Association analysis between interleukin-1 family polymorphisms and generalized aggressive periodontitis in a Chinese population

Single Nucleotide Polymorphisms in IL-1A RS1800587, IL-1B RS1143634 and Vitamin D Receptor Rs731236 in Stage III Grade B/C Periodontitis

The purpose of the study is to determine the prevalence of interleukin (IL)-1A (rs1800587), IL-1B (rs1143634) and vitamin D receptor (VDR) (TaqI, rs731236) gene polymorphisms in the Turkish population and their association with Stage III Grade B/C periodontitis. Systemically and periodontally healthy individuals (N = 100) and Stage III Grade B/C periodontitis patients (N=100) based on clinical and radiographic examination were included in this research. Clinical attachment level, probing depth, bleeding on probing, plaque and gingival indices of the subjects were measured. Genotyping of IL-1A (rs1800587), IL-1B (rs1143634) and VDR (rs731236) polymorphisms was conducted by Real Time PCR. Allelic and genotypic distributions of IL-1A (rs1800587) gene polymorphism were not associated with periodontitis (p>0.05). In IL-1B (rs1143634) gene polymorphism, the C allele was detected more frequently in healthy individuals compared with the periodontitis patients (p=0.045). CC genotype and C allele in VDR (rs731236) gene polymorphism was higher in periodontitis patients (p=0.031, p=0.034, respectively). In comparison with Grade B periodontitis patients and healthy subjects, CC genotype and C allele were observed more frequently in the Grade B periodontitis in terms of alleles (C/T) and genotypes for VDR (rs731236) polymorphism (p=0.024, p=0.008, respectively). This study presents that the VDR (rs731236) polymorphism are associated with enhanced susceptibility to Stage III periodontitis in the Turkish population. Furthermore, VDR (rs731236) polymorphism may be used as an identification criteria to discriminate Grade B and Grade C in Stage III periodontitis.

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.

Personalized periodontal treatment for the tobacco- and alcohol-using patient

The use of various forms of tobacco is one of the most important preventable risk factors for the incidence and progression of periodontal disease. Tobacco use negatively affects treatment outcomes for both periodontal diseases and conditions, and for dental implants. Tobacco-cessation programs can mitigate these adverse dental treatment outcomes and may be the most effective component of a personalized periodontal treatment approach. In addition, heavy alcohol consumption may exacerbate the adverse effects of tobacco use. In this review, the microbiology, host/inflammatory responses and genetic characteristics of the tobacco-using patient are presented as a framework to aid the practitioner in developing personalized treatment strategies for these patients. These personalized approaches can be used for patients who use a variety of tobacco products, including cigarettes, cigars, pipes, smokeless tobacco products, e-cigarettes and other tobacco forms, as well as patients who consume large amounts of alcohol. In addition, principles for developing personalized tobacco-cessation programs, using both traditional and newer motivational and pharmacological approaches, are presented.

Clinical performance of non-surgical periodontal therapy in a large Chinese population with generalized aggressive periodontitis

AIM

This study aimed to evaluate clinical performance of non-surgical periodontal treatment (NSPT) and its influential factors in a large Chinese population with generalized aggressive periodontitis (GAgP).

MATERIAL AND METHODS

Longitudinal periodontal examination data of 1,004 GAgP patients (numbers of patients with observation periods 6 weeks~, 3 months~, 6 months~, 1 year~, 3 years~ and >5 years were 203, 310, 193, 205, 70 and 23, respectively) were extracted from a hospital-based electronic periodontal charting record system and analysed by multilevel analysis.

RESULTS

Mean probing depth (PD) and attachment loss (AL) reductions at patient level were 1.17 mm and 1.07 mm, respectively. Multilevel analysis demonstrated PD reductions after maintenance were mainly influenced by frequency of supportive periodontal treatment (FSPT), gender, adjunctive systemic use of antibiotics, baseline mobility, tooth type and baseline PD and bleeding index reductions were mainly influenced by FSPT, adjunctive systemic use of antibiotics, baseline AL, baseline mobility, tooth type and baseline PD.

CONCLUSION

The clinical performance of NSPT on patients with GAgP was proved in the large Chinese population. Outcomes of NSPT were mainly influenced by FSPT, adjunctive systemic use of antibiotics, baseline mobility, tooth type and baseline PD.

Application of Interleukin-1 Genes and Proteins to Monitor the Status of Chronic Periodontitis

It has been widely reported that periodontitis may lead to bone tissue and teeth loss and result in failure of prosthodontics or implants. Interleukin-1 (IL-1) is a potent proinflammatory cytokine that plays an essential role during the pathogenesis of periodontitis. However, the gene polymorphisms of IL-1α, IL-1β and IL-1RN and the relationship between these protein expressions in healthy people and patients with chronic periodontitis (CP) in China have not been fully elucidated. We investigated the gene polymorphisms and protein expression of IL-1α, IL-1β and IL-1RN in healthy subjects and CP patients, and our data suggest that these gene polymorphisms are associated with CP. The frequency of the C/C genotype of IL-1α was 55% in CP patients, while in the control group it was 20% (p<0.0001). The C/C genotype of IL-1β was also higher in CP patients (51%) than in controls (21%) (p<0.0001). For the 2/2 genotype of IL-1RN, CP patients showed a 30% frequency, while in controls this was 15% (p<0.0001). Protein levels evaluated by enzyme-linked immunosorbent assay demonstrated a significant difference in secretion between patients and controls for IL-1α and IL-1β. These results indicate that genotype and protein production of IL-1α, IL-1β and IL-1RN are associated with CP in a Chinese population, and might be putative risk indicators for chronic periodontitis.

Association of cytokines polymorphisms with chronic peridontitis and rheumatoid arthritis in a Mexican population

OBJECTIVE

Historically, it has been shown that rheumatoid arthritis (RA) and periodontitis (PE) share pathophysiological similarities and possibly a genetic background. In order to elucidate the genetic background between both diseases, we evaluated the distributions of five SNPs genotypes and all the possible haplotypes composed in subjects with isolated RA, PE, combined diseases and healthy controls.

MATERIALS AND METHODS

The study population consisted of 280 Mexican subjects. Genomic DNA was isolated from buccal epithelial cells collected by cheek scrapings and analyzed for the determination of the following SNPs: IL-1α + 4845 (rs17561), IL-1α -889 (rs1800587), IL-1β + 3954 (rs1143634), IL-1β -511(rs16944) and TNF-α -308 (rs1800629).

RESULTS

After adjustment for age, sex and smoking status, multiple logistic regression analysis revealed a no significant association in the genotype frequencies of TNF-α -308 and IL-1α + 4845 SNPs. Otherwise a significant association was observed in IL-1β + 3954 and IL-1β -511 (p < 0.05) while IL-1α -889 was of borderline statistical significance (p = 0.054). Also, we found three negative associated haplotypes with PE: IL-1α + 4845 G/IL-1β -511 A, IL-1β + 3954 C/IL-1β -511 A and interestingly IL-1α -889 C/IL-1β -511 A also with a positive association with RA.

CONCLUSIONS

Some genotypes and haplotypes are associated with the diseases. But it seems that the genetic background of the association between RA and PE needs to be explored deeper.

Interaction of IL1B and IL1RN polymorphisms, smoking habit, gender, and ethnicity with aggressive and chronic periodontitis susceptibility

Background:

Although the interleukin-1 (IL-1) plays a critical role in the pathogenesis of periodontitis, associations between IL1 gene cluster polymorphisms and the disease remains unclear.

Aims:

To investigate the importance of IL1B-511C>T (rs16944), IL1B +3954C>T (rs1143634), and IL1RN intron 2 variable number tandem repeat (VNTR) (rs2234663) polymorphisms, individually or in combination, as the risk factors of periodontitis in a Southeastern Brazilian population with a high degree of miscegenation.

Subjects and Methods:

A total of 145 individuals, with aggressive (aggressive periodontitis [AgP], n = 43) and chronic (chronic periodontitis [CP], n = 52) periodontitis, and controls (n = 50) were genotyped by polymerase chain reaction (PCR) (IL1RN intron 2 VNTR) or PCR-restriction fragment length polymorphism (PCR-RFLP) (IL1B-511 C>T and IL1B + 3954C>T) techniques.

Statistical Analysis:

The independent t-test, Chi-square, and Fisher's exact tests were used. The SNPStats program was used for haplotype estimation and multiplicative interaction analyses.

Results:

The IL1B +3954T allele represented risk for CP (odds ratio [OR] = 2.84), particularly in smokers (OR = 4.43) and females (OR = 6.00). The minor alleles IL1RN*2 and *3 increased the risk of AgP (OR = 2.18), especially the IL1RN*2*2 genotype among  white Brazilians (OR = 7.80). Individuals with the combinations of the IL1B + 3954T and IL1RN*2 or *3-containing genotypes were at increased risk of developing CP (OR = 4.50). Considering the three polymorphisms (rs16944, rs1143634, and rs2234663), the haplotypes TC2 and CT1 represented risk for AgP (OR = 3.41) and CP (OR = 6.39), respectively.

Conclusions:

Our data suggest that the IL1B +3954C>T and IL1RN intron 2 VNTR polymorphisms are potential candidates for genetic biomarkers of periodontitis, particularly in specific groups of individuals.

Polymerase chain reaction: A molecular diagnostic tool in periodontology

This review discusses the principles of polymerase chain reaction (PCR) and its application as a diagnostic tool in periodontology. The relevant MEDLINE and PubMed indexed journals were searched manually and electronically by typing PCR, applications of PCR, PCR in periodontics, polymorphism studies in periodontitis, and molecular techniques in periodontology. The searches were limited to articles in English language and the articles describing PCR process and its relation to periodontology were collected and used to prepare a concise review. PCR has now become a standard diagnostic and research tool in periodontology. Various studies reveal that its sensitivity and specificity allow it as a rapid, efficient method of detecting, identifying, and quantifying organism. Different immune and inflammatory markers can be identified at the mRNA expression level, and also the determination of genetic polymorphisms, thus providing the deeper insight into the mechanisms underlying the periodontal disease.

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

Objective. To explore whether GC (group-specific component) rs17467825, rs4588, and rs7041 polymorphisms are associated with generalized aggressive periodontitis. Methods. This case-control study recruited 372 patients with generalized aggressive periodontitis (group AgP) and 133 periodontal healthy subjects (group HP). GC rs17467825, rs4588, and rs7041 genotypes and plasmatic vitamin D-binding protein (DBP) were measured. Analysis of single SNP and multiple SNPs was performed and relevance between plasmatic DBP and haplotypes was analyzed. Results. GC rs17467825 GG genotype was statistically associated with lower risk for generalized aggressive periodontitis under the recessive model (OR = 0.52, 95% CI: 0.30-0.92, p = 0.028). GC rs17467825 and rs4588 had strong linkage disequilibrium with r² ≥ 0.8 and D' ≥ 0.8. Haplotype (GC rs17467825, rs4588) GC was associated with the less risk for generalized aggressive periodontitis (OR = 0.29, 95% CI: 0.09-0.96, p = 0.043). In group AgP, individuals with combined genotype (GC rs17467825, rs4588) AG+CA had significantly lower plasmatic DBP level than those with the other two combined genotypes (AG+CA versus AA+CC p = 0.007; AG+CA versus GG+AA p = 0.026). Conclusions. GC rs17467825 genotype GG and haplotype (GC rs17467825, rs4588) GC are associated with generalized aggressive periodontitis. The association may be acquired through regulating DBP levels. The functions of GC gene and DBP in inflammatory disease need to be further studied.

IL-1B (C+3954T) gene polymorphism and susceptibility to gastric cancer in the Iranian population

BACKGROUND

Gastric cancer as one of the most important diseases affecting health in all worldwide. Current studies have confirmed associations of cytokine gene polymorphisms with the risk of gastric cancer development. The current research aimed to assess the association of IL-1B+3954 genotypes with the risk of gastric cancer in the Iranian population.

MATERIALS AND METHODS

This case-control study covered 49 gastric cancer patients compared to 53 cancer free individuals as a control group. Genomic-DNA extraction was carried out from bioptic samples of patients and peripheral blood of healthy volunteers. Polymorphism of IL-1B +3954 genotypes were analysed with a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

The frequencies of IL-1B +3954 A1A1, A1A2 and A2A2 genotypes in healthy individuals were 26.4, 66 and 7.6 %, respectively. However, in gastric cancer patients, A1A1, A1A2 and A2A2 with 4.1, 51 and 44.9% were observed (p<0.05).

CONCLUSIONS

The findings of our results show a positive association between the IL-1B+3954 genotype distribution and the risk of gastric cancer disease in the Iranian population.

Association between Interleukin-1β Gene -511C>T/+3954C>T Polymorphisms and Aggressive Periodontitis Susceptibility: Evidence from a Meta-Analysis

Background

Interleukin-1β (IL-1β) is an important inflammatory cytokine. The associations between IL-1β gene −511C>T/+3954C>T polymorphisms and aggressive periodontitis (AgP) susceptibility have been conflicting. We therefore conducted a meta-analysis to investigate the association of IL-1β genetic polymorphisms with susceptibility to AgP.

Material/Methods

PubMed and Embase electronic databases were searched for relevant studies. Odds ratios (ORs) with 95% confidence interval (CIs) were used to assess the association between IL-1β polymorphisms and AgP risk. Heterogeneity, publication bias, and sensitivity analysis were performed to guarantee the statistical power.

Results

Twenty published studies involving 965 patients and 1234 control subjects were included. No significant association between IL-1β polymorphisms and AgP was found. For −511C>T (T vs. C: OR=0.966, 95%CI=0.696–1.341, P=0.869; CT vs. CC: OR=0.936, 95%CI=0.761–1.151; TT vs. CC: OR=0.892, 95%CI=0.464–1.715, P=0.719; CT+TT vs. CC: OR=1.026, 95%CI=0.795–1.323; TT vs. CC+CT: OR=0.864, 95%CI=0.436–1.713). For +3954C>T (T vs. C: OR=1.069, 95%CI=0.901–1.268; CT vs. CC: OR=0.921, 95%CI=0.699–1.212; TT vs. CC: OR=1.064, 95%CI=0.747–1.515; CT+TT vs. CC: OR=0.990, 95%CI=0.764–1.283; TT vs. CC+CT: OR=1.229, 95%CI=0.919–1.643). Subgroup analyses were conducted with HWE, ethnicity, and study design, and no significant association was detected.

Conclusions

These results demonstrate that IL-1β −511C>T and +3954C>T polymorphisms are not the risk factors for developing AgP.

Interleukin polymorphisms in aggressive periodontitis: A literature review

Aggressive periodontitis (AgP), occurs in a younger age group (≤35 years) and is associated with the rapid destruction of periodontal attachment and supporting bone. Genetic polymorphisms are allelic variants that occur in at least 1% of the population that could potentially alter the function of the proteins that they encode. Interleukins are a group of cytokines that have complex immunological functions including proliferation, migration, growth and differentiation of cells and play a key role in the immunopathogenesis of periodontal disease. The aim of this review was to summarize the findings of studies that reported associations or potential associations of polymorphisms in the interleukin family of cytokines, specifically with AgP.

Interleukin-1β (3953/4) C→T polymorphism increases the risk of chronic periodontitis in Asians: evidence from a meta-analysis of 20 case-control studies

INTRODUCTION

To investigate the association of the interleukin-1β (IL-1β) (3953/4) C→T polymorphism with chronic periodontitis (CP) in Asians.

MATERIAL AND METHODS

Systematic searches of electronic databases and hand searching of references were performed, including PubMed, Embase, the Cochrane Library, and the Chinese National Knowledge Infrastructure (CNKI). Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the associations. Publication bias was tested by Egger's test. Sensitivity analysis was conducted by limiting the meta-analysis studies conforming to Hardy-Weinberg equilibrium (HWE). Data analyses were carried out using RevMan 6.0.

RESULTS

A meta-analysis was performed on 20 published case-control studies, including 1,656 CP cases and 1,498 healthy controls. The pooled OR was 1.60 (95% CI = 1.02-2.52, p = 0.04) for the T allele carriers (TT + CT) compared with CC and 1.60 (95% CI = 1.06-2.42, p = 0.02) for T vs. C. Subgroup analysis by country revealed significant risks of CP among Indians carrying the T allele (TT vs. CC: OR = 3.88, 95% CI = 1.77-8.50, p = 0.0007).

CONCLUSIONS

The analysis showed that IL-1β (3953/4) C→T polymorphism probably increases the risk of CP in Asians, and the IL-1β+3954 TT genotype may be associated with a strongly increased risk of CP in Indians, but not in Chinese.

Association of interleukin-1 α (-889) gene polymorphism in patients with generalized aggressive and chronic periodontitis

BACKGROUND

There is a strong evidence that genetic as well as environmental factors affect the age of onset, severity and lifetime risk of developing periodontitis. The objective of the present study was to compare and to evaluate the association between interleukin (IL)-1α(-889) and gene polymorphisms in patients with generalized aggressive periodontitis, chronic periodontitis and healthy controls.

MATERIALS AND METHODS

A total of 60 Indian patients, with 20 aggressive periodontitis, 20 chronic periodontitis and 20 healthy controls were recruited for this study. From each patient, a volume of 2 ml of blood was collected by venipuncture in the ante-cubital fossa and was stored in sodium EDTA vacutainers and was used for genotyping assays with the polymerase chain reaction restriction fragment length polymorphism technique. Clinical parameters such as oral hygiene index, gingival index and clinical attachment loss (CAL) were evaluated for each patient. Genotype distribution between different groups were analyzed using Chi-square test. A P = 0.05 or less was set for significance.

RESULTS

The mean oral hygiene index was 3.7 ± 0.86 and 3.25 ± 0.30 for chronic and aggressive periodontitis cases respectively. The CAL was 4.29 ± 0.63 mm for chronic periodontitis and 6.44 ± 0.57 mm for aggressive periodontitis. Homozygous genotype 2,2 was more predominant in cases of aggressive periodontitis whereas in chronic periodontitis, heterozygous genotype 1,2 was more predominant when compared with others (P < 0.001). Odds ratio for aggressive versus chronic periodontitis was calculated as 6.2 (95% confidence interval 6.019-7.892).

CONCLUSION

The results of the present study support a positive association between aggressive periodontitis and the presence of the IL-1α-889, allele 2 polymorphism in Indian patients.

Interleukin-1α -899 (+4845) C→T polymorphism is not associated with aggressive periodontitis susceptibility: A meta-analysis based on 19 case-control studies

A number of published studies investigated the association between interleukin-1α (IL-1α) −899 (+4845) C→T polymorphism and susceptibility to aggressive periodontitis (AgP). However, the results from different studies are controversial. This study was conducted to further investigate the association between IL-1α −899 (+4845) C→T polymorphism and AgP using a meta-analysis. A search was conducted through PubMed up to May 1, 2013 and a total of 19 relevant case-control studies were identified. The results of this meta-analysis demonstrated that IL-1α −899 (+4845) C→T polymorphism is not associated with susceptibility to AgP under allele T vs. C [odds ratio (OR)=1.00, 95% confidence interval (CI): 0.88–1.14, P=0.98; I²=28.86%] or allele A vs. C comparison (OR=0.99, 95% CI: 0.85–1.14, P=0.85; I²=33.66%). The subgroup analyses based on ethnicity, source of controls and Hardy-Weinberg equilibrium (HWE) also revealed no such association. There existed a weak publication bias (Egger’s test P=0.02). In conclusion, based on the currently available evidence, there is no association between IL-1α −899 (+4845) C→T polymorphism and susceptibility to AgP.

Relationship between IL1 gene polymorphisms and periodontal disease in Japanese women

Epidemiological evidence on the relationship between IL1A and/or IL1B polymorphisms and periodontal disease is inconsistent. We investigated associations between three IL1 single-nucleotide polymorphisms (SNPs) in genes encoding interleukin (IL) -1α (rs1800587) and IL-1β (rs1143634 and rs16944) and the risk of periodontal disease among young Japanese women. A case-control study was performed with a total of 1150 women, including 131 subjects who had at least one tooth with a probing pocket depth of 4 mm or deeper and 1019 periodontally healthy controls. Compared with a reference group of women with the GG genotype of SNP rs16944, those with the GA genotype had a significantly reduced risk of periodontal disease, while there was no significant relationship between the AA genotype and periodontal disease. No evident relationships were observed between SNP rs1800587 or rs1143634 and periodontal disease. Our study did not reveal any evidence of interaction between the IL1 polymorphisms and smoking. The results of this study showed that the heterozygous variant genotype of the IL1 rs16944 was significantly associated with a reduced risk of periodontal disease in young Japanese women. Smoking did not significantly modify the gene-disease associations under study.

Analysis of interleukin-1β gene polymorphism and its association with generalized aggressive periodontitis disease

Generalized aggressive periodontitis (GAP) is a subgroup of periodontal diseases among 20-35 years age group adults. Several studies have reported the association of interleukin-1β gene polymorphism with periodontal diseases among different populations. The present study aimed at investigating the presence of IL-1β polymorphism in GAP patients in Iran. Further, the presence of IL-1β(+3954) gene polymorphism was evaluated in the GAP patients (n=26) and healthy individuals (n=26). All three genotypes (A1A1 [56%], A1A2 [28%], and A2A2 [16%]) were observed in healthy individuals, whereas only A1A1 (38.5%) and A2A2 (61.5%) were the genotypes observed in the patients. There was a significant positive association between distribution of IL-1β genotypes and the risk of periodontitis disease (p=0.017). Further, there was a significant positive association between probing pocket depth and IL-1β genotypes of patients (p=0.014). However, no meaningful correlation between genotype-clinical attachment loss and genotype bleeding on probing with the risk of GAP (p=0.418, p=0.819, respectively) was found. In conclusion, findings of the present study demonstrate a positive association between IL-1β gene polymorphism and risk of periodontitis disease.

New attempts to modify periodontal risk assessment for generalized aggressive periodontitis: a retrospective study

BACKGROUND

Periodontal risk assessment (PRA) model was designed for risk evaluation of treated patients with periodontal disease. However, its use on generalized aggressive periodontitis (GAgP) had been scarcely reported. This study aims to investigate the association of original PRA/modified PRA (MPRA) and compliance of periodontal maintenance with long-term treatment outcomes of Chinese patients with GAgP.

METHODS

Eighty-eight patients from a GAgP cohort, who completed active periodontal treatment (APT) and accepted reevaluation 3 to 11 years (mean of 5.5 years) afterward, were enrolled. PRA was modified (three strategies involving replacement of bleeding on probing with bleeding index >2, counting sites with probing depth ≥6 mm and changing method of bone loss [BL] calculation) to classify patients into different risk groups based on data at the first recall after APT. PRA and three MPRA models were investigated regarding long-term association with tooth loss (TL) and alteration of bone level (∆BL).

RESULTS

Based on original PRA, 87 patients (98.8%) had a high-risk profile. According to three MPRA models, annual TL per patient values were greater in high-risk groups than in low-to-moderate risk groups (MPRA-1, 0.20 ± 0.33 versus 0.04 ± 0.14; MPRA-2, 0.18 ± 0.32 versus 0.05 ± 0.14; MPRA-3, 0.17 ± 0.32 versus 0.05 ± 0.15; P <0.05). By MPRA-1, irregular compliers with low-to-moderate risk profile had greater ∆BL (0.027 ± 0.031, indicating bone increment) than those with high risk (-0.012 ± 0.064, tendency for BL). For regular compliers, no significant differences of annual TL or ∆BL were found between risk groups.

CONCLUSIONS

MPRA models could be used for evaluating the long-term outcomes of Chinese patients with severe GAgP, especially irregular compliers. High-risk patients of MPRAs exhibited more TL and less bone fill than low-to-moderate risk ones.

Toll-like receptor 2 gene polymorphisms associated with aggressive periodontitis in Japanese

BACKGROUND AND OBJECTIVE

Aggressive periodontitis is a rare and very severe periodontal disease of early onset, which is closely associated with Porphyromonas.gingivalis (P.g.) infection in the Japanese population. TLR2 encodes Toll-like receptor 2, which plays an important role in the protective response to P.g. infection. We investigated a possible association between TLR2 and aggressive periodontitis.

MATERIAL AND METHODS

Of 2,460 Japanese patients with periodontitis, 38 patients with aggressive periodontitis were enrolled in this study. These 38 aggressive periodontitis patients and 190 Japanese healthy controls were examined for an insertion/deletion (Ins/Del) polymorphism in exon 1, a polymorphism in intron 1 (rs7696323), and a synonymous polymorphism in exon 3 (rs3804100) in TLR2.

RESULTS

We found significant associations of resistance to aggressive periodontitis with the Ins allele (allele frequency in the patients versus controls, 0.540 vs. 0.676, OR=0.56, 95% confidence interval (CI); 0.34-0.92, p=0.022) and the T allele of rs3804100 (0.579 vs. 0.716, OR=0.55, 95% CI; 0.33-0.91, p=0.018), although the C allele of rs7696323 showed no significant association (0.733 vs. 0.829, OR=0.58). A permutation test of Ins/Del-rs7696323-rs3804100 haplotype revealed a significant association between Ins-C-T haplotype (0.252 vs. 0.479, p=0.0003) and resistance to aggressive periodontitis.

CONCLUSIONS

The TLR2 polymorphisms were suggested to confer protection against aggressive periodontitis in a Japanese population. The association should be replicated in other cohorts to further identify the responsible TLR polymorphism(s) involved in the pathogenesis of aggressive periodontitis.

Association analysis between the -2518MCP-1(A/G) polymorphism and generalized aggressive periodontitis in a Chinese population

BACKGROUND AND OBJECTIVE

It has been suggested that aggressive periodontitis has a genetic basis. Monocyte chemoattractant protein 1 (MCP-1) plays a critical role in the recruitment of monocytes and the development of periodontitis. The -2518MCP-1(A/G) polymorphism has been implicated as a risk or susceptibility factor for a variety of autoimmune conditions and inflammatory diseases. The intent of this investigation was to study whether the -2518MCP-1(A/G) polymorphism is associated with generalized aggressive periodontitis in the Chinese population.

MATERIAL AND METHODS

One hundred and twenty-four patients with generalized aggressive periodontitis and 94 healthy subjects were included in this case-control study. Genomic DNA was isolated from a peripheral blood sample obtained from each subject. Gene polymorphisms of -2518MCP-1(A/G) were analyzed by a standard polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. A logistic regression analysis was performed to test the association between the -2518MCP-1(A/G) genotype (alleles) and generalized aggressive periodontitis with adjustment of the major covariates (gender, age and smoking status).

RESULTS

There was no significant association of the -2518MCP-1(A/G) polymorphism with generalized aggressive periodontitis in the unstratified subjects. However, when patients were stratified by gender, the frequency of the G(+) genotype was significantly lower in female patients with generalized aggressive periodontitis compared with female controls (p = 0.036, adjusted odds ratio = 0.3, 95% CI: 0.1-0.9). In female patients with generalized aggressive periodontitis, the probing pocket depth was larger in subjects with the AA genotype than in subjects with the G(+) genotype (5.07 mm vs. 4.30 mm; Z = -2.470, p = 0.014).

CONCLUSION

The polymorphisms of -2518MCP-1 may play an important role in determining generalized aggressive periodontitis susceptibility in this cohort of Chinese women.

Analysis of plasma calprotectin and polymorphisms of S100A8 in patients with aggressive periodontitis

BACKGROUND AND OBJECTIVE

Calprotectin is an important proinflammatory mediator in various inflammatory diseases and is composed of two subunits (S100A8 and S100A9). However, the level of calprotectin in plasma of patients with aggressive periodontitis and its relationship with gene polymorphisms of S100A8 are unclear.

MATERIAL AND METHODS

The plasma concentrations of calprotectin were measured, using an enzyme immunoassay, in 139 patients with aggressive periodontitis and in 88 periodontally healthy control subjects. These patients were genotyped for the rs3795391 and rs3806232 polymorphisms of S100A8.

RESULTS

The plasma concentration of calprotectin in patients with aggressive periodontitis was significantly higher than in controls (2.17 mg/L vs. 1.72 mg/L, respectively, p = 0.001). The percentage of the AA genotype of S100A8 rs3795391 was significantly higher in patients than in controls (82% vs. 69.3%, respectively, p = 0.027), while the frequency of the allele G was decreased among patients compared with controls (9.6% vs. 16.1%, respectively, p = 0.036), which was especially apparent in men (rs3795391 genotype, p = 0.005; rs3795391 allele, p = 0.015). The mean probing depth in patients carrying the AA genotype was significantly higher than that of patients carrying the GA + GG genotype of two polymorphisms of S100A8 (rs3795391, p = 0.035; rs3806232, p = 0.040), whereas the levels of calprotectin between different genotypes were not significantly different (rs3795391, p = 0.11; rs3806232, p = 0.15).

CONCLUSION

These findings indicate that aggressive periodontitis is associated with elevated levels of plasma calprotectin and that gene polymorphisms of S100A8 may influence the susceptibility and severity of aggressive periodontitis.

Association of single nucleotide gene polymorphism at interleukin-1beta +3954, -511, and -31 in chronic periodontitis and aggressive periodontitis in Dravidian ethnicity

BACKGROUND

Interleukin (IL)-1beta gene polymorphisms are considered a potential risk factor for periodontal disease. The aim of this study is to identify the association of IL-1beta gene polymorphisms with chronic periodontitis and aggressive periodontitis in a Malayalam-speaking Dravidian population from South India.

METHODS

The case-control study consisted of 43 patients with chronic periodontitis and 54 patients with aggressive periodontitis as cases, and the control group consisted of 101 healthy subjects. All subjects were genotyped for IL-1beta +3954, -511, and -31 loci by polymerase chain reaction amplification followed by restriction enzyme digestion and gel electrophoresis. Genotype, allele, and haplotype analyses were done.

RESULTS

Analyses for allele and genotypes showed a high frequency of the C allele and CC genotype for single nucleotide polymorphism IL-1beta +3954 in the group with chronic periodontitis and no difference for patients with aggressive periodontitis compared to controls (P <0.05). Haplotype analysis showed that IL-1beta -31 and -511 were in strong linkage disequilibrium in all groups. The IL-1beta -31 allele T was in linkage with allele T of IL-1beta +3954 in the control group.

CONCLUSIONS

In the Malayalam-speaking Dravidian population, allele C of IL-1beta +3954 appeared to be an important risk factor for chronic periodontitis. The IL-1beta -31 allele T was in linkage with allele T of IL-1beta +3954 in the control group. No gene polymorphisms were found in patients with aggressive periodontitis. More studies with a larger sample size involving the entire cluster of the IL-1beta gene are necessary to determine the exact role of IL-1beta gene polymorphisms in periodontal disease.

Association of vitamin D receptor gene polymorphisms in Chinese patients with generalized aggressive periodontitis

BACKGROUND AND OBJECTIVE

The clinical features suggest that genetic factors may have a strong influence on susceptibility to aggressive periodontitis. The aim of this study was to investigate the association of vitamin D receptor gene polymorphisms with generalized aggressive periodontitis in Chinese patients.

MATERIAL AND METHODS

A restriction fragment length polymorphism (RFLP) for 10,438,141 C to T (rs1544410, BsmI), 10,382,063 A to G (rs731236, TaqI), 10,382,143 C to A (rs7975232, ApaI) and 10,416,201 A to G (rs2228570, FokI) of vitamin D receptor gene was analysed by polymerase chain reaction, followed by digestion with restriction enzymes and gel electrophoresis. The genotypes of 51 generalized aggressive periodontitis patients and 53 periodontally healthy control subjects were analysed. The genotypic and allelic frequencies of each polymorphism site for the patients and control subjects were compared.

RESULTS

The distribution of vitamin D receptor FokI genotypes and alleles between the two groups was significantly different (p = 0.043 and p = 0.012, respectively). The F allele seemed to increase the susceptibility of aggressive periodontitis (odds ratio = 2.02, 95% confidence interval = 1.16-3.50) in Chinese patients. There was no significant difference in the genotype distribution or the allele frequencies of vitamin D receptor BsmI, ApaI and TaqI between two groups.

CONCLUSION

The study indicates that FokI polymorphism of vitamin D receptor gene might be associated with generalized aggressive periodontitis in Chinese patients. In addition, the carriage of F allele increases the risk of developing generalized aggressive periodontitis.

MMP-2, MMP-9 and TIMP-2 gene polymorphisms in Chinese patients with generalized aggressive periodontitis

BACKGROUND

Aggressive periodontitis (AgP) has a genetic basis. It has been reported that the functional gene polymorphisms of matrix metalloproteinase (MMP)-2, MMP-9 and tissue inhibitor of metalloproteinase-2 (TIMP-2) alter their expressions in transcriptional level and they are involved in the tissue destruction of periodontitis. The study was carried out to analyse the association of functional polymorphisms in MMP-2, MMP-9 and TIMP-2 with generalized AgP (G-AgP) in a Chinese population.

MATERIAL AND METHODS

The study population consisted of 79 Chinese patients with G-AgP and 128 healthy controls. DNA was obtained from oral mucosa swab samples. MMP-2 genotypes were determined by PCR-based denaturing high-performance liquid chromatography analysis while MMP-9 and TIMP-2 genotypes were identified by a PCR-based restriction fragment length polymorphism. Chi2 test after Yates' correction was used to investigate the possible association of the genotypes with the G-AgP.

RESULTS

Although gene polymorphisms for MMP-2 and MMP-9 did not show any association with the G-AgP, the analysis of the TIMP-2 -418G to C gene polymorphism revealed significant differences between the patients and controls. Compared with controls, a significant increasing trend of TIMP-2 -418C carrier in the G-AgP patients occurred (p=0.013).

CONCLUSION

It is suggested that the TIMP2 -418G to C gene polymorphism is associated with G-AgP in the Chinese subjects.

The association of the composite IL-1 genotype with periodontitis progression and/or treatment outcomes: a systematic review

BACKGROUND

Genetically transmitted traits such as cytokine gene polymorphisms may accentuate the host inflammatory response to the bacterial challenge and influence susceptibility to periodontitis.

OBJECTIVE

To systematically review the evidence of an association between the interleukin-1 (IL-1) composite genotype, i.e. presence of the allele 2 in the gene clusters IL-1A-889 and in IL-1B +3953, and periodontitis progression and/or treatment outcomes.

MATERIAL AND METHODS

Based on the focused question, a search was conducted for longitudinal clinical trials comparing progression of periodontitis and/or treatment outcomes in IL-1 genotype-positive (carrying allele 2) and IL-1 genotype-negative (not carrying allele 2) subjects. A search in the National Library of Medicine computerized bibliographic database MEDLINE and a manual search were performed. Selection of publications, extraction of data and validity assessment were made independently by two reviewers.

RESULTS

The search provided 122 titles of which 11 longitudinal publications were included. The heterogeneity of the data prevented the performance of a meta-analysis. While findings from some publications rejected a possible role of IL-1 composite genotype on progression of periodontitis after various therapies, other reported a prognostic value for disease progression of the positive IL-1 genotype status. When assessed on a multivariate risk assessment model, several publications concluded that the assessment of the IL-1 composite genotype in conjunction with other covariates (e.g. smoking and presence of specific bacteria) may provide additional information on disease progression. The small sample size of the available publications, however, requires caution in the interpretation of the results.

CONCLUSION

Based on these findings, (i) there is insufficient evidence to establish if a positive IL-1 genotype status contributes to progression of periodontitis and/or treatment outcomes. Therefore, (ii) results obtained with commercially available tests should be interpreted with caution.

Analysis of Tumor Necrosis Factor-α, Transforming Growth Factor-β, Interleukin-10, IL-6, and Interferon-γ Gene Polymorphisms in Patients With Chronic Periodontitis

BACKGROUND

Cytokine gene polymorphisms may have an impact on the susceptibility to and progression of chronic periodontitis. In this study, we analyzed the -1082 interleukin-10 (IL-10), -308 tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta 1 (TGF-beta1) (codons 10 and 25), -174IL-6, and +874 interferon-gamma (IFN-gamma) gene single-nucleotide polymorphisms in a cohort of patients with chronic periodontal disease.

METHODS

The diagnosis was made on the basis of standardized clinical and radiographic criteria. A total of 122 adult patients with chronic periodontitis and 114 unrelated, ethnically and age-matched white control subjects were genotyped by a polymerase chain reaction-sequence-specific primer.

RESULTS

The number of individuals carrying the -174IL-6 CC genotype was significantly higher in the group of patients than in the control group (odds ratio [OR] = 1.896; 95% confidence interval [CI] = 1.106 to 3.250; P = 0.0283). The TGF-beta1 (codon 25) GG (Arg(25)/Arg(25)) genotype was detected more frequently in control subjects than in periodontitis patients (OR = 0.459; 95% CI = 0.230 to 0.920; P = 0.0421).

CONCLUSION

The -174IL-6 and TGF-beta1 (codon 25) single-nucleotide polymorphisms are associated with susceptibility to chronic periodontitis in the population studied.

No correlation of five gene polymorphisms with periodontal conditions in a Greek population

BACKGROUND

Various studies have examined possible correlations between a number of cytokine gene polymorphisms and periodontal disease in populations of different origins. The present study sought the correlation between four single-nucleotide polymorphisms (IL1A+3954, IL1B+4845, TNFA-308, COL1A1 Sp1), a variable number of tandem repeats polymorphism (IL1RN intron 2) and periodontal conditions in subjects of Greek origin.

METHODS

One hundred and ninety-two healthy subjects, stratified as non-periodontitis and periodontitis (chronic and aggressive) cases, participated in the present study. Genotyping was performed by polymerase chain reaction-based techniques using the primers and conditions described in the literature. The frequencies of genotypes between study groups were compared using Genepop v3.3 genetic software and Instat statistical package.

RESULTS

No differences were observed among the groups concerning the distributions of genotypes under investigation.

CONCLUSIONS

Carriage rates of the polymorphisms under investigation in systemically healthy subjects of Greek origin are well within the range reported for Caucasians but these polymorphisms cannot discriminate between non-periodontitis and periodontitis (chronic or aggressive) cases.

Correlation between single nucleotide polymorphisms in a calprotectin subunit gene and risk of periodontitis in a Chinese population

S100A8, the light subunit of calprotectin, has been known to be associated with periodontal inflammation. The present study looked to detect whether three polymorphisms in the upstream region of the S100A8 gene are correlated with periodontitis. Three hundred and twenty one subjects, including chronic periodontitis (CP) patients, aggressive periodontitis (AgP) patients and periodontally healthy controls, were recruited. The SNPs rs3795391, rs3806232 and rs3885688 were analyzed by PCR-RFLP analysis. No person carried the rs3885688 polymorphism in this cohort. For the other two polymorphisms, the combined effects of genotype/allele and gender were shown to be associated with the risk of periodontitis using multivariate logistic regression analysis. The G+ genotype/G allele may be considered to exert a significant protective effect in males against AgP (Genotype: rs3795391: P= 0.032, rs3806232: P= 0.017; Allele: rs3795391: P= 0.024, rs3806232: P= 0.013). Although the combined effects of genotype and gender on CP susceptibility were not observed for these two polymorphisms, there does seem to be increased risk of CP in males with allele A compared to females with allele A (rs3795391: P= 0.008; rs3806232: P= 0.009). Hence we found an important association between polymorphisms in the S100A8 gene and periodontitis in a Chinese population.

Interleukin gene polymorphisms and breast cancer: a case control study and systematic literature review

BACKGROUND

Interleukins and cytokines play an important role in the pathogenesis of many solid cancers. Several single nucleotide polymorphisms (SNPs) identified in cytokine genes are thought to influence the expression or function of these proteins and many have been evaluated for their role in inflammatory disease and cancer predisposition. The aim of this study was to evaluate any role of specific SNPs in the interleukin genes IL1A, IL1B, IL1RN, IL4R, IL6 and IL10 in predisposition to breast cancer susceptibility and severity.

METHODS

Candidate single nucleotide polymorphisms (SNPs) in key cytokine genes were genotyped in breast cancer patients and in appropriate healthy volunteers who were similar in age, race and sex. Genotyping was performed using a high throughput allelic discrimination method. Data on clinico-pathological details and survival were collected. A systematic review of Medline English literature was done to retrieve previous studies of these polymorphisms in breast cancer.

RESULTS

None of the polymorphisms studied showed any overall predisposition to breast cancer susceptibility, severity or to time to death or occurrence of distant metastases. The results of the systematic review are summarised.

CONCLUSION

Polymorphisms within key interleukin genes (IL1A, IL1B, IL1RN, IL4R, IL6 and IL10 do not appear to play a significant overall role in breast cancer susceptibility or severity.

Association of the IL-1RN2 allele with periodontal diseases

OBJECTIVES

Interleukin-1 receptor antagonist (IL-1Ra) gene (IL-1RN) polymorphism is associated with disease susceptibility and activity in several inflammatory diseases. The aim of this study was to investigate IL-1RN genotype and its associations with different periodontal diseases in a group of Turkish subjects.

DESIGN AND METHODS

A total of 293 subjects were included in this study. Genomic DNA was obtained from the peripheral blood of 52 patients with generalized aggressive periodontitis (G-AgP), 51 with chronic periodontitis (CP) and 190 reference subjects. A variable number tandem repeat (VNTR) polymorphism in the second intron of the IL-1RN gene was detected by PCR-based methods. Probing pocket depth, clinical attachment loss, plaque accumulation and bleeding on probing (BOP) were recorded. The data were analyzed by the chi(2) test, logistic regression and Mann-Whitney U test.

RESULTS

There were significant differences among the groups in the distribution of IL-1RN genotypes (P = 0.0001) and allele frequencies (P = 0.0001). The frequency of IL-1RN2 allele 2 positivity was higher in the AgP and CP group than the reference group [odds ratio (OR) 6.654, 95% CI: 3.023-16.648; OR 10.327, 95% CI: 4.758-22.412, respectively]. The percentage of sites with BOP was significantly higher in IL-1RN2+ compared to IL-1RN2- CP patients (P = 0.022).

CONCLUSION

These results suggest that IL-1RN2 allele positivity is associated with periodontal disease in a Turkish population.

Identification of genetic risk factors for periodontitis and possible mechanisms of action

AIM

To review the literature for genetic risk factors associated with periodontitis.

METHODS

Computerized search of the literature in English using key words: Periodontitis; Genes; Mutation; Polymorphism; Risk.

RESULTS AND CONCLUSIONS

Mutations in the cathepsin C gene (CTSC) have been identified as causal for the Papillon-Lefèvre syndrome (PLS), which includes prepubertal periodontitis (PP). Some CTSC mutations are causal for PP without PLS. No relationship has been demonstrated between CTSC mutations and other forms of periodontitis. Genetic polymorphisms in a candidate gene approach have been explored as risk factors for periodontitis. There is limited evidence that some polymorphisms in the genes encoding interleukins (IL)-1, Fc gamma receptors (Fc gammaR), IL-10 and the vitamin D receptor, may be associated with periodontitis in certain ethnic groups. However relatively large variations in carriage rates of the Rare (R)-alleles among studies on any polymorphism were observed. The available studies appear under-powered and do not adequately take into account other pertinent risk factors for periodontitis. Future studies should include larger cohorts, should clearly define phenotypes and should adequately control for other risk factors. In addition to the candidate gene approach, alternative strategies need to be considered to elucidate the gene variations, which confer risk for periodontitis.