FXR agonism protects against liver injury in a rat model of intestinal failure-associated liver disease

Background: Intestinal failure-associated liver disease (IFALD) is a clinical challenge. The pathophysiol-ogy is multifactorial and remains poorly understood. Disturbed recirculation of bile salts, e.g. due to loss of bile via an enterocutaneous fistula, is considered a major contributing factor. We hypothesize that impaired signaling via the bile salt receptor FXR underlies the development of IFALD. The aim of this study was to investigate whether activation of FXR improves liver homeostasis during chronic loss of bile in rats.

Methods: To study consequences of chronic loss of bile, rats underwent external biliary drainage (EBD) or sham surgery for seven days, and the prophylactic potential of the FXR agonist INT-747 was assessed.

Results: EBD for 7 days resulted in liver test abnormalities and histological liver damage. Expression of the intestinal FXR target gene Fgf15 was undetectable after EBD, and this was accompanied by an anticipated increase in hepatic Cyp7a1 expression, indicating increased bile salt synthesis. Treatment with INT-747 improved serum biochemistry, reduced loss of bile fluid in drained rats and prevented development of drainage-associated histological liver injury.

Conclusions: EBD results in extensive hepatobiliary injury and cholestasis. These data suggest that FXR activation might be a novel therapy in preventing liver dysfunction in patients with intestinal failure.

Relevance for patients: This study demonstrates that chronic loss of bile causes liver injury in rats. Abro-gated recycling of bile salts impairing of enterohepatic bile salt/FXR signaling underlies these pathological changes, as administration of FXR agonist INT747 prevents biliary drainage-induced liver damage. Phar-macological activation of FXR might be a therapeutic strategy to treat disorders accompanied by a per-turbed enterohepatic circulation such as intestinal failure-associated liver disease.