title: Metabolic profiling of bile acids in human and mouse blood by LC-MS/MS in combination with phospholipid-depletion solid-phase extraction.
abstract: To obtain a more comprehensive profile of bile acids (BAs) in blood, we developed an ultrahigh performance liquid chromatography/multiple-reaction monitoring-mass spectrometry (UPLC-MRM-MS) method for the separation and detection of 50 known BAs. This method utilizes phospholipid-depletion solid-phase extraction as a new high-efficiency sample preparation procedure for BA assay. UPLC/scheduled MRM-MS with negative ion electrospray ionization enabled targeted quantitation of 43 and 44 BAs, respectively, in serum samples from seven individuals with and without fasting, as well as in plasma samples from six cholestatic gene knockout mice and six age- and gender-matched wild-type (FVB/NJ) animals. Many minor BAs were identified and quantitated in the blood for the first time. Method validation indicated good quantitation precision with intraday and interday relative standard deviations of ≤9.3% and ≤10.8%, respectively. Using a pooled human serum sample and a pooled mouse plasma sample as the two representative test samples, the quantitation accuracy was measured to be 80% to 120% for most of the BAs, using two standard-substance spiking approaches. To profile other potential BAs not included in the 50 known targets from the knockout versus wild-type mouse plasma, class-specific precursor/fragment ion transitions were used to perform UPLC-MRM-MS for untargeted detection of the structural isomers of glycine- and taurine-conjugated BAs and unconjugated tetra-hydroxy BAs. As a result, as many as 36 such compounds were detected. In summary, this UPLC-MRM-MS method has enabled the quantitation of the largest number of BAs in the blood thus far, and the results presented have revealed an unexpectedly complex BA profile in mouse plasma.
authors.affiliation: University of Victoria-Genome BC Proteomics Centre, University of Victoria , Vancouver Island Technology Park, 3101-4464 Markham Street, Victoria, British Columbia V8Z 7X8, Canada.
authors.forename: Jun
authors.initials: J
authors.lastname: Han
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Renxue
authors.initials: R
authors.lastname: Wang
authors.forename: Juncong
authors.initials: J
authors.lastname: Yang
authors.forename: Victor
authors.initials: V
authors.lastname: Ling
authors.forename: Christoph H
authors.initials: CH
authors.lastname: Borchers
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000502:physiology; D000818:Animals; D001647:Bile Acids and Salts / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods*; D005215:Fasting / Q000502:physiology; D005260:Female; D064368:Healthy Volunteers; D006720:Homozygote; D006801:Humans; D008297:Male; D055432:Metabolomics / Q000379:methods*; D051379:Mice; D018345:Mice, Knockout; D010743:Phospholipids / Q000302:isolation & purification*; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D000097202:ATP-Binding Cassette Sub-Family B Member 4
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D001647:Bile Acids and Salts; D010743:Phospholipids; D000097202:ATP-Binding Cassette Sub-Family B Member 4