TJP1 and metabolic dysfunction-associated steatotic liver disease: Another study investigated small intestinal bacterial overgrowth (by glucose hydrogen breath test), gut permeability (by urinary excretion of (51)Cr-ethylene diamine tetraacetate ((51)Cr-EDTA), and immunohistochemical analysis of zona occludens-1 (ZO-1) expression in duodenal biopsy specimens as a marker of the integrity of TJs in patients with biopsy-proven NAFLD (n = 35), patients with untreated celiac disease (n = 27) and healthy subjects (n = 24).