Association between the vitamin D receptor gene polymorphism and osteoporosis

Pro-Osteogenic Effect of the Nutraceutical BlastiMin Complex® in Women with Osteoporosis or Osteopenia: An Open Intervention Clinical Trial

Osteoporosis is a chronic disease that affects millions of patients worldwide and is characterized by low bone mineral density (BMD) and increased risk of fractures. Notably, natural molecules can increase BMD and exert pro-osteogenic effects. Noteworthily, the nutraceutical BlastiMin Complex® (Mivell, Italy, European Patent Application EP4205733A1) can induce differentiation of human bone marrow mesenchymal stem cells (BM-MSCs) in osteoblasts and can exert in vitro pro-osteogenic and anti-inflammatory effects. Thus, the purpose of this study was to verify the effects of BlastiMin Complex® on bone turnover markers (BTMs) and BMD in patients with senile and postmenopausal osteopenia or osteoporosis. The efficacy of BlastiMin Complex® on BTMs in serum was evaluated through biochemical assays. BMD values were analyzed by dual-energy X-ray absorptiometry (DXA) and Radiofrequency Echographic Multi Spectrometry (R.E.M.S.) techniques, and the SNPs with a role in osteoporosis development were evaluated by PCR. Clinical data obtained after 12 months of treatment showed an increase in bone turnover index, a decrease in C-reactive protein levels, and a remarkable increase in P1NP levels, indicating the induction of osteoblast proliferation and activity in the cohort of 100% female patients recruited for the study. These findings show that the nutraceutical BlastiMin Complex® could be used as an adjuvant in combination with synthetic drugs for the treatment of osteoporosis pathology.

VDR Gene Polymorphisms (BsmI, FokI, TaqI, ApaI) in Total Hip Arthroplasty Outcome Patients

A total hip arthroplasty (THA) can improve quality of life, but loosening of the hip prosthesis is a complex problem in which vitamin D may also play a role. The Vitamin D Receptor (VDR) is involved in the response of cells to the action of vitamin D, and its genetic variability raises the question of whether individual differences could influence the risk of prosthesis loosening. The aim of this study was to investigate the relationship between VDR single nucleotide polymorphisms (SNPs) (ApaI, BsmI, FokI and TaqI) and the serum VDR and 25(OH)D levels in three groups of patients: (1) arthroscopy patients after THA without loosening of the prosthesis (CA-Control Arthroplasty), (2) patients after THA with loosened hip prostheses (L-Loosening) and (3) the control group (C-Control). Our results suggest that the genotypes tt of TaqI, BB of BsmI, and FF of FokI may influence the VDR effect in patients with loosened protheses. Our results showed that the ACAC haplotype (AtBF) was over two times more frequent in the L group than in CA + C: OR =2.35 [95% CI 1.44-3.83; p = 0.001]. There was no significant correlation between the VDR and serum 25(OH)D levels, but there were differences between studied groups.

A Case-Control Study of the Fokl Polymorphism of the Vitamin D Receptor Gene in Bulgarians With Lumbar Disc Herniation

BACKGROUND

The present study investigates whether vitamin D receptor (VDR) gene polymorphisms play a role in intervertebral disc degeneration (IDD), a common cause of low back pain (LBP) and reduced quality of life. Specifically, we examined the FokI VDR polymorphism and its potential association with lumbar disc herniation (LDH) in patients from Bulgaria. Previous studies have suggested a link between mutations in the VDR gene and IDD.

METHODS

We investigated whether a potential connection between VDR polymorphisms and LDH was present by comparing the FokI polymorphism of 60 selected patients (25 to 60) with LDH and 60 healthy volunteers within the same age range. We used polymerase chain reaction to assess the phenotype of the examined subjects and statistical tests to evaluate whether the obtained results were statistically significant.

RESULTS

The performed genetic and statistical analyses reviewed significant differences in genotypic frequencies between the patient group and healthy volunteers. The frequency of the F allele is notably higher in patients with LDH (80%) compared to volunteers (52%), while the f allele is more common among patients (86.6%) than volunteers (100%).

CONCLUSION

This study strongly suggests that expression of the F allele of the VDR gene may increase the susceptibility of developing LDH, while having the f allele could potentially have a protective effect. Our results shed light on the underlying complex mechanisms contributing to the development of LDH.

Impact of leptin or melatonin on Sema4D overexpression-related bone metabolism

PURPOSE

The current study aims to investigate the regulatory impact of leptin or melatonin on bone metabolism as well as the underlying mechanism in conjunction with Sema4D (monoclonal antibody to semaphorin 4D).

METHODS

Rats were used to create the osteoporosis model utilizing the OVX (OVariectomize) technique. Rat tibial specimens from each side were collected for three-dimensional reconstruction and Micro-CT scanning examination. The Hematoxylin-osinstaining (HE) staining technique was used to determine the pathological condition of bone tissues. The ELISA (Enzyme-Linked Immunosorbent Assay) assay was used to measure the amount of estradiol present in the serum. In the current study, there were six groups: control, OVX, OVX + NL (no load group), OVX + Sema4D, OVX + Sema4D + leptin, and OVX + Sema4D + MT (melatonin). Rats were given injections of the Sema4D or leptin overexpressing vectors via the tail vein in accordance with the aforementioned classification. By using a high-resolution micro-CT technology, 3D bone structure was discovered. The activity of tartrate-resistant acid phosphatase-5b (TRAP-5b) and bone-derived alkaline phosphatase (BALP) in serum was assessed using an ELISA. The number of osteoclasts in the metaphysis of the upper tibia was determined using TRAP (tartrate-resistant acid phosphatase) staining. Immunohistochemistry was used to find leptin and bone morphogenetic protein-2 (BMP-2) expressions in bone tissue.

RESULTS

The BV/TV (Bone volume/Tissue volume), Tb.N (Trabecular number), BMD (Bone Mineral Density), and BMC (Bone Mineral Content) levels were significantly higher in the OVX + Sema4D + leptin and OVX + Sema4D + MT groups compared to OVX + NL, while Tb.Sp (Trabecular separation) levels were significantly lower. In contrast to the OVX group, the bone trabeculae in the OVX + Sema4D + leptin and OVX + Sema4D + MT groups had a relatively complete structure and tended to be organized closely. The amount of bone trabeculae grew drastically, whereas the proportion of TRAP-positive osteoclasts declined dramatically. BMP-2 and leptin were also elevated, while BALP and TRAP-5b activity was reduced.

CONCLUSION

Leptin or melatonin improved Sema4d's role in trabecular bone microstructure, bone production, and repairment of trabecular bone loss in osteoporosis rats.

A cross-sectional study to find association of VDR gene polymorphism with non-syndromic congenital ichthyosis and with vitamin D deficiency

Though development of vitamin D deficiency and rickets in patients with congenital ichthyosis (CI) have recently been observed, yet exact cause of such association is not properly understood. To evaluate association between Vitamin D Receptor (VDR) polymorphism and CI, and to identify risk factors responsible for development of vitamin D deficiency in ichthyosis. In this cross-sectional study, detailed history of patients and controls was noted and certain biochemical investigations were made. Immunohistochemical staining of skin tissue was done for VDR expression in epidermal and dermal region of ichthyosis patients. VDR polymorphism was assessed in all participants. Ninety-six subjects, were recruited. Mean serum vitamin D was significantly lower among ichthyosis patients. Cdx-2 polymorphism was found to be significantly associated with ichthyosis (p = 0.009). Within the diseased group, Fok-1 (p = 0.035), age (p = 0.020) and alkaline phosphatase (ALP) (p = 0.007) emerged as factors which might be associated with vitamin D deficiency. Cdx2 polymorphism was significantly associated with CI patients. Also, association of Fok-1 polymorphism along with age and raised serum ALP levels emerged as potential factors for determining CI-related vitamin D deficiency.

Vitamin D Receptor Gene Polymorphisms Affect Osteoporosis-Related Traits and Response to Antiresorptive Therapy

The present study analyzed the effect of vitamin D receptor (VDR) gene polymorphisms (ApaI, TaqI, BsmI, FokI, and Cdx2) on bone mineral density (BMD), biochemical parameters and bone turnover markers, fracture prevalence, and response to three types of antiresorptive therapy (estrogen-progesterone, raloxifene, and ibandronate) in 356 postmenopausal women from Slovakia. Association analysis revealed a significant effect of BsmI polymorphism on lumbar spine BMD, serum osteocalcin (OC), and β-CrossLaps levels. While ApaI and Cdx2 polymorphisms were associated with OC and alkaline phosphatase, TaqI polymorphism affected all turnover markers. ApaI, TaqI, and BsmI genotypes increased the risk of spinal, radial, or total fractures with odds ratios ranging from 2.03 to 3.17. Each of therapy types evaluated had a beneficial effect on all osteoporosis-related traits; however, the VDR gene affected only ibandronate and raloxifene treatment. ApaI/aa, TaqI/TT, and BsmI/bb genotypes showed a weaker or no response to ibandronate therapy in femoral and spinal BMD. The impact of aforementioned polymorphisms on turnover markers was also genotype dependent. On the contrary, only TaqI and BsmI polymorphisms influenced raloxifene therapy, even only in lumbar spine BMD. These results point to the potential of using the VDR gene in personalized pharmacotherapy of osteoporosis.

Possible Association Between Polymorphisms in ESR1, COL1A2, BGLAP, SPARC, VDR, and MMP2 Genes and Dental Fluorosis in a Population from an Endemic Region of West Bengal

Dental fluorosis (DF) is the most prevalent form of fluorosis in India affecting millions of people all over the country. As estrogen receptor 1 (ESR1), collagen type 1 alpha 2 (COL1A2), bone γ-carboxyglutamic acid protein (BGLAP), secreted protein acidic and cysteine-rich (SPARC), vitamin D receptor (VDR), and matrix metallopeptidase 2 (MMP2) genes play critical roles in bone metabolism, bone formation, mineral metabolism, and mineralization, variants in these genes could influence susceptibility to DF. The present study was aimed at evaluating the association between 15 single-nucleotide polymorphisms (SNPs) in the six candidate genes (namely, ESR1, COL1A2, BGLAP, SPARC, VDR, and MMP2) and DF among 132 individuals (case = 71 and control = 61) living in a fluoride endemic region of West Bengal, India. No statistically significant association with disease risk was found when the genotypes and allele frequencies of each of the 15 SNPs was analyzed individually using odd's ratio with 95% confidence interval. "CC" and "AG" haplotypes of the COL1A2 gene showed a borderline association with DF. The present study is the first in India to use multifactor dimensionality reduction (MDR) analysis for identifying gene-gene and gene-environment interactions in fluorosis. The biomarker of serum fluoride showed a significant association with the disease state among the 17 attributes (15 SNPs and 2 biomarkers of urine fluoride and serum fluoride) (P value = 0.011). The best model of MDR analysis with maximized testing accuracy involved two SNPs from the ESR1 gene (rs9340799 and rs2077647) and one SNP from BGLAP gene (rs1543294) (P value < 0.0001).

Vitamin D in dairy cows: metabolism, status and functions in the immune system

The function of vitamin D in calcium homoeostasis in dairy cows, such as in other vertebrates, is known for many years. In recent years, new and interesting, non-classical functions of vitamin D have been elucidated, including effects on the immune system. The major aim of this review is to provide an overview of effects of vitamin D or its metabolites on the immune system in dairy cows. The first part of the review provides an overview of vitamin D metabolism, with particular reference to the role of various proteins (25- and 1-hydroxylases, vitamin D binding protein, vitamin D receptor) in vitamin D signalling. The second part deals with the role of the concentration of 25-hydroxyvitamin D [25(OH)D] in plasma as an indicator of the vitamin D status in dairy cows, and its dependence on sunlight exposure and dietary vitamin D supplementation. In this part also the "free hormone hypothesis" is discussed, indicating that the concentration of free 25(OH)D might be a more valid indicator of the vitamin D status than the concentration of total 25(OH)D. The third part deals with classical and the non-classical functions of vitamin D. Among the non-classical functions which are based on an autocrine vitamin D signalling, particular reference is given to the effects of vitamin D and vitamin D metabolites on the immune system in bovine immune cells and in dairy cows. Recent findings provide some indication that vitamin D or its metabolite 25(OH)D could enhance the immune function in dairy cows and be useful for the prevention and therapy of mastitis. However, the number of studies reported so far in this respect is very limited. Thus, much more research is required to yield clear concepts for an optimised usage of vitamin D to improve the immune system and prevent infectious diseases in dairy cows.

Do Vitamin D receptor gene polymorphisms affect bone mass density in men?: A meta-analysis of observational studies

The signs of aging in humans can often be detected through a decrease in bone mass density (BMD). The decrease in BMD as a risk of osteoporosis is often only seen in women, but not in men, even though men also have a risk of osteoporosis which can affect their well-being. We conducted study searches through databases such as PubMed, EBSCO, ProQuest, Willey Online, Science Direct, and SAGE. We performed analysis on four types of Vitamin D receptor polymorphisms: BsmI, ApaI, FokI, and TaqI from 14 potential studies involving men. We found that several genetic analysis models of BsmI and FokI significantly affected BMD in men: BB vs bb in whole body BMD (SMD = 0.43, 95% CI = [0.12-0.75], p = 0.0008, BB vs Bb in whole body BMD (SMD = -1.38, 95% CI = [-1.87 to 0.88], p < 0.00001), and FF+Ff vs ff spine BMD (SMD = 0.59, 95% CI = 0.13-1.05], p = 0.001), even after adjusting for comorbidities as confounding variables. The present meta-analysis showed that BsmI and FokI polymorphisms of the VDR gene were correlated with decreased BMD in men which may contribute to the aging process and well-being.

Vitamin D, Vitamin D Receptor (VDR) Gene Polymorphisms (ApaI and FokI), and Bone Mineral Density in Patients With Inflammatory Bowel Disease

In the etiology of inflammatory bowel disease (IBD) and osteoporosis, the connecting element is the involvement of environmental and genetic factors. Vitamin D receptor (VDR) gene polymorphisms may be associated with the pathogenesis of IBD and bone mineral density (BMD). The study aimed to analyze the relationship between ApaI and FokI polymorphisms of the VDR gene, serum vitamin D concentration, and BMD in patients with IBD. The studied group consisted of 172 patients (85 with Crohn's disease [CD], 87 with ulcerative colitis [UC], and 39 healthy subjects - control group [CG]) were examined. Lumbar spine densitometry (L1-L4) and the femoral neck (FN) measurements were performed using dual-energy X-ray absorptiometry (DXA). Serum concentrations of 25-hydroxyvitamin D were determined using electrochemiluminescence binding assay (ECLIA). Polymorphisms were determined with polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). . We found no statistically significant differences in vitamin D concentration between the 3 studied groups. CD patients who were FF homozygotes had significantly lower FN BMD than FF homozygous from CG (p-value < 0.05). CD patients who were Aa heterozygotes had significantly lower lumbar spine (L2-L4) BMD than Aa heterozygotes from CG (p-value < 0.05). Among patients with the same polymorphic variants, but belonging to different studied groups, statistically significant differences in bone mineral density in the lumbar spine and the closer end of the femoral neck were observed. We consider that it is the disease entity, not the polymorphism variant, may have a decisive impact on BMD.

Are vitamin D and vitamin D receptor levels different in children with developmental dysplasia of the hip?

INTRODUCTION

Developmental dysplasia of the hip (DDH) is a common disorder and associated with significant morbidity of the hip joint. Several risk factors have been identified for DDH. The aim of this study is to investigate whether vitamin D and vitamin D receptor (VDR) levels differ in children with DDH and whether they have an effect on DDH development.

MATERIALS AND METHODS

A total of 40 (17 males, 23 females; 9 right hips, 16 left hips, 15 bilateral hips) children who were treated for developmental dysplasia and 40 (23 males, 17 females) healthy children without any musculoskeletal system and metabolic disorders were included in this study between January and June 2019. Blood samples from the DDH and control groups of children were collected to measure the serum levels of vitamin D, VDR, calcium (Ca), phosphorus (P), and alkaline phosphatase (ALP). The levels of Ca, P, and ALP were analyzed using the automated standard spectrophotometric laboratory method. The levels of vitamin D and VDR in the samples were analyzed using enzyme-linked immunoassay.

RESULTS

There were no significant differences in the serum levels of Ca, P, ALP, and vitamin D between the DDH and healthy groups (Ca 9.96 ± 0.47 vs. 9.92 ± 0.48 mg/dL, respectively, p = 0.721; P 5.3 ± 0.94 vs. 4.82 ± 0.88 mg/dL, respectively, p = 0.23; ALP 252.22 ± 170.15 vs. 245.3 ± 130.93 U/L, respectively, p = 0.839). However, serum VDR levels were significantly lower in children in the DDH group (5.77 ± 3.51 ng/mL) than in the healthy control group (9.25 ± 6.43 ng/mL) (p = 0.004).

CONCLUSIONS

In conclusion, we believe that low VDR levels can affect DDH regardless of the serum levels of Ca, P, ALP, and vitamin D. More comprehensive studies involving parents are needed to understand whether VDR levels mediate genetic transmission in DDH or not.

The Influence of Vitamin D Receptor Gene Polymorphisms in Spondyloarthritis

Spondyloarthritis (SpA) is an inflammatory rheumatic disease related to low bone mineral density. Because vitamin D plays an important role in bone metabolism and immune system modulation, the aim of this study was to evaluate the influence of polymorphisms in vitamin D receptor genes (VDR) in the development of SpA. In this case-control study, a total of 244 patients with SpA and 197 individuals with no SpA were included. Among the patients, 174 had ankylosing spondylitis (AS) and 66 had psoriatic arthritis (PsA). Genotyping of FokI (rs2228570 C > T), BsmI (rs1544410 C > T), ApaI (rs7975232 A > C), and TaqI (rs731236 T > C) was performed using PCR-RFLP, while genotyping of HLA-B∗27 was performed using PCR-SSP. Serum levels for hydroxy (OH) vitamin D and the clinical activity index of the disease (BASDAI) were also evaluated. SNPStats and OpenEpi software were used for statistical analysis. The ApaI a allele and ApaI a/a genotype were less frequent in PsA compared with controls. The ApaI a/a genotype was associated with a protecting factor for PsA in females, and ApaI A/a was associated with a protecting factor for the disease in HLA-B∗27 positive patients. Notwithstanding, the ApaI a/a genotype was a risk factor for SpA and AS in males. The FokI f/f genotype was associated with a better clinical activity in PsA. When considering the covariates, vitamin D sufficiency, and gender, the FokI F/F genotype was associated with a risk factor in males with SpA and AS compared with females with this same genotype. In conclusion, the ApaI rs7975232 polymorphism was associated with PsA, and the FokI rs2228570 polymorphism was associated with better clinical PsA activity. ApaI and FokI were associated with SpA and AS when considering gender and vitamin D sufficiency.

Single nucleotide vitamin D receptor polymorphisms (FokI, BsmI, ApaI, and TaqI) in the pathogenesis of prematurity complications

The vitamin D receptor (VDR), coded by the VDR gene, plays a pivotal role in executing cellular functions when bound by the active form of vitamin D. Gene polymorphisms in this receptor have been increasingly associated with a heightened state of vulnerability to certain diseases. However, limited data is available concerning the role of VDR gene polymorphisms in preterm infant complications. In 114 premature infants (< 32 weeks gestation) we analyze four single nucleotide VDR polymorphisms (rs2228570 (FokI), rs1544410 (BsmI), rs797532 (ApaI), rs731236 (TaqI)) for their association with respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC) and retinopathy of prematurity (ROP). The results show that BPD was almost four times more likely in infants with the genotype CC of ApaI (rs7975232) (OR 3.845; p = 0.038). While both BPD and NEC were 2.1 times more likely to occur in preterm infants with the allele C of ApaI (rs7975232) (respectively: OR 2.111 and OR 2.129, p < 0.05). The ApaI VDR polymorphism appears to influence incidence of BPD and NEC in preterm infants. Considering VDR polymorphisms in future genetic investigations, in preterm complications, may prove clinically relevant.

Vitamin D receptor (VDR) gene FokI, BsmI, ApaI, and TaqI polymorphisms and osteoporosis risk: a meta-analysis

Background

Osteoporosis is a disease of the bones in which the density of the bones decreases. The prevalence of this disease greatly varies in different populations of the world. Numerous studies have been investigated VDR gene polymorphisms as osteoporosis risk in different ethnic groups. In present meta-analysis, the aim is to find out the role of VDR gene polymorphisms (FokI, BsmI, ApaI, and TaqI) in osteoporosis risk.

Methods

Suitable case-control studies for present meta-analysis were retrieved from four electronic databases. Open Meta-Analyst program was used for statistical analyses.

Results

Studies investigated BsmI (65 studies; 6880 cases/8049 controls), ApaI (31 studies; 3763 cases/3934 controls), FokI (18 studies; 1895 cases/1722 controls), and TaqI (26 studies; 2458 cases/2895 controls) polymorphisms that were included in the present meta-analysis. A significant association was found between the dominant model of FokI (ORff + Ffvs.FF = 1.19, 95% CI = 1.04–1.36, p = 0.01, I2 = 39.36%) in the overall analysis and recessive model of the Caucasian population of TaqI polymorphism (ORTT + Ttvs.tt = 1.35, 95% CI = 1.11–1.63, p = 0.002, I2 = 50.07%) with osteoporosis. On the other hand, no such effect is found in any other genetic models and in any other gene polymorphisms of the overall analyses or sub-group analyses.

Conclusion

In conclusion, the authors found that the dominant model of FokI in the overall analysis and recessive model of TaqI in the Caucasian population are significantly associated with the development of osteoporosis.

Gut microbiota alterations associated with reduced bone mineral density in older adults

Objective

To investigate compositional differences in the gut microbiota associated with bone homeostasis and fractures in a cohort of older adults.

Methods

Faecal microbiota profiles were determined from 181 individuals with osteopenia (n = 61) or osteoporosis (n = 60), and an age- and gender-matched group with normal BMD (n = 60). Analysis of the 16S (V3-V4 region) amplicon dataset classified to the genus level was used to identify significantly differentially abundant taxa. Adjustments were made for potential confounding variables identified from the literature using several statistical models.

Results

We identified six genera that were significantly altered in abundance in the osteoporosis or osteopenic groups compared with age- and gender-matched controls. A detailed study of microbiota associations with meta-data variables that included BMI, health status, diet and medication revealed that these meta-data explained 15–17% of the variance within the microbiota dataset. BMD measurements were significantly associated with alterations in the microbiota. After controlling for known biological confounders, five of the six taxa remained significant. Overall microbiota alpha diversity did not correlate to BMD in this study.

Conclusion

Reduced BMD in osteopenia and osteoporosis is associated with an altered microbiota. These alterations may be useful as biomarkers or therapeutic targets in individuals at high risk of reductions in BMD. These observations will lead to a better understanding of the relationship between the microbiota and bone homeostasis.

Association of vitamin D receptor gene polymorphisms with disc degeneration

PURPOSE

Numerous candidate genes and single-nucleotide polymorphisms (SNPs) have been identified in the background of lumbar disc degeneration (LDD). However, in most of these underpowered studies, definitions of LDD are inconsistent; moreover, many of the findings have not been replicated and are contradictory. Our aim was to characterize LDD by well-defined phenotypes and possible endophenotypes and analyse the association between these and candidate vitamin D receptor (VDR) gene polymorphisms on a large (N = 1426) dataset.

METHODS

Seven candidate VDR SNPs were genotyped. Individual association, haplotype and gene-gene interaction analyses were performed. All degenerative endophenotypes were significantly associated with one or more candidate VDR gene variants.

RESULTS

Haplotype analyses confirmed the association between the 3'-end VDR variants (BsmI, ApaI, TaqI) and Modic changes as well as the relationship of 5'-end variants (Cdx2, A1012G) with endplate defects. We also found significant interactions between the 3'- and 5'-end regulatory regions and endplate defects. Based on our results, VDR and its gene variants are highly associated with specific degenerative LDD endophenotypes.

CONCLUSION

Understanding relationships between phenotype and gene variants is crucial for describing the pathways leading to the multifactorial, polygenic degeneration process and LDD-related conditions. These slides can be retrieved under Electronic Supplementary Material.

Comorbidities in multiple sclerosis-a plea for interdisciplinary collaboration to improve the quality of life of MS patients

The negative influence of comorbidities on the quality of life of people with multiple sclerosis is evident and the problem is increasingly acknowledged by numerous international studies in long-term care. One therapeutic option would be an add-on therapy with vitamin D (VD), with the aim of achieving a therapeutically effective dose. The individually required VD dose must be tested, since the response to a certain dose is subject to variations between individuals. A possible toxicity with increased 1.25(OH)D3 (active VD metabolite) is largely prevented by increased activity of 24-hydroxylase (CYP24A1). Monitoring of serum VD levels as well as serum calcium and phosphate levels (optional Ca excretion in 24-hour urine, Ca creatinine ratio in urine) provides safety and is necessary because possible mutations on the (catabolic) CYP24A1 gene can lead to a partial or total loss of 24-hydroxylase activity and provoke hypercalcemia/hyperphosphatemia. The main therapeutic objective is to maintain functional and social independence by using drugs with a high safety profile. The prevention and optimal management of comorbidities can influence the quality of life of patients with MS (PwMS) when included in patient care. Adequate measures can reduce the burden of MS only if the risk of comorbidity is reduced through targeted monitoring, early detection and diagnosis. Such a strategy will contribute to influencing the premature mortality of patients with MS. If VD is recognized as a "multipurpose steroid hormone", it could also be used to maintain cognitive function and prevent premature possible dementia, especially as there is evidence that VD deficiency correlates with brain atrophy (hippocampus). At present, MS therapy is still a balancing act between therapeutically efficient action and the management of unexpected side effects, with VD add-on therapy being almost unproblematic and most likely to be accepted by PwMS.

Association of vitamin D receptor ApaI gene polymorphism with osteoporosis susceptibility in postmenopausal Han Chinese women in Xinjiang

Osteoporosis is a polygenic disorder and has been demonstrated to be associated with ~30 candidate genes, the majority of which have also been implicated in the regulation of bone mineral density (BMD). Vitamin D receptor (VDR) is the candidate gene that has been most extensively studied. Certain studies have reported that the VDR single nucleotide polymorphism ApaI is associated with the risk of osteoporosis in Caucasian and African women. However, this association has not yet been studied in postmenopausal Han Chinese women in the Xinjiang area. In the present study, ApaI polymorphisms of VDR were defined by polymerase chain reaction-restriction fragment length polymorphism, in order to analyze the distribution of ApaI polymorphisms in postmenopausal Han Chinese women from Xinjiang. BMD was measured by dual energy X-ray absorptiometry at the lumbar spine (L2-4), Ward's triangle, great trochanter and femoral shaft. A total of 336 women were included in this study. The genotype distribution of ApaI was consistent with the Hardy-Weinberg equilibrium (all P>0.05). There were no significant differences in ApaI genotype frequencies between the 90 cases in the osteoporosis group and 246 cases in the non-osteoporosis group (P=0.946). Meanwhile, it was identified that BMD values of the tested locations were negatively correlated with age (P<0.05) and positively correlated with body mass index (BMI; P<0.05). On further attribution risk analysis, BMD was identified as a risk factor [odds ratio (OR): 0.464, 95% confidence interval (CI): 0.372-0.580, P=0.001] and BMI a protective factor (OR: 1.502, 95% CI: 1.008-2.240, P=0.032) in osteoporosis. When BMD was adjusted for confounding factors including age and BMI, it was observed that the ApaI polymorphism was not associated with BMD at the sites tested (P>0.05). In conclusion, the present study identified no significant association of the common VDR polymorphism ApaI with BMD at several skeletal sites in postmenopausal Han Chinese women in the Xinjiang area. Age was negatively correlated with BMD at different sites and identified as a risk factor; while BMI was positively correlated with BMD and identified as a protective factor.

Association analysis between four vitamin D receptor gene polymorphisms and developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) is a congenital condition characterized by abnormality in acetabulum size and/or shape. The incidence rate of DDH differs between different populations with risk factors including positive family history, breech presentation, sex, firstborn status, side of the hip, mode of delivery and oligohydramnios. It is recognized that DDH has a genetic component that exhibit autosomal dominant patterns. Many candidate genes have been studied and found to be associated with the disease; most of them are normally involved in cartilage development and joint metabolism. In this study, the association of four single-nucleotide polymorphisms (SNPs) (rs731236, rs1544410, rs7975232 and rs2228570) in the vitamin D receptor (VDR) gene was studied by a case-control analysis. The study sample involves 50 cases with confirmed DDH presentation and 50 nonDDH controls. SNPs were genotyped using conventional polymerase chain reaction (PCR) and restriction fragment-length polymorphism (RFLP) techniques. Genotype and allele frequencies were analysed using SPSS software. No significant associations were found between the VDR polymorphisms analysed and DDH. Further work need to be performed using genomewide analysis to elucidate the genetic basis of DDH.

Association between IGF-1 polymorphisms and risk of osteoporosis in Chinese population: a meta-analysis

Background

Several studies looking into the association between insulin-like growth factor-1 (IGF-1) gene polymorphisms and osteoporosis predisposition have been conducted among Chinese population with conflicting outcomes. The present systematic review and meta-analysis was performed to appraise and synthesize the existing evidence, so as to provide a more precise and reliable association between polymorphisms in IGF-1 gene and osteoporosis.

Methods

Five electronic databases including PubMed, EMBASE, ISI Web of Science, CNKI and Wanfang were systematically searched for potential studies. Summary odds ratio (OR) and corresponding 95% confidence interval (95% CI) were calculated to evaluate the association. The best-matching genetic model of inheritance was determined using a genetic-model free approach.

Results

Six case-control studies comprising 2068 osteoporosis patients and 2071 healthy controls were obtained for the meta-analysis. Dominant model was confirmed to be the best-matching genetic model (TT + TC versus CC). The overall data suggested that rs35767 polymorphism was significantly associated with osteoporosis vulnerability (OR 1.21, 95% CI 1.07, 1.37; P = 0.002). When stratifying the participants and performing subgroup-analysis according to source of patients, the result suggested that rs35767 was significantly correlated to osteoporosis in post-menopausal women subgroup (OR 1.29, 95% CI 1.08, 1.54; P = 0.005), but the correlation was not established in the subgroup of both gender (OR 1.14, 95% CI 0.96, 1.35; P = 0.12).

Conclusion

Taken together, the findings of our current study suggested a significant association between rs35767 polymorphism and risk of osteoporosis in Chinese post-menopausal women.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2066-y) contains supplementary material, which is available to authorized users.

Effects of genetic variants on serum parathyroid hormone in hyperparathyroidism and end-stage renal disease patients: A systematic review and meta-analysis

BACKGROUND

Parathyroid hormone (PTH) is one of the principal regulators of calcium homeostasis, crucial for normal functioning of the kidneys, bones, heart, and nervous system. Different pathologic conditions can affect serum PTH level resulting in hyperparathyroidism or hypoparathyroidism. Our study assessed the association of previously reported polymorphisms with the level of PTH (expressed in pg/mL) among individuals with different pathologic conditions affecting PTH level.

METHODS

We searched Web of Science, MEDLINE, and Scopus to identify relevant articles published up to July 2017. The search yielded 6967 publications of which 44 fulfilled the inclusion criteria. We conducted meta-analyses for calcium-sensing receptor gene (CaSR) rs1801725 polymorphism in patients with primary hyperparathyroidism and vitamin D receptor gene (VDR) rs1544410 polymorphism in patients with end-stage renal disease (ESRD).

RESULTS

None of the polymorphisms were significantly associated with PTH levels in the overall population. In subgroup analysis by ethnicity for VDR rs1544410 gene polymorphism, we found significant differences under dominant model (SMD: -0.18 [-0.32, -0.05], P < .01) and AA versus GG comparison (SMD: -0.29 [-0.52, -0.06], P < .01) in Asian patients with ESRD, while nominally significant results (P < .05) were observed for AG versus GG and AA versus GG comparisons in European individuals with ESRD.

CONCLUSION

Scientific evidence of genetic association of serum PTH level among individuals with different pathologic conditions remains deficient and published results provide weak evidence. Further well-conducted studies on larger sample sets designed according to evidence-based principles are warranted to assure clinically applicable findings.

Lack of association between vitamin D receptor genes BsmI as well as ApaI polymorphisms and osteoporosis risk: A pooled analysis on Chinese individuals

BACKGROUND

As for the association between vitamin D receptor (VDR) gene polymorphisms and osteoporosis, the current results have yielded conflicts. Therefore, we performed a pooled analysis based on Chinese individuals to provide comprehensive data on the association between VDR BsmI, ApaI, Tru9I polymorphisms and osteoporosis risk.

METHODS

Studies were identified using PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure and Chinese Biology Medicine databases through to January 2017. Studies were screened according to the predefined inclusion and exclusion criteria. The association between VDR BsmI, ApaI, Tru9I polymorphisms and osteoporosis was evaluated by calculating pooled odds ratios (ORs) based on the individual ORs. The significance of the pooled OR was evaluated by a Z-test. All statistical analyses were conducted using Stata 12.0 software (StataCorp, College Station, TX, USA).

RESULTS

A total of 13 studies with 1141 osteoporosis cases and 1263 controls were included in this meta-analysis. It revealed that VDR Tru9I polymorphism was associated with an increased risk of osteoporosis in a common model (OR = 2.67, CI 95% = 1.59-4.49). No significant association was observed between VDR BsmI, ApaI and osteoporosis.

CONCLUSION

In conclusion, this meta-analysis suggests that VDR Tru9I polymorphism may be associated with osteoporosis risk in Chinese individuals, while BsmI, ApaI polymorphisms might not be a risk factor for osteoporosis.

Association of vitamin D receptor BsmI rs1544410 and ApaI rs7975232 polymorphisms with susceptibility to adolescent idiopathic scoliosis: A systematic review and meta-analysis

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.

Association of insulin-like growth factor I gene polymorphisms with the risk of osteoporosis in a Chinese population

Osteoporosis is a systemic metabolic and serious skeletal disease commonly observed among the elderly. Insulin-like growth factors (IGFs) are critical regulators for bone cell function. We estimated the role of IGF-I rs35767, rs2288377 and rs5742612 polymorphisms in the susceptibility to osteoporosis in a population of China, and assessed gene-environment interactions. A total of 346 patients with osteoporosis and 346 controls were enrolled. Genotyping of IGF-I rs35767, rs2288377 and rs5742612 was amplified and performed with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The TA and AA genotypes displayed elevated risk of developing osteoporosis (TA vs TT: OR=1.54, 95% CI=1.11-2.15; AA vs TT: OR=3.65, 95% CI=2.09-6.37). Compared with TT individuals, individuals with the TA+AA genotype had a substantial increased susceptibility to osteoporosis (OR=1.80, 95% CI=1.31-2.46). In recessive model, the AA genotype of rs2288377 displayed 2.89 folds risk of osteoporosis (adjusted OR=2.89, 95% CI=1.70-4.89). A significant negative interaction was found between IGF-I rs2288377 and BMD levels for femoral neck (r=-0.14, P<0.001), total hip (r=-0.09, P<0.001) and trochanter (r=-0.13, P<0.001). In conclusion, we suggest that IGF-I rs2288377 polymorphism had a strong influence on osteoporosis susceptibility in this Chinese population.