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Spyksma EE, Alexandridou A, Mai K, Volmer DA, Stokes CS. An Overview of Different Vitamin D Compounds in the Setting of Adiposity. Nutrients 2024; 16:231. [PMID: 38257127 PMCID: PMC10820956 DOI: 10.3390/nu16020231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/05/2024] [Accepted: 01/06/2024] [Indexed: 01/24/2024] Open
Abstract
A large body of research shows an association between higher body weight and low vitamin D status, as assessed using serum 25-hydroxyvitamin D concentrations. Vitamin D can be metabolised in adipose tissue and has been reported to influence gene expression and modulate inflammation and adipose tissue metabolism in vitro. However, the exact metabolism of vitamin D in adipose tissue is currently unknown. White adipose tissue expresses the vitamin D receptor and hydroxylase enzymes, substantially involved in vitamin D metabolism and efficacy. The distribution and concentrations of the generated vitamin D compounds in adipose tissue, however, are largely unknown. Closing this knowledge gap could help to understand whether the different vitamin D compounds have specific health effects in the setting of adiposity. This review summarises the current evidence for a role of vitamin D in adipose tissue and discusses options to accurately measure vitamin D compounds in adipose tissue using liquid chromatography tandem mass spectrometry (LC/MS-MS).
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Affiliation(s)
- Eva E. Spyksma
- Food and Health Research Group, Faculty of Life Sciences, Humboldt University Berlin, 14195 Berlin, Germany;
- Bioanalytical Chemistry, Department of Chemistry, Humboldt University Berlin, 12489 Berlin, Germany; (A.A.); (D.A.V.)
| | - Anastasia Alexandridou
- Bioanalytical Chemistry, Department of Chemistry, Humboldt University Berlin, 12489 Berlin, Germany; (A.A.); (D.A.V.)
| | - Knut Mai
- Department of Endocrinology & Metabolism, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany;
- German Centre for Cardiovascular Research (DZHK), Partner Site Berlin, 10785 Berlin, Germany
- German Center for Diabetes Research, 90451 Nuremberg, Germany
- Department of Human Nutrition, German Institute of Human Nutrition, 14558 Nuthetal, Germany
| | - Dietrich A. Volmer
- Bioanalytical Chemistry, Department of Chemistry, Humboldt University Berlin, 12489 Berlin, Germany; (A.A.); (D.A.V.)
| | - Caroline S. Stokes
- Food and Health Research Group, Faculty of Life Sciences, Humboldt University Berlin, 14195 Berlin, Germany;
- Department of Molecular Toxicology, German Institute of Human Nutrition, 14558 Nuthetal, Germany
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2
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Bergagnini-Kolev MC, Hsu S, Aitken ML, Goss CH, Hoofnagle AN, Zelnick LR, Lum D, Best CM, Thummel KE, Kestenbaum BR, de Boer IH, Lin YS. Metabolism and pharmacokinetics of vitamin D in patients with cystic fibrosis. J Steroid Biochem Mol Biol 2023; 232:106332. [PMID: 37217104 PMCID: PMC10524963 DOI: 10.1016/j.jsbmb.2023.106332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/15/2023] [Accepted: 05/19/2023] [Indexed: 05/24/2023]
Abstract
Patients with cystic fibrosis (CF) commonly have lower circulating concentrations of 25-hydroxyvitamin D (25(OH)D) than healthy populations. We comprehensively compared measures of vitamin D metabolism among individuals with CF and healthy control subjects. In a cross-sectional study, serum from participants with CF (N = 83) and frequency-matched healthy control subjects by age and race (N = 82) were analyzed for: 25(OH)D2 and 25(OH)D3, 1α,25-dihydroxyvitamins D2 and D3 (1α,25(OH)2D2 and 1α,25(OH)2D3), 24,25-dihydroxyvitamin D3 (24,25(OH)2D3), 4β,25-dihydroxyvitamin D3 (4β,25(OH)2D3), 25-hydroxyvitamin D3-3-sulfate (25(OH)D3-S), and 25-hydroxyvitamin D3-3-glucuronide (25(OH)D3-G). In a 56-day prospective pharmacokinetic study, ∼25 μg deuterium-labeled 25(OH)D3 (d6-25(OH)D3) was administered intravenously to participants (N = 5 with CF, N = 5 control subjects). Serum was analyzed for d6-25(OH)D3 and d6-24,25(OH)2D3, and pharmacokinetic parameters were estimated. In the cross-sectional study, participants with CF had similar mean (SD) total 25(OH)D concentrations as control subjects (26.7 [12.3] vs. 27.7 [9.9] ng/mL) and had higher vitamin D supplement use (53% vs. 22%). However, participants with CF had lower total 1α,25(OH)2D (43.6 [12.7] vs. 50.7 [13.0] pg/mL), 4β,25(OH)2D3 (52.1 [38.9] vs. 79.9 [60.2] pg/mL), and 25(OH)D3-S (17.7 [11.6] vs. 30.1 [12.3] ng/mL) (p < 0.001 for all). The pharmacokinetics of d6-25(OH)D3 and d6-24,25(OH)D3 did not differ between groups. In summary, although 25(OH)D concentrations were comparable, participants with CF had lower 1α,25(OH)2D, 4β,25(OH)2D3, and 25(OH)D3-S concentrations than healthy controls. Neither 25(OH)D3 clearance, nor formation of 24,25(OH)2D3, appears to account for these differences and alternative mechanisms for low 25(OH)D in CF (i.e., decreased formation, altered enterohepatic recirculation) should be explored.
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Affiliation(s)
| | - Simon Hsu
- Kidney Research Institute, University of Washington, Seattle, WA 98104, USA; Division of Nephrology, Department of Medicine, School of Medicine, University of Washington, Seattle, WA 98195, USA.
| | - Moira L Aitken
- Division of Pulmonary, Critical Care and Sleep Medicine, School of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Christopher H Goss
- Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA 98195, USA; Department of Medicine, School of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Andrew N Hoofnagle
- Kidney Research Institute, University of Washington, Seattle, WA 98104, USA; Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Leila R Zelnick
- Kidney Research Institute, University of Washington, Seattle, WA 98104, USA; Division of Nephrology, Department of Medicine, School of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Dawn Lum
- Kidney Research Institute, University of Washington, Seattle, WA 98104, USA; Division of Nephrology, Department of Medicine, School of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Cora M Best
- Kidney Research Institute, University of Washington, Seattle, WA 98104, USA; Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Kenneth E Thummel
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Bryan R Kestenbaum
- Kidney Research Institute, University of Washington, Seattle, WA 98104, USA; Division of Nephrology, Department of Medicine, School of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Ian H de Boer
- Kidney Research Institute, University of Washington, Seattle, WA 98104, USA; Division of Nephrology, Department of Medicine, School of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Yvonne S Lin
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA 98195, USA
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Dejaeger M, Antonio L, Bouillon R, Moors H, Wu FCW, O'Neill TW, Huhtaniemi IT, Rastrelli G, Forti G, Maggi M, Casanueva FF, Slowikowska-Hilczer J, Punab M, Gielen E, Tournoy J, Vanderschueren D. Aging Men With Insufficient Vitamin D Have a Higher Mortality Risk: No Added Value of its Free Fractions or Active Form. J Clin Endocrinol Metab 2022; 107:e1212-e1220. [PMID: 34662423 DOI: 10.1210/clinem/dgab743] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Low total 25-hydroxyvitamin D (25(OH)D) has been associated with mortality. Whether vitamin D in its free form or 1,25-dihydroxyvitamin D (1,25(OH)2D), provide any additional information is unclear. OBJECTIVE To determine what level of 25(OH)D is predictive for mortality and if free 25(OH)D or 1,25(OH) 2 D concentrations have any added value. METHODS This prospective cohort comprised 1915 community-dwelling men, aged 40 to 79 years. Intervention included determination of association of total and free 25(OH)D and 1,25(OH) 2 D concentrations with survival status. Vitamin D results were grouped into quintiles. For total 25(OH)D, specific cutoff values were also applied. Cox proportional hazard models were used adjusted for center, body mass index, smoking, alcohol, physical activity, season of blood sample, kidney function, and number of comorbidities. RESULTS A total of 469 (23.5%) men died during a mean follow-up of 12.3 ± 3.4 years. Compared to those with normal vitamin D values (> 30 µg/L), men with a total 25(OH)D of less than 20 µg/L had an increased mortality (hazard ratio [HR] 2.03 [95% CI, 1.39-2.96]; P < .001). Likewise, men in the lowest 3 free 25(OH)D quintiles (< 4.43 ng/L) had a higher mortality risk compared to the highest quintile (HR 2.09 [95% CI, 1.34-3.25]; P < .01). Mortality risks were similar across all 1,25(OH)2D and vitamin D binding protein quintiles. CONCLUSION Aging men with vitamin D deficiency have a 2-fold increased mortality risk. Determinations of either the free fractions of vitamin D or measurement of its active form offer no additional information on mortality risks.
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Affiliation(s)
- Marian Dejaeger
- Department of Public Health and Primary Care, KU Leuven, 3000 Leuven, Belgium
- Department of Geriatrics, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Leen Antonio
- Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
- Department of Endocrinology, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Roger Bouillon
- Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
- Department of Endocrinology, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Hannes Moors
- Department of Public Health and Primary Care, KU Leuven, 3000 Leuven, Belgium
- Department of Geriatrics, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Frederick C W Wu
- Division of Endocrinology, Medicine and Health, University of Manchester, Manchester, UK
| | - Terence W O'Neill
- Centre for Epidemiology Versus Arthritis, The University of Manchester & NIHR Manchester Biomedical Research Centre, Manchester University NHS Foundation Trust, M13 9PL Manchester, UK
| | - Ilpo T Huhtaniemi
- Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Campus, London W12 ONN, UK
| | - Giulia Rastrelli
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50121 Florence, Italy
| | - Gianni Forti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50121 Florence, Italy
| | - Mario Maggi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50121 Florence, Italy
| | - Felipe F Casanueva
- Department of Medicine, Santiago de Compostela University, Complejo Hospitalario Universitario de Santiago (CHUS); CIBER de Fisiopatología Obesidad y Nutrición (CB06/03), Instituto Salud Carlos III, 15890 Santiago de Compostela, Spain
| | | | - Margus Punab
- Andrology Centre, Tartu University Hospital, 50090 Tartu, Estonia
- Institute of Clinical Medicine, University of Tartu, 50090 Tartu, Estonia
| | - Evelien Gielen
- Department of Public Health and Primary Care, KU Leuven, 3000 Leuven, Belgium
- Department of Geriatrics, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Jos Tournoy
- Department of Public Health and Primary Care, KU Leuven, 3000 Leuven, Belgium
- Department of Geriatrics, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Dirk Vanderschueren
- Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
- Department of Endocrinology, University Hospitals Leuven, 3000 Leuven, Belgium
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Filoni A, Congedo M, Lobreglio D, Caldarola G, Lobreglio G, De Simone C, Bonamonte D. Free and total vitamin D in psoriatic patients treated with biological drugs. Exp Dermatol 2021; 30:995-996. [PMID: 33687755 DOI: 10.1111/exd.14322] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/26/2021] [Accepted: 03/04/2021] [Indexed: 12/24/2022]
Affiliation(s)
- Angela Filoni
- Section of Dermatology, Perrino Hospital, Brindisi, Italy.,Section of Dermatology, Department of Biomedical Science and Human Oncology, University of Bari, Bari, Italy
| | | | - Debora Lobreglio
- Section of Dermatology, Department of Biomedical Science and Human Oncology, University of Bari, Bari, Italy
| | | | | | | | - Domenico Bonamonte
- Section of Dermatology, Department of Biomedical Science and Human Oncology, University of Bari, Bari, Italy
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Makris K, Bhattoa HP, Cavalier E, Phinney K, Sempos CT, Ulmer CZ, Vasikaran SD, Vesper H, Heijboer AC. Recommendations on the measurement and the clinical use of vitamin D metabolites and vitamin D binding protein - A position paper from the IFCC Committee on bone metabolism. Clin Chim Acta 2021; 517:171-197. [PMID: 33713690 DOI: 10.1016/j.cca.2021.03.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/10/2021] [Accepted: 03/04/2021] [Indexed: 02/08/2023]
Abstract
Vitamin D, an important hormone with a central role in calcium and phosphate homeostasis, is required for bone and muscle development as well as preservation of musculoskeletal function. The most abundant vitamin D metabolite is 25-hydroxyvitamin D [25(OH)D], which is currently considered the best marker to evaluate overall vitamin D status. 25(OH)D is therefore the most commonly measured metabolite in clinical practice. However, several other metabolites, although not broadly measured, are useful in certain clinical situations. Vitamin D and all its metabolites are circulating in blood bound to vitamin D binding protein, (VDBP). This highly polymorphic protein is not only the major transport protein which, along with albumin, binds over 99% of the circulating vitamin D metabolites, but also participates in the transport of the 25(OH)D into the cell via a megalin/cubilin complex. The accurate measurement of 25(OH)D has proved a difficult task. Although a reference method and standardization program are available for 25(OH)D, the other vitamin D metabolites still lack this. Interpretation of results, creation of clinical supplementation, and generation of therapeutic guidelines require not only accurate measurements of vitamin D metabolites, but also the accurate measurements of several other "molecules" related with bone metabolism. IFCC understood this priority and a committee has been established with the task to support and continue the standardization processes of vitamin D metabolites along with other bone-related biomarkers. In this review, we present the position of this IFCC Committee on Bone Metabolism on the latest developments concerning the measurement and standardization of vitamin D metabolites and its binding protein, as well as clinical indications for their measurement and interpretation of the results.
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Affiliation(s)
- Konstantinos Makris
- Clinical Biochemistry Department, KAT General Hospital, 14561 Athens, Greece; Laboratory for Research of the Musculoskeletal System "Th. Garofalidis", Medical School, University of Athens, Athens, Greece.
| | - Harjit P Bhattoa
- Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Etienne Cavalier
- Department of Clinical Chemistry, University of Liège, CHU de Liège, Domaine du Sart-Tilman, B-4000 Liège, Belgium
| | - Karen Phinney
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - Christopher T Sempos
- Coordinator, Vitamin D Standardization Program (VDSP), Havre de Grace, MD 21078, USA
| | - Candice Z Ulmer
- Clinical Chemistry Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Samuel D Vasikaran
- PathWest Laboratory Medicine, Fiona Stanley Hospital, Murdoch, WA, Australia
| | - Hubert Vesper
- Clinical Chemistry Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Annemieke C Heijboer
- Department of Clinical Chemistry, Endocrine Laboratory, Amsterdam Gastroenterology Endocrinology & Metabolism, Vrije Universiteit Amsterdam and University of Amsterdam, Amsterdam UMC, Amsterdam, Netherlands
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Opposite correlation of 25-hydroxy-vitamin D- and 1,25-dihydroxy-vitamin D-metabolites with gestational age, bone- and lipid-biomarkers in pregnant women. Sci Rep 2021; 11:1923. [PMID: 33479299 PMCID: PMC7820257 DOI: 10.1038/s41598-021-81452-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/06/2021] [Indexed: 01/05/2023] Open
Abstract
25-Hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25(OH)2D) need to be bound to carrier proteins to be transported to their target cells. The majority of either 25OHD or 1,25(OH)2D is bound to vitamin D-binding protein (DBP), a smaller fraction is bound to albumin and only very small amounts of 25OHD or 1,25(OH)2D are free. Albumin-bound 25OHD or 1,25(OH)2D is relatively easily available after dissociation from albumin. Thus, the sum of free and albumin-bound forms is called bioavailable 25OHD and bioavailable 1,25(OH)2D. Total 25OHD and 1,25(OH)2D are defined as the sum of free, albumin-bound and DBP-bound 25OHD and 1,25(OH)2D, respectively. This cross-sectional study in 427 pregnant women compared the correlation of the six vitamin D compounds with biomarkers of bone health, lipid metabolism, kidney function, endocrine parameters, and group B water-soluble vitamins. Among the 25OHD metabolites analysed, total 1,25(OH)2D showed clearly the best correlation with calcium, bone-specific alkaline phosphatase, adiponectin, LDL, HDL, urea, thyroxine, and group B water-soluble vitamins. When comparing the three 25OHD metabolites, both free 25OHD and bioavailable 25OHD showed overall good correlations with calcium, bone-specific alkaline phosphatase, adiponectin, LDL, HDL, urea, thyroxine, triiodothyronine, and group B water-soluble vitamins, The correlations of 1,25(OH)2D and 25OHD metabolites went always in opposite directions. Only PTH correlates always inversely with all six vitamin D compounds. In conclusion, free 25(OH)D and bioavailable 25(OH)D are more precise determinants of the vitamin D status than total 25(OH)D in normal pregnancy, whereas total 1,25(OH)2D is superior to free and bioavailable 1,25(OH)2D. Except for PTH, correlations of 25(OH)D and 1,25(OH)2D metabolites with typical clinical chemistry readouts go in opposite directions.
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Abstract
Vitamin D is essential for bone health and is known to be involved in immunomodulation and cell proliferation. Vitamin D status remains a significant health issue worldwide. However, there has been no clear consensus on vitamin D deficiency and its measurement in serum, and clinical practice of vitamin D deficiency treatment remains inconsistent. The major circulating metabolite of vitamin D, 25-hydroxyvitamin D (25(OH)D), is widely used as a biomarker of vitamin D status. Other metabolic pathways are recognised as important to vitamin D function and measurement of other metabolites may become important in the future. The utility of free 25(OH)D rather than total 25(OH)D needs further assessment. Data used to estimate the vitamin D intake required to achieve a serum 25(OH)D concentration were drawn from individual studies which reported dose-response data. The studies differ in their choice of subjects, dose of vitamin D, frequency of dosing regimen and methods used for the measurement of 25(OH)D concentration. Baseline 25(OH)D, body mass index, ethnicity, type of vitamin D (D2 or D3) and genetics affect the response of serum 25(OH)D to vitamin D supplementation. The diversity of opinions that exist on this topic are reflected in the guidelines. Government and scientific societies have published their recommendations for vitamin D intake which vary from 400-1000 IU/d (10-25 μg/d) for an average adult. It was not possible to establish a range of serum 25(OH)D concentrations associated with selected non-musculoskeletal health outcomes. To recommend treatment targets, future studies need to be on infants, children, pregnant and lactating women.
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8
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Bikle DD. The Free Hormone Hypothesis: When, Why, and How to Measure the Free Hormone Levels to Assess Vitamin D, Thyroid, Sex Hormone, and Cortisol Status. JBMR Plus 2020; 5:e10418. [PMID: 33553985 PMCID: PMC7839820 DOI: 10.1002/jbm4.10418] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/29/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
The free hormone hypothesis postulates that only the nonbound fraction (the free fraction) of hormones that otherwise circulate in blood bound to their carrier proteins is able to enter cells and exert biologic effects. In this review, I will examine four hormone groups-vitamin D metabolites (especially 25OHD), thyroid hormones (especially thyroxine [T4]), sex steroids (especially testosterone), and glucocorticoids (especially cortisol)-that are bound to various degrees to their respective binding proteins-vitamin D-binding protein (DBP), thyroid-binding globulin (TBG), sex hormone-binding globulin (SHBG), and cortisol-binding globulin (CBG)-for which a strong case can be made that measurement of the free hormone level provides a better assessment of hormonal status than the measurement of total hormonal levels under conditions in which the binding proteins are affected in levels or affinities for the hormones to which they bind. I will discuss the rationale for this argument based on the free hormone hypothesis, discuss potential exceptions to the free hormone hypothesis, and review functions of the binding proteins that may be independent of their transport role. I will then review the complications involved with measuring the free hormone levels and the efforts to calculate those levels based on estimates of binding constants and levels of both total hormone and total binding protein. In this review, the major focus will be on DBP and free 25OHD, but the parallels and differences with the other binding proteins and hormones will be highlighted. Vitamin D and its metabolites, thyroid hormones, sex steroids, and glucocorticoids are transported in blood bound to serum proteins. The tightness of binding varies depending on the hormone and the binding protein such that the percent free varies from 0.03% for T4 and 25OHD to 4% for cortisol with testosterone at 2%. Although the major function of the primary carrier proteins (DBP, TBG, SHBG, and CBG) may be to transport their respective lipophilic hormones within the aqueous media that is plasma, these proteins may have other functions independent of their transport function. For most tissues, these hormones enter the cell as the free hormone presumably by diffusion (the free hormone hypothesis), although a few tissues such as the kidney and reproductive tissues express megalin/cubilin enabling by endocytosis protein-bound hormone to enter the cell. Measuring the free levels of these protein-bound hormones is likely to provide a better measure of the true hormone status than measuring the total levels in situations where the levels and/or affinities of the binding proteins are altered. Methods to measure free hormone levels are problematic as the free levels can be quite low, the methods require separation of bound and free that could disturb the steady state, and the means of separating bound and free are prone to error. Calculation of free levels using existing data for association constants between the hormone and its binding protein are likewise prone to error because of assumptions of linear binding models and invariant association constants, both of which are invalid. © 2020 The Author. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Daniel D Bikle
- Department of Medicine University of California San Francisco USA.,Department of Medicine San Francisco VA Medical Center San Francisco CA USA
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9
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Vitamin D Supplementation Does Not Impact Resting Metabolic Rate, Body Composition and Strength in Vitamin D Sufficient Physically Active Adults. Nutrients 2020; 12:nu12103111. [PMID: 33053823 PMCID: PMC7601703 DOI: 10.3390/nu12103111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 12/30/2022] Open
Abstract
Supplementation with the most efficient form of Vitamin D (VitD3) results in improvements in energy metabolism, muscle mass and strength in VitD deficient individuals. Whether similar outcomes occur in VitD sufficient individuals' remains to be elucidated. The aim of this study is to determine the effect of VitD3 supplementation on resting metabolic rate (RMR), body composition and strength in VitD sufficient physically active young adults. Participants completed pre-supplementation testing before being matched for sunlight exposure and randomly allocated in a counterbalanced manner to the VitD3 or placebo group. Following 12 weeks of 50 IU/kg body-mass VitD3 supplementation, participants repeated the pre-supplementation testing. Thirty-one adults completed the study (19 females and 12 males; mean ± standard deviation (SD); age = 26.6 ± 4.9 years; BMI = 24.2 ± 4.1 kg·m2). The VitD group increased serum total 25(OH)D by 30 nmol/L while the placebo group decreased total serum concentration by 21 nmol/L, reaching 123 (51) and 53 (42.2) nmol/L, respectively. There were no significant changes in muscle strength or power, resting metabolic rate and body composition over the 12-week period. Physically active young adults that are VitD sufficient have demonstrated that no additional physiological effects of achieving supraphysiological serum total 25(OH)D concentrations after VitD3 supplementation.
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10
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GRASSI TIZIANA, PANICO ALESSANDRA, BAGORDO FRANCESCO, IMBRIANI GIOVANNI, GAMBINO ISABELLA, LOBREGLIO DEBORA, LOBREGLIO GIAMBATTISTA, CONGEDO MAURIZIO, DE DONNO ANTONELLA. Direct detection of free vitamin D as a tool to assess risk conditions associated with chronic plaque psoriasis. JOURNAL OF PREVENTIVE MEDICINE AND HYGIENE 2020; 61:E489-E495. [PMID: 33150238 PMCID: PMC7595072 DOI: 10.15167/2421-4248/jpmh2020.61.3.1482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 06/15/2020] [Indexed: 12/18/2022]
Abstract
Introduction Psoriasis is a major public health problem that results in high social and health costs. New approaches and methods are required to identify any conditions related to the disease and comorbidity development. The vitamin D deficiency is associated to psoriasis and could play an important role in its pathogenesis. However, the serum level of vitamin D is currently measured as total vitamin D, which is affected by wide variability. Therefore, the determination of the free form could be more significant, since it is independent of confounding factors. A cross-sectional study was performed to assess the association between chronic plaque psoriasis and serum level of free vitamin D, detected by a direct analytical method. Methods The levels of bioavailable vitamin D, total vitamin D and other metabolic parameters whose homeostasis is regulated by vitamin D were evaluated in 72 psoriasis patients and in 48 healthy controls. A direct immunoassay method was used to measure serum free vitamin D level. Analysis of covariance was performed to calculate estimated marginal means (EMM) and 95% confidence interval (CI), after adjustment for age, sex and BMI, within the two groups. Results Patients showed an EMM of 5.526 ± 0.271pg/ml, 95% CI 4.989-6.063; while controls an EMM of 6.776 ± 0.271 pg/ml, 95% CI 6.115-7.437. Conclusions Chronic plaque psoriasis patients exhibited a serum level of free vitamin D lower than controls. The direct immunoassay method could represent a useful tool to assess vitamin D status and identify a risk condition associated with the onset of the pathology.
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Affiliation(s)
- TIZIANA GRASSI
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
| | - ALESSANDRA PANICO
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
| | - FRANCESCO BAGORDO
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
- Correspondence: Francesco Bagordo, Department of Biological and Environmental Sciences and Technologies, University of Salento, via Monteroni 165, 73100 Lecce, Italy - E-mail:
| | - GIOVANNI IMBRIANI
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
| | - ISABELLA GAMBINO
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
| | - DEBORA LOBREGLIO
- Clinical Pathology Laboratory, Vito Fazzi General Hospital, Lecce, Italy
| | | | | | - ANTONELLA DE DONNO
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
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11
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Relationships between Total, Free and Bioavailable Vitamin D and Vitamin D Binding Protein in Early Pregnancy with Neonatal Outcomes: A Retrospective Cohort Study. Nutrients 2020; 12:nu12092495. [PMID: 32824958 PMCID: PMC7551024 DOI: 10.3390/nu12092495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/11/2020] [Accepted: 08/17/2020] [Indexed: 12/27/2022] Open
Abstract
Maternal vitamin D deficiency has been associated with adverse neonatal outcomes, however, existing results are inconsistent. Current data focus on total 25-hydroxyvitamin D (25(OH)D) as the common measure of vitamin D status, while additional measures including vitamin D-binding protein (VDBP) and free and bioavailable metabolites have not been explored in relation to neonatal outcomes. We examined whether VDBP and total, free, and bioavailable vitamin D metabolites in early pregnancy are associated with subsequent neonatal outcomes. In this retrospective analysis of 304 women in early pregnancy (<20 weeks gestation), demographic and anthropometric data were collected and total 25(OH)D (chemiluminescent assay), VDBP (polyclonal enzyme-linked immunosorbent assay (ELISA)) and albumin (automated colorimetry) were measured in bio-banked samples. Free and bioavailable 25(OH)D were calculated using validated formulae. Neonatal outcomes were derived from a medical record database. Higher maternal total and free 25(OH)D concentrations were associated with higher neonatal birthweight (β = 5.05, p = 0.002 and β = 18.06, p = 0.02, respectively), including after adjustment for maternal covariates including age, body mass index (BMI) and ethnicity (all p ≤ 0.04). Higher total 25(OH)D and VDBP concentrations were associated with a lower likelihood of neonatal jaundice (odds ratio [OR] [95%CI] = 0.997 [0.994, 1.000], p = 0.04 and 0.98 [0.96, 0.99], p = 0.03, respectively), but these were attenuated after adjustment for the above maternal covariates (both p = 0.09). Our findings suggest a novel association between free 25(OH)D and neonatal birthweight. Total 25(OH)D concentrations were also associated with birthweight, and both total 25(OH)D and VDBP were associated with jaundice, but the latter were not significant after adjustment. These results suggest a potential link between these metabolites and neonatal outcomes; however, further large-scale prospective studies are warranted.
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12
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Fernando M, Ellery SJ, de Guingand D, Marquina C, Lim S, Harrison CL, Teede HJ, Naderpoor N, Mousa A. Early Pregnancy Vitamin D Binding Protein Is Independently Associated with the Development of Gestational Diabetes: A Retrospective Cohort Study. J Clin Med 2020; 9:E2186. [PMID: 32664376 PMCID: PMC7408791 DOI: 10.3390/jcm9072186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Vitamin D-binding protein (VDBP) has been implicated in several adverse pregnancy outcomes either directly or indirectly via influencing the concentrations of biologically active vitamin D metabolites. However, human studies exploring these metabolites in pregnancy remain sparse. Here, we examine whether VDBP and total, free, and bioavailable 25-hydroxyvitamin D (25(OH)D) metabolites in early pregnancy are associated with subsequent adverse pregnancy outcomes. METHODS We conducted a retrospective analysis of 304 pregnant women in early pregnancy (<20 weeks gestation). The demographic characteristics, anthropometric data, and total 25(OH)D were measured and plasma or serum samples were collected and bio-banked. Using these samples, we measured VDBP (polyclonal ELISA) and albumin (automated colorimetry), and calculated free and bioavailable 25(OH)D using validated formulae. Pregnancy outcomes were derived from scanned medical records. Regression models were used to analyse the relationships between vitamin D metabolites in early pregnancy and subsequent pregnancy outcomes (gestational diabetes mellitus (GDM), pre-eclampsia, preterm birth), with adjustment for predetermined clinically relevant maternal factors including age, body mass index (BMI), and ethnicity. RESULTS Lower VDBP concentrations were associated with higher glucose levels and a greater likelihood of developing GDM at 26-28 weeks gestation (odds ratio [OR] (95% CI) = 0.98 (0.97,0.99), p = 0.015). This finding remained significant after adjustment for maternal covariates including age, BMI, and ethnicity (β = -0.003, p = 0.03). Lower total, free and bioavailable 25(OH)D, but not VDBP, were associated with a shorter length of gestation, but only the relationship with total 25(OH)D remained significant after adjustment for the above maternal covariates (β = 0.02, p = 0.006). CONCLUSIONS This is the first study to examine VDBP, and total, free and bioavailable 25(OH)D in relation to pregnancy outcomes in a well characterised multi-ethnic cohort of pregnant women. Our findings show that VDBP and total 25(OH)D are associated with GDM and length of gestation, respectively; however, further investigations using large-scale prospective studies are needed to confirm our findings.
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Affiliation(s)
- Melinda Fernando
- Monash Centre for Health Research and Implementation (MCHRI) and Centre of Cardiovascular Research and Education in Therapeutics (CCRET), School of Public Health and Preventive Medicine, Monash University, 43-51 Kanooka, Grove, VIC 3168, Australia
| | - Stacey J Ellery
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, 43-51 Kanooka, Grove, VIC 3168, Australia
| | - Deborah de Guingand
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, 43-51 Kanooka, Grove, VIC 3168, Australia
| | - Clara Marquina
- Monash Centre for Health Research and Implementation (MCHRI) and Centre of Cardiovascular Research and Education in Therapeutics (CCRET), School of Public Health and Preventive Medicine, Monash University, 43-51 Kanooka, Grove, VIC 3168, Australia
| | - Siew Lim
- Monash Centre for Health Research and Implementation (MCHRI) and Centre of Cardiovascular Research and Education in Therapeutics (CCRET), School of Public Health and Preventive Medicine, Monash University, 43-51 Kanooka, Grove, VIC 3168, Australia
| | - Cheryce L Harrison
- Monash Centre for Health Research and Implementation (MCHRI) and Centre of Cardiovascular Research and Education in Therapeutics (CCRET), School of Public Health and Preventive Medicine, Monash University, 43-51 Kanooka, Grove, VIC 3168, Australia
| | - Helena J Teede
- Monash Centre for Health Research and Implementation (MCHRI) and Centre of Cardiovascular Research and Education in Therapeutics (CCRET), School of Public Health and Preventive Medicine, Monash University, 43-51 Kanooka, Grove, VIC 3168, Australia
| | - Negar Naderpoor
- Monash Centre for Health Research and Implementation (MCHRI) and Centre of Cardiovascular Research and Education in Therapeutics (CCRET), School of Public Health and Preventive Medicine, Monash University, 43-51 Kanooka, Grove, VIC 3168, Australia
| | - Aya Mousa
- Monash Centre for Health Research and Implementation (MCHRI) and Centre of Cardiovascular Research and Education in Therapeutics (CCRET), School of Public Health and Preventive Medicine, Monash University, 43-51 Kanooka, Grove, VIC 3168, Australia
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13
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Vitamin D Metabolites and Binding Protein Predict Preeclampsia in Women with Type 1 Diabetes. Nutrients 2020; 12:nu12072048. [PMID: 32664257 PMCID: PMC7400952 DOI: 10.3390/nu12072048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/29/2020] [Accepted: 07/08/2020] [Indexed: 11/17/2022] Open
Abstract
The risk for preeclampsia (PE) is enhanced ~4-fold by the presence of maternal type 1 diabetes (T1DM). Vitamin D is essential for healthy pregnancy. We assessed the total, bioavailable, and free concentrations of plasma 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), and vitamin D binding protein (VDBP) at ~12, ~22, and ~32 weeks’ gestation (“Visits” (V) 1, 2, and 3, respectively) in 23 T1DM women who developed PE, 24 who remained normotensive, and 19 non-diabetic, normotensive women (reference controls). 25(OH)D deficiency was more frequent in diabetic than non-diabetic women (69% vs. 22%, p < 0.05), but no measure of 25(OH)D predicted PE. By contrast, higher 1,25(OH)2D concentrations at V2 (total, bioavailable, and free: p < 0.01) and V3 (bioavailable: p < 0.05; free: p < 0.01), lower concentrations of VDBP at V3 (p < 0.05), and elevated ratios of 1,25(OH)2D/VDBP (V2, V3: p < 0.01) and 1,25(OH)2D/25(OH)D (V3, p < 0.05) were all associated with PE, and significance persisted in multivariate analyses. In summary, in women with T1DM, concentrations of 1,25(OH)2D were higher, and VDBP lower, in the second and third trimesters in women who later developed PE than in those who did not. 1,25(OH)2D may serve as a new marker for PE risk and could be implicated in pathogenesis.
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14
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Fang A, Long J, Zhang Y, Liu Z, Li Q, Zhang D, Luo Y, Zhong R, Zhou Z, Xu Y, Xu X, Ling W, Chen M, Zhu H. Serum Bioavailable, Rather Than Total, 25-hydroxyvitamin D Levels Are Associated With Hepatocellular Carcinoma Survival. Hepatology 2020; 72:169-182. [PMID: 31677282 PMCID: PMC7496975 DOI: 10.1002/hep.31013] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 10/27/2019] [Indexed: 12/24/2022]
Abstract
BACKGROUND AND AIMS Free and bioavailable 25-hydroxyvitamin D (25OHD) are emerging measurements of vitamin D status. It remains unclear whether circulating free or bioavailable 25OHD are relevant to hepatocellular carcinoma (HCC) prognosis. Our aim was to test the hypothesis that bioavailable 25OHD may be a better serum biomarker of vitamin D status than total 25OHD on the association with HCC survival. APPROACH AND RESULTS We included 1,031 newly diagnosed, previously untreated patients with HCC from the Guangdong Liver Cancer Cohort enrolled between September 2013 and April 2017. Serum total 25OHD levels were measured using an electrochemiluminescence immunoassay. Serum-free 25OHD levels were measured using a two-step enzyme-linked immunosorbent assay. Bioavailable 25OHD levels were calculated from measured free 25OHD and albumin using a previously validated equation. Primary outcomes were liver cancer-specific (LCSS) and overall survival (OS). Cox proportional hazards models were performed to calculate the multivariable hazard ratios (HRs) and 95% confidence intervals (CIs). During a median follow-up of 726 days, 430 patients had deceased, including 393 deaths from HCC. In multivariable analyses, higher bioavailable 25OHD levels were significantly associated with better survival, independent of nonclinical and clinical prognostic factors including serum C-reactive protein, Barcelona Clinic Liver Cancer stage, and cancer treatment. The multivariable-adjusted HRs in the highest versus lowest quartile of bioavailable 25OHD levels were 0.69 (95% CI: 0.51, 0.93; P for trend = 0.014) for LCSS and 0.71 (95% CI: 0.53, 0.94; P for trend = 0.013) for OS. In contrast, neither total nor free 25OHD levels were associated with LCSS or OS. CONCLUSIONS Higher bioavailable, rather than total, 25OHD levels were independently associated with improved survival in a population-based HCC cohort, suggesting a potential utility of bioavailable 25OHD in HCC prognosis.
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Affiliation(s)
- Ai‐Ping Fang
- Department of NutritionSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina,Guangdong Provincial Key Laboratory of Food, Nutrition and HealthSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina
| | - Jing‐An Long
- Department of NutritionSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina
| | - Yao‐Jun Zhang
- Department of Hepatobiliary OncologySun Yat‐sen University Cancer CenterGuangzhouChina,State Key Laboratory of Oncology in South ChinaSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Zhao‐Yan Liu
- Department of NutritionSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina
| | - Qi‐Jiong Li
- Department of Hepatobiliary OncologySun Yat‐sen University Cancer CenterGuangzhouChina,State Key Laboratory of Oncology in South ChinaSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Dao‐Ming Zhang
- Department of NutritionSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina
| | - Yun Luo
- Department of NutritionSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina
| | - Rong‐Huan Zhong
- Department of NutritionSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina
| | - Zhong‐Guo Zhou
- Department of Hepatobiliary OncologySun Yat‐sen University Cancer CenterGuangzhouChina,State Key Laboratory of Oncology in South ChinaSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Yan‐Jun Xu
- Department of Chronic Noncommunicable Disease Prevention and ControlGuangdong Provincial Center for Disease Control and PreventionGuangzhouChina
| | - Xiao‐Jun Xu
- Department of Chronic Noncommunicable Disease Prevention and ControlGuangdong Provincial Center for Disease Control and PreventionGuangzhouChina
| | - Wen‐Hua Ling
- Department of NutritionSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina,Guangdong Provincial Key Laboratory of Food, Nutrition and HealthSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina
| | - Min‐Shan Chen
- Department of Hepatobiliary OncologySun Yat‐sen University Cancer CenterGuangzhouChina,State Key Laboratory of Oncology in South ChinaSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Hui‐Lian Zhu
- Department of NutritionSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina,Guangdong Provincial Key Laboratory of Food, Nutrition and HealthSchool of Public HealthSun Yat‐sen UniversityGuangzhouChina
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15
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Makris K, Sempos C, Cavalier E. The measurement of vitamin D metabolites part II-the measurement of the various vitamin D metabolites. Hormones (Athens) 2020; 19:97-107. [PMID: 32221839 DOI: 10.1007/s42000-020-00188-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 03/10/2020] [Indexed: 12/18/2022]
Abstract
Today, the possibility exists to measure a number of different vitamin D metabolites with accurate and precise methods. The most abundant vitamin D metabolite, 25(OH)D, is considered the best marker for estimating vitamin D status and is therefore the most commonly measured in clinical practice. There is no consensus on the added value of measuring other metabolites beyond 25-hydroxyvitamin D, although, in some special clinical scenarios and complicated cases, these metabolites may provide just the information needed for an accurate diagnosis. The problem this review addresses is which metabolite to measure and when and how to measure it.
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Affiliation(s)
- Konstantinos Makris
- Clinical Biochemistry Department, KAT General Hospital, 2 Nikis Str., 14561, Kifissia, Greece.
| | - Christopher Sempos
- Vitamin D Standardization Program (VDSP), Havre de Grace, MD, 21078, USA
| | - Etienne Cavalier
- Department of Clinical Chemistry, University of Liege, CHU de Liege, Belgium
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16
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Hurst EA, Homer NZ, Denham SG, MacFarlane E, Campbell S, Boswinkel M, Mellanby RJ. Development and application of a LC-MS/MS assay for simultaneous analysis of 25-hydroxyvitamin-D and 3-epi-25-hydroxyvitamin-D metabolites in canine serum. J Steroid Biochem Mol Biol 2020; 199:105598. [PMID: 31958632 DOI: 10.1016/j.jsbmb.2020.105598] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 12/25/2022]
Abstract
Hypovitaminosis D and hypervitaminosis D are well recognised disorders in dogs. Hypovitaminosis D can occur following consumption of a diet inadequately supplemented with vitamin D or as a sequelae of severe intestinal disease. Hypervitaminosis D may occur as a result of consuming proprietary dog foods over-supplemented with vitamin D or through ingestion of vitamin D containing medicinal products or rodenticides. Consequently, there is a clear need to establish a methodology that can accurately quantify vitamin D metabolites across a broad dynamic range in dogs. The existence of C3-epimers of vitamin D metabolites has yet to be elucidated in dogs, yet are known to interfere with the analysis of vitamin D and have unknown biological activity in other species. Here, we describe the development and validation of a sensitive, specific and robust analytical liquid chromatography tandem mass spectrometry (LC-MS/MS) assay capable of separating and accurately measuring 25-hydroxyvitamin-D2/3 (25(OH)D2/3) and 3-epi-25-hydroxyvitamin-D2/3 (3-epi-25(OH)D2/3). We describe a simplified workflow utilising supported liquid extraction (SLE) without derivatization that provides good linearity (mean r > 0.996) and accuracy across a broad dynamic range of 4-500 nmol/L for D3 metabolites and 7.8-500 nmol/L for D2 metabolites. Upon application of this assay to 117 canine serum samples, 25(OH)D3 was detectable in all samples with a median concentration of 82.1 nmol/L (inter-quartile range (IQR) 59.7-101.8 nmol/L). 3-epi-25(OH)D3 could be detected in 87.2 % of the study population, with a median concentration of 5.2 nmol/L (2.4-8.1 nmol/L). However, 3-epi-25(OH)D3 was quantified below the LLOQ in 40.2 % of these samples. 3-epi-25(OH)D3 contributed on average 6.3 % to 25(OH)D3 status (contribution ranges from 0 to 23.8%) and a positive correlation was detected between 25(OH)D3 and 3-epi-25(OH)D3 concentrations. Free 25(OH)D was also measured using an immunoassay with a median concentration of 15.2 pmol/L (12.5-23.2 pmol/L), and this metabolite was also positively correlated to both 3-epi-25(OH)D3 and 25(OH)D3 concentrations. D2 metabolites were not detected in canine serum as expected. Vitamin D metabolite concentrations were variable between individuals, and research into the causes of this variation should include factors such as breed, age, sex and neuter status to determine the impact of genetic and hormonal factors. Given the clinical importance of vitamin D in dogs, and the immense potential for utilising this species as a model for human disease, further elucidation of the vitamin D pathway in this species would provide immense clinical and research benefit.
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Affiliation(s)
- Emma A Hurst
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, Edinburgh, Scotland, EH25 9RG, United Kingdom; Mass Spectrometry Core, Edinburgh Clinical Research Facility, Queen's Medical Research Institute, The University of Edinburgh, Little France Crescent, Edinburgh, Scotland, EH16 4TJ, United Kingdom.
| | - Natalie Z Homer
- Mass Spectrometry Core, Edinburgh Clinical Research Facility, Queen's Medical Research Institute, The University of Edinburgh, Little France Crescent, Edinburgh, Scotland, EH16 4TJ, United Kingdom.
| | - Scott G Denham
- Mass Spectrometry Core, Edinburgh Clinical Research Facility, Queen's Medical Research Institute, The University of Edinburgh, Little France Crescent, Edinburgh, Scotland, EH16 4TJ, United Kingdom.
| | - Emma MacFarlane
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, Edinburgh, Scotland, EH25 9RG, United Kingdom.
| | - Susan Campbell
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, Edinburgh, Scotland, EH25 9RG, United Kingdom.
| | - Maaike Boswinkel
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, Edinburgh, Scotland, EH25 9RG, United Kingdom.
| | - Richard J Mellanby
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, Edinburgh, Scotland, EH25 9RG, United Kingdom.
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17
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Tsuprykov O, Buse C, Skoblo R, Hocher B. Comparison of free and total 25-hydroxyvitamin D in normal human pregnancy. J Steroid Biochem Mol Biol 2019; 190:29-36. [PMID: 30904637 DOI: 10.1016/j.jsbmb.2019.03.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 03/05/2019] [Accepted: 03/11/2019] [Indexed: 12/25/2022]
Abstract
Vitamin D status correct monitoring during pregnancy is critically important for both maternal and fetal health. 25-Hydroxyvitamin D (25(OH)D) - a prohormone of a biologically active 1,25-dihydroxyvitamin D (1,25(OH)2D), despite the lack of biological activity, during the past decades has been routinely used as a main biomarker characterizing vitamin D status. About 85% of 25(OH)D in the bloodstream is bound to its specific carrier - vitamin D-binding protein (DBP), the remaining 15% are loosely bound to albumin, and only less than 0.1% are free in the circulation ("free 25(OH)D"). Total 25(OH)D is the sum of DBP-bound, albumin-bound and free 25(OH)D. According to a "free hormone hypothesis", only free 25(OH)D is able to induce a biological effect. Normal pregnancy is characterized by elevated serum DBP levels, and due to this fact the diagnostic strength of serum total 25(OH)D has been questioned. Free 25(OH)D might be a better characteristic of vitamin D status in this settings. We aimed to compare the diagnostic strength of a routine total 25(OH)D with directly measured free 25(OH)D in normal pregnancy by comparing the association strength between free and total 25(OH)D with biomarkers of bone health (PTH, calcium, bone-specific alkaline phosphatase (BSAP)), lipid metabolism (adiponectin, LDL, HDL), kidney function (urea), endocrine parameters (T4, T3, TSH), and group B water-soluble vitamins. The study was conducted in 368 healthy white pregnant women - residents of north-east Germany. Free 25(OH)D showed an overall better associations with gestational age, markers of bone metabolism (calcium (rho = 0.141, p = 0.007 with free 25(OH)D; rho = 0.060, p = 0.251 with total 25(OH)D) and BSAP (rho = -0.203, p < 0.001 with free 25(OH)D; rho = -0.108, p = 0.038 with total 25(OH)D), lipid metabolism parameters (adiponectin (rho = 0.142, p = 0.008 with free 25(OH)D; rho = 0.054, p = 0.307 with total 25(OH)D), LDL cholesterol (rho = -0.191, p < 0.001 with free 25(OH)D; rho = 0.033, p = 0.539 with total 25(OH)D)) and a kidney function marker (urea (rho = 0.114, p = 0.032 with free 25(OH)D; rho = 0.008, p = 0.887 with total 25(OH)D)) than total 25(OH)D. In conclusion, the current study revealed that free 25(OH)D is a more precise determinant of the vitamin D status during normal human pregnancy than total 25(OH)D. In the settings of normal pregnancy, free 25(OH)D revealed better associations with markers of bone metabolism (calcium, BSAP), lipid metabolism (adiponectin, LDL cholesterol, LDL/HDL ratio) and kidney function (urea) than total 25(OH)D.
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Affiliation(s)
- Oleg Tsuprykov
- Institute for Laboratory Medicine, IFLB, Berlin, Germany
| | | | - Roman Skoblo
- Institute for Laboratory Medicine, IFLB, Berlin, Germany
| | - Berthold Hocher
- LADR GmbH, MVZ Neuruppin, Neuruppin, Germany; Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology), University Medical Centre Mannheim, University of Heidelberg, Heidelberg, Germany; Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China; Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha, Hunan, China.
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18
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Best CM, Pressman EK, Queenan RA, Cooper E, O'Brien KO. Longitudinal changes in serum vitamin D binding protein and free 25-hydroxyvitamin D in a multiracial cohort of pregnant adolescents. J Steroid Biochem Mol Biol 2019; 186:79-88. [PMID: 30278215 PMCID: PMC6611677 DOI: 10.1016/j.jsbmb.2018.09.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/30/2018] [Accepted: 09/28/2018] [Indexed: 10/28/2022]
Abstract
Serum free 25-hydroxyvitamin D (25(OH)D) rather than total 25(OH)D may better indicate vitamin D status during pregnancy given the pregnancy-associated increase in serum vitamin D binding protein (DBP) concentration. Our aims were to assess changes in DBP and free 25(OH)D across gestation and to determine whether free compared with total 25(OH)D more strongly correlates with markers of vitamin D and calcium metabolism during pregnancy. This ancillary study included 58 pregnant adolescents (53% African American, 47% White) who completed a vitamin D3 supplementation study in Rochester, NY. Blood was collected at entry, mid-study, and delivery (median 17, 29, and 40 weeks' gestation). Mixed-effects regression was used to test for differences in DBP, directly measured free 25(OH)D, and other serum markers by study visit and race. Free and total 25(OH)D were evaluated in relation to serum PTH, 1,25(OH)2D, 24,25(OH)2D, and calcium. The mean DBP concentration was above nonpregnant reference values at entry and increased across gestation (P < 0.0001). Total 25(OH)D explained most of the variance in free 25(OH)D (r ≥ 0.67; P < 0.0001). Holding total 25(OH)D constant, each 100 mg/L increase in DBP was associated with a 0.4 pg/mL decrease in free 25(OH)D (P < 0.01). The percent free 25(OH)D was inversely related to both DBP and total 25(OH)D at each visit. Regardless of race or visit, total 25(OH)D was a stronger correlate of PTH, 1,25(OH)2D, and 24,25(OH)2D, and neither total nor free 25(OH)D was related to serum calcium. African Americans had lower total 25(OH)D (P < 0.0001), but free 25(OH)D did not significantly differ by race (P = 0.2). In pregnant adolescents, DBP concentration was elevated and inversely associated with percent free 25(OH)D, but measured free 25(OH)D provided no advantage over total 25(OH)D as a predictor of PTH, 1,25(OH)2D, 24,25(OH)2D, or calcium. The clinical relevance of the small racial difference in percent free 25(OH)D requires further investigation.
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Affiliation(s)
- Cora M Best
- Division of Nutritional Sciences, Cornell University, 244 Garden Avenue, Ithaca, NY 14853, USA
| | - Eva K Pressman
- Department of Obstetrics and Gynecology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Ruth Anne Queenan
- Department of Obstetrics and Gynecology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Elizabeth Cooper
- Department of Obstetrics and Gynecology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Kimberly O O'Brien
- Division of Nutritional Sciences, Cornell University, 244 Garden Avenue, Ithaca, NY 14853, USA.
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19
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Kim HY, Kim JH, Jung MH, Cho IA, Kim Y, Cho MC. Clinical Usefulness of Bioavailable Vitamin D and Impact of GC Genotyping on the Determination of Bioavailable Vitamin D in a Korean Population. Int J Endocrinol 2019; 2019:9120467. [PMID: 30774661 PMCID: PMC6350553 DOI: 10.1155/2019/9120467] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 10/22/2018] [Accepted: 11/29/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Bioavailable 25-hydroxy vitamin D (25(OH)D) has been suggested for the accurate determination of vitamin D status. The purpose of this study was to determine the utility of bioavailable 25(OH)D in assessing vitamin D status when vitamin D-binding protein (VDBP) was significantly altered by pregnancy and liver cirrhosis (LC). The role of genotyping of GC, a gene encoding VDBP, in the determination of bioavailable 25(OH)D concentration in a Korean population was also evaluated. METHODS This prospective study enrolled a total of 136 subjects (53 healthy controls, 45 patients with LC, and 38 pregnant women) from 2017 to 2018. The concentrations of total 25(OH)D and VDBP were measured, and bioavailable 25(OH)D concentrations were calculated. GC genotyping was performed to determine rs4588 and rs7041 polymorphisms. Clinical and laboratory data were compared among the three groups of subjects. RESULTS Median VDBP and total 25(OH)D concentrations were 165.2 μg/ml and 18.5 ng/ml in healthy controls, 76.9 μg/ml and 10.5 ng/ml in patients with LC, and 368.9 μg/ml and 17.7 ng/ml in pregnant women, respectively. Compared with controls, patients diagnosed with LC had significantly lower VDBP and total 25(OH)D concentrations (all P < 0.001) while pregnant women had significantly higher VDBP concentrations (P < 0.001). Although total 25(OH)D concentrations in pregnant women were similar to those in controls (P = 0.394), their bioavailable 25(OH)D concentrations were significantly lower (1.2 vs. 3.0 ng/ml; P < 0.001). Among all the three groups combined, the genotype-specific bioavailable 25(OH)D and the genotype-independent bioavailable 25(OH)D concentrations did not differ significantly (P = 0.299). CONCLUSIONS Our study has demonstrated that bioavailable 25(OH)D concentration reflects vitamin D status more accurately than the total 25(OH)D concentration, especially in pregnant women. In addition, GC genotyping did not significantly affect bioavailable 25(OH)D concentration. Therefore, if VDBP concentration is significantly altered, the measurement of bioavailable 25(OH)D concentration might facilitate the accurate determination of vitamin D status. However, GC genotyping might be unnecessary.
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Affiliation(s)
- Hyun-Young Kim
- Department of Laboratory Medicine, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea
| | - Jin Hyun Kim
- Biomedical Research Institute, Gyeongsang National University Hospital, Jinju 52727, Republic of Korea
- Institute of Health Science, Gyeongsang National University, Jinju 52727, Republic of Korea
| | - Myeong Hee Jung
- Biomedical Research Institute, Gyeongsang National University Hospital, Jinju 52727, Republic of Korea
| | - In Ae Cho
- Department of Obstetrics and Gynecology, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea
| | - Youngjin Kim
- Department of Laboratory Medicine, Kyung Hee University Hospital, Kyung Hee University School of Medicine, Seoul 02447, Republic of Korea
| | - Min-Chul Cho
- Department of Laboratory Medicine, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea
- Institute of Health Science, Gyeongsang National University, Jinju 52727, Republic of Korea
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Bikle DD, Schwartz J. Vitamin D Binding Protein, Total and Free Vitamin D Levels in Different Physiological and Pathophysiological Conditions. Front Endocrinol (Lausanne) 2019; 10:317. [PMID: 31191450 PMCID: PMC6546814 DOI: 10.3389/fendo.2019.00317] [Citation(s) in RCA: 227] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 05/01/2019] [Indexed: 12/19/2022] Open
Abstract
This review focuses on the biologic importance of the vitamin D binding protein (DBP) with emphasis on its regulation of total and free vitamin D metabolite levels in various clinical conditions. Nearly all DBP is produced in the liver, where its regulation is influenced by estrogen, glucocorticoids and inflammatory cytokines but not by vitamin D itself. DBP is the most polymorphic protein known, and different DBP alleles can have substantial impact on its biologic functions. The three most common alleles-Gc1f, Gc1s, Gc2-differ in their affinity with the vitamin D metabolites and have been variably associated with a number of clinical conditions. Although DBP has a number of biologic functions independent of vitamin D, its major biologic function is that of regulating circulating free and total levels of vitamin D metabolites. 25 hydroxyvitamin D (25(OH)D) is the best studied form of vitamin D as it provides the best measure of vitamin D status. In a normal non-pregnant individual, approximately 0.03% of 25(OH)D is free; 85% is bound to DBP, 15% is bound to albumin. The free hormone hypothesis postulates that only free 25(OH)D can enter cells. This hypothesis is supported by the observation that mice lacking DBP, and therefore with essentially undetectable 25(OH)D levels, do not show signs of vitamin D deficiency unless put on a vitamin D deficient diet. Similar observations have recently been described in a family with a DBP mutation. This hypothesis also applies to other protein bound lipophilic hormones including glucocorticoids, sex steroids, and thyroid hormone. However, tissues expressing the megalin/cubilin complex, such as the kidney, have the capability of taking up 25(OH)D still bound to DBP, but most tissues rely on the free level. Attempts to calculate the free level using affinity constants generated in a normal individual along with measurement of DBP and total 25(OH)D have not accurately reflected directly measured free levels in a number of clinical conditions. In this review, we examine the impact of different clinical conditions as well as different DBP alleles on the relationship between total and free 25(OH)D, using only data in which the free 25(OH)D level was directly measured. The major conclusion is that a number of clinical conditions alter this relationship, raising the question whether measuring just total 25(OH)D might be misleading regarding the assessment of vitamin D status, and such assessment might be improved by measuring free 25(OH)D instead of or in addition to total 25(OH)D.
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Affiliation(s)
- Daniel David Bikle
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
- Endocrine Research Unit, San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States
- *Correspondence: Daniel David Bikle
| | - Janice Schwartz
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
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Jorde R. The Role of Vitamin D Binding Protein, Total and Free 25-Hydroxyvitamin D in Diabetes. Front Endocrinol (Lausanne) 2019; 10:79. [PMID: 30837950 PMCID: PMC6389604 DOI: 10.3389/fendo.2019.00079] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 01/30/2019] [Indexed: 12/16/2022] Open
Abstract
Vitamin D is important for bone health, but may also have extra-skeletal effects. Vitamin D and its binding protein DBP have immunological effects and may therefore be important in the development of type 1 diabetes (T1DM), and low serum levels of 25-hydroxyvitamin D (25(OH)D) are associated with later development of type 2 diabetes (T2DM). However, it has so far been difficult to convincingly show an effect of vitamin D supplementation on prevention or treatment of diabetes. The serum level of 25(OH)D has traditionally been used as a marker of a subject's vitamin D status. This measurement includes both 25(OH)D bound to DBP and albumin as well as the free from of 25(OH)D. However, according to the free hormone hypothesis, the free form is the biologically active. Previously the free form of 25(OH)D had to be calculated based on measurements of 25(OH)D, DBP, and albumin, but recently a method for direct measurement of free 25(OH)D has become commercially available. This is important in clinical conditions where the amount of DBP is affected, and has caused a renewed interest in which vitamin D metabolite to measure in clinical situations. In the present review the relations between DBP, total and free 25(OH)D in T1DM and T2DM are described.
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Affiliation(s)
- Rolf Jorde
- Tromsø Endocrine Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
- Division of Internal Medicine, University Hospital of North Norway, Tromsø, Norway
- *Correspondence: Rolf Jorde
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Ruiz JL, François A. Primeros registros precisos de <em>Trox strandi</em> Balthasar, 1936 (Coleoptera: Trogidae) en Marruecos y observaciones sobre su hábitat y variabilidad morfológica. GRAELLSIA 2018. [DOI: 10.3989/graellsia.2018.v74.214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Trox strandi es una especie rara cuyo estatus taxonómico ha sido controvertido y hasta el momento únicamente se conoce de la localidad tipo, Sidi-bel-Abbes, en el noroeste de Argelia. No obstante, ha sido señalada genéricamente de Libia, Túnez y Marruecos, pero sin que se aporten localidades concretas o material adicional. En el transcurso de diversos muestreos en el sureste de Marruecos durante los últimos años, hemos hallado dos ejemplares atribuibles a esta especie en otras tantas localidades (Tameslemt, en las estribaciones nororientales del Alto Atlas, y Ksabi, en el tramo alto del río Muluya), que constituyen los primeros registros precisos para este país. Estas localidades se sitúan en regiones con bioclima árido y semiárido y escasa cobertura vegetal. Se aportan datos sobre el hábitat, caracteres diagnósticos y variabilidad morfológica de la especie.
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Schwartz JB, Gallagher JC, Jorde R, Berg V, Walsh J, Eastell R, Evans AL, Bowles S, Naylor KE, Jones KS, Schoenmakers I, Holick M, Orwoll E, Nielson C, Kaufmann M, Jones G, Bouillon R, Lai J, Verotta D, Bikle D. Determination of Free 25(OH)D Concentrations and Their Relationships to Total 25(OH)D in Multiple Clinical Populations. J Clin Endocrinol Metab 2018; 103:3278-3288. [PMID: 29955795 PMCID: PMC6126881 DOI: 10.1210/jc.2018-00295] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/21/2018] [Indexed: 11/19/2022]
Abstract
Context The optimal measure of vitamin D status is unknown. Objective To directly measure circulating free 25-hydroxyvitamin D [25(OH)D] concentrations and relationships to total 25(OH)D in a clinically diverse sample of humans. Design Cross-sectional analysis. Setting Seven academic sites. Patients A total of 1661 adults: healthy (n = 279), prediabetic (n = 479), outpatients (n = 714), cirrhotic (n = 90), pregnant (n = 20), nursing home resident (n = 79). Interventions Merge research data on circulating free 25(OH)D (directly-measured immunoassay), total 25(OH)D (liquid chromatography/tandem mass spectrometry), D-binding protein [DBP; by radial (polyclonal) immunodiffusion assay], albumin, creatinine, intact parathyroid hormone, and DBP haplotype. Main outcome measures Distribution of free 25(OH)D (ANOVA with Bonferroni correction for post hoc comparisons) and relationships between free and total 25(OH)D (mixed-effects modeling incorporating clinical condition, DBP haplotype with sex, race, estimated glomerular filtration rate (eGFR), body mass index (BMI), and other covariates). Results Free 25(OH)D was 4.7 ± 1.8 pg/mL (mean ± SD) in healthy persons and 4.3 ± 1.9 pg/mL in outpatients, with levels of 0.5 to 8.1 pg/mL and 0.9 to 8.1 pg/mL encompassing 95% of healthy persons and outpatients, respectively. Free 25(OH)D was higher in patients with cirrhosis (7.1 ± 3.0 pg/mL; P < 0.0033) and nursing home residents (7.9 ± 2.1 pg/mL; P < 0.0033) than in other groups and differed between whites and blacks (P < 0.0033) and between DBP haplotypes (P < 0.0001). Mixed-effects modeling of relationships between free and total 25(OH)D identified clinical conditions (patients with cirrhosis > nursing home residents > patients with prediabetes > outpatients > pregnant women) and BMI (lesser effect) as covariates affecting relationships but not eGFR, sex, race, or DBP haplotype. Conclusions Total 25(OH)D, health condition, race, and DBP haplotype affected free 25(OH)D, but only health conditions and BMI affected relationships between total and free 25(OH)D. Clinical importance of free 25(OH)D needs to be established in studies assessing outcomes.
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Affiliation(s)
- Janice B Schwartz
- Department of Medicine, University of California, San Francisco, California
| | | | - Rolf Jorde
- Tromso Endocrine Research Group, UiT the Arctic University of Norway, Tromsø, Norway
- Division of Internal Medicine, University Hospital of North Norway, Tromsø, Norway
| | - Vivian Berg
- Division of Internal Medicine, University Hospital of North Norway, Tromsø, Norway
| | - Jennifer Walsh
- Mellanby Centre for Bone Research, University of Sheffield, Sheffield, United Kingdom
| | - Richard Eastell
- Mellanby Centre for Bone Research, University of Sheffield, Sheffield, United Kingdom
| | - Amy L Evans
- Mellanby Centre for Bone Research, University of Sheffield, Sheffield, United Kingdom
| | - Simon Bowles
- Mellanby Centre for Bone Research, University of Sheffield, Sheffield, United Kingdom
| | - Kim E Naylor
- Mellanby Centre for Bone Research, University of Sheffield, Sheffield, United Kingdom
| | - Kerry S Jones
- MRC Elsie Widdowson Laboratory, Cambridge, United Kingdom
| | - Inez Schoenmakers
- MRC Elsie Widdowson Laboratory, Cambridge, United Kingdom
- Department of Medicine, Norwich Medical School, Faculty of Medicine and Health Sciences, Norwich, United Kingdom
- University of East Anglia, Norwich, United Kingdom
| | - Michael Holick
- Boston University School of Medicine, Boston, Massachusetts
| | - Eric Orwoll
- Oregon Health and Science University, Portland, Oregon
| | | | | | | | | | - Jennifer Lai
- Department of Medicine, University of California, San Francisco, California
| | - Davide Verotta
- Departments of Bioengineering and Therapeutic Sciences and Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California
| | - Daniel Bikle
- Department of Medicine, University of California, San Francisco, California
- Department of Dermatology, University of California, San Francisco, San Francisco, California
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Lopez-Molina M, Santillan C, Murillo M, Valls A, Bosch L, Bel J, Granada ML. Measured free 25-hydroxyvitamin D in healthy children and relationship to total 25-hydroxyvitamin D, calculated free 25-hydroxyvitamin D and vitamin D binding protein. Clin Biochem 2018; 61:23-27. [PMID: 30130523 DOI: 10.1016/j.clinbiochem.2018.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/03/2018] [Accepted: 08/14/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND vitamin D deficiency in children is still a global health problem. Measuring free 25-hydroxyvitamin D concentrations could provide a better estimate of the vitamin D status than total 25-hydroxyvitamin D (25(OH)D) levels. OBJECTIVE To assess the relationship between measured free vitamin D (m-f25(OH)D) and calculated free 25(OH)D (c-f25(OH)D), total 25(OH)D, intact parathyroid hormone (iPTH) and other markers of phosphocalcic metabolism. To establish serum m-f25(OH)D concentrations corresponding to a total 25(OH)D > 50 nmol/L which is accepted as vitamin D-sufficiency status in children. DESIGN Prospective cohort study. SETTING January and February 2017 in a Mediterranean population. PATIENTS healthy children. MEASUREMENTS m-f25(OH)D and vitamin D binding protein (VDBP) by ELISA. Free 25(OH)D was calculated using the formula described by Bikle. RESULTS m-f25(OH)D directly correlated with total 25(OH)D (r:0.804,p < .001), serum calcium (r:0.26,p:0.035), and c-f25(OH)D (r:0.553,p:0.016); and inversely with iPTH (r:-0.374, p:0.002), alkaline phosphatase (r:-0.28, p:0.026), and age (r:-0.289, p:0.018). Total 25(OH)D correlated with the same parameters as m-f25(OH)D except for serum calcium. However, c-f25(OH)D correlated only with total 25(OH)D and VDBP, both included in the calculation formula. Multiple regression analysis showed that m-f25(OH)D variations were independently explained by calcium (β:0.156, p:0.026) and total 25(OH)D (β:0.043, p < .001). The optimal m-f25(OH)D cut-off for discriminating between insufficient and sufficient total 25(OH)D was >9.8 pmol/L (Area Under Curve (AUC): 0.897 (95% confidence interval (CI): (0.798-0.958); p < .001; sensitivity:72.7% (95%CI: 49.8-89.3); specificity: 95.5% (95%CI: 84.5-99.4)). CONCLUSIONS Directly measured free vitamin D correlated better with markers of phosphocalcic metabolism than total 25(OH)D and c-f25(OH)D in a population of healthy children.
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Affiliation(s)
- Maria Lopez-Molina
- Clinical Analysis and Biochemistry Department, Germans Trias i Pujol University Hospital, Badalona, Universitat Autònoma Barcelona, Spain.
| | - Cecilia Santillan
- Paediatrics Department, Germans Trias i Pujol University Hospital, Badalona, Universitat Autònoma Barcelona, Spain
| | - Marta Murillo
- Paediatrics Department, Germans Trias i Pujol University Hospital, Badalona, Universitat Autònoma Barcelona, Spain
| | - Aina Valls
- Paediatrics Department, Germans Trias i Pujol University Hospital, Badalona, Universitat Autònoma Barcelona, Spain
| | - Laura Bosch
- Paediatrics Department, Germans Trias i Pujol University Hospital, Badalona, Universitat Autònoma Barcelona, Spain
| | - Joan Bel
- Paediatrics Department, Germans Trias i Pujol University Hospital, Badalona, Universitat Autònoma Barcelona, Spain
| | - María Luisa Granada
- Clinical Analysis and Biochemistry Department, Germans Trias i Pujol University Hospital, Badalona, Universitat Autònoma Barcelona, Spain
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Tsuprykov O, Buse C, Skoblo R, Haq A, Hocher B. Reference intervals for measured and calculated free 25-hydroxyvitamin D in normal pregnancy. J Steroid Biochem Mol Biol 2018; 181:80-87. [PMID: 29567112 DOI: 10.1016/j.jsbmb.2018.03.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 12/29/2022]
Abstract
The determination of free 25-hydroxyvitamin D (25(OH)D) as compared to the analysis of total 25-hydroxyvitamin D might reflect better the vitamin D status during pregnancy, since vitamin D-binding protein (DBP) concentrations increase throughout pregnancy and the vast majority of 25(OH)D is tightly bound to DBP thus strongly influencing total 25(OH)D. The concentration of the biologically active free 25(OH)D - on the other hand - is much less dependent on the DBP concentrations. The study was conducted in May-June 2016 in 368 Caucasian pregnant healthy women - residents of Northeastern Germany. Free 25(OH)D was either measured directly by commercial ELISA kit or assessed by calculation via total 25(OH)D, DBP, and albumin serum concentrations. Regardless of the detection method, free 25(OH)D lowers in the 3rd trimester comparing to the 1st trimester (by 12% and 21%, p < 0.05 and p < 0.001, for measured and calculated free 25(OH)D, respectively), whereas total 25(OH)D was not decreased in late pregnancy. DBP rises with gestational age. Total 25(OH)D was not correlated with serum calcium (p = 0.251), whereas free 25(OH)D was significantly (p = 0.007 for measured free 25(OH)D and p < 0.001 for calculated free 25(OH)D) positively correlated with calcium. All 25(OH)D isoforms were significantly negatively correlated with bone-specific alkaline phosphatase (BSAP), however the correlation strength was the lowest with total 25(OH)D (rho = -0.108, p = 0.038), whereas both measured and calculated free 25(OH)D revealed better associations with BSAP (rho = -0.203 and rho = -0.211 for measured and calculated free 25(OH)D, respectively, p < 0.001 for both). We established pregnancy trimester-specific reference intervals for free measured and calculated 25(OH)D and DBP. Both measured and calculated free 25(OH)D showed better correlations with parameters of the endocrine vitamin D system (calcium and BSAP). Both ways of measuring free 25(OH)D in pregnant women are suitable as novel laboratory parameter for vitamin D status monitoring during human pregnancy and might replace in the future the routine total 25(OH)D assessment.
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Affiliation(s)
- Oleg Tsuprykov
- Institute of Nutritional Sciences, University of Potsdam, Potsdam, Germany; Institute for Laboratory Medicine, IFLB, Berlin, Germany
| | - Claudia Buse
- Institute for Laboratory Medicine, IFLB, Berlin, Germany
| | - Roman Skoblo
- Institute for Laboratory Medicine, IFLB, Berlin, Germany
| | - Afrozul Haq
- Department of Food Technology, School of Interdisciplinary Sciences, Jamaia Hamdard University, New Delhi, India
| | - Berthold Hocher
- Institute of Nutritional Sciences, University of Potsdam, Potsdam, Germany; Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China.
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von Websky K, Hasan AA, Reichetzeder C, Tsuprykov O, Hocher B. Impact of vitamin D on pregnancy-related disorders and on offspring outcome. J Steroid Biochem Mol Biol 2018; 180:51-64. [PMID: 29169993 DOI: 10.1016/j.jsbmb.2017.11.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 11/15/2017] [Accepted: 11/20/2017] [Indexed: 12/16/2022]
Abstract
Observational studies from all over the world continue to find high prevalence rates of vitamin D insufficiency and deficiency in many populations, including pregnant women. Beyond its classical function as a regulator of calcium and phosphate metabolism, vitamin D elicits numerous effects in the human body. Current evidence highlights a vital role of vitamin D in mammalian gestation. During pregnancy, adaptations in maternal vitamin D metabolism lead to a physiologic increase of vitamin D levels, mainly because of an increased renal production, although other potential sources like the placenta are being discussed. A sufficient supply of mother and child with calcium and vitamin D during pregnancy ensures a healthy bone development of the fetus, whereas lack of either of these nutrients can lead to the development of rickets in the child. Moreover, vitamin D insufficiency during pregnancy has consistently been associated with adverse maternal and neonatal pregnancy outcomes. In multitudinous studies, low maternal vitamin D status was associated with a higher risk for preeclampsia, gestational diabetes mellitus and other gestational diseases. Likewise, several negative consequences for the fetus have been reported, including fetal growth restriction, increased risk of preterm birth and a changed susceptibility for later-life diseases. However, study results are diverging and causality has not been proven so far. Meta-analyses on the relationship between maternal vitamin D status and pregnancy outcomes revealed a wide heterogeneity of studied populations and the applied methodology in vitamin D assessment. Until today, clinical guidelines for supplementation cannot be based on high-quality evidence and it is not clear if the required intake for pregnant women differs from non-pregnant women. Long-term safety data of vitamin D supplementation in pregnant women has not been established and overdosing of vitamin D might have unfavorable effects, especially in mothers and newborns with mutations of genes involved in vitamin D metabolism. Reliable data from large observational and interventional randomized control trials are urgently needed as a basis for any detailed and safe recommendations for supplementation in the general population and, most importantly, in pregnant women. This is of utmost importance, as ensuring a sufficient vitamin D-supply of mother and child implies a great potential for the prevention of birth complications and development of diseases.
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Affiliation(s)
- Karoline von Websky
- Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany; Center for Cardiovascular Research, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ahmed Abdallah Hasan
- Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany; Department of Biochemistry, Faculty of Pharmacy, Zagazig University, Egypt
| | - Christoph Reichetzeder
- Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany; Center for Cardiovascular Research, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Oleg Tsuprykov
- Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany; Institute for Laboratory Medicine, IFLB, Berlin, Germany
| | - Berthold Hocher
- Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany; Institute for Laboratory Medicine, IFLB, Berlin, Germany; Department of Basic Medicine, Medical College of Hunan Normal University, Changsha, China.
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Tsuprykov O, Chen X, Hocher CF, Skoblo R, Hocher B. Why should we measure free 25(OH) vitamin D? J Steroid Biochem Mol Biol 2018; 180:87-104. [PMID: 29217467 DOI: 10.1016/j.jsbmb.2017.11.014] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 11/30/2017] [Accepted: 11/30/2017] [Indexed: 11/21/2022]
Abstract
Vitamin D, either in its D2 or D3 form, is essential for normal human development during intrauterine life, kidney function and bone health. Vitamin D deficiency has also been linked to cancer development and some autoimmune diseases. Given this huge impact of vitamin D on human health, it is important for daily clinical practice and clinical research to have reliable tools to judge on the vitamin D status. The major circulating form of vitamin D is 25-hydroxyvitamin D (25(OH)D), although it is not the most active metabolite, the concentrations of total 25-hydroxyvitamin D in the serum are currently routinely used in clinical practice to assess vitamin D status. In the circulation, vitamin D - like other steroid hormones - is bound tightly to a special carrier - vitamin D-binding protein (DBP). Smaller amounts are bound to blood proteins - albumin and lipoproteins. Only very tiny amounts of the total vitamin D are free and potentially biologically active. Currently used vitamin D assays do not distinguish between the three forms of vitamin D - DBP-bound vitamin D, albumin-bound vitamin D and free, biologically active vitamin D. Diseases or conditions that affect the synthesis of DBP or albumin thus have a huge impact on the amount of circulating total vitamin D. DBP and albumin are synthesized in the liver, hence all patients with an impairment of liver function have alterations in their total vitamin D blood concentrations, while free vitamin D levels remain mostly constant. Sex steroids, in particular estrogens, stimulate the synthesis of DBP. This explains why total vitamin D concentrations are higher during pregnancy as compared to non-pregnant women, while the concentrations of free vitamin D remain similar in both groups of women. The vitamin D-DBP as well as vitamin D-albumin complexes are filtered through the glomeruli and re-uptaken by megalin in the proximal tubule. Therefore, all acute and chronic kidney diseases that are characterized by a tubular damage, are associated with a loss of vitamin D-DBP complexes in the urine. Finally, the gene encoding DBP protein is highly polymorphic in different human racial groups. In the current review, we will discuss how liver function, estrogens, kidney function and the genetic background might influence total circulating vitamin D levels and will discuss what vitamin D metabolite is more appropriate to measure under these conditions: free vitamin D or total vitamin D.
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Affiliation(s)
- Oleg Tsuprykov
- IFLB, Institute for Laboratory Medicine, Berlin, Berlin, Germany; Institute of Nutritional Sciences, University of Potsdam, Potsdam, Germany
| | - Xin Chen
- Departments of Embryology and Nephrology, The First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Carl-Friedrich Hocher
- Departments of Embryology and Nephrology, The First Affiliated Hospital, Jinan University, Guangzhou, China; First Medical Faculty, Charles University of Prague, Prague, Czech Republic
| | - Roman Skoblo
- IFLB, Institute for Laboratory Medicine, Berlin, Berlin, Germany
| | - Berthold Hocher
- Institute of Nutritional Sciences, University of Potsdam, Potsdam, Germany; Departments of Embryology and Nephrology, The First Affiliated Hospital, Jinan University, Guangzhou, China.
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Blomberg Jensen M, Husted H, Bjerrum PJ, Juul A, Kehlet H. Compromised Activation of Vitamin D After Elective Surgery: A Prospective Pilot Study. JBMR Plus 2018; 2:281-288. [PMID: 30283909 DOI: 10.1002/jbm4.10053] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/20/2018] [Accepted: 04/01/2018] [Indexed: 12/13/2022] Open
Abstract
Surgical stress reduces concentrations of most proteins in serum and necessitates a rapid adjustment of hormones dependent on protein binding. Activation of vitamin D by renal 1α-hydroxylation is dependent on protein binding because 1,25-dihydroxyvitamin D (1,25(OH)2D3) is formed after megalin-mediated reabsorption of 25-hydroxyvitamin D (25OHD) bound to vitamin D binding protein (DBP). Postoperative alterations in serum concentrations of DBP and albumin may therefore impair 1,25(OH)2D3 production. Our objective was to determine sex-specific changes in serum concentrations of vitamin D metabolites and sex steroids 2, 6, 24, and 48 hours and 3 weeks postoperatively. Fourteen women and eleven men aged 45 to 77 years without severe comorbidities undergoing unilateral total knee arthroplasty participated in this prospective study in a tertiary center for arthroplasty (trial ID: NCT02336932). The main outcome measures were total and free serum concentrations of 25OHD, 1,25(OH)2D3, 24,25-dihydroxyvitamin-D, DBP, albumin, sex hormone binding globulin (SHBG), calcium, and parathyroid hormone (PTH). Serum albumin and SHBG decreased postoperatively (Δalbumin48h -18% [-22%; -14%]). Unexpectedly, concentrations of DBP and 25OHD remained unaltered, but 1,25(OH)2D3 declined postoperatively. 1,25(OH)2D3 was 3 weeks after surgery -24% (-40%; -8%) lower than preoperative levels, whereas 24,25-dihydroxyvitamin-D remained unchanged in postmenopausal women. The calculated conversion rate of 25OHD to 1,25(OH)2D3 was strongly associated with serum 25-OHD and PTH preoperatively, whereas serum calcium was most predictive postoperatively. In conclusion, surgery had no effect on serum concentrations of DBP, 25OHD, and PTH, whereas production of 1,25(OH)2D3 was markedly reduced. Further studies are needed to determine duration and putative outcome effects of this postoperative 1,25(OH)2D3 deficit in women, which in part may be due to discordance in CYP27B1 and CYP24A1 activity.
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Affiliation(s)
- Martin Blomberg Jensen
- Division of Bone and Mineral Research HSDM/HMS Harvard University Boston MA USA.,Group of Skeletal, Mineral, and Gonadal Endocrinology University Department of Growth and Reproduction Rigshospitalet Copenhagen Denmark
| | - Henrik Husted
- Department of Orthopedic Surgery Copenhagen University Hospital Hvidovre Denmark.,Section of Surgical Pathophysiology and Lundbeck Foundation Centre for Fast-Track Hip and Knee Arthroplasty Rigshospitalet Copenhagen Denmark
| | | | - Anders Juul
- Group of Skeletal, Mineral, and Gonadal Endocrinology University Department of Growth and Reproduction Rigshospitalet Copenhagen Denmark
| | - Henrik Kehlet
- Section of Surgical Pathophysiology and Lundbeck Foundation Centre for Fast-Track Hip and Knee Arthroplasty Rigshospitalet Copenhagen Denmark
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Bikle DD, Malmstroem S, Schwartz J. Current Controversies: Are Free Vitamin Metabolite Levels a More Accurate Assessment of Vitamin D Status than Total Levels? Endocrinol Metab Clin North Am 2017; 46:901-918. [PMID: 29080642 PMCID: PMC5675107 DOI: 10.1016/j.ecl.2017.07.013] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The free hormone hypothesis postulates that only the nonbound fraction (the free fraction) of hormones that otherwise circulate in blood bound to their carrier proteins is able to enter cells and exert their biologic effects. For the vitamin D metabolites less than 1% (0.4% for 1,25(OH)2D and 0.03% for 25(OH)D) is free, with more than 99% bound to the vitamin D binding protein (DBP) and albumin (approximately 85% and 15%, respectively). Assays to measure the free vitamin D metabolite levels have been developed, and initial studies indicated their value in subjects with altered DBP levels.
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Affiliation(s)
- Daniel D Bikle
- Department of Medicine, University of California San Francisco, San Francisco VA Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
| | - Sofie Malmstroem
- University of California San Francisco, 1700 Owens Street, San Francisco, CA 94158, USA; Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Janice Schwartz
- University of California San Francisco, 1700 Owens Street, San Francisco, CA 94158, USA
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Zand L, Kumar R. The Use of Vitamin D Metabolites and Analogues in the Treatment of Chronic Kidney Disease. Endocrinol Metab Clin North Am 2017; 46:983-1007. [PMID: 29080646 PMCID: PMC5977979 DOI: 10.1016/j.ecl.2017.07.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are associated with abnormalities in bone and mineral metabolism, known as CKD-bone mineral disorder. CKD and ESRD cause skeletal abnormalities characterized by hyperparathyroidism, mixed uremic osteodystrophy, osteomalacia, adynamic bone disease, and frequently enhanced vascular and ectopic calcification. Hyperparathyroidism and mixed uremic osteodystrophy are the most common manifestations due to phosphate retention, reduced concentrations of 1,25-dihydroxyvitamin D, intestinal calcium absorption, and negative calcium balance. Treatment with 1-hydroxylated vitamin D analogues is useful.
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Affiliation(s)
- Ladan Zand
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55901, USA.
| | - Rajiv Kumar
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55901, USA; Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN 55901, USA.
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Berg AH, Bhan I, Powe C, Karumanchi SA, Xu D, Thadhani RI. Acute Homeostatic Changes Following Vitamin D 2 Supplementation. J Endocr Soc 2017; 1:1135-1149. [PMID: 29264568 PMCID: PMC5686571 DOI: 10.1210/js.2017-00244] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/14/2017] [Indexed: 01/08/2023] Open
Abstract
Context: Changes in vitamin D binding protein (DBP) concentrations and catabolism of 25-hydroxyvitamin D to 24,25-dihydroxyvitamin D (24,25D) after vitamin D2 supplementation may alter concentrations and bioavailability of circulating 25-hydroxyvitamin D (25D). Objective: Examine acute changes in vitamin D metabolism and bioavailability after vitamin D2 supplementation. Methods: Study design was secondary analysis of a single-arm interventional study. Thirty consenting volunteers were treated with five 50,000 IU oral doses of ergocalciferol over 2 weeks. Main outcome measures included concentrations of DBP, vitamin D metabolites, and bioavailable 25-hydroxyvitamin D (25D) in pre- and posttreatment serum samples. Results: After supplementation, 25D2 (mean ± standard deviation) increased from 1.4 ± 0.9 ng/mL to 45.3 ± 16.5 ng/mL (P < 0.0001), and 25D3 levels decreased from 26.8 ± 9.9 ng/mL to 19.7 ± 8.2 ng/mL (P < 0.0001). Total 25D (25D2 plus 25D3) increased from 28.2 ± 10.0 ng/mL to 65.0 ± 21.1 ng/mL (152.2% ± 102.5%; P < 0.0001). DBP and total 24,25D concentrations increased 39.1% ± 39.4% (165.6 ± 53.8 µg/mL to 222.0 ± 61.1 µg/mL; P < 0.0001) and 31.3% ± 48.9% (3.9 ± 2.0 ng/mL to 4.7 ± 2.1 ng/mL; P = 0.0147), respectively. In contrast to total 25D, bioavailable 25D increased by 104.4% ± 99.6% (from 5.0 ± 2.0 ng/mL to 8.7 ± 2.7 ng/mL; P < 0.001), and 1,25D increased by 32.3% ± 38.8% (from 45.5 ± 10.7 pg/mL to 58.1 ± 13.0 pg/mL; P = 0.0006). There were no changes in calcium or parathyroid hormone (P > 0.05 for both). Conclusion: Changes after vitamin D2 supplementation involve acute rise in serum DBP and 24,25D, both of which may attenuate the rise in bioavailable 25D and 1,25D.
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Affiliation(s)
- Anders H Berg
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215
| | - Ishir Bhan
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Camille Powe
- Division of Endocrinology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - S Ananth Karumanchi
- Division of Nephrology and Center for Vascular Biology Research, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215
| | - Dihua Xu
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Ravi I Thadhani
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
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Oleröd G, Hultén LM, Hammarsten O, Klingberg E. The variation in free 25-hydroxy vitamin D and vitamin D-binding protein with season and vitamin D status. Endocr Connect 2017; 6:111-120. [PMID: 28179376 PMCID: PMC5428908 DOI: 10.1530/ec-16-0078] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 02/08/2017] [Indexed: 12/20/2022]
Abstract
PURPOSE Serum 25-hydroxy vitamin D [25(OH)D] varies greatly with season at northern latitudes. The purpose of this study was to determine if the seasonal variations in serum total 25(OH)D are followed by a concomitant variation in free 25(OH)D or if the variation is damped by alterations in the binding capacity of DBP. METHODS Serum was collected from 540 healthy blood donors (60% men; mean age 41 ± 13 years) during 12 months and analyzed for total 25(OH)D, directly measured free 25(OH)D, vitamin D-binding protein (DBP) and albumin. Calculated free 25(OH)D was estimated. RESULTS The UV-B radiation during the sampling month was positively correlated with the serum levels of total 25(OH)D (r = 0.355, P < 0.001), directly measured free (r = 0.336, P < 0.001) and calculated free 25(OH)D (r = 0.275, P < 0.001), but not with DBP and albumin. The percentage of free 25(OH)D was higher during the winter months than that during the summer months (0.020 ± 0.005% vs 0.019 ± 0.004%; P = 0.007) and higher in participants with a serum 25(OH)D below 25 nmol/L than that in participants with a serum 25(OH)D above 75 nmol/L (0.031 ± 0.007% vs 0.017 ± 0.003%; P < 0.001). iPTH was correlated with directly measured free 25(OH)D (r = -0.226; P < 0.001), but only weakly with calculated free 25(OH)D (r = -0.095; P = 0.027). CONCLUSIONS Directly measured free serum 25(OH)D was highly correlated with total serum 25(OH)D and followed the same seasonal variation, whereas the serum concentrations of DBP and albumin were stable. The fluctuation in free 25(OH)D was only marginally damped with an increase in the percentage of free 25(OH)D during the winter months and in participants with vitamin D deficiency.
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Affiliation(s)
- Göran Oleröd
- Department of Clinical Chemistry and Transfusion MedicineSahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | | | - Ola Hammarsten
- Department of Clinical Chemistry and Transfusion MedicineSahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Eva Klingberg
- Department of Rheumatology and Inflammation ResearchSahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
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Abstract
Hypercalcemia occurs in up to 4% of the population in association with malignancy, primary hyperparathyroidism, ingestion of excessive calcium and/or vitamin D, ectopic production of 1,25-dihydroxyvitamin D [1,25(OH)2D], and impaired degradation of 1,25(OH)2D. The ingestion of excessive amounts of vitamin D3 (or vitamin D2) results in hypercalcemia and hypercalciuria due to the formation of supraphysiological amounts of 25-hydroxyvitamin D [25(OH)D] that bind to the vitamin D receptor, albeit with lower affinity than the active form of the vitamin, 1,25(OH)2D, and the formation of 5,6-trans 25(OH)D, which binds to the vitamin D receptor more tightly than 25(OH)D. In patients with granulomatous disease such as sarcoidosis or tuberculosis and tumors such as lymphomas, hypercalcemia occurs as a result of the activity of ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages or tumor cells and the formation of excessive amounts of 1,25(OH)2D. Recent work has identified a novel cause of non-PTH-mediated hypercalcemia that occurs when the degradation of 1,25(OH)2D is impaired as a result of mutations of the 1,25(OH)2D-24-hydroxylase cytochrome P450 (CYP24A1). Patients with biallelic and, in some instances, monoallelic mutations of the CYP24A1 gene have elevated serum calcium concentrations associated with elevated serum 1,25(OH)2D, suppressed PTH concentrations, hypercalciuria, nephrocalcinosis, nephrolithiasis, and on occasion, reduced bone density. Of interest, first-time calcium renal stone formers have elevated 1,25(OH)2D and evidence of impaired 24-hydroxylase-mediated 1,25(OH)2D degradation. We will describe the biochemical processes associated with the synthesis and degradation of various vitamin D metabolites, the clinical features of the vitamin D-mediated hypercalcemia, their biochemical diagnosis, and treatment.
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Affiliation(s)
- Peter J Tebben
- Divisions of Endocrinology (P.J.T., R.K.) and Nephrology and Hypertension (R.K.), and Departments of Pediatric and Adolescent Medicine (P.J.T.), Internal Medicine (P.J.T., R.K.), Laboratory Medicine and Pathology (R.J.S.), and Biochemistry in Molecular Biology (R.K.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Ravinder J Singh
- Divisions of Endocrinology (P.J.T., R.K.) and Nephrology and Hypertension (R.K.), and Departments of Pediatric and Adolescent Medicine (P.J.T.), Internal Medicine (P.J.T., R.K.), Laboratory Medicine and Pathology (R.J.S.), and Biochemistry in Molecular Biology (R.K.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Rajiv Kumar
- Divisions of Endocrinology (P.J.T., R.K.) and Nephrology and Hypertension (R.K.), and Departments of Pediatric and Adolescent Medicine (P.J.T.), Internal Medicine (P.J.T., R.K.), Laboratory Medicine and Pathology (R.J.S.), and Biochemistry in Molecular Biology (R.K.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905
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Schwartz JB. Potential Effect of Substituting Estimated Glomerular Filtration Rate for Estimated Creatinine Clearance for Dosing of Direct Oral Anticoagulants. J Am Geriatr Soc 2016; 64:1996-2002. [PMID: 27549687 DOI: 10.1111/jgs.14288] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVES To determine the potential effect of substituting glomerular filtration rate (GFR) estimates for renal clearance estimated using the Cockcroft-Gault method (CrCL-CG) to calculate direct oral anticoagulant (DOAC) dosing. DESIGN Simulation and retrospective data analysis. SETTING Community, academic institution, nursing home. PARTICIPANTS Noninstitutionalized individuals aged 19 to 80 from the National Health and Nutrition Examination Survey (NHANES) (2011/12) (n = 4,687) and medically stable research participants aged 25 to 105 (n = 208). MEASUREMENTS Age, height, weight, sex, race, serum creatinine, CrCL-CG, and GFR (according to the Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration equations). Outcome measures were dosing errors if GFR were to be substituted for CrCL-CG. RESULTS Renal clearance estimates according to all methods were highly correlated (P < .001), although at lower clearances, substitution of GFR estimates for CrCL-CG resulted in failure to recognize needs for dose reductions of rivaroxaban or edoxaban in 28% of NHANES subjects and 47% to 56% of research subjects. At a CrCL-CG of less than 30 mL/min, GFR estimates missed indicated dosage reductions for dabigatran in 18% to 21% of NHANES subjects and 57% to 86% of research subjects. Age and weight contributed to differences between renal clearance estimates (P < .001), but correction of GFR for body surface area (BSA) did not reduce dosing errors. At a CrCL-CG greater than 95 mL/min, edoxaban is not recommended, and GFR esimates misclassified 24% of NHANES and 39% of research subjects. Correction for BSA reduced misclassification to 7% for NHANES and 14% in research subjects. CONCLUSION Substitution of GFR estimates for estimated CrCl can lead to failure to recognize indications for reducing DOAC dose and potentially higher bleeding rates than in randomized trials.
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Affiliation(s)
- Janice B Schwartz
- Jewish Home of San Francisco, San Francisco, California. , .,Departments of Medicine and Bioengineering and Therapeutic Sciences, University of California at San Francisco, San Francisco, California. ,
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Jones KS, Assar S, Prentice A, Schoenmakers I. Vitamin D expenditure is not altered in pregnancy and lactation despite changes in vitamin D metabolite concentrations. Sci Rep 2016; 6:26795. [PMID: 27222109 PMCID: PMC4879580 DOI: 10.1038/srep26795] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 05/10/2016] [Indexed: 11/29/2022] Open
Abstract
Pregnancy and lactation are associated with changes in vitamin D and calcium metabolism but the impact of these changes on vitamin D expenditure is unknown. We measured plasma 25(OH)D3 half-life with a stable-isotope tracer and investigated relationships with vitamin D metabolites in pregnant, lactating and ‘non-pregnant, non-lactating’ (NPNL) women. Vitamin D metabolites, vitamin D binding protein (DBP), PTH and 25(OH)D3 half-life were measured in third-trimester pregnant women (n22) and repeated during lactation 12 weeks post-partum (n14) and twice in NPNL women (n23 and n10, respectively) in rural Gambia where calcium intakes are low with little seasonality in UVB-exposure. 25(OH)D3 half-life was not significantly different between groups (mean(SD): 20.6(6.8), 22.6(7.7), 18.0(4.7) and 17.7(9.5) days in pregnant, lactating and NPNL women, respectively). Plasma 25(OH)D3, 1,25(OH)2D, and DBP were higher in pregnancy, and calculated free-25(OH)D3 and PTH were lower (P < 0.05). In lactation, 25(OH)D3 and 24,25(OH)2D3 were lower compared to pregnant (P < 0.001, P = 0.02) and NPNL women (P = 0.04, P = 0.07). Significant associations were observed between half-life and 25(OH)D3 (+ve) in pregnancy, and in all groups between 25(OH)D3 and free-25(OH)D3 (+ve) and PTH and 25(OH)D3 (−ve) (P < 0.0001). These data suggest that adaptive changes in pregnancy and lactation occur that prevent pronounced changes in vitamin D expenditure.
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Affiliation(s)
- Kerry S Jones
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, CB1 9NL, UK.,MRC Keneba, MRC Unit, Banjul, The Gambia
| | - Shima Assar
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, CB1 9NL, UK
| | - Ann Prentice
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, CB1 9NL, UK.,MRC Keneba, MRC Unit, Banjul, The Gambia
| | - Inez Schoenmakers
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, CB1 9NL, UK
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Schwartz JB, Kane L, Bikle D. Response of Vitamin D Concentration to Vitamin D3 Administration in Older Adults without Sun Exposure: A Randomized Double-Blind Trial. J Am Geriatr Soc 2016; 64:65-72. [PMID: 26782853 DOI: 10.1111/jgs.13774] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To determine the dose-response relationship between 25-hydroxyvitamin D (25(OH)D) and supplemental vitamin D3 in elderly nursing home residents. DESIGN Randomized double-blind investigation. SETTING Nursing home. PARTICIPANTS Of 81 women (n=51) and men (n=30) (mean age 87.4±8) enrolled, 72 completed the study. INTERVENTION Sixteen weeks of oral vitamin D3 at 800, 2,000, or 4,000 IU/d or 50,000 IU/wk. MEASUREMENTS The main outcome was 25(OH)D concentrations (tandem mass spectrometry) after 16 weeks. Free 25(OH)D and intact parathyroid hormone (iPTH) were also analyzed. Safety monitoring of calcium and estimated glomerular filtration rate was performed, and adherence and clinical status were measured. RESULTS 25(OH)D concentrations increased with dose (P<.001) and were higher with 50,000 IU/wk (P<.001) than other doses and with 4,000 IU/d than 800 or 2,000 IU/d, but 800 IU and 2,000 IU/d did not differ. One subject receiving 800 IU/d had concentrations less than 20 ng/mL. All subjects receiving more than 2000 IU/d had concentrations of 20 ng/mL and greater. Free 25(OH)D concentrations rose with total 25(OH) vitamin D. Total and free 25(OH)D were related to calcium concentrations; only free 25(OH)D was related to iPTH. CONCLUSION 25(OH)D increased linearly with 800 to 4,000 IU/d and 50,000 IU/wk of vitamin D3, without a ceiling effect. Data suggest that some elderly adults will require more than 800 IU/d of vitamin D3 to ensure adequate vitamin D levels. Changes in 25(OH)D with vitamin D3 were related to starting concentrations (greatest with the lowest concentrations and unchanged with 800 and 2,000 IU/d if 20-40 ng/mL). Relationships between serum calcium and iPTH and free 25(OH)D suggest the potential for free 25(OH)D in defining optimal 25(OH)D concentrations.
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Affiliation(s)
- Janice B Schwartz
- Jewish Home of San Francisco, San Francisco, California.,Department of Medicine, University of California at San Francisco, San Francisco, California.,Department of Bioengineering and Therapeutic Sciences, University of California at San Francisco, San Francisco, California
| | - Lynn Kane
- Jewish Home of San Francisco, San Francisco, California
| | - Daniel Bikle
- Department of Medicine, University of California at San Francisco, San Francisco, California.,Department of Dermatology, University of California at San Francisco, San Francisco, California
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Effects of Vitamin D Supplementation on Serum 25-Hydroxyvitamin D Concentrations in Cirrhotic Patients: A Randomized Controlled Trial. Nutrients 2016; 8:nu8050278. [PMID: 27171112 PMCID: PMC4882691 DOI: 10.3390/nu8050278] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/26/2016] [Accepted: 05/04/2016] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The liver is crucial for 25-hydroxyvitamin D (25(OH)D) metabolism, and vitamin D deficiency is highly prevalent in patients with cirrhosis and predicts adverse outcomes. We aimed to evaluate whether vitamin D supplementation in patients with cirrhosis is effective in increasing 25(OH)D serum concentrations. Secondary outcome measures included liver function tests (aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyltransferase (GGT), and alkaline phosphatase (AP)), albumin, International Normalized Ratio (INR), bilirubin, the liver fibrosis marker hyaluronic acid, and parameters of mineral metabolism including parathyroid hormone (PTH). METHODS This is a double-center, double-blind, placebo-controlled study conducted from December 2013 to May 2014 at the Medical University of Graz, and the hospital Hoergas-Enzenbach, Austria. We enrolled 36 consecutive patients with cirrhosis and 25(OH)D concentrations below 30 ng/mL. Study participants were randomly allocated to receive either 2800 International Units of vitamin D3 per day as oily drops (n = 18) or placebo (n = 18) for 8 weeks. RESULTS Thirty-three study participants (mean (SD) age: 60 (9) years; 21% females; 25(OH)D: 15.6 (7.4) ng/mL) completed the trial. The mean treatment effect (95% CI) for 25(OH)D was 15.2 (8.0 to 22.4) ng/mL (p < 0.001). There was no significant effect on any secondary outcome. CONCLUSIONS In this randomized controlled trial, vitamin D supplementation increases 25(OH)D serum concentrations, even in cirrhotic patients.
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Nielson CM, Jones KS, Chun RF, Jacobs JM, Wang Y, Hewison M, Adams JS, Swanson CM, Lee CG, Vanderschueren D, Pauwels S, Prentice A, Smith RD, Shi T, Gao Y, Schepmoes AA, Zmuda JM, Lapidus J, Cauley JA, Bouillon R, Schoenmakers I, Orwoll ES. Free 25-Hydroxyvitamin D: Impact of Vitamin D Binding Protein Assays on Racial-Genotypic Associations. J Clin Endocrinol Metab 2016; 101:2226-34. [PMID: 27007693 PMCID: PMC4870848 DOI: 10.1210/jc.2016-1104] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/11/2016] [Indexed: 01/19/2023]
Abstract
CONTEXT Total 25-hydroxyvitamin D (25OHD) is a marker of vitamin D status and is lower in African Americans than in whites. Whether this difference holds for free 25OHOD (f25OHD) is unclear, considering reported genetic-racial differences in vitamin D binding protein (DBP) used to calculate f25OHD. OBJECTIVES Our objective was to assess racial-geographic differences in f25OHD and to understand inconsistencies in racial associations with DBP and calculated f25OHD. DESIGN This study used a cross-sectional design. SETTING The general community in the United States, United Kingdom, and The Gambia were included in this study. PARTICIPANTS Men in Osteoporotic Fractures in Men and Medical Research Council studies (N = 1057) were included. EXPOSURES Total 25OHD concentration, race, and DBP (GC) genotype exposures were included. OUTCOME MEASURES Directly measured f25OHD, DBP assessed by proteomics, monoclonal and polyclonal immunoassays, and calculated f25OHD were the outcome measures. RESULTS Total 25OHD correlated strongly with directly measured f25OHD (Spearman r = 0.84). Measured by monoclonal assay, mean DBP in African-ancestry subjects was approximately 50% lower than in whites, whereas DBP measured by polyclonal DBP antibodies or proteomic methods was not lower in African-ancestry. Calculated f25OHD (using polyclonal DBP assays) correlated strongly with directly measured f25OHD (r = 0.80-0.83). Free 25OHD, measured or calculated from polyclonal DBP assays, reflected total 25OHD concentration irrespective of race and was lower in African Americans than in US whites. CONCLUSIONS Previously reported racial differences in DBP concentration are likely from monoclonal assay bias, as there was no racial difference in DBP concentration by other methods. This confirms the poor vitamin D status of many African-Americans and the utility of total 25OHD in assessing vitamin D in the general population.
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Affiliation(s)
| | | | - Rene F. Chun
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Jon M. Jacobs
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Ying Wang
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Martin Hewison
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - John S. Adams
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Christine M. Swanson
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Christine G. Lee
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Dirk Vanderschueren
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Steven Pauwels
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Ann Prentice
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Richard D. Smith
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Tujin Shi
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Yuqian Gao
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Athena A. Schepmoes
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Joseph M. Zmuda
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Jodi Lapidus
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | - Jane A. Cauley
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
| | | | | | | | - for the Osteoporotic Fractures in Men (MrOS) Research Group
- Bone & Mineral Unit (C.M.N., Y.W., C.M.S., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; School of Public Health (C.M.N., J.L.), Oregon Health & Science University, Portland, Oregon 97239; Medical Research Council Human Nutrition Research (K.S.J., A.P., I.S.), Cambridge, UK CB1 9NL; Department of Orthopedics (R.F.C.), University of California, Los Angeles, California 90095; Pacific Northwest National Laboratory (J.M.J., R.D.S., T.S., Y.G., A.A.S.), Richland, Washington 99354; Institute of Metabolism and Systems Research (M.H.), University of Birmingham, Birmingham, UK B15 2TT; University of California (J.S.A.), Los Angeles, California 90095; School of Medicine (C.M.S., C.G.L., E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Portland Veterans Affairs Medical Center (C.G.L.), Oregon 97239; Laboratory of Diagnostic Medicine (D.V.), KU Leuven, 3000 Belgium; Laboratory of Clinical and Experimental Endocrinology (D.V., R.B.), KU Leuven, 3000 Belgium; Department of Cardiovascular Sciences (S.P.), KU Leuven, Belgium 3000; Department of Laboratory Medicine (S.P.), University Hospitals Leuven, 3000 Belgium; MRC Keneba (A.P.), Keneba, The Gambia; and Department of Epidemiology (J.M.Z., J.A.C.), University of Pittsburgh, Pennsylvania 15261
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Aloia J, Dhaliwal R, Mikhail M, Shieh A, Stolberg A, Ragolia L, Fazzari M, Abrams SA. Free 25(OH)D and Calcium Absorption, PTH, and Markers of Bone Turnover. J Clin Endocrinol Metab 2015; 100:4140-5. [PMID: 26312580 PMCID: PMC4702446 DOI: 10.1210/jc.2015-2548] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
CONTEXT It has been proposed that serum free 25-hydroxyvitamin D [25(OH)D] may better reflect vitamin D action than total 25(OH)D. An ELISA for serum free 25(OH)D has recently become available, permitting direct assay. OBJECTIVE To determine whether serum free 25(OH)D provides additional information in relation to calcium absorption and other biomarkers of vitamin D action compared to total serum 25(OH)D. SETTING Ambulatory research setting in a teaching hospital. OUTCOME Serum free 25(OH)D measured in a previously performed study of varied doses of vitamin D3 (placebo and 800, 2000, and 4000 IU) on calcium absorption, PTH, procollagen type 1 N-terminal propeptide, and C-terminal telopeptides of type I collagen. Free 25(OH)D was measured by ELISA. Calcium absorption was measured at baseline and at 10 weeks using stable dual calcium isotopes. RESULTS Seventy-one subjects completed this randomized, placebo-controlled trial. Baseline group mean free and total 25(OH)D varied from 4.7 ± 1.8 to 5.4 ± 1.5 pg/mL, and from 23.7 ± 5.9 to 25.9 ± 6.1 ng/mL, respectively. Participants assigned to the 4000-IU dose arm achieved free 25(OH)D levels of 10.4 pg/mL and total 25(OH)D levels of 40.4 ng/mL. Total and free 25(OH)D were highly correlated at baseline and after increasing vitamin D dosing (r = 0.80 and 0.85, respectively). Free 25(OH)D closely reflected changes in total 25(OH)D. PTH was similarly correlated at baseline and follow-up with total and free 25(OH)D. Serum C-terminal telopeptides of type I collagen had a moderate positive correlation with total and free 25(OH)D at follow-up. The serum 1,25-dihydroxyvitamin D change increased significantly with the change in 25(OH)D but not with the change in free 25(OH)D. CONCLUSION There was no advantage from measuring free over total 25(OH)D in assessing the response of calcium absorption, PTH, and markers of bone turnover to vitamin D. Free 25(OH)D responded to increasing doses of vitamin D in a similar fashion to total 25(OH)D.
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Affiliation(s)
- John Aloia
- Winthrop University Hospital, Mineola, New York 11501
| | | | | | - Albert Shieh
- Winthrop University Hospital, Mineola, New York 11501
| | | | - Louis Ragolia
- Winthrop University Hospital, Mineola, New York 11501
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Aloia J, Mikhail M, Dhaliwal R, Shieh A, Usera G, Stolberg A, Ragolia L, Islam S. Free 25(OH)D and the Vitamin D Paradox in African Americans. J Clin Endocrinol Metab 2015; 100:3356-63. [PMID: 26161453 PMCID: PMC4570168 DOI: 10.1210/jc.2015-2066] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT African Americans have a lower total serum 25-hydroxyvitamin D [25(OH)D] but superior bone health. This has been referred to as a paradox. A recent publication found that free serum 25(OH)D is the same in black and white individuals. However, the study was criticized because an indirect method was used to measure free 25(OH)D. A direct method has recently been developed. OBJECTIVE We hypothesized that although total serum 25(OH)D is lower in African Americans, free serum 25(OH)D measured directly would not differ between races. DESIGN White and black healthy postmenopausal women were matched for age and body mass index. Serum total 25(OH)D, PTH, 1,25-dihydroxyvitamin D, vitamin D binding protein (VDBP), and bone density were measured. Measurement of free 25(OH)D was carried out using an ELISA. SETTING The study was conducted at an ambulatory research unit in a teaching hospital. OUTCOME A cross-racial comparison of serum free 25(OH)D was performed. RESULTS A propensity match resulted in the selection of a total of 164 women. Total 25(OH)D was lower in black women (19.5 ± 4.7 vs 26.9 ± 6.4 ng/mL), but a direct measurement of free 25(OH)D revealed almost identical values (5.25 ± 1.2 vs 5.25 ± 1.3 ng/mL) between races. VDBP was significantly lower in blacks when using a monoclonal-based ELISA but higher with a polyclonal-based ELISA. Serum PTH, 1,25-dihydroxyvitamin D, and bone density were higher in African Americans. CONCLUSIONS Free serum 25(OH)D is the same across races despite the lower total serum 25(OH)D in black women. Results comparing VDBP between races using a monoclonal vs a polyclonal assay were discordant.
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Affiliation(s)
- John Aloia
- Winthrop University Hospital, Mineola, New York 11501
| | | | | | - Albert Shieh
- Winthrop University Hospital, Mineola, New York 11501
| | - Gianina Usera
- Winthrop University Hospital, Mineola, New York 11501
| | | | - Louis Ragolia
- Winthrop University Hospital, Mineola, New York 11501
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Tanner SB, Harwell SA. More than healthy bones: a review of vitamin D in muscle health. Ther Adv Musculoskelet Dis 2015; 7:152-9. [PMID: 26288665 DOI: 10.1177/1759720x15588521] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Vitamin D has known importance to bone health including calcium and phosphate homeostasis and appears to have a role in skeletal muscle health as well. Cases of vitamin D deficiency and insufficiency have been associated with poor muscle health. While the exact effects and mechanism of action remains controversial, current data lean towards insufficient vitamin D playing a role in musculoskeletal pain, sarcopenia, myopathy, falls and indirectly via cerebellar and cognitive dysfunction. Sophisticated experimental techniques have allowed detection of the vitamin D receptor (VDR) on skeletal muscle and cerebellar tissue, which if validated in further large studies, could confirm the mechanism of vitamin D in these associations. While further study is required, vitamin D repletion can have a substantial impact on muscle as well as bone health.
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Affiliation(s)
- S Bobo Tanner
- Vanderbilt University Medical Center - Rheumatology and Allergy, 2611 West End Ave, Suite 210, Nashville, Tennessee 37203, USA
| | - Susan A Harwell
- Vanderbilt University Medical Center - Rheumatology, 1161 21st Avenue So., T-3113 MCN, Nashville, Tennessee 37232, USA
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Le Goff C, Cavalier E, Souberbielle JC, González-Antuña A, Delvin E. Measurement of circulating 25-hydroxyvitamin D: A historical review. Pract Lab Med 2015; 2:1-14. [PMID: 28932799 PMCID: PMC5597717 DOI: 10.1016/j.plabm.2015.04.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/24/2015] [Accepted: 04/16/2015] [Indexed: 11/26/2022] Open
Abstract
The constantly increasing requests for the measurement of serum 25-hydroxyvitamin D over the last years has led reagent manufacturers to market different automated and semi-automated methods, that being unfortunately not fully harmonized, yield different results. Liquid chromatography coupled to tandem mass spectrometry (LC/MS2) has more recently been introduced. This approach allows the distinction between the two forms of 25-hydroxyvitamin D and to measure other metabolites. This approach also requires harmonization to curtail the differences between the different analytical methods. To meet this requirement, the American National Institutes of Health (NIH), the Centre for Disease Control and Prevention (CDC) in Atlanta, the National Institute of Standards and Technology (NIST) and the vitamin D Reference laboratory of Ghent University have pooled their expertise to develop a standardization program. This article reviews the main elements and the difficulties of the automated and semi-automated methods for 25-hydroxyvitamin D, from sample preparation to the analytical phase, as well as those related to mass spectrometry. It also emphasizes the need for standardization to better define the clinical decision thresholds of vitamin D nutritional status.
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Affiliation(s)
- C. Le Goff
- Service de Chimie Clinique, CHU de Liège, Belgium
| | - E. Cavalier
- Service de Chimie Clinique, CHU de Liège, Belgium
| | - J.-C. Souberbielle
- Service des Explorations Fonctionnelles Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | | | - E. Delvin
- Centre de Recherche, CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montréal, Québec, Canada H3T 1C5
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43
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Refaat B, El-Shemi AG, Ashshi A, Azhar E. Vitamin D and chronic hepatitis C: effects on success rate and prevention of side effects associated with pegylated interferon-α and ribavirin. Int J Clin Exp Med 2015; 8:10284-10303. [PMID: 26379820 PMCID: PMC4565203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 07/01/2015] [Indexed: 06/05/2023]
Abstract
Chronic hepatitis C (CHC) is one of the most common causes of liver diseases worldwide, affecting 3% of the world population and 3 to 4 million people acquire new infection annually. Despite the recent introduction of novel antiviral drugs for the treatment of CHC, these drugs are expensive and the access to them is not an option for many patients. Hence, the traditional therapy by pegylated interferon-α (Peg-IFN-α) and ribavirin may still have a role in the clinical management of CHC especially in developing countries. However, this standard therapy is associated with several severe extra-hepatic side effects and the most common adverse events are hematological abnormalities and thyroid disorders and they could result in dose reduction and/or termination of therapy. Vitamin D has been shown to be a key regulatory element of the immune system, and its serum concentrations correlate with the severity of liver damage and the development of liver fibrosis/cirrhosis. Furthermore, supplementation with vitamin D with Peg-IFN-α based therapy for the treatment of CHC could be beneficial in increase the response rate to Peg-INF-α based therapy. Vitamin D has also been shown to regulate the thyroid functions and the process of erythropoiesis. This review appraises the data to date researching the role of vitamin D during the treatment of CHC and the potential role of vitamin D in preventing/treating Peg-IFN-α induced thyroiditis and anemia during the course of treatment.
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Affiliation(s)
- Bassem Refaat
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Umm Al-Qura UniversityAl Abdeyah, Makkah, PO Box 7607, KSA
| | - Adel Galal El-Shemi
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Umm Al-Qura UniversityAl Abdeyah, Makkah, PO Box 7607, KSA
- Department of Pharmacology, Faculty of Medicine, Assiut UniversityEgypt
| | - Ahmed Ashshi
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Umm Al-Qura UniversityAl Abdeyah, Makkah, PO Box 7607, KSA
| | - Esam Azhar
- Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz UniversityJeddah, KSA
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz UniversityJeddah, Saudi Arabia
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Bhan I, Dobens D, Tamez H, Deferio JJ, Li YC, Warren HS, Ankers E, Wenger J, Tucker JK, Trottier C, Pathan F, Kalim S, Nigwekar SU, Thadhani R. Nutritional vitamin D supplementation in dialysis: a randomized trial. Clin J Am Soc Nephrol 2015; 10:611-9. [PMID: 25770176 DOI: 10.2215/cjn.06910714] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 12/22/2014] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND OBJECTIVES Vitamin D (25-hydroxyvitamin D; 25[OH]D) deficiency is common in patients initiating long-term hemodialysis, but the safety and efficacy of nutritional vitamin D supplementation in this population remain uncertain. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This randomized, placebo-controlled, parallel-group multicenter trial compared two doses of ergocalciferol with placebo between October 2009 and March 2013. Hemodialysis patients (n=105) with 25(OH)D levels ≤32 ng/ml from 32 centers in the Northeast United States were randomly assigned to oral ergocalciferol, 50,000 IU weekly (n=36) or monthly (n=33), or placebo (n=36) for a 12-week treatment period. The primary endpoint was the achievement of vitamin D sufficiency (25[OH]D >32 ng/ml) at the end of the 12-week treatment period. Survival was assessed through 1 year. RESULTS Baseline characteristics were similar across all arms, with overall mean±SD 25(OH)D levels of 21.9±6.9 ng/ml. At 12 weeks, vitamin D sufficiency (25[OH]D >32 ng/ml) was achieved in 91% (weekly), 66% (monthly), and 35% (placebo) (P<0.001). Mean 25(OH)D was significantly higher in both the weekly (49.8±2.3 ng/ml; P<0.001) and monthly (38.3±2.4 ng/ml; P=0.001) arms compared with placebo (27.4±2.3 ng/ml). Calcium, phosphate, parathyroid hormone levels, and active vitamin D treatment did not differ between groups. All-cause and cause-specific hospitalizations and adverse events were similar between groups during the intervention period. Lower all-cause mortality among ergocalciferol-treated participants was not statistically significant (hazard ratio, 0.28; 95% confidence interval, 0.07 to 1.19). CONCLUSIONS Oral ergocalciferol can increase 25(OH)D levels in incident hemodialysis patients without significant alterations in blood calcium, phosphate, or parathyroid hormone during a 12-week period.
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Affiliation(s)
- Ishir Bhan
- Division of Nephrology, Department of Medicine,
| | | | | | | | - Yan Chun Li
- Department of Medicine, Division of Biological Sciences, The University of Chicago, Chicago, Illinois
| | - H Shaw Warren
- Infectious Disease Unit, Departments of Pediatrics and Medicine, and
| | | | | | | | | | - Fridosh Pathan
- Pharmacy Department, Massachusetts General Hospital, Boston, Massachusetts; and
| | - Sahir Kalim
- Division of Nephrology, Department of Medicine
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Rousseau AF, Damas P, Janssens M, Kalin S, Ledoux D, Le Goff C, Gadisseur R, Delanaye P, Cavalier E. Critical care and vitamin D status assessment: what about immunoassays and calculated free 25OH-D? Clin Chim Acta 2014; 437:43-7. [PMID: 25020235 DOI: 10.1016/j.cca.2014.07.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 07/03/2014] [Accepted: 07/04/2014] [Indexed: 01/29/2023]
Abstract
BACKGROUND Interpretation of 25OH-D measurement during critical care (CC) may be problematic due to variations of binding protein concentrations (albumin, ALB, and vitamin D binding protein, VDBP). Determination of free 25OH-D concentration may thus be relevant in CC patients. The aim of this observational study was to evaluate effects of an acute hemodilution on vitamin D (VD) status. METHODS Blood samples were obtained before (T1) and after a crystalloid load (T2) administered at anesthesia induction for minor surgery. 25OH-D was measured with LC-MS/MS and with 3 immunoassays (IA): DiaSorin Liaison, IDS iSYS and bioMérieux Vidas. VDBP was measured with the R&D Elisa and ALB on Cobas. Free 25OH-D was calculated using published formula. Accuracy of each 25OH-D IA was calculated as the percentage of IA values within 20% of their respective LC-MS/MS values. Performances of the three AI were compared with LC-MC/MS using Bland-Altman analysis. RESULTS Twenty adults were included. Compared to T1 values, VDBP, ALB and LC-MS/MS values decreased in parallel by a mean of 23% at T2. IA values decreased less significantly (12, 14 and 15% for Liaison, iSYS and Vidas, respectively). IA-based calculated free 25OH-D significantly increased after dilution, while LC-MS/MS-based free values remained stable. At T1 and T2, bias were demonstrable for all IA. After hemodilution, bias would lead to overestimation for the three IA. Accuracy of IA decreased after dilution. CONCLUSIONS Due to matrix effects, compared to LC-MS/MS, IA results were impacted by hemodilution. In CC patients, LC-MS/MS seems to be the best option to measure 25OH-D. Specific LC-MS/MS method should be developed to measure free 25OH-D.
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Affiliation(s)
- Anne-Françoise Rousseau
- Burn Centre and General Intensive Care Department, University of Liège, University Hospital, Sart-Tilman, Liège, Belgium.
| | - Pierre Damas
- Burn Centre and General Intensive Care Department, University of Liège, University Hospital, Sart-Tilman, Liège, Belgium
| | - Marc Janssens
- Anesthesiology Department, University of Liège, University Hospital, Sart-Tilman, Liège, Belgium
| | - Saban Kalin
- Anesthesiology Department, University of Liège, University Hospital, Sart-Tilman, Liège, Belgium
| | - Didier Ledoux
- Burn Centre and General Intensive Care Department, University of Liège, University Hospital, Sart-Tilman, Liège, Belgium
| | - Caroline Le Goff
- Clinical Chemistry Department, University of Liège, University Hospital, Sart-Tilman, Liège, Belgium
| | - Romy Gadisseur
- Clinical Chemistry Department, University of Liège, University Hospital, Sart-Tilman, Liège, Belgium
| | - Pierre Delanaye
- Nephrology Department, University of Liège, University Hospital, Sart-Tilman, Liège, Belgium
| | - Etienne Cavalier
- Clinical Chemistry Department, University of Liège, University Hospital, Sart-Tilman, Liège, Belgium
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46
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Yousefzadeh P, Shapses SA, Wang X. Vitamin D Binding Protein Impact on 25-Hydroxyvitamin D Levels under Different Physiologic and Pathologic Conditions. Int J Endocrinol 2014; 2014:981581. [PMID: 24868205 PMCID: PMC4020458 DOI: 10.1155/2014/981581] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Revised: 04/03/2014] [Accepted: 04/10/2014] [Indexed: 12/15/2022] Open
Abstract
There is a high prevalence of vitamin D deficiency worldwide, but how to define vitamin D deficiency is controversial. Currently, the plasma concentration of total 25-hydroxyvitamin D [25(OH)D] is considered an indicator of vitamin D status. The free hormone hypothesis states that protein-bound hormones are inactive while unbound hormones are free to exert biological activity. The majority of circulating 25(OH)D and 1,25(OH)2D is tightly bound to vitamin D binding protein (DBP), 10-15% is bound to albumin, and less than 1% of circulating vitamin D exists in an unbound form. While DBP is relatively stable in most healthy populations, a recent study showed that there are gene polymorphisms associated with race and ethnicity that could alter DBP levels and binding affinity. Furthermore, in some clinical situations, total vitamin D levels are altered and knowing whether DBP is also altered may have treatment implications. The aim of this review is to assess DBP concentration in different physiological and pathophysiological conditions. We suggest that DBP should be considered in the interpretation of 25(OH)D levels.
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Affiliation(s)
- Pegah Yousefzadeh
- Division of Endocrinology, Metabolism & Nutrition, Department of Medicine, Rutgers University-Robert Wood Johnson Medical School, New Brunswick, NJ 08903, USA
| | - Sue A. Shapses
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ 08901, USA
| | - Xiangbing Wang
- Division of Endocrinology, Metabolism & Nutrition, Department of Medicine, Rutgers University-Robert Wood Johnson Medical School, New Brunswick, NJ 08903, USA
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