Fate and impact of nanoplastics in the human digestive environment after oral exposure: A common challenge for toxicology and chemistry

International audienceNanoplastics (NPLs), the presence in the environment of which was considered only “highly plausible” until recently, have become the focus of environmental and ecotoxicological studies. However, up to know, little is known about the potential risks of NPLs to human health. In this review, we provide an overview of the evidence of a specific impact of NPLs on human digestive health reported to date. We focus on the different sources of oral exposure to NPLs, including food packaging, food and beverages. We then summarize the toxicological effects of such exposure on the digestive ecosystem in vitro and in vivo in rodents. Importantly, gut toxicity results should be assessed with the type of NPL model materials employed, due to the critical influence of their chemical and physical properties. As a result, we thoroughly describe NPLs with their source, chemical composition and physicochemical behavior to emphasize the lack of NPL characterization and/or model materials. Finally, we propose avenues for interdisciplinary studies at the interface of toxicology and chemistry, with a view to achieving appropriate scientific assessments of the risks to gut health posed by NPLs, and improvements in their management

Lactococcus lactis CNCM I‐5388 versus NCDO2118 by its GABA hyperproduction ability, counteracts faster stress‐induced intestinal hypersensitivity in rats

International audienceIrritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by its main symptom, visceral hypersensitivity (VH), which is aggravated by stress. Gut–brain interactions and gut bacteria may alleviate IBS symptoms, including VH. γ‐amino butyric acid (GABA), produced notably by lactic acid bacteria (LAB), shows promising result in IBS symptoms treatment. In bacteria, GABA is generated through glutamate decarboxylase (GAD) metabolism of L‐glutamic acid, maintaining intracellular pH. In mammals, GABA acts as an inhibitory neurotransmitter, modulating pain, stress, and anxiety. Therefore, utilizing GABA‐producing LAB as a therapeutic approach might be beneficial. Our previous work showed that a GABA‐producing Lactococcus lactis strain, NCDO2118, reduced VH induced by acute stress in rats after a 10‐day oral treatment. Here, we identified the strain CNCM I‐5388, with a four‐fold higher GABA production rate under the same conditions as NCDO2118. Both strains shared 99.1% identical GAD amino acid sequences and in vitro analyses revealed the same optimal pH for GAD activity; however, CNCM I‐5388 exhibited 17 times higher intracellular GAD activity and increased resistance to acidic pH. Additionally, in vivo experiments have demonstrated that CNCM I‐5388 has faster anti‐VH properties in rats compared with NCDO2118, starting from the fifth day of treatment. Finally, CNCM I‐5388 anti‐VH effects partially persisted after 5‐day treatment interruption and after a single oral treatment. These findings highlight CNCM I‐5388 as a potential therapeutic agent for managing VH in IBS patients

Propriétés antinociceptives chez le rat de Lactococcus lactis CNCM I-5388 hyperproducteur de GABA : vers un nouveau traitement contre l'hypersensibilité viscérale

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