Effects of six compounds with different chemical structures on melanogenesis.

Several chemical compounds can restore pigmentation in vitiligo through mechanisms that vary according to disease etiology. In the present study, we investigated the melanogenic activity of six structurally distinct compounds, namely, scopoletin, kaempferol, chrysin, vitamin D3, piperine, and 6-benzylaminopurine. We determined their effectiveness, toxicity, and mechanism of action for stimulating pigmentation in B16F10 melanoma cells and in a zebrafish model. The melanogenic activity of 6-benzylaminopurine, the compound identified as the most potent, was further verified by measuring green fluorescent protein concentration in tyrp1 a: eGFP (tyrosinase-related protein 1) zebrafish and mitfa: eGFP (microphthalmia associated transcription factor) zebrafish and antioxidative activity. All the tested compounds were found to enhance melanogenesis responses both in vivo and in vitro at their respective optimal concentration by increasing melanin content and expression of TYR and MITF. 6-Benzyamino-purine showed the strongest re-pigmentation action at a concentration of 20 µmol·L-1in vivo and 100 µmol·L-1in vitro, and up-regulated the strong fluorescence expression of green fluorescent protein in tyrp1a: eGFP and mitfa: eGFP zebrafish in vitro. However, its relative anti-oxidative activity was found to be very low. Overall, our results indicated that 6-benzylaminopurine stimulated pigmentation through a direct mechanism, by increasing melanin content via positive regulation of tyrosinase activity in vitro, as well as up-regulating the expression of the green fluorescent protein in transgenic zebrafish in vivo.

Effect of different types of therapeutic trauma on vitiligo lesions.

New treatment modalities for vitiligo acting by changing certain cytokines and metalloproteinases are newly emerging. The aim of this work is to To assess the efficacy of trichloroacetic acid (TCA) chemical peel, dermapen, and fractional CO2 laser in treatment of stable non-segmental vitiligo and to detect their effects on IL-17 and MMP-9 levels. Thirty patients with stable vitiligo were recruited in a randomized controlled study. They were randomly categorized into three equal groups. Group 1: TCA peel, Group 2: dermapen machine, and Group 3: Fractional CO2 laser. Skin biopsies were taken from treated areas and from control areas for which MMP-9 and IL-17 tissue levels were measured using ELISA. The 30 vitiligo patients had low basal tissue MMP-9 levels and high baseline IL-17 tissue levels. As regards the three different used modalities, all of them caused rise in MMP-9 as well as IL-17 levels and almost their levels were much more elevated with repetition of the previously mentioned traumatic procedures. TCA 25% peel proved to be the most effective modality both clinically and laboratory and it can be used prior or with other conventional therapies in the treatment of vitiligo.

Heme oxygenase-1 expression protects melanocytes from stress-induced cell death: implications for vitiligo.

To study protection of melanocytes from stress-induced cell death by heme oxygenases during depigmentation and repigmentation in vitiligo, expression of isoforms 1 and 2 was studied in cultured control and patient melanocytes and normal skin explants exposed to UV or bleaching agent 4-TBP. Similarly, expression of heme oxygenases was followed in skin from vitiligo patients before and after PUVA treatment. Single and double immunostainings were used in combination with light and confocal microscopic analysis and Western blotting. Melanocyte expression of heme oxygenase 1 is upregulated, whereas heme oxygenase 2 is reduced in response to UV and 4-TBP. Upregulation of inducible heme oxygenase 1 was also observed in UV-treated explant cultures, in skin of successfully PUVA-treated patients and in melanocytes cultured from vitiligo non-lesional skin. Heme oxygenase encoding genes were subsequently cloned to study consequences of either gene product on cell viability, demonstrating that HO-1 but not HO-2 overexpression offers protection from stress-induced cell death in MTT assays. HO-1 expression by melanocytes may contribute to beneficial effects of UV treatment for vitiligo patients.

[Effect of zibuganshenfang on the expression and activity of tyrosinase on B16 cells].

OBJECTIVE: ZiBuGanShenFang (ZBGSF) is a traditional herbal formula, which has showed an outstanding therapeutic effect on vitiligo clinically. Our aim is to investigate the influence of ZBGSF drug serum on the expression and activity of Tyrosinase in B16 cells, explore the mechanism of ZBGSF on Vitiligo treatment further. METHOD: tyrosinase activity was measured by zymological methods, western blotting and RT-PCR were used to measure the protein content and mRNA level of tyrosinase and related proteins, respectively. RESULT: ZBGSF drug serum had no effect on the proliferation of B16 cells. But it could promote Tyrosinase activity significantly and increase protein content and mRNA level of tyrosinase and related proteins in B16 cells. CONCLUSION: Promoting the expression of tyrosinase protein and mRNA may be the elementary basis of ZBGSF on Vitiligo treatment.

A complex prescription for vitiligo activates mitochondrial ATP synthase-6 expression in B-16 murine melanoma cells.

A complex prescription (CP) used traditionally for the treatment of vitiligo was prepared from water extract of eight plant materials. To study the mechanism of this preparation its effect on gene expression of B-16 murine melanoma cells was estimated using differential display method (DDRT-PCR). The results showed that the complex prescription was effective in activating the mitochondrial ATP synthase-6 (ATPase-6) gene expression in B-16 murine melanoma cells. This activity may play an important role in its treatment of vitiligo.

Topical pseudocatalase mousse and narrowband UVB phototherapy is not effective for vitiligo: an open, single-centre study.

We report an open single-centre trial to assess the efficacy of topical pseudocatalase mousse applied twice daily to the hands and face of vitiligo patients, in combination with twice-weekly suberythemogenic narrowband UVB phototherapy. The regime was generally safe and well tolerated, although several patients experienced mild transient skin rashes in association with application of the mousse and one patient suffered severe pruritus. The primary efficacy variable was the percentage change in area affected by vitiligo as assessed by digital interpretation of standardized photographs of the face and hands. There was no clear evidence of the efficacy of the regime and in fact a slight tendency overall to worsening of the patients' vitiligo.

Serum selenium levels and blood glutathione peroxidase activities in vitiligo.

It has recently been shown that patients with vitiligo can accumulate epidermal hydrogen peroxide (H2O2) in association with low catalase levels. This study examined serum selenium levels and blood glutathione peroxidase activities in 61 patients and controls. The results showed high serum selenium levels in 56% of the patients. As at least one isoform of glutathione peroxidase requires selenium for its activity, enzyme activities were also evaluated. The overall results were not significantly different compared with controls, but further age-related analysis of the data indicated significantly lower activities in patients up to 46 years. As glutathione peroxidase can also efficiently degrade H2O2, the results of this study could indicate an additional impaired H2O2 metabolism in vitiligo.