OCLN and inflammatory bowel disease: Moreover, the expression levels of adhesion and tight junction-related proteins, such as E-cadherin, β-catenin, and occludin, were upregulated in the HF-FVT group and downregulated in the IBD-FVT group (Fig. 5f and Supplementary Fig. 12), indicating improved gut permeability in the HF-FVT group and worsened gut permeability in the IBD-FVT group.