Analysis of the MMP-9 (C-1562 T) and TIMP-2 (G-418C) gene promoter polymorphisms in patients with chronic periodontitis

Unveiling TIMPs: A Systematic Review of Their Role as Biomarkers in Atherosclerosis and Coronary Artery Disease

Coronary artery disease (CAD) is the leading cause of death globally and is a heart condition involving insufficient blood supply to the heart muscle due to atherosclerotic plaque formation. Atherosclerosis is a chronic disease in which plaques, made up of fat, cholesterol, calcium, and other substances, build up on the inner walls of arteries. Recently, there has been growing interest in finding reliable biomarkers to understand the pathogenesis and progression of atherosclerosis. Tissue Inhibitors of Metalloproteinases (TIMPs) have emerged as potential candidates for monitoring atherosclerotic development. TIMPs are a family of endogenous proteins that regulate matrix metalloproteinases (MMPs), enzymes involved in remodeling the extracellular matrix. A systematic search using Prisma guidelines was conducted and eleven studies were selected from four different databases: Web of Science (WOS), Scopus, Ovid, and PubMed. The Newcastle-Ottawa Scale (NOS) score was used to assess the risk of bias for each study. A meta-analysis was performed, and the hazard ratio (HR) and its 95% confidence interval (CI) were determined. Among the eleven studies, six reported a positive association between higher levels of TIMPs and an increased risk of atherosclerosis. Conversely, four studies support low TIMPs with high CAD risk and one study showed no significant association between TIMP-2 G-418C polymorphism and CAD. This divergence in findings underscores the complexity of the relationship between TIMPs, atherosclerosis, and CAD. In addition, a meta-analysis from two studies yielded a HR (95% CI) of 1.42 (1.16-1.74; p < 0.001; I2 = 0%) for TIMP-2 in predicting major adverse cardiovascular events (MACEs). In conclusion, the existing evidence supports the notion that TIMPs can serve as biomarkers for predicting the severity of atherosclerosis, myocardial damage, and future MACEs among CAD patients. However, further exploration is warranted through larger-scale human studies, coupled with in vitro and in vivo investigations.

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.

The Association of Matrix Metalloproteinase Gene Polymorphisms and Periodontitis: An Overview

Periodontitis is a multifactorial inflammatory disease, pathogenic bacteria being the primary etiological agents. The host response and the severity of clinical manifestation are determined by genetic and environmental factors. There is some evidence that the individual response to environmental variations in the immune response in periodontitis is associated with genetic factors. Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes located in the extracellular matrix. Their primary function is the breakdown of connective tissue components. Their role in the oral cavity is very vital. In this literature review, we summarized the contemporary knowledge on the function of MMPs in oral cavity and periodontal disease.

TIMP-2 Polymorphisms Define Subtypes of Hypertensive Intracerebral Hemorrhage with Distinct Perihematomal Edema Development Patterns

BACKGROUND

Perihematomal edema (PHE) is a major threat leading to poor functional outcomes after intracerebral hemorrhage (ICH). TIMP-2 is considered to participate in the formation of PHE after ICH by antagonizing the damaging effects of MMP-2. In the early study, the polymorphisms of TIMP-2 rs8179090 have shown to influence the expression of TIMP-2.

OBJECTIVE

To prove that the severity of PHE was different in ICH patients with different TIMP-2 rs8179090 genotypes.

METHODS

In this prospective study, 130 hypertensive ICH patients were enrolled. The poly phisms of rs8179090 in TIMP-2 were determined. The hematoma volume and PHE volume were measured by computed tomography (CT) scan immediately after the onset of ICH, and were measured again one week and two weeks after the onset. Then, the comparison of TIMP-2 rs8179090 genotypes was made.

RESULTS

TIMP-2-418 position (rs8179090) had two genotypes in the studied population, GC and GG. Patients with the GC genotype developed more severe PHE, with a higher incidence of delayed cerebral edema in cerebral hemorrhage than those with the GG genotype.

CONCLUSION

We have found that the GC genotype group may develop more severe PHE, with an increased incidence of delayed cerebral edema in cerebral hemorrhage.

TIMP2 Polymorphisms Association With Curve Initiation and Progression of Thoracic Idiopathic Scoliosis in the Caucasian Females

Idiopathic scoliosis (IS) etiology remains unclear, but strong genetic background is suggested. Previously reported TIMP2 study indicates an association of genic rs8179090 with IS progression in a Han Chinese population. However, there has been a lack of investigation into intragenic TIMP2 polymorphisms in IS patients. We recruited 100 Caucasian females with IS and 100 controls. Patients were subdivided accordingly to: progression rate, curve severity, joint mobility, and curve pattern. Allele-specific-polymerase chain reaction based on fluorescence resonance energy transfer was applied to evaluate nine TIMP2 polymorphisms. Distribution of genotype and allele frequency in only one polymorphism (rs11658743) differed in case-control study. Four of the polymorphisms (rs2277700, rs11077401, rs2376999, and rs4789934) showed non-equal distributions either in genotype or/and allele distributions in the patients of different progression rates. The rs11077401 was related to curve severity patients distinction and the rs8179090 distinguished patients with different joint mobility level. Two polymorphisms either differed statistically in case of curve patterns subgrouping (rs8068674 and rs8179090) or showed a slight tendency toward significance in the recessive model of allele distributions (rs9916809 and rs8179090). The remaining two polymorphisms (rs2377005, rs11658743) showed no association with either clinical or radiographic IS characteristics. The influence of the G allele of the rs8179090 on the clinical course of IS has not yet been confirmed. We identified four TIMP2 polymorphisms (rs11077401, rs2376999, rs2277700, and rs4789934) that were associated with a higher risk of the progressive IS form. Further genetic association studies based on suggested clinical criteria would be necessary to validate TIMP2 polymorphisms associated with the curve progression. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2217-2225, 2019.

Genetic Involvement in Dental Implant Failure: Association With Polymorphisms of Genes Modulating Inflammatory Responses and Bone Metabolism

Implant loss is the most serious complication of dental implants. Although the problems and causes behind the implant failure are clearly defined today, determination of the underlying causes of failure varies by the case. The clusterization phenomenon of implant loss (multiple implant failures) implies the existence of genetic risk factors. Inflammation has a critical effect on osseointegration and implant success. Peri-implantitis is an inflammatory disease of tissue supporting the tooth or implant. Inflammation leads to loss of support tissue, particularly bone, resulting in failure of implants. A single nucleotide polymorphism (SNP) of pro-inflammatory mediator genes may affect their expression levels or amino acid sequence, and, consequently, the host inflammatory response. Since the end of the past century, many studies have been conducted to investigate the association of SNP with implant failure and related conditions. Involvement of several groups of genes-including interleukins, tumor necrosis factor-α, matrix metalloproteinases, and growth factors involved in immune regulation, inflammatory response, and bone metabolism-has been explored. Some have been found to be associated with implant loss and considered potential genetic risk factors for implant failure. In this review, we summarize results of recent studies of impact of genetic factors on dental implant failure.

Analysis of MMP-7 and TIMP-2 gene polymorphisms in coronary artery disease and myocardial infarction: A Turkish case-control study

Matrix metalloproteinase (MMP) and tissue inhibitors of metalloproteinase (TIMP) have a significant role in tissue remodeling related to cardiac function. In earlier studies, MMP-7 A-181G (rs11568818), C-153T (rs11568819), C-115T (rs17886546), and TIMP-2 G-418C (rs8179090) polymorphisms have been studied in various diseases. However, association between coronary artery disease (CAD) and these polymorphisms has been poorly studied. The goal of this study is to investigate the association of CAD and myocardial infarction (MI) with MMP-7 or TIMP-2 polymorphisms. This study included 122 CAD patients and 132 control individuals. DNA was extracted from whole blood. Polymerase chain reaction-restriction fragment length polymorphism and automated direct sequencing method were used for genotyping of these polymorphisms. No significant differences were found between MMP-7 A-181G, C-115T, and TIMP-2 G-418C polymorphism and CAD or MI in a Turkish population. Despite the fact that the genotypes of MMP-7 C-153T polymorphism had no significant differences among MI and control groups, allele frequencies of C-153T polymorphism were significantly different between the two groups. Our study is the first report to clarify the appreciable relationship between MMP-7 C-153T polymorphism and MI development in CAD patients. However, these findings also need to be confirmed in other populations so we can improve our knowledge about the genetic factors affecting the development of CAD.

Multiple sclerosis: Association of gelatinase B/matrix metalloproteinase-9 with risk and clinical course the disease

BACKGROUND

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammation and axonal degeneration of the central nervous system and a leading cause of disability in young adults. The matrix metalloproteinases in general and specially gelatinase B/metalloproteinase-9 (MMP-9) plays a role in the pathogenesis of multiple sclerosis.

OBJECTIVE

To investigate the presence of the MMP-9 -1562C/T polymorphism in a Portuguese population of MS patients and assess its impact in susceptibility and course of the disease. The relation of MMP-9 serum levels with the polymorphism and with clinical and therapeutic factors will also be assessed.

METHODS

Our study included 355 Caucasian individuals distributed as MS patients (n=169) and controls (n=186). Samples were genotyped for -1562C/T polymorphism by PCR-RFLP analysis. MMP-9 concentration in serum was analyzed using a commercially available enzyme-linked immunosorbent assay.

RESULTS

A significant increase in T-allele frequency was found in female MS patients, but not in the total patient population. No association between the presence of the polymorphism and disease progression was found. MMP-9 serum concentrations were increased in patients, and although not influenced by the -1562C/T polymorphism, were modified by INF-beta therapy.

CONCLUSION

Although we did not find an association of this polymorphism with disease susceptibility or prognosis, MMP-9 appears to be a good therapeutic response marker for multiple sclerosis.

Inflammatory mediator polymorphisms associate with initial periodontitis in adolescents

Several studies have addressed cytokine gene polymorphisms and their possible associations with periodontitis. We examined the association between salivary anti- and pro-inflammatory mediator polymorphisms and initial periodontitis in Finnish adolescents, taking into account the effect of smoking. Salivary samples of 93 clinically examined adolescents from Eastern Finland were analyzed. Their oral health and smoking habits were recorded. Periodontal probing depth (PPD), and bleeding on probing (BOP) at four sites per tooth, root calculus (RC), and visible plaque index (VPI) were recorded from the index teeth. Salivary MMP-8 median values were assessed. The sites with ≥4 mm PD were categorized as follows: PPD1 = one or more ≥4 mm pocket, PPD2 = two or more ≥4 mm pockets, and PPD3 = three or more ≥4 mm pockets. Genomic DNA was extracted from 300 μl of the saliva samples by genomic QIAamp® DNA Blood Mini Kit and genotyped for polymorphisms. Genetic variants for genotyping were selected from the following genes of interest: S100A8, FCGR2A, FCGR2B, IL10, MMP8, MMP3, MMP13, VDR, TLR4, MMP2, MPO, ELANE, IL1A, IL1B, IL1RN, CD28, MMP9, DDX39B, NFKBIL1, LTA, TNF, SOD2, IL6, TLR4, TIMP1, and SYN1. After false discovery rate control (FDR), polymorphisms in MMP3 (rs679620, rs520540, rs639752), CD28 (rs3116496), and VDR (rs2228570) associated (FDR q < 0.05) with deepened periodontal pockets. Smoking did not affect the results. Genetic polymorphisms of pro-inflammatory mediators MMP3, CD28, and VDR seem to link to initial periodontitis.

A meta-analysis of MMP-9 promoter -1562 C/T polymorphism on susceptibility of chronic periodontitis

Background

Although many studies have focused on the association of the MMP-9 promoter −1562 C/T polymorphism with the susceptibility and/or severity of chronic periodontitis (CP), results have been inconsistent. Therefore, a meta-analysis of all eligible studies was performed to derive a more precise estimation of the association between this polymorphism and CP risk.

Methods

All relevant studies were identified through a database search in PubMed, Medline, and Web of Science. All the full-text studies with appropriate analytical design, published in English, which evaluated the association of MMP-9 promoter −1562C/T polymorphism with CP risk using validated genotyping methods, and with non-duplicated data were selected for this study. A fixed-effect model was used to calculate pooled ORs in the absence of heterogeneity across included trials (P > 0.1 and I² < 50 %), otherwise the random-effect model was applied.

Results

In an overall meta-analysis, pooled ORs revealed that T variant in the MMP-9 promoter −1562 C/T polymorphism was associated with a significantly decreased risk for CP under all comparison models. In subgroup analyses by ethnicity, pooled ORs showed that a significant association of the MMP-9 promoter −1562 C/T polymorphism with CP risk was only detected in Caucasians and Asians but not in mixed population. In the subgroup analysis by severity of CP, pooled ORs indicated that T allele of the MMP-9 promoter −1562 C/T polymorphism was associated with decreased susceptibility to severe CP while there was no significant association between this polymorphism and moderate CP.

Conclusions

Our meta-analysis showed that T allele in the MMP-9 promoter −1562 C/T polymorphism might be a protective factor for CP, especially in Caucasians and Asians. Moreover, there was a significant association of the MMP-9 promoter −1562 C/T polymorphism with decreased susceptibility to severe CP, while the allelic and/or genotype distributions of this polymorphism were not associated with moderate CP.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-2135-3) contains supplementary material, which is available to authorized users.

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

We aimed to systematically investigate the potential association of matrix metalloproteinase (MMP)-9, -3, -2, and -8 gene polymorphisms with susceptibility to periodontitis using meta-analysis. A literature search in PubMed, Embase, and Web of Science was conducted to obtain relevant publications. Finally a total of 16 articles with 24 case-control studies (nine on MMP-9-1562 C/T, seven on MMP-3-1171 A5/A6, four on MMP-2-753C/T, and four on MMP-8-799 C/T) were considered in this meta-analysis. The results based on 2,724 periodontitis patients and 3,438 controls showed that MMP-9-1562C/T, MMP-3-1171 A5/A6, and MMP-8-799C/T polymorphisms were associated with periodontitis susceptibility. No significant association was found between MMP-2-753 C/T and periodontitis susceptibility. Subgroup analyses suggested that the MMP-9-1562 C/T polymorphism reduced chronic periodontitis susceptibility and MMP-3-1171 A5/A6 polymorphism increased chronic periodontitis susceptibility. In summary, current evidence demonstrated that MMP-9-753 C/T polymorphism reduced the risk of periodontitis, MMP-3-1171 5A/6A and MMP-8-799 C/T polymorphisms increased the risk of periodontitis, and MMP-2-753 C/T was not associated with risk of periodontitis.

Association of Common Variants in MMPs with Periodontitis Risk

Background. Matrix metalloproteinases (MMPs) are considered to play an important role during tissue remodeling and extracellular matrix degradation. And functional polymorphisms in MMPs genes have been reported to be associated with the increased risk of periodontitis. Recently, many studies have investigated the association between MMPs polymorphisms and periodontitis risk. However, the results remain inconclusive. In order to quantify the influence of MMPs polymorphisms on the susceptibility to periodontitis, we performed a meta-analysis and systematic review. Results. Overall, this comprehensive meta-analysis included a total of 17 related studies, including 2399 cases and 2002 healthy control subjects. Our results revealed that although studies of the association between MMP-8 −799 C/T variant and the susceptibility to periodontitis have not yielded consistent results, MMP-1 (−1607 1G/2G, −519 A/G, and −422 A/T), MMP-2 (−1575 G/A, −1306 C/T, −790 T/G, and −735 C/T), MMP-3 (−1171 5A/6A), MMP-8 (−381 A/G and +17 C/G), MMP-9 (−1562 C/T and +279 R/Q), and MMP-12 (−357 Asn/Ser), as well as MMP-13 (−77 A/G, 11A/12A) SNPs are not related to periodontitis risk. Conclusions. No association of these common MMPs variants with the susceptibility to periodontitis was found; however, further larger-scale and multiethnic genetic studies on this topic are expected to be conducted to validate our results.

Host response mechanisms in periodontal diseases

Periodontal diseases usually refer to common inflammatory disorders known as gingivitis and periodontitis, which are caused by a pathogenic microbiota in the subgingival biofilm, including Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Treponema denticola that trigger innate, inflammatory, and adaptive immune responses. These processes result in the destruction of the tissues surrounding and supporting the teeth, and eventually in tissue, bone and finally, tooth loss. The innate immune response constitutes a homeostatic system, which is the first line of defense, and is able to recognize invading microorganisms as non-self, triggering immune responses to eliminate them. In addition to the innate immunity, adaptive immunity cells and characteristic cytokines have been described as important players in the periodontal disease pathogenesis scenario, with a special attention to CD4⁺ T-cells (T-helper cells). Interestingly, the T cell-mediated adaptive immunity development is highly dependent on innate immunity-associated antigen presenting cells, which after antigen capture undergo into a maturation process and migrate towards the lymph nodes, where they produce distinct patterns of cytokines that will contribute to the subsequent polarization and activation of specific T CD4+ lymphocytes. Skeletal homeostasis depends on a dynamic balance between the activities of the bone-forming osteoblasts (OBLs) and bone-resorbing osteoclasts (OCLs). This balance is tightly controlled by various regulatory systems, such as the endocrine system, and is influenced by the immune system, an osteoimmunological regulation depending on lymphocyte- and macrophage-derived cytokines. All these cytokines and inflammatory mediators are capable of acting alone or in concert, to stimulate periodontal breakdown and collagen destruction via tissue-derived matrix metalloproteinases, a characterization of the progression of periodontitis as a stage that presents a significantly host immune and inflammatory response to the microbial challenge that determine of susceptibility to develop the destructive/progressive periodontitis under the influence of multiple behavioral, environmental and genetic factors.

Is there any genetic predisposition of MMP-9 gene C1562T and MTHFR gene C677T polymorphisms with essential hypertension?

The current study was conducted to determine whether there is a relation between hypertension and two different polymorphisms, including C1562T of the Matrix metalloproteinase-9 (MMP-9) gene and C677T of the methylenetetrahydrofolate reductase (MTHFR) gene. Genomic DNA obtained from 224 persons (125 patients with hypertension and 99 healthy controls) were used in the study. Polymorphisms were determined by using polymerase chain reaction-restriction fragment length polymorphism and electrophoresis. The results were statistically analyzed and were found to be statistically significant. The frequencies of the C1562T genotypes were found to be, in controls CC 75.8 % and CT 24.2 % and in patients CC 71.2 %, and CT 28.8 %. The frequencies of C677T genotype were found to be, in controls CC 56.6 %, CT 38.4 and TT 5.1 % in controls and in patients CC 52 %, CT 30.4 % and TT 17.6 %. In conclusion, we may suggest that there is no relation between the essential hypertension and C1562T polymorphism of MMP-9 gene; on the other hand C677T polymorphism (genotype TT) of MTHFR gene can be regarded as a genetic indicator for the development of essential hypertension.

Toll-like receptor (TLR) and matrix metalloproteinase (MMP) polymorphisms and periodontitis susceptibility: a meta-analysis

The aim of this study was to determine whether the toll-like receptor (TLR) and matrix metalloproteinase (MMP) polymorphisms confers susceptibility to periodontitis in ethnically different populations. A literature search using PubMed and Embase provided the data to conduct a meta-analysis on the associations between the TLR2 Arg753Gln, TLR4 Asp299Gly, Thr399Ile, MMP-1 -1607 G1/G2 and MMP-9 -1562 C/T polymorphisms and periodontitis. A total of 32 studies (14 on TLR polymorphisms and 18 on MMP polymorphisms) were considered in the meta-analysis. The meta-analysis showed no association between periodontitis and the TLR2 753Arg allele (Odds ratio [OR]=0.962, 95% confidence interval [CI]=0.662-1.400, p=0.841). Meta-analysis of the TLR4 Asp299Gly and Thr399Ile polymorphisms showed no association between periodontitis and the TLR4 299Asp allele in all study subjects (OR=0.984, 95% CI=0.761-1.271, p=0.900; OR=1.030, 95% CI=0.748-1.418, p=0.854). Meta-analysis showed an association between the MMP-1 -1607 G2G2 genotype and periodontitis in Asians (OR=3.778, 95% CI=1.210-11.80, p=0.022). Meta-analysis containing only studies in Hardy-Weinberg equilibrium revealed no association between chronic periodontitis and the MMP-9 -1562TT genotype (OR=0.638, 95% CI=0.265-1.533, p=0.315). This meta-analysis demonstrates a lack of association between the TLR2 Arg753Gln, TLR4 Asp299Gly, Thr399Ile, MMP-9 -1562 C/T polymorphisms and periodontitis, but shows an association between the MMP-1 -1607 G2G2 genotype and periodontitis in Asians.

MMP-9 -1562C>T contributes to periodontitis susceptibility

AIM

The study was conducted to explore the potential association of Matrix metalloproteinases (MMP)-9 -1562C>T with susceptibility to periodontitis.

MATERIALS AND METHODS

Electronic literature searches of PubMed, EMBASE and EBSCO databases were performed. Fixed-effects or random-effects models were used to calculate the pooled odds ratios (ORs) for four genetic comparisons.

RESULTS

Seven eligible studies with a total of 628 cases and 689 controls were recruited in the pooled analysis. We found MMP-9 -1562C>T contributed to decreased risk of chronic periodontitis. Furthermore, the polymorphism was associated with modified risk of periodontitis among Caucasian populations.

CONCLUSIONS

This study indicated that MP-9 -1562C>T might be involved in the development of periodontitis. A replication of our results in independent large analysis populations is necessary to give evidence to our observation.

Lymphotoxin-Alpha Gene Polymorphism +252A/G (rs909253, A/G) Is Associated with Susceptibility to Chronic Periodontitis: A Pilot Study

Background. Periodontal disease leading to clinical findings such as increased periodontal probing depth involves a complex interaction between invading pathogenic microorganisms and the patient's immune system. Lymphotoxin alpha (LT-α) is a potent multifunctional immune modulator that contributes toward susceptibility to immune regulation disorders, including periodontal disease. Objective. In this study, we tested the hypothesis that chronic periodontitis (CP) is associated with polymorphisms of the LT-α gene. Materials and Methods. A total of 126 subjects, 44 healthy subjects, and 82 subjects with CP, were evaluated for periodontal disease by measuring clinical attachment loss and separation. Samples of epithelial cells were obtained for DNA analysis by scraping of the buccal mucosa. The LT-α gene was analyzed by polymerase chain reaction followed by endonuclease digestion with NcoI to analyze restriction fragment length polymorphisms. Results. The LT-α gene (+252A/G) polymorphism was associated with CP. LT-α allele frequencies were significantly different (P = 0.0019) between patients with CP and healthy individuals, with an odds ratio of 2.67 for patients with CP with the G allele. Conclusions. These findings suggest the LT-α gene genotype is a risk indicator for susceptibility to chronic periodontal disease in the Brazilian population studied.

Genetic polymorphism studies in periodontitis and Fcγ receptors

Periodontitis is a complex chronic subgingival plaque-induced inflammatory disease influenced by multiple factors, including genetics, behavior and the environment. Many genetic association studies have been conducted in periodontology. One of the most extensively investigated gene families is the Fcγ receptor gene family, which plays a key role in regulating host immune responses to bacteria. Unlike other genetic polymorphisms reported in periodontology, most Fcγ receptor polymorphisms reported not only have established biological functions but are reported to associate with other autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. There are, however, few recent reviews summarizing the association of this gene family with periodontitis. This article critically reviews the current understanding of genetic polymorphism studies in periodontitis, then summarizes the research status of Fcγ receptor polymorphisms and periodontitis and also of other genes involved in the regulatory network of Fcγ receptors, with special reference to their anticipated biological roles. Moreover, some possible future research directions in the related area are discussed.

Gene polymorphisms in chronic periodontitis

We aimed to conduct a review of the literature for gene polymorphisms associated with chronic periodontitis (CP) susceptibility. A comprehensive search of the literature in English was performed using the keywords: periodontitis, periodontal disease, combined with the words genes, mutation, or polymorphism. Candidate gene polymorphism studies with a case-control design and reported genotype frequencies in CP patients were searched and reviewed. There is growing evidence that polymorphisms in the IL1, IL6, IL10, vitamin D receptor, and CD14 genes may be associated with CP in certain populations. However, carriage rates of the rare (R)-allele of any polymorphism varied considerably among studies and most of the studies appeared under-powered and did not correct for other risk factors. Larger cohorts, well-defined phenotypes, control for other risk factors, and analysis of multiple genes and polymorphisms within the same pathway are needed to get a more comprehensive insight into the contribution of gene polymorphisms in CP.

The association of MMP-9 and IL-18 gene promoter polymorphisms with gingivitis in adolescents

OBJECTIVE

Interleukin 18 (IL-18) is shown to be a proinflammatory cytokine that regulates the expression of matrix metalloproteinase 9 (MMP-9). The aim of this study was to test for differences between Czech adolescents with and without gingivitis in relation to MMP-9 and IL-18 polymorphisms.

DESIGN

A total of 298 Caucasian children, aged 11-13 years, were examined to assess gingival health. DNA for genetic analysis was obtained from buccal epithelial cells, and the MMP-9 -1562C/T and IL-18 -607A/C variants were identified with PCR-RFLP.

RESULTS

Gingivitis was present in 49.3% of the adolescents examined, the rest of the group was considered healthy. The IL-18 -607C and MMP-9 -1562T alleles were found in 58.9% and 8.3% of the healthy subjects, and in 62.2% and 15.0% of the patients with gingivitis, respectively. Although differences in allele frequencies were not significant for IL-18 variant, they were significant for MMP-9 polymorphism (p=0.01, p(corr) < 0.05). Furthermore, a highly significant association of the composite genotype (formed by the variants of the both genes) with gingivitis was found (p=0.004, p(corr) < 0.05).

CONCLUSIONS

The -1562 T allele of MMP-9 gene could have a role in gingivitis in adolescents. In addition, interaction of the MMP-9 and IL-18 genes could be considered a risk factor for the development of gingivitis in children.

The broad effects of the functional IL-10 promoter-592 polymorphism: modulation of IL-10, TIMP-3, and OPG expression and their association with periodontal disease outcome

Periodontal diseases are infectious diseases, in which periodontopathogens trigger chronic inflammatory and immune responses that lead to tissue destruction. It occurs through the generation of metalloproteinases and the activation of bone resorption mechanisms. Anti-inflammatory cytokines such as IL-10 seem to attenuate periodontal tissue destruction through the induction of tissue inhibitors of metalloproteinases (TIMPs) and the inhibitor of osteoclastogenesis osteoprotegerin (OPG). A high individual variation in levels of IL-10 mRNA is verified in periodontitis patients, which is possibly determined by genetic polymorphisms. In this study, the IL-10 promoter -592C/A single nucleotide polymorphism (SNP), which is associated with a decrease in IL-10 production, was analyzed by RFLP in 116 chronic periodontitis (CP) patients and 173 control (C) subjects, and the IL-10, TIMPs, and OPG mRNA expression levels in diseased gingival tissues were determined by real-time-PCR. The IL-10-592 SNP CA (P=0.0012/OR=2.4/CI:1.4-4.1), AA (P=0.0458/OR=2.3/CI:1.1-4.9), and CA+AA (P=0.0006/OR=2.4/CI:1.4-3.4) genotypes and the allele A (P=0.0036/OR=1.7/CI:1.2-2.4) were found to be significantly more prevalent in the CP group when compared with control subjects. Both CA and AA genotypes were associated with lower levels of IL-10, TIMP-3, and OPG mRNA expression in diseased periodontal tissues and were also associated with disease severity as mean pocket depth. Taken together, the results presented here demonstrate that IL10-592 SNP is functional in CP, being associated with lower levels of IL-10 mRNA expression, which is supposed to consequently decrease the expression of the downstream genes TIMP-3 and OPG, and influence periodontal disease outcome.

The influence of type I diabetes mellitus on the expression and activity of gelatinases (matrix metalloproteinases-2 and -9) in induced periodontal disease

BACKGROUND AND OBJECTIVE

Periodontal disease corresponds to a group of lesions that affect the tooth-supporting tissues present in the dental follicle. Although bacterial plaque is important, the immune response also contributes to the destruction of periodontal tissues. Diabetes mellitus is closely associated with the development, progression and severity of periodontal disease because it not only affects extracellular matrix organization but also the tissue response to inflammation. The objective of the present investigation was to study the influence of diabetes on experimental periodontal disease by evaluating the degradation of extracellular matrix through the analysis of matrix metalloproteinase (MMP)-2 and MMP-9 expression and activity, using immunofluorescence, zymography and real-time reverse transcription-polymerase chain reaction.

MATERIAL AND METHODS

Wistar rats were divided into normal and diabetic groups and evaluated 0, 15 and 30 d after the induction of periodontal disease by ligature.

RESULTS

MMP-2 and -9 were detected in epithelial cells, in the blood vessel endothelium and in connective tissue cells. The same profile of enzymatic expression of MMP-2 and -9 was observed in normal and diabetic animals, with a peak in activity at day 15 of inflammation. However, in diabetic animals, MMP-2 gelatinolytic activity was reduced after the inflammatory stimulus, whereas that of MMP-9 was increased. MMP-2 gene expression decreased with inflammation in both normal groups and groups with diabetes. In contrast, MMP-9 expression increased in normal animals and decreased in diabetic animals after inflammation.

CONCLUSION

The results suggest the involvement of MMP-2 and -9 in the dynamics of periodontal disease and that variation in their expression levels results in differences in tissue organization and wound healing in normal and diabetic animals.

Matrix metalloproteinase-2, -9, and -12 gene polymorphisms in generalized aggressive periodontitis

BACKGROUND

Matrix metalloproteinases (MMPs) are involved in periodontal tissue remodeling and degradation. Polymorphisms in the promoter region of the MMP-2 and -9 genes and in the coding region of the MMP-12 gene could affect transcription and the function of these enzymes. The aim of the present study was to determine the association between the aforementioned MMP polymorphisms and generalized aggressive periodontitis (GAgP).

METHODS

Genomic DNA was obtained from the peripheral blood of 92 subjects with GAgP and 157 periodontally healthy subjects. MMP-2 -735C/T, MMP-9 -1562C/T, and MMP-12 357Asn/Ser polymorphisms were genotyped by polymerase chain reaction and restriction fragment length polymorphism. Probing depth, clinical attachment loss, supragingival plaque accumulation, and bleeding on probing were recorded. The data were analyzed by chi(2), logistic regression, and Mann-Whitney U tests.

RESULTS

The genotype distributions, allele frequencies, and rare allele carriage of MMP-2 and MMP-12 genes were similar in GAgP and healthy subjects (P >0.05). T allele frequency and T allele carriage of the MMP-9 -1562 C/T polymorphism were significantly lower in the GAgP group than in the healthy group (P <0.05). In addition, logistic regression analysis revealed a protective effect for MMP-9 -1562 T allele carriers (odds ratio = 0.52; P = 0.04).

CONCLUSIONS

MMP-2 -735C/T and MMP-12 357Asn/Ser polymorphisms are not related to GAgP. Conversely, the MMP-9 -1562 gene T allele might be associated with a decreased risk for GAgP in the Turkish population.

Morphologic evaluation and expression of matrix metalloproteinases-2 and 9 and nitric oxide during experimental periodontal disease in rat

The immunopathologic and inflammatory mechanisms involved in periodontal disease (PD) include the participation of host resident, inflammatory cells and chemical mediators. Metalloproteinases (MMPs) and nitric oxide (NO) play essential role in extracellular matrix turnover of periodontal tissue destruction. In this study, by means of RT-PCR through semi-quantitative densitometric scanning methods, the expression of MMPs -2 and -9 and inducible NO synthase (iNOS) was temporally and spatially investigated during the destructive mechanisms of experimentally induced PD in rats. Samples from different periods were microscopically analyzed and compared with the contralateral side (control). Our results showed significant expression of MMP-9 and iNOS in tissues affected by PD, as compared with controls, three days after PD induction, simultaneously with the beginning of alveolar bone loss. At 7 days post induction, only the MMP-9 mRNA presented a significantly higher expression, as compared with the respective controls. Thus, in the rat ligature-induced PD, MMP-9 and iNOS might importantly participate in the early stages of the disease, including inflammatory cell migration, tissue destruction and alveolar bone resorption. Also, we may suggest that the exuberant presence of PMNs may be related to the important expression of iNOS and MMP-9 found at 3 days post induction.

Gene polymorphisms of matrix metalloproteinase-2, -9 and -12 in periodontal health and severe chronic periodontitis

AIM

Matrix metalloproteinases (MMPs) are involved in periodontal tissue remodeling and degradation. MMP polymorphisms could alter transcription and function of these enzymes. The aim of this study was to investigate MMP-2, MMP-9 and MMP-12 gene polymorphisms in relation to susceptibility to severe chronic periodontitis (CP).

METHODS

Genomic DNA was obtained from peripheral blood of 87 severe CP patients and 107 periodontally healthy subjects. MMP-2 -735C/T, MMP-9 -1562C/T and MMP -12357Asn/Ser gene polymorphisms were genotyped by polymerase chain reaction and restriction fragment length polymorphism. Probing depth, clinical attachment loss, supragingival plaque accumulation and bleeding on probing were recorded. The data were analyzed by chi-square, logistic regression and Mann-Whitney-U-tests.

RESULTS

The genotype distributions and allele frequencies of MMP-2, MMP-9 and MMP-12 genes were similar in CP and healthy subjects (p>0.05). Differences between rare allele carriage rates of CP and healthy groups regarding MMP-2, MMP-9 and MMP-12 gene polymorphisms were not significant (p>0.05). However, T allele carriers of MMP-9 -1562 gene had less risk for CP (OR=0.36; 95% CI=0.16-0.81).

CONCLUSION

These data suggest that MMP-2 -735C/T, MMP-9 -1562C/T and MMP-12 357Asn/Ser polymorphisms are not associated with susceptibility to severe CP in Turkish population. However, T allele of MMP-9 -1562 gene might be associated with decreased susceptibility to severe CP.

Tissue inhibitor of metalloproteinase-2 G-418C polymorphism is associated with an increased risk of gastric cancer in a Chinese population

AIMS

To examine the effect of the TIMP-2 G-418C polymorphism on gastric cancer risk.

METHODS

We conducted a hospital-based, case-control study using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in 412 individuals (206 gastric cancer patients and 206 age, sex matched cancer-free controls).

RESULTS

The genotype and allele frequencies were significantly different (P = 0.007 and 0.005, respectively) between cases and controls. Further analysis showed that the variant TIMP-2 genotypes (CC+GC) had a 51% increased risk of gastric cancer compared with GG [adjusted odds ratio (OR) 1.51, 95% confidence interval (CI) 1.00-2.26, P = 0.049]. The elevated gastric cancer risk was especially evident in younger individuals (age < 58 years old) (adjusted OR 2.21, 95% CI 1.18-4.16) and smokers (adjusted OR 2.61, 95% CI 1.01-6.72). However, no significant association was observed between the variant genotypes and clinicopathological features of gastric cancer.

CONCLUSIONS

These findings suggest that the TIMP-2 G-418C polymorphism is a genetic predisposing factor for gastric cancer.

Prevalence of OPG and IL-1 gene polymorphisms in chronic periodontitis

AIM

To investigate the association of polymorphisms in the osteoprotegerin (OPG) and interleukin 1 (IL-1) genes with chronic periodontitis (CP).

MATERIAL AND METHODS

One hundred and ninety-four individuals (97 CP patients, 97 controls) were genotyped for the OPG polymorphisms Lys3Asn and Met256Val and for the IL-1 polymorphisms IL-1A (-889C/T) and IL-1B (+3953C/T).

RESULTS

The homozygous variants coding for Lys3 were present at a higher frequency, whereas Asn3 and Met256 were present at a lower frequency in CP patients/controls (Lys3: 31%/25%, Asn3: 23%/32% and Met256: 66%/73%). Heterozygosity for Lys3Asn was observed at a higher frequency in CP patients/controls (46%/43%). Homozygosity for the Val256 genotype was observed in two CP patients (one in controls). Met256Val heterozygosity was more prevalent in CP patients/controls (32%/20%). All differences were statistically not significant between CP patients and controls. In contrast, both IL-1 polymorphisms were statistically significant. The heterozygous variant for IL-1A was present in 32% of the CP patients and in 20% of the controls (homozygosity (patients/controls) CC: 10%/21% and TT: 55%/33%). Heterozygosity for IL-1B was observed in 37% of the CP patients versus 34% in the controls (homozygosity (patients/controls) CC: 26%/57% and TT: 37%/9%).

CONCLUSION

While the association between the IL-1 polymorphisms and CP was confirmed, no association between the OPG polymorphisms and CP could be found.

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

BACKGROUND

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Clinicopathological significance of MMP-2 and TIMP-2 genotypes in gastric cancer

AIMS

Single nucleotide polymorphisms in matrix metalloproteinase-2 (MMP-2) -1306 C/T and tissue inhibitor of metalloproteinase-2 (TIMP-2) -418 G/C abolish the Sp-1 binding site and down-regulate expression of these genes. We aim to elucidate the role of MMP-2 and TIMP-2 in clinicopathological manifestations of gastric cancer.

METHODS

We enrolled 240 gastric cancer patients and 283 controls. DNA was extracted from peripheral blood leucocytes. MMP-2 and TIMP-2 genotypes were analysed by PCR-direct sequencing and PCR-RFLP method, respectively.

RESULTS

MMP-2 and TIMP-2 genotypes were not associated with gastric cancer development. However, patients with MMP-2 -1306 C/C genotype showed higher risk of lymphatic invasion (odds ratio (OR)=2.77, p=0.01) and venous invasion (OR=2.93, p=0.012). TIMP-2 G/G genotype was associated with serosal invasion (OR=1.89, p=0.009), lymph node metastasis (OR=2.19, p=0.021), lymphatic invasion (OR=2.87, p=0.016) and venous invasion (OR=2.65, p=0.033).

CONCLUSION

Our results suggest MMP-2 and TIMP-2 genotypes play a crucial role in gastric cancer invasion, but not with development of gastric cancer.

Heterogeneity in the collagen-degrading ability ofPorphyromonas gingivalis-stimulated human gingival fibroblasts

BACKGROUND AND OBJECTIVE

The purpose of this study was to characterize the heterogeneity of the collagen-degrading ability of different human gingival fibroblast cell lines treated with Porphyromonas gingivalis supernatant.

MATERIAL AND METHODS

Seven human gingival fibroblast cell lines were analyzed for their ability to cleave Type I collagen in the presence and absence of culture supernatant from P. gingivalis ATCC 33277 (10% v/v). The matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) produced by these human gingival fibroblasts were monitored at the protein level by zymography and/or western blot analyses, as well as at the mRNA level by reverse transcription-polymerase chain reaction.

RESULTS

The collagen-degrading ability of the human gingival fibroblasts increased in four cell lines (aggressive) and was only slightly altered in the other three cell lines (nonaggressive) in the presence of P. gingivalis supernatant. MMP-1, MMP-2, and MMP-3 more readily underwent activation while the TIMP-1 level was decreased in the conditioned media from a P. gingivalis-treated human gingival fibroblast aggressive cell line. None of these was altered in a nonaggressive cell line. The mRNA levels of the MMPs and TIMPs were only slightly different between these two cell lines.

CONCLUSION

Heterogeneity exists in human gingival fibroblasts in regard to their collagenolytic activity in the presence of P. gingivalis.

Functional Polymorphisms in the Matrix Metalloproteinase-9 Gene in Relation to Severity of Chronic Periodontitis

BACKGROUND

Members of the matrix metalloproteinase (MMP) family are implicated in the chronic remodeling in periodontal diseases. Therefore, we performed a case-control study to investigate a plausible association between susceptibility to chronic periodontitis (CP) and the polymorphisms in the MMP-9 (gelatinase B) gene.

METHODS

Using polymerase chain reaction with subsequent restriction analyses, MMP-9 -1562C/T and R+279Q variants were determined in 304 subjects (169 patients with CP, 76 with a mild to moderate form and 93 with severe generalized CP, and 135 age- and gender-matched unrelated control subjects).

RESULTS

The distribution of the MMP-9 -1562C/T and R+279Q genotypes and alleles did not significantly differ between cases and controls. However, the frequency of the T variant at position -1562 was marginally higher in patients with severe disease compared to those with mild to moderate forms (P <0.05; P(corr) >0.05). In further analysis, the -1562T allele was associated with a severe form of CP in men (odds ratio: 3.87; 95% confidence interval: 1.40 to 10.65; P <0.01 and P(corr) <0.05 for allele; P <0.05 and P(corr) >0.05 for genotype) but not in women.

CONCLUSION

These findings suggest that genetic polymorphisms of the MMP-9 gene are not associated with the susceptibility to CP in the Czech population; however, the promoter variant may influence the severity of the disease in men.

Association of Matrix Metalloproteinase-9 Promoter Gene Polymorphism With Chronic Periodontitis

BACKGROUND

Matrix metalloproteinases (MMPs) are related to tissue destruction and remodeling events in periodontal diseases. A single nucleotide polymorphism in the promoter region of human MMP-9 gene is associated with the risk of some inflammatory diseases. Therefore, the aim of this study was to investigate the association between MMP-9 promoter polymorphism and severe generalized chronic periodontitis in a Turkish population.

METHODS

Samples of venous blood and DNA were obtained from 70 severe generalized chronic periodontitis patients and 70 healthy subjects. The alleles of the C/T polymorphism at position -1562 in the promoter region of the MMP-9 gene were distinguished by cutting with the SphI restriction enzyme. Genotype and allele frequencies were calculated, and data were analyzed by the chi2 test.

RESULTS

There was a significant difference in MMP-9 genotypes between chronic periodontitis patients and healthy controls. The odds ratios for the CT genotype and the combination of CT and TT genotypes were 0.4 (95% confidence interval, 0.17 to 0.93; P=0.02) and 0.37 (95% confidence interval, 016 to 0.85; P=0.01) relative to the subjects with the CC genotype, respectively.

CONCLUSION

MMP-9 promoter gene polymorphism seems to be associated with severe generalized chronic periodontitis.

Matrix metalloproteinases: contribution to pathogenesis, diagnosis and treatment of periodontal inflammation

Matrix metalloproteinases (MMPs) form a family of enzymes that mediate multiple functions both in the tissue destruction and immune responses related to periodontal inflammation. The expression and activity of MMPs in non-inflamed periodontium is low but is drastically enhanced to pathologically elevated levels due to the dental plaque and infection-induced periodontal inflammation. Soft and hard tissue destruction during periodontitis and peri-implantitis are thought to reflect a cascade of events involving bacterial virulence factors/enzymes, pro-inflammatory cytokines, reactive oxygen species and MMPs. However, recent studies suggest that MMPs can also exert anti-inflammatory effects in defence of the host by processing anti-inflammatory cytokines and chemokines, as well as by regulating apoptotic and immune responses. MMP-inhibitor (MMPI)-drugs, such as doxycycline, can be used as adjunctive medication to augment both the scaling and root planing-treatment of periodontitis locally and to reduce inflammation systematically. Furthermore, MMPs present in oral fluids (gingival crevicular fluid (GCF), peri-implant sulcular fluid (PISF), mouth-rinses and saliva) can be utilized to develop new non-invasive, chair/bed-side, point-of-care diagnostics for periodontitis and dental peri-implantitis.

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

AIM

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

METHODS

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

RESULTS AND CONCLUSIONS

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