The dermal stem cell factor and c-kit are overexpressed in melasma

Abstract

SummaryBackground The pathogenesis of melasma has not yet been clearly demonstrated. We tried to determine whether the stem cell factor (SCF) and its receptor c-kit are involved in the mechanism of hyperpigmentation of melasma because this factor is highly implicated in the stimulation of melanocyte function in vitro and in vivo. Objectives The present study was conducted to investigate the expression of SCF and c-kit on the lesions of melasma compared with nonlesional skin. Patients/methods Skin samples were obtained from lesional and nonlesional facial skin of 60 Korean women with melasma. Immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed to determine the expression of SCF and c-kit in melasma. Results The expression of SCF was significantly increased at the lesional dermis compared with nonlesional dermis. However, there was no significant difference in the expression of SCF in lesional and nonlesional epidermis. The expression of c-kit was significantly increased at lesional epidermis compared with nonlesional skin. RT-PCR of SCF and c-kit mRNAs demonstrated increased expression of both types of transcripts in the lesional skin compared with nonlesional skin. Conclusions These results suggest that the increased expression of SCF in the dermis and of c-kit in the epidermis play an important role in the mechanism of hyperpigmentation in melasma.

Fisiopatologia do melasma

“…Também é conhecida a regulação por oncogene-a relacionado ao crescimento, para interações entre melanócitos e ceratinócitos, fator de crescimento hepatocítico e fator stem cell,l tipo solúvel, para interações entre fibroblastos e melanócitos. 1,79,80 Esta inter-relação também envolve alguns receptores específicos expressos nos melanócitos, como: o receptor de endotelina B, o receptor de fator stem cell e c-KIT. A up ou downregulation, dessa rede interligada, está intrinsecamente envolvida na estimulação das funções melanocíticas, em várias desordens epidérmicas que cursam com alterações na pigmentação.…”

“…A up ou downregulation, dessa rede interligada, está intrinsecamente envolvida na estimulação das funções melanocíticas, em várias desordens epidérmicas que cursam com alterações na pigmentação. 79,80 Achados imunohistoquímicos sugerem que uma forte imunorreatividade de α-MSH na pele lesada de melasma é um dos maiores fatores na gênese dessa doença. A relação entre área fotoexposta e a maior imunorreatividade de α-MSH na pele lesada ainda não foi elucidada.…”

“…79,92 Perfis de citocinas melanogênicas são expressas nas peles lesada e sã, assim como as células de origem, as decorrências locais e os estímulos desencadeantes permitiriam uma compreensão dos elementos, envolvidos na gênese do melasma. 79,80,93,94 Enfim, estudos epidemiológicos de base populacional ou de subgrupos de pacientes com melasma, como gestantes, mulheres pós-menopausa ou homens também contribuiriam para a elaboração de novas hipóteses sobre a história natural e fisiopatogê-nese da doença.…”

The vascular characteristics of melasma

“…Very recently, we suggested that dermal inflammation induced by accumulation of UV irradiation may be associated with activation of fibroblasts, which result in the up-regulation of stem cell factor in melasma dermal skin leading to increased melanogenesis [3]. These studies have given us new insights on the pathogenesis of melasma, in particular, that the dermal environment may have an important role in the development of melasma.…”

Improvement of Lentigines by Oral Crocetin Administration and Examination of Its Mechanism of Action

“…Stressful stimuli, such as UV rays and inflammation, can cause melanocytes to become easily influenced by Stem Cell Factor (SCF), a cytokine, and Melanocyte-Stimulating Hormone (MSH), the hormone that promotes melanin synthesis. Melanocytes are activated by receiving these factors through various signal transduction systems that take place within the melanocytes [7,8]. It has been reported that there are individual differences in susceptibility to the appearance of lentigines on the skin, and Melanocortin Receptor Subtype 1 (MC1R) varies in people with melasma and freckles.…”