Estudo comparativo morfofuncional de melanócitos em lesões de melasma

Amber photobiomodulation versus tranexamic acid for the treatment of melasma: protocol for a double-blind, randomised controlled trial

INTRODUCTION

Photobiomodulation (PBM) has been suggested as an alternative treatment for melasma. In vitro studies have shown PBM with amber light inhibits the tyrosinase enzyme, induces autophagy and reduces the melanin content, but randomised controlled clinical trials are still needed. This study aims to evaluate the efficacy of amber PBM (590 nm) in the treatment of melasma compared with liposomal tranexamic acid.

METHODS AND ANALYSIS

This study is a controlled, randomised, double-blind, non-inferiority trial. This study will be performed in two centres (Universidade Nove de Julho Facility, Campus Vergueiro, and Galache Odontology Clinic, São Caetano do Sul, both in São Paulo State, Brazil). The sample (54 participants) will be divided into two groups in a 1:1 ratio; one group will receive active PBM and a placebo cosmetic and the other will receive sham PBM and liposomal tranexamic acid. Women presenting facial melasma, aged 35-50 years, with skin phototypes II-IV, will be eligible for inclusion. Women who use oral contraceptives, intrauterine devices, hormone replacement or photosensitive drugs, those with autoimmune disease and those who have undergone facial treatments in the last 3 months will be excluded from the study. The participants will receive PBM weekly for 12 weeks and will use the cosmetic two times per day at home during this period. The severity of melasma will be evaluated through the Melasma Area and Severity Index (MASI) as the primary outcome; pigmentation of the epidermis evaluated by corneomelametry, the photographic records, the global diagnosis of the face and the quality-of-life questionnaire (Brazilian Portuguese version of the Melasma Quality of Life Questionnaire) will assessed as secondary outcomes. All assessments will be made before starting the study (week 0), mid-study at 6 weeks and at the completion of treatment (week 12). MASI will also be evaluated during follow-up (weeks 16 and 20). The data will be analysed based on the intention-to-treat analysis using a generalised mixed model, and α <0.05 will be considered statistically significant.

ETHICS AND DISSEMINATION

The protocol was approved by the Research Ethics Committee of Universidade Nove de Julho (5 332 384). All participants will fill out the patient informed consent form. The results obtained in this trial will be presented at conferences and submitted for publication.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT05326997).

Dermoscopic classification of melasma: Concordance study and correlation with the melanophages count

BACKGROUND

Melasma is a common hypermelanosis characterized by symmetrical brownish macules, especially on the face. Histologic analysis demonstrates increased epidermal and dermal melanin. Dermoscopy is useful to estimate the depth of the melanin and may help in the diagnosis and classification of melasma, with therapeutic importance.

OBJECTIVES

To evaluate the diagnostic concordance of dermoscopic classification of epidermal or mixed subtypes of melasma and the correlation between dermoscopic and histopathological findings.

METHODS

Twenty-eight women with facial melasma, phototypes III to V, ages between 30 and 61 years were selected. Based on the evaluation of clinical and dermoscopic images, two independent observers classified melasma into epidermal or mixed subtypes. The intra and interobserver concordances were calculated. Histopathological analysis of epidermal melanin extension and maximum number of melanophages per high-power field (400×; HPF) have been assessed. Association between the melanophages count and the dermoscopic classification was evaluated.

RESULTS

Intraobserver agreement was 82.1%, and between observers, from 78.6% to 89.3%, according to the Kappa index. Histopathology revealed increased intraepidermal melanin and the presence of dermal melanophages in all the samples. Ten or more melanophages/HPF was significantly associated with mixed melasma.

CONCLUSIONS

Moderate to substantial concordance in the dermoscopic classification of melasma was found, and the correlation between this classification and the dermal melanophages count have been suggested. Intradermal component of every case of melasma should be considered for therapeutic and prognostic purposes.

Evaluation of ex vivo melanogenic response to UVB, UVA, and visible light in facial melasma and unaffected adjacent skin

BACKGROUND

The independent role of solar radiation in the differential melanogenesis between melasma and adjacent skin is unknown.

OBJECTIVES

To assess the melanogenic responses of skin with facial melasma and of the adjacent skin to UVB, UVA, and visible light, in an ex vivo model.

METHODS

This was a quasi-experimental study involving 22 patients with melasma. Facial melasma and adjacent skin samples were collected and stored in DMEM medium, at room temperature. One fragment was placed under the protection from light, while another was exposed to UVB, UVA, and visible light (blue-violet component): 166 mJ/cm2, 1.524 J/cm2, and 40 J/cm2, respectively. Subsequently, all samples were kept for 72 hours in a dark environment and stained by Fontana-Masson to assess basal layer pigmentation, dendrites, and melanin granulation.

RESULTS

Effective melanogenesis was observed in the basal layer in melasma and in the normal adjacent skin after all irradiations (p < 0.01), with the following median increment: UVB (4.7% vs. 8.5%), UVA (9.5% vs. 9.9%), and visible light (6.8% vs. 11.7%), with no significant difference between anatomical sites. An increase in melanin granulation (coarser melanosomes) was observed only after irradiation with UVA and only in the skin with melasma (p = 0.05). An increase in the melanocyte dendrite count induced by UVB radiation was observed in both anatomical sites (p ≤ 0.05).

STUDY LIMITATIONS

Use of an ex vivo model, with independent irradiation regimes for UVB, UVA, and visible light.

CONCLUSIONS

Melanogenesis induced by UVB, UVA, and visible light was observed both in melasma and in the adjacent skin. The morphological patterns suggest that different irradiations promote individualized responses on the skin with melasma.

African ancestry is associated with facial melasma in women: a cross-sectional study

Background

Melasma is a chronic acquired focal hypermelanosis affecting photoexposed areas, especially for women during fertile age. Several factors contribute to its development: sun exposure, sex steroids, medicines, and family history. Melanic pigmentation pathway discloses several SNPs in different populations. Here, we evaluated the association between genetic ancestry and facial melasma.

Methods

A cross-sectional study involving women with melasma and an age-matched control group from outpatients at FMB-Unesp, Botucatu-SP, Brazil was performed. DNA was extracted from oral mucosa swabs and ancestry determined by studying 61 INDELs. The genetic ancestry components were adjusted by other known risk factors by multiple logistic regression.

Results

We evaluated 119 women with facial melasma and 119 controls. Mean age was 39 ± 9 years. Mean age at beginning of disease was 27 ± 8 years. Pregnancy (40%), sun exposure (37%), and hormonal oral contraception (22%) were the most frequently reported melasma triggers. All subjects presented admixed ancestry, African and European genetic contributions were significantly different between cases and controls (respectively 10% vs 6%; 77% vs 82%; p < 0.05). African ancestry (OR = 1.04; 95% CI 1.01 to 1.07), first generation family history (OR = 3.04; 95% CI 1.56 to 5.94), low education level (OR = 4.04; 95% CI 1.56 to 5.94), and use of antidepressants by individuals with affected family members (OR = 6.15; 95% CI 1.13 to 33.37) were associated with melasma, independently of other known risk factors.

Conclusions

Facial melasma was independently associated with African ancestry in a highly admixed population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-017-0378-7) contains supplementary material, which is available to authorized users.

Gene and protein expression of oestrogen-β and progesterone receptors in facial melasma and adjacent healthy skin in women

OBJECTIVE

Compare gene and protein expression for oestrogen receptor-β (ER-β) and progesterone receptor (PR) in facial melasma and adjacent healthy skin.

METHODS

A cross-sectional study including 42 women with facial melasma, conducted at the Dermatology Service of Botucatu Medical School of São Paulo State University, Brazil. Biopsies of the melasma skin were performed, together with healthy surrounding skin. The gene expression (real-time PCR) of the hormone receptors in the tissue was evaluated. Subsequently, skin fragments were immunostained for nuclear ER-β and PR, evaluated according to their HSCORE (epidermis) and percentage of staining per microscopic field (dermis).

RESULTS

Messenger RNA tissue expression for ER-β and PR showed no difference between melasma-affected skin fragments and the healthy perilesional areas (P > 0.2). Median nuclear epithelial expression for ER-β and PR was higher in lesioned skin (HSCORE 157 and 58) than in the healthy perilesional skin (HSCORE 97 and 19; P < 0.01), with no difference in dermal immunostaining. Nuclear histological expression for ER-β was associated to sun-induced melasma and negative familiar background; PR expression was associated to sun-induced melasma and darker phototypes.

CONCLUSION

No difference was observed in gene expression for oestrogen-β and progesterone receptors in melasma-affected skin compared with adjacent healthy skin. However, the higher protein expression of these receptors in melasma-affected epithelia suggests hormonal participation in the pathogenesis of this disease.

Techniques of digital image analysis for histological quantification of melanin

Morphometric analysis of tissue melanin may quantitatively contribute to research on pigmentation disorders. The authors present three methods for image analysis, which allow for identification of melanin-equivalent pixels in the epidermis using Fontana-Masson stain and, therefore, for the calculation of its percentage in the different epidermal layers. Moreover, they discuss the main elements related to the analysis and the need for rigorous standardization of the process.

Morphometric analysis of dermal collagen by color clusters segmentation

Morphometric analysis of dermal collagen can provide quantitative support to dermatologic research. The authors of this article disclose a technique of digital image analysis which allows the identification of microscopic structures by color cluster segmentation regarding the estimate intensity and density of dermal collagen fibers.

[Physiopathology of melasma]

Melasma is a common dermatosis that involves changes in normal skin pigmentation, resulting from the hyperactivity of epidermal melanocytes. The consequent hyperpigmentation is mostly induced by ultraviolet radiation. Clinically, melasma is characterized by light to dark brown macules that usually occur on the face, although they can also affect the cervical and anterior thoracic regions and upper members.Fertile age women and those with intermediate skin phototypes are most likely to develop melasma. Most of its physiopathogenics is not yet fully understood, but there is a relation with genetic and hormonal factors, drugs and cosmetics use, endocrinopathies and sun exposure. The authors discuss the main aspects associated with skin pigmentation and the development of melasma.