Cellular source, activation and inhibition of dental plaque collagenase

Correlations between different protein species of oral rinse MMP-8 and patient-related factors

OBJECTIVES

The aim of this study is to examine correlations between different oral rinse matrix metalloproteinase (MMP)-8 protein species in western blot (WB) analysis, quantitative MMP-8 measurements, and patient-related factors. Elevated activated MMP-8 (aMMP-8) associate with periodontitis and a diagnostic point-of-care technology has been developed based on aMMP-8. In WB, different MMP-8 protein species can be analyzed. Relative abundancy of fragmented 20-25 kDa forms in WB has been associated with and reflects MMP-8 activation and related fragmentation and elevated quantitative aMMP-8 measurements.

MATERIAL AND METHODS

A random sample of 192 participants from a periodontal disease screening study was used for this study. Oral rinse samples for biomarker analyses were collected before clinical periodontal examinations. aMMP-8 immunofluorometric (IFMA) and WB analysis (utilizing the same monoclonal antibody, 8708), polymorphonuclear leukocyte (PMN) elastase activity test and tissue inhibitor of metalloproteinases (TIMP)-1 ELISA levels were performed from the oral rinse samples. Distinct MMP-8 protein species were differentiated in the WB analysis. Principal component (PC) analysis was conducted to explore correlation patterns between the different species. Adjusted correlation analysis between the extracted PCs of WB and aMMP-8 IFMA levels and multilevel regression analysis were conducted to explore if the other periodontal disease-related biomarkers and clinical surrogate measures and patient-related factors are co-variating with the extracted components.

RESULTS

Distinct correlation patterns between the MMP-8 protein species were observed. The first four PCs explained 89% of the whole variance in PC analysis. Statistically significant correlation (p < 0.05) were observed as follows: PC1 positively with 21 kDa (r = .69) and 25 kDa fragments (r = .55) and negatively with 150 kDa complexes (r = -.46). PC2 correlated with 45 (r = .70) and 55 kDa (r = .65) activated forms, PC3 with 70-80 kDa latent proforms (r = .63) and 90-100 kDa complexes (r = .67), and PC4 with 35 kDa fragments (r = .81). There were significant correlations between quantitative (IFMA) aMMP-8 measurements and PC1 (p < 0.001), PC2 (<0.05) and PC3 (<0.05) but not with PC4. In multilevel regression models age, PMN elastase activity, TIMP-1 levels, and a number of 4-5 mm periodontal pockets were associated with PC1, nonsmoking with PC2, age and PMN elastase activity with PC3, and age and smoking with PC4.

CONCLUSIONS

Relative abundancy of fragmented 21-25 kDa protein species was correlated with the quantitative aMMP-8 (IFMA) measurements, which is in line with previous results. Different patient-related factors (smoking, age, proteolytic activity) may modify the formation of different MMP-8 protein species in oral rinse samples and may cause variability in quantitative aMMP-8 measurement.

An optical fiber-based point-of-care test for periodontal MMP-8 detection: a proof of concept

OBJECTIVES

The evaluation of salivary biomarkers has been proposed as a simple and non-invasive aid to the conventional periodontal diagnosis based on clinical-radiographic parameters. Matrix metalloproteinase-8 (MMP-8), especially in its active form, is considered one of the most reliable biomarkers of periodontitis, and point-of-care tests (POCTs) have been proposed for its clinical monitoring. In this proof-of-concept study, a novel highly sensitive POCT based on a plastic optical fiber (POF) biosensor exploiting surface plasmon resonance (SPR) to detect salivary MMP-8 is described.

METHODS

A SPR-POF biosensor was functionalized with a specific antibody to develop a surface-assembled monolayer (SAM) for the detection of total MMP-8. A white light source and a spectrometer connected to the biosensor were used to quantify MMP-8 level in both buffer and real matrix (saliva) by analysing the shift of the resonance wavelength determined by the specific antigen-antibody binding upon the SAM.

RESULTS

Dose-response curves by serial dilutions of human recombinant MMP-8 were realized, obtaining a limit of detection (LOD) of 40 pM (1.76 ng/ml) in buffer and 225 pM (9.9 ng/ml) in saliva and high selectivity compared to interferent analytes (MMP-2 and IL-6).

CONCLUSIONS

The proposed optical fiber-based POCT was able to detect and measure total MMP-8 with high selectivity and very low LOD in both buffer and saliva.

CLINICAL SIGNIFICANCE

The SPR-POF technology may be employed to create highly sensitive biosensors to monitor salivary MMP-8 levels. The possibility of specifically detecting its active, rather than total, form need to be further investigated. If confirmed and clinically validated, such a device may represent a promising tool to make an immediate, highly sensitive and reliable diagnosis of periodontitis, and to carry out a timely and targeted therapy, possibly helping to prevent the onset of local and systemic periodontitis-related complications.

Validation of a noninvasive aMMP‐8 point‐of‐care diagnostic methodology in COVID‐19 patients with periodontal disease

Objectives

The aim of this study was to validate an active matrix metalloproteinase (MMP‐8) point‐of‐care diagnostic tool in COVID‐19 patients with periodontal disease.

Subjects, Materials, and Methods

Seventy‐two COVID‐19‐positive and 30 COVID‐19‐negative subjects were enrolled in the study. Demographic data were recorded, periodontal examination carried out, and chairside tests run for evaluating the expression of active MMP‐8 (aMMP‐8) in the site with maximum periodontal breakdown via gingival crevicular fluid sampling as well as via a mouth rinse‐based kit for general disease activity. In COVID‐19‐positive patients, the kits were run again once the patients turned COVID‐19 negative.

Results

The overall (n = 102) sensitivity/specificity of the mouthrinse‐based kits to detect periodontal disease was 79.41%/36.76% and that of site‐specific kits was 64.71%/55.88% while adjusting for age, gender, and smoking status increased the sensitivity and specificity (82.35%/76.47% and 73.53%/88.24, respectively). Receiver operating characteristic (ROC) analysis for the adjusted model revealed very good area under the ROC curve 0.746–0.869 (p < .001) and 0.740–0.872 (p < .001) (the aMMP‐8 mouth rinse and site‐specific kits, respectively). No statistically significant difference was observed in the distribution of results of aMMP‐8 mouth rinse test (p = .302) and aMMP‐8 site‐specific test (p = .189) once the subjects recovered from COVID‐19.

Conclusions

The findings of the present study support the aMMP‐8 point‐of‐care testing (PoCT) kits as screening tools for periodontitis in COVID‐19 patients. The overall screening accuracy can be further increased by utilizing adjunctively risk factors of periodontitis. The reported noninvasive, user‐friendly, and objective PoCT diagnostic methodology may provide a way of stratifying risk groups, deciding upon referrals, and in the institution of diligent oral hygiene regimens.

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.

Active MMP-8 point-of-care (PoC)/chairside enzyme-test as an adjunctive tool for early and real-time diagnosis of peri-implantitis

Objective

The aim of this study was to investigate the utility of the active matrix metalloproteinase (aMMP‐8)‐point‐of‐care (PoC) test as a quantitative real‐time chair‐side diagnostic tool for peri‐implant diagnosis, as well as assess the potentially developing and ongoing risk relative to the traditional clinical methods.

Background

Current peri‐implant and periodontal disease diagnoses rely on clinical and radiological examinations. This case‐control study investigated the applicability of aMMP‐8‐PoC immunotest for quantitative real‐time diagnosis and monitoring of dental implants in health and disease.

Methods

Sixty‐eight patients visiting a specialist clinic for maintenance following dental implant placement underwent assessment of their peri‐implant health. aMMP‐8‐PoC peri‐implant sulcular fluid (PISF) lateral‐flow immunotests were performed using ImplantSafe® technology quantitated by ORALyzer®. In addition, the PISF samples were analyzed for total MMP‐8, calprotectin, and interleukin (IL)‐6 by enzyme‐linked immunosorbent assays (ELISA), aMMP‐8 by western immunoblot, and MMP‐2 and MMP‐9 by gelatin zymography.

Results

The aMMP‐8‐PoC test promptly recorded and reflected peri‐implant disease, differentiating it clearly from health. X‐ray findings (bone loss > 2 mm), peri‐implant pocket depth ≥ 3 mm, and bleeding on probing were significantly more prevalent among implants positive for the aMMP‐8‐PoC test. aMMP‐8/ORALyzer analysis was more precise in recording disease than total MMP‐8, calprotectin, IL‐6, MMP‐2, and MMP‐9.

Conclusions

The aMMP‐8‐PoC test can be conveniently implemented to alert for and detect active collagenolysis affecting peri‐implant tissues, both in the early and advanced stages of the disease. Active and fragmented MMP‐8 exhibits a strong and significant association with peri‐implantitis as compared to total MMP‐8 and other biomarkers and can be utilized as the POC/chairside biomarker of choice in the new classification of peri‐implantitis.

Active matrix metalloproteinase-8 (aMMP-8) point-of-care test (POCT) in the COVID-19 pandemic

INTRODUCTION

Active matrix metalloproteinase (aMMP)-8 utilized in point-of-care testing (POCT) is regarded as a potential biomarker for periodontal and peri-implant diseases. Various host and microbial factors eventually influence the expression, degranulation, levels and activation of aMMP-8. The type of oral fluids (saliva, mouthrinse, gingival crevicular, and peri-implant sulcular fluids [GCF/PISF], respectively) affect the analysis.

AREAS COVERED

With this background, we aimed to review here the recent studies on practical, inexpensive, noninvasive and quantitative mouthrinse and GCF/PISF chair-side POCT lateral flow aMMP-8 immunoassays (PerioSafe and ImplantSafe/ORALyzer) and how they help to detect, predict, monitor the course, treatment and prevention of periodontitis and peri-implantitis. The correlations of aMMP-8 POCT to other independent and catalytic activity assays of MMP-8 are also addressed.

EXPERT OPINION

The mouthrinse aMMP-8 POCT can also detect prediabetes/diabetes and tissue destructive oral side-effects due to the head and neck cancers' radiotherapy. Chlorhexidine and doxycycline can inhibit collagenolytic human neutrophil and GCF aMMP-8. Furthermore, by a set of case-series we demonstrate the potential of mouthrinse aMMP-8 POCT to real-time/online detect periodontitis as a potential risk disease for coronavirus disease 2019 (COVID-19). The clinical interdisciplinary utilization of aMMP-8 POCT requires additional oral, medical, and interdisciplinary studies.

Collagenolytic Enzymes and their Applications in Biomedicine

Nowadays, enzymatic therapy is a very promising line of treatment for many different diseases. There is a group of disorders and conditions, caused by fibrotic and scar processes and associated with the excessive accumulation of collagen that needs to be catabolized to normalize the connective tissue content. The human body normally synthesizes special extracellular enzymes, matrix metalloproteases (MMPs) by itself. These enzymes can cleave components of extracellular matrix (ECM) and different types of collagen and thus maintain the balance of the connective tissue components. MMPs are multifunctional enzymes and are involved in a variety of organism processes. However, under pathological conditions, the function of MMPs is not sufficient, and these enzymes fail to deal with disease. Thus, medical intervention is required. Enzymatic therapy is a very effective way of treating such collagen-associated conditions. It involves the application of exogenous collagenolytic enzymes that catabolize excessive collagen at the affected site and lead to the successful elimination of disease. Such collagenolytic enzymes are synthesized by many organisms: bacteria, animals (especially marine organisms), plants and fungi. The most studied and commercially available are collagenases from Clostridium histolyticum and from the pancreas of the crab Paralithodes camtschatica, due to their ability to effectively hydrolyse human collagen without affecting other tissues, and their wide pH ranges of collagenolytic activity. In the present review, we summarize not only the data concerning existing collagenase-based medications and their applications in different collagen-related diseases and conditions, but we also propose collagenases from different sources for their potential application in enzymatic therapy.

Associations of chairside salivary aMMP-8 findings with periodontal parameters, potentially periodontal pathogenic bacteria and selected blood parameters in systemically healthy adults

The aim of this cross-sectional study was to investigate associations between salivary active matrix-metalloproteinase 8 (aMMP-8) and periodontitis severity, potentially periodontal pathogenic bacteria as well as blood parameters in generally healthy participants. Therefore, 188 participants with a mean age of 48.9 ± 8 years were examined. The periodontitis severity was assessed based on periodontal probing depth and clinical attachment loss. Both, aMMP-8 and microbiological analysis were performed using a validated, commercially available test system. Blood values were utilized from regular differential blood count. The aMMP-8 findings were associated with the periodontitis severity (P < 0.01), as well as with the prevalence of Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, Parvimonas micra, Camphylobacter rectus and Eubacterium nodatum (P_i < 0.05). No associations between aMMP-8 and the examined blood parameters were found (P_i > 0.05). In conclusion, salivary aMMP-8 findings seem to reflect periodontal disease severity as a result of an immunoreaction, especially against bacteria with high periodontal pathogenic potential.

A New Controlled-Release Material Containing Metronidazole and Doxycycline for the Treatment of Periodontal and Peri-Implant Diseases: Formulation and In Vitro Testing

Background

Several locally administered antimicrobials have been studied in the literature as adjunctive or primary treatments for periodontitis and peri-implantitis with conflicting results.

Objective

The aim of this study was twofold: (1) the formulation of a controlled-release material containing metronidazole and doxycycline; (2) an in vitro evaluation of its antibacterial properties against planktonic and biofilm species involved in periodontal and peri-implant diseases.

Methods

Doxycycline (10 mg/ml) and metronidazole (20 mg/ml) were incorporated into a hydroxyethylcellulose-polyvinylpyrrolidone-calcium polycarbophil gel. Three milliliters of gel were dialyzed against Dulbecco's phosphate-buffered saline for 13 days. Antibiotics release at 3, 7, 10, and 13 days was determined spectroscopically. The inhibitory activity of the experimental gel was tested against A. actinomycetemcomitans, S. sanguinis, P. micra, and E. corrodens with an agar diffusion test, an inactivation biofilm test, and a confocal laser scanning microscope study (CLSMS) for S. sanguinis up to 20 days.

Results

After 13 days, the released doxycycline was 9.7% (at 3 days = 1.2 mg; 7 days = 0.67 mg; 10 days = 0.76 mg; 13 days = 0.29 mg), while metronidazole was 67% (30 mg, 6.8 mg, 2.5 mg, and 0.9 mg at the same intervals). The agar diffusion test highlights that the formulated gel was active against tested microorganisms up to 312 h. Quantitative analysis of biofilm formation for all strains and CLSMS for S. sanguinis showed a high growth reduction up to 13 days.

Conclusions

The in vitro efficacy of the newly formulated gel was confirmed both on planktonic species and on bacterial biofilm over a period of 13 days. The controlled-release gel containing metronidazole and doxycycline had an optimal final viscosity and mucoadhesive properties. It can be argued that its employment could be useful for the treatment of periodontal and peri-implant diseases, where conventional therapy seems not successful.

Matrix Metalloproteinase-8 as an Inflammatory and Prevention Biomarker in Periodontal and Peri-Implant Diseases

Levels of and especially the degree of activation of matrix metalloproteinase (MMP-8) in oral fluids (i.e., saliva, mouth rinse, gingival crevicular fluid (GCF) and peri-implantitis sulcular fluid (PISF)) increase to pathologically elevated levels in the periodontal and peri-implant diseases. This study aimed at collecting and collating data from previously published studies and determining whether active MMP-8 (aMMP-8) could serve as a biomarker for the diagnosis and prevention of periodontal and peri-implant diseases. The literature search identified a total of 284 articles. Out of 284 articles, 61 articles were found to be relevant. Data obtained from the selected studies were combined, and it indicated that aMMP-8 in oral fluids exerts the strong potential to serve as a useful adjunctive diagnostic and preventive biotechnological tool in periodontal and peri-implant diseases. aMMP-8 can be used alone or in combination with other proinflammatory and/or microbiological biomarkers.

Matrix metalloproteinase-8 levels in periodontal disease patients: A systematic review

Periodontal disease is characterized as a disorder of the oral microbiota resulting in an immune response which, in turn, leads to the destruction of periodontal tissue. Matrix metalloproteinase-8 (MMP-8) has been reported as the major metalloproteinase involved in periodontal disease, being present at high levels in gingival crevicular fluid and salivary fluid (SF). The aim of this systematic review was to evaluate the scientific literature regarding the expression of MMP-8 in gingival crevicular fluid and SF in patients with periodontal disease, analyzing its validity as a possible biomarker in the diagnosis of periodontal disease. A systematic review of the literature was performed using the PubMed/Medline, CENTRAL and Science Direct databases. Studies concerning the use of MMP-8 in the diagnosis of periodontal disease that evaluated its effectiveness as a biomarker for periodontal disease were selected. The search strategy provided a total of 6483 studies. After selection, six articles met all the inclusion criteria and were included in the present systematic review. The studies demonstrated significantly higher concentrations of MMP-8 in patients with periodontal disease compared with controls, as well as in patients presenting more advanced stages of periodontal disease. The findings on higher MMP-8 concentrations in patients with periodontal disease compared with controls imply the potential adjunctive use of MMP-8 in the diagnosis of periodontal disease.

Diagnosing peri-implant disease using the tongue as a 24/7 detector

Our ability of screening broad communities for clinically asymptomatic diseases critically drives population health. Sensory chewing gums are presented targeting the tongue as 24/7 detector allowing diagnosis by "anyone, anywhere, anytime". The chewing gum contains peptide sensors consisting of a protease cleavable linker in between a bitter substance and a microparticle. Matrix metalloproteinases in the oral cavity, as upregulated in peri-implant disease, specifically target the protease cleavable linker while chewing the gum, thereby generating bitterness for detection by the tongue. The peptide sensors prove significant success in discriminating saliva collected from patients with peri-implant disease versus clinically asymptomatic volunteers. Superior outcome is demonstrated over commercially available protease-based tests in saliva. "Anyone, anywhere, anytime" diagnostics are within reach for oral inflammation. Expanding this platform technology to other diseases in the future features this diagnostic as a massive screening tool potentially maximizing impact on population health.Early detection of gum inflammation caused by dental implants helps prevent tissue damage. Here, the authors present a peptide sensor that generates a bitter taste when cleaved by proteases present in peri-implant disease, embed it in a chewing gum, and compare the probe to existing sensors using patient saliva.

Genetic Association of MMP10, MMP14, and MMP16 with Dental Caries

Matrix metalloproteinases (MMPs), which degrade extracellular proteins as part of a variety of physiological processes, and their inhibitors have been implicated in the dental caries process. Here we investigated 28 genetic variants spanning the MMP10, MMP14, and MMP16 genes to detect association with dental caries experience in 13 age- and race-stratified (n = 3,587) samples from 6 parent studies. Analyses were performed separately for each sample, and results were combined across samples by meta-analysis. Two SNPs (rs2046315 and rs10429371) upstream of MMP16 were significantly associated with caries in an individual sample of white adults and via meta-analysis across 8 adult samples after gene-wise adjustment for multiple comparisons. Noteworthy is SNP rs2046315 (p = 8.14 × 10⁻⁸) association with caries in white adults. This SNP was originally nominated in a genome-wide-association study (GWAS) of dental caries in a sample of white adults and yielded associations in a subsequent GWAS of surface level caries in white adults as well. Therefore, in our study, we were able to recapture the association between rs2046315 and dental caries in white adults. Although we did not strengthen evidence that MMPs 10, 14, and 16 influence caries risk, MMP16 is still a likely candidate gene to pursue.

Interaction of spirochetes with the host fibrinolytic system and potential roles in pathogenesis

The pathogenic spirochetes Borrelia burgdorferi, B. hermsii, B. recurrentis, Treponema denticola and Leptospira spp. are the etiologic agents of Lyme disease, relapsing fever, periodontitis and leptospirosis, respectively. Lyme borreliosis is a multi-systemic disorder and the most prevalent tick-borne disease in the northern hemisphere. Tick-borne relapsing fever is persistent in endemic areas worldwide, representing a significant burden in some African regions. Periodontal disease, a chronic inflammatory disorder that often leads to tooth loss, is caused by several potential pathogens found in the oral cavity including T. denticola. Leptospirosis is considered the most widespread zoonosis, and the predominant human disease in tropical, undeveloped regions. What these diseases have in common is that they are a significant burden to healthcare costs in the absence of prophylactic measures. This review addresses the interaction of these spirochetes with the fibrinolytic system, plasminogen (Plg) binding to the surface of bacteria and the generation of plasmin (Pla) on their surface. The consequences on host-pathogen interactions when the spirochetes are endowed with this proteolytic activity are discussed on the basis of the results reported in the literature. Spirochetes equipped with Pla activity have been shown to degrade extracellular matrix (ECM) components, in addition to digesting fibrin, facilitating bacterial invasion and dissemination. Pla generation triggers the induction of matrix metalloproteases (MMPs) in a cascade of events that enhances the proteolytic capacity of the spirochetes. These activities in concert with the interference exerted by the Plg/Pla on the complement system - helping the bacteria to evade the immune system - should illuminate our understanding of the mechanisms involved in host infection.

Gingival crevicular fluid levels of Matrix Metalloproteinase-1 (MMP-1) and Tissue Inhibitor of Metalloproteinase-1 (TIMP-1) in periodontal health and disease

BACKGROUND

Matrix Metalloproteinases (MMPs) are directly responsible for pathogenesis of periodontal diseases and their activity is regulated by Tissue Inhibitor of Metalloproteinases (TIMPs). This study was aimed to evaluate changes in gingival crevicular fluid (GCF) levels of MMP-1 and TIMP-1 in periodontal health and disease.

MATERIALS AND METHOD

Clinical parameters were recorded and GCF samples were collected from 30 subjects with chronic generalised periodontitis and 20 periodontally healthy subjects. Subjects with periodontitis underwent scaling and root planing (SRP). GCF samples were collected and clinical parameters were recorded again after 1 month of SRP. GCF levels of MMP-1 and TIMP-1 were detected by ELISA.

RESULTS

GCF levels of MMP-1 were significantly increased in subjects with periodontitis at baseline (P0) as compared to periodontally healthy subjects (C). GCF levels of MMP-1 reduced significantly in subjects with periodontitis after treatment (P1) as compared to P0. GCF levels of TIMP-1 were significantly reduced in P0 as compared to C. GCF levels of TIMP-1 increased significantly in P1 as compared to P0.

CONCLUSION

Substantial elevation in GCF levels of MMP-1 and reduction in TIMP-1 were found in periodontitis as compared to healthy subjects. GCF levels of MMP-1 and TIMP-1 improved significantly after treatment.

Caries correlates strongly to salivary levels of matrix metalloproteinase-8

The caries process in dentin involves the degradation of both mineral and organic matrix. The demineralization has been demonstrated to be caused by bacterial acids. However, the collagen degradation is considered to be initiated by endogenous proteolytic enzymes, mainly collagenolytic matrix metalloproteinases (MMPs). This paper aims to relate salivary MMP-8 (or salivary collagenase-2) and tissue inhibitor of MMP (TIMP-1) levels to manifest caries in a large number of subjects. A random sample of 451 adults (aged 18-87 years) living in the south of Sweden was included in this study. Standard clinical examinations were performed, and stimulated saliva was collected and analyzed for concentrations of MMP-8, TIMP-1 and total protein, using an immunofluorometric assay, an enzyme-linked immunosorbent assay and the Bradford assay, respectively. Salivary numbers of mutans streptococci and lactobacilli were determined using a chair-side kit. Subjects with manifest caries lesions presented with elevated levels of MMP-8 (p < 0.001) as well as total protein, MMP-8/TIMP-1 ratio, bleeding on probing and plaque index (p = 0.05) compared with subjects without manifest caries. Multiple linear regression analysis with caries as the dependent variable revealed MMP-8 as the only significant explanatory variable (p < 0.001). TIMP-1 was not significant in any case. Using MMP-8 as the dependent variable revealed total protein concentration, caries lesions (p ≤ 0.001) and salivary secretion rate (p = 0.05) as explanatory variables. In conclusion, our data reveal that subjects with manifest caries lesions have elevated levels of salivary MMP-8 relative to subjects with no caries lesions.

Saliva and dental erosion

Dental erosion is a multifactorial condition. The consideration of chemical, biological and behavioral factors is fundamental for its prevention and therapy. Among the biological factors, saliva is one of the most important parameters in the protection against erosive wear.

OBJECTIVE

This review discusses the role of salivary factors on the development of dental erosion.

MATERIAL AND METHODS

A search was undertaken on MeDLINe website for papers from 1969 to 2010. The keywords used in the research were "saliva", "acquired pellicle", "salivary flow", "salivary buffering capacity" and "dental erosion". Inclusion of studies, data extraction and quality assessment were undertaken independently and in duplicate by two members of the review team. Disagreements were solved by discussion and consensus or by a third party.

RESULTS

Several characteristics and properties of saliva play an important role in dental erosion. Salivary clearance gradually eliminates the acids through swallowing and saliva presents buffering capacity causing neutralization and buffering of dietary acids. Salivary flow allows dilution of the acids. In addition, saliva is supersaturated with respect to tooth mineral, providing calcium, phosphate and fluoride necessary for remineralization after an erosive challenge. Furthermore, many proteins present in saliva and acquired pellicle play an important role in dental erosion.

CONCLUSIONS

Saliva is the most important biological factor affecting the progression of dental erosion. Knowledge of its components and properties involved in this protective role can drive the development of preventive measures targeting to enhance its known beneficial effects.

Estimation of matrix metalloproteinase-3 levels in gingival crevicular fluid in periodontal disease, health and after scaling and root planing

Background:

Initial research has shown a positive correlation between the severity of periodontal disease and matrix metalloproteinase-3 (MMP-3) concentrations in gingival crevicular fluid (GCF). However, there are no enough reports to correlate the MMP-3 concentrations in GCF in periodontal health, disease and after treatment. Hence, the present study is to estimate the levels of MMP-3 in GCF in periodontal health, disease and to evaluate the effect of periodontal therapy on MMP-3 concentrations in GCF.

Materials and Methods:

Periodontal examination and collection of GCF by extracrevicular method was performed in 30 subjects selected randomly and categorized into three groups. Group I (Healthy, n=10), group II (Chronic periodontitis, n=20) and group III (After treatment group, n=20). Scaling and root planing (SRP) was performed and GCF was collected after 8 weeks of treatment. MMP-3 levels were estimated in GCF samples using enzyme linked immunosorbent assay (ELISA).

Results:

MMP-3 was detected in all samples. Highest mean MMP-3 concentrations in GCF were obtained for group II (7.490 ng/ml), while the lowest concentrations were seen in group I (0.344 ng/ml) and group III (2.129 ng/ml). This suggests that MMP-3 levels in GCF increases proportionally with the progression of periodontal disease and decreases after treatment.

Conclusion:

There is a substantial increase in the concentrations of MMP-3 as periodontal disease progresses. Since MMP-3 levels in GCF are positively correlated with gingival index, probing pocket depth and clinical attachment level, MMP-3 may be considered as a “novel biomarker” in periodontal disease progression. However, controlled, longitudinal studies are needed to confirm this possibility.

Oral inflammatory diseases and systemic inflammation: role of the macrophage

Inflammation is a complex reaction to injurious agents and includes vascular responses, migration, and activation of leukocytes. Inflammation starts with an acute reaction, which evolves into a chronic phase if allowed to persist unresolved. Acute inflammation is a rapid process characterized by fluid exudation and emigration of leukocytes, primarily neutrophils, whereas chronic inflammation extends over a longer time and is associated with lymphocyte and macrophage infiltration, blood vessel proliferation, and fibrosis. Inflammation is terminated when the invader is eliminated, and the secreted mediators are removed; however, many factors modify the course and morphologic appearance as well as the termination pattern and duration of inflammation. Chronic inflammatory illnesses such as diabetes, arthritis, and heart disease are now seen as problems that might have an impact on the periodontium. Reciprocal effects of periodontal diseases are potential factors modifying severity in the progression of systemic inflammatory diseases. Macrophages are key cells for the inflammatory processes as regulators directing inflammation to chronic pathological changes or resolution with no damage or scar tissue formation. As such, macrophages are involved in a remarkably diverse array of homeostatic processes of vital importance to the host. In addition to their critical role in immunity, macrophages are also widely recognized as ubiquitous mediators of cellular turnover and maintenance of extracellular matrix homeostasis. In this review, our objective is to identify macrophage-mediated events central to the inflammatory basis of chronic diseases, with an emphasis on how control of macrophage function can be used to prevent or treat harmful outcomes linked to uncontrolled inflammation.

Formulation and evaluation of PLA and PLGA in situ implants containing secnidazole and/or doxycycline for treatment of periodontitis

The purpose of this study is to formulate in situ implants containing doxycycline hydrochloride and/or secnidazole that could be used in the treatment of periodontitis by direct periodontal intrapocket administration. Biodegradable polymers [poly (lactide) (PLA) and poly (lactide-co-glycolide) (PLGA)], each polymer in two concentrations 25%w/w, 35%w/w were used to formulate the in situ implants. The rheological behavior, in vitro drug release and the antimicrobial activity of the prepared implants were evaluated. Increasing the concentration of each polymer increases the viscosity and decreases the percent of the drugs released after 24 h. PLA implants showed a slower drugs release rate than PLGA implants in which the implants composed of 25% PLGA showed the fastest drugs release. The in vitro drug release and antimicrobial activity results were compared with results of Atridox. Results revealed that the pharmaceutical formulation based on 25% PLGA containing secnidazole and doxycycline hydrochloride has promising activity in treating periodontitis in comparison with Atridox.

Proteolytic Activities of Oral Bacteria on ProMMP-9 and the Effect of Synthetic Proteinase Inhibitors

Tissue reactions to bacteria lead to proinflammatory reactions involving matrix metalloproteinases (MMPs). Synthetic protease inhibitors may offer new possibilities to regulate bacterial proteases. We investigated proteolytic activities of certain periodontal bacteria, their effects on the latent proMMP-9, and the effects of synthetic MMP inhibitors and a serine protease inhibitor Pefabloc. The strains studied were Porphyromonas gingivalis, Prevotella intermedia, Peptostreptoccus micros, Prevotella nigrescens, Fusobacterium nucleatum, and 5 Aggregatibacter actinomycetemcomitans serotypes. Their gelatinolytic activities and the effects of certain synthetic MMP inhibitors and Pefabloc were analyzed by zymography. Bacterial effects on proMMP-9 conversion were investigated by Western immunoblot. All investigated periodontal bacteria produced gelatinolytic cell-bound and extracellular proteinases which could fragment latent proMMP-9, suggesting co-operative processing cascades in oral tissue remodeling. A. actinomycetemcomitans produced the weakest gelatinolytic activity. Synthetic proteinase inhibitors exhibited slight but clear reductive effects on the bacterial proteolytic activities. We conclude that targeted anti-proteolytic treatment modalities against bacterial-host proteolytic cascades can be developed.

Levels of matrix metalloproteinases-8 and -9 with simultaneous presence of periodontal pathogens in gingival crevicular fluid as well as matrix metalloproteinase-9 and cholesterol in blood

BACKGROUND AND OBJECTIVES

To investigate the levels of matrix metalloproteinase (MMP) -8 and -9 with the simultaneous presence of periodontal pathogens in gingival crevicular fluid (GCF) as well as MMP-9 and cholesterol in blood. Although bacterial pathogens are required to initiate the periodontal disease process, in some individuals the reaction to bacteria may lead to an excessive host response, resulting in a general inflammatory response.

METHODS

MMP-9 and lipids were analyzed from the blood samples of 33 subjects with a 16-year history and oral health records of periodontal disease as well as from 31 periodontally healthy controls. Information was obtained on education, body mass index, and family history of atherosclerosis. GCF was taken to determine MMP-8 and MMP-9 levels, and bacterial samples were simultaneously collected for polymerase chain reaction assessment of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Tannerella forsythia, and Treponema denticola. Analysis of variance, chi-squared test, and multiple logistic regression analysis were used to analyze the results.

RESULTS

Demographic data showed significant differences between patients and controls in smoking (P < 0.01), body mass index (P < 0.05), family history of atherosclerotic disease (P < 0.01), and education (P < 0.01). Significant differences were also observed in oral health data, in the detection of P. gingivalis (P < 0.001), P. intermedia (P < 0.01), P. nigrescens (P < 0.001), and T. forsythia (P < 0.001) and in the levels of MMP-8 and MMP-9 in GCF between patients and controls. T. forsythia[odds ratio(OR) 10.1; P = 0.001] and age (OR 5.54; P = 0.008) appeared to be the main independent predictors for high MMP-8 in GCF. Patients had significantly higher total cholesterol (P < 0.01), low-density lipoprotein cholesterol (P = 0.05), and triglycerides (P < = 0.01) than controls. Plasma levels of MMP-9 were significantly higher in patients than in controls (P = 0.001).

CONCLUSIONS

Specific periodontal microorganisms appeared to induce host response, with increased release of MMP-8 and MMP-9 in gingival pockets as well as of MMP-9 in plasma, possibly triggering its up-regulation in blood.

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.

Effects of phase I periodontal treatment on gingival crevicular fluid levels of matrix metalloproteinase-3 and tissue inhibitor of metalloproteinase-1

OBJECTIVES

The aim of this study was to evaluate the effects of phase I periodontal treatment on gingival crevicular fluid (GCF) levels of matrix metalloproteinase (MMP)-3 and tissue inhibitors of metalloproteinase (TIMP)-1.

METHODS

Plaque index, gingival index, pocket depth and clinical attachment loss were recorded and GCF samples were collected from 20 chronic periodontitis (CP) patients and 20 periodontally healthy controls (C) before treatment. CP patients received phase I periodontal treatment and all clinical parameters were recorded and GCF samples were collected once more after treatment. Assays were performed by an enzyme-linked immunosorbent assay.

RESULTS

All of the clinical parameters improved significantly after the therapy (p<0.05). Baseline GCF levels of MMP-3 were significantly higher than C and that level was reduced significantly by treatment compared with baseline levels (p<0.05). Baseline GCF levels of TIMP-1 were lower than post-treatment levels and C (p<0.05). GCF levels of TIMP-1 increased significantly by treatment compared with baseline levels (p<0.05).

CONCLUSION

This study shows that the clinical improvements after phase I periodontal therapy are accompanied by reduction in MMP-3 and increasing in TIMP-1 GCF levels.

Evaluation of the Inhibitory Effect of Triphala on PMN-Type Matrix Metalloproteinase (MMP-9)

BACKGROUND

This study evaluated the inhibitory activity of triphala on PMN-type matrix metalloproteinase (MMP-9) expressed in adult periodontitis patients and compared its activity with another ayurvedic drug, kamillosan, and doxycycline, which has known inhibitory activity.

METHODS

Matrix metalloproteinases (MMPs) were extracted from gingival tissue samples from 10 patients (six males, four females) with chronic periodontitis. Tissue extracts were treated with the drug solutions, the inhibition was analyzed by gelatin zymography, and the percentage of inhibition was determined by a gel documentation system.

RESULTS

The activity of MMPs was significantly decreased with the use of the drugs. Triphala showed a 76.6% reduction of MMP-9 activity, whereas kamillosan showed a 46.36% reduction at a concentration of 1,500 microg/ml (crude extract) and doxycycline showed a 58.7% reduction at a concentration of 300 microg/ml (pure drug).

CONCLUSION

The present study showed the strong inhibitory activity of triphala on PMN-type MMPs involved in the extracellular matrix (ECM) degradation during periodontitis.

Matrix metalloproteinases (MMPs) in oral diseases

Matrix metalloproteinases (MMPs) are a group of enzymes that in concert are responsible for the degradation of most extracellular matrix proteins during organogenesis, growth and normal tissue turnover. The expression and activity of MMPs in adult tissues is normally quite low, but increases significantly in various pathological conditions that may lead into unwanted tissue destruction, such as inflammatory diseases, tumour growth and metastasis. MMPs have a marked role also in tissue destructive oral diseases. The role of collagenases, especially MMP-8, in periodontitis and peri-implantitis is the best-known example of the unwanted tissue destruction related to increased presence and activity of MMPs at the site of disease, but evidence has been brought forward to indicate that MMPs may be involved also in other oral diseases, such as dental caries and oral cancer. This brief review describes some of the history, the current status and the future aspects of the work mainly of our research groups looking at the presence and activity of various MMPs in different oral diseases, as well as some of the MMP-related aspects that may facilitate the development of new means of diagnosis and treatment of oral diseases.

Activation of human matrix metalloproteinase 2 by gingival crevicular fluid and Porphyromonas gingivalis

AIM

To assess the potential of gingival crevicular fluid (GCF) from adult periodontitis patients and Porphyromonas gingivalis proteases to activate matrix metalloproteinase 2 (MMP-2) in vitro.

MATERIAL AND METHODS

GCF samples were collected from each of 15 adult periodontitis patients, from a clinically healthy site, a deep (>6 mm) bleeding site, and a deep nonbleeding site. The GCF samples were examined for general proteolytic activity, gelatinolytic activity and ability to activate pro-MMP-2 by zymography. Ultrasonic extracts of a range of clinical isolates of P. gingivalis cells and purified arg- and lys-gingipains were also assessed for their ability to activate pro-MMP-2.

RESULTS

GCF from deep nonbleeding sites showed higher general proteolytic activity than samples from deep bleeding and healthy sites but this did not reach statistical significance. Pefabloc, a general serine protease inhibitor, inhibited the majority (92%) of the proteolytic activity. GCF samples contained neutrophil MMP-9 in its latent form in 93% of the samples, and in its activated form in 40% of the samples. In contrast, MMP-2 was present in only trace amounts in 9% of the samples. When latent MMP-2 was added to these GCF samples, it was converted to the activated form (59 kDa) in 68% of the samples. Lower molecular weight (55 and 45 kDa) activated forms also appeared in 53% of the samples, particularly those from deep sites. Activation to the 55 and 45 kDa forms was inhibited by MSAAPket (a neutrophil elastase inhibitor), whereas Pefabloc completely inhibited the activation of latent MMP-2. All ultrasonic extracts of P. gingivalis activated latent MMP-2 in a concentration- and time-dependent manner. Also, latent MMP-2 was activated by purified arg-gingipain but less efficiently by lys-gingipain.

CONCLUSION

These findings suggest that P. gingivalis arg-gingipain and neutrophil elastase present in GCF can activate latent MMP-2, which may contribute in vivo to local periodontal tissue destruction.

Laminin-5 gamma2-chain and collagenase-2 (MMP-8) in human peri-implant sulcular fluid

Laminin-5 (LN-5) is an important epithelial cell-derived structural and adhesive component in hemidesmosomes and basement membranes (BM). In peri-implant tissue, gingival BM underlies the junctional epithelium (JE) and reflects the peri-implant health. Matrix metalloproteinase-8 (MMP-8 or collagenase-2) is one of the key mediators of periodontal tissue destruction. Western immunoblotting with image analysis was used to quantitate the molecular forms of LN-5 gamma2-chain and MMP-8 in peri-implant sulcular fluid (PISF) from healthy and diseased implants. These observations were related to the recorded gingival (GI) and bone resorption (BR) indices of the studied sites. Altogether, 72 PISF samples from osseointegrated dental implants were examined. Significantly elevated levels of fragmented LN-5 gamma2-chain species (45 and 70 kDa) and MMP-8 immunoreactivities were observed in diseased PISF in relation to healthy PISF. The elevated levels of both LN-5 gamma2-chain 45 and 70 kDa fragments and MMP-8 in diseased PISF from peri-mucositis (BR = 0) and peri-implantitis (BR >/= 1) lesions strongly correlated with elevated GI. Low levels - almost comparable to those seen in healthy control PISF - were seen in PISF from peri-implantitis lesions (BR >/= 1) with no GI. Activation of 75 kDa neutrophil (PMN)-type proMMP-8 to 10 kDa lower-molecular-size active forms was especially detected in PISF from peri-implantitis with elevated GI. These cross-sectional findings indicate that elevated MMP-8 and LN-5 gamma2-chain fragment levels in PISF can reflect the active phase of the inflammatory peri-implant disease. Longitudinal studies are required to assess their use, either alone or in combination as molecular biochemical PISF markers, to predict the risk of progression of peri-implantitis, as well as to monitor the impact of treatment of the disease.

The relationship between MMPs and pH in whole saliva of radiated head and neck cancer patients

BACKGROUND

Radiation therapy for head and neck tumour patients may lead to decreased salivary flow, oral mucosal lesions and increased caries experience. Salivary matrix metalloproteinases (MMPs) may participate in the pathogenesis of mucosal lesions and dentinal caries. The aims of this study were: (i) to assay the presence, molecular forms and proteolytic activity of MMP-8 (collagenase-2) and MMP-9 (gelatinase B) in the whole saliva of head and neck cancer patients having radiation therapy; (ii) to see whether salivary pH affects the activity of MMP-8 and MMP-9; and (iii) to find out the possible connection between MMP-8 and MMP-9 with the eruption of oral mucosal lesions during radiation therapy.

METHODS

The whole saliva samples of 39 head and neck cancer patients having radiation therapy were collected before, during and after radiation therapy, and saliva flow rate, pH, buffer capacity, Streptococcus mutans, Lactobacillus and Candida albicans were measured. Any oral mucosal lesions were examined during each visit. The levels of MMP-8 were measured by immunofluorometric assay (IFMA) and the presence of different MMP-8 forms was analysed using Western immunoblotting. The presence and molecular forms of MMP-9 were analyzed by gelatin zymography. MMP-9 capture activity assay was used to determine the APMA-activated MMP-9 activity (total) and the endogenously active MMP-9 (free activity).

RESULTS

Salivary flow rate, buffer capacity and pH decreased, and the levels of Lactobacilli increased significantly, during the first half of the radiation therapy. The endogenously activated salivary MMP-9 correlated with low salivary pH (P = 0.013). No connection was found between the oral mucosal lesions and salivary MMP-8 or MMP-9.

CONCLUSIONS

In this study, salivary MMP-8 or MMP-9 did not correlate with the presence of radiation induced oral mucosal lesions, but the activation of MMP-9 may be dependent on pH.

Effects of phase I periodontal treatment on gingival crevicular fluid levels of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1

BACKGROUND

Matrix metalloproteinase-1 (MMP-1) is a member of a family of enzymes which are capable of degrading most extracellular matrix macromolecules. Extracellular control of MMPs is exerted by tissue inhibitors of metalloproteinases (TIMP) and by mechanisms of pro-MMP activation. Levels of MMPs and TIMPs change during healing, inflammation, and normal tissue turnover. The aim of this study was to evaluate the effects of phase I periodontal treatment on gingival crevicular fluid (GCF) levels of MMP-1 and TIMP-1.

METHODS

Ten patients with chronic periodontitis who had sites with probing depths > or = 4 mm and 10 periodontally healthy persons (controls) were included in this study. Clinical measurements including plaque (PI) and gingival (GI) indexes, probing depths (PD), and clinical attachment loss (CAL) were recorded both at baseline (before treatment, BT) and after phase I periodontal treatment (AT). Assays for MMP-1 and TIMP-1 were performed by an enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

All of the clinical conditions significantly improved and GCF volume decreased AT (P<0.05). Levels of MMP-1 were higher in patients BT than in controls (C) (P<0.05). Levels of MMP-1 were reduced AT compared to BT (P<0.05). In addition, TIMP-1 levels were lower at BT than AT and in C (P<0.05). Statistically significant differences were found between levels of TIMP-1 at BT and AT (P<0.05). The ratio of MMP-1 to TIMP-1 was significantly lower in C than patients at BT; this ratio was also significantly lower at AT than BT (P<0.05).

CONCLUSIONS

These results suggest that levels of MMP-1 in GCF decreased and total levels of TIMP-1 in GCF increased after phase I periodontal therapy. The ratio of MMP-1 to TIMP-1 changed after phase I periodontal therapy, becoming close to that of the controls.

Collagenase-2 (MMP-8) and collagenase-3 (MMP-13) in adult periodontitis: molecular forms and levels in gingival crevicular fluid and immunolocalisation in gingival tissue

AIM

To determine the cellular and molecular forms of MMP-8 (collagenase-2) and MMP-13 (collagenase-3) associated with chronic adult periodontitis by examining the species present in gingival crevicular fluid (GCF) and enzyme distribution in gingival tissue.

METHODS

30-s GCF samples were collected directly from the periodontal pockets of 12 untreated patients using filter paper strips. After elution into buffer, the samples were examined by Western immunoblotting with polyclonal antibodies for MMP-8 and MMP-13 and quantification by scanning image analysis. Individual band intensities were expressed as a percentage of total sample absorbance and mean patient values were calculated. Gingival tissue from 6 patients was fixed in formalin and embedded in paraffin wax. MMP-8 and MMP-13 were localised using the same antibodies and an avidin-biotin-peroxidase detecting system. Double staining was performed with a contrasting substrate reaction.

RESULTS

The majority of MMP-8 staining in pre-treatment GCF was present in 80, 75 and 60 kD bands corresponding to prepro-, pro- and active forms of PMN-type enzyme. 43 and 38 kD bands evidently represented active, fibroblast-type MMP-8. Immunoreactivities at >100 kD and < or =30 kD were probably enzyme-inhibitor complex and degraded fragments, respectively. MMP-13 was seen mainly as 60 kD proenzyme with some 40 kD active enzyme and a small proportion of >100 kD complex. The percentages of MMP-8 PMN-type enzyme and MMP-13 proenzyme bands correlated significantly with gingival and bleeding indices (p<0.05). Immunohistochemistry demonstrated MMP-8 in PMNs, sulcular epithelial and also plasma cells in inflamed gingival connective tissue. MMP-13 immunoreactivity was detected in the sulcular epithelium and in macrophage-like cells.

CONCLUSION

Multiple species and elevated levels of both MMP-8 and MMP-13 from many rather than single cellular sources in the diseased periodontium are identified in untreated periodontitis GCF and active forms contribute to GCF collagenase activity.

Inhibition of proteolytic, serpinolytic, and progelatinase-b activation activities of periodontopathogens by doxycycline and the non-antimicrobial chemically modified tetracycline derivatives

BACKGROUND

Tetracyclines, particularly doxycycline (Doxy), and their non-antimicrobial chemically-modified derivatives (CMTs) inhibit the activities of human matrix metalloproteinases (MMPs), and reduce the severity and progression of periodontal disease in animal models and humans. In this study, the effects of Doxy and CMT-1, -3, and -5 on proteolytic, serpinolytic, and progelatinase-B activation activities of potent periodontopathogens were studied.

METHODS

The effect of Doxy and CMTs (0.5 to 50 microM) on proteolytic activities were investigated by incubating bacteria with chromogenic substrates or human serum albumin. A collagenolytic fraction of Porphyromonas gingivalis was used to evaluate the effect of these substances on collagenolytic (type I collagen) and serpinolytic (alpha1-proteinase inhibitor) activities. Lastly, the effect of Doxy on progelatinase-B (pro-MMP-9) activation by purified proteinases from P. gingivalis and Treponema denticola was investigated by SDS-PAGE/Western immunoblotting.

RESULTS

Doxy and CMTs, except CMT-5 which lacks the structural elements required for cation chelation, inhibited Arg- and Lys-gingipain activities as well as collagenolytic activity of P. gingivalis. Doxy and CMTs did not markedly affect the chymotrypsin-like activity of T. denticola but inhibited its trypsin-like activity. In addition, degradation of human serum albumin by cells of P. gingivalis and T. denticola was strongly inhibited by Doxy and CMT-1. Doxy and CMT-1 also inhibited the inactivation of alpha1-proteinase inhibitor (serpinolytic activity) by a collagenolytic fraction of P. gingivalis. Lastly, Doxy prevented the latent to active conversion of human neutrophil progelatinase-B (pro-MMP-9) by Arg-gingipains A/B of P. gingivalis but not by the chymotrypsin-like proteinase of T. denticola.

CONCLUSIONS

Data from this study suggest that Doxy and CMTs have the potential to inhibit the periodontopathogenic bacterial proteinases, which contribute to tissue destruction cascades during periodontitis directly and indirectly by triggering the host response.

Long-term treatment with subantimicrobial dose doxycycline exerts no antibacterial effect on the subgingival microflora associated with adult periodontitis

BACKGROUND

The purpose of this study was to determine whether treatment with subantimicrobial dose doxycycline (SDD), 20 mg bid, exerted an antimicrobial effect on the microflora associated with adult periodontitis.

METHODS

Following the approval of the protocol and informed consent forms by the respective IRBs at the University of Florida and West Virginia University, 76 subjects with adult periodontitis were entered and randomly assigned to receive SDD or placebo. A split-mouth design was utilized, with each subject receiving subgingival scaling and root planing (SRP) in two quadrants immediately following baseline data collection, while the remaining two quadrants were left unscaled (non-SRP). Microbial samples were collected prior to treatment, after 3, 6, and 9 months of treatment, and after 3 months of no treatment. The samples were examined by microscopy and by enumeration on selective and non-selective media.

RESULTS

All treatments resulted in statistically significant decreases in the proportions of spirochetes and motile rods (P <0.05) and in an increase in the proportion of coccoid forms (P <0.0001) relative to baseline. No between-treatment differences were detected between the SDD and placebo treatments in either the SRP or non-SRP design, with the exception of the small and large spirochetal groups. The spirochetal proportions present in the SDD group were significantly lower (P<0.05) than the paired placebo group during the 9-month treatment and was preceded by a significant decrease (P<0.01) in the proportion of microbiologic sample sites that bled on probing. No between- treatment differences were detected in any of the other microbial parameters.

CONCLUSION

The microbial differences observed were attributed to the anticollagenase and anti-inflammatory properties of SDD and not to an antimicrobial effect.

The expression of MMP-8 in human odontoblasts and dental pulp cells is down-regulated by TGF-beta1

Recent findings show that matrix metalloproteinase-8 (MMP-8) is expressed, in addition to neutrophils, by human chondrocytes, cultured fibroblasts, and endothelial cells. We investigated the expression of MMP-8 in other human mesenchyme-derived cells, odontoblasts, and pulp tissue. Odontoblasts and pulp tissue were collected from extracted human teeth for MMP-8 mRNA analysis with reverse-transcription/polymerase chain-reaction (RT-PCR) and Southern blot. The expression, localization, and secretion of MMP-8 protein were studied with Western blot, immunohistochemistry, and immunofluorometric assay. The effect of TGF-beta1 (10 ng/mL) on the expression, secretion, and concentration of secreted MMP-8 was studied by odontoblast and pulp tissue culture methods (Tjäderhane et al., 1998a). RT-PCR demonstrated MMP-8 mRNA expression in native and cultured odontoblasts and pulp tissue and cultured pulp fibroblasts, with a 522-bp transcript comparable with that of bone marrow cells. The specificity of PCR was confirmed with Southern blot. Western blot with MMP-8-specific antibody detected 65- and 50-kDa proteins in native samples, representing latent and active forms of mesenchymal-type MMP-8, and in the conditioned odontoblast culture media, 50-kDa protein was observed. TGF-beta down-regulated the MMP-8 mRNA and concentration of secreted protein in both cultures. Immunohistochemical staining detected MMP-8 in odontoblasts. These findings indicate that mesenchyme-derived cells of the dentin-pulp complex express, synthesize, and activate MMP-8, which may, in concert with odontoblast-derived gelatinases, participate in organization of dentin organic matrix prior to mineralization.

Activation of neutrophil collagenase in periodontitis

Neutrophil collagenase (matrix metalloproteinase 8 [MMP-8]) is an important mediator of tissue destruction in inflammatory diseases. Studies of anaerobic periodontal infections have shown that active MMP-8 in gingival crevicular fluid is associated with the degradation of periodontal tissues in progressive periodontitis whereas the latent enzyme is predominant in gingivitis. Since the activation of MMP-8 appears to be a crucial step in periodontitis, we have examined the activation of MMP-8 in gingival crevicular fluid samples by using a soluble biotinylated collagen substrate. Analysis of gingival crevicular fluid in periodontitis, gingivitis, and controls revealed sixfold (P < 0.001)-higher levels of active collagenase in periodontitis (n = 12) samples compared to gingivitis (n = 17) samples, which exhibited low levels of activity, while controls (n = 25) showed no activity. After gingival crevicular fluid was collected, no further activation of latent collagenase occurred in vitro. Although both MMP-1 and MMP-8, but not MMP-13, could be detected by immunoblots, blocking antibodies to MMP-1 showed that collagenase activity was largely contributed by MMP-8, which was localized to the matrix of diseased tissues. The MMP-8 in gingival crevicular fluid migrated primarily as a 60-kDa form with smaller amounts of a 78-kDa species, whereas MMP-8 isolated from peripheral neutrophils migrated at 70 and 89 kDa, corresponding to active and latent forms of the enzyme, respectively. Most of the MMP-8 in the 60- and 70-kDa bands selectively bound to tissue inhibitor of metalloproteinase 2 and collagen, indicating that most, but not all, of the enzyme in these bands was in an activated form. However, the amounts of the 78- and 60-kDa forms from gingival crevicular fluid in different samples did not correlate (r2 = 0.028) with the latent and active enzyme measured by collagenase assay. Collectively, these studies have identified distinct forms of latent and active MMP-8 in gingival crevicular fluid that appear to result from a unique activation mechanism that occurs in periodontitis. The complexity of MMP-8 activation is further indicated by the presence of latent, activated, and superactivated forms of MMP-8 in the 60- and 70-kDa bands obtained from gingival crevicular fluid and neutrophil samples, respectively.

Inhibition of the activities of matrix metalloproteinases 2, 8, and 9 by chlorhexidine

Matrix metalloproteinases (MMPs) are a host cell-derived proteolytic enzyme family which plays a major role in tissue-destructive inflammatory diseases such as periodontitis. The aim of the present study was to evaluate the inhibitory effect of chlorhexidine (CHX) on MMP-2 (gelatinase A), MMP-9 (gelatinase B), and MMP-8 (collagenase 2) activity. Heat-denatured type I collagen (gelatin) was incubated with pure human MMP-2 or -9 activated with p-aminophenylmercuric acetate (APMA), and the proteolytic degradation of gelatin was monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Coomassie blue staining. The effect of CHX on MMP-8 activity was also studied with a cellular model addressing the ability of phorbol myristate acetate (PMA)-triggered human peripheral blood neutrophils (polymorphonuclear leukocytes [PMNs]) to degrade native type I collagen. CHX inhibited the activities of both gelatinases (A and B), but MMP-2 appeared to be more sensitive than MMP-9. Adding calcium chloride to the assay mixtures almost completely prevented the inhibition of MMP-9 activity by CHX, while the inhibition of MMP-2 activity could be reversed only when CHX was used at a low concentration. This observation suggests that CHX may act via a cation-chelating mechanism. CHX dose-dependently inhibited collagenolytic activity of MMP-8 released by PMA-triggered PMNs. MMP-8 without APMA activation was inhibited clearly more efficiently than APMA-activated MMP-8. Our study suggests that the direct inhibition of the MMPs' activities by CHX may represent a new valuable effect of this antimicrobial agent and explains, at least in part, the beneficial effects of CHX in the treatment of periodontitis.

Tissue inhibitors of metalloproteinases level and collagenase activity in gingival crevicular fluid: the relevance to periodontal diseases

OBJECTIVES

To provide an overall assessment of levels of tissue inhibitors of metalloproteinases (TIMPs), collagenase activities, and of immuno-reactivities for matrix metalloproteinases (MMP)-1 and -8 in gingival crevicular fluid (GCF) obtained from healthy subjects, and gingivitis and periodontitis patients, and to analyse the relationships between periodontal tissue destruction and the GCF components in periodontal diseases by principal component analysis.

MATERIALS AND METHODS

GCF was sampled with sterile paper strips from 10 gingivitis and 11 periodontitis patients. Ten volunteers served as clinically healthy controls. TIMP-1 and -2 protein amounts in GCF were measured by ELISA, and active and APMA-activatable collagenase activities were determined by functional assays using image-analysis after SDS-PAGE.

RESULTS

GCF TIMP-1 level and both active and latent collagenase activities were significantly higher in the diseased groups than in the healthy group. TIMP-2 was detectable in only 29% of all subjects (mean: 2.06 ng). Western blot analysis showed that MMP-8 was the major interstitial collagenase in the GCF of the diseased groups. Principal component analysis using clinical parameters and the GCF components has indicated components one to three account for 87% of total variation when evaluating the relevance of their measurements to periodontal diseases.

CONCLUSIONS

We conducted the functional and immunological characterization of MMPs and TIMPs in the GCF of periodontally diseased patients. Principal component analysis indicated components one to three explaining 87% of total variation, and further suggested that higher collagenase activity (especially in active collagenase) would be an important marker in evaluating the pathogenesis of periodontitis. Consequently, these observations may have significant therapeutic and diagnostic implications.

The activation and function of host matrix metalloproteinases in dentin matrix breakdown in caries lesions

Matrix metalloproteinases (MMPs) are a family of enzymes which, in concert, are capable of degrading collagen. We investigated whether human MMPs could participate in the degradation of dentin organic matrix after demineralization. We performed Western blot analyses using MMP-specific antibodies to identify MMPs in human dental caries lesions. Enzymography and functional activity assays, with 125I-labeled gelatin as substrate or quantitating the degradation of type I collagen, were used to determine the activity of purified and salivary gelatinolytic (MMP-2 and MMP-9) and collagenolytic (MMP-8) enzymes with and without acid-activation in pHs relevant to caries. Respective analyses were done with caries-related bacteria. We performed electron microscope analyses to assess the degradative activity of sterilized salivary host MMPs on demineralized human dentin. Human MMP-2, MMP-8, and MMP-9 were identified in demineralized dentinal lesions. The latent purified forms of these enzymes were activated at low pH (4.5), followed by neutralization, mimicking the conditions during caries progression. Incubation of human saliva at low pH followed by neutralization resulted in a four-fold increase in the gelatinolytic activity. No gelatinolytic or collagenolytic activity was observed in bacterial samples. The activated enzymes in saliva degraded demineralized dentin organic matrix in vitro. These results demonstrate the pH-dependent activation mechanism of MMPs, which may have a distinct role in different physiological and pathological conditions. They further demonstrate that host MMPs, activated by bacterial acids, have a crucial role in the destruction of dentin by caries.