Altered gene expression levels of matrix metalloproteinases and their inhibitors in periodontitis-affected gingival tissue

Aloe juvenna Brandham & S.Carter as α-Amylase Inhibitor and Hypoglycaemic Agent with Anti-inflammatory Properties for Diabetes Management

Despite Aloe's traditional use, Aloe juvenna Brandham & S.Carter is poorly characterized. Other Aloes are known for their antidiabetic activity. This study describes the antidiabetic potentials and phytoconstituents of the A. juvenna leaves methanolic extract (AJME). Twenty-six phytoconstituents of AJME were described using HPLC/MS-MS. Lupeol and vitexin were isolated using column chromatography. The antidiabetic activity of AJME was investigated using an in vivo high-fat diet/streptozotocin-induced diabetic rat model and in vitro α-glucosidase and α-amylase inhibitory activity assays. AJME demonstrated its α-amylase inhibitory activity (IC50=313±39.9 ppm) with no effect on α-glucosidase. In vivo, AJME dose-dependently improved hyperglycaemia in a high-fat diet/streptozotocin-induced diabetic rat model. Notably, the higher dose (1600 mg/kg) of AJME significantly downregulated serum interleukin-6, tumor necrosis factor-α, and matrix metalloproteinase-1 genes, suggesting its anti-inflammatory effect. These findings indicate AJME's potential as a significant antidiabetic agent through its α-amylase inhibition, hypoglycaemic, and anti-inflammatory properties.

Differential gene expression of ADAMTS-1, ADAMTS-9 and TIMP-3 in periodontitis

A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) are metalloproteinases that bind to components of the extracellular matrix (ECM) to regulate tissue remodeling and homeostasis. ADAMTS can be inhibited by tissue inhibitors of metalloproteinases (TIMPs). Expression of ADAMTS increases under inflammatory conditions. We investigated the mRNA expression of ADAMTS-1, ADAMTS-9 and TIMP-3 genes in both healthy gingival tissues and periodontitis. Clinical periodontal measurements were conducted and gingival biopsies were obtained from stage IIIgrade C generalized periodontitis and healthy (control) groups. mRNA expression was evaluated using real-time quantitative polymerase chain reaction (RTqPCR). All clinical periodontal parameters were significantly higher in the periodontitis group than for the control group. ADAMTS-1 levels were significantly higher in the periodontitis group and were significantly correlated with clinical attachment level and probing pocket depth. Differences in ADAMTS-9 and TIMP-3 mRNA in the periodontitis group compared to the control group were not statistically significant. Increased ADAMTS-1 mRNA expression in periodontitis indicates that members of the ADAMTS family of metalloproteinases are associated with pathogenesis and progression of periodontal disease. Maintaining balance between ADAMTS and TIMP is important for limiting ECM catabolism and preventing tissue damage.

Matrix Metalloproteinase-3 but Not Matrix Metalloproteinase-9, Implicated in the Manifestation of Chronic Periodontitis

Background

Periodontal disease is an inflammatory condition affecting the tooth's supporting tissues, resulting in gradual loss of periodontal ligament (PDL), alveolar bone, and gum resorption. Neutrophil and monocyte/macrophage, destructive proteases like matrix metalloproteinase (MMP)-3 and MMP-9 play pivotal roles in such lesions in periodontitis. Therefore, this study aims to compare the level of MMP-3 and MMP-9 gene expression in patients with or without periodontitis in an Iranian population.

Methods

This cross-sectional study was carried out on 22 chronic periodontitis patients and 17 healthy control subjects referred to the department of periodontology, Mashhad Dental School. In both groups, the gingival tissue was removed during surgery and transferred to the Molecular Biology Laboratory for MMP-3 and MMP-9 gene expression evaluation. The qRT-PCR, TaqMan method was used for gene expression assessments.

Results

The average age of periodontitis patients was 33± 5 years, and in controls, 34.7± 6 with no significant differences. The mean MMP-3 expression in periodontitis patients was 146.67±38.7, and in controls, 63.4±9.1. The difference was statistically significant (P=0.04). The mean expression of MMP-9 in periodontitis patients and controls were 103.8± 21.66 and 87.57± 16.05, respectively. Although the target gene expression in patients was higher, the difference was insignificant. Furthermore, there was not any significant correlation between age or gender with the expression of MMP3 or MMP9.

Conclusion

The study demonstrated that the MMP3 seems to have a destructive impact on the gingival tissue in chronic periodontitis, but not MMP9.

Biological Roles of Fibroblasts in Periodontal Diseases

Periodontal diseases include periodontitis and gingival overgrowth. Periodontitis is a bacterial infectious disease, and its pathological cascade is regulated by many inflammatory cytokines secreted by immune or tissue cells, such as interleukin-6. In contrast, gingival overgrowth develops as a side effect of specific drugs, such as immunosuppressants, anticonvulsants, and calcium channel blockers. Human gingival fibroblasts (HGFs) are the most abundant cells in gingival connective tissue, and human periodontal ligament fibroblasts (HPLFs) are located between the teeth and alveolar bone. HGFs and HPLFs are both crucial for the remodeling and homeostasis of periodontal tissue, and their roles in the pathogenesis of periodontal diseases have been examined for 25 years. Various responses by HGFs or HPLFs contribute to the progression of periodontal diseases. This review summarizes the biological effects of HGFs and HPLFs on the pathogenesis of periodontal diseases.

Matrix metalloproteinase-9-1562 C/T promoter gene polymorphism in chronic periodontitis: A cross-sectional observational study

Background:

Matrix metalloproteinases (MMPs) are a major group of enzymes, released in inflamed periodontal tissues in large quantities, resulting in connective tissue matrix breakdown. One of the most predominant MMPs is MMP-9. Association between chronic periodontitis (CP) and MMP-9 gene polymorphism (GP) in some ethnic populations has been already established. The aim of the current study was to assess the association of single-nucleotide polymorphism in the promoter region of MMP-9 gene with CP in Kolkata population, if any.

Materials and Methods:

Forty eligible individuals were recruited for the study and grouped as A and B: Group A (twenty periodontally healthy individuals) and Group B (twenty CP patients). Venous blood samples collected from all the forty individuals were used to isolate the genomic DNA. GP for MMP-9 gene was detected using polymerase chain reaction and sequencing method. The data obtained were then analyzed statistically.

Results:

A significantly different genotypic and allelic variation was observed in the control and test groups, with C/T genotype and T allele present in only CP group.

Conclusion:

Within the limitations of this study, we can conclude that there was no significant association between patients with periodontitis and MMP-9-1562 C/T promoter GP.

Matrix metalloproteinase-induced cervical extracellular matrix remodelling in pregnancy and cervical cancer

Abstract

The phenomenal extracellular matrix (ECM) remodelling of the cervix that precedes the myometrial contraction of labour at term or preterm appears to share some common mechanisms with the occurrence, growth, invasion and metastasis of cervical carcinoma. Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that are pivotal to the complex extracellular tissue modulation that includes degradation, remodelling and exchange of ECM components, which contribute to homeostasis under normal physiological conditions such as cervical remodelling during pregnancy and puerperium. However, in cancer such as that of the uterine cervix, this extensive network of extracellular tissue modulation is altered leading to disrupted cell-cell and cell-basement membrane adhesion, abnormal tissue growth, neovascularization and metastasis that disrupt homeostasis. Cervical ECM remodelling during pregnancy and puerperium could be a physiological albeit benign neoplasm. In this review, we examined the pathophysiologic differences and similarities in the role of MMPs in cervical remodelling and cervical carcinoma.

Lay summary

During pregnancy and childbirth, the cervix, which is the barrel-shaped lower portion of the womb that connects to the vagina, gradually softens, shortens and opens to allow birth of the baby. This process requires structural and biochemical changes in the cervix that are stimulated by enzymes known as matrix metalloproteinases. Interestingly, these enzymes also affect the structural and biochemical framework of the cervix during cervical cancer, although cervical cancers usually occur after infection by human papillomavirus. This review is intended to identify and explain the similarities and differences between the structural and chemical changes in the cervix during pregnancy and childbirth and the changes seen in cervical cancer.

Does oral lichen planus aggravate the state of periodontal disease? A systematic review and meta-analysis

BACKGROUND

The objective of this systematic review and meta-analysis (SRM) was to assess the evidence between the association of oral lichen planus and periodontal disease, evaluating the periodontal clinical parameters and biomarkers levels.

METHODS

This systematic review and meta-analysis followed PRISMA and was registered in PROSPERO (CRD42020181513). Searches were accomplished in databases for articles published until June 2021. The meta-analysis was performed with the variables: plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment loss (CAL). The mean difference was applied with a 95% confidence interval.

RESULTS

Six articles were included. Qualitative analysis showed the levels of biomarkers (matrix metalloproteinases, interleukins, and periodontal microbiological profile) are increased in subjects with periodontal disease and oral lichen planus. In the meta-analysis, these subjects also presented increases in all periodontal clinical parameters evaluated: GI-gingivitis 0.22 [0.14, 0.31] p < 0.0001 and periodontitis 0.12 [0.06, 0.19] p = 0.0003; PI-gingivitis 0.22 [0.12, 0.31] p < 0.0001 and periodontitis 0.15 [0.08, 0.23] p < 0.0001; PD-gingivitis 0.27 [0.06; 0.48] p = 0.0107 and periodontitis 0.11 [0.01; 0.21] p = 0.0299; and CA-periodontitis 0.06 [0.01, 0.12] p = 0.0176.

CONCLUSIONS

Evidence suggests a significant relationship between the severity of periodontal disease and the presence of oral lichen planus. Although the association is biologically plausible, further studies are needed using populations and well-defined biochemical and clinical outcomes with consideration of potential confounding factors.

CLINICAL RELEVANCE

This SRM provides information on the interaction between OLP and periodontal disease and guides clinicians to make evidence-based decisions and suggests recommendations for further high-quality studies.

Exopolysaccharides Producing Lactic Acid Bacteria in Wine and Other Fermented Beverages: For Better or for Worse?

Lactic acid bacteria (LAB) from fermented beverages such as wine, cider and beer produce a wide range of exopolysaccharides (EPS) through multiple biosynthetic pathways. These extracellular polysaccharides constitute key elements for bacterial species adaptation to such anthropic processes. In the food industry, LAB polysaccharides have been widely studied for their rheological, functional and nutritional properties; however, these have been poorly studied in wine, beer and cider until recently. In this review, we have gathered the information available on these specific polysaccharide structure and, biosynthetic pathways, as well as the physiology of their production. The genes associated with EPS synthesis are also presented and compared. Finally, the possible role of EPS for bacterial survival and spread, as well as the risks or possible benefits for the winemaker and the wine lover, are discussed.

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.

Effects of IL-1β on MMP-9 Expression in Cementoblast-Derived Cell Line and MMP-Mediated Degradation of Type I Collagen

It has been reported that matrix metalloproteinases (MMPs) are induced by many cytokines, and they are involved in various inflammatory processes, including periodontitis. However, the effects of interleukin-1β (IL-1β) on MMP-9 expression in cementoblasts, the cells responsible for cementum production, remain largely unknown. In this study, we used qPCR and gelatin zymogram analysis to show that IL-1β upregulated MMP-9 expression in cementoblast-derived cell line. Several signaling pathways, such as ERK1/2, JNK, p38, and AP-1 (c-Fos and ATF-2), were activated in response to IL-1β stimulation. Furthermore, enhancement of AP-1 activity by IL-1β was further confirmed by the AP-1 reporter assay and the electrophoretic mobility shift assay (EMSA). Pretreatment with specific inhibitors of ERK1/2 (U0126), JNK (SP600125), and AP-1 (tanshinone IIA) attenuated IL-1β-induced MMP-9 expression. In addition, inhibitors of ERK1/2 (U0126) and JNK (SP600125) attenuated IL-1β-enhanced AP-1 activity. This suggested that IL-1β stimulated AP-1 activation, at least partially, through ERK1/2 and JNK signaling pathways. Moreover, we found that IL-1β also upregulated the expression of MMP-13 and enhanced MMP-mediated degradation of type I collagen. Collectively, these results suggested that IL-1β induced MMP-9 expression by activation of AP-1 through the ERK1/2 and JNK signaling pathways in cementoblast-derived cell line and enhanced MMP-mediated collagen degradation possibly by MMP-13 and MMP-9.

Investigation of active matrix- metaloproteinase-8 (aMMP-8) as a reference parameter for path control in antimicrobial photothermal therapy (aPTT) using a split-mouth design

OBJECTIVES

This retrospective data-collection study aims to explain how the active matrix-metalloproteinase-8-titer (aMMP-titer) influences the immune response of the subject. This is done through monotherapy scaling and root planing (SRP) which is then compared to SRP combined with antimicrobial photothermal therapy (aPTT, Emundo®).

METHODS

Data collection was monocentric, randomized and split-mouth based. A study group of twenty patients with chronic periodontal disease with a periodontal pocket depth (PPD) 4 mm ≤ PPD ≤8 mm, a periodontal screening index (PSI: > 3), and a gingival recession ≤2 mm were selected.A diode laser, manufactured by A.R.C. Laser GmbH, with 810 nm wavelength was used. This device implemented three different light transmission systems for transgingival and intra-gingival irradiation. Power settings between 200 and 300 mW were deployed for 10 s during all treatment steps. The photothermic dye of EmunDo® system (A.R.C. Laser GmbH) was infracyaningreen.The adjuvant effect of the antimicrobial photothermal therapy (aPTT) with EmunDo® in combination with conventional SRP on the teeth 15 and 35 was compared with the results of monotherapy SRP on teeth 25 and 45.

RESULTS

A reduction of the aMMP-8-titer in gingival crevicular fluid (GCF) was observed in both groups (follow up group and control group) after one month. However; the decrease in the follow up group under SRP in combination with aPTT was significantly more pronounced. The periodontal pocket depths was reduced in both treatment groups. The periodontal probing depth (in mm) shows a larger decrease of the periodontal pocket depth within the follow up group (SPR with aPTT) compared with the control group (SRP).

CONCLUSION

The aMMP-8-titer showed differences in both groups prior to and after treatment. Active matrix-metalloproteinase-8 (aMMP-8) as a reference parameter for path control in antimicrobial photothermal therapy (aPTT) seems acceptable.

Effect of sonic versus manual supervised toothbrushing on both clinical and biochemical profiles of patients with desquamative gingivitis associated with oral lichen planus: A randomized controlled trial

OBJECTIVES

The aim of this randomized, parallel-design, clinical trial was to investigate the effectiveness of an intensive plaque control programme with sonic versus manual toothbrushing on clinical outcomes and gingival crevicular fluid (GCF) levels of matrix metalloproteinases (MMP) in desquamative gingivitis (DG) patients.

METHODS

A total of 32 patients affected by DG secondary to oral lichen planus (OLP) were consecutively recruited and randomly assigned to a test (n = 16) and control (n = 16) group. Both groups were enrolled in an intensive control programme comprising supragingival scaling and polishing, and brush-specific instructions for a period of 8 weeks. The treatment of interest (test) was the use of a sonic-powered toothbrush, and the standard treatment (control) was the utilization of a soft-bristle manual toothbrush for twice-daily home oral hygiene procedures. Periodontal parameters, patient-centred outcomes, MMP-1 and MMP-9 GCF levels were evaluated at baseline and 8 weeks after starting the programme.

RESULTS

The plaque control programme resulted in statistically significant reduction in periodontal parameters with consequent improvement in the clinical features, painful symptoms and severity of DG lesions in both groups (all P < 0.001). When a sonic toothbrush was used, there was a more significant decrease in clinical indices, mucosal disease scores and GCF levels of MMP-1 and MMP-9.

CONCLUSIONS

This clinical trial reported the effectiveness of a combined protocol based on professional oral hygiene and supervised toothbrushing in OLP patients with DG. The daily use of a sonic toothbrush would seem to perform better in the short term.

Assessment of microRNA-144-5p and its putative targets in inflamed gingiva from chronic periodontitis patients

BACKGROUND AND OBJECTIVE

This study aimed to discover the distinctive MicroRNAs (miRNA) functioning in the pathogenesis of periodontal inflammation, which might be potential therapy targets of chronic periodontitis.

MATERIAL AND METHODS

miRNA profiles of human inflamed gingival tissue from three previous microarrays were re-analysed. Gingival tissues were collected for the validation of overlapping miRNAs, and a network was constructed to show regulatory connection between overlapping miRNAs and periodontitis-associated target genes. Potential miRNAs were screened based on their expression levels and predicted target genes. Correlation analysis and binding site prediction were conducted to reveal the relationship between the potential miRNAs and their target genes.

RESULTS

miR-144-5p, found to be upregulated in all three studies, showed the greatest upregulation (P < 0.0001). Another 16 miRNAs (10 upregulated and six downregulated) overlapped between any two of the three studies. All overlapping miRNAs had expected expression levels except for miR-203 during validation. Ten miRNAs (six upregulated and four downregulated) were found to have periodontal inflammation-associated targets. Cyclooxygenase 2 (COX2) and interleukin-17F (IL17F), predicted target genes of upregulated miR-144-5p, showed significant decreases and were negatively correlated with miR-144-5p in the periodontitis group (r = -0.742 for COX2, r = -0.615 for IL17F).

CONCLUSION

This re-analysis of miRNA signatures has implied the potential regulatory mechanism of miR-144-5p and its potential for exploring alternative therapeutic approaches, especially those that use miRNA delivery systems to treat chronic periodontitis. Nevertheless, further study based on larger sample size and homogenous cells is needed to reveal the exact roles of miRNAs in chronic periodontitis.

Effectiveness of an erbium-doped: yttrium, aluminum and garnet laser for treatment of peri-implant disease: Clinical, microbiological, and biochemical marker analyses

Background

The effectiveness of an erbium-doped: yttrium, aluminum and garnet (Er: YAG) laser (EYL) for the treatment of peri-implant disease (PID) remains unclear. The aim of this study was to compare non-surgical EYL therapy for PID with locally delivered minocycline hydrochloride (MC) ointment therapy by evaluating clinical, microbiological, and biochemical markers.

Material and Methods

Thirty-seven patients with PID were randomly assigned to either the EYL group (n = 18) or the MC group (n = 19). The clinical, microbiological, and biochemical markers at baseline and at 1 and 3 months after treatment were compared between the two groups. Subgingival plaque and peri-implant crevicular fluid (PICF) were collected from the diseased pockets.

Results

In the EYL group, probing pocket depth (PPD) was significantly decreased after treatment when compared with baseline. On the other hand, in the MC group, there was no significant decrease in PPD after treatment. Specific bacteria associated with PID were not determined. The counts of both Gram-positive and -negative species did not significantly decrease in the EYL group at 3 months after treatment. In the MC group, the counts of almost all bacterial species were significantly decreased after treatment. Biochemical marker analysis of PICF revealed significantly lower levels of metalloproteinase (MMP)-9 in the EYL group, as compared with the MC group at 3 months after treatment (p= 0.009).

Conclusions

Non-surgical therapy with an EYL for PID was clinically effective, with decreased MMP-9 levels in PICF, which may lead to reduced peri-implant tissue destruction. Key words:Er: YAG laser; peri-implant disease; biomarker; peri-implant crevicular fluid.

Effect of a structured plaque control on MMP-1 and MMP-9 crevicular levels in patients with desquamative gingivitis associated with oral lichen planus

OBJECTIVES

No data are available in the literature on the extent to which the immune host-response and bacterial-elicited inflammation separately contributes to the increase in gingival crevicular fluid (GCF) levels of inflammatory biomarkers in patients affected by desquamative gingivitis (DG) secondary to oral lichen planus (OLP). The aim of this study was to investigate the effect of a structured plaque control intervention on GCF levels of MMP-1 and MMP-9 in OLP patients with DG and to compare them with those of non-OLP patients.

MATERIALS AND METHODS

The study population consisted of 18 unrelated Caucasian patients with DG, while 18 periodontally healthy subjects were recruited for the control group. Periodontal parameters and GCF biomarker amounts were evaluated at baseline and 2 months after a structured plaque control intervention, comprising professional oral hygiene sessions, manual toothbrushing, and interdental cleaning advice, only for DG patients. Determination of MMP-1 and MMP-9 levels was carried out by means of an enzyme-linked immunosorbent assay.

RESULTS

Plaque control program led to improvement in all examined clinical parameters and resulted in significant decrease in GCF total amount and concentration of MMP-1 and MMP-9 in comparison to baseline (p < 0.001). However, MMP-1 and MMP-9 levels in DG patients were still significantly higher than those in the healthy control group (p < 0.01).

CONCLUSIONS

These findings would seem to support an intrinsic upregulated expression of MMPs in DG patients that is exacerbated by bacterial plaque.

CLINICAL RELEVANCE

The present outcomes provide further scientific grounds for the importance of strict professional oral hygiene sessions in DG patients.

The Effect of MMP-13, MMP-12, and AMBN on Gingival Enlargement and Root Deformation In a New Type of Gingival Fibromatosis

This case compared gene-expression between a new type of idiopathic gingival fibromatosis (IGF) and normal gingiva, to clarify the nature of the gingival overgrowth and dental anomaly. A 6-year-old girl with generalized gingival overgrowth and root deformations was diagnosed with IGF. Gene expression profiles were compared between normal gingiva (N=9) and one IGF gingiva using cDNA microarray. Genes related to regulation of cell proliferation and proteolytic degradation were expressed strongly in IGF. MMP-13 and MMP-12 expression were 120 times and 96 times lower in IGF, respectively, whereas AMBN expression was 79 times higher. RT-PCR and immunohistochemical staining supported the microarray results. Reduced proteolytic activity due to low MMP-13 and MMP-12 expression appears to be a potential mechanism for gingival overgrowth. Genetic investigations, such as expression levels of MMP-13, MMP-12, and AMBN, may enable classification of a new syndrome characterized by gingival enlargement with abnormal root development.

Periodontal response to orthodontic tooth movement in diabetes-induced rats with or without periodontal disease

BACKGROUND

Systemic conditions can influence orthodontic tooth movement. This study evaluates histologic periodontal responses to orthodontic tooth movement in diabetes-induced rats with or without periodontal disease.

METHODS

Forty Wistar rats were divided according their systemic condition (SC) into diabetic (D) and non-diabetic (ND) groups. Each group was subdivided into control (C), orthodontic tooth movement (OM), ligature-induced periodontitis (P) and ligature-induced periodontitis with orthodontic movement (P+OM) groups. Diabetes mellitus (DM) was induced with alloxan monohydrate, and after 30 days, the P group received a cotton ligature around their first lower molar crown. An orthodontic device was placed in OM and P+OM groups for 7 days, and the animals were then euthanized.

RESULTS

Differences in OM between D and ND groups were not significant (6.87± 3.55 mm and 6.81 ± 3.28 mm, respectively), but intragroup analysis revealed statistically significant differences between the P+OM groups for both SCs. Bone loss was greater in the D group (0.16 ± 0.07 mm² ) than in the ND group (0.10 ± 0.03 mm² ). In intragroup analysis of the D condition, the P+OM group differed statistically from the other groups, while in the ND condition, the P+OM group was different from the C and OM groups. There was a statistically significant difference in bone density between D and ND conditions (18.03 ± 8.09% and 22.53 ± 7.72%) in the C, P, and P+OM groups.

CONCLUSION

DM has deleterious effects on bone density and bone loss in the furcation region. These effects are maximized when associated with ligature-induced periodontitis with orthodontic movement.

Extracellular ATP is a key modulator of alveolar bone loss in periodontitis

Periodontal diseases are initiated by pathogenic bacterial biofilm activity that induces a host inflammatory cells immune response, degradation of dento gingival fibrous tissue and its detachment from root cementum. It is well accepted, that osteoclastic alveolar bone loss is governed exclusively through secretion of proinflammatory cytokines. Nevertheless, our findings suggest that once degradation of collagen fibers by MMPs occurs, a drop of cellular strains cause immediate release of ATP from marginal gingival fibroblasts, cell deformation and influx of Ca+2. Increased extracellular ATP (eATP) by interacting with P2×7 purinoreceptors, present on fibroblasts and osteoblasts, induces generation of receptor activator of nuclear factor kB ligand (RANKL) that further activates osteoclastic alveolar bone resorption and bone loss. In addition, increased eATP levels may amplify inflammation by promoting leukocyte recruitment and NALP3-inflammasome activation via P2×7. Then, the inflammatory cells secrete cytokines, interleukin IL-1, TNF and RANKL that further trigger alveolar bone resorption. Moreover, eATP can be secreted from periodontal bacteria that may further contribute to inflammation and bone loss in periodontitis. It seems therefore, that eATP is a key modulator that initiates the pathway of alveolar bone resorption and bone loss in patients with periodontal disease. In conclusion, we propose that strain release in gingival fibroblasts aligned on collagen fibers, due to activity of MMP, activates release of ATP that triggers the pathway of alveolar bone resorption in periodontitis. We predict that by controlling the eATP interaction with its cellular purinoreceptors will reduce significantly bone loss in periodontitis.

Expression of neprilysin in periodontitis-affected gingival tissues

OBJECTIVE

Although the pathogeneses of Alzheimer's disease (AD) and periodontal diseases have overlapping features, including ageing and chronic inflammation, the association between AD and periodontitis remains unclear. To explore the pathogenesis of periodontitis, a comprehensive gene expression/transcriptome analysis in periodontitis-affected gingival tissues found that the AD pathway was significantly up-regulated in periodontitis-affected gingival tissues. AD-related genes, amyloid beta precursor protein (APP), interleukin-1 beta and compliment 1QA, were significantly elevated in periodontitis. In the present study, balance between mRNA expression of APP and a potent amyloid degradation enzyme, neprilysin (NEP), as well as protein localisation of APP and NEP were analysed.

DESIGN

Eighteen periodontitis-affected and 18 clinically healthy control gingival tissues were taken from patients with severe chronic periodontitis or undergoing tooth extraction. Total RNA was purified and used for quantitative reverse transcription real-time polymerase chain reaction (qRT-PCR). The localisation of APP and NEP was analysed by immunohistochemistry (IHC).

RESULTS

Both APP and NEP genes were up-regulated in periodontitis-affected gingival tissues. APP-expressing macrophages and NEP-expressing neutrophils and fibroblasts, reflecting inflammatory stages, were detected in inflamed gingival tissues by IHC.

CONCLUSION

The up-regulation of APP and NEP mRNA levels in periodontitis-affected gingival tissues compared with healthy controls was confirmed by qRT-PCR analyses. Since NEP is one of the primary enzymes that degrades amyloid beta, increased NEP mRNA levels in periodontitis may act as an inhibitor of amyloid beta accumulation in gingival tissues, balancing increased APP mRNA expression. However, NEP has several effects including degradation of vasoactive substances; therefore, further sresearch is needed.

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.

The paradox of painless periodontal disease

Periodontal diseases, primarily gingivitis and periodontitis, are characterised by progressive inflammation and tissue destruction. However, they are unusual in that they are not also accompanied by the pain commonly seen in other inflammatory conditions. This suggests that interactions between periodontal bacteria and host cells create a unique environment in which the pro-algesic effects of inflammatory mediators and factors released during tissue damage are directly or indirectly inhibited. In this review, we summarise the evidence that periodontal disease is characterised by an accumulation of classically pro-algesic factors from bacteria and host cells. We then discuss several mechanisms by which inflammatory sensitisation of nociceptive fibres could be prevented through inactivation or inhibition of these factors. Further studies are necessary to fully understand the molecular processes underlying the endogenous localised hypoalgesia in human periodontal disease. This knowledge might provide a rational basis to develop future therapeutic interventions, such as host modulation therapies, against a wide variety of other human pain conditions.

The impact of smoking on levels of chronic periodontitis-associated biomarkers

OBJECTIVE

To investigate the effect of smoking on the expression levels of matrix metalloproteinase (MMP)-1, MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), and the concentrations of TNF-α and IL-10 in patients with chronic periodontitis (ChP).

METHODS

This is an ex-vivo study. Our study consisted of 78 cases, all of which were diagnosed with ChP and were selected according to the inclusion and exclusion criteria. Among these 78 cases, 38 patients were classified into the smoking group (S-ChP group), and 40 patients in the non-smoking group (NS-ChP group). The clinical periodontal parameters of all patients were recorded, including the plaque index (PLI), probing depth (PD), loss of attachment (LA) and sulcus bleeding index (SBI). Serum was collected from forearm blood to establish a Porphyromonas gingivalis (Pg) internalizing KB cell model. Enzyme-linked immunosorbent assay (ELISA) was used to determine the concentrations of MMP-1, MMP-9 and TIMP-1 in the KB cell lysis solution as well as IL-10 and TNF-α in the gingival crevicular fluid (GCF).

RESULTS

Fewer Pg internalizing KB cell colonies were observed in the NS-ChP group than in the S-ChP group (P<0.01). When 400μL serum was added, there were remarkable differences in the concentrations of MMP-1 and TIMP-1 secreted from the KB cells between the S-ChP and NS-ChP groups (MMP-1: t=-21.71, P<0.01; TIMP-1: t=64.35, P<0.001). Additionally, when 800μL serum was added, there were significant differences in the concentrations of MMP-1, MMP-9 and TIMP-1 in the KB cells between the S-ChP and NS-ChP groups (MMP-1: t=-81.89, P<0.001; MMP-9: t=-15.67, P<0.001; TIMP-1: t=109.4, P<0.001). The TNF-α levels were higher, but the IL-10 levels were lower in the GCF from the ChP patients in the S-ChP group than those in the NS-ChP group (both P<0.001).

CONCLUSION

The serum of S-ChP patients can enhance the concentrations of MMP-1 and MMP-9, but reduce TIMP-1 secreted from Pg internalizing KB cells. However, the concentration of TNF-α was increased and IL-10 was decreased. Abnormal concentrations of ChP-associated biomarkers may be conducive to the development and progression of ChP.

Assessment of MMP-1, MMP-8 and TIMP-2 in experimental periodontitis treated with kaempferol

Purpose

The objective of this study was to investigate the effect of a dietary flavonoid, kaempferol, which has been shown to possess antiallergic, anti-inflammatory, anticarcinogenic, and antioxidant activities on the periodontium by histomorphometric analysis and on gingival tissue matrix metalloproteinase-1 (MMP-1), MMP-8, and tissue inhibitor of metalloproteinase-2 (TIMP-2) by biochemical analysis of rats after experimental periodontitis induction.

Methods

Sixty Wistar rats were randomly divided into six groups of ten rats each, and silk ligatures were placed around the cervical area of the mandibular first molars for 15 days, except in the healthy control rats. In the experimental periodontitis groups, systemic kaempferol (10 mg/kg/2d) and saline were administered by oral gavage at two different periods (with and without the presence of dental biofilm) to all rats except for the ten non-medicated rats. Alveolar bone area, alveolar bone level, and attachment level were determined by histomorphometric analysis, and gingival tissue levels of MMP-1, MMP-8, and TIMP-2 were detected by biochemical analysis.

Results

Significantly greater bone area and significantly less alveolar bone and attachment loss were observed in the kaempferol application groups compared to the control groups (P<0.05). In addition, gingival tissue MMP-1 and -8 levels were significantly lower in the kaempferol application groups compared to the control groups and the periodontitis group (P<0.001). There were no statistically significant differences in TIMP-2 levels between the kaempferol and saline application groups (P>0.05).

Conclusions

Kaempferol application may be useful in decreasing alveolar bone resorption, attachment loss, and MMP-1 and -8 production in experimental periodontitis.

Activation of Receptor Activator of Nuclear Factor-κB Ligand and Matrix Metalloproteinase Production in Periodontal Fibroblasts by Endothelin Signaling

BACKGROUND

Periodontitis is a group of inflammatory diseases affecting the tissues supporting the teeth that will progressively cause the loss of alveolar bone and periodontal ligaments and eventually the dentition. Activation of osteoclast activity by receptor activator of nuclear factor-κB ligand (RANKL) and released enzymes such as matrix metalloproteinases (MMPs) are among the factors involved in the breakdown of the periodontium. However, the mechanisms regulating their production in periodontitis are poorly understood. Endothelin signaling via the activation of the endothelin-A receptor (EDNRA) by endothelin-1 may play a role in the disease because the expression of the receptor and ligand is elevated in the periodontal tissues of patients with periodontitis.

METHODS

Cultured primary human periodontal fibroblasts were treated with 20 and 100 nM endothelin-1 for 6 and 24 hours and then collected to assess MMP and RANKL production by immunoblotting. Inhibitors were used to identify the molecular pathways activated by EDNRA in these cells.

RESULTS

Endothelin-1 stimulated the production of MMP1, MMP8, and RANKL in a dose- and time-dependent manner; blocking EDNRA function with the antagonist TBC3214 inhibited the response, although EDNRA activation had no effects on osteoprotegerin production. These mechanistic studies indicate that EDNRA activates phospholipase C, which then 1) increases the MMP1 protein levels through activation of the extracellular signal-regulated kinase mitogen-activated protein kinase-dependent pathway and 2) upregulates RANKL by a different pathway.

CONCLUSION

These results suggest that EDNRA may function in the breakdown of the periodontal tissues associated with periodontitis by promoting the protein expression of MMPs and RANKL via the phospholipase C pathway.

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.

Exenatide and Sitagliptin Decrease Interleukin 1β, Matrix Metalloproteinase 9, and Nitric Oxide Synthase 2 Gene Expression But Does Not Reduce Alveolar Bone Loss in Rats With Periodontitis

BACKGROUND

New drugs for the treatment of diabetes, glucagon-like peptide-1 (GLP-1) receptor agonists and inhibitors of dipeptidyl peptidase-4 (DPP-4) have shown pleiotropic effects on bone metabolism and anti-inflammatory properties. The aim of this study is to evaluate the effects of exenatide (GLP-1 agonist) and sitagliptin (DPP-4 inhibitor) during periodontitis induction by ligature insertion in rats.

METHODS

Forty rats were divided into four groups: 1) animals with induced periodontitis that received exenatide (EG); 2) animals with induced periodontitis that received sitagliptin (SG); 3) animals with induced periodontitis and without drug treatment (LG); and 4) animals without induced periodontitis and without drug treatment (controls). The drugs were administered for 28 days. On the day the animals were sacrificed, blood was collected for analysis of glucose and DPP-4 levels. The gene expressions of prostaglandin-endoperoxide synthase 2, tissue inhibitor of metalloproteinase 1, Dpp4, nitric oxide synthase 2 (Nos2), interleukin 1β (Il1b), and matrix metalloproteinase 9 (Mmp9) in the gingiva; support and alveolar bone loss; connective tissue attachment; and the quantity of gingival collagen were evaluated.

RESULTS

Exenatide and sitagliptin treatments have led to a lower percentage of weight gain but did not influence glycemia. Sitagliptin reduced the serum concentration of DPP-4. Interestingly, although the gene expression profile has revealed a downregulation of Mmp9, Nos2, and Il1b in both EG and SG compared to LG, a significant protective effect was not observed on alveolar bone and collagen tissue in this model.

CONCLUSION

Regardless of the reduction of the expression of Il1b, Nos2, and Mmp9, the drugs were not effective in the stabilization or reduction of alveolar bone loss and collagen degradation in rats.

Inflammation Biomarkers of Advanced Disease in Nongingival Tissues of Chronic Periodontitis Patients

Chronic periodontitis is a multifactorial inflammatory disease that affects supporting structures of the teeth. Although the gingival response is largely described, little is known about the immune changes in the alveolar bone and neighboring tissues that could indicate periodontal disease (PD) activity. Then, in this study we identified the ongoing inflammatory changes and novel biomarkers for periodontitis in the tissues directly affected by the destructive disease in PD patients. Samples were collected by osteotomy in 17 control subjects during extraction of third molars and 18 patients with advanced PD, in which alveoloplasty was necessary after extraction of teeth with previous extensive periodontal damage. Patients presented mononuclear cells infiltration in the connective tissue next to the bone and higher fibrosis area, along with increased accumulation of IL-17⁺ and TRAP⁺ cells. The levels of TNF-α and MMP-2 mRNA were also elevated compared to controls and a positive and significant correlation was observed between TNF-α and MMP-2 mRNA expression, considering all samples evaluated. In conclusion, nongingival tissues neighboring large periodontal pockets present inflammatory markers that could predict ongoing bone resorption and disease spreading. Therefore, we suggested that the detailed evaluation of these regions could be of great importance to the assessment of disease progression.

TNF-α stimulates MMP-3 production via PGE2 signalling through the NF-kB and p38 MAPK pathway in a murine cementoblast cell line

BACKGROUND

Cementoblasts are considered to play an important role in the homeostasis of periodontal tissues under both physiologic and pathologic conditions. Matrix metalloproteinases (MMPs) is the key family of enzymes participating in extracellular matrix remodelling. In the present study, the effects and regulatory mechanisms of tumour necrosis factor (TNF)-α on the expression of MMPs and their inhibitors (tissue inhibitor of metalloproteinases; TIMPs) were investigated.

MATERIALS AND METHODS

OCCM-30, an immortalised murine cementoblast cell line, was stimulated with TNF-α at 1 and 10ng/ml for 24h. The expression of Mmp-2, Mmp-3, Mmp-13, Mmp-14, Timp-1, and Timp-2 as well as PGE2 was determined. Inhibitors of MAPKs, PI3K/Akt, NF-kB and Cox-2 were employed to reveal possible TNF-α induced regulatory signalling pathway(s). The mRNA and protein expression were analysed by (semi)quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively.

RESULTS

TNF-α dose-dependently stimulated MMP-3 expression by cementoblasts. This was found for mRNA as well as protein expression. No significant differences were found in the mRNA expression of Mmp-2, Mmp-13, Mmp-14, Timp-1, and Timp-2 upon TNF-α stimulation. The level of PGE2, however, was significantly increased along with MMP-3. Treatment with a selective Cox-2 inhibitor resulted in partial suppression of TNF-α-induced Mmp-3 mRNA expression. Addition of PGE2 enhanced Mmp-3 mRNA in a dose dependent manner, suggesting an inductive effect of TNF-α partly via PGE2. The up-regulation of Mmp-3 by TNF-α was completely suppressed by a combination of NF-kB and p38 MAPK inhibitors, while partial suppression was found with each inhibitor. The effect of PGE2 on Mmp-3 expression was abolished by treating cells with an NF-kB inhibitor; a p38 MAPK inhibitor had only a small effect.

CONCLUSIONS

The present study indicates that cementoblasts respond to TNF-α by increasing MMP-3 production partially via PGE2 and signalling through the NF-kB and p38 MAPK pathway. MMP-3 may participate in periodontal tissue degradation/remodelling.

Impact of metronidazole and amoxicillin combination on matrix metalloproteinases-1 and tissue inhibitors of matrix metalloproteinases balance in generalized aggressive periodontitis

OBJECTIVE

Generalized aggressive periodontitis (GAgP) is a complex periodontal disease affecting the entire dentition with a rapid destruction of the periodontium and resulting in loss of teeth. We hypothesized that better clinical healing of adjunctive use of amoxicillin plus metronidazole combination may be related to the effect of this combination therapy to restore imbalance between matrix metalloproteinases (MMP) and their tissue inhibitors (TIMP) which is associated with connective tissue and alveolar bone destruction in patients with GAgP.

MATERIALS AND METHODS

Twenty-eight subjects diagnosed with GAgP were recruited. Patients were randomly assigned to test or control groups. MMP-1/TIMP-1 ratio was compared between groups receiving scaling and root planning (SRP) alone (control) or in combination with amoxicillin plus metronidazole (test). Clinical periodontal variables were measured. Gingival crevicular fluid samples were obtained and analyzed for MMP-1 and TIMP-1. Measurements were taken at baseline and repeated at 3 and 6 months after therapy.

RESULTS

Total MMP-1 levels were significantly decreased in both groups (P < 0.05) at 3 and 6 months. MMP-1 concentration levels showed a similar pattern to MMP-1 total levels decreasing significantly at 3 months (P < 0.05). TIMP-1 concentration levels increased in the test group throughout the study period, while the difference did not reach statistical significance (P > 0.05). TIMP-1/MMP-1 balance was restored in test group at 6 months significantly better than the control group (P < 0.05).

CONCLUSION

The results of this study suggest that metronidazole and amoxicillin combination as an adjunct to SRP results in better clinical healing through restoring TIMP-1/MMP-1 balance.

Resistance of MMP9 and TIMP1 to endotoxin tolerance

Inflammatory cytokines activate tissue collagenases such as matrix metalloproteinases (MMPs). MMPs are antagonized by tissue inhibitors of metalloproteinases (TIMPs) that attempt to regulate excessive collagenase activity during inflammatory conditions. During chronic inflammatory conditions, induction of endotoxin tolerance negatively regulates the cytokine response in an attempt to curtail excessive host tissue damage. However, little is known about how downregulation of inflammatory cytokines during endotoxin tolerance regulates MMP activities. In this study, human monocyte-derived macrophages were either sensitized or further challenged to induce tolerance with lipopolysaccharide (LPS) from Porphyromonas gingivalis (PgLPS) or Escherichia coli (EcLPS). Inflammatory cytokines, such as TNF-α and IL-1β, and levels of MMP9 and TIMP1 were analyzed by a combination of cytometric bead array, western blot/gelatin zymography and real-time RT-PCR. Functional blocking with anti-TLR4 but not with anti-TLR2 significantly downregulated TNF-α and IL-1β. However, MMP9 levels were not inhibited by toll-like receptor (TLR) blocking. Interestingly, endotoxin tolerance significantly upregulated TIMP1 relative to MMP9 and downmodulated MMP9 secretion and its enzymatic activity. These results suggest that regulatory mechanisms such as induction of endotoxin tolerance could inhibit MMP activities and could facilitate restoring host tissue homeostasis.

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

BACKGROUND

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

MATERIALS AND METHOD

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

RESULTS

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

CONCLUSION

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

Comparative gene-expression analysis of the dental follicle and periodontal ligament in humans

The human dental follicle partially differentiates into the periodontal ligament (PDL), but their biological functions are different. The gene-expression profiles of the dental follicle and PDL were compared using the cDNA microarray technique. Microarray analysis identified 490 genes with a twofold or greater difference in expression, 365 and 125 of which were more abundant in the dental follicle and PDL, respectively. The most strongly expressed genes in the dental follicle were those related to bone development and remodeling (EGFL6, MMP8, FRZB, and NELL1), apoptosis and chemotaxis (Nox4, CXCL13, and CCL2), and tooth and embryo development (WNT2, PAX3, FGF7, AMBN, AMTN, and SLC4A4), while in the PDL it was the tumor-suppressor gene WIF1. Genes related to bone development and remodeling (STMN2, IBSP, BMP8A, BGLAP, ACP5, OPN, BMP3, and TM7SF4) and wound healing (IL1, IL8, MMP3, and MMP9) were also more strongly expressed in the PDL than in the dental follicle. In selected genes, a comparison among cDNA microarray, real-time reverse-transcription polymerase chain reaction, and immunohistochemical staining confirmed similar relative gene expressions. The gene-expression profiles presented here identify candidate genes that may enable differentiation between the dental follicle and PDL.

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.

Role of PTPα in the destruction of periodontal connective tissues

IL-1β contributes to connective tissue destruction in part by up-regulating stromelysin-1 (MMP-3), which in fibroblasts is a focal adhesion-dependent process. Protein tyrosine phosphatase-α (PTPα) is enriched in and regulates the formation of focal adhesions, but the role of PTPα in connective tissue destruction is not defined. We first examined destruction of periodontal connective tissues in adult PTPα^+/+ and PTPα^−/− mice subjected to ligature-induced periodontitis, which increases the levels of multiple cytokines, including IL-1β. Three weeks after ligation, maxillae were processed for morphometry, micro-computed tomography and histomorphometry. Compared with unligated controls, there was ∼1.5–3 times greater bone loss as well as 3-fold reduction of the thickness of the gingival lamina propria and 20-fold reduction of the amount of collagen fibers in WT than PTPα^−/− mice. Immunohistochemical staining of periodontal tissue showed elevated expression of MMP-3 at ligated sites. Second, to examine mechanisms by which PTPα may regulate matrix degradation, human MMP arrays were used to screen conditioned media from human gingival fibroblasts treated with vehicle, IL-1β or TNFα. Although MMP-3 was upregulated by both cytokines, only IL-1β stimulated ERK activation in human gingival fibroblasts plated on fibronectin. TIRF microscopy and immunoblotting analyses of cells depleted of PTPα activity with the use of various mutated constructs or with siRNA or PTPα^KO and matched wild type fibroblasts were plated on fibronectin to enable focal adhesion formation and stimulated with IL-1β. These data showed that the catalytic and adaptor functions of PTPα were required for IL-1β-induced focal adhesion formation, ERK activation and MMP-3 release. We conclude that inflammation-induced connective tissue degradation involving fibroblasts requires functionally active PTPα and in part is mediated by IL-1β signaling through focal adhesions.

The expression of a nitric oxide derivative, tissue inhibitors of metalloproteinase-3, and tissue inhibitors of metalloproteinase-4 in chronic periodontitis with type 2 diabetes mellitus

Purpose

The purpose of this study was to analyze the expression of inducible nitric oxide synthases (iNOS), tissue inhibitors of metalloproteinase (TIMP)-3, and TIMP-4 in the gingival tissues of periodontal patients with or without type 2 diabetes mellitus (DM).

Methods

Depending on the patient's systemic condition and clinical criteria of the gingiva, each gingival sample was classified into one of three groups. Sixteen clinically, systemically healthy patients (group 1), 16 periodontal patients (group 2), and 16 periodontal patients with DM (group 3) were included. Tissue samples in each group were collected, prepared, and analyzed by western blotting. Quantification of the relative amount of TIMP-3, TIMP-4, and iNOS was performed.

Results

The expression levels of iNOS and TIMP-3 both increased in group 1, group 2, and group 3 in increasing order, and were significantly higher in both group 2 and group 3 as compared to group 1 (P<0.05). The expression levels of TIMP-4 increased in the same order, but significantly increased in group 2 as compared to group 1, in group 3 as compared to group 1, and group 3 as compared to group 2 (P<0.05).

Conclusions

This study demonstrated that iNOS, TIMP-3, and TIMP-4 might be involved in the progression of periodontal inflammation associated with type 2 DM. It is thought that further study of these factors can be applied practically for the diagnosis and control of periodontitis in diabetics.

The expression and regulation of matrix metalloproteinase-3 is critically modulated by Porphyromonas gingivalis lipopolysaccharide with heterogeneous lipid A structures in human gingival fibroblasts

Background

Porphyromonas gingivalis lipopolysaccharide (LPS) is a crucial virulence factor strongly associated with chronic periodontitis which is the primary cause of tooth loss in adults. It exhibits remarkable heterogeneity containing tetra-(LPS_1435/1449) and penta-(LPS₁₆₉₀) acylated lipid A structures. Human gingival fibroblasts (HGFs) as the main resident cells of human gingiva play a key role in regulating matrix metalloproteinases (MMPs) and contribute to periodontal homeostasis. This study investigated the expression and regulation of MMPs1-3 and tissue inhibitors of MMP-1 (TIMP-1) in HGFs in response to P. gingivalis LPS_1435/1449 and LPS₁₆₉₀ and hexa-acylated E. coli LPS as a reference. The expression of MMPs 1–3 and TIMP-1 was evaluated by real-time PCR and ELISA.

Results

The MMP-3 mRNA and protein were highly upregulated in P. gingivalis LPS₁₆₉₀- and E. coli LPS-treated cells, whereas no induction was observed in P. gingivalis LPS_1435/1449-treated cells. On the contrary, the expression of MMP-1 and −2 was not significantly affected by P. gingivalis LPS lipid A heterogeneity. The TIMP-1 mRNA was upregulated in P. gingivalis LPS_1435/1449- and E. coli LPS-treated cells. Next, signal transduction pathways involved in P. gingivalis LPS-induced expression of MMP-3 were examined by blocking assays. Blockage of p38 MAPK and ERK significantly inhibited P. gingivalis LPS₁₆₉₀-induced MMP-3 expression in HGFs.

Conclusion

The present findings suggest that the heterogeneous lipid A structures of P. gingivalis LPS differentially modulate the expression of MMP-3 in HGFs, which may play a role in periodontal pathogenesis.

Irsogladine maleate regulates the inflammatory related genes in human gingival epithelial cells stimulated by Aggregatibacter actinomycetemcomitans

Periodontitis is an infectious inflammatory disease. Our previous studies have revealed that irsogladine maleate (IM) regulates intercellular junctional function and chemokine secretion in gingival epithelium, resulting in the suppression of the onset of periodontal disease in a rat model. Therefore, it is plausible that IM is a promising preventive remedy for periodontal disease. In this study, to gain a better understanding of IM in gingival epithelial cells, we employed a DNA microarray analysis. More specifically, human gingival epithelial cells (HGEC) were exposed to Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) in the presence or absence of IM. Then, a human genome focus array was used. A. actinomycetemcomitans facilitated the expression of several inflammatory-related genes, including these for matrix metalloproteinase (MMP)-3, interleukin (IL)-6, and intercellular adhesion molecule-1 (ICAM-1) in HGEC, while these mRNA levels were attenuated by IM treatment. Importantly, consistent with mRNA levels, immunoblotting, immunofluorescence staining and ELISA analysis indicated that IM also abrogated the A. actinomycetemcomitans-induced increase in MMP-3, IL-6, and ICAM-1 at the protein level. In addition, inhibition of the ERK or p38 MAP kinase signaling cascade, previously reported to be disturbed by IM treatment in HGEC, clearly blocked A. actinomycetemcomitans-induced MMP-3, IL-6, or ICAM-1 protein expression. Moreover, animal study revealed that IM-pretreatment inhibited the A. actinomycetemcomitans-induced increase of ICAM-1 in gingival junctional epithelium. Taken together, these results suggested that IM can regulate inflammatory responses in HGEC by inhibiting the ERK or p38 MAP kinase signaling cascade, which may result in suppression of inflammation in gingival tissue, thereby contributing to the prevention of periodontitis.

Content of matrix metalloproteinase-8 and matrix metalloproteinase-9 in oral fluid of patients with chronic generalized periodontitis

The content of MMP-8 and MMP-9 in oral fluid of 145 patients (95 women and 50 men, 18-52 years) was measured by enzyme immunoassay. We examined 63 subjects with the intact periodontium and 82 patients with chronic generalized periodontitis (25 patients with mild disease, 45 patients with moderate disease, and 12 patients with severe disease). All patients were examined during the remission of chronic periodontitis and did not have clinical signs of associated somatic diseases. No significant differences were found in the content of MMP-8 and MMP-9 in oral fluid from periodontitis patients and subjects with the intact periodontium. The content of MMP-8 an MMP-9 in oral fluid of patients with severe periodontium was slightly higher than that in other patients and subjects with the intact periodontium. The depth of the periodontal pocket was shown to be the most reliable clinical sign for the state of periodontal tissues. A strong correlation was revealed between this criterion and MMP-9 content in oral fluid.