Association of the polymorphisms in promoter and intron regions of the interleukin-4 gene with chronic periodontitis in a Turkish population

A Systematic Review and Meta-Analysis on Multiple Cytokine Gene Polymorphisms in the Pathogenesis of Periodontitis

Aim

Periodontitis is an inflammatory disease that destroys both soft and hard periodontal tissues. However, a complex periodontal cytokine network remains unclear. This systematic review explored multiple cytokine gene polymorphisms in the pathogenesis of periodontitis.

Material and Methods

A systematic search was performed using the databases from previous publications, which indicated the association between cytokine polymorphisms and periodontitis pathogenesis. Meta-analysis was conducted using fixed or randomized models to calculate the significance of multiple cytokine polymorphisms. A total of 147 articles were analyzed with polymorphisms in 12 interleukins [Th1 (IL-2, IFN-γ, and TNF-α), Th2 (IL-4 and IL-13), Th17 (IL-1α, IL-1β, IL-6, and IL-17), and Treg cytokines (IL-10 and TGF-β)]. Doi plot was used to probe the occurrence of publication bias.

Results

The polymorphisms of IL-2 and TNF-α of Th1 cytokine family may be associated with the pathogenesis or the prevention of periodontitis risk, while the polymorphism of IFN-γ is not related to periodontitis risk. The polymorphisms for IL-4 and IL-13 of Th2 cytokine family are not found to be associated with the pathogenesis of periodontitis. For the polymorphisms of the members of Th17 cytokine family, different IL-1α polymorphisms may have inverse actions in the pathogenesis of periodontitis. IL-1β is a noteworthy cytokine biomarker in periodontitis development and progression. IL-6 may have a protective function in the inflammatory responses of periodontitis, and IL-17 has a weak relationship the inflammatory responses. The polymorphisms for the members of Treg cell cytokines may have a protective function against periodontitis risk. LFK indexes show the major asymmetry due to publication bias.

Conclusion

IL-1β is a notable cytokine biomarker in periodontitis risk. Treg cytokines favor an anti-inflammatory and protective environment. Further data are needed to confirm the present conclusion due to publication bias.

Genetic polymorphisms in the Interleukins IL1B, IL4, and IL6 are associated with concomitant periodontitis and type 2 diabetes mellitus in Brazilian patients

OBJECTIVE

To assess whether single nucleotide polymorphisms (SNPs) in the IL10, IL1A, IL1B, IL4, TNFA, IL6, OPG, RANK, and RANKL genes, "classically" related with periodontitis, could be associated with susceptibility to T2DM, and also with both diseases concomitantly.

BACKGROUND

There are common pathogenic mechanisms in type 2 diabetes mellitus (T2DM) and periodontitis, but the knowledge of the genetic aspect of this is limited. In patients affected by concomitant T2DM and periodontitis, whose incidence is increasing, there is scarce information regarding the gene-phenotype association, including whether there are genes able to influence both diseases as comorbidities.

METHODS

Periodontal clinical parameters and biochemical profile (Insulin, Fasting Glycemia, HbA1c, Triglycerides, Total Cholesterol, HDL-cholesterol, and LDL-cholesterol) data were obtained from 894 individuals divided into following three groups: Healthy (H; n = 347), Periodontitis (P; n = 348), and Periodontitis + T2DM (P + T2DM; n = 199). DNA from oral epithelial cells was collected for genotyping. Associations between SNPs and pathologies were tested by multiple logistic regression models, adjusting for age, sex, and smoking habits. We also investigated whether there are sex or smoking effects of each SNP in these phenotypes.

RESULTS

The rs1143634-GA (IL1B) SNP showed significantly less likely to develop P + T2DM for all population and mainly for women (adjusted OR = 0.37, 95% CI = 0.16-0.88), while women carrying the rs224320 CT (IL4) were more susceptible to develop P + T2DM (adjusted OR = 1.81, 95% CI = 1.04-3.15). Men carrying the rs1800795-CC (IL6) genotype were less likely to develop T2DM (adjusted OR = 0.12, 95% CI = 0.02-0.70, P = .01).

CONCLUSIONS

Some SNPs in the IL1B, IL4, and IL6 genes demonstrated sex-influenced association with concomitant periodontitis and T2DM, increasing the evidence of a common genetic component between these diseases and contributing with the understanding of their common pathogenic mechanisms.

IL4 gene VNTR polymorphism in chronic periodontitis in end-stage renal disease patients

OBJECTIVE

Interleukin-4 gene polymorphisms were found to be associated with periodontitis. The purpose of this case-control study was to evaluate association of IL4 VNTR polymorphism with periodontitis in patients with end-stage renal disease (ESRD).

SUBJECTS AND METHODS

We examined 180 ESRD patients with chronic periodontitis, 82 without CP and 180 healthy controls. Genomic DNA from all subjects was genotyped for the IL4 VNTR polymorphism by polymerase chain reaction (PCR).

RESULTS

Genotype distribution in all groups followed Hardy-Weinberg equilibrium. Significant differences in genotype and allele frequencies were observed between groups. The patient group had higher frequency of P1 allele than controls, with odds ratio for P1 allele 1.6 (95% CI 1.1-2.3) and P1P1 genotype 2.73 (95% CI 1.06-7.5). There were no differences in polymorphism distribution between ESRD patients without CP and controls. Periodontal disease was more severe in older patients (≥50 years). Similarly, patients with T2DM had more severe manifestation of CP than patients without diabetes (p = 0.01 for plaque index, p = 0.004 for bleeding index and p = 0.03 for gingival index).

CONCLUSION

Our findings suggest that VNTR polymorphism in IL4 gene might be a risk factor for chronic periodontitis in patients with ESRD.

Association between IL-4 and IL-4R Polymorphisms and Periodontitis: A Meta-Analysis

Background. Previous studies have revealed that gene polymorphisms of inflammatory factors may influence the development or progression of periodontitis, a main cause of tooth loss in adults; however, due to limitations of individual studies, inconsistent findings were reported. Objective. To meta-analytically investigate the relationship between periodontitis and the Interleukin-4 (IL-4) and Interleukin-4 receptor (IL-4R) gene polymorphisms. Methods. Databases were searched for relevant case-control studies. After study selection based on the predefined selection criteria, methodological quality assessment and data extraction were conducted independently by two reviewers, before subsequent statistical analyses. Results. 37 studies involving 4,385 patients and 5,168 controls were included. All the studied IL-4 polymorphisms were not significantly associated with periodontitis, except the -33C/T (CT versus CC: OR = 0.50, 95% CI = 0.28–0.88) associated with reduced AgP susceptibility. Positive association was found between IL-4R Q551 polymorphism and periodontitis susceptibility in three genetic models (R versus Q: OR = 1.59, 95% CI = 1.14–2.22; QR versus QQ: OR = 1.84, 95% CI = 1.21–2.80; RR + QR versus QQ: OR = 1.82, 95% CI = 1.22–2.72). Conclusions. A positive association exists between the IL-4R Q551R polymorphism and occurrence of CP. The IL-4 -33 CT genotype is negatively associated with the occurrence of AgP.

Association of interleukin-4 and interleukin-17F polymorphisms in periodontitis in Dravidian ethnicity

BACKGROUND:

Complex network of pro and anti-inflammatory cytokines are known to act in inflamed periodontal tissue. This study explores the distribution of interleukin (IL)-4 (+33 C/T) and IL-17F (7383A/G, 7488A/G) gene polymorphism in chronic and aggressive periodontitis subjects of Dravidian ethnicity.

MATERIALS AND METHODS:

This case control study consisted of 124 periodontitis individuals comprising of 63 chronic and 61 aggressive periodontitis subjects as cases, and control group consisted of 101 healthy subjects. All subjects were genotyped for IL-4 + 33C/T, IL-17F 7383A/G, 7488A/G by polymerase chain reaction amplification followed by TaqMan assay for IL-4 + 33C/T, restriction enzyme digestion and gel electrophoresis for IL-17F 7383A/G and sequencing for IL-17F 7488A/G.

RESULTS:

IL-4 + 33C/T was significantly associated with periodontitis (P < 0.05) at both allelic and genotypic level. In subgroup analysis also significant difference (P < 0.05) in allelic distribution between aggressive periodontitis and control group for loci IL-4 + 33C/T was noted. However, there was a lack of association between IL-17F 7383A/G and IL-17F 7488A/G with periodontitis and its sub-groups at both allelic and genotypic levels.

CONCLUSIONS:

In Malayalam speaking Dravidian population IL-4 + 33C/T loci appears to be an important risk factor for periodontal disease with a leaning towards aggressive periodontitis. The association between IL-17F at 7383A/G and 7488A/G loci with either chronic or an aggressive periodontitis could not be ascertained.

What do 'omic technologies have to offer periodontal clinical practice in the future?

BACKGROUND AND OBJECTIVE

Periodontal diseases are the most common chronic inflammatory diseases of humans and a major cause of tooth loss. Inflammatory periodontitis is also a complex multifactorial disease involving many cell types, cell products and interactions. It is associated with a dysregulated inflammatory response, which fails to resolve, and which also fails to re-establish a beneficial periodontal microbiota. There is a rich history of biomarker research within the field of periodontology, but exemplary improvements in analytical platform technologies offer exciting opportunities for discovery. These include the 'omic technologies, such as genomics, transcriptomics, proteomics and metabolomics, which provide information on global scales that can match the complexity of the disease. This narrative review focuses on the recent advances made in in vivo human periodontal research by use of 'omic technologies.

MATERIAL AND METHODS

The Medline database was searched to identify articles currently available on 'omic technologies with regard to periodontal research.

RESULTS

One hundred and sixty-one articles focusing on biomarkers of and 'omic advances in periodontal research were analysed for their contributions to the understanding of periodontal diseases.

CONCLUSION

The data generated by the use of 'omic technologies have huge potential to inform paradigm shifts in our understanding of periodontal diseases, but data management, analysis and interpretation require a thoughtful and systematic bioinformatics approach, to ensure meaningful conclusions can be made.

Vaginal and oral microbes, host genotype and preterm birth

Preterm birth (PTB) is a leading cause of infant mortality and morbidity in the US and across the globe. Infection and associated inflammation are important initiators for PTB pathways; an estimated 40% of PTBs are attributed to amniochorionic-decidual or systemic inflammation. Historically, intrauterine infections have been implicated in PTB; recent evidence suggests that infections remote from the fetal site may also be causative. There is strong epidemiological evidence that bacterial vaginosis and periodontitis--two syndromes characterized by perturbations in the normal vaginal and oral bacterial microflora, respectively--are linked to infection-associated PTB. Oral and vaginal environments are similar in their bacterial microbiology; identical bacterial species have been independently isolated in periodontitis and bacterial vaginosis. Periodontitis and bacterial vaginosis also share many behavioral and sociodemographic risk factors suggesting a possible common pathophysiology. Genetic polymorphisms in host inflammatory responses to infection are shared between bacterial vaginosis, periodontitis and PTB, suggesting common mechanisms through which host genotype modify the effect of abnormal bacterial colonization on preterm birth. We review the state of knowledge regarding the risk of PTB attributable to perturbations in bacterial flora in oral and vaginal sites and the role of host genetics in modifying the risk of infection-related PTB. We posit that bacterial species that are common in perturbed vaginal and oral sites are associated with PTB through their interaction with the host immune system.

Implications of cytokine gene polymorphisms on the orchestration of the immune response: lessons learned from oral diseases

Over the past 10 years, a plethora of information concerning the influence of gene polymorphisms on cytokine expression has been made available in the literature. Significant contribution to this field has come from studies of oral diseases, one of the widest spread health problems in the world, affecting hundreds of millions worldwide. Here we will discuss the importance of studies of gene polymorphism towards the identification of susceptible groups or prognostic indicators of oral disease. Additionally, we will highlight the differences in data obtained from genetically diverse populations and review the application of cytokine gene polymorphisms studies in oral diseases in autoimmune processes and parasitic infections.