[Gastrointestinal mucus]

Gastrointestinal mucus (GIMu) is a viscoelastic gel, which covers the surface of the entire digestive tract. The main component of GIMu is mucin, which is a high molecular weight glycoprotein. Mucin is composed of a central peptide core with polysaccharide chains arranged radially from the core ("bottle brushappearance"). The carbohydrates are very hydrophilic and, therefore, able to bind large amounts of water, which partly accounts for the gel-forming properties of GIMu. GIMu has an important function as a barrier against large particles, H+ ions and pepsin, carcinogens, certain macromolecules and microorganisms. GIMu seems to be involved in the pathogenesis of gastroduodenal ulceration, inflammatory bowel disease, gastrointestinal malignancies, gallbladder stones and infectious diarrhoeal diseases. GIMu is also an important factor in maintaining the normal microbial intestinal homeostasis. In the future, a more detailed knowledge about the molecular structure and function of GIMu may lead to new diagnostic and therapeutic strategies for gastrointestinal diseases.