The utility of gingival crevicular fluid matrix metalloproteinase-8 response patterns in prediction of site-level clinical treatment outcome.

BACKGROUND: Different gingival crevicular fluid (GCF) matrix metalloproteinase (MMP)-8 response patterns were studied among non-smoking and smoking patients with chronic periodontitis (CP) and generalized aggressive periodontitis (GAgP) to test the utility of GCF MMP-8 levels predicting the site-level treatment outcome. METHODS: Data from four independent longitudinal studies were combined. Altogether, the studies included 158 periodontal sites from 67 patients with CP and 32 patients with GAgP, and GCF samples were collected at baseline, after the treatment, and during the 6-month maintenance period. All GCF samples were analyzed by immunofluorometric assay for MMP-8. Different site-level MMP-8 response patterns were explored by the cluster analysis. Most optimal MMP-8 cutoff levels were searched with receiver operating characteristic analyses, and the predictive utility of defined levels was tested. RESULTS: Distinct types of MMP-8 response patterns were found in both smokers and non-smokers. MMP-8 levels exceeding the optimal cutoff levels separately defined for smokers and non-smokers indicated increased risk for compromised treatment outcome at baseline and during the maintenance period. Seventy-one percent of non-smokers (positive likelihood ratio of 4.22) and 88% of smokers (positive likelihood ratio of 5.00) with positive test results at both baseline and the maintenance period had compromised treatment outcome. The double-positive result indicated 46% and 39% point risk increase for the compromised outcome, respectively. CONCLUSION: GCF MMP-8 analysis with defined cutoff levels could be used to predict the site-level treatment outcome and for longitudinal monitoring of the disease status during the maintenance period.

Gingival crevicular fluid matrix metalloproteinase-8 levels predict treatment outcome among smokers with chronic periodontitis.

BACKGROUND: Molecular biomarkers are needed for diagnostic use in periodontal diseases. The aim of this study is to explore different gingival crevicular fluid (GCF) matrix metalloproteinase-8 (MMP-8) patterns in smokers and non-smokers with chronic periodontitis (CP) and test the utility of baseline GCF MMP-8 levels in predicting categorically assessed treatment outcomes. METHODS: The study population comprised 15 patients with CP (five non-smokers and 10 smokers). GCF sampling of five to seven periodontal sites per patient was done at baseline, post-treatment, and bimonthly during the maintenance period from 8 to 12 months. GCF MMP-8 levels were measured with an immunofluorometric assay. MMP-8 response patterns were explored by cluster analysis. The ability of baseline MMP-8 levels to predict categorical treatment outcomes was analyzed with receiver operating characteristic curves. RESULTS: GCF MMP-8 response patterns could be clustered into two different site profiles among both smokers and non-smokers. Smoker site profiles 1 and 2 had significantly different clinical attachment level and gingival recession changes by the end of the maintenance period. In smoker sites, baseline MMP-8 levels significantly predicted the categorical treatment outcome. CONCLUSIONS: Baseline GCF MMP-8 levels strongly predict how MMP-8 levels behave during the maintenance period. In smoker sites, high baseline MMP-8 levels indicate weak treatment response.

Differential expression of mitogen activating protein kinases in periodontitis.

AIM: Following toll-like receptor (TLR) engagement, lipopolysaccharide (LPS) can stimulate the expression of pro-inflammatory cytokines thus activating the innate immune response. The production of inflammatory cytokines results, in part, from the activation of kinase-induced signalling cascades and transcriptional factors. Of the four distinct classes of mitogen-activated protein kinases (MAPK) described in mammals, p38, c-Jun N-terminal activated kinases (JNK1-3) and extracellular activated kinases (ERK1,2) are the best studied. Previous data have established that p38 MAPK signalling is required for inflammation and bone loss in periodontal disease pre-clinical animal models. MATERIALS & METHODS: In this study, we obtained healthy and diseased periodontal tissues along with clinical parameters and microbiological parameters. Excised fixed tissues were immunostained with total and phospho-specific antibodies against p38, JNK and ERK kinases. RESULTS: Intensity scoring from immunostained tissues was correlated with clinical periodontal parameters. Rank correlations with clinical indices were statistically significantly positive (p-value < 0.05) for total p38 (correlations ranging 0.49-0.68), phospho-p38 (range 0.44-0.56), and total ERK (range 0.52-0.59) levels, and correlations with JNK levels also supported association (range 0.42-0.59). Phospho-JNK and phospho-ERK showed no significant positive correlation with clinical parameters of disease. CONCLUSION: These data strongly implicate p38 MAPK as a major MAPK involved in human periodontal inflammation and severity.

Longitudinal evaluation of GCF MMP-3 and TIMP-1 levels as prognostic factors for progression of periodontitis.

BACKGROUND: To determine whether matrix metalloproteinase-3 (MMP-3) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in gingival crevicular fluid (GCF) could serve as prognostic factors for the progression of periodontitis, we monitored GCF MMP-3 and TIMP-1 and periodontal status of selected sites in 40 medically healthy subjects over a 6-month period. METHOD: Clinical measurements including gingival index (GI), plaque index, bleeding on probing, suppuration, probing depth (PD), attachment loss (AL), and GCF samples were taken from 2 healthy sites (including sites with gingival recession, GI=0 PD < or =3 mm; AL < or =2 mm) and 2 periodontitis sites (GI > or =1; PD > or =5 mm; AL > or =3 mm) of each patient at baseline, 3-month and 6-month visits by means of sterile paper strips. GCF levels of MMP-3 and TIMP-1 were determined by sandwich ELISA assays. RESULTS: The mean amounts of MMP-3 and TIMP-1 in diseased sites were significantly higher than in healthy sites (p<0.0001). Significantly higher GCF levels of MMP-3 and TIMP-1 were found at progressing sites than in nonprogressing periodontitis sites (0.001 or =2 mm loss of attachment during 6- month study period. GCF levels of MMP-3 were highly correlated with clinical measurements taken at baseline, 3-month and 6-month visits (p<0.001). TIMP-1 levels were only moderately correlated with probing depth and attachment level (p<0.01). Step-wise multiple regression analysis was performed to construct models for the prediction of probing depth and attachment loss increases. The most parsimonious regression models which had the best R2 values included the following variables and accounted for the indicated % of variability. The regression model for the prediction of probing depth increase included MMP-3, smoking pack-years, TIMP-1 and accounted for 53% of the variability. The best model for the prediction of attachment loss increase included MMP-3, smoking pack-years, age, TIMP-1 and explained 59% of the variability. CONCLUSION: These data indicate that sites with high GCF levels of MMP-3 and TIMP-1 are at significantly greater risk for progression of periodontitis.

Loss of attachment in the marginal periodontium of the rat incisor under non-inflammatory conditions. Expression of alkaline phosphatase activity. Experimental Oral Biology Group.

Alkaline phosphatase (ALP) has been suggested to play a role in acellular cementum formation and maintenance of periodontal attachment. In an attempt to determine whether changes in attachment level are associated with altered expression of ALP-activity in the periodontium we induced natural loss of attachment in rats by pinning the lower incisor to the jaw bone. Previous studies have shown that this procedure results in regressive changes in the marginal periodontium without any inflammatory response. Six months after blockage of eruption the attachment level on the experimental (right) side had shifted about 700 microm in the apical direction. On the control (left) side the apical termination of the junctional epithelium had remained stationary with respect to the alveolar crest. Our observations have shown that during the first few weeks of the experiment loss of attachment is accompanied by considerable reduction of ALP-activity in the supracrestal part of the periodontium. At later time intervals, however, no distinct relation was found between apical migration of junctional epithelium and loss of ALP-activity in the supracrestal region, indicating that the two phenomena are not directly related to each other. The domain of the ALP-positive fibroblasts in the supracrestal extension of the periodontal ligament decreased in size and was replaced by ALP-negative connective tissue cells probably coming from the outer gingival domain. Since at all time intervals a distinct demarcation could be observed between the ALP-positive and ALP-negative areas, we interpret our data as indicating that ligament and gingival cells do not mix.