β(2→1) chicory and β(2→1)-β(2→6) agave fructans protect the human intestinal barrier function in vitro in a stressor-dependent fashion

Abstract

Dietary fibers such as fructans can protect the intestinal epithelial barrier integrity, but the mechanisms underlying this protection are not completely understood. We aimed to study the protective effect of β(2→1)-β(2→6) branched graminan-type fructans (GTFs) on gut epithelial barrier function that was disrupted by three different agents which impact the barrier function via different cellular mechanisms. The effects of GTFs were compared with those of linear β(2→1) inulin-type fructans (ITFs). T84 intestinal epithelial monolayers were incubated with GTFs and ITFs. Afterwards, the monolayers were challenged with the barrier disruptors calcium ionophore A23187, 12-myristate 13-acetate (PMA) and deoxynivalenol (DON). Transepithelial resistance was measured with an electric cell–substrate impedance sensing system. All fructans studied prevented the barrier disruption induced by A23187. ITF II protected from the disruptive effects of PMA. However, none of the studied fructans influenced the disruption induced by DON. As a measure of disruption-induced inflammation, interleukin-8 (IL-8) production by the intestinal epithelium was determined by ELISA. The production of IL-8 induced by A23187 was decreased by all fructans, whereas IL-8 production induced by DON decreased only upon pre-treatment with ITF II. None of the studied fructans prevented PMA induced IL-8 production. GTFs just like ITFs can influence the barrier function and inflammatory processes in gut epithelial cells in a structure-dependent fashion. These distinct protective effects are dependent on the different signaling pathways that lead to gut barrier disruption.