SENS-IS®, an EpiskinTM Based Model for Identifying Chemical Sensitizers - Evaluation of SENS-IS®, an Episkin® based model for Identifying Chemical Sensitizers

In the context of the 2013 ban given by EU Cosmetics Directive, the ability to identify and classify the skin sensitization potential of chemicals without animals is of high importance for the cosmetic industry. A range of different in vitro chemistry-based (DPRA, GSH reactivity) and cell-based methods (MUSST, hCLAT, Keratinosens) have been developed and we are currently evaluating some of them for their applicability to cosmetic ingredients and their physico-chemical diversity. Although these assays appear to be promising for hazard identification, potency assessment is still limited.

Immunosearch has developed SENS-IS, a new method, based on the quantitative analysis of specific biomarkers expressed in 3D reconstructed epidermis (Episkin®). This new assay provides a possible way to encompass the limitations of monolayer culture models (lack of skin bioavailability properties, different metabolism of the models compared to skin, inability to test water insoluble chemicals) and might therefore allow a better assessment of the sensitization potency of cosmetic ingredients. With the aim to evaluate the predictive capacity of this approach on a panel of cosmetic ingredients, L’Oréal provided a set of 40 proprietary and public domain chemicals that were assessed by Immunosearch in a blinded manner. The results of this study show an overall performance of sensitizer/non sensitizer prediction of 87 % with a specificity of 83 % and a sensitivity of 91 %. The predictive capacity of potency categories of sensitizers (strong, moderate, weak) is however less performant (63% concordance) with 7 chemicals being overestimated and 8 chemicals being underestimated. Altogether, even if not yet sufficient for potency determination, SENS-IS is a promising new method for the skin sensitization evaluation of cosmetic ingredients.