title: Quantification of plasma homocitrulline using hydrophilic interaction liquid chromatography (HILIC) coupled to tandem mass spectrometry.
abstract: Homocitrulline (HCit), an amino acid formed by the carbamylation of ε-amino groups of lysine residues, is considered a promising biomarker for monitoring diseases such as chronic renal failure and atherosclerosis. This paper describes a tandem mass spectrometric method for total, protein-bound and free HCit measurement in plasma samples. HCit was separated from other plasma components by hydrophilic interaction liquid chromatography. Detection was achieved by monitoring transitions of 190.1 > 127.1 and 190.1 > 173.1 for HCit, and 183.1 > 120.2 for d(7)-citrulline used as internal standard. This method allowed HCit quantification within 5.2 min and was precise (inter-assay CV < 5.85%), accurate (mean recoveries ranging from 97% to 106%), and exhibited a good linearity from 10 nmol/L to 1.6 μmol/L. Plasma samples from control and uremic mice (n = 10) were analyzed. In control mice, mean total plasma HCit concentration was 0.78 ± 0.12 μmol/mol amino acids, whereas it was increased 2.7-fold in uremic mice plasma, reaching 2.10 ± 0.50 μmol/mol amino acids (p < 0.001). In conclusion, this method exhibits good analytical performances and meets the criteria of sensitivity suitable for HCit concentration assessment in plasma samples.
authors.affiliation: Laboratory of Pediatric Biology and Research, American Memorial Hospital, University Hospital of Reims, 47 Rue Cognacq-Jay, 51092 Reims, France. sjaisson@chu-reims.fr
authors.forename: Stéphane
authors.initials: S
authors.lastname: Jaisson
authors.forename: Laëtitia
authors.initials: L
authors.lastname: Gorisse
authors.forename: Christine
authors.initials: C
authors.lastname: Pietrement
authors.forename: Philippe
authors.initials: P
authors.lastname: Gillery
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D002956:Citrulline / Q000031:analogs & derivatives* / Q000097:blood; D005260:Female; D057927:Hydrophobic and Hydrophilic Interactions; D016014:Linear Models; D051379:Mice; D008810:Mice, Inbred C57BL; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014511:Uremia / Q000652:urine
chemical_list: C001352:homocitrulline; D002956:Citrulline