Intestinal failure-associated liver disease: Risks and regression

Administration of antibiotics contributes to cholestasis in pediatric patients with intestinal failure via the alteration of FXR signaling

The link between antibiotic treatment and IF-associated liver disease (IFALD) is unclear. Here, we study the effect of antibiotic treatment on bile acid (BA) metabolism and investigate the involved mechanisms. The results showed that pediatric IF patients with cholestasis had a significantly lower abundance of BA-biotransforming bacteria than patients without cholestasis. In addition, the BA composition was altered in the serum, feces, and liver of pediatric IF patients with cholestasis, as reflected by the increased proportion of primary BAs. In the ileum, farnesoid X receptor (FXR) expression was reduced in patients with cholestasis. Correspondingly, the serum FGF19 levels decreased significantly in patients with cholestasis. In the liver, the expression of the rate-limiting enzyme in bile salt synthesis, cytochrome P450 7a1 (CYP7A1), increased noticeably in IF patients with cholestasis. In mice, we showed that oral antibiotics (gentamicin, GM or vancomycin, VCM) reduced colonic microbial diversity, with a decrease in both Gram-negative bacteria (GM affected Eubacterium and Bacteroides) and Gram-positive bacteria (VCM affected Clostridium, Bifidobacterium and Lactobacillus). Concomitantly, treatment with GM or VCM decreased secondary BAs in the colonic contents, with a simultaneous increase in primary BAs in plasma. Moreover, the changes in the colonic BA profile especially that of tauro-beta-muricholic acid (TβMCA), were predominantly associated with the inhibition of the FXR and further altered BA synthesis and transport. In conclusion, the administration of antibiotics significantly decreased the intestinal microbiota diversity and subsequently altered the BA composition. The alterations in BA composition contributed to cholestasis in IF patients by regulating FXR signaling.

Using antibiotics during intestinal failure in children may lead to the development of liver disease. Microbiota in the gut play vital roles in balancing the digestive system, including transforming bile acids (BAs) secreted by the liver into forms that help us digest food. Wai Cai and Ying Wang at Shanghai Jiao Tong University in China and co-workers examined samples from 46 children treated with antibiotics for intestinal failure. The patients who also had cholestasis – disrupted production and flow of bile – had far fewer BA-transforming bacteria in their gut than those without cholestasis. They also had altered expression of a crucial BA receptor protein. Experiments on mice showed that treatment with two different antibiotics reduced microbiota diversity, which in turn influenced BA receptor signaling and altered BA composition, contributing to cholestasis.