Combined Effects of Ethanol and Linoleic Acid on Paracellular Permeability in Caco‐2 Intestinal Epithelial Model

Ethanol‐induced endotoxemia due to disruption of intestinal integrity plays an important role in the alcoholic liver disease. Linoleic acid, a major unsaturated fatty acid in the American diet, exhibits proinflammatory effects in different cell types, however, its effects on intestinal epithelial cells, particularly on paracellular permeability, in combination with ethanol have not been investigated. Materials and Methods Fully differentiated Caco‐2 cells (human colonic carcinoma cell line) were treated with ethanol (EtOH) and linoleic acid (LA). Paracellular permeability (PP) was measured using transepithelial electrical resistance (TEER) measurements as well as passage of FITC‐dextran (FD) in culture inserts. Results Compared to control, EtOH and LA treatments alone decreased TEER in a dose‐ dependent manner, which correlated with increased permeability for FD. Combined exposure of EtOH and LA further enhanced PP disruption. Specifically, treatment of Caco‐2 cells with 100 uM of LA in the presence of 25, 50, and 100 mM of EtOH resulted in a TEER reduction of 20%, 31%, 42% and increase in FD permeability of 1.2, 1.3, 1.4 fold, respectively. Conclusion Combined exposure of EtOH and LA exacerbates disruption of intestinal barrier function, potentially leading to increased endotoxemia and consequent liver injury. This work was supported by funding from NIH and VA.