To Örebro University

OBJECTIVE: Infliximab is important in the therapeutic arsenal of Crohn's disease (CD). However, its effect on mucosal barrier function is not fully understood. Adherent-invasive Escherichia coli (AIEC) are important in CD pathophysiology, but the transmucosal uptake routes are partly unknown. We investigated effects of infliximab on uptake of colon-specific AIEC HM427 across CD colonic mucosa.

MATERIALS AND METHODS: Cr-EDTA) and transmucosal passage of GFP-expressing HM427 were studied. Mechanisms of HM427 transepithelial transport were investigated in Caco-2 monolayers treated with TNF, in the presence of infliximab and/or endocytosis inhibitors.

RESULTS: Cr-EDTA permeability were increased in CD (p < .05), but were restored to control levels by infliximab (CD: 150 (18.8-1069)). In TNF-exposed Caco-2 monolayers HM427 transport and lipid rafts/HM427 co-localization was decreased by infliximab. The lipid raft inhibitor methyl-β-cyclodextrin decreased HM427 transport.

CONCLUSION: Infliximab restored the colonic barrier to AIEC in CD; an effect partially mediated by blocking lipid rafts in epithelial cells. This ability likely contributes to infliximab's clinical efficacy in colonic CD.