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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Effectiveness of scaling and root planing versus modified Widman flap on nitric oxide synthase and arginase activity in patients with chronic periodontitis

BACKGROUND

Nitric oxide (NO) is synthesized from the conversion of L-arginine to L-citrulline by NO synthase (NOS). Arginase, which is an arginine-depleting enzyme, can compete with NOS for the common substrate L-arginine and thus inhibit NO production.

OBJECTIVES

In the present study, we aimed to examine the correlation between the arginase and NOS activity in patients with chronic periodontitis and to compare the effects of scaling and root planing and modified Widman flap procedures on enzyme activity.

MATERIAL AND METHODS

The study included 13 patients diagnosed with chronic periodontitis. Using a split-mouth design, the defects showing>or=7 mm of attachment loss were treated either with scaling and root planing or with modified Widman flap. Gingival biopsies from both sites were obtained at baseline and 2 months after periodontal treatment. Immunohistochemical staining was performed for evaluating NOS expression and specific arginase activity was determined spectrophotometrically.

RESULTS

Although inflamed periodontal tissues demonstrated a strong inducible NOS (iNOS) expression at baseline, immunostaining decreased after periodontal treatment. iNOS expression intensity and the number of inflammatory cells showing iNOS expression were found to be higher in the scaling and root planing group compared to the modified Widman flap group. The specific activity of arginase was measured as 0.18+/-0.07 IU/mg protein in the modified Widman flap group and 0.25+/-0.11 IU/mg protein in the scaling and root planing group at baseline. After periodontal therapy, the enzyme level was increased to 0.68+/-0.14 IU/mg protein in the modified Widman flap and to 1.10+/-0.23 IU/mg protein in the scaling and root planing group.

CONCLUSION

This study was the first report of evaluating the involvement of the arginine-NO pathway in chronic periodontitis and this might be considered to be of value in understanding the periodontal disease mechanisms.

Effect of ultrasonic scaling on salivary lactate dehydrogenase

PURPOSE

To determine Lactate Dehydrogenase Activity (LDHA) in whole saliva in individuals with periodontal disease and the effect of ultrasonic scaling on this enzyme activity.

METHODS

A study group of 50 patients with PD (Community Periodontal Index of Treatment Needs > or = 3) was selected at random. Half of the patients (n=25) received ultrasonic periodontal treatment (Group 1). In the other 25 patients with PD the ultrasonic scaling was not performed (Group 2). A control group was selected (Group 3) consisting of 25 adults without PD (Community Periodontal Index of Treatment Needs = 0), with age and gender distribution similar to the study group. LDHA determinations were carried out with a Cobas Mira Plus II autoanalyzer pursuant to the recommendations of the French Society of Clinical Biology. A baseline determination of LDHA was carried out on all the participants and a second determination was performed 3 months later.

RESULTS

Baseline determination of LDHA was higher in patients with PD than in the control group. These differences were statistically significant (P< 0.001). LDHA was significantly reduced in patients with PD after ultrasonic scaling with respect to baseline determination (P< 0.0001). LDHA differences between Groups 2 and 3 were statistically significant (P< 0.0001), but it was not so between Groups 1 and 3.

Role of protease-activated receptor-2 in inflammation, and its possible implications as a putative mediator of periodontitis

Proteinase-activated receptor-2 (PAR2) belongs to a novel subfamily of G-protein-coupled receptors with seven-transmembrane domains. This receptor is widely distributed throughout the body and seems to be importantly involved in inflammatory processes. PAR2 can be activated by serine proteases such as trypsin, mast cell tryptase, and bacterial proteases, such as gingipain produced by Porphyromonas gingivalis. This review describes the current stage of knowledge of the possible mechanisms that link PAR2 activation with periodontal disease, and proposes future therapeutic strategies to modulate the host response in the treatment of periodontitis.

Analysis of superoxide dismutase activity levels in gingiva and gingival crevicular fluid in patients with chronic periodontitis and periodontally healthy controls

OBJECTIVES

Superoxide dismutase (SOD) is an antioxidant enzyme that acts against superoxide, an oxygen radical, released in inflammatory pathways and causes connective tissue breakdown. In this study, SOD activities in gingiva and gingival crevicular fluid (GCF) from patients with chronic periodontitis (CP) and periodontally healthy controls were compared.

MATERIAL AND METHODS

Twenty-six CP patients and 18 controls were studied. In patients, teeth with moderate-to-severe periodontal breakdown and > or =5 mm pockets that required full-thickness flap surgery in the right or left maxillary quadrant, and in controls, teeth scheduled for extraction for orthodontic reasons were studied. After the clinical measurements (probing depth, clinical attachment level, gingival index, gingival bleeding index, plaque index), GCF samples were collected. Tissue samples were harvested from the same teeth, during flap operation in patients and immediately after tooth extraction in controls. SOD activities were spectrophotometrically assayed. The results were statistically analysed.

RESULTS

Gingival SOD activity was significantly higher in the CP group than in controls (p<0.05). No significant difference was found in GCF SOD activity between the groups (p>0.05). Correlations between gingival and GCF SOD activities were not statistically significant in CP and control groups (p>0.05).

CONCLUSION

In CP, SOD activity seems to increase in gingiva, probably as a result of a higher need for SOD activity and protection in gingiva in CP than in periodontal health, while not significantly changing in GCF, suggesting a weak SOD activity in GCF in periodontal disease state. The weak correlation between gingival and GCF SOD activities suggests distinct actions of these SODs.

Clues for new therapeutics in osteoporosis and periodontal disease: new roles for lipoxygenases?

Lipoxygenase (LOX) pathways are well appreciated for their ability to regulate key events contributing to the cardinal signs of inflammation. Recent evidence indicates that LOX genes are associated with osteoporosis. Also, overexpression of the 15-LOX Type 1 in transgenic rabbits leads to a reduced inflammatory phenotype and protection from periodontal disease, as well as atherosclerosis. Osteoporosis and inflammation-associated bone degradation, such as periodontitis, affect many individuals worldwide and are known to have pathogenesis that involves local mediators via communication between osteoclasts and osteoblasts during osteogenesis. Evidence has emerged indicating that LOX gene expression is associated with reduced bone strength in murine models of osteoporosis. Overexpression of the 15-LOX gene and its products, such as lipoxins, confers endogenous anti-inflammation. This article discusses the recent findings that may link aberrant LOX pathway expression in these diseases, suggesting new avenues for therapeutic approaches via activation of endogenous pathways for resolution of local inflammation.

Matrix metalloproteinases (MMPs) in oral diseases

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

Analysis of the MMP-9 (C-1562 T) and TIMP-2 (G-418C) gene promoter polymorphisms in patients with chronic periodontitis

BACKGROUND

Matrix metalloproteinases (MMP)-9 is an important member of the matrix metalloproteinase family. A functional polymorphism has been described in the promoter region of the human MMP-9 gene. A C-to-T base exchange at -1562 creates two different alleles, and the C/T and T/T genotypes promote high activity of the MMP-9 gene promoter, increasing the risk for inflammatory diseases. The metalloproteinase-2 tissue inhibitor (TIMP-2) regulates the activity of MMPs in the extracellular matrix, and a polymorphism at the -418 position of the TIMP-2 gene promoter has been found in a Sp-1 binding site. In this study we have investigated the association between the above-mentioned polymorphisms and chronic periodontitis severity.

METHODS

Genomic DNA from oral mucosa of 100 subjects was amplified by polymerase chain reaction and analysed by restriction endonuclease digestion. The significance of the differences in observed frequencies of polymorphisms in moderate and severe disease and healthy groups was assessed by chi(2) test (p<0.05).

RESULTS

No association was observed between the polymorphism in the promoter region of MMP-9 (p=0.6693) and chronic periodontitis. The analysis of TIMP-2 showed that the G/G genotype was found at a frequency of 99%.

CONCLUSION

The results show that the polymorphism in the promoter region of MMP-9 gene is not associated with chronic periodontitis. The high frequency of GG genotype in the TIMP-2 gene promoter in the population studied did not allow any conclusion regarding its effect on chronic periodontitis.

Secretory function of neutrophilic leukocytes of the patients with periodontal diseases

Aim of study was to examine periodontal status among 20 44 year old patients and to study the secretory function of peripheral venous blood neutrophilic leukocytes (NL) exposed to various antigens and alkaline phosphatase (AP) activity in gingival crevicular fluid (GCF) in patients suffering from gingivitis and periodontitis. Clinically were determined Russell's periodontal index (PI). Secretory function of NL affected by opsonized zymosane, non-opsonized E. coli was examined in 77 patients with gingivitis and periodontitis, and in 35 donors, free of internal diseases, by means of beta-glucuronidase (beta-GD), lysozyme (LZ). NL secreted higher levels of beta-GD in incubation medium in patients with periodontitis (p < or = 0.001) subject to degree of periodontal lesion. NL affected by various antigens secreted higher levels of LZ into non-cellular matrix in patients with gingivitis and periodontitis comparing to control environment in analogous groups. Data obtained from this study suggest that in patients with periodontitis response of NL to bacterial stimuli is specific and subject to the degree of periodontal lesion. Our study showed a significant difference of AP activity in GCF subject to pocket depth and degree of periodontal lesion. Once NL are exposed to corpuscules prone to phagocytosis, an increase in secretion of beta-GD and LZ can be explained by overall increase in secretion of NL lysosomic enzymes, thus disclosing the mechanism of inflammatory periodontal tissue damage.

Polymorphisms in genes coding for enzymes metabolizing smoking-derived substances and the risk of periodontitis

OBJECTIVES

Although the direct cause for periodontitis is oral bacterial infection, its progression depends upon genetic and environmental factors. Smoking, one of the environmental factors, is a risk factor for the development and severity of periodontitis. Therefore, individual susceptibility to periodontitis may be influenced by the polymorphisms of genes coding for enzymes metabolizing tobacco-derived substances. The object of this study is to investigate roles of genetic polymorphisms of these metabolizing enzymes in the risk for periodontitis.

MATERIAL AND METHODS

We investigated three important enzymes: cytochrome P450 (CYP) 1A1, CYP2E1 and glutathione S-transferase (GST) M1, involved in the metabolic activation and detoxification of tobacco-derived substances. The prevalence of the polymorphisms of these genes was examined in 115 patients with periodontitis as well as in 126 control subjects.

RESULTS

Significantly increased risk for periodontitis was observed for subjects with the polymorphic CYP1A1 m2 allele (odds ratio (OR)=2.3, 95% confidence interval (CI)=1.2-4.4). A significant risk increase for periodontitis associated with the GSTM1 allele was observed (OR=2.1, 95% CI=1.3-3.6). However, no association was observed between the CYP2E1 Pst1 polymorphism and risk for periodontitis (OR=1.3, 95% CI=0.6-2.5).

CONCLUSION

These results suggest that the GSTM1 and CYP1A1 polymorphisms may play an important role in risk for periodontitis.

Correlation of peri-implant health and myeloperoxidase levels: a cross-sectional clinical study

OBJECTIVES

At present, there are no diagnostic tools that permit early detection of peri-implantitis. The purpose of this cross-sectional study was to evaluate the correlation of myeloperoxidase (MPO) levels with traditional periodontal clinical parameters around dental implants including peri-implant pocket probing depth (PPD), gingival index (GI) and bleeding on probing (BOP), since MPO has been associated with destruction of periodontal tissues.

MATERIAL AND METHODS

Twenty-four healthy adult volunteers (9 men and 15 women) with 64 Ankylos Biofunctional implants (DentsplyFriadent, Mannheim, Germany) were recruited from Tallinn Dental Clinic. Biochemical and clinical parameters evaluated were the following ones: the level of MPO in the peri-implant sulcus fluid (PISF) (an analog for gingival crevicular fluid in natural teeth), PPD (mm), GI (0,1,2 or 3), and BOP (0 or 1).

RESULTS AND CONCLUSION

In comparison to the clinically healthy implants, total amounts of MPO were significantly higher in PISF collected around implants with inflammatory lesions. In addition, the levels of MPO were correlated with the clinical parameters. The results confirm the similarity of the inflammatory response of tissues surrounding implants and natural teeth, and suggest that MPO could be promising marker of inflammation around dental implants.

Proinflammatory Cytokines Induce Proteinase 3 as Membrane-Bound and Secretory Forms in Human Oral Epithelial Cells and Antibodies to Proteinase 3 Activate the Cells through Protease-Activated Receptor-2

Anti-neutrophil cytoplasmic Abs targeting proteinase 3 (PR3) have been detected in relation to a wide range of inflammatory conditions such as periodontitis, and interaction of anti-PR3 Abs with endothelial and epithelial cells provokes cell activation, although the underlying mechanism has been unclear. The present study showed that human oral epithelial cells expressed PR3 mRNA after treatment with proinflammatory cytokines such as IL-1alpha, TNF-alpha, IFN-alpha, IFN-beta, and IFN-gamma. A 29-kDa PR3 was expressed on the cell surface and released into culture supernatants by the cells upon stimulation with these cytokines. The membrane and supernatant fractions of oral epithelial cells exhibited enzymatic activity, which was inhibited by serine proteinase inhibitors, but not by a cysteine proteinase inhibitor or secretory leukocyte protease inhibitor. Addition of anti-PR3 Abs to cytokine-primed oral epithelial cells in culture induced remarkable secretion of IL-8 and monocyte chemoattractant protein 1 and aggregation of PR3 on the cells. RNA interference targeted to protease-activated receptor-2 mRNA and intracellular Ca2+ mobilization assays revealed that anti-PR3 Abs activated the epithelial cells through protease-activated receptor-2, a family of G protein-coupled receptors. The anti-PR3 Ab-mediated cell activation was completely abolished by RNA interference targeted to PR3 mRNA and by inhibition of phospholipase C and NF-kappaB. Immunohistochemistry showed that inflamed oral epithelium actually expresses PR3 protein. These results suggest that oral epithelial cells express functional PR3 in the inflamed sites and respond to anti-PR3 Abs detected in diseased sera, and that these mechanisms may actively participate in the inflammatory process, including periodontitis.

Role of the activation of the nuclear enzyme poly(ADP-ribose) polymerase in the pathogenesis of periodontitis

We have investigated the role of the activation of nuclear poly(ADP-ribose) polymerase (PARP) enzyme, a mediator of downstream nitric oxide toxicity, using a combined approach of pharmacological inhibition and genetic disruption in a ligature-induced-periodontitis model in rats and mice. Immunohistochemical analysis revealed significantly increased poly(ADP-ribose) nuclear staining (indicative of PARP activation) in the subepithelial connective tissue of the ligated side compared with the non-ligated side. Ligation-induced periodontitis resulted in marked plasma extravasation in the gingivomucosal tissue and led to alveolar bone destruction compared with the non-ligated side, as measured by the Evans blue technique and by videomicroscopy, respectively. PARP inhibition with PJ34, as well as genetic PARP-1 deficiency, significantly reduced the extravasation and the alveolar bone resorption of the ligated side compared with controls. Thus, PARP activation contributes to the development of periodontal injury. Inhibition of PARP may represent a novel host response modulatory approach for the therapy of periodontitis.

Tissue plasminogen activator (t-PA) and placental plasminogen activator inhibitor (PAI-2) in gingival crevicular fluid from patients with Papillon-Lefevre syndrome

OBJECTIVES

Numerous patients with Papillon-Lefèvre syndrome (PLS) express a severe periodontal inflammation that results in premature loss of deciduous and permanent teeth. The plasminogen activating (PA) system is involved in physiological and pathological processes including epithelial healing, extracellular proteolysis and local inflammatory reactions. The aim of the study was to explore a possible role of the PA system in patients with PLS.

MATERIAL AND METHODS

Samples of gingival crevicular fluid (GCF) were collected from areas with gingival infection in 20 patients with PLS and in 20 healthy controls. The concentration of tissue plasminogen activator (t-PA) and inhibitor (PAI-2) was measured with ELISA.

RESULTS

The median level of PAI-2 was significantly higher (p < 0.01) in PLS patients than in the controls, while the median value of t-PA did not differ between the groups. No difference in t-PA or PAI-2 levels was found regarding age, gender or presence of active periodontal disease.

CONCLUSION

The findings indicate an atypical activity of the PA system with a disturbed epithelial function in PLS patients, suggesting that the periodontal destruction seen in patients with PLS is secondary to a hereditary defect in the defense system.

Matrix metalloproteinase-1 and -3 gene promoter polymorphisms in Japanese patients with periodontitis

BACKGROUND/AIMS

Matrix metalloproteinase (MMP)-1 and MMP-3 have important roles in the connective tissue remodelling and destruction processes in periodontitis. MMP-1 1G/2G (-1607) and MMP-3 5A/6A (-1171) polymorphisms have been identified and appear to influence the transcription of the genes. The aim of this study was to investigate whether these gene promoter polymorphisms were associated with the susceptibility to periodontitis.

MATERIAL AND METHODS

Genomic DNA was obtained from 37 generalised aggressive, 205 slight-to-severe generalised chronic-periodontitis patients and 142 healthy subjects. All subjects were non-smoking Japanese. We genotyped by using TaqMan PCR assay. The statistics were analysed by chi2-test.

RESULTS

We found no significant differences in genotype distributions, allele frequencies, carriage rates and haplotype frequencies in the MMP-1 and the MMP-3 gene promoter polymorphisms among all groups. The distributions of MMP-1 and MMP-3 genotypes in our study were different from those of previously reported in Caucasians or Brazilians, but consistent with previously reported in Japanese.

CONCLUSION

Our data did not support the hypothesis that MMP-1 and/or MMP-3 gene promoter polymorphisms influenced the susceptibility to periodontitis in Japanese patients, indicating MMP-1 and MMP-3 expressions were regulated by complex processes such as cytokine network in periodontal disease rather than gene polymorphisms.

Association of ALDH(2) genotypes and alcohol consumption with periodontitis

There is little information regarding the association between alcohol consumption and periodontitis risk. We assessed whether alcohol consumption and ALDH(2) genotypes were associated with periodontitis. Subjects' lifestyle was examined by a self-administered questionnaire, and the percentage of pocket depths > or = 3.5 mm was used as a periodontal parameter. ALDH(2) genotypes were determined with the use of a PCR/RFLP method. Multiple logistic analyses showed that alcohol consumption was significantly associated with periodontitis, and its odds ratio was 1.98. There was no significant relationship between periodontal status and ALDH(2) genotypes. However, ALDH(2)*1/*2 subjects who consumed > or = 33 g/day of alcohol had a significantly greater percentage of pocket depths > or = 3.5 mm than those whose daily consumption was lower, while there was no significant difference in periodontal status associated with alcohol consumption in ALDH(2)*1/*1 subjects. Our results suggest that alcohol consumption may be a risk indicator for periodontitis in ALDH(2)*1/*2 subjects who consume larger amounts of alcohol.

The short-term effectiveness of non-surgical treatment in reducing protease activity in gingival crevicular fluid from chronic periodontitis patients

OBJECTIVES

The aim of this study was to evaluate the short-term effect of non-surgical periodontal treatment on protease activity in gingival crevicular fluid (GCF) of patients with chronic periodontitis.

MATERIAL AND METHODS

After clinical examination, in which pocket probing depth, probing attachment level, plaque and bleeding indices were recorded, gingival fluid samples from 21 chronic periodontitis patients were collected from gingivitis (GP) and periodontitis (PP) sites with an intracrevicular washing method. Samples were taken in the same way from a group of patients with gingivitis alone (GG). The periodontitis patients received non-surgical periodontal treatment and were re-evaluated 30 days later. We compared elastase and collagenase activities before and after treatment. The former activity was measured with a low-weight substrate (S-2484) and inhibited by alpha-1-antitrypsin. Matrix-metalloproteinase-8 (MMP-8) was measured with an ELISA and collagenolytic activity with fluorescein-conjugated collagen type I as substrate.

RESULTS

All clinical parameters showed a significant improvement after treatment (p<0.05) which was accompanied by a significant reduction in the values of total elastase activity, free elastase, MPP-8 and collagenolytic activity in both GP and PP sites (p<0.05). However, the latter sites continued to have higher levels of MMP-8 and collagenolytic activity than the former ones after treatment. The free elastase activity and the proportion of free elastase in GP and PP samples after treatment remained higher than in untreated GG samples.

CONCLUSION

This study shows that the clinical improvements after non-surgical treatment are accompanied by reductions in protease and neutrophil activities.

Genetic variations in the matrix metalloproteinase-1 promoter and risk of susceptibility and/or severity of chronic periodontitis in the Czech population

OBJECTIVES

Matrix metalloproteinase-1 (MMP-1) is a potent enzyme degrading extracellular matrix that was implicated in the pathogenesis of chronic periodontitis. Therefore, the aim of our study was to examine the association between three promoter polymorphisms of the MMP-1 gene and chronic periodontitis susceptibility and/or severity in a Czech population.

MATERIALS AND METHODS

A total of 329 Caucasian subjects were enrolled in this study. They were 133 patients with mild to severe chronic periodontitis and 196 unrelated control subjects. MMP-1 promoter polymorphisms (-1607 1G/2G, -519A/G, and -422A/T) were genotyped using standard polymerase chain reaction-restriction fragment length product methods.

RESULTS

Genotype analysis of the three single nucleotide polymorphisms across 27 different combinations showed significant association with chronic periodontitis (p<0.05). Analyses of individual polymorphisms showed no differences in distribution of the -519A/G and -422A/T variants between periodontitis and control groups. However, a trend to increased frequency of the -1607 1G allele was observed in patients with chronic periodontitis compared with the controls (p=0.054). When the groups were further stratified by smoking status, the 1G allele was associated with chronic periodontitis among non-smokers but not among smokers (p=0.033). On the contrary, the distribution of genotype frequencies of the MMP-1 -422A/T polymorphism was different between the patient and control smokers with respect to heterozygotes (73.91% versus 50.91%; p=0.017).

CONCLUSIONS

Our results demonstrate that the polymorphisms in the MMP-1 promoter may have only a small effect on the etiopathogenesis of chronic periodontitis.

Matrix Metalloproteinase-2 May Be Involved With Increased Bone Loss Associated With Experimental Periodontitis and Smoking: A Study in Rats

BACKGROUND

Smoking has been associated with periodontitis severity and is considered a risk factor for its development. It has been reported that matrix metalloproteinase (MMP) produced by host cells plays a major role in periodontal tissue destruction. Thus, the present study tested, in rats, the hypothesis that local increased levels of MMP-2 would be associated with the enhanced periodontitis-related bone loss after intermittent cigarette smoke inhalation (CSI).

METHODS

Twenty-seven adult male Wistar rats were used. A ligature was placed around one of the mandibular first molars of each animal and they were randomly assigned to the following control (N = 13) or CSI (N = 14) group. Sixty days later, the animals were sacrificed, the gingival tissues harvested, and the specimens processed for decalcified sections. Extracts from the gingival tissues were prepared and assayed for MMP-2 expression.

RESULTS

Intergroup comparisons (unligated sites) showed that CSI might directly affect alveolar bone (0.16 +/- 0.03 mm2 versus 0.24 +/- 0.09 mm2 for non-smokers and smokers, respectively; P = 0.001). Moreover, CSI significantly enhanced bone loss resulting from experimental periodontitis (0.64 +/- 0.36 mm2 versus 1.50 +/- 0.50 mm2 for non-smokers and smokers, respectively; P<0.05). In addition, zymography demonstrated that CSI also enhanced both MMP-2 levels and activity in the gingival tissues around ligated teeth.

CONCLUSION

Within the limits of the present investigation, it can be assumed that the effect of CSI on MMP-2 levels and activity may account for the increased periodontitis progression rate observed in smokers.

A molecular defect in intracellular lipid signaling in human neutrophils in localized aggressive periodontal tissue damage

Host defense mechanisms are impaired in patients with congenital neutrophil (polymorphonuclear neutrophils (PMN)) defects. Impaired PMN chemotaxis is observed in localized aggressive periodontitis (LAP), a familial disorder characterized by destruction of the supporting structures of dentition. In the present studies, we sought evidence for molecular events underlying this aberrant human PMN phenotype. To this end, PMN transendothelial migration and superoxide anion generation were assessed with LAP patients and asymptomatic family members, as well as patients with other chronic mucosal inflammation. PMN from LAP patients showed decreased transmigration across vascular endothelial monolayers (18 +/- 12% of control, n = 4) and increased superoxide anion generation (358 +/- 37%, p = 0.003). Gene expression was analyzed using oligonucleotide microarrays and fluorescence-based kinetic PCR. cDNA microarray and kinetic-PCR analysis revealed diminished RNA expression of leukocyte-type diacylglycerol (DAG) kinase alpha in PMN from LAP patients (4.6 +/- 1.7 relative units, n = 6, p = 0.007) compared with asymptomatic individuals (51 +/- 27 relative units, n = 7). DAG kinase activity was monitored by DAG phosphorylation and individual DAG molecular species were quantified using liquid chromatography and tandem mass spectrometry-based lipidomics. DAG kinase activity was also significantly decreased (73 +/- 2%, p = 0.007) and correlated with increased accumulation of 1,2-diacyl-sn-3-glycerol substrates (p = 0.01). These results implicate defects in both PMN transendothelial migration and PMN DAG kinase alpha signaling as disordered functions in LAP. Moreover, they identify a potential molecular lesion in PMN signal transduction that may account for their aberrant responses and tissue destruction in this disease.

Interleukin-4 suppresses IL-1-induced expression of matrix metalloproteinase-3 in human gingival fibroblasts

BACKGROUND

In periodontitis, matrix metalloproteinase-3 (MMP-3, stromelysin 1) is present at increased levels in active disease sites compared to inactive or healthy sites, and the levels are correlated with clinical parameters and associated with progression of the disease. Interleukin (IL)-4 has been shown in human skin and synovial fibroblasts and articular chondrocytes to suppress IL-1-induced expression of MMP-3, but this has not been shown in human gingival fibroblasts. The objective of this study is to determine the effects of IL-4 on the IL-1-induced expression of MMP-3 in human gingival fibroblasts isolated from patients with periodontitis.

METHODS

Northern blot analysis was performed to determine the effects of IL-4 on the IL-1 induction of MMP-3 mRNA. MMP-3 protein levels were determined by enzyme-linked immunosorbent assay (ELISA), and prostaglandin E2 (PGE2) levels were measured by enzyme immunoassay (EIA). DNA binding of activator protein (AP)-1 and nuclear factor (NF)-kappaB was assessed by electrophoretic mobility shift assay (EMSA).

RESULTS

Northern blot analysis revealed that co-incubation of gingival fibroblasts with IL-1 and IL-4 resulted in a significant decrease in MMP-3 mRNA levels compared to IL-1 alone, with a concomitant decrease in protein levels. This inhibition is dose-dependent, and is apparent as early as 3 hours after stimulation. IL-1-induced production of PGE2 was not affected in four of six cultures isolated from different individuals. Addition of exogenous PGE2 had no effect on the suppressive effects of IL-4. DNA binding of transcription factors AP-1 and NF-kappaB was not affected by IL-4.

CONCLUSIONS

IL-4 inhibits the IL-1 induction of MMP-3 in human gingival fibroblasts isolated from patients with periodontitis. This effect is independent of PGE2 and is not due to inhibition of the DNA binding activity of known transcription factors binding to the MMP-3 promoter.

The effect of adjunctive low-dose doxycycline therapy on clinical parameters and gingival crevicular fluid matrix metalloproteinase-8 levels in chronic periodontitis

BACKGROUND

Low-dose doxycycline (LDD) is recognized to have non-antimicrobial properties that can therapeutically modulate the host response. The aim of the present randomized, double-blind, placebo-controlled, parallel-arm study was to examine the effectiveness of LDD in combination with non-surgical periodontal therapy, compared to non-surgical periodontal therapy alone, on gingival crevicular fluid (GCF) matrix metalloproteinase-8 (MMP-8) levels and clinical parameters over a 12-month period in patients with chronic periodontitis.

METHODS

GCF samples were collected, and clinical parameters including probing depth (PD), clinical attachment level, gingival index (GI), and plaque index were recorded. Thirty chronic periodontitis patients were randomized either to a low-dose doxycycline (LDD) or placebo group. The LDD group received low-dose doxycycline (20 mg) b.i.d. for 3 months plus scaling and root planing (SRP), while the placebo group was given placebo capsules b.i.d. for 3 months plus SRP. The patients were evaluated every 3 months during the 12-month study period. At each visit, all clinical measurements and GCF sampling were repeated. GCF MMP-8 levels were determined by a time-resolved immunofluorescence assay. Intragroup comparisons were tested by the Friedman test followed by Wilcoxon signed-rank test to analyze significance of changes over time. The Mann-Whitney test was used to determine differences between the LDD and placebo groups.

RESULTS

Significant improvements were observed in all clinical parameters in both groups over the 12-month period (P < 0.0125). The LDD group showed a significantly greater reduction in mean PD scores at 9 and 12 months and in mean GI scores at all time points than the placebo group (P < 0.05). From baseline to 12 months, GCF MMP-8 levels were significantly reduced in both groups (P < 0.0125). The GCF MMP-8 level in the LDD group was significantly lower than that of the placebo group at 6 months (P < 0.05).

CONCLUSIONS

The present results indicate that low-dose doxycycline therapy in combination with scaling and root planing can reduce GCF MMP-8 levels and improve clinical periodontal parameters in patients with chronic periodontitis. These results provide additional information about the usefulness of low-dose doxycycline therapy as an adjunct to non-surgical periodontal therapy in the long-term management of periodontal disease. The effectiveness and course of low-dose doxycycline therapy can be monitored conveniently by assessing GCF MMP-8 levels.

[Effects of baicalin on the expression of pro-MMP-1 and MMP-3 in human gingival fibroblasts and periodontal ligament cells]

OBJECTIVE

To investigate the influence of baicalin on the IL-1beta induced pro-MMP-1 in HGF and the effects of baicalin on MMP-3 expression in periodontal ligament cells (PDLCs).

METHODS

The amount of secreted pro-MMP-1 and MMP-3 expression was detected by ELISA and cell immunochemistry.

RESULTS

(1) The amount of secreted pro-MMP-1 (3.333 +/- 0.123) microg/L increased significantly following 1 microg/L of IL-1beta, compared with control group (1.960 +/- 0.180) microg/L. Addition of baicalin to cell culture medium for 1 hour following IL-1beta decreased pro-MMP-1 secretion in a dose-dependent manner in the range of 10 approximately 1,000 microg/L. (2) 1 microg/L IL-1beta could significantly stimulate the synthesis and secretion of MMP-3 in PDLCs. (3) The baicalin could not interfere the synthesis of MMP-3, but could inhibit the release of MMP-3 from PDLCs.

CONCLUSIONS

Baicalin could inhibit the secretion of pro-MMP-1 and MMP-3 expression in IL-1beta induced HGF and PDLCs, which suggests that baicalin may play an important role in preventing and treating periodontal disease.

In situ detection of matrix metalloproteinase-9 (MMP-9) in gingival epithelium in human periodontal disease

BACKGROUND AND OBJECTIVE

As the periodontal lesion develops, the junctional epithelium migrates apically in conjunction with the dissolution of the most coronal Sharpey's fibers. Because matrix metalloproteinase-9 (MMP-9) has been identified in migrating epithelial cells and invading tumors, we propose that this enzyme is produced by gingival keratinocytes in advanced periodontal lesions.

METHODS

To test this idea, biopsies of inflamed gingival tissues were obtained from patients with advanced periodontitis. Healthy gingival tissue samples were utilized as controls. The presence and activity of MMP-9 was evaluated by combining indirect immunofluorescence of gingival tissue samples and gelatin zymography of gingival epithelium separated from connective tissue.

RESULTS AND CONCLUSIONS

The staining pattern showed the presence of MMP-9 in junctional and pocket gingival epithelial cells, polymorphonuclear neutrophils (PMNs) and as a scattered deposit along connective tissues of periodontitis-affected gingival tissues. Gelatin zymography permitted the identification of pro-MMP-9 in surcular/pocket epithelium derived from inflamed gingival tissues. Lower levels of MMP-9 were detected in epithelium not exposed to inflammation. These observations suggest a role for MMP-9 in gingival epithelial response to periodontal infection.