Estudo comparativo morfofuncional de melanócitos em lesões de melasma
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Data
2007-12-01
Autores
Miot, Luciane Donida Bartoli [UNESP]
Miot, Hélio Amante [UNESP]
Silva, Marcia Guimarães da [UNESP]
Marques, Mariângela Esther Alencar [UNESP]
Título da Revista
ISSN da Revista
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Editor
Sociedade Brasileira de Dermatologia
Resumo
FUNDAMENTOS - Melasma é hipermelanose comum caracterizada por máculas acastanhadas em áreas fotoexpostas, cuja fisiopatogenia não é totalmente esclarecida. OBJETIVOS - Caracterizar e comparar morfologica e funcionalmente os melanócitos da epiderme sã com os da pele afetada por melasma. MÉTODOS - Avaliaram-se 12 pacientes portadores de melasma facial, sendo realizadas biópsias da pele lesada e pele sã adjacente. Os cortes foram corados por hematoxilina-eosina, Fontana-Masson, marcados pelo Melan-A e submetidos à microscopia eletrônica. A quantificação epidérmica de melanina e melanócitos foi estimada a partir de análise citomorfométrica digital. RESULTADOS - Todas as pacientes eram mulheres com média de idade 41,3±2,8 anos. Ao Fontana-Masson evidenciou-se importante aumento da melanina epidérmica na pele lesada em relação à pele sã. A marcação pelo Melan-A demonstrou melanócitos maiores com dendritos proeminentes na pele lesada. Observou-se maior densidade de melanina epidérmica na pele lesada, e a análise digital do número de melanócitos da epiderme não demonstrou diferença significativa entre pele lesada e sã. À microscopia eletrônica, observaram-se número aumentado de melanossomas maduros nos ceratinócitos e melanócitos com organelas citoplasmáticas proeminentes na pele lesada. CONCLUSÕES - Melanogênese aumentada na epiderme com melasma em relação à epiderme normal adjacente.
BACKGROUND - Melasma is a common hypermelanosis characterized by symmetric brownish macules on photoexposed areas, most frequently on the face of women. Its pathophysiology is still unknown. OBJECTIVES - To morphologically and functionally characterize and compare melanocytes of normal skin and of melasma. METHODS - Twelve patients with facial melasma were assessed and biopsies of lesions and adjacent healthy skin were performed. The slices were stained with hematoxylin-eosin and Fontana-Masson, immunohistochemically marked for Melan-A and evaluated by electronic microscopy. Quantification of epidermal melanin and melanocytes was estimated by digital cytomorphometric analysis. RESULTS - All patients were female, mean age of 41.3±2.8 years. The Fontana-Masson staining showed an important increase in epidermal melanin as compared to normal skin. The Melan-A staining demonstrated larger and intensely marked melanocytes and more prominent dendrites in the damaged skin. Greater epidermal melanin density was observed in melasma lesions and the digital analysis of number of epidermal melanocytes did not show a significant difference between damaged and normal skin. Electronic microscopy analysis revealed an increased number of mature melanosomes in keratinocytes and melanocytes, with marked cytoplasmic organelles in melasma skin. CONCLUSIONS - Melanogenesis is increased on melasma epidermis as compared to adjacent normal skin.
BACKGROUND - Melasma is a common hypermelanosis characterized by symmetric brownish macules on photoexposed areas, most frequently on the face of women. Its pathophysiology is still unknown. OBJECTIVES - To morphologically and functionally characterize and compare melanocytes of normal skin and of melasma. METHODS - Twelve patients with facial melasma were assessed and biopsies of lesions and adjacent healthy skin were performed. The slices were stained with hematoxylin-eosin and Fontana-Masson, immunohistochemically marked for Melan-A and evaluated by electronic microscopy. Quantification of epidermal melanin and melanocytes was estimated by digital cytomorphometric analysis. RESULTS - All patients were female, mean age of 41.3±2.8 years. The Fontana-Masson staining showed an important increase in epidermal melanin as compared to normal skin. The Melan-A staining demonstrated larger and intensely marked melanocytes and more prominent dendrites in the damaged skin. Greater epidermal melanin density was observed in melasma lesions and the digital analysis of number of epidermal melanocytes did not show a significant difference between damaged and normal skin. Electronic microscopy analysis revealed an increased number of mature melanosomes in keratinocytes and melanocytes, with marked cytoplasmic organelles in melasma skin. CONCLUSIONS - Melanogenesis is increased on melasma epidermis as compared to adjacent normal skin.
Descrição
Palavras-chave
Imunoistoquímica, Melanócitos, Melanose, Melanossomas, Microscopia eletrônica, Immunohistochemistry, Melanocytes, Melanosis, Melanosomes, Microscopy, electron
Como citar
Anais Brasileiros de Dermatologia. Sociedade Brasileira de Dermatologia, v. 82, n. 6, p. 529-534, 2007.