The gastrointestinal mucus system in health and disease

By M. Johansson, H. Sjövall, G. Hansson. Nature Reviews Gastroenterology &Hepatology, 2013

1,294 citations recorded by the source corpus.

Mucins—large, highly glycosylated proteins—are important for the luminal protection of the gastrointestinal tract. Enterocytes have their apical surface covered by transmembrane mucins and goblet cells produce the secreted gel-forming mucins that form mucus. The small intestine has a single unattached mucus layer, which in cystic fibrosis becomes attached, accounting for the intestinal manifestations of this disease. The stomach and colon have two layers of mucus; the inner layer is attached and the outer layer is less dense and unattached. In the colon, the outer mucus layer is the habitat for commensal bacteria. The inner mucus layer is impervious to bacteria and is renewed every hour by surface goblet cells. The crypt goblet cells have the ability to restitute the mucus layer by secretion, for example after an ischaemic challenge. Proteases of certain parasites and some bacteria can cleave mucins and dissolve the mucus as part of their pathogenicity. The inner mucus layer can, however, also become penetrable to bacteria by several other mechanisms, including aberrations in the immune system. When bacteria reach the epithelial surface, the immune system is activated and inflammation is triggered. This mechanism might occur in some types of ulcerative colitis.

Subfields: Food Science, Nutrition and Dietetics, Surgery

View Paper: https://www.semanticscholar.org/paper/b21942740ff39481309d9d26cd81afcdca571824

How researchers see this paper

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In Food Science

1. Bernard Henrissat
2. G. Núñez
3. F. Bäckhed
4. E. Martens
5. Ted G. Dinan
6. J. Cryan

In Nutrition and Dietetics

1. G. Núñez
2. F. Bäckhed
3. A. Varki
4. J. Cryan

In Surgery

1. J. Cryan
2. Ted G. Dinan
3. G. Núñez
4. M. Johansson
5. G. Hansson
6. F. Bäckhed
7. A. Varki
8. Justin L. Sonnenburg

Citations in the corpus

• The composition of the gut microbiota shapes the colon mucus barrier (2014, positive): “Mucus covers the intestinal epithelium, but the principle of this mucus protection is solved differently along the intestinal tract [7].”
• Biological roles of glycans (2016, background): “In addition to the polymers mentioned above, the dense layer of mucins that coats many epithelial surfaces such as the inner lining of airways and intestines provides critical barrier functions, including protection against the invasion by microorganisms that live within the lumen (139, 418, [448] [”
• The mucus and mucins of the goblet cells and enterocytes provide the first defense line of the gastrointestinal tract and interact with the immune system (2014, neutral): “It can thus be suggested that a penetrable inner mucus layer allowing bacteria to reach the epithelial cells in large quantities is a common mechanism that underlies many forms of acute or chronic colonic inflammation (35).”
• A dietary fiber-deprived gut microbiota degrades the colonic mucus barrier and enhances pathogen susceptibility (2016, positive): “A key nutritional aspect of the mucus layer for gut bacteria is its high polysaccharide content, with up to 80% of the mucin biomass being composed of mostly O-linked glycans (Johansson et al., 2013).”
• Gut instincts: microbiota as a key regulator of brain development, ageing and neurodegeneration (2017, background): “…and its mucous layer have many functions, including the regulation of nutrient and fluid absorption from the gut lumen in addition to serving as a physical barrier from invading pathogens or harmful substances (Farhadi et al. 2003; Scaldaferri et al. 2012; Johansson et al. 2013; Kelly et al. 2015).”