may be responsible for the positive effects observed during treatment of some skin diseases. Topical or oral application of vitamin D derivatives are used alone or with phototherapy. This paper reviews what is known about the use of phototherapy to enhance vitamin D levels, the use of vitamin D analogues with phototherapy, the efficacy of combination therapies, and controversies regarding some of the outcomes. Vitamin D can play a beneficial role in treating psoriasis, even though the exact role of vitamin D in the pathogenesis and severity of psoriasis remains unclear. The role of vitamin D in vitiligo, atopic dermatitis, polymorphic light eruption, and mycosis fungoides must be further investigated.

[Treatment of vitiligo]

The range of treatment options for vitiligo has significantly expanded in the last 10 years and we can offer our patients more effective treatment strategies supported by European guidelines and consensus findings. Topical and UV therapy are-often in combination-the main components of vitiligo treatment. The main outcome parameters include extent and maintenance of gained repigmentation, cessation of spreading, avoidance of side effects and the influence of the treatment on the quality of life. The efficacy of the currently available treatments is often limited. New options include antioxidative or melanocyte-stimulating adjuvant therapies in combination with UV or laser light as well as a topical maintenance treatment to reduce the risk of recurrences. In many cases, psychological support is indicated.

Vitamin D Receptor Expression in Vitiligo

Background:

Vitiligo is a progressive depigmenting disorder characterized by loss of functional melanocytes from the epidermis. The etiopathogenesis of vitiligo is still unclear. Vitamin D has stimulatory effects on melanocytes and acts through its nuclear Vitamin D receptor (VDR) on target cells.

Aims and Objectives:

The purpose of this study was to declare the role of Vitamin D in the pathogenesis of vitiligo.

Materials and Methods:

This case-control study included 30 vitiligo patients and 30 age, gender-matched healthy controls. Blood samples were withdrawn from the study subjects, and the serum 25(OH) D level was determined by an enzyme-linked immunosorbent assay technique. Serum 25(OH) D levels were divided into: Normal or sufficient (≥30 ng/ml), insufficient (< 30-> 20ng/ml), and deficient (≤20 ng/ml) levels. Skin biopsies were obtained from the depigmented lesions and clinically normal skin of vitiligo patients and from the controls, and VDR gene expression was determined using real-time polymerase chain reaction.

Results:

Only 10 patients with vitiligo (33.3%) had sufficient serum 25(OH) D levels (≥30 ng/ml), 12 patients (40%) had insufficient levels, and 8 patients (26.7%) had deficient levels. On the other hand, most of the controls (96.7%) had sufficient levels. The mean serum 25(OH) D level in patients was significantly decreased compared to controls (P < 0.001). The VDR-mRNA expression was also significantly decreased in lesional and nonlesional skin of patients compared to controls (P < 0.001, P < 0.001, respectively).

Conclusion:

Vitamin D deficiency influences the extent of vitiligo and could contribute to the pathogenesis of vitiligo through its immunomodulatory role and its role in melanogenesis.

Vitamin D and the skin: Focus on a complex relationship: A review

The "sunshine" vitamin is a hot topic that attracted ample attention over the past decades, specially that a considerable proportion of the worldwide population are deficient in this essential nutrient. Vitamin D was primarily acknowledged for its importance in bone formation, however; increasing evidence point to its interference with the proper function of nearly every tissue in our bodies including brain, heart, muscles, immune system and skin. Thereby its deficiency has been incriminated in a long panel of diseases including cancers, autoimmune diseases, cardiovascular and neurological disorders. Its involvement in the pathogenesis of different dermatological diseases is no exception and has been the subject of much research over the recent years. In the current review, we will throw light on this highly disputed vitamin that is creating a significant concern from a dermatological perspective. Furthermore, the consequences of its deficiency on the skin will be in focus.

The Relationship Between the Serum Level of Vitamin D and Vitiligo: A Controlled Study on 300 Subjects

BACKGROUND

Low vitamin D levels have been associated with several autoimmune diseases. Vitiligo could be associated with low vitamin D levels.

OBJECTIVE

To determine the level of serum vitamin D in vitiligo patients compared to controls and reveal the possible association of vitamin levels with the pathogenesis of vitiligo.

PATIENTS AND METHODS

A case-controlled study was conducted. After excluding factors that may affect serum vitamin D levels, blood samples were taken from vitiligo patients and controls. The association between vitamin D levels and various vitiligo subgroups (duration of vitiligo, site of onset, age, etc) was measured and correlated.

RESULTS

A total of 150 vitiligo patients, 90 (60%) males with a mean age of 30.6 ± 11.4 years, were recruited. The study also had 150 age- and gender-matched vitiligo-free control subjects. There was no significant difference in median serum vitamin D levels between the cases and the controls (P = .25). The serum levels of vitamin D of the vitiligo patients were found to be lower in males (P = .01), the younger age group (P = .01), and patients not treated with ultraviolet (UV) treatment (P = .01).

CONCLUSION

There is no difference between the vitamin D levels of the vitiligo patients and the control subjects. However, deficiency of 25(OH)D levels within the vitiligo subgroups may be linked to younger age, male gender, short duration of vitiligo, and non-use of phototherapy.

Comorbidities associated with vitiligo: a ten-year retrospective study

BACKGROUND

Vitiligo is a common disorder of depigmentation that has been associated with other autoimmune diseases. No recent large-scale data exist on the rates of comorbidities associated with vitiligo from the United States population.

OBJECTIVES

To identify the prevalence of comorbidities as well as associated laboratory abnormalities in vitiligo patients.

METHODS

All medical records dating from January 1, 2000 to June 21, 2011 within the Research Patient Data Repository were evaluated retrospectively using a novel artificial intelligence-based computer program. A total of 3,280 patients carrying the diagnosis of vitiligo were identified using ICD-9 code 709.01. We randomly selected 300 patients and validated the diagnosis by manually reviewing their medical records. These results were used to create a model that was then applied to the larger set yielding 2,441 true vitiligo patients. 1,657 (68%) were diagnosed by dermatologists and 784 (32%) by non-dermatologists. We identified the prevalence of other comorbid autoimmune conditions by searching problem lists of vitiligo patients and collected laboratory data from the first available data point in the system for each patient.

RESULTS

Women were more frequently represented (57.6%) than men (42.4%). The majority of vitiligo patients were White/Caucasian (56.9%), followed by Hispanic/Latino (19.4%). 565 (23%) had one of the following comorbidities: 287 thyroid-related, 186 psoriasis, 72 rheumatoid arthritis, 59 alopecia areata, 55 inflammatory bowel disease, 53 systemic lupus and 20 type I diabetes mellitus. 41% had elevated anti-nuclear antibody levels. Almost half of the patients tested had elevated thyroid peroxidase antibodies. Over 50% of the patients tested had low or insufficient levels of 25-OH vitamin D.

CONCLUSION

We found a high prevalence of comorbidities among individuals with vitiligo presenting to teaching hospitals in Boston, Mass. Comorbid autoimmune conditions were seen in 23% of vitiligo patients, thyroid disorders and psoriasis being the most common. Screening for these conditions, especially thyroid disorders, should be considered in vitiligo patients.

Vitamin D status and concomitant autoimmunity in celiac disease

GOALS

To determine whether patients with celiac disease (CD) and low vitamin D levels also have a higher prevalence of other autoimmune diseases (AD) as compared with patients with normal vitamin D levels.

BACKGROUND

Patients with CD carry a higher risk of other autoimmune disorders. Because of its immunoregulatory properties, vitamin D deficiency has been proposed in the pathogenesis of a variety of AD. Whether low vitamin D levels in patients with CD can predict concomitant AD is unknown.

STUDY

A retrospective cross-sectional study of 530 adult patients with CD and a 25-hydroxyvitamin D level on record at Columbia University Medical Center.

RESULTS

One hundred thirty-three patients (25%) had vitamin D deficiency. The prevalence of AD was similar among those with normal vitamin D levels (11%), insufficiency (9%), and deficiency (12%, P=0.66). On multivariate analysis, adjusting for age of CD diagnosis and sex, vitamin D deficiency was not associated with AD (odds ratio, 1.35; 95% confidence interval, 0.62-2.95). The risk of psoriasis was higher in patients with vitamin D deficiency (7% vs. 3%, P=0.04). Vitamin D deficiency was more common in those who presented with anemia (39%) than in those who did not (23% P=0.002).

CONCLUSIONS

Vitamin D deficiency in CD is common but does not predict AD. The risk of psoriasis is increased in vitamin D-deficient CD patients. Assessment of vitamin D seems to be a high-yield practice, especially in those CD patients who present with anemia.

The regulation of epidermal melanogenesis via cAMP and/or PKC signaling pathways: insights for the development of hypopigmenting agents

Abnormal pigmentation, particularly hyperpigmentation, is major issue of concern for people with colored skin. Several hypopigmenting agents, which exert their action by inhibiting tyrosinase activity and/or transcription, have been used for treatment. However, results have been discouraging. To manage abnormal pigmentation properly, the mechanisms of melanogenesis should be understood. Endogenous and exogenous factors affect melanogenesis via intracellular machineries. cAMP and PKC are critical factors of important transduction pathways and cross-talk between them could amplify the melanogenic effect. Here, factors involved in melanogenesis regulation via cAMP and/or PKC pathways are reviewed with their action mechanisms.

Vitiligo road map

Vitiligo is a depigmenting disorder stemming from melanocyte loss or dysfunction. It has a complex, multifaceted etiology. We constructed a "vitiligo road map," consisting of basic science, clinical, and treatment components, in order to better portray our current understanding of vitiligo pathogenesis and reflect upon novel biomarkers and therapeutic targets for future research. The melanocyte map elaborates on the molecular processes and intracellular signaling pathways initiated by various external autocrine/paracrine factors in representing normal melanocyte homeostatic functions modulating its viability, proliferation, differentiation, dendricity, migration, and melanogenic processes. This vitiligo map identifies known inducers/triggers of vitiligo onset and progression that cultivate a microenvironment for melanocyte disappearance, real or functional. This map describes the molecular mechanisms of currently utilized clinical and experimental treatments of vitiligo that facilitate repigmentation.

Nuclear hormone receptor functions in keratinocyte and melanocyte homeostasis, epidermal carcinogenesis and melanomagenesis

Skin homeostasis is maintained, in part, through regulation of gene expression orchestrated by type II nuclear hormone receptors in a cell and context specific manner. This group of transcriptional regulators is implicated in various cellular processes including epidermal proliferation, differentiation, permeability barrier formation, follicular cycling and inflammatory responses. Endogenous ligands for the receptors regulate actions during skin development and maintenance of tissue homeostasis. Type II nuclear receptor signaling is also important for cellular crosstalk between multiple cell types in the skin. Overall, these nuclear receptors are critical players in keratinocyte and melanocyte biology and present targets for cutaneous disease management.

The clinical significance of 25OH-Vitamin D status in celiac disease

Reduced bone mineral density is frequently found especially in adult celiac disease (CD) and dietary guidelines favor vitamin D supplementation in adults and children with CD. Vitamin D serum levels were investigated in CD populations in order to challenge its routine supplementation. Israeli (61), Spanish (59), CD children (groups 1 and 5, respectively) were compared to children with nonspecific abdominal pain (56), their parents (84) and Spanish adult CD patients (22) (group 2, 3, 4, respectively). 25(OH)-vitamin D was checked by LIAISON chemiluminescent immunoassays. Groups 5 and 1 had the highest levels compared to groups 4 and 3 with the lowest levels. The levels in groups 1 and 2 were comparable. Concerning 25(OH)-vitamin D sera levels, only the difference between group 5 and 4 was statistically significant (30.3 ± 12.3 and 20.2 ± 10.5 ng/ml, respectively p=0.003). When vitamin D was splitted above and below 20 ng/ml level, 54.5% of Spanish adult CD had vitamin D deficiency compared to 16.9% of the local CD children (p=0.001). 29.6% of group 2 had deficient levels compared to their parents with 50% (p=0.019). In conclusion, Vitamin D sera levels negatively correlate with age. Thus, mainly adult CD population should be assessed for vitamin D levels and supplemented accordingly.

Freckling promoted by topical tacalcitol in a Japanese boy with left eyelid vitiligo

Vitiligo is an acquired disorder in which the loss of melanocytes results in depigmented patches. Topical tacalcitol, a vitamin D(3) analog, is occasionally used to treat vitiligo. We report a case of a 7-year-old Japanese boy who showed moderate repigmentation and worsened freckles after using topical tacalcitol to treat a vitiligo lesion on and around the left eyelid. Topical tacalcitol might have induced and worsened the freckles, because the changes occurred during treatment. Dermatologists should be aware that topical application of tacalcitol to the cheeks can cause freckling and worsen existing freckles, in predisposed children, as described here.

Vitiligo: an update on current pharmacotherapy and future directions

INTRODUCTION

Vitiligo is a common pigmentary skin disorder, characterized by the appearance of white macules on the skin, mucosal or hair. Treatment is often a tough challenge and involves a wide range of therapies.

AREAS COVERED

This review focuses on available first- and second-line pharmacological treatments for vitiligo. In particular, the mechanisms of action, the main indications, the efficacy and the most important side effects are reviewed. Moreover, a brief discussion is provided, regarding other nonpharmacological treatments, such as phototherapy and surgical options, due to their importance and successful outcomes in vitiligo treatment. Finally, a concise overview regarding the future directions in vitiligo therapy is presented.

EXPERT OPINION

The promising outcomes reported here demonstrate that it is possible to achieve a satisfactory and often stable repigmentation of vitiligo lesions. Topical corticosteroids, calcineurin inhibitors, phototherapy and photochemotherapy represent the first-line therapeutic options, due to their safety and efficacy, whereas vitamin D analogues, targeted phototherapy, oral corticosteroids and surgery should be used as second-line therapies. Other therapies, such as antioxidants, can be used in association with other therapeutic options, whereas depigmenting agents should be used only in cases of extensive vitiligo, recalcitrant to other treatments.

The inflammatory response of keratinocytes and its modulation by vitamin D: the role of MAPK signaling pathways

The hormonal form of vitamin D, calcitriol, and its analogs are known for their beneficial effect in the treatment of inflammatory skin disorders. Keratinocytes play a role in epidermal inflammatory responses invoked by breeching of the epidermal barrier, by infectious agents and by infiltrating immune cells. We studied the role of calcitriol in the initiation of keratinocyte inflammatory response by the viral and injury mimic polyinosinic-polycytidylic acid (poly(I:C)) and in its maintenance by tumor-necrosis-factor α (TNFα) and investigated the role of the mitogen-activated protein kinase cascades in these processes and their regulation by calcitriol. The inflammatory response of human HaCaT keratinocytes to poly(I:C) or TNFα was assessed by measuring mRNA levels of 13 inflammation-related molecules by real-time PCR microarray and by in-depth investigation of the regulation of interleukin 8, intercellular-adhesion-molecule 1, and TNFα expression. We found that while calcitriol had only a minor effect on the keratinocyte response to poly(I:C) and a modest effect on the early response (2 h) to TNFα, it markedly attenuated the later response (16-24 h) to TNFα. The expression of CYP27B1, the enzyme responsible for calcitriol production, was marginally increased by poly(I:C) and markedly by TNFα treatment. This pattern suggests that while allowing the initial keratinocyte inflammatory response to proceed, calcitriol contributes to its timely resolution. Using pharmacological inhibitors we found that while the p38 MAPK and the extracellular signal-regulated kinase have only a minor role, c-Jun N-terminal kinase plays a pivotal role in the induction of the pro-inflammatory genes and its modulation by calcitriol.

Treatment of vitiligo vulgaris with the combination therapy of topical steroid and vitamin D3 compound

We report here two cases of vitiligo vulgaris successfully treated with the combination therapy of topical steroid and vitamin D3 compound and currently maintained by vitamin D3 analog without any adverse effects: skin atrophy, striae or telangiectasia on the exposed areas. The best-known mechanism of topical vitamin D3 analog is the enhancement of keratinocytes differentiation and anti-proliferative effects. Vitamin D3 analog is also reported to suppress T-cell mediated immunity, T-cell skin recruitment, and skin infiltration via down-regulating cutaneous lymphocyte antigen expression. Furthermore, vitamin D3 compounds are known to influence melanocyte maturation and differentiation and also to up-regulate melanogenesis. Autoreactive lymphocytes against melanocytes are one of the causes. Topical vitamin D3 analog may control vitiligo itself, however stronger immunosuppressive effects of topical corticosteroid may contribute to rapid re-pigmentation suppressing auto-reactive lymphocytes. The topical combination therapy is a simple, effective and safe option for vitiligo vulgaris in sun-exposed areas.

Vitiligo: a comprehensive overview Part II: treatment options and approach to treatment

Vitiligo is a common skin disorder that results in depigmentation. With the appropriate management, many patients can minimize disease progression, attain repigmentation, and achieve cosmetically pleasing results. There are numerous medical and surgical treatments aimed at repigmentation; therapies for depigmentation are available for patients with recalcitrant or advanced disease. The use of cosmetics at all stages of treatment may be vital to the patient's quality of life. Understanding all the available options helps choose the appropriate treatment plan and tailor it to your patient. Part II of this two-part series on vitiligo discusses the indications for, evidence behind, and adverse effects associated with many of the therapies used for vitiligo. Both conventional medical and surgical options are discussed in addition to several alternative and promising new therapies.

Genetic Ancestry, Skin Reflectance and Pigmentation Genotypes in Association with Serum Vitamin D Metabolite Balance

BACKGROUND

Lower serum vitamin D (25(OH)D) among individuals with African ancestry is attributed primarily to skin pigmentation. However, the influence of genetic polymorphisms controlling for skin melanin content has not been investigated. Therefore, we investigated differences in non-summer serum vitamin D metabolites according to self-reported race, genetic ancestry, skin reflectance and key pigmentation genes (SLC45A2 and SLC24A5).

MATERIALS AND METHODS

Healthy individuals reporting at least half African American or half European American heritage were frequency matched to one another on age (+/- 2 years) and sex. 176 autosomal ancestry informative markers were used to estimate genetic ancestry. Melanin index was measured by reflectance spectrometry. Serum vitamin D metabolites (25(OH)D₃, 25(OH)D ₂ and 24,25(OH)₂D₃) were determined by high performance liquid chromatography (HPLC) tandem mass spectrometry. Percent 24,25(OH)₂D₃ was calculated as a percent of the parent metabolite (25(OH)D₃). Stepwise and backward selection regression models were used to identify leading covariates.

RESULTS

Fifty African Americans and 50 European Americans participated in the study. Compared with SLC24A5 111^Thr homozygotes, individuals with the SLC24A5 111^Thr/Ala and 111^Ala/Ala genotypes had respectively lower levels of 25(OH)D₃ (23.0 and 23.8 nmol/L lower, p-dominant=0.007), and percent 24,25(OH)₂D₃ (4.1 and 5.2 percent lower, p-dominant=0.003), controlling for tanning bed use, vitamin D/fish oil supplement intake, race/ethnicity, and genetic ancestry. Results were similar with melanin index adjustment, and were not confounded by glucocorticoid, oral contraceptive, or statin use.

CONCLUSIONS

The SLC24A5 111^Ala allele was associated with lower serum vitamin 25(OH)D₃ and lower percent 24,25(OH)₂D₃, independently from melanin index and West African genetic ancestry.

Environmental pathways to autoimmune diseases: the cases of primary biliary cirrhosis and multiple sclerosis

The pathways leading to autoimmunity remain enigmatic despite numerous lines of experimental inquiry and epidemiological evidence. The mechanisms leading to the initiation and perpetuation of specific diseases such as primary biliary cirrhosis (PBC) or multiple sclerosis (MS) remain largely enigmatic, although it is established that a combination of genetic predisposition and environmental stimulation is required. The growing number of genome-wide association studies and the largely incomplete concordance for autoimmune diseases in monozygotic twins concur to support the role of the environment (including infectious agents and chemicals) in the breakdown of tolerance leading to autoimmunity through different mechanisms. In the present article we illustrate the current hypotheses related to an environmental impact on the onset of PBC and MS as two representative conditions investigated with complementary approaches. Indeed, while a role of post-translational antigen modifications has been proposed for MS, this field remain unexplored in PBC where, conversely, most evidence is gathered from geoepidemiology and experimental data on xenobiotics or infectious agents.