ABSTRACT
The development of alternative approaches for safety and efficacy testing that avoid the use of animals is a worldwide trend, which relies on the improvement of current models and tools so that they better reproduce human biology. Human skin from elective plastic surgery is a promising experimental model to test the effects of topically applied products. As the structure of native skin is maintained, including cell population (keratinocytes, melanocytes, Langerhans cells and fibroblasts) and dermal matrix (containing collagen, elastin, glycosaminoglycans, etc.), it most closely matches the effects of substances on in vivo human skin. In this review, we present a collection of results that our group has generated over the last years, involving the use of human skin and scalp explants, demonstrating the feasibility of this model. The development of a test system with ex vivo skin explants, of standard size and thickness, and cultured at the air-liquid interface, can provide an important tool for understanding the mechanisms involved in several cutaneous disorders.
Subject(s)
Animal Testing Alternatives , Cell Culture Techniques , Skin , Animal Testing Alternatives/methods , Animal Testing Alternatives/standards , Animals , Cell Culture Techniques/standards , Cells, Cultured , Humans , Skin/cytology , Surgery, PlasticABSTRACT
Introdução: A radiação infravermelha A (IV-A) causa alterações estruturais na pele, similares àquelas provocadas pela exposição prolongada à radiação ultravioleta. A avaliação de eficácia e segurança para produtos cosméticos concentra-se em ensaios in vitro e clínicos. Uma alternativa promissora é a utilização de fragmentos de pele humana provenientes de cirurgias plasticas eletivas, para avaliar os reais beneficios os reais benefícios clínicos de um produto aplicado topicamente. Objetivo: O objetivo desta investigação foi correlacionar os efeitos da radiação IV-A, em biópsias e em fragmentos de pele ex vivo e cultura de fibroblastos humanos, pela quantificação dos mediadores MMP-1, TIMP-1 e GADD45a. Métodos: Coleta de biópsias de 15 voluntárias após aplicações de IV-A durante cinco dias consecutivos. Exposição à radiação IV-A de fragmentos de pele humana provenientes de cirurgia plástica eletiva e cultura de fibroblastos humanos. Mensuração dos mediadores MMP-1, TIMP-1 e GADD45a para posterior comparação dos resultados. Resultados: Nos três modelos utilizados a radiação IV-A induziu aumento de MMP-1, inibiu a síntese de GADD45a e não alterou os valores de TIMP-1. Conclusão: Devido à correlação positiva dos modelos estudados, pode-se sugerir o uso de pele ex vivo como ferramenta plausível e sustentável para suprir diferenças entre conhecimentos gerados a partir de experimentos in vitro e clínico.
Introduction: Infrared radiation (IR-A) causes structural changes in the skin, similar to those caused by prolonged exposure to ultraviolet radiation. Evaluation of efficacy and safety of cosmetic products concentrates in in vitro tests and clinical trials. A promising alternative is the use of fragments of human skin from elective cosmetic surgery, to evaluate the actual clinical benefits of a product applied topically. Objective: The objective of this study was to correlate IR-A radiation effects in biopsies and in ex vivo skin fragments and in human fibroblasts culture by quantifying MMP-1, TIMP-1 and GADD45a mediators. Methods: Collection of biopsies from 15 volunteers after IR-A applications for 5 consecutive days. Exposure to IR-A radiation of human skin fragments from elective cosmetic surgery, and human fibroblasts culture. Measurement of MMP-1, TIMP-1 and GADD45a mediators for further comparison of results. Results: In the three models used, the IR-A radiation induced an increase in MMP-1, inhibited the synthesis of GADD45a, and did not changed TIMP-1 values. Conclusion: Due to the positive correlation of the models studied, it may be suggested the use of ex vivo skin as plausible and sustainable tool to overcome differences between knowledge generated from in vitro and clinical experiments.
