Host intestinal epithelial barrier (IEB)

The host intestinal epithelial barrier is a critical multi-layered interface that separates the internal milieu of the body from the external environment of the intestinal lumen [1]. It consists of a physical barrier formed by a single layer of epithelial cells and an overlying mucus layer, a chemical barrier of antimicrobial peptides, and an immunological barrier comprising secretory IgA and specialized immune cells [2]. The integrity of this barrier is maintained by apical junctional complexes, primarily tight junctions (composed of claudins, occludin, and zonula occludens proteins), which regulate the paracellular transport of ions and small molecules while excluding larger pathogens and toxins [3]. Dysfunction of the intestinal barrier, often referred to as increased intestinal permeability or leaky gut, is a central feature in the pathogenesis of various inflammatory and autoimmune conditions, including Crohn's disease, ulcerative colitis, and celiac disease [1,4]. Therapeutic interventions targeting the barrier aim to restore its selective permeability by modulating tight junction proteins or promoting mucosal repair and growth [1]. Monitoring barrier integrity in clinical settings often involves biomarkers such as serum zonulin, intestinal fatty acid-binding protein (I-FABP), or functional tests like the lactulose/mannitol ratio [2,3].

Other names

Gut barrierIntestinal mucosal barrierIntestinal epitheliumIntestinal permeability barrier

Modulation of tight junction assembly, stimulation of epithelial cell proliferation, enhancement of mucus secretion, and reduction of pro-inflammatory cytokine-mediated barrier damage.