Gastrointestinal barrier integrity (GBI)

Gastrointestinal barrier integrity describes the physiological state and functional capacity of the intestinal mucosa to serve as a selective semi-permeable barrier. This system is primarily maintained by a physical layer of intestinal epithelial cells (IECs) interconnected by apical junctional complexes, including tight junctions (TJs), adherens junctions, and desmosomes, as well as an overlying chemical layer of mucus [6, 11, 20]. Its biological function is to permit the absorption of essential nutrients and water while simultaneously preventing the translocation of harmful luminal contents, such as pathogens, endotoxins, and antigens, into the systemic circulation [15, 18, 21]. Disruption of this barrier, often referred to as 'leaky gut' or increased intestinal permeability, is implicated in the pathogenesis of various gastrointestinal and systemic disorders, including inflammatory bowel disease (IBD), celiac disease, irritable bowel syndrome (IBS), and sepsis [1, 4, 13, 23]. Therapeutic strategies to restore integrity focus on modulating tight junction proteins like claudins and occludin, often through the use of specific peptides such as larazotide or growth-promoting agents like glucagon-like peptide-2 (GLP-2) analogs [3, 4, 13]. Monitoring the status of the gastrointestinal barrier typically involves non-invasive biomarkers like zonulin, fecal calprotectin, or functional sugar absorption tests to assess paracellular and transcellular permeability [2, 8, 10].

Other names

Intestinal barrier functionGut barrier integrityMucosal barrier integrityIntestinal permeabilityLeaky gut

Regulation of tight junction protein (e.g., zonulin) assembly and stabilization [3, 4, 5], antagonism of zonulin-induced junctional opening [7], inhibition of myosin light chain kinase (MLCK) activity [4, 9], and promotion of mucosal healing and epithelial cell proliferation [9, 13, 20].