previously discussed how liver abnormalities are highly prevalent in celiac disease. Why damage to the liver occurs is unknown, and gluten toxicity and increased intestinal permeability have been proposed as factors. The following free full text article appearing in the current issue of Gastroenterology may shed light on why liver damage occurs in celiacs.
Toll-like receptors (TLRs) reside on the surface of many cells which participate in the immune system. TLRs sense molecules present in pathogens but not the host, and when the immune system senses these molecules, chemicals are released which set off inflammatory and anti-pathogen responses. One class of molecules recognized by TLRs and common to most pathogenic bacteria is lipopolysaccharides (LPS).
Gluten increases intestinal permeability in celiacs. The disruption of the intestinal barrier permits endotoxins, such as LPS, from gut bacteria to reach the portal vein of the liver triggering a TLR response from immune cells in the liver. Proinflammatory mediators are released cascading into the release of more chemicals leading to inflammation and liver damage. This may be the cause of liver damage in celiacs. Gluten itself could also trigger a liver immune response. Kupffer cells in the liver are capable of antigen presentation to T cells, along with liver dendritic cells, and could initiate a T cell response to gluten within the liver.
The following article is somewhat technical, but discusses the role of various liver cells involved in the immune process and how intestinal permeability and TLRs contribute to liver injury. The article is a good read and provides valuable information about the liver I have not seen elsewhere.
Gastroenterology Volume 130, Issue 6, Pages 1886-1900 (May 2006)
Toll-Like Receptor Signaling in the Liver
Robert F. Schwabe, Ekihiro Seki, David A. Brenner