Association of vitamin D receptor gene polymorphisms with type 2 diabetes mellitus in Taif population: a case-control study

Several reasons may underlie the dramatic increase in type2 diabetes mellitus. One of these reasons is the genetic basis and variations. Vitamin D receptor polymorphisms are associated with different diseases such as rheumatoid arthritis and diabetes. The aim of this study is to investigate the possible association of two identified mutations ApaI (rs7975232) and TaqI (rs731236). Eighty-nine healthy individuals and Fifty-six Type 2 Diabetic (T2D) patients were investigated using RFLP technique for genotyping and haplotyping as well. The distribution of Apal genotypes was not statistically significant among the control (P=0.65) as well as for diabetic patients (P=0.58). For Taql allele frequencies of T allele was 0.61 where of G allele was 0.39. The frequency distribution of Taql genotypes was not statistically significant among the control (P=0.26) as well as diabetic patients (P=0.17). Relative risk of the allele T of Apa1 gene is 1.28 and the odds ratio of the same allele is 1.53, while both estimates were < 1.0 of the allele G. Similarly, with the Taq1 gene the relative risk and the odds ratio values for the allele T are 1.09 and 1.27 respectively and both estimates of the allele C were 0.86 for the relative risk and 0.79 for the odds ratio. The pairwise linkage disequilibrium between the two SNPs Taq1/apa1 was statistically significant in control group (D = 0.218, D' = 0.925 and P value < 0.001) and similar data in diabetic groups (D = 0.2, D' = 0.875 and P value < 0.001). These data suggest that the T allele of both genes Apa1 and Taq1 is associated with the increased risk of type 2 diabetes. We think that we need a larger number of volunteers to reach a more accurate conclusion.

Vitamin D Receptor (VDR) Gene Polymorphisms Modify the Response to Vitamin D Supplementation: A Systematic Review and Meta-Analysis

The vitamin D receptor (VDR), a member of the nuclear receptor superfamily of transcriptional regulators, is crucial to calcitriol signalling. VDR is regulated by genetic and environmental factors and it is hypothesised that the response to vitamin D supplementation could be modulated by genetic variants in the VDR gene. The best studied polymorphisms in the VDR gene are Apal (rs7975232), BsmI (rs1544410), Taql (rs731236) and Fokl (rs10735810). We conducted a systematic review and meta-analysis to evaluate the response to vitamin D supplementation according to the BsmI, TaqI, ApaI and FokI polymorphisms. We included studies that analysed the relationship between the response to vitamin D supplementation and the genotypic distribution of these polymorphisms. We included eight studies that enrolled 1038 subjects. The results showed no significant association with the BsmI and ApaI polymorphisms (p = 0.081 and p = 0.63) and that the variant allele (Tt+tt) of the TaqI polymorphism and the FF genotype of the FokI variant were associated with a better response to vitamin D supplementation (p = 0.02 and p < 0.001). In conclusion, the TaqI and FokI polymorphisms could play a role in the modulation of the response to vitamin D supplementation, as they are associated with a better response to supplementation.

Vitamin D receptor gene polymorphism predicts left ventricular hypertrophy in maintenance hemodialysis

Background To verify that the single nucleotide polymorphisms (SNP) of vitamin D receptor (VDR) may lead to genetic susceptibility to left ventricular hypertrophy (LVH), the present study was designed to study four SNPs of VDR associated with LVH in maintenance hemodialysis (MHD) patients of Han nationality. Methods 120 MHD patients were recruited at Department of Nephrology, Zhongnan Hospital of Wuhan University to analyze the expression of genotype, allele and haplotype of Fok I, Bsm I, Apa I and Taq I in blood samples, and to explore their correlation with blood biochemical indexes and ventricular remodeling. Results The results showed that the risks of CVD included gender, dialysis time, heart rate, SBP, glycated hemoglobin, calcium, iPTH and CRP concentration. Moreover, LAD, LVDd, LVDs, IVST and LVMI in B allele of Bsm I increased significantly. Fok I, Apa I and Taq I polymorphisms have no significant difference between MHD with LVH and without LVH. Further study showed that VDR expression level decreased significantly in MHD patients with LVH, and the B allele was positively correlated with VDR Expression. Conclusion VDR Bsm I gene polymorphism may predict cardiovascular disease risk of MDH patients, and provided theoretical basis for early detection and prevention of cardiovascular complications.

Lithocholic Acid Amides as Potent Vitamin D Receptor Agonists

1α,25-Dihydroxyvitamin D3 [1α,25(OH)2D3, 1] is an active form of vitamin D3 and regulates various biological phenomena, including calcium and phosphate homeostasis, bone metabolism, and immune response via binding to and activation of vitamin D receptor (VDR). Lithocholic acid (LCA, 2) was identified as a second endogenous agonist of VDR, though its potency is very low. However, the lithocholic acid derivative 3 (Dcha-20) is a more potent agonist than 1α,25(OH)2D3, (1), and its carboxyl group has similar interactions to the 1,3-dihydroxyl groups of 1 with amino acid residues in the VDR ligand-binding pocket. Here, we designed and synthesized amide derivatives of 3 in order to clarify the role of the carboxyl group. The synthesized amide derivatives showed HL-60 cell differentiation-inducing activity with potency that depended upon the substituent on the amide nitrogen atom. Among them, the N-cyanoamide 6 is more active than either 1 or 3.

Daily Soy–Catfish–Anchovy–Rice (SCAR) Porridge Increases 25(OH)D Serum Levels in Tuberculosis Patients with Vitamin D Receptor Gene Polymorphisms

BACKGROUND: The presence of vitamin D receptor (VDR) polymorphism and high levels of inflammatory markers are predisposing factors indicating disease progression and malnutrition. To meet nutritional needs in maintaining nutritional status in tuberculosis patients with VDR gene polymorphisms (TaqI or FokI), food that is easily absorbed and high in vitamin D, calcium, and protein is needed. This study was conducted to determine whether high vitamin D and calcium porridge called soy–catfish–anchovy–rice (SCAR) porridge would increase 25(OH)D serum levels and other parameters, including calcium, albumin, high-sensivity C-reactive protein (hs-CRP), and blood glucose serum levels.METHODS: The study was a parallel, open, clinical trial. There were 22 subjects in the intervention (I) group who received 50 g of SCAR porridge once per day along with dietary counseling, and 21 subjects in the control (C) group who only received dietary counseling. All subjects with TC and CC (TaqI) or TC and CC (FokI) genotype were included in this study. The intervention lasted for 14 days, and the parameters such as 25(OH)D, calcium, albumin, hs-CRP, and blood glucose serum levels were assessed before and after intervention between groups.RESULTS: All subjects in both groups completed the study. After 14 days of intervention, there was a significant increase in 25(OH)D (p=0.01) and decrease in hs-CRP (p=0.02) serum levels in the I group, and no change was observed in the C group. There was no significant difference in albumin and blood glucose serum levels.CONCLUSION: The results show that 50 g of SCAR porridge per day for 14 days is an effective supplementation that can increase 25(OH)D and decrease hs-CRP serum levels in tuberculosis patients with VDR gene polymorphism.KEYWORDS: vitamin D, hs-CRP, polymorphism, porridge