Experience with calcipotriol as adjunctive treatment for vitiligo in patients who do not respond to PUVA alone: a preliminary study

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.

Serum 25-Hydroxy Vitamin D Levels and Association of Vitamin D Receptor Gene Polymorphisms in Vitiligo

BACKGROUND

The role of vitamin D deficiency and vitamin D receptor (VDR) gene polymorphisms has been established in many autoimmune diseases, including vitiligo, but the result is still controversial.

OBJECTIVES

The aim of this study was to investigate the serum vitamin D levels in vitiligo patients and to compare the association of VDR gene polymorphisms in vitiligo patients and healthy controls.

METHODS

We collected the data of age, sex, serum 25-hydroxy vitamin D (25[OH]D) level, thyroid autoantibodies, disease duration, types of vitiligo, family history and the affected body surface area of vitiligo from 172 patients. And we analyzed the VDR gene polymorphisms in 130 vitiligo and 453 age-sex-matched control subjects.

RESULTS

The mean serum level of 25(OH)D in 172 vitiligo patients was 18.75 ± 0.60 ng/mL, which had no significant difference with a mean serum value of 25(OH)D in the Korean population. However, there were significant differences according to the duration of the disease and family history. Also, there were no significant differences in the genotypic and allelic distributions of 37 examined SNPs of VDR gene between vitiligo patients and healthy controls.

CONCLUSION

Serum level of 25(OH)D in vitiligo patients was not significantly different from the mean serum value of the Korean population. Also, there were no significant differences in the genotypic distributions of VDR gene between vitiligo patients and healthy controls.

Characteristics of bakuchiol - the compound with high biological activity and the main source of its acquisition - Cullen corylifolium (L.) Medik

The article presents the characteristics of bakuchiol - a natural compound valuable in cosmetology and pharmacology. The only source for obtaining this specific meroterpenic phenol is the fruit of the species Cullen corylifolium (Psoralea corylifolia). Bakuchiol has recently been playing a significant role in cosmetology as a "natural substitute" for retinol, free of side effects.Clinical studies confirm valuable cosmetological properties of bakuchiol, such as anti-ageing, anti-pigmentation and anti-acne effects. Scientific research has also shown valuable pharmacological properties of bakuchiol, such as anti-cancer, hepatoprotective, cardioprotective, hypoglycemic, hypolipemic, and antidepressant. In addition, antioxidant, anti-inflammatory and antimicrobal activities of bakuchiol, valuable from the point of view of both cosmetology and therapy, have also been confirmed.A separate part of the article is devoted to the botanical, chemical and pharmacological characteristics of the species C. corylifolium as the main source for obtaining bakuchiol.

Nonpsoriatic Uses of Calcipotriol

Background:

Calcipotriol is a synthetic vitamin D3 analog that binds to vitamin D receptors in epidermal cells. In vitro studies have shown that calcipotriol stimulates terminal cell differentiation and has antiproliferative effects. In vivo, calcipotriol has been shown to reduce the number of cycling epidermal cells. Calcipotriol also has less effect on calcium metabolism than calcitriol, which is the natural, bioactive, 1,25-dihydroxyvitamin D3.

Objective:

These properties make calcipotriol an ideal candidate for the topical treatment of hyperproliferative skin disorders. While it has been approved for topical use in psoriasis, its potential for use in other dermatological disorders has not yet been fully investigated.

Conclusion:

This survey of the literature suggests that calcipotriol may show promise in the treatment of other conditions involving abnormal keratinization and hyperproliferation of epidermal cells. While some of these disorders are rare, and therefore difficult to study, further study into the nonpsoriatic uses of calcipotriol may be rewarding.

Off-label uses of topical vitamin D in dermatology: a systematic review

BACKGROUND

Topical vitamin D is approved by the US Food and Drug Administration for the treatment of psoriasis but is also used off-label in the treatment of a variety of cutaneous diseases despite a lack of evidence-based guidelines.

OBJECTIVE

The objective of this study was to provide evidence-based clinical guidelines for the off-label use of topical vitamin D in the treatment of dermatologic disease.

METHODS

A systematic literature review was conducted via the MEDLINE, Embase, and CENTRAL databases for off-label uses of topical vitamin D analogues in the treatment of dermatologic disease other than psoriasis. The data were synthesized, and evidence-based recommendations were rendered according to the highest level of evidence available.

RESULTS

A total of 165 articles met the inclusion criteria. A moderate to strong recommendation was given for the use of topical vitamin D in combination with corticosteroids and phototherapy in vitiligo and as monotherapy for various ichthyoses, morphea, pityriasis alba, prurigo nodularis, and polymorphous light eruption. There is evidence showing that topical vitamin D is ineffective in the treatment of actinic keratosis, seborrheic keratosis, lichen planus, seborrheic dermatitis, alopecia areata, chemotherapy-induced alopecia, and hypertrophic scars.

CONCLUSION

Topical vitamin D analogues have an important role in the off-label treatment of dermatologic disease, but higher quality studies are still required.

Treatment of localized non-segmental vitiligo with intradermal 5-flurouracil injection combined with narrow-band ultraviolet B: a preliminary study

BACKGROUND

Several treatment modalities had been used for the treatment of vitiligo but the optimal treatment has not yet been identified.

AIM

To evaluate the efficacy and safety of intradermal injection of 5-flurouracil (5-FU) combined with narrow-band ultraviolet B (NB-UVB) as a treatment option for vitiligo.

PATIENTS AND METHODS

The study included 60 vitiligo patients with overall symmetrical lesions affecting less than 30% of body surface area. For each patient, one side of the body was treated with NB-UVB alone (control side) while the other side was treated with NB-UVB therapy in addition to intradermal injection of 5-FU (50 mg/ml), 0.01-0.02 ml per injection with 1 cm apart in skin of vitiligo, every 2 weeks for 4 months.

RESULTS

The overall repigmentation was significantly higher in the 5-FU side compared with control side in all body parts (p < 0.001) except for the acral lesions where the difference was not significant (p = 0.561). No systemic side effects of 5-FU were detected, and the majority of the patients reported pain during injections.

CONCLUSIONS

Intradermal 5-FU injection in combination with NB-UVB could be considered as a simple, safe, tolerable and cheap technique for treatment of vitiligo. It shortens the duration of NB-UVB therapy and improves the outcome, repigmentation. Longer follow-up is needed.

Vitiligo treatment options: An evolving scenario

Sequential displays of several treatment options for vitiligo have been scanned from the literature, and are presented here. A few of the medical modalities have been resigned to history, whereas others have become customary in clinical practice. There has also been a recent surge of interest in the surgical treatment of this disease. Accordingly, this has been appraised and summarized. Special attention has been given to prevalent medical modalities so that they may be effectively utilized by those currently in practice.

Combination of narrow band UVB and topical calcipotriol for the treatment of vitiligo

BACKGROUND

Narrow band ultraviolet B (NB-UVB) phototherapy has been used successfully for the treatment of vitiligo. Recently, topical calcipotriol has also been claimed to be effective, either as monotherapy or as a part of combination therapies.

OBJECTIVE

The aim of the present study was to compare the clinical efficacy of NB-UVB and NB-UVB plus topical calcipotriol in the treatment of vitiligo.

METHODS

NB-UVB treatment was given to 24 patients with generalized vitiligo three times weekly. Topical calcipotriol cream was only applied to the lesions located on the right side of the body. Treatment was continued for 6 months. Treatment efficacy was evaluated by determining the average response rates of the lesions at 3-month intervals.

RESULTS

The average response rates of patients receiving combination of NB-UVB plus calcipotriol and NB-UVB alone were 51 +/- 19.6% and 39 +/- 18.9%, respectively. The median cumulative UVB dose and number of UVB exposures for initial repigmentation were 6345 mj/cm(2) (range; 2930-30980) and 18 (range; 12-67) for the combination therapy, and 8867.5 mj/cm(2) (range; 2500-30980) and 24 (range; 15-67) for the narrow band UVB therapy, respectively.

CONCLUSIONS

These findings indicate that concurrent topical calcipotriol potentates the efficacy of NB-UVB in the treatment of vitiligo. This combination not only provides earlier pigmentation with lower total UVB dosage and less adverse UVB effects, but also reduces the duration and cost of treatment as well.

Tacalcitol and narrow-band phototherapy in patients with vitiligo

BACKGROUND

Vitiligo is a skin disease characterized by loss of normal pigmentation in the skin. Several treatments exist but none is really effective. Recently, perturbations of calcium homeostasis in vitiliginous epidermis have been described.

AIM

Based on these findings, the aim of this prospective, randomized, open-label study was to compare the effectiveness of narrow-band ultraviolet B (NB-UVB) phototherapy alone and the combination of NB-UVB and topical application of the vitamin D(3) analogue tacalcitol in the treatment of vitiligo.

METHODS

In total, 32 subjects with generalized vitiligo and symmetrical lesions were enrolled in the study. Subjects were instructed to apply tacalcitol ointment daily to the lesion on the side randomly selected to receive combination therapy. All subjects received NB-UVB phototherapy on a twice-weekly schedule.

RESULTS

Addition of topical tacalcitol to NB-UVB treatment improved the extent of repigmentation and increased the response rate in patients with vitiligo compared with NB-UVB treatment alone.

CONCLUSION

Application of tacalcitol ointment in combination with twice-weekly NB-UVB phototherapy is an effective alternative treatment for patients with generalized vitiligo.

Narrow-band ultraviolet B as monotherapy and in combination with topical calcipotriol in the treatment of vitiligo

Vitiligo is a common, idiopathic, acquired, depigmenting disease characterized by loss of normal melanin pigments in the skin. The most interesting treatment methods for extensive vitiligo involve psoralen plus ultraviolet A (PUVA) therapy and ultraviolet (UV)-B phototherapy, particularly narrow-band UV-B. In this randomized and comparative study, we investigated the safety and efficacy of narrow band ultraviolet B as monotherapy and in combination with topical calcipotriol in the treatment of generalized vitiligo. Of the 40 vitiligo patients enrolled in the study, 15 were treated with the calcipotriol plus narrow-band UV-B (NBUVB) and 25 with narrow band UV-B alone. The patients were randomized into two NBUVB treatment groups. The first group, consisting of 24 patients (all male), received only NBUVB treatment; the second group, consisting of 13 patients (all male) applied 0.05% topical calcipotriol ointments twice daily. Both groups were irradiated with NBUVB (311 nm). In the NBUVB group, the percentage of the body surface affected was reduced from 27.21 +/- 10.41% to 16.25 +/- 8.54% after a mean of 30 treatment sessions. The mean repigmentation percentage was 41.6 +/- 19.4%. In clinical evaluation (moderate and marked/complete response was accepted as an effective treatment), 19 patients (19/24; 79.17%) had clinically good results. In the NBUVB plus calcipotriol group, the percentage of the body surface affected was reduced from 23.35 +/- 6.5% to 13.23 +/- 7.05% after a mean of 30 treatment sessions. The mean repigmentation percentage was 45.01 +/- 19.15%. In clinical evaluation (moderate and marked/complete response was accepted as an effective treatment), 10 patients (10/13; 76.92%) had clinically good results. Statistically significant intragroup reductions from the baseline percentage of the body surface affected were seen at the endpoint of treatment for the two treatment groups (P < 0.001). However, there was no statistically significant difference between the two treatment groups at the end of therapy with respect to the reduction of repigmentation rates (P > 0.05). The present study reconfirmed the efficacy of NBUVB phototherapy in vitiligo. It can be a therapeutic option considered in the management of patients with vitiligo. However, addition of topical calcipotriol to NBUVB did not show any advantage.

Narrow-band UVB311 nm vs. broad-band UVB therapy in combination with topical calcipotriol vs. placebo in vitiligo

BACKGROUND

Recently, it has been shown that UVB phototherapy may be more effective than UVA in the treatment of vitiligo. Currently, however, no studies have compared the efficacy of UVB311 nm and broad-band UVB therapy. Calcipotriol has recently been reported to be effective adjunctive treatment for vitiligo, enhancing the efficacy of 8-methoxypsoralen plus UVA (PUVA) therapy.

METHODS

Ten patients were enrolled in the study; nine completed the 12 months of therapy. The upper part of the body was treated twice weekly with UVB311 nm and the lower part with broad-band UVB. Calcipotriol was applied onto the vitiligo lesions of the right side of the body and placebo on the left side. Repigmentation was documented by photography, planimetry, and Vitiligo Disease Activity (VIDA) score. The quality of life was measured by the Dermatology Life Quality Index (DLQI).

RESULTS

After 7-16 weeks, six of the nine patients showed initial repigmentation on the side treated with UVB311 nm. After 6 months of treatment, none of the patients showed repigmentation on the areas treated with broad-band UVB, which prompted us to apply UVB311 nm all over the body. At the end of 12 months, two patients showed > 75% repigmentation, two showed 51-75%, two showed 26-50%, and three showed 0-25%. In all patients with progressive vitiligo (seven of the nine patients), disease activity was stopped. Remarkably, vitiligo lesions treated with calcipotriol initially showed delayed repigmentation compared with control areas; however, there was no therapeutic difference between calcipotriol and placebo, both in combination with UVB311 nm, by the end of the study. The DLQI score improved significantly by an average of 28%. Conclusion UVB311 nm therapy was effective in the treatment of vitiligo, whereas broad-band UVB had no effect. Combination with calcipotriol ointment was not superior to UVB311 nm monotherapy. The quality of life significantly improved with narrow-band UVB311 nm phototherapy.

No additional effect of topical calcipotriol on narrow-band UVB phototherapy in patients with generalized vitiligo

BACKGROUND/PURPOSE

There is no definite cure for vitiligo; however, treatment responses with photobiological modalities are quite acceptable. Of all these, narrow-band UVB phototherapy was proposed rather recently. Calcipotriol has been shown to have stimulating activity on melanogenesis besides immunomodulatory and anti-inflammatory effects. This study was performed to determine whether adding topical calcipotriol to narrow-band UVB phototherapy enhances the efficacy of treatment.

METHODS

In this prospective, single-blinded (investigator), right-left comparison clinical study, 20 patients with generalized vitiligo were enrolled. Symmetrical lesions with similar sizes, bilaterally distributed on arms, legs, hands, feet or trunk were selected as reference lesions. In addition to narrow-band UVB, totally 96 treatment sessions, received two or three times weekly, the patients were asked to apply 0.005% topical calcipotriol on the selected side of the reference lesions twice daily. Then, they were monitored at the end of every 24-session interval.

RESULTS

Cosmetically acceptable repigmentation was observed in 55% (11/20) of the patients without taking calcipotriol into account. There was statistically significant better response on the side that calcipotriol was not applied at the 24th session (P < 0.05). No statistically significant difference was found between the calcipotriol-treated and non-treated sides at 48th, 72th, and 96th sessions (P > 0.05).

CONCLUSION

Our data confirm that, narrow-band UVB phototherapy is effective by itself in vitiligo, and show that adding topical calcipotriol does not improve treatment outcome.

Topical calcipotriene and narrowband ultraviolet B in the treatment of vitiligo

BACKGROUND

Treatment of vitiligo, despite significant advances made in the past few years, remains to be a challenge. Narrowband ultraviolet (NB-UVB) has emerged as an important therapeutic option for this condition.

OBJECTIVE

To evaluate whether the combination of calcipotriene ointment and NB-UVB could enhance the efficacy of NB-UVB alone.

METHODS

An open, bilateral comparison study was performed in 20 patients with symmetrical vitiligo between August 2001 and October 2002. All patients received NB-UVB three times per week. Calcipotriene ointment was applied to lesions on the left side of the body. Response was graded visually as significant (66-100% repigmentation), moderate (26-65%), mild (10-25%), and minimal (< 10%).

RESULTS

Seventeen patients (six females, 11 males) completed the study. Eight patients (8/17=47%) had significant repigmentation after 67-180 treatments, six patients (35%), one patient (6%), and two patients (12%) had moderate, mild, and minimal repigmentation after 40-160, 57, and 14-21 treatments, respectively. Nine of the 17 patients had an appreciably better improvement on the NB-UVB and calcipotriene side by 29-114 treatments. In six of these patients, differences were still observed at the end of the study period. No side effects were noted.

CONCLUSION

Combination therapy of topical calcipotriene and NB-UVB is a therapeutic option that could be considered in the management of patients with vitiligo.

New Treatment Modalities for Vitiligo

The development of effective treatment modalities for vitiligo is dependent on an understanding of the events leading to depigmentation. However, the exact pathogenesis of vitiligo is still mostly unknown. Abnormalities in both humoral and cell-mediated immunity have been documented in vitiligo patients and they present a basis for using immunomodulating agents, such as corticosteroids and macrolide immunomodulators, in the treatment of vitiligo. Macrolide immunomodulators, such as tacrolimus and pimecrolimus, which can be used topically, are known as topical immunomodulators (TIMs). TIMs inhibit the action of calcineurin, and consequently inhibit T-cell activation and the production of various cytokines; this is considered the working mechanism of action of TIMs in vitiligo. Several small studies and case reports on the use of TIMs in vitiligo have been published so far. Tacrolimus achieves better results on the face and neck than on other body areas. Particular advantages of TIMs are safety in treating these areas because of lack of skin atrophy and good tolerability. The incidence of application site adverse events in vitiligo seems to be lower than in the treatment of atopic dermatitis. On the face and neck, TIMs may become a useful tool in the treatment of adults and children with vitiligo despite possibly lower efficacy than topical corticosteroids. Further, larger, controlled clinical studies are warranted to determine the definite role of TIMs as monotherapy or in combination with other modalities in the treatment of vitiligo.

Melanin pigmentation in mammalian skin and its hormonal regulation

Cutaneous melanin pigment plays a critical role in camouflage, mimicry, social communication, and protection against harmful effects of solar radiation. Melanogenesis is under complex regulatory control by multiple agents interacting via pathways activated by receptor-dependent and -independent mechanisms, in hormonal, auto-, para-, or intracrine fashion. Because of the multidirectional nature and heterogeneous character of the melanogenesis modifying agents, its controlling factors are not organized into simple linear sequences, but they interphase instead in a multidimensional network, with extensive functional overlapping with connections arranged both in series and in parallel. The most important positive regulator of melanogenesis is the MC1 receptor with its ligands melanocortins and ACTH, whereas among the negative regulators agouti protein stands out, determining intensity of melanogenesis and also the type of melanin synthesized. Within the context of the skin as a stress organ, melanogenic activity serves as a unique molecular sensor and transducer of noxious signals and as regulator of local homeostasis. In keeping with these multiple roles, melanogenesis is controlled by a highly structured system, active since early embryogenesis and capable of superselective functional regulation that may reach down to the cellular level represented by single melanocytes. Indeed, the significance of melanogenesis extends beyond the mere assignment of a color trait.

Calcipotriene and corticosteroid combination therapy for vitiligo

Corticosteroids and photochemotherapy, using a combination of psoralen and ultraviolet A (PUVA) exposure, are the most widely prescribed therapies for vitiligo. These treatments are not uniformly effective and many patients have inadequate responses. Calcipotriene has been shown to be effective in adults and children with psoriasis when used as monotherapy and in combination with corticosteroids and phototherapy. We hypothesized that since the mechanisms of action for calcipotriene and corticosteroids are different, patients may develop more repigmentation with a combination of the two agents, while decreasing the side effects from both agents. Twelve patients with vitiligo (average age 13.1 years) were advised to use topical corticosteroids in the morning and topical calcipotriene in the evening. Of the 12 patients, 83% responded to therapy, with an average of 95% repigmentation by body surface area. Four of the patients who responded had previously failed trials of topical corticosteroids alone. All of the patients in this group had repigmentation. Eyelid and facial skin responded best to this therapy. None of the patients had adverse reactions to the treatment. Our results show that topical calcipotriene in combination with corticosteroids can repigment vitiligo, even in those patients who were previous topical corticosteroid failures.

Combined Excimer Laser and Topical Tacrolimus for the Treatment of Vitiligo: A Pilot Study

BACKGROUND

Vitiligo is an acquired skin disorder that is characterized by well-defined, often symmetric white patches. Although current therapeutic modalities are directed toward increasing melanocyte melanin production, few treatment modalities address the immunologic nature of the disease.

OBJECTIVE

To determine whether excimer laser, a known therapeutic modality, in combination with tacrolimus, a topical immunomodulator, accelerate response time and/or improve the degree of response in patients with this disorder.

METHODS

Eight subjects diagnosed with vitiligo were recruited to participate in this institutional review board-approved double-blind, placebo-controlled study. Twenty-four symmetric vitiliginous patches (elbows, knees) from eight subjects received excimer laser treatment three times per week for 24 treatments or 10 weeks. Additionally, topical tacrolimus 0.1% ointment (Protopic) and placebo (Aquaphor) were applied to randomized patches (left or right) twice daily throughout the length of the trial. Vitiliginous patches were monitored with photographs at baseline, every 2 weeks, and 6 months after treatment. Biopsies were performed on subjects with significant results.

RESULTS

Twenty vitiliginous patches from six subjects qualified for evaluation. Fifty percent of patches treated with combination excimer laser and tacrolimus achieved a successful response (75% repigmentation) compared with 20% for the placebo group. Subjects who responded successfully repigmented faster (19%) with combination therapy compared with excimer laser alone. Additionally, three subjects experienced transient hyperpigmentation in lesions treated with combination therapy.

CONCLUSION

Combining topical immunomodulators with known phototherapeutic modalities may represent a key advancement in the treatment of disease.

Is the combination of calcipotriol and PUVA effective in vitiligo?

OBJECTIVE

The objective was to compare the effectiveness of psoralen plus ultraviolet A (PUVA) and the combination of PUVA and topical calcipotriol in the treatment of vitiligo.

BACKGROUND

There are several reports on the response rate of patients with vitiligo treated with the combination of PUVA and calcipotriol or calcipotriol alone.

SUBJECTS AND METHODS

Twenty-two patients with generalized vitiligo were taken into the study. PUVA treatment was applied on a twice-weekly schedule. Calcipotriol cream was applied to one of the two symmetrical lesions of each patient twice daily.

RESULTS

Our results showed that the addition of topical calcipotriol to PUVA treatment did not lead to a significant increase in response rate of patients with vitiligo compared with PUVA treatment alone.

Photo(chemo) therapy for vitiligo

Vitiligo has always been difficult to treat. Several modes of treatment are available, but the therapeutic effect varies greatly, and rarely does one achieve complete repigmentation. One of the most efficient treatment methods is photo(chemo) therapy. Already in ancient Egypt, vitiligo lesions were treated with extracts of the Ammi maius plant followed by exposure to the sun. This principle is at the basis of the photochemotherapy or PUVA therapy, whereby UVA irradiations are given 2 h after administration of 8-methoxypsoralen, a photosensitizer. Another efficient treatment form is UVB phototherapy, particularly narrow-band UVB. This not only gives good therapeutic results but also has the advantage of eliminating the need for a photosensitizer. All these treatments must be applied for many months to be efficient. They can also be combined with various surgical skin-grafting techniques. A newer approach is targeted UVB phototherapy, whereby xenon-chloride lasers or monochromatic excimer light is used.

Differentiation of murine melanocyte precursors induced by 1,25-dihydroxyvitamin D3 is associated with the stimulation of endothelin B receptor expression

The effects of 1,25-dihydroxyvitamin D3 on the differentiation of immature melanocyte precursors were studied. The NCC-/melb4 cell line is an immature melanocyte cell line established from mouse neural crest cells. 1,25-Dihydroxyvitamin D3 inhibited the growth of NCC-/melb4 cells at concentrations higher than 10(-8) m. That growth inhibition was accompanied by the induction of tyrosinase and a change in L-3,4-dihydroxyphenylalanine reactivity from negative to positive. Electron microscopy demonstrated that melanosomes were in more advanced stages after 1,25-dihydroxyvitamin D3 treatment. In primary cultures of murine neural crest cells, L-3,4-dihydroxyphenylalanine-positive cells were increased after 1,25-dihydroxyvitamin D3 treatment. These findings indicate that 1,25-dihydroxyvitamin D3 stimulates the differentiation of immature melanocyte precursors. Moreover, immunostaining and reverse transcription-polymerase chain reaction analysis revealed that endothelin B receptor expression was induced in NCC-/melb4 cells following treatment with 1,25-dihydroxyvitamin D3. The induction of endothelin B receptor by 1,25-dihydroxyvitamin D3 was also demonstrated in neural crest cell primary cultures, but not in mature melanocytes. The expression of microphthalmia-associated transcription factor was induced in NCC-/melb4 cells treated with 1,25-dihydroxyvitamin D3 and endothelin 3, but not by 1,25-dihydroxyvitamin D3 alone, suggesting that endothelin 3 may stimulate the expression of the microphthalmia-associated transcription factor gene after binding to the endothelin B receptor induced by 1,25-dihydroxyvitamin D3. These findings suggest a regulatory role for vitamin D3 in melanocyte development and melanogenesis, and may also explain the working mechanism of vitamin D3 in the treatment of vitiligo.