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Pauwels S, Jans I, Billen J, Heijboer A, Verstuyf A, Carmeliet G, Mathieu C, Maestro M, Waelkens E, Evenepoel P, Bouillon R, Vanderschueren D, Vermeersch P. 1β,25-Dihydroxyvitamin D 3: A new vitamin D metabolite in human serum. J Steroid Biochem Mol Biol 2017; 173:341-348. [PMID: 28193495 DOI: 10.1016/j.jsbmb.2017.02.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 02/03/2017] [Accepted: 02/08/2017] [Indexed: 01/08/2023]
Abstract
BACKGROUND The measurement of 1α,25(OH)2D3 in human serum poses a true challenge as concentrations are very low and structurally similar metabolites can interfere. MATERIALS AND METHODS During optimization of our in-house LC-MSMS method for serum 1α,25(OH)2D3 a previously co-eluting isobaric interference was separated. The isobar was identified as 1β,25(OH)2D3 by comparing retention time and fragmentation spectra to standards (other isobaric dihydroxylated vitamin D3 analogs). 1β,25(OH)2D3 showed specific cluster formation (water), not present in 1α,25(OH)2D3. 1β,25(OH)2D3 was measured in serum of apparently healthy human volunteers (n=20), patients with high serum 25-hydroxyvitamin D [25(OH)D] concentrations (>50ng/mL) (n=33 among which 4 with very high levels (>150ng/mL)) and patients with kidney failure (n=68; 39 stage 1-3, 29 stage 4-5). Pearson's r was calculated for correlations and Mann-Whitney statistic to compare group medians. RESULTS Median serum 1β,25(OH)2D3 was 11pg/mL in apparently healthy volunteers and increased to 20pg/mL for serum 25(OH)D concentrations above 80ng/mL (n=22) (p<0.0001). 1β,25(OH)2D3 concentrations were significantly correlated to serum 25(OH)D concentrations (r=0.85) for the combined results from healthy volunteers and patient sera (n=53) (p<0.0001). For patients with kidney failure, median serum 1β,25(OH)2D3 was 7pg/mL and not different from the median level in healthy volunteers (p=0.06). The median concentration did not vary with different stages. CONCLUSIONS We present evidence for the widespread presence of 1β,25(OH)2D3, a new vitamin D metabolite, in human serum. The level increases with rising serum 25(OH)D concentrations and is particularly high in patients with very high 25(OH)D levels. We previously demonstrated that 1β,25(OH)2D3 is a poor genomic agonist but a potent non-genomic antagonist of 1α,25(OH)2D3. The clinical implications of the presence of this analog therefore require further exploration.
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Affiliation(s)
- Steven Pauwels
- Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; Department of Cardiovascular Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Ivo Jans
- Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Jaak Billen
- Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; Laboratory of Clinical and Experimental Endocrinology, KU Leuven, 3000 Leuven, Belgium
| | - Annemieke Heijboer
- Endocrine Laboratory, Department of Clinical Chemistry, VU University medical center, Amsterdam, the Netherlands
| | - Annemieke Verstuyf
- Laboratory of Clinical and Experimental Endocrinology, KU Leuven, 3000 Leuven, Belgium
| | - Geert Carmeliet
- Laboratory of Clinical and Experimental Endocrinology, KU Leuven, 3000 Leuven, Belgium
| | - Chantal Mathieu
- Laboratory of Clinical and Experimental Endocrinology, KU Leuven, 3000 Leuven, Belgium
| | - Miguel Maestro
- Department of Fundamental Chemistry, University of A Coruña, A Coruña, Spain
| | - Etienne Waelkens
- Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Pieter Evenepoel
- Department of Immunology and Microbiology, Laboratory of Nephrology, KU Leuven, 3000 Leuven, Belgium
| | - Roger Bouillon
- Laboratory of Clinical and Experimental Endocrinology, KU Leuven, 3000 Leuven, Belgium.
| | - Dirk Vanderschueren
- Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; Laboratory of Clinical and Experimental Endocrinology, KU Leuven, 3000 Leuven, Belgium
| | - Pieter Vermeersch
- Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; Department of Cardiovascular Sciences, KU Leuven, 3000 Leuven, Belgium
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Measurement of Circulating 1,25-Dihydroxyvitamin D: Comparison of an Automated Method with a Liquid Chromatography Tandem Mass Spectrometry Method. Int J Anal Chem 2016; 2016:8501435. [PMID: 27127512 PMCID: PMC4835639 DOI: 10.1155/2016/8501435] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/16/2016] [Indexed: 11/30/2022] Open
Abstract
Background. The clinical relevance of circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) is probably underappreciated, but variations in the measurement of this difficult analyte between different methods limit comparison of results. Methods. In 129 clinical samples, we compared a new automated assay with a commercially available liquid chromatography tandem mass spectrometry (LC-MS/MS) kit. Results. Median (interquartile range) 1,25(OH)2D concentrations with the automated assay and the LC-MS/MS method were 26.6 pg/mL (18.5–39.0 pg/mL) and 23.6 pg/mL (16.1–31.3 pg/mL), respectively (P = 0.001). Using the method-specific cut-offs for deficient 1,25(OH)2D levels (<20 pg/mL for the automated assay and <17 pg/mL for the LC-MS/MS method), the percentage of patients classified as 1,25(OH)2D deficient was 28.7% and 27.1%, respectively. However, concordance between the two methods for deficient levels was only 62% and the concordance correlation coefficient was poor (0.534). The regression equation resulted in an intercept of −1.99 (95% CI: −7.33–1.31) and a slope of 1.27 (95% CI: 1.04–1.52) for the automated assay. The mean bias with respect to the mean of the two methods was −3.8 (1.96 SD: −28.3–20.8) pg/mL for the LC-MS/MS method minus the automated assay. Conclusions. The two methods show only modest correlation and further standardization is required to improve reliability and comparability of 1,25(OH)2D test procedures.
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Pauwels S, Rozenski J, Jans I, Billen J, Vanderschueren D, Vermeersch P. Minimal interference from paricalcitol (Zemplar®) in underivatized 1,25-dihydroxyvitamin D LC-MS/MS assays. Clin Chim Acta 2014; 429:104-5. [DOI: 10.1016/j.cca.2013.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 11/29/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022]
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