Urine and serum metabolomic profiling reveals that bile acids and carnitine may be potential biomarkers of primary biliary cirrhosis

In order to provide non-invasive, reliable and sensitive laboratory parameters for the diagnosis of primary biliary cirrhosis (PBC), metabolic technology of ultraperformance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF MS) was used to compare small molecule metabolites in blood and urine from patients with PBC and healthy controls. We then screened for biomarkers in the blood and urine of the patients with PBC. Data were processed by Bruker ProfileAnalysis metabonomic software and imported to SIMCA-P software, which utilized principal component analysis (PCA) to create models of patients with PBC and healthy controls. In total, 18 urinary markers were found and the levels of 11 of these urinary markers were elevated in the patients with PBC, whereas the levels of the remaining 7 markers were lower in the PBC group compared to the control group. We also identified 20 blood-based biomarkers in the patients with PBC and the levels of 9 of these markers were higher in the PBC group, whereas the levels of the remaining 11 markers were lower in the patients with PBC compared to the controls. Among these biomarkers, the levels of bile acids increased with the progression of PBC, while the levels of carnitines, such as propionyl carnitine and butyryl carnitine, decreased with the progression of PBC. In conclusion, the findings of the present study suggest that the circulating levels of bile acids and carnitine are differentially altered in patients with PBC.