Effects of Enniatin B1 on differentiated Caco-2 human intestinal cells in vitro.

Enniatins (ENNs), naturally occurring contaminants in food and feed, are emerging mycotoxins currently not regulated. The purpose of this study was to evaluate the possible effects of ENN B1 following oral exposure using a human-based intestinal epithelial barrier model. Caco-2 intestinal cells, cultivated on semipermeable filters to obtain the formation of an apical compartment (intestinal lumen) and a basolateral compartment (vascular/lymphatic), were exposed for 24–48 h to apical concentrations of ENN B1 ranging from 0.5 to 6 µM, simulating intestinal mycotoxin exposure. The effects on Trans Epithelial Electrical Resistance (TEER) and interleukin 8 (IL-8) release were evaluated, and a morphological characterization was performed using confocal microscopy and immunofluorescence technique to assess the localization of zona occludens protein 1 and occludin for tight junctions (TJ), and E-cadherin and beta-catenin for adherens junctions (AJ). TEER data showed the absence of adverse effects, even following exposure to higher doses (6 µM) of ENN B1. However, exposure to the mycotoxin for 24 and 48 h caused significant increases in apical secretion of IL-8 as compared to untreated control cells. Moreover, the results obtained from confocal microscopy suggest that exposure to ENN B1, even if it does not alter epithelial permeability, can affect intercellular junctional organization. Further studies are needed to explore these aspects and evaluate the in vitro bioavailability and kinetics of ENN B1 using human-based barrier models.