Matrix metalloproteinase 8 (MMP8) gene polymorphisms in chronic periodontitis

Glutathione S-transferase M1, T1, and P1 polymorphisms and periodontitis in a Caucasian population: a case-control study

BACKGROUND

Glutathione S-transferases (GSTs) play important roles in protecting cells against oxidative stress and toxic chemicals. This study aimed to investigate the distribution of GSTM1, GSTT1, and GSTP1 variants and their roles in periodontitis susceptibility in a Caucasian population.

METHODS

We analyzed 406 participants, including 204 healthy controls and 203 periodontitis patients. A multiplex polymerase chain reaction (PCR) approach was used to analyze GSTM1 and GSTT1 loci. GSTP1 variants were detected by PCR-haplotyping method in a subgroup of participants (N = 350). Chi-square or Fisher´s exact tests were used to compare genotypic and allelic differences. The Bonferroni method was applied to correct for multiple comparisons (pcorr).

RESULTS

The GSTM1 genotype distribution did not differ significantly between controls and periodontitis patients (p = 0.44). Additionally, the wild/null genotypes of GSTT1, Ile105Val and Ala114Val frequencies of GSTP1 were not significantly different between the two groups after correction for multiple comparisons (p = 0.05, p = 0.55, p = 0.02, pcorr>0.05, respectively). The GSTM1 and GSTP1 Ile105Val gene variants were similarly distributed between non-smokers and smokers in both groups (p = 0.38, p = 0.20, and p = 0.14, p = 0.35, respectively). However, the wild genotype of the GSTT1 and Ala114Ala variant of the GSTP1 genes were present more frequently in non-smoking periodontitis patients than in non-smoking controls (p = 0.03, pcorr>0.05, and p = 0.009, pcorr>0.05, respectively) although their frequencies did not differ between smoking periodontitis patients and smoking controls (p = 0.23, p = 0.68, respectively).

CONCLUSIONS

This study in a Czech Caucasian population did not confirm a highly significant association between GST gene variants and susceptibility to periodontitis, as previously reported by Arshad and colleagues in Pakistanis. However, a weak relationship between GSTT1 and GSTP1 rs1138272 polymorphisms and periodontitis in non-smokers was observed.

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.

Nociceptors regulate osteoimmune transcriptomic response to infection

Osteoimmune diseases, such as apical periodontitis, are prevalent, often painful, inflammatory conditions resulting in bone loss and reduced quality of life. There is growing evidence that the nociceptive fibers densely innervating affected tissues regulate disease progression; therefore, we hypothesized that nociceptors regulate the transcriptomic profile of the periapical osteolytic lesion in a mouse model of apical periodontitis. Male control and nociceptor-ablated mice underwent pulp exposures, and after 0, 7, or 14 days, total RNA from periapical tissues was submitted for sequencing and bioinformatic analysis. Pulp exposure triggers the differential expression of hundreds of genes over the course of infection. At 14 days post pulp exposure, 422 genes, including Tnf, Il1a, and Il1b, were differentially expressed between nociceptor-ablated and control mice with greater enrichment of biological processes related to inflammation in nociceptor-ablated mice. Nociceptor ablation regulates the transcriptomic profile of periapical lesions in a mouse model of apical periodontitis, shifting the gene expression profile to a greater enrichment of inflammatory genes, suggesting nociceptors play a role in the kinetics of the immune response. This newly uncovered neuro-immune axis and its mechanisms in apical periodontitis can be an important therapeutic target for the treatment of this prevalent disease.

Genetic Control of GCF Exudation: Innate Immunity Genes and Periodontitis Susceptibility

Chronic periodontitis is a bacterial infection associated with dentally adherent biofilm (plaque) accumulation and age-related comorbidities. The disease begins as an inflammatory exudate from gingival margins, gingival crevicular fluid (GCF) in response to biofilm lysine. After a week of experimental gingivitis (no oral hygiene), biofilm lysine concentration was linearly related to biofilm accumulation (plaque index) but to GCF as an arch-shaped double curve which separated 9 strong from 6 weak GCF responders (hosts). Host DNA was examined for single nucleotide polymorphisms (SNPs) of alleles reported in 7 periodontitis-associated genes. Across all 15 hosts, an adenine SNP (A) at IL1B-511 (rs16944), was significant for strong GCF (Fisher's exact test, p < 0.05), and a thymidine SNP (T) at IL1B+3954 (rs1143634) for weak GCF provided 2 hosts possessing IL6-1363(T), rs2069827, were included. The phenotype of IL1B+3954(T) was converted from weak to strong in one host, and of the non-T allele from strong to weak in the other (specific epistasis, Fisher's exact test, p < 0.01). Together with homozygous alternate or reference SNPs at IL10-1082 or CD14-260 in 4 hosts, all hosts were identified as strong or weak GCF responders. The GCF response is therefore a strong or weak genetic trait that indicates strong or weak innate immunity in EG and controllable or uncontrollable periodontal disease, dental implant survival and late-life comorbidities.

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.

Benefits of Antimicrobial Photodynamic Therapy as an Adjunct to Non-Surgical Periodontal Treatment in Smokers with Periodontitis: A Systematic Review and Meta-Analysis

The objective of this study was to analyze evidence of the clinical and microbiological benefits of antimicrobial photodynamic therapy (aPDT) adjunctive to scaling and root planing (SRP) in smokers with periodontitis. Randomized clinical trials (RCTs) were included, through an electronic search in PubMed/MEDLINE, LILACS, Web of Science, and the Cochrane Library for articles published in English until December 2022. The quality of the studies was assessed using the JADAD scale and the risk of bias was estimated using the Cochrane Collaboration assessment tool. Of the 175 relevant articles, eight RCTs were included. Of these, seven reported clinical results and five microbiological results, with a follow-up time of 3–6 months. A meta-analysis was performed for the probing depth (PD) reduction and clinical attachment level (CAL) gain at 3 and 6 months. The weighted mean differences (WMDs) and 95% confidence intervals (CIs) were counted for the PD and CAL. The overall effect for the PD reduction at 3 and 6 months (WMD = −0.80, 95% CI = −1.44 to −0.17, p = 0.01; WMD = −1.35, 95% CI = −2.23 to −0.46, p = 0.003) was in favor of aPDT. The CAL gain (WMD = 0.79, 95% CI = −1.24 to −0.35, p = 0.0005) was statistically significant at 6 months, in favor of aPDT. In these RCTs, aPDT was unable to demonstrate efficacy in reducing the microbial species associated with periodontitis. aPDT as an adjuvant to SRP improves the PD reduction and CAL gain more effectively than only SRP. RCTs are needed to establish standardized protocols with longer follow-up times in order to provide more results on aPDT adjunctive to SRP in smokers with periodontitis.

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.

Detection of latent forms of Mycobacterium avium subsp. paratuberculosis infection using host biomarker-based ELISAs greatly improves paratuberculosis diagnostic sensitivity

Bovine paratuberculosis (PTB) is a chronic granulomatous enteritis, caused by Mycobacterium avium subsp. paratuberculosis (MAP), responsible for important economic losses in the dairy industry. Current diagnostic methods have low sensitivities for detection of latent forms of MAP infection, defined by focal granulomatous lesions and scarce humoral response or MAP presence. In contrast, patent infections correspond to multifocal and diffuse types of enteritis where there is increased antibody production, and substantial mycobacterial load. Our previous RNA-Seq analysis allowed the selection of five candidate biomarkers overexpressed in peripheral blood of MAP infected Holstein cows with focal (ABCA13 and MMP8) and diffuse (FAM84A, SPARC and DES) lesions vs. control animals with no detectable PTB-associated lesions in intestine and regional lymph nodes. The aim of the current study was to assess the PTB diagnostic potential of commercial ELISAs designed for the specific detection of these biomarkers. The ability of these ELISAs to identify animals with latent and/or patent forms of MAP infection was investigated using serum from naturally infected cattle (n = 88) and non-infected control animals (n = 67). ROC analysis revealed that the ABCA13-based ELISA showed the highest diagnostic accuracy for the detection of infected animals with focal lesions (AUC 0.837, sensitivity 79.25% and specificity 88.06%) and with any type of histological lesion (AUC 0.793, sensitivity 69.41% and specificity 86.57%) improving on the diagnostic performance of the popular IDEXX ELISA and other conventional diagnostic methods. SPARC and MMP8 showed the highest diagnostic accuracy for the detection of animals with multifocal (AUC 0.852) and diffuse lesions (AUC 0.831), respectively. In conclusion, our results suggest that quantification of ABCA13, SPARC and MMP8 by ELISA has the potential for implementation as a diagnostic tool to reliably identify MAP infection, greatly improving early detection of MAP latent infections when antibody responses and fecal shedding are undetectable using conventional diagnostic methods.

IL-6: An endogenous activator of MMP-9 in preterm birth

Preterm birth or PTB (<37 weeks) is a heterogeneous phenotype with numerous biological pathways. The lack of explanation due to complex pathways, inconsistent observations indicates the need for employing the role of genetic determinants to anticipate the danger of PTB. In this present study, we investigated the possible gene-gene interaction of five SNPs with PTB and its association with total MMP-9 levels. A total of 510 recruitments (250 terms and preterm each) were made and were genotyped by Restriction Fragment length polymorphism (RFLP). Generalized Multifactor Dimensionality Reduction (GMDR) method was carried out for determining gene-gene interaction. ANOVA and t-test were used to identify the association of IL-6 polymorphism with PTB alone and correspondingly with PTB and low birth weight infants (i.e. < 2500 kg). The combination of IL-6 and MMP-9 and MMP-1, MMP-8 and MMP-9 polymorphism was selected through GMDR analysis concerning mothers with preterm and term birth (accuracy 0.5921 and 0.8030 with Cross-Validation Consistency (CVC) 10/10 respectively). Increased expression of MMP-9 was reported in cases in those mothers carrying IL-6 G allele, which was profoundly associated with PTB independently. IL-6 polymorphisms showed synergistic effects in terms of increased total MMP-9 levels in the present study.

In Vitro Homeostasis of Rat Oral Epithelial Cell Cultures Following Withdrawal of Periodontal Pathogens

Inflammation of periodontal tissues is the consequence of interaction between periodontal pathogens and immune system. This is associated with increased expression of inflammatory cytokines, which may exert destructive effect to the periodontal tissues when released over long period. The aim of this study was to chronologically track the homeostasis of oral keratinocytes following removal of periodontal pathogens. This was done by investigating expression of selected inflammatory markers and integrity of epithelial monolayers in vitro. Rat oral keratinocytes were stimulated with heat-killed Fusobacterium nucleatum and Porphyromonas gingivalis over 7-days then bacteria were washed away and epithelial cells re-cultured for 3-days. Expression of IL-1β, IL-6, and IL-8 was measured by ELISA while transcription of tissue inhibitor of metalloproteinase-1 (TIMP-1) and matrix metalloproteinase -8 (MMP-8) was measured by polymerase chain reaction before and after removal of bacteria. Integrity of epithelial sheet was investigated by using transepithelial electrical resistance. Data showed general downregulation of IL-1b, IL-6, and IL-8 associated with restoring transcription of TIMP-1 and MMP-8 to normal level following removal of bacteria from epithelial cultures. However, expression of IL-8 and MMP-8 remained significantly higher than unstimulated epithelial cells despite withdrawal of F. nucleatum and P. gingivalis respectively from oral keratinocytes cultures. In addition, integrity of epithelial barrier function remained compromised even after removal of P. gingivalis. Results suggest that even after three days following removal of periodontal pathogens, oral keratinocytes sustained persistent upregulation of certain inflammatory markers that could compromise integrity of epithelial barrier function.

Gene variability in matrix metalloproteinases in patients with recurrent aphthous stomatitis

BACKGROUND

The development of recurrent aphthous stomatitis (RAS), inflammatory disease of oral mucosa, is influenced by both environmental and genetic factors. The aim of this study was to investigate polymorphisms located in seven genes coding different types of matrix metalloproteinases (MMPs)-collagenases (MMP1, MMP8, and MMP13), gelatinases (MMP2 and MMP9), stromelysin (MMP3), and membrane-type metalloproteinase (MMP16) in patients with RAS and healthy controls.

METHODS

Totally, 223 subjects were included in this case-control study and their detailed anamnestic, clinical, and laboratory parameters were recorded. Seventy-seven patients with RAS and 146 controls were genotyped for seventeen polymorphisms in the MMPs genes using the real-time polymerase chain reaction (PCR) or PCR with restriction analysis.

RESULTS

Allele, genotype, and haplotype frequencies of the studied polymorphisms between RAS patients and controls were similar, except for allele distributions of MMP1 rs1144393, MMP9 rs3918242, and MMP16 rs10429371, which were different between patients with RAS and healthy controls (P = .023, P = .049 and P = .025, all P_corr  > 0.05, respectively). Moreover, the comparison of genotype frequencies (TT vs CC + CT) of the MMP16 rs10429371 variant showed a marginally significant difference between RAS patients and controls (P = .05, P_corr  > 0.05, OR = 1.68, 95% CI = 0.95-2.98).

CONCLUSIONS

No significant relationship between investigated polymorphisms in seven MMPs genes and RAS development in the Czech population was observed in this study.

Early intervention of peri-implantitis and periodontitis using a mouse model

BACKGROUND

Peri-implantitis is an inflammatory response to bacterial biofilm resulting in bone loss and can ultimately lead to implant failure. Because of the lack of predictable treatments available, a thorough understanding of peri-implantitis's pathogenesis is essential. The objective of this study is to evaluate and compare the response of acute induced peri-implantitis and periodontitis lesions after insult removal.

METHODS

Implants were placed in one-month-old C57BL/6J male mice eight weeks post extraction of their left maxillary molars. Once osseointegrated, ligatures were placed around the implants and contralateral second molars of the experimental groups. Controls did not receive ligatures. After one week, half of the ligatures were removed, creating the ligature-retained and ligature-removed groups. Mice were sacrificed at two time points, 5 and 14 days, from ligature removal. The specimens were analyzed via micro-computed tomography and histology.

RESULTS

By 5 and 14 days after ligature removal, the periodontitis group experienced significant bone gain, whereas the peri-implantitis group did not. Histologically, all implant groups exhibited higher levels of cellular infiltrate than any of the tooth groups. Osteoclast numbers increased in peri-implantitis and periodontitis ligature-retained groups and decreased following insult removal. Collagen was overall more disorganized in peri-implantitis than periodontitis for all groups. Peri-implantitis experimental groups revealed greater matrix metalloproteinase-8 and NF-kB levels than periodontitis.

CONCLUSIONS

Implants respond slower and less favorably to insult removal than teeth. Future research is needed to characterize detailed peri-implantitis disease pathophysiology.

Periodontal Infectogenomics

Periodontal diseases are chronic infectious disease in which the pathogenic bacteria initiate the host immune response leading to the destruction of tooth supporting tissue and eventually result in the tooth loss. It has multifactorial etiological factors including local, systemic, environmental and genetic factors. The effect of genetic factors on periodontal disease is already under extensive research and has explained the role of polymorphisms of immune mediators affecting disease response. The role genetic factors in pathogens colonisation is emerged as a new field of research as "infectogenomics". It is a rapidly evolving and high-priority research area now days. It further elaborates the role of genetic factors in disease pathogenesis and help in the treatment, control and early prevention of infection. The aim of this review is to summarise the contemporary evidence available in the field of periodontal infectogenomics to draw some valuable conclusions to further elaborate its role in disease pathogenesis and its application in the clinical practice. This will open up opportunity for more extensive research in this field.

Prevalence of MMP-8 gene polymorphisms in HIV-infected individuals and its association with HIV-associated neurocognitive disorder

Matrix metalloproteinases (MMPs) are well-known as mediators of neuroinflammation in HIV-associated neurocognitive disorder (HAND). Increased levels of MMP-8 have been observed in the HIV-infected patients. Thus, the aim of this study was to evaluate the association of MMP-8 gene polymorphisms with modulation of HAND severity and its prevalence in HIV-infected and healthy individuals. We enrolled a total of 150 HIV-infected individuals, 50 HAND patients, 100 HIV-infected and 150 healthy individuals. MMP-8 (-799C/T, +17C/G) polymorphisms were genotyped by PCR-RFLP. MMP-8 -799TT genotype and +17G allele showed the higher risk for modulation of HAND severity (OR=2.20, P=0.19; OR=1.97, P=0.23). MMP-8 -799TT genotype differed significantly in HIV-infected individuals compared to healthy controls (20.0% vs. 11.3%, OR=2.36, P=0.048). Haplotype TG increased the risk for modulation of HAND severity (OR=2.29, P=0.29). MMP-8 -799TT and +17CG genotypes were overrepresented in the intermediate HIV disease stage compared with healthy controls (25.9% vs. 11.3%, OR=4.34, P=0.021, 14.8% vs. 9.3%, OR=2.88, P=0.11). MMP-8 +17CG genotype enhanced the risk for modulation of HAND severity in tobacco using HAND patients (OR=5.01, P=0.17). MMP-8 -799TT genotype was more frequent in tobacco using HIV-infected individuals compared with nonusers (26.3% vs. 16.7%, OR=2.08, P=0.32). MMP-8 +17CG genotype increased the risk for modulation of HAND severity in alcohol using HAND patients (OR=4.99, P=0.18). In conclusion, MMP-8 polymorphisms independently and with alcohol and tobacco usage revealed a trend of higher risk for the modulation of HAND severity. MMP-8 -799TT genotype was associated with the advancement of HIV disease.

Interleukin-12-mediated expression of matrix metalloproteinases in human periodontal ligament fibroblasts involves in NF-κB activation

Interleukin-12 (IL-12) is a proinflammatory cytokine, and its increased level correlates with the severity of periodontitis. However, its role in the pathogenesis of tooth periapical lesions is controversial and has not been completely clarified. The present study aimed to investigate whether IL-12 affects the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in human periodontal ligament fibroblasts (hPDLFs). After treatment with IL-12 for different times, real-time PCR and Western blotting were used to determine the mRNA and protein levels of MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, TIMP-1, and TIMP-2, respectively. ELISA was applied to measure MMPs and TIMPs secretion production. The results indicated that IL-12 significantly increased the mRNA and protein expression levels of MMP-1, MMP-3, and MMP-13, but down-regulated MMP-2 and MMP-9 mRNA and protein expression in the hPDLFs. Furthermore, IL-12 (10 ng/ml) enhanced the secreted protein production of MMP-1, MMP-3, and MMP-13, and conversely lowered MMP-2 and MMP-9 secretion levels. However, IL-12 treatment did not exert a significant effect on the mRNA and protein levels of TIMP-1 and TIMP-2 and their secreted production. Additionally, IL-12 increased the phosphorylated levels of IκBα and nuclear factor-κB P65 (NF-κB P65), and promoted NF-κB P65 subunit nuclear translocation. Pretreatment with NF-κB inhibitor not only attenuated IL-12-induced IκBα and NF-κB P65 phosphorylation and inhibited NF-κB P65 subunit into nucleus, but also antagonized IL-12-mediated MMP-1, MMP-2, MMP-3, MMP-9, and MMP-13 expression in the hPDLFs. These findings indicate that NF-κB-dependent activation is possibly indispensable for IL-12-mediated MMP expression in hPDLFs.

Ligature-induced peri-implantitis and periodontitis in mice

AIM

Peri-implantitis (PI), inflammation around dental implants, shares characteristics with periodontitis (PD). However, PI is more difficult to control and treat, and detailed pathophysiology is unclear. We aimed to compare PI and PD progression utilizing a murine model.

MATERIALS AND METHODS

Four-week-old male C57BL/6J mice had their left maxillary molars extracted. Implants were placed in healed extraction sockets and osseointegrated. Ligatures were tied around the implants and second molars. Controls did not receive ligatures. Mice were sacrificed 1 week, 1 and 3 months (n ≥ 5/group/time point) post-ligature placement. Bone loss analysis was performed. Histology was performed for: haematoxylin and eosin (H&E), tartrate-resistant acid phosphatase (TRAP), matrix metalloproteinase-8 (MMP-8), nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), toluidine blue and calcein.

RESULTS

PI showed statistically greater bone loss compared to PD at 1 and 3 months. At 3 months, 20% of implants in PI exfoliated; no natural teeth exfoliated in PD. H&E revealed that alveolar bone surrounding implants in PI appeared less dense compared to PD. PI presented with increased osteoclasts, MMP-8 and NF-κB, compared to PD.

CONCLUSION

PI exhibited greater tissue and bone destruction compared to PD. Future studies will characterize the pathophysiological differences between the two conditions.

The function of dendritic cells in modulating the host response

Dendritic cells (DCs) are antigen-presenting cells that capture, process, and present antigens to lymphocytes to initiate and regulate the adaptive immune response. DCs detect bacteria in skin and mucosa and migrate into regional lymph nodes, where they stimulate antigen-specific T and B lymphocyte activation and proliferation. DCs direct CD4 T cells to differentiate to T-cell subsets such as T helper cells types 1, 2, and 17, and regulatory T cells. The periodontium is chronically exposed to oral bacteria that stimulate an inflammatory response to induce gingivitis or periodontitis. DCs play both protective and destructive roles through activation of the acquired immune response and are also reported to be a source of osteoclast precursors that promote bone resorption. FOXO1, a member of the forkhead box O family of transcription factors, plays a significant role in the activation of DCs. The function of DCs in periodontal inflammation has been investigated in a mouse model by lineage-specific deletion of FOXO1 in these cells. Deletion of FOXO1 reduces DC protective function and enhances susceptibility to periodontitis. The kinase Akt, phosphorylates FOXO1 to inhibit FOXO activity. Hence the Akt-FOXO1 axis may play a key role in regulating DCs to have a significant impact on periodontal disease.

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.

Trends in Laboratory Diagnostic Methods in Periodontology

This work presents a summary of current knowledge on the laboratory diagnosis of periodontitis. It focuses on the theoretical foundations and is supplemented with new knowledge. It subsequently describes specifically the laboratory diagnosis methods of periodontitis: the protein expression of inflammation, oral microbiology and molecular diagnostics. Periodontitis is a serious disease worldwide and its confirmed association with systemic diseases means its severity is increasing. Its laboratory diagnosis has the potential to rise to the level of clinical and diagnostic imaging. The transfer of diagnostic methods from laboratory to clinical use is increasingly used in the prevention and monitoring of the exacerbation and treatment of periodontal disease, as well as of its impact on systemic disease.

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 Sciencewas 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/A6polymorphism increased chronic periodontitis susceptibility. In summary, current evidence demonstrated that MMP-9-753 C/Tpolymorphism reduced the risk of periodontitis, MMP-3-1171 5A/6A and MMP-8-799 C/Tpolymorphisms 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.

Analysis of matrix metalloproteinase-8 levels in gingival crevicular fluid and whole mouth fluid among smokers and nonsmokers using enzyme-linked immune-sorbent assay and a novel chair-side test

AIM

To indigenously prepare a chair-side test kit for investigating and comparing the matrix metalloproteinase (MMP)-8 levels in gingival crevicular fluid (GCF) and saliva in patients with healthy periodontium, gingivitis and chronic periodontitis in smokers and nonsmokers. To validate the diagnostic accuracy of indigenously prepared chair-side test against enzyme-linked immune-sorbent assay (ELISA). Furthermore, to assess the effect of nonsurgical periodontal therapy (NSPT) on the levels of MMP-8 in GCF and saliva among the test groups.

MATERIALS AND METHODS

GCF and saliva were collected from 250 subjects. The study population were divided into five groups; health periodontium-nonsmokers (Group 1; n = 50), chronic gingivitis-nonsmokers (Group 2; n = 50), chronic periodontitis-nonsmokers (Group 3; n = 50), chronic gingivitis-smokers (Group 4; n = 50), chronic periodontitis-smokers (Group 5; n = 50). A chair-side test kit was indigenously prepared using polyclonal antibodies (principle of immunochromatography) to detect the MMP-8 levels, and it was validated against ELISA at baseline and 3 months after NSPT.

RESULTS

The chair-side test detected MMP-8 levels with a sensitivity and specificity in accordance with ELISA. MMP-8 levels at baseline were higher in Group 2 and Group 3 as compared to controls (P < 0.05), and decreased after therapy (P < 0.05). MMP-8 levels in GCF were greater than in saliva for all the groups, indicating GCF to be a better sample to detect the MMP levels.

CONCLUSION

The chair-side test detected MMP-8 levels accurately making it a viable chair side diagnostic tool. It was effective for early diagnosis of the periodontal disease among high-risk population such as smokers.

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.

Matrix metalloproteinase-8 promoter gene polymorphisms in Mexican women with ovarian cancer

Increased levels of matrix metalloproteinase-8 (MMP-8) have been associated with tumor grade and stage in ovarian cancer. Also, it has been reported that higher concentrations of this enzyme in fluid from malignant ovarian cysts compared with benign ovarian cysts. However, no genetic analysis has been conducted yet to assess the contribution of MMP-8 polymorphisms in ovarian cancer. Thus, this study was performed to investigate the frequencies of MMP-8 genotypes in Mexican women with ovarian cancer. MMP-8 promoter genotypes were examined in 35 malignant ovarian tumors, 51 benign tumors, and 37 normal ovary tissues. Two single nucleotide polymorphisms were selected and characterized using polymerase chain reaction-restriction fragment length polymorphism analysis. The chi-square test was used to calculate statistical significance. Haplotype analysis was performed using the SNPstats web tool. Of the two polymorphisms, only the MMP-8 -799 T/T genotype was significantly associated with an increased risk of ovarian cancer (OR 3.78, 95 % CI 1.18-12.13). The Kaplan-Meier analysis for this polymorphism showed that patients with the T/T genetic variant had a tendency toward significant worse overall survival compared with patients with the C/C + C/T genotypes. Haplotype analysis revealed no significant differences in haplotype distribution between benign ovarian tumors, malignant ovarian cancer, and controls. This study suggests that MMP-8 promoter gene polymorphism -799 T/T is significantly associated with an increased risk of ovarian cancer in Mexican women.