Expression of prostaglandin E synthases in periodontitis immunolocalization and cellular regulation

The inflammatory mediator prostaglandin E(2) (PGE(2)) is implicated in the pathogenesis of chronic inflammatory diseases including periodontitis; it is synthesized by cyclooxygenases (COX) and the prostaglandin E synthases mPGES-1, mPGES-2, and cPGES. The distribution of PGES in gingival tissue of patients with periodontitis and the contribution of these enzymes to inflammation-induced PGE(2) synthesis in different cell types was investigated. In gingival biopsies, positive staining for PGES was observed in fibroblasts and endothelial, smooth muscle, epithelial, and immune cells. To further explore the contribution of PGES to inflammation-induced PGE(2) production, in vitro cell culture experiments were performed using fibroblasts and endothelial, smooth muscle, and mast cells. All cell types expressed PGES and COX-2, resulting in basal levels of PGE(2) synthesis. In response to tumor necrosis factor (TNF-α), IL-1β, and cocultured lymphocytes, however, mPGES-1 and COX-2 protein expression increased in fibroblasts and smooth muscle cells, accompanied by increased PGE(2), whereas mPGES-2 and cPGES were unaffected. In endothelial cells, TNF-α increased PGE(2) production only via COX-2 expression, whereas in mast cells the cytokines did not affect PGE(2) enzyme expression or PGE(2) production. Furthermore, PGE(2) production was diminished in gingival fibroblasts derived from mPGES-1 knockout mice, compared with wild-type fibroblasts. These results suggest that fibroblasts and smooth muscle cells are important sources of mPGES-1, which may contribute to increased PGE(2) production in the inflammatory condition periodontitis.

Alpha-1-antitrypsin deficiency and periodontitis, a pilot study

The aim of this study was to investigate if periodontal parameters and elastase in gingival crevicular fluid (GCF) are different in alpha-1-antitrypsin deficient (AATD) subjects compared to subjects with normal AAT level. Thirty subjects were included, 20 of whom with severe AATD, phenotype PiZZ. Ten AATD subjects suffered from chronic obstructive pulmonary disease (COPD, group 1) and 10 were asymptomatic (group 2). Ten control subjects, phenotype PiMM, (group 3) were recruited from a public dental clinic. The examination comprised of sampling of GCF, Gingival Index (GI), Plaque Index (PlI), probing pocket depth (PPD) and radiography. GCF was collected with paper strips (Periopaper). Plasma AAT concentration was measured by nephelometry and AAT in GCF with ELISA. Elastase activity and protein in GCF were determined by spectrophotometry. The mean values for GI, PlI, PPD and the radiological measurements did not show any statistically significant differences between the groups. AAT in plasma and GCF demonstrated very low values in groups 1 and 2 with no significant difference between these groups but a statistical difference in comparison with group 3. Elastase in GCF did not show any difference between the three groups. In conclusion, neither the periodontal parameters nor the elastase in GCF were different in AATD subjects, phenotype PiZZ, when compared to subjects with normal AAT level, phenotype PiMM, in this material.

Clinical studies on the management of periodontal diseases utilizing subantimicrobial dose doxycycline (SDD)

Periodontitis, the most common chronic inflammatory condition known to mankind, is a disease that results in the destruction of tooth supporting tissues. Periodontitis is initiated by a bacterial biofilm on the tooth surface below the gingival margin. Until fairly recently it was assumed that the bacteria were the primary cause of tissue destruction, however, a large body of research has revealed that it is the patient's immune response that is actually responsible for the majority of the breakdown of tooth supporting tissues. Contemporary thinking suggests that successful, long term management of chronic periodontitis may combine both local mechanical and antimicrobial strategies to reduce the microbial bio-burden along with modulation of the host, patient's excessive, immuno-inflammatory response to the bacterial exposure known as host modulatory therapy (HMT). Based on extensive literature documenting the enzymatic inhibition and related anti-inflammatory properties of the tetracyclines, a new drug was developed as a host modulatory agent and approved by the United States Food and Drug Administration (FDA) for use as an adjunct to conventional scaling and root planing for the treatment of chronic periodontitis. A subantimicrobial dose of doxycycline (SDD) at 20 mg (Periostat(®)) has been found to be a safe and effective adjunct when taken twice daily for at least 3 months and up to 24 months in randomized placebo controlled clinical trials. Periostat(®) is currently the only FDA approved inhibitor of the matrix metalloproteinases implicated in the plaque-induced pathologic degradation of connective tissue collagen of the periodontal supporting structures. This review paper begins with a brief description of the disease process known as periodontitis followed by an extensive review of the Phase I-IV clinical trial data that established the safety and efficacy of sub-antimicrobial dose doxycycline (SDD) as an adjunct to scaling and root planing for the treatment of periodontitis.

Clinical and biochemical efficacy of minocycline in nonsurgical periodontal therapy: a randomized controlled pilot study

The present study evaluated the effects of systemic minocycline on clinical and biochemical parameters of chronic periodontitis, which is a common inflammatory disorder of the periodontium initiated by the presence of bacteria in the gingival sulcus. Besides nonsurgical periodontal therapy, 20 individuals received minocycline systemically while another 20 subjects received placebo capsules for 2 weeks. Plaque index (PI), sulcus bleeding index (SBI), probing depth (PD), and relative attachment level (RAL) were measured and gingival crevicular fluid (GCF) samples were obtained at baseline and first, third, and sixth months. Matrix metalloproteinase-8 (MMP-8) and prostaglandin E₂ (PGE₂) levels were analyzed by enzyme immunoassay method. Significant improvements in all parameters in both groups were recorded. In the minocycline group, changes in PI and SBI were significantly greater only at first month, whereas reductions in PD, RAL, MMP-8, and PGE₂ levels were greater at all times. MMP-8 and PGE₂ exhibited positive correlations with SBI, PD, and each other. Minocycline demonstrated clinical benefit for periodontal therapy and provided further improvements on inflammatory mediators promising a host-modulating capacity.

Differential gene and protein expression of tissue inhibitors of metalloproteinases (TIMP)-3 and TIMP-4 in gingival tissues from drug induced gingival overgrowth

OBJECTIVES

The purpose of this study was to analyse mRNA expression and protein localization of tissue inhibitors of metalloproteinases (TIMP)-3 and TIMP-4 in gingival tissues removed from drug (calcium-channel blocker) induced gingival overgrowth and periodontitis patients.

DESIGN

Employing RT-PCR, we evaluated TIMP-3 and TIMP-4 mRNA levels of 20 human gingival tissue samples taken from patients suffering gingival overgrowth (GO) and periodontitis (P). Then, using immunohistochemistry we investigated the TIMP-3 and TIMP-4 protein localization of five sample tissues from each group.

RESULTS

TIMP-4 mRNA levels in GO-gingiva tended to be lower than in P-gingiva but the results differed little (p = 0.22). Varying degrees of inflammation in the protein localization of TIMP-3 and TIMP-4 were found. TIMP-4 immunoreactivity (IR) was weak in the endothelial cells, fibroblasts, epithelial basal and parabasal cells while the degree of inflammation differed as well. TIMP-3 and TIMP-4 IR in inflammatory cells, including lymphocytes, plasma cells, and macrophages, were faint and intense respectively. For P-gingiva, both TIMP-3 and TIMP-4 IR expression was weak in the endothelial cells, fibroblasts, basal and parabasal epithelial layers. Expression of TIMP-3 was faint in the inflammatory cells, whereas TIMP-4 IR was strong.

CONCLUSION

Our findings suggest that TIMP-3 and TIMP-4 expression differs in GO and P-gingival tissues, both of which are potentially involved in pathogenesis.

Lysozyme and microbiota in relation to gingivitis and periodontitis

BACKGROUND

The aim of this study was to investigate associations between the immune component of the oral cavity, lysozyme, in gingival crevicular fluid and unstimulated saliva, and colonization dynamics of periodontopathogenic bacteria from supra- and subgingival plaque samples in patients with gingivitis or periodontitis.

MATERIAL/METHODS

Lysozyme in crevicular fluid and unstimulated saliva, and bacteria in supra- and subgingival plaque samples were assessed in 84 samples from 28 patients with gingivitis, 96 samples from 32 patients with periodontitis, and 72 samples from 24 donors with intact periodontium and free of internal disease. Lysozyme activity was determined spectrophotometrically. The micro-IDent plus assay was used to detect 6 periodontopathogenic bacteria plaque samples.

RESULTS

Lysozyme activity in crevicular fluid in the gingivitis and periodontitis groups was significantly greater than that in the donor group, but lysozyme activity in unstimulated saliva was less than that in the donor group. Peptostreptococcus micros, Fusobacterium periodontium and Campylobacter rectus were predominant in subgingival plaque samples in the periodontitis group compared to the donor group (P<0.001), and Eubacterium nodatum and Eikenella corrodens were predominant in the gingivitis group compared to the donor group (P<0.001).

CONCLUSIONS

Lysozyme activity in crevicular fluid and in unstimulated saliva correlated with periodontal pocket depth in donors and in patients with gingivitis or periodontitis (specificity and sensitivity were both 100%). These findings indicate that infection with P. micros, F. periodontium, E. nodatum, E. corrodens, and C. rectus may be an important indicator of inflammatory periodontal disease development.

Acid-base status and fructose diphosphatase activity in rats exposed to fluoride and induced periodontitis

This study was conducted to evaluate acid-base status and fructose diphosphatase (FDPase) activity in 40 (4 groups of 10) male Wistar rats. One group of rats was left untreated as control, fed a standard diet, and given distilled water. Periodontitis model induced with 5 mg/kg NH4Cl (group 1), exposed to sodium fluoride (NaF) at the concentration 5 mg/l (group 2), exposed to NaF (5 mg/l) and supplemented with minerals and vitamins (group 3). At the termination of experimental period (30 days) the pH and pCO2 value of arterial blood were analysed. Then, the FDPase activity in the hemogenized heart, kidney liver, mandible, pelvis, and teeth were determined by measuring inorganic phosphate that converts from fructose-1.6-diphosphate and using spectrophotometer at 350 nm. The differences in the acid-base status and FDPase activity in the groups 1 and 2 were statistically significant in comparison with the control and group 3 (P < 0.001). Increased FDPase activities are associated with acid-base status. The minerals and vitamins supplementation proved to restore acid-base balance, reduce toxicity and establish steady enzyme activity, which has not been previously reported.

[Evaluation of oral injuries in experimental induced diabetes mellitus by analysis of some gingival fluid markers]

AIM

The objective of this study was to determine the relationship between the activity of the enzyme aspartate aminotransferase (AST) and IL1-beta in gingival crevicular fluid (GCF) on animal model with experimentally induced diabetes mellitus and periodontal disease.

MATERIAL AND METHOD

During our study we used 15 Wistar rats, divided into three groups: I--control, II--with experimental model of periodontal disease, III--with experimental model of periodontal disease and diabetes. The sampling of GCF was realized using Whatman no. 1 paper strips introduced in the gingival sulci from mandibular left and right molars. For the determination of AST in GCF we used a spectrophotometric method while gingival fluid IL-1beta determinations were realized through immune enzymatic methods, using an ELISA kit (rlL-1beta).

RESULTS

The results displayed 3.47 times increased gingival fluid AST values in the stimulated experimental model (with periodontal alteration) when compared to control values (without periodontal disease), while in diabetes an increase of 6.139 times higher compared to control (without periodontal disease) were recorded. Moreover, the levels of periodontal disorder-induced IL-1beta were 3.54 times higher compared to control (group II--218.490 pg/mL vs group I--61.691 pg/mL), the most significant increase being recorded for the group with diabetes associated to periodontitis (492.129 pg/mL).

CONCLUSION

The present study found a high level of agreement between the presence of AST and IL-1beta in GCF in the experimental model of diabetes associated to periodontal disease, elevated when compared with the periodontal disease only model, and both higher when compared to control group.

A 52-kDa leucyl aminopeptidase from treponema denticola is a cysteinylglycinase that mediates the second step of glutathione metabolism

The metabolism of glutathione by the periodontal pathogen Treponema denticola produces hydrogen sulfide, which may play a role in the host tissue destruction seen in periodontitis. H2S production in this organism has been proposed to occur via a three enzyme pathway, gamma-glutamyltransferase, cysteinylglycinase (CGase), and cystalysin. In this study, we describe the purification and characterization of T. denticola CGase. Standard approaches were used to purify a 52-kDa CGase activity from T. denticola, and high pressure liquid chromatography electrospray ionization tandem mass spectrometry analysis of this molecule showed that it matches the amino acid sequence of a predicted 52-kDa protein in the T. denticola genome data base. A recombinant version of this protein was overexpressed in and purified from Escherichia coli and shown to catalyze the hydrolysis of cysteinylglycine (Cys-Gly) with the same kinetics as the native protein. Surprisingly, because sequence homology indicates that this protein is a member of a family of metalloproteases called M17 leucine aminopeptidases, the preferred substrate for the T. denticola protein is Cys-Gly (k cat/Km of 8.2 microm(-1) min(-1)) not l-Leu-p-NA (k cat/Km of 1.1 microm(-1) min(-1)). The activity of CGase for Cys-Gly is optimum at pH 7.3 and is enhanced by Mn2+, Co2+, or Mg2+ but not by Zn2+ or Ca2+. Importantly, in combination with the two other previously purified T. denticola enzymes, gamma-glutamyltransferase and cystalysin, CGase mediates the in vitro degradation of glutathione into the expected end products, including H2S. These results prove that T. denticola contains the entire three-step pathway to produce H2S from glutathione, which may be important for pathogenesis.

[Activity of salivary glutathione-dependent enzymes in patients with periodontitis]

Forty-five patients aged 20-47 years who had mild, moderate, or severe periodontitis and 32 healthy individuals (a control group) were studied during 10-15-day treatment with traditional therapy and combined therapy including the traditional approach and the antihomotoxic agent Traumeel S ointment as a supplement. Increased free radical generation and lipid peroxidation were considered to play an important role in the pathogenesis of periodontitis. Salivary indices are a reflection of a patient's metabolic state and have clinical diagnostic values in patients with oral tissue inflammation. The activities of antioxidative enzymes (glutathione reductase, glutathione-S-transferase, glucose-6-phosphate dehydrogenase) and the content of reduced glutathione (GSH) were determined in the saliva of patients with periodontitis during traditional and complex (traditional + Traumeel S) therapies. Inflammation led to metabolic disturbances and antioxidative defense system imbalance in patients with periodontitis. The findings suggest that the complex therapy with Traumeel S restored antioxidative defense balance and it was more effective than the traditional therapy in patients with periodontitis. An analysis showed a direct correlation between the activity of antioxidative enzymes and clinical characteristics of the disease. These results reflect the activity of a pathological process and the imbalance of antioxidative defense in patients with periodontitis.

Superoxide dismutase activity in gingiva in type-2 diabetes mellitus patients with chronic periodontitis

OBJECTIVE

Antioxidant defence reduces in diabetes mellitus (DM) and periodontitis. This study investigates antioxidant enzyme; superoxide dismutase (SOD) activity in gingiva and blood glucose and lipid levels in type-2 DM patients and systemically healthy individuals with chronic periodontitis (CP).

MATERIALS AND METHODS

Periodontal parameters, blood glycated-haemoglobin (HbA1c), glucose and lipid levels, and gingival-SOD activities (spectrophotometric assay) were measured in 17 DM patients with CP (DMCP), 17 systemically healthy CP patients, 18 periodontally healthy DM patients (DMPH), and 17 healthy controls (PH).

RESULTS

Periodontal parameters were higher in periodontitis groups than the controls (p<0.05), while there was no difference between the periodontitis groups and between the control groups. HbA1c, glucose, and triglyceride levels were higher in diabetic groups than the non-diabetic groups (p<0.05). Low-density lipoprotein (LDL), very-LDL and cholesterol values of the DMCP group did not significantly differ from the CP group. No differences existed between diabetic patients with and without periodontitis in HbA1c, glucose, and lipid levels and the same was true for non-diabetic patients with and without periodontitis. Gingival-SOD activity was lower in periodontitis groups than the matched control groups (p<0.05). DMPH group had the highest and CP group had the lowest SOD levels. There were correlations between periodontal parameters, gingival-SOD activity, HbA1c, glucose and high-density lipoprotein (HDL) levels.

CONCLUSION

The results suggest that gingival-SOD activity increases in diabetes and decreases in periodontitis and relations may exist between gingival-SOD activity, periodontal status, HbA1c, glucose and HDL levels. The higher gingival-SOD activity in diabetes may be attributed to an adaptive mechanism in the tissue.

[Microbiological and biochemical characteristics of inflammatory tissues in the periodontium]

OBJECTIVE

To investigate bacterial populations in subgingival and supragingival plaque samples of patients with inflammatory periodontal diseases and activities of the lysosomal enzymes--lysozyme, alkaline phosphatase, and beta-glucuronidase--in peripheral venous blood, in gingival crevicular fluid, and mixed nonstimulated saliva.

METHODS AND MATERIALS

The study included 60 patients with inflammatory periodontal diseases without any internal pathology and 24 periodontally healthy subjects. Molecular genetic assay (Micro-IDent plus, Germany) for complex identification of additional six periodontopathic bacteria was applied. The activity of lysozyme was determined turbidimetrically, the activity of alkaline phosphatase--spectrophotometrically with a "Monarch" biochemical analyzer, the activity beta-glucuronidase--according to the method described by Mead et al. and modified by Strachunskii.

RESULTS

A statistically significant association between clinical and bacteriological data was found in the following cases: gingival bleeding in the presence of Eubacterium nodatum, Eikenella corrodens, Capnocytophaga spp. (P<0.01); pathological periodontal pockets in the presence of Peptostreptococcus micros (alpha< or =0.05 and beta< or =0.2), Fusobacterium nucleatum (alpha< or =0.05 and beta< or =0.2), Campylobacter rectus (alpha< or =0.05 and beta< or =0.2), and Capnocytophaga spp. (P<0.05); and satisfactory oral hygiene in the presence of all microorganisms investigated (P<0.05). The activity of lysozyme in gingival crevicular fluid and mixed nonstimulated saliva indicates the severity of periodontal inflammation. Based on clinical data, in assessing the amount of lysozyme in mixed nonstimulated saliva, sensitivity and specificity of 100% was found. Increased activities of lysozyme, alkaline phosphatase, and beta-glucuronidase were found in peripheral venous blood of patients with inflammatory periodontal disease as compared to control group.

CONCLUSIONS

The main principles of the treatment of periodontal inflammatory diseases should be based on microorganism elimination, creation of individual treatment means affecting microflora in the mouth and immune system of macroorganisms.

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

BACKGROUND

The balance between the degradation and synthesis of extracellular matrix determines periodontal attachment levels and alveolar bone matrix concentration in periodontal diseases. Matrix metalloproteinases (MMPs) are known to degrade periodontal ligamental attachment and bone matrix proteins. The purpose of this study was to examine the effect of different expression levels of MMPs and their inhibitors, the tissue inhibitors of matrix metalloproteinases (TIMPs), in periodontitis.

METHODS

Sixteen inflamed gingival tissue samples from subjects with generalized chronic periodontitis and 14 control tissue samples from systemically and periodontally healthy subjects were evaluated. The total RNA was extracted, and the transcript levels for MMP-1, -3, -9, and -13 and TIMP-1, -2, -3, and -4 relative to beta-actin were determined by quantitative real-time reverse transcription-polymerase chain reaction.

RESULTS

Gene transcript levels for MMP-1 and TIMP-4 were significantly higher in periodontitis-affected gingival tissues (P <0.05). MMP-3, -9, and -13 and TIMP-1 mRNAs also were elevated in periodontitis; however, the difference was not statistically significant. TIMP-2 and -3 mRNA levels were similar in healthy and diseased gingivae. The ratios of MMP-1/TIMP-2 (P <0.01), MMP-3/TIMP-2 (P <0.05), MMP-9/TIMP-2 (P <0.05), and MMP-1/TIMP-3 (P <0.01) from periodontitis lesions were significantly higher than those in the control tissues.

CONCLUSIONS

Upregulated MMP expression and an increased MMP/TIMP ratio indicate that a potential imbalance between degradation and synthesis of extracellular matrix persists in periodontitis-affected gingival tissues. This process may be responsible for increased tissue breakdown in periodontitis.

Hyper-reactive PMNs in FcγRIIa 131 H/H genotype periodontitis patients

BACKGROUND

Receptors for the Fc part of IgG (FcgammaRIIa) on polymorphonuclear leukocytes (PMN) mediate phagocytosis and cell activation. Previous results show that one of the genetic variants of the FcgammaRIIa, the 131 H/H, is associated with more periodontal breakdown than the R/R. This may be due to hyper-reactivity of the H/H-PMNs upon interaction with bacteria.

AIM

To study whether the FcgammaRIIa genotype modifies the PMN reactivity in periodontitis patients.

MATERIAL AND METHODS

A cohort of 98 periodontitis patients was genotyped. From these, 10 H/H and 10 R/R consented to participate. PMNs were incubated with immune serum-opsonized Actinobacillus actinomycetemcomitans (A.a.). Phagocytosis, degranulation (CD63 and CD66b expression), respiratory burst and elastase release were assessed.

RESULTS

Patients of the H/H genotype showed more bone loss than those with the H/R or R/R genotype (p=0.038). H/H-PMNs phagocytosed more opsonized A.a. than did R/R-PMNs (p=0.019). The H/H-PMNs also expressed more CD63 and CD66b than did the R/R-PMNs (p=0.004 and 0.002, respectively) and released more elastase (p=0.001).

CONCLUSIONS

The genotyping results confirm previous reports that more periodontal destruction occurs in the H/H genotype than in the H/R or R/R genotype. The functional studies indicate a hyper-reactivity of the H/H-PMN in response to bacteria, which may be one of several pathways leading to more periodontal breakdown.

A hyperactive neutrophil phenotype in patients with refractory periodontitis

BACKGROUND

Neutrophils (PMNs) are critical components of the innate immune system and help to maintain oral health in the face of a constant bacterial challenge. However, along with protecting the periodontium from microbial invasion, these cells release potent lysosomal enzymes and oxygen radicals that can be destructive to periodontal tissues and lead to tooth loss. We examined neutrophil function in a unique population of patients diagnosed with refractory aggressive periodontitis (RAP).

METHODS

Venous blood was obtained from 12 non-smoking patients who had been diagnosed with RAP, 10 patients with chronic periodontitis who had responded to periodontal therapy (CP), and 13 periodontally healthy controls (HCs). Peripheral blood PMNs were loaded with dihydrorhodamine 123 and stimulated with phorbol 12-myristate 13-acetate (PMA) to measure the receptor-independent respiratory burst of these key immune cells. Phagocytosis via the complement and Fc-gamma receptors was also assessed.

RESULTS

PMNs from patients with RAP displayed significantly increased PMA-induced oxygen radical production compared to those from the HC and CP patients. PMNs from RAP patients also displayed increased phagocytosis compared to those from the CP group.

CONCLUSIONS

Our findings demonstrated a larger receptor-independent respiratory burst and higher phagocytotic activity in PMNs derived from patients with RAP compared to PMNs derived from CP patients and periodontally HCs. We speculate that the higher intrinsic intracellular activity of the nicotinamide adenine dinucleotide phosphate oxidase system may account for the continued periodontal breakdown, despite ongoing periodontal therapy in these challenging patients.

MMP-13 and TIMP-1 determinations in progressive chronic periodontitis

Matrix metalloproteinase (MMP)-13 is a collagenase involved in extracellular matrix degradation either by its direct degradative effects or by processing bioactive substrates. The aim of this study was to determine the levels of MMP-13 and tissue inhibitor of metalloproteinase (TIMP)-1 in gingival crevicular fluid (GCF) and gingival biopsies obtained from active and inactive sites during chronic periodontitis progression.

MATERIALS AND METHODS

This was a longitudinal study in which chronic periodontitis patients with moderate to severe disease were included and followed until they developed progression determined by the tolerance method. GCF samples were obtained from periodontitis, active, inactive and healthy sites and additional gingival biopsies were taken from active and inactive sites. MMP-13 and TIMP-1 determinations were carried out by immunodot blots and immunowestern blots.

RESULTS

In progressive periodontitis, MMP-13 and TIMP-1 remained unchanged between active and inactive sites, but as the TIMP-1 relative levels increased together with MMP-13 elevation in inactive samples, an inverse correlation was observed in active sites. Besides, MMP-13 was undetectable in healthy controls.

CONCLUSION

Chronic periodontitis is characterized by increased MMP-13 expression. During disease progression, active sites tended to decrease TIMP-1 levels in association with MMP-13 elevation.

p38 MAPK signaling in oral-related diseases

Multiple dental diseases are characterized by chronic inflammation, due to the production of cytokines, chemokines, and prostanoids by immune and non-immune cells. Membrane-bound receptors provide a link between the extracellular environment and the initiation of intracellular signaling events that activate common signaling components, including p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and nuclear factor (NF)-kappaB. Although ERK pathways regulate cell survival and are responsive to extracellular mitogens, p38 MAPK, JNK, and NF-kappaB are involved in environmental stress responses, including inflammatory stimuli. Over the past decade, significant advances have been made relative to our understanding of the fundamental intracellular signaling mechanisms that govern inflammatory cytokine expression. The p38 MAPK pathway has been shown to play a pivotal role in inflammatory cytokine and chemokine gene regulation at both the transcriptional and the post-transcriptional levels. In this review, we present evidence for the significance of p38 MAPK signaling in diverse dental diseases, including chronic pain, desquamative disorders, and periodontal diseases. Additional information is presented on the molecular mechanisms whereby p38 signaling controls post-transcriptional gene expression in inflammatory states.

Neutrophil elastase is involved in the initial destruction of human periodontal ligament

BACKGROUND AND OBJECTIVE

It has been reported that noncollagenous proteins may provide mechanical strength to the periodontal ligament. Several proteolytic activities, including that of neutrophil elastase, are reported to increase significantly in periodontal disease. The aim of this study was to investigate the function of neutrophil elastase in the initial destruction of periodontal ligament at early stages of periodontal disease.

MATERIAL AND METHODS

The detection and identification of proteinases in chronic periodontitis and healthy periodontal ligament were examined by zymographic and zymo-Western analysis. The morphological changes of periodontal ligament, digested with or without authentic proteinases, were observed using scanning electron microscopy.

RESULTS

Increases in neutrophil elastase, plasminogen, and matrix metalloproteinase-9 were detected in periodontal ligament from chronic periodontitis, compared with healthy periodontal ligament. Among these proteinases, only neutrophil elastase digested the intact noncollagenous proteins of periodontium. When human healthy periodontal ligament was directly digested by neutrophil elastase in an in vitro system, the morphological features were quite similar to that of the periodontal ligament in chronic periodontitis . In healthy periodontal ligament, the collagen fibrils are covered with noncollagenous proteins containing 110 kDa acidic glycoprotein, which was degraded initially by the neutrophil elastase.

CONCLUSION

It was concluded that neutrophil elastase is involved in the degradation of noncollagenous protein-covered collagen fibrils in the early destructive stages of periodontal disease.

Periodontal therapy reduces arginase activity in saliva of patients with chronic periodontitis

This present study evaluated the salivary arginase activity (SAA) in patients with chronic periodontitis and the effect of periodontal therapy on the activity of such enzyme. Thirty-six patients (mean age, 45.97 +/- 14.52), 18 chronic periodontitis subjects (test group), and 18 periodontally healthy individuals (control group) participated in the study. Clinical periodontal examinations included measurements of probing pocket depth (PD), clinical attachment level (CAL), plaque (PI), and gingival (GI) indexes. The test group received periodontal therapy according to individual needs. The saliva sample was collected from all study population at baseline (both groups) and 30 days after periodontal therapy (test group). SAA was determined by measuring the L: -ornithine formation from L-arginine and was expressed as mU/ml. The results showed that the mean values of SAA were statistically different between control and test groups. SAA was about 2.5 times higher in test than control groups. Thirty days after periodontal therapy, enzyme levels were 1.56 times lower than before periodontal therapy. We concluded that SAA is increased in chronic periodontitis subjects when compared to periodontally healthy individuals and that periodontal therapy significantly reduced SAA levels. It was suggested that in the near future, SAA may be used as a salivary marker of periodontal status.

Effects of scaling and root planing and sub-antimicrobial dose doxycycline on oral and systemic biomarkers of disease in patients with both chronic periodontitis and coronary artery disease

OBJECTIVES

This study evaluated the effects of scaling and root planing (SRP) +/- sub-antimicrobial dose doxycycline (SDD) on gingival crevicular fluid (GCF) levels of matrix metalloproteinase (MMP) -1, -8, -13 and on serum levels of high-sensitivity C-reactive protein (HsCRP) and lipid fractions in patients with both chronic periodontitis (CP) and coronary artery disease (CAD).

MATERIAL AND METHODS

Thirty-six patients were randomly distributed into two groups (Placebo or SDD; 6 weeks) and both received two regimens of SRP. At baseline and 6 weeks, GCF and blood were collected and clinical indices were recorded. MMPs, HsCRP and lipid fractions were assayed.

RESULTS

There were statistically significant improvements for all clinical parameters, GCF volumes, GCF MMPs and serum levels of HsCRP, apolipoprotein-A (APO-A), high-density lipoprotein (HDL) and lipoprotein-a between pre- and post-treatment in both groups. Between groups, there were statistically significant greater improvements in pocket depth (PD), gingival index (GI), APO-A and HDL, favouring the group receiving SDD adjunctive to SRP (p < 0.05).

CONCLUSION

Greater improvement was detected for PD and GI, and for serum levels of APO-A and HDL cholesterol when using SRP+SDD compared with SRP+placebo in this study. An investigation with larger numbers of patients and a longer duration of drug treatment is needed to confirm these preliminary findings.

Effect of systemically administered naproxen sodium on clinical parameters and myeloperoxidase and elastase-like activity levels in gingival crevicular fluid

BACKGROUND

The present study was conducted to determine the possible effect of naproxen sodium on clinical status and the enzymatic profile of gingival crevicular fluid (GCF) when given as adjunct to periodontal treatment.

METHODS

A total of 34 subjects with chronic periodontitis were selected and divided into two groups to receive either naproxen sodium or placebo. At baseline, GCF samples were obtained and probing depths (PD), gingival index (GI), plaque index (PI), and gingival bleeding index (GBI) scores were recorded. In the non-steroidal anti-inflammatory drug (NSAID) group, patients were treated with a protocol consisting of baseline periodontal treatment (scaling, root planing) and naproxen sodium (275 mg) administration daily for 6 weeks. In the placebo group, patients received the same treatment except placebo was given instead of naproxen sodium. At the end of the experimental period, clinical recordings and GCF sampling were repeated. Myeloperoxidase (MPO) and elastase-like enzyme activity (ELA) levels were determined in GCF samples by a spectrophotometric method. GCF enzymatic content was calculated both as total enzyme activity and enzyme concentration.

RESULTS

All of the clinical parameters, except mean GBI, were significantly lower in the experimental group (P <0.05). At baseline and at the end of the experimental period, there were no significant differences between the NSAID and placebo groups regarding GCF MPO and ELA levels in either mode of data presentation (P <0.05). However, in the NSAID group, mean ELA concentration (P = 0.002) and mean total ELA (P = 0.003) presented significant decreases with treatment. Also, with treatment, a general reduction in MPO levels was seen; however, this difference was not significant. Although constant and stable correlations between GCF enzyme levels and clinical parameters could not be found, positive and strong correlations were observed between total enzyme activity and enzyme concentrations.

CONCLUSION

Based on the positive clinical effect and the ELA profile of GCF, it can be suggested that NSAIDs given as an adjunct to baseline periodontal treatment could be beneficial in the outcome of treatment.

Lab-on-a-chip methods for point-of-care measurements of salivary biomarkers of periodontitis

Salivary secretions contain a variety of molecules that reflect important pathophysiological activities. Quantitative changes of specific salivary biomarkers could have significance in the diagnosis and management of both oral and systemic diseases. Modern point-of-care technologies with enhanced detection capabilities are needed to implement a significant advancement in salivary diagnostics. One such promising technology is the recently described lab-on-a-chip (LOC) assay system, in which assays are performed on chemically sensitized beads populated into etched silicon wafers with embedded fluid handling and optical detection capabilities. Using this LOC system, complex assays can be performed with small sample volumes, short analysis times, and markedly reduced reagent costs. This report describes the use of LOC methodologies to assess the levels of interleukin-1beta (IL-1beta), C-reactive protein (CRP), and matrix metalloproteinase-8 (MMP-8) in whole saliva, and the potential use of these biomarkers for diagnosing and categorizing the severity and extent of periodontitis. This study demonstrates that the results achieved by the LOC approach are in agreement with those acquired with standard enzyme-linked immunosorbent assay (ELISA), with significant IL-1beta and MMP-8 elevations in whole saliva of periodontitis patients. Furthermore, because of the superior detection capacities associated with the LOC approach, unlike those with ELISA, significant differences in CRP levels between periodontitis patients and normal subjects are observed. Finally, principal component analysis (PCA) is performed to yield an efficient method to discriminate between periodontally healthy and unhealthy patients, thus increasing the diagnostic value of these biomarkers for periodontitis when examined with the integrated LOC sensor system.

Rapid quantitative chairside test for active MMP-8 in gingival crevicular fluid: first clinical data

In a first pilot field study 64 gingival crevicular fluid (GCF) samples were collected from patients of dental practitioners. The dentists (one orthodontist one periodontist, and one general practitioner) were asked to monitor the respective clinical status of the sites of sampling and to collect, if possible, sulcus fluid samples from healthy as well as affected sites from the same patient. The concentration of activated matrix metalloproteinase-8 (aMMP-8) in the GCF was recorded using a set of monoclonal antibodies and a novel DentoAnalyzer. From all three dental offices the distribution of the aMMP-8 values in GCF showed a congruent pattern, where healthy and periodontitis-affected inflamed sites were clearly disparate.

MMP-2, MMP-9 and TIMP-2 gene polymorphisms in Chinese patients with generalized aggressive periodontitis

BACKGROUND

Aggressive periodontitis (AgP) has a genetic basis. It has been reported that the functional gene polymorphisms of matrix metalloproteinase (MMP)-2, MMP-9 and tissue inhibitor of metalloproteinase-2 (TIMP-2) alter their expressions in transcriptional level and they are involved in the tissue destruction of periodontitis. The study was carried out to analyse the association of functional polymorphisms in MMP-2, MMP-9 and TIMP-2 with generalized AgP (G-AgP) in a Chinese population.

MATERIAL AND METHODS

The study population consisted of 79 Chinese patients with G-AgP and 128 healthy controls. DNA was obtained from oral mucosa swab samples. MMP-2 genotypes were determined by PCR-based denaturing high-performance liquid chromatography analysis while MMP-9 and TIMP-2 genotypes were identified by a PCR-based restriction fragment length polymorphism. Chi2 test after Yates' correction was used to investigate the possible association of the genotypes with the G-AgP.

RESULTS

Although gene polymorphisms for MMP-2 and MMP-9 did not show any association with the G-AgP, the analysis of the TIMP-2 -418G to C gene polymorphism revealed significant differences between the patients and controls. Compared with controls, a significant increasing trend of TIMP-2 -418C carrier in the G-AgP patients occurred (p=0.013).

CONCLUSION

It is suggested that the TIMP2 -418G to C gene polymorphism is associated with G-AgP in the Chinese subjects.

Salivary enzyme levels after scaling and interleukin-1 genotypes in Japanese patients with chronic periodontitis

BACKGROUND

Saliva has been used as a diagnostic fluid in medicine and dentistry. It is easy to collect using non-invasive methods. The intracellular enzymes present in saliva have been studied as markers of periodontal disease. The purpose of this study was to determine the salivary enzyme levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) after scaling and to clarify the influence of interleukin (IL)-1 genotypes on these enzyme levels.

METHODS

Forty-nine Japanese patients with chronic periodontitis (24 men and 25 women; mean age: 55.1 years) were enrolled in this study. Measurements of clinical parameters including probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) and collections of stimulated whole mixed saliva were performed at baseline and 4 weeks after scaling. After evaluation of salivary AST, ALT, and LDH levels, DNA was extracted from various cells in whole saliva. IL-1A+4845 G/T genotype was determined by polymerase chain reaction amplification, followed by enzyme digestion and electrophoresis. Statistical analysis was performed by the Wilcoxon signed-rank and Mann-Whitney U tests. A significant difference was set at P <0.05.

RESULTS

Mean PD, CAL, and BOP values significantly decreased after scaling (mean +/- SE: 3.2 +/- 0.1 mm to 2.6 +/- 0.1 mm in PD; 3.9 +/- 0.2 mm to 3.3 +/- 0.2 mm in CAL; and 41% +/- 4% to 18% +/- 3% in BOP) (P <0.001). The values of AST, ALT, and LDH were 77.0 +/- 7.5, 43.9 +/- 5.5, and 753.4 +/- 96.5 (units per liter [U/l]) at baseline, and significantly decreased to 55.5 +/- 6.5, 30.0 +/- 5.5, and 394.7 +/- 34.0 (U/l) after scaling, respectively (P = 0.01, P = 0.006, and P <0.001). The carriage rate of the IL-1A+4845 allele 2 was 24.5%. No difference was noted in the decrease in PD, CAL, and BOP after scaling between the carriers (N = 12) and non-carriers (N = 37) of IL-1A+4845 allele 2. However, the IL-1A allele 2 non-carriers displayed a significant decrease in salivary AST and ALT levels (P <0.001), in contrast to the carriers who did not show any changes in the salivary levels of the enzymes after scaling.

CONCLUSIONS

These results documented that salivary AST, ALT, and LDH levels reflect inflammation and destruction of periodontal tissue, suggesting clinically useful markers following periodontal therapy. In addition, although IL-1A+4845 alleles may not influence clinical parameters, they may influence post-scaling values of salivary AST and ALT.