ReFerm® a Fermented Oat Gruel Composition, Improves Colonic Barrier Function and Modulates Tricellulin Expression in Patients With Irritable Bowel Syndrome.

BACKGROUND: Intestinal barrier dysfunction has been implicated in the pathophysiology of irritable bowel syndrome (IBS), contributing to increased permeability, low-grade inflammation, and symptom generation. Microbial compositions are known to improve epithelial barrier function, although the underlying molecular mechanisms remain elusive. The aim was to investigate the effects of the fermented oat gruel preparation ReFerm® on colonic barrier function and tight junction protein expressions in patients with IBS.

METHODS: Colonic biopsies from patients with IBS were mounted in Ussing chambers to assess the direct effects of ReFerm® on epithelial permeability. In parallel, biopsies from patients treated with ReFerm® or placebo by enema were analyzed for the expression of multiple tight junction proteins using Western blotting and confocal microscopy. In vitro effects were further evaluated in Caco-2 cells.

KEY RESULTS: ReFerm® reduced both paracellular and transcellular permeability when added directly to biopsies mounted in Ussing chambers, compared with unstimulated biopsies. This effect was accompanied by increased expression of the tight junction protein tricellulin at tricellular junctions. In vitro experiments in Caco-2 cells supported these findings, demonstrating direct effects of ReFerm® on epithelial barrier properties.

CONCLUSIONS AND INTERFERENCES: ReFerm® strengthens colonic barrier integrity in the gut mucosa of patients with IBS, potentially through modulation of the tight junction protein tricellulin. These findings provide mechanistic insight into the barrier-protective effects of fermented oat interventions such as ReFerm® and support the potential therapeutic role in IBS.