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Effect of combined vitamin D receptor activator and lanthanum carbonate on serum fibroblast growth factor 23 level in predialysis patients (CVD-LAF study): design and method.
Ito, E, Inaguma, D, Koide, S, Takahashi, K, Hayashi, H, Hasegawa, M, Yuzawa, Y
Clinical and experimental nephrology. 2018;(6):1309-1314
Abstract
BACKGROUND Whether vitamin D receptor activator (VDRA) use is beneficial in chronic kidney disease (CKD) is unclear, because it is possible that VDRA increases serum fibroblast growth factor 23 (FGF23) levels. We will conduct a randomized controlled trial in predialysis patients to determine the effect of VDRA alone or in combination with lanthanum carbonate (LC) on serum FGF23 levels. METHODS This is a single-center, open-label, randomized controlled trial. Enrollment will commence February 1, 2018, using the following inclusion criteria: (1) age ≥ 20 years, (2) CKD with an estimated glomerular filtration rate of 10-45 mL/min/1.73 m2, (3) serum adjusted calcium level < 9.5 mg/dL, (4) serum phosphate level 4.0-6.0 mg/dL, and (5) serum intact parathyroid hormone (PTH) level ≥ 60 pg/mL. Study patients will be randomized 1:1 to receive alfacalcidol alone or in combination with LC. The initial dose of alfacalcidol will be 0.25-0.5 µg once a day according to serum adjusted calcium level. The initial dose of LC will be 250 mg once a day. We will measure serum intact and C-terminal FGF23 at 0, 4, 8, 12, 24, and 52 weeks. The primary outcome will be serum FGF23 level at 24 weeks compared with baseline. DISCUSSION This study aims to determine whether low-dose oral VDRA increases serum FGF23 level and whether the combination of VDRA and LC inhibits this increase. The results will be useful in the management of CKD-mineral and bone disorder in predialysis patients. TRIAL REGISTRATION UMIN000030503. Registered 20 January 2018.
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Effects of human interleukins in the transgenic gene reporter cell lines IZ-VDRE and IZ-CYP24 designed to assess the transcriptional activity of vitamin D receptor.
Bartonkova, I, Kallay, E, Dvorak, Z
PloS one. 2018;(2):e0193655
Abstract
The role of vitamin D receptor (VDR) in immune responses has been broadly studied and it has been shown that activated VDR alters the levels of some interleukins (ILs). In this study, we studied the opposite, i.e. whether 13 selected pro-inflammatory and anti-inflammatory ILs influence the transcriptional activity of human VDR. The experimental models of choice were two human stably transfected gene reporter cell lines IZ-VDRE and IZ-CYP24, which were designed to evaluate the transcriptional activity of VDR. The gene reporter assays revealed inhibition of calcitriol-induced luciferase activity by IL-4 and IL-13, when 1 ng/mL of these two compounds decreased the effect of calcitriol down to 60% of the control value. Consistently, calcitriol-induced expression of CYP24A1 mRNA was also significantly decreased by IL-4 and IL-13. The expression of VDR and CYP27B1 mRNAs was not influenced by any of the 13 tested ILs. These data suggest possible cross-talk between the VDR signalling pathway and IL-4- and IL-13-mediated cell signalling.
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Association between VDR polymorphisms and multiple sclerosis: systematic review and updated meta-analysis of case-control studies.
Zhang, YJ, Zhang, L, Chen, SY, Yang, GJ, Huang, XL, Duan, Y, Yang, LJ, Ye, DQ, Wang, J
Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology. 2018;(2):225-234
Abstract
Vitamin D receptor (VDR) polymorphisms have been inconsistently investigated in multiple sclerosis (MS). However, published studies demonstrated differences concerning design and effect size. A meta-analysis is necessary to determine the magnitude of the association between VDR polymorphisms and MS risk. The aim of the current study was to quantify the magnitude of the association between BsmI, FokI, ApaI, and TaqI VDR polymorphisms and MS risk. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a systematic search and meta-analysis of the VDR gene polymorphisms and the risk of MS. The pooled odds ratios (OR) and 95% confidence interval (CI) were calculated by using Stata Version 11.0 with dominant and recessive models and allele analyses. A total of 4013 cases and 4218 controls in 24 case-control studies were included in the meta-analyses. The results did not indicate an association between any of the VDR polymorphisms and the risk of MS among overall populations, Asians, and Caucasians. However, our subgroup analysis suggests that the A allele was associated with MS risk in Asian populations (P = 0.005, OR = 1.267, 95% CI 1.074-1.496). Interestingly, the sensitivity analysis excluding studies with controls not in HWE showed insignificant association between the A allele and MS risk (P = 0.211), which was different from those in the non-sensitivity analysis. Our preliminary results indicate the VDR gene ApaI, BsmI, FokI, and TaqI polymorphisms may not be associated with elevated MS risk among overall populations. But ApaI polymorphism may confer different susceptibility to MS among different populations, and more well-designed studies with a large sample size are still needed to validate our results.
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Impact of vitamin D receptor and binding protein gene polymorphisms in clinical and laboratory data of HCV patients: Cross sectional study.
Scalioni, LP, Santos, BRD, Spritzer, PM, Villela-Nogueira, CA, Laura Lewis-Ximenez, L, Pollo-Flores, P, Bordalo Cathalá Esberard, E, Brandão-Mello, CE, Lampe, E, Villar, LM
Medicine. 2018;(8):e9881
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Abstract
Potential relationship of vitamin D, vitamin D receptor (VDR), and vitamin D binding protein (DBP) have been suggested in the pathophysiology of hepatitis C virus (HCV) infection. The aim of this observational study is to determine vitamin D levels, and VDR and DBP genetic polymorphism according demographic and laboratory data in chronic HCV patients (CHC).A total of 148 CHC patients gave serum samples for testing 25-hydroxyvitamin D (25 (OH)D) level by immunochemiluminometric assay (<20 ng/mL defined as deficient) and donated blood samples to allelic discrimination analysis using TaqMan assays. Analyzed single nucleotide polymorphisms (SNPs) were: VDR-rs7975232 (ApaI) C>A, rs731236 A>G (TaqI), rs1544410 C>T (BsmI), rs10735810 T>C (FokI) and carrier globulin/binding protein (GC)-rs4588 and rs7041 and the haplotype bAt [CCA]. Hepatic fibrosis was assessed using Fib-4 and Forns index.Eighty-two (54.40%) patients demonstrated deficiency of vitamin D and this was associated to AST (P = .019 [CI: 1.003-1.034]), total cholesterol (P = .038 [CI: 1.004-1.164]), fibrosis grade (P < .001 [CI: 0.000-0.844]), and FokI (P = .028) allele T presence. Association was found between VDR polymorphism and fibrosis (BsmI andTaqI), triglycerides (TaqI), and HDL (FokI). DBP polymorphism was associated to HCV genotype (GC rs7041), previous HCV treatment, and GGT (GC rs4588).In conclusion, low frequency of vitamin D deficiency was found, but VDR polymorphisms were frequently associated to fibrosis grade suggesting that they could be used as disease evaluation markers to understand the mechanisms underlying the virus-host interaction.
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Associations of Vitamin D Levels and Vitamin D Receptor Genotypes with Patient-Reported Outcome/Disease Activity in Patients with Rheumatoid Arthritis.
Khoja, SO, El-Miedany, Y, Iyer, AP, Bahlas, SM, Balamash, KS, Elshal, MF
Clinical laboratory. 2018;(1):51-58
Abstract
BACKGROUND The aim of this study is to evaluate the prevalence of vitamin-D insufficiency and vitamin-D receptor (VDR) polymorphisms in rheumatoid arthritis (RA) patients and its association with disease activity and patient reported outcomes (PROs). METHODS Eighty-two individuals were included in a cross-sectional study (41 RA patients, 41 controls). Prior to assessment, each patient completed a PRO questionnaire. Serum vitamin-D levels and genotyping for VDR were assessed. Vitamin-D deficient patients received vitamin-D supplementation. Re-assessment of disease activity (DAS28) was performed after 9-months. RESULTS Low vitamin-D levels were more frequent in RA patients (p < 0.01). A negative, but insignificant, association with DAS-28 score was identified; whereas, there was a significant negative association with the PROs (p < 0.01). Vitamin-D supplementation was associated with significant improvement in the patients' scores for pain, fatigue, global assessment, physical disability, and quality of life. In contrast to the control group, the frequency of the recessive TaqI and FokI genotypes was higher in RA patients. CONCLUSIONS In RA patients, serum vitamin-D level was significantly and inversely associated with both PROs and disease activity. The TaqI and FokI fragment length polymorphisms of VDR significantly contributed to the risk of RA. Having a significant positive impact on patient reported outcomes, vitamin-D supplementation may have a role in RA management.
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Mutation goals in the vitamin D receptor predicted by computational methods.
Sicinska, W, Gront, D, Sicinski, K
The Journal of steroid biochemistry and molecular biology. 2018;:210-220
Abstract
The mechanism through which nuclear receptors respond differentially to structurally distinct agonists is a poorly understood process. We present a computational method that identifies nuclear receptor amino acids that are likely involved in biological responses triggered by ligand binding. The method involves tracing how structural changes spread from the ligand binding pocket to the sites on the receptor surface, which makes it a good tool for studying allosteric effects. We employ the method to the vitamin D receptor and verify that the identified amino acids are biologically relevant using a broad range of experimental data and a genome browser. We infer that surface vitamin D receptor residues K141, R252, I260, T280, T287 and L417 are likely involved in cell differentiation and antiproliferation, whereas P122, D149, K321, E353 and Q385 are linked to carcinogenesis.
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Vitamin D receptor FokI polymorphism and the risks of colorectal cancer, inflammatory bowel disease, and colorectal adenoma.
Cho, YA, Lee, J, Oh, JH, Chang, HJ, Sohn, DK, Shin, A, Kim, J
Scientific reports. 2018;(1):12899
Abstract
Based on an inverse association between vitamin D levels and the risks of colorectal diseases, a functional start codon polymorphism in the vitamin D receptor (VDR) gene is speculated to affect the risks for these diseases. To validate this hypothesis, we first conducted a case-control study of 695 colorectal cancer patients and 1,397 controls. The association of VDR FokI polymorphism with colorectal cancer risk was analyzed using a logistic regression model. In the present case-control study, compared to the F allele, the f allele seemed to be associated with lower risks of colon cancer and advanced colorectal cancer. Additionally, a meta-analysis of 27 studies was conducted to combine findings from previous studies investigating the association of FokI polymorphism with colorectal disease using a random effects model. In the present meta-analysis, the f allele was positively associated with the risk of inflammatory bowel disease, including Crohn's disease and ulcerative colitis. However, this allele was inversely associated with colon cancer and was not associated with the risk of rectal cancer or colorectal adenoma. In conclusion, the findings from this study imply that the role of VDR FokI polymorphism may differ based on the type and severity of colorectal disease.
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Genetic Factors and Molecular Mechanisms of Vitamin D and Obesity Relationship.
Ruiz-Ojeda, FJ, Anguita-Ruiz, A, Leis, R, Aguilera, CM
Annals of nutrition & metabolism. 2018;(2):89-99
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Abstract
Vitamin D (vitD) deficiency is associated with a wide range of chronic diseases and conditions, including obesity, and with an increasing severity of metabolic dysregulation, such as insulin resistance, hyperlipidemia, liver disease, and hypertension, both in children and adults. However, the nature of the association between low vitD status and obesity remains unclear. This fact has motivated the scientific community to conduct genetic association analyses between 25-hydroxyvitamin D (25[OH]D)-related genes and obesity traits. In this line, the variation in the vitD receptor (VDR) gene represents the bulk of the findings. Specifically, polymorphisms in the VDR gene have been associated with obesity traits in some but not all, studies. Thus, results regarding this matter remain inconclusive. Other genes aside from VDR have also been investigated in relation to obesity-related traits. However, again, findings have been inconsistent. In general, results point to the fact that the DBP/GC gene could be an important protein-linking obesity and vitD status. On the other hand, several studies have attempted to determine the molecular mechanism of the relationship between 25(OH)-D levels and obesity. Some of these studies suggest that vitD, due to its fat-soluble characteristic, is retained by the adipose tissue and has the capacity to metabolize 25(OH)-D locally, and this can be altered during obesity. Additionally, vitD is capable of regulating the gene expression related to adipogenesis process, inflammation, oxidative stress, and metabolism in mature adipocytes. Therefore, the aim of the present review was to evaluate the association between obesity and vitD deficiency describing the main molecular mechanism of the relationship and the link with genetic factors. Key Messages: Low serum 25(OH)-D is positively associated with obesity or BMI in adults and children. Circulating vitD concentrations are, at least, partially determined by genetic factors. VitD plays an important role in the adipogenesis process and inflammation status in adipocytes and adipose tissue.
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Association between polymorphisms in vitamin D receptor gene and adolescent idiopathic scoliosis: a meta-analysis.
Dai, J, Lv, ZT, Huang, JM, Cheng, P, Fang, H, Chen, AM
European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2018;(9):2175-2183
Abstract
PURPOSE This meta-analysis was performed to clarify whether the two single nucleotide polymorphisms (ApaI and BsmI) in vitamin D receptor (VDR) gene conferred susceptibility to adolescent idiopathic scoliosis (AIS). METHODS A comprehensive literature search in five online databases (PubMed, EMBASE, ISI Web of Science, CNKI, and Wanfang) was performed to identify studies that analyzed the association between VDR gene polymorphisms and risk of AIS. Observational studies met the predetermined inclusion criteria were selected for meta-analysis. The most appropriate genetic model was identified using a genetic model-free approach. Meta-analysis was performed using RevMan 5.3 software. RESULTS Five eligible studies were included in this meta-analysis, which involved a total of 717 cases and 554 controls. A statistically significant association was observed between BsmI polymorphism and AIS (OR 1.90, 95% CI 1.32, 2.62). In subgroup analysis by ethnicity, the association between BsmI polymorphism and AIS was significant in Asians (OR 2.06, 95% CI 1.56, 2.73) but not in Caucasians (OR 0.70, 95% CI 0.23, 2.19). However, the ApaI polymorphism was not associated with AIS. Moreover, no evidence of association between BMD and the two VDR gene polymorphisms was detected. CONCLUSIONS Meta-analysis of existing data suggested that BsmI was associated with increased risk of AIS in Asian populations. Nevertheless, further studies with rigorous design and more ethnic groups are encouraged to validate our findings. These slides can be retrieved under Electronic Supplementary Material.
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Association of vitamin D receptor BsmI rs1544410 and ApaI rs7975232 polymorphisms with susceptibility to adolescent idiopathic scoliosis: A systematic review and meta-analysis.
Yin, X, Wang, H, Guo, J, Zhang, L, Zhang, Y, Li, L, Hou, S
Medicine. 2018;(2):e9627
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Abstract
BACKGROUND AIS is the most common spinal deformity disease, yet its etiology remains uncertain. Significant associations have been found between AIS risk and vitamin D receptor (VDR) gene polymorphisms; however, some of these results are controversial. The aim of this study was to determine whether VDR BsmI rs1544410 and ApaI rs7975232 polymorphisms are correlated with AIS. METHODS Databases, including PubMed, EMBASE, Web of Science, the Cochrane Library, the Chinese Biomedical Literature Database, and the Wanfang Database, were systematically searched, and eligible case-control studies that explored the association of VDR (BsmI and ApaI) and the susceptibility to AIS were selected. The pooled odds ratio (OR) with 95% confidence interval (95% CI) was calculated to assess the associations, and subgroup meta-analyses were performed according to the ethnicity of the study population. RESULTS A total of 5 studies with 717 cases and 554 controls fulfilled the inclusion criteria after assessment by 2 reviewers. Generally, significant correlations were found between the BsmI polymorphism and AIS risk in overall populations and in Asian populations (overall population: B vs b: OR = 2.12, 95% CI = 1.21-3.75, P = .009; BB vs bb: OR = 3.38, 95% CI = 1.08-10.57, P = .036; Bb vs bb: OR = 2.50, 95% CI = 1.29-4.82, P = .006; BB/Bb vs bb: OR = 2.71, 95% CI = 1.31-5.63, P = .007; Asian population: B vs b: OR = 2.42, 95% CI = 1.27-4.61, P = .007; BB vs bb: OR = 4.09, 95% CI = 1.03-16.22, P = .045; Bb vs bb: OR = 2.94, 95% CI = 1.42-6.10, P = .004; BB/Bb vs bb: OR = 3.23, 95% CI = 1.42-7.35, P = .005). There was no significant association observed in Caucasian populations (all P > .05). With regard to the ApaI polymorphism, we found that it significantly decreased the risk of AIS (Aa vs AA: OR = 0.43, 95% CI = 0.24-0.77, P = .004; Aa/aa vs AA: OR = 0.52, 95% CI = 0.30-0.91, P = .023); however, we could not draw a definitive conclusion for Caucasian populations, as no studies have been conducted in this group to determine the role of the VDR ApaI polymorphism in AIS etiology and development. CONCLUSION VDR BsmI was significantly associated with AIS susceptibility in the overall and Asian populations, while the VDR ApaI polymorphism only played a key role in AIS etiology and development in Asian populations.