Intestinal Mucus Layer and Mucins (A Review)

Abstract

The gastrointestinal tract, like the urinary, respiratory, reproductive tracts and the surface of the eye, has large surface areas which are in contact with the exterior environment. The mucosal tissues in the gastrointestinal tract are exposed to large number of exogenous, water or food born microbiota. Therefore, they serve as access routes for different types of bacteria, parasites, viruses, enzymes and toxins. In order to protect the mucosal tissues against pathogens and aggressive enzymes, which are necessary in digestive processes, they are covered by a resident microbial flora and also by a viscoelastic adherent mucous gel layer. The mucus layer acts as the first line of defense against threats and also as a positive environment for beneficial endogenous microbiota adapted for symbiotic living. The quantity and quality of mucus layers varies throughout the gastrointestinal tube and is often changed and disrupted during the occurrence disease. A disturbed mucus layer in the intestine can result in changes in the whole organism, such as: impaired immunity, loss of weight and weak food conversion, which is important, especially in food animals. That is why several researchers have focused on these changes, both in humans and other animals, to find out methods and countermeasures, which will facilitate the best protection for the mucus layer in the intestine. In this review, we describe the composition and function of the mucus layer and mucins in the intestine.

Wild blueberry proanthocyanidins shape distinct gut microbiota profile and influence glucose homeostasis and intestinal phenotypes in high-fat high-sucrose fed mice

“…In the case of the BPF-treated mice, a trend toward increased acidic-mixed mucin was observed, suggesting that BPF may induce the secretion of sialomucins which are more resistant against microbiological degradation than neutral mucins and are impervious to bacterial glycosidases and host proteases 53 . Similar mucin profile has been reported in normal human colonic tissues, with a predominance of acidic-mixed mucin (~80%) and sparse neutral mucin (20%) 54 .…”

Immunomodulatory effects of phytogenics in chickens and pigs — A review

“…As the first line of defense, the gastrointestinal tract (GIT) has a large surface area where food degradation and absorption take place; pathogens and toxins may also gain access to the body through the GIT by destroying the mucus layer [ 4 ]. Accordingly, protection of the GIT against the incursion of pathogens and toxins is of vital importance.…”

Anti-Infective Effect of Adhesive Probiotic Lactobacillus in Fish is Correlated With Their Spatial Distribution in the Intestinal Tissue

“…The intestinal mucosa consists of one or more layers of epithelial cells overlaying a layer of loose connective tissue 13 . The mucosa is covered with a protective mucus layer 14 .…”