Intestinal epithelial barrier and mucus layer (IEB)

The intestinal epithelial barrier and mucus layer represent a critical physiological interface that maintains homeostasis by segregating the systemic circulation from the diverse microbial and antigenic environment of the gut lumen (Vancamelbeke & Vermeire, 2017). This multi-component system includes a biochemical barrier of antimicrobial peptides and a physical barrier consisting of a mucus layer, primarily Mucin-2, and a polarized epithelial cell layer connected by tight junctions, adherens junctions, and desmosomes (Okumura & Takeda, 2017). Its primary biological function is to facilitate the selective absorption of nutrients and water while restricting the translocation of pathogens and pro-inflammatory molecules (Chelakkot et al., 2018). Impairment of this barrier, often referred to as increased intestinal permeability or "leaky gut," is a central feature in the pathogenesis of inflammatory bowel disease (IBD), celiac disease, and certain systemic metabolic conditions (Groschwitz & Hogan, 2009). Therapeutic interventions target this system through various mechanisms, such as the use of GLP-2 analogs like teduglutide to promote mucosal growth or tight junction regulators like larazotide to reduce paracellular permeability. Monitoring the integrity of this barrier often involves measuring biomarkers like serum zonulin, intestinal fatty acid-binding protein (I-FABP), or the lactulose-to-mannitol urinary excretion ratio.

Other names

Gut barrierIntestinal mucosal barrierGastrointestinal barrierMucosal barrierIntestinal permeability barrier

Modulation of tight junction assembly, stimulation of mucin production by goblet cells, and induction of epithelial cell proliferation and survival.