Association between vitamin D receptor gene haplotypes and chronic periodontitis among Japanese men

The relationship between vitamin D receptor gene polymorphisms and periodontitis in turkish individuals with type 2 diabetes mellitus

Background and Aim

Vitamin D receptor (VDR) gene polymorphisms have been implicated in the pathogenesis of many diseases, such as periodontitis and diabetes mellitus (DM). The present study aimed to evaluate the distributions of VDR polymorphisms in diabetic individuals with healthy periodontium (DMH), diabetic individuals with periodontitis (DMP), nondiabetic individuals with healthy periodontium (H), and nondiabetic individuals with periodontitis (P).

Material and Methods

A total of 200 individuals (DMH = 40, DMP = 60, H = 40, and P = 60) were recruited. All clinical periodontal parameters, demographical, and biochemical variables were recorded. Blood samples were collected, and genomic DNA was isolated by Purelink® Genomic DNA Mini Kit. Genotyping of VDR polymorphisms ApaI, BsmI, FokI, and TaqI were determined by real-time polymerase chain reaction (PCR) using allele-specific probes.

Results

The distribution of the BsmI variant showed differences between DMH and H groups (P = 0.034). In addition, carrying the GG genotype (OR = 0.317; 95% CI = 0.126-0.797; P = 0.013) and the G allele (OR = 2.373; 95% CI = 1.203-4.681; P = 0.012) increased the risk of type 2 DM. Moreover, it was determined that the frequency of CC genotype of FokI variant was higher in DMP compared to DMH (P = 0.046). It was determined that having the CC genotype (OR = 2.706; 95% CI = 1.185-6.176; P = 0.017) and the C allele (OR = 1.917; 95% CI = 0.995-3.694; P = 0.049) increased the risk of periodontitis among diabetic individuals. No differences were detected among groups in the genotype and allele distributions of ApaI and TaqI variants (P > 0.05).

Conclusions

The present study showed that the BsmI variant was a risk factor for DM among periodontally healthy individuals and the FokI variant for periodontitis among diabetic individuals.

Profile of vitamin D receptor gene polymorphism TaqI in patients with periodontitis

The present study aimed to assess the incidence of the vitamin D receptor (VDR) gene polymorphism TaqI in patients with periodontitis, and the potential association of this polymorphism with the severity of the disease. This was a case-controlled study, which included 162 adults divided into two groups as follows: Case group (81 patients diagnosed with periodontitis) and control group (81 patients without periodontitis). Venous blood was obtained from each sample from which DNA was extracted. The gene polymorphism was determined using restricted fragment length polymorphism-PCR and DNA sequencing to identify endonuclease restrictions in exon 9 (TaqI). The data were analyzed using an independent samples t-test. VDR gene polymorphisms were detected in periodontitis cases with TT (86.4%), Tt (12.4%) and tt (1.2%) genotypes. DNA sequencing confirmed a change in the sequence of the VDR gene nucleotides in patients with periodontitis. The data indicated that the severity of periodontal tissue damage may be influenced by changes in the nucleotide sequence.

Bone-related polymorphisms and dental status in older men and women. Results of the longitudinal Pro.V.A. study

Background/purpose

Genetics plays a role in the susceptibility to periodontitis and tooth loss. Several studies examined the involvement of polymorphisms in candidate genes. We hypothesize that bone metabolism-related polymorphisms could be associated with the number of remaining teeth.

Materials and methods

Participants in the Pro.V.A. longitudinal Study: 3099 Italians (aged 65+ at baseline), 2196 at follow-up 1 (5yrs), 1641 at follow-up 2 (7yrs) underwent detailed interview and clinical-instrumental examination. Subjects, grouped by remaining teeth number (0, 1–7, 8–19, 20+), were genotyped for six different bone-related polymorphisms: collagen type Iα1 (COL1A1, Sp1, Ss alleles, n = 1068), vitamin D receptor (VDR, Fok I, Ff alleles, n = 300), calcitonin receptor (CALCR, Alu I, CT alleles, n = 1430), estrogen receptor alpha (ESR1, Pvu II and Xba I, Pp and Xx alleles, n = 1335 and n = 1324).

Results

COL1A1 associated with dental status: ss carriers had reduced incident tooth loss (p < 0.05). The low frequency of this genotype, 3.6% in the whole population, didn't grant sufficient statistical power to other findings, such as the lower prevalence of edentulism, consistent throughout the study. In men, CC genotype of CALCR was associated with higher tooth loss between follow ups (p < 0.05). Biochemical markers of inflammation didn't differ by genotype. Confounders such as diabetes, neoplasms, and smoking hampered the detrimental effect of S allele in the logistic regression analysis (OR = 0.67, 95% CI 0.4–1.0, p = 0.06).

Conclusion

The present study, demonstrating an association between tooth loss and COL1A1 and -in men- CALCR, contributes to the identification of genes involved in tooth loss and, possibly, susceptibility to periodontitis.

Association between Vitamin D Receptor Polymorphisms (BsmI and FokI) and Glycemic Control among Patients with Type 2 Diabetes

(1) Background: Several studies have suggested that the vitamin D receptor (VDR) gene plays a role in type 2 diabetes mellitus (T2DM) susceptibility. Nonetheless, the association between T2DM and VDR polymorphisms remains inconclusive. We determined the genotype of VDR rs1544410 (BsmI) and rs2228570 (FokI) polymorphisms among Malaysian patients with T2DM and their association with glycemic control factors (vitamin D levels, calcium, magnesium, and phosphate). (2) Methods: A total of 189 participants comprising 126 patients with T2DM (63 with good glycemic control and 63 with poor glycemic control) and 63 healthy controls were enrolled in this case-control study. All biochemical assays were measured using spectrophotometric analysis. VDR gene FokI and BsmI polymorphisms were analyzed using polymerase chain reaction and endonuclease digestion. (3) Results: Our findings revealed no significant differences in VDR FokI and BsmI genotypes between participants with T2DM and healthy controls. Moreover, no significant association was observed between both single nucleotide polymorphisms and glycemic control factors. Participants with poor glycemic control had significantly lower serum magnesium levels and significantly higher HOMA-IR compared to the other groups. (4) Conclusions: The present study revealed that VDR gene BsmI and FokI polymorphisms were not significantly associated with T2DM.

Vitamin D receptor FokI and BglI genetic polymorphisms, dental caries, and gingivitis

BACKGROUND & AIM

To investigate the association between the genetic polymorphisms FokI (rs2228570) and BglI (rs739837) in vitamin D receptor (VDR) with dental caries and gingivitis susceptibility.

DESIGN

This study included 353 Brazilian children (8 to 11 years old). Dental caries was assessed using ICDAS (International System for Detection and Assessment of Carious Lesions) and gingival bleeding using Community Periodontal Index (CPI). The presence of visible biofilm was also evaluated. DNA was extracted from saliva, and real-time PCR was used to evaluate genetic polymorphisms in VDR: rs2228570 (FokI, A>G/Met>Thr) and rs739837 (BglI, G>T). Dental caries was evaluated as a continuous data (mean and standard deviation-SD) and was also categorized (ICDAS₀ versus ICDAS_1-6 or ICDAS_1-2 versus ICDAS_3-6). Gingivitis was categorized in with and without. One-way ANOVA was used for comparisons of caries among genotypes. Chi-square test, logistic regression, and haplotype analysis were performed (P < .05).

RESULTS

Biofilm was associated with dental caries susceptibility and gingivitis (P < .05). The mean distribution of the caries lesions and cavitated caries lesions among FokI and BgII genotypes were not statistically significant (P > .05). Genotype distributions among caries groups (in the two different cut-offs) and among gingivitis and non-gingivitis groups were not statistically significant (P > .05).

CONCLUSION

The polymorphisms FokI and BglI in VDR were not associated with dental caries or gingivitis.

Influence of inflammasome NLRP3, and IL1B and IL2 gene polymorphisms in periodontitis susceptibility

The pathogenesis of periodontitis (PD) involves several molecules of the immune system that interact in a network to eliminate the periodontopathogens, yet, they contribute to periodontal tissue destruction. The different mechanisms that lead to periodontal tissue damage are not clear. Despite this, immune response genes have been related to the development of PD previously, such as those involved in inflammasomes which are multiprotein complexes and cytokines including Interleukin-1. The aim of the study was to evaluate the polymorphisms in NLRP3 inflammasome, cytokine and receptor of cytokines genes in the development of periodontitis. This case-control study was conducted in 186 patients with PD (stage II and III and grade B) and 208 controls (localized gingivitis and periodontally healthy individuals). Genotyping was performed using PCR-RFLP for the SNP rs4612666 in NLRP3 and using PCR-SSP for IL1A, IL1B, IL1R, IL1RN, IL4RA, INFG, TGFB1, TNF, IL2, IL4, IL6, and IL10. Cytokine serum levels were measured using Luminex technology. SNPStats and OpenEpi software were used to perform statistical analysis. The higher frequencies of NLRP3 T/C and IL1B -511 T/T genotypes and IL2 (+166, -330) GT haplotype were observed in patients with PD compared to controls. The SNPs in NLRP3, IL1R +1970, IL6–174, TNF -308, IL2 +166 and -330, TGFB1 +869 and +915, IL4RA +1902, IL4–1098 and -590 were associated to PD in men. In conclusion, polymorphisms in NLRP3, IL1B and IL2 genes were associated to PD susceptibility. Men carrying the NLRP3, IL1R, IL6, TNF, IL2, TGFB1, IL4RA and IL4 polymorphisms had greater susceptibility than women for developing PD.

Genetic influence of vitamin D receptor gene polymorphisms on osteoporosis risk

OBJECTIVE

Osteoporosis is the most common type of bone disorder characterized by low bone mineral density (BMD). It is a multifactorial disease and caused by the interaction of environmental and genetic factors. It has been reported that mutations in the vitamin D receptor (VDR) gene highly affect the metabolism of minerals, which reduces bone density. Therefore, this study aimed to determine the association of VDR gene polymorphisms TaqI (rs731236) and ApaI (rs7975232) with osteoporosis risk in the Saudi population.

METHODS

This case-control study involved 73 individuals with osteoporosis and 73 healthy controls in Jeddah, KSA. DNA extracted from peripheral blood was used to determine the genotypes and allele frequencies of VDR variants by polymerase chain reaction-restriction fragment length polymorphisms. Osteoporosis was confirmed by measuring BMD using dual-energy X-ray absorptiometry. The results were interpreted using the Hardy-Weinberg equilibrium assumption with P < 0.05 considered as significant.

RESULTS

A significant increase in the genotype frequencies of the ApaI (Aa) and (aa) was observed among osteoporotic patients compared to controls (P = 0.002 and P < 0.0001, respectively). Only the homozygous (tt) genotype of TaqI was significantly higher in those with osteoporosis than in the controls (P = 0.001). The minor "a" allele of ApaI and the "t" allele of TaqI were significantly more common in the patients as compared to controls (P < 0.0001 and P = 0.01, respectively).

CONCLUSION

VDR polymorphisms ApaI and TaqI were found to be significantly determinant risk factors for osteoporosis progression in the Saudi population.

Correlation of vitamin D receptor gene (ApaI) polymorphism with periodontitis: A meta-analysis of Chinese population

Many studies have tried to elucidate the connection between vitamin D receptor (VDR) gene (ApaI) polymorphism and periodontitis; however, so far there is no consensus. To further assess the impact of ApaI polymorphism on periodontitis risk, we have conducted a meta-analysis of Chinese population. Relevant literatures were searched according to PubMed and Chinese database in January 2019. The strength of correlation was evaluated by combining odds ratio (ORs) and 95% confidence interval (CIs). Six case-control studies were identified with inclusion criteria, including 734 cases of periodontitis and 687 controls. Based on the overall analysis, the VDR ApaI polymorphism was not due to the risk of periodontitis in all models. Subgroup analysis showed that the risk of periodontitis in North China was significantly reduced. To sum up, the study shows that VDR-ApaI polymorphism may be connected with a lower risk of periodontitis in northern China. It is suggested that inferential studies should be conducted in other ethnic groups.

Immunomodulatory factors gene polymorphisms in chronic periodontitis: an overview

BACKGROUND

Chronic periodontitis (CP), defines as destruction of the supporting tissues of the teeth and resorption of the alveolar bone. It is widespread in human populations and represent an important problem for public health. CP results from inflammatory mechanisms created by the interaction between environmental and host genetic factors that confer the individual susceptibility to the disease.

AIM

The aim of the current study was to explore and summarize some functional biomarkers that are associated with CP susceptibility.

METHODS

CP is considered to be a multifactorial disease. The pathogenesis of multifactorial diseases is characterized by various biological pathways. The studies revealed that polymorphisms were associated with susceptibility to periodontal diseases. In other word, genetic variations can change the development of CP. However, there are some conflicting results, because there are different variations in frequency of some alleles in any populations. Therefore, we conducted the current review to completely understanding the special biomarkers for CP.

RESULTS

There is some evidence that SNPs in the IL-1α, IL-1β, IL1RN, IL-6, IL-10, TNF-α, TGF-β1, IFN-γ and VDR may be associated with CP susceptibility.

CONCLUSION

In conclusion, numerous studies have reported the host genetic factors associated with CP susceptibility and related traits. Therefore, it is prevail to study the multiple SNPs and their effects to find the useful diagnosis methods. The current study will investigate the relationship between polymorphisms in cytokine genes and the susceptibility to the chronic periodontitis.

Polymorphisms of the vitamin D receptor gene (FOKI, CDX2, and GATA) and susceptibility to chronic periodontitis in diabetic and non-diabetic individuals: A case-control study

AIM

The aim of the present study was to evaluate the distribution of single-nucleotide polymorphisms (SNP) (variants FOKI [rs2228570], CDX2 [rs47908762], and GATA [rs4516035]) in the vitamin D receptor in individuals with type 2 diabetes mellitus and chronic periodontitis (DM2 + CP), CP alone, and healthy individuals, and to investigate the relationship with susceptibility to CP.

METHODS

In total, 280 individuals (116 with DM2 + CP, 95 with CP alone, and 69 healthy individuals) were genotyped using real-time polymerase chain reaction with allele-specific probes. Significant differences (P < .05) were found among the groups with regard to socio-epidemiological variables (sex, marital status, income, smoking habit, and schooling) and clinical-epidemiological variables (age, number of teeth, probing depth, clinical attachment loss, gingival bleeding index, and visible plaque index).

RESULTS

The C allele was significantly more frequent among the healthy individuals (34.8%) than those with DM2 + CP (23.5%) (odds ratio [OR] = .58, 95% confidence interval [CI]: . 35-.94, P = .022). Likewise, the CC allele was significantly more frequent among healthy individuals (11.6%) than those with DM2 + CP (2.6%) (OR = .17, 95% CI: .03-.79, P = .015).

CONCLUSION

The results suggest that the presence of these variants could lead to a lower susceptibility to DM2 and CP. No other significant differences among groups were found for the other SNP investigated.

Association of vitamin D receptor BsmI, TaqI, FokI, and ApaI polymorphisms with susceptibility of chronic periodontitis: A systematic review and meta-analysis based on 38 case -control studies

BACKGROUND

There has been increasing interest in the study of the association between Vitamin D receptor (VDR) gene polymorphisms and risk of chronic periodontitis. However, the results remain inconclusive. To better understand the roles of VDR polymorphisms (BsmI, TaqI, FokI, and ApaI) in chronic periodontitis susceptibility, we conducted this systematic review and meta-analysis.

MATERIALS AND METHODS

The PubMed, Google Scholar, and Web of Science database were systemically searched to determine all the eligible studies about VDR polymorphisms and risk of chronic periodontitis up to April 2017. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between VDR polymorphisms and chronic periodontitis risk. All the statistical analyses were performed by Comprehensive Meta-Analysis. All P values were two-tailed with a significant level at 0.05.

RESULTS

Finally, a total of 38 case-control studies in 19 publications were identified which met our inclusion criteria. There are ten studies with 866 chronic periodontitis cases and 786 controls for BsmI, 16 studies with 1570 chronic periodontitis cases and 1676 controls for TaqI, five studies with 374 chronic periodontitis cases and 382 controls for FokI, and seven studies with 632 chronic periodontitis cases and 604 controls for ApaI. Overall, no significant association was observed between VDR gene BsmI, TaqI, FokI, and ApaI polymorphisms and risk of chronic periodontitis in any genetic model. Subgroup analysis stratified by ethnicity suggested a significant association between BsmI polymorphism and chronic periodontitis risk in the Caucasian subgroup under allele model (A vs. G: OR = 1.747, 95% CI = 1.099-2.778, P = 0.018). Further, no significant associations were observed when stratified by Hardy-Weinberg equilibrium status for BsmI, TaqI, and ApaI.

CONCLUSION

Our results suggest that BsmI, TaqI, FokI, and ApaI polymorphisms in the VDR gene might not be associated with risk of chronic periodontitis in overall population.

Association of vitamin D receptor gene polymorphism (VDR) with vitamin D deficiency, metabolic and inflammatory markers in Egyptian obese women

Vitamin D deficiency might contribute to the pathogenesis of metabolic syndrome and could cause immune disturbance. The aim of this study is to analyze the associations between Vitamin D receptor (VDR) gene polymorphism, serum 25-hydroxy vitamin D, metabolic and inflammatory biomarkers in Egyptian obese women. The study included 201 obese women with vitamin D deficiency and 249 obese matched age healthy controls with sufficient vitamin D levels. Their age ranged between 25 and 35 years. Inflammatory biomarkers (interleukin-6 and C-reactive protein) and serum 25(OH) D were measured by enzyme-linked immunosorbent assay. Insulin resistance (IR) was determined by the homeostasis model assessment of insulin resistance (HOMA-IR).Vitamin D receptor (VDR) gene polymorphisms of FokI, ApaI, and TaqI were studied by PCR using the restriction fragment length polymorphism (RFLP) technique. Obese women with vitamin D deficiency had significant higher values of inflammatory and metabolic parameters compared to controls. Multivariable-logistic regression showed associations between 25(OH) D deficiency and metabolic components when comparing cases with controls. Moreover, cases carrying polymorphic alleles showed significant lower levels of serum 25(OH) D and higher HOMA-IR, blood pressure levels and lipid parameters compared to those with the wild type homozygote in obese cases with vitamin D deficiency. Vitamin D deficiency in Egyptian obese women with vitamin D deficiency is associated with abnormal metabolic components and abnormal inflammatory biomarkers. Moreover, VDR polymorphisms play important role in immune and inflammation status.

Association Study of Vitamin D Receptor (VDR) - Related Genetic Polymorphisms and their Haplotypes with Chronic Periodontitis in Colombian Population

INTRODUCTION

There is strong evidence that both genetic and environmental factors may affect the periodontal clinical status. However, epidemiological evidence on the association between Vitamin D Receptor (VDR) polymorphisms and Chronic Periodontitis (CP) has been inconsistent.

AIM

The focus of this study was to identify if a possible association between VDR Single-Nucleotide Polymorphisms (SNPs) may be implicated in the aetiopathogenesis of CP in Colombian population.

MATERIALS AND METHODS

One hundred and ten CP patients and 50 Healthy Controls (HC) were recruited. Periodontal status was assessed based on probing depth, clinical attachment level, extent, and severity of periodontal breakdown. The polymerase chain reaction-restriction fragment length polymorphism method was used to identify the VDR rs7975232, rs1544410, rs2228570, and rs731236 SNPs from saliva samples. Odds Ratios (ORs) along with their 95% Confidence Intervals (CIs) were computed to compare the distribution of genotypes/alleles between HC and CP patients, alongside with analysis of Linkage Disequilibrium (LD) and haplotype associations between SNPs. Also, an analysis of the interaction between genetic findings and those significant demographic factors was performed for all SNPs.

RESULTS

There was no association neither between the different genotypes/allele frequencies nor haplotypes and CP. Similarly, no significant differences in extent or severity amongst genotype/allele groups were observed. Even so, interaction analysis revealed significant synergistic interactions between each SNP and age associated with the disease status.

CONCLUSION

Although these results do not support that VDR SNPs could be identified as independent risk predictor variables for CP in the Colombian population, synergistic biological interactive effects of all these SNPs related to age might play a significant role in the pathogenic pathways of CP.

Inflammatory mediator polymorphisms associate with initial periodontitis in adolescents

Several studies have addressed cytokine gene polymorphisms and their possible associations with periodontitis. We examined the association between salivary anti- and pro-inflammatory mediator polymorphisms and initial periodontitis in Finnish adolescents, taking into account the effect of smoking. Salivary samples of 93 clinically examined adolescents from Eastern Finland were analyzed. Their oral health and smoking habits were recorded. Periodontal probing depth (PPD), and bleeding on probing (BOP) at four sites per tooth, root calculus (RC), and visible plaque index (VPI) were recorded from the index teeth. Salivary MMP-8 median values were assessed. The sites with ≥4 mm PD were categorized as follows: PPD1 = one or more ≥4 mm pocket, PPD2 = two or more ≥4 mm pockets, and PPD3 = three or more ≥4 mm pockets. Genomic DNA was extracted from 300 μl of the saliva samples by genomic QIAamp® DNA Blood Mini Kit and genotyped for polymorphisms. Genetic variants for genotyping were selected from the following genes of interest: S100A8, FCGR2A, FCGR2B, IL10, MMP8, MMP3, MMP13, VDR, TLR4, MMP2, MPO, ELANE, IL1A, IL1B, IL1RN, CD28, MMP9, DDX39B, NFKBIL1, LTA, TNF, SOD2, IL6, TLR4, TIMP1, and SYN1. After false discovery rate control (FDR), polymorphisms in MMP3 (rs679620, rs520540, rs639752), CD28 (rs3116496), and VDR (rs2228570) associated (FDR q < 0.05) with deepened periodontal pockets. Smoking did not affect the results. Genetic polymorphisms of pro-inflammatory mediators MMP3, CD28, and VDR seem to link to initial periodontitis.

Vitamin D and Its Relevance in the Etiopathogenesis of Oral Cavity Diseases

Vitamin D belongs to a group of fat-soluble secosteroids which assume many roles in the human organism. In humans the most important forms are vitamin D3 and vitamin D2. Their primary function is the regulation of the calcium and phosphorus balance, which promote the growth of healthy bony tissue. Studies over the past few years have revealed a much wider role of vitamin D involving the aging processes, carcinogenesis, the carbohydrate balance as well as the effects on the course of various infections. In this paper we discuss the basic functions of vitamin D in the human body and the mechanisms of its activity and we summarize recent reports on the impact of vitamin D on the oral cavity with a special emphasis on autoimmunologic diseases, including: recurrent aphthous stomatitis, Behçet syndrome and Sjögren syndrome.

Association between vitamin D receptor gene polymorphisms and chronic periodontitis among Libyans

BACKGROUND

Chronic periodontitis (CP) is a common oral disease characterized by inflammation in the supporting tissue of the teeth 'the periodontium', periodontal attachment loss, and alveolar bone loss. The disease has a microbial etiology; however, recent findings suggest that the genetic factors, such as vitamin D receptor (VDR) gene polymorphisms, have also been included.

AIM

Investigation of the relationship between VDR gene polymorphisms and CP among Libyans.

MATERIALS AND METHODS

In this study, we examined 196 unrelated Libyans between the ages of 25 and 65 years, including 99 patients and 97 controls. An oral examination based on Ramfjord Index was performed at different dental clinics in Tripoli and information were collected using a self-reported questionnaire. DNA was extracted from buccal swabs; the VDR ApaI, BsmI, and FokI polymorphisms were genotyped using polymerase chain reaction and were sequenced using Sanger Method.

RESULTS

A significant difference in the newly detected ApaI SNP C/T rs#731236 was found (p=0.022), whereas no significant differences were found in ApaI SNP G/T rs#7975232, BsmI SNP A/G rs#1544410, and FokI SNP A/G rs#2228570 between patients and controls (p=0.939, 0.466, 0.239), respectively.

CONCLUSION

VDR ApaI SNP C/T rs#731236 may be related to the risk of CP in the Libyan population.

Association between vitamin D receptor gene polymorphisms (Fok1 and Bsm1) and osteoporosis: a systematic review

Osteoporosis is a health concern characterized by reduced bone mineral density (BMD) and increased risk of fragility fractures. Many studies have investigated the association between genetic variants and osteoporosis. Polymorphism and allelic variations in the vitamin D receptor gene (VDR) have been found to be associated with bone mineral density. However, many studies have not been able to find this association. Literature review was conducted in several databases, including MEDLINE/Pubmed, Scopus, EMBASE, Ebsco, Science Citation Index Expanded, Ovid, Google Scholar, Iran Medex, Magiran and Scientific Information Database (SID) for papers published between 2000 and 2013 describing the association between Fok1 and Bsm1 polymorphisms of the VDR gene and osteoporosis risk. The majority of the revealed papers were conducted on postmenopausal women. Also, more than 50% studies reported significant relation between Fok1, Bsm1 and osteoporosis. Larger and more rigorous analytical studies with consideration of gene-gene and gene-environment interactions are needed to further dissect the mechanisms by which VDR polymorphisms influence osteoporosis.

Association of vitamin D and vitamin D receptor gene polymorphisms with chronic inflammation, insulin resistance and metabolic syndrome components in type 2 diabetic Egyptian patients

Background

To date the published data concerning the possible interplay between vitamin D (VitD) and Vit D receptor (VDR) gene polymorphism with the immune/inflammatory mediators in type 2 diabetes mellitus (DM) is insufficient. Some of the immune non-classical actions of vitamin D may point to its role in the pathogenesis of type 2 DM through down-regulation of cytokines (IL-6). Although there is evidence to support a relationship among vitamin D status, chronic inflammation and insulin resistance, the underlying mechanism requires further exploration. We aimed to investigate the role of vitamin D in chronic inflammation and insulin resistance in type 2 DM. Moreover, to examine the association of VDR gene polymorphisms [VDR 2228570 C > T (FokI); VDR 1544410 A > G (BsmI)] with the components of metabolic syndrome (MetSyn) in type 2 diabetic Egyptian patients .

Subjects and methods

A total of 190 subjects were enrolled in this study, 60 controls and 130 type 2 diabetic patients (Group II). Group II was subdivided into 63 patients without MetSyn (subgroup IIa) and 67 patients with MetSyn (subgroup IIb). Genetic analysis for VDR gene polymorphisms was done in all subjects. VitD and IL-6 plasma levels were estimated.

Results

The TT genotype for the VDR FokI was significantly more frequent in subgroup IIb than in subgroup IIa and controls (X² = 6.83, P = 0.03 and X² = 16.592, P = 0.000) respectively. The T allele was more frequent in the MetSyn group as compared to diabetics without MetSyn (p = 0.001), odds ratio (OR) and 95% CI for the T allele of C > T (FokI) = 2.30 (1.37–3.86). We did not detect any significant difference in VDR BsmI genotypes between patients and control groups (P = 0.947). FokI VDR was significantly associated with the lipid profile parameters, VitD and IL-6 plasma levels in subgroup IIa and associated with HOMA-IR, insulin, VitD, IL-6 levels, waist circumference (WC) and body mass index (BMI) in subgroup IIb while BsmI VDR variant was associated only with VitD values in both subgroups.

Conclusion

The present study suggests an interaction between VDR polymorphisms and important components of MetSyn, VitD and pro-inflammatory cytokines (IL-6). FokI VDR polymorphisms may be linked to mild inflammation and insulin resistance and might represent a genetic determinant for developing MetSyn in type 2 diabetic Egyptian patients. The challenge is determining the mechanisms of VitD action for recommendation of VitD supplementation that reduces the risks of MetSyn, insulin resistance and progression to type 2 diabetes.

Vitamin D: relevance in dental practice

OBJECTIVE

The potential role of VDR gene variations in modulating periodontal susceptibility have been a subject of scientific investigations. The aim of this paper is to perform a literature review of the potential correlation between Vitamin D Receptor (VDR) gene polymorphisms and periodontal disease.

MATERIALS AND METHODS

A PubMed literature search was made using "vitamin d receptor polymorphisms periodontal disease" as keys words. Only clinical studies in "Humans" as species and "English" as language were considered. Titles and abstracts of all identified records were examined to determine if the candidate articles contained sufficient information on the association of the VDR polymorphisms and the risk of development periodontal disease.

CONCLUSIONS

Vitamin D may affect the risk of developing periodontal disease via an effect on bone mineral density or via immunomodulatory effects. There are scientific evidences about the correlation between some VDR polymorphisms, periodontitis and bone metabolism. The use of new simple and economics diagnostic techniques of genetic screening, allows to the dental specialists to identify periodontal patients with possible decreased bone mineral density. The complete acquisition of awareness by dentists of the strong relationship between skeletal bone density with periodontal health and osteointegrated implant success, could open a new therapeutic approach for periodontists with an important role in the early detection of osteoporosis and a better patient compliance of the periodontal therapy.

VDR gene polymorphisms, interaction with smoking and risk of periodontal disease in Japanese women: the Kyushu Okinawa maternal and child health study

Epidemiological evidence on the relationship between vitamin D receptor (VDR) polymorphisms and periodontal disease is inconsistent. We investigated associations between four VDR single-nucleotide polymorphisms (SNPs) including rs731236 (TaqI), rs7975232 (ApaI), rs1544410 (BsmI) and rs2228570 (FokI), and the risk of periodontal disease among young Japanese women. Cases included 131 women who had at least one tooth with a probing depth of 3.5 mm or deeper. Controls included 1019 women without periodontal disease. Adjustment was made for age, region of residence, education, toothbrushing frequency and use of an interdental brush. Compared with the AA genotype of SNP rs731236, the GG genotype had a significantly increased risk of periodontal disease: the adjusted OR was 3.68 (95% confidence interval: 1.06-12.78). There were no significant relationships between SNPs rs7975232, rs1544410 or rs2228570 and periodontal disease. None of the haplotypes were significantly related to periodontal disease. Compared with subjects with the AA or AG genotype of SNP rs731236 who had never smoked, those with the GG genotype who had ever smoked had a significantly increased risk of periodontal disease; nevertheless, neither multiplicative nor additive interaction was significant. The additive interaction between SNP rs7975232 and smoking was significant, although the multiplicative interaction was not statistically significant. No multiplicative or additive interactions were observed between the other SNPs and smoking. Our results indicated that VDR SNP rs731236 might be associated with periodontal disease. In addition, we present new evidence for a biological interaction between VDR SNP rs7975232 and smoking that affects periodontal disease.

Association analysis of clinical aspects and vitamin D receptor gene polymorphism with external apical root resorption in orthodontic patients

INTRODUCTION

Vitamin D is responsible for the regulation of certain genes at the transcription level, via interaction with the vitamin D receptor, and influences host immune responses and aspects of bone development, growth, and homeostasis. Our aim was to investigate the association of TaqI vitamin D receptor gene polymorphism with external apical root resorption during orthodontic treatment.

METHODS

Our subjects were 377 patients with Class II Division 1 malocclusion, divided into 3 groups: (1) 160 with external apical root resorption ≤1.43 mm, (2) 179 with external apical root resorption >1.43 mm), and (3) 38 untreated subjects. External apical root resorption of the maxillary incisors was evaluated on periapical radiographs taken before and after 6 months of treatment. After DNA collection and purification, vitamin D receptor TaqI polymorphism analysis was performed by polymerase chain reaction-restriction fragment length polymorphism. Univariate and multivariate analyses were performed to verify the association of clinical and genetic variables with external apical root resorption (P <0.05).

RESULTS

There was a higher proportion of external apical root resorption in orthodontically treated patients compared with the untreated subjects. In patients orthodontically treated, age higher than 14 years old, initial size of the maxillary incisor root superior to 30 mm, and premolar extraction were associated with increased external apical root resorption. Genotypes containing the C allele were weakly associated with protection against external apical root resorption (CC + CT × TT [odds ratio, 0.29; 95% confidence interval, 0.07-1.23; P = 0.091]) when treated orthodontic patients were compared to untreated individuals.

CONCLUSIONS

Clinical factors and vitamin D receptor TaqI polymorphism were associated with external apical root resorption in orthodontic patients.

VDR TaqI polymorphism is associated with chronic periodontitis in Italian population

AIM

The aim of this study is to investigate the relationship between a vitamin D receptor polymorphism and the diagnosis of periodontal disease in non-smoker Italian patients with aggressive and chronic periodontitis.

MATERIALS AND METHODS

DNA was obtained from the internal cheek mucosa of 115 patients with chronic periodontitis, 58 with aggressive periodontitis and 65 healthy controls. Allelic discrimination was performed using TaqMan SNP Genotyping Assays. Genotype and allele frequencies were calculated.

RESULTS

Comparisons between diseased patients and healthy controls showed significant differences. Moreover, calculating the odds ratio, individuals with the TT genotype, was more susceptible than individuals with tt to chronic periodontitis and individuals with Tt to aggressive periodontitis. Interestingly, the dominant model (TT + Tt vs. tt) was applicable to chronic periodontitis, whilst for aggressive periodontitis the recessive model (TT vs. Tt + tt) gave the highest odds ratio.

CONCLUSIONS

These data indicated that VDR TaqI polymorphism is differentially associated with development of chronic periodontitis and aggressive periodontitis in Italian population. The study of VDR polymorphisms may therefore be essential for the prevention of periodontitis and for a pre-treatment periodontal and/or for implant assessment. Moreover VDR TaqI polymorphism could be useful to discriminate between aggressive and chronic forms of periodontal disease.

BsmI, TaqI, ApaI, and FokI polymorphisms in the vitamin D receptor gene and periodontitis: a meta-analysis of 15 studies including 1338 cases and 1302 controls

AIM

A meta-analysis was conducted in order to investigate the potential association of vitamin D receptor (VDR) gene polymorphisms with susceptibility to aggressive and chronic periodontal disease.

MATERIAL AND METHODS

A database search yielded a total of 15 studies involving 1338 cases and 1302 controls. Four polymorphisms were included in the meta-analysis: VDR TaqI (rs731236), VDR BsmI (rs1544410), VDR FokI (rs2228570), and VDR ApaI (rs7975232). Odds ratios (ORs) along with their 95% confidence intervals (CIs) were computed to compare the distribution of alleles and genotypes between cases and controls.

RESULTS AND CONCLUSIONS

The combined results based on all studies showed that (1) chronic periodontitis cases had a significantly lower frequency of bb genotype of BsmI [OR=0.63, 95% CI=0.42, 0.94; p=0.02] in Asians; (2) chronic periodontitis cases had a significantly higher frequency of AA genotype of ApaI (OR=2.20, 95% CI=1.39, 3.48; p<0.001) in Asians; (3) chronic periodontitis cases had a weak significantly higher frequency of TT genotype of TaqI (OR=1.86, 95% CI=1.002, 3.46; p=0.049) in Asians. After Bonferroni's correction, we found that in Asians chronic periodontitis cases still had a significantly higher frequency of AA genotype of ApaI. No significant difference was found in any genotype of FokI. No association was found for all the VDR gene polymorphisms examined as far as the aggressive form of the disease is concerned. Future studies need to focus on the possible biological consequences and mechanisms of the VDR genetic variants. The current findings confirm that VDR gene is a candidate gene for periodontitis.

Microbiological composition associated with vitamin D receptor gene polymorphism in chronic periodontitis

The aim of this cross-sectional study was to examine the relationship between the composition of the subgingival microbiota and the vitamin D receptor (VDR) gene polymorphism in Brazilian adults with chronic periodontitis. The clinical parameters of probing depth, clinical attachment level, bleeding on probing, plaque accumulation and suppuration were measured in 60 Caucasian adults who were divided into two groups: 30 healthy individuals (control) and 30 with chronic periodontitis (ChP). Subgingival plaque samples were collected from 6 sites per subject and analyzed for 38 bacterial species using the Checkerboard DNA-DNA Hybridization. DNA was obtained from the subjects' epithelial cells by scraping the buccal mucosa and using a mouthwash containing 3% of glucose. Polymorphism in the VDR gene was analyzed by the polymerase chain reaction (PCR), followed by Taql digestion (RFLP). The healthy subjects presented significantly lower levels (0.3 x 10(7) +/- 0.7 x 10(7)) of total microbial counts in comparison with subjects with chronic periodontitis (4.5 x 10(7) +/- 2.9 x 10(7)). Regarding the occurrence of VDR polymorphism, it was observed that the Tt genotype was more prevalent in the Periodontitis group (60%) than in the Healthy group (30%), while the prevalences of the TT genotype were 23.3% and 53.3%, respectively (Chi-square test, p < 0.05). No difference was found in the composition of subgingival microbiota among the VDR genotypes evaluated for the Healthy and Periodontitis groups. In conclusion, the Tt genotype was associated with periodontal disease; however, no association with the subgingival microbiota was observed.

Gene polymorphisms in chronic periodontitis

We aimed to conduct a review of the literature for gene polymorphisms associated with chronic periodontitis (CP) susceptibility. A comprehensive search of the literature in English was performed using the keywords: periodontitis, periodontal disease, combined with the words genes, mutation, or polymorphism. Candidate gene polymorphism studies with a case-control design and reported genotype frequencies in CP patients were searched and reviewed. There is growing evidence that polymorphisms in the IL1, IL6, IL10, vitamin D receptor, and CD14 genes may be associated with CP in certain populations. However, carriage rates of the rare (R)-allele of any polymorphism varied considerably among studies and most of the studies appeared under-powered and did not correct for other risk factors. Larger cohorts, well-defined phenotypes, control for other risk factors, and analysis of multiple genes and polymorphisms within the same pathway are needed to get a more comprehensive insight into the contribution of gene polymorphisms in CP.

Vitamin D and periodontal disease

1,25-Dihydroxyvitamin D(3) [1,25(OH)(2)D(3); 1,25-dihydroxycholecalciferol or calcitriol] is the active form of vitamin D(3), a lipid-soluble vitamin that plays a role in calcium and bone metabolism. Recently, vitamin D(3) has been shown to function in cancer prevention, immunity and cardiovascular regulation. 1,25(OH)(2)D(3) exhibits physiological and pharmacological effects by activating the vitamin D receptor (VDR), a transcription factor of the nuclear receptor superfamily. 1,25(OH)(2)D(3) plays a role in maintaining oral health through its effects on bone and mineral metabolism and innate immunity, and several VDR gene polymorphisms have been reported to be associated with periodontal disease. VDR ligands should prove to be useful in the treatment and prevention of periodontal disease.