Animal models in primary biliary cirrhosis and primary sclerosing cholangitis

Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are immune-mediated cholangiopathies with enigmatic etiology and pathogenesis. They have distinct clinical, laboratory, immunological, and histomorphological characteristics. Well-characterized animal models for PBC and PSC are utterly needed to develop novel pathogenetic concepts and to study innovative treatment strategies. The aim of the current paper is to outline the characteristics of ideal PBC and PSC animal models and to contrast this with a real-life up-to-date overview of currently available mouse models. Although some of this models show several individual characteristics of PBC and PSC, it is obvious that all of them have substantial and important limitations. Nevertheless, some may be beneficial to study certain pathophysiological aspects. Potential cholangiopathy animal models should be systematically investigated in regard to elevated serum alkaline phosphatase, bilirubin, and bile acid levels; immunological abnormalities; and longitudinal studies in regard to their liver phenotype. We herein propose a common systematic workup for potential models based on the fact that there are some intriguing disease combinations in specific genetically modified mice and recommend a stepwise process in regard to model characterization with methodical harvesting and screening of numerous organs for potential concomitant diseases. Due to the complex nature of both cholangiopathies, it seems to be very likely that no single perfect PBC or PSC model will ever be generated. The models outlined herein will certainly help to clarify specific pathogenetic aspects and even more important may turn out to be suitable to test potential drugs for treatment.