Stool–mucus interface

The stool–mucus interface represents the complex physiological boundary in the large intestine where the fecal stream meets the protective mucus layer covering the intestinal epithelium. This interface is characterized by a gradient of oxygen, nutrients, and microbial density, serving as a critical selective barrier that facilitates nutrient absorption while sequestering the dense gut microbiota away from the host's epithelial cells (Johansson et al., 2011, Nature Reviews Gastroenterology & Hepatology). The primary structural component of this interface is the gel-forming mucin MUC2, which forms a dense, inner stratified layer that is normally devoid of bacteria and a loose outer layer where host-microbe interactions occur (Hansson, 2020, Science Immunology). In pathological states such as ulcerative colitis, the integrity of this interface is compromised, leading to direct contact between fecal bacteria and the epithelium, which triggers chronic inflammation. While the stool–mucus interface is not a single molecular target, it is a major focus in pharmacology and biotechnology for the development of mucus-penetrating or mucoadhesive drug delivery systems designed to optimize the local or systemic delivery of therapeutics (Ensign et al., 2012, Advanced Drug Delivery Reviews).

Other names

Fecal-mucus interfaceIntestinal mucus barrierColonic mucus-stool interfaceMucus-microbiota interface

Not applicable as this is a physiological interface/microenvironment rather than a specific molecular target.