Exploring pathways for sustained melanogenesis in facial melasma: an immunofluorescence study

Author(s)

Esposito, A. C. C. ^[1] ; Brianezi, G. ^[2] ; de Souza, N. P. ^[2] ; Miot, L. D. B. ^[1] ; Marques, M. E. A. ^[2] ; Miot, H. A. ^[1]

Affiliation

^[1] SN Fac Med, Dept Dermatol & Radioterapia, Ave Prof Mario Rubens Guimaraes Montenegro, BR-18618687 Botucatu, SP - Brazil

^[2] SN Fac Med, Dept Patol, Ave Prof Mario Rubens Guimaraes Montenegro, BR-18618687 Botucatu, SP - Brazil

• Document type: Journal article
• Source: International Journal of Cosmetic Science; v. 40, n. 4, p. 420-424, AUG 2018.
• Web of Science Citations: 2

Abstract

BackgroundThe physiopathology of epidermal hypermelanization in melasma is not completely understood. Several cytokines and growth factors are increased in skin with melasma, nevertheless, nor the pathways involved in the increased MSH expression have been adequately evaluated, nor a model for sustained focal melanogenesis is available. ObjectiveTo explore stimulatory pathways for epidermal pigmentation in facial melasma related to MSH: those linked to ultraviolet radiation, oxidative stress, inflammation, neural crest pigmentation cell differentiation and antagonism of MSH. MethodsPaired skin biopsies (3mm) from 26 women with facial melasma and from normal adjacent skin (<2cm far) were processed for immunofluorescence with markers for p53, p38, MSH, MC1R, Melan-A, IL-1, COX2, Wnt1, WIF-1 and ASIP. ResultsThe fluorescence intensity in the skin from melasma was higher for MC1R, MSH at epidermis as at melanocytes (P<0.05). There were no differences between the sites in epidermal protein expression of COX2, IL-1, p53, WIF-1 and ASIP (P>0.1). P53 was expressed only in epidermis, without difference between sites (P=0.92). WNT1 was remarkable in the epidermis of melasma (P<0.01), but not in dermis. Positive p38 cells were prominent in the upper dermis of melasma (P<0.01), despite no marking in epidermis. ConclusionMelanogenesis in melasma involves epithelial secretion of MSH and activation of the Wnt pathway; nevertheless, it seems to be independent of the stimulation by ultraviolet radiation/p53, IL-1, COX2/PgE(2), WIF-1 and ASIP. Damaged cells at upper dermis suggest the role of senescence/autophagy in sustained pigmentation in melasma. (AU)

• FAPESP's process: 12/05004-1 - Morphofunctional assessment and genomic culture of melanocytes from patients with facial melasma
• Grantee: Gabrielli Brianezi
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 12/09233-5 - Morphofunctional and genomic evaluation of melanocytes culture from patients with facial melasma
• Grantee: Hélio Amante Miot
• Support Opportunities: Regular Research Grants