Associations between polymorphisms in VDR gene and the risk of osteoporosis: a meta-analysis

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.

Modulation of the vitamin D receptor by traditional Chinese medicines and bioactive compounds: potential therapeutic applications in VDR-dependent diseases

The Vitamin D receptor (VDR) is a crucial nuclear receptor that plays a vital role in various physiological functions. To a larger extent, the genomic effects of VDR maintain general wellbeing, and its modulation holds implications for multiple diseases. Current evidence regarding using vitamin D or its synthetic analogs to treat non-communicable diseases is insufficient, though observational studies suggest potential benefits. Traditional Chinese medicines (TCMs) and bioactive compounds derived from natural sources have garnered increasing attention. Interestingly, TCM formulae and TCM-derived bioactive compounds have shown promise in modulating VDR activities. This review explores the intriguing potential of TCM and bioactive compounds in modulating VDR activity. We first emphasize the latest information on the genetic expression, function, and structure of VDR, providing a comprehensive understanding of this crucial receptor. Following this, we review several TCM formulae and herbs known to influence VDR alongside the mechanisms underpinning their action. Similarly, we also discuss TCM-based bioactive compounds that target VDR, offering insights into their roles and modes of action.

Effects of Isoflavonoid and Vitamin D Synergism on Bone Mineral Density-A Systematic and Critical Review

Phytoestrogens are non-steroidal plant compounds, which bind to α and β estrogen receptors, thereby causing specific effects. The best-known group of phytoestrogens are flavonoids, including isoflavonoids-genistein and daidzein. They play a role in the metabolism of bone tissue, improving its density and preventing bone loss, which contributes to reducing the risk of fractures. Vitamin D is found in the form of cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2) and is traditionally recognized as a regulator of bone metabolism. The aim of this review was to evaluate the synergistic effect of isoflavonoids and vitamin D on bone mineral density (BMD). The MEDLINE (PubMed), Scopus and Cochrane databases were searched independently by two authors. The search strategy included controlled vocabulary and keywords. Reference publications did not provide consistent data regarding the synergistic effect of isoflavonoids on BMD. Some studies demonstrated a positive synergistic effect of these compounds, whereas in others, the authors did not observe any significant differences. Therefore, further research on the synergism of isoflavonoids and vitamin D may contribute to a significant progress in the prevention and treatment of osteoporosis.

VDR gene ApaI polymorphism and risk of postmenopausal osteoporosis: a meta-analysis from 22 studies

OBJECTIVE

The ApaI polymorphism (G > T, rs7975232) of the vitamin D receptor (VDR) gene in the risk of postmenopausal osteoporosis has been widely researched, and the results have yielded conflicts. Therefore, we performed an updated pooled analysis to comprehensively assess the association between VDR ApaI polymorphism and postmenopausal osteoporosis risk.

METHODS

We searched eligible studies about ApaI polymorphism and osteoporosis through the PubMed, Embase, CNKI and Wanfang databases; case-control studies containing available genotype frequencies of A/a were chosen. We used the odds ratio with 95% confidence interval to assess the strength of this association. Sensitivity analysis and publication bias assessment were performed. Trial sequential analysis (TSA) was performed to evaluate a sufficient sample.

RESULTS

Twenty-two studies assessed the relationship between ApaI polymorphism and the risk of osteoporosis in postmenopausal women. The comprehensive analyses showed no significant association for ApaI polymorphism with postmenopausal osteoporosis in the overall population, equally valid for Asian and Caucasian subgroups with any genetic model. TSA still indicated the results were robust.

CONCLUSION

The present meta-analysis suggests that the VDR ApaI genotype may not affect the risk of postmenopausal osteoporosis in Asians and Caucasians.

Modulation of the vitamin D/vitamin D receptor system in osteoporosis pathogenesis: insights and therapeutic approaches

Osteoporosis is a prevalent bone disorder characterized by low bone mineral density (BMD) and deteriorated bone microarchitecture, leading to an increased risk of fractures. Vitamin D (VD), an essential nutrient for skeletal health, plays a vital role in maintaining bone homeostasis. The biological effects of VD are primarily mediated through the vitamin D receptor (VDR), a nuclear receptor that regulates the transcription of target genes involved in calcium and phosphate metabolism, bone mineralization, and bone remodeling. In this review article, we conduct a thorough literature search of the PubMed and EMBASE databases, spanning from January 2000 to September 2023. Utilizing the keywords "vitamin D," "vitamin D receptor," "osteoporosis," and "therapy," we aim to provide an exhaustive overview of the role of the VD/VDR system in osteoporosis pathogenesis, highlighting the most recent findings in this field. We explore the molecular mechanisms underlying VDR's effects on bone cells, including osteoblasts and osteoclasts, and discuss the impact of VDR polymorphisms on BMD and fracture risk. Additionally, we examine the interplay between VDR and other factors, such as hormonal regulation, genetic variants, and epigenetic modifications, that contribute to osteoporosis susceptibility. The therapeutic implications of targeting the VDR pathway for osteoporosis management are also discussed. By bringing together these diverse aspects, this review enhances our understanding of the VD/VDR system's critical role in the pathogenesis of osteoporosis and highlights its significance as a potential therapeutic target.

A Mini Review on Osteoporosis: From Biology to Pharmacological Management of Bone Loss

Osteoporosis refers to excessive bone loss as reflected by the deterioration of bone mass and microarchitecture, which compromises bone strength. It is a complex multifactorial endocrine disease. Its pathogenesis relies on the presence of several endogenous and exogenous risk factors, which skew the physiological bone remodelling to a more catabolic process that results in net bone loss. This review aims to provide an overview of osteoporosis from its biology, epidemiology and clinical aspects (detection and pharmacological management). The review will serve as an updated reference for readers to understand the basics of osteoporosis and take action to prevent and manage this disease.

An association of VDR gene polymorphism in hypovitaminosis D mediated secondary hyperparathyroidism in adolescent girls; a tertiary hospital study in central India

Vitamin D is required to maintain normal serum calcium and phosphate levels that help normal bone mineralization, nerve conduction, muscle contraction, immune function, cell proliferation, and differentiation. Interventions including vitamin D supplementation may not improve vitamin D deficiency, as various complex genomic actions could contribute to vitamin D deficiency in the Indian population. Thus, we assessed hypovitaminosis D's relationship with vitamin D receptor (VDR) gene polymorphism and evaluated parathyroid hormone (PTH) levels in seemingly healthy adolescent school-going girls. We included 100 school-going girls (aged 12-17 years) studying in four schools of different socio-economic strata of Bhopal, India. The selected participants were divided into four groups based on the school in which they were studying. Blood samples were tested for serum calcium, phosphorus, PTH, ALP, vitamin D 25(OH) D, and albumin levels.VDR polymorphism was detected through the PCR-RFLP. Data were analyzed using the chi-square test, ANOVA, and linear regression. The difference in the age, calcium, ALP, and vitamin D values between the four groups were significant (P < 0.05), whereas high PTH levels (80%) were found. A higher prevalence of homozygous polymorphic allele demonstrates a molecular signature for severe secondary hyperparathyroidism. Hypovitaminosis D ranged from 84.9% to 100%, and a high prevalence of VDR polymorphism was observed. Attention must be paid to the health of this age group of school-going girls as hypovitaminosis D and associated VDR gene polymorphism could be the reason for secondary hyperparathyroidism (SHPT), showing changes in bone mineral density in these adolescent girls to ensure their future health.

Association Between the TaqI (rs731236 T>C) Gene Polymorphism and Dental Caries Risk: A Meta-analysis

Objective: This study investigated the association of the TaqI (rs731236 T>C) polymorphism in the VDR gene with dental caries.

Methods: A comprehensive literature search was performed in PubMed, Web of Science, Embase, SinoMed (the Chinese biomedical literature service system), and the Wiley Online Library. Overall comparisons and subgroup analyses based on ethnicity and the presence of dental caries in dentition were performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess associations between gene polymorphisms and the risk of dental caries.

Results: Seven articles were included in this meta-analysis. The pooled results revealed a significant association of the TaqI (rs731236 T>C) polymorphism with dental caries in the allele contrast model (C vs. T: OR = 1.24, 95% CI = 1.07–1.44, I² = 42%, p = 0.005) and in the recessive genetic model (CC vs. TT/CT: OR = 1.38, 95% CI = 1.03–1.84, I² = 0%, p = 0.03). A stratified analysis based on ethnicity revealed a significant association between the TaqI (rs731236 T>C) polymorphism and the risk of dental caries in Asians (C vs. T: OR = 1.28, 95% CI = 1.06–1.54, I² = 60%, p = 0.009). Subgroup analysis based on the presence of dental caries in dentition found a significant association of the TaqI (rs731236 T>C) polymorphism with permanent tooth caries in the allele contrast model (C vs. T: OR = 1.40, 95% CI = 1.11–1.77, I² = 76%, p = 0.005) and the recessive genetic model (CC vs. TT/CT: OR = 1.44, 95% CI = 1.03–2.00, I² = 0%, p = 0.03).

Conclusion: The results of this meta-analysis suggest that the C allele and CC genotype of the TaqI (rs731236 T>C) polymorphism in the VDR gene are associated with an increased risk of dental caries.