Association between Vitamin D Receptor Gene Polymorphisms and Periodontal Bacteria: A Clinical Pilot Study

Pathways of the vitamin D receptor gene and dental caries: A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to investigate the influence of single nucleotide polymorphisms (SNPs) related to vitamin D receptor genes (VDR) on caries experience.

METHODS

The search included five databases, focusing exclusively on human studies. Meta-analyses were conducted for each SNP and polling data from various SNPs within the gene. A Funnel Plot and Egger's test were performed.

RESULTS

Fourteen studies were included in the systematic review and thirteen in the meta-analysis. Seven SNPs related to VDR were assessed, and most (57.1 %) were in exon regions. A total of 4944 participants were included. No individual SNP was found to be significantly associated with caries in any of the evaluated models (allelic, genotypic heterozygous, or homozygous) (p > 0.05). No difference was observed even when stratifying via subgroup analysis according to population (p > 0.05). In the gene-level analysis adjusted by linkage disequilibrium, the overall model showed an OR of 0.93 (95 %CI: 0.69-1.23) for the allelic analysis, 1.15 (95 %CI: 0.84-1.57) for the homozygous genotypic model, and 1.18 (95 %CI: 0.95-1.48) for the heterozygous genotypic model. When stratified by subgroups, the East Asian population was associated with an increased OR of 1.42 (95 %CI: 1.01-2.01) in the heterozygous genotypic model. Egger's test showed no significant publication bias for all models (p > 0.05).

CONCLUSIONS

The present findings showed that the SNPs in VDR are influenced by ethnic background and may play an important role in dental caries experience according to different ethnic groups. (CRD42020134424).

Vdr mediates Wnt signaling pathway to regulate odontoblasts differentiation during dentin apposition

Dentin, a complex, living, and porous mineral substance, is produced by the mineralization of predentin, which is secreted by odontoblasts. This substance is crucial for maintaining the health of teeth. However, the specific function of the vitamin D receptor (Vdr) in the mineralization of odontoblasts, dentin homeostasis, and its interaction with Wnt signaling pathway during dentin apposition is not well understood. In this study, we employed Vdr transgenic knockout mice to study the dental effects and observed enlarged pulp cavities, diminished dentin, and increased predentin thickness in Vdr-/- mice. We further reduced Vdr expression in odontoblasts and analyzed the changes in mineralization and Wnt signaling pathway. Our results showed decreased levels of mineralization and its markers Dspp, Alpl, Opn, Col-1, and Bsp in Vdr-knockdown odontoblasts. Additionally, the Wnt signaling pathway was downregulated, as indicated by lower levels of β-catenin, Lef1, and Axin2, and higher levels of Dkk1. We then attempted to rescue these effects by treating them with lithium chloride (LiCl) which activated the Wnt signaling pathway and appeared to restore the mineralization capacity of odontoblasts. Overall, our findings suggest that Vdr can mediate the Wnt signaling pathway to regulate odontoblasts differentiation during dentin apposition, presenting new potential approaches for improving dental health.

Vitamin D binding protein and receptor prevalence in a large population with periodontitis: single nucleotide polymorphism and transcriptomic profiling

BACKGROUND

There is an ongoing controversy regarding the expression of vitamin D receptor (VDR) and binding protein (VDBP) genes, as well as their polymorphisms, in periodontitis. We examined eight single nucleotide polymorphisms (SNPs) and performed a transcriptome-level bioinformatics analysis to clarify their relationship with periodontitis.

METHODS

To explore VDR and VDBP polymorphisms, 600 subjects were included, including 307 patients with chronic periodontitis (CP) and 293 healthy controls. Genomic DNA was extracted from peripheral venous blood collected from each subject. A MassARRAY system was used to detect SNPs, including rs1544410G/A (BsmI), rs2228570C/T (FokI), rs7975232G/T (ApaI), rs731236T/C (TaqI), rs739837G/T, rs9729G/T, and rs3847987C/A in the VDR gene, and rs7041A/C in the VDBP gene. Then, we analyzed transcriptome sequencing datas of gingival tissues from two single-cell transcriptome sequencing studies to identify differential expression profiles. The objective was to further explore the potential association between VDR gene and gingival tissues in individuals with CP.

RESULTS

The regression analysis model revealed a significant relationship between rs739837G/T (P = 0.04) and rs7041A/C (P = 0.03) polymorphisms and CP susceptibility. Subjects carrying the TT genotype of rs739837 showed a decreased risk of developing CP compared to those carrying the GG + GT genotype (OR = 0.53, 95% CI = 0.29-0.99). Individuals carrying the AC + CC genotype of rs7041 showed a reduced risk of developing CP compared to those with the AA genotype (OR = 0.70, 95% CI = 0.51-0.97). Furthermore, allele C of rs7041 was found to have a protective effect against periodontitis (P = 0.03, OR = 0.75, CI = 0.58-0.98). However, no association was found between CP susceptibility and six other 6 SNPs (rs1544410, rs2228570, rs7975232, rs9729, rs731236, and rs3847987). Differential levels of VDR transcription were observed in gingival tissues during CP.

CONCLUSIONS

VDR genetic variability and transcriptional expression are significant factors affecting susceptibility to CP. These findings suggested that rs739837 TT in VDR and rs7041 A/C in VDBP may be protective against periodontitis.

Genetic Testing as a Source of Information Driving Diagnosis and Therapeutic Plan in a Multidisciplinary Case

In many cases, the etiopathogenesis of oral cavity diseases depends on the presence of variants in some genes. Being able to identify these variants defines the possibilities and limits of therapies. This multidisciplinary case describes several pathologies of the oral cavity in a young patient affected by type 1 diabetes. The patient presented with an impacted palatal canine. Further investigation revealed cervical root resorption of the upper right central incisor. Genetic testing was performed for interleukin, VDR receptor genes, and the evaluation of periodontopathogenic bacteria. The mutational analysis carried out for the VDR polymorphisms and the IL1A, IL1B, IL6, and IL10 polymorphisms showed the presence of pathogenetic variants. The results for bacterial load showed the presence of periodontal pathogenes. The first intervention was the intentional replantation of the incisor. The second intervention was the orthodontic recovery of the impacted canine, using light forces and a hybrid anchorage with a miniscrew. At the end of orthodontic treatment, a crack was found in the upper left first premolar, which was extracted. Throughout treatment, non-invasive periodontal interventions were performed periodically to control periodontal inflammation. This case is an example of the integration of genetic analyses into the multidisciplinary diagnostic pathway.

Oral microbiota in human health and disease: A perspective

The evolution of medical knowledge about oral microbiota has increased awareness of its important role for the entire human body health. A wide range of microbial species colonizing the oral cavity interact both with each other and with their host through complex pathways. Usually, these interactions lead to a harmonious coexistence (i.e. eubiosis). However, several factors - including diet, poor oral hygiene, tobacco smoking, and certain medications, among others - can disrupt this weak homeostatic balance (i.e. dysbiosis) with potential implications on both oral (i.e. development of caries and periodontal disease) and systemic health. This article is thus aimed at providing an overview on the importance of oral microbiota in mediating several physiological and pathological conditions affecting human health. In this context, strategies based on oral hygiene and diet as well as the role of probiotics supplementation are discussed.

Metals Biotribology and Oral Microbiota Biocorrosion Mechanisms

During the last decades, metal-based biomaterials have been extensively explored to be used as biocompatible metals for biomedical applications, owing to their superior mechanical properties and corrosion resistance. Consequently, for long-term implanted medical devices, to assure the biomaterials' reliability, functionality, and biocompatibility, studying the various bio-tribological damage mechanisms to obtain the optimum properties is one of the most important goals. In this review, we consider the most important metal-based biomaterials such as stainless steel, alloys of titanium (Ti), cobalt-chromium (Co-Cr), and Nichel-Titatium (Ni-Ti), as well Magnesium (Mg) alloys and with Tantalum (Ta), emphasizing their characteristics, clinical applications, and deterioration over time. The influence of metal elements on biological safety, including significant effects of metal-based biomaterials in dentistry were discussed, considering the perspectives of surface, mechanical properties, corrosion behaviors, including interactions, bio-mechanisms with tissues, and oral environments. In addition, the role of the oral microbiota was explored due to its role in this erosion condition, in order to further understand the mechanism of metal-based biomaterials implanted on the microflora balance of aerobic and anaerobic bacteria in an oral environment.

Biomolecular Mechanisms of Autoimmune Diseases and Their Relationship with the Resident Microbiota: Friend or Foe?

The use of innovative approaches to elucidate the pathophysiological mechanisms of autoimmune diseases, as well as to further study of the factors which can have either a positive or negative effect on the course of the disease, is essential. In this line, the development of new molecular techniques and the creation of the Human Genome Program have allowed access to many more solutions to the difficulties that exist in the identification and characterization of the microbiome, as well as changes due to various factors. Such innovative technologies can rekindle older hypotheses, such as molecular mimicry, allowing us to move from hypothesis to theory and from correlation to causality, particularly regarding autoimmune diseases and dysbiosis of the microbiota. For example, Prevotella copri appears to have a strong association with rheumatoid arthritis; it is expected that this will be confirmed by several scientists, which, in turn, will make it possible to identify other mechanisms that may contribute to the pathophysiology of the disease. This article seeks to identify new clues regarding similar correlations between autoimmune activity and the human microbiota, particularly in relation to qualitative and quantitative microbial variations therein.