Matrix metalloproteinase gene polymorphisms and periodontitis susceptibility: a meta-analysis involving 6,162 individuals

Patients with periodontitis might increase the risk of urologic cancers: a bidirectional two-sample Mendelian randomization study

BACKGROUND

Numerous observational epidemiological studies have reported a bidirectional relationship between periodontitis and urological cancers. However, the causal link between these two phenotypes remains uncertain. This study aimed to examine the bidirectional causal association between periodontitis and four types of urological tumors, specifically kidney cancer (KC), prostate cancer (PC), bladder cancer (BC), and testis cancer (TC).

METHODS

Based on large-scale genome-wide association study (GWAS) data, we utilized the two-sample Mendelian randomization (MR) approach to evaluate causal relationships between periodontitis and urological cancers. Several MR methods covering various consistency assumptions were applied in this study, including contamination mixture and Robust Adjusted Profile Score to obtain robust results. Summary-level data of individuals with European ancestry were extracted from the UK Biobank, the Kaiser GERA cohorts, and the FinnGen consortium.

RESULTS

Our findings revealed significant positive genetic correlations between periodontitis and kidney cancer (OR 1.287; 95% CI 1.04, 1.594; P = 0.020). We did not find a significant association of periodontitis on prostate cancer, bladder cancer, and testis cancer. In reverse MR, no significant results were observed supporting the effect of urologic cancers on periodontitis (all P > 0.05).

CONCLUSION

Our study provides the evidence of a potential causal relationship between periodontitis and kidney cancer. However, large-scale studies are warranted to confirm and elucidate the underlying mechanisms of this association.

The association between genetic polymorphisms of matrix metalloproteinases and knee osteoarthritis: A systematic review and meta-analysis

AIM

To investigate the linkage of matrix metalloproteinase (MMP) gene polymorphisms with the pathogenesis of knee osteoarthritis (OA).

METHODS

This meta-analysis study systematically retrieved relevant studies from PubMed, Embase, the Cochrane Central, Wanfang Data, CNKI, and SinoMed up to November 2020. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the association between MMP gene polymorphisms and OA.

RESULTS

A total of nine case-control studies comprising 1719 knee OA patients and 1904 controls were included in this meta-analysis. The results revealed that MMP-1-1607 (rs1799750) 1G/2G polymorphism was not significantly associated with knee OA risk in four genetic models (OR (95% CI): allele model: 0.89 (0.57, 1.40), p = .615); dominant mode: 0.82 (0.47, 1.44), p = .486; recessive model: 0.88 (0.49, 1.57), p = .659; homozygote model: 0.79 (0.34, 1.82), p = .576. The association was significant for dominant model of MMP-3 C/T: 1.54 (1.10-2.15), p = .013, especially in Asian ethnicity (1.63 (1.11, 2.39), p = .013). Variants of MMP-13 C/T polymorphism were associated with increased risk of knee OA development based on dominant model: 1.56 (1.19, 2.06), p = .001 and homozygote model: 2.12 (1.44, 3.13), p < .001, and there were significant associations between MMP-13 C/T polymorphism and knee OA risk in Asian ethnicity under different genetic models (all p > .05).

CONCLUSIONS

Present evidence suggested that the gene polymorphisms of MMP-1-1607 1G/2G may not be associated with the risk of OA. But, the dominant model of MMP-3 and MMP-13 polymorphisms in Asian ethnicity was significantly correlated with knee OA.

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.

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.

Periodontitis-resistant and -susceptible matriline regulation of gingival transcriptome in nonhuman primates

OBJECTIVE

This report identified if gingival gene expression transcriptomes demonstrated unique profiles that discriminated periodontitis-susceptible (PDS) and periodontitis-resistant (PDR) animals in health and disease.

BACKGROUND

Nonhuman primates generally organize their social groups based upon matriline origin. We have used a multi-generational colony of rhesus macaques to identify matrilines presenting with significant differences in periodontitis (e.g., earlier age onset, greater prevalence, and severity).

METHODS

Animals from 12 to 23 years of age (n = 17; 8 - PDR, 9 - PDS) were entered into a ligature-induced periodontitis trial. Gingival biopsies were taken at baseline and 0.5, 1, 3, and 5 months post-ligation, and microarray analysis was used to quantify gene expression in samples at each time point.

RESULTS

Over 1000 genes showed significant (p < .01) differences in the PDR versus PDS animals at baseline. The frequency of differences generally decreased during the disease process, and increased with resolution (i.e., 5 months). A nearly 2:1 ratio of elevated gene levels was noted in baseline PDR samples that included up-regulated MMPs, Fc receptors, chemokines, interleukins, and innate immune receptors, and down-regulated genes particularly related to epithelial biology. Most dramatically, there was a skewed differential expression of adaptive immune response genes in the PDR and epithelial cell structure/function genes in PDS samples.

CONCLUSIONS

The results demonstrate substantive differences in gingival tissue response capacity/programming in PDR and PDS samples that may contribute to the differences in clinical outcomes related to the heritability of disease risk through matrilines.

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.

Matrix Metalloproteinases in Oral Health-Special Attention on MMP-8

Matrix metalloproteinases (MMPs) are a large family of Ca²⁺ and Zn²⁺ dependent proteolytic enzymes, able to cleave the various components of the extracellular matrix (ECM), as well as a range of other regulatory molecules. Several reports have proven the important role of both MMPs and their endogenous inhibitors, TIPMs, in oral health, the initial development of the tooth, and during enamel maturation. In this mini-review, we aim to summarize the literature information about the functions of MMPs, paying more attention to MMP-8 (collagenase-2 or neutrophil collagenase) in the development and progression of periodontitis, peri-implantitis, and carious lesions. We also emphasize the role of particular gene variants in MMP8 as predisposing factors for some oral diseases.

Periodontal Disease Pathogens, Pathogenesis, and Therapeutics: The CRISPR-Cas Effect

Periodontal disease (PD) is an immune-inflammatory disease affecting the supporting structures of the teeth, which results in progressive destruction of the hard and soft tissues surrounding teeth, ultimately resulting in tooth loss. The primary etiological factor for this disease is the presence of pathogenic microorganisms. Pathogenic bacteria face antagonistic conditions and foreign DNA components during the infection stage and depend on defense mechanisms such as clustered regularly interspaced short palindromic repeats (CRISPR)-Cas to counter them. Virulence genes regulated by the CRISPR-Cas system are often expressed by bacteria as part of the stress response to the presence of stress conditions and foreign elements. There is ever-growing evidence regarding the role of CRISPR-Cas in virulence of periodontal pathogens. The same CRISPR-Cas system may also be targeted to reduce bacterial virulence and it may also be utilized to develop diagnostic and therapeutic strategies for prevention and control of PD progression. This review article describes the CRISPR-Cas systems in the periodontal dysbiotic microbial communities, their role in the virulence of periodontal pathogens, and their potential role in understanding the pathogenesis of periodontitis and treatment of PD.

Matrix Metalloproteinase-3 but Not Matrix Metalloproteinase-9, Implicated in the Manifestation of Chronic Periodontitis

Background

Periodontal disease is an inflammatory condition affecting the tooth's supporting tissues, resulting in gradual loss of periodontal ligament (PDL), alveolar bone, and gum resorption. Neutrophil and monocyte/macrophage, destructive proteases like matrix metalloproteinase (MMP)-3 and MMP-9 play pivotal roles in such lesions in periodontitis. Therefore, this study aims to compare the level of MMP-3 and MMP-9 gene expression in patients with or without periodontitis in an Iranian population.

Methods

This cross-sectional study was carried out on 22 chronic periodontitis patients and 17 healthy control subjects referred to the department of periodontology, Mashhad Dental School. In both groups, the gingival tissue was removed during surgery and transferred to the Molecular Biology Laboratory for MMP-3 and MMP-9 gene expression evaluation. The qRT-PCR, TaqMan method was used for gene expression assessments.

Results

The average age of periodontitis patients was 33± 5 years, and in controls, 34.7± 6 with no significant differences. The mean MMP-3 expression in periodontitis patients was 146.67±38.7, and in controls, 63.4±9.1. The difference was statistically significant (P=0.04). The mean expression of MMP-9 in periodontitis patients and controls were 103.8± 21.66 and 87.57± 16.05, respectively. Although the target gene expression in patients was higher, the difference was insignificant. Furthermore, there was not any significant correlation between age or gender with the expression of MMP3 or MMP9.

Conclusion

The study demonstrated that the MMP3 seems to have a destructive impact on the gingival tissue in chronic periodontitis, but not MMP9.

Matrix metalloproteinase-9-1562 C/T promoter gene polymorphism in chronic periodontitis: A cross-sectional observational study

Background:

Matrix metalloproteinases (MMPs) are a major group of enzymes, released in inflamed periodontal tissues in large quantities, resulting in connective tissue matrix breakdown. One of the most predominant MMPs is MMP-9. Association between chronic periodontitis (CP) and MMP-9 gene polymorphism (GP) in some ethnic populations has been already established. The aim of the current study was to assess the association of single-nucleotide polymorphism in the promoter region of MMP-9 gene with CP in Kolkata population, if any.

Materials and Methods:

Forty eligible individuals were recruited for the study and grouped as A and B: Group A (twenty periodontally healthy individuals) and Group B (twenty CP patients). Venous blood samples collected from all the forty individuals were used to isolate the genomic DNA. GP for MMP-9 gene was detected using polymerase chain reaction and sequencing method. The data obtained were then analyzed statistically.

Results:

A significantly different genotypic and allelic variation was observed in the control and test groups, with C/T genotype and T allele present in only CP group.

Conclusion:

Within the limitations of this study, we can conclude that there was no significant association between patients with periodontitis and MMP-9-1562 C/T promoter GP.

Changes in salivary matrix metalloproteinase-3, -8, and -9 concentrations after 6 weeks of non-surgical periodontal therapy

Background

Studies using salivary inflammatory biomarkers for diagnosing and monitoring the progression of periodontal disease have garnered increased attention in recent years. The present study aimed to identify changes in clinical parameters and concentrations of salivary matrix metalloproteinases (MMPs) following 6 weeks of non-surgical periodontal therapy (NSPT).

Methods

A 6-week NSPT program was applied to 51 adults aged ≥ 20 years. The program involved scaling, root planing, and professional toothbrushing for healthy participants and those with periodontal disease. Patients with periodontal disease underwent professional toothbrushing during all three visits. Periodontal pocket depth (PD) and gingival bleeding were assessed at week 0, week 3, and week 6, and saliva samples were collected to measure the concentrations of MMP-3, -8, and -9.

Results

All clinical parameters were improved in the periodontal disease groups following the NSPT course. Compared with healthy participants, the patients with periodontal disease showed increased concentrations of salivary MMP-3, -8, and -9. During the 6-week program, patients with periodontal disease also showed significant reductions in PD and gingival bleeding during the third week; no significant reduction was found during the sixth week. Significant reductions in the concentrations of salivary MMP-3, -8, and -9 were also noted in the periodontal disease group at week 3. The sensitivity and specificity of MMP-3 for predicting periodontitis were 81.8% and 55.5%, respectively.

Conclusion

The present study found that NSPT resulted in reductions of salivary MMP-3, -8, and -9, and identified the potential of MMP-3 as a biomarker in the diagnosis of periodontal disease. These findings may serve as foundational data for future studies into the development of diagnostic kits for periodontal disease.

The Role of Matrix Metalloproteinases (MMP-8, MMP-9, MMP-13) in Periodontal and Peri-Implant Pathological Processes

Severe periodontitis, a destructive inflammatory disease of the supporting tissues of the teeth, ranks sixth in terms of global spread, affecting about 11% of the population. Metalloproteinases (MMPs) are extracellular matrix (ECM) macromolecules that are important in cellular development and morphogenesis, and they are capable of activating growth factors in their proximity, cell surface receptors, and adhesion molecules. MMPs are part of a major family of zinc-dependent endopeptidases, and their activity is modulated and regulated by certain inhibitors known as tissue metalloproteinase inhibitors (TIMPs). Because type I collagen is the major component of the periodontal extracellular matrix, special attention has been paid to the role of collagenases, especially MMP-8 and MMP-13 and gelatinases, MMP-2 and MMP-9, in periodontal diseases. In fact, MMP-8 (or collagenase 2) is currently one of the most promising biomarkers for periodontitis in oral fluids. Among them, salivary MMP-9 has been shown to be a more sensitive marker for periodontal inflammation during orthodontic treatment, which opens new perspectives in reducing periodontal hazards during such treatments. Both MMP-8 and MMP-9 are extremely valuable diagnostic tools in treating periodontitis, and future studies and healthcare policies should focus on implementing more accessible methods of chairside testing in order to reduce the prevalence of this disease.

Evaluation of Gene Polymorphism and Gingival Crevicular Fluid Levels of Matrix Metalloproteinase-3 in a Group of Turkish Periodontitis Patients

INTRODUCTION

Periodontitis is characterized by the destruction of tooth-supporting tissues. Matrix metalloproteinases (MMPs) play a significant part in the degradation of collagen structure. The gingival crevicular fluid (GCF) levels of MMPs increase with the progression of periodontal inflammation. Polymorphisms can be responsible for high expression of MMPs and can exacerbate the breakdown of collagen structure. This study aims to investigate the effect of MMP-3 -1171 5A/6A polymorphism and the GCF levels of MMP-3 in a group of Turkish periodontitis patients.

MATERIALS AND METHODS

Non-smoking, stage II grade A periodontitis (S II-Gr A) (n = 68) and stage II grade B periodontitis (S II-Gr C) (n = 64) patients were recruited. Healthy individuals (H) (n = 72) without signs of gingivitis or periodontitis served as the control. Venous blood was collected from participants to obtain DNA, and the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to detect polymorphism. GCF samples were taken to assess MMP-3 levels using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

The MMP-3 -1179 5A/6A distribution showed no significant difference between the groups (p > 0.05). However, the MMP-3 GCF levels of the S II-Gr C group were higher than those of both the S II-Gr A and H groups (p < 0.05), and elevated MMP-3 levels were detected in S II-Gr A compared to H (p < 0.05).

CONCLUSION

The MMP-3 GCF levels showed an association with periodontal tissue destruction, although single nucleotide polymorphism was not associated with the S II-Gr C and S II-Gr A groups in the Turkish population.

Effect of Aging on Homeostasis in the Soft Tissue of the Periodontium: A Narrative Review

Aging is characterized by a progressive decline or loss of physiological functions, leading to increased susceptibility to disease or death. Several aging hallmarks, including genomic instability, cellular senescence, and mitochondrial dysfunction, have been suggested, which often lead to the numerous aging disorders. The periodontium, a complex structure surrounding and supporting the teeth, is composed of the gingiva, periodontal ligament, cementum, and alveolar bone. Supportive and protective roles of the periodontium are very critical to sustain life, but the periodontium undergoes morphological and physiological changes with age. In this review, we summarize the current knowledge of molecular and cellular physiological changes in the periodontium, by focusing on soft tissues including gingiva and periodontal ligament.

Periodontal health and disease: The contribution of genetics

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

Association of MMP-2-753C>T and MMP-9-1562C>T Polymorphisms with Chronic/Aggressive Periodontitis Risk: A Systematic Review and Meta-Analysis

BACKGROUND

Two functional polymorphisms in the matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9) genes may contribute to periodontitis pathogenesis. However, the results were inconsistent and inconclusive. Therefore, to clarify precise associations of MMP-2-753 C>T and MMP-9-1562C>T polymorphisms with chronic (CP) and aggressive (AgP) periodontitis, we performed a systematic review and meta-analysis.

METHODS

A literature search was conducted using PubMed, Google Scholar, Embase, and Web of Science databases until 5 July 2017. The data were analyzed with CMA software, and risk estimates are expressed as odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Nineteen case-control studies in ten publications with 2089 periodontitis cases and 2345 controls met the criteria. The pooled ORs indicated that MMP-2-753C>T and MMP-9-1562C>T polymorphisms were not significantly associated with risk of periodontitis in overall analysis. Stratified analyses by ethnicity and periodontitis type indicated that the MMP-9-1562C>T polymorphism showed a significant association with the risk of periodontitis among Caucasians and CP/AgP subgroup, whereas MMP-2-753C>T polymorphism was significantly associated with periodontitis risk only among Asians.

CONCLUSION

MMP-2-753C>T and MMP-9-1562C>T polymorphisms may not be associated with risk of periodontitis in overall population. However, MMP-2-753C>T and MMP-9-1562C>T polymorphisms might have influence on the susceptibility of periodontitis by ethnicity.

IL18 Polymorphism and Periodontitis Susceptibility, Regardless of IL12B, MMP9, and Smoking Habits

Genetic variations contribute to the susceptibility in the development of periodontitis. The aim of this study was to investigate the influence of IL18, IL12, and MMP9 polymorphisms in the chronic periodontitis. This case-control study involved 381 individuals matched by gender and age. Genotyping of IL18 (rs187238 and rs1946518) and IL12B (rs3212227) was performed by PCR-SSP and PCR-RFLP was used for MMP9 (rs3918242). IL-18 and MMP-9 were quantified in the serum by ELISA. SNPStats and OpenEpi software were used for statistical analysis and, in order to eliminate smoking as a confounding factor, the analyses were also performed in nonsmoking subjects. The IL18-137G/C genotype was associated with the risk of chronic periodontitis in nonsmokers (P_c = 0.03; OR = 1.99; overdominant inherence model). In the multivariate analyses, homozygous IL18-137G/G and IL18-607C/C were more frequent in males compared to women with these same genotypes (OR = 2.51 and OR = 3.30, respectively). The serum levels of the IL-18 in patients were higher than those in healthy controls (P = 0.005). IL12B and MMP9 polymorphisms and MMP-9 serum concentration were similar in patients and controls. In this study, IL18 was associated with chronic periodontitis susceptibility. Men had greater risk than women for developing the disease when IL18 polymorphism was considered and the susceptibility was independent of the smoking status.

DEFB1 rs11362 Polymorphism and Risk of Chronic Periodontitis: A Meta-Analysis of Unadjusted and Adjusted Data

Objective: Chronic periodontitis (CP) is a growing problem that affects the worldwide population, having significant impacts on people's daily lives and economic development. Genetics is an important component in the determination of individual susceptibility to periodontal diseases. Numerous studies have been performed to investigate the association between beta defensin 1 (DEFB1) rs11362 polymorphism and risk of CP, but the results are still inconclusive. Therefore, we conducted this meta-analysis to ascertain whether this variation in DEFB1 is associated with CP susceptibility.

Methods: The relevant studies were searched in PubMed and Chinese National Knowledge Infrastructure (CNKI) databases up to January 9, 2018. Two independent authors selected citations and extracted the data from eligible studies. Odds ratios (ORs) with their 95% confidence intervals (95% CIs) were used to assess the strength of the association.

Results: Seven case-control studies were included in this meta-analysis. Based on unadjusted data, there was no obvious association between DEFB1 rs11362 polymorphism and CP risk in all genetic models (A vs. G: OR = 0.86, 95%CI = 0.61–1.20; AA vs. GG: OR = 0.83, 95% CI = 00.50–1.39; AG vs. GG: OR = 1.01, 95%CI = 0.73–1.39; AG+AA vs. GG: OR = 0.91, 95% CI = 00.74–1.11; and AA vs. AG+GG: OR = 0.83, 95% CI = 00.57–1.21); the results of adjusted data also showed no significant relationship. Subgroup analyses based on ethnicity, participants' smoking status, HWE in controls and severity of CP all revealed similar results to that of the overall analysis. Sensitivity analysis indicated the results were robust and no evidence of publication bias was found.

Conclusions: Our meta-analysis suggests that DEFB1 rs11362 polymorphism may not have an important effect on the risk of CP. Further large-scale and well-designed studies are necessary to validate our conclusion in the future.

Gene coexpression analysis reveals dose-dependent and type-specific networks responding to ionizing radiation in the aquatic model plant Lemna minor using public data

Ionizing radiations (IRs) are widespread damaging stresses to plant growth and development. However, the regulatory networks underlying the mechanisms of responses to IRs remains poorly understood. Here, a set of publicly available transcriptomic data (conducted by Van Hoeck et al. 2015a), in which Lemna minor plants were exposed to a series of doses of gamma, beta and uranium treatments was used to perform gene coexpression network analysis. Overall, the genes involved in DNA synthesis and chromatin structure, light signalling, photosynthesis, and carbohydrate metabolism were commonly responsive to gamma, beta and uranium treatments. Genes related to anthocyanin accumulation and trichome differentiation were specifically downregulated, andgenes related to nitrogen and phosphate nutrition, cell vesicle transport, mitochondrial electron transport and ATP synthesis were specifically upregulated in response to uranium treatment. While genes involved in DNA damage and repair, RNA processing and RNA binding were specifically downregulated and genes involved in calcium signalling, redox and degradation of carbohydrate metabolism were specifically upregulated responding to gamma radiation. These findings revealed both dose-dependent and typespecific networks responding to different IRs in L. minor, and can be served as a useful resource to better understand the mechanisms of responses to different IRs in other plants.

Evaluation of collagenase-3 matrix metalloproteinase-13 gene-associated polymorphisms 11A/12A and -77A/G and its associated alleles with and without periodontitis

Context:

Connective tissue devastation in periodontitis and other chronic inflammatory diseases is a major concern. There are several inflammatory mediators associated with this process among which matrix metalloproteinases (MMPs) play a predominant role. Collagen degradation is primarily mediated by the collagenases. MMP-13 is familiar as collagenase-3, which has the aptitude to humiliate fibrillar collagen.

Aims:

This study aims to evaluate MMP-13 promoter polymorphism, 11A/12A, and −77A/G and associated alleles in patients with and without chronic periodontitis (CP).

Settings and Design:

This was an observational case–control study.

Materials and Methods:

Of the total 100 patients, 50 with CP (test group) and 50 without CP (Control group), blood was collected for deoxyribonucleic acid isolation. The 11A/12A and −77A/G polymorphisms of the MMP-13 gene were picked out by polymerase chain reaction (PCR)- single-strand conformation polymorphism analysis method and PCR-restriction fragment length polymorphism by BseNI restriction enzyme, respectively.

Statistical Analysis Used:

Association between MMP-13 genotype (GTs) (11A/12A, 11A/11A, 12A/12A) and (AA, AG, GG) was assessed by Chi-square and Student's t-test for intergroup comparison.

Results:

11A/12A GT was seen in 24% and 20%, 11A/11A 64% and 72%, 12A/12A 12% and 8% in test and control groups, respectively. However, the association was not statistically significant. −77A/G polymorphism associated GT s AA was 56% and 62%, AG 24% and 28%, GG 20% and 10% in test and controls, respectively. An association of GG was statistically significant.

Conclusion:

The present study results indicated that MMP-13 −77A/G gene polymorphisms, GG GT may be predicted intensive ability for CP. On the other hand, there was no significant association between MMP-13 11A/12A gene polymorphisms with CP.

Interleukin-1β rs1143627 polymorphism with susceptibility to periodontal disease

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

IL-13 -1112 polymorphism and periodontitis susceptibility: a meta-analysis

Background

Several studies have examined the association between the IL-13 -1112C/T polymorphism and the risk of periodontitis. However, these studies have reached different conclusions. The aim of the current study was to investigate the link between this IL-13 -1112 polymorphism and susceptibility to periodontitis.

Methods

We utilized electronic databases, including the CNKI (China National Knowledge Infrastructure), Wanfang, PubMed, Embase, and Cochrane Library databases, to manually search for relevant research published through November 30, 2016. The Chinese and English terms used to search the literature included “periodontitis”, “periodontal disease”, “IL 13”, “IL-13”, and “interleukin-13”. In accordance with our inclusion criteria, we selected studies that involved case-control trials. All of these case-control trials described their objectives, design and specific statistical methods. For all included studies, odds ratios (ORs) and 95% confidence intervals (95% CIs) were provided or could be calculated from the study data. The quality of the included literature was evaluated using the Newcastle-Ottawa scale (NOS). STATA 12.0 was used to calculate the sizes of the combined effects and conduct a sensitivity analysis of the results.

Results

Our meta-analysis included 4 articles representing 5 case-control studies with a total of 710 cases and 671 control subjects. The meta-analysis results indicated that the CC vs TT model, CT vs TT model and TT vs CT + CC model (CC VS TT: OR = 0.615, 95% CI = 0.395–0.957; CT vs TT: OR = 0.518, 95% CI = 0.323–0.830; and TT vs CT + CC: OR = 1.739, 95% CI = 1.130–2.676) were significant in five IL-13 -1112 gene polymorphism and periodontitis susceptibility models. Subgroup analysis indicated that the CC vs TT, CT vs TT and TT vs CT + CC models were significant in the chronic periodontitis (CP) group, whereas no significant differences were found in the five aggressive periodontitis (AgP) group models. The sensitivity analysis showed that dropping any single study did not affect the pooled analysis results.

Conclusion

The IL-13 -1112 polymorphism may be associated with susceptibility to periodontitis. The IL-13 -1112 gene polymorphism may be associated with susceptibility to CP but not to AgP. Thus, large-scale, multi-ethnic case-control trials are still warranted.

Genetic Association between Matrix Metalloproteinases Gene Polymorphisms and Risk of Prostate Cancer: A Meta-Analysis

Background and Objective: Studies suggests that matrix metalloproteinase (MMP)-2-1306 C/T and MMP-1-1607 1G/2G polymorphisms affect the risk of prostate cancer. However, the conclusions remain controversial and no pooled evidence of this topic has been published. Therefore, we aimed to perform a meta-analysis to shed some light on the controversial conclusion pertaining to the associations of MMP-2-1306 C/T and MMP-1-1607 1G/2G polymorphisms with prostate cancer susceptibility.

Methods: A thorough literature search was performed up to August, 2016 with the PubMed, EMBASE, CBM, CNKI, and Wanfang databases. Odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) were calculated to address the correlations between these polymorphisms and risk of prostate cancer.

Results: The meta-analysis included six studies (1,921 patients and 1,988 controls) on MMP-2-1306 C/T polymorphism and three studies on MMP-1-1607 1G/2G polymorphism (438 patients and 394 controls), respectively. The overall results of meta-analysis showed that an elevated risk of the disease was implicated in MMP-2-1306 C/T polymorphism under two genetic models (CT vs. CC: OR = 1.78, 95% CI = 1.33–2.38; TT+CT vs. CC: OR = 1.62, 95% CI = 1.24–2.12) and no significant association was observed between MMP-1-1607 1G/2G polymorphism and the risk of prostate cancer. The subgroup analysis results of MMP-2-1306 C/T polymorphism were similar to the overall results. However, decreased risk of prostate cancer was observed in the Caucasians for MMP-1-1607 1G/2G polymorphism.

Conclusions: Current meta-analysis indicates that MMP-2-1306 C/T polymorphism is associated with elevated risk of prostate cancer, but MMP-1-1607 1G/2G polymorphism may inhibit the occurrence of prostate cancer in Caucasians. Further studies are warranted to verify the conclusions.

Simvastatin modulates gingival cytokine and MMP production in a rat model of ligature-induced periodontitis

Purpose

The aim of this study was to evaluate the effect of simvastatin on the synthesis of cytokines TNF-α and IL-10 and metalloproteinase (MMPs) 2 and 9 in a rat model of ligature-induced periodontitis.

Materials and methods

Twenty Wistar rats were used, and a cotton ligature was place in a subgingival position encircling the entire cervix of the first molar of the left (ipsilateral) side of the mandible. The right (contralateral) side of the mandible had no ligature placed and was used as control. After the ligature placement, animals were randomly assigned to two experimental groups (n=10): 1) rats with ligature + vehicle (saline; 10 mL/kg; orally) and 2) rats with ligature + simvastatin (25 mg/kg; orally). After 14 days of treatment, the animals were euthanized by anesthetic overdose and the gingival tissue was removed and homogenized in appropriate buffer. MMP-2 and -9 release as well as the IL-10 and TNF-α levels were detected by enzyme-linked immunosorbent assay. Statistical comparison was performed by unpaired Student’s t-test, with p<0.05 representing significance.

Results

No differences were observed for TNF-α production between the groups (p>0.05). However, IL-10 was upregulated in simvastatin-treated animals (1.8-fold increase) in comparison with the vehicle-treated group (p<0.05). Simvastatin reduced the gingival levels of MMP-9 (64.3%) in comparison with vehicle-treated samples (p<0.05).

Conclusion

Oral treatment with simvastatin increased the release of IL-10 and reduced the MMP-9 in ligature-induced periodontitis model in rats.

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

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

Matrix Metalloproteinases as Regulators of Periodontal Inflammation

Periodontitis are infectious diseases characterized by immune-mediated destruction of periodontal supporting tissues and tooth loss. Matrix metalloproteinases (MMPs) are key proteases involved in destructive periodontal diseases. The study and interest in MMP has been fuelled by emerging evidence demonstrating the broad spectrum of molecules that can be cleaved by them and the myriad of biological processes that they can potentially regulate. The huge complexity of MMP functions within the 'protease web' is crucial for many physiologic and pathologic processes, including immunity, inflammation, bone resorption, and wound healing. Evidence points out that MMPs assemble in activation cascades and besides their classical extracellular matrix substrates, they cleave several signalling molecules-such as cytokines, chemokines, and growth factors, among others-regulating their biological functions and/or bioavailability during periodontal diseases. In this review, we provide an overview of emerging evidence of MMPs as regulators of periodontal inflammation.