Estudo comparativo ultraestrutural de pele antes e após tratamento com tretinoína
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2020-05-18
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A pele é um órgão que reveste toda a superfície do corpo e a separa do mundo exterior, renovando-se constantemente, e tendo como função principal a proteção do corpo contra agressões ambientais. O processo de envelhecimento da pele é um fenómeno biológico, que envolve a ocorrência simultânea de dois processos: envelhecimento intrínseco e extrínseco. O envelhecimento extrínseco, mais propriamente o fotoenvelhecimento, é o mais agressivo. Os retinóides, particularmente a tretinoína tópica, são utilizados para reverter o fotoenvelhecimento da pele. O objetivo deste estudo consistiu na análise ultraestrutural da pele antes e após o uso de tretinoína tópica, de forma a verificar se existem alterações a nível dos sinais de envelhecimento cutâneo. Para este estudo foi utilizada tretinoína em creme a 0,05%, ao nível da face. Participaram indivíduos de ambos os sexos, com idades entre os 56 e os 92 anos. O estudo foi aprovado pelas Comissões de Ética da UTAD e do CHTMAD, tendo os doentes assinado formulários de consentimento informado para a participação. A amostra da primeira colheita foi obtida por biópsia incisional e a amostra da segunda colheita por punch, tendo o material sido processado para Microscopia Eletrónica de Transmissão. Dos oito participantes iniciais apenas cinco concluíram o estudo. Foram evidenciados sinais de envelhecimento cutâneo em ambas as colheitas para cada participante, com graus de envelhecimento diferentes de indivíduo para indivíduo. Dos casos estudados, apenas dois casos apresentaram reação à tretinoína. Num dos casos verificou-se uma alteração a nível da distribuição e estádios de maturação dos melanossomas II-III para III-IV. Noutro caso verificou-se uma redução na quantidade de células atípicas e vacúolos. Pode-se concluir que a tretinoína conseguiu reverter alguns dos danos do fotoenvelhecimento, apesar de não haver uma regressão total dos mesmos, tendo a pele de cada indivíduo reagido de forma e intensidade diferentes. Apesar do benefício comprovado deste composto, existem ainda muitas questões por esclarecer, principalmente relativas aos aspetos ultraestruturais.
The skin is an organ that covers the entire surface of the body and separates it from the outside world, constantly renewing itself, being its main function to protect the body against environmental aggressions. Skin aging is a biological phenomenon involving the simultaneous occurrence of two processes: intrinsic and extrinsic aging. Extrinsic aging, more specifically photoaging, is the most aggressive type. Retinoids, particularly topical tretinoin, are used to reverse skin photoaging. The aim of this study consisted in an ultrastructural skin analysis before and after the use of topical tretinoin in order to check if there were changes in the signs of skin aging. For this study, tretinoin cream 0.05% was used on the face. Patients of both sexes were included, aged between 56 and 92 years. This study was approved by UTAD and CHTMAD Ethics Committees and the patients signed informed consent forms in order to participate. The first sample was obtained by incisional biopsy and the second by punch, being the material processed for Transmission Electron Microscopy. Of the eight initial participants only five completed the study. Skin aging signs were evident in both sample collections for each participant, with different degrees of aging varying from individual to individual. Of the cases studied, only two showed a reaction to tretinoin. In one case, there was a change in the distribution and maturation stages of melanossomes II-III to III-IV. In another case, there was a reduction in the amount of atypical cells and vacuoles. It can be concluded that tretinoin was able to partially reverse photoaging damage, with interindividual differences. Although the beneficial action of this compound has been proven, there are still many unanswered questions, especially regarding the ultrastructural level.
The skin is an organ that covers the entire surface of the body and separates it from the outside world, constantly renewing itself, being its main function to protect the body against environmental aggressions. Skin aging is a biological phenomenon involving the simultaneous occurrence of two processes: intrinsic and extrinsic aging. Extrinsic aging, more specifically photoaging, is the most aggressive type. Retinoids, particularly topical tretinoin, are used to reverse skin photoaging. The aim of this study consisted in an ultrastructural skin analysis before and after the use of topical tretinoin in order to check if there were changes in the signs of skin aging. For this study, tretinoin cream 0.05% was used on the face. Patients of both sexes were included, aged between 56 and 92 years. This study was approved by UTAD and CHTMAD Ethics Committees and the patients signed informed consent forms in order to participate. The first sample was obtained by incisional biopsy and the second by punch, being the material processed for Transmission Electron Microscopy. Of the eight initial participants only five completed the study. Skin aging signs were evident in both sample collections for each participant, with different degrees of aging varying from individual to individual. Of the cases studied, only two showed a reaction to tretinoin. In one case, there was a change in the distribution and maturation stages of melanossomes II-III to III-IV. In another case, there was a reduction in the amount of atypical cells and vacuoles. It can be concluded that tretinoin was able to partially reverse photoaging damage, with interindividual differences. Although the beneficial action of this compound has been proven, there are still many unanswered questions, especially regarding the ultrastructural level.
Descrição
Dissertação de Mestrado em Biologia Clínica Laboratorial
Palavras-chave
Fotoenvelhecimento , Ultraestrutura