Oral fluid elastase as an indicator of periodontal health

Correlations between different protein species of oral rinse MMP-8 and patient-related factors

OBJECTIVES

The aim of this study is to examine correlations between different oral rinse matrix metalloproteinase (MMP)-8 protein species in western blot (WB) analysis, quantitative MMP-8 measurements, and patient-related factors. Elevated activated MMP-8 (aMMP-8) associate with periodontitis and a diagnostic point-of-care technology has been developed based on aMMP-8. In WB, different MMP-8 protein species can be analyzed. Relative abundancy of fragmented 20-25 kDa forms in WB has been associated with and reflects MMP-8 activation and related fragmentation and elevated quantitative aMMP-8 measurements.

MATERIAL AND METHODS

A random sample of 192 participants from a periodontal disease screening study was used for this study. Oral rinse samples for biomarker analyses were collected before clinical periodontal examinations. aMMP-8 immunofluorometric (IFMA) and WB analysis (utilizing the same monoclonal antibody, 8708), polymorphonuclear leukocyte (PMN) elastase activity test and tissue inhibitor of metalloproteinases (TIMP)-1 ELISA levels were performed from the oral rinse samples. Distinct MMP-8 protein species were differentiated in the WB analysis. Principal component (PC) analysis was conducted to explore correlation patterns between the different species. Adjusted correlation analysis between the extracted PCs of WB and aMMP-8 IFMA levels and multilevel regression analysis were conducted to explore if the other periodontal disease-related biomarkers and clinical surrogate measures and patient-related factors are co-variating with the extracted components.

RESULTS

Distinct correlation patterns between the MMP-8 protein species were observed. The first four PCs explained 89% of the whole variance in PC analysis. Statistically significant correlation (p < 0.05) were observed as follows: PC1 positively with 21 kDa (r = .69) and 25 kDa fragments (r = .55) and negatively with 150 kDa complexes (r = -.46). PC2 correlated with 45 (r = .70) and 55 kDa (r = .65) activated forms, PC3 with 70-80 kDa latent proforms (r = .63) and 90-100 kDa complexes (r = .67), and PC4 with 35 kDa fragments (r = .81). There were significant correlations between quantitative (IFMA) aMMP-8 measurements and PC1 (p < 0.001), PC2 (<0.05) and PC3 (<0.05) but not with PC4. In multilevel regression models age, PMN elastase activity, TIMP-1 levels, and a number of 4-5 mm periodontal pockets were associated with PC1, nonsmoking with PC2, age and PMN elastase activity with PC3, and age and smoking with PC4.

CONCLUSIONS

Relative abundancy of fragmented 21-25 kDa protein species was correlated with the quantitative aMMP-8 (IFMA) measurements, which is in line with previous results. Different patient-related factors (smoking, age, proteolytic activity) may modify the formation of different MMP-8 protein species in oral rinse samples and may cause variability in quantitative aMMP-8 measurement.

Discovery, validation, and diagnostic ability of multiple protein-based biomarkers in saliva and gingival crevicular fluid to distinguish between health and periodontal diseases

Aim

To discover and validate differential protein biomarker expression in saliva and gingival crevicular fluid (GCF) to discriminate objectively between periodontal health and plaque‐induced periodontal disease states.

Materials and Methods

One‐hundred and ninety participants were recruited from two centres (Birmingham and Newcastle upon Tyne, UK) comprising healthy, gingivitis, periodontitis, and edentulous donors. Samples from the Birmingham cohort were analysed by quantitative mass spectrometry proteomics for biomarker discovery. Shortlisted candidate proteins were then verified by enzyme‐linked immunosorbent assay in both cohorts. Leave‐one‐out cross validation logistic regression analysis was used to identify the best performing biomarker panels.

Results

Ninety‐five proteins were identified in both GCF and saliva samples, and 15 candidate proteins were selected based upon differences discovered between the donor groups. The best performing panels to distinguish between: health or gingivitis and periodontitis contained matrix metalloproteinase‐9 (MMP9), S100A8, alpha‐1‐acid glycoprotein (A1AGP), pyruvate kinase, and age (area under the curve [AUC] 0.970); health and gingivitis contained MMP9, S100A8, A1AGP, and pyruvate kinase, but not age (AUC 0.768); and mild to moderate and advanced periodontitis contained MMP9, S100A8, A1AGP, pyruvate kinase, and age (AUC 0.789).

Conclusions

Biomarker panels containing four proteins with and without age as a further parameter can distinguish between periodontal health and disease states.

Resistance and resilience to experimental gingivitis: a systematic scoping review

Background

This systematic scoping review aimed to identify changes in biomarkers of microbiological, immunological and biochemical origin during experimental gingivitis (EG) studies that might indicate resistance and resilience.

Methods

The term ‘experimental gingivitis’ was run in PubMed from inception to April 11th, 2018. From the 411 studies retrieved, 22 studies were included for this review.

Results

Studies reporting data on biomarker changes during and after full mouth EG trial were included. Two studies reported findings on changes in biomarkers of microbiological, 12 on immunological and eight on biochemical origin. Changes were reported in the induction phase, and occasionally in the resolution phase. The microbiological composition of both supragingival and subgingival dental plaque changed over the course of EG to a more pathogenic direction, but showed a shift back to a more normal composition. This indicates resilience of the oral microbiome. For immunological biomarkers, it was challenging to retrieve a robust pattern of changes across multiple studies. IL-1β and IL-6 in saliva and in gingival crevicular fluid increased during induction phase and returned in the resolution phase below baseline values. The biochemical parameters cystatin-SN, cystatin-S and lactoferrin in saliva were increased at the end of induction phase, however also here no clear pattern emerged based on all available studies.

Conclusions

More research is needed to investigate which microbiological, immunological, and biochemical biomarkers can be useful for future investigations into the resistance and resilience of the oral cavity to experimental gingivitis.

Electronic supplementary material

The online version of this article (10.1186/s12903-019-0889-z) contains supplementary material, which is available to authorized users.

Salivary levels of MPO, MMP-8 and TIMP-1 are associated with gingival inflammation response patterns during experimental gingivitis

AIM

This study aimed to investigate the association between salivary levels of myeloperoxidase (MPO), neutrophil elastase (NE), soluble urokinase-type plasminogen activator receptor (suPAR), matrix metalloproteinase (MMP)-8 and tissue inhibitor of matrix metalloproteinases (TIMP)-1 and gingival inflammation development during an experimental gingivitis study.

METHODS

A three-week experimental gingivitis study was conducted. Clinical recordings of dental plaque biofilm (Modified Quigley Hein Plaque Index, TQHPI) and gingival inflammation (Modified Gingival Index, MGI) were made at specific time points for each of the 42 participants. Salivary levels of MPO, NE, suPAR, MMP-8 and TIMP-1 at the same time points were measured using distinct immunoassays. For data analysis growth curve modelling was employed to account for the time-varying outcome (MGI score) and the time-varying covariates (salivary marker levels, and TQHPI score). Analyses were stratified according to the MGI-score trajectory groups previously identified as 'fast', respectively 'slow' responders.

RESULTS

Overall, higher MGI scores were statistically significantly positively associated with higher levels of MPO, MMP-8 and TIMP-1. Stratified analysis according to inflammation development trajectory group revealed higher levels of salivary MPO, MMP-8 and MMP-8/TIMP-1 ratio among the 'fast' responders than among 'slow' responders. None of the investigated salivary protein markers was associated with a 'slow' inflammation development response.

CONCLUSIONS

Salivary levels of MPO, MMP-8 and TIMP-1 were associated with the extent and severity of gingival inflammation. While the 'fast' gingival inflammation response was associated with increased levels of MPO, MMP-8 and MMP-8/TIMP-1 ratio, the 'slow' response was not associated with any of the salivary protein markers investigated in this study. Neutrophil activity seems to orchestrate a 'fast' gingival inflammatory response among participants previously primed to gingival inflammation.

Salivary proteolytic activities in periodontitis, gingivitis and diabetes mellitus

Elastase activity was found to be significantly increased in periodontitis (0.872±0.4270 absorbance units/mg protein, mean±S. D., 1.05±0.61 units/ml saliva), gingivitis (0.772±0.416 units/mg protein, 1.515±0.952 units/ml) and diabetes (0.549±0.286 units/mg protein, 1.20±0.769 units/ml) compared to normals (0.255±0.089) units/mg protein, 0.264±0.079 units/ml). Chymotryptic activity was not found to be increased in these disease conditions over the normal level (0.284±0.096 units/mg protein). Aminopeptidase activity was elevated only in periodontitis (0.670+0.140 units/mg protein) compared to normals (0.349±0.100 units/mg protein). Trypsin-like activity was also found to be significantly raised in periodontitis compared to normals when Pro-Phe-Arg-p-nitroanilide (0.666±0.204 units/mg protein), Ile-Pro-Arg-p-nitroanilide (1.59±0.260 units/mg protein) and Pyroglu-Pro-Arg-p-nitroanilide (1.82±0.380 units/mg protein) were used as substrates. The normal values with these three substrates were respectively, 0.454±0.110, 1.04±0.231 and 1.15±0.312 units/mg protein. Total protein level in saliva was found to be significantly elevated in gingivitis (209±66.8 mg/dl) and diabetes (204±68.0) compared to normal values (107±20.7). Increase in periodontitis was marginal (127±28.3 mg/dl). Expression of proteolytic activities normalized to protein level was useful in differential diagnosis. Increase in elastase level in saliva is not a specific marker for periodontal diseases.

Role of salivary leukocyte protease inhibitor in periodontal disease progression

CONTEXT

Proteases play a major role in the tissue destruction involved in periodontal disease. It is known that the balance between proteases and their inhibitors is a major determinant in maintaining tissue integrity. The association between the proteases and periodontitis is well established, but not many studies have been carried out to know the role played by a protease inhibitor like salivary leukocyte protease inhibitor (SLPI) in periodontitis.

AIM

The aim of the present study was to correlate SLPI with periodontitis.

SETTINGS AND DESIGN

Case-control study.

MATERIALS AND METHODS

Seventy-five clinically confirmed cases of periodontitis and 20 controls were included in the study. A detailed case history and periodontal index (PI) were recorded. Two milliliters of unstimulated saliva samples was obtained and subjected to quantification of SLPI leaves using SLPI in enzyme-linked immunosorbent assay (ELISA) kit. Based on the periodontal index score of the individuals, the cases and controls were divided into groups A, B and C, and the obtained SLPI levels were compared among the groups.

STATISTICAL ANALYSIS

Mann-Whitney U test and correlation coefficient test.

RESULTS

The results showed that in the initial stages of periodontitis there is a tendency of SLPI levels to be raised. The SLPI levels were found to be reduced in the terminal stages of periodontitis.

CONCLUSION

It appears that SLPI accumulates in the local environment, at least in the initial stages of the periodontal disease, probably to inhibit the action of increased elastic activity.

Longitudinal study of salivary proteinases during pregnancy and postpartum

BACKGROUND AND OBJECTIVE

Matrix metalloproteinases (MMPs) and their regulators are connected to periodontal inflammation and destruction. However, the presence and role of the salivary MMPs in pregnancy-related gingivitis are not well known. Our longitudinal study aimed to monitor salivary proteinase levels and possible changes, and relate them to periodontal status during pregnancy and postpartum.

MATERIAL AND METHODS

Salivary samples were collected from 30 periodontally healthy pregnant women five times (once during each trimester, 4-6 wk after delivery and after lactation) and, as their controls, from 24 non-pregnant women three times (during successive months). Periodontal examination included visible plaque index, bleeding on probing, probing pocket depth and clinical attachment level measurements. Matrix metalloproteinase-8 levels were measured by immunofluorometric assay, and MMP-2 and MMP-9 levels and molecular forms by gelatin zymography. Salivary elastase, myeloperoxidase and tissue inhibitor of matrix metalloproteinase-1 levels were measured by ELISA.

RESULTS

Elastase concentrations maintained stable during the follow-up, while myeloperoxidase concentrations increased significantly after delivery. During pregnancy, MMP-8 concentrations were significantly lower than postpartum concentrations, being lowest during the second trimester and highest after delivery, and varying inversely to pregnancy gingivitis, observed as elevated percentages of bleeding on probing and probing pocket depth during the second and third trimester. In pregnant women, the highest MMP-2 and MMP-9 levels were found in saliva after lactation. In the control group, both clinical and enzymological findings remained stable during the follow-up period.

CONCLUSION

Our results suggest that hormonal changes during pregnancy induce or enhance susceptibility to gingivitis, while salivary proteinase and myeloperoxidase levels are reduced.

Current developments in salivary diagnostics

Salivary diagnostics is an emerging field that has progressed through several important developments in the past decade, including the publication of the human salivary proteome and the infusion of federal funds to integrate nanotechnologies and microfluidic engineering concepts into developing compact point-of-care devices for rapid analysis of this secretion. In this article, we discuss some of these developments and their relevance to the prognosis, diagnosis and management of periodontitis, as an oral target, and cardiovascular disease, as a systemic example for the potential of these biodiagnostics. Our findings suggest that several biomarkers are associated with distinct biological stages of these diseases and demonstrate promise as practical biomarkers in identifying and managing periodontal disease, and acute myocardial infarction. The majority of these studies have progressed through biomarker discovery, with the identified molecules requiring more robust clinical studies to enable substantive validation for disease diagnosis. It is predicted that with continued advances in this field the use of a combination of biomarkers in multiplex panels is likely to yield accurate screening tools for these diagnoses in the near future.

Degradation of noncollagenous components by neutrophil elastase reduces the mechanical strength of rat periodontal ligament

BACKGROUND AND OBJECTIVE

We have previously shown that increases in neutrophil elastase in periodontal ligament with chronic periodontitis results in degradation of the noncollagenous components. The purpose of this study was to investigate whether the destruction of noncollagenous components by treatment with elastase in vitro causes changes in the mechanical properties of the periodontal ligament.

MATERIAL AND METHODS

The transverse sections of mandibular first molars, prepared from male Wistar rats at 6 wk of age, were digested with 0-50 microg/mL of neutrophil elastase at 37 degrees C for 4 h. Then, their mechanical properties and morphological features were examined.

RESULTS

Digestion with elastase dose-dependently decreased the maximum shear stress and failure strain energy density of the periodontal ligament (p < 0.05-0.01). The histological observations after digestion revealed marked degradation of oxytalan fibers, but no marked changes of the collagen fibers, which was confirmed by the detection of very low quantities of hydroxyproline in the digest. The light and scanning electron micrographs showed that the elastase degraded the interfibrillar substances in the periodontal ligament and exposed individual collagen fibrils.

CONCLUSION

These results suggest that the increased neutrophil elastase observed in periodontal disease degrades the oxytalan fibers and interfibrillar substances in the periodontal ligament to decrease its mechanical strength.

Secretory leukocyte protease inhibitor and its potential interactions with elastase and cathepsin B in gingival crevicular fluid and saliva from patients with chronic periodontitis

BACKGROUND AND OBJECTIVE

Elastase is carried into the oral cavity by gingival crevicular fluid (GCF) from periodontal lesions. Our study investigated the regulation of elastase activity by secretory leukocyte protease inhibitor (SLPI) and the possible action of another GCF protease on this protective salivary component.

MATERIAL AND METHODS

Whole-mouth saliva (WMS), parotid saliva (PS) and GCF were obtained from 19 patients with periodontitis. The concentrations of active elastase and cathepsin B were determined using peptide substrates. SLPI and alpha1-proteinase inhibitor (alpha1PI) concentrations were determined using enzyme-linked immunosorbent assays (ELISAs). The molecular forms of SLPI were examined by immunoblotting.

RESULTS

The molar concentrations of elastase, cathepsin B and alpha1PI were higher in GCF than in WMS and especially PS (p < 0.0002). The GCF SLPI concentrations were also higher than the WMS SLPI concentrations (p < 0.05). All WMS components increased with GCF content, significantly for elastase and SLPI (p < 0.002). In GCF, the concentration of alpha1PI was higher than the concentration of SLPI (p < 0.0002), while there was no significant difference for WMS. SLPI and elastase levels in GCF and WMS were inversely related (p < 0.005). In SLPI immunoblots, PS contained only the intact 14-kDa molecule of SLPI, while WMS also contained an 8-kDa fragment. For WMS there was a positive correlation between SLPI degradation and cathepsin B (p < 0.002). Incubation of WMS alone or of PS with GCF in the presence of cysteine proteinase activators caused SLPI immunoreactivity to shift to 8 kDa.

CONCLUSION

For GCF, serum-derived alpha1PI is the major elastase inhibitor, but in WMS SLPI probably reduces activity. The inflamed gingivae can be an additional source of SLPI in the oral cavity, but here the molecule is apparently cleaved by GCF cysteine proteinases, such as cathepsin B.

Cleaved inflammatory lactoferrin peptides in parotid saliva of periodontitis patients

Lactoferrin (Lf) is a member of the transferrin family of iron-binding anti-bacterial proteins, present in most exocrine secretions, such as saliva, and plays an important role in mucosal defense. In this study, we identified small Lf peptides with Con A low-affinity in the parotid saliva of chronic periodontitis patients by Con A two-dimensional immunoelectrophoresis, Con A affinity chromatography and Western blotting using anti-human Lf polyclonal Ab. N-terminal amino acid sequencing of the four Con A low-affinity Lf peptides confirmed them to be fragments of intact Lf. The detection ratio of the proteinase 3 (PR3)-like activity was elevated in the parotid saliva of periodontitis patients and was associated with the severity of clinical symptoms. PR3 protein was also detected in the parotid saliva of periodontitis patients, and PR3, but not human leukocyte elastase and cathepsin G, degraded intact Lf. Con A low-affinity saliva Lf peptides showed no anti-bacterial activity against Escherichia coli, and had a reduced iron-chelating capacity. Con A low-affinity saliva Lf peptides, PR3-treated Lf preparation and two of four synthetic polypeptides induced the production of interleukin IL-6, monocyte chemoattractant protein-1 and IL-8, and the activation of NF-kappaB in human oral epithelial HSC-2 cells. Furthermore, concentrations of the Lf peptides in the parotid saliva of periodontitis patients were increased with a correlation to the severity of clinical symptoms. These results suggest that Lf in the parotid saliva of periodontitis patients was degraded into small peptides by the PR3-like activity with the capability to induce inflammatory mediators.

Relationship between periodontal disease status and combination of biochemical assays of gingival crevicular fluid

BACKGROUND

Currently, no biochemical assay involving gingival crevicular fluid is utilized routinely as a screening test for periodontal disease.

OBJECTIVE

The objective of the present study was to evaluate the potential of gingival crevicular fluid assay as a screening methodology.

METHODS

The subject population was comprised of 27 volunteers. Nine participants were classified as 'subject with periodontal destruction' (SPD) exhibiting at least one site with pocket depth and attachment loss>3.5 mm, whereas the remaining individuals were categorized as 'subject with minimal periodontal destruction' (SMD). Gingival crevicular fluid was collected from fixed sites via a standardized method. Biochemical assays of 12 substances (hemoglobin, albumin, transferrin, alpha(1)-antitrypsin, fibronectin, IgA, IgG, IgM, lactoferrin, myeloperoxidase and neutrophil elastase) were conducted at a commercial laboratory. Power transformation of total quantities in gingival crevicular fluid was performed for statistical analysis.

RESULTS

Relationships between total quantity of each substance and periodontal disease status were unclear. Logistic regression analysis yielded six predictive models, which consisted of substance pairs: neutrophil elastase/IgA, neutrophil elastase/hemoglobin, neutrophil elastase/alpha(1)-antitrypsin and neutrophil elastase/IgG, and IgA/albumin and IgA/transferrin (p<0.05). Regression lines for SPD and SMD on a scattergram of IgA and neutrophil elastase were nearly parallel within the range of amounts in gingival crevicular fluid. The predictive model derived from both substances afforded sensitivity and specificity of 88% and 94%, respectively.

CONCLUSIONS

These results indicated that the combination of IgA and neutrophil elastase in gingival crevicular fluid may be crucial for prediction of periodontal disease status. Furthermore, these data suggested that biochemical assays employing both substances in gingival crevicular fluid may provide a satisfactory screening test for periodontal disease.

Use of saliva as a diagnostic fluid in dentistry

Saliva is a secretion of the salivary and mucous glands and is of major importance in the maintainance of oral health. Over the last few decades, saliva has been evaluated as a diagnostic fluid in medicine for determining systemic disease markers as well as for monitoring numerous drugs, narcotics, and hormones. The biochemical analysis of saliva is particularly important in dentistry. The estimation of the risk of appearance and diagnosis of disease, monitoring of disease progression, evaluation of therapy efficacy for caries, periodontitis, premalignant and malignant oral lesions, as well as infectious diseases of the oral cavity, can be assessed by analyzing different constituent: of saliva, individuals at risk of caries can be identified using test: that determine saliva flow rate, saliva buffer capacity, and colonization of the oral cavity by cariogenic bacteria. Today, these rapid and simple diagnostic tests are used routinely in caries risk determination. The study and use of saliva-based diagnostics have increased over the last few decades. Clinical testing of saliva shows much promise. However, there is a need for much additional research in this area, before the true clinical value of saliva as a diagnostic fluid in dentistry can be determined.

Position Paper: Diagnosis of Periodontal Diseases

At the present time, the diagnosis and classification of periodontal diseases are almost entirely based on traditional clinical assessments. Supplemental quantitative and qualitative assessments of the gingival crevicular fluid and subgingival microflora can potentially provide useful information about the patient's periodontal disease. In certain situations, these supplemental risk-assessment tests may be particularly valuable in establishing the endpoint of therapy prior to placing patients on a periodontal maintenance program. Although the clinical utility of none of these tests has been validated, their further development is warranted. A genetic test for susceptibility to periodontitis has become commercially available. How best to use this and future host-based tests in clinical practice remains to be determined. Probing depth and clinical attachment loss measurements obtained with periodontal probes are practical and valid methods for assessing periodontal status. Computer-linked, controlled-force electronic periodontal probes are commercially available and are currently in use by some practitioners. Many of the logistical problems associated with subtraction radiography are being overcome and this powerful diagnostic tool may soon come into widespread use. Future developments in this and other imaging techniques are likely to have a profound effect on our approach to the diagnosis of periodontal diseases.

Salivary non-immunoglobulin agglutinin inhibits human leukocyte elastase digestion of acidic proline-rich salivary proteins

Saliva contains acidic proline-rich salivary proteins that are involved in the formation of the salivary pellicle coating supragingival tooth surfaces. However, human leukocyte elastase, arriving in gingival exudates from inflamed periodontal tissues, degrades the acidic proline-rich salivary proteins, preventing binding to hydroxylapatite surfaces. Here it is reported that high-molecular-weight non-immunoglobulin salivary agglutinin inhibited the proteolytic action of human leukocyte elastase on purified acidic proline-rich salivary proteins. Inhibition was eliminated with monoclonal antibody to a protein determinant on the salivary agglutinin. The addition of antibody against salivary agglutinin blocked the inhibitory effect of parotid saliva on exogenously applied human leukocyte elastase, allowing for the elastase-mediated digestion of the salivary acidic proline-rich salivary proteins. Salivary agglutinin, therefore, is a physiologically important inhibitor of human leukocyte elastase and is able to inhibit elastase-mediated digestion of salivary acidic proline-rich proteins.

Effect of cigarette smoking on oral elastase activity in adult periodontitis patients

BACKGROUND

We have previously reported that elastase activity in oral fluids is significantly increased in most adult periodontitis patients. In some patients, however, elastase levels remain low despite the presence of deep periodontal pockets. In this study we explored whether or not smoking is related to the unexpected low elastase values in these patients.

METHODS

We determined what proportion of the periodontitis patients that showed low oral elastase values were smokers. Paraffin-stimulated saliva or oral rinse samples (3 ml of water, 30 second rinse) were assayed for elastase activity by incubating with 1 mM succinyl-alanyl-alanyl-valine-p-nitroanilide for 20 hours at 37 degrees C, and the color formation read with a spectrophotometer. Neutrophil numbers were analyzed by staining the cells in the oral rinse smear samples.

RESULTS

In 2 patient groups, one in Helsinki, Finland (n = 46) and the other in Vancouver, British Columbia (n = 25), 63% and 83%, respectively, of the adult periodontitis patients who had one or more pockets > or =6 mm and had low oral elastase values (increase of optical density <0.5) were smokers. Non-smoking periodontitis patients had elevated neutrophil numbers compared to healthy subjects, while the smoking patients showed no significant change. Next we analyzed elastase levels in stimulated whole saliva in a group of smokers (n = 300) and those who had quit smoking (n = 102). Smokers had significantly lower oral elastase levels than former smokers in both advanced and moderate periodontitis groups. In this subject group, 56% of all smokers with periodontitis (at least one pocket > or =6 mm) had oral elastase values less than 0.5 U while only 31% of those patients who had quit smoking had low values.

CONCLUSIONS

Cigarette smoking leads to lowered elastase and neutrophil levels in the oral cavity. The oral neutrophil elastase assay, therefore, cannot be used to measure the periodontal status of smokers.

The association between smoking cessation and periodontal status and salivary proteinase levels

BACKGROUND

Little information is available about the effects of the cessation of cigarette smoking on oral health, although cigarette smoking has been shown to be associated with a variety of oral diseases. The aim of this study was to compare periodontal status, salivary proteolytic activity, especially collagenase-2 (MMP-8) levels, and oral mucosal status in individuals who had quit smoking for at least 6 months (mean 3.5, SD 1.3 years) and in regular smokers.

METHODS

The subjects were 409 white male smokers aged 55 to 74 years with 15 or more remaining teeth. They had participated in a major cancer prevention study (ATBC Study). Eighty-two of the men had given up smoking and 327 were smokers. The subjects were examined clinically to determine the prevalence of periodontal pockets, gingival bleeding (BOP) and suppuration, and prevalence of keratotic oral mucosal lesions. The loss of alveolar bone was determined radiographically. Candida albicans was cultivated, and lesions showing leukoplakia were examined histopathologically. General proteolytic activity and collagenase-2 or matrix metalloproteinase-8 (MMP-8) levels in saliva, salivary pH, and buffering capacity were measured. Linear regression, logistic regression, or Fisher's exact test were used in statistical analysis.

RESULTS

Salivary general proteolytic activity and MMP-8 levels were lower in current smokers than in ex-smokers (P <0.05 and P <0.05, respectively). The prevalence of > or = 4 mm deep pockets, gingival suppuration, and loss of crestal bone were statistically significantly lower (P = 0.003, P<0.001, and P<0.05, respectively) and salivary buffering capacity higher (P <0.05) in those who had quit smoking compared to current smokers; there was no difference in BOP. The prevalence of oral leukoplakia did not differ significantly between smokers and quitters, but was higher in those who smoked >15 cigarettes per day compared to quitters (odds ratio 3.5, 95% CI, 0.8 to 15.3).

CONCLUSIONS

These data suggest that periodontal status and oral mucosal health are better in those who have quit cigarette smoking compared to current smokers. However, the data further suggest that smoking may significantly lower both general proteolytic enzyme activity and MMP-8 levels in saliva. Thus, care should be taken in interpreting results revealing salivary/mouthrinse proteinases as diagnostic markers for oral/periodontal disease activity.

Effects of removing the negatively charged N-terminal region of the salivary acidic proline-rich proteins by human leucocyte elastase

Human leucocyte elastase from inflammatory gingival crevicular exudates (gingival crevicular fluid) contacts saliva and saliva-coated tooth surfaces coronal to the gingival margin. Major components of saliva are the salivary acidic proline-rich proteins (PRPs). These acidic PRPs, via the numerous negatively charged amino acid residues located predominantly within their amino-terminal region, bind to the hydroxyapatite mineral of the tooth surface and become part of the salivary pellicle. Thus the potential for human leucocyte elastase-mediated removal of the negatively charged amino-terminal region of acidic PRP variants (PRP-1, PRP-2, PRP-3, PRP-4, PIF-s and PIF-f) was examined. It was determined that each of the acidic PRP variants was susceptible to fragmentation by human leucocyte elastase, in which the 16 amino-terminal segment was removed, leaving the respective residual fragment named as the transitional product (tr). The transitional products were termed PRP-1tr, PRP-2tr (PIF-str), PRP-3tr and PRP-4tr (PIF-ftr). Each of the residual transitional products of acidic PRP had an amino-terminal beginning with serine residue no. 17, determined by amino acid sequencing. When samples of human leucocyte elastase-treated acidic PRPs were placed on native polyacrylamide gels and electrophoresed, the respective transitional products moved more slowly than the parental acidic PRP molecules, reflecting the loss of a portion of the negatively charged section. In comparison to the acidic PRPs, the acidic PRP transitional products had markedly reduced binding to hydroxyapatite. The transitional products were resistant to further enzymatic digestion as a function of increased incubation time and appeared to exert an antihuman leucocyte elastase effect. However, when increased concentrations of human leucocyte elastase were incubated with the acidic PRP, a more extensive digestion occurred, leaving a residual peptide with an amino-terminal beginning with alanine residue no. 44. Interestingly, intact acidic PRPs if prebound to hydroxyapatite particles, resisted digestion by human leucocyte elastase. In summary, human leucocyte elastase was capable of digesting fluid-phase (unbound) acidic PRP in a manner that eliminated part of their negatively charged region, which subsequently reduced their binding to hydroxyapatite. High concentrations of human leucocyte elastase, arriving from inflammatory gingival crevicular exudates, may interrupt the normal binding of fluid-phase acidic PRPs to hydroxyapatite.

Purification and characterization of a novel cysteine proteinase (periodontain) from Porphyromonas gingivalis. Evidence for a role in the inactivation of human alpha1-proteinase inhibitor

Periodontal disease is characterized by inflammation of the periodontium manifested by recruitment of neutrophils, which can degranulate, releasing powerful proteinases responsible for destruction of connective tissues, and eventual loss of tooth attachment. Although the presence of host proteinase inhibitors (serpins) should minimize tissue damage by endogenous proteinases, this is not seen clinically, and it has been speculated that proteolytic inactivation of serpins may contribute to progression of the disease. A major pathogen associated with periodontal disease is the Gram-negative anaerobe Porphyromonas gingivalis, and in this report, we describe a novel proteinase that has been isolated from culture supernatants of this organism that is capable of inactivating the human serpin, alpha1-proteinase inhibitor, the primary endogenous regulator of human neutrophil elastase. This new enzyme, referred to as periodontain, belongs to the cysteine proteinase family based on inhibition studies and exists as a 75-kDa heterodimer. Furthermore, periodontain shares significant homology to streptopain, a proteinase from Streptococcus pyogenes, and prtT, a putative proteinase from P. gingivalis. Clearly, the presence of this enzyme, which rapidly inactivates alpha1-proteinase inhibitor, could result in elevated levels of human neutrophil elastase clinically detected in periodontal disease and should be considered as a potential virulence factor for P. gingivalis.

Expression of heparan sulphate and small dermatan/chondroitin sulphate proteoglycans in chronically inflamed human periodontium

Proteoglycans (PGs) function in regulating aspects of cell behavior, such as proliferation, adhesion, and migration. In this report, we investigated the localization of three heparan sulphate PGs (basement membrane [BM] heparan sulphate PG, CD44, and syndecan-1) and two small dermatan/chondroitin sulphate PGs (decorin and biglycan) in chronically inflamed human periodontium. Frozen sections were analyzed by immunofluorescence microscopy. In inflamed tissue, BM heparan sulphate PG showed reduced immunostaining in subepithelial and subendothelial basement membrane. Loss of CD44 and syndecan-1 was common in epithelial cells of inflamed periodontal tissue. Suprabasal keratinocytes of epithelium expressed involucrin, a cornified envelope protein and marker for epithelial differentiation, while the expression of syndecan-1 was weak or absent. In contrast, expression of the mesenchymal variant of CD44 and syndecan-1 was strong in infiltrating lymphocytes. Small dermatan/chondroitin sulphate PGs, decorin and biglycan, were also present in markedly reduced amounts in the periodontal connective tissue in chronic inflammation. In addition, decorin localized in the connective tissue along short rod-like structures. The results suggest that proteoglycan-dependent intercellular adhesion of keratinocytes is decreased and that adhesion of lymphocytes to matrix molecules via cell surface PGs increased in chronic inflammation. Disappearance of adhesion-modulating small dermatan/chondroitin sulphate PGs may further regulate cell migration in inflamed periodontium.

Early-onset periodontitis associated with Weary-Kindler syndrome: a case report

Weary-Kindler syndrome is a rare and poorly understood genetic disorder that has manifestations of both epidermolysis bullosa and poikiloderma congenitale. There are approximately 70 cases documented in the past 40 years but no cases appear in the dental literature, although dental findings have been discussed superficially in dermatological and pediatric publications. This case reports on the periodontal findings and treatment for a 16-year-old female diagnosed with the syndrome. Early exfoliation of deciduous teeth, severe periodontal bone loss around many permanent teeth, and fragile bleeding gingiva were key features. Microbiological testing revealed an absence of Actinobacillus actinomycetemcomitans and low levels of other commonly accepted periodontal pathogens. Tests for inflammation, including AST and elastase, were positive prior to therapy and greatly decreased after mechanical root instrumentation. A beneficial effect of non-surgical periodontal therapy was observed in the short-term follow-up.