Genes and gene polymorphisms associated with periodontal disease

Genetic Association of ICAM-1 (rs5498) Gene Polymorphism With Susceptibility to Stage II Grade B Periodontitis: A Case-Control Study in South Indian Population

INTRODUCTION

In the contemporary perspective, periodontitis is considered a complex issue triggered and perpetuated by bacteria but strongly influenced by the way the body reacts to bacterial plaque. Recent research has indicated that variations in genes might have an impact on the development of periodontitis. This study was conducted to explore a probable link between the genetic variations in intercellular adhesion molecule-1 (ICAM-1) represented by rs5498 and the occurrence of periodontitis.  Methods: A total of 100 participants, 50 with periodontitis and 50 with periodontally healthy or mild gingivitis, were recruited for this study. Whole blood drawn from the participants was used to obtain genomic DNA. The ICAM-1 gene polymorphism (rs5498) was determined using polymerase chain reaction (PCR) amplification and digestion. The ICAM-1 gene's flanking primers were used to amp up the DNA. For statistical analysis, the genotype that was analyzed using the pattern of restriction fragment length polymorphism was recorded. The Chi-square test compared genotype and allele frequency distributions between both groups. The odds ratio with 95% confidence intervals with each individual allele or genotype was used to compute the risk. Statistical significance was established in all tests when the p-value was less than 0.05.

RESULTS

 There was no discernible difference between the genotype frequencies of patients and controls χ2df (P = 0.6065). The findings demonstrated that no significant difference was present between the two groups for homozygous or heterozygous mutant genotypes (AA vs. AG+GG; P = 0.6854). There was no discernible difference in the detected frequencies of the A allele (58% vs. 61%), G allele (42% vs. 39%), TT (16% vs. 24%), AG (40% vs. 36%), and TT genotypes in the studied groups.

CONCLUSION

According to the results of the current investigation, the ICAM-1 (rs5498) gene polymorphism is not associated with periodontitis in the population investigated.

Polymorphism of salivary proteins and risk of periodontal diseases: A systematic review and meta-analysis of clinical studies

OBJECTIVES

The present systematic review and meta-analysis aimed to assess the association between salivary protein polymorphisms and the risk of periodontal diseases (PD).

DATA

The review incorporated cross-sectional, case-control, retrospective/prospective cohort, and randomized controlled trials assessing the influence of salivary protein polymorphisms on the risk of PD development were included in this review.

SOURCES

A thorough literature search was conducted across electronic databases, namely PubMed, Scopus, Embase, and Web of Science, without any restrictions on publication language and year.

STUDY SELECTION

A total of 168 studies were identified, of which 19 were eligible for inclusion. The risk of bias (RoB) assessment of the included studies was conducted at the methodological level.

RESULTS

A total of 16 studies were included. Polymorphism in the gene encoding TNF-α was found to be protective against gingivitis, while those encoding IL-1α and IL-1β were associated with developing gingivitis. Of the 42 proteins investigated, various gene polymorphisms were identified as protective or risk factors for periodontitis. Protective genes include CFH, DNMT1, OPRM1, and TLR9. Conversely, certain salivary protein genes (e.g., CRP, ERN1, FAM5C, IDH2, LTA, TET2, MPA, NLRP3, TLR4) were associated with periodontitis risk. Notably, IL6, MMP9, and MUC7 genes showed no association with PD, while MMP13 was linked to early implant loss. Overall, the meta-analysis found a statistically significant association between salivary proteins' polymorphisms and risk of PD.

CONCLUSIONS

Salivary protein polymorphisms significantly influence PD, revealing protective and risk-associated genotypes. Despite limitations, findings suggest therapeutic targets, emphasizing the complex genetics-periodontal health interplay.

CLINICAL SIGNIFICANCE

This study unveils salivary protein polymorphisms as pivotal factors in PD. Protective genes including CFH and TLR9, and risk-associated genes including CRP and TLR4, indicate a genetic basis for PD susceptibility.

The Impact of IL1B rs1143634 and DEFB1 rs11362 Variants on Periodontitis Risk in Phenylketonuria and Type 1 Diabetes Mellitus Patients in a Latvian Population

OBJECTIVES

Periodontitis is a multifactorial disease that affects approximately 11% of the global population. The objective of this study was to examine whether, among individuals with phenylketonuria and type 1 diabetes mellitus, those with the IL1B rs1143634 and/or DEFB1 rs11362 genetic variants exhibit a higher periodontitis risk compared to healthy controls.

MATERIALS AND METHODS

In all, 43 phenylketonuria patients (aged 12-53), 28 type 1 diabetes mellitus patients (aged 11-40), and 63 healthy controls (aged 12-53) were included. The evaluation of periodontitis risk was conducted using the Silness-Löe plaque index, the Greene-Vermillion index, and an assessment for the necessity of calculus removal. Genetic variants rs1143634 and rs11362 were genotyped from salivary samples using restriction length polymorphism analysis.

RESULTS

The DEFB1 rs11362 variant was associated with higher Silness-Löe and Greene-Vermillion index scores in phenylketonuria patients (p = 0.011 and p = 0.043, respectively). The IL1B rs1143634 variant was associated with lower calculus removal necessity in type 1 diabetes mellitus patients (p = 0.030). Clinical examination showed the worst oral hygiene index scores for PKU patients. PKU patients also reported the least consistent tooth brushing and flossing habits.

CONCLUSIONS

Genetic associations between DEFB1 rs11362 and IL1B rs1143634 variants and oral hygiene indices were observed in the PKU and T1DM groups, suggesting that genetic factors may contribute to periodontal health differences in these populations. Further research with a larger sample size is needed to confirm these findings and develop targeted oral health interventions.

Genetic Polymorphism and Gene Expression of β-Defensin-1 in Periodontitis Associated With Type 2 Diabetes Mellitus

Introduction Periodontitis is a multifactorial disease caused by periodontopathic bacteria and influenced by both genetic and environmental factors. Genetic predispositions are found to play a crucial part in the onset and progression of periodontal disease. There is a two-way relationship between diabetes and periodontitis with severe periodontal tissue destruction seen in diabetic patients. Antimicrobial peptide, β-defensin-1 (DEFB1 gene), plays an important role in the innate immune responses and forms the first line of host defense against periodontal pathogens. Single nucleotide polymorphisms (SNPs) in the specific genetic loci of the DEFB1 gene and its expression level could confer a degree of risk or protection from periodontitis associated with diabetes. The present study determined the association between SNPs at the 5' untranslated region (UTR) in the DEFB1 gene and susceptibility to periodontitis associated with type 2 diabetes mellitus (T2DM) and analyzed the effect of 5' UTR polymorphisms on DEFB1 gene expression. Methods SNPs in the 5' UTR of the DEFB1 gene (-20G>A (rs11362), -44C>G (rs1800972), and -52G>A (rs1799946)) were genotyped by polymerase chain reaction (PCR) followed by Sanger sequencing. The study group included periodontitis (n = 40), periodontitis with T2DM (n = 20), and periodontally and systemically healthy as controls (n = 40). DEFB1 gene expression was determined by real-time PCR in the study group comprising periodontitis (n = 20), periodontitis with T2DM (n = 15), and healthy controls (n = 20). The effect of 5' UTR polymorphisms on the expression was analyzed by statistical tools. Results Statistically significant higher prevalence of the variant AA genotype of rs11362 was observed in periodontitis (odds ratio (OR) = 3.64, 95% confidence Interval (CI) = 1.16-11.43, p = 0.04) and periodontitis with T2DM (OR = 5.14, 95% CI = 1.29-20.5, p = 0.03) in comparison with healthy controls. Moreover, there was a significant increase of the variant AA genotype of rs1799946 in periodontitis (OR = 3.88, 95% CI = 1.19-12.68, p = 0.04) compared to healthy controls. DEFB1 gene expression was downregulated in periodontitis and upregulated in periodontitis with T2DM patients when compared to healthy controls but was not statistically significant. No significant association was found for the effect of SNPs of the DEFB1 gene on its expression. Conclusion From the SNP analysis, it can be inferred that the presence of SNPs at the 5' UTR (rs11362 and rs1799946) in the DEFB1 gene may be an important predictive factor for periodontitis.

Genomic Medicine in Canine Periodontal Disease: A Systematic Review

Genomic medicine has become a growing reality; however, it is still taking its first steps in veterinary medicine. Through this approach, it will be possible to trace the genetic profile of a given individual and thus know their susceptibility to certain diseases, namely periodontal disease. This condition is one of the most frequently diagnosed in companion animal clinics, especially in dogs. Due to the limited existing information and the lack of comprehensive studies, the objective of the present study was to systematically review the existing scientific literature regarding genomic medicine in canine periodontal disease and determine which genes have already been studied and their probable potential. This study followed the recommendations of the PRISMA 2020 methodology. Canine periodontal disease allied to genomic medicine were the subjects of this systematic review. Only six articles met all of the inclusion criteria, and these were analyzed in detail. These studies described genetic variations in the following genes: interleukin-6, interleukin-10, interleukin-1, lactotransferrin, toll-like receptor 9, and receptor activator of nuclear factor-kappa B. Only in two of them, namely interleukin-1 and toll-like receptor 9 genes, may the identified genetic variations explain the susceptibility that certain individuals have to the development of periodontal disease. It is necessary to expand the studies on the existing polymorphic variations in genes and their relationship with the development of periodontal disease. Only then will it be possible to fully understand the biological mechanisms that are involved in this disease and that determine the susceptibility to its development.

Prevalence of apical periodontitis in patients with autoimmune diseases: A case-control study

AIM

The purpose of this case-control study was to compare the prevalence of apical periodontitis (AP) in patients affected by autoimmune disorders (AD) (inflammatory bowel disease [IBD], rheumatoid arthritis [RA] and psoriasis [Ps]) with the prevalence of AP in subjects without AD. The prevalences of AP in patients taking biologic medications, conventional medications and no medication were also compared.

METHODOLOGY

Eighty-nine patients (2145 teeth) with AD were investigated and the control group included 89 patients (2329 teeth) with no systemic diseases. Full dental panoramic tomograms were used to determine the periapical status of the teeth. Additional variables investigated included patient's socio-demographic characteristics, medications taken by AD patients, the decayed, missing and filled teeth (DMFT) index. The chi-square test and logistic regression analysis were used to evaluate the correlation between AD and AP. p-Values lower than .05 were considered to be statistically significant.

RESULTS

The prevalence of AP was 89.9% in AD patients and 74.2% in control subjects (odds ratio [OR] = 3.75, p = .015). The DMFT score was found to be significantly higher in the AD group (p = .004). Patients with RA had the highest risk of being affected by AP, whereas those with IBD had the lowest risk. Multiple binary logistic regression analysis indicated that the teeth of AD patients who were not taking any medication or were being treated with biologic disease-modifying anti-rheumatic drugs (bDMARDs) had a higher risk of being affected by AP than did the teeth of the control subjects (OR = 1.42 and OR = 2.03, respectively; p = .010). The teeth of patients taking conventional DMARDs (cDMARDs) were less affected by AP compared with those of patients taking bDMARDs.

CONCLUSIONS

Patients with AD, whether treated or not with biologic medications, showed a higher prevalence of AP than did those in the control group. The DMFT index score, which was higher in AD patients compared with controls was identified as a significant predictor of AP prevalence.

Anti-Inflammatory Benefits of Food Ingredients in Periodontal Diseases

Periodontitis is a multi-faceted inflammatory disease that impacts the gingiva and the structures that support our teeth, and may eventually increase tooth mobility and the risk of tooth loss. Inflammation is a viable therapeutic target of periodontitis for both biologic (dietary) and host modulatory agents/drugs. Conventional therapeutic approaches for periodontitis, including nonsurgical or surgical periodontal therapy as well as occasional adjunctive antimicrobial therapy, have been only marginally effective. Malnutrition, or at least poor dietary habits, can be highly prevalent among patients with periodontal diseases. As several food nutrients can aid in periodontal healing and regeneration, there is a critical need to evaluate natural dietary sources and supplement ingredients that can counterbalance the inflammatory processes and improve the periodontal status of our patients. Here, we reviewed the current state of knowledge (search period: 2010 to 2022; PubMed and Web of Science) on the anti-inflammatory actions of food ingredients and supplements in clinical studies of patients with periodontal diseases. A diet that includes fruits and vegetables, omega-3 polyunsaturated fatty acids, and supplements of vitamins and plant-derived compounds seems to counteract gingival inflammation and has a promising therapeutic impact in patients with periodontal diseases. Despite the positive indications that several nutrients can be used as an adjunct to periodontal therapy, additional studies with bigger sample sizes and longer follow-up periods are needed to elucidate their therapeutic benefits and the most effective doses and administration.

Single nucleotide variants in the IL33 and IL1RL1 (ST2) genes are associated with periodontitis and with Aggregatibacter actinomycetemcomitans in the dental plaque biofilm: A putative role in understanding the host immune response in periodontitis

The Interleukin (IL)-33 is important in several inflammatory diseases and its cellular receptor is the Interleukin 1 receptor-like 1 (IL1RL1), also called suppression of tumorigenicity 2 ligand (ST2L). This study investigated associations between single nucleotide variants (SNVs) in the IL33 gene and in the IL1RL1 (ST2) gene with periodontitis. Additionally, aimed to determine the role of Aggregatibacter actinomycetemcomitans (Aa) relative amount in the subgingival biofilm in these associations. A cross-sectional study was carried out with 506 individuals that answered a structured questionnaire used to collect their health status, socioeconomic-demographic, and behavioral characteristics. Periodontal examination was performed to determine the presence and severity of periodontitis, and subgingival biofilm samples were collected to quantify the relative amount of Aa by real time polymerase chain reaction. Human genomic DNA was extracted from whole blood cells and SNV genotyping was performed. Logistic regression estimated the association measurements, odds ratio (OR), and 95% confidence interval (95%CI), between the IL33 and ST2 genes with periodontitis, and subgroup analyses assessed the relative amount of Aa in these associations. 23% of individuals had periodontitis. Adjusted measurements showed a statistically significant inverse association between two SNVs of the ST2; rs148548829 (C allele) and rs10206753 (G allele). These two alleles together with a third SNV, the rs11693204 (A allele), were inversely associated with moderate periodontitis. One SNV of the IL33 gene also showed a statistically significant inverse association with moderate periodontitis. Nine SNVs of the ST2 gene were inversely associated with the relative amount of Aa. In the high Aa subgroup, there was a direct association between 11 SNVs of the ST2 gene and moderate periodontitis and two SNVs of the ST2 gene and severe periodontitis, and eight SNVs of the ST2 gene and periodontitis. These exploratory findings of genetic variants in IL-33/ST2 axis support the concept that the different tissue responses among individuals with periodontitis may be modulated by the host's genetics, influencing the physiopathology of the disease.

Association of SRXN1 Receptor Gene Polymorphism with Susceptibility to Periodontitis

Background

Emerging evidence suggests that oxidative stress forms a key component in the etiopathogenesis of periodontitis. Literature evidence have shown potential antioxidants responsible for combating the pro-oxidants which stress the periodontium, but the peroxiredoxin-sulfiredoxin system is explored very minimally in periodontal disease. Thus, the present study was aimed to evaluate the genetic association of SRXN1 receptor gene polymorphism (rs6053666).

Materials and Methods

A total of 100 subjects were recruited for this study, which included 50 Periodontitis patients (Stage II and above based on the criteria of American Association of Periodontology-2018) and 50 periodontally healthy or mild gingivitis. Genomic DNA was extracted from the whole blood collected from the subjects. DNA was amplified using specific primers flanking the BtgI region of the SRXN1 receptor gene. The amplicon was further subjected to genotyping using restriction fragment length using BtgI enzyme. The genotype obtained based on the restriction fragment length polymorphism pattern was recorded and used for statistical analysis. The distribution of genotypes and allele frequencies in the periodontitis and control groups were compared using the Chi-square test. The risk associated with individual alleles or genotypes was calculated as the odds ratio with 95% confidence intervals. Statistical significance in all tests was determined at P < 0.05.

Results

The genotype frequency and distributions of SRXN1 receptor BtgI polymorphism did not differ significantly at ꭕ2df (P = 0.557). Our study results showed that homozygous and heterozygous mutant genotypes had no significant difference (CC vs. CT + TT) between the periodontitis patients and control group with a P = 0.4266. The detected frequency of CT (38% vs. 34%) and TT (42% vs. 52%) genotype showed no significant difference between control and test group. There was no significant difference in C allele (39% vs. 31%) and T allele (61% vs. 69%) between the test and control group.

Conclusion

The present study denotes that SRXN1 receptor gene polymorphism is not associated with periodontitis in the study group analyzed.

Analysis of GLT6D1 and CDKN2BAS gene polymorphisms in Brazilian patients with advanced periodontitis

Gene polymorphisms can predispose to periodontal disease, as demonstrated by the well-documented association between aggressive periodontitis and single nucleotide polymorphisms (SNPs) such as rs153745 in the GLT6D1 gene and rs3217992 in the CDKN2BAS gene. The purpose of this study was to evaluate the presence of these SNPs in Brazilian patients with advanced periodontitis (stages III/IV, Grade B/C) vs. healthy controls. A total of 100 patients with periodontitis (Group BC) were enrolled. Of these, 51 patients were classified as stage III and 49 patients were classified as stage IV, and 52 were Grade B (Group B) and 48 were Grade C (Group C). The control Group consisted of 61 healthy subjects. DNA samples extracted from buccal epithelial cells were used to genotype the SNPs rs1537415 (GLT6D1) and rs3217992 (CDKN2BAS) by real-time quantitative PCR. No significant differences in polymorphism frequency were found between the control Group and each of the patient groups (BC, B, or C), and Group B did not differ from Group C. In conclusion, the evaluated SNPs had no significant influence on the prevalence of periodontal disease in the sampled Brazilian population.

The roles of ANRIL polymorphisms in periodontitis: a systematic review and meta-analysis

OBJECTIVES

The aim of this study is to investigate the potential role of ANRIL polymorphisms in susceptibility to periodontitis.

METHODS

The authors searched Pubmed, Web of Science, and Scopus up to April 2021 to identify all published studies without any language restriction on the association between ANRIL and periodontitis. A meta-analysis of all ANRIL variants replicated by three or more studies was performed by testing multiple genetic models of association. Pooled odds ratios and 95% confidence intervals (CI) were used to estimate associations. Tests for sensitivity and publication bias were performed.

RESULTS

Twenty-two variants in the ANRIL gene were examined for their potential association with the risk of periodontitis. However, only 4 (rs1333048, rs1333042, rs2891168, rs496892) are replicated at least three or more studies. The ANRIL rs1333048 was the most replicated polymorphisms with five articles, seven different populations comprising of 1331 cases, and 2624 controls. The pooled overall analysis showed that rs1333048, rs1333042, rs2891168, and rs496892 polymorphisms were associated with susceptibility to periodontitis in the whole population in allele contrast and dominant models. Moreover, similar to the overall analysis, rs1333048 polymorphism showed a significant association with grade C periodontitis (known as aggressive periodontitis in 1999 classification) in allele contrast (OR = 1.16) and dominant models (1.19). Interestingly, subgroup analysis also showed rs1333048 polymorphism might influence predisposition to a slowly progressive form of periodontitis (known as chronic periodontitis in 1999 classification).

CONCLUSION

Our findings suggest that the ANRIL rs1333048, rs1333042, rs2891168, and rs496892 polymorphisms might influence predisposition to periodontitis, particularly in Caucasians.

CLINICAL SIGNIFICANCE

ANRIL gene may represent a potential risk marker for periodontitis.

Prevalence of periodontitis in people clinically diagnosed with diabetes mellitus: a meta-analysis of epidemiologic studies

AIMS

The relationship between diabetes mellitus and periodontitis has long been discussed, but the conclusion of this relationship was controversial. We conducted this meta-analysis to explore the association between diabetes mellitus and the prevalence of periodontitis.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were searched for studies reporting associations of periodontitis with diabetes. Gray literature was integrated from the Open-Gray database. Prevalence estimates and odds ratios were extracted by two independent reviewers and synthesized through meta-analyses.

RESULTS

Twenty-seven papers met the inclusion criteria involving 3092 diabetic patients and 23,494 controls. Overall prevalence of periodontitis was 67.8% in diabetics (combined types) and 35.5% in patients without diabetes (OR, 1.85; 95%CI, 1.61-2.11). Probing depth (MD 0.23; 95% CI, 0.17-0.29; I² = 25%) and plaque index (MD, 0.20; 95% CI, 0.18-0.23; P = 0.59; I² = 0%) severity scores were significantly greater among the diabetic group.

CONCLUSIONS

The prevalence and severity of periodontitis are greater in patients with diabetes than in non-diabetic populations.

Waistline to the gumline: Relationship between obesity and periodontal disease-biological and management considerations

Obesity is a pandemic and periodontitis is the sixth most prevalent disease in the world. These two noncommunicable diseases share several risk determinants. Epidemiologic evidence from the last 2 decades has established an increase in periodontitis prevalence in obese and overweight individuals. Biologic mechanisms potentially linking obesity and periodontal disease are adiposity-associated hyperinflammation, microbial dysbiosis, altered immune response, specific genetic polymorphisms, and increased stress. However, because of the lack of longitudinal interventional studies and randomized clinical trials, there is insufficient evidence to determine the cause-effect relationship between these two diseases. Despite this, the negative impact of obesity on oral health is well established. Several logistic and physiologic complications are associated with treating obese patients in a dental setting, and it requires an interprofessional team approach. Oral health care professionals need to be aware of the specific management considerations while rendering for this cohort, including modified practice facility and equipment, tailored supportive periodontal therapy, and heightened precaution during conscious sedation and surgical procedures.

IL-1B(3954) polymorphism and red complex bacteria increase IL-1β (GCF) levels in periodontitis

OBJECTIVE

The aim of this study was to compare IL-1β levels in gingival crevicular fluid (GCF) from healthy and periodontitis sites of IL-1B(3954)-Single Nucleotide Polymorphism (SNP) positive and IL-1B(3954)-SNP negative periodontitis subjects in association with their bacterial profiles.

BACKGROUND

Susceptibility to periodontitis has been associated with several risk factors, including allelic variants at multiple gene loci. Variations in the IL-1 gene cluster have been linked with increased risk for periodontitis. IL-1B(3954)-SNP has been previously associated with increased levels of IL-1β in GCF or periodontal tissues in chronic periodontitis patients, as well as higher levels of specific periodontal pathogens. There is insufficient evidence to conclude if IL-1B gene polymorphisms affect the susceptibility to periodontitis by ultimately modulating the levels of IL-1β in GCF, the subgingival microbial profile or both.

MATERIALS AND METHODS

GCF, subgingival plaque, and buccal epithelial cells were collected from 32 individuals with periodontitis. GCF IL-1β levels were measured by an enzyme-linked immunosorbent assay (ELISA). Bacterial plaque samples were analyzed for 11 periodontal pathogens using polymerase chain reaction (PCR) analysis with specific primers for the 16SrRNA gene of each bacterium. IL-1B(3954)-SNP status was determined by identifying the carriers of the polymorphic T allele.

RESULTS

A significant association was shown between IL-1B(3954)-SNP and IL-1β GCF levels (amount and concentration). The concomitant presence of two or three red complex bacterial species was associated with increased IL-1β GCF levels in periodontitis sites (site-level analysis). The concurrent presence of all three red complex periodontal pathogens and IL-1B(3954)-SNP was associated with the highest IL-1β GCF levels in periodontitis sites.

CONCLUSIONS

Our results indicate an independent association of both IL-1B(3954)-SNP and red complex bacterial species with increased IL-1β levels in GCF of periodontitis sites. A better understanding of the interaction between genetics, bacteria, and inflammation is essential to develop more effective diagnostic, prognostic, and therapeutic tools for periodontitis.

The Influence of Genetics in Myopia Control: A Pilot Study

Background: Many epidemiological and experimental studies have established that myopia is caused by a complex interaction between common genetic and environmental factors. The objective of this study was to describe and compare the allelic and genotypic frequencies of the rs524952 (GJD2), rs8000973 (ZIC2), rs1881492 (CHRNG), rs1656404 (PRSS56), rs235770 (BMP2), and rs7744813 (KCNQ5) SNPs (single-nucleotide polymorphism) between responder and nonresponder patients who had undergone a two-year treatment with lenses for myopia control. Method: Twenty-eight participants from the MiSight Assessment Study Spain (MASS), who had received treatment for myopia control for two years with MiSight contact lenses, were examined. The criteria for better/worse treatment response was the change in the axial length (< / ≥ 0.22 mm two years after the treatment). The clinical procedure consisted of the extraction of a saliva sample, and the participants also underwent an optometric examination. Genetic data were analyzed using SNPStats software (Catalan Institute of Oncology, Barcelona, Spain), and statistical analysis was performed using SPSS v.25 (SPSS Inc., Chicago, IL, USA). Demographic variables were analyzed using the Student’s t-test. Results: The T allele, the one with the lowest frequency, of the “rs235770” SNP was associated with a better treatment response [AL/CR (axial length/corneal radius): OR = 3.37; CI = 1.079–10.886; SE (spherical equivalent): OR = 1.26; CI: = 0.519–57.169; p = 0.019). By performing haplotype analysis, significant differences were found between the rs235770…rs1881492 and rs235770–rs1656404 polymorphisms. The latter presented a strong linkage disequilibrium with each other (r² ≥ 0.54). Conclusion: The result of lens therapies for myopia control could vary depending on genetic variants. Studies with a larger sample are needed to confirm the results presented in this pilot study.

Risk Factors, Mechanisms and Treatments of Thromboangiitis Obliterans: An Overview of Recent Research

BACKGROUND

Thromboangiitis obliterans (TAO) is a nonatherosclerotic thromboticocclusive vasculitis that affects the vessels of the small and medium-sized extremities. No explicit etiology or pathogenesis of TAO has been proven, and more effective treatments are needed.

OBJECTIVE

The study aimed to summarize and present an overview of recent advances regarding the risk factors, mechanisms and treatments of TAO and to organize the related information in figures to provide a comparatively complete reference.

METHODS

We searched PubMed for English-language literature about TAO without article type limits, including articles about the risk factors, pathological mechanisms and treatments of TAO in the last 10 years with essential supplements (references over ranges and English abstracts of Russian literature).

RESULTS

After screening content of works of literature, 99 references were evaluated. We found that risk factors of TAO include smoking, gene factors and periodontal diseases. The underlying mechanism of TAO involves oxidative stress, immunity, hemodynamic changes, inflammation and so on. Moreover, similarities in genetic factors and cigarette relevance existed between periodontal diseases and TAO, so further study of relationship was required. For TAO treatment, medicine, endovascular intervention and revascularization surgery, autologous cell therapy and novel therapies were also mentioned. Besides, a hypothesis that infection triggers autoimmunity in TAO could be speculated, in which TLR4 plays a key role.

CONCLUSION

1. A hypothesis is put forward that infections can trigger autoimmunity in TAO development, in which TLR4, as a key agent, can activate immune signaling pathways and induce autoimmune cytokines expression. 2. It is suggested to reconsider the association between periodontal diseases and TAO, as they share the same high-risk population. Controlling periodontal disease severity in TAO studies may provide new clues. 3. For TAO treatment, endovascular intervention and autologous cell therapy both showed promising long-term therapeutic effectiveness, in which autologous cell therapy is becoming more popular, although more clinical comparisons are needed.

Interleukin Gene Variability and Periodontal Bacteria in Patients with Generalized Aggressive Form of Periodontitis

Host genetic predispositions to dysregulated immune response can influence the development of the aggressive form of periodontitis (AgP) through susceptibility to oral dysbiosis and subsequent host-microbe interaction. This case-control study aimed to perform a multilocus analysis of functional variants in selected interleukin (IL) genes in patients with the generalized form of AgP in a homogenous population. Twelve polymorphisms in IL-1 gene cluster, IL-6 and its receptor, IL-10, IL-17A, and IL-18 were determined in 91 AgP patients and 210 controls. Analysis of seven selected periodontal bacteria in subgingival sulci/pockets was performed with a commercial DNA-microarray kit in a subgroup of 76 individuals. The pilot in vitro study included stimulation of peripheral blood monocytes (PBMC) from 20 individuals with periodontal bacteria and measurement of IL-10 levels using the Luminex method. Only the unctional polymorphism IL-10 −1087 A/G (rs1800896) and specific IL-10 haplotypes were associated with the development of the disease (p < 0.05, P_corr > 0.05). Four bacterial species occurred more frequently in AgP than in controls (p < 0.01, P_corr < 0.05). Elevated IL-10 levels were found in AgP patients, carriers of IL-10 −1087GG genotype, and PBMCs stimulated by periodontal bacteria (p < 0.05, P_corr > 0.05). We therefore conclude that a combination of genetic predisposition to the altered expression of IL-10 and the presence of specific periodontal bacteria may contribute to Th1/Th2 balance disruption and AgP development.

Periodontal inflammation: Integrating genes and dysbiosis

Biofilm bacteria co‐evolve and reach a symbiosis with the host on the gingival surface. The disruption of the homeostatic relationship between plaque bacteria and the host can initiate and promote periodontal disease progression. Recent advances in sequencing technologies allow researchers to profile disease‐associated microbial communities and quantify microbial metabolic activities and host transcriptional responses. In addition to confirming the findings from previous studies, new putative pathogens and novel genes that have not previously been associated with periodontitis, emerge. For example, multiple studies have reported that Synergistetes bacteria are associated with periodontitis. Genes involved in epithelial barrier defense were downregulated in periodontitis, while excessive expression of interleukin‐17 was associated with a hyperinflammatory response in periodontitis and with a unique microbial community. Bioinformatics‐enabled gene ontology pathway analyses provide a panoramic view of the bacterial and host activities as they shift from periodontal health to disease. Additionally, host innate factors, such as genetic variants identified by either a candidate‐gene approach or genome‐wide association analyses, have an impact on subgingival bacterial colonization. Transgenic mice carrying candidate genetic variants, or with the deletion of candidate genes mimicking the deleterious loss‐of‐function variant effect, provide experimental evidence validating the biologic relevance of the novel markers associated with the microbial phenotype identified through a statistical approach. Further refinement in bioinformatics, data management approaches, or statistical tools, are required to gain insight into host‐microbe interactions by harmonizing the multidimensional “big” data at the genomic, transcriptional, and proteomic levels.

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 Fc gamma-receptor genes polymorphisms with chronic periodontitis and Peri-Implantitis

This study was conducted on 87 patients with chronic periodontitis (CP), 50 patients with peri-implantitis and 90 periodontally healthy individuals referring to the Department of Periodontics for evaluating the association between Fc gamma-receptor genes polymorphisms with CP and peri-implantitis. After obtaining consent, venous blood samples (5cc) were obtained from patients and DNA was extracted using Miller's salting-out method. Polymerase chain reaction (PCR)-restriction fragment length polymorphism and tetra-primer amplification refractory mutation system-PCR methods were used to assess the polymorphisms of FcγRs IIa, IIIa, and IIIb genes. Analyzing showed a significant association between specific genotypes with increasing CP and peri-implantitis risks in codominant and dominant models. For FcγR IIIa, analyzing revealed a significant association between specific genotypes with increasing CP and peri-implantitis risks in codominant, dominant, and recessive models. For FcγR IIIb, we also detected a significant association between specific genotypes with increasing CP and peri-implantitis risks in codominant, dominant, and recessive models ( P < 0.05). According to the results of this study, the FCGRIIa (rs1801274), FCGRIIIa (rs396991), and FCGRIIIb (rs1050501) polymorphisms were significantly associated with CP and peri-implantitis and may have a role in the pathogenesis of these diseases.

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.

Association of CYP1A1 rs1048943 variant with aggressive periodontitis and its interaction with hyperlipidemia on the periodontal status

BACKGROUND AND OBJECTIVE

CYP1A1 rs1048943 polymorphism was reported to be correlated with periodontitis; however, its association with aggressive periodontitis (AgP) has not yet been investigated. The aim of the study was to investigate the association between the CYP1A1 gene rs1048943 variant with generalized aggressive periodontitis (GAgP) and platelet activation and analyse whether its interaction with hyperlipidemia affects periodontal status in a Chinese population.

METHODS

A case-control study of 224 GAgP patients and 139 healthy controls was conducted. The clinical parameters of probing depth (PD), attachment loss (AL) and bleeding index (BI) were recorded. Platelet count (PLT), platelet distribution width (PDW), platelet large cell ratio (PLCR), mean platelet volume (MPV), serum total cholesterol (TC), triacylglycerol (TG), high and low-density lipoprotein (HDL and LDL) were also measured. The CYP1A1 rs1048943 SNP was genotyped by time-of-flight mass spectrometry. Logistic and linear regression models were used to measure correlation.

RESULTS

The CYP1A1 rs1048943 AG/GG genotype was associated with GAgP (OR = 1.56, 95%CI: 1.01, 2.42), PD, AL and decreased PDW, PLCR and MPV after adjustment for covariates. Gene-lipid interactions were found between CYP1A1 rs1048943 and HDL for PD (P_interaction  = 0.0033), BI (P_interaction  = 0.0311) and AL (P_interaction  = 0.0141) and between CYP1A1 rs1048943 and LDL for PD (P_interaction  = 0.013) among patients with GAgP.

CONCLUSION

The G allele of the CYP1A1 rs1048943 gene was associated with GAgP, periodontal status and platelet-related inflammation status in a Chinese population. Hyperlipidemia could modulate the effect of CYP1A1 rs1048943 on the periodontal status of GAgP.

The influence of vitamin D supplementation on local and systemic inflammatory markers in periodontitis patients: A pilot study

OBJECTIVES

Vitamin D deficiency/insufficiency is a worldwide public health issue that has been linked to numerous inflammatory disorders, including periodontitis. There is increasing support for a role for adequate vitamin D levels in overall health. Populations with darker skin color have a higher prevalence of vitamin D deficiency/insufficiency and periodontitis. The purpose of this small pilot study was to investigate the influence of 12 weeks of 25(OH)D vitamin D supplementation (VDS) on mediators of systemic inflammation in dark-skinned, periodontitis patients.

MATERIALS AND METHODS

A total of 23 patients with moderate to severe periodontitis were randomly assigned to the vitamin D group or placebo group and received intensive single visit scaling and root planning to elicit a systemic inflammatory response.

RESULTS

Vitamin D supplementation increased serum 25(OH)D levels approximately 2-fold over baseline levels; moreover, VDS group had reduced peripheral blood CD3 and CD3+CD8+ cytotoxic T lymphocyte (CTLs) counts and reduced pro-inflammatory salivary cytokines. In contrast, VDS group had higher levels of the autophagy-related proteins and other proteins crucial for anti-microbial autophagy in whole blood PBMCs.

CONCLUSION

In conclusion, VDS has multiple benefits for reducing systemic inflammation and promoting induction of autophagy-related proteins related to anti-microbial functions.

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.

Toll-like receptor 9 gene in Periodontal Disease - A promising biomarker

Periodontal Disease is an infectious and inflammatory disorder triggered mainly by periodontopathogenic bacteria, however, as a multifactorial disease, several factors modulate its progression, namely, genetic factors. Toll-like receptors (TLR) recognize molecular patterns present in pathogens and trigger an immune response against them. Thus, sequences variants in TLR genes seem to have the potential to modify the predisposition to Periodontal Disease and its progression. Based on this fact, TLR9 gene were analysed in a case-control study. DNA was obtained from 90 dogs (50 control and 40 cases) and a fragment of TLR9 gene was amplified by PCR and sequenced. The variants were identified by comparison with the dog wild type sequences. Our results suggest that rs375556098 and rs201959275 polymorphisms in the TLR9 gene are good candidates to become biomarkers of the canine predisposition to Periodontal Disease. It's important to notice that these polymorphic sites exist in Human exactly in the same codon. Since the dog is the best animal model to replicate the pathophysiological mechanisms of human Periodontal Disease, these results can potentially be extrapolated to humans.

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.

Evaluation of Association of Vitamin D Receptor Genetic Polymorphism with Severe Chronic Periodontitis in an Ethnic Tamilian Population

BACKGROUND

Periodontitis is a multifactorial disease characterized by inflammatory responses to increased levels of subgingival pathogens, resulting in connective tissue destruction and alveolar bone loss. The susceptibility of an individual is determined by the complex interplay of the host, genetic, and environmental factors. Vitamin D, a secosteroid hormone, interacts with its nuclear receptor vitamin D receptor (VDR) to regulate crucial biological processes, such as bone metabolism and immune function modulation. Various studies have been conducted in different populations to analyze the association of VDR gene polymorphisms with chronic periodontitis, as these polymorphisms have been demonstrated to play vital roles in the pathogenesis of other diseases.

OBJECTIVE

The aim of the present study was to determine the prevalence and association of the VDR TaqI gene polymorphism with severe chronic periodontitis in an Ethnic Tamilian population.

MATERIALS AND METHODS

A total of 140 subjects were recruited for the study, of which 70 were diagnosed with severe chronic periodontitis and 70 had healthy gums. Each subject's medical and dental histories were taken, and periodontal examinations were performed. Genomic DNA was extracted and genotyping of the VDR gene at the TaqI site was carried out using polymerase chain reaction/restriction fragment length polymorphism. The frequencies of genotypes and alleles were analyzed between the study groups.

RESULTS

The frequency of homozygous TT genotype was 40%, for both the severe chronic periodontitis and the healthy control groups. The distribution of heterozygous Tt genotype was 42.9% in the severe chronic periodontitis group and 47.1% in the healthy control group. The frequency of homozygous tt genotype was 17.1% in the severe chronic periodontitis group and 12.7% in the healthy control group. Although the prevalence of genotype tt and t allele was slightly increased in severe chronic periodontitis patients compared with healthy controls, the frequency of VDR genotype between the study groups was not statistically significant (p-value = 0.751).

CONCLUSION

This present study performed in an Ethnic Tamilian population does not support an association between either of the TaqI alleles within the VDR gene and Severe Chronic Periodontitis.

Periodontal disease susceptible matrilines in the Cayo Santiago Macaca mulatta macaques

OBJECTIVE AND BACKGROUND

The expression of periodontitis, including age of onset, extent, and severity is considered to represent an interaction of the individual's oral microbiome and host response to the microbial challenge that is modified by both genetics and environmental factors. The aim of this study was to determine the distribution of periodontitis in a population of nonhuman primates, to document features of familial distribution that could reflect heritability and transmission of microbes with enhanced virulence.

MATERIAL AND METHODS

This report presents our findings from evaluation of periodontal disease bone defects in skulls from 569 animals (5-31 years of age) derived from the skeletons of the rhesus monkeys (Macaca mulatta) of Cayo Santiago derived from eight matrilines over 6-9 generations. The distance from the base of alveolar bone to the cemento-enamel junction on 1^st /2^nd premolars and 1^st /2^nd molars from all four quadrants was evaluated as a measure of periodontal disease. Additionally, we documented the presence of periodontitis in 79 living descendants within these matrilines.

RESULTS

The results demonstrated an increased extent and severity of periodontitis with aging across all matrilines. Extensive heterogeneity in disease expression was observed among the animals and this was linked to specific periodontitis susceptible matrilines. Moreover, we identified some matrilines in which the members appeared to show some resistance to more severe disease, even with aging.

CONCLUSION

Linking these disease variations to multigenerational matriarchal family units supported familial susceptibility of periodontitis. This familial disease relationship was reinforced by the distribution of naturally-occurring periodontitis in the living descendants.

Genomewide Association Study Identifies Cxcl Family Members as Partial Mediators of LPS-Induced Periodontitis

Periodontitis (PD) is characterized by bacterial infection and inflammation of tooth-supporting structures and can lead to tooth loss. PD affects ∼47% of the US population over age 30 years and has a heritability of about 50%. Although the host immunoinflammatory response and genetic background play a role, little is known of the underlying genetic factors. We examined natural genetic variation in lipopolysaccharide (LPS)-induced PD across a panel of inbred mouse strains, the hybrid mouse diversity panel (HMDP). We observed a strain-dependent sixfold difference in LPS-induced bone loss across the HMDP with a heritability of 53%. We performed a genomewide association study (GWAS) using FAST-LMM, which corrects for population structure, and identified loci significantly associated with PD. We examined candidate genes at a locus on chromosome 5, which suggested a relationship between LPS-induced bone loss and, together with expression data, identified Cxcl family members as associated with PD. We observed an increase in Cxcl10 protein, as well as immune cells and pro-inflammatory cytokines in C57BL/6J (high bone loss strain) but not in A/J (low bone loss strain) after LPS injections. Genetic deletion of CXCR3 (Cxcl9 and10 receptor) demonstrated a ∼50% reduction in bone loss and reduced osteoclasts after LPS injections. Furthermore, WT mice treated with AMG-487 (a CXCR3 antagonist) showed a ∼45% reduction in bone loss and decreased osteoclasts after LPS injections. We conclude that CXCR3 is a strong candidate for modulating the host response in individuals susceptible to PD. © 2018 American Society for Bone and Mineral Research.

Revisiting the Page & Schroeder model: the good, the bad and the unknowns in the periodontal host response 40 years later

In their classic 1976 paper, Page & Schroeder described the histopathologic events and the types of myeloid cells and lymphocytes involved in the initiation and progression of inflammatory periodontal disease. The staging of periodontal disease pathogenesis as 'initial', 'early', 'established' and 'advanced' lesions productively guided subsequent research in the field and remains fundamentally valid. However, major advances regarding the cellular and molecular mechanisms underlying the induction, regulation and effector functions of immune and inflammatory responses necessitate a reassessment of their work and its integration with emerging new concepts. We now know that each type of leukocyte is actually represented by functionally distinct subsets with different, or even conflicting, roles in immunity and inflammation. Unexpectedly, neutrophils, traditionally regarded as merely antimicrobial effectors in acute conditions and protagonists of the 'initial' lesion, are currently appreciated for their functional versatility and critical roles in chronic inflammation. Moreover, an entirely new field of study, osteoimmunology, has emerged and sheds light on the impact of immunoinflammatory events on the skeletal system. These developments and the molecular dissection of crosstalk interactions between innate and adaptive leukocytes, as well as between the immune system and local homeostatic mechanisms, offer a more nuanced understanding of the host response in periodontitis, with profound implications for treatment. At the same time, deeper insights have generated new questions, many of which remain unanswered. In this review, 40 years after Page & Schroeder proposed their model, we summarize enduring and emerging advances in periodontal disease pathogenesis.

Association between Apical Periodontitis and Interleukin Gene Polymorphisms: A Systematic Review and Meta-analysis

INTRODUCTION

Genetic polymorphisms may result in altered gene expression or functional changes of the encoded molecules and could possibly generate a deficient immunity. Consequently, individuals with specific genotypes could be more susceptible to disease or could present an increase in disease severity. Our study is aimed to verify, through a systematic review and meta-analysis registered in the PROSPERO database (CRD42016043905), whether currently available evidence supports a relationship between interleukin gene polymorphisms and apical periodontitis (AP).

METHODS

A broad search for studies was conducted. The following databases were used: PubMed, Scopus, Web of Science, and the Virtual Health Library (MEDLINE, SciELO, IBECS, and LILACS). The Medical Subject Headings (MeSH) terms "Periapical Periodontitis," "Periapical Abscess," "Polymorphism, Genetic," and "Polymorphism, Single Nucleotide" were used. MeSH synonyms, related terms, and free terms were included. After application of the eligibility criteria, selected studies were qualified by assessment of their methodologic quality. A fixed effects model was used for the meta-analysis.

RESULTS

The initial search identified 71 references. After excluding duplicate abstracts, 33 were selected. From these, 6 were eligible for quality assessment; 5 were classified as being of moderate quality, and 1 was classified as being of high quality.

CONCLUSIONS

From these included studies, polymorphisms in IL1B, IL6, and IL8 were associated with AP. Polymorphisms in IL1A, IL10, or IL12B were not associated with AP regardless of the methodology used. The meta-analysis suggested that the genotype and allele distribution of IL1B (+3954 C/T) gene polymorphism was different in post-treatment AP. More research in this area is warranted to confirm these results.

Acidification induces OGR1/Ca2+/calpain signaling in gingival fibroblasts

Gingivitis, the mildest form of periodontitis, is generally considered a consequence of prolonged exposure of the gingiva to periodontal pathogens. On the other hand, several epidemiologic reports have suggested that other etiologic factors such as oral acidification may also increase the susceptibility of the periodontium to destruction. However, the pathologic mechanism underlying the effects of oral acidification on the gingiva is still largely unknown. In this study, we analyzed molecular pathways mediating the influence of the acidic environment on human gingival fibroblasts (HGFs). Acidic extracellular pH caused biphasic increase of intracellular Ca²⁺ level ([Ca²⁺]_i) through activation of ovarian cancer G protein-coupled receptor 1, phospholipase C, and Ca²⁺ release from the endoplasmic reticulum, but not through voltage-gated Ca²⁺ channels or extracellular Ca²⁺ influx via transient receptor potential cation channel subfamily V member 1. The acidic environment was also transiently cytotoxic for HGFs; however, the activation of pro-apoptotic proteins poly (ADP-ribose) polymerase-1 and BAX was not observed. Furthermore, we found that intracellular matrix metalloproteinase 1 was consistently upregulated in HGFs grown in regular medium, but significantly reduced in the acidic medium, which depended on [Ca²⁺]_i increase, lysosomal pH homeostasis, and Ca²⁺-dependent protease calpain. Considering that HGFs, essential for oral wound healing, in the in vitro culture system are placed in wound repair-like conditions, our findings provide important insights into molecular mechanisms underlying HGF functional impairment and chronic damage to the gingiva caused by the acidic intraoral environment.

Susceptibility of different mouse strains to peri-implantitis

BACKGROUND AND OBJECTIVE

Peri-implantitis (PI) is an inflammatory condition that affects the tissues surrounding dental implants. Although the pathogenesis of PI is not fully understood, evidence suggests that the etiology is multifactorial and may include a genetic component. The aim of this study was to investigate the role of genetics in the development of peri-implantitis.

MATERIAL AND METHODS

Four-week-old C57BL/6J, C3H/HeJ and A/J male mice had their left maxillary molars extracted. Implants were placed in the healed extraction sockets. Upon osseointegration, ligatures were placed around the implant head for 1 or 4 weeks to induce PI. Micro-computed tomography scanning was used to measure volumetric bone loss. Histological analyses were also performed to evaluate collagen organization and the presence of neutrophils and osteoclasts.

RESULTS

Radiographically, comparing the ligature-treated mice, C57BL/6J displayed the greatest amount of bone loss, followed by C3H/HeJ and A/J mice at 1 and 4 weeks. Histologically, at 1 week, C57BL/6J mice presented with the highest numbers of neutrophils and osteoclasts. At 4 weeks, C57BL/6J mice presented with the most active bone remodeling compared with the other two strains.

CONCLUSION

There were significant differences in the severity of peri-implantitis among the different mouse strains, suggesting that the genetic framework can affect implant survival and success. Future work is needed to dissect the genetic contribution to the development of peri-implantitis.

CCR5Δ32 (rs333) polymorphism is associated with decreased risk of chronic and aggressive periodontitis: A case-control analysis based in disease resistance and susceptibility phenotypes

Chronic and aggressive periodontitis are infectious diseases characterized by the irreversible destruction of periodontal tissues, which is mediated by the host inflammatory immune response triggered by periodontal infection. The chemokine receptor CCR5 play an important role in disease pathogenesis, contributing to pro-inflammatory response and osteoclastogenesis. CCR5Δ32 (rs333) is a loss-of-function mutation in the CCR5 gene, which can potentially modulate the host response and, consequently periodontitis outcome. Thus, we investigated the effect of the CCR5Δ32 mutation over the risk to suffer periodontitis in a cohort of Brazilian patients (total N=699), representative of disease susceptibility (chronic periodontitis, N=197; and aggressive periodontitis, N=91) or resistance (chronic gingivitis, N=193) phenotypes, and healthy subjects (N=218). Additionally, we assayed the influence of CCR5Δ32 in the expression of the biomarkers TNFα, IL-1β, IL-10, IL-6, IFN-γ and T-bet, and key periodontal pathogens P. gingivalis, T. forsythia, and T. denticola. In the association analysis of resistant versus susceptible subjects, CCR5Δ32 mutant allele-carriers proved significantly protected against chronic (OR 0.49; 95% CI 0.29-0.83; p-value 0.01) and aggressive (OR 0.46; 95% CI 0.22-0.94; p-value 0.03) periodontitis. Further, heterozygous subjects exhibited significantly decreased expression of TNFα in periodontal tissues, pointing to a functional effect of the mutation in periodontal tissues during the progression of the disease. Conversely, no significant changes were observed in the presence or quantity of the periodontal pathogens P. gingivalis, T. forsythia, and T. denticola in the subgingival biofilm that could be attributable to the mutant genotype.

Biomarker levels in gingival crevicular fluid of generalized aggressive periodontitis patients after non-surgical periodontal treatment

OBJECTIVES

The aim of this study was to assess the effects of non-surgical periodontal treatment on gingival crevicular fluid (GCF) cytokines in patients with generalized aggressive periodontitis (GAgP), in relation to clinical parameters.

MATERIALS AND METHODS

Data were obtained from 16 GAgP patients and 15 periodontally healthy controls. Periodontal parameters and GCF biomarker levels were evaluated at baseline and repeated 3 and 6 months after treatment for GAgP subjects. Moderate and deep pocket sites were analyzed separately. The amount of interleukin (IL)-1β, IL-9, tumor necrosis factor (TNF)-α, platelet-derived growth factor (PDGF-bb), and vascular endothelial growth factor (VEGF) were measured using a highly specific and sensitive multiplex bead immunoassay.

RESULTS

At baseline, cytokine levels in the moderate and deep pocket sites of GAgP patients were higher than those of the healthy control sites. In GAgP group, periodontal treatment led to improvement in all examined clinical parameters and resulted in a statistically significant reduction in the total amounts of IL-1β, VEGF, and TNF-α, in comparison to baseline, already 3 months after therapy in both moderate and deep pocket sites and of PDGF-bb in deep sites (p < 0.01). At the concentration level, only IL-1β and VEGF were affected.

CONCLUSION

Non-surgical treatment of GAgP provided significant clinical benefits leading to a marked decrease in the GCF levels of some pro-inflammatory and pro-angiogenic cytokines, but not of IL-9 and PDGF-bb.

CLINICAL RELEVANCE

Although the periodontal therapy successfully decreased clinical signs of inflammation, the GCF levels of some inflammatory cytokines were still elevated.

Autologous Platelet-Rich Fibrin in the Treatment of 3-Wall Intrabony Defects in Aggressive Periodontitis: A Randomized Controlled Clinical Trial

BACKGROUND

Platelet-rich fibrin (PRF) has recently been applied in osseous regeneration. The aim of the present study is to explore the efficacy of PRF in treatment of intrabony defects (IBDs) in aggressive periodontitis.

METHODS

Fifty-four IBDs in 17 patients were treated either with autologous PRF with open flap debridement (OFD) or OFD alone. Clinical and radiologic parameters such as probing depth (PD), clinical attachment level (CAL), IBD depth, and percentage defect change were recorded at baseline and 9 months postoperatively.

RESULTS

Mean PD reduction and mean CAL gain were significantly greater in PRF compared with the control group. Furthermore, a significantly greater percentage of mean bone defect change was found in the PRF group.

CONCLUSION

Within the limits of the present study, there is greater bone fill at sites treated with PRF with conventional OFD than conventional OFD alone.

Inducible Nitric Oxide Synthase Polymorphisms and Nitric Oxide Levels in Individuals with Chronic Periodontitis

This study aimed to investigate whether the -1026(A>C)(rs2779249) and +2087(A>G)(2297518) polymorphisms in the NOS2 gene were associated with chronic periodontitis (CP) and with salivary levels of nitrite (NO₂^-) and/or nitrate + nitrite (NOx). A group of 113 mixed-race patients were subjected to periodontal, genetic, and biochemical evaluations (65 CP/48 periodontally healthy subjects). DNA was extracted from oral epithelial cells and used for genotyping by polymerase chain reaction (real-time). Salivary NOx concentrations were determined using an ozone-based chemiluminescence assay. Association of CP with alleles and genotypes of the -1026(A>C) polymorphism was found (X² test, p = 0.0075; 0.0308), but this was not maintained after multiple logistic regression, performed to estimate the effect of covariates and polymorphisms in CP. This analysis demonstrated, after correction for multiple comparisons, that only the female gender was significantly associated with CP. Polymorphisms analyzed as haplotypes were not associated with CP. NOx levels were significantly higher in the control group of heterozygous individuals for both polymorphisms. In conclusion, the female gender was significantly associated with CP, and higher levels of salivary NOx were found in control subjects and associated with the heterozygous state of the NOS2 polymorphisms, reinforcing the potential of NO metabolites as markers of periodontitis status.

Is there an association between IFN-γ +874A/T polymorphism and periodontitis susceptibility?: A meta-analysis

BACKGROUND

Interferon-γ (IFN-γ) is a key proinflammatory cytokine which plays a critical role in the pathogenesis and progression of periodontitis. The single nucleotide polymorphism of +874A/T in human IFN-γ gene can influence the secretion of IFN-γ and affect periodontitis susceptibility. However, the findings of published studies are inconsistent. Therefore, the goal of this meta-analysis is to investigate whether there is an association between IFN-γ +874A/T polymorphism and periodontitis susceptibility.

METHODS

PubMed and the Cochrane Library were searched for eligible clinical studies. The odds ratio (OR) and 95% confidence interval (CI) of each study were pooled to estimate the strength of association between +874A/T and periodontitis. Subgroup analyses were performed to explore whether particular characteristics of studies were related to the overall results.

RESULTS

Seven studies and a total of 1252 periodontitis patients and 1622 periodontitis-free control subjects were included. No difference was observed in genotype distribution and allele frequency between periodontitis patients and control (T vs A: OR  =  1.01, 95% CI: 0.90-1.13, P  =  .878; TT vs AA: OR  =  1.07, 95% CI: 0.87-1.32, P  =  .537; AT vs AA: OR  =  1.00, 95% CI: 0.81-1.23, P  =  .996; TT+AT vs AA: OR  =  1.00, 95% CI: 0.84-1.19, P  =  .990; TT vs AA+AT: OR  =  1.03, 95% CI: 0.86-1.23, P  =  .733). Besides, the subgroup analysis based on ethnicity, type of periodontitis, and smoking status failed to identify significant differences in each model, either.

CONCLUSIONS

The results of this meta-analysis suggest that IFN-γ +874 A/T polymorphism may not contribute to periodontitis susceptibility. High quality and well-designed studies which combine genetic and other environmental risk factors are needed to validate this conclusion in the future.

[Therapeutic effect of enhancer of Zeste homolog 2 inhibitor GSK343 on periodontitis by regulating macrophage differentiation]

OBJECTIVE

To explore the therapeutic effect of enhancer of Zeste homolog 2 (EZH2) inhibitor GSK343 on periodontitis by regulating microphage differentiation.

METHODS

Macrophage RAW264.7 cells were divided into the blank (A group), control (B group), lipopolysaccharide (LPS) stimulation (C group), and LPS+GSK343 (D group) groups. Phenotype transformations was determined through Western blot analysis and enzyme-linked immunosorbent assay by detecting the differentiation of phenotypic biological markers, including tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), interleukin-10 (IL-10), and Arginase-1 (Arg-1). Metergasis was identified by performing a phagocytosis test on Escherichia coli (E. coli).

RESULTS

Macrophage RAW264.7 cells produced classical phenotypic biomarkers (M1) TNF-α and iNOS under LPS stimulation. The expression levels of IL-10 and Arg-1 increased after adding GSK343 into the culture medium. GSK343 also induced the conversion of M1 macrophages into M2 macrophages. Macrophage RAW264.7 cells exerted a phagocytic effect on E. coli, and this effect was enhanced after adding LPS into the culture medium. GSK343 regulated the macrophage RAW264.7 phagocytosis of E. coli.

CONCLUSIONS

GSK343 possibly participates in the regulation of macrophage differentiation and, consequently, in the latent treatment of periodontitis.

RANK/RANKL/OPG Signalization Implication in Periodontitis: New Evidence from a RANK Transgenic Mouse Model

Periodontitis is based on a complex inflammatory over-response combined with possible genetic predisposition factors. The RANKL/RANK/OPG signaling pathway is implicated in bone resorption through its key function in osteoclast differentiation and activation, as well as in the inflammatory response. This central element of osteo-immunology has been suggested to be perturbed in several diseases, including periodontitis, as it is a predisposing factor for this disease. The aim of the present study was to validate this hypothesis using a transgenic mouse line, which over-expresses RANK (R^Tg) and develops a periodontitis-like phenotype at 5 months of age. R^Tg mice exhibited severe alveolar bone loss, an increased number of TRAP positive cells, and disorganization of periodontal ligaments. This phenotype was more pronounced in females. We also observed dental root resorption lacunas. Hyperplasia of the gingival epithelium, including Malassez epithelial rests, was visible as early as 25 days, preceding any other symptoms. These results demonstrate that perturbations of the RANKL/RANK/OPG system constitute a core element of periodontitis, and more globally, osteo-immune diseases.