Modification of gut microbes play a crucial role in the pathogenesis and progression of many disorders including liver and gastrointestinal diseases and both qualitative and quantitative changes in gut microbiota are correlated to liver disease. Intestinal dysbiosis can disturb the integrity of the intestinal barrier that causes pathological bacterial translocation and the initiation of an inflammatory response in the liver. Evidences suggest that in order to support symbiosis and prevention from pathological bacterial translocation, antimicrobial proteins (AMPs) including a-defensins and C-type lectins are expressed in the gastrointestinal tract.

Patients with liver disease are reported with bacterial translocation and reduced expression of certain antimicrobial proteins in the gut that determine the strategy to elevate intestinal concentrations of antimicrobial proteins or their production by intestinal epithelial cells, which in turn, can help in the prevention of liver disease.

Antibiotics

Mounting evidences suggest that non-absorbable antibiotics have a beneficial effect on NASH and alcoholic liver disease, and can be commonly used to manage patients with cirrhosis. Antibiotics exert a beneficial effect by reducing bacterial overgrowth and preventing bacterial translocation, however, no evidence claims that this effect can be attained by increased expression of antimicrobial proteins. The present study showed that non-absorbable antibiotics could maintain IL-22 production by ILC3 s during ethanol diet. Hence, alterations in the microbial metabolome, the composition of microbiota, or host immunity due to antibiotics might produce indirect antimicrobial responses.

Probiotics and prebiotics

Probiotics control antimicrobial defense such as probiotic Escherichia coli Nissle and lactobacilli have the potential to strongly induced the expression of human beta-defensin-2 in epithelial cell lines. Additionally, lactobacilli strains can upregulate enterocyte human beta-defensin 2 (hBD-2) production in vitro along with resistance to the antimicrobial effects of this defensin. Besides, the beneficial effect of probiotics in inducing AMP, they exert an effect on cytokine-producing innate cells in the mucosa that can increase the expression of Reg3 lectins, indicative of positive effect of bacteria in enhancing the immune response to protect the host from pathogens during ethanol-induced liver disease.

Source: Hendrikx T, Schnabl B. Antimicrobial proteins: intestinal guards to protect against liver disease. J Gastroenterol. 2019 Mar;54(3):209-217.