1
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Fu L, Wong BYL, Li Z, Horst RL, Williams R, Lee B, Miller J, Carpenter TO, Cole DEC. Genetic variants in the vitamin D pathway and their association with vitamin D metabolite levels: Detailed studies of an inner-city pediatric population suggest a modest but significant effect in early childhood. J Steroid Biochem Mol Biol 2023; 233:106369. [PMID: 37490983 DOI: 10.1016/j.jsbmb.2023.106369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 07/17/2023] [Accepted: 07/22/2023] [Indexed: 07/27/2023]
Abstract
OBJECTIVES In a large cohort of healthy infants and toddlers 6-36 months of age (n = 776), we have been exploring the potential role of genetic variation in predisposition to vitamin D insufficiency. The genes encoding the key cytochrome P450 hydroxylases (CYP2R1, CYP24A1, and CYP27B1) harbour recurrent mutations of uncertain effect. This study was undertaken to look for biochemically relevant associations of these variants with inter-individual differences in vitamin D metabolism in an at-risk pediatric population. METHODS Genotyping for CYP2R1-CT (c.-1127 C>T, rs10741657), CYP24A1-AG (c.-686A>G, rs111622401), and CYP27B1-CA (c.-1261 C>A, rs10877012) mutations were performed using SNaPshot assay, followed by Sanger sequencing confirmation. Vitamin D metabolites and vitamin D binding protein (DBP) were measured by established methods. RESULTS In a multivariate regression model, with corrections for co-variates, subjects with the homozygous CYP2R1-TT variant had significantly higher concentrations of 25(OH)D, free 25(OH)D, and 24,25(OH)2D levels. In subjects with the CYP24A1-AG mutation, concentrations of 25(OH)D were significantly higher. CONCLUSIONS The CYP2R1-TT and CYP24A1-AG variants have measurable effects on the vitamin D pathway. It seems unlikely that they will be clinically relevant in isolation, but they may be members of the large pool of infrequent mutations contributing to different risks for the vitamin D deficiency phenotype.
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Affiliation(s)
- Lei Fu
- Department of Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Sunnybrook Research Institute, Toronto, ON, Canada; Departments of Laboratory Medicine and Pathobiology, Toronto, ON, Canada
| | - Betty Y L Wong
- Department of Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Zhenyu Li
- Departments of Laboratory Medicine and Pathobiology, Toronto, ON, Canada
| | | | - Rashida Williams
- Departments of Laboratory Medicine and Pathobiology, Toronto, ON, Canada
| | - Bonnie Lee
- Departments of Laboratory Medicine and Pathobiology, Toronto, ON, Canada
| | - Jessica Miller
- Departments of Laboratory Medicine and Pathobiology, Toronto, ON, Canada
| | - Thomas O Carpenter
- Departments of Pediatrics (Endocrinology), Yale University School of Medicine, New Haven, CT, USA; Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT, USA.
| | - David E C Cole
- Pediatrics (Genetics), Toronto, ON, Canada; Medicine, University of Toronto, Toronto, ON, Canada.
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2
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Novel Approach for the Approximation of Vitamin D3 Pharmacokinetics from In Vivo Absorption Studies. Pharmaceutics 2023; 15:pharmaceutics15030783. [PMID: 36986644 PMCID: PMC10052077 DOI: 10.3390/pharmaceutics15030783] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/16/2023] [Accepted: 02/25/2023] [Indexed: 03/02/2023] Open
Abstract
The changing environment and modified lifestyles have meant that many vitamins and minerals are deficient in a significant portion of the human population. Therefore, supplementation is a viable nutritional approach, which helps to maintain health and well-being. The supplementation efficiency of a highly hydrophobic compound such as cholecalciferol (logP > 7) depends predominantly on the formulation. To overcome difficulties associated with the evaluation of pharmacokinetics of cholecalciferol, a method based on the short time absorption data in the clinical study and physiologically based mathematical modeling is proposed. The method was used to compare pharmacokinetics of liposomal and oily formulations of vitamin D3. The liposomal formulation was more effective in elevating calcidiol concentration in serum. The determined AUC value for liposomal vitamin D3 formulation was four times bigger than that for the oily formulation.
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3
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Zhu A, Kuznia S, Niedermaier T, Holleczek B, Schöttker B, Brenner H. Consistent Inverse Associations of Total, “Bioavailable”, Free, and “Non-Bioavailable” Vitamin D with Incidence of Diabetes among Older Adults with Lower Baseline HbA1c (≤6%) Levels. Nutrients 2022; 14:nu14163282. [PMID: 36014788 PMCID: PMC9413175 DOI: 10.3390/nu14163282] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/04/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Serum 25-hydroxyvitamin (25(OH)D) levels are inversely associated with risk of diabetes. The “free hormone hypothesis” suggests potential effects to be mainly related to concentrations of “bioavailable” and free rather than total 25(OH)D. We assessed associations of serum concentrations of vitamin D-binding protein (VDBP), as well as total “bioavailable”, complementary “non-bioavailable”, and free 25(OH)D, with the risk of developing diabetes among non-diabetic older adults in a large population-based cohort study in Germany. Methods: We included 4841 non-diabetic older adults aged 50–75 years at the baseline exam from the ESTHER cohort conducted in Saarland, Germany, in 2001–2002. Concentrations of “bioavailable” and free 25(OH)D were derived from serum concentrations of VDBP, total 25(OH)D, and albumin. Incidence of diabetes was ascertained during up to 14 years of follow-up. Associations were quantified by multivariable Cox proportional hazards regression models with comprehensive confounder adjustment. Results: During a median follow-up of 10.6 years, 837 non-diabetic participants developed diabetes. We observed similar inverse associations with developing diabetes for VDBP (hazard ratio (HR) for lowest versus highest quintile: 1.37, 95% confidence interval (CI): 1.09, 1.72), total 25(OH)D (HR: 1.31, 95% CI: 1.03, 1.66), and “non-bioavailable” 25(OH)D (HR: 1.30, 95% CI: 1.02, 1.65). Associations were smaller and statistically insignificant for “bioavailable” and free 25(OH)D. However, associations of total “non-bioavailable”, “bioavailable”, and free 25(OH)D with incidence of diabetes were much stronger among, and essentially restricted to, participants with lower baseline HbA1c (≤6%) levels. Conclusions: This large prospective cohort study of older Caucasian adults, in agreement with results from randomized trials and Mendelian randomization studies, supports a protective effect of vitamin D against development of diabetes. The “free hormone theory” may not be relevant in this context. However, our results underline the importance of adequate vitamin D status among those who have not yet shown any sign of impaired glucose tolerance.
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Affiliation(s)
- Anna Zhu
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Medical Faculty Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Sabine Kuznia
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Medical Faculty Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Tobias Niedermaier
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | | | - Ben Schöttker
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Network Aging Research, Heidelberg University, 69115 Heidelberg, Germany
| | - Hermann Brenner
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Network Aging Research, Heidelberg University, 69115 Heidelberg, Germany
- Division of Preventive Oncology, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Correspondence: ; Tel.: +49-6221421300
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Maghbooli Z, Ebrahimi Meimand S, Malek Hosseini AA, Shirvani A. Alterations in circulating levels of vitamin D binding protein, total and bioavailability of vitamin D in diabetic retinopathy patients. BMC Endocr Disord 2022; 22:169. [PMID: 35778716 PMCID: PMC9250226 DOI: 10.1186/s12902-022-01084-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 06/22/2022] [Indexed: 12/04/2022] Open
Abstract
AIMS This study aimed to investigate the association between circulating levels of vitamin D binding protein (VDBP) and its genotypes and diabetic retinopathy risk. METHODS This case-control study recruited 154 patients with type 2 diabetes mellitus; 62 with diabetic retinopathy (DR) and 92 without DR and diabetic nephropathy (DN). Circulating levels of 25-hydroxyvitamin D3 and VDBP levels were measured in the patients. The genotype and phenotype of VDBP were evaluated based on two common VDBP variations; rs7041 and rs4588. RESULTS Serum levels of VDBP were significantly lower in patients with DR than in patients without DR and/or DN (Ln-VDBP (μg/ml): 6.14 ± 0.92 vs. 6.73 ± 1.45, p = 0.001) even after adjustment for age, sex, body mass index, disease duration, estimated glomerular filtration rate (eGFR), HbA1C, insulin therapy profile, and serum levels of 25(OH)D. The distribution of VDBP phenotypes and genotypes in the two studied groups were nearly the same, and the distribution was similar to that of the general population. CONCLUSIONS In this study, we found the association between lower circulating levels of VDBP and risk of DR. However, the precise mechanism linking these two remains unknown. Further and more in-depth research is needed to find out the underlying causes of the relationship.
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Affiliation(s)
- Zhila Maghbooli
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran.
| | | | - Ali-Asghar Malek Hosseini
- Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran
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Zeng S, Chu C, Doebis C, von Baehr V, Hocher B. Reference values for free 25-hydroxy-vitamin D based on established total 25-hydroxy-vitamin D reference values. J Steroid Biochem Mol Biol 2021; 210:105877. [PMID: 33741448 DOI: 10.1016/j.jsbmb.2021.105877] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 03/10/2021] [Accepted: 03/13/2021] [Indexed: 12/15/2022]
Abstract
Measurements of total 25-hydroxyvitamin D (t25(OH)D) are currently primarily used to assess the vitamin D status. The lipophilic cell membrane can only be passed by the un-bound form of 25-hydroxyvitamin D: free 25-hydroxyvitamin D (f25(OH)D). It is thought that f25(OH)D does reflect its biological actions better than t25(OH)D. However, as of today, there are no established guidelines for the clinical use of f25(OH)D. We analysed 5060 patients with simultaneous measurements of free and total 25(OH). Linear regression was used to study the relationship between free 25(OH)D and total 25(OH)D. We reviewed and used the established t25(OH)D reference values and determined the slope of the relationship between them to calculate reference values for f25(OH)D. F25(OH)D and t25(OH)D showed a strong positive linear (r = 0.8395, p < 0.0001) correlation. The slope of the relationship was 0.2833 ± 0.00257. The recommended threshold level of f25(OH)D is 8.499 pg/mL, corresponding to a target concentration for t25(OH)D of at least 30 ng/mL considered as sufficient in most of the international vitamin D guidelines. The upper limit for vitamin D is less clear in the guidelines. Most experts favour an upper limit for t25(OH)D of 100 ng/mL. This is equivalent to 28.330 pg/mL f25OHD. We established based on international guidelines for t25(OH)D reference values for f25(OH)D that are urgently needed for clinical use of f25(OH)D. However, clinical studies with f25(OH)D to confirm our suggestions are needed but will take time.
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Affiliation(s)
- Shufei Zeng
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology), University Medical Centre Mannheim, University of Heidelberg, Germany; Department of Nephrology, Charité - Universitätsmedizin Berlin, Campus Mitte, Berlin, Germany; Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Chang Chu
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology), University Medical Centre Mannheim, University of Heidelberg, Germany; Department of Nephrology, Charité - Universitätsmedizin Berlin, Campus Mitte, Berlin, Germany
| | - Cornelia Doebis
- Institute of Medical Diagnostics, IMD Berlin-Potsdam, Berlin, Germany
| | - Volker von Baehr
- Institute of Medical Diagnostics, IMD Berlin-Potsdam, Berlin, Germany
| | - Berthold Hocher
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology), University Medical Centre Mannheim, University of Heidelberg, Germany; Institute of Medical Diagnostics, IMD Berlin-Potsdam, Berlin, Germany; Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China; Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.
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6
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Bone regeneration in a mouse model of type 1 diabetes: Influence of sex, vitamin D3, and insulin. Life Sci 2020; 263:118593. [PMID: 33069738 DOI: 10.1016/j.lfs.2020.118593] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/01/2020] [Accepted: 10/07/2020] [Indexed: 02/06/2023]
Abstract
AIM This study set forth a question: are there any differences in bone responses to insulin and/or vitamin D3 treatment in female and male type 1 diabetic (T1D) mice? MAIN METHODS To address this issue, a non-critical sized femur defect was created in streptozotocin (STZ)-T1D mice. Control non-diabetic and T1D female and male mice received: saline; vitamin D3; insulin; or vitamin D3 plus insulin, for 21 days. KEY FINDINGS Female and male T1D mice showed impaired bone healing, as indicated by histological and micro-computed tomography (micro-CT) analysis. Vitamin D3 or insulin improved the bone regeneration in T1D mice, irrespective of sex. Vitamin D3 plus insulin did not exhibit any additional effects. There were no differences regarding the numbers of TRAP-stained osteoclasts in either evaluated groups. The osteoblast-related gene osterix was upregulated in vitamin D3-treated male T1D mice, as revealed by RT-qPCR. Female T1D mice treated with vitamin D3, insulin, or vitamin D3 plus insulin presented an increased expression of insulin growth factor-1 (IGF-1) mRNA. Conversely, IGF-1 mRNA levels were reduced by the same treatments in male TD1 mice. SIGNIFICANCE Altogether, the results suggested that T1D similarly delayed the osseous healing in female and male mice, with beneficial effects for either vitamin D3 or insulin in T1D mice of both sexes. However, data indicated marked sex differences regarding the expression of genes implicated in bone formation, in T1D mice treated with vitamin D3 and/or insulin.
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7
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Tenesaca S, Vasquez M, Fernandez-Sendin M, Di Trani CA, Ardaiz N, Gomar C, Cuculescu D, Alvarez M, Otano I, Melero I, Berraondo P. Scavenger Receptor Class B Type I is Required for 25-Hydroxycholecalciferol Cellular Uptake and Signaling in Myeloid Cells. Mol Nutr Food Res 2020; 64:e1901213. [PMID: 32583974 DOI: 10.1002/mnfr.201901213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 06/01/2020] [Indexed: 11/12/2022]
Abstract
SCOPE Vitamin D3 is a critical molecule for the properly controlled activity of the immune system. In myeloid-derived cells, vitamin D3 induces the production of the antimicrobial and antitumor peptide cathelicidin. In this study, the mechanism of the entry of 25-hydroxycholecalciferol (25(OH)D) in myeloid-derived cells is explored. METHODS AND RESULTS Here, a novel regulatory pathway of vitamin D3 biology is described. Using a polyclonal antibody, two different chemical inhibitors, and a high-density lipoprotein as a competing ligand, it is demonstrated here that the 25(OH)D signaling pathway in myeloid cells depends on scavenger receptor class B type I (SR-B1). This effect is observed in the THP-1 monocytic cell line and in human primary monocytes. SR-B1 blockade abrogates the cellular uptake of 25(OH)D leading to a general shut down of the gene transcription program modulated by 25(OH)D. The results obtained at the transcriptional level are confirmed at the protein and functional level for CD14 in the THP-1 cell line. CONCLUSION In conclusion, SR-B1 plays a critical role in vitamin D3 biology, paving the way for novel therapeutic interventions.
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Affiliation(s)
- Shirley Tenesaca
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain
| | - Marcos Vasquez
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain
| | - Myriam Fernandez-Sendin
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain
| | - Claudia Augusta Di Trani
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain
| | - Nuria Ardaiz
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain
| | - Celia Gomar
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain
| | - Doina Cuculescu
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain
| | - Maite Alvarez
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain
| | - Itziar Otano
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain
| | - Ignacio Melero
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain.,Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, 31008, Spain.,Department of Oncology, Clínica Universidad de Navarra, Pamplona, 31008, Spain
| | - Pedro Berraondo
- Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, 31008, Spain.,Navarra Institute for Health Research (IDISNA), Pamplona, 31008, Spain.,Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, 31008, Spain
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8
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Temporal Dynamics of High-Density Lipoprotein Proteome in Diet-Controlled Subjects with Type 2 Diabetes. Biomolecules 2020; 10:biom10040520. [PMID: 32235466 PMCID: PMC7226298 DOI: 10.3390/biom10040520] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/18/2020] [Accepted: 03/28/2020] [Indexed: 12/15/2022] Open
Abstract
We examined the effect of mild hyperglycemia on high-density lipoprotein (HDL) metabolism and kinetics in diet-controlled subjects with type 2 diabetes (T2D). 2H2O-labeling coupled with mass spectrometry was applied to quantify HDL cholesterol turnover and HDL proteome dynamics in subjects with T2D (n = 9) and age- and BMI-matched healthy controls (n = 8). The activities of lecithin–cholesterol acyltransferase (LCAT), cholesterol ester transfer protein (CETP), and the proinflammatory index of HDL were quantified. Plasma adiponectin levels were reduced in subjects with T2D, which was directly associated with suppressed ABCA1-dependent cholesterol efflux capacity of HDL. The fractional catabolic rates of HDL cholesterol, apolipoprotein A-II (ApoA-II), ApoJ, ApoA-IV, transthyretin, complement C3, and vitamin D-binding protein (all p < 0.05) were increased in subjects with T2D. Despite increased HDL flux of acute-phase HDL proteins, there was no change in the proinflammatory index of HDL. Although LCAT and CETP activities were not affected in subjects with T2D, LCAT was inversely associated with blood glucose and CETP was inversely associated with plasma adiponectin. The degradation rates of ApoA-II and ApoA-IV were correlated with hemoglobin A1c. In conclusion, there were in vivo impairments in HDL proteome dynamics and HDL metabolism in diet-controlled patients with T2D.
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9
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Pelczyńska M, Grzelak T, Sperling M, Kręgielska-Narożna M, Bogdański P, Czyżewska K. Evaluation of Vitamin D Fractions in Obese Hypertensive Patients. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17051660. [PMID: 32143350 PMCID: PMC7084800 DOI: 10.3390/ijerph17051660] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/01/2020] [Accepted: 03/02/2020] [Indexed: 12/16/2022]
Abstract
Vitamin D fractions can be involved in the pathogenesis of metabolic disorders, but their concentrations are rarely determined. The aim of this study was to evaluate the concentration of vitamin D fractions in obese hypertensive patients and to determine its associations with anthropometric parameters, glucose levels, and lipid profiles. A total of 85 obese hypertensive patients (OBHT) and 40 nonobese nonhypertensive subjects (NOBNHT) underwent biochemical measurements of lipid profiles, glycemia, 25-hydroxyvitamin D (25(OH)D), free vitamin D (free25(OH)D), vitamin D binding protein, albumin levels. Moreover, free25(OH)D and bioavailable25(OH)D (bio25(OH)D) concentrations were calculated. Blood pressure and anthropometric measurements were performed. Differences between groups (p < 0.001) were found for 25(OH)D (OBHT 40.25 ± 18.02 vs. NOBNHT 64.10 ± 22.29 nmol/L), free25(OH)D (9.77 (7.46; 11.49) vs. 13.80 (10.34; 16.82) pmol/L), bioavailable 25(OH)D (3.7 (2.8; 4.4) vs. 5.4 (4.2; 6.7) nmol/L), and calculated free25(OH)D (7.82 (5.54; 11.64) vs. 10.46(8.06;16.28) pmol/L, p = 0.002). The OBHT patients showed no relationship between vitamin D fractions concentration and glucose or lipids level, although it was associated with anthropometric parameters. In the NOBNHT group, vitamin D fractions correlated positively with HDL cholesterol and negatively with triglyceridemia and hip circumference. Vitamin D fractions were decreased in obese hypertensive subjects, and were associated with anthropometric parameters, but not with glucose level or lipid profiles; they thus cannot be considered as a predictive marker of metabolic disorders in this group of patients.
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Affiliation(s)
- Marta Pelczyńska
- Department of Treatment of Obesity, Metabolic Disorders and Clinical Dietetics, Poznan University of Medical Sciences, Szamarzewskiego 84 St., 60-569 Poznan, Poland
- Correspondence:
| | - Teresa Grzelak
- Department and Division of Physiology, Poznan University of Medical Sciences, Swiecickiego 6 St., 60-781 Poznan, Poland
| | - Marcelina Sperling
- Division of Biology of Civilization-Linked Diseases, Poznan University of Medical Sciences, Swiecickiego 6 St., 60-781 Poznan, Poland
| | - Matylda Kręgielska-Narożna
- Department of Treatment of Obesity, Metabolic Disorders and Clinical Dietetics, Poznan University of Medical Sciences, Szamarzewskiego 84 St., 60-569 Poznan, Poland
| | - Paweł Bogdański
- Department of Treatment of Obesity, Metabolic Disorders and Clinical Dietetics, Poznan University of Medical Sciences, Szamarzewskiego 84 St., 60-569 Poznan, Poland
| | - Krystyna Czyżewska
- Stanisław Staszic University of Applied Sciences in Pila, Podchorazych 10 St., 64-920 Pila, Poland
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Lisowska-Myjak B, Jóźwiak-Kisielewska A, Łukaszkiewicz J, Skarżyńska E. Vitamin D-binding protein as a biomarker to confirm specific clinical diagnoses. Expert Rev Mol Diagn 2019; 20:49-56. [PMID: 31795772 DOI: 10.1080/14737159.2020.1699064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction: Vitamin D-binding protein (DBP) performs a variety of functions as a transporter for various ligands and takes part in a number of systemic and local physiological and pathological processes. The knowledge about the pathomechanisms of this protein involvement justifies its use as a biomarker to confirm specific clinical diagnoses suggested by nonspecific signs and symptoms.Areas covered: DBP has properties of both systemic laboratory parameters measured in the blood plasma and specific parameters measured in variety of physiological fluids to assess local changes in specific body organs. Articles published in English between 1993 and 2019 were searched for in PubMed using terms DBP, vitamin D, and metabolites, inflammation. DBP is a transport protein and a regulator of immune and inflammatory processes.Expert opinion: DBP capacity for transporting numerous ligands and co-involvement of DBP in immune and inflammatory processes suggest that DBP may be used in laboratory diagnostics as a specific parameter to confirm pathomechanisms of several systemic diseases and local conditions. Changes in the concentration of DBP present in a variety of clinical material may provide valuable information for use in assessing the severity and treatment of pathological processes.
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Affiliation(s)
- Barbara Lisowska-Myjak
- Department of Biochemistry and Clinical Chemistry, Medical University of Warsaw, Warsaw, Poland
| | | | - Jacek Łukaszkiewicz
- Department of Biochemistry and Clinical Chemistry, Medical University of Warsaw, Warsaw, Poland
| | - Ewa Skarżyńska
- Department of Biochemistry and Clinical Chemistry, Medical University of Warsaw, Warsaw, Poland
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11
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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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