Expression of Endothelin-1, Endothelin Receptor-A, and Endothelin Receptor-B in facial melasma compared to adjacent skin.

Background/Objectives: Although melasma is highly prevalent, its pathogenesis is not yet fully understood. In the skin, endothelin-1 (ET-1) is primarily produced by keratinocytes in response to UVB exposure, which is mediated by an increase in IL-1α or reactive oxygen species. ET-1 plays a role in melanogenesis by binding to specific receptor B (ERB) or receptor A (ERA). However, the expression of ET-1, ERA, and ERB in melasma has not been systematically investigated. The objective of this study was to evaluate the expression of ET-1, ERA, and ERB in facial melasma compared to the adjacent unaffected skin. Methods: Cross-sectional study, with 40 skin samples (20: facial melasma; 20: adjacent unaffected skin) from women with facial melasma without treatment for 30 days except for sunscreen. A triple staining immunofluorescence technique was performed for anti-vimentin, DAPI, plus one of the following antibodies: (a) anti-ET1, (b) anti-ERA; (c) anti-ERB. Interfollicular areas on the slides of each topography (melasma; unaffected skin) were photographed in triplicate under confocal laser microscopy. The mean staining intensities of the image histograms (0-255 pixels intensity) were estimated for different types of cells (suprabasal keratinocytes, basal layer, and upper dermis) and were blindly compared between topographies. Results: The mean (SD) age of the participants was 44.9 (9.2). The expression of ET-1 was increased in the whole epidermis with melasma when compared to the adjacent skin, being 32.8% (CI95% 14.7%-52.6%) higher in the spinous layer (p=0.013), 30.4% (CI95% 13.7%-47.9%) higher in the basal layer (p=0.014), and 29.7% (CI95% 11.4%-49.7%) higher in the melanocytes (p=0.006). There was no noticeable expression of ET-1 within the cells on the upper dermis. Neither ERA nor ERB resulted in differential epidermal expression between melasma and unaffected skin (p≥0.1). Conclusion: ET-1 is expressed more intensely on the epidermis from the skin with facial melasma compared to the unaffected adjacent skin.

Fibroblast morphology, growth rate and gene expression in facial melasma

Abstract Background: In addition to melanocytic hyperfunction, changes are observed in the upper dermis of melasma, and fibroblasts play a central role in collagen synthesis and pigmentation induction. Objective: To explore the morphology, growth rate, and gene expression profile of fibroblasts from the skin with melasma in comparison to fibroblasts from the adjacent healthy skin. Methods: Ten women with facial melasma were biopsied (lesion and adjacent healthy skin), and the fragments were processed for fibroblast culture. Samples from five participants were seeded to evaluate growth (days 2, 5 and 8) and senescence (SA-β-gal) curves. The samples from the other participants were submitted to real-time PCR to comparatively evaluation of the expression of 39 genes. Results: Cultured fibroblasts from melasma skin were morphologically less fusiform in appearance and on average a 34% (95% CI 4%-63%) greater proportion of cells labeled with SA-β-gal than the fibroblasts from the adjacent skin. The cell growth rate was lower for the melasma samples after eight days (p < 0.01). The WNT3A, EDN3, ESR2, PTG2, MMP1, and SOD2 genes were up-regulated, whereas the COL4A1, CSF2, DKK3, COL7A1, TIMP4, CCL2, and CDH11 genes were down-regulated in melasma skin fibroblasts when compared to the ones from adjacent healthy skin. Study limitations: Small sample size; absence of functional tests. Conclusions: Fibroblasts from the skin with melasma showed a lower growth rate, less fusiform morphology and greater accumulation of SA-β-gal than those from adjacent photo exposed skin. Moreover, their gene expression profile comprised factors that may contribute to upper dermis damage and sustained melanogenesis.

Fibroblast morphology, growth rate and gene expression in facial melasma.

BACKGROUND: In addition to melanocytic hyperfunction, changes are observed in the upper dermis of melasma, and fibroblasts play a central role in collagen synthesis and pigmentation induction. OBJECTIVE: To explore the morphology, growth rate, and gene expression profile of fibroblasts from the skin with melasma in comparison to fibroblasts from the adjacent healthy skin. METHODS: Ten women with facial melasma were biopsied (lesion and adjacent healthy skin), and the fragments were processed for fibroblast culture. Samples from five participants were seeded to evaluate growth (days 2, 5 and 8) and senescence (SA-ß-gal) curves. The samples from the other participants were submitted to real-time PCR to comparatively evaluation of the expression of 39 genes. RESULTS: Cultured fibroblasts from melasma skin were morphologically less fusiform in appearance and on average a 34% (95% CI 4%‒63%) greater proportion of cells labeled with SA-ß-gal than the fibroblasts from the adjacent skin. The cell growth rate was lower for the melasma samples after eight days (p < 0.01). TheWNT3A, EDN3, ESR2, PTG2, MMP1, and SOD2 genes were up-regulated, whereas the COL4A1, CSF2, DKK3, COL7A1, TIMP4, CCL2, and CDH11 genes were down-regulated in melasma skin fibroblasts when compared to the ones from adjacent healthy skin. STUDY LIMITATIONS: Small sample size; absence of functional tests. CONCLUSIONS: Fibroblasts from the skin with melasma showed a lower growth rate, less fusiform morphology and greater accumulation of SA-ß-gal than those from adjacent photo exposed skin. Moreover, their gene expression profile comprised factors that may contribute to upper dermis damage and sustained melanogenesis.

Histological changes in facial melasma after treatment with triple combination cream with or without oral tranexamic acid and/or microneedling: A randomised clinical trial.

Background Melasma is an acquired dyschromia with several histologic alterations in the epidermis, basement membrane and upper dermis. The treatment of melasma is challenging due to the irregular response and chronicity of the disease. To date, there are no curative strategies, largely due to the limited understanding of the intrinsic effects of each treatment. Objectives The objective of the study was to evaluate the histological changes promoted by triple combination cream, with or without complementary treatment with microneedling and oral tranexamic acid, in the treatment of melasma. Methods A factorial, randomised, controlled and evaluator-blinded clinical trial was performed involving 64 women with facial melasma, divided in four groups, who underwent 60 days of treatment with triple combination cream alone (control group) or combined with two monthly microneedling sessions (microneedling group), TA 250 mg twice daily (tranexamic acid group), or both tranexamic acid group and microneedling group. The participants underwent biopsy of the area with melasma at inclusion (D1) and D60. The primary outcomes were the variation (D1 × D60) between the variables: Thickness of the epidermis and stratum corneum, stratum corneum compaction and solar elastosis; melanin density in the epidermis and upper dermis; proportion between the extension of the nonintact and intact basement membrane zone; mast cell count in the upper dermis; melanocyte count in the basal layer, pendulum melanocyte count and melanocyte area; immunostaining density of vascular endothelial growth factor; stem cell factor and keratinocyte growth factor. Results One participant in the TG discontinued tranexamic acid due persistent headache; and herpes simplex occurred in three patients after microneedling. The groups showed a 24% (CI95%: 17-35%; P < 0.01) reduction in epidermal melanin density. There was no change in dermal melanin density or the area of melanocytes after treatment. There was an overall 25% (CI95%: 7-42%; P < 0.01) reduction in the number of pendulum melanocytes, especially in the microneedling and tranexamic acid group, that presented a 41% (CI95%: 7-73%; P < 0.01) reduction. The extension of the nonintact basal membrane relative to the intact basal membrane decreased after treatment, especially in microneedling group and microneedling and tranexamic acid group. There was an increase of 13% (CI95%: 5-21%; P = 0.02) in epidermal thickness and 6% (CI95%: 0-22%; P = 0.04) thinning of the stratum corneum in the groups. All groups showed stratum corneum compaction. Solar elastosis improved only in the microneedling group and microneedling and tranexamic acid group. Vascular endothelial growth factor immunostaining increased 14% (CI95%: 4-24%; P = 0.03) in the groups; and stem cell factor increased only in microneedling group. There was no change in the number of mast cells, CD34 and keratinocyte growth factor immunostaining. Limitations The site of biopsy may not represent all of the facial melasma and the immunohistochemical sensitivity of the cytokines does not have a stoichiometric relationship with proteins. Conclusion A greater thickness of the epidermis is associated with melasma bleaching. Dermal melanin seems to have no impact on melasma prognosis. Damage to the skin barrier and stimulus of angiogenesis should be avoided in the treatment of melasma. Microneedling complements the topical treatment of melasma by improving patterns of skin photoaging. Oral tranexamic acid complements the topical treatment of melasma by inhibiting the stem cell factor.

Estudo piloto sobre a eficácia e segurança do uso da cisteamina 5% como terapia de contato por toda noite no tratamento do melasma facial / Efficacy and safety of the 5% cysteamine cream left in overnight for facial melasma: a pilot study

Não se aplica, trata-se de uma carta

Not applicable, this is a letter.

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.