MICROBIOME AND GUT EPITHELIAL BARRIER

The human gastrointestinal tract functions as both a digestive system and a highly complex immuno-logical and microbial ecosystem. Central to this dynamic is the gut microbiome, comprising trillions of microorganisms that shape host metabolism, epithelial integrity, and immune regulation. The gut epi-thelial barrier, composed of specialized cells, tight junctions (TJ), and mucus layers, acts as a selective filter, allowing nutrient absorption while blocking pathogens and harmful antigens. The bidirectional interaction between microbiota, epithelial structures, and the immune system is crucial for maintaining tolerance to dietary and environmental antigens; disruption of this balance is increasingly linked to allergic, metabolic, and autoimmune diseases.