Periodontitis is an infectious process characterized by inflammation affecting the supporting structures of the teeth. Porphyromonas gingivalis is a major oral bacterial species implicated in the pathogenesis of periodontitis. Processing of interleukin (IL)-1 family cytokines is regulated by an intracellular innate immune response system, known as the NALP3 [nacht domain-, leucine-rich repeat-, and pyrin domain (PYD)-containing protein 3] inflammasome complex. The aim of the present study was to investigate by quantitative real-time polymerase chain reaction (PCR) the mRNA expression of NALP3, its effector molecule apoptosis associated speck-like protein (ASC), its putative antagonist NLRP2 (NLR family, PYD-containing protein 2), IL-1β and IL-18 (i) in gingival tissues from patients with gingivitis (n = 10), chronic periodontitis (n = 18), generalized aggressive periodontitis (n = 20), as well as in healthy subjects (n = 20), (ii) in vitro in a human monocytic cell line (Mono-Mac-6), in response to P. gingivalis challenge for 6 h. The clinical data indicate that NALP3 and NLRP2, but not ASC, are expressed at significantly higher levels in the three forms of inflammatory periodontal disease compared to health. Furthermore, a positive correlation was revealed between NALP3 and IL-1β or IL-18 expression levels in these tissues. The in vitro data demonstrate that P. gingivalis deregulates the NALP3 inflammasome complex in Mono-Mac-6 cells by enhancing NALP3 and down-regulating NLRP2 and ASC expression. In conclusion, this study reveals a role for the NALP3 inflammasome complex in inflammatory periodontal disease, and provides a mechanistic insight to the host immune responses involved in the pathogenesis of the disease by demonstrating the modulation of this cytokine-signalling pathway by bacterial challenge.

Periodontal diseases are among the most prevalent worldwide, but largely silent, chronic diseases. They affect the tooth-supporting tissues with multiple ramifications on life quality. Their early diagnosis is still challenging, due to lack of appropriate molecular diagnostic methods. Saliva offers a non-invasively collectable reservoir of clinically relevant biomarkers, which, if utilized efficiently, could facilitate early diagnosis and monitoring of ongoing disease. Despite several novel protein markers being recently enlisted by discovery proteomics, their routine diagnostic application is hampered by the lack of validation platforms that allow for rapid, accurate and simultaneous quantification of multiple proteins in large cohorts. Here we carried out a pipeline of two proteomic platforms; firstly, we applied open ended label-free quantitative (LFQ) proteomics for discovery in saliva (n = 67, including individuals with health, gingivitis, and periodontitis), followed by selected-reaction monitoring (SRM)-targeted proteomics for validation in an independent cohort (n = 82). The LFQ platform led to the discovery of 119 proteins with at least 2-fold significant difference between health and disease. The 65 proteins chosen for the subsequent SRM platform included 50 functionally related proteins derived from the significantly enriched processes of the LFQ data, 11 from literature-mining, and four house-keeping ones. Among those, 60 were reproducibly quantifiable proteins (92% success rate), represented by a total of 143 peptides. Machine-learning modeling led to a narrowed-down panel of five proteins of high predictive value for periodontal diseases with maximum area under the receiver operating curve >0.97 (higher in disease: Matrix metalloproteinase-9, Ras-related protein-1, Actin-related protein 2/3 complex subunit 5; lower in disease: Clusterin, Deleted in Malignant Brain Tumors 1). This panel enriches the pool of credible clinical biomarker candidates for diagnostic assay development. Yet, the quantum leap brought into the field of periodontal diagnostics by this study is the application of the biomarker discovery-through-verification pipeline, which can be used for validation in further cohorts.

Background: Coronary heart disease is the leading cause of morbidity and mortality throughout the world. Well‐known risk factors independently or combined participate in both myocardial infarction and atherosclerosis. Recent data have shown that viral and bacterial infections may also contribute to the acute thromboembolic events. The aim of the present study was to investigate the possible association between periodontal health and coronary heart disease in patients with acute myocardial infarction and chronic coronary heart disease.Methods: A total of 120 patients, 60 with acute myocardial infarction (AMI) and 60 with chronic coronary heart disease (CCHD) were included in this study. The patients in the AMI group (50 men and 10 women; mean age 53.8 ± 9.5 years) were admitted to the Department of Cardiology, University Hospital of Ege because of AMI. The CCHD patients group (42 men and 18 women; mean age 58.5 ± 11.6 years) had no documented history of recent acute coronary events. All patients were clinically examined and completed a medical questionnaire. Missing teeth, restorations, probing depth (PD) and bleeding on probing (BOP) were recorded. Blood samples were taken on admission for measurements of serum total cholesterol, triglycerides, high density lipoprotein cholesterol (HDL‐cholesterol), low density lipoprotein cholesterol (LDL‐cholesterol), and fasting blood glucose level. Sample proportions were compared by chi square test, quantitative variables with Student t test. The relation of clinical parameters and conventional risk factors to AMI was assessed with logistic regression analysis.Results: The number of sites with PD ≥4 mm, the percentage of sites exhibiting BOP, smoking status, total cholesterol, LDL‐cholesterol, and triglycerides were statistically different between AMI and CCHD groups (P <0.05). Logistic regression analysis showed that the percentage of sites exhibiting BOP, the number of sites with PD ≥4, the number of restorations, smoking status, and triglycerides levels were significantly associated with AMI (P <0.05).Conclusions: The results of this study indicate that periodontal disease may be associated with acute myocardial infarction. To our knowledge, this is the first study that reports the importance of periodontal health in the occurrence of acute myocardial infarction in a Turkish population. We propose that prospective randomized studies are needed to determine whether periodontal disease is a risk factor in the occurrence of acute myocardial infarction. J Periodontol 2000;71:1882‐1886.

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 lowdose 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. J Periodontol 2004;75:106‐115.