Metabolic profiling of bile in cholangiocarcinoma using in vitro magnetic resonance spectroscopy

Cholangiocarcinoma (CCA) has a poor prognosis and its aetiology is inadequately understood. Magnetic resonance spectroscopy (MRS) of bile may provide insights into the pathogenesis of CCA and help identify novel diagnostic biomarkers. The aim of this study was to compare the chemical composition of bile from patients with CCA with that of bile from patients with benign biliary disease. Magnetic resonance spectra were acquired from the bile of five CCA patients and compared with MRS of control bile from patients with benign biliary disease (seven with gallstones, eight with sphincter of Oddi dysfunction [SOD], five with primary sclerosing cholangitis [PSC]). Metabolic profiles were compared using both univariate and multivariate pattern-recognition analysis. Univariate analysis showed that levels of glycine-conjugated bile acids were significantly increased in patients with CCA, compared with the benign disease groups (P= 0.002). 7β primary bile acids were significantly increased (P= 0.030) and biliary phosphatidylcholine (PtC) levels were reduced (P= 0.010) in bile from patients with CCA compared with bile from gallstone patients. These compounds were also of primary importance in the multivariate analysis: the cohorts were differentiated by partial least squares discriminant analysis (PLS-DA). These preliminary data suggest that altered bile acid and PtC metabolism play an important role in CCA aetiopathogenesis and that specific metabolites may have potential as future biomarkers.