Involvement of MT1-MMP and TIMP-2 in human periodontal disease

Diagnostic potential and future directions of matrix metalloproteinases as biomarkers in gingival crevicular fluid of oral and systemic diseases

Gingival crevicular fluid (GCF) is a physiological fluid and an inflammatory serum exudate derived from the gingival plexus of blood vessels and mixed with host tissues and subgingival plaque flows. In addition to proteins, GCF contains a diverse population of cells, including desquamated epithelial cells, cytokines, electrolytes, and bacteria from adjacent plaques. Recently, matrix metalloproteinases(MMPs), which are endopeptidases that are active against extracellular macromolecules, in GCF have been revealed as potential utility biomarkers for the diagnosis and follow-up of oral and systemic diseases, thereby facilitating the early evaluation of malignancy risk and the monitoring of disease progression and treatment response. Tissue inhibitors of metalloproteinases (TIMPs) are specific inhibitors of matrixins that participate in the regulation of local activities of MMPs in tissues. This review provides an overview of the latest findings on the diagnostic and prognostic values of MMPs and TIMPs in GCF of oral and systemic diseases, including periodontal disease, pulpitis, peri-implantitis and cardiovascular disease as well as the extraction, detection and analytical methods for GCF.

Regulation of matrix metalloproteinases-8, -9 and endogenous tissue inhibitor-1 in oral biofluids during pregnancy and postpartum

OBJECTIVE

During pregnancy, mothers undergoe considerable physiological changes affecting the whole body including periodontal tissues. Susceptibility to gingival inflammation during pregnancy could be mediated by modulation of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). Therefore, the aim of this study was to investigate salivary and gingival crevicular fluid (GCF) levels of MMPs and TIMPs during the second and third trimester of pregnancy and postpartum.

DESIGN

Saliva and GCF samples were collected from 96 pregnant women (PW) before and after giving birth. The sixty matched non-pregnant women (N-PW) were recruited as a control group and full-mouth periodontal examination was performed. The levels of MMP-8, MMP-9 and TIMP-1 were determined by immunofluorometric and enzyme-linked immunosorbent assays.

RESULTS

The PW group exhibited significantly higher levels of MMP-8 and MMP-9 in their saliva than the N-PW group while corresponding salivary TIMP-1 levels were significantly lower in NPW compared to the postpartum stage. This resulted in significantly higher MMP-8/TIMP-1 and MMP-9/TIMP-1ratio in the saliva from PW before and after birth than in that from N-PW. MMP-8, MMP-9 and TIMP-1 levels were higher in GCF from PW and postpartum than in that from N-PW.

CONCLUSIONS

MMP-8 and MMP-9 levels in saliva and GCF reflect inflammatory burden during pregnancy. They could be used for monitoring the inflammatory state of gingival tissues during pregnancy.

Oxymatrine alleviates periodontitis in rats by inhibiting inflammatory factor secretion and regulating MMPs/TIMP protein expression1

PURPOSE

To investigate the effect of oxymatrine on periodontitis in rats and related mechanism. Methods: Ninety SD rats were divided into control, model, 10, 20 and 40 mg/kg oxymatrine and tinidazole groups. The periodontitis model was established in later 5 groups. The 10, 20 and 40 mg/kg oxymatrine groups were intragastrically administrated with 10, 20 and 40 mg/kg oxymatrine, respectively. The tinidazole group was intragastrically administrated with 100 mg/kg tinidazole. The treatment duration was 4 weeks. The tooth mobility, gingival and plaque indexes, serum inflammatory factor levels and gingival tissue matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase (TIMP) protein levels were detected. Results: After treatment, compared with model group, in 40 mg/kg oxymatrine group the rat general conditions were obviously improved, the tooth mobility, gingival index and plaque index were significantly decreased (P<0.05), the serum tumor necrosis factor-α, interleukin-1β and prostaglandin E2 levels were significantly decreased (P<0.05), the MMP-2 and MMP-9 protein levels were significantly decreased (P<0.05), and the TIMP-2 protein level was significantly increased (P<0.05). Conclusions: Oxymatrine can alleviate the experimental periodontitis in rats. The mechanism may be related to its inhibiting inflammatory factor secretion and regulating MMPs/TIMP protein expression.

Treponema denticola increases MMP-2 expression and activation in the periodontium via reversible DNA and histone modifications

Host-derived matrix metalloproteinases (MMPs) and bacterial proteases mediate destruction of extracellular matrices and supporting alveolar bone in periodontitis. The Treponema denticola dentilisin protease induces MMP-2 expression and activation in periodontal ligament (PDL) cells, and dentilisin-mediated activation of pro-MMP-2 is required for cellular fibronectin degradation. Here, we report that T. denticola regulates MMP-2 expression through epigenetic modifications in the periodontium. PDL cells were treated with epigenetic enzyme inhibitors before or after T. denticola challenge. Fibronectin fragmentation, MMP-2 expression, and activation were assessed by immunoblot, zymography, and qRT-PCR, respectively. Chromatin modification enzyme expression in T. denticola-challenged PDL cells and periodontal tissues were evaluated using gene arrays. Several classes of epigenetic enzymes showed significant alterations in transcription in diseased tissue and T. denticola-challenged PDL cells. T. denticola-mediated MMP-2 expression and activation were significantly reduced in PDL cells treated with inhibitors of aurora kinases and histone deacetylases. In contrast, DNA methyltransferase inhibitors had little effect, and inhibitors of histone acetyltransferases, methyltransferases, and demethylases exacerbated T. denticola-mediated MMP-2 expression and activation. Chronic epigenetic changes in periodontal tissues mediated by T. denticola or other oral microbes may contribute to the limited success of conventional treatment of chronic periodontitis and may be amenable to therapeutic reversal.

Epithelial barrier and oral bacterial infection

The oral epithelial barrier separates the host from the environment and provides the first line of defense against pathogens, exogenous substances and mechanical stress. It consists of underlying connective tissue and a stratified keratinized epithelium with a basement membrane, whose cells undergo terminal differentiation resulting in the formation of a mechanically resistant surface. Gingival keratinocytes are connected by various transmembrane proteins, such as tight junctions, adherens junctions and gap junctions, each of which has a specialized structure and specific functions. Periodontal pathogens are able to induce inflammatory responses that lead to attachment loss and periodontal destruction. A number of studies have demonstrated that the characteristics of pathogenic oral bacteria influence the expression and structural integrity of different cell-cell junctions. Tissue destruction can be mediated by host cells following stimulation with cytokines and bacterial products. Keratinocytes, the main cell type in gingival epithelial tissues, express a variety of proinflammatory cytokines and chemokines, including interleukin-1alpha, interleukin-1beta, interleukin-6, interleukin-8 and tumor necrosis factor-alpha. Furthermore, the inflammatory mediators that may be secreted by oral keratinocytes are vascular endothelial growth factor, prostaglandin E2 , interleukin-1 receptor antagonist and chemokine (C-C motif) ligand 2. The protein family of matrix metalloproteinases is able to degrade all types of extracellular matrix protein, and can process a number of bioactive molecules. Matrix metalloproteinase activities under inflammatory conditions are mostly deregulated and often increased, and those mainly relevant in periodontal disease are matrix metalloproteinases 1, 2, 3, 8, 9, 13 and 24. Viral infection may also influence the epithelial barrier. Studies show that the expression of HIV proteins in the mucosal epithelium is correlated with the disruption of epithelial tight junctions, suggesting a possible enhancement of human papilloma virus infection by HIV-associated disruption of tight junctions. Altered expression of matrix metalloproteinases was demonstrated in keratinocytes transformed with human papilloma virus-16 or papilloma virus-18,. To summarize, the oral epithelium is able to react to a variety of exogenous, possibly noxious influences.

Matrix metalloproteinase-2, -9, and tissue inhibitor of MMP-2 gene polymorphisms in Taiwanese periodontitis patients

Background/purpose

Matrix metalloproteinases (MMPs) and tissue inhibitor of MMPs (TIMPs) have been shown to play an important role in the pathogenesis of tissue destruction in periodontitis. The associations between single nucleotide polymorphisms (SNPs) in the promoter regions of MMP-2, MMP-9, and TIMP-2 genes and the risk of aggressive periodontitis (AgP) and chronic periodontitis (CP) were investigated in a Taiwanese population.

Materials and methods

MMP-2 C-1306T, C-735T, T-790G, and MMP-9 C-1562T and TIMP-2 G-418C SNPs were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis in 69 patients and 129 patients with AgP and CP, respectively, and 117 periodontal healthy individuals who served as healthy controls (HC). Chi-square test and logistic regression analysis were used to investigate the possible association of genotypes with periodontitis.

Results

No significant differences in the distributions of the C-1306T and C-735T variants between periodontitis and HC were detected. Patients with genotype of MMP-2 -790 TT or T allele of MMP-2-790T/G as compared to genotypes of GT + GG genotypes or G allele, were less susceptible to CP [odds ratio (OR) = 0.50, 95% confidence interval (CI) = 0.25–1.00 and OR = 0.52, 95% CI = 0.28–0.96, respectively]. The frequencies of TIMP-2 G-418C gene polymorphisms in nonsmokers were statistically significantly different among AgP, CP, and HC groups (P = 0.024). The nonalcohol drinking participants with C allele of MMP-9 C-1562T as compared to T allele, were less susceptible to AgP (adjusted OR = 0.4; 95% CI, 0.18–0.90).

Conclusion

It is suggested that MMP-2 T-790G, MMP-9 C-1562T, and TIMP-2 G-418C gene polymorphisms might be associated with periodontitis in the Taiwanese Han population.

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.

Gingival fibroblasts from periodontitis patients exhibit inflammatory characteristics in vitro

OBJECTIVE

Gingival fibroblasts (GFs) are an important regulatory cell type in the progression of periodontitis. This study aimed to compare the expression levels of genes associated with inflammation, extracellular matrix degradation and bone destruction in GFs isolated from healthy and periodontitis subjects in the absence and presence of Porphyromonas gingivalis.

DESIGNS

Primary GFs from healthy (n=10) and periodontitis subjects (n=10) were stimulated in vitro with viable P. gingivalis ATCC 49417 and 3 clinical isolates of P. gingivalis with type II fimbriae from one healthy subject (KUMC-H1) and two periodontitis patients (KUMC-P1, -P2). The mRNA expression of proinflammatory cytokines (interleukin (IL)-6, IL-8, IL-1B), anti-inflammatory cytokines (IL-4, IL-10), matrix metalloproteinase (MMP)-1 and 2, tissue inhibitor matrix metalloproteinase (TIMP)-3 and osteoprotegerin (OPG) were assessed using real-time PCR. The levels of IL-6, IL-1β and TIMP-3 protein were measured by an enzyme-linked immunosorbent assay.

RESULTS

The mRNA expression of IL-6, IL-1B and TIMP-3 was higher in the periodontitis group compared with the healthy group, whereas IL-4 expression was higher in the healthy group both in the absence and presence of the P. gingivalis strains. The expression levels of IL-6, IL-1β and TIMP-3 protein were also higher in the periodontitis group in the absence and/or presence of the P. gingivalis strains. There was inter-strain variability among P. gingivalis strains in the ability to induce expression of the proinflammatory cytokines, MMPs and OPG and in the ability to degrade IL-6 protein.

CONCLUSION

High expression of proinflammatory cytokines and TIMP-3 and low expression of IL-4 can be a signature of GFs associated with periodontitis.

Matrix metalloproteinases and periodontal diseases

Periodontitis is a chronic inflammatory disorder characterized a complex interaction between periodontopathic bacteria and the host inflammatory response resulting in release of pro-inflammatory cytokines leading to the destruction of periodontal tissues and alveolar bone. One of the important host factors involved in periodontal diseases is matrix metalloproteinases (MMPs), which is responsible for collagen and extracellular matrix (ECM) degradation of the periodontal tissues. MMPs comprise a family of around 25 members broadly categorized into six groups, which are involved in various physiological and pathological conditions. The activities of MMP are generally balanced by endogenous inhibitors such as tissue inhibitors of metalloproteinase (TIMP), and any imbalance between MMP and TIMP levels plays an important role in the disease progression. Assessment of MMP in tissues, GCF, and saliva may serve as an important biomarker in diagnosis of periodontal diseases and also for prognostic follow-up. Targeted therapy aimed at reducing effects of MMP may serve as a useful adjunct for treatment of periodontitis. This review provides an overview of MMP and its role in various physiological and pathological conditions with emphasis on its association with periodontal diseases. A note on its inhibitors and therapeutic importance is also provided.

Transcriptional profiling of bone marrow stromal cells in response to Porphyromonas gingivalis secreted products

Periodontitis is an infectious inflammatory disease that destroys the tooth-supporting (periodontal) tissues. Porphyromonas gingivalis is an oral pathogen highly implicated in the pathogenesis of this disease. It can exert its effects to a number of cells, including osteogenic bone marrow stromal cells which are important for homeostastic capacity of the tissues. By employing gene microarray technology, this study aimed to describe the overall transcriptional events (>2-fold regulation) elicited by P. gingivalis secreted products in bone marrow stromal cells, and to dissect further the categories of genes involved in bone metabolism, inflammatory and immune responses. After 6 h of challenge with P. gingivalis, 271 genes were up-regulated whereas 209 genes were down-regulated, whereas after 24 h, these numbers were 259 and 109, respectively. The early (6 h) response was characterised by regulation of genes associated with inhibition of cell cycle, induction of apoptosis and loss of structural integrity, whereas the late (24 h) response was characterised by induction of chemokines, cytokines and their associated intracellular pathways (such as NF-κB), mediators of connective tissue and bone destruction, and suppression of regulators of osteogenic differentiation. The most strongly up-regulated genes were lipocalin 2 (LCN2) and serum amyloid A3 (SAA3), both encoding for proteins of the acute phase inflammatory response. Collectively, these transcriptional changes elicited by P. gingivalis denote that the fundamental cellular functions are hindered, and that the cells acquire a phenotype commensurate with propagated innate immune response and inflammatory-mediated tissue destruction. In conclusion, the global transcriptional profile of bone marrow stromal cells in response to P. gingivalis is marked by deregulated homeostatic functions, with implications in the pathogenesis of periodontitis.

Oxidative damage in human gingival fibroblasts exposed to cigarette smoke

Cigarette smoke, a complex mixture of over 7000 chemicals, contains many components capable of eliciting oxidative stress, which may induce smoking-related disorders, including oral cavity diseases. In this study, we investigated the effects of whole (mainstream) cigarette smoke on human gingival fibroblasts (HGFs). Cells were exposed to various puffs (0.5-12) of whole cigarette smoke and oxidative stress was assessed by 2',7'-dichlorofluorescein fluorescence. The extent of protein carbonylation was determined by use of 2,4-dinitrophenylhydrazine with both immunocytochemical and Western immunoblotting assays. Cigarette smoke-induced protein carbonylation exhibited a puff-dependent increase. The main carbonylated proteins were identified by means of two-dimensional electrophoresis and MALDI-TOF mass spectrometry (redox proteomics). We demonstrated that exposure of HGFs to cigarette smoke decreased cellular protein thiols and rapidly depleted intracellular glutathione (GSH), with a minimal increase in the intracellular levels of glutathione disulfide and S-glutathionylated proteins, as well as total glutathione levels. Mass spectrometric analyses showed that total GSH consumption is due to the export by the cells of GSH-acrolein and GSH-crotonaldehyde adducts. GSH depletion could be a mechanism for cigarette smoke-induced cytotoxicity and could be correlated with the reduced reparative and regenerative activity of gingival and periodontal tissues previously reported in smokers.

Nuclear localization of matrix metalloproteinases

Matrix metalloproteinases (MMPs) were originally identified as matrixin proteases that act in the extracellular matrix. Recent works have uncovered nontraditional roles for MMPs in the extracellular space as well as in the cytosol and nucleus. There is strong evidence that subspecialized and compartmentalized matrixins participate in many physiological and pathological cellular processes, in which they can act as both degradative and regulatory proteases. In this review, we discuss the transcriptional and translational control of matrixin expression, their regulation of intracellular sorting, and the structural basis of activation and inhibition. In particular, we highlight the emerging roles of various matrixin forms in diseases. The activity of matrix metalloproteinases is regulated at several levels, including enzyme activation, inhibition, complex formation and compartmentalization. Most MMPs are secreted and have their function in the extracellular environment. MMPs are also found inside cells, both in the nucleus, cytosol and organelles. The role of intracellular located MMPs is still poorly understood, although recent studies have unraveled some of their functions. The localization, activation and activity of MMPs are regulated by their interactions with other proteins, proteoglycan core proteins and / or their glycosaminoglycan chains, as well as other molecules. Complexes formed between MMPs and various molecules may also include interactions with noncatalytic sites. Such exosites are regions involved in substrate processing, localized outside the active site, and are potential binding sites of specific MMP inhibitors. Knowledge about regulation of MMP activity is essential for understanding various physiological processes and pathogenesis of diseases, as well as for the development of new MMP targeting drugs.

Are peri-implantitis lesions different from periodontitis lesions?

AIM

To compare histopathological characteristics of peri-implantitis and periodontitis lesions.

METHODS

A search was conducted on publications up to July 2010. Studies carried out on human biopsy material and animal experiments were considered.

RESULTS

While comprehensive information exists regarding histopathological characteristics of human periodontitis lesions, few studies evaluated peri-implantitis lesions in human biopsy material. Experimental peri-implantitis lesions were evaluated in 10 studies and three of the studies included comparisons to experimental periodontitis. Human biopsy material: the apical extension of the inflammatory cell infiltrate (ICT) was more pronounced in peri-implantitis than in periodontitis and was in most cases located apical of the pocket epithelium. Plasma cells and lymphocytes dominated among cells in both types of lesions, whereas neutrophil granulocytes and macrophages occurred in larger proportions in peri-implantitis.

EXPERIMENTAL STUDIES

placement of ligatures together with plaque formation resulted in loss of supporting tissues and large ICTs around implants and teeth. Following ligature removal, a "self-limiting" process occurred in the tissues around teeth with a connective tissue capsule that separated the ICT from bone, while in peri-implant tissues the ICT extended to the bone crest.

CONCLUSION

Despite similarities regarding clinical features and aetiology of peri-implantitis and periodontitis, critical histopathological differences exist between the two lesions.

Effects of whole cigarette smoke on human gingival fibroblast adhesion, growth, and migration

The aim of this study was to investigate the effects of a single exposure to whole cigarette smoke on human gingival fibroblast behavior. Normal oral mucosa fibroblasts were exposed once to whole cigarette smoke for 5, 15, or 30 min, and then were used to analyze cell adhesion, β1-integrin expression, cell growth and viability, cell capacity to contract collagen gel, and cell migration following wound infliction. Our findings showed that when gingival fibroblasts were exposed once to whole cigarette smoke, this resulted in a significant inhibition of cell adhesion, a decrease in the number of β1-integrin-positive cells, increased LDH activity in the target cells, and reduced growth. The smoke-exposed fibroblasts were also not able to contract collagen gel matrix and migrate following insult. Overall results demonstrate that a single exposure to whole cigarette smoke produced significant morphological and functional deregulation in gingival fibroblasts. This may explain the higher predisposition of tobacco users to oral infections and diseases such as cancer.

Effect of atorvastatin on chronic periodontitis: a randomized pilot study

AIM

We studied the effect of atorvastatin (ATV) treatment on bone loss prevention in subjects with chronic periodontitis.

MATERIAL AND METHODS

In this controlled double-blind study, 38 subjects with chronic periodontitis were randomized into two groups, paired by age to receive ATV (20 mg) or placebo daily for 3 months. Periodontal mechanical treatment was carried out in both groups at baseline. Clinical and radiographic parameters and bone turnover markers were assessed at baseline and at 3 months.

RESULTS

Periodontal disease conditions improved in both groups. After comparing the figures of change, significant improvements were observed in cholesterol levels (Δ=-58.5 ± 37.6 versusΔ=5.4 ± 41.2 mg/dl, p<0.0002), low-density lipoprotein levels (Δ=-48.1 ± 31.7 versusΔ=1.9 ± 42.8 mg/dl, p<0.002), dental mobility (Δ=-0.17 ± 0.11 versusΔ=-0.06 ± 0.11%, p<0.04), and the distance from the crestal alveolar bone to the cemento-enamel junction (Δ=-0.75 ± 0.7 versusΔ=0.09 ± 0.4 mm, p<0.0006) in the ATV group.

CONCLUSIONS

The results suggest that ATV might have beneficial effects on bone alveolar loss and tooth mobility in subjects with periodontal disease.