GC Gene Polymorphisms and Vitamin D-Binding Protein Levels Are Related to the Risk of Generalized Aggressive Periodontitis

Search for Disease-Specific Genetic Markers Originated from the Vitamin D Binding Protein Gene Polymorphisms in the Multiple Sclerosis Cohort in the Latvian Population

Vitamin D is crucial for immune regulation, and its deficiency is linked to multiple sclerosis (MS). The GC gene encodes Vitamin D Binding Protein (VDBP), which regulates vitamin D transport and bioavailability. This study examines the association of GC polymorphisms (rs7041, rs4588) with MS susceptibility and their impact on 25-hydroxyvitamin D [25(OH)D] levels in a Latvian cohort. This case-control study included 296 MS patients and 253 healthy controls. Genotyping of rs7041 and rs4588 was conducted using restriction fragment length polymorphism analysis and validated by Sanger sequencing. Plasma 25(OH)D levels were measured in 131 MS patients using an enzyme-linked immunosorbent assay. Statistical analysis included Hardy-Weinberg equilibrium testing, Fisher's exact test, allelic and genotypic frequency comparisons to assess MS risk, and the Kruskal-Wallis test for 25(OH)D level differences among genotypes. Our findings indicate that the rare rs7041-T and rs4588-A alleles, along with their corresponding haplotypes, exhibit a protective effect against MS (p < 0.001; OR = 0.65 for rs4588-A; p < 0.01; OR = 0.70 for rs7041-T). Conversely, the common rs7041-G and rs4588-C alleles were associated with an increased MS risk (p < 0.05). Individuals with the Gc1F/1F isotype had the highest average 25(OH)D levels (29.31 ng/mL), while Gc1S/2 carriers had the lowest (21.53 ng/mL). Our results indicate that GC polymorphisms may influence the susceptibility of Latvians to MS and vitamin D status.

Serum Nutrients, Periodontitis and Biological Ageing

INTRODUCTION

Telomeres are nucleotide sequences found at the end of chromosomes, and their shortening is associated with chronological and biological ageing, oxidative stress and malnutrition. Shorter telomeres have been shown to be associated with periodontitis. Dietary nutrients are also influential factors in the aetiology and progression of periodontitis and other chronic inflammatory diseases. We tested the hypothesis that blood serum levels of folate, vitamin D, vitamin E, cis-β-carotene and/or β-cryptoxanthin are associated with telomere lengths and periodontitis and that these relationships are modified by factors that also affect periodontitis (e.g., age, sex, smoking, race/ethnicity).

METHODS

Laboratory and demographic data collected by the NHANES 1999-2002 survey of 10,793 study participants were analysed. The data included age (binned every 10 years starting at age 30), race/ethnicity (White, Black, Hispanic), sex (male, female), periodontitis (none/mild, moderate/severe), vitamin levels (low, medium, high), telomere lengths (base pairs) and smoking (yes, no). Statistical analyses were performed with ANOVA tests.

RESULTS

Periodontitis was significantly associated with vitamin D, vitamin E and cis-β-carotene. Telomere length was significantly associated with vitamin E and cis-β-carotene. There were statistically significant interactions between the following vitamins and covariates on telomere length: folate and sex, vitamin D and periodontitis, vitamin D and race/ethnicity and vitamin E and sex.

CONCLUSIONS

Certain blood nutrients may disrupt biological ageing, with periodontitis as a co-morbidity. Some of these relationships are modified by demographic variables such as sex and race/ethnicity.

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.

Vitamin D, periodontitis and tooth loss in older Irish adults

The aim of this study is to investigate whether 25-hydroxyvitamin D (25(OH)D) is associated with periodontitis and tooth loss in older adults. A total of 2346 adults underwent a detailed dental examination as part of the health assessment of a national population study - The Irish Longitudinal Study of Ageing. 25(OH)D analysis was performed on frozen non-fasting total plasma using LC-MS. The analysis included both multiple logistic regression and multinominal logistic regression to investigate associations between 25(OH)D concentration, periodontitis and tooth loss, adjusting for a range of potential confounders. Results of the analysis found the mean age of participants was 65·3 years (sd 8·2) and 55·3 % of the group were female. Based on the quintile of 25(OH)D concentration, participants in the lowest v. highest quintile had an OR of 1·57 (95 % CI 1·16, 2·13; P < 0·01) of having periodontitis in the fully adjusted model. For tooth loss, participants in the lowest v. highest quintile of 25(OH)D had a RRR of 1·55 (95 % CI 1·12, 2·13; P < 0·01) to have 1-19 teeth and a RRR of 1·96 (95 % CI 1·20, 3·21; P < 0·01) to be edentulous, relative to those with ≥ 20 teeth in the fully adjusted models. These findings demonstrate that in this cross-sectional study of older men and women from Ireland, 25(OH)D concentration was associated with both periodontitis and tooth loss, independent of other risk factors.

Sputum Vitamin D Binding Protein (VDBP) GC1S/1S Genotype Predicts Airway Obstruction: A Prospective Study in Smokers with COPD

Introduction

The vitamin D binding protein (VDBP, also known as GC-globulin) and vitamin D deficiency have been associated with chronic obstructive pulmonary disease (COPD). rs7041 and rs4588 are two single nucleotide polymorphisms of the VDBP gene, including three common allelic variants (GC1S, GC1F and GC2). Previous studies primarily assessed the serum levels of vitamin D and VDBP in COPD. However, less is known regarding the impact of the local release of VDBP on COPD lung function. Thus, we examined the association of sputum and plasma VDBP with lung function at baseline and at four years, and examined potential genetic polymorphism interactions.

Methods

The baseline levels of sputum VDBP, plasma VDBP and plasma 25-OH vitamin D, as well as the GC rs4588 and rs7041 genotypes, were assessed in a 4-year Finnish follow-up cohort (n = 233) of non-smokers, and smokers with and without COPD. The associations between the VDBP levels and the longitudinal decline of lung function were further analysed.

Results

High frequencies of the haplotypes in rs7041/rs4588 were homozygous GC1S/1S (42.5%). Higher sputum VDBP levels in stage I and stage II COPD were observed only in carriers with GC1S/1S genotype when compared with non-smokers (p = 0.034 and p = 0.002, respectively). Genotype multivariate regression analysis indicated that the baseline sputum VDBP and FEV1/FVC ratio at baseline independently predicted FEV1% at follow-up.

Discussion and Conclusion

The baseline sputum VDBP expression was elevated in smokers with COPD among individuals with the GC1S/1S genotype, and predicted follow-up airway obstruction. Our results suggest that the GC polymorphism should be considered when exploring the potential of VDBP as a biomarker for COPD.

Polymorphisms within vitamin D binding protein gene within a Preeclamptic South African population

Objectives: The vitamin D binding protein encoded by the GC gene contains two single nucleotide polymorphisms (rs4588 and rs7041) that have been associated with disease outcome, these include periodontitis coronary heart disease and hypertension. In pregnancy, these SNPs influence vitamin D metabolism that could result in hypertensive disorders such as PE. The etiology of PE, still remains elusive. The aim of this study was to evaluate the distribution of rs4588 and rs7041 within the GC gene among PE and normotensive pregnant women, residing in Durban, KwaZulu-Natal, South Africa. Study design: Our study consisted of n = 600 participants (normotensive (n = 246, N); early onset PE (n = 167, EOPE); and late-onset PE (n = 246, LOPE)). We extracted DNA from whole blood and genotyped for rs4588 and rs7041 SNPs using the TaqMan assay. Results: Regardless of HIV status, we observed the rs4588 (CC genotype) more frequently in PE (EOPE+LOPE) compared to the normotensive participants with an OD ratio of 0.74 (95% CI, 0.35-1.5; p < 0.001). We report a significant difference in the frequency of rs7041 (GT genotype) in the EOPE group compared to the normotensive group with an OD ratio of 11.48 (95% CI, 2.6-103.7; p < 0.001). The rs7041 GT genotype had a higher frequency in the EOPE compared to the LOPE group, with an OD ratio of 15.15 (95% CI, 2.3-639.2; p < 0.001). Conclusion: This is the first study to describe the prevalence of SNPs of the rs4588 and rs7041 within the GC gene in women with PE within the high HIV endemic area of KZN, South Africa. Notably, a significant association of the rs7041 (TT genotype) and rs4588 (CC genotype) occurred at a higher frequency in PE compared to the normotensive cohort. Future studies will examine the functional effect of the GC region in relation to pregnancy and vitamin D deficiency.

Epidemiologic evaluation of Nhanes for environmental Factors and periodontal disease

Periodontitis is a chronic inflammation that destroys periodontal tissues caused by the accumulation of bacterial biofilms that can be affected by environmental factors. This report describes an association study to evaluate the relationship of environmental factors to the expression of periodontitis using the National Health and Nutrition Examination Study (NHANES) from 1999-2004. A wide range of environmental variables (156) were assessed in patients categorized for periodontitis (n = 8884). Multiple statistical approaches were used to explore this dataset and identify environmental variable patterns that enhanced or lowered the prevalence of periodontitis. Our findings indicate an array of environmental variables were different in periodontitis in smokers, former smokers, or non-smokers, with a subset of specific environmental variables identified in each population subset. Discriminating environmental factors included blood levels of lead, phthalates, selected nutrients, and PCBs. Importantly, these factors were found to be coupled with more classical risk factors (i.e. age, gender, race/ethnicity) to create a model that indicated an increased disease prevalence of 2-4 fold across the sample population. Targeted environmental factors are statistically associated with the prevalence of periodontitis. Existing evidence suggests that these may contribute to altered gene expression and biologic processes that enhance inflammatory tissue destruction.

Serum Nutrient Levels and Aging Effects on Periodontitis

Periodontal disease damages tissues as a result of dysregulated host responses against the chronic bacterial biofilm insult and approximately 50% of US adults >30 years old exhibit periodontitis. The association of five blood nutrients and periodontitis were evaluated due to our previous findings regarding a potential protective effect for these nutrients in periodontal disease derived from the US population sampled as part of the National Health and Nutrition Examination Survey (1999⁻2004). Data from over 15,000 subjects was analyzed for blood levels of cis-β-carotene, β-cryptoxanthin, folate, vitamin D, and vitamin E, linked with analysis of the presence and severity of periodontitis. Moderate/severe disease patients had lower cis-β-carotene levels across all racial/ethnic groups and these decreased levels in moderate/severe periodontitis were exacerbated with age. β-cryptoxanthin demonstrated lower levels in severe disease patients across the entire age range in all racial/ethnic groups. Folate differences were evident across the various age groups with consistently lower levels in periodontitis patients >30 years and most pronounced in females. Lower levels of vitamin D were consistently noted across the entire age range of patients with a greater difference seen in females with periodontitis. Finally, an analytical approach to identify interactions among these nutrients related to age and periodontitis showed interactions of vitamin D in females, and folate with race in the population. These findings suggest that improving specific nutrient intake leading to elevated blood levels of a combination of these protective factors may provide a novel strategy to affect the significant increase in periodontitis that occurs with aging.

Impact of genetic influence on serum total- and free 25-hydroxyvitamin-D in humans

Serum 25-hydroxyvitamin D /25OHD/ levels in humans are determined primarily by environmental factors such as UV-B radiation and diet, including vitamin D intake. Although some genetic determinants of 25OHD levels have been shown, the magnitude of this association has not yet been clarified. The present study evaluates the genetic contribution to total- /t-25OHD/ and free-25OHD /f-25OHD/ in a representative sample of the Hungarian population (n = 462). The study was performed at the end of winter to minimize the effect of sunlight, which is a major determinant of serum vitamin D levels. Single nucleotide polymorphisms (SNPs) of five genes playing major roles in vitamin D metabolism were investigated (NADSYN1, DHCR7, GC, CYP2R1 and CYP24A1). The selected SNPs account for 13.1% of the variance of t-25OHD levels. More than half of the genetic effect on t-25OHD levels was explained by two polymorphisms (rs7935125 in NADSYN1 and rs2762941 in CYP24A1), which had not previously been investigated with respect to vitamin D metabolism. No SNPs exhibited association with f-25OHD levels. Unexpectedly, SNPs that showed univariate associations with vitamin D binding protein (DBP) levels were not associated with f-25OHD levels questioning the biological significance of these polymorphisms. The present study shows that t-25OHD levels are significantly influenced by genetic factors, however, the clinical significance of this observation remains to be defined, as variation in f-25OHD levels are marginally explained by genetic effects.