Interleukin-10 gene polymorphisms and chronic/aggressive periodontitis susceptibility: A meta-analysis based on 14 case-control studies

Association of IL-10 -1082A>G, -819C>T, and -592C>A polymorphisms with susceptibility to chronic and aggressive periodontitis: a systematic review and meta-analysis

OBJECTIVES

Several epidemiological studies have evaluated association of interleukin 10 (IL-10) polymorphisms with risk of periodontitis. However, the results remain conflicting and inconclusive. Here, we carried out a comprehensive systematic review and meta-analysis to evaluate the association of IL-10 -1082A>G, -819C>T, and -592C>A polymorphisms with risk of chronic (CP) and aggressive (CP) periodontitis.

METHODS

Electronic databases including PubMed, Science Direct, SciELO, and CNKI were systematically searched to identify all relevant studies published up to 01 June 2020.

RESULTS

A total of 60 case-control studies with 5313 cases and 6528 controls met our inclusion criteria. Overall, the pooled data showed that the IL-10 -592C>A polymorphism was statistically associated with increased risk of periodontitis in the overall population, while no significant association was identified for IL-10 -1082A>G and IL-10 -819C>T polymorphisms. The subgroup analysis by ethnicity revealed that the IL-10 -1082A>G polymorphism was significantly associated with periodontitis risk in Caucasians, IL-10 -819C>T polymorphism in mixed population, and IL-10 -592C>A polymorphism in both Asians and mixed populations. When further analyzed by periodontitis type, only the IL-10 -592C>A polymorphism was associated with CP risk, but not AgP; and the IL-10 -1082A>G and -819C>T polymorphisms have not positive association neither in the CP and AgP.

CONCLUSIONS

The current meta-analysis showed that the IL-10 -592C>A polymorphism was statistically associated with periodontitis risk in the overall population. Moreover, the IL-10 -1082A>G, IL-10 -819C>T, and IL-10 -592C>A polymorphisms were associated with periodontitis risk by ethnicity. Therefore, the IL-10 polymorphisms are of high clinical relevance by ethnicity and would be a useful marker to identify patients who are at higher risk for periodontitis.

Periodontal health and disease: The contribution of genetics

Periodontitis is an infectious, inflammatory disease that is associated with a complex interplay between specific bacteria, host response, and environmental factors. Because of its high degree of familial aggregation, specifically for the more aggressive forms of the disease, genetics factors have been implicated in disease pathogenesis for several decades. This review provides an overview of what we currently know regarding the genetic and epigenetic contributions to periodontal disease and discusses future opportunities in the field.

Could Vitamin D influence risk for Periodontal Disease - to "D" or not to "D"?

PURPOSE OF REVIEW

The purpose of this review is to discuss the literature on associations between vitamin D and periodontal disease, including its strengths and weaknesses. Future direction for continued work in this area is provided.

RECENT FINDINGS

Research in cross-sectional cohorts, surveys, and case-control studies provide support for a role of vitamin D in periodontal disease, especially using clinical indicators such as bleeding on probing and clinical attachment loss. However, these studies have a number of limitations. They cannot establish temporality of these associations. Most case-control studies have been limited in sample size and have inconsistent findings. A number of cross-sectional studies are restricted to select populations (e.g., persons with HIV, diabetes, rheumatoid arthritis) limiting extrapolation of findings to the general aging population.Fewer prospective studies have been conducted, and only three have examined associations using a biomarker for vitamin D that reflects exposure from all its sources (sunlight, diet and supplements). One study is limited by using self-reported measures of disease outcomes, and only two used measures of alveolar crestal height. However, of the prospective studies published, there is a suggestion that vitamin D might prevent against tooth loss. Only two randomized controlled trials have examined these associations, and they support the effects of vitamin D supplementation on prevention of tooth loss and gingival bleeding.

SUMMARY

We strongly suggest that new research should focus on prospective study designs with followup of participants longer than a decade and long-term clinical trials. Such studies should incorporate measures of alveolar bone loss and tooth loss with indication for reason for tooth loss. Such clinical trials should be designed to examine both the influence of vitamin D supplementation alone as well as with other nutrients (e.g., calcium) or therapeutic medications (e.g., bisphosphonates). Currently, there is no strong evidence to suggest that vitamin D protects against development of periodontal disease.

Association between interleukin-10 gene polymorphisms and severe chronic periodontitis

OBJECTIVE

Periodontitis is an inflammatory disease that is a result of the interaction between pathogenic bacteria and host immune response. Genetic alterations in interleukin-10 (IL-10) gene may be associated with the increased risk of periodontitis. We investigated the association between genotype and haplotype frequencies of IL-10 gene polymorphisms and susceptibility to periodontitis in an Iranian population.

METHODS

In this case-control study, a total of 64 patients with periodontitis and 128 healthy subjects were recruited. The PCR-RFLP technique was used to detect IL-10 promoter genotypes at the positions of -1082 (G/A), -819 (C/T), and -592 (C/A) in association with the susceptibility to severe chronic periodontitis.

RESULTS

Regarding IL-10 -592 (C/A) and IL-10 -819 (C/T) alleles and genotypes, no significant association was observed between the risk of periodontitis and genotype frequencies. However, the frequency of GG genotype in IL-10 -1082 (G/A) polymorphic region was higher in normal subjects and was associated with the decreased risk of periodontitis under recessive model [OR = 2.89, 95% CI (0.99-8.43), p = 0.039]. Haplotype analysis revealed a significantly higher presence of H7 (AGC; -592/-1082/-819) [OR = 97.74, 95% CI (95.52-99.96), p < 0.0001].

CONCLUSION

IL-10 -1082(G/A) polymorphism and AGC (-592/-1082/-819) haplotype could be associated with the susceptibility to chronic periodontitis.

Association of interleukin-10-1082 (-1087) A > G polymorphisms and periodontitis risk: An updated meta-analysis based on 26 case-control studies

BACKGROUND

The association between interleukin-10 (IL-10)-1082 (-1087) A > G polymorphism and either chronic (CP) or aggressive periodontitis (AgP) susceptibility was conflicting. This meta-analysis aimed to quantitatively estimate the association.

METHODS

Pubmed, Embase, Web of Science, and WANFAN databases were searched for relevant studies that were submitted prior to January 31, 2018, and meta-analyses were performed using STATA 14.0.

RESULTS

Database mining yielded 26 studies of interest. For the IL-10-1082 (-1087) A > G (rs1800896) polymorphism and its relation to CP susceptibility, the overall analysis showed no significant estimates, but subgroup analysis revealed significant associations in the AA versus GG + GA model in the Caucasian population (odds ratio [OR] = 1.274, 95% confidence interval [CI] = 1.069-1.518, P = 0.007; I²  = 0.0%, P = 0.483) and in the GG versus AA + AG model in the Han population (OR = 6.66, 95% CI = 7.72-9.41, P = 0.000; I²  = 0.0%, P = 0.82), which all showed no obvious publication bias by Egger's linear regression test. For the association between an IL-10-1082 (-1087) A > G polymorphism and AgP susceptibility, the overall analysis and Caucasian subgroup analysis yielded nonsignificant estimates.

CONCLUSIONS

Our meta-analysis indicated that the IL-10-1082 (-1087) AA genotype in the Caucasian population, and the GG genotype in the Han population might be putative risk factors for CP.

PRACTICAL IMPLICATIONS

The IL-10-1082 (-1087) AA genotype and the GG genotype might be potential biomarkers for Caucasian CP and for Han CP, respectively. However, additional research will be required to validate the findings of this meta-analysis.

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.

Interleukin-10 polymorphisms (rs1800871, rs1800872 and rs1800896) and periodontitis risk: A meta-analysis

OBJECTIVE

The objective of this meta-analysis was to assess the association between three interleukin-10 (IL-10) promoter single nucleotide polymorphisms (rs1800871, rs1800872, and rs1800896) and periodontitis risk.

METHODS

A systematic search was conducted in PubMed, Embase, and China National Knowledge Infrastructure databases and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed.

RESULTS

Twenty-six studies met the inclusion criteria. The pooled analysis showed that rs1800871 was associated with an increased periodontitis risk under dominant model (CT + TT vs. CC: p = 0.004, OR = 1.79, 95% CI: 1.21-2.65) in Latin American populations but not in Asian (CT + TT vs. CC: p = 0.229, OR = 0.81, 95% CI: 0.58-1.14) and Caucasian (CT + TT vs. CC: p = 0.910, OR = 1.02, 95% CI: 0.75-1.39) populations. Similarly, rs1800872 conferred an increased risk of periodontitis only in Latin American populations (CA + AA vs. CC: p = 0.012, OR = 2.32, 95% CI: 1.20-4.47; A allele vs. C allele: p = 0.001, OR = 1.61, 95% CI: 1.22-2.14). No significant association was observed between rs1800896 and periodontitis risk. Subgrouping data according to periodontitis type revealed that rs1800872 was associated with both chronic periodontitis (A allele vs. C allele: p = 0.011, OR = 1.72, 95% CI: 1.13-2.62) and aggressive periodontitis (A allele vs. C allele: p = 0.038, OR = 1.32, 95% CI: 1.02-1.72).

CONCLUSION

The studies reviewed support that the IL-10 rs1800871 and rs1800872 polymorphisms may represent a potential genetic biomarker for periodontitis risk in Latin American populations.

The role of three interleukin 10 gene polymorphisms (- 1082 A > G, - 819 C > T, - 592 A > C) in the risk of chronic and aggressive periodontitis: a meta-analysis and trial sequential analysis

Background

Periodontitis is a major oral health problem and it is considered as one of the reasons for tooth loss in developing and developed nations. The objective of the current review was to investigate the association between IL10 polymorphisms − 1082 A > G (rs1800896), -819C > T (rs1800871), − 592 A > C (rs1800872) and the risk of either chronic periodontitis or aggressive periodontitis.

Methods

This is a meta- analysis study, following the preferred reporting items for systematic reviews and meta- analyses (PRISMA). Relevant studies were searched in the health related electronic databases. Methodological quality of the included studies were assessed using the Newcastle-Ottawa Scale. For individual studies, odds ratio (OR) and its 95%confidence interval (CI) were calculated to assess the strength of association between IL10 polymorphisms (− 1082 A > G, -819C > T, − 592 A > C) and the risk of periodontitis. For pooling of the estimates across studies included, the summary OR and its 95% CIs were calculated with random-effects model. The pooled estimates were done under four genetic models such as the allelic contrast model, the recessive model, the dominant model and the additive model. Trial sequential analysis (TSA) was done for estimation of the required information size for this meta-analysis study.

Results

Sixteen studies were identified for this review. The included studies were assessed to be of moderate to good methodological quality. A significant association between polymorphism of IL10–1082 A > G polymorphism and the risk of chronic periodontitis in the non-Asian populations was observed only in the recessive model (OR,1.42; 95% CI:1.11, 1.8,I²: 43%). The significant associations between − 592 A > C polymorphism and the risk of aggressive periodontitis in the non-Asian populations were observed in particular genetic models such as allele contrast (OR, 4.34; 95%CI:1.87,10.07,I²: 65%) and recessive models (OR, 2.1; 95% CI:1.16, 3.82,I²: 0%). The TSA plot revealed that the required information size for evidence of effect was sufficient to draw a conclusion.

Conclusions

This meta-analysis suggested that the IL10–1082 A > G polymorphism was associated with chronic periodontitis CP risk in non-Asians. Thus, in order to further establish the associations between IL10 (− 819 C > T, − 592 A > C) in Asian populations, future studies should include larger sample sizes with multi-ethnic groups.

Electronic supplementary material

The online version of this article (10.1186/s12903-018-0637-9) contains supplementary material, which is available to authorized users.

Contribution of Interleukin-10-592 (-590, -597) C>A Polymorphisms to Periodontitis Susceptibility: An Updated Meta-Analysis Based on 18 Case-Control Studies

Introduction

The association between interleukin-10- (IL-10-) 592 (-590, -597) C>A polymorphisms and susceptibility to chronic or aggressive periodontitis (CP or AgP) is conflicting. This meta-analysis is aimed at quantitatively estimating the association.

Materials and Methods

PubMed, Embase, Web of Science, and WANFAN were searched for studies performed prior to January 31, 2018, to collect data for our research. Meta-analysis was performed using RevMan 5.3 or STATA 14.0.

Results

In total, 18 studies that met our criteria were included. Overall or HWE subgroup analysis of individuals with this polymorphism revealed that in terms of CP susceptibility, there was a significant difference between case groups and control groups in the A allele versus C allele model (OR = 1.38, 95% CI = 1.17–1.64 or OR = 1.38, 95% CI = 1.12–1.70), in the AA versus CC+CA model (OR = 1.49, 95% CI =1.06–2.10 or OR = 1.42, 95% CI = 1.13–1.78), and in the CC versus CA+AA model (OR = 0.69, 95% CI = 0.51–0.92 or OR = 0.68, 95% CI = 0.49–0.93); subgroup analysis based on a nonsmoking population also displayed significance in the A allele versus C allele model (OR = 1.43, 95% CI = 1.15–1.79) and CC versus CA+AA model (OR = 0.62, 95% CI = 0.44–0.87). For this polymorphisms and AgP susceptibility, our analyses revealed a significant association in both the A allele versus C allele model (OR = 1.29, 95% CI = 1.01–1.63) and the AA versus CC+CA model (OR = 1.93, 95% CI = 1.30–2.89); subgroup analysis based on Caucasian or nonsmoking populations showed significant differences in the AA versus CC+CA model (OR = 6.29, 95% CI = 1.78–22.21 or OR = 3.24, 95% CI = 1.59–6.61).

Conclusions

IL-10-592 (-590, -597) A allele and the associated AA genotype may be risk factors for the onset of CP or AgP—particularly for the AA genotype and the increased risk of AgP in Caucasian or nonsmoking populations. Conversely, the CC genotype may act as a protective factor against the onset of CP.

Host genetics role in the pathogenesis of periodontal disease and caries

BACKGROUND

This study aimed to produce the latest summary of the evidence for association of host genetic variants contributing to both periodontal diseases and caries.

MATERIALS AND METHODS

Two systematic searches of the literature were conducted in Ovid Medline, Embase, LILACS and Cochrane Library for large candidate gene studies (CGS), systematic reviews and genome-wide association studies reporting data on host genetic variants and presence of periodontal disease and caries.

RESULTS

A total of 124 studies were included in the review (59 for the periodontitis outcome and 65 for the caries outcome), from an initial search of 15,487 titles. Gene variants associated with periodontitis were categorized based on strength of evidence and then compared with gene variants associated with caries. Several gene variants showed moderate to strong evidence of association with periodontitis, although none of them had also been associated with the caries trait.

CONCLUSIONS

Despite some potential aetiopathogenic similarities between periodontitis and caries, no genetic variants to date have clearly been associated with both diseases. Further studies or comparisons across studies with large sample size and clear phenotype definition could shed light into possible shared genetic risk factors for caries and periodontitis.

Interleukin-10 polymorphisms affect the key periodontal pathogens in Chinese periodontitis patients

Interleukin-10 (IL-10) polymorphisms have been shown to affect IL-10 production. This study investigated the influences of IL-10 polymorphisms on the susceptibility to chronic periodontitis (CP) and aggressive periodontitis (AP), and their possible role in the quantity of subgingival bacteria Aggregatibacter Actinomycetemcomitans and Porphyromonas gingivalis. 92 CP patients, 83 AP patients and 91 periodontal healthy controls were recruited. Serum IL-10 concentration was analyzed by enzyme-linked immunosorbent assay (ELISA). Gene polymorphisms were determined by multiplex SNaPshot technique. Bacteria were quantified by real-time polymerase chain reaction with TaqMan MGB probes. Taking into account age, gender and periodontal status, IL-10-592 AA, -819 TT and ATA/ATA genotype occurred more frequently in patients with CP than in healthy controls. In CP cases, higher quantity of subgingival A. actinomycetemcomitans and lower serum IL-10 levels could be detected in homozygous ATA/ATA carriers. These findings indicate that variants in IL-10 promoter gene were not only associated with predisposition to chronic periodontitis but also affected the subgingival number of A. Actinomycetemcomitans in a Chinese Han population.

Comprehensive analysis of interleukin-8 gene polymorphisms and periodontitis susceptibility

Background

Associations between interleukin-8 (IL-8) gene polymorphisms and periodontitis susceptibility have been investigated in many published studies, but the conclusions are still inconsistent. Therefore, we performed this systematic review and meta-analysis to review which polymorphisms have been researched and to obtain a precise result of the same polymorphism from different studies.

Results

Finally 10 publications involving 1938 patients and 1569 controls were yielded, including 12 polymorphisms. Six studies investigated rs4073 polymorphism; two focused on rs2227306 and rs2227307; two referred to rs2227532 and T-738A; one detected rs2230054, rs1126579 and rs1126580; one inspected A2767T, T₁1722T₂ and C1633T, and one for rs2234671 polymorphism. Of them, IL-8 C1633T and rs1126580 polymorphisms showed positive association while the other ten polymorphisms revealed negative results.

Materials and methods

A comprehensive literature search from PubMed, Web of Science, and Chinese National Knowledge Infrastructure was conducted for all potentially relevant studies published before January 2, 2017. Two authors selected the studies and extracted data. The pooled analysis was conducted using the RevMan 5.1 software if a polymorphism was reported by two or more studies.

Conclusions

Based on current evidence, the IL-8 rs4073, A2767T, T₁1722T₂, rs2234671, rs2230054, rs1126579, rs2227306, rs2227307, rs2227532, and T-738A polymorphisms were not associated with periodontitis susceptibility; the IL-8 C1633T and rs1126580 polymorphisms were associated with increased risk of periodontitis.

Interleukin-1β rs1143627 polymorphism with susceptibility to periodontal disease

Association between interleukin-1 beta (IL-1β) rs1143627 polymorphism and periodontal disease susceptibility was inconsistent; hence we performed this meta-analysis to explore the precise correlation between them. The degree of association was appraised through calculating pooled odds ratio (OR) and its 95% confidence interval (CI). The databases known as PubMed, Embase, and Chinese National Knowledge Infrastructure were searched up to October 26, 2016. A total of 8 eligible case-control studies were finally included, which involved 229 aggressive periodontitis patients, 382 chronic periodontitis patients, and 555 healthy controls. All the five genetic models revealed a non-significant association between IL-1β rs1143627 polymorphism and periodontal disease susceptibility (TT vs. CC: OR = 1.22, 95% CI = 0.80-1.87; CT+TT vs. CC: OR = 0.66, 95% CI = 0.44-1.01; TT vs. CT + CC: OR = 1.19, 95% CI = 0.81-1.74; T vs. C: OR = 0.92, 95% CI = 0.81-1.12; CT vs. CC: OR = 0.92, 95% CI = 0.69-1.23). Sensitivity analyses indicated that the results were robust and the subgroup analyses reached similar conclusions. IL-1β rs1143627 polymorphism is not related to periodontal disease susceptibility in the overall population based on the current evidence, but further studies are required in more large scale sample size with risk factor adjusted.

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.

Genetic Factors and the Risk of Periodontitis Development: Findings from a Systematic Review Composed of 13 Studies of Meta-Analysis with 71,531 Participants

Purpose. This work aimed to synthesize the results of recent meta-analysis focusing on polymorphism in inflammatory mediators and its relation with the risk of periodontitis development. Materials and Methods. A systematic search was conducted using databases for publications prior to October 2016. Three examiners extracted data from articles with a clear association between polymorphisms in the inflammatory mediator gene and the development of periodontitis through meta-analysis using the fixed or randomized statistical models to calculate the Odds Ratio with values of P < 0.05 considered significant. Results. A total of 13 meta-analysis articles with 25 polymorphisms in seven interleukins (IL-1A, IL-1B, IL-4, IL-6, IL-8, IL-10, and IL-18), three cellular receptors (Fcγ receptors: FCGR2A, FCGR3A, and FCGR3B), and five inflammatory mediators (COX-2, MMP-2, MMP-3, MMP-8, and MMP-9), with a total of 71,531 participants, approaching different classifications of the disease. Conclusion. The study demonstrated that polymorphisms in the IL-1A, IL-1B, IL-6, IL-10, MMP-3 (chronic form), and MMP-9 (chronic form) polymorphisms were significantly associated with the risk of developing periodontitis, whereas other polymorphisms in the IL-4, IL-8, IL-18, Fcγ, COX-2, MMP-2, MMP-3 (aggressive), MMP-8, and MMP-9 (aggressive) polymorphisms had no significant association with risk of developing periodontitis.

Single nucleotide polymorphism at -1087 locus of interleukin-10 gene promoter is associated with severe chronic periodontitis in nonsmoking patients

OBJECTIVE

Single nucleotide polymorphisms (SNPs) in the promoter region of interleukin (IL)-10 gene, which codes for the anti-inflammatory cytokine IL-10, have been associated with its level of production in chronic periodontitis. The prevalence of promoter SNP genotypes is known in other populations with chronic periodontitis, while its association in the Indian population is not known. Hence, the present study was designed to investigate the prevalence of IL-10 promoter polymorphism in a racially defined group of Indians with severe chronic periodontitis as the Indian population is known to be genetically diverse.

MATERIALS AND METHODS

Genomic deoxyribonucleic acid was extracted from 46 nonsmoking patients with severe chronic periodontitis and 45 subjects with healthy periodontium. A SNP locus at -1087 of IL-10 was chosen, as this locus has been frequently associated with chronic periodontitis in other population. Genotyping was carried out using allele-specific polymerase chain reaction (AS-PCR), and the frequencies of genotype were analyzed between the groups.

RESULTS

The distribution of genotype and allele frequencies showed significant differences between the study groups. The prevalence of genotype AA alleles at -1087 locus of IL-10 was significantly higher in severe chronic periodontitis patients compared to the healthy controls (P = 0.05).

CONCLUSION

The study has identified a positive association between the occurrence of AA allele at -1087 locus of IL-10 gene and severe chronic periodontitis in nonsmoking patients.

Polymorphisms in the interleukin-10 gene and chronic periodontitis in patients with atherosclerotic and aortic aneurysmal vascular diseases

Background

Chronic periodontitis (CP), atherosclerotic and aortic aneurysmal vascular diseases (VD) are chronic inflammatory conditions with multifactorial etiologies, including involvement of predisposing genetic factors. In a previous study, polymorphisms in the gene for the anti-inflammatory interleukin-1 receptor antagonist were associated with CP in patients with VD.

Objective

This study investigates whether polymorphisms in the gene for the anti-inflammatory interleukin-10 (IL10) could be related to CP in the same manner.

Methods

Seventy-two patients with VD of whom 35 had CP were genotyped for single nucleotide polymorphisms (SNPs) in the IL10 −592 (rs1800872), −819 (rs1800871), and −1,082 (rs1800896) gene by Taqman rtPCR method and by DNA sequencing.

Results

The C alleles and C/C genotypes of IL10 −592 and IL10 −819 frequencies were significantly higher, while the frequencies of the IL10 −592 (C/A) and IL10 −819 (C/T) heterozygote genotypes were significantly lower in the VD group with CP compared to those without CP. The IL10 haplotype ATA frequency (−1,082, −819, −592) showed a trend to a significant difference between the two groups indicating protection against CP.

Conclusions

Taken together, our findings suggest an independent association of genetic polymorphisms in the IL-10 gene locus with CP in patients with VD. Development of CP and the implications on vascular disease emphasize the importance of early detection and adequate treatment of periodontitis among these patients.

Brain-derived neurotrophic factor in chronic periodontitis

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophic factor family. Outside the nervous system, BDNF has been shown to be expressed in various nonneural tissues, such as periodontal ligament, dental pulp, and odontoblasts. Although a role for BDNF in periodontal regeneration has been suggested, a function for BDNF in periodontal disease has not yet been studied. The aim of this study was to analyze the BDNF levels in periodontal tissues of patients with chronic periodontitis (CP) and periodontally healthy controls (HC). All subjects were genotyped for the rs4923463 and rs6265 BDNF polymorphisms. Periodontal tissues were collected for ELISA, myeloperoxidase (MPO), and microscopic analysis from 28 CP patients and 29 HC subjects. BDNF levels were increased in CP patients compared to HC subjects. A negative correlation was observed when analyzing concentration of BDNF and IL-10 in inflamed periodontium. No differences in frequencies of BDNF genotypes between CP and HC subjects were observed. However, BDNF genotype GG was associated with increased levels of BDNF, TNF-α, and CXCL10 in CP patients. In conclusion, BDNF seems to be associated with periodontal disease process, but the specific role of BDNF still needs to be clarified.

Association of interleukin-1 gene variations with moderate to severe chronic periodontitis in multiple ethnicities

Background and Objective

Genetic markers associated with disease are often non-functional and generally tag one or more functional “causative” variants in linkage disequilibrium. Markers may not show tight linkage to the causative variants across multiple ethnicities due to evolutionary divergence, and therefore may not be informative across different population groups. Validated markers of disease suggest causative variants exist in the gene and, if the causative variants can be identified, it is reasonable to hypothesize that such variants will be informative across diverse populations. The aim of this study was to test that hypothesis using functional Interleukin-1 (IL-1) gene variations across multiple ethnic populations to replace the non-functional markers originally associated with chronic adult periodontitis in Caucasians.

Material and Methods

Adult chronic periodontitis cases and controls from four ethnic groups (Caucasians, African Americans, Hispanics and Asians) were recruited in the USA, Chile and China. Genotypes of IL1B gene single nucleotide polymorphisms (SNPs), including three functional SNPs (rs16944, rs1143623, rs4848306) in the promoter and one intronic SNP (rs1143633), were determined using a single base extension method or TaqMan 5′ nuclease assay. Logistic regression and other statistical analyses were used to examine the association between moderate to severe periodontitis and IL1B gene variations, including SNPs, haplotypes and composite genotypes. Genotype patterns associated with disease in the discovery study were then evaluated in independent validation studies.

Results

Significant associations were identified in the discovery study, consisting of Caucasians and African Americans, between moderate to severe adult chronic periodontitis and functional variations in the IL1B gene, including a pattern of four IL1B SNPs (OR = 1.87, p < 0.0001). The association between the disease and this IL1B composite genotype pattern was validated in two additional studies consisting of Hispanics (OR = 1.95, p = 0.04) or Asians (OR = 3.27, p = 0.01). A meta-analysis of the three populations supported the association between the IL-1 genotype pattern and moderate to severe periodontitis (OR 1.95; p < 0.001). Our analysis also demonstrated that IL1B gene variations had added value to conventional risk factors in predicting chronic periodontitis.

Conclusion

This study validated the influence of IL-1 genetic factors on the severity of chronic periodontitis in four different ethnicities.

Interleukin-10 inhibits bone resorption: a potential therapeutic strategy in periodontitis and other bone loss diseases

Periodontitis and other bone loss diseases, decreasing bone volume and strength, have a significant impact on millions of people with the risk of tooth loss and bone fracture. The integrity and strength of bone are maintained through the balance between bone resorption and bone formation by osteoclasts and osteoblasts, respectively, so the loss of bone results from the disruption of such balance due to increased resorption or/and decreased formation of bone. The goal of therapies for diseases of bone loss is to reduce bone loss, improve bone formation, and then keep healthy bone density. Current therapies have mostly relied on long-term medication, exercise, anti-inflammatory therapies, and changing of the life style. However there are some limitations for some patients in the effective treatments for bone loss diseases because of the complexity of bone loss. Interleukin-10 (IL-10) is a potent anti-inflammatory cytokine, and recent studies have indicated that IL-10 can contribute to the maintenance of bone mass through inhibition of osteoclastic bone resorption and regulation of osteoblastic bone formation. This paper will provide a brief overview of the role of IL-10 in bone loss diseases and discuss the possibility of IL-10 adoption in therapy of bone loss diseases therapy.

Association Analysis of IL10, TNF-α, and IL23R-IL12RB2 SNPs with Behçet's Disease Risk in Western Algeria

Objective: We have conducted the first study of the association of interleukin (IL)-10, tumor necrosis factor alpha (TNF-α), and IL23R-IL12RB2 region single nucleotide polymorphisms (SNPs) with Behçet’s disease (BD) in Western Algeria.

Methods: A total of 51 BD patients and 96 unrelated controls from West region of Algeria were genotyped by direct sequencing for 11 SNPs including 2 SNPs from the IL10 promoter [c.-819T > C (rs1800871), c.-592A > C (rs1800872)], 6 SNPs from the TNF-α promoter [c.-1211T > C (rs1799964), c.-1043C > A (rs1800630), c.-1037C > T (rs1799724), c.-556G > A (rs1800750), c.-488G > A (rs1800629), and c.-418G > A (rs361525)], and 3 SNPs from the IL23R-IL12RB2 region [g.67747415A > C (rs12119179), g.67740092G > A (rs11209032), and g.67760140T > C (rs924080)].

Results: The minor alleles c.-819T and c.-592A were significantly associated with BD [odds ratio (OR) = 2.18; 95% confidence interval (CI) 1.28–3.73, p = 0.003]; whereas, there was weaker association between TNF-α promoter SNPs or IL23R-IL12RB2 region and disease risk.

Conclusion: Unlike the TNF-α and the IL23R-IL12RB2 region SNPs, the two IL10 SNPs were strongly associated with BD. The -819T, and -592A alleles and the -819TT, -819CT, and -592AA and -592CA genotypes seem to be highly involved in the risk of developing of BD in the population of Western Algeria.

Clinical outcomes of periodontal therapy are not influenced by the ATC/TTC haplotype in the IL8 gene

BACKGROUND AND OBJECTIVE

Although chronic periodontitis (CP) is a multifactorial condition, few studies have investigated the potential association of gene variants with the outcome of periodontal therapy. In a previous study, we reported that variants in the interleukin-8 (IL8) gene were associated with CP in a Brazilian population. The aim of this nonrandomized study was to investigate whether genetic susceptibility to CP, conferred by the presence of the IL8 ATC/TTC haplotype, influences the clinical outcomes of nonsurgical periodontal therapy and the IL-8 protein levels in the gingival crevicular fluid.

MATERIAL AND METHODS

Forty-one individuals were grouped according to the presence (susceptible to CP; n = 21) or absence (not susceptible to CP; n = 20) of the IL8 ATC/TTC haplotype. These individuals received nonsurgical periodontal therapy from one periodontist, who was blinded to the genetic status of each patient, and follow up continued for 45 d. The clinical parameters and gingival crevicular fluid samples were collected at baseline and on day 45. The IL-8 levels were determined by an ELISA. The data were subjected to the Mann-Whitney U-test, Wilcoxon and Spearman tests and to multiple logistic-regression analysis.

RESULTS

No significant differences between patients with or without the IL8 ATC/TTC haplotype were found for the outcome of nonsurgical periodontal therapy and IL-8 levels. The multiple logistic-regression analysis did not show a statistically significant association between the IL8 haplotype and the variables studied.

CONCLUSION

In this longitudinal clinical study, we observed that neither the outcome of nonsurgical periodontal therapy nor the IL-8 levels were influenced by the IL8 ATC/TTC CP-susceptibility haplotype. Additional studies of CP patients from other ethnic populations are necessary to confirm these results.

Inflammatory mediators in the pathogenesis of periodontitis

Periodontitis is a chronic inflammatory condition of the periodontium involving interactions between bacterial products, numerous cell populations and inflammatory mediators. It is generally accepted that periodontitis is initiated by complex and diverse microbial biofilms which form on the teeth, i.e. dental plaque. Substances released from this biofilm such as lipopolysaccharides, antigens and other virulence factors, gain access to the gingival tissue and initiate an inflammatory and immune response, leading to the activation of host defence cells. As a result of cellular activation, inflammatory mediators, including cytokines, chemokines, arachidonic acid metabolites and proteolytic enzymes collectively contribute to tissue destruction and bone resorption. This review summarises recent studies on the pathogenesis of periodontitis, with the main focus on inflammatory mediators and their role in periodontal disease.

Mathematical modeling suggests that periodontitis behaves as a non-linear chaotic dynamical process

BACKGROUND

This study aims to expand on a previously presented cellular automata model and further explore the non-linear dynamics of periodontitis. Additionally the authors investigated whether their mathematical model could predict the two known types of periodontitis, aggressive (AgP) and chronic periodontitis (CP).

METHODS

The time evolution of periodontitis was modeled by an iterative function, based on the hypothesis that the host immune response level determines the rate of periodontitis progression. The chaotic properties of this function were investigated by direct iteration, and the model was validated by immunologic and clinical parameters derived from two clinical study populations.

RESULTS

Periodontitis can be described as chaos with the level of the host immune response determining its progression rate; the dynamics of the proposed model suggest that by increasing the host immune response level, periodontitis progression rate decreases. Renormalization transformations show the presence of two overlapping zones of disease activity corresponding to AgP and CP. By k-means cluster analysis, immunologic parameters corroborated the findings of the renormalization transformations. Periodontitis progression rates are modeled to scale with a power law of 1.3, and the mean exponential speed of the system is found to be 1.85 (metric entropy); clinical datasets confirmed the mathematical estimates.

CONCLUSIONS

This study introduces a mathematical model that identifies periodontitis as a non-linear chaotic process. It offers a quantitative assessment of the disease progression rate and identifies two zones of disease activity that correspond to the existing classification of periodontitis in the AgP and CP types.