Correlation of CYP2R1 gene promoter methylation with circulating vitamin D levels among healthy adults.

Background & objectives: Despite being a tropical country, vitamin D deficiency is highly prevalent in India with studies indicating 40-99 per cent prevalence. Apart from calcium and phosphate metabolism, vitamin D is involved in cell cycle regulation, cardiovascular, hepatoprotection. The metabolism of vitamin D is regulated by vitamin D tool genes (CYP2R1/CYP27B1/CYP24A1/VDR). The promoter regions of some of these genes have CpG islands, making them prone to methylation induced gene silencing, which may cause a reduction in circulating vitamin D levels. Epigenetic basis of vitamin D deficiency is yet to be studied in India, and hence, this pilot study was aimed to analyze whether methylation levels of CYP2R1 gene were correlated with the levels of 25(OH)D in healthy, adult individuals in Indian population. Methods: In this cross-sectional study, healthy adults of 18-45 yr of age with no history of malabsorption, thyroidectomy, chronic illness or therapeutic vitamin D supplementation were recruited. DNA methylation analysis was carried out by methylation specific quantitative PCR. Serum calcium, phosphate and vitamin D levels were also quantified. Statistical analysis was done by R 4.0.5 software. Results: A total of 61 apparently healthy adults were analyzed. The serum vitamin D levels did not correlate with CYP2R1 methylation levels in our study population. Significant positive correlation was observed between age and serum vitamin D levels. Significant association of gender was found with CYP2R1 methylation levels. Interpretation & conclusions: This study found no significant correlation between levels of CYP2R1 methylation and circulating 25(OH)D deficiency. Further studies on the Indian population having a larger sample size including entire vitamin D tool genes, among different ethnic groups may be conducted to elucidate molecular etiology of circulating 25(OH)D deficiency. The high prevalence of normal serum calcium and phosphate levels among vitamin D deficient subjects in this study coupled with the strikingly high prevalence of the deficiency at the national level, may suggest the need to revise the cut-off criteria for vitamin D deficiency in the Indian population.

Effects of bicyclol on hepatic sinusoidal obstruction syndrome induced by Gynura segetum.

BACKGROUND: The intake of Gynura segetum, a traditional Chinese medicine, may be induce hepatic sinusoidal obstruction syndrome (HSOS). It has a high mortality rate based on the severity of the disease and the absence of therapeutic effectiveness. Therefore, the current study was designed to investigate the effects of bicyclol on HSOS induced by Gynura segetum and the potential molecular mechanisms. METHODS: Gynura segetum (30 g/kg) was administered for 4 weeks in the model group, while the bicyclol pretreatment group received bicyclol (200 mg/kg) administration. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), cholesterol (CHO), triglyceride (TG), and liver histological assays were detected to assess HSOS. The gene expressions of cytochrome P450 (CYP450) isozymes were quantified by real-time PCR. Moreover, hepatocellular apoptosis was detected using the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, then apoptosis and autophagy-related markers were determined using Western blot. RESULTS: As a result, bicyclol pretreatment is notably protected against Gynura segetum-induced HSOS, as observed by reducing serum ALT levels, inhibiting the reduction in CHO and TG levels, and alleviating the histopathological changes. Bicyclol pretreatment inhibited the changes in mRNA levels of CYP450 isozymes (including the increase in CYP2a5 and decrease in CYP2b10, 2c29, 2c37, 3a11, and 7b1). In addition, the upregulation of Bcl-2 and the downregulation of LC3-II/LC3-I proteins expression in HSOS were inhibited with bicyclol pretreatment. CONCLUSION: Bicyclol exerted a protective effect against HSOS induced by Gynura segetum, which could be attributed to the regulated expressions of CYP450 isozymes and alleviated the downregulation of autophagy.

25-Hydroxyvitamin D Serum Levels Linked to Single Nucleotide Polymorphisms (SNPs) (rs2228570, rs2282679, rs10741657) in Skeletal Muscle Aging in Institutionalized Elderly Men Not Supplemented with Vitamin D.

Sarcopenia (Sp) is the loss of skeletal muscle mass associated with aging that results in an involution of muscle function and strength. Vitamin D deficiency is a common health problem worldwide, especially among the elderly, and hypovitaminosis D leads to musculoskeletal disorders. The aim of this study was to evaluate the impact and presence of a possible linkage between Single Nucleotide Polymorphisms (SNPs) CYP2R1 (rs10741657), GC (rs2282679), and VDR (rs2228570), serum 25-OH/D concentrations and the link with the degree of sarcopenia in 19 institutionalized elderly men not supplemented with vitamin D. Levels of 25-OH vitamin D were quantified with a commercial enzyme-linked immunosorbent assay kit and 3 SNPs were genotyped with KASPar assays. Significant differences in 25-OH/D concentration were determined between the bi-allelic combinations of rs228679 and rs228570. We detected statistically significant weak positive correlations between the AA (rs10741657 and rs228570) and TT (rs228679) and alleles and 25-OH/D and the probability of having higher 25-OH/D concentrations was 2- to 3-fold higher. However, the GG alleles of the 3 SNPs showed that the probability of having optimal 25-0H/D concentrations decreases by 32% for rs10741657, 38% for rs228679, and 74% for rs228570, showing a strong negative correlation between the degree of sarcopenia and 25-OH/D levels. Allelic variations in CYP2R1 (rs10741657), GC (rs2282679), and VDR (rs10741657) affect vitamin D levels and decisively influence the degree of sarcopenia in institutionalized elderly people.

Haplotypes in the GC, CYP2R1 and CYP24A1 Genes and Biomarkers of Bone Mineral Metabolism in Older Adults.

Candidate gene studies have analyzed the effect of specific vitamin D pathway genes on vitamin D availability; however, it is not clear whether genetic variants also affect overall bone metabolism. This study evaluated the association between genetic polymorphisms in GC, CYP2R1 and CYP24A1 and serum levels of total 25(OH)D, iPTH and other mineral metabolism biomarkers (albumin, total calcium and phosphorus) in a sample of 273 older Spanish adults. We observed a significant difference between CYP2R1 rs10741657 codominant model and total 25(OH)D levels after adjusting them by gender (p = 0.024). In addition, the two SNPs in the GC gene (rs4588 and rs2282679) were identified significantly associated with iPTH and creatinine serum levels. In the case of phosphorus, we observed an association with GC SNPs in dominant model. We found a relationship between haplotype 2 and 25(OH)D levels, haplotype 4 and iPTH serum levels and haplotype 7 and phosphorus levels. In conclusion, genetic variants in CYP2R1 and GC could be predictive of 25(OH)D and iPTH serum levels, respectively, in older Caucasian adults. The current study confirmed the role of iPTH as one of the most sensitive biomarkers of vitamin D activity in vivo.

Association between Polymorphisms in Vitamin D Pathway-Related Genes, Vitamin D Status, Muscle Mass and Function: A Systematic Review.

An association between vitamin D level and muscle-related traits has been frequently reported. Vitamin D level is dependent on various factors such as sunlight exposure and nutrition. But also on genetic factors. We, therefore, hypothesize that single nucleotide polymorphisms (SNPs) within the vitamin D pathway-related genes could contribute to muscle mass and function via an impact on vitamin D level. However, the integration of studies investigating these issues is still missing. Therefore, this review aimed to systematically identify and summarize the available evidence on the association between SNPs within vitamin D pathway-related genes and vitamin D status as well as various muscle traits in healthy adults. The review has been registered on PROSPERO and was conducted following PRISMA guidelines. In total, 77 studies investigating 497 SNPs in 13 different genes were included, with significant associations being reported for 59 different SNPs. Variations in GC, CYP2R1, VDR, and CYP24A1 genes were reported most frequently, whereby especially SNPs in the GC (rs2282679, rs4588, rs1155563, rs7041) and CYP2R1 genes (rs10741657, rs10766197, rs2060793) were confirmed to be associated with vitamin D level in more than 50% of the respective studies. Various muscle traits have been investigated only in relation to four different vitamin D receptor (VDR) polymorphisms (rs7975232, rs2228570, rs1544410, and rs731236). Interestingly, all of them showed only very low confirmation rates (6-17% of the studies). In conclusion, this systematic review presents one of the most comprehensive updates of the association of SNPs in vitamin D pathway-related genes with vitamin D status and muscle traits in healthy adults. It might be used for selecting candidate SNPs for further studies, but also for personalized strategies in identifying individuals at risk for vitamin D deficiency and eventually for determining a potential response to vitamin D supplementation.

Implication of folate deficiency in CYP2U1 loss of function.

Hereditary spastic paraplegias are heterogeneous neurodegenerative disorders. Understanding of their pathogenic mechanisms remains sparse, and therapeutic options are lacking. We characterized a mouse model lacking the Cyp2u1 gene, loss of which is known to be involved in a complex form of these diseases in humans. We showed that this model partially recapitulated the clinical and biochemical phenotypes of patients. Using electron microscopy, lipidomic, and proteomic studies, we identified vitamin B2 as a substrate of the CYP2U1 enzyme, as well as coenzyme Q, neopterin, and IFN-α levels as putative biomarkers in mice and fluids obtained from the largest series of CYP2U1-mutated patients reported so far. We also confirmed brain calcifications as a potential biomarker in patients. Our results suggest that CYP2U1 deficiency disrupts mitochondrial function and impacts proper neurodevelopment, which could be prevented by folate supplementation in our mouse model, followed by a neurodegenerative process altering multiple neuronal and extraneuronal tissues.

Analysis of the effect of vitamin D supplementation and sex on Vdr, Cyp2r1 and Cyp27b1 gene expression in Wistar rats' tissues.

Vitamin D supplementation is widely recommended for animals and humans. However, its effects on extra-skeletal disorders have not been well proven. Our research aimed to analyse the effect of supplementation with standard and increased doses of vitamin D on the health status, biochemical and haematological parameters of blood as well as on the level of expression of genes metabolising vitamin D and the Vdr gene in the kidney, liver, fat and brain of rats of different sexes. 36 Wistars rats (18 males and 18 females) divided into three supplementation groups (I-O vitamin D, II- 1000 U / kg of vitamin D, III - 5000 U / Kg of vitamin D) were analysed. Vitamin D supplementation had little effect on growth traits and biochemical blood indices; slight decrease in a heart size was observed in females supplemented with high doses of vitamin D (p = 0.0075), moreover male rats tended to have increased level of triglyceride (TG) (p = 0.0516)). In our study we observed that vitamin D supplementation did not change the expression of Vdr gene in any of analysed tissue. However, we noticed evident downregulation of Cyp27b1 gene by vitamin D supplementation in the liver and kidney in a dose-dependent manner. Additionally, we observed that in the female's liver, Vdr and Cyp2r1 were upregulated, in the female's kidney Vdr was upregulated while Cyp27b1 was downregulated compared to males. Moreover, in the female's brain and fat Cyp27b1 and Cyp2r1 tended to be upregulated compared to males. Our results confirm that Vdr and vitamin D metabolising genes are regulated by sex in the kidney and several extra-renal tissues.

Dietary Squalene Induces Cytochromes Cyp2b10 and Cyp2c55 Independently of Sex, Dose, and Diet in Several Mouse Models.

SCOPE: To investigate the effects of squalene, the main hydrocarbon present in extra virgin olive oil, on liver transcriptome in different animal models and to test the influence of sex on this action and its relationship with hepatic lipids. METHODS AND RESULTS: To this purpose, male C57BL/6J Apoe-deficient mice are fed a purified Western diet with or without squalene during 11 weeks and hepatic squalene content is assessed, so are hepatic lipids and lipid droplets. Hepatic transcriptomic changes are studied and confirmed by RT-qPCR. Dietary characteristics and influence of squalene doses are tested in Apoe-deficient on purified chow diets with or without squalene. These diets are also given to Apoa1 and wild-type mice on C57BL/6J background and to C57BL/6J xOla129 Apoe-deficient mice. Squalene supplementation increases its hepatic content without differences among sexes and hormonal status. The Cyp2b10 and Cyp2c55 gene expressions are significantly up-regulated by the squalene intake in all models, with independence of sex, sexual hormones, dietary fat content, genetic background and dose, and in Apoe-deficient mice consuming extra-virgin olive oil. CONCLUSION: Hepatic squalene increases the expression of these cytochromes and their changes in virgin olive oil diets may be due to their squalene content.

Vitamin D in Type 2 Diabetes: Genetic Susceptibility and the Response to Supplementation.

Variants of vitamin D metabolism-genes may predispose to type 2 diabetes (T2D). This study investigated the impact of these variants on disease susceptibility, Vitamin D, parathyroid hormone, C-peptide and HbA1c levels before and after cholecalciferol supplementation in patients with T2D.Twelve polymorphisms within CYP2R1, CYP27B1, DBP, VDR and CYP24A1 were genotyped in 553 T2D patients and 916 controls. In addition 65 patients receiving either cholecalciferol or placebo were analyzed during 6 months intervention and 6 months follow-up.T2D risk alleles are VDR rs7975232 "G" (pc=0.031), rs1544410 "G" (pc=0.027) and CYP2R1 rs10741657 "A" (pc=0.016). Patients with genotypes CYP27B1 rs10877012 "CC" (pc=4x10-5), DBP rs7041 "GG" (pc=0.003), rs4588 "CC" (pc = 3x10-4), CYP24A1 rs2585426 "CG" (pc=0.006) and rs2248137 "CG" (pc=0.001) showed lower 25(OH)D3 and DBP rs4588 "CC" lower 1,25(OH)2D3 levels (pc=0.005). Whereas DBP rs4588 "CC" (pc=0.009), CYP27B1 rs10877012 "AC" (pc=0.059), VDR rs7975323 "AG" (pc=0.033) and rs1544410 "GG" (pc=0.013) are associated with higher 25(OH)D3 levels at 6 months' follow-up. Significant PTH suppression was detected for CYP2R1 "AG" (pc=0.002), DBP rs4588 "CC" (pc<0.001), VDR rs110735810 "CT" (pc<0.001) and CYP24A1 rs2248137 "GG" (pc=0.021).Genetic variants of the vitamin D system predispose to type 2 diabetes and regulate - partially - vitamin D metabolism, concentrations and the vitamin D status. Vitamin D insufficiency is a T2D risk factor. The response to cholecalciferol supplementation can be measured as 25(OH)D3 increment and PTH suppression. This process is regulated by genes of the vitamin D system conferring modest T2D risk.

Vitamin D Metabolism Is Dysregulated in Asthma and Chronic Obstructive Pulmonary Disease.

Rationale: Vitamin D deficiency is common in patients with asthma and chronic obstructive pulmonary disease (COPD). Low 25-hydroxyvitamin D (25[OH]D) levels may represent a cause or a consequence of these conditions.Objectives: To determine whether vitamin D metabolism is altered in asthma or COPD.Methods: We conducted a longitudinal study in 186 adults to determine whether the 25(OH)D response to six oral doses of 3 mg vitamin D3, administered over 1 year, differed between those with asthma or COPD versus control subjects. Serum concentrations of vitamin D3, 25(OH)D3, and 1α,25-dihydroxyvitamin D3 (1α,25[OH]2D3) were determined presupplementation and postsupplementation in 93 adults with asthma, COPD, or neither condition, and metabolite-to-parent compound molar ratios were compared between groups to estimate hydroxylase activity. Additionally, we analyzed 14 datasets to compare expression of 1α,25(OH)2D3-inducible gene expression signatures in clinical samples taken from adults with asthma or COPD versus control subjects.Measurements and Main Results: The mean postsupplementation 25(OH)D increase in participants with asthma (20.9 nmol/L) and COPD (21.5 nmol/L) was lower than in control subjects (39.8 nmol/L; P = 0.001). Compared with control subjects, patients with asthma and COPD had lower molar ratios of 25(OH)D3-to-vitamin D3 and higher molar ratios of 1α,25(OH)2D3-to-25(OH)D3 both presupplementation and postsupplementation (P ≤ 0.005). Intergroup differences in 1α,25(OH)2D3-inducible gene expression signatures were modest and variable if statistically significant.Conclusions: Attenuation of the 25(OH)D response to vitamin D supplementation in asthma and COPD associated with reduced molar ratios of 25(OH)D3-to-vitamin D3 and increased molar ratios of 1α,25(OH)2D3-to-25(OH)D3 in serum, suggesting that vitamin D metabolism is dysregulated in these conditions.

Associations between common polymorphisms in CYP2R1 and GC, Vitamin D intake and risk of colorectal cancer in a prospective case-cohort study in Danes.

BACKGROUND: The association between vitamin D and incidence of colorectal cancer has been thoroughly investigated, but the results are conflicting. The objectives in this study were to investigate whether two functional polymorphisms in GC and CYP2R1, respectively, previously shown to predict vitamin D concentrations, were associated with risk of colorectal cancer; and further, to assess gene-environment interaction between the polymorphisms and intake of vitamin D through diet and supplementation in relation to risk of colorectal cancer. METHODS: A nested case-cohort study of 920 colorectal cancer cases and 1743 randomly selected participants from the Danish prospective "Diet, Cancer and Health" study was performed. Genotypes CYP2R1/rs10741657 and GC/rs4588 were determined by PCR-based KASP™ genotyping assay. Vitamin D intake from supplements and diet was assessed from a validated food frequency questionnaire. Incidence rate ratios were estimated by the Cox proportional hazards model, and interactions between polymorphisms in GC and CYP2R1 and vitamin D intake in relation to risk of colorectal cancer were assessed. RESULTS: Neither of the two polymorphisms was associated with risk of colorectal cancer per se. Heterozygote carriage of CYP2R1/rs10741657 and GC/rs4588, and carriage of two risk alleles (estimated by a genetic risk score) were weakly associated with 9-12% decreased risk of colorectal cancer per 3 µg intake of vitamin D per day (IRRCYP2R1/rs10741657 = 0.88, 95% CI: 0.79-0.97; IRRGC/rs4588 = 0.91, 95% CI: 0.82-1.01, IRRGRS2 = 0.90, 95% CI: 0.81-0.99). CONCLUSIONS: The results suggest that genetic variation in vitamin D metabolising genes may influence the association between vitamin D intake, through food and supplementation, and risk of colorectal cancer. CLINICAL TRIAL REGISTRY: NCT03370432. Registered 12 December 2017 (retrospectively registered).

Genetic Polymorphisms in the Vitamin D Pathway and Non-small Cell Lung Cancer Survival.

Various genetic polymorphisms have been linked to lung cancer susceptibility and survival outcomes. Vitamin D (VD) regulates cell proliferation and differentiation, inhibits tumor growth and induces apoptosis. Observations from several previous studies including our own suggest that genetic polymorphisms in the VD pathway may be associated with lung cancer risk. The aim of this study is to assess if genetic polymorphisms in the VD pathway are associated with the prognosis of non-small cell lung cancer (NSCLC). Nine single nucleotide polymorphisms (SNPs) in five genes in the VD pathway were genotyped with the TaqMan assays in 542 patients with primary NSCLC, and the relationships between these SNPs and overall survival were evaluated. We found that SNP rs10741657 in the CYP2R1 gene was associated with the prognosis of NSCLC, especially in elderly patients and not being treated with chemotherapy. Some of the VD pathway-related genetic polymorphisms may influence the prognosis of NSCLC. More research is needed to further confirm the finding and test if VD supplements can be used for NSCLC treatment.

PPARα ligand, AVE8134, and cyclooxygenase inhibitor therapy synergistically suppress lung cancer growth and metastasis.

BACKGROUND: Lung cancer (LC) is one of the leading causes of death worldwide, which highlights the urgent need for better therapies. Peroxisome proliferator-activated nuclear receptor alpha (PPARα), known as a key nuclear transcription factor involved in glucose and lipid metabolism, has been also implicated in endothelial proliferation and angiogenesis. However, the effects and potential mechanisms of the novel PPARα ligand, AVE8134, on LC growth and progression remain unclear. METHODS: A subcutaneous tumour was established in mice by injecting TC-1 lung tumour cells (~ 1 × 106 cells) into their shaved left flank. These mice were treated with three different PPARα ligands: AVE8134 (0.025% in drinking water), Wyeth-14,643 (0.025%), or Bezafibrate (0.3%). Tumour sizes and metastasis between treated and untreated mice were then compared by morphology and histology, and the metabolites of arachidonic acid (AA) were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Inhibition of either Cyp2c44 expression by genetic disruption or cyclooxygenase (COX) activity by indomethacin was used to test the mechanisms by which AVE8134 affects tumour growth. RESULTS: The pharmacodynamics effects of AVE8134, Wyeth-14,643, and Bezafibrate on lipids control were similar. However, their effects on tumour suppression were different. Eicosanoid profile analysis showed that all PPARα ligands reduced the production of AA-derived epoxyeicosatrienoic acids (EETs) and increased the hydroxyl product, 11-hydroxyeicosatetraenoic acids (11-HETE). Moreover, increased 11-HETE promoted endothelial proliferation, angiogenesis, and subsequent tumour deterioration in a dose-dependent manner possibly via activating the AKT/extracellular signal-regulated kinase (ERK) pathway. The increased 11-HETE partly neutralized the benefits provided by the Cyp2c44-EETs system inhibited by PPARα ligands in tumour-bearing mice. AVE8134 treatment worsened the tumour phenotype in Cyp2c44 knockout mice, indicating that AVE8134 has contradictory effects on tumour growth. The COX inhibitor indomethacin strengthened the inhibitory actions of AVE8134 on tumour growth and metastasis by inhibiting the 11-HETE production in vivo and in vitro. CONCLUSION: In this study, we found that the degrees of inhibition on LC growth and metastasis by PPARα ligands depended on their bidirectional regulation on EETs and 11-HETE. Considering their safety and efficacy, the novel PPARα ligand, AVE8134, is a potentially ideal anti-angiogenesis drug for cancer treatment when jointly applied with the COX inhibitor indomethacin.

Genetic variation in GC and CYP2R1 affects 25-hydroxyvitamin D concentration and skeletal parameters: A genome-wide association study in 24-month-old Finnish children.

Vitamin D is important for normal skeletal homeostasis, especially in growing children. There are no previous genome-wide association (GWA) studies exploring genetic factors that influence vitamin D metabolism in early childhood. We performed a GWA study on serum 25-hydroxyvitamin D (25(OH)D) and response to supplementation in 761 healthy term-born Finnish 24-month-old children, who participated in a randomized clinical trial comparing effects of 10 µg and 30 µg of daily vitamin D supplementation from age 2 weeks to 24 months. Using the Illumina Infinium Global Screening Array, which has been optimized for imputation, a total of 686085 markers were genotyped across the genome. Serum 25(OH)D was measured at the end of the intervention at 24 months of age. Skeletal parameters reflecting bone strength were determined at the distal tibia at 24 months using peripheral quantitative computed tomography (pQCT) (data available for 648 children). For 25(OH)D, two strong GWA signals were identified, localizing to GC (Vitamin D binding protein) and CYP2R1 (Vitamin D 25-hydroxylase) genes. The GWA locus comprising the GC gene also associated with response to supplementation. Further evidence for the importance of these two genes was obtained by comparing association signals to gene expression data from the Genotype-Tissue Expression project and performing colocalization analyses. Through the identification of haplotypes associated with low or high 25(OH)D concentrations we used a Mendelian randomization approach to show that haplotypes associating with low 25(OH)D were also associated with low pQCT parameters in the 24-month-old children. In this first GWA study on 25(OH)D in this age group we show that already at the age of 24 months genetic variation influences 25(OH)D concentrations and determines response to supplementation, with genome-wide significant associations with GC and CYP2R1. Also, the dual association between haplotypes, 25(OH)D and pQCT parameters gives support for vertical pleiotropy mediated by 25(OH)D.

The Association between Polymorphisms of Vitamin D Metabolic-Related Genes and Vitamin D3 Supplementation in Type 2 Diabetic Patients.

OBJECTIVE: To investigate the effect of single nucleotide polymorphisms (SNPs) of the key genes in vitamin D metabolic pathway on the serum 25(OH)D level after long-term vitamin D3 supplementation and provide a theoretical basis for rational vitamin D3 supplementation in diabetic patients with different genetic backgrounds. METHODS: Patients with type 2 diabetes (T2DM) who met the inclusive criteria were given 800 IU of vitamin D3 daily for 30 consecutive months. Serum 25(OH)D levels was measured at enrollment and every 6 months after enrollment. The average value of four-time measurements represented individual serum 25(OH)D level during vitamin D3 supplementation. Multiplex TaqMan genotyping was used to determine the distribution of eight candidate SNPs in genes of DHCR7, CYP2R1, CYP27B1, CYP24A1, and VDR, which are key genes in the vitamin D metabolic pathway, in diabetic patients. RESULTS: At baseline, the average serum 25(OH)D level was 22.71 ± 6.87 ng/mL, and 17.9% of patients had a ≥30 ng/mL level. During supplementation, the level of 25(OH)D increased significantly at each time point, and the average 25(OH)D level increased to 30.61 ± 5.04 ng/mL; however, there were 44.6% of patients whose serum 25(OH)D levels were still below 30 ng/mL. In the patients with CYP27B1 (rs10877012) G/T genotype, 71.79% achieved sufficient level of 25(OH)D, which was significantly higher than the other two genotypes (P < 0.05). Compared with those with T/T genotype, the RR of the patients with rs10877012 for <30 ng/mL level was 0.544 (95% CI: 0.291-0.917), and the RR after adjusting age and outdoor activity was 0.560 (95% CI: 0.292-0.970). CONCLUSION: The serum 25(OH)D level in patients with diabetes mellitus after long-term vitamin D3 supplementation is associated with CYP27B1 polymorphism. Patients with rs10877012 G/T allele have a better response to vitamin D3 supplementation. TRIAL REGISTRATION: This trial is registered with ChiCTR-IPC-17012657.

Common Polymorphisms in Genes Related to Vitamin D Metabolism Affect the Response of Cognitive Abilities to Vitamin D Supplementation.

It is possible that vitamin D acts as a neurosteroid and that vitamin D deficiency may have an adverse impact on brain function and cognitive function. There are a few reports that have demonstrated an association between polymorphisms of genes involved in vitamin D metabolism and neurodegenerative disease. We aimed to evaluate the relationship between common, functional vitamin D-associated gene variants and cognitive abilities and to investigate the effect size of this polymorphism on cognitive capabilities associated with high-dose vitamin D supplementation. A total of 319 healthy adolescents received a high dose of vitamin D (50,000 IU)/week for 9 weeks. A questionnaire was used to assess cognitive abilities at baseline and after treatment. The genotypes of the CYP2R1-rs10766197 and GC-rs4588 variants were determined using TaqMan genotyping techniques. At baseline, total cognitive ability scores were higher in the AA group who were homozygous for the uncommon allele, compared with the other (AG and GG) genotypes of the CYP2R1-rs10766197 polymorphism (104.9 ± 27.8 vs. 79.1 ± 38.8 vs. 73.1 ± 25.6; p < 0.001, respectively). During the supplementation period, cognitive ability scores increased in individuals with the AG and GG genotypes, while individuals with a AA genotype did not show significant change in total score after intervention (p = 0.17). For GC SNP (rs4588), no major differences at baseline and trial-net change of cognitive tasks score were observed between the genotypes under three genetic models (pSNP = 0.67). Vitamin D supplements have trait-dependent effects on cognitive performance that suggests a causal role for vitamin D in cognitive performance. The rs10766197 variant, near the CYP2R1 gene locus, significantly modified the efficacy of high-dose vitamin D3 supplementation for its effects on improving cognitive abilities indicate that some subjects might require a higher dose to benefit from in terms of cognitive performance.

A variant in CYP2R1 predicts circulating vitamin D levels after supplementation with high-dose of vitamin D in healthy adolescent girls.

AIM: The determinants of serum vitamin D seems to be the environmental factors (dietary and supplementary intake and exposure to ultraviolet light) and genetic factors. We aimed to study the relationship between a vitamin D-associated genetic polymorphism and serum 25(OH)D concentrations in healthy adolescent girls in Iran, and its effects on a high-dose supplement of vitamin D. MATERIAL AND METHOD: A total of 616 healthy adolescent girls with mean age 15 received 50,000 IU of vitamin D3 weekly over 9 weeks. Serum vitamin D levels and other metabolic factors were measured at baseline and after the intervention. The genotyping of the CYP2R1 variant (rs10741657) was performed by TaqMan genotyping assays. RESULTS: Regardless of the genetic background, at baseline, 87% of adolescent girls were vitamin D deficient (serum 25(OH)D level < 50 nmol/l). High-dose supplementation with VitD reduced the proportion of girls who were deficient substantially to about 24%. The genetic analysis revealed that although at baseline there was not a gene-vitamin D association ( p trend = 0.1), the response to supplementation appeared to be modulated by this variant ( p trend < 0.001). However, other anthropometric and biochemical measures were not affected by this intervention, over this short period. Serum 25(OH)D was increased in all participants although the carriers of the minor A allele seemed to be better responders so that the percentages of the change serum vitamin D in the holder of AA and AG genotypes were 539.4 ± 443.1 and 443.7 ± 384.6, respectively, compared with those with common GG genotype (363.3 ± 354.0). Our regression analysis revealed that the probability of an increase in serum 25(OH)D in a participant with AA genotype was 2.5-fold greater than those with a GG genotype (OR = 2.5 (1.4-4.4); p value = 0.002). CONCLUSION: Based on our findings, it appears that the rs10741657 variant of the CYP2R1 gene modulates the response to high-dose of vitamin D supplementation.

A genetic variant in the cytochrome P450 family 2 subfamily R member 1 determines response to vitamin D supplementation.

BACKGROUND: Globally, about 1 billion people have inadequate levels of serum vitamin D and it is prevalent in all ethnicities and age groups. Few foods naturally contain sufficient vitamin D; therefore, most people get their requirements through supplementation. Hence vitamin D status is affected by genetic and environmental determinants including season of measurement, diet habitual, health status, body mass index and concurrent medication. Further studies are necessary to understand how genetic variation influences vitamin D metabolism. We aimed to explore the association between a potential vitamin D-related polymorphism (the rs10766197 polymorphism in the CYP2R1 gene) with the response to supplementation of vitamin D in 253 healthy Iranian girls. MATERIAL AND METHOD: A total of 253 healthy subjects received 50,000 IU of vitamin D3 weekly for 9 weeks. Serum 25(OH)D concentrations and metabolic profiles were measured at baseline and after 9 weeks of supplementation. The genotypes of the CYP2R1 variant (rs10766197) were identified using TaqMan genotyping assays. RESULTS: Serum 25(OH)D during the supplementation, increased in all individuals. Subjects with a AA major genotype at this locus had higher vitamin D concentrations after intervention (Changes (%) 448.4% ± 425% in AA vs 382.7% ± 301% in GG). This genetic variant modulated the response to supplementation (p < 0.001 and p-value SNP = 0.05). Regression analysis showed that the probability of affecting serum 25(OH)D, in individuals who had homozygous major allele GG was two-fold higher than carriers of the uncommon allele A (OR = 2.1 (1-4.2); p = 0.03). Interestingly, the Hs-CRP was reduced in AA carries while was elevated in individuals with GG and AG genotypes, after high-dose vitamin D supplementation. CONCLUSION: Changes in serum vitamin D and metabolic profile following high dose supplementation with vitamin D were associated with CYP2R1 polymorphism. Although carriers of the common G allele showed a greater response in the serum vitamin D.

Customised in vitro model to detect human metabolism-dependent idiosyncratic drug-induced liver injury.

Drug-induced liver injury (DILI) has a considerable impact on human health and is a major challenge in drug safety assessments. DILI is a frequent cause of liver injury and a leading reason for post-approval drug regulatory actions. Considerable variations in the expression levels of both cytochrome P450 (CYP) and conjugating enzymes have been described in humans, which could be responsible for increased susceptibility to DILI in some individuals. We herein explored the feasibility of the combined use of HepG2 cells co-transduced with multiple adenoviruses that encode drug-metabolising enzymes, and a high-content screening assay to evaluate metabolism-dependent drug toxicity and to identify metabolic phenotypes with increased susceptibility to DILI. To this end, HepG2 cells with different expression levels of specific drug-metabolism enzymes (CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, GSTM1 and UGT2B7) were exposed to nine drugs with reported hepatotoxicity. A panel of pre-lethal mechanistic parameters (mitochondrial superoxide production, mitochondrial membrane potential, ROS production, intracellular calcium concentration, apoptotic nuclei) was used. Significant differences were observed according to the level of expression and/or the combination of several drug-metabolism enzymes in the cells created ad hoc according to the enzymes implicated in drug toxicity. Additionally, the main mechanisms implicated in the toxicity of the compounds were also determined showing also differences between the different types of cells employed. This screening tool allowed to mimic the variability in drug metabolism in the population and showed a highly efficient system for predicting human DILI, identifying the metabolic phenotypes associated with increased DILI risk, and indicating the mechanisms implicated in their toxicity.

Daikenchuto (TU-100) alters murine hepatic and intestinal drug metabolizing enzymes in an in vivo dietary model: effects of gender and withdrawal.

Herbal medicines and natural products used for maintenance of health or treatment of diseases have many biological effects, including altering the pharmacokinetics and metabolism of other medications. Daikenchuto (TU-100), an aqueous extract of ginger, ginseng, and Japanese green pepper fruit, is a commonly prescribed Kampo (Japanese herbal medicine) for postoperative ileus or bloating. The effects of TU-100 on drug metabolism have not been investigated. In this study, we analyzed the effect of TU-100 on expression of key drug-metabolizing enzymes (DMEs) and drug transporters (DTs) in murine liver and gastrointestinal tract using a dietary model. Liver, jejunum, and proximal colon were analyzed for phase I and II DMEs and DT mRNA expression by reverse transcription (RT) first by nonquantitative and followed by quantitative polymerase chain reaction (PCR) and protein expression. Liver, jejunum, and proximal colon expressed some identical but also unique DMEs and DTs. TU-100 increased the greatest changes in cytochrome (Cyp) 2b10 and Cyp3a11 and Mdr1a. Basal and TU-100 stimulated levels of DME and DT expression were gender-dependent, dose-dependent and reversible after cessation of TU-100 supplementation, except for some changes in the intestine. Quantitative Western blot analysis of protein extracts confirmed the quantitative PCR results.