Session: Parallel session 10 - Lipidomics, Metabolomics, and Small molecules

Exploring pollutant metabolism in 3D Reconstructed Human Epidermis models using stable labeling and LC/HRMS analysis

Rafael REIS¹, Martine ZANINI², Guillaume LÉREAUX³, Joaquim LIMA¹, Ariane DIMITROV², Laurent MARROT², Natali STOJILJKOVIC¹, Samia BOUDAH¹

¹L'Oréal Recherche & Innovation. Analysis Department, Aulnay sous Bois, France
²L'Oréal Recherche & Innovation. Exposome Discovery Domain, Aulnay sous Bois, France
³L'Oréal Recherche & Innovation. ADME laboratory, Aulnay sous Bois, France

Particulate matter is suspected to be involved in pollution-induced health concerns. In fact, ultrafine particles (UFPs) contain polycyclic aromatic hydrocarbons (PAHs) that can be mutagenic, cytotoxic and phototoxic. Since UFPs reach blood circulation from lung alveoli, skin is very likely contaminated by PAHs coming from either the skin surface or blood. Skin layers may thus be impacted by stress induced by pollution. Hence, understanding the metabolic fate of environmental pollutants in skin is crucial for assessing their potential health risks. Moreover, traditional in vitro models often lack metabolic competency, while animal testing faces ethical concerns.

This study employs a novel approach combining stable isotope labeling and liquid chromatography-high resolution mass spectrometry (LC-HRMS) to investigate the metabolism of benzo[a]pyrene (BaP), an ubiquitous PAH, in 3D reconstructed human epidermis (RHE) models, a physiologically relevant platform to study xenobiotic metabolism in human skin.

RHE models from 3 donors were exposed to BaP for 72 hours, with parallel cultures receiving deuterium-labeled BaP (BaP-d12). Following extraction, samples were analyzed using LC-HRMS. Data analysis incorporating stable isotope filtering, revealed five distinct BaP phase I metabolites, including mono-hydroxylated, dihydroxylated and quinone derivatives. Confirmation of 3-OH BaP occurrence was achieved through standard analysis.

This study demonstrates the power of coupling stable isotope labeling with LC-HRMS for the comprehensive characterization of BaP metabolic pathways in human skin. The identification of specific metabolites enhances our understanding of BaP detoxification mechanisms and potential for adverse effects. This analytical approach holds promise for investigating the metabolic fate of various environmental pollutants in human skin and advancing our understanding of the exposome's impact on skin health.