Widely quasi-quantitative analysis enables temporal bile acids-targeted metabolomics in rat after oral administration of ursodeoxycholic acid

Abstract

Bile acid (BA) pool homeostasis can be disturbed when cholestasis, and ursodeoxycholic acid (UDCA) treatment is able to rectify the perturbed pool. Efforts were made here to propose a strategy enabling BAs-focused widely quantitative metabolomics and subsequently to lucubrate BA pool fluctuation trajectory in rats after dosing UDCA. A so-called universal metabolome standard (UMS) sample containing numerous natural BAs was constructed by involving various available BAs-enriched matrices. In-depth chemical characterization was conducted for UMS to capture as many BAs as possible. Diverse survey experiments were performed on Qtrap-MS to search BAs, and IT-TOF-MS was deployed to provide high-resolution m/z values for both precursor and fragment ion species. After structural annotation for 120 BAs, in total, online energy-resolved MS was subsequently programmed to pursue superior parameters for certain BAs, particularly BAs bearing two conjugated moieties. UMS was serially diluted to generate calibration sample set, and the regressive calibration curves, 120 ones in total, were responsible for converting each analyte response to quasi-content (1/dilution fold). The validated widely quasi-quantitative program was then applied to profile BA pool shift trajectories against time in UDCA- and vehicle-treated rats. Mild variations were observed for the quantitative pattern of BA pool from vehicle group, whereas UDCA could significantly shape BAs sub-metabolome. Significant increments occurred for the contents of not only the downstream BAs, but some upstream molecules in BA metabolic network. The shift levels of BAs were primarily governed by their distances away from UDCA. Fourteen differential BAs were involved for absolute quantitation to generate the concentration vs. time patterns, and dramatic upgradation occurred for most BAs, consolidating the variations transmitted from large-scale quasi-quantitative metabolomics. Above all, current study revealed the quasi-quantitative details of BA pool fluctuation initiated by UDCA-treatment, and more importantly, provided a promising approach for temporal BAs-targeted metabolomics.

Keywords: Bile acid pool; Temporal BAs-targeted metabolomics; Trajectory; Ursodeoxycholic acid; Widely quasi-quantitative analysis.