title: Identification in human urine and blood of a novel selenium metabolite, Se-methylselenoneine, a potential biomarker of metabolization in mammals of the naturally occurring selenoneine, by HPLC coupled to electrospray hybrid linear ion trap-orbital ion trap MS.
abstract: Speciation analysis of selenium in human urine allowed for the first time the identification of a novel selenium metabolite, Se-methylselenoneine. Despite a concentration at low ppb level, its characterization was achieved after sample purification by solid phase extraction (SPE) followed by the parallel coupling of the bidimensional RP/HILIC chromatography with ICP-MS and ESI-LTQ Orbitrap MS detection. To confirm its biological significance with regards to selenoneine, the recently discovered analog of ergothioneine, and to discard the possibility of sample preparation artifacts, a new method was developed to monitor its actual presence, as well as the occurrence of its sulfur and/or non-methylated analogs, in non-preconcentrated urine and blood samples of non-supplemented humans. It consisted in a HILIC ESI-MS(3) method in high resolution mode (resolution 30 000 at m/z 400) with large isolation width windows for precursor ions. These two particular settings allowed respectively to keep observing the specific mass defect of selenium- and sulfur-containing molecules and to maintain the characteristic selenium pattern in product ions created through MS(n) fragmentations. As a result, all four metabolites were detected in blood and three of them in urine. Moreover, different ratios "methylated/non-methylated" were observed between urine and blood samples, which seemed to indicate their active metabolization. The analytical tool developed here will be of a great importance to further study the occurrence and the potential metabolic role in mammalian organelles, cells and fluids of these very particular and promising redox metabolites.
authors.affiliation: Laboratoire de Chimie Analytique Bio Inorganique et Environnement, IPREM, Université de Pau et des Pays de l'Adour / CNRS UMR 5254, Hélioparc, Avenue du Pr. Angot, Pau, France.
authors.forename: Marlène
authors.initials: M
authors.lastname: Klein
authors.forename: Laurent
authors.initials: L
authors.lastname: Ouerdane
authors.forename: Maïté
authors.initials: M
authors.lastname: Bueno
authors.forename: Florence
authors.initials: F
authors.lastname: Pannier
mesh_terms: D015415:Biomarkers / Q000097:blood / Q000652:urine; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006639:Histidine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000652:urine; D006801:Humans; D008745:Methylation; D016566:Organoselenium Compounds / Q000097:blood* / Q000378:metabolism / Q000652:urine*; D015203:Reproducibility of Results; D012643:Selenium / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013455:Sulfur / Q000378:metabolism
chemical_list: D015415:Biomarkers; D016566:Organoselenium Compounds; C561546:Se-methylselenoneine; C550322:selenoneine; D006639:Histidine; D013455:Sulfur; D012643:Selenium