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Fate, uptake and impact of fit-for-purpose nanoplastics on the digestive environment: an in vitro-in vivo continuum study
Summary
Researchers used fluorescently and gold-labeled polystyrene nanoplastics as models to study how these particles behave in the digestive environment and what effects they have on gut health. The study revealed that nanoplastics interact with the digestive system in ways that depend on particle labeling and surface properties.
The potential hazards of nanoplastics (NPLs) to human health are poorly known, and interdisciplinary studies are crucial to address such complex issue. The originality of our study lies in the use of different fit-for-purpose labelled (i.e. fluorescent or gold-labelled) polystyrene NPL models. We investigated the impact of NPL exposure on the digestive environment using in vitro and in vivo approaches. Using the standardized in vitro intestinal digestion model INFOGEST 2.0, we studied the interactions between fluorescent NPLs and digestive fluids, simulating the salivary, gastric and intestinal phases. For the salivary phase, adsorption of amylase onto the particles was shown. Moreover, an agglomeration of NPLs during the gastric phase was observed, accompanied by adsorption of pepsin and lipase onto the particle surface, thus potentially influencing their activity and subsequently host's digestion capacities. By using a co-culture of Caco-2/HT29-MTX intestinal cells, we are now evaluating how gastrointestinal digestion affects the fate, uptake and toxicity of NPLs. In parallel, toxicity of gold-labelled NPLs was evaluated on a preclinical in vivo model with an intact intestinal barrier. Gold-core labelling enables to specifically trace NPLs within the whole organism using ICP-MS. Mice were exposed through drinking water to different doses of NPLs (0.1, 1 and 10 mg/kg body weight/day) for 90 days. Interestingly, despite NPLs weren't detected in intestinal tissues and peripherical organs, the main effects were observed at the lowest dose. In particular, NPL exposure modified intestinal gene expression of tight junctions (e.g. JamA, Zo1), pro-inflammatory cytokines (e.g. IL6, TNFa, IL1B) and anti-microbial peptides (e.g. Lysozyme), mucus (e.g. Muc 2). Moreover, some caecal microbial metabolites (including SCFAs, bile salts) were affected by NPL exposure. Based on these first results under physiological conditions, a study is currently carried out under a Western stress diet to mimic at-risk overweight populations (gut barrier defects, dysbiotic gut microbiota). Also see: https://micro2024.sciencesconf.org/558950/document