Polymorphisms in Genes Involved in Inflammation and Periodontitis: A Narrative Review

Importance of Metalloproteinase 8 (MMP-8) in the Diagnosis of Periodontitis

Periodontitis is a complex condition. Left untreated, it leads to tooth loss and the need for prosthetic treatment. The incidence of periodontitis is steadily increasing, so new methods are being sought to aid in the diagnosis of the disease. Among the methods postulated is the determination of concentrations of bioactive compounds which include extracellular matrix metalloproteinases (MMPs). These enzymes are present in various structural elements of the stomatognathic system. The most promising enzyme of this group appears to be metalloproteinase 8 (MMP-8). MMP-8 assays are performed in gingival fluid or saliva, and MMP-8 levels have been shown to be higher in patients with periodontitis compared to healthy subjects and correlated with some clinical parameters of the condition and the severity of the disease. In addition, the preliminary usefulness of this enzyme in evaluating the effectiveness of periodontal treatment and doxycycline therapy has been demonstrated. Determination of the active form of MMP-8 (aMMP-8) in oral rinse fluid using off-the-shelf assays shows the highest potential. Despite reports about aMMP-8 and promising data on the role of MMP-8 in periodontal diagnosis, a clear determination of the usefulness of this enzyme requires further research.

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.

Roles of ubiquitin-specific proteases in inflammatory diseases

Ubiquitin-specific proteases (USPs), as one of the deubiquitinating enzymes (DUBs) families, regulate the fate of proteins and signaling pathway transduction by removing ubiquitin chains from the target proteins. USPs are essential for the modulation of a variety of physiological processes, such as DNA repair, cell metabolism and differentiation, epigenetic modulations as well as protein stability. Recently, extensive research has demonstrated that USPs exert a significant impact on innate and adaptive immune reactions, metabolic syndromes, inflammatory disorders, and infection via post-translational modification processes. This review summarizes the important roles of the USPs in the onset and progression of inflammatory diseases, including periodontitis, pneumonia, atherosclerosis, inflammatory bowel disease, sepsis, hepatitis, diabetes, and obesity. Moreover, we highlight a comprehensive overview of the pathogenesis of USPs in these inflammatory diseases as well as post-translational modifications in the inflammatory responses and pave the way for future prospect of targeted therapies in these inflammatory diseases.

The Genetic Aspects of Periodontitis Pathogenesis and the Regenerative Properties of Stem Cells

Periodontitis (PD) is a prevalent and chronic inflammatory disease with a complex pathogenesis, and it is associated with the presence of specific pathogens, such as Porphyromonas gingivalis. Dysbiosis and dysregulated immune responses ultimately lead to chronic inflammation as well as tooth and alveolar bone loss. Multiple studies have demonstrated that genetic polymorphisms may increase the susceptibility to PD. Furthermore, gene expression is modulated by various epigenetic mechanisms, such as DNA methylation, histone modifications, or the activity of non-coding RNA. These processes can also be induced by PD-associated pathogens. In this review, we try to summarize the genetic processes that are implicated in the pathogenesis of PD. Furthermore, we discuss the use of these mechanisms in diagnosis and therapeutic purposes. Importantly, novel treatment methods that could promote tissue regeneration are greatly needed in PD. In this paper, we also demonstrate current evidence on the potential use of stem cells and extracellular vesicles to stimulate tissue regeneration and suppress inflammation. The understanding of the molecular mechanisms involved in the pathogenesis of PD, as well as the impact of PD-associated bacteria and stem cells in these processes, may enhance future research and ultimately improve long-term treatment outcomes.

Association between polymorphisms of anti-inflammatory gene alleles and periodontitis risk in a Chinese Han population

OBJECTIVE

Cytokines that mediate the immune responses are important in the pathogenesis of periodontitis. The genetic polymorphisms of IL-10, TNFAIP3 (A20), and NF-κB1 (p105/p50) and their association with the risk of periodontitis were investigated.

METHOD

Venous blood from 102 clinical periodontal healthy participants and 100 patients with periodontitis was collected to genotype the IL-10 (rs1800872), A20 (rs2230926, rs5029937, rs6927127), and NF-κB1 (rs28362491) SNP loci by Sanger technology. Univariable and multivariable logic regression and path analysis model was used to analyze the genotypes and alleles.

RESULT

Single-gene mutations in the A20 (rs2230926, rs5029937, rs6927127) and IL-10 (rs1800872) genes were not associated with the risk of periodontitis. NF-κΒ1 (rs28362491) gene influenced periodontitis susceptibility by affecting CAL. The combined effect of A20 and IL-10 was related to the risk of periodontitis (ORa = 0.123-0.151). One site mutated in the A20 (rs2230926, rs5029937, rs6927127) gene or IL-10 (rs1800872) gene reduced the risk of periodontitis.

CONCLUSION

Single gene polymorphisms in A20 and IL-10 genes were not associated with the risk of periodontitis. NF-κB1 gene polymorphism indirectly affects susceptibility to periodontitis. The combined effect of anti-inflammatory gene polymorphisms (A20 and IL-10) correlated with the decreased risk of periodontitis.

CLINICAL RELEVANCE

This study helps to explore the potential mechanisms underlying the role of anti-inflammatory genes in the progression of periodontal disease and provides a basis for the selection and development of appropriate periodontal treatment strategies based on the genetic profile of the patient.

Genetic Association of the C-C Motif Chemokine Ligand 2 (CCL2) rs1024611 Polymorphism With Periodontitis

Introduction To a large extent, a person's susceptibility to developing periodontitis is determined by their genetic makeup. Research has shown that chemokines generated during an immune response can harm the periodontal ligaments, gingiva, and alveolar bone. Various chemokine genes located on different chromosomes contribute to periodontitis, and one such gene is C-C motif chemokine ligand 2 (CCL2), associated with the rs1024611 polymorphism, which is part of a cytokine gene cluster on the q-arm of chromosome 17. Objective Our specific objective was to investigate whether CCL2 polymorphisms could influence the relative risk of developing periodontitis. Building on these findings, we aimed to compare the frequency of a specific single nucleotide polymorphism (SNP) in the CCL2 gene between individuals with and without periodontitis. Materials and methods Fifty participants were enrolled in the study after obtaining informed consent and ethical clearance. Clinical assessments, including probing pocket depth, clinical attachment loss, and bleeding on probing, were utilized to classify individuals into two groups: a control group (Group A, n=25) and a periodontitis group (Group B, n=25). DNA extraction from collected samples involved drawing 2 ml of venous blood from the antecubital fossa and transferring it into a sterile tube with a pinch of ethylene diamine tetraacetic acid (EDTA) to prevent clotting. DNA extraction was performed and polymorphisms of CCL2 were assessed through polymerase chain reaction (PCR) and restriction enzyme digestion. Results The periodontitis group consisted of 25 patients, with an average age of 39.0±0.22 years, who met the American Academy of Periodontology's 2018 criteria for at least stage II periodontitis. The control group comprised 25 individuals with an average age of 41.3±0.49 years. Regarding the CCL2 gene polymorphism (rs1024611), there was no substantial variation in genotype frequencies between the patients and controls (p = 0.695). An agarose gel electrophoretogram, along with a standard DNA ladder, demonstrated partial amplification of the CCL2 gene spanning the polymorphism site (rs1024611). Genotypes observed were as follows: homozygous AA - 333 bp; heterozygous AG - 333 + 250 + 73 bp; homozygous GG - 250 + 73 bp. Conclusion In conclusion, there is no significant association between the CCL2 gene polymorphism rs1024611 and susceptibility to periodontitis.

The Potential Role of Epigenetic Modifications on Different Facets in the Periodontal Pathogenesis

Periodontitis is a chronic inflammatory disease that affects the supporting structures of teeth. In the literature, the association between the pathogenicity of bacteria and environmental factors in this regard have been extensively examined. In the present study, we will shed light on the potential role that epigenetic change can play on different facets of its process, more particularly the modifications concerning the genes involved in inflammation, defense, and immune systems. Since the 1960s, the role of genetic variants in the onset and severity of periodontal disease has been widely demonstrated. These make some people more susceptible to developing it than others. It has been documented that the wide variation in its frequency for various racial and ethnic populations is due primarily to the complex interplay among genetic factors with those affecting the environment and the demography. In molecular biology, epigenetic modifications are defined as any change in the promoter for the CpG islands, in the structure of the histone protein, as well as post-translational regulation by microRNAs (miRNAs), being known to contribute to the alteration in gene expression for complex multifactorial diseases such as periodontitis. The key role of epigenetic modification is to understand the mechanism involved in the gene-environment interaction, and the development of periodontitis is now the subject of more and more studies that attempt to identify which factors are stimulating it, but also affect the reduced response to therapy.

The Bidirectional Relationship between Periodontal Disease and Diabetes Mellitus-A Review

Periodontitis is a chronic inflammatory disease caused by the presence of a bacterial biofilm known as dental plaque. This biofilm affects the supporting apparatus of the teeth, especially the periodontal ligaments and the bone surrounding the teeth. Periodontal disease and diabetes seem to be interrelated and in a bidirectional relationship, and have been increasingly studied in recent decades. For example, diabetes mellitus has a detrimental effect on periodontal disease, increasing its prevalence, extent, and severity. In turn, periodontitis negatively affects glycemic control and the course of diabetes. This review aims to present the most recently discovered factors that contribute to the pathogenesis, therapy, and prophylaxis of these two diseases. Specifically, the article focuses on microvascular complications, oral microbiota, pro- and anti-inflammatory factors in diabetes, and periodontal disease. As presented in this review, these two diseases require specific/ complementary therapeutic solutions when they occur in association, with new clinical trials and epidemiological research being necessary for better control of this interdependent pathogenic topic.

Sex-based Dysregulation of Inflammation-related Genes in Periodontitis

Periodontitis is a chronic inflammatory condition affecting a large population all over the world. This condition is linked with abnormal expression of numerous genes. We measured levels of CYFIP1, KDR, RABGGTA, RABGGTB and FOXD2 in gingival tissue and circulation of people with periodontitis and healthy controls. KDR was more expressed in tissue samples of female patients compared with female controls (Ratio of mean expression (RME) =4.16, P=0.02). However, this gene was less expressed in the blood of female patients compared with female control subjects (RME=0.12, P=0.04). RABGGTB was less expressed in the blood of male patients compared with male controls (RME=0.20, P=0.02). Finally, FOXD2 was less expressed in total blood samples compared with total controls (RME=0.3, P<0.001) and in blood samples of female patients compared with female control subjects (RME=0.02, P<0.001). RABGGTA had the best area under curve (AUC) value in differentiation of patients' tissues from normal tissues (AUC=0.60, sensitivity=0.37, specificity=0.92). In distinction of abnormal blood samples from controls, FOXD2 had the best performance (AUC=0.85, sensitivity=0.66, specificity=0.91). In brief, we demonstrated a sex-dependent dysregulation of KDR, RABGGTB and FOXD2 genes in circulation or tissue of patients with periodontitis.

Genome- and Transcriptome-Wide Association Studies Identify Susceptibility Genes and Pathways for Periodontitis

Several genes associated with periodontitis have been identified through genome-wide association studies (GWAS); however, known genes only explain a minority of the estimated heritability. We aimed to explore more susceptibility genes and the underlying mechanisms of periodontitis. Firstly, a genome-wide meta-analysis of 38,532 patients and 316,185 healthy controls was performed. Then, cross- and single-tissue transcriptome-wide association studies (TWAS) were conducted based on GWAS summary statistics and the Genotype-Tissue Expression (GTEx) project. Risk genes were evaluated to determine if they were differentially expressed in periodontitis sites compared with unaffected sites using public datasets. Finally, gene co-expression network analysis was conducted to identify the functional biology of the susceptible genes. A total of eight single nucleotide polymorphisms (SNPs) within the introns of lncRNA LINC02141 approached genome-wide significance after meta-analysis. EZH1 was identified as a novel susceptibility gene for periodontitis by TWAS and was significantly upregulated in periodontitis-affected gingival tissues. EZH1 co-expression genes were greatly enriched in the cell-substrate junction, focal adhesion and other important pathways. Our findings may offer a fundamental clue for comprehending the genetic mechanisms of periodontitis.

Berry as an adjunct to nonsurgical periodontal therapy: A clinical trial

Periodontal disease, a persistent inflammatory condition affecting the tissues around the teeth, is brought on by an imbalance between dental biofilm and the host's reaction, with the potential for tooth loss. Periodontal disease has been linked to an excess of free radicals induced by oxidative stress or antioxidant deficiency. There is a notable oxidative process early in the course of periodontal disease, especially in periodontitis. The objective of the study is to assess if berry supplements can be used as a supplement to nonsurgical periodontal therapy. Forty individuals with chronic periodontitis in total were divided into two groups for this study. Group A received scaling and root planing (SRP), whereas Group B received SRP plus berry supplements. At baseline and on the 28^th day, both groups had their probing pocket depth (PPD) and clinical attachment level (CAL) assessed. After then, the data from both time periods were compared. The SPSS software was used to examine the data (Version 23.0). Using an unpaired t-test, the mean PPD and CAL values were compared between the groups. The mean PPD in Group A decreased on day 28 from 4.18 ± 0.12 to 3.06 ± 0.02 while in Group B reduced from 4.21 ± 0.13 to 2.05 ± 0.08. The CAL in Group A improved from 5.05 ± 0.09 to 3.04 ± 0.11 and in Group B from 4.52 ± 0.17 to 2.02 ± 0.08. There was evidence of a statistically significant difference between two groups in terms of mean pocket depth and clinical attachment degree (P < 0.05). Therefore, berries may be an effective treatment for chronic periodontitis when used in conjunction with SRP.

The Treatment Efficiency and Microbiota Analysis of Sapindus mukorossi Seed Oil on the Ligature-Induced Periodontitis Rat Model

Periodontitis is a common oral disease mainly caused by bacterial infection and inflammation of the gingiva. In the prevention or treatment of periodontitis, anti-bacterial agents are used to inhibit pathogen growth, despite increasing levels of bacterial resistance. Sapindus mukorossi Gaertn (SM) seed oil has proven anti-bacterial and anti-inflammation properties. However, the possibility of using this plant to prevent or treat periodontitis has not been reported previously. The aim of this study was to evaluate the effects of SM oil on experimental periodontitis in rats by using micro-CT and microbiota analysis. The distance between cementoenamel junction (CEJ) and alveolar bone crest (ABC) on the sagittal micro-CT slide showed that total bone loss (TBL) was significantly lower in CEJ-ABC distances between SM oil and SM oil-free groups on Day 14. Histology data also showed less alveolar bone resorption, a result consistent result with micro-CT imaging. The microbiota analyzed at phylum and class levels were compared between the SM oil and SM oil-free groups on Day 7 and Day 14. At the phylum level, Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria were the dominant bacterium. Firmicutes in box plot analysis was significantly less in the SM oil group than in the SM oil-free group on Day 7. At the class level, Bacteroidia, Gammaproteobacteria, Bacilli, Clostridia, and Erysipelotrichia were the dominant bacteria. The bacteria composition proportion of Bacilli, Clostridiay, and Erysipelotrichia could be seen in the SM oil group significantly less than in t SM oil-free group on Day 7. Overall, the present results show that topical application of SM oil can reduce bone resorption and change bacteria composition in the ligature-induced periodontitis model. According to these results, it is reasonable to suggest SM oil as a potential material for preventing oral disease.

Association between Vitamin D Receptor Gene Polymorphisms and Periodontal Bacteria: A Clinical Pilot Study

Background: Periodontitis is an inflammatory disease caused by microorganisms involving the supporting tissues of the teeth. Gene variants may influence both the composition of the biofilm in the oral cavity and the host response. The objective of the study was to investigate the potential correlations between the disease susceptibility, the presence and the quantity of periodontopathogenic oral bacterial composition and the VDR gene polymorphisms. Methods: Fifty (50) unrelated periodontal patients and forty-one (41) healthy controls were selected for genomic DNA extraction. DNA concentration was measured and analyzed. The periodontopathogenic bacterial species were identified and quantified using a Real Time PCR performed with species-specific primers and probes. Results: Genotype distribution showed a different distribution between the groups for BsmI rs1544410 genotypes (p = 0.0001) with a prevalence of the G(b) allele in periodontal patients (p = 0.0003). Statistical significance was also found for VDR TaqI rs731236 (p ≤ 0.00001) with a prevalence of the T(T) allele in periodontal patients (p ≤ 0.00001). The average bacterial copy count for the periodontitis group was significantly higher than that of control group. Dividing patients into two groups based on high or low bacterial load, FokI rs2228570 T allele (f) was statistically more represented in patients with high bacterial load. Conclusions: The findings of the study suggest the involvement of the VDR gene BsmI and TaqI polymorphisms in periodontal disease, while FokI and BsmI may be involved in determining an increased presence of periodontopathogens.