In Situ Metabolism of Cinnamyl Alcohol in Reconstructed Human Epidermis: New Insights into the Activation of This Fragrance Skin Sensitizer.

Chemical modification of epidermal proteins by skin sensitizers is the molecular event which initiates the induction of contact allergy. However, not all chemical skin allergens react directly as haptens with epidermal proteins but need either a chemical (prehaptens) or metabolic (prohaptens) activation step to become reactive. Cinnamyl alcohol has been considered a model prohapten, as this skin sensitizer has no intrinsic reactivity.

In situ chemical behaviour of methylisothiazolinone (MI) and methylchloroisothiazolinone (MCI) in reconstructed human epidermis: a new approach to the cross-reactivity issue.

Background: Methylisothiazolinone (MI) [with methylchloroisothiazolinone (MCI) in a ratio of 1:3, a well-recognized allergenic preservative] was released as an individual preservative in the 2000s for industrial products and in 2005 for cosmetics. The high level of exposure to MI since then has provoked an epidemic of contact allergy to MI, and an increase in MI/MCI allergy. There are questions concerning the MI/MCI cross-reaction pattern.

Matrix Effect of Human Reconstructed Epidermis on the Chemoselectivity of a Skin Sensitizing α-Methylene-γ-Butyrolactone: Consequences for the Development of in Chemico Alternative Methods.

Adoption of new legislations and social pressure are pushing toward the development of alternative methods to the use of animals for the assessment of most toxicological end-points including skin sensitization. To that respect, much efforts have been put in the first step of the adverse outcome pathway focusing on chemical interactions taking place between sensitizing chemicals or haptens and epidermal proteins. However, these in chemico approaches have been so far only based on the use of model nucleophiles, amino acids, peptides, or proteins in water/buffer solution and focused mainly on thiol reactivity.

HR-MAS NMR spectroscopy of reconstructed human epidermis: potential for the in situ investigation of the chemical interactions between skin allergens and nucleophilic amino acids.

High-resolution magic angle spinning (HR-MAS) is a nuclear magnetic resonance (NMR) technique that enables the characterization of metabolic phenotypes/metabolite profiles of cells, tissues, and organs, under both normal and pathological conditions, without resorting to time-consuming extraction techniques. In this article, we explore a new domain of application of HR-MAS, namely, reconstructed human epidermis (RHE) and the in situ observation of chemical interactions between skin sensitizers and nucleophilic amino acids. First, the preparation, storage, and analysis of RHE were optimized, and this work demonstrated that HR-MAS NMR was well adapted for investigating RHE with spectra of good quality allowing qualitative as well as quantitative studies of metabolites.