Assessing the differential responses in normal and inflamed in vitro intestinal models exposed to food contaminants...

The intestinal barrier is crucial for gut health, and its dysfunction can lead to chronic inflammatory conditions. Food contaminants like pesticides, heavy metals, mycotoxins, heterocyclic aromatic amines (HAAs), and polycyclic aromatic hydrocarbons (PAHs) may worsen these conditions. However, research often overlooks the complex interactions between contaminants and the different cells in the intestine. This study explores the effects of repeated exposure to a mixture of 45 food contaminants on a triculture cell model (Caco-2/HT29-MTX monolayers and THP-1 cells) under normal and inflamed conditions. Two exposure scenarios were tested: a low-level mixture (LOW) reflecting daily diet exposure and a worst-case (WS) scenario. Cytotoxicity, barrier integrity, the expression of inflammation, oxidative stress, and intestinal barrier-related genes, as well as intestinal compounds absorption, were assessed. LOW and WS tested mixtures were confirmed to be non-cytotoxic to the monolayer. The inflamed model was validated with a 23 % reduction in TEER value compared to the normal. The WS mixture caused a maximum TEER decrease of 61 % after repeated exposure. The inflamed model was more vulnerable to contaminants, though the normal also showed significant effects. Gene expression revealed modulation of inflammation and oxidative stress, indicating that even real-life levels of food contaminants exacerbate these responses. The WS mixture induced 6-8 times the expression of inflammatory cytokines IL-8 and IL-1β. No significant differences (p > 0.05) were found in contaminants absorption between the models, but the absorption patterns align with known data. These findings enhance understanding of the intestinal effects of exposure to food contaminant mixtures in the diet.