BACKGROUND: Since the introduction of liquid chromatography-mass spectrometry (LC/MS) for assessing vitamin D status, it has been shown that the C-3 epimer can account for a significant proportion of circulating 25-hydroxyvitamin D₃ (25OHD₃) concentrations in infants. However, some question whether monitoring a single MS transition at a chromatographic retention time typical for 3-epi-25OHD₃ sufficiently warrants conclusions about the identity of the substance generating the signal. Therefore, we aimed to substantiate the evidence for 3-epi-25OHD₃ in infants by collision induced dissociation (CID)-MS/MS product ion scans. A second objective was mass spectrometric investigation of the presence and prevalence of the 3-epi metabolite in serum from adults. METHODS: Serum samples from six infants and 32 adults were studied using an ultra performance LC/tandem MS (UPLC/MS/MS) method designed to separate the 3-epi-25OHD₃ from 25OHD₃. Samples were submitted to liquid/liquid extraction and Sephadex LH-20 fractionation, prior to column-switching UPLC with MS/MS recording of CID product ion spectra of the [M+H](+) precursor ion. The respective standards were analyzed under identical UPLC/MS/MS conditions for comparison. RESULTS: In the chromatograms of all samples, two peaks eluted with retention characteristics and spectra closely matching those observed for the 25OHD₃ and the 3-epi standards. The percentage of the 3-epi metabolite relative to 25OHD₃ in infants ranged from 15% to 41%, and in adults from 2.5% to 17%. CONCLUSIONS: This preliminary finding suggests that the prevalence of 3-epi-25OHD₃ in serum of infants is considerable, and that even in adults the concentrations of this form should not be neglected.
BACKGROUND: Since the introduction of liquid chromatography-mass spectrometry (LC/MS) for assessing vitamin D status, it has been shown that the C-3 epimer can account for a significant proportion of circulating 25-hydroxyvitamin D₃ (25OHD₃) concentrations in infants. However, some question whether monitoring a single MS transition at a chromatographic retention time typical for 3-epi-25OHD₃ sufficiently warrants conclusions about the identity of the substance generating the signal. Therefore, we aimed to substantiate the evidence for 3-epi-25OHD₃ in infants by collision induced dissociation (CID)-MS/MS product ion scans. A second objective was mass spectrometric investigation of the presence and prevalence of the 3-epi metabolite in serum from adults. METHODS: Serum samples from six infants and 32 adults were studied using an ultra performance LC/tandem MS (UPLC/MS/MS) method designed to separate the 3-epi-25OHD₃ from 25OHD₃. Samples were submitted to liquid/liquid extraction and Sephadex LH-20 fractionation, prior to column-switching UPLC with MS/MS recording of CID product ion spectra of the [M+H](+) precursor ion. The respective standards were analyzed under identical UPLC/MS/MS conditions for comparison. RESULTS: In the chromatograms of all samples, two peaks eluted with retention characteristics and spectra closely matching those observed for the 25OHD₃ and the 3-epi standards. The percentage of the 3-epi metabolite relative to 25OHD₃ in infants ranged from 15% to 41%, and in adults from 2.5% to 17%. CONCLUSIONS: This preliminary finding suggests that the prevalence of 3-epi-25OHD₃ in serum of infants is considerable, and that even in adults the concentrations of this form should not be neglected.
Authors: Christopher T Sempos; Annemieke C Heijboer; Daniel D Bikle; Jens Bollerslev; Roger Bouillon; Patsy M Brannon; Hector F DeLuca; Glenville Jones; Craig F Munns; John P Bilezikian; Andrea Giustina; Neil Binkley Journal: Br J Clin Pharmacol Date: 2018-07-17 Impact factor: 4.335
Authors: Frederick G Strathmann; Katerina Sadilkova; Thomas J Laha; Susan E LeSourd; Joshua A Bornhorst; Andrew N Hoofnagle; Rhona Jack Journal: Clin Chim Acta Date: 2011-09-29 Impact factor: 3.786
Authors: Karen W Phinney; Johanna E Camara; Susan S-C Tai; Lane C Sander; Stephen A Wise; Linde A C De Grande; Linda M Thienpont; Antonio M Possolo; Blaza Toman; Christopher T Sempos; Joseph M Betz; Paul M Coates Journal: J AOAC Int Date: 2017-06-16 Impact factor: 1.913
Authors: Christopher D Chouinard; Vinicius Wilian D Cruzeiro; Robin H J Kemperman; Nicholas R Oranzi; Adrian E Roitberg; Richard A Yost Journal: Int J Mass Spectrom Date: 2018-05-22 Impact factor: 1.986