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Gottlieb C, Henrich M, Liu PT, Yacoubian V, Wang J, Chun R, Adams JS. High- Throughput CAMP Assay (HiTCA): A Novel Tool for Evaluating the Vitamin D-Dependent Antimicrobial Response. Nutrients 2023; 15:1380. [PMID: 36986109 PMCID: PMC10051182 DOI: 10.3390/nu15061380] [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: 02/14/2023] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 03/14/2023] Open
Abstract
Vitamin D is known to modulate human immune responses, and vitamin D deficiency is associated with increased susceptibility to infection. However, what constitutes sufficient levels or whether vitamin D is useful as an adjuvant therapeutic is debated, much in part because of inadequate elucidation of mechanisms underlying vitamin D's immune modulatory function. Cathelicidin antimicrobial peptide (CAMP) has potent broad-spectrum activity, and the CAMP gene is regulated in human innate immune cells by active 1,25(OH)2D3, a product of hydroxylation of inactive 25(OH)D3 by CYP27B1-hydroxylase. We developed a CRISPR/Cas9-edited human monocyte-macrophage cell line containing the mCherry fluorescent reporter gene at the 3' end of the endogenous CAMP gene. The High Throughput CAMP Assay (HiTCA) developed here is a novel tool for evaluating CAMP expression in a stable cell line that is scalable for a high-throughput workflow. Application of HiTCA to serum samples from a small number of human donors (n = 10) showed individual differences in CAMP induction that were not fully accounted for by the serum vitamin D metabolite status of the host. As such, HiTCA may be a useful tool that can advance our understanding of the human vitamin D-dependent antimicrobial response, which is being increasingly appreciated for its complexity.
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Affiliation(s)
- Carter Gottlieb
- Department of Orthopaedic Surgery, University of California, Los Angeles, CA 90095, USA
| | - Mason Henrich
- Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Philip T. Liu
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Vahe Yacoubian
- Department of Orthopaedic Surgery, University of California, Los Angeles, CA 90095, USA
| | - Jeffery Wang
- Department of Orthopaedic Surgery, University of California, Los Angeles, CA 90095, USA
| | - Rene Chun
- Department of Orthopaedic Surgery, University of California, Los Angeles, CA 90095, USA
| | - John S. Adams
- Department of Orthopaedic Surgery, University of California, Los Angeles, CA 90095, USA
- Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA 90095, USA
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2
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Duchow EG, Sibilska-Kaminski IK, Plum LA, DeLuca HF. Vitamin D esters are the major form of vitamin D produced by UV irradiation in mice. Photochem Photobiol Sci 2022; 21:1399-1404. [PMID: 35488978 DOI: 10.1007/s43630-022-00230-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 04/07/2022] [Indexed: 11/25/2022]
Abstract
The primary source of vitamin D3 for humans is that produced in skin by ultraviolet irradiation. Ultraviolet (UV) B (UVB, 280-310 nm) light causes the isomerization of 7-dehydrocholesterol (7-DHC) to pre-vitamin D3 that is thermally isomerized to vitamin D3. In addition to free vitamin D3, it has been previously reported that esterified vitamin D3 is also found in the skin of rats irradiated with UVB. We found that a large fraction of the vitamin D3 precursor, 7-dehydrocholesterol is in the esterified form. Following UVB irradiation, vitamin D3 esters represent the majority of tissue vitamin D3, comprising approximately 80% in mice. Examination of vitamin D3 ester transport from skin in DBP-/- mice demonstrated that skin vitamin D3 ester content decreased only in the presence of DBP. No significant binding of vitamin D3 esters by serum was observed and no vitamin D3 esters were detectable in mouse serum after UVB treatment, indicating that the esters are hydrolyzed prior to transport into the circulation. The significance of vitamin D3 esters and their hydrolysis is the subject of current investigation.
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Affiliation(s)
- Elizabeth G Duchow
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, 271a Biochemistry, Madison, WI, 53706, USA
| | - Izabela K Sibilska-Kaminski
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, 271a Biochemistry, Madison, WI, 53706, USA
| | - Lori A Plum
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, 271a Biochemistry, Madison, WI, 53706, USA
| | - Hector F DeLuca
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, 271a Biochemistry, Madison, WI, 53706, USA.
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3
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Heo YJ, Lee YJ, Lee K, Kim JH, Shin CH, Lee YA, Song J. Total, bioavailable and free 25-hydroxyvitamin D levels as functional indicators for bone parameters in healthy children. PLoS One 2021; 16:e0258585. [PMID: 34648586 PMCID: PMC8516284 DOI: 10.1371/journal.pone.0258585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 09/30/2021] [Indexed: 11/21/2022] Open
Abstract
Objectives Vitamin D is essential for bone health. Not only total but also free 25-hydroxyvitamin D (25OHD) may contribute to bone mass. We sought to determine which vitamin D measure best reflected clinical and bone parameters in healthy children. Methods A cross-sectional study including 146 healthy children (71 boys, 9.5 ± 1.9 years) conducted at a tertiary medical center. We used a multiplex liquid chromatography-tandem mass spectrometry-based assay to simultaneously measure vitamin D metabolites. The bioavailable and free 25OHD (25OHDBioA and 25OHDFree) levels were calculated using the genotype-specific or genotype-constant affinity coefficients of vitamin D-binding proteins (yielding spe-25OHDBioA, spe-25OHDFree and con-25OHDBioA, con-25OHDFree respectively). The 25OHDFree level was directly measured (m-25OHDFree). Bone mineral content (BMC) and bone mineral density (BMD) were assessed via dual-energy X-ray absorptiometry. Results The total 25OHD (25OHDTotal), the two forms of 25OHDBioA, the three forms of 25OHDFree, and 24,25-dihydroxyvitamin D3 levels correlated with parathyroid hormone level (all p < 0.01). Serum 25OHDTotal and m-25OHDFree levels were influenced by age, pubertal status, season, body mass index (BMI), daylight hours, and vitamin D intake (all p < 0.05). The con-25OHDBioA and con-25OHDFree levels better reflected pubertal status and daylight hours than did the spe-25OHDBioA and spe-25OHDFree levels (both p < 0.01). The association between the 25OHDTotal level and bone parameters varied according to the BMI (interaction p < 0.05). In 109 normal-weight children, the con-25OHDBioA and con-25OHDFree levels correlated with total body BMC and BMD (both p < 0.05), whereas the 25OHDTotal and 24,25-dihydroxyvitamin D3 levels were associated with total body BMC (both p < 0.05). No such association was found in overweight or obese children. Conclusions In healthy children, total, bioavailable, and free 25OHD levels comparably reflected lifestyle factors. In normal-weight children, the con-25OHDBioA and con-25OHDFree, but not m-25OHDFree levels, reflected bone mass, as did the 25OHDTotal level.
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Affiliation(s)
- You Joung Heo
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Yun Jeong Lee
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Kyunghoon Lee
- Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Jae Hyun Kim
- Department of Pediatrics, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Choong Ho Shin
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Young Ah Lee
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul National University College of Medicine, Seoul, Korea
- * E-mail: (YAL); (JS)
| | - Junghan Song
- Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
- * E-mail: (YAL); (JS)
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4
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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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5
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Rhodes JM, Subramanian S, Laird E, Griffin G, Kenny RA. Perspective: Vitamin D deficiency and COVID-19 severity - plausibly linked by latitude, ethnicity, impacts on cytokines, ACE2 and thrombosis. J Intern Med 2021; 289:97-115. [PMID: 32613681 PMCID: PMC7361294 DOI: 10.1111/joim.13149] [Citation(s) in RCA: 147] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 06/16/2020] [Accepted: 06/23/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND SARS-CoV-2 coronavirus infection ranges from asymptomatic through to fatal COVID-19 characterized by a 'cytokine storm' and lung failure. Vitamin D deficiency has been postulated as a determinant of severity. OBJECTIVES To review the evidence relevant to vitamin D and COVID-19. METHODS Narrative review. RESULTS Regression modelling shows that more northerly countries in the Northern Hemisphere are currently (May 2020) showing relatively high COVID-19 mortality, with an estimated 4.4% increase in mortality for each 1 degree latitude north of 28 degrees North (P = 0.031) after adjustment for age of population. This supports a role for ultraviolet B acting via vitamin D synthesis. Factors associated with worse COVID-19 prognosis include old age, ethnicity, male sex, obesity, diabetes and hypertension and these also associate with deficiency of vitamin D or its response. Vitamin D deficiency is also linked to severity of childhood respiratory illness. Experimentally, vitamin D increases the ratio of angiotensin-converting enzyme 2 (ACE2) to ACE, thus increasing angiotensin II hydrolysis and reducing subsequent inflammatory cytokine response to pathogens and lung injury. CONCLUSIONS Substantial evidence supports a link between vitamin D deficiency and COVID-19 severity but it is all indirect. Community-based placebo-controlled trials of vitamin D supplementation may be difficult. Further evidence could come from study of COVID-19 outcomes in large cohorts with information on prescribing data for vitamin D supplementation or assay of serum unbound 25(OH) vitamin D levels. Meanwhile, vitamin D supplementation should be strongly advised for people likely to be deficient.
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Affiliation(s)
- J. M. Rhodes
- From theDepartment of Cellular and Molecular PhysiologyInstitute of Translational MedicineUniversity of LiverpoolLiverpoolUK
| | - S. Subramanian
- From theDepartment of Cellular and Molecular PhysiologyInstitute of Translational MedicineUniversity of LiverpoolLiverpoolUK
| | - E. Laird
- The Irish Longitudinal Study on AgeingSchool of MedicineTrinity College DublinDublinIreland
| | - G. Griffin
- Infectious Diseases and MedicineSt George’sUniversity of LondonLondonUK
| | - R. A. Kenny
- Department of Medical GerontologyMercers Institute for AgeingSt James HospitalDublin 8Ireland
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6
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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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7
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Yuan C, Song M, Zhang Y, Wolpin BM, Meyerhardt JA, Ogino S, Hollis BW, Chan AT, Fuchs CS, Wu K, Wang M, Smith-Warner SA, Giovannucci EL, Ng K. Prediagnostic Circulating Concentrations of Vitamin D Binding Protein and Survival among Patients with Colorectal Cancer. Cancer Epidemiol Biomarkers Prev 2020; 29:2323-2331. [PMID: 32917664 DOI: 10.1158/1055-9965.epi-20-0291] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/28/2020] [Accepted: 08/24/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Higher total 25-hydroxyvitamin D [25(OH)D] levels are associated with improved survival among patients with colorectal cancer, but the relationships between circulating vitamin D binding protein (VDBP), and bioavailable or free 25(OH)D, and colorectal cancer survival remain unknown. METHODS We examined the associations between prediagnostic plasma levels of vitamin D-related markers and survival among 603 White participants diagnosed with colorectal cancer from two prospective U.S. cohorts. Plasma VDBP and total 25(OH)D were directly measured, while bioavailable and free 25(OH)D was calculated using a validated formula on the basis of total 25(OH)D, VDBP, and albumin levels. Cox proportional hazards regression was used to estimate HRs for overall and colorectal cancer-specific mortality, with adjustment for other prognostic markers and potential confounders. RESULTS Higher VDBP levels were associated with improved overall (P trend = 0.001) and colorectal cancer-specific survival (P trend = 0.02). Compared with patients in the lowest quartile, those in the highest quartile of VDBP had a multivariate HR of 0.58 [95% confidence interval (CI), 0.41-0.80] for overall mortality and 0.58 (95% CI, 0.37-0.91) for colorectal cancer-specific mortality. The results remained similar after further adjustment for total 25(OH)D levels. In contrast, neither bioavailable nor free 25(OH)D levels were associated with overall or colorectal cancer-specific mortality (all P trend > 0.15). CONCLUSIONS Prediagnostic circulating concentrations of VDBP were positively associated with survival among patients with colorectal cancer. IMPACT The clinical utility of VDBP as a prognostic marker warrants further exploration, as well as research into underlying mechanisms of action.
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Affiliation(s)
- Chen Yuan
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts. .,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Mingyang Song
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Clinical and Translational Epidemiology Unit and Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Yin Zhang
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts.,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Brian M Wolpin
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts
| | - Jeffrey A Meyerhardt
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts
| | - Shuji Ogino
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Program in MPE Molecular Pathological Epidemiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Department of Oncologic Pathology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Bruce W Hollis
- Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina
| | - Andrew T Chan
- Clinical and Translational Epidemiology Unit and Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.,Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Charles S Fuchs
- Yale Cancer Center, Smilow Cancer Hospital, New Haven, Connecticut
| | - Kana Wu
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Molin Wang
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Stephanie A Smith-Warner
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Edward L Giovannucci
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Kimmie Ng
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts
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8
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Henderson CM, Fink SL, Bassyouni H, Argiropoulos B, Brown L, Laha TJ, Jackson KJ, Lewkonia R, Ferreira P, Hoofnagle AN, Marcadier JL. Vitamin D-Binding Protein Deficiency and Homozygous Deletion of the GC Gene. N Engl J Med 2019; 380:1150-1157. [PMID: 30893535 PMCID: PMC7898410 DOI: 10.1056/nejmoa1807841] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A 58-year-old woman with debilitating ankylosing spondylitis who was born to consanguineous parents was found to have an apparent severe vitamin D deficiency that did not respond to supplementation. Liquid chromatography-tandem mass spectrometry showed the absence of circulating vitamin D-binding protein, and chromosomal microarray confirmed a homozygous deletion of the group-specific component (GC) gene that encodes the protein. Congenital absence of vitamin D-binding protein resulted in normocalcemia and a relatively mild disruption of bone metabolism, in this case complicated by severe autoimmune disease. (Funded by the National Institutes of Health and the University of Washington.).
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Affiliation(s)
- Clark M Henderson
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
| | - Susan L Fink
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
| | - Hanan Bassyouni
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
| | - Bob Argiropoulos
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
| | - Lindsay Brown
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
| | - Thomas J Laha
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
| | - Konner J Jackson
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
| | - Raymond Lewkonia
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
| | - Patrick Ferreira
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
| | - Andrew N Hoofnagle
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
| | - Julien L Marcadier
- From the Departments of Laboratory Medicine (C.M.H., S.L.F., T.J.L., K.J.J., A.N.H.) and Medicine (A.N.H.) and the Kidney Research Institute (A.N.H.), University of Washington, Seattle; and the Department of Endocrinology and Metabolism (H.B.) and the Alberta Children's Hospital Research Institute (B.A.), University of Calgary, and the Division of Medical Genetics, Alberta Children's Hospital (R.L., P.F., J.L.M.), Calgary, and the Department of Pathology, Children's & Women's Health Centre of British Columbia, Vancouver (L.B.) - all in Canada
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9
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Chun RF, Shieh A, Gottlieb C, Yacoubian V, Wang J, Hewison M, Adams JS. Vitamin D Binding Protein and the Biological Activity of Vitamin D. Front Endocrinol (Lausanne) 2019; 10:718. [PMID: 31708871 PMCID: PMC6821678 DOI: 10.3389/fendo.2019.00718] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 10/04/2019] [Indexed: 12/15/2022] Open
Abstract
Vitamin D has a long-established role in bone health. In the last two decades, there has been a dramatic resurgence in research interest in vitamin D due to studies that have shown its possible benefits for non-skeletal health. Underpinning the renewed interest in vitamin D was the identification of the vital role of intracrine or localized, tissue-specific, conversion of inactive pro-hormone 25-hydroxyvitamin D [25(OH)D] to active 1,25-dihydroxyvitamin D [1,25(OH)2D]. This intracrine mechanism is the likely driving force behind vitamin D action resulting in positive effects on human health. To fully capture the effect of this localized, tissue-specific conversion to 1,25(OH)2D, adequate 25(OH)D would be required. As such, low serum concentrations of 25(OH)D would compromise intracrine generation of 1,25(OH)2D within target tissues. Consistent with this is the observation that all adverse human health consequences of vitamin D deficiency are associated with a low serum 25(OH)D level and not with low 1,25(OH)2D concentrations. Thus, clinical investigators have sought to define what concentration of serum 25(OH)D constitutes adequate vitamin D status. However, since 25(OH)D is transported in serum bound primarily to vitamin D binding protein (DBP) and secondarily to albumin, is the total 25(OH)D (bound plus free) or the unbound free 25(OH)D the crucial determinant of the non-classical actions of vitamin D? While DBP-bound-25(OH)D is important for renal handling of 25(OH)D and endocrine synthesis of 1,25(OH)2D, how does DBP impact extra-renal synthesis of 1,25(OH)2D and subsequent 1,25(OH)2D actions? Are their pathophysiological contexts where total 25(OH)D and free 25(OH)D would diverge in value as a marker of vitamin D status? This review aims to introduce and discuss the concept of free 25(OH)D, the molecular biology and biochemistry of vitamin D and DBP that provides the context for free 25(OH)D, and surveys in vitro, animal, and human studies taking free 25(OH)D into consideration.
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Affiliation(s)
- Rene F. Chun
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
- *Correspondence: Rene F. Chun
| | - Albert Shieh
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Carter Gottlieb
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Vahe Yacoubian
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Jeffrey Wang
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Martin Hewison
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - John S. Adams
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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Bouillon R, Schuit F, Antonio L, Rastinejad F. Vitamin D Binding Protein: A Historic Overview. Front Endocrinol (Lausanne) 2019; 10:910. [PMID: 31998239 PMCID: PMC6965021 DOI: 10.3389/fendo.2019.00910] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 12/13/2019] [Indexed: 02/06/2023] Open
Abstract
Vitamin D and all its metabolites are bound to a specific vitamin D binding protein, DBP. This protein was originally first discovered by its worldwide polymorphism and called Group-specific Component (GC). We now know that DBP and GC are the same protein and appeared early in the evolution of vertebrates. DBP is genetically the oldest member of the albuminoid family (including albumin, α-fetoprotein and afamin, all involved in transport of fatty acids or hormones). DBP has a single binding site for all vitamin D metabolites and has a high affinity for 25OHD and 1,25(OH)2D, thereby creating a large pool of circulating 25OHD, which prevents rapid vitamin D deficiency. DBP of higher vertebrates (not amphibians or reptiles) binds with very high affinity actin, thereby preventing the formation of polymeric actin fibrils in the circulation after tissue damage. Megalin is a cargo receptor and is together with cubilin needed to reabsorb DBP or the DBP-25OHD complex, thereby preventing the urinary loss of these proteins and 25OHD. The total concentrations of 25OHD and 1,25(OH)2D in DBP null mice or humans are extremely low but calcium and bone homeostasis remain normal. This is the strongest argument for claiming that the "free hormone hypothesis" also applies to the vitamin D hormone, 1,25(OH)2D. DBP also transports fatty acids, and can play a role in the immune system. DBP is genetically very polymorphic with three frequent alleles (DBP/GC 1f, 1s, and 2) but in total more than 120 different variants but its health consequences, if any, are not understood. A standardization of DBP assays is essential to further explore the role of DBP in physiology and diseases.
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Affiliation(s)
- Roger Bouillon
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
- *Correspondence: Roger Bouillon
| | - Frans Schuit
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Leen Antonio
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
- Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium
| | - Fraydoon Rastinejad
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford, United Kingdom
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11
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Low 25-hydroxyvitamin D levels are more prevalent in Canadians of South Asian than European ancestry inhabiting the National Capital Region of Canada. PLoS One 2018; 13:e0207429. [PMID: 30540776 PMCID: PMC6291105 DOI: 10.1371/journal.pone.0207429] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/31/2018] [Indexed: 11/19/2022] Open
Abstract
The US Institute of Medicine defined serum 25-hydroxyvitamin D (25OHD) cut point values of 30 nmol/L and 40 nmol/L were used to assess the vitamin D status of South Asian and European Canadians of self-identified ancestry living in the National Capital Region of Canada. Serum 25OHD values were measured in the spring and fall of 2012 to represent status during the winter and summer months, respectively. A total of 1238 measurements were obtained from 669 participants (49% South Asian ancestry): some participants were measured only once (spring or fall). Median 25OHD values were significantly higher in participants of European ancestry: 70.8 nmol/L (68.1, 73.5; 95% CI) versus South Asian ancestry: 42.7 nmol/L (40.5, 45.0; P<0.001). Spring vs. fall differences were small for each ethnic group and significant only for those of European ancestry (2.9, CI: 1.0–4.9 nmol/L; P = 0.01). Among participants of South Asian ancestry, 27.3% (fall) and 29.1% (spring) of females had values <40 nmol/L while the percentages for males were considerably higher (36.5% and 44.2%, respectively). The corresponding values for participants of European ancestry were ≤10%, showing that the South Asian participants were less likely to achieve the 25OHD concentrations established by the IOM for optimum bone health. Investigation of the factors related to serum 25OHD levels showed that supplement intake and ethnic background were associated with the biggest differences. Skin color was not a major factor, suggesting that genetic factors are responsible for the observed differences between participants of different ethnic backgrounds.
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Yuan C, Shui IM, Wilson KM, Stampfer MJ, Mucci LA, Giovannucci EL. Circulating 25-hydroxyvitamin D, vitamin D binding protein and risk of advanced and lethal prostate cancer. Int J Cancer 2018; 144:2401-2407. [PMID: 30411792 DOI: 10.1002/ijc.31966] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/24/2018] [Accepted: 10/10/2018] [Indexed: 11/11/2022]
Abstract
We previously found that higher total 25-hydroxyvitamin D [25(OH)D] levels were associated with lower risk of lethal prostate cancer. However, the relationships of bioavailable 25(OH)D and vitamin D binding protein (VDBP) with risk of advanced and lethal prostate cancer are unclear. In a prospective case-control study of 156 pairs of advanced prostate cancer cases and controls, we directly measured prediagnostic circulating 25(OH)D and VDBP and calculated bioavailable 25(OH)D using a validated formula. We examined the association of bioavailable 25(OH)D and VDBP levels with risk of advanced and lethal prostate cancer and whether total 25(OH)D levels interacted with VDBP levels to affect the risk. Conditional logistic models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Compared to total 25(OH)D (ptrend = 0.02), bioavailable 25(OH)D levels were not more strongly associated with risk of advanced prostate cancer (ptrend = 0.14). Although VDBP levels were not associated with risk of advanced prostate cancer (ptrend = 0.16), we observed an interaction between total 25(OH)D levels and VDBP levels in relation to risk of advanced prostate cancer (pinteraction = 0.03). Compared to those with total 25(OH)D levels below the median and VDBP levels above the median (at highest risk), men with both levels above the median had a multivariable-adjusted OR of 0.31 (95% CI, 0.15-0.65) for advanced prostate cancer. We observed similar results when we restricted the analyses to 116 lethal prostate cancer cases and their controls. Our data suggest that VDBP levels may modify the association between total 25(OH)D levels and risk of advanced and lethal prostate cancer.
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Affiliation(s)
- Chen Yuan
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA.,Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA
| | - Irene M Shui
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA
| | - Kathryn M Wilson
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA.,Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA
| | - Meir J Stampfer
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA.,Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA.,Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Lorelei A Mucci
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA.,Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Edward L Giovannucci
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA.,Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA.,Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
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13
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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
- Correspondence and Reprint Requests: Janice B. Schwartz, MD, Department of Medicine, University of California, San Francisco, Box 1265, 3333 California Street, San Francisco, California 94143-1265. E-mail:
| | | | - 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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14
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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: 132] [Impact Index Per Article: 22.0] [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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Abstract
Twin studies indicate that genetic factors may explain about 50% of the variation of serum 25-hydroxyvitamin D (25OHD). Polymorphisms of 3 genes, delta-7-sterol-reductase, CYP2R1, and DBP/GC (and maybe CYP24A1) combined, can explain about 5% to 10% of the variation in serum 25OHD. These polymorphisms are found in nearly all populations. The variation in serum 25OHD found in different areas and populations in the world is mainly due to environmental and lifestyle factors, not truly dependent on racial differences. One genetic variant of DBP, (GC2), is associated with a modest (∼10%) decrease in serum DBP and 25OHD concentrations for unexplained reasons.
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Affiliation(s)
- Roger Bouillon
- Clinical and Experimental Endocrinology, KU Leuven, Herestraat 49 ON1 Box 902, Leuven 3000, Belgium.
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16
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Bikle D, Bouillon R, Thadhani R, Schoenmakers I. Vitamin D metabolites in captivity? Should we measure free or total 25(OH)D to assess vitamin D status? J Steroid Biochem Mol Biol 2017; 173:105-116. [PMID: 28093353 PMCID: PMC9005158 DOI: 10.1016/j.jsbmb.2017.01.007] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 12/31/2016] [Accepted: 01/10/2017] [Indexed: 01/03/2023]
Abstract
There is general consensus that serum 25(OH)D is the best biochemical marker for nutritional vitamin D status. Whether free 25(OH)D would be a better marker than total 25(OH)D is so far unclear. Free 25(OH)D can either be calculated based on the measurement of the serum concentrations of total 25(OH)D, vitamin D-binding protein (DBP), albumin, and the affinity between 25(OH)D and its binding proteins in physiological situations. Free 25(OH)D can also be measured directly by equilibrium dialysis, ultrafitration or immunoassays. During the vitamin D workshop held in Boston in March 2016, a debate was organized about the measurements and clinical value of free 25(OH)D, and this debate is summarized in the present manuscript. Overall there is consensus that most cells apart from the renal tubular cells are exposed to free rather than to total 25(OH)D. Therefore free 25(OH)D may be highly relevant for the local production and action of 1,25(OH)2D. During the debate it became clear that there is a need for standardization of measurements of serum DBP and of direct measurements of free 25(OH)D. There seems to be very limited genetic or racial differences in DBP concentrations or (probably) in the affinity of DBP for its major ligands. Therefore, free 25(OH)D is strongly correlated to total 25(OH)D in most normal populations. Appropriate studies are needed to define the clinical implications of free rather than total 25(OH)D in normal subjects and in disease states. Special attention is needed for such studies in cases of abnormal DBP concentrations or when one could expect changes in its affinity for its ligands.
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Affiliation(s)
- Daniel Bikle
- VA Medical Center and University of California San Francisco, San Francisco, CA 94158, USA.
| | - Roger Bouillon
- Clinical & Experimental Endocrinology, KULeuven, Herestraat 49 ON1 Box 902, 3000 Leuven, Belgium.
| | - Ravi Thadhani
- Division of Nephrology, Massachusetts General Hospital, Boston, USA.
| | - Inez Schoenmakers
- Medical Research Council (MRC), Human Nutrition Research, Elsie Widdowson Laboratory, 120 Fulbourn Road, CB1 9NL Cambridge, UK; Department of Medicine, Faculty of Medicine and Health Sciences, University of East Anglia, NR4 7TJ Norwich, UK.
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Schoenmakers I, Jones KS. Letter to the Editor: The Effect of Genetic Factors on the Response to Vitamin D Supplementation May Be Mediated by Vitamin D-Binding Protein Concentrations. J Clin Endocrinol Metab 2017; 102:2562-2563. [PMID: 28899076 PMCID: PMC5505207 DOI: 10.1210/jc.2017-00666] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 04/21/2017] [Indexed: 11/19/2022]
Affiliation(s)
- Inez Schoenmakers
- Department of Medicine, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Kerry S Jones
- MRC Elsie Widdowson Laboratory, Cambridge CB1 9NL, United Kingdom
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Canoa P, Rivadulla ML, Popplewell J, van Oosten R, Gómez G, Fall Y. Use of surface plasmon resonance in the binding study of vitamin D, metabolites and analogues with vitamin D binding protein. Anal Bioanal Chem 2017; 409:2547-2558. [DOI: 10.1007/s00216-017-0200-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 12/21/2016] [Accepted: 01/10/2017] [Indexed: 12/28/2022]
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Hauenschild T, Reichenwallner J, Enkelmann V, Hinderberger D. Characterizing Active Pharmaceutical Ingredient Binding to Human Serum Albumin by Spin-Labeling and EPR Spectroscopy. Chemistry 2016; 22:12825-38. [DOI: 10.1002/chem.201601810] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Till Hauenschild
- Martin-Luther-Universität Halle-Wittenberg; Institute of Chemistry; Von-Danckelmann-Platz 4 06120 Halle (Saale) Germany
| | - Jörg Reichenwallner
- Martin-Luther-Universität Halle-Wittenberg; Institute of Chemistry; Von-Danckelmann-Platz 4 06120 Halle (Saale) Germany
| | - Volker Enkelmann
- Max Planck Institute for Polymer Research; Ackermannweg 10 55128 Mainz Germany
| | - Dariush Hinderberger
- Martin-Luther-Universität Halle-Wittenberg; Institute of Chemistry; Von-Danckelmann-Platz 4 06120 Halle (Saale) Germany
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Bouillon R. Free or Total 25OHD as Marker for Vitamin D Status? J Bone Miner Res 2016; 31:1124-7. [PMID: 27172227 DOI: 10.1002/jbmr.2871] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 05/06/2016] [Accepted: 05/09/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Roger Bouillon
- Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
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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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Berg AH, Powe CE, Evans MK, Wenger J, Ortiz G, Zonderman AB, Suntharalingam P, Lucchesi K, Powe NR, Karumanchi SA, Thadhani RI. 24,25-Dihydroxyvitamin d3 and vitamin D status of community-dwelling black and white Americans. Clin Chem 2015; 61:877-84. [PMID: 25922442 DOI: 10.1373/clinchem.2015.240051] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 03/26/2015] [Indexed: 12/27/2022]
Abstract
BACKGROUND 24,25-Dihydroxyvitamin D [24,25(OH)2D] is a metabolite of 25-hydroxyvitamin D (25D). Blacks frequently have low total 25D without manifestations of vitamin D deficiency, suggesting that total serum 25D may incorrectly reflect vitamin D status in different racial groups. The ratio of serum 24,25(OH)2D to 25D [vitamin D metabolite ratio (VMR)] represents a new candidate biomarker for vitamin D status. METHODS We measured 24,25(OH)2D3 and 25D3 by mass spectrometry in a random community cohort of black (n = 212) and white (n = 164) Americans to evaluate VMR as a marker for vitamin D status. We measured parathyroid hormone concentrations by immunoassay to compare VMR and 25D3 against a physiological indicator of vitamin D deficiency. RESULTS Serum 24,25(OH)2D3 strongly correlated with 25D3 in both black and white study participants (r = 0.90, P < 0.001 and r = 0.86, P < 0.001 respectively). Blacks had lower mean 25D3 than whites [17.0 (7.8) vs 27.5 (11.3) ng/mL; 42.4 (19.5) vs 68.6 (28.2) nmol/L, P < 0.001] and lower mean 24,25(OH)2D3 [2.1 (1.3) vs 3.6 (2.0) ng/mL; 5.1 (3.1) vs 8.7 (4.8) nmol/L, P < 0.001]. In contrast to total 25D3 concentrations, mean VMR values were similar in blacks and whites [11.9 (4.0) vs 12.5 (3.4), P = 0.16, respectively] and were negatively correlated with parathyroid hormone concentrations in both races (rs = -0.26, P < 0.001, and rs = -0.25, P < 0.001, respectively). CONCLUSIONS Our results provide further evidence that measurement of total 25D for assessment of vitamin D status in patients of African descent deserves reevaluation and suggest that alternative measures such as VMR should be considered.
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Affiliation(s)
- Anders H Berg
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA;
| | - Camille E Powe
- Division of Endocrinology, Massachusetts General Hospital, Boston, MA
| | - Michele K Evans
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, National Institutes of Health, Baltimore MD
| | - Julia Wenger
- Division of Nephrology, Massachusetts General Hospital, Boston, MA
| | - Guillermo Ortiz
- Division of Nephrology, Massachusetts General Hospital, Boston, MA
| | - Alan B Zonderman
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, National Institutes of Health, Baltimore MD
| | | | - Kathryn Lucchesi
- Division of Nephrology, Massachusetts General Hospital, Boston, MA
| | - Neil R Powe
- Department of Medicine, San Francisco General Hospital and University of California, San Francisco, CA
| | - S Ananth Karumanchi
- Division of Nephrology, Beth Israel Deaconess Medical Center, Boston, MA; Howard Hughes Medical Institute, Chevy Chase, MD
| | - Ravi I Thadhani
- Division of Nephrology, Massachusetts General Hospital, Boston, MA;
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23
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Ahmed MS, Shoker A. Vitamin D Metabolites; Protective versus Toxic Properties: Molecular and Cellular Perspectives. ACTA ACUST UNITED AC 2014. [DOI: 10.4081/nr.2010.e5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Vitamin D plays an essential role in bone metabolism. The discovery that the vitamin D receptor (VDR), a member of the nuclear receptor superfamily, is expressed in most tissues led researchers to investigate other biological actions of vitamin D. These effects were found to include anti-inflammatory effects and anti-atherogenesis, decreased renin activity and biosynthesis, induction of cell differentiation, inhibition of cell growth, and immunomodulation. In spite of the plethora of evidence on the protective effects of vitamin D, the reports on its intoxication still are considerably few. Therefore, in this review we aim to summarize the molecular and cellular bases of the protect-ive and toxic vitamin D actions that are mediated mostly by VDR. This review will also shed light on vitamin D metabolites other than the active metabolite calcitriol and particularly 25-hydroxy vitamin D (25(OH)D), putting emphasis on its magnifying role in vitamin D intoxication. One of the important themes we discuss is defining serum levels of beneficial or toxic effects of other exogenous vitamin D administration and its impact on 25(OH)D serum levels in animals and human subjects.
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Affiliation(s)
- Mohamed S. Ahmed
- Department of Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ahmed Shoker
- Department of Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, SK, Canada
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24
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Curtis KM, Aenlle KK, Roos BA, Howard GA. 24R,25-dihydroxyvitamin D3 promotes the osteoblastic differentiation of human mesenchymal stem cells. Mol Endocrinol 2014; 28:644-58. [PMID: 24597546 DOI: 10.1210/me.2013-1241] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Although 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] is considered the most biologically active vitamin D3 metabolite, the vitamin D3 prohormone, 25-hydroxyvitamin D3 [25(OH)D3], is metabolized into other forms, including 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3]. Herein we show that 24R,25(OH)2D3 is fundamental for osteoblastic differentiation of human mesenchymal stem cells (hMSCs). Our approach involved analyses of cell proliferation, alkaline phosphatase activity, and pro-osteogenic genes (collagen 1A1, osteocalcin, vitamin D receptor [VDR], vitamin D3-hydroxylating enzymes [cytochrome P450 hydroxylases: CYP2R1, CYP27A1, CYP27B1 and CYP24A1]) and assessment of Ca(2+) mineralization of extracellular matrix. 24R,25(OH)2D3 inhibited hMSC proliferation, decreased 1α-hydroxylase (CYP27B) expression, thereby reducing the ability of hMSCs to convert 25(OH)D3 to 1α,25(OH)2D3, and promoted osteoblastic differentiation through increased alkaline phosphatase activity and Ca(2+) mineralization. 24R,25(OH)2D3 decreased expression of the 1α,25(OH)2D3 receptor, VDR. 24R,25(OH)2D3 but not 1α,25(OH)2D3 induced Ca(2+) mineralization dependent on the absence of the glucocorticoid analog, dexamethasone. To elucidate the mechanism(s) for dexamethasone-independent 1α,25(OH)2D3 inhibition/24R,25(OH)2D3 induction of Ca(2+) mineralization, we demonstrated that 1α,25(OH)2D3 increased whereas 24R,25(OH)2D3 decreased reactive oxygen species (ROS) production. 25(OH)D3 also decreased ROS production, potentially by conversion to 24R,25(OH)2D3. Upon inhibition of the vitamin D3-metabolizing enzymes (cytochrome P450s), 25(OH)D3 increased ROS production, potentially due to its known (low) affinity for VDR. We hypothesize that vitamin D3 actions on osteoblastic differentiation involve a regulatory relationship between 24R,25(OH)2D3 and 1α,25(OH)2D3. These results implicate 24R,25(OH)2D3 as a key player during hMSC maturation and bone development and support the concept that 24R,25(OH)2D3 has a bioactive role in the vitamin D3 endocrine system.
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Affiliation(s)
- Kevin M Curtis
- Geriatric Research, Education, and Clinical Center and Research Service (K.M.C., K.K.A., B.A.R., G.A.H.), Bruce W. Carter Veterans Affairs Medical Center, Miami, Florida 33125; and Departments of Biochemistry and Molecular Biology (K.M.C., G.A.H.), Medicine (B.A.R., G.A.H.), and Neurology (B.A.R.), University of Miami Miller School of Medicine, Miami, Florida 33101
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25
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Briggs ADM, Kuan V, Greiller CL, Maclaughlin BD, Ramachandran M, Harris T, Timms PM, Venton TR, Vieth R, Norman AW, Griffiths CJ, Martineau AR. Longitudinal study of vitamin D metabolites after long bone fracture. J Bone Miner Res 2013; 28:1301-7. [PMID: 23281057 DOI: 10.1002/jbmr.1855] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 11/16/2012] [Accepted: 12/05/2012] [Indexed: 01/04/2023]
Abstract
Animal models suggest a key role for dihydroxylated vitamin D metabolites in fracture healing, as evidenced by increases in serum concentration of 24R,25-dihydroxyvitamin D (24R,25[OH]₂D) after long bone fracture. Human studies investigating the kinetics of serum concentrations of 24R,25[OH]₂D, 1,25-dihydroxyvitamin D (1,25[OH]₂D) and their parent metabolite 25-hydroxyvitamin D (25[OH]D) are lacking. We, therefore, conducted a longitudinal study to determine whether total, free, or bioavailable concentrations of these vitamin D metabolites fluctuate in humans after long bone fracture. Twenty-eight patients with cross-shaft (diaphyseal) long bone fracture presenting to an emergency department in London, UK, were studied. Serum concentrations of 25(OH)D, 24R,25(OH)₂D, 1,25(OH)₂D, vitamin D binding protein, albumin, and calcium were determined within 48 hours of fracture and again at 1 and 6 weeks postfracture. Concentrations of free and bioavailable vitamin D metabolites were calculated using standard equations. No changes in mean serum concentrations of 25(OH)D or 24R,25(OH)₂D were seen at either follow-up time point versus baseline. In contrast, mean serum 1,25(OH)2 D concentration declined by 21% over the course of the study, from 68.5 pmol/L at baseline to 54.1 pmol/L at 6 weeks (p < 0.05). This decline was associated with an increase in mean serum corrected calcium concentration, from 2.32 mmol/L at baseline to 2.40 mmol/L at 1 week (p < 0.001) that was maintained at 6 weeks. No changes in free or bioavailable concentrations of any vitamin D metabolite investigated were seen over the course of the study. We conclude that serum 1,25(OH)₂D concentration declines after long bone fracture in humans but that the serum 24R,25(OH)₂D concentration does not fluctuate. The latter finding contrasts with those of animal models reporting increases in serum 24R,25(OH)₂D concentration after long bone fracture.
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Affiliation(s)
- Adam D M Briggs
- Centre for Primary Care and Public Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom, USA
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26
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Garg M, Lubel JS, Sparrow MP, Holt SG, Gibson PR. Review article: vitamin D and inflammatory bowel disease--established concepts and future directions. Aliment Pharmacol Ther 2012; 36:324-44. [PMID: 22686333 DOI: 10.1111/j.1365-2036.2012.05181.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 05/11/2012] [Accepted: 05/25/2012] [Indexed: 02/06/2023]
Abstract
BACKGROUND Understanding of the role of vitamin D in health and disease has increased markedly in the past decade, with its involvement extending well beyond traditional roles in calcium and phosphate homeostasis and musculoskeletal health. This conceptual expansion has been underpinned by identification and exploration of components of this axis including vitamin D-binding protein, key enzymes and receptors in multiple cell types, and a greater recognition of nonclassical autocrine and paracrine effects. Its influence in IBD remains uncertain. AIM To review the role of vitamin D in bone health, immune regulation and cancer prevention in IBD, and to outline practical issues and limitations of its use. METHODS An extensive online literature review including PubMed and Medline. RESULTS In patients with IBD, the vitamin D axis provides an important and often underutilised pathway to preserving bone health. Furthermore, an exciting body of clinical and basic science research demonstrates that these pathways may have an integral part to play in regulation of the immune response in IBD, through effects on the intestinal barrier, antigen presenting cells and adaptive T cells. The possibility of chemoprevention requires further study. The optimal target level of 25-hydroxy vitamin D in patients with IBD is currently uncertain, as is the best therapeutic modality. CONCLUSIONS Study of vitamin D pathways may result in the development of relatively inexpensive therapeutic options to optimise patient outcomes. Further prospective clinical research is required to address efficacy and long-term safety.
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Affiliation(s)
- M Garg
- Department of Gastroenterology & Hepatology, Eastern Health, Box Hill, Vic., Australia.
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27
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Cytochromes P450 are essential players in the vitamin D signaling system. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1814:186-99. [PMID: 20619365 DOI: 10.1016/j.bbapap.2010.06.022] [Citation(s) in RCA: 192] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 06/15/2010] [Accepted: 06/28/2010] [Indexed: 12/13/2022]
Abstract
From earliest development on, the vitamin D receptor (VDR) is expressed in most cells of the mammalian body. The VDR is a nuclear, ligand-induced transcription factor that regulates in complex with hormonally active vitamin D the expression of more than 900 genes involved in a wide array of physiological functions (e.g. calcium homeostasis, growth control, differentiation, cognition, immune response, etc.). Accordingly, severe health problems are associated to vitamin deficiencies. Synthesis of the major active form 1α,25(OH)₂D₃ from vitamin D and subsequent metabolism are exclusively controlled by specific P450-forms. Synthesis, a two-step process, starts with a 25-hydroxylation primarily by CYP2R1 (CYP27A1, CYP2J2, and CYP3A4 may also contribute) and a subsequent 1α-hydroxylation via CYP27B1. Circulating in the bloodstream, 1α,25(OH)₂D₃ acts at sites of VDR expression (target sites) in an endocrine way. However, it is also capable of autocrine/paracrine functions since various target tissues are fully competent in 1α,25(OH)₂D₃ synthesis, as illustrated by three examples. 1α,25(OH)₂D₃ levels are short-lived: the hormone upregulates its rapid metabolism by CYP24A1 that attacks repeatedly the vitamin D C₂₀₋₂₇ side chain, thereby producing a complex cascade of transient metabolites with increasing polarity. Most of these metabolites still retain 1α,25(OH)₂D₃-like activities on the VDR, contributing to the overall effect that is commonly attributed to 1α,25(OH)₂D₃. As selective inhibitors of CYP24A1 increase the lifetime and thereby the function of vitamin D metabolites, they will help exploring whether and which intrinsic activities distinct metabolites possess. It appears likely that this strategy may unmask important regulators of new functions.
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28
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Synthesis of C-11 linked active ester derivatives of vitamin D3 and their conjugations to 42-residue helix–loop–helix peptides. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.04.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
Although researchers first identified the fat-soluble vitamin cholecalciferol almost a century ago and studies have now largely elucidated the transcriptional mechanism of action of its hormonal form, 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], we know surprisingly little about mechanisms of vitamin D toxicity. The lipophilic nature of vitamin D explains its adipose tissue distribution and its slow turnover in the body (half-life approximately 2 mo). Its main transported metabolite, 25-hydroxyvitamin D(3) [25(OH)D(3)], shows a half-life of approximately 15 d and circulates at a concentration of 25-200 nmol/L, whereas the hormone 1alpha,25(OH)(2)D(3) has a half-life of approximately 15 h. Animal experiments involving vitamin D(3) intoxication have established that 25(OH)D(3) can reach concentrations up to 2.5 mumol/L, at which it is accompanied by hypercalcemia and other pathological sequelae resulting from a high Ca/PO(4) product. The rise in 25(OH)D(3) is accompanied by elevations of its precursor, vitamin D(3), as well as by rises in many of its dihydroxy- metabolites [24,25(OH)(2)D(3); 25,26(OH)(2)D(3); and 25(OH)D(3)-26,23-lactone] but not 1alpha,25(OH)(2)D(3). Early assumptions that 1alpha,25(OH)(2)D(3) might cause hypercalcemia in vitamin D toxicity have been replaced by the theories that 25(OH)D(3) at pharmacologic concentrations can overcome vitamin D receptor affinity disadvantages to directly stimulate transcription or that total vitamin D metabolite concentrations displace 1alpha,25(OH)(2)D from vitamin D binding, increasing its free concentration and thus increasing gene transcription. Occasional anecdotal reports from humans intoxicated with vitamin D appear to support the latter mechanism. Although current data support the viewpoint that the biomarker plasma 25(OH)D concentration must rise above 750 nmol/L to produce vitamin D toxicity, the more prudent upper limit of 250 nmol/L might be retained to ensure a wide safety margin.
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Affiliation(s)
- Glenville Jones
- Departments of Biochemistry and Medicine, Queen's University, Kingston, Ontario, Canada.
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30
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Chan FK, Koberle LM, Thys-Jacobs S, Bilezikian JP. Differential diagnosis, causes, and management of hypercalcemia. Curr Probl Surg 1997; 34:445-523. [PMID: 9186232 DOI: 10.1016/s0011-3840(97)80008-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- F K Chan
- College of Physicians and Surgeons Columbia University, New York, New York, USA
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31
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Abstract
Vitamin D is a complex of secosteroids that must undergo metabolic alterations to reach optimal biological activity. The parent compounds 1) ergocalciferol (D2) and 2) cholecalciferol (D3) can be synthesized in the leaves of many plants or in the skin of most animals, respectively. Transport of vitamin D steroids after absorption is associated with vitamin D binding proteins (DBP). In general, the relative binding affinities of the vitamin D steroids are: 25-hydroxy vitamin D3 [25-(OH)D3] = 24,25-dihydroxy vitamin D3 [24,25-(OH)2D3] = 25,26-dihydroxy vitamin D3 [25,26-(OH)2D3] > 25-hydroxy vitamin D2 (25-(OH)D2) > 1,25-dihydroxy vitamin D3 [1,25-(OH)2D3] > vitamin D3. The DBP in poultry does not bind D2 forms effectively, and therefore poultry can not use this form of vitamin D adequately. The concentration of 25-(OH)D3 in blood seems to be well correlated with dietary vitamin D intake or exposure to ultraviolet light. The 1 alpha hydroxylase enzyme in the kidney is subject to negative feedback regulation and is critical for formation of the active metabolite 1,25-(OH)2D3. The intracellular vitamin D receptor (VDR) specifically binds 1,25-(OH)2D3 and is necessary for cellular action. Increased levels of two to three orders of magnitude are required for 25-(OH)D3 to compete with 1,25-(OH)2D3 for binding on VDR. Feeding studies with 25-(OH)D3 suggest it has nearly twice the activity of vitamin D3. Hatchability studies have shown that 25-(OH)D3 supports good fertility and hatchability, whereas hens fed only 1,25-(OH)2D3 did not have normal hatchability. Likewise, 1,25-(OH)2D3 seems to reach toxic levels at dietary concentrations only two to three times optimal dietary levels whereas feeding 25-(OH)D3 for extended periods at levels 8 to 10 times requirement seems to have no adverse effects. It seems that 25-(OH)D3 is the most active metabolite of vitamin D3, ultimately capable of supporting both cellular functions and embryonic development in chickens and turkeys when fed as the sole source of vitamin D3.
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Affiliation(s)
- J H Soares
- Department of Animal Sciences, University of Maryland, College Park 20742, USA
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32
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Arnaud J, Constans J. Affinity differences for vitamin D metabolites associated with the genetic isoforms of the human serum carrier protein (DBP). Hum Genet 1993; 92:183-8. [PMID: 8370586 DOI: 10.1007/bf00219689] [Citation(s) in RCA: 263] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Human vitamin D binding protein (DBP) displays considerable polymorphism with 120 described alleles. Among these, three alleles are frequently observed, Gc 1F (pI 4.94-4.84), Gc 1S (pI 4.95-4.85) and Gc 2 (pI 5.1). Differences between these genetic forms of the protein in affinity for vitamin D metabolites have been detected by electrophoretic methods. The constant affinity (Ka) values determined in this study confirm these differences. The affinities of six rare variants were also examine. Those of the DBP genetic forms to the vitamin D derivatives 25-OH-D3 and 1,25-(OH)2-D3 seem to be related to the isoelectric point of the proteins: a high affinity corresponding to a low isoelectric point. The Gc 1A9 and 1A11 mutants were associated with higher affinity for the vitamin D derivatives and the Gc 1C1 and 1C21 mutants were deficient.
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Affiliation(s)
- J Arnaud
- CRPG-CRNS, CHU Purpan, Toulouse, France
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33
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34
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Teegarden D, Meredith SC, Sitrin MD. Determination of the affinity of vitamin D metabolites to serum vitamin D binding protein using assay employing lipid-coated polystyrene beads. Anal Biochem 1991; 199:293-9. [PMID: 1667458 DOI: 10.1016/0003-2697(91)90104-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have developed an assay to measure the affinity of serum vitamin D binding protein for 25-hydroxyvitamin D3, 1,25-dihydroxyvitamin D3, and vitamin D3, using uniform diameter (6.4 microns) polystyrene beads coated with phosphatidylcholine and vitamin D metabolites as the vitamin D donor. The lipid metabolite coated beads have a solid core, and thus all of the vitamin D metabolites are on the bead surface from which transfer to protein occurs. After incubating these beads in neutral buffer for 3 h, essentially no 3H-labeled vitamin D metabolites desorb from this surface. Phosphatidylcholine/vitamin D metabolite-coated beads (1 microM vitamin D metabolite) were incubated with varying concentrations of serum vitamin D binding protein under conditions in which the bead surfaces were saturated with protein, but most of the protein was free in solution. After incubation, beads were rapidly centrifuged without disturbing the equilibrium of binding and vitamin D metabolite bound to sDBP in solution was assayed in the supernatant. All three vitamin D metabolites became bound to serum vitamin D binding protein, and after 10 min of incubation the transfer of the metabolites to serum vitamin D binding protein was time independent. The transfer followed a Langmuir isotherm, and the Kd for each metabolite binding to serum vitamin D binding protein was derived by nonlinear least-squares fit analysis. From this analysis the following values for the Kd were obtained: 5.59 x 10(-6) M, 25-hydroxyvitamin D; 9.45 x 10(-6) M, 1,25-dihydroxyvitamin D; and 9.17 x 10(-5) M, vitamin D. In conclusion, we have developed a method which avoids problems encountered in previous assays and allows the precise and convenient determination of binding affinities of vitamin D metabolites and serum vitamin D binding protein.
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Affiliation(s)
- D Teegarden
- Department of Foods and Nutrition, Purdue University, West Lafayette, IN 47907
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35
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Affiliation(s)
- R Vieth
- Department of Clinical Biochemistry, University of Toronto, Ontario, Canada
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36
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Braun A, Brandhofer A, Cleve H. Interaction of the vitamin D-binding protein (group-specific component) and its ligand 25-hydroxy-vitamin D3: binding differences of the various genetic types disclosed by isoelectric focusing. Electrophoresis 1990; 11:478-83. [PMID: 2394211 DOI: 10.1002/elps.1150110608] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The three common variants of the vitamin D binding protein, also known as group specific component (Gc), namely types 1S, 1F and 2, as well as some rare variants were studied by thin-layer polyacrylamide gel isoelectric focusing in a pH 4.5-5.4 carrier ampholyte generated pH gradient, additionally containing N-(2-acetamido)-2-aminoethanesulfonic acid (ACES). Prior to isoelectric focusing, whole serum or purified preparations of the vitamin D binding protein were incubated with 25-hydroxycholecalciferol at various ligand/protein ratios. Binding differences were found for the anodal and cathodal isoforms of Gc 1 variants and also for various allelic types. Isoforms with higher isoelectric points generally had a lower affinity for the ligand than the variants with lower isoelectric points.
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Affiliation(s)
- A Braun
- Institut für Anthropologie und Humangenetik der Universität München, Federal Republic of Germany
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37
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Mc Leod JF, Kowalski MA, Haddad JG. Interactions among Serum Vitamin D Binding Protein, Monomeric Actin, Profilin, and Profilactin. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(19)85080-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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38
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Boutin B, Galbraith RM, Arnaud P. Comparative affinity of the major genetic variants of human group-specific component (vitamin D-binding protein) for 25-(OH) vitamin D. JOURNAL OF STEROID BIOCHEMISTRY 1989; 32:59-63. [PMID: 2913402 DOI: 10.1016/0022-4731(89)90014-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Binding studies with [3H] 25-(OH) D3 were performed under a variety of conditions using Gc (Vitamin D-binding protein) purified from individuals displaying different phenotypes. No significant differences in affinity of binding were found between Gc1f, Gc1s and Gc2 allelle products in either homozygous or heterozygous individuals, nor between Gc1 anodal and Gc1 cathodal isotypes. Affinity was not significantly affected by different reaction temperatures (4, 22 or 37 degrees C), the presence or absence of Ca2+ ions, and binary and ternary interactions with G-actin and G-actin-DNase complexes respectively. However, reduction of pH caused a progressive decrease in binding with virtual abolition at pH less than or equal to 5.0. The latter might promote dissociation of D3 metabolites from Gc carrier protein in acidic compartments of cells.
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Affiliation(s)
- B Boutin
- Department of Microbiology, Medical University of South Carolina, Charleston 29425
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39
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Van Baelen H, Allewaert K, Bouillon R. New aspects of the plasma carrier protein for 25-hydroxycholecalciferol in vertebrates. Ann N Y Acad Sci 1988; 538:60-8. [PMID: 3056194 DOI: 10.1111/j.1749-6632.1988.tb48850.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- H Van Baelen
- Laboratory for Experimental Medicine and Endocrinology, Onderwijs en Navorsing, Campus Gasthuisberg, Leuven, Belgium
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40
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Taylor GA, Mazhindu HN, Findlay JB, Peacock M. Purification of vitamin D binding protein from human plasma using high performance liquid chromatography. Clin Chim Acta 1986; 155:31-41. [PMID: 3084135 DOI: 10.1016/0009-8981(86)90096-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Vitamin D binding protein/group-specific component was purified from human plasma by chromatographic techniques utilising high performance liquid chromatography and by traditional low pressure chromatographic techniques alone. Use of high performance liquid chromatography considerably reduced the time taken to prepare pure vitamin D binding protein and increased the yield to 16% compared with 2.8% using the traditional methods. The vitamin D binding protein prepared by high performance liquid chromatography was shown to be highly pure by amino acid sequence, SDS gel electrophoresis and by antibody production. The amino acid sequence was confirmed and extended. The affinity constants of the high pressure liquid chromatography purified vitamin D binding protein for 25 hydroxycholecalciferol (25 OHD3) and 1,25 dihydroxycholecalciferol 1,25(OH)2D3 were 1.9 X 10(7) mol/l and 2.6 X 10(6) mol/l, respectively.
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Woloszczuk W. Determination of vitamin D binding protein by Scatchard analysis and estimation of a free 25-hydroxy-vitamin D index. Clin Chim Acta 1985; 145:27-35. [PMID: 3919968 DOI: 10.1016/0009-8981(85)90016-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A simple method for the quantification of the vitamin D binding capacity (concentration of vitamin D binding protein, DBP) in serum is described. 25-Hydroxy-vitamin D can conveniently be measured by a binding protein assay utilizing dilute human serum as a source of DBP. The same methodology was used to determine the concentration of DBP by Scatchard analysis. In comparison to radial immunodiffusion, a correlation coefficient of 0.863 (p less than 0.001) was found with a regression line y = 0.963x + 0.08 (n = 52). Normal values were between 3 and 8 mumol/l, the coefficient of variation was less than 7% (median 4.9%). A simple routine version of this test requiring only 5 tubes per sample at a sample dilution of 1:15 000 had an interassay variation of less than 8%. The apparent affinity constants of DBP obtained by the Scatchard analysis had a very poor interassay reproducibility. Thus, the molar ratio of 25-hydroxy-vitamin D and DBP was used as a 'free 25-hydroxy-vitamin D index'. The normal range for a control group was 0.005-0.015, with samples taken in winter.
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Abstract
In this review, the association between biologically active compounds and proteins is seen in the light of axioms expressed by Paracelsus and Paul Ehrlich long ago, and the physiological significance of the interactions is pointed out. Of the various types of proteins that form noncovalent complexes with steroid hormones, only the serum proteins will be discussed. Recent results, obtained in several laboratories, on the physicochemical properties of the human corticosteroid-binding globulin (CBG, transcortin) makes this glycoprotein perhaps the best known one among the steroid-binding serum proteins. Influence of pH on stability of the complexes, kinetics of the associations and their significance, as well as thermodynamic parameters of complex formation are being discussed. Characteristics of the binding sites are deduced from specificity studies. Influence of the entrance of hydrophilic or hydrophobic substituents into the steroid molecule illuminates the difference between typically hydrophobic binders such as the progesterone-binding globulin (PBG) of the pregnant guinea-pig and typically hydrophilic binders such as CBG. Complete elucidation of the steroid-binding proteins awaits the determination of the amino acid sequence and the X-ray crystallographic analysis of the steroid-protein complex.
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Haddad JG, Aden DP, Kowalski MA. Characterization of the human plasma binding protein for vitamin D and its metabolites synthesized by the human hepatoma-derived cell line, Hep 3B. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32300-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Marx SJ, Liberman UA, Eil C. Calciferols: actions and deficiencies in action. VITAMINS AND HORMONES 1983; 40:235-308. [PMID: 6369768 DOI: 10.1016/s0083-6729(08)60436-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Imawari M, Kozawa K, Yoshida T, Osuga T. A simple and sensitive assay for 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D and 1,25-dihydroxyvitamin D in human serum. Clin Chim Acta 1982; 124:63-73. [PMID: 6982126 DOI: 10.1016/0009-8981(82)90320-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
An improved method is described which permits the simultaneous determination of 25-hydroxyvitamin D [25-(OH)D], 24,25-dihydroxyvitamin D [24,25-(OH)2D] and 1,25-dihydroxyvitamin D [1,25-(OH)2D] in milliliters of human serum. Methodological improvements enabled a rapid and almost complete extraction of the three metabolites from serum and omission of adding labeled internal standards to each serum sample for the calculation of individual recoveries. Commercially available stable chick embryo intestinal mucosa cytosol preparation made the troublesome preparation of cytosol receptor for 1,25-(OH)2D unnecessary. The procedure involves saturation of serum with ammonium carbonate and extraction with methanol/ethyl acetate, followed by separation of 25-(OH) D from the dihydroxy metabolites of vitamin D by Sephadex LH-20 column chromatography and further separation of the dihydroxy metabolites into 24,25-(OH)2D and 1,25-(OH)2D by high-pressure liquid chromatography. This is followed by individual determination of each metabolite by competitive protein-binding assay or radioreceptor assay.
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Vial HJ, Thuet MJ, Philippot JR. Inhibition of the in vitro growth of Plasmodium falciparum by D vitamins and vitamin D-3 derivatives. Mol Biochem Parasitol 1982; 5:189-98. [PMID: 6283344 DOI: 10.1016/0166-6851(82)90020-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
D vitamins are effective inhibitors of the in vitro intraerythrocytic growth of Plasmodium falciparum. Disappearance of the parasitemia was observed after 48 h contact between infected cells and 5 x 10(-6) M 1 alpha-hydroxycholecalciferol, 5 x 10(-5) M 25-hydroxycholecalciferol (25-OH-D-3), 1 alpha, 25-dihydroxycholecalciferol or 2.5 x 10(-4) vitamin D-2 and D-3. A 48 h pretreatment of healthy erythrocytes with 5 x 10(-5) M 25-OH-D-3 did not change their susceptibility to invasion by the parasite and their ability to support the growth of P. falciparum. Ionomycin, a calcium ionophore, and EGTA prevented parasite development at concentrations greater than 2 x 10(-7) M and 4 x 10(-4) M, respectively, but did not antagonize the inhibitory activity of 25-OH-D-3. Addition of 25-OH-D-3 for 12 or 24 h duration to synchronized cultures, showed that the drug had a schizonticidal action, but was without effect when parasites were in the ring form.
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Haddad JG. Human serum binding protein for vitamin D and its metabolites (DBP): evidence that actin is the DBP binding component in human skeletal muscle. Arch Biochem Biophys 1982; 213:538-44. [PMID: 6176188 DOI: 10.1016/0003-9861(82)90581-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Dueland S, Pedersen J, Helgerud P, Drevon C. Transport of vitamin D3 from rat intestine. Evidence for transfer of vitamin D3 from chylomicrons to alpha-globulins. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)68338-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Kawakami M, Goodman DS. Effects of protein modification procedures on the interaction between 25-hydroxyvitamin D and the human plasma binding protein for vitamin D and its metabolites. Biochemistry 1981; 20:5881-7. [PMID: 6794617 DOI: 10.1021/bi00523a035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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