Mechanisms of connective tissue matrix destruction in periodontitis

Diagnostic accuracy of salivary active matrix metalloproteinase (aMMP)-8 point-of-care test for detecting periodontitis in adults: A systematic review and meta-analysis

OBJECTIVE

To determine the accuracy of salivary active matrix metalloproteinase (aMMP)-8 point-of-care test (POCT) for detecting periodontitis in adults, through meta-analysis.

MATERIALS AND METHODS

Diagnostic studies evaluating the accuracy of salivary/oral rinse aMMP-8 POCT for detecting periodontitis in adults, when compared with clinical examination, were considered eligible. A comprehensive search was performed up to 31 August 2023 through five databases. Quality Assessment of Diagnostic Accuracy Studies 2 was utilized to evaluate the methodological quality of the included articles. Meta-analysis was performed using Bayesian bivariate hierarchical model and subgroup analysis.

RESULTS

From 368 screened studies, 6 studies (4 cross-sectional and 2 longitudinal studies) were included in the meta-analysis. Overall, the pooled sensitivity and specificity of salivary aMMP-8-POCT for detecting periodontitis were 0.63 (95% CI: 0.41-0.82) and 0.84 (95% CI: 0.65-0.95), respectively. Subgroup analyses revealed that the 95% CI for oral fluid types, predefined diagnostic thresholds and the POCT systems largely overlapped, indicating that the differences between them may not be significant.

CONCLUSION

Salivary aMMP-8 POCT shows fair accuracy for detecting periodontitis. The diagnostic accuracy cannot be significantly influenced by the types of oral fluids, predefined diagnostic thresholds or the specific POCT systems used. More research is needed to confirm the clinical utility and implementation of aMMP-8 POCT in the diagnosis of periodontitis.

Matrix Metalloproteinases in the Periodontium-Vital in Tissue Turnover and Unfortunate in Periodontitis

The extracellular matrix (ECM) is a complex non-cellular three-dimensional macromolecular network present within all tissues and organs, forming the foundation on which cells sit, and composed of proteins (such as collagen), glycosaminoglycans, proteoglycans, minerals, and water. The ECM provides a fundamental framework for the cellular constituents of tissue and biochemical support to surrounding cells. The ECM is a highly dynamic structure that is constantly being remodeled. Matrix metalloproteinases (MMPs) are among the most important proteolytic enzymes of the ECM and are capable of degrading all ECM molecules. MMPs play a relevant role in physiological as well as pathological processes; MMPs participate in embryogenesis, morphogenesis, wound healing, and tissue remodeling, and therefore, their impaired activity may result in several problems. MMP activity is also associated with chronic inflammation, tissue breakdown, fibrosis, and cancer invasion and metastasis. The periodontium is a unique anatomical site, composed of a variety of connective tissues, created by the ECM. During periodontitis, a chronic inflammation affecting the periodontium, increased presence and activity of MMPs is observed, resulting in irreversible losses of periodontal tissues. MMP expression and activity may be controlled in various ways, one of which is the inhibition of their activity by an endogenous group of tissue inhibitors of metalloproteinases (TIMPs), as well as reversion-inducing cysteine-rich protein with Kazal motifs (RECK).

Salivary interleukin-1β as a biomarker to differentiate between periodontal health, gingivitis, and periodontitis

BACKGROUND

Periodontal diagnosis is based on recording clinical parameters including bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment loss (CAL). These techniques may be prone to errors due to different factors. Available biomarkers in the oral biofluid such as interleukin (IL)-1β could provide solutions for these issues. The study aimed to determine the potential of salivary IL-1β to differentiate periodontal health from disease and between gingivitis and periodontitis.

METHODS

Patients with gingivitis (N.=25), periodontitis (N.=50), and healthy periodontium (N.=25) were recruited for this study. For each patient, whole unstimulated saliva was collected followed by recording periodontal parameters namely; Plaque Index (PI), BOP, PPD, CAL. Level of salivary IL-1β was assayed by using enzyme-linked immunosorbent assays. Sensitivity and specificity of IL-1β, to differentiate any given condition, was determined by Receiver operating characteristic curve and area under the curve (AUC).

RESULTS

Both BOP and PI were significantly higher in association with gingivitis and periodontitis groups as compared to controls. Concentration of salivary IL-1β in periodontal health was significantly lower than gingivitis and periodontitis groups. The biochemical analyses showed that salivary IL-1β differentiated periodontal health from gingivitis (AUC 0.949) and periodontitis (AUC 0.852) but could not discriminate gingivitis from periodontitis (AUC 0.532). The proposed cut-off points to differentiate periodontal health from gingivitis was 103.8 pg/mL, while the value of the biomarker to differentiate periodontal health from periodontitis was 102.0 pg/mL.

CONCLUSIONS

Salivary IL-1β could be a reliable biomarker with a good level of accuracy to differentiate periodontal health from disease but not to discriminate gingivitis from periodontitis.

Role of various pharmacologic agents in alveolar bone regeneration: A review

Alveolar bone and gingiva are components of the periodontium that house the tooth. It constantly adapts itself to the masticatory forces and position of the tooth. However, localized diseases like chronic periodontitis and certain systemic diseases destroy periodontal tissues, which include the alveolar bone. Various pharmacological agents are being explored for their pleiotropic properties to combat the destruction of alveolar bone. This review focuses on the role of pharmacological agents in alveolar bone regeneration.

Reduction in Gingival Bleeding after Atelocollagen Injection in Patients with Hashimoto's Disease-A Pilot Study

Periodontal diseases are one of the main causes of tooth loss and the second most common oral disease after carries. Patients with autoimmune diseases, such as Hashimoto's disease, are more often vulnerable to infection. In the study group of patients, despite the lack of other signs of gingivitis, bleeding occurred after tooth brushing or minor trauma. Bleeding on probing is the first objective sign of ongoing inflammation. The study was conducted on a group of 17 patients diagnosed with Hashimoto's disease. The atelocollagen Linerase (100 mg) thinned with 5 mL 0.9% NaCl was used. A total of 0.05 mL of solution was injected into keratinized gingiva, two millimeters above the gingival papillae basement, four times in two-week intervals. The greatest decrease in the number of bleeding points was observed after the first and second injections of atelocollagen. After the third and fourth injections, the average BOP continued to decrease, but the decline was very slow. The use of atelocollagen made it possible to eliminate bleeding symptoms in the study group.

Effects of Saliva From Periodontally Healthy and Diseased Subjects on Barrier Function and the Inflammatory Response in in vitro Models of the Oral Epithelium

Background: Periodontitis is a multifactorial, bacteria-mediated chronic inflammatory disease that results in the progressive destruction of the tooth-supporting tissues. It is well-known that saliva from subjects suffering from this disease generally contains higher levels of pro-inflammatory mediators, matrix metalloproteinases (MMP), and bacteria-derived toxic products. The aim of this study was to investigate and compare the effects of saliva from periodontally healthy and diseased subjects on the barrier function and inflammatory response in in vitro models of the oral epithelium.

Methods: Unstimulated saliva samples from two groups of subjects, one with a healthy periodontium (n = 12) and one with severe generalized periodontitis (n = 11), were filter-sterilized. All the saliva samples were analyzed using an immunological multiplex assay to determine the levels of various cytokines and MMPs relevant to periodontitis. The impact of saliva on epithelial barrier integrity was assessed by monitoring transepithelial electrical resistance (TER) in an oral epithelium model using the B11 keratinocyte cell line. GMSM-K oral epithelial cells were treated with saliva from both groups to determine their ability to induce the secretion of interleukin-6 (IL-6) and interleukin-8 (IL-8), as determined by an enzyme-linked immunosorbent assay (ELISA).

Results: Saliva from the periodontitis subjects contained significantly higher concentrations of matrix metalloproteinase-8 (MMP-8), matrix metalloproteinase-9 (MMP-9), IL-8, and C-X-C motif chemokine ligand 1 (CXCL1) compared to saliva from the healthy subjects. Saliva from the healthy and periodontitis subjects affected cytokine secretion and TER in a similar manner. More specifically, saliva from both groups increased TER and induced IL-6 and IL-8 secretion in the in vitro oral epithelium models used.

Conclusion: Independently of the presence or absence of periodontitis, saliva can increase the relative TER and the secretion of IL-6 and IL-8 in in vitro models of the oral epithelium.

Association between hepatic and systemic inflammation and localized stage II/III periodontitis in young males: The CHIEF Oral Health study

AIM

To clarify the role of systemic inflammation in the associations between hepatic inflammation and localized periodontitis, which were conflicting among races.

MATERIALS AND METHODS

The study included 1112 military personnel (males), aged 18-40 years, in Taiwan. Localized periodontitis was classified into healthy/stage I (n = 796) and stage II/III (n = 316) according to the 2017 criteria. Systemic and hepatic inflammation were defined by the greatest tertiles of blood leukocyte counts (7.51 × 10³ /μl) and alanine aminotransferase (30 U/L), respectively. Multiple logistic regression analysis with adjustments for age, metabolic syndrome, betel nut consumption, and smoking were utilized to determine the associations.

RESULTS

There was a significant association between having a high systemic inflammation, whatever the hepatic inflammation severity, and the risk of having a localized stage II/III periodontitis (odds ratio [OR]: 1.62 [1.09-2.42] and 1.47 [1.00-2.15], respectively, for the presence of a high hepatic inflammation or not). However, no significant association was found among participants with low systemic inflammation, whatever the hepatic inflammation severity (OR: 1.31 [0.91-1.91]).

CONCLUSIONS

An association between hepatic inflammation and localized periodontitis in Taiwanese was observed only if systemic inflammation co-existed, possibly accounting for the racial difference in the association significantly reported in Japanese but not in non-Asian populations in prior studies.

The Potential Impact of Salivary IL-1 on the Diagnosis of Periodontal Disease: A Pilot Study

The aim of this study was to identify inflammatory cytokines as salivary biomarkers for periodontal disease. The subjects were 33 Korean adults aged 23 to 71 years. Using a multiplexed bead immunoassay called Luminex, the levels of inflammatory cytokines related to periodontal disease were evaluated. Oral examination for periodontal disease and gingival bleeding was conducted. With these two independent variables, differences in inflammatory cytokines were analyzed by an independent t-test and age-adjusted ANCOVA. Among the subjects, 21 had periodontal disease and 12 were healthy subjects. The gingival bleeding status was classified into low and high levels. Among 13 inflammatory cytokines in saliva, IL-1α, IL-1β, IL-4, IL-8, CCL2/MCP-1, CCL3/MIP-1α, and TNF-α were found to be significant biomarkers within the standard curve. The quantity of IL-1β was increased in subjects with high levels of gingival bleeding. IL-1α levels were increased in subjects with periodontal disease. After adjusting for age, the significant biomarkers for gingival bleeding and periodontal disease were IL-1β and IL-1α, respectively. Using the receiver operating characteristic (ROC) curve, IL-1β was confirmed as a significant biomarker. The sensitivity and specificity of IL-1β for predicting periodontitis were 88.24% and 62.5%, respectively. Therefore, IL-1 was found to be a significant biomarker for periodontal disease, and it could be used in the diagnosis of periodontal disease using saliva.

Dynamics of Matrix Metalloproteinase-1 and -8 Secretion in Gingival Crevicular Fluid after Gingival Recession Therapy via MCAT with Either Subepithelial Connective Tissue Graft or Collagen Matrix

OBJECTIVES

The objective of this study was to determine and estimate the changing levels of matrix metalloproteinases 1 and 8 (MMP-1 and MMP-8) in GCF at consecutive stages of healing after root coverage procedure via modified coronally advanced tunnel (MCAT) combined with either sub-epithelial connective tissue graft (SCTG) or collagen matrix (CM) and also to relate those changes to clinical outcomes of both therapeutic approaches.

MATERIALS AND METHODS

The study involved 20 patients with a total of 91 recessions. Those on one side of the mandible received MCAT plus CM while the contralateral ones MCAT plus SCTG. The evaluation of MMP-1 and MMP-8 concentrations in Gingival Crevicular Fluid (GCF) took place at baseline, then at 1, 2, and 4 weeks, and finally at 3 months after surgery. Elisa protocol was applied to determine the levels of MMP-1 and MMP-8 in GCF.

RESULTS

Three-month observation revealed statistically significant changes in MMP-1, MMP-8 and Sulcus Fluid Flow Rate (SFFR) values after implementation of both techniques. A correlation was found between a difference in MMP-1 concentrations and gain in Keratinized Tissue (KT) after SCTG and CM. MMP-8 levels and a Gingival Thickness (GT) gain observed after CM was also correlated.

CONCLUSIONS

A type of augmentative material does appear to determine the dynamics of MMP-1 secretion.

Intrapocket application of tea tree oil gel in the treatment of stage 2 periodontitis

Background

The gold standard in treatment of periodontitis is mechanical removing of dental biofilm but using local delivery drugs as adjunctive to SRP is widely used to modulate inflammatory host and eradicate microbes. Tea tree oil (TTO) has a broad-spectrum antimicrobial, anti-inflammatory, antifungal, antiviral, antioxidant effect. This study aimed to assess clinically and biochemically the effect of intrapocket application of TTO (Melaleuca alternifolia) gel adjunctive to scaling and root planing (SRP) in the treatment of stage 2 (moderate) periodontitis and to correlate the biochemical levels with clinical response.

Methods

A randomized, controlled clinical trial was conducted on thirty patients with stage 2 periodontitis. Patients were equally divided into two groups: Control Group treated with (SRP) alone and Test Group treated with SRP and locally delivered 5% TTO gel. Clinical assessment included pocket probing depth (PPD), clinical attachment loss (CAL), gingival index (GI) and bleeding on probing (BOP) measured at baseline and after 3 and 6 months. The level of matrix metalloproteinase-8 (MMP-8), in the gingival crevicular fluid (GCF) was also assessed at baseline and after1, 3 and 6 months by Enzyme-linked immunosorbent assay (ELISA) kit. Chi-square, Student t- tests, Mann–Whitney U test and Spearman correlation were the statistical tests used in the study.

Results

An improvement of all clinical and biochemical parameters was observed (at p < 0.001) in both groups. A significant difference between the two groups was found in both clinical and biochemical parameters.

Conclusion

The local delivery of TTO gel adjunctive to SRP proved to be effective in the treatment of stage II periodontitis.

Trial registration The study was retrospectively registered at clinicaltrials.gov NCT04769271, on 24/2/2021.

Comparisons of various anthropometric indexes with localized Stage II/III periodontitis in young adults: The CHIEF oral health study

BACKGROUND

A J-shaped relationship of body mass index (BMI) with severe periodontitis has been reported. However, it is unknown for other anthropometric indexes in young adults.

METHODS

A cross-sectional study examined the relationships in 325 military men and women, aged 20 to 45 years in Taiwan. Anthropometric indexes included BMI, waist circumference (WC), and waist-to-height ratio (WHtR). The severity of localized periodontitis was defined as healthy (n = 42), Stage I (initial) (n = 228), and Stage II/III (moderate/severe) (n = 55) according to the 2017 Periodontal Diseases Classification. Smooth curve fitting and multiple logistic regression analyses adjusting for age, sex, betel nut consumption, and smoking were used to determine the threshold effect between various anthropometric and the risk of localized Stage II/III periodontitis.

RESULTS

In the spline smoothing plot, the turning points for BMI, WC, and WHtR were 26.1 kg/m² , 90.0 cm, and 0.50, respectively, and a J-shaped relationship was found for BMI (the likelihood ratio test, P <0.001). In the multiple logistic regressions, BMI ≥27.0 kg/m² , WC ≥90.0 cm and WHtR ≥0.50 were associated with higher risk of localized Stage II/III periodontitis than their counterparts (24.0 to 26.9 kg/m² for BMI) (odds ratios [OR] and 95% confidence intervals: 4.16 [1.39 to 12.49], 2.65 [1.01 to 7.11], and 2.95 [1.20 to 7.24], respectively; all P values <0.05). However, the risk for BMI <24.0 kg/m² was not significant (OR, 1.47 [0.47 to 4.54]).

CONCLUSION

In young adults, obesity defined by various anthropometrics was consistently associated with localized Stage II/III periodontitis and a J-shaped association was suggestive for BMI.

Biosensor and Lab-on-a-chip Biomarker-identifying Technologies for Oral and Periodontal Diseases

Periodontitis is a complex multifactorial disease that can lead to destruction of tooth supporting tissues and subsequent tooth loss. The most recent global burden of disease studies highlight that severe periodontitis is one of the most prevalent chronic inflammatory conditions affecting humans. Periodontitis risk is attributed to genetics, host-microbiome and environmental factors. Empirical diagnostic and prognostic systems have yet to be validated in the field of periodontics. Early diagnosis and intervention prevents periodontitis progression in most patients. Increased susceptibility and suboptimal control of modifiable risk factors can result in poor response to therapy, and relapse. The chronic immune-inflammatory response to microbial biofilms at the tooth or dental implant surface is associated with systemic conditions such as cardiovascular disease, diabetes or gastrointestinal diseases. Oral fluid-based biomarkers have demonstrated easy accessibility and potential as diagnostics for oral and systemic diseases, including the identification of SARS-CoV-2 in saliva. Advances in biotechnology have led to innovations in lab-on-a-chip and biosensors to interface with oral-based biomarker assessment. This review highlights new developments in oral biomarker discovery and their validation for clinical application to advance precision oral medicine through improved diagnosis, prognosis and patient stratification. Their potential to improve clinical outcomes of periodontitis and associated chronic conditions will benefit the dental and overall public health.

Systemic treatment with alpha-tocopherol and/or sodium selenite decreases the progression of experimental periodontitis

OBJECTIVE

To investigate the effects of sodium selenite (Se) and/or α-tocopherol (αT) applications on the alveolar bone loss (ABL), the number of gingival collagen fibers, inducible nitric oxide synthase (iNOS)+ and CD95+ cell numbers, and serum cytokine concentrations in experimental periodontitis in rats.

MATERIALS AND METHODS

Forty Sprague Dawley rats were divided into four groups of ten as follows: group A: Se group, group B: αT group, group C: Se and αT combined group, and group D: control group (intraperitoneal (IP) saline injection applied). Using the image analysis method in the connective tissue under the connective epithelium, the numbers of iNOS, CD95 positive cells, and collagen fibers were counted. ELISA kits were used to test the concentrations of serum interleukin (IL)-1β, IL-6, and IL-4.

RESULTS

The combination of Se and αT (group C) suppressed ABL compared with the control group (group D) (P < 0.05). In group A (Se), the number of iNOS+ cells was smaller than in group D (P < 0.05).

CONCLUSION

Se has been concluded to inhibit inflammation of the gum due to iNOS. Se and αT can have a remarkable important role in preventing alveolar bone loss, and particularly in combination.

CLINICAL RELEVANCE

Se and/or αT application may be useful in preventing the destruction of periodontal tissue and treatment of periodontal disease.

Evaluation of Salivary Matrix Metalloproteinase (MMP-8) in Periodontal Patients Undergoing Non-Surgical Periodontal Therapy and Mouthwash Based on Ozonated Olive Oil: A Randomized Clinical Trial

Background: Extracellular matrix metalloproteinases (MMPs) play a pivotal role in the damage to the periodontal tissue in patients with periodontitis. Scaling and root planning (SRP) attempt to control the plaque amount and consequentially reduce the bacterial load. Non-surgical periodontal treatment could be integrated with drug therapy and physiotherapy procedures such as ozone therapy. The aim of this study was to evaluate in a cohort of patients with a diagnosis of periodontitis: (1) the efficacy of non-surgical periodontal therapy assisted by the use of ozonated olive oil-based mouthwash on salivary metalloproteinase (MMP-8) and (2) the reduction of periodontal indices. Methods: Ninety-six subjects with a diagnosis of periodontitis were enrolled in this study and randomly assigned to the study group (SRP + mouthwash) or control group (SRP). The study duration was 3 months. Data on MMP-8, plaque index (PI), bleeding on probing (BoP) and probing pocket depth (PPD) were recorded at T0, T1 (14 days), T2 (1 month) and T3 (6 months). Group differences were assessed using Student’s t-test for independent samples. Results: A significant improvement in PI, BoP, PPD and salivary MMP-8 levels was observed in both groups. An analysis of differences in relative changes of indices revealed the efficacy of ozonated olive oil in decreasing MMP-8 level. Simultaneously, it slowed the decrease of BoP index. Conclusions: Scaling and root plaining with the aid of ozonated olive oil mouthwash were found to be more effective on salivary MMP-8 reduction than scaling and root plaining alone.

Post-periodontal surgery propounds early repair salivary biomarkers by 1H NMR based metabolomics

INTRODUCTION

Oral microflora is a well-orchestrated and acts as a sequential defense mechanism for any infection related to oral disease. Chronic periodontitis is a disease of a microbial challenge to symbiosis and homeostasis. Periodontal surgery is the most promising cure with repair process during periodontal regeneration. It has an encouraging outcome in terms of early recovery biomarkers.

OBJECTIVE

Saliva of periodontal surgery subjects with the chronic periodontitis have been evaluated by ¹H NMR spectroscopy in search of possible early metabolic differences that could be obtained in order to see the eradication of disease which favours the symbiotic condition.

METHOD

The study employed ¹H NMR spectroscopy on 176 human saliva samples in search of distinctive differences and their spectral data were further subjected to multivariate and quantitative analysis.

RESULT

The ¹H NMR study of periodontal surgery samples shows clear demarcation and profound metabolic differences when compared with the diseased condition. Several metabolites such as lactate, ethanol, succinate, and glutamate were found to be of higher significance in periodontal surgery in contrast to chronic periodontitis subjects. The PLS-DA model of the studied group resulted in R² of 0.83 and Q² of 0.70.

CONCLUSION

Significant metabolites could be considered as early repair markers for chronic periodontitis disease as they are being restored to achieve symbiosis. The study, therefore, concluded the early recovery process of the diseased subjects with the restoration of possible metabolomic profile similar to the healthy controls.

Biodegradable Polymer Films with a Natural Antibacterial Extract as Novel Periodontal Barrier Membranes

Biodegradable composite membranes containing propolis were produced from PCL/PLLA blends using a simple and low-cost solvent casting method, and subsequently their physicochemical, mechanical, and antibacterial properties were characterized. SEM analysis revealed that the addition of propolis has created honeycomb-like structures on the film surfaces. The flexibility of the films increased in the presence of propolis, which may provide ease of use during application. Propolis disrupted the organized structure of both polymers at the molecular level and caused decreases in the melting points. The films with propolis showed faster degradation in physiological conditions due to this molecular disruption. Moreover, the PLLA/PCL/propolis composite films exhibited remarkable antibacterial activities against S. aureus. Collectively, the data suggest that the produced films might be used as an alternative to exiting barrier membranes in guided tissue regeneration.

Cytokine levels in gingival crevicular fluid during orthodontic treatment with aligners compared to conventional labial fixed appliances: a 3-week clinical study

Objective: To test the hypothesis that the levels of IL-1ß and TNF-α increased more and IL-1α, IL-2, IL-6, IL-8 increased less, after 3 weeks of treatment with conventional labial fixed appliance and with aligners. Material and methods: Forty patients who were treated either with labial brackets (n = 20) or aligners (n = 20). Gingival crevicular fluid (GCF) samples were collected at baseline and after 21 days. Cytokine levels were evaluated by enzyme-linked immune sorbent assay (ELISA). Plaque index (PI), gingival index (GI), and bleeding on probing (POB) were also examined. Results: The levels of IL-1α, IL-1ß, IL-2, IL-6, IL-8 and TNF-α in the GCF were significantly increased in both groups. The levels of IL-2, IL-6, IL-8 increased more in patients treated with aligners compared to those treated by labial fixed appliances. There was a statistically significant difference in change of the mean cytokine levels of IL-1α, IL-2, IL-6, IL-8 and TNF-α compared to labial fixed appliances and aligners. Conclusions: The levels of the six studied cytokines in GCF (IL-1α, IL-1ß, IL-2, IL-6, IL-8 and TNF-α) increased after 3 weeks both after treatment with conventional labial fixed appliance and with aligners. IL-1ß and TNF-α showed a prominent increase compared to the other cytokines in the GCF of teeth by both the labial fixed appliance and aligners. However, there were only minor differences in the changes of the cytokine levels from baseline to 3 weeks between the two groups. There were no differences between the groups regarding PI, GI or POB.

Up-regulated ferritin in periodontitis promotes inflammatory cytokine expression in human periodontal ligament cells through transferrin receptor via ERK/P38 MAPK pathways

OBJECTIVE

Ferritin, an iron-binding protein, is ubiquitous and highly conserved; it plays a crucial role in inflammation, which is the main symptom of periodontitis. Full-length cDNA library analyses have demonstrated abundant expression of ferritin in human periodontal ligament. The aims of the present study were to explore how ferritin is regulated by local inflammation, and to investigate its functions and mechanisms of action in the process of periodontitis.

METHODS

Human gingival tissues were collected from periodontitis patients and healthy individuals. Experimental periodontitis was induced by ligature of second molars in mice. The expression of ferritin light polypeptide (FTL) and ferritin heavy polypeptide (FTH) were assessed by immunohistochemistry. Meanwhile, after stimulating human periodontal ligament cells (HPDLCs) with P. gingivalis-lipopolysaccharide (LPS), interleukin (IL)-6, and tumor necrosis factor-α (TNF-α), the expression of FTH and FTL were measured. Then, IL-6 and IL-8 were measured after incubation with different concentrations of apoferritin (iron-free ferritin) and several intracellular signaling pathway inhibitors, or after knockdown of the transferrin receptor.

RESULTS

Both FTH and FTL were substantially higher in inflamed periodontal tissues than in healthy tissues. The location of the elevated expression correlated well with the extent of inflammatory infiltration. Moreover, expression of FTH and FTL were enhanced after stimulation with P. gingivalis-LPS, IL-6, TNF-α. Apoferritin induced the production of IL-6 and IL-8 in a dose-dependent manner partly through binding to the transferrin receptor and activating ERK/P38 signaling pathways in HPDLCs.

CONCLUSIONS

Ferritin is up-regulated by inflammation and exhibits cytokine-like activity in HPDLCs inducing a signaling cascade that promotes expression of pro-inflammatory cytokines associated with periodontitis.

Development and in vitro evaluation of chitosan based system for local delivery of atorvastatin for treatment of periodontitis

In recent years, statin group drugs have been widely investigated in treatment of periodontal diseases due to their anti-inflammatory effect. The efficacy of statins can be enhanced by local administration into the periodontal pocket by appropriate delivery systems. The aim of our study was to develop a bioadhesive delivery system for local delivery of atorvastatin in treatment of periodontal disease. For this purpose, gel formulations were prepared using different types of chitosan (base and water soluble) and viscosity, bioadhesivity and syringeability of the gels as well as in vitro drug release properties were investigated vitro. Furthermore, anti-inflammatory effect of the formulations was studied in vitro using tumor necrosis factor (TNF)-alfa induced human gingival fibroblast (hGF) cells. Release of proinflammatory (IL-1β, IL-6, IL-8) and anti-inflammatory (TGF-β1, TGF-β2, TGF-β3, IL-10) cytokines were measured after incubating the hGF cells with the formulations. The viscosity of the formulations was found to be suitable for a local application into periodontal pocket. In presence of drug, bioadhesive property of the formulations was found to increase, and bioadhesion force was within the range, which would retain the delivery system at the application site, subsequently maintain drug levels at desired amount for longer period of time. The release of atorvastatin from the gels was found to be slower than that of the solution. The cytokine levels were found to decrease following application of the formulations, and anti-inflammatory effect was observed to enhance in presence of chitosan. No significant differences were found between base and water-soluble chitosan.

Angelica gigas ameliorates the destruction of gingival tissues via inhibition of MMP-9 activity

Angelica gigas (AG) has been used for periodontal diseases in traditional Korean medicine.

Manipulation of Neutrophils by Porphyromonas gingivalis in the Development of Periodontitis

The pathogenesis of the chronic periodontal disease is associated with a skewed host inflammatory response to periodontal pathogens, such as Porphyromonas gingivalis, that accounts for the majority of periodontal tissue damage. Neutrophils are the most abundant leukocytes in periodontal pockets and depending on the stage of the disease, also plentiful PMNs are present in the inflamed gingival tissue and the gingival crevice. They are the most efficient phagocytes and eliminate pathogens by a variety of means, which are either oxygen-dependent or -independent. However, these secretory lethal weapons do not strictly discriminate between pathogens and host tissue. Current studies describe conflicting findings about neutrophil involvement in periodontal disease. On one hand literature indicate that hyper-reactive neutrophils are the main immune cell type responsible for this observed tissue damage and disease progression. Deregulation of neutrophil survival and functions, such as chemotaxis, migration, secretion of antimicrobial peptides or enzymes, and production of reactive oxygen species, contribute to observed tissue injury and the clinical signs of periodontal disease. On the other hand neutrophils deficiencies in patients and mice also result in periodontal phenotype. Therefore, P. gingivalis represents a periodontal pathogen that manipulates the immune responses of PMNs, employing several virulence factors, such as gingipains, serine proteases, lipid phosphatases, or fimbriae. This review will sum up studies devoted to understanding different strategies utilized by P. gingivalis to manipulate PMNs survival and functions in order to inhibit killing by a granular content, prolong inflammation, and gain access to nutrient resources.

Direct expression of active human tissue inhibitors of metalloproteinases by periplasmic secretion in Escherichia coli

Background

As regulators of multifunctional metalloproteinases including MMP, ADAM and ADAMTS families, tissue inhibitors of metalloproteinases (TIMPs) play a pivotal role in extracellular matrix remodeling, which is involved in a wide variety of physiological processes. Since abnormal metalloproteinase activities are related to numerous diseases such as arthritis, cancer, atherosclerosis, and neurological disorders, TIMPs and their engineered mutants hold therapeutic potential and thus have been extensively studied. Traditional productions of functional TIMPs and their N-terminal inhibitory domains (N-TIMPs) rely on costly and time-consuming insect and mammalian cell systems, or tedious and inefficient refolding from denatured inclusion bodies. The later process is also associated with heterogeneous products and batch-to-batch variation.

Results

In this study, we developed a simple approach to directly produce high yields of active TIMPs in the periplasmic space of Escherichia coli without refolding. Facilitated by disulfide isomerase (DsbC) co-expression in protease-deficient strain BL21 (DE3), N-TIMP-1/-2 and TIMP-2 which contain multiple disulfide bonds were produced without unwanted truncations. 0.2–1.4 mg purified monomeric TIMPs were typically yielded per liter of culture media. Periplasmically produced TIMPs exhibited expected inhibition potencies towards MMP-1/2/7/14, and were functional in competitive ELISA to elucidate the binding epitopes of MMP specific antibodies. In addition, prepared N-TIMPs were fully active in a cellular context, i.e. regulating cancer cell morphology and migration in 2D and 3D bioassays.

Conclusion

Periplasmic expression in E. coli is an excellent strategy to recombinantly produce active TIMPs and N-TIMPs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12934-017-0686-9) contains supplementary material, which is available to authorized users.

The Role of Proteinase-Activated Receptors 1 and 2 in the Regulation of Periodontal Tissue Metabolism and Disease

Proteinase-activated receptors 1 (PAR1) and 2 (PAR2) are the most highly expressed members of the PAR family in the periodontium. These receptors regulate periodontal inflammatory and repair processes through their activation by endogenous and bacterial enzymes. PAR1 is expressed by the periodontal cells such as human gingival fibroblasts, gingival epithelial cells, periodontal ligament cells, osteoblasts, and monocytic cells and can be activated by thrombin, matrix metalloproteinase 1 (MMP-1), MMP-13, fibrin, and gingipains from Porphyromonas gingivalis. PAR2 is expressed by neutrophils, osteoblasts, oral epithelial cells, and human gingival fibroblasts, and its possible activators in the periodontium are gingipains, neutrophil proteinase 3, and mast cell tryptase. The mechanisms through which PARs can respond to periodontal enzymes and result in appropriate immune responses have until recently been poorly understood. This review discusses recent findings that are beginning to identify a cardinal role for PAR1 and PAR2 on periodontal tissue metabolism.

Expression of matrix metalloproteinases-2, -9 and reversion-inducing cysteine-rich protein with Kazal motifs in gingiva in periodontal health and disease

BACKGROUND AND OBJECTIVE

Periodontitis is characterized by pathological destruction of extracellular matrix (ECM) of periodontal tissues. Matrix metalloproteinases (MMPs) promote the occurrence and development of periodontitis by degrading almost all proteins of ECM. RECK (reversion-inducing-cysteine-rich protein with kazal motifs), a novel membrane-anchored inhibitor of MMPs, could regulate the expression of MMP-2 and MMP-9 at post-transcriptional level. The study was to investigate the expression of RECK in healthy and diseased human gingival tissues and to correlate it with the production of MMP-2 and MMP-9.

MATERIAL AND METHODS

Gingival biopsies were collected from chronic periodontitis patients and periodontally healthy control individuals. The protein and mRNA of RECK, MMP-2 and MMP-9 was determined by immunohistochemistry and semi-quantitative polymerase chain reaction analysis.

RESULTS

The expression of RECK protein was mainly confined to the gingival epithelium in inflamed and non-inflamed gingival tissues. Expression of RECK was significantly lower in tissues from chronic periodontitis patients, while the positive expression levels of MMP-2 and MMP-9 in periodontitis specimens were significantly higher. RECK protein expression was negatively correlated to the expressions of MMP-2 and MMP-9 in periodontitis. Moreover, RECK mRNA was significanly lower in diseased gingiva than in healthy samples(P<0.05), while MMP-2 and MMP-9 mRNAs were observed overexpressed in periodontal lesions, with no significant correlation between RECK and MMP-2/MMP-9 mRNA shown in periodontally diseased group.

CONCLUSION

The expression of RECK in human healthy and diseased gingiva may contribute to periodontal physiological and pathological processes; low RECK expression may be associated with the enhanced MMP-2 and MMP-9 production in inflamed gingiva.

Histochemical detection and comparison of apoptotic cells in the gingival epithelium using hematoxylin and eosin and methyl green-pyronin: A pilot study

BACKGROUND

Apoptosis plays a critical role in the regulation of inflammation and host immune response. It helps in tissue homeostasis and a disturbance in this is often associated with disease. The use of histochemical stains like hematoxylin and eosin (H and E) and methyl green-pyronin (MGP) can provide a simple and cost-effective method for the detection of apoptotic cells.

AIM

Study intended to analyze the expression of apoptosis in the gingival epithelium of healthy subjects and in patients with chronic periodontitis, using H and E and MGP. It is also proposed to correlate the apoptotic index (AI) of healthy individuals and those with chronic periodontitis.

MATERIALS AND METHODS

Twenty gingival biopsies were harvested from which ten samples were of healthy subjects and ten subjects who suffered from chronic periodontitis. Apoptotic cells were analyzed using MGP and H and E under light microscopy.

RESULTS

Apoptotic cells were identified at ×100 magnification and AI was calculated. Apoptotic cells were easily distinguishable in MGP stained sections when compared to those stained using H and E. Moreover, apoptotic cell count was higher in chronic periodontitis. Statistical analyses were done by Tukey's multiple post hoc procedure.

CONCLUSION

The study reveals that MGP staining can be used in a routine basic laboratory set up as one of the cost-effective methods for the detection of apoptotic cells.

Aggregatibacter actinomycetemcomitans outer membrane protein 29 (Omp29) induces TGF-β-regulated apoptosis signal in human gingival epithelial cells via fibronectin/integrinβ1/FAK cascade

Gingival junctional epithelial cell apoptosis caused by periodontopathic bacteria exacerbates periodontitis. This pathological apoptosis is involved in the activation of transforming growth factor β (TGF-β). However, the molecular mechanisms by which microbes induce the activation of TGF-β remain unclear. We previously reported that Aggregatibacter actinomycetemcomitans (Aa) activated TGF-β receptor (TGF-βR)/smad2 signalling to induce epithelial cell apoptosis, even though Aa cannot bind to TGF-βR. Additionally, outer membrane protein 29 kDa (Omp29), a member of the Aa Omps family, can induce actin rearrangements via focal adhesion kinase (FAK) signalling, which also plays a role in the activation of TGF-β by cooperating with integrin. Accordingly, we hypothesized that Omp29-induced actin rearrangements via FAK activity would enhance the activation of TGF-β, leading to gingival epithelial cell apoptosis in vitro. By using human gingival epithelial cell line OBA9, we found that Omp29 activated TGF-βR/smad2 signalling and decreased active TGF-β protein levels in the extracellular matrix (ECM) of cell culture, suggesting the transactivation of TGF-βR. Inhibition of actin rearrangements by cytochalasin D or blebbistatin and knockdown of FAK or integrinβ1 expression by siRNA transfection attenuated TGF-βR/smad2 signalling activity and reduction of TGF-β levels in the ECM caused by Omp29. Furthermore, Omp29 bound to fibronectin (Fn) to induce its aggregation on integrinβ1, which is associated with TGF-β signalling activity. All the chemical inhibitors and siRNAs tested blocked Omp29-induced OBA9 cells apoptosis. These results suggest that Omp29 binds to Fn in order to facilitate Fn/integrinβ1/FAK signalling-dependent TGF-β release from the ECM, thereby inducing gingival epithelial cell apoptosis via TGF-βR/smad2 pathway.

The pro-apoptotic and pro-inflammatory effects of calprotectin on human periodontal ligament cells

Calprotectin, a heterodimer of S100A8 and S100A9 subunits, is associated with inflammatory disorders such as rheumatoid arthritis and cystic fibrosis. Although calprotectin levels are increased significantly in the gingival crevicular fluid (GCF) of periodontitis patients, its effects on periodontal ligament cells (PDLCs) remain largely unknown. The aim of this study was to evaluate calprotectin levels in the GCF of generalized aggressive periodontitis (AgP) patients and to investigate the effects of recombinant human calprotectin (rhS100A8/A9) and its subunits (rhS100A8 and rhS100A9) in PDLCs. Both the concentration and amount of crevicular calprotectin were significantly higher in the AgP group compared with healthy controls. In addition, the GCF calprotectin levels were correlated positively with clinical periodontal parameters including bleeding index, probing depth, and clinical attachment loss. rhS100A8/A9 promoted cell apoptosis, whereas rhS100A8 and rhS100A9 individually exerted little effect on apoptosis in PDLCs. rhS100A9 and rhS100A8/A9 increased the activation of nuclear factor-κB (NF-κB) by promoting the nuclear translocation of p65 in PDLCs, subsequently inducing expression of the pro-inflammatory cytokines IL-6, IL-8, TNFα, and COX2. Treatment with an NF-κB inhibitor partially reversed the rhS100A9- and rhS100A8/A9-induced upregulation of the pro-inflammatory cytokines. rhS100A9, and not rhS100A8, was mainly responsible for the pro-inflammatory role of calprotectin. Collectively, our results suggest that calprotectin promotes apoptosis and the inflammatory response in PDLCs via rhS100A9. These findings might help identify novel treatments for periodontitis.

Identification of transactivation-responsive DNA-binding protein 43 (TARDBP43; TDP-43) as a novel factor for TNF-α expression upon lipopolysaccharide stimulation in human monocytes

BACKGROUND AND OBJECTIVE

Tumor necrosis factor alpha (TNF-α) is a major cytokine implicated in various inflammatory diseases. The nature of the nuclear factors associated with human TNF-α gene regulation is not well elucidated. We previously identified a novel region located from -550 to -487 in human TNF-α promoter that did not contain the reported binding sites for nuclear factor kappa B (NF-κB) but showed lipopolysaccharide (LPS)-induced transcriptional activity. The purpose of this study is to identify novel factors that bind to the promoter region and regulate TNF-α expression.

MATERIAL AND METHODS

To identify DNA-binding proteins that bound to the target region of TNF-α promoter, a cDNA library from LPS-stimulated human monocytic cell line THP-1 was screened using a yeast one-hybrid system. Cellular localizations of the DNA-binding protein in the cells were examined by subcellular immunocytochemistry. Nuclear amounts of the protein in LPS-stimulated THP-1 cells were identified by western blot analysis. Expression of mRNA of the protein in the cells was quantified by real-time polymerase chain reaction. Electrophoretic mobility shift assays were performed to confirm the DNA-binding profile. Overexpression of the protein and knockdown of the gene were also performed to investigate the role for TNF-α expression.

RESULTS

Several candidates were identified from the cDNA library and transactivation-responsive DNA-binding protein 43 (TARDBP43; TDP-43) was focused on. Western blot analysis revealed that nuclear TDP-43 protein was increased in the LPS-stimulated THP-1 cells. Expression of TDP-43 mRNA was already enhanced before TNF-α induction by LPS. Electrophoretic mobility shift assay analysis showed that nuclear extracts obtained by overexpressing FLAG-tagged TDP-43 bound to the -550 to -487 TNF-α promoter fragments. Overexpression of TDP-43 in THP-1 cells resulted in an increase of TNF-α expression. Knockdown of TDP-43 in THP-1 cells downregulated TNF-α expression.

CONCLUSION

We identified TDP-43 as one of the novel TNF-α factors and found that it bound to the LPS-responsive element in the TNF-α promoter to increase TNF-α expression.

The relationship between matrix metalloproteinases (MMP-3, -8, -9) in serum and peripheral lymphocytes (CD8+ , CD56+ ) in Down syndrome children with gingivitis

BACKGROUND AND OBJECTIVE

Altered immune response may be a major contributor to periodontal disease in Down syndrome. This study investigated the relationship between peripheral lymphocytes and matrix metalloproteinases (MMPs) in serum in Down syndrome children with gingivitis.

MATERIAL AND METHODS

Children with Down syndrome (n = 10) and healthy controls (n = 10) were clinically and radiographically examined during dental treatment under general anaesthesia. Peripheral blood and gingival crevicular fluid were collected from each subject and concentrations were determined: serum MMP-2, -3, -8 and -9; serum tissue inhibitors of metalloproteinases (TIMP) -1, -2 and -3; and gingival crevicular fluid. Leukocytes were isolated from peripheral blood and the relative amounts (%) of the various cell phenotypes were analysed using flow cytometry. In addition, peripheral blood cells were treated with Porphyromonas gingivalis lipopolysaccharide and levels of MMPs and TIMPs measured.

RESULTS

Concentrations of MMP-3, MMP-8 and TIMP-1 in serum were significantly higher (p < 0.05) in the Down syndrome group compared to the controls. When peripheral blood leukocytes were cultured in the presence or absence of P. gingivalis lipopolysaccharide, MMP-8 levels were significantly (p < 0.05) higher in the Down syndrome group compared to controls. Children with Down syndrome exhibited significant positive correlations between CD8(+) T cells and MMP-8 (r = 0.630; p = 0.050), between CD8(+) T cells and MMP-9 (r = 0.648; p = 0.043), and between CD56(+) NK cells and MMP-3 (r = 0.828; p = 0.003) compared to controls.

CONCLUSIONS

The positive relationship of serum MMP-3, -8 and -9 with immune cells in children with Down syndrome may facilitate migration of CD8(+) T cells and CD56(+) NK cells into the periodontal tissue, which may contribute to the increased degradation of periodontal tissue in individuals with Down syndrome.

Texture and topography analysis of doxycycline hyclate thermosensitive systems comprising zinc oxide

To characterize the thermal behavior and texture analysis of doxycycline hyclate thermosensitive gels developed for periodontitis treatment containing zinc oxide prepared by using poloxamer (Lutrol^® F127) as polymeric material and N-methyl pyrrolidone was used as cosolvent. The thermosensitive gel comprising doxycycline hyclate, Lutrol^® F127, and N-methyl pyrrolidone were characterized for the thermal behavior and texture analysis. The topography of the system after the dissolution test was characterized with scanning electron microscope. Differential scanning calorimetric thermogram exhibited the endothermic peaks in the systems containing high amount of N-methyl pyrrolidone in solvent. The sol-gel transition temperature of the systems decreased as the zinc oxide amount was increased. The addition of doxycycline hyclate, zinc oxide, and N-methyl pyrrolidone affected the syringeability of systems. The addition of zinc oxide into the doxycycline hyclate-Lutrol^® F127 systems decreased the diameter of inhibition zone against Staphylococcus aureus, Escherichia coli, and Candida albicans since zinc oxide decreased the diffusion and prolonged release of doxycycline hyclate. From scanning electron microscope analysis, the porous surface of 20% w/w Lutrol^® F127 system was notably different from that of gel comprising doxycycline hyclate which had interconnected pores and smooth surfaces. The number of pores was decreased with increasing zinc oxide and the porous structure was smaller and more compact. Therefore, the addition of zinc oxide could increase the syringeability of doxycycline hyclate-Lutrol^® F127 system with the temperature dependence. Zinc oxide decreased inhibition zone against test microbes because of prolongation of doxycycline hyclate release and reduced size of continuous cells. Furthermore, zinc oxide also increased the compactness of wall surfaces of Lutrol^® F127.

Rheumatoid Arthritis among Periodontitis Patients in Baddi Industrial Estate of Himachal Pradesh, India: A Cross Sectional Study

AIM

To determine whether there is a relationship between periodontal disease and rheumatoid arthritis.

METHODS

A total of 1520 (852 - periodontal group; 668 - general group) individuals of 30-70 years age group and residents of Baddi industrial estate in Himachal Pradesh, India, were assessed for the prevalence of rheumatoid arthritis and Periodontal Disease (PD). The prevalence and severity of periodontitis were determined by recording the Community Periodontal Index (CPI) with loss of attachment, based on WHO guidelines (1997). The criteria considered for diagnosis of rheumatoid arthritis were as those given by American Rheumatism Association -1988. Frequency distributions for bivariate analysis and logistic regression for multivariate analysis were used for assessment of statistical association between variables.

RESULTS

In patients referred for periodontal treatment, the prevalence of rheumatoid arthritis was 4.4%. Females (3.2%) and subjects aged above 50 years (3.5%) showed a significantly higher prevalence in comparison to their counterparts (p<0.001). The odds of rheumatoid arthritis in females were nearly three times (OR=2.813) higher than those in males, which was also statistically significant (p<0.05).

CONCLUSION

The findings provide evidence of a relationship, suggesting that individuals with moderate to severe periodontal disease are at higher risk of suffering from rheumatoid arthritis and vice versa.

Inflammatory mediators in the pathogenesis of periodontitis

Periodontitis is a chronic inflammatory condition of the periodontium involving interactions between bacterial products, numerous cell populations and inflammatory mediators. It is generally accepted that periodontitis is initiated by complex and diverse microbial biofilms which form on the teeth, i.e. dental plaque. Substances released from this biofilm such as lipopolysaccharides, antigens and other virulence factors, gain access to the gingival tissue and initiate an inflammatory and immune response, leading to the activation of host defence cells. As a result of cellular activation, inflammatory mediators, including cytokines, chemokines, arachidonic acid metabolites and proteolytic enzymes collectively contribute to tissue destruction and bone resorption. This review summarises recent studies on the pathogenesis of periodontitis, with the main focus on inflammatory mediators and their role in periodontal disease.

mRNA expression of MMP-28 (Epilysin) in gingival tissues of chronic and aggressive periodontitis patients: a reverse transcriptase PCR study

Background and Objectives. Matrix metalloproteinases degrade extracellular membrane and also release bioactive fragments and growth factors, thus influencing fundamental biological and pathological processes. Epilysin (MMP-28) differs from most other MMPs as it is expressed in a number of normal tissues, suggestive of functions in tissue homeostasis. The aim of the present study was to quantitatively evaluate and compare the mRNA expression of epilysin (MMP-28) in gingival tissues of healthy patients and of patients affected by chronic or aggressive periodontitis. Methods. A total of 60 subjects, 20 periodontally healthy subjects, 20 with chronic periodontitis, and 20 with aggressive periodontitis, were included in this study. Periodontal status was evaluated by measuring gingival index, probing depth and clinical attachment level. mRNA expression of MMP-28 was determined by quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR) in gingival tissue samples collected. Results. Relative quantification of mRNA expression of MMP-28 was highest in healthy tissues (RQ = 0.97) when compared to subjects with chronic periodontitis (RQ = 0.37) and aggressive periodontitis (RQ = 0.23), but the difference was not statistically significant. Conclusion. mRNA expression of MMP-28 was highest in healthy tissues when compared to diseased periodontal tissues suggesting that MMP-28 could act as a biomarker for periodontal health.

Tumor necrosis factor-α induces matrix metalloproteinases-3, -10, and -13 in human periodontal ligament cells

BACKGROUND

Various biologic mediators, including matrix metalloproteinases (MMPs), that are implicated in periodontal tissue breakdown can be induced by cytokines. MMPs are known to degrade periodontal ligament attachment, and bone matrix proteins and tissue inhibitors of metalloproteinase (TIMPs) inhibit the activity of MMPs. The aim of this study is to investigate the effect of tumor necrosis factor (TNF)-α on the expression of MMPs in human periodontal ligament (PDL) cells in vitro and establish which MMPs are expressed specifically in response to that stimulus.

METHODS

Cultured PDL cells were stimulated with TNF-α and analyzed with an MMP antibody array. Real-time polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and western blot with cell lysate and zymography were used to measure messenger RNA (mRNA) and protein levels of MMP-3, -10, and -13. To examine TNF receptor (TNFR) expression, PDL cells were examined by flow cytometry, and expression of MMP-3, -10, and -13 was observed after blocking the TNFR with an antagonist. Results from real-time PCR, ELISA, and western blot were analyzed by paired t test.

RESULTS

The antibody array showed that the protein most strongly upregulated by TNF-α stimulation was MMP-3, followed by MMP-13 and MMP-10. The TNF-α receptor blocker specifically inhibited expression of MMP-3 and -13. In addition, TNF-α increased levels of MMP mRNAs in MMP-3, -13, and -10 (in decreasing order). However, ELISAs showed that MMP-13 was the most upregulated protein, followed by MMP-10 and MMP-3. Western blotting indicated that TNF-α increased MMP-3 and -13 levels but had no significant effect on the level of MMP-10, and zymography showed that TNF-α increased the activities of all forms of MMP-3 and -13, but MMP-10 was not detected. Flow cytometry demonstrated that the majority of PDL cells expressed TNFR1.

CONCLUSIONS

TNF-α (10 ng/mL) upregulates levels of MMP-3, -10, and -13 in human PDL cells. These results suggest that these proteins play an important role in the inflammation of PDLs.

Engineering three-dimensional constructs of the periodontal ligament in hyaluronan-gelatin hydrogel films and a mechanically active environment

BACKGROUND AND OBJECTIVE

Periodontal ligament (PDL) cells in stationary two-dimensional culture systems are in a double default state. Our aim therefore was to engineer and characterize three-dimensional constructs, by seeding PDL cells into hyaluronan-gelatin hydrogel films (80-100 μm) in a format capable of being mechanically deformed.

MATERIAL AND METHODS

Human PDL constructs were cultured with and without connective tissue growth factor (CTGF) and fibroblast growth factor (FGF)-2 in (i) stationary cultures, and (ii) mechanically active cultures subjected to cyclic strains of 12% at 0.2 Hz each min, 6 h/d, in a Flexercell FX-4000 Strain Unit. The following parameters were measured: cell number and viability by laser scanning confocal microscopy; cell proliferation with the MTS assay; the expression of a panel of 18 genes using real-time RT-PCR; matrix metalloproteinases (MMPs) 1-3, TIMP-1, CTGF and FGF-2 protein levels in supernatants from mechanically activated cultures with Enzyme-linked immunosorbent assays. Constructs from stationary cultures were also examined by scanning electron microscopy and immunostained for actin and vinculin.

RESULTS

Although initially randomly distributed, the cells became organized into a bilayer by day 7; apoptotic cells remained constant at approximately 5% of the total. CTGF/FGF-2 stimulated cell proliferation in stationary cultures, but relative quantity values suggested modest effects on gene expression. Two transcription factors (RUNX2 and PPARG), two collagens (COL1A1, COL3A1), four MMPs (MMP-1-3, TIMP-1), TGFB1, RANKL, OPG and P4HB were detected by gel electrophoresis and Ct values < 35. In mechanically active cultures, with the exception of P4HB, TGFB1 and RANKL, each was upregulated at some point in the time scale, as was the synthesis of MMPs and TIMP-1. SOX9, MYOD, SP7, BMP2, BGLAP or COL2A1 were not detected in either stationary or mechanically active cultures.

CONCLUSION

Three-dimensional tissue constructs provide additional complexity to monolayer culture systems, and suggest some of the assumptions regarding cell growth, differentiation and matrix turnover based on two-dimensional cultures may not apply to cells in three-dimensional matrices. Primarily developed as a transitional in vitro model for studying cell-cell and cell-matrix interactions in tooth support, the system is also suitable for investigating the pathogenesis of periodontal diseases, and importantly from the clinical point of view, in a mechanically active environment.

Correlation of expression and activity of matrix metalloproteinase-9 and -2 in human gingival cells of periodontitis patients

Purpose

Matrix metalloproteinases (MMPs) are capable of degrading extracellular matrix, and they are inducible enzymes depending on an inflammatory environment such as periodontitis and bacterial infection in periodontal tissue. Gingival inflammation has been postulated to be correlated with the production of MMP-2 and MMP-9. The objective of this study was to quantify the expression and activity of MMP-9 and -2, and to determine the correlation between activity and expression of these MMPs in human gingival tissues with periodontitis.

Methods

The gingival tissues of 13 patients were homogenized in 500 µL of phosphate buffered saline with a protease inhibitor cocktail. The expression and activity of MMP-2 and -9 were measured by enzyme-linked immunosorbent assay and Western blot analysis, and quantified by a densitometer. For the correlation line, statistical analysis was performed using the Systat software package.

Results

MMP-9 was highly expressed in all gingival tissue samples, whereas MMP-2 was underexpressed compared with MMP-9. MMP-9 activity increased together with the MMP-9 expression level, with a positive correlation (r=0.793, P=0.01). The correlation was not observed in MMP-2.

Conclusions

The expression of MMP-2 and -9 might contribute to periodontal physiological and pathological processes, and the degree of MMP-9 expression and activity are predictive indicators relevant to the progression of periodontitis.

Host-bacteria crosstalk at the dentogingival junction

The dentogingival junction is of crucial importance in periodontal host defense both structurally and functionally. Oral bacteria exert a constant challenge to the host cells and tissues at the dentogingival junction. The host response is set up to eliminate the pathogens by the innate and adaptive defense mechanisms. In health, the commensal bacteria and the host defense mechanisms are in a dynamic steady state. During periodontal disease progression, the dental bacterial plaque, junctional epithelium (JE), inflammatory cells, connective tissue, and bone all go through a series of changes. The tissue homeostasis is turned into tissue destruction and progression of periodontitis. The classical study of Slots showed that in the bacterial plaque, the most remarkable change is the shift from gram-positive aerobic and facultatively anaerobic flora to a predominantly gram-negative and anaerobic flora. This has been later confirmed by several other studies. Furthermore, not only the shift of the bacterial flora to a more pathogenic one, but also bacterial growth as a biofilm on the tooth surface, allows the bacteria to communicate with each other and exert their virulence aimed at favoring their growth. This paper focuses on host-bacteria crosstalk at the dentogingival junction and the models studying it in vitro.

Association between chronic periodontitis and rheumatoid arthritis: a hospital-based case-control study

Rheumatoid arthritis (RA) and chronic periodontitis are the most common chronic inflammatory diseases with remarkable pathological and clinical similarities. A lot of similarities exist between RA and periodontitis at cellular and molecular levels. The relationship between these two chronic inflammatory diseases is still unclear. This case-control study was undertaken to determine the possible association between chronic inflammatory diseases like RA and periodontitis. The case group consisted of 100 patients attending the Rheumatology clinic who have rheumatoid arthritis (RA group). Age- and gender-matched 112 patients without RA attending the Outpatient wing of Department of General Medicine formed the control group (NRA group). The number of missing teeth, gingival index (GI), oral hygiene index-simplified (OHI-S), probing pocket depth (PPD) and clinical attachment levels (CAL) were evaluated in both the groups. Rheumatoid disease activity was assessed by DAS-28 score system. Systemic markers of inflammation like erythrocytic sedimentation rate (ESR) and serum levels of C-reactive protein (CRP) were assessed. There was a statistically significant difference in GI, OHI-S, PPD, CAL, ESR and CRP levels between cases (RA group) and controls (NRA group) (P < 0.05). Among subjects with RA, there was no association between the rheumatoid disease activity and the severity of periodontal disease. The occurrence and severity of periodontitis was found to be higher in RA subjects as compared to subjects without RA, suggesting a positive relation between these two chronic inflammatory diseases.

Tea polyphenols inhibit rat osteoclast formation and differentiation

Matrix metalloproteinases (MMPs) play an important role in degeneration of the matrix associated with bone and cartilage. Regulation of osteoclast activity is essential in the treatment of bone disease, including osteoporosis and rheumatoid arthritis. Polyphenols in green tea, particularly epigallocatechin-3-gallate (EGCG), inhibit MMPs expression and activity. However, the effects of the black tea polyphenol, theaflavin-3,3'-digallate (TFDG), on osteoclast and MMP activity are unknown. Therefore, we examined whether TFDG and EGCG affect MMP activity and osteoclast formation and differentiation in vitro. TFDG or EGCG (10 and 100 µM) was added to cultures of rat osteoclast precursors cells and mature osteoclasts. Numbers of multinucleated osteoclasts and actin rings decreased in polyphenol-treated cultures relative to control cultures. MMP-2 and MMP-9 activities were lower in TFDG- and EGCG-treated rat osteoclast precursor cells than in control cultures. MMP-9 mRNA levels declined significantly in TFDG-treated osteoclasts in comparison to control osteoclasts. TFDG and EGCG inhibited the formation and differentiation of osteoclasts via inhibition of MMPs. TFDG may suppress actin ring formation more effectively than EGCG. Thus, TFDG and EGCG may be suitable agents or lead compounds for the treatment of bone resorption diseases.

The effect of smoking on the mRNA expression of MMPs and TIMP-1 in untreated chronic periodontitis patients: a cross-sectional study

BACKGROUND AND OBJECTIVE

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are important for extracellular matrix. Expression of MMPs has been evaluated in gingiva without studying smoking. The aim of this study was to explore the effect of smoking on mRNA expression of MMP-1, -3, -8, -9 and -13 and TIMP-1 in untreated chronic periodontitis and in periodontal health.

MATERIAL AND METHODS

Gingival samples were harvested from 30 subjects with untreated chronic periodontitis (15 nonsmokers and 15 smokers) and 30 periodontally healthy subjects (15 nonsmokers and 15 smokers). Full-mouth plaque score, gingival index, bleeding on probing, probing depth and clinical attachment level were recorded. Total RNA was isolated, and the mRNA expression of MMPs and TIMP-1 was assessed by RT-PCR.

RESULTS

Periodontitis groups were comparable in clinical measurements. Nonsmoker subjects with periodontitis had statistically significantly higher MMP-1, lower MMP-9 and TIMP-1 expression and higher MMP-1/TIMP-1 ratio than smokers; and higher MMP-8 expression and MMP-8/TIMP-1 and MMP-1/TIMP-1 ratios than healthy nonsmokers. Healthy nonsmokers had statistically significantly higher MMP-13 expression than healthy smokers. Smoker periodontitis and healthy subjects had similar expression levels of MMPs and TIMP-1 and MMPs/TIMP-1 ratios. There was correlation among the MMPs only for smoker periodontitis subjects. Expression of MMP-13 was correlated with mean clinical attachment level.

CONCLUSION

Within its limits, this study demonstrated that smoking affected mRNA expression of MMPs and TIMP-1, MMPs/TIMP-1 ratios and relationships among MMPs in untreated chronic periodontitis and expression of MMPs in health. In the absence of smoking, chronic periodontitis affected expression of MMPs and MMPs/TIMP-1 ratios.

Host-derived diagnostic markers related to soft tissue destruction and bone degradation in periodontitis

BACKGROUND

A major challenge in clinical periodontics is to find a reliable molecular marker of periodontal tissue destruction with high sensitivity, specificity and utility.

OBJECTIVES

The aim of this systematic review is to evaluate available literature on 'the utility of molecular markers of soft and hard periodontal tissue destruction'.

MATERIALS AND METHODS

Based on the focused question, 'What is the utility of molecular markers of soft and hard periodontal tissue destruction', an electronic and manual search was conducted for human studies presenting clinical data for the potential of molecular markers of tissue destruction in biofluids; gingival crevicular fluid (GCF), saliva, and serum.

RESULTS

Papers fulfilling the inclusion criteria were selected. All relevant data from the selected papers were extracted and recorded in separate tables for molecules in GCF, saliva, and serum.

CONCLUSION

Within the defined limits of the Problem/Population, Intervention, Comparison, Outcome, the present analysis reveals that (a) no single or combination of markers exists that can disclose periodontal tissue destruction adequately; (b) while the most fruitful source of biomarkers for periodontal destruction appears to be in molecules tightly related to bone and soft tissue destruction, this remains to be objectively demonstrated. Currently, clinical measurements are still the most reliable.

Evaluation of the influence of ozonotherapy on the clinical parameters and MMP levels in patients with chronic and aggressive periodontitis

PURPOSE

A comparison of the clinical status and salivary MMP levels after SRP alone or with ozonotherapy in patients with aggressive and chronic periodontitis.

MATERIAL/METHODS

The study was performed in 52 generally healthy subjects with chronic or aggressive periodontitis. Group CP-S consisted of 12 patients with chronic periodontitis, who underwent scaling and root planing (SRP). In group CP-O there were 25 patients with chronic periodontitis who additionaly to SRP underwent ozonotherapy. The same therapy was performed in group AP, containing 15 patients with aggressive periodontitis. Plaque index, approximal plaque index, bleeding on probing, sulcus bleeding index, probing pocket depth and clinical attachment loss were measured at baseline, at two weeks and two months post-therapy. The levels of MMP-1, MMP-8 and MMP-9 were estimated in non-stimulated saliva with an ELISA method.

RESULTS

All the clinical parameters assessed in the study groups were reduced after treatment. SRP with additional ozonotherapy provided an increase in MMP levels in patients with chronic periodontitis and a reduction in MMP levels in patients with aggressive periodontitis.

CONCLUSIONS

SRP followed by ozonotherapy does not lead to further improvement in clinical periodontal parameters in patients with AP and CP.

Diabetes, periodontitis, and the subgingival microbiota

Both type 1 and type 2 diabetes have been associated with increased severity of periodontal disease for many years. More recently, the impact of periodontal disease on glycaemic control has been investigated. The role of the oral microbiota in this two-way relationship is at this stage unknown. Further studies, of a longitudinal nature and investigating a wider array of bacterial species, are required in order to conclusively determine if there is a difference in the oral microbiota of diabetics and non-diabetics and whether this difference accounts, on the one hand, for the increased severity of periodontal disease and on the other for the poorer glycaemic control seen in diabetics.

Nafamostat mesilate, a potent tryptase inhibitor, modulates periodontitis in rats

Previous reports have demonstrated increased tryptase-like proteolytic activity in the crevicular fluid of patients with periodontal disease. In the present study, we have investigated the effect of tryptase inhibition with nafamostat mesilate (NM, 6-amino-2-naphtlyl p-guanidinobenzoate dimethansulfonate) on the development of experimental periodontitis in rats. Eighty (80) male Wistar rats were randomly separated into four groups: Control group, NM group (daily 0.1 mg/kg body weight of NM, i.p.), Ligature group (ligature placed at lower right first molars), and NM+Ligature group. The amount of alveolar bone loss (ABL) around the mesial root surface of the first mandibulary molar, as well as the myeloperoxidase (MPO) activity, and total proteolytic activity [N-benzoyl-L: -arginine-p-nitroanilide (BApNA) substrate] were determined at 7 and 14 days. NM led to significantly (p < 0.05) decreased ABL in animals subjected to ligature-induced periodontitis. Tryptase inhibition prevented the onset of significant ABL at 7 days of experiment (0.44 ± 0.16 and 0.60 ± 0.22, p > 0.05, NM+Ligature and Control, respectively) and significantly decreased the ABL at 14 days (0.97 ± 0.17 versus 1.82 ± 0.26, p < 0.001, NM+Ligature versus Ligature, respectively). In addition, NM significantly decreased MPO and total proteolytic activity at 14 days (p < 0.05). These data provided evidence that tryptase inhibition with NM attenuates gingival granulocyte infiltration and ABL in an experimental model of periodontitis in rats.

Signal pathways JNK and NF-kappaB, identified by global gene expression profiling, are involved in regulation of TNFalpha-induced mPGES-1 and COX-2 expression in gingival fibroblasts

Background

Prostaglandin E₂ (PGE₂) is involved in several chronic inflammatory diseases including periodontitis, which causes loss of the gingival tissue and alveolar bone supporting the teeth. We have previously shown that tumor necrosis factor α (TNFα) induces PGE₂ synthesis in gingival fibroblasts. In this study we aimed to investigate the global gene expression profile of TNFα-stimulated primary human gingival fibroblasts, focusing on signal pathways related to the PGE₂-synthesizing enzymes prostaglandin E synthases (PGES), as well as the upstream enzyme cyclooxygenase-2 (COX-2) and PGE₂ production.

Results

Microarray and western blot analyses showed that the mRNA and protein expression of the inflammatory induced microsomal prostaglandin E synthase-1 (mPGES-1) was up-regulated by the cytokine TNFα, accompanied by enhanced expression of COX-2 and increased production of PGE₂. In contrast, the expression of the isoenzymes microsomal prostaglandin E synthase-2 (mPGES-2) and cytosolic prostaglandin E synthase (cPGES) was unaffected by TNFα treatment. Using oligonucleotide microarray analysis in a time-course factorial design including time points 1, 3 and 6 h, differentially expressed genes in response to TNFα treatment were identified. Enrichment analysis of microarray data indicated two positively regulated signal transduction pathways: c-Jun N-terminal kinase (JNK) and Nuclear Factor-κB (NF-κB). To evaluate their involvement in the regulation of mPGES-1 and COX-2 expression, we used specific inhibitors as well as phosphorylation analysis. Phosphorylation analysis of JNK (T183/Y185) and NF-κB p65 (S536) showed increased phosphorylation in response to TNFα treatment, which was decreased by specific inhibitors of JNK (SP600125) and NF-κB (Bay 11-7082, Ro 106-9920). Inhibitors of JNK and NF-κB also decreased the TNFα-stimulated up-regulation of mPGES-1 and COX-2 as well as PGE₂ production.

Conclusion

In the global gene expression profile, the enrichment analysis of microarray data identified the two signal transduction pathways JNK and NF-κB as positively regulated by the cytokine TNFα. Inhibition of these TNFα-activated signal pathways reduced the expression of mPGES-1 and COX-2 as well as their end product PGE₂ in gingival fibroblasts. The involvement of the signal pathways JNK and NF-κB in the regulation of PGE₂ induced by TNFα may suggest these two pathways as possible attractive targets in the chronic inflammatory disease periodontitis.