Interleukin-17A Gene Variability in Patients with Type 1 Diabetes Mellitus and Chronic Periodontitis: Its Correlation with IL-17 Levels and the Occurrence of Periodontopathic Bacteria

Relationship Between Diabetes Mellitus and Periodontal/Peri-Implant Disease: A Contemporaneous Review

The prevalence of diabetes mellitus (DM), a major chronic disease and a leading cause of death and disability around the world, is rising. According to the latest data, the global prevalence of DM has increased to 463 million (9.3% of adults) in 2019 and is estimated to reach 700 million by 2045. Periodontal disease, result of periodontium inflammation, is a common, chronic disease and has long been considered one of the complications of DM. Moreover, literature reflects a spectrum of conflicting viewpoints on the effect of diabetic conditions on the implant treatment strategies. The current review aims to update the recent epidemiologic evidence regarding the relationship between DM and periodontal/peri-implant disease, emphasising the effects of glycaemic control on the severity of these diseases and describing the pathobiological mechanisms underlying this association. This review's findings indicate a bidirectional relationship between DM and periodontal/peri-implant disease and that this relationship seems causal, implying that controlling these two diseases might help prevent each other's incidence. Additionally, the severity of periodontal/peri-implant disease is directly related to metabolic control. Although patients with diabetes can obtain implant success similar to those in systemically healthy individuals, an increased risk of peri-implantitis has been reported in DM patients. Therefore, the importance of glycaemic control and maintaining proper oral hygiene cannot be overstated.

Salivary interleukin-17A and interleukin-18 levels in patients with celiac disease and periodontitis

Background

An increased level of interleukin-17A and interleukin-18 in the serum and intestinal mucosa of celiac disease patients reflecting the severity of villous atrophy and inflammation was documented. Thus, the objective of this study was to evaluate the concentrations of salivary-17A, interleukin-1 beta, and interleukin-18 in patients with celiac disease who are on a gluten-free diet, both with and without periodontitis, and to compare these levels with those in healthy individuals.

Methods

The study involved 23 participants with serologically confirmed celiac disease (CD) and 23 control subjects. The CD patients had been following a gluten-free diet (GFD) for a minimum of 1 year and had no other autoimmune disorders. The research involved collecting demographic data, conducting periodontal examinations, gathering unstimulated whole saliva, and performing enzyme-linked immunosorbent assays to measure salivary interleukin-17A, interleukin-1 beta, and interleukin-18 levels. Spearman's correlation analysis was utilized to explore the relationships between CD markers in patients on a GFD and their periodontal clinical findings.

Results

The periodontal findings indicated significantly lower values in celiac disease patients adhering to a gluten-free diet compared to control subjects (p = 0.001). No significant differences were found in salivary IL-17A, IL-18, and IL-1B levels between celiac disease patients and control subjects. Nevertheless, the levels of all interleukins were elevated in periodontitis patients in both the celiac and control groups. The IL-1 Beta level was significantly higher in periodontitis patients compared to non-periodontitis patients in the control group (p = 0.035). Significant negative correlations were observed between serum IgA levels and plaque index (r = -0.460, p = 0.010), as well as gingival index (r = -0.396, p = 0.030) in CD patients on a gluten-free diet.

Conclusion

Celiac disease patients on gluten-free diet exhibited better periodontal health compared to control subjects. However, increased levels of salivary IL-17A, IL-18 and IL-1B levels were associated with periodontitis. Additionally, serum IgA level was significantly inversely associated with periodontitis clinical manifestations and with salivary inflammatory mediators in CD patients on GFD.

Characterization of the oral microbiome of children with type 1 diabetes in the acute and chronic phases

Background and Aim

The relationship between the oral microbiota and type 1 diabetes (T1D) remains unclear. We aimed to evaluate the variations in the oral microbiome in T1D and identify potentially associated bacterial factors.

Methods

We performed high-throughput sequencing of the V3-V4 area of the 16S rRNA gene to profile the oral bacterial composition of 47 healthy children (CON group), 46 children with new-onset T1D in the acute phase (NT1D group), and 10 children with T1D in the chronic phase receiving insulin treatment (CT1D group). Multivariate statistical analysis of sequencing data was performed.

Results

Compared to the CON group, the NT1D group was characterized by decreased diversity and increased abundance of genera harboring opportunistic pathogens, while this trend was partially reversed in the CT1D group. Differential genera between groups could distinguish the NT1D group from the CON group (AUC = 0.933) and CT1D group (AUC = 0.846), respectively. Moreover, T1D-enriched genera were closely correlated with HbA1c, FBG and WBCs levels.

Conclusion

Our results showed that the acute phase of T1D was characterized by oral microbiota dysbiosis, which could be partially ameliorated via glycemic control. The possible role of oral microbiota dysbiosis on oral health and systemic metabolic status in T1D warrants further mechanistic investigation.

Gut microbiota dysbiosis as an inflammaging condition that regulates obesity-related retinopathy and nephropathy

Diabetes-specific microvascular disease is a leading cause of blindness, renal failure and nerve damage. Epidemiological data demonstrated that the high morbidity of T2DM occurs as a result of obesity and gradually develops into serious complications. To date, the mechanisms that underlie this observation are still ill-defined. In view of the effect of obesity on the gut microflora, Lepr^db/db mice underwent antibiotic treatment and microbiota transplants to modify the gut microbiome to investigate whether microbes are involved in the development of diabetic nephropathy (DN) and/or diabetic retinopathy (DR). The mouse feces were collected for bacterial 16S ribosomal RNA gene sequencing. Cytokines including TNF-α, TGF-β1, IFN-γ, IL-1β, IL-6, IL-17A, IL-10, and VEGFA were detected by enzyme-linked immunosorbent assay (ELISA), flow cytometry, real-time PCR and immunofluorescent assay. Eyes and kidney were collected for histopathological assay. Intestinal permeability was also detected using Evans Blue. The results showed that obesity influenced metabolic variables (including fast/fed glucose, insulin, and triglyceride), retinopathy and nephropathy, and the gut microbiota. Obesity mainly reduced the ratio of Bacteroidetes/Firmicutes and influenced relative abundance of Proteobacteria, Actinobacteria, and Spirochetes. Obesity also increased intestinal permeability, metabolic endotoxemia, cytokines, and VEGFA. Microbiota transplants confirm that obesity aggravates retinopathy and nephropathy through the gut microbiota. These findings suggest that obesity exacerbates retinopathy and nephropathy by inducing gut microbiota dysbiosis, which further enhanced intestinal permeability and chronic low-grade inflammation.

The relationship between B-cell lymphoma 2, interleukin-1β, interleukin-17, and interleukin-33 and the development of diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is among the main complications of diabetes mellitus and has been a major factor of renal failure. This study was designed to address the association between beta-cell lymphoma-2 (Bcl-2), interleukin (IL)-1β, IL-17, and IL-33 and the development of DN.

METHODS

In this study, 20 healthy volunteers and 100 patients were enrolled. According to their biochemical markers, the patients were categorized into five groups: diabetic, chronic renal disease, diabetic chronic renal disease, end-stage renal disease, and diabetic end-stage renal disease.

RESULTS

Our results showed a noticeable elevation in IL-1β and IL-17 levels and a reduction in IL-33 and Bcl-2 levels in all investigated groups compared with those in the healthy group. Positive correlations were found between IL-1β and fasting blood sugar and between creatinine levels and IL-17, HbA1c%, and sodium levels. However, negative correlations were found between IL-33 and urea and sodium concentrations and between Bcl-2 and HbA1c% and creatinine levels.

CONCLUSIONS

The present data revealed a marked relationship between Bcl-2, IL-1β, IL-17, and IL-33 levels and the onset and progression of DN. Understanding the molecular pathways of these processes could be translated into the development of therapeutic strategies.

Periodontal infectogenomics: a systematic review update of associations between host genetic variants and subgingival microbial detection

Objective

The aim of this study was to systematically update the evidence for associations between host genetic variants and subgingival microbial detection and counts.

Materials and methods

Following a previous systematic review (Nibali et al. J Clin Periodontol 43(11): 889-900, 15), an update of a systematic search of the literature was conducted in Ovid Medline, Embase, LILACS, and Cochrane Library for studies reporting data on host genetic variants and detection of microbes subgingivally published in the last 6 years.

Results

A total of 19 studies were included in the review, from an initial search of 2797 titles. Studies consisted mainly of candidate gene studies and of one genome-wide analysis. A total of 62 studies were considered for summary findings, including 43 identified in the previous systematic review of studies published up to 2015. Meta-analyses were done when appropriate including both papers in the original review and in the update. Meta-analyses revealed lack of associations between IL1 composite genotype and subgingival detection of Aggregatibacter acinomycetemcomitans, Poprhyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Prevotella intermedia. Promising evidence is emerging from other genetic variants and from sub-analyses of data from genome-association studies. Among other studies with candidate-gene, target SNPs were mainly within the IL10, IL6, IL4, IL8, IL17A, and VDR gene.

Conclusions

IL1 composite genotype does not seem to be associated with subgingival microbial detection. Promising associations should be pursued by future studies, including studies employing -OMICS technologies.

Clinical relevance

A better knowledge of which host genetic variant predispose to subgingival microbial colonization and to the development of progression of periodontal disease could potentially help to better understand periodontal disease pathogenesis and help with its management.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-021-04233-8.

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

Aim

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

Material and Methods

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

Results

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

Conclusion

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

Association of IL-17A Polymorphism with Chronic Periodontitis in Type 1 Diabetic Patients

STATEMENT OF THE PROBLEM

The association of genetic polymorphisms with periodontitis has been studied extensively. The interleukin -17 (IL-17) is a group of cytokines, which comprises six different molecules (IL-17A, B, C, D, E & F). Among these, IL-17A & F are the most commonly understood cytokine, which plays a critical role in inflammatory diseases and periodontal inflammation.

PURPOSE

To evaluate whether IL-17A gene polymorphism is associated with increased risk of chronic periodontitis in type 1 diabetes patients.

MATERIALS AND METHOD

This quantitative case- control study was carried out in 60 subjects in 4 groups. The study groups included group A: 15 type 1 diabetes patients (T1DM) with chronic periodontitis (CP), group B: 15 T1DM patients without CP, group C: 15 Non-diabetic patients with CP, group D: 15 Non-diabetic patients without CP. Blood samples were drawn from the subjects and analyzed for IL-17A polymorphism by using the polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

There was no statistical significant difference seen in the genotype distribution among CP patients with or without T1DM and healthy controls. Odds ratio and p value indicated that increased risks for CP were associated with IL-17A allele (G) in patients with T1DM. This allele was correlated with worse clinical parameters of CP in T1DM patients.

CONCLUSION

The present study revealed that IL-17A (rs2275913) polymorphism was not associated with increased risk for CP in T1DM patients.

Polymorphisms and haplotypes in the Interleukin 17 Alfa gene: potential effect of smoking habits in the association with periodontitis and type 2 diabetes mellitus

Few studies evaluate interrelationships between periodontitis (P) and Type 2 Diabetes Mellitus (T2DM). The aim of this study is to investigate the genetic susceptibility to periodontitis alone, or concomitant with T2DM (as comorbidities), analyzing single nucleotide polymorphisms (SNPs) in the Interleukin 17 alpha (IL17A) gene, considering the biochemical profile and smoking habits on the subjects' periodontal status. We investigated 879 individuals divided into: T2DM subjects also affected by severe or moderate periodontitis (T2DM-P, n = 199); non-diabetics with severe or moderate periodontitis (PERIODONTITIS, n = 342); and healthy subjects (HEALTHY, n = 338). Subjects underwent complete periodontal examination, history of smoking habits, glycemic and lipid biochemical evaluation. DNA from buccal cells was utilized to genotype the SNPs rs2275913, rs3819024 and rs10484879. The impact of the subjects' biochemical profile was analyzed in their periodontal status. Each SNP was analyzed independently, and as haplotypes, by multiple logistic regressions, adjusted for covariates, and also stratifying the groups by age, sex and smoking habits. Independently of the periodontitis degree, poorly-controlled T2DM subjects showed worse glycemic and lipid profile. Multiple logistic regressions demonstrated that smokers and former-smokers carrying the GG genotype of rs3819024 seemed to have higher risk for T2DM-Periodontitis (OR = 6.33; 95% CI = 1.26-31.77, p = 0.02), and mainly for T2DM alone (OR = 5.11; 95% CI = 1.37-19.06, p = 0.01), than never smokers. We found the potential effect of smoking habits in the association of IL17A-rs3819024-GG with diseased phenotypes. Because the observed wide confidence intervals, further studies enrolling larger populations, and SNPs' functional evaluations are needed to better understand our findings.

IL-17F Gene rs763780 and IL-17A rs2275913 Polymorphisms in Patients with Periodontitis

Background: Periodontitis (PD) is a chronic inflammatory disease that can eventually lead to tooth loss. Genetic and environmental factors such as smoking are involved in the pathogenesis of PD. The development of PD is potentiated by various pathogens that induce an immune response leading to the production of cytokines, such as interleukin (IL)-17. The synthesis of IL-17 is influenced genetically. The polymorphisms in IL-17 gene may affect the synthesis of IL-17. The aim of this study was to examine the association between the IL-17F rs763780 and IL-17A rs2275913 polymorphisms and PD in non-smoking and smoking patients to check if these polymorphisms could be a risk factor for PD. Methods: The study enrolled 200 patients with PD (130 non-smokers and 70 smokers) and 160 control subjects (126 non-smokers and 34 smokers). Periodontitis was diagnosed on the basis of 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. All samples were genotyped using allelic discrimination assays with TaqMan® probes on a Real-Time PCR Detection System. Results: There were no statistically significant differences in the distribution of the IL-17F rs763780 and IL-17A rs2275913 genotypes and alleles between patients with PD and control subjects, between smoking patients with PD and smoking control subjects, and between non-smoking patients with PD and non-smoking control subjects. Conclusions: The results of this study suggest a lack of statistically significant associations between IL-17F rs763780 and IL-17A rs2275913 polymorphisms and PD in Polish population.

Cytokines and Their Genetic Polymorphisms Related to Periodontal Disease

Periodontal disease (PD) is a chronic inflammatory disease caused by the accumulation of bacterial plaque biofilm on the teeth and the host immune responses. PD pathogenesis is complex and includes genetic, environmental, and autoimmune factors. Numerous studies have suggested that the connection of genetic and environmental factors induces the disease process leading to a response by both T cells and B cells and the increased synthesis of pro-inflammatory mediators such as cytokines. Many studies have shown that pro-inflammatory cytokines play a significant role in the pathogenesis of PD. The studies have also indicated that single nucleotide polymorphisms (SNPs) in cytokine genes may be associated with risk and severity of PD. In this narrative review, we discuss the role of selected cytokines and their gene polymorphisms in the pathogenesis of periodontal disease.

Oral P. gingivalis impairs gut permeability and mediates immune responses associated with neurodegeneration in LRRK2 R1441G mice

Background

The R1441G mutation in the leucine-rich repeat kinase 2 (LRRK2) gene results in late-onset Parkinson’s disease (PD). Peripheral inflammation and gut microbiota are closely associated with the pathogenesis of PD. Chronic periodontitis is a common type of peripheral inflammation, which is associated with PD. Porphyromonas gingivalis (Pg), the most common bacterium causing chronic periodontitis, can cause alteration of gut microbiota. It is not known whether Pg-induced dysbiosis plays a role in the pathophysiology of PD.

Methods

In this study, live Pg were orally administrated to animals, three times a week for 1 month. Pg-derived lipopolysaccharide (LPS) was used to stimulate mononuclear cells in vitro. The effects of oral Pg administration on the gut and brain were evaluated through behaviors, morphology, and cytokine expression.

Results

Dopaminergic neurons in the substantia nigra were reduced, and activated microglial cells were increased in R1441G mice given oral Pg. In addition, an increase in mRNA expression of tumor necrosis factor (TNF-α) and interleukin-1β (IL-1β) as well as protein level of α-synuclein together with a decrease in zonula occludens-1 (Zo-1) was detected in the colon in Pg-treated R1441G mice. Furthermore, serum interleukin-17A (IL-17A) and brain IL-17 receptor A (IL-17RA) were increased in Pg-treated R1441G mice.

Conclusions

These findings suggest that oral Pg-induced inflammation may play an important role in the pathophysiology of LRRK2-associated PD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-020-02027-5.

External apical root resorption in orthodontic patients: molecular and genetic basis

External apical root resorption is one of the most deleterious complications after orthodontic treatment. Studies to explain the causal relationship between orthodontic tooth movement and external apical root resorption have been inconclusive till date. Individual variations in external apical root resorption sometimes overshadow the treatment related factors which indicate genetic predisposition and/or multifactorial etiology. Mechanism of root resorption is not completely understood. Inflammatory root resorption induced by orthodontic treatment is a part of process of elimination of hyaline zone. An imbalance between bone resorption and deposition may contribute to root resorption by the cementoclasts/osteoclasts. This narrative review article explains the molecular pathway involved in external apical root resorption and also role of various genes involved at different level. It also reviews the literature published during the past 20 years concerning the association studies linking EARR to genetic polymorphisms. This literature review provides an insight into genetic predisposition of external apical root resorption that can be used in orthodontic practice to enable 'high-risk' subjects to be identified on the basis of their genetic information before orthodontic treatment is initiated.

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.

Microbes as Master Immunomodulators: Immunopathology, Cancer and Personalized Immunotherapies

The intricate interplay between the immune system and microbes is an essential part of the physiological homeostasis in health and disease. Immunological recognition of commensal microbes, such as bacterial species resident in the gut or lung as well as dormant viral species, i.e., cytomegalovirus (CMV) or Epstein-Barr virus (EBV), in combination with a balanced immune regulation, is central to achieve immune-protection. Emerging evidence suggests that immune responses primed to guard against commensal microbes may cause unexpected pathological outcomes, e.g., chronic inflammation and/or malignant transformation. Furthermore, translocation of immune cells from one anatomical compartment to another, i.e., the gut-lung axis via the lymphatics or blood has been identified as an important factor in perpetrating systemic inflammation, tissue destruction, as well as modulating host-protective immune responses. We present in this review immune response patterns to pathogenic as well as non-pathogenic microbes and how these immune-recognition profiles affect local immune responses or malignant transformation. We discuss personalized immunological therapies which, directly or indirectly, target host biological pathways modulated by antimicrobial immune responses.

Meta-Analysis of Risk Association between Interleukin-17A Gene Polymorphism and Chronic Periodontitis

The association of genetic polymorphisms with periodontitis has been studied extensively. The interleukin-7 (IL-17) is a group of cytokines, which comprises six different molecules (IL-17A, B, C, D, E, and F). Among this, IL-17A is the most commonly understood cytokine, and its polymorphism plays a critical role in inflammatory diseases and periodontal inflammation. The present study was aimed at pooling the data available for meta-analysis and to evaluate whether IL-17A (rs2275913) polymorphism is associated with the susceptibility of chronic periodontitis.

Association of A-197G polymorphism in interleukin-17 gene with chronic periodontitis: Evidence from six case-control studies with a computational biology approach

AIM

The aim of the present study was to evaluate the association of interleukin-17 (IL-17) A-197G gene polymorphism with chronic periodontitis (CP) in a case-control study, a meta-analysis, and an in silico approach.

METHODS

In the case-control study, 122 cases with CP and 126 healthy controls were recruited; IL-17 A-197G genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. In the meta-analysis, comprehensive literature retrieval was performed on valid databases to identify relevant studies. Bioinformatics tools were employed to investigate the effects of A-197G transition on the promoter region of IL-17.

RESULTS

Our case-control study revealed a significant association between IL-17 A-197G transition and CP. The overall meta-analysis revealed significant associations between the IL-17 A-197G polymorphism and CP risk in homozygote co-dominant and recessive models. The stratified analysis also showed a statistically significant association between the mentioned transition and CP risk in the Caucasian population. The in silico analysis revealed that the A-197G polymorphism could make changes in protein-binding sites of the IL-17 promoter region.

CONCLUSIONS

Our study supports that IL-17 A-197G transition could be a genetic risk factor for CP. However, further studies with a larger sample size among different ethnicities are required to obtain a more accurate conclusion.

Distal Consequences of Oral Inflammation

Periodontitis is an incredibly prevalent chronic inflammatory disease, which results in the destruction of tooth supporting structures. However, in addition to causing tooth and alveolar bone loss, this oral inflammatory disease has been shown to contribute to disease states and inflammatory pathology at sites distant from the oral cavity. Epidemiological and experimental studies have linked periodontitis to the development and/or exacerbation of a plethora of other chronic diseases ranging from rheumatoid arthritis to Alzheimer's disease. Such studies highlight how the inflammatory status of the oral cavity can have a profound impact on systemic health. In this review we discuss the disease states impacted by periodontitis and explore potential mechanisms whereby oral inflammation could promote loss of homeostasis at distant sites.

Chemokine Receptor 2 (CXCR2) Gene Variants and Their Association with Periodontal Bacteria in Patients with Chronic Periodontitis

Periodontitis, an inflammatory disease caused by subgingival Gram-negative (G-) bacteria, is linked with loss of the connective tissue and destruction of the alveolar bone. In the regulation of inflammatory response, chemokine receptor 2 (CXCR2), a specific receptor for interleukin-8 and neutrophil chemoattractant, plays an important role. The first aim of this study was to investigate the CXCR2 gene variability in chronic periodontitis (CP) patients and healthy nonperiodontitis controls in the Czech population. The second aim was to find a relation between CXCR2 gene variants and the presence of periodontal bacteria. A total of 500 unrelated subjects participated in this case-control study. 329 CP patients and 171 healthy nonperiodontitis controls were analyzed using polymerase chain reaction techniques for three single-nucleotide polymorphisms (SNPs): +785C/T (rs2230054), +1208T/C (rs1126579), and +1440A/G (rs1126580). A DNA microarray detection kit was used for the investigation of the subgingival bacterial colonization, in a subgroup of CP subjects (N = 162). No significant differences in allele, genotype, haplotype, or haplogenotype frequencies of CXCR2 gene variants between patients with CP and healthy controls (P > 0.05) were determined. Nevertheless, Aggregatibacter actinomycetemcomitans was detected more frequently in men positive for the C allele of the CXCR2 +785C/T polymorphism (61.8% vs. 41.1%, P < 0.05; OR = 2.31, 95% CI = 1.03-5.20) and for the T allele of the CXCR2 +1208C/T variant (61.8% vs. 38.9%, P < 0.05; OR = 2.54, 95% CI = 1.13-5.71). In contrast, no statistically significant associations of CXCR2 variants with seven selected periodontal bacteria were found in women. Although none of the investigated SNPs in the CXCR2 gene was associated with CP, the CXCR2 gene variants can be associated with subgingival colonization of G- bacteria in men with CP in the Czech population.

Interleukin-1 Gene Variability and Plasma Levels in Czech Patients with Chronic Periodontitis and Diabetes Mellitus

Recent studies have suggested a bidirectional relationship between chronic periodontitis (CP) and diabetes mellitus (DM). Immunoregulatory factors such as cytokines play an important role in etiopathogenesis of both diseases. The aim of this study was to analyze variability in interleukin-1 (IL-1) gene cluster and IL-1β plasma levels in patients with CP, DM, and a combination of both diseases. A total of 1016 individuals participating in this case-control study—225 healthy controls, 264 patients with CP, 132 with type 1 diabetes (T1DM), and 395 patients with type 2 diabetes (T2DM)—were genotyped using methods based on polymerase chain reaction for IL-1 gene polymorphisms (IL-1A (−889C/T, rs1800587), IL-1B (+3953C/T, rs1143634), and IL-1RN (gene for IL-1 receptor antagonist, IL-1RA, 86 bp tandem repeats in intron 2)). Levels of IL-1β were measured by Luminex methods in subgroups of controls, CP, T1DM + CP, and T2DM + CP subjects. Although no significant associations were found in the genotype and allele frequencies of IL-1A (−889C/T), significant differences in the allele frequencies of IL-1B (+3953C/T) were observed between controls and CP patients (P < 0.05). In T1DM patients, IL-1RN^∗S “short” allele and IL-1RN 12 genotype were significantly less frequent than those in controls (P < 0.01). In haplotype analysis, TTL haplotype decreased the risk of CP development (P < 0.01), whereas CCS and CTL haplotypes (P < 0.01 and P < 0.05) were associated with T1DM. Although IL-1β levels were measured significantly higher in mononuclear cells after stimulation by mitogens, HSP70, or selected periodontal bacteria than in unstimulated cells, IL-1 genotypes did not correlate with circulating IL-1β levels. In the Czech population, significant associations between the IL-1B polymorphism with CP and the IL-1RN variant with T1DM were found. Haplotype analysis suggests that variability in IL-1 gene cluster may be one of the factors in the CP and T1DM pathogenesis, although single variants of these polymorphisms are not substantial for protein production.

Evaluation of IL-17A, IL-17F, IL-23R, VDR, CCL2, CCL5, CCR2, and CCR5 gene polymorphisms and expression in Chinese individuals with syphilis

Syphilis is a sexually transmitted disease caused by the infection of Treponema pallidum subspecies pallidum. T-helper type 17-related genes, vitamin D receptor (VDR) gene, and chemokine/chemokine receptor genes are crucial in microbial infection. A total of 16 single-nucleotide polymorphisms (SNPs) in eight genes (interleukin [IL]-17A, IL-17F, IL-23R, VDR, C-C motif chemokine ligand [CCL] 2, CCL5, C-C chemokine receptor [CCR] 2, and CCR5) were analyzed in 188 patients with syphilis and 216 healthy controls. The results showed a strong correlation of IL-17A rs2275913 (AA vs AG + GG: odds ratio [OR], 1.78; 95% confidence interval [CI], 1.09 to 2.92; P = 0.020; A vs G: OR, 1.33; 95% CI, 1.01 to 1.76; P = 0.043) and rs3819024 (GG vs AA + GA: OR, 1.76; 95% CI, 1.06 to 2.91; P = 0.028; G vs A: OR, 1.36; 95% CI, 1.03 to 1.80; P = 0.030) with syphilis. In haplotype analysis, IL-17A rs2275913A/rs3819024G showed a risk effect (OR, 1.38; 95% CI, 1.04 to 1.82; P = 0.026), whereas IL-17A rs2275913G/rs3819024A showed a protective effect (OR, 0.76; 95% CI, 0.57 to 0.998; P = 0.048). The expression levels of IL-17A messenger RNA (mRNA) in peripheral blood mononuclear cells and IL-17A secretion in plasma were further examined. No significant differences were found between patients with syphilis and healthy controls. The study also explored whether IL-17A rs2275913 and rs3819024 were associated with the expression of IL-17A mRNA and IL-17A secretion in patients with syphilis. Similar negative results were found. In conclusion, the polymorphisms of IL-17A rs2275913 and rs3819024 and the haplotype containing these two SNPs influenced the susceptibility to syphilis in a Han Chinese population.

The potential pathogenic role of IL-17/Th17 cells in both type 1 and type 2 diabetes mellitus

Diabetes mellitus (DM) is a serious medical problem affecting millions of peoples worldwide, and has a great socio-economic impacts. Cytokines possess a pivotal role in modulation of immune reactions and disease pathogenesis. T-helper type 17 (Th17) cells, an important proinflammatory CD4⁺ T cell subset secreting interleukin 17 (IL-17), has been embroiled in development of DM. There are recent evidences supporting a definitive role of Th17 cells in the etiology of type 1 diabetes (T1D). In addition, IL-17 has been shown to play a crucial role in inflammation, insulin resistance, and type 2 diabetes (T2D). Recently, small molecules which have been specified to block Th17 cells differentiation are considered as potential therapeutics for the disease. Anti-IL-17 neutralizing antibodies and/or antibodies targeting Th17 cells have been investigated to protect individuals at risk from disease development. In this review we aimed to shed light on the potential role of IL-17 and Th17 cells in both T1D and T2D pathogenesis and future therapeutic strategies.

Autoimmune Diseases and Oral Health: 30-Year Follow-Up of a Swedish Cohort

Oral infections up-regulate a number of systemic inflammatory reactions that, in turn, play a role in the development of systemic diseases. We investigated the association between oral health and autoimmune diseases in a cohort of Swedish adults. Hypothesis was that poor oral health associates with incidence of autoimmune diseases. Overall 1676 subjects aged 30–40 years old from Stockholm County (Sweden) participated in this study in 1985. Subjects were randomly selected from the registry file of Stockholm region and were followed-up for 30 years. Their hospital and open health care admissions (World Health Organization ICD 9 and 10 codes) were recorded from the Swedish national health registers. The association between the diagnosed autoimmune disease and the oral health variables were statistically analyzed. In all, 50 patients with autoimmune diagnoses were detected from the data. Plaque index was significantly higher in the autoimmune disease group (≥median 35 (70%) vs. ˂median 872 (54%), p = 0.030). No statistical difference was found in gingival index, calculus index, missing teeth, periodontal pockets, smoking or snuff use between patients with and without autoimmune disease. Our study hypothesis was partly confirmed. The result showed that subjects with a higher plaque index, marker of poor oral hygiene, were more likely to develop autoimmune diseases in 30 years.

Meta-Analysis of Risk Association Between Interleukin-17A and F Gene Polymorphisms and Inflammatory Diseases

This meta-analysis examined the relationship between IL-17A (rs2275913) and IL17F (rs763780 T/C) gene polymorphisms and the risk of inflammatory diseases, including periodontitis, rheumatoid arthritis (RA), and inflammatory bowel disease. PubMed, MEDLINE, EMBASE, Web of Science, and Elsevier Science Direct were searched, and odds ratios (ORs) with 95% confidence interval (CI) were calculated to estimate the strength of the association. A total of 25 studies comprising 7,474 cases and 10,628 controls were included. Significant associations were found between inflammatory diseases and IL-17A rs2275913 A versus G allele (OR = 1.197, P = 0.033) and the GA versus GG genotype in the codominant model (OR = 1.406, P = 0.036). Our findings suggested that individuals who carry the rs2275913 A allele or GA genotype have a 20% or 41%-increased risk of inflammatory diseases compared with subjects with the G allele or GG genotype, respectively. With respect to IL-17F rs763780, the C versus T allele (OR = 1.94; P = 0.040), the TC versus TT (OR = 1.39; P = 0.041), the CC versus TT (OR = 2.71; P = 0.003), as well as the TC + CC versus TT genotype (OR = 1.83; P = 0.032) were risk factors for RA. In summary, our pooled analysis indicated that the IL-17A (rs2275913) and IL17F (rs763780 T/C) increased the RA risk.

A preliminary study of new single polymorphisms in the T helper type 17 pathway for psoriasis in the Korean population

Psoriasis is a polygenic and multi-factorial disease showing ethnic differences in terms of its severity and frequency. Therapies targeting interleukin (IL)-17A, IL-17 receptor (IL-17R) and Janus kinases (JAKs) are in clinical development for the treatment of psoriasis, and their success suggests the essential role of these molecules in psoriasis. To investigate the genetic susceptibility in T helper type 17 (Th17) cell signal transduction pathways for promoting psoriasis, we performed candidate gene and linkage disequilibrium analysis. In 208 patients and 266 normal controls, we analysed 31 single nucleotide polymorphisms in 12 genes (CAMP, IL17A, IL17F, IL17RA, IL22, JAK1, JAK2, JAK3, STAT3, TLR7, TLR9 and TYK2; abbreviations: CAMP, human cathelicidin antimicrobial peptide; STAT-3, signal transducer and activator of transcription 3; TLR, Toll-like receptor; TYK2, tyrosine kinase 2). Patients with psoriasis showed a strong association for IL17F rs763780 [odds ratio (OR) = 3·27, P = 0·04], which results in a histidine-to-arginine substitution, and JAK2 rs2274471 (OR = 2·66, P = 0·02). In addition, JAK2 rs7849191 showed a protective pattern, met the significance threshold (OR = 0·77, P = 0·05) and showed a tendency for an inverse association with the frequency of early-onset psoriasis under age 40 years (P = 0·07). In haplotype analysis, JAK1 rs310241A/rs2780889T showed a protective effect (OR = 0·73, P = 0·03) in psoriasis. In conclusion, we report two new psoriasis-susceptibility loci, in IL17F and JAK2, as well as a newly identified late-onset associated protective JAK2 locus and a protective JAK1 haplotype in the Korean population.

Tannerella forsythia GroEL induces inflammatory bone resorption and synergizes with interleukin-17

Tannerella forsythia is a major periodontal pathogen, and T. forsythia GroEL is a molecular chaperone homologous to human heat-shock protein 60. Interleukin-17 (IL-17) has been implicated in the pathogenesis of periodontitis and several systemic diseases. This study investigated the potential of T. forsythia GroEL to induce inflammatory bone resorption and examined the cooperative effect of IL-17 and T. forsythia GroEL on inflammatory responses. Human gingival fibroblasts (HGFs) and periodontal ligament (PDL) fibroblasts were stimulated with T. forsythia GroEL and/or IL-17. Gene expression of IL-6, IL-8, and cyclooxygenase-2 (COX-2) and concentrations of IL-6, IL-8, and prostaglandin E₂ (PGE₂ ) were measured by real-time reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assays, respectively. After stimulation of MG63 cells with T. forsythia GroEL and/or IL-17, gene expression of osteoprotegerin (OPG) was examined. After subcutaneous injection of T. forsythia GroEL and/or IL-17 above the calvaria of BALB/c mice, calvarial bone resorption was assessed by micro-computed tomography and histological examination. Tannerella forsythia GroEL induced IL-6 and IL-8 production in HGFs and PDL cells, and IL-17 further promoted IL-6 and IL-8 production. Both T. forsythia GroEL and IL-17 synergistically increased PGE₂ production and inhibited OPG gene expression. Calvarial bone resorption was induced by T. forsythia GroEL injection, and simultaneous injection of T. forsythia GroEL and IL-17 further increased bone resorption. These results suggest that T. forsythia GroEL is a novel virulence factor that can contribute to inflammatory bone resorption caused by T. forsythia and synergizes with IL-17 to exacerbate inflammation and bone resorption.

Genetic determinants and postorthodontic external apical root resorption in Czech children

OBJECTIVE

Genes, involved in the modulation of inflammatory response and bone remodeling, play a role in the development of postorthodontic external apical root resorption (EARR). The aim of our study was to analyze possible associations between seven single nucleotide polymorphisms (SNPs) in interleukin-17A (IL-17), osteopontin (SPP1), purinoreceptor P2X7 (P2RX7), and tumor necrosis factor receptor superfamily member 11B (TNFRSF11B) genes and EARR in children after orthodontic treatment.

SUBJECTS AND METHODS

This case-control study comprised 99 orthodontically treated patients (69 controls and 30 subjects with EARR). Genotype determinations of rs2275913, rs11730582, rs9138, rs208294, rs1718119, rs3102735, and rs2073618 were based on polymerase chain reaction using 5' nuclease TaqMan^® assays.

RESULTS

While no significant differences were observed in allele or genotype frequencies of all seven studied SNPs, specific haplotype of P2RX7 (rs208294 and rs1718119) modified the risk of EARR development (P < 0.05). In addition, the length of treatment with a fixed orthodontic appliance positively correlated with the presence of EARR (P < 0.05).

CONCLUSIONS

Although the effect of individual SNPs studied on the EARR development was not confirmed in the Czech population, complex analysis suggested that variability in the P2RX7 gene and the length of orthodontic treatment may be important factors contributing to the etiopathogenesis of postorthodontic EARR.