The <i>Ex Vivo</i> Skin Model as an Alternative Tool for the Efficacy and Safety Evaluation of Topical Products

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 <i>in vivo</i> 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 <i>ex vivo</i> 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.