Clinical and Molecular Aspects of Vitiligo Treatments

Health-Related Quality of Life Burden Among Adults with Vitiligo: Relationship to Disease Severity and Disease Location

INTRODUCTION

Vitiligo was historically regarded as a cosmetic disorder; however, it is an autoimmune disease. As a visible condition, it affects patient well-being. We assessed the impact of disease severity, lesion location, and body surface area (BSA) affected on patient health-related quality of life (HRQoL).

METHODS

Retrospective data were from the Adelphi Real World Vitiligo Disease Specific Programme: a cross-sectional survey of physicians and their patients with vitiligo (10/2021-07/2022). Patient-reported outcomes were assessed by the Vitiligo-Specific Quality of Life Instrument (VitiQoL), Hospital Anxiety and Depression Scale (HADS), and EQ-5D-5L. The Work Productivity and Impairment Questionnaire (WPAI) questionnaire was used to assess disease-related impairment of daily activities. Data were stratified by physician-reported disease severity, presence/absence of vitiligo on the face, and BSA percentage affected.

RESULTS

In total, 1388 patients were included. Mean (SD) VitiQoL, HADS depression, and anxiety scores were higher for those with severe disease [40.5 (26.1), 5.2 (4.4), and 6.8 (4.7)] than those with mild [24.8 (18.8), 3.6 (3.8), 4.2 (3.8)] or moderate [27.1 (22.6), 3.8 (4.5), 4.3 (4.4)] disease. Patients with face affected reported higher VitiQoL [30.0 (22.3) versus 23.2 (19.3)], and HADS scores [depression, 4.3 (4.3) versus 3.2 (3.9); anxiety, 5.0 (4.3) versus 3.8 (3.9)] than those without. Patients with ≥ 5% BSA affected had higher VitiQoL, depression and anxiety scores [27.9 (21.8), 4.0 (4.4), and 4.5 (4.2)] than those with 0-5% [24.6 (19.7), 3.4 (3.7), and 4.3 (4.1)]. Patients with severe vitiligo, facial lesions, or ≥ 5% BSA reported higher activity impairment. Mean EQ-5D-5L-utility score was approximately 0.9 regardless of disease severity or total BSA affected.

CONCLUSIONS

These data demonstrate the impact disease severity can have on HRQoL and daily activities for patients with vitiligo. Lesions that are more severe, on the face, or covering a greater BSA are more often associated with poorer outcomes and activity impairment. These data also highlight the potential insensitivity of commonly used HRQoL measures and a need for more sensitive disease-specific measures.

Capsaicin combined with stem cells improved mitochondrial dysfunction in PIG3V cells, an immortalized human vitiligo melanocyte cell line, by inhibiting the HSP70/TLR4/mTOR/FAK signaling axis

BACKGROUND

Vitiligo is a common autoimmune skin disease. Capsaicin has been found to exert a positive effect on vitiligo treatment, and mesenchymal stem cells (MSCs) are also confirmed to be an ideal cell type. This study aimed to explore the influence of capsaicin combined with stem cells on the treatment of vitiligo and to confirm the molecular mechanism of capsaicin combined with stem cells in treating vitiligo.

METHODS AND RESULTS

PIG3V cell proliferation and apoptosis were detected using CCK-8 and TUNEL assays, MitoSOX Red fluorescence staining was used to measure the mitochondrial ROS level, and JC-1 staining was used to detect the mitochondrial membrane potential. The expression of related genes and proteins was detected using RT‒qPCR and Western blotting. Coimmunoprecipitation was used to analyze the protein interactions between HSP70 and TLR4 or between TLR4 and mTOR. The results showed higher expression of HSP70 in PIG3V cells than in PIG1 cells. The overexpression of HSP70 reduced the proliferation of PIG3V cells, promoted apoptosis, and aggravated mitochondrial dysfunction and autophagy abnormalities. The expression of HSP70 could be inhibited by capsaicin combined with MSCs, which increased the levels of Tyr, Tyrp1 and DCT, promoted the proliferation of PIG3V cells, inhibited apoptosis, activated autophagy, and improved mitochondrial dysfunction. In addition, capsaicin combined with MSCs regulated the expression of TLR4 through HSP70 and subsequently affected the mTOR/FAK signaling pathway CONCLUSIONS: Capsaicin combined with MSCs inhibits TLR4 through HSP70, and the mTOR/FAK signaling pathway is inhibited to alleviate mitochondrial dysfunction and autophagy abnormalities in PIG3V cells.

Antioxidant mechanisms of mesenchymal stem cells and their therapeutic potential in vitiligo

Vitiligo is a skin pigmentation disorder caused by melanocyte damage or abnormal function. Reac-tive oxygen species Reactive oxygen species can cause oxidative stress damage to melanocytes, which in turn induces vitiligo. Traditional treatments such as phototherapy, drugs, and other methods of treatment are long and result in frequent recurrences. Currently, mesenchymal stem cells (MSCs) are widely used in the research of various disease treatments due to their excellent paracrine effects, making them a promising immunoregulatory and tissue repair strategy. Furthermore, an increasing body of evi-dence suggests that utilizing the paracrine functions of MSCs can downregulate oxidative stress in the testes, liver, kidneys, and other affected organs in animal models of certain diseases. Addition-ally, MSCs can help create a microenvironment that promotes tissue repair and regeneration in are-as with oxidative stress damage, improving the disordered state of the injured site. In this article, we review the pathogenesis of oxidative stress in vitiligo and promising strategies for its treatment.

The possible role of Wnt/β-catenin signalling in vitiligo treatment

Vitiligo is a common chronic skin disease which has an adverse impact on patients' life. Its pathogenesis is complex, involving autoimmunity and oxidative stress (OS). Autoimmunity leads to the loss of epidermal melanocytes and the formation of the depigmented patches of the disease. Treatment of vitiligo should control the exaggerated immune response to arrest the progress of active disease, and then promote melanocytes to repigmentation. Wnt/β-catenin signalling pathway has been of recent interest in vitiligo. Wnt/β-catenin signalling pathway is downregulated in vitiligo. Upregulation of Wnt/β-catenin signalling possibly control vitiligo autoimmune response by protecting melanocyte from OS damage, inhibiting CD8+ T cell effector cell differentiation and enhancing Treg. Wnt/β-catenin signalling plays a critical role in the melanocyte regeneration by driving the differentiation of melanocyte stem cells (McSCs) into melanocytes. Promoting Wnt/β-catenin signalling can not only arrest the progress of active disease of vitiligo but also promote repigmentation. Some of the main effective therapies for vitiligo are likely to work by activating Wnt/β-catenin signalling. Agents that can enhance the effect of Wnt/β-catenin signalling may become potential candidates for the development of new drugs for vitiligo treatment.

Non-invasive Imaging Techniques for Monitoring Cellular Response to Treatment in Stable Vitiligo

Punch grafting procedures, where small pieces of normal skin are transplanted into stable vitiligo patches, results in repigmentation in only half of patients treated, yet the factors that determine whether a patient responds to treatment or not are still unknown. Reflectance confocal microscopy (RCM) is adept at visualizing melanocyte migration and epidermal changes over large areas while multiphoton microscopy (MPM) can capture metabolic changes in keratinocytes. With the overall goal of identifying optical biomarkers for early treatment response, we followed 12 vitiligo lesions undergoing punch grafting. Dendritic melanocytes adjacent to the graft site were observed before clinical evidence of repigmentation in treatment responsive patients but not in treatment non-responsive patients, suggesting that the early visualization of melanocytes is indicative of a therapeutic response. Keratinocyte metabolic changes in vitiligo skin adjacent to the graft site also correlated with treatment response, indicating that a keratinocyte microenvironment that more closely resembles normal skin is more hospitable for migrating melanocytes. Taken together, these studies suggest that successful melanocyte transplantation requires both the introduction of new melanocytes and modulation of the local tissue microenvironment.

Intralesional methotrexate in the treatment of localized vitiligo: A pilot study

BACKGROUND/OBJECTIVES

Vitiligo is an immune-mediated skin disorder that targets epidermal melanocytes leading to the appearance of depigmented skin patches. Different treatment modalities have been reported with varied efficacy. We tried to evaluate the safety and efficacy of intralesional methotrexate in treating localized areas of vitiligo.

METHODS

Thirty participants with localized patches of vitiligo were recruited. They were treated with intralesional injections of methotrexate every 2 weeks for a maximum of six sessions. At the end of the study, the degree of repigmentation was categorized into: excellent improvement (>75% repigmentation), good improvement (50%-75% repigmentation), fair improvement (25%-50% repigmentation) and poor improvement (<25% repigmentation).

RESULTS

We included 7 males (23.3%) and 23 females (76.7%). Their mean age was 33.6 ± 8.6 years. The duration of the disease ranged from 1 to 22 years. Four patients had a family history of vitiligo. At the end of the study, there was a highly statistically significant improvement (p < 0.001) after treatment regarding repigmentation.

CONCLUSIONS

This study showed that intralesional methotrexate is a safe and effective treatment option for patients with localized vitiligo lesions. Further studies on a larger scale are needed to evaluate the long-term effects of treatment and detect the ideal dose to be injected.

Roflumilast enhances the melanogenesis and attenuates oxidative stress-triggered damage in melanocytes

BACKGROUND

The management of vitiligo is challenging due to limited treatment options, and therapeutic strategy varies according to the active or stable stage of vitiligo. PDE4 inhibitor has been used to treat various skin diseases, but the efficacy in vitiligo treatment is mixed.

OBJECTIVE

In this study, we aimed to investigate whether roflumilast, a PDE4 inhibitor, induces melanogenesis and attenuates oxidative stress-triggered damage in melanocytes, and if so, what is the mechanism.

METHODS

Melanin content assay, qRT-PCR, western blotting, ELISA, immunofluorescence assays, immunohistochemistry, small interfering RNA, flow cytometry, and transmission electron microscopy were employed.

RESULTS

Our results demonstrated that roflumilast alone only slightly increased melanogenesis, however, the combination of roflumilast and forskolin could boost cAMP levels, hence promoting melanogenesis more significantly. Moreover, roflumilast attenuated H₂O₂-induced apoptosis and mitochondrial morphological changes in melanocytes by reducing ROS levels. Furthermore, roflumilast activated AhR/Nrf2 pathway via cAMP whereas AhR silencing blocked roflumilast-induced Nrf2 nuclear translocation and reversed the inhibitory effect of roflumilast on H₂O₂-induced ROS production. Finally, we observed that the lesional skin of active vitiligo patients exhibited higher PDE4 expression levels.

CONCLUSION

roflumilast enhances the melanogenesis effect of forskolin and protects melanocytes from H₂O₂-induced apoptosis by cAMP/AhR/Nrf2-activated ROS inhibition, highlighting its therapeutic potential in vitiligo treatment.

Interleukin 1α and interleukin 18 in patients with vitiligo - Results of a case-control study

INTRODUCTION

Vitiligo is a depigmenting disorder resulting from loss of functional melanocytes in the skin. Variety of inflammatory mediators participate in the regulation of melanogenesis in melanocytes: interleukin-18 (IL-18), interleukin-33, granulocyte-macrophage colony stimulating factor, interferon-γ, prostaglandin E2 have the effect of promoting melanogenesis, while interleukin-1 (IL-1), interleukin-4, interleukin-6, interleukin-17 and tumor necrosis factor can inhibit melanogenesis.

AIM

Evaluation of IL-1α and IL-18 levels in peripheral blood in patients with vitiligo compared to healthy controls.

MATERIALS AND METHODS

Fifty patients aged 18-81 with vitiligo participated in the study. The control group consisted of 38 healthy people. Venous blood samples were obtained from each participant. Serum IL-1α and IL-18 concentrations were determined using the enzyme-linked immunoabsorbent assay (ELISA).

RESULTS

Among patients with vitiligo, the mean concentration of IL-1α was 0.13 (± 0.535) pg/mL, while in the control group it was 0.51 (± 1.51). There were no statistically significant differences in IL-1α concentrations between patients in the study group compared to the control group (p > 0.05). In the study group, the mean IL-18 concentration was 141.05 (± 136.33) pg/mL vs 137.33 (± 105.83) pg/mL in the controls. There were no statistically significant differences in IL-18 concentrations between patients in the study group compared to the controls (p > 0.05). In the Spearman correlation test, no correlation was confirmed between IL1α and IL-18 concentrations in the group of patients with vitiligo vs healthy people.

CONCLUSIONS

There is no correlation between Il-1 and Il-18 concentration in the blood sera of patients with vitiligo.

Comparison of NB-UVB combination therapy regimens for vitiligo: A systematic review and network meta-analysis

BACKGROUND

Vitiligo was an autoimmune disease and some guidelines for the management of vitiligo encouraged the use of NB-UVB combination therapies to enhance repigmentation.

OBJECTIVES

To compare the effectiveness of current NB-UVB combination regimen at the improvement in repigmentation through a systematic review and network meta-analysis.

METHODS

We searched the electronic databases for randomized controlled trials related to NB-UVB combination therapy for vitiligo till October 2022. STATA15.0 software was applied to carrying out data analysis.

RESULTS

A total of 28 eligible studies involving 1194 participants were enrolled in the analysis. The NMA results revealed that compared with NB-UVB, carboxytherapy [OR = 32.35, 95% CI (1.79, 586.05)], Er: YAG laser+ topical 5% 5-FU [OR = 10.74, 95% CI (4.05, 28.49)], needling/micro-needling [OR = 3.42, 95% CI (1.18, 9.88)], betamethasone intramuscular injection [OR = 3.08, 95% CI (1.17, 8.13)], topical tacrolimus [OR = 2.54, 95% CI (1.30, 4.94)], and oral Chinese herbal medicine compound [OR = 2.51, 95% CI (1.40, 4.50)] integrated with NB-UVB were more efficacious in excellent to complete repigmentation response rate (≥75%). Besides, NB-UVB+ Er: YAG laser+ topical 5% 5-FU [OR = 0.17, 95% CI (0.04, 0.67)] and NB-UVB+ needling/micro-needling [OR = 0.24, 95% CI (0.06, 0.88)] were less likely evaluated as ineffective repigmentation response (≤25%).

CONCLUSIONS

All combination therapies ranked higher than NB-UVB monotherapy in inducing successful repigmentation and avoiding failed treatment in patients with vitiligo. Comprehensive consideration, NB-UVB+ Er: YAG laser+ topical 5% 5-FU and NB-UVB+ needling/microneedling would be the preferred therapeutic approaches.

Efficacy and safety of combined fractional ablative CO2 laser and 5 fluorouracil in the treatment of acral vitiligo: An open, uncontrolled study

BACKGROUND

Acral lesions of vitiligo are most likely recalcitrant to the known lines of treatment. Ablative fractional CO₂ has shown efficacy in treatment of vitiligo in combination with other modalities.

METHODS

Thirty non-segmental vitiligo patients with acral lesion were included in the study. Each patient was subjected to fractional Carbon Dioxide Laser Treatment followed by application of 5 fluorouracil (5FU) cream for five consecutive days. Evaluation was done 3 weeks from the start of treatment and 12 weeks after the last treatment session using VESTA score, evaluation of patients' photos by blinded investigation in addition to patients' satisfaction scores.

RESULTS

Patients showed significant improvement of Vitiligo extent score for a target area (VESTA) score and developed considerable degree of repigmentation as assessed by blinded investigators.

CONCLUSION

The combination of fractional ablative CO₂ and 5FU is an effective and safe procedure for the treatment of acral vitiligo with promising results offering patients a new therapeutic window.

Clinical efficacy analysis of 110 cases of childhood vitiligo with non-surgical combined therapy

BACKGROUND

Vitiligo has a negative effect on children's physical and psychological health. Few studies have examined long-term treatment efficacy for childhood vitiligo. Therefore, we evaluated the long-term effectiveness of non-surgical combination therapy in pediatric patients with vitiligo and analyzed factors that affect its efficacy.

METHODS

Pediatric patients (⩽12 years) with vitiligo who were treated with topical corticosteroids/topical calcineurin inhibitors and phototherapy for 12 months were retrospectively studied. Short-term systemic corticosteroids were administered according to individual clinical conditions. All lesions were photographed to assess repigmentation at 3-month intervals. Clinical data, the treatment effectiveness, and factors affecting the therapeutic effect were analyzed.

RESULTS

Overall, 110 children (51 [53.6%] girls; mean [SD] age, 7.1 ± 3.0 years; 104 [94.5%] with activity status) were treated for a mean period of 23.13 ± 14.03 months (range, 5-86 months). The overall >50% repigmentation rate was 64.5%. A longer duration of treatment was associated with a higher repigmentation rate (X² _trend = 36.229, P < .001). The vitiligo disease activity score at the first visit was positively correlated with the overall repigmentation rate (r_s = 0.301, P = .001).

CONCLUSIONS

Treatment lasting longer than 1 year is recommended in children with vitiligo. The best repigmentation effect can be achieved by combination therapy in the rapid progression stage.

Efficacy of narrow band UVB with or without OMP in stabilization of vitiligo activity in skin photo-types (III-V): A double-blind, randomized, placebo-controlled, prospective, multicenter study

BACKGROUND

NB-UVB has long been the vitiligo management pillar with capability of achieving the main treatment outcomes; repigmentation and stabilization. Its stabilizing effect in dark skin has been debatable. However, randomized controlled trials regarding NB-UVB ability to control disease activity are lacking.

PURPOSE

To assess stabilizing effect of NB-UVB in comparison to systemic corticosteroids, the mainstay in vitiligo stabilization, in skin photo-types (III-V).

METHODS

This is a multicenter, placebo-controlled, randomized, prospective study. Eighty patients with active nonsegmental vitiligo (NSV) (Vitiligo disease activity (VIDA) ≥2) were randomized to either NB-UVB and placebo (NB-placebo) or NB-UVB and dexamethasone oral mini-pulse (OMP) therapy (NB-OMP) for 6 months. Sixty four patients completed the study, 34 in the NB-OMP group and 30 in the NB-placebo group. Patients were evaluated fortnightly according to presence or absence of symptoms/signs of activity.

RESULTS

In spite of earlier control of disease activity observed in the NB-OMP group, it was comparable in both groups by the end of the study period. Disease activity prior to therapy, but not extent, was found to influence control of activity in both groups. Thus, NB-UVB is a safe sole therapeutic tool in vitiligo management. Not only does it efficiently achieve repigmentation, but also it is a comparable stabilizing tool for systemic corticosteroids in spite of slightly delayed control.

CONCLUSION

NB-UVB is the only well-established vitiligo therapy that can be used solely whenever corticosteroids are contraindicated or immune-suppression is unjustified. Nonetheless, its combination with corticosteroids expedites response and improves compliance.

UVB phototherapy in the treatment of vitiligo: State of the art and clinical perspectives

Vitiligo is a chronic pigmentary skin disorder that results in white, hypopigmented macules and patches. It causes a considerable psychological and emotional burden on the affected individuals and their families. Several therapeutic options have been employed in vitiligo including topical and oral drugs, surgical techniques, and phototherapy which is considered the cornerstone treatment. Different wavelengths and modalities are available, but narrowband UVB (NB-UVB) is considered the safest and the most effective phototherapy alternative. NB-UVB acts on multiple steps in vitiligo pathogenesis, and it is capable of inducing stabilization and repigmentation of vitiligo lesions. Technological advances have led to the development of both new phototherapy devices and new medical and surgical therapeutic options that can be combined with phototherapy to achieve optimal results. There is no standard treatment, and individual patient and disease characteristics should be considered. We review the current evidence in what concerns UVB phototherapy for vitiligo treatment, including novel combination treatments that may help to provide the best care for these patients.

Surgical procedures and innovative approaches for vitiligo regenerative treatment and melanocytorrhagy

Surgical treatments for vitiligo are a safe and effective treatment modality for select patients with vitiligo. Many techniques of vitiligo surgery exist, each with unique advantages and disadvantages. We reviewed the various surgical therapies and innovative approaches for vitiligo regenerative treatment reported in the literature. Surgical therapies can be subdivided into tissue grafting methods and cellular grafting methods. Tissue grafting methods mainly include mini punch grafts, suction blister roof grafts, and hair follicle grafts. Cellular grafting methods include cultured and non-cultured treatments. The efficacy needs to be improved largely due to the poor proliferation and quality of the autologous melanocytes. Rho-associated protein kinase inhibitor enhances primary melanocyte culture proliferation from vitiligo patients to prevent apoptosis. Innovative approaches using stem cell methods could prove invaluable in developing a novel cell therapy for patients suffering from vitiligo. We succeeded in inducing melanin pigmentation in mice skin in vivo using our human induced pluripotent stem cell-derived melanocytes. In addition, we reviewed melanocytorrhagy, detachment and transepidermal loss of melanocytes, and melanocyte-related adhesion molecules. These adhesion molecules include epithelial cadherin, discoidin domain receptor tyrosine kinase 1, glycoprotein non-metastatic melanoma protein B, macrophage migration inhibiting factor, 17β-hydroxysteroid dehydrogenase 1, and E26 transformation-specific 1.

Evaluation of the association between platelet tests and thyroid stimulating hormone levels in patients with vitiligo

OBJECTIVE

Vitiligo is a common dermatological disease of unknown cause and progressing with depigmentation and affects approximately 1% of the world population. In the study, we aimed to compare plateletcrit (PCT), mean platelet volume (MPV), platelet (PLT), and thyroid-stimulating hormone (TSH) values in vitiligo patients.

MATERIAL AND METHODS

We retrospectively evaluated the medical data of 100 patients who were admitted to the dermatology outpatient clinic between January 2020 and December 2021 with a diagnosis of vitiligo. The control group was retrospectively constituted from medical records of 190 healthy individuals. PCT, MPV, PLT, and TSH levels of both groups were compared statistically.

RESULTS

A total of 190 participants (100 vitiligo patients and 90 healthy volunteers) were included in the study. The mean age of the patient group was 38.62±1.62, while the mean age of the control group was 41.52±1.54. There were no differences between the two groups in terms of age and gender. It was found that the mean MPV value in the patient group was lower than the control group (p=0.00). PLT and PCT values were significantly higher in the patient group than the control group (p=0.00, p=0.01, respectively). There was no statistically significant difference between the two groups in terms of TSH (p>0.05). A negative correlation between MPV and PLT values in the patient group (r=-0.218, p=0.029), and a negative correlation between MPV and TSH (r=-0.218, p=0.029). -0.230, p=0.021).

CONCLUSION

In the study, a comparison of the PCT, MPV, and PLT levels showed a difference between both groups, but no differences in TSH levels. To clarify these results, comprehensive studies with more samples are needed.

The Promising Role of Chemokines in Vitiligo: From Oxidative Stress to the Autoimmune Response

Vitiligo is a common chronic autoimmune skin disorder featured with depigmented patches and underlying destruction of melanocytes in the lesional skin. Multiple factors and mechanisms have been proposed for the etiopathogenesis of vitiligo, among which oxidative stress has been widely accepted as a key factor in initiating melanocyte loss. The altered redox status caused by oxidative stress, including the overproduction of reactive oxygen species (ROS) and the decreased activity of the antioxidant system in the skin, surrenders the resistance of melanocytes to exogenous or endogenous stimuli and eventually impairs the normal defense mechanism, leading to the absence of melanocytes. Considering the important role of innate and adaptive immunity in vitiligo, there is mounting evidence revealing an association between oxidative stress and autoimmunity. Since the significant changes of chemokines have been documented in vitiligo in many recent studies, it has been suggested that ROS-mediated chemotactic signals are not only the biomarkers of disease progression and prognosis but also are involved in the pathogenesis of vitiligo by facilitating the innate and adaptive immune cells, especially melanocyte-specific T cells, trafficking to the lesional areas of vitiligo. In this review, we discuss the interaction between oxidative stress and autoimmune response orchestrated by chemokines, including CXCL16-CXCR6 axis, CXCL9/CXCL10-CXCR3 axis, and other altered chemokines in vitiligo, and we also try to provide insight into potential therapeutic options through targeting these pathways.

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.

Vitiligo: What's old, what's new

Vitiligo is an acquired pigmentary disorder afflicting 0.5-2% of the world population for both sexes and all races with a capricious and unpredictable course. It has a complex etiology and varies in its manifestation, progression and response to treatment. Even if the precise aetiology and pathobiology of the disease are complex and still debated, recent evidence supports that vitiligo is a T CD8+ cell-mediated autoimmune disease triggered by oxidative stress. To date no clinical, biological and histological criteria allow us to establish the prognosis with certainty. The choice of the best therapy for adult and childhood vitiligo is based on various factors, such as the patient's age, psychological condition and expectations, distribution and extension of skin lesions, type of vitiligo (stable or not) and availability and cost of therapeutic options. Since vitiligo has a deep psychological impact on patients and their quality of life, treating the disease is very important. As dermatologists, we have important goals in the treatment of vitiligo patients: stabilization of the disease progression, repigmentation of the lesions and especially the persistence of the aforementioned repigmentation. Although several medical and surgical therapeutic options have been proposed, no definite cure has yet been developed and the long-term persistence of repigmentation is unpredictable. We review the different therapeutic options with particular attention on the recurrence rate.

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.

A novel mouse model to evaluate neuropeptide Y-mediated melanocyte pathology

Vitiligo is an autoimmune disease characterized by depigmented patches of skin due to loss of the pigment-producing melanocytes. No cure exists for vitiligo. The available treatments are inefficient for many patients, suggesting that universal treatment approaches may be inappropriate. Deeper understanding of the mechanistic basis for variability in vitiligo aetiologies is necessary. Genetic mutations in neuropeptide Y (NPY), a widely distributed protein, are associated with increased NPY expression and increased susceptibility for vitiligo. NPY is also upregulated in the circulation and lesional skin of some vitiligo patients. However, the contributions of NPY to melanocyte pathology are not understood, and presently there are no models with which to investigate this possibility. In this study, we employed NPY-overexpressing mice to explore the role of NPY in melanocyte dysfunction. Our results show that NPY overexpression induces progressive hair greying (depigmentation) due to premature depletion of follicular melanocyte stem cells. Additionally, NPY transcripts and protein are elevated in the skin and melanocytes of these mice, respectively, suggesting that these effects may be mediated locally. Together, these results suggest that supraphysiological levels of NPY in the skin can induce melanocyte dysfunction, thus identifying this mouse line as a novel model to study NPY-mediated melanocyte pathology.

Strategies to Develop a Suitable Formulation for Inflammatory Skin Disease Treatment

Skin barrier functions, environmental insults, and genetic backgrounds are intricately linked and form the basis of common inflammatory skin disorders, such as atopic dermatitis, psoriasis, and seborrheic dermatitis, which may seriously affect one’s quality of life. Topical therapy is usually the first line of management. It is believed that successful topical treatment requires pharmaceutical formulation from a sufficient dosage to exert therapeutic effects by penetrating the stratum corneum and then diffusing to the target area. However, many factors can affect this process including the physicochemical properties of the active compound, the composition of the formulation base, and the limitations and conditions of the skin barrier, especially in inflammatory skin. This article briefly reviews the available data on these issues and provides opinions on strategies to develop a suitable formulation for inflammatory skin disease treatment.

A review of Nigella sativa plant-based therapy in dermatology

Nigella sativa (N. sativa) is a widely used medicinal herb with a rich cultural and religious history in Unani, Ayurveda, Chinese, and Arabic medicine. N. sativa contains many natural bioactive agents including alkaloids, saponins, alpha-hederin, and thymoquinone that contribute to its broad range of benefits as a diuretic, bronchodilator, antihypertensive, antidiabetic, and analgesic. In addition, N. sativa possesses antimicrobial, anti-inflammatory, and antineoplastic effects, making it an interesting potential therapy for the treatment of dermatological conditions. This article reviews the current literature surrounding the pharmacological effects of N. sativa for the treatment of acne vulgaris, melanoma, vitiligo, atopic dermatitis, plaque psoriasis, and wound healing.

Stem Cell Therapy Offers a Possible Safe and Promising Alternative Approach for Treating Vitiligo: A Review

BACKGROUND

Normal skin pigmentation pattern is an extremely important component of the appearance of a person, as it can be a significant factor in the social context of any person. A condition known as vitiligo is caused by the death of melanocytes leading to pigmentation loss in the skin. This affects all races across the globe and sometimes leads to social avoidance as in some communities, it is stigmatized. Although there are different pathobiological processes suspected because of the different underlying causes of vitiligo, autoimmunity and oxidative stress are suspected to be the most probable ones.

OBJECTIVE

In this review, we present an overview of the underlying mechanisms causing and developing the disease. Also, some of the most successful treatments along with the clinical applications of Mesenchymal Stem Cells (MSCs) as a comprehensive approach for treating this condition will be covered.

RESULTS

Autoreactive CD8+ T-cells are the primary suspect considered to be responsible for the destruction of melanocytes. Therefore, topical use of autoimmune inhibitors including those derived from MSCs, thanks to their immune-modulatory properties, have been reported to be successful in the promotion of repigmentation. MSCs can suppress the proliferation of CD8+T via the NKG2D pathway while inducing T-cell apoptosis. The use of pharmacological agents for reducing cellular oxidative stress with the help of topical application of antioxidants and growth factors also have been in use. Intravenous administration of MSCs has been shown to regulate the level of reactive oxidative species (ROS) in a mice model. Growth factors derived from platelet-rich-plasma (PRP) or from MSCs caused rapid tissue regeneration.

CONCLUSIONS

Finally, MSC therapy also has been shown to stimulate the mobilization of healthy melanocytes, leading to successful repigmentation of skin lesions in vitiligo patients.

Involvement of adenylate cyclase/cAMP/CREB and SOX9/MITF in melanogenesis to prevent vitiligo

Vitiligo is autoimmune, acquired, idiopathic, chronic, and progressive de/hypopigmentary cutaneous condition that targets the cell-producing pigment called melanin. It binds to a thread of great disappointment and emotional stress in societies. Combining multiple stress-related theories like toxic compound accumulation, autoimmunity, mutations, altered cellular environment, infection, impaired migration/proliferation, and immunological mismatch of anti-melanocyte and self-reactive T-cells that cause melanocytes damage is formulated resulting in vitiligo. Vitiligo has an orphan status for drug synthesis. Still, different therapies are available, with topical steroids and narrow-band ultraviolet-B monotherapy being the most common treatments, others including medical, physical, or surgical, but not effective. Each modality has its baggage of disadvantages and side effects. Stimulation of the transcriptional process for melanogenesis is mainly achieved by the cAMP-dependent activation of several melanogenic genes by MITF. In this review, we summarized that cAMP encourages the expression of the enzyme tyrosinase, TYRP1, TYRP2, and most other biological effects of cAMP are mediated through the cAMP-dependent PKA pathway resulting in CREB phosphorylation. It has been shown that TYRP1 and 2 do not have cAMP response elements (CREs) in promoting regions; the regulation of these genes by cAMP occurs through the direct participation of MITF during melanogenesis. The available medicines, therefore, only provide symptomatic relief, but do not stop the disease progression. In addition, the treatment process needs to be changed; existing approaches need to be overlooked for patients who are suffering and therefore analyze its efficacy and safety to achieve a favorable risk-benefit ratio.

Dedifferentiation of human epidermal melanocytes in vitro by long-term trypsinization

Human epidermal melanocytes can be induced to form melanocyte spheroids and revert to immature characteristics by long-term trypsinization (LTT). To further explore the biological characteristics of melanocytes after LTT and to study the underlying mechanism. Melanocytes were subjected to long-term (2 h) trypsinization in this study, after which their viability, proliferation and autophagy were characterized. The expression of melanocyte markers [human melanoma black45 (HMB45), tyrosinase (TYR) and Nestin] was detected and relative expression levels of mRNAs encoding TYR, Nestin, c-Kit and microphthalmia-associated transcription factor (MITF) were determined. After LTT, more short spindle-shaped melanocytes appeared and viability assays demonstrated that most melanocytes survived that treatment but had decreased proliferation rates compared to the untreated controls. There was a significant increase in autophagy of melanocytes after LTT and the expression of TYR was decreased compared with untreated control melanocytes. There were no significant differences in the expression of HMB45 or Nestin between the two groups. Compared with untreated melanocytes, levels of message ribonucleic acid (mRNAs) encoding TYR, c-Kit and MITF were decreased after LTT, while Nestin mRNA levels were increased. These results clarified that Long-term treatment with trypsin causes the dedifferentiation of mature epidermal melanocytes in vitro.

Effects of autologous micrografts on stable bilateral vitiligo: A focus on hand lesions

Vitiligo is an autoimmune skin disorder characterized by depigmented patches of the skin associated with, among several factors, dysregulation and death of melanocytes. Currently, the treatment of vitiligo is based both on the arrest of the progression of active disease and on the stimulation of the skin repigmentation. The aim of this study was to assess the effects of autologous micrografts and narrowband ultraviolet B (NBUVB) phototherapy for skin repigmentation of patients with bilateral stable vitiligo. Autologous micrografts are derived from mechanical disaggregation of small pieces of the patient's own skin, while phototherapy is a strategy treatment already used. Twenty patients with stable bilateral vitiligo were treated, showing a mean percentage rate of 59.1% at baseline. Combined treatment by autologous micrografts and NBUVB was performed only on the lesions of the hands, and the clinical follow up was performed after 3 and 6 months by photographs taken under Wood's light. After 6 months, we classed 100% of patients as responders. We also reported a mean of repigmentation rate of 36.7% after 3 months and 64.6% after 6 months of treatment. In particular, six of the 20 patients reached a marked repigmentation rate (75-100%), four moderate (51-75%) and 10 mild (26-50%). No adverse effects were observed and no drugs were administrated as co-adjuvant therapy. These results are suggestive of a potential wide use of autologous micrografts associated with NBUVB phototherapy for the treatment of stable vitiligo.

Immunohistochemical study of perforin and apoptosis stimulation fragment ligand (FasL)in active vitiligo

Several studies demonstrated a major pathological role of melanocyte-specific cytotoxic CD8⁺ T cells in the pathogenesis of vitiligo. It has been suggested that apoptosis, rather than necrosis, is the mechanism of melanocyte depletion in vitiligo. The aim of this study was to evaluate the expression and distribution of perforin and apoptosis stimulation fragment ligand (FasL) in the epidermis and dermis of the perilesional and non-lesional skin of vitiligo patients in comparison to controls, to assess their possible role in mediating apoptosis in vitiligo. Twenty patients with active non-segmental vitiligo and 20 healthy controls were enrolled in the study. Skin biopsies were taken from perilesional and non-lesional skin of patients with vitiligo, as well as covered skin of controls. Immunostaining for perforin and FasL was performed and the quantitative analysis for the expression of perforin and FasL was carried out in the epidermis and dermis of biopsied specimens. Epidermal perforin, dermal perforin, epidermal FasL, dermal FasL were significantly higher in perilesional as well as non-lesional skin than controls. There was a statistically significant positive correlation between epidermal and dermal perforin in perilesional skin. There was a statistically significant positive correlation between epidermal and dermal perforin, as well as epidermal and dermal FasL in non-lesional skin. In conclusion, the significant expression of perforin and FasL in the epidermis and dermis of both perilesional and non-lesional skin of active vitiligo patients suggests the role of cytotoxic granules and apoptotic cell death pathways in the pathogenesis of active vitiligo.

Oral mycophenolate mofetil as a stabilizing treatment for progressive non-segmental vitiligo: results from a prospective, randomized, investigator-blinded pilot study

Dexamethasone oral mini-pulse (OMP) is commonly used to halt progression of non-segmental vitiligo (NSV). There is an unmet need for non-phototherapy, non-corticosteroid therapeutic options for stabilizing actively spreading NSV. To assess the efficacy of oral mycophenolate mofetil in stabilizing active NSV in comparison to OMP. In this prospective, randomized, investigator-blinded study, 50 patients of active vitiligo [baseline vitiligo disease activity (VIDA) score 4] were randomized into two groups in 1:1 ratio. Group A received oral dexamethasone (2.5 mg on two successive days a week) and group B received mycophenolate mofetil (up to 2 g) for 180 days with a treatment-free follow-up period of 90 days. Assessment was done using VIDA, number of new lesions in past 30 days, and Vitiligo Area Scoring Index (VASI). Arrest of disease progression was defined as the absence of any new lesions in past 30 days. Twenty-five patients received OMP (group A, 11 males, 14 females), and 25 received mycophenolate (group B, 12 males, 13 females). In both groups, Kruskal-Wallis revealed a significant trend for reduction in VIDA and the number of new lesions in last 30 days, over the treatment and follow-up duration when compared to baseline (p < 0.001). The first significant reduction in VIDA was noticed on 90th day in groups A and B (p < 0.001). In both groups, VIDA reduced significantly at the 180th day compared to baseline (p < 0.001, WMP), only to increase significantly at the 270th day (p < 0.001, WMP). VIDA in group B was marginally higher at 270 days than group A (p 0.03; Mann-Whitney). Eighteen and 17 patients achieved VIDA 2 + on the 180th day in groups A and B, respectively. The mean number of new lesions in last 30 days reduced significantly in both groups at the 180th day (p < 0.001) and 270th day [p < 0.001; Wilcoxon matched pairs (WMP)] when compared to baseline; but increased significantly at the 270th day compared to the 180th day (p 0.006 WMP). Twenty patients in group A and 18 patients in group B had arrest of the disease activity with treatment. Mean duration to arrest disease progression was 47.2 ± 12.1 days in group A, and 52.5 ± 9.3 days in group B; p 0.21. The difference between VASI at baseline and VASI at the 180 and 270th days was non-significant in both groups (p 0.18 WMP). Five patients in each group failed the respective treatments. Acne (n = 3), weight gain (n = 3), headache, insomnia and menstrual irregularity (n = 1 each) were the important adverse effects noted with dexamethasone pulse; whereas nausea (n = 6) and diarrhea (n = 4) were the commonest adverse effects noted with mycophenolate. Two patients in group B discontinued treatment because of leucopenia (n = 1) and transaminitis (n = 1) that resolved after the discontinuation of mycophenolate. Both OMP and mycophenolate mofetil halt actively spreading vitiligo, and have distinct adverse effect profiles. These should be offered in progressive vitiligo, especially in circumstances precluding the use of phototherapy. Relapse occurred significantly earlier with mycophenolate, and relapse rate was higher (though non-significant) than dexamethasone OMP. The repigmentation potential is minimal for both therapies. This study was approved by Institute Ethics Committee, and retrospectively registered with clinical trial registry of India (CTRI/2018/02/011,664).

The efficacy of fractional carbon dioxide laser combined with narrow-band ultraviolet B phototherapy for non-segmental vitiligo: a systematic review and meta-analysis

Fractional carbon dioxide (CO₂) laser has been used with conventional treatments for vitiligo, demonstrating more effectiveness compared with conventional treatments alone. Especially, fractional CO₂ laser combined with narrow-band ultraviolet B (NB-UVB) was shown to induce more improvement compared with NB-UVB monotherapy for treating stable non-segmental vitiligo. However, the effectiveness of fractional CO₂ laser plus NB-UVB for the treatment of non-segmental vitiligo remains controversial. Therefore, this study aimed to confirm the safety and efficacy of fractional CO₂ laser combined with NB-UVB compared with NB-UVB monotherapy in stable non-segmental vitiligo. We searched the data from different databases, including Cochrane, Embase, and PubMed up to January 2020. Four randomized controlled trials (RCTs) for comparison between fractional CO₂ laser plus NB-UVB and NB-UVB monotherapy in patients with stable non-segmental vitiligo were included. We performed meta-analyses for repigmentation improvement and patient satisfaction as well as subgroup analyses based on acral or non-acral vitiligo, according to the PRISMA guidelines. The combination treatment showed more superior results than NB-UVB monotherapy (≥ 75% repigmentation, RR 4.60, 95% CI 1.19-17.74; ≥ 50% repigmentation, RR 2.24, 95% CI 0.45-11.17; < 25% repigmentation, RR 0.81, 95% CI 0.60-1.08). Also, fractional CO₂ laser plus NB-UVB significantly improved acral and non-acral vitiligo compared with NB-UVB monotherapy (standard mean difference (SMD) 1.24, 95% CI 0.66-1.82; SMD 1.14, 95% CI 0.67-1.60, respectively), while it increased markedly patient satisfaction compared with NB-UVB monotherapy (SMD 1.12, 95% CI 0.66-1.58). Collectively, this meta-analysis suggested that fractional CO₂ laser combined with NB-UVB might be more effective for treating non-segmental vitiligo than NB-UVB monotherapy.

VIRdb: a comprehensive database for interactive analysis of genes/proteins involved in the pathogenesis of vitiligo

Vitiligo is a chronic asymptomatic disorder affecting melanocytes from the basal layer of the epidermis which leads to a patchy loss of skin color. Even though it is one of the neglected disease conditions, people suffering from vitiligo are more prone to psychological disorders. As of now, various studies have been done in order to project auto-immune implications as the root cause. To understand the complexity of vitiligo, we propose the Vitiligo Information Resource (VIRdb) that integrates both the drug-target and systems approach to produce a comprehensive repository entirely devoted to vitiligo, along with curated information at both protein level and gene level along with potential therapeutics leads. These 25,041 natural compounds are curated from Natural Product Activity and Species Source Database. VIRdb is an attempt to accelerate the drug discovery process and laboratory trials for vitiligo through the computationally derived potential drugs. It is an exhaustive resource consisting of 129 differentially expressed genes, which are validated through gene ontology and pathway enrichment analysis. We also report 22 genes through enrichment analysis which are involved in the regulation of epithelial cell differentiation. At the protein level, 40 curated protein target molecules along with their natural hits that are derived through virtual screening. We also demonstrate the utility of the VIRdb by exploring the Protein-Protein Interaction Network and Gene-Gene Interaction Network of the target proteins and differentially expressed genes. For maintaining the quality and standard of the data in the VIRdb, the gold standard in bioinformatics toolkits like Cytoscape, Schrödinger's GLIDE, along with the server installation of MATLAB, are used for generating results. VIRdb can be accessed through "http://www.vitiligoinfores.com/".

Combination of oral methotrexate and oral mini-pulse dexamethasone vs either agent alone in vitiligo treatment with follow up by dermoscope

This study aimed to compare the efficacy and safety of oral methotrexate (MTX) and oral mini-pulse (OMP) dexamethasone alone and in combination in the treatment of vitiligo. A total of 42 patients with vitiligo were included in the study. The patients were treated for three months and randomly assigned into three groups including 14 patients each: group A received oral MTX, group B received OMP dexamethasone, and group C received a combination of both. Follow-up was performed using digital photographs, Vitiligo European Task Force score, and dermoscopy. Disease extension significantly decreased in group C compared with that in groups A (P < .001) and B (P < .05). The frequency of intralesional pigmentation significantly increased (P < .05) in groups A and C and decreased (P < .05) in group B posttreatment noted using a dermoscope. Moreover, the frequency of micro-Koebner's phenomenon and starburst pattern significantly decreased (P < .05) in groups B and C and that of tapioca sago in group C only posttreatment.

Electrocautery Needling and the 308-nm Excimer Lamp: A Synergistic Combination for the Treatment of Stable Non-segmental Vitiligo

Introduction

Vitiligo is an acquired chronic depigmentation disorder caused by the destruction of melanocytes. Although various treatments have been proposed for the management of vitiligo, achieving repigmentation and preventing relapse remains challenging. The aim of the study was to evaluate the effectiveness of electrocautery needling (EC needling) as a treatment for stable non-segmental vitiligo and to determine if the effectiveness of this treatment could be enhanced by combining it with the 308-nm excimer lamp (excimer lamp).

Methods

Thirty patients with stable non-segmental vitiligo were enrolled in this self-controlled, non-blinded study. Three vitiligo lesions of similar size, location and disease duration were selected from each patient and randomly assigned to one of three groups treated weekly with EC needling, an excimer lamp or a combination of both (combination group), respectively. The effectiveness of treatment on the repigmentation percentage and the number of treatments required for initial pigmentation were assessed.

Results

There was no significant difference in the repigmentation percentage between the EC needling group and the excimer lamp group (P = 0.789). The mean number of treatments required for initial repigmentation was lower in the EC needling group than in the excimer lamp group (P = 0.049). The repigmentation percentage was significantly higher in the combination group than in the EC needling group (P = 0.027) and excimer lamp group (P = 0.005). Evidence of initial pigmentation was obtained earlier in lesions treated with the combination therapy than in lesions treated with excimer lamp therapy alone (P = 0.019). Vitiligo lesions on the face and neck regions showed the highest repigmentation percentage among all anatomical regions, whereas lesions on the hands and feet showed the worst treatment response.

Conclusion

Electrocautery needling monotherapy was effective in treating vitiligo, and its efficacy was enhanced when combined with the 308-nm excimer lamp. This combined approach to treat vitiligo is safe and helps increase patient compliance.

The enigma and challenges of vitiligo pathophysiology and treatment

Vitiligo is the most common acquired pigmentary disorder, which afflicts 0.5%-1% of the world population, and is characterized by depigmented skin patches resulting from melanocyte loss. Vitiligo has a complex etiology and varies in its manifestations, progression, and response to treatment. It presents as an autoimmune disease, evidenced by circulating melanocyte-specific antibodies, and association with other autoimmune diseases. However, autoimmunity may be secondary to the high oxidative stress in vitiligo skin and to intrinsic defects in melanocytes and their microenvironment, which contribute to aberrant stress response, neo-antigenicity, and susceptibility of melanocytes to immune attack and apoptosis. There is also a genetic predisposition to vitiligo, which sensitizes melanocytes to environmental agents, such as phenolic compounds. Currently, there are different treatment modalities for re-pigmenting vitiligo skin. However, when repigmentation is achieved, the major challenge is maintaining the pigmentation, which is lost in 40% of cases. In this review, we present an overview of the clinical aspects of vitiligo, its pathophysiology, the intrinsic defects in melanocytes and their microenvironment, and treatment strategies. Based on lessons from the biology of human melanocytes, we present our perspective of how repigmentation of vitiligo skin can be achieved and sustained.

Local heroes or villains: tissue-resident memory T cells in human health and disease

Tissue-resident memory T (T_RM) cells are increasingly associated with the outcomes of health and disease. T_RM cells can mediate local immune protection against infections and cancer, which has led to interest in T_RM cells as targets for vaccination and immunotherapies. However, these cells have also been implicated in mediating detrimental pro-inflammatory responses in autoimmune skin diseases such as psoriasis, alopecia areata, and vitiligo. Here, we summarize the biology of T_RM cells established in animal models and in translational human studies. We review the beneficial effects of T_RM cells in mediating protective responses against infection and cancer and the adverse role of T_RM cells in driving pathology in autoimmunity. A further understanding of the breadth and mechanisms of T_RM cell activity is essential for the safe design of strategies that manipulate T_RM cells, such that protective responses can be enhanced without unwanted tissue damage, and pathogenic T_RM cells can be eliminated without losing local immunity.

Differentiation of adipose-derived stem cells to functional CD105neg CD73low melanocyte precursors guided by defined culture condition

Background

The generation of functional human epidermal melanocytes (HEM) from stem cells provides an unprecedented source for cell-based therapy in vitiligo. Despite the important efforts exerted to obtain melanin-producing cells from stem cells, pre-clinical results still lack the safety and scalability characteristics essential for their translational application.

Methods

Here, we report a rapid and efficient protocol based on defined culture conditions capable of differentiating adult adipose-derived stem cells (ADSC) to scalable amounts of proliferative melanocyte precursors (PreMel) within 30 days. PreMel were characterized in vitro through qPCR, Western blot, flow cytometry, biochemical assays, and in vivo assays in immunocompromised mice (NOD.Cg-Prkdc^scid Il2rg^tm1Wjl/SzJ, or NSG).

Results

After 30 days of differentiation, the stem cell-derived PreMel were defined as CD105^neg CD73^low according to immunophenotypic changes in comparison with parental stem cell markers. In addition, expression of microphthalmia-associated transcription factor (MITF), active tyrosinase (TYR), and the terminal differentiation-involved premelanosome protein (PMEL) were detected. Furthermore, PreMel had the potential to synthesize melanin and package it into melanosomes both in vitro and in vivo in NSG mice skin.

Conclusions

This study proposes a rapid and scalable protocol for the generation of proliferative melanocyte precursors (PreMel) from ADSC. These PreMel display the essential functional characteristics of bona fide HEM, opening a new path for an autologous cellular therapy for vitiligo patients.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1364-0) contains supplementary material, which is available to authorized users.