Cholestatic liver disease overlap syndromes

Steroidal scaffolds as FXR and GPBAR1 ligands: from chemistry to therapeutical application

Bile acids (BAs) are experiencing a new life. Next to their ancestral roles in lipid digestion and solubilization, BAs are today recognized signaling molecules involved in many physiological functions. These signaling pathways involve the activation of metabolic nuclear receptors, mainly the BA sensor FXR, and the dedicated membrane G protein-coupled receptor, GPBAR1 (TGR5). As a consequence, the discovery of GPBAR1/FXR selective or dual modulators represents an important answer to the urgent demand of new pharmacological opportunity for several human diseases including dyslipidemia, cholestasis, nonalcoholic steatohepatitis, Type 2 diabetes and inflammation. Targeted oriented discovery of natural compounds and medicinal chemistry manipulation have allowed the development of promising drug candidates.

Overlap syndromes of autoimmune hepatitis: diagnosis and treatment

Some patients with autoimmune liver disease have characteristics of cholestasis, as well as of autoimmune hepatitis. Despite the fact that this is a relatively frequent clinical condition seen in referral centers for liver diseases, there is little evidence as regards the clinical management of these syndromes due to their low prevalence and the lack of standardized definitions and diagnostic criteria. This is relevant, given that published studies report that there is a lower therapeutic response and poorer outcome in patients with overlap syndrome than in those presenting solely with autoimmune hepatitis. Whether overlap syndromes are distinct entities or the presence of 2 concurrent diseases is still a subject of debate. They should be suspected in autoimmune hepatitis patients that present with signs of cholestasis, as it is known that overlap behavior tends to be more aggressive, with higher rates of cirrhosis and the need for liver transplantation. Treatment response is also poorer and should be directed at the predominant component. Standardized definitions are necessary so that these syndromes can be studied in controlled clinical trials.

Diagnosis and management of overlap syndromes

Overlapping features between autoimmune hepatitis (AIH) and cholestatic disorders (primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), or indeterminate cholestasis), so-called overlap syndromes, usually have a progressive course toward cirrhosis and liver failure without adequate treatment. The diagnosis of overlap syndrome requires the prominent features of classic AIH and secondary objective findings of PBC or PSC. Empiric treatment for patients with AIH-PBC overlap is immunosuppressive therapy plus ursodeoxycholic acid. Empiric treatment for patients with AIH-PSC and AIH-cholestatic overlap is immunosuppressive therapy with or without ursodeoxycholic acid. Liver transplantation is indicated for patients who have end-stage liver disease.

Primary biliary cirrhosis in 2014

PURPOSE OF REVIEW

Primary biliary cirrhosis (PBC) was first described in the 1950s as a clinical syndrome of progressive cholestatic liver disease resulting from chronic inflammatory destruction of the intrahepatic bile ducts. In the 1980s, the autoimmune nature of the disease was appreciated with the discovery of disease-specific loss of immune tolerance to the pyruvate dehydrogenase complex and subsequent development of antimitochondrial antibodies and autoreactive T cells. Then, in the 1990s, multiple clinical trials demonstrating the efficacy of ursodiol as a treatment for PBC were published, although it has been clear that ursodiol is not a cure and only delays progression in some patients.

RECENT FINDINGS

The study of PBC in the 2000s has been buoyed by two basic science advances: rapid sequencing technologies that have led to genome wide association studies, and elucidation of the role of nuclear hormone receptors in the regulation of bile salt metabolism, which has led to novel therapies under study for cholestatic diseases.

SUMMARY

Today's clinician should be able to determine which patients with PBC are likely to progress despite treatment with ursodiol and understand the putative new bile acid and immunosuppressant treatment strategies under development, as well as be aware of the recently described genetic factors at play in the development of PBC.