Intestinal mucus layer and epithelial glycocalyx

The intestinal mucus layer and epithelial glycocalyx constitute a multi-layered physicochemical barrier that separates the luminal contents from the underlying intestinal epithelium. The mucus layer, primarily composed of the gel-forming mucin MUC2, acts as a sieve and lubricant, while the glycocalyx is a dense network of membrane-bound mucins and carbohydrates that provides a final protective shield and facilitates cell signaling (Johansson et al., 2011, PubMed: 21423175; Pelaseyed et al., 2014, PubMed: 24741103). This system is crucial for maintaining gut homeostasis by preventing the translocation of commensal and pathogenic bacteria while allowing for the absorption of nutrients (McGuckin et al., 2011, PubMed: 21386865). Dysregulation of this barrier, characterized by thinning or altered glycosylation, is a hallmark of inflammatory bowel diseases and can facilitate the development of colorectal cancer (Schoultz & Keita, 2020, PubMed: 32455582). Therapeutic strategies targeting this interface include mucoadhesive drug delivery systems to increase local drug concentration and agents designed to restore or reinforce the barrier's integrity (Cone, 2009, PubMed: 19133304).

Other names

Intestinal mucosal barrierGut mucus barrierEnteric glycocalyxMucus-glycocalyx interfaceIntestinal surface layer

Mucoadhesion to increase drug residence time, mucolysis to reduce viscosity for drug penetration, and barrier reinforcement to prevent pathogen translocation (Cone, 2009, PubMed: 19133304; Schoultz & Keita, 2020, PubMed: 32455582).