Proteolytic roles of matrix metalloproteinase (MMP)-13 during progression of chronic periodontitis: initial evidence for MMP-13/MMP-9 activation cascade

NOS3 prevents MMP-9, and MMP-13 induced extracellular matrix proteolytic degradation through specific microRNA-targeted expression of extracellular matrix metalloproteinase inducer in hypertension-related atherosclerosis

BACKGROUND

Endothelial nitric oxide synthase (NOS3) elicits atheroprotection by preventing extracellular matrix (ECM) proteolytic degradation through inhibition of extracellular matrix metalloproteinase inducer (EMMPRIN) and collagenase MMP-13 by still unknown mechanisms.

METHODS

C57BL/6 mice lacking ApoE , NOS3, and/or MMP13 were fed with a high-fat diet for 6 weeks. Entire aortas were extracted and frozen to analyze protein and nucleic acid expression. Atherosclerotic plaques were detected by ultrasound imaging, Oil Red O (ORO) staining, and Western Blot. RNA-seq and RT-qPCR were performed to evaluate EMMPRIN, MMP-9, and EMMPRIN-targeting miRNAs. Mouse aortic endothelial cells (MAEC) were incubated to assess the role of active MMP-13 over MMP-9. One-way ANOVA or Kruskal-Wallis tests were performed to determine statistical differences.

RESULTS

Lack of NOS3 in ApoE null mice fed with a high-fat diet increased severe plaque accumulation, vessel wall widening, and high mortality, along with EMMPRIN-induced expression by upregulation of miRNAs 46a-5p and 486-5p. However, knocking out MMP-13 in ApoE/NOS3 -deficient mice was sufficient to prevent mortality (66.6 vs. 26.6%), plaque progression (23.1 vs. 8.8%), and MMP-9 expression, as confirmed in murine aortic endothelial cell (MAEC) cultures, in which MMP-9 was upregulated by incubation with active recombinant MMP-13, suggesting MMP-9 as a new target of MMP-13 in atherosclerosis.

CONCLUSION

We describe a novel mechanism by which the absence of NOS3 may worsen atherosclerosis through EMMPRIN-induced ECM proteolytic degradation by targeting the expression of miRNAs 146a-5p and 485-5p. Focusing on NOS3 regulation of ECM degradation could be a promising approach in the management of atherosclerosis.

Association Analysis of MMP-13 (rs2252070) Gene Polymorphism and the Susceptibility to Chronic Periodontitis

BACKGROUND

Chronic periodontitis is a multifactorial inflammatory condition influenced by genetic factors. Matrix metalloproteinase (MMP)-13, serving as a crucial enzyme involved in extracellular matrix remodeling, is associated with the degradation of periodontal tissues. Therefore, this study assesses the genetic link between the MMP-13 (rs2252070) genetic variation and chronic periodontitis in a Southern Indian demographic.

METHODOLOGY

The study was conducted at Saveetha Dental College in Chennai, India. It involved a total of 100 subjects, 50 individuals affected with periodontitis (classified as stage II and above, American Association of Periodontology 2018 criteria) and 50 individuals who were periodontally healthy or were diagnosed as having mild gingivitis. We isolated DNA from the blood samples obtained from the participants. Specific primers that flank the BsrI region of the MMP-13 receptor gene were used in the process of DNA amplification. Subsequently, a restriction fragment length analysis using the BsrI enzyme was carried out for genotyping of the amplicon. Based on the restriction fragment length polymorphism pattern, we obtained certain genotypes. These were further recorded and followed by statistical analysis. We conducted a chi-square test to draw a comparison in terms of their genotype and allele frequencies. We calculated the odds ratio, along with 95% confidence intervals.

RESULTS

The frequency of genotypes and distribution of MMP-13 polymorphism did not exhibit a statistically significant difference at χ2 degrees of freedom (P = 0.913). We inferred from our study that there was no significant difference between the groups concerning homozygous and heterozygous mutant genotypes (AA vs. AG + GG), with a P-value of 0.6871. The observed frequencies of GG (47% vs. 43%) and AG+AA (41% vs. 42%) genotypes did not indicate a significant difference between the groups. Similarly, there was no noteworthy distinction between the A allele (62% vs. 65%) and G allele (38% vs. 35%) in the case and control groups.

CONCLUSION

The findings of the study reveal that there is no correlation between MMP-13 (rs2252070) gene polymorphism and periodontitis.

Exploring the Relation Between Interstitial Lung Diseases and Chronic Periodontitis: A Systematic Review

The objective of this systematic review is to determine the association between interstitial lung diseases and chronic periodontitis from various aspects such as microbial, biomarker, genetic, and environmental levels. A systematic review was carried out from 2000 to 2021 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations including studies searched in PubMed-Medline, Google Scholar, and Cochrane databases. A total of more than 100 articles were obtained in the initial screening process. Out of these 42 studies fulfilled the inclusion criteria and were included in the study. According to the extracted data, there is mounting evidence suggesting the association between these two diseases. Our systematic review raises the prospect of a connection between chronic periodontitis and interstitial lung diseases, within the limitations of the studies we included.

Immunomodulatory roles of metalloproteinases in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, autoimmune pathology characterized by persistent synovial inflammation and gradually advancing bone destruction. Matrix metalloproteinases (MMPs), as a family of zinc-containing enzymes, have been found to play an important role in degradation and remodeling of extracellular matrix (ECM). MMPs participate in processes of cell proliferation, migration, inflammation, and cell metabolism. A growing number of persons have paid attention to their function in inflammatory and immune diseases. In this review, the details of regulation of MMPs expression and its expression in RA are summarized. The role of MMPs in ECM remodeling, angiogenesis, oxidative and nitrosative stress, cell migration and invasion, cytokine and chemokine production, PANoptosis and bone destruction in RA disease are discussed. Additionally, the review summarizes clinical trials targeting MMPs in inflammatory disease and discusses the potential of MMP inhibition in the therapeutic context of RA. MMPs may serve as biomarkers for drug response, pathology stratification, and precision medicine to improve clinical management of rheumatoid arthritis.

Increased expression of angiopoietin-like protein 4 regulates matrix metalloproteinase-13 expression in Porphyromonas gingivalis lipopolysaccharides-stimulated gingival fibroblasts and ligature-induced experimental periodontitis

BACKGROUND

Angiopoietin-like protein 4 (ANGPTL4) is produced in chronic or acute inflammation. Although ANGPTL4 increases in the periodontal ligament fibroblasts during hypoxia, the involvement and role of ANGPTL4 in periodontitis have not been elucidated.

OBJECTIVE

In this study, we investigated whether ligature-induced experimental periodontitis and/or Porphyromonas gingivalis lipopolysaccharides (Pg-LPS) would upregulate ANGPTL4 expression and whether ANGPTL4 would somehow involve in the expression of matrix metalloproteinases (MMPs) which are key molecules in the process of periodontal tissue destruction.

METHODS

Experimental periodontitis was induced in 6-week-old male Sprague-Dawley rats by placing a nylon suture around the neck of the maxillary second molar. Two weeks after the induction of periodontitis, the periodontal tissue was excised and analyzed by histological/immunohistochemical staining and gene expression analyses. Human gingival fibroblasts (hGFs) were stimulated with Pg-LPS. The gene expression of ANGPTLs and receptors involved in ANGPTL4 recognition were observed. We also confirmed the changes in gene expression of MMPs upon stimulation with human ANGPTL4. Furthermore, we downregulated ANGPTL4 expression by short interfering RNA in hGFs and investigated the effect of Pg-LPS on MMP production.

RESULTS

Induction of periodontitis significantly increased the expression of ANGPTL4 in the gingiva. Pg-LPS significantly increased the gene and protein expression of ANGPTL4 in hGFs but not the gene expression of other ANGPTLs or ANGPTL receptors. Recombinant human ANGPTL4 significantly increased MMP13 gene expression in hGFs. We also confirmed that MMP13 expression was increased in the gingiva during experimental periodontitis. Pg-LPS induced MMP13 gene expression in hGFs. These results suggest the pivotal role of ANGPTL4 in periodontitis.

CONCLUSION

Periodontitis increases ANGPTL4 expression in the gingiva, further suggesting that increased ANGPTL4 may be a factor involved in enhancing MMP13 expression.

Evaluation of delphinidin as a storage medium for avulsed teeth

BACKGROUND

Delphinidin (DP), an anthocyanidin found in blueberries, has antioxidant and anti-inflammatory effects. This study aimed to investigate the efficacy of DP as a storage medium for avulsed teeth.

METHODS

Human periodontal ligament cells were cultured and exposed to DP solution (10, 50, and 100 μM), Dulbecco's modified Eagle's medium, Hank's balanced salt solution and tap water. Cell counting kit-8 assays were performed after 0.5, 1, 6, and 24 h to measure the cell viability. Nitric oxide assays and gelatin zymography were performed to evaluate the anti-inflammatory effects of DP. Reverse transcription-polymerase chain reaction was used to determine the expression levels of inflammatory cytokines.

RESULTS

The viability of periodontal ligament cells was greatest at 100 μM DP. At 1 h, 100 μM DP decreased nitric oxide synthesis (p < .0167). Matrix metallopeptidase-9 activity was inhibited by DP in a dose-dependent manner (p < .0167). Moreover, treatment with 100 μM DP decreased the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 in periodontal ligament cells (p < .0167).

CONCLUSIONS

Within the limits of this study, DP preserved the viability and suppressed the inflammatory response of periodontal ligament cells. These findings suggest that DP could be promising for preservation of avulsed teeth.

Matrix Metalloproteinase 9 (MMP-9) and Interleukin-8 (IL-8) in Gingival Crevicular Fluid after Regenerative Therapy in Periodontal Intrabony Defects with and without Systemic Antibiotics-Randomized Clinical Trial

The aim of our study was to assess changes in the levels of IL-8 and MMP-9 in gingival crevicular fluid (GCF) collected from the periodontal pocket before and after regenerative surgery with deproteinized bovine bone mineral (DBBM) and collagen membrane (GTR) either independently (DBBM/GTR) or with the postoperative administration of antibiotic (DBBM/GTR+AB). The study involved 41 patients, each with one intrabony defect. IL-8 and MMP-9 were determined before therapy and after 2 weeks, 4 weeks and 6 months following the surgical procedure by means of dedicated ELISA kits. No statistical differences were observed in the levels of IL-8 and MMP-9 after 2 weeks, 4 weeks and 6 months between the groups. The changes in the level of MMP-9 over time were not statistically significant in any group. The changes in the level of IL-8 were significant for the group given antibiotic but not in the nonantibiotic group in the follow-up period. IL-8 and MMP-9 were found to correlate positively but not after 4 weeks in the test group. Current assessment of IL-8 and MMP-9 obtained from GCF samples provides evidence that collagen matrix turnover occurs actively during the early healing phase in the periodontium after regenerative procedures. We observed positive correlations of MMP-9 and IL-8 throughout the study. However, we failed to reveal any differences regard parameters studied between the two groups.

Regulation and Function of Matrix Metalloproteinase-13 in Cancer Progression and Metastasis

Matrix metalloproteinase-13 (MMP-13) is a member of the Matrix metalloproteinases (MMPs) family of endopeptidases. MMP-13 is produced in low amounts and is well-regulated during normal physiological conditions. Its expression and secretion are, however, increased in various cancers, where it plays multiple roles in tumour progression and metastasis. As an interstitial collagenase, MMP-13 can proteolytically cleave not only collagens I, II and III, but also a range of extracellular matrix proteins (ECMs). Its action causes ECM remodelling and often leads to the release of various sequestered growth and angiogenetic factors that promote tumour cell growth, invasion and angiogenesis. This review summarizes our current understanding of the regulation of MMP-13 expression and secretion and discusses the actions of MMP-13 in cancer progression and metastasis.

Oral Microbiome Using Colocasia antiquorum var. esculenta Extract Varnish in a Mouse Model with Oral Gavage of P. gingivalis ATCC 53978

Background and Objective: There is increasing interest in preventing periodontitis using natural products. The purpose of this study was to investigate the effect of Colocasia antiquorum var. esculenta (CA) varnish on the oral microbiome and alveolar bone loss in a mouse periodontitis model. Materials and Methods: Antibacterial activity against Porphyromonas gingivalis (P. gingivalis) ATCC 53978 and cell cytotoxicity using CCK-8 on L929 cells were measured. Balb/c mice were assigned into five groups (negative control, positive control, CA in drinking water, varnish, and CA varnish). P. gingivalis was administered to the mice by oral gavage three times. After sacrifice, the oral microbiome and the levels of the inflammatory cytokine IL-1β and matrix metalloproteinase-9 were analyzed. Alveolar bone loss was measured using micro-computed tomography. Results: CA extract showed an antibacterial effect against P. gingivalis (p < 0.05) and showed no cytotoxicity at that concentration (p > 0.05). Although alpha diversity of the oral microbiome did not statistically differ between the groups (p > 0.05), the relative abundance of dominant bacteria tended to be different between the groups. The inflammatory cytokine IL-1β was reduced in the CA varnish group (p < 0.05), and no difference was observed in MMP-9 expression and alveolar bone loss (p > 0.05). Conclusions: CA varnish did not affect the overall microflora and exhibited an anti-inflammatory effect, suggesting that it is possibility a suitable candidate for improving periodontitis.

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.

Metformin for Cardiovascular Protection, Inflammatory Bowel Disease, Osteoporosis, Periodontitis, Polycystic Ovarian Syndrome, Neurodegeneration, Cancer, Inflammation and Senescence: What Is Next?

Diabetes is accompanied by several complications. Higher prevalence of cancers, cardiovascular diseases, chronic kidney disease (CKD), obesity, osteoporosis, and neurodegenerative diseases has been reported among patients with diabetes. Metformin is the oldest oral antidiabetic drug and can improve coexisting complications of diabetes. Clinical trials and observational studies uncovered that metformin can remarkably prevent or alleviate cardiovascular diseases, obesity, polycystic ovarian syndrome (PCOS), osteoporosis, cancer, periodontitis, neuronal damage and neurodegenerative diseases, inflammation, inflammatory bowel disease (IBD), tuberculosis, and COVID-19. In addition, metformin has been proposed as an antiaging agent. Numerous mechanisms were shown to be involved in the protective effects of metformin. Metformin activates the LKB1/AMPK pathway to interact with several intracellular signaling pathways and molecular mechanisms. The drug modifies the biologic function of NF-κB, PI3K/AKT/mTOR, SIRT1/PGC-1α, NLRP3, ERK, P38 MAPK, Wnt/β-catenin, Nrf2, JNK, and other major molecules in the intracellular signaling network. It also regulates the expression of noncoding RNAs. Thereby, metformin can regulate metabolism, growth, proliferation, inflammation, tumorigenesis, and senescence. Additionally, metformin modulates immune response, autophagy, mitophagy, endoplasmic reticulum (ER) stress, and apoptosis and exerts epigenetic effects. Furthermore, metformin protects against oxidative stress and genomic instability, preserves telomere length, and prevents stem cell exhaustion. In this review, the protective effects of metformin on each disease will be discussed using the results of recent meta-analyses, clinical trials, and observational studies. Thereafter, it will be meticulously explained how metformin reprograms intracellular signaling pathways and alters molecular and cellular interactions to modify the clinical presentations of several diseases.

Spectroscopic molecular-fingerprint profiling of saliva

Saliva analysis has been gaining interest as a potential non-invasive source of disease indicative biomarkers due to being a complex biofluid correlating with blood-based constituents on a molecular level. For saliva to cement its usage for analytical applications, it is paramount to gain underpinning molecular knowledge and establish a 'baseline' of the salivary composition in healthy individuals as well as characterize how these factors are impacting its performance as potential analytical biofluid. Here, we have systematically studied the molecular spectral fingerprint of saliva, including the changes associated with gender, age, and time. Via hybrid artificial neural network algorithms and Raman spectroscopy, we have developed a non-destructive molecular profiling approach enabling the assessment of salivary spectral changes yielding the determination of gender and age of the biofluid source. Our classification algorithm successfully identified the gender and age from saliva with high classification accuracy. Discernible spectral molecular 'barcodes' were subsequently constructed for each class and found to primarily stem from amino acid, protein, and lipid changes in saliva. This unique combination of Raman spectroscopy and advanced machine learning techniques lays the platform for a variety of applications in forensics and biosensing.

Active MMP-8 Quantitative Test as an Adjunctive Tool for Early Diagnosis of Periodontitis

Periodontitis is a host-mediated bacterial disease that affects the tooth attachment apparatus. Metalloproteinase-8 (MMP-8), a validated biomarker, could aid in clinical diagnosis. This study aimed to evaluate the diagnostic performance of active (a) MMP-8 immunotest versus total (t) MMP-8 ELISA for quantitative real-time diagnosis and assessment of periodontitis severity at the site level. Gingival crevicular fluid (GCF) was sampled from 30 healthy, 42 mild, and 59 severe periodontitis sites from thirty-one volunteers. MMP-8 concentrations were determined by time-resolved immunofluorometric assay (IFMA) and enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using the STATA package. Both active and total MMP-8-based methods discriminated among sites according to periodontal diagnosis and severity, with a positive correlation between the two tests (p < 0.001). (a) MMP-8 models showed the best performance in receiver operating characteristic (ROC) curves to discriminate between healthy and periodontitis sites (area under the curve [AUC] = 0.89), while (t) MMP-8 demonstrated a high diagnostic precision in the detection of mild from severe periodontitis sites (AUC ≥ 0.80). The use of (a) MMP-8 and (t) MMP-8 could represent a useful adjunctive tool for periodontitis diagnosis and severity. These results support the applicability of new point-of-care methods in the monitoring of high-risk periodontal patients.

Assessment of Cardiovascular Risk in Women with Periodontal Diseases According to C-reactive Protein Levels

Cardiovascular diseases (CVD) are highly prevalent non-communicable diseases worldwide. Periodontitis may act as a non-traditional cardiovascular risk (CVR) factor, linked by a low-grade systemic inflammation mediated by C-reactive protein (CRP). Patients with periodontitis reported higher serum CRP levels; however, a CRP systemic and periodontal correlation in gingival crevicular fluid (GCF) and its CVR impact have been barely studied. We aimed to assess the association between periodontal diseases and CVR in a group of adult women, based on serum high-sensitivity CRP (hs-CRP) levels; and secondly, to determine the association between serum and GCF CRP levels. Gingival crevicular fluid and blood samples were obtained from women with periodontitis, gingivitis, and healthy controls. Serum and GCF CRP were determined by turbidimetric method and Luminex technology, respectively. Data were analyzed and adjusted by CVR factors. All women presented moderate CVR, without an evident association between serum hs-CRP levels and periodontal diseases. While serum hs-CRP concentrations did not significantly differ between groups, patients with gingivitis and periodontitis showed higher CRP levels in GCF, which positively correlated to CRP detection in serum.

Bacterial adhesion to collagens: implications for biofilm formation and disease progression in the oral cavity

Collagen is the most abundant structural protein in the body and the main component of the extracellular matrix of most tissues, including dentine and periodontal tissues. Despite the well-characterized role of collagen and specifically type-I collagen, as a ligand for host cells, its role as a substrate for bacterial adhesion and biofilm formation is less explored. Therefore, the purpose of this review is to discuss recent findings regarding the adhesion of oral bacteria to collagen surfaces and its role in the progression and severity of oral and systemic diseases. Initial oral colonizers such as streptococci have evolved collagen-binding proteins (cbp) that are important for the colonization of dentine and periodontal tissues. Also, periodontal pathogens such as Porphyromonas gingivalis and Tannerella forsythia utilise cbps for tissue sensing and subsequent invasion. The implications of bacteria-collagen coupling in the context of collagen biomaterials and regenerative dentistry approaches are also addressed. Furthermore, the importance of interdisciplinary techniques such as atomic force microscopy for the nanocharacterization of bacteria-collagen interactions is also considered. Overall, understanding the process of oral bacterial adhesion onto collagen is important for developing future therapeutic approaches against oral and systemic diseases, by modulating the early stages of biofilm formation.

Crucial role of hematopoietic JAK2 V617F in the development of aortic aneurysms

JAK2 V617F is the most frequent driver mutation in myeloproliferative neoplasms (MPN) and is associated with vascular complications. However, the impact of hematopoietic JAK2 V617F on aortic aneurysms (AA) remains unknown. Our cross-sectional study indicated that nine (23%) of 39 MPN patients with JAK2 V617F exhibited the presence of AA. In order to clarify whether the hematopoietic JAK2 V617F contributes to the AA, we applied bone marrow transplantation (BMT) with the donor cells from Jak2 V617F transgenic (JAK2^V617F) mice or control wild-type (WT) mice into lethally irradiated apolipoprotein E-deficient mice. Five weeks after BMT, the JAK2^V617F-BMT mice and WT-BMT mice were subjected to continuous angiotensin II infusion to induce AA formation. Four weeks after angiotensin II infusion, the abdominal aorta diameter in the JAK2^V617F-BMT mice was significantly enlarged compared to that in the WT-BMT mice. Additionally, the abdominal AA-free survival rate was significantly lower in the JAK2^V617F-BMT mice. Hematopoietic JAK2 V617F accelerated aortic elastic lamina degradation as well as activation of matrix metalloproteinase (MMP)-2 and MMP-9 in the abdominal aorta. The numbers of infiltrated macrophages were significantly upregulated in the abdominal aorta of the JAK2^V617F-BMT mice accompanied by STAT3 phosphorylation. The accumulation of BM-derived hematopoietic cells carrying JAK2 V617F in the abdominal aorta was confirmed by use of the reporter green fluorescent proteintransgene. BM-derived macrophages carrying JAK2 V617F showed increases in mRNA expression levels of Mmp2, Mmp9, and Mmp13. Ruxolitinib decreased the abdominal aorta diameter and the incidence of abdominal AA in the JAK2^V617F-BMT mice. Our findings provide a novel feature of vascular complications of AA in MPN with JAK2 V617F.

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

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

[The significance of the expression of matrix metalloproteinases in the differential diagnosis of periodontal diseases]

Investigation of features of expression of matrix metalloproteinases (MMPs) is important for both understanding the mechanisms of the pathogenesis of periodontal diseases, and determining the nature of their course in order to choose a correct and timely treatment strategy.

OBJECTIVE

To establish the value of MMPs for the diagnosis and determination of the nature of the course of periodontitis at the stage of disease manifestation, by morphometrically assessing the expression of MMPs in the gingival biopsy material.

MATERIAL AND METHODS

Gingival biopsy specimens from 82 patients with rapidly progressing (n=26), chronic simple (n=18), and chronic complex (n=38) periodontitis were analyzed. Morphometric and statistical analysis of the expression of MMPs was carried out using Aperio ImageScope v. 12.4.0.5043, Statistica 10.0, and MedCalc (p<0.05).

RESULTS

Analysis of the nature of MMP expression in the gingival biopsy material of patients with periodontal diseases showed that MMP2 and MMP13 were approximately equally involved in the development and course of all the studied forms of periodontitis. An increase in the expression of MMP1, MMP8, and MMP14 and a decrease in that of MMP9 are of the greatest importance in the pathogenesis of a rapidly progressing process. The performed ROC analysis confirmed the significance of the parameters of general and stromal expression of MMP1, MMP9, and MMP14, and mainly stromal expression of MMP8 for the differential diagnosis of rapidly progressing periodontitis with chronic forms, including chronic complex periodontitis.

CONCLUSION

The expression indicators of MMR1, MMR8, MMR9, and MMR14 are most informative in determining the course of periodontitis at the stage of disease manifestation and differential diagnosis of rapidly progressing periodontitis with chronic simplex and complex periodontitis.

Effect of Subantimicrobial Dose Doxycycline Treatment on Gingival Crevicular Fluid Levels of MMP-9 and MMP-13 in Periodontitis Stage 2, Grade B in Subjects with Type 2 Diabetes Mellitus

The aim of this study was to investigate the effect of using subantimicrobial dose doxycycline as an adjunct in periodontitis stage 2, grade B in subjects with type 2 diabetes mellitus. A total of thirty patients were divided into the following two groups with reference to periodontitis, type 2 diabetes mellitus, and administration of the doxycycline drug: Group I: patients with periodontitis stage 2, grade B and type 2 diabetes mellitus who received SRP only. Group II: patients with periodontitis stage 2, grade B and type 2 diabetes mellitus who received SRP and doxycycline 20 mg. The following clinical measurements were recorded at baseline (prior to scaling and root planning) and after one and three months postoperatively: GI, PI, and PD with a periodontal calibrated probe. The levels of both MMP-9 and MMP-13, from 60 GCF samples, were analyzed by ELISA. Patients treated with SRP and doxycycline 20 mg showed a significant reduction of PD, PI, GI, MMP-9, and MMP-13 than patients who received SRP only. Improvements in parameters clinically and biochemically were observed following the adjunctive use of doxycycline subantimicrobial dose therapy for the management of stage 2, grade B periodontitis patients with type 2 diabetes mellitus.

Silencing matrix metalloproteinase-13 (Mmp-13) reduces inflammatory bone resorption associated with LPS-induced periodontal disease in vivo

OBJECTIVES

The aim of this study was to evaluate the effect of specific inhibition of MMP-13 on inflammation and inflammatory bone resorption in a murine model of lipopolysaccharide (LPS)-induced periodontitis.

MATERIALS AND METHODS

Periodontitis was induced in mice by micro-injections of LPS into the gingival tissues adjacent to the palatal surfaces of maxillary molars twice a week for 15 days. Matrix metalloproteinase-13 (Mmp-13) shRNA or a specific biochemical inhibitor were also injected into the same sites in alternating days with the LPS injections. Efficacy of shRNA-mediated silencing of Mmp-13 was verified by quantitative real-time polymerase chain reaction (qPCR) and immunoblot. Bone resorption was assessed by microcomputed tomography (uCT). Histological sections stained with hematoxylin/eosin (H/E) were used in the stereometric analysis of the inflammatory infiltrate. Gingival tissues were used to evaluate expression of Mmp-13, Il-6, Tnf-α, Ptgs2, and Rankl (qPCR). Protein levels of TGF-β and IL-10 in the tissues were determined by enzyme-linked immunosorbent assays (ELISA) or by MMP-13 and p38 immunoblot.

RESULTS

Silencing Mmp-13 expression reduced bone resorption significantly. Expression of Mmp-13, Il-6, and Tnf-α, as well as the protein levels of IL-6 and TNF-α, was reduced in the animals treated with adenovirus-delivered shRNA; however, these effects were not associated with modulation of p38 MAPK signaling. Interestingly, inhibition Mmp-13 did not affect the severity of inflammatory infiltrate.

CONCLUSIONS

Site-specific inhibition of MMP-13 reduced bone resorption and production of inflammatory mediators associated with periodontal disease.

CLINICAL RELEVANCE

The results suggest that site-specific inhibition of MMP-13 may be an interesting strategy to modulate inflammation and reduce bone resorption in osteolytic inflammatory diseases.

MMP-8, TRAP-5, and OPG Levels in GCF Diagnostic Potential to Discriminate between Healthy Patients', Mild and Severe Periodontitis Sites

Biomarkers represent promising aids in periodontitis, host-mediate diseases of the tooth-supporting tissues. We assessed the diagnostic potential of matrix metalloproteinase-8 (MMP-8), tartrate-resistant acid phosphatase-5 (TRAP-5), and osteoprotegerin (OPG) to discriminate between healthy patients’, mild and severe periodontitis sites. Thirty-one otherwise healthy volunteers with and without periodontal disease were enrolled at the Faculty of Dentistry, University of Chile. Periodontal parameters were examined and gingival crevicular fluid was sampled from mild periodontitis sites (M; n = 42), severe periodontitis sites (S; n = 59), and healthy volunteer sites (H; n = 30). TRAP-5 and OPG were determined by commercial multiplex assay and MMP-8 by the immunofluorometric (IFMA) method. STATA software was used. All biomarkers showed a good discrimination performance. MMP-8 had the overall best performance in regression models and Receiver Operating Characteristic (ROC) curves, with high discrimination of healthy from periodontitis sites (area under the curve (AUC) = 0.901). OPG showed a very high diagnostic precision (AUC ≥ 0.95) to identify severe periodontitis sites (S versus H + M), while TRAP-5 identified both healthy and severe sites. As conclusions, MMP-8, TRAP-5, and OPG present a high precision potential in the identification of periodontal disease destruction, with MMP-8 as the most accurate diagnostic biomarker.

Drug-Induced Gingival Overgrowth: The Effect of Cyclosporin A and Mycophenolate Mophetil on Human Gingival Fibroblasts

Drug-induced gingival overgrowth may occur after a chronic administration of three classes of systemic drugs: Anticonvulsants, immunosuppressants, and calcium channel blockers. This study aimed to investigate how cyclosporin A and mycophenolate mophetil (immunosuppressive drugs) could interfere with human gingival fibroblasts functions, leading to gingival enlargement. Human gingival fibroblasts derived from the tissue of a 60-year-old female were cultured in a DMEME medium. A stock solution with 1 mg/mL of mycophenolate and 1 mg/mL of cyclosporine were prepared and dissolved in a DMEM medium to prepare a serial dilution at the concentrations of 5000, 2000, 1000, 500, and 100 ng/mL, for both treatments. Cell viability was measured using the PrestoBlue™ Reagent Protocol. Quantitative real-time RT-PCR was performed in order to analyze the expression of 57 genes coding for gingival fibroblasts "Extracellular Matrix and Adhesion Molecules". Mycophenolate and cyclosporine had no effect on fibroblast cell viability at 1000 ng/mL. Both the treatments showed similar effects on the expression profiling of treated cells: Downregulation of most extracellular matrix metalloproteases genes (MMP8, MMP11, MMP15, MMP16, MMP24) was assessed, while CDH1, ITGA2, ITGA7, LAMB3, MMP12, and MMP13 were recorded to be upregulated in fibroblasts treated with immunosuppressive drugs. It has been demonstrated that gingival overgrowth can be caused by the chronic administration of cyclosporin A and mycophenolate mophetil. However, given the contrasting data of literature, further investigations are needed, making clear the possible effects of immunosuppressive drugs on fibroblasts.

Polymeric Carriers for Delivery Systems in the Treatment of Chronic Periodontal Disease

Periodontitis (PD) is a chronic inflammatory disease of periodontal tissues caused by pathogenic microorganisms and characterized by disruption of the tooth-supporting structures. Conventional drug administration pathways in periodontal disease treatment have many drawbacks such as poor biodistribution, low selectivity of the therapeutic effect, burst release of the drug, and damage to healthy cells. To overcome this limitation, controlled drug delivery systems have been developed as a potential method to address oral infectious disease ailments. The use of drug delivery devices proves to be an excellent auxiliary method in improving the quality and effectiveness in periodontitis treatment, which includes inaccessible periodontal pockets. This review explores the current state of knowledge regarding the applications of various polymer-based delivery systems such as hydrogels, liposomes, micro-, and nanoparticles in the treatment of chronic periodontal disease. Furthermore, to present a more comprehensive understanding of the difficulties concerning the treatment of PD, a brief description of the mechanism and development of the disease is outlined.

The Role of Matrix Metalloproteinases in Periodontal Disease

This review provides a detailed description of matrix metalloproteinases (MMPs), focusing on those that are known to have critical roles in bone and periodontal disease. Periodontal disease is an inflammatory process initiated by anaerobic bacteria, which promote the host immune response in the form of a complex network of molecular pathways involving proinflammatory mediators such as cytokines, growth factors, and MMPs. MMPs are a family of 23 endopeptidases, collectively capable of degrading virtually all extracellular matrix (ECM) components. This study critically discusses the available research concerning the involvement of the MMPs in periodontal disease development and progression and presents possible therapeutic strategies. MMPs participate in morphogenesis, physiological tissue turnover, and pathological tissue destruction. Alterations in the regulation of MMP activity are implicated in the manifestation of oral diseases, and MMPs comprise the most important pathway in tissue destruction associated with periodontal disease. MMPs can be considered a risk factor for periodontal disease, and measurements of MMP levels may be useful markers for early detection of periodontitis and as a tool to assess prognostic follow-ups. Detection and inhibition of MMPs could, therefore, be useful in periodontal disease prevention or be an essential part of periodontal disease therapy, which, considering the huge incidence of the disease, may greatly improve oral health globally.

Effects of estrogen deficiency followed by streptozotocin-induced diabetes on periodontal tissues of female rats

Although both estrogen deficiency and diabetes contribute to periodontal tissue deterioration, the combined effects of these conditions on periodontium is unknown. Thus, we analyzed the combined effects of ovariectomy followed by streptozotocin (STZ)-induced diabetes on periodontal tissues of rats. Twenty adult rats were ovariectomized (OVX) or SHAM-operated (SHAM). After 3 weeks, the rats received an intraperitoneal injection of STZ (60 mg/kg/body weight) to induce diabetes or vehicle (blank) solution. The groups were assigned as follows (n = 5): SHAM-vehicle (SHAM), OVX-vehicle (OVX), SHAM + STZ (SHAM-Di), and OVX + STZ (OVX-Di). Seven weeks post-diabetes induction, the rats were euthanized. Blood samples were collected for glucose measurements and maxillae were processed for paraffin embedding. Sections stained with hematoxylin/eosin, Masson's trichrome, and picrosirius-red were used for alveolar bone loss and collagen fiber analysis in the lamina propria. Immunohistochemistry was performed for runt-related transcription factor 2 (Runx2), matrix metalloproteinase 9 (MMP-9), and tryptase detection. Alveolar bone loss and fewer collagen fibers were observed in the OVX-Di group, collagen fibers with irregular organization, and MMP-9 immunoreactivity were more evident in diabetic groups, and MMP-9-positive osteoclasts on alveolar bone surface were noticed in all groups. The OVX-Di group showed lower Runx2 immunoreactivity (osteoblast formation marker), and more tryptase-positive cells (mast cell marker) in the alveolar bone marrow. Our results indicate that estrogen depletion, followed by STZ-induced diabetes, promotes periodontal tissue deterioration that is more evident than both interventions applied alone. Furthermore, our results points to a possible participation of bone-derived mast cells in this process.

Calcitriol inhibits osteoclastogenesis in an inflammatory environment by changing the proportion and function of T helper cell subsets (Th2/Th17)

Objectives

Previously, we found that by regulating T helper (Th) cell polarization, calcitriol intervention inhibited lipopolysaccharide (LPS)‐induced alveolar bone loss in an animal periodontitis model, but the underlying cellular events remain unknown.

Materials and methods

In this study, mouse Th cells were incubated in an inflammatory environment in the presence of dendritic cells (DCs) and LPS. Then, the potential of the Th cells to undergo Th2/Th17 polarization, the RANKL expression of the polarized Th cells and the subsequent influences of the polarized Th cells on RAW264.7 cell osteoclastogenesis in response to calcitriol administration were assessed. Finally, the effects of calcitriol on antigen presentation by DCs during these cellular events were evaluated.

Results

In response to calcitriol administration, Th cells in an inflammatory environment exhibited an enhanced potential for Th2 polarization along with a decreased potential for Th17 polarization. In addition, RANKL expression in Th17‐polarized cells was largely inhibited. Furthermore, inflammation‐induced osteoclastogenesis in RAW264.7 cells was suppressed following coculture with calcitriol‐treated Th cells. During these cellular events, increased expression of Th2 promoters (such as OX‐40L and CCL17) and decreased expression of Th17 promoters (such as IL‐23 and IL‐6) were found in DCs.

Conclusions

Calcitriol can inhibit osteoclastogenesis in an inflammatory environment by changing the proportion and function of Th cell subsets. Our findings suggest that calcitriol may be an effective therapeutic agent for treating periodontitis.

Developing a periodontal disease antibody array for the prediction of severe periodontal disease using machine learning classifiers

BACKGROUND

The aim of this study was to simultaneously and quantitatively assess the expression levels of 20 periodontal disease-related proteins in gingival crevicular fluid (GCF) from normal controls (NOR) and severe periodontitis (SP) patients with an antibody array.

METHODS

Antibodies against 20 periodontal disease-related proteins were spotted onto a glass slide to create a periodontal disease antibody array (PDD). The array was then incubated with GCF samples collected from 25 NOR and 25 SP patients. Differentially expressed proteins between NOR and SP patients were then used to build receiver operator characteristic (ROC) curves and compare five classification models, including support vector machine, random forest, k nearest neighbor, linear discriminant analysis, and Classification and Regression Trees.

RESULTS

Seven proteins (C-reactive protein, interleukin [IL]-1α, interleukin-1β, interleukin-8, matrix metalloproteinase-13, osteoprotegerin, and osteoactivin) were significantly upregulated in SP patients compared with NOR, while receptor activator of nuclear factor-kappa was significantly downregulated. The highest diagnostic accuracy using a ROC curve was observed for IL-1β with an area under the curve of 0.984. Five of the proteins (IL-1β, IL-8, MMP-13, osteoprotegerin, and osteoactivin) were identified as important features for classification. Linear discriminant analysis had the highest classification accuracy across the five classification models that were tested.

CONCLUSION

This study highlights the potential of antibody arrays to diagnose periodontal disease.

Adjunctive Effects of a Sub-Antimicrobial Dose of Doxycycline on Clinical Parameters and Potential Biomarkers of Periodontal Tissue Catabolism

Objectives: The aim of the present randomized, double-blind, placebo-controlled, parallel-arm study was to examine the effectiveness of a sub-antimicrobial dose of doxycycline (SDD) in combination with nonsurgical periodontal therapy, compared to nonsurgical periodontal therapy alone, on potential gingival crevicular fluid (GCF) biomarkers of periodontal tissue catabolism related to the clinical outcomes over a 12-month period. Materials and Methods: GCF was collected and clinical parameters were recorded from 30 periodontitis patients randomized either to an SDD or placebo group. The SDD group received SDD (20 mg) b.i.d for 3 months plus scaling and root planing (SRP), while the placebo group was given placebo capsules b.i.d for 3 months plus SRP. The patients were evaluated every 3 months during the 12-month study period. At each visit, clinical parameters and GCF sampling were repeated. Matrix metalloproteinase (MMP)-8, MMP-9, MMP-13, myeloperoxidase (MPO), osteoprotegerin (OPG), and tartrate-resistant acid phosphatase-5 (TRAP-5) were determined by IFMA and ELISA. Results: Significant improvements were observed in all clinical parameters in both groups over 12 months (p < 0.0125) while the SDD group showed significantly better reduction in gingival index (GI) and pocket depth and a gain in clinical attachment compared to the placebo group (p < 0.05). GCF MMP-8 and OPG levels significantly reduced in the SDD group compared to baseline (p < 0.05). GCF MMP-9 significantly decreased in both groups compared to baseline (p < 0.05). GCF MPO significantly decreased at 3 and 9 months in the SDD group, while it significantly decreased at 6 months in the placebo group (p < 0.05). TRAP and MMP-13 could be detected in none of the samples. Conclusions: The present results indicate that three months of adjunctive usage of SDD to nonsurgical periodontal therapy compared to nonsurgical periodontal therapy alone in periodontitis patients results in further improvement of clinical periodontal parameters and GCF markers of periodontal tissue breakdown over a 12-month period. Beneficial effects of adjunctive SDD therapy is likely to be related to the reduced levels of two major periodontitis-associated MMPs, MMP-8 and -9, and their potential oxidative activator MPO.

MiRNA-218 regulates osteoclast differentiation and inflammation response in periodontitis rats through Mmp9

Periodontitis is a multiple infection and inflammatory disease featured by connective tissue homeostasis loss, periodontal inflammation, and alveolar bone resorption. MicroRNAs (miRNAs) are involved in the mediation of a large scale of pathological processes. Here, we show that miRNA-218 provides protective effect on periodontitis via regulation of matrix metalloproteinase-9 (Mmp9). This pathway is aberrant in periodontium from rats with periodontitis and human periodontal ligament progenitor cells stimulated by lipopolysaccharide, with downregulation of miR-218 and higher levels of Mmp9 compared with periodontium from healthy rats and cells without stimulation. Overexpression of miR-218 can suppress the degradation of Collagen Types I and IV and dentin sialoprotein (DSP), attenuate osteoclast formation, and inhibit the secretion of proinflammatory cytokines. On the other hand, overexpression of Mmp9 promotes the degradation of Collagen Types I and IV and DSP as well as RANKL-induced osteoclast formation and elevates inflammatory factors levels. Furthermore, the inhibitory effect of miR-218 was prevented by rescuing the Mmp9 expression. In addition, we also have showed that miR-218 was able to attenuate bone resorption and inflammation in a periodontitis rat model. Collectively, our findings therefore suggest that miR-218 acts as a protective role in periodontitis through the regulation of Mmp9.

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

Context:

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

Aims:

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

Settings and Design:

This was an observational case–control study.

Materials and Methods:

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

Statistical Analysis Used:

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

Results:

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

Conclusion:

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

Matrix metalloproteinases in pro-atherosclerotic arterial remodeling

Matrix metalloproteinases (MMPs) is a family of Zn²⁺ endopeptidases that process various components of the extracellular matrix. These enzymes are also involved in activation and inhibition of signaling cascades through proteolytic cleavage of surface receptors. Moreover, MMPs play a key role in tissue remodeling and and repair. Dysregulation of MMPs is observed in patholofgical conditions, including atherosclerosis, which is associated with hyperactivation of MMPs, aberrant tissue remodeling and neovascularization of the growing atherosclerotic plaques. This makes MMPs interesting therapeutic targets that can be employed for developing novel therapies to treat atherosclerosis and its complications. Currently, a growing number of synthetic MMP inhibitors is available. In this review, we will discuss the role of these enzymes in atherosclerosis pathology and the ways of their pothential therapeutic use.

Oxidative Stress in the Local and Systemic Events of Apical Periodontitis

Oxidative stress is involved in the pathogenesis of a variety of inflammatory disorders. Apical periodontitis (AP) usually results in the formation of an osteolytic apical lesion (AL) caused by the immune response to endodontic infection. Reactive oxygen species (ROS) produced by phagocytic cells in response to bacterial challenge represent an important host defense mechanism, but disturbed redox balance results in tissue injury. This mini review focuses on the role of oxidative stress in the local and associated systemic events in chronic apical periodontitis. During endodontic infection, ligation of Toll-like receptors (TLRs) on phagocytes' surface triggers activation, phagocytosis, synthesis of ROS, activation of humoral and cellular responses, and production of inflammatory mediators, such as, cytokines and matrix metalloproteinases (MMPs). The increment in ROS perturbs the normal redox balance and shifts cells into a state of oxidative stress. ROS induce molecular damage and disturbed redox signaling, that result in the loss of bone homeostasis, increased pro-inflammatory mediators, and MMP overexpression and activation, leading to apical tissue breakdown. On the other hand, oxidative stress has been strongly involved in the pathogenesis of atherosclerosis, where a chronic inflammatory process develops in the arterial wall. Chronic AP is associated with an increased risk of cardiovascular diseases (CVD) and especially atherogenesis. The potential mechanisms linking these diseases are also discussed.

Salivary MMP-13 gender differences in periodontitis: A cross-sectional study from Sweden

We investigated serum and saliva concentrations of matrix metalloproteinases, MMP-8, MMP-9, and MMP-13, and their tissue inhibitor TIMP-1, in a group of patients with and without periodontitis from Sweden. The hypothesis was that these biomarkers are higher in the periodontitis patients. Ninety patients participated in this cross-sectional study. Fifty-one patients had periodontitis whereas 39 were periodontally healthy. Saliva and serum samples were analyzed with immunofluorometric, enzyme-linked immunosorbent assay and western blot. Results were statistically analyzed with independent t test, Mann-Whitney U test, Bonferroni corrections, and regression analyses. MMP-13 was not detected in serum, but in saliva, higher values were found among the periodontally healthy compared with periodontitis subjects (0.32 ± 0.26 vs. 0.21 ± 0.23 ng/ml, p < .05). Female gender and clinical attachment loss were the explanatory factors for higher salivary MMP-13 values with odds ratio 3.08 (95% confidence interval [1.17, 8.11]) and 3.57 (95% confidence interval [1.08, 11.82]), respectively. No statistically significant differences between groups were found in serum and saliva values of MMP-8, MMP-9, and TIMP-1. Contrary to our hypothesis, no statistically significant differences between patients with and without periodontitis were seen in MMP-8, MMP-9, and TIMP-1 values. However, higher MMP-13 concentrations in saliva were associated with female gender and higher clinical attachment loss. Metabolism of MMP-13 may thus have some gender implications in periodontitis.

Zoledronate Impairs Socket Healing after Extraction of Teeth with Experimental Periodontitis

Osteonecrosis of the jaws (ONJ) is a rare but severe complication of antiresorptive medications, such as bisphosphonates, used in the treatment of bone malignancy or osteoporosis. Tooth extraction and dental disease have been strongly associated with ONJ development. Here, we investigated molecular and cellular markers of socket healing after extraction of healthy or teeth with experimental periodontitis (EP) in Wistar-Han rats treated with zoledronic acid (ZA). We included 4 experimental groups: vehicle-treated animals with extraction of healthy teeth or teeth with ligature-induced EP and ZA-treated animals with extraction of healthy teeth or teeth with EP. Animals were pretreated with vehicle or ZA for a week, and EP was induced. Four weeks later, the second maxillary molars were extracted; sockets were allowed to heal for 4 wk; animals were euthanized; and maxillae were isolated. Radiographically, extraction sockets in groups 1, 2, and 3 demonstrated normal healing. Contrary incomplete socket healing was noted after extraction of teeth with EP in ZA-treated rats of group 4. Histologically, persistent inflammation and extensive osteonecrosis were seen in group 4. Disorganization of the collagen network, collagen type III predominance, and lack of collagen fiber insertion in the necrotic bone were associated with impaired socket healing. Cells positive for MMP-9, MMP-13, and α-SMA expression were present at the areas of epithelial invagination and adjacent to osteonecrotic bone. Importantly, human biopsies from patients with ONJ showed similar findings. Our data emphasize the importance of dental disease and tooth extraction in ONJ pathogenesis and help delineate an altered profile in wound-healing markers during ONJ development.

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.

CXCL10 suppression of hem- and lymph-angiogenesis in inflamed corneas through MMP13

Though not present in the normal adult cornea, both hem- and lymph-angiogenesis can be induced in this tissue after an inflammatory, infectious, or traumatic insult. We previously showed that the chemokine CXCL10 plays a key role in eradicating invading Candida (C.) albicans in C57BL6 mouse corneas. However, even after the clearance of pathogens, infection-induced inflammation and angiogenesis continue to progress in the cornea. The aim of this study is define the role of CXCL10 as a major angiostatic factor in modulating cornea angiogenesis in B6 mouse corneas under pathogenic conditions. We showed that epithelial expression of CXCL10, driven by AAV9 vector, suppressed both infection- and inflammation-induced hem and lymph angiogenesis, whereas the neutralization of CXCL10 as well as its receptor CXCR3 greatly promoted these processes. The inhibitory effect of CXCL10 was unrelated to its antimicrobial activity, but through the suppression of the expression of many angiogenic factors, including VEGFa and c, and MMP-13 in vivo. Inhibition of MMP13 but not TIMPs, attenuated suture-induced neovascularization but had no effects on CXCL10 expression. Strikingly, topical application of CXCL10 post-C. albicans infection effectively blocked both hem- and lymph-angiogenesis and preserved the integrity of sensory nerves in the cornea. Taken together, CXCL10 has strong inhibitory effects on neovascularization, whereas MMP13 is required for neovascularization in C. albicans-infected corneas and the local application of CXCL10 or MMP13 inhibitors, alone or as adjuvant therapy, may target hem- and lymph-angiogenesis in the inflamed corneas.

Matrix Metalloproteinases as Regulators of Periodontal Inflammation

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

Mucin 4 and matrix metalloproteinase 7 as novel salivary biomarkers for periodontitis

AIM

Periodontitis is a chronic inflammatory disease, characterized by irreversible destruction of tooth-supporting tissue including alveolar bone. We recently reported mucin 4 (MUC4) and matrix metalloproteinase 7 (MMP7) as highly associated with periodontitis in gingival tissue biopsies. The aim of this study was to further investigate the levels of MUC4 and MMP7 in saliva and gingival crevicular fluid (GCF) samples of patients with periodontitis.

MATERIALS AND METHODS

Saliva and GCF samples were collected from periodontitis patients and healthy controls. The levels of MUC4, MMP7, and total protein concentrations were analysed using ELISA or Bradford assay.

RESULTS

MUC4 levels were significantly lower in saliva and GCF from periodontitis patients relative to healthy controls. MMP7 levels were significantly higher in saliva and GCF from periodontitis patients. Multivariate analysis revealed that MUC4 was significantly associated with periodontitis after adjusting for age and smoking habits and, moreover, that the combination of MUC4 and MMP7 accurately discriminated periodontitis from healthy controls.

CONCLUSIONS

MUC4 and MMP7 may be utilized as possible novel biomarkers for periodontitis.

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.

Oxidized LDL-Exposed Human Macrophages Display Increased MMP-9 Expression and Secretion Mediated by Endoplasmic Reticulum Stress

Oxidatively modified low-density lipoproteins (oxLDL) alter the proper function of the endoplasmic reticulum (ER), inducing ER stress (ERS), which consequently activates inflammatory pathways in macrophages. Matrix metalloproteinase-9 (MMP-9) is the main protease acting on the degradation of the extracellular matrix and the ensuing destabilization of the atherosclerotic plaque. We aimed to investigate whether ERS induced by oxLDL or tunicamycin (TM) in human macrophages is associated with the stimulation of MMP-9 expression and secretion. The results showed that oxLDL induced in THP-1 macrophages: (i) increase of MMP-9 gene expression and its pro-form secretion, (ii) intracellular accumulation of 7-ketocholesterol, (iii) ERS activation (increased eIF2α phosphorylation, XBP1 and CHOP mRNA levels, and Grp78 protein expression), and (iv) oxidative stress (increased levels of reactive oxygen species and NADPH oxidase activity). Incubation of macrophages with ERS inducer, TM determined the secretion of both pro- and active-form of MMP-9 and oxidative stress. Treatment of oxLDL or TM-incubated cells with ERS inhibitor, sodium phenylbutyrate decreased MMP-9 gene expression, secretion, and activity. The inhibitor of NADPH oxidase, apocynin, decreased XBP-1 and CHOP mRNA levels, and MMP-9 gene expression and secretion in oxLDL-exposed cells. In conclusion, oxLDL stimulate MMP-9 expression and secretion in human macrophages by mechanisms involving ERS. J. Cell. Biochem. 118: 661-669, 2017. © 2016 Wiley Periodicals, Inc.

Trivalent metal ions based on inorganic compounds with in vitro inhibitory activity of matrix metalloproteinase 13

Collagenase-3 (MMP-13) inhibitors have attracted considerable attention in recent years and have been developed as a therapeutic target for a variety of diseases, including cancer. Matrix metalloproteinases (MMPs) can be inhibited by a multitude of compounds, including hydroxamic acids. Studies have shown that materials and compounds containing trivalent metal ions, particularly potassium hexacyanoferrate (III) (K3[Fe(CN)6]), exhibit cdMMP-13 inhibitory potential with a half maximal inhibitory concentration (IC50) of 1.3μM. The target protein was obtained by refolding the recombinant histidine-tagged cdMMP-13 using size exclusion chromatography (SEC). The secondary structures of the refolded cdMMP-13 with or without metal ions were further analyzed via circular dichroism and the results indicate that upon binding with metal ions, an altered structure with increased domain stability was obtained. Furthermore, isothermal titration calorimetry (ITC) experiments demonstrated that K3[Fe(CN)6]is able to bind to MMP-13 and endothelial cell tube formation tests provide further evidence for this interaction to exhibit anti-angiogenesis potential. To the best of our knowledge, no previous report of an inorganic compound featuring a MMP-13 inhibitory activity has ever been reported in the literature. Our results demonstrate that K3[Fe(CN)6] is useful as a new effective and specific inhibitor for cdMMP-13 which may be of great potential for future drug screening applications.

Potential Role of Reversion-Inducing Cysteine-Rich Protein with Kazal Motifs (RECK) in Regulation of Matrix Metalloproteinases (MMPs) Expression in Periodontal Diseases

Periodontal diseases are characterized by pathological destruction of extracellular matrix (ECM) of periodontal tissues. Matrix metalloproteinases (MMPs) are a significant part of the degradation of ECM. However, the regulation of MMPs expression level in periodontal diseases is as yet undetermined.

RECK (reversion-inducing cysteine-rich protein with Kazal motifs), a novel membrane-anchored inhibitor of MMPs, could regulate the expressions of MMP-2, 9 and MT1-MMP as a cell surface-signaling molecule. Thus, we propose that RECK may play an important role in regulating MMPs in the ECM degradation of periodontal diseases. The RECK/MMPs signaling pathway could provide a new approach for prevention and treatment of RECK in periodontal diseases by blocking MMPs.

Host response mechanisms in periodontal diseases

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

Immunohistochemical localisation and effect of matrix metalloproteinases and their inhibitors on canine spontaneous periodontitis

Periodontitis is commonly observed in dogs. In human medicine, it is well documented that matrix metalloproteinases (MMPs) are involved in the destruction of the periodontium. Therefore, the aim of this prospective study was to investigate the impact of MMPs and their inhibitors, the TIMPs (tissue inhibitors of metalloproteinases), on canine periodontitis. The oral cavities of 57 dogs were examined clinically and radiologically. Gingival biopsies were obtained from the examined dogs and histologically analysed via haematoxylin and eosin stained sections. Immunohistological detection of MMP-2, MMP-3, MMP-8 and MMP-9 as well as TIMP-1 and TIMP-2 was performed by the avidin-biotin peroxidase complex technique. All sections were evaluated by light microscopy. Statistically significant positive correlations were detected between the histologically verified degree of inflammation and the expression of MMP-2, MMP-3, MMP-8 and MMP-9 as well as between changes in collagen fibre content and the occurrence of MMP-2, MMP-8 and MMP-9. Concerning TIMP-1 and TIMP-2, non-significant, generally negative correlations were observed. In summary, in canine periodontitis, an increased expression of the above mentioned MMPs and a tendentially decreased expression of TIMPs are present. In conclusion, in canine periodontitis, a MMP-TIMP imbalance is suggestive of contributing to the destruction of the periodontium.

Hox10-regulated endodermal cell migration is essential for development of the ascidian intestine

Hox cluster genes play crucial roles in development of the metazoan antero-posterior axis. Functions of Hox genes in patterning the central nervous system and limb buds are well known. They are also expressed in chordate endodermal tissues, where their roles in endodermal development are still poorly understood. In the invertebrate chordate, Ciona intestinalis, endodermal tissues are in a premature state during the larval stage, and they differentiate into the digestive tract during metamorphosis. In this study, we showed that disruption of a Hox gene, Ci-Hox10, prevented intestinal formation. Ci-Hox10-knock-down larvae displayed defective migration of endodermal strand cells. Formation of a protrusion, which is important for cell migration, was disrupted in these cells. The collagen type IX gene is a downstream target of Ci-Hox10, and is negatively regulated by Ci-Hox10 and a matrix metalloproteinase ortholog, prior to endodermal cell migration. Inhibition of this regulation prevented cellular migration. These results suggest that Ci-Hox10 regulates endodermal strand cell migration by forming a protrusion and by reconstructing the extracellular matrix.