New Therapeutic Targets in Autoimmune Cholangiopathies

Abstract

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are autoimmune cholangiopathies characterized by limited treatment options. A more accurate understanding of the several pathways involved in these diseases has fostered the development of novel and promising targeted drugs. For PBC, the characterization of the role of farnesoid X receptor (FXR) and perixosome-proliferator activated receptor (PPAR) has paved the way to several clinical trials including different molecules with choleretic and antinflammatory action. Conversely, different pathogenetic models have been proposed in PSC such as the "leaky gut" hypothesis, a dysbiotic microbiota or a defect in mechanisms protecting against bile acid toxicity. Along these theories, new treatment approaches have been developed, ranging from drugs interfering with trafficking of lymphocytes from the gut to the liver, fecal microbiota transplantation or new biliary acids with possible immunomodulatory potential. Finally, for both diseases, antifibrotic agents are under investigation. In this review, we will illustrate current understanding of molecular mechanisms in PBC and PSC, focusing on actionable biological pathways for which novel treatments are being developed.

Keywords: FXR agonists; fibrates; gut-liver axis; liver; microbiome; primary biliary cholangitis; primary sclerosing cholangitis.

Figure 1

Therapeutical targets in autoimmune cholangiopathies. FGF-19, fibroblast growth factor 19; FGFR4, fibroblast growth factor receptor 4; FXR, farnesoid X receptor; HCO${}_3^{-}$, bicarbonate; norUDCA, norursodeoxycholic acid; PPAR, Peroxisome proliferator-activated receptor; ROS, reactive oxygen species; RXR, retinoid x receptor.

Figure 2

Chemical structure of most common fibrates.