Samara Eberlin, Gustavo Facchini, Michelle Sabrina da Silva, Gustavo Henrique da Silva, Ana Lúcia Tabarini Alves Pinheiro, Adilson Costa.
Atopic dermatitis (AD) is a chronically relapsing inflammatory disease associated with genetic predisposition and environmental factors. Altered immune response and skin barrier dysfunction are the mainly responsible for skin lesion onset characterized by severe itching. Affected patients are highly sensitized to house dust mite, such as Dermatophagoides farinae (DF), which is considered a common environmental allergen causing AD. Among the abnormalities in epidermal barrier, changes in lipid profile of stratum corneum are highlighted, and the most notable feature is the decrease in ceramide levels. In addition, there is a reduction in the levels of envelope proteins filaggrin, involucrin and loricrin. Ex vivo AD model was developed using skin fragments obtained from elective plastic surgery and submitted to epidermal barrier disruption with 4% sodium lauryl sulfate. Complementary, skin was exposed to DF extract for two consecutive days. Skin fragments were collected, fixed and cryopreserved for immunofluorescence evaluation of filaggrin, involucrin, loricrin and sphingomyelin synthase. Our results revealed that human experimental AD model was able to satisfactorily mimic skin characteristics of AD by significantly reducing the filaggrin, involucrin and loricrin labeling when compared to control group. Labeling for sphingomyelin synthase - which is directly related to ceramide synthesis, also dropped considerably. Fragments of ex vivo human skin constitute the experimental model that most closely approximates the real conditions to evaluate the efficacy and safety of products applied topically. These findings strongly suggest that this model can be useful not only for elucidating DA pathogenesis but also for the evaluating novel therapeutic agents.