Relationships between IL-6 gene polymorphism, low BMD and periodontitis in postmenopausal women

A Mendelian randomization study on the association of bone mineral density with periodontitis

OBJECTIVE

Observational studies indicated that individuals with osteoporosis could be at an increased risk of periodontitis. This study aimed to investigate whether there is a causal association of bone mineral density (BMD) with periodontitis using Mendelian randomization (MR).

MATERIALS AND METHODS

Summary statistics were sourced from genome-wide association study on BMD measured at different skeletal sites, including estimated heel BMD (eBMD, N = 426,824), forearm BMD (FA-BMD, N = 8143), femoral neck BMD (FN-BMD, N = 32,735), and lumbar spine BMD (LS-BMD, N = 28,498). Genetic variants of periodontitis (N = 45,563) and loose teeth (N = 461,031) were used as outcome surrogates. Inverse variance weighted meta-analysis (IVW) was adopted as main analyses. Other sensitivity MR approaches were used to boost power and account for pleiotropy.

RESULTS

IVW results suggested no evidence for a causal association of any phenotypes of BMD with periodontitis (eBMD, odds ratio [OR] = 0.984, 95% confidence interval [CI] = 0.885-1.083; FA-BMD, OR = 1.028, 95%CI = 0.864-1.193; FN-BMD, OR = 1.033, 95%CI = 0.896-1.169; LS-BMD, OR = 0.991, 95%CI =0.878-1.103; all P > 0.65). Such null associations were consistent through other sensitivity MR approaches. Similarly, no significant causal effects of BMD on loose teeth were found.

CONCLUSIONS

Within the limitation of the study, our MR estimates suggested that a decreased BMD is unlikely to substantially increase the risk of periodontitis.

The Role of Interleukin 6 in Periodontitis and Its Complications

Interleukin 6 (IL-6) is a pleomorphic pro-inflammatory cytokine that is strongly associated with local as well as systemic inflammatory processes. Its role in physiological and pathogenic processes throughout the human body has been the subject of numerous studies in recent years. Measurements of the IL-6 levels in gingival crevicular fluid (GFC), as well as in serum, can be important diagnostic and prognostic factors in periodontal diseases (PD) and in assessing their impact on a range of related inflammatory diseases. This narrative review explores the significant role of IL-6 in patients with periodontitis and its association with other widespread inflammatory pathologies.

Association of interleukin-1, interleukin-6, collagen type I alpha 1, and osteocalcin gene polymorphisms with early crestal bone loss around submerged dental implants: A nested case control study

STATEMENT OF PROBLEM

The reason for variations in peri-implant early crestal bone loss is unclear but may be due to genetic differences among individuals.

PURPOSE

The purpose of this nested case control study was to investigate the association of single-nucleotide polymorphisms of interleukin-1, interleukin-6, collagen type I alpha1, and osteocalcin genes to early crestal bone loss around submerged dental implants.

MATERIAL AND METHODS

Dental implants were placed in the mandibular posterior region (single edentulous space) of 135 participants selected according to predetermined selection criteria. Bone mineral density measurement by using dual energy X-ray absorptiometry, cone beam computed tomography scans at the baseline and after 6 months, and interleukin-1A-889 A/G (rs1800587), interleukin-1B-511 G/A (rs16944), interleukin-1B+3954 (rs1143634), interleukin-6-572 C/G (rs1800796), collagen type I alpha1 A/C (rs1800012), and osteocalcin C/T (rs1800247) genotyping were performed in all participants. Early crestal bone loss measured around dental implants was used to group participants into clinically significant bone loss (BL)>0.5 mm and clinically nonsignificant bone loss (NBL)≤0.5 mm. Early crestal bone loss was calculated as the mean of the difference of bone levels at the baseline and bone levels after 6 months as measured with cone beam computed tomography scans. The obtained data for basic characteristics, early crestal bone loss, and genotyping were tabulated and compared by using a statistical software program (α=.05).

RESULTS

AA genotype and the A allele frequency of interleukin-1B-511 and GG genotype and the G allele frequency of interleukin-6-572 were significantly higher in BL than in NBL (P<.05). Multiple logistic analysis suggested that interleukin-1B-511 AA/GG+AG and interleukin-6-572 GG/CC+CG genotype expression were significantly associated with early crestal bone loss (AA/GG+AG; P=.014, GG/CC+CG; P=.047) around dental implants. Other risk factors were not significantly different (P>.05).

CONCLUSIONS

Of the genes studied, individuals with interleukin-1B-511 AA (rs16944) or interleukin-6-572 GG (rs1800796) genotype had higher susceptibility to early crestal bone loss around dental implants.

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.

No Interaction Effect between Interleukin-6 Polymorphisms and Acid Ash Diet with Bone Resorption Marker in Postmenopausal Women

Background: Evidence is growing that a high-acid diet might accelerate the rate of bone loss, and gene polymorphisms such as Interleukin 6 (IL6) -174G/C and -572G/C are related to bone deterioration. However, no study of the interaction between diet and IL6 polymorphisms has been conducted among Asians. Thus, the objective of this study was to determine whether IL6 gene polymorphisms modified the association between dietary acidity and the rate of bone resorption. Methods: This cross-sectional study recruited 203 postmenopausal women (age ranged from 51 to 85 years old) in community settings. The dietary intakes of the participants were assessed using a validated interviewer-administered semi-quantitative food frequency questionnaire (FFQ), while dietary acid load (DAL) was estimated using net endogenous acid production (NEAP). Agena^® MassARRAY genotyping analysis and serum collagen type 1 cross-linked C-telopeptide (CTX1) were used to identify the IL6 genotype and as a bone resorption marker, respectively. The interactions between diet and single-nucleotide polymorphisms (SNPs) were assessed using linear regressions. Results: A total of 203 healthy postmenopausal women aged between 51 and 85 years participated in this study. The mean BMI of the participants was 24.3 kg/m². In IL6 -174 G/C, all the participants carried the GG genotype, while the C allele was absent. Approximately 40% of the participants had a high dietary acid load. Dietary acid load (B = 0.15, p = 0.031) and the IL6 -572 CC genotype group (B = 0.14, p = 0.044) were positively associated with a higher bone resorption. However, there was no moderating effect of the IL6 genetic polymorphism on the relationship between and acid ash diet and bone resorption markers among the postmenopausal women (p = 0.79). Conclusion: High consumption of an acid ash diet and the IL6 -572 C allele seem to attribute to high bone resorption among postmenopausal women. However, our finding does not support the interaction effect of dietary acidity and IL6 (-174G/C and -572G/C) polymorphisms on the rate of bone resorption. Taken together, these results have given scientific research other candidate genes to focus on which may interact with DAL on bone resorption, to enhance planning for preventing or delaying the onset of osteoporosis among postmenopausal women.

Level of pain intensity, cytokine profiling and microbial load after photodynamic therapy in acute severe pericoronitis

AIM

We evaluated the efficacy of antimicrobial photodynamic therapy (A-PDT) in the reduction of pain intensity and performed cytokine profiling and measurement of microbiological parameters in patients with acute pericoronitis.

METHODS

Sixty patients with age range 14-19 years were randomized into two groups: 'A-PDT group' which received additional A-PDT with conventional protocol, and 'conventional protocol group' (CPG) without A-PDT. Present pain intensity (PPI) were investigated using McGill Pain Questionnaire (MPQ) and Visual Analogue Scale (VAS). Gingival crevicular fluid were sampled to evaluate the levels of interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) and quantified using enzyme-linked immunosorbent assay. Microbial plaque was collected to evaluate total counts of Porphyromonas gingivalis and Tannerella forsythia expressed as log colony forming unit (CFU)/mL. Level of pain intensity, cytokine profiling and microbial load were assessed at baseline (B0), and post treatment F₇ (Day 7) and F₁₄ (Day 14).

RESULTS

A total of 59 patients (30 CPG and 29 A-PDT) completed the clinical trial. Present pain intensity scores statistically significantly reduced from B₀ to F₇ in both treatment groups (p < 0.05). For VAS, both groups showed statistically significant reduction in pain scores at F₁₄ only when compared with baseline (p < 0.05). There was no inter-group significant difference at any time point for either pain scores (p > 0.05). Only TNF-α showed statistically significant reduction with A-PDT compared to CPG at both F₇ and F₁₄. CPG group showed significant reduction for only T. forsythia at both follow-up points. The microbial counts for P. gingivalis and T. forsythia significantly reduced in A-PDT groups compared to CPG group at both F₇ and F₁₄.

CONCLUSION

The results of this study indicate that A-PDT may be a reliable treatment option in pericoronitis for the reduction of TNF-α and microbial load. However, A-PDT does not have any effect in the reduction of pain.

MAEA rs6815464 polymorphism and periodontitis in postmenopausal Japanese females: A cross-sectional study

OBJECTIVES

Macrophage erythroblast attacher (MAEA) is a membrane protein that regulates the development of mature macrophages by mediating attachment with erythroblasts. A polymorphism rs6815464 (C/G) in MAEA gene was reported to be associated with type II diabetes. Along with diabetes, osteoporosis shows an increased prevalence in postmenopausal females, and both diseases have been reported to be associated with periodontitis. Therefore, we explored the relevance of the MAEA polymorphism to periodontitis, bone mineral density (BMD) and haemoglobin A1c (HbA1c).

DESIGN

This was a cross-sectional study with the final sample comprised of 344 postmenopausal Japanese females. Probing pocket depth (PPD) and clinical attachment level (CAL) were measured. Genotype was determined by TaqMan assay. Blood biochemical parameters and BMD of the lumbar spine were evaluated.

RESULTS

No differences were found in age, body mass index, HbA1c, BMD, number of teeth, bone metabolism parameters between the genotypes. Mean CAL and percentage of sites with PPD or CAL ≥ 5 mm were higher in the G-allele carriers than in the non-carriers. Multiple logistic regression analyses revealed that G-allele carriage was associated with severe periodontitis (odds ratio = 3.73, 95% CI = 1.36-10.19).

CONCLUSION

Our results suggested that the MAEA gene polymorphism was independently associated with severe periodontitis.

Clinical response to non-surgical periodontal treatment in patients with interleukin-6 and interleukin-10 polymorphisms

Background

Genetic polymorphisms are commonly associated with altered transcriptional activity and possibly make individuals more susceptible to periodontal disease development, increased disease severity and poor treatment outcome. The study aimed to determine the effect of Interleukin-6 (IL-6) -572 G/C (rs1800796) and IL-10 -592 C/A (rs1800872) polymorphisms on the outcomes of non-surgical periodontal therapy in a Caucasian population.

Material and Methods

Sixty-eight patients with chronic periodontal disease were grouped according to their genotype: IL-6, IL-10, IL-6 and IL-10 susceptible (SCP) and non-susceptible (NSCP). All individuals were clinically evaluated at the first visit, and blood sample were collected from patients after checking the inclusion and exclusion criteria of the study. All patients received non-surgical periodontal therapy from a single-blinded periodontist. Clinical periodontal measurements were repeated 45 days after therapy.

Results

This population mean aged 47.63 years included 52.2% females and 58.2% non-smokers. Following DNA separation and genotyping, 65.7% of patients were homozygous carriers of the IL-6 - 572G; 49.3% were carriers of the IL-10 -592A- allele (AA and CA genotypes); and 35.8% carried SCP genotypes for both polymorphisms. The clinical parameters after therapy were not associated with the genotype status. The multiple logistic regression analysis did not show any statistically significant association between the genotypes and the variables tested.

Conclusions

Within the limitations of this longitudinal study, it can be suggested that IL-6 -572 G/C and IL-10 -592 C/A polymorphisms as well as their combination do not influence the outcome of nonsurgical periodontal therapy in Caucasian patients diagnosed with chronic periodontal disease.

Key words:Gene polymorphism, genetics, interleukins, periodontal disease, treatment outcome.