Subgingival Plaque in Periodontal Health Antagonizes at Toll-Like Receptor 4 and Inhibits E-Selectin Expression on Endothelial Cells.

The ability of the subgingival microbial community to induce an inappropriate inflammatory response ultimately results in the destruction of bone and gingival tissue. In this study, subgingival plaque samples from both healthy and diseased sites in the same individual were obtained from adults with chronic periodontitis and screened for their ability to either activate Toll-like receptor 2 (TLR2) or TLR4 and to antagonize TLR4-specific activation by agonist, Fusobacterium nucleatum LPS. Subgingival plaque from diseased sites strongly activated TLR4, whereas matched plaque samples obtained from healthy sites were significantly more variable, with some samples displaying strong TLR4 antagonism, while others were strong TLR4 agonists when combined with F. nucleatum LPS. Similar results were observed when TLR4 dependent E-selectin expression by endothelial cells was determined. These results are the first to demonstrate TLR4 antagonism from human plaque samples and demonstrate that healthy but not diseased sites display a wide variation in TLR4 agonist and antagonist behavior. The results have identified a novel characteristic of clinically healthy sites and warrant further study on the contribution of TLR4 antagonism in the progression of a healthy periodontal site to a diseased one.

Risk factors that may modify the innate and adaptive immune responses in periodontal diseases.

Plaque-induced periodontal diseases occur in response to the accumulation of dental plaque. Disease manifestation and progression is determined by the nature of the immune response to the bacterial complexes in plaque. In general, predisposing factors for these periodontal diseases can be defined as those factors which retain or hinder the removal of plaque and, depending upon the nature of the immune response to this plaque, the disease will either remain stable and not progress or it may progress and result in chronic periodontitis. In contrast, modifying factors can be defined as those factors that alter the nature or course of the inflammatory lesion. These factors do not cause the disease but rather modify the chronic inflammatory response, which, in turn, is determined by the nature of the innate and adaptive immune responses and the local cytokine and inflammatory mediator networks. Chronic inflammation is characterized by vascular, cellular and repair responses within the tissues. This paper will focus on how common modifying factors, such as smoking, stress, hormonal changes, diabetes, metabolic syndrome and HIV/AIDS, influence each of these responses, together with treatment implications. As treatment planning in periodontics requires an understanding of the etiology and pathogenesis of the disease, it is important for all modifying factors to be taken into account. For some of these, such as smoking, stress and diabetic control, supportive health behavior advice within the dental setting should be an integral component for overall patient management.

Pep19 drives epitope spreading in periodontitis and periodontitis-associated autoimmune diseases.

BACKGROUND AND OBJECTIVE: Epitope spreading is one of valid mechanisms operating in immunopathological processes of infection-induced autoimmune diseases. We hypothesized that the peptide 19 from Porphyromonas gingivalis heat shock protein (HSP) 60 (Pep19) may be the dominant epitope from which epitope-specific immune response to subdominant epitopes may diversify sequentially into autoimmune responses directed at human neoepitopes in P. gingivalis-induced periodontitis and autoimmune diseases. However, the exact feature and mechanism on how Pep19 may drive epitope spreading into human autoantigens in chronic periodontitis or P. gingivalis-induced experimental periodontitis has not been clarified. The present study was performed with the following specific aims: (i) to delineate retrospectively the features of epitope spreading by human cross-sectional analysis; (ii) to demonstrate prospectively the epitope spreading into new antigenic determinants in an ordered, predictable and sequential manner in experimental periodontitis; and (iii) to clarify the mechanism on how immunization with Pep19 may mobilize helper T cells or elicit B-cell responses to human autoantigens and neoantigen. MATERIAL AND METHODS: The study was devised for two independent investigations - a cross-sectional analysis on clinical subjects and a prospective analysis on experimental periodontitis - each being subdivided further into two additional independent observations. Cross-sectional dot immunoblot pattern against a panel of peptides of P. gingivalis HSP60 and human HSP60 was performed among age-dependent healthy subjects and between healthy subjects, patients with chronic periodontitis and patients with autoimmune disease, to identify epitope spreading. A peptide-specific T-cell line was established for phenotype analysis and for proliferation assay to an array of identical peptides. An identical prospective analysis was performed in P. gingivalis-induced experimental periodontitis or in Pep19-immunized mice. Cross-reactivity of anti-Pep19 monoclonal antibody was also investigated. RESULTS: A dominant immune response exclusively to Pep19 prevailed in healthy human subjects (before the age of 40) and mice that persisted in chronic periodontitis and autoimmune diseases without being replaced further by subsequent subdominant epitopes. A sequential epitope spreading provoked by Pep19 to subdominant autoantigen peptide 19 from human HSP60 (Hu19) in most healthy human subjects and mice, and to autoantigen peptide 9 from human HSP60 (Hu9) and neoantigen oxidized low-density lipoprotein (ox-LDL) in P. gingivalis-induced chronic periodontitis and autoimmune diseases could be demonstrated in a reproducible and predictable manner. T-cell proliferative activity to multiple autoantigens Hu19, Hu9 and ox-LDL, and cross-reactivity of anti-Pep19 monoclonal antibody to these epitopes may be proposed as cellular and molecular mechanisms responsible for the phenomenon. Moreover, the predictive value of Pep19 for Hu9 increased remarkably in the disease group when compared with that of the healthy group. CONCLUSION: Taken together, epitope spreading to Hu19, Hu9 and ox-LDL provoked by Pep19 could be proposed as a solid phenomenon observed in P. gingivalis-induced chronic periodontitis and infection-induced autoimmune diseases in a reproducible and predictable manner. T-cell proliferative activity to these peptides and cross-reactivity of anti-Pep19 antibodies to multiple human autoantigens could be proposed as cellular and molecular mechanisms responsible for this phenomenon.

GM-CSF and uPA are required for Porphyromonas gingivalis-induced alveolar bone loss in a mouse periodontitis model.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and urokinase-type plasminogen activator (uPA) can contribute to the progression of chronic inflammatory diseases with possible involvement of macrophages. In this study, we investigated the role of both GM-CSF and uPA in Porphyromonas gingivalis-induced experimental periodontitis using GM-CSF-/- and uPA-/- mice. Intra-oral inoculation of wild-type (WT) C57BL/6 mice with P. gingivalis resulted in establishment of the pathogen in plaque and a significant increase in alveolar bone resorption. The infected mice also exhibited a CD11b(+) CD86(+) macrophage infiltrate into the gingival tissue, as well as P. gingivalis-specific pro-inflammatory cytokine and predominantly IgG2b antibody responses. In comparison, intra-oral inoculation of P. gingivalis did not induce bone resorption and there was significantly less P. gingivalis recovered from plaque in GM-CSF-/- and uPA-/- mice. Furthermore, P. gingivalis did not induce a macrophage gingival infiltrate or activate isolated peritoneal macrophages from the gene-deficient mice. Pro-inflammatory P. gingivalis-specific T-cell cytokine responses and serum interferon-gamma (IFN-γ) and IgG2b concentrations were significantly lower in GM-CSF-/- mice. In uPA-/- mice, T-cell responses were lower but serum IFN-γ and IgG2b levels were comparable with WT mice levels. These results suggest that GM-CSF and uPA are both involved in the progression of experimental periodontitis, possibly via a macrophage-dependent mechanism(s).

Smoking decreases structural and functional resilience in the subgingival ecosystem.

AIMS: Dysbiotic microbial communities underlie the aetiology of several oral diseases, especially in smokers. The ability of an ecosystem to rebound from the dysbiotic state and re-establish a health-compatible community, a characteristic known as resilience, plays an important role in susceptibility to future disease. The present investigation was undertaken to examine the effects of smoking on colonization dynamics and resilience in marginal and subgingival biofilms. MATERIALS AND METHODS: Marginal and subgingival plaque and gingival crevicular fluid samples were collected from 25 current and 25 never smokers with pre-existing gingivitis at baseline, following resolution, after 1, 2 4, 7, 14 and 21 days of undisturbed plaque formation and following resolution. 16S cloning and sequencing was used for bacterial identification and multiplexed bead-based flow cytometry was used to quantify the levels of 27 immune mediators. RESULTS: Smokers demonstrated an early pathogenic colonization that led to sustained pathogen enrichment with periodontal and respiratory pathogens, eliciting a florid immune response. Smokers also demonstrated greater abundance of pathogenic species, poor compositional correlation between marginal and subgingival ecosystems, and significantly greater pro-inflammatory responses following resolution of the second episode of disease. CONCLUSIONS: The ability of the subgingival microbiome to "reset" itself following episodes of disease is decreased in smokers, thereby lowering the resilience of the ecosystem and decreasing its resistance to future disease.

Influence of periodontal disease, Porphyromonas gingivalis and cigarette smoking on systemic anti-citrullinated peptide antibody titres.

BACKGROUND: Anti-citrullinated protein antibody (ACPA) responses may precede clinical onset of rheumatoid arthritis. Porphyromonas gingivalis peptidylarginine deiminase can citrullinate proteins possibly inducing autoimmunity in susceptible individuals. AIM: To determine whether periodontitis, carriage of P. gingivalis, smoking and periodontal therapy influence ACPA titres. METHODS: Serum and plaque samples were collected from 39 periodontitis patients before and after non-surgical periodontal treatment, and from 36 healthy subjects. Carriage of P. gingivalis was determined by PCR of plaque DNA. ACPA was determined by anti-cyclic citrullinated peptide (CCP) enzyme-linked immunosorbent assay (ELISA). Anti-P. gingivalis titres were determined by ELISA. RESULTS: Untreated periodontitis patients had higher anti-CCP antibody titres than healthy controls [three patients (8%) greater than manufacturer suggested assay diagnostic threshold (5 Assay Units/AU) versus none (0%); mean ± SEM: 1.37 ± 0.23 versus 0.40 ± 0.10 AU, p < 0.0001]. Periodontitis patients who smoked demonstrated lower anti-P. gingivalis (15956 ± 4385 versus 2512 ± 1290 Units/ml, p < 0.05), but similar anti-CCP than non-smoking periodontitis patients (smokers: 1.31 ± 0.35; non-smokers: 1.41 ± 0.32 AU). Healthy smokers demonstrated elevated anti-CCP titres (0.75 ± 0.19 AU), at levels between healthy non-smokers (0.15 ± 0.05 AU) and non-smoker periodontitis patients. Six months after periodontal treatment, there were significant reductions in anti-CCP (non-smokers p < 0.05) and anti-P. gingivalis (all participants p < 0.01). CONCLUSION: In subjects with periodontitis, P. gingivalis infection may be responsible for inducing autoimmune responses that characterize rheumatoid arthritis.

Immunological and microbiological findings after the application of two periodontal surgical techniques: a randomized, controlled clinical trial.

AIM: To examine microbiological and immunological alterations following two periodontal surgical techniques, over a 6-month period. MATERIALS AND METHODS: A total of 30 chronic periodontitis patients participated in the present randomized controlled clinical trial and were randomized in two groups. Modified Widman flap (MWF) was applied in the control group and apically positioned flap (APF), without intervention to the bone, in the experimental group. Gingival crevicular fluid samples and subgingival plaque samples from the operated sites were collected at baseline, 6th, 12th and 24th post-operative week. RESULTS: No major differences were noticed in immunological and microbiological profile of patients receiving either modified MWF or APF, for a period of 6 months. CONCLUSIONS: The choice of the periodontal surgical procedure does not seem to affect the immunological and the microbiological profile of patients with chronic periodontitis.

Periodontal pathogen load and increased antibody response to heat shock protein 60 in patients with cardiovascular disease.

AIM: To determine the relationship between periodontal pathogen load and anti-human heat shock protein 60 (hHSP60) antibodies in patients with established cardiovascular disease (CVD). MATERIALS AND METHODS: Participants were cardiovascular patients (n = 74) with a previous hospital admission for myocardial infarction. Concurrent periodontal pathogen load of Porphyromonas gingivalis, Fusobacterium nucleatum, Tannerella forsythia and Aggregatibacter actinomycetemcomitans was determined using quantitative real-time PCR. Serum antibodies to these pathogens, GroEL and hHSP60 were determined using an ELISA. RESULTS: There was a trend for increasing anti-hHSP60 antibody as the number of bacterial species increased. The strongest positive correlations were found between anti-hHSP60 levels and numbers of T. forsythia (r = 0.43; p < 0.001) and between anti-hHSP60 and anti-GroEL levels (r = 0.39; p = 0.001). Patients with extensive periodontal pocketing (≥4 mm) had higher numbers of P. gingivalis and T. forsythia (p < 0.05) and a higher subgingival pathogen load (p < 0.05) than patients with minimal pocketing (≤1 site ≥ 4 mm). They also had significantly elevated anti-hHSP60 levels (p < 0.05). Overall, the highest anti-hHSP60 levels were seen in patients with extensive periodontal pocketing and all four bacterial species. CONCLUSIONS: In cardiovascular patients, a greater burden of subgingival infection with increased levels of P. gingivalis and T. forsythia is associated with modestly higher anti-hHSP60 levels.

[Mechanisms for bone resorption induced by periodontal pathogens].

Periodontitis is the inflammatory disease caused by periodontal pathogens in dental plaque, and progression of this pathological condition is also considered as a major cause of alveolar bone resorption and subsequent tooth depletion. LPS and several kinds of proteinases produced by periodontal pathogens directly destroy periodontal tissues. On the other hand, host defense systems existing in the periodontal tissues exert essential roles in protection of periodontal tissues from bacterial invasion. Immune system divides broadly into 2 categories, innate immune and acquired immune systems. The former is the first defensive barrier against infectious diseases of pathogens, and phagocytic cells including macrophages and neutrophils are involved in this immune system as innate immune function. The latter is the secondary immune system that antigen-presenting cells such as dendritic cells detect smaller pathogens or intracellular pathogens, and antigens which retain as intact proteins on the surfaces of these cells activate T cells and B cells. However, once inflammation becomes persistent with bacteria, these biological defective mechanisms causes breakdown of host innate and acquired immune systems, and subsequent destruction of periodontal tissues. Here we review the mechanisms by which periodontal pathogens cause bone resorption.

Endotoxemia and the host systemic response during experimental gingivitis.

AIM: To assess endotoxemia episodes and subsequent changes in serum inflammatory biomarkers using the experimental gingivitis model. MATERIALS AND METHODS: Data from 50 healthy black and white adult males and females were compared for serum concentrations of endotoxin, and serum biomarkers [neutrophil oxidative activity, interleukin (IL)-1ß, IL-6, IL-8, C-reactive protein (CRP), and fibrinogen] at baseline, at 3 weeks of experimental gingivitis, and after 2 weeks of recovery. Means were compared using repeated measures analysis of variance. RESULTS: Endotoxemia was reported in 56% of the serum samples at 3 weeks of induced gingivitis. At 2 weeks of recovery, endotoxin levels decreased to levels similar to those reported at baseline. Neutrophil oxidative activity increased significantly following 3 weeks of gingivitis versus baseline (p<0.05). In the endotoxin-negative group this increase was associated with the black subjects whereas in the endotoxin-positive group change in neutrophil activity was driven by the female subpopulation. Serum cytokines, CRP, and fibrinogen levels did not change during the study. CONCLUSIONS: Experimental gingivitis was associated with endotoxemia and hyperactivity of circulating neutrophils, but not with changes in systemic levels of cytokines and acute-phase proteins. This may be attributed to the mild nature and the short duration of the induced gingivitis.

Serum high-density lipoprotein cholesterol level associated with the extent of periodontal inflammation in type 1 diabetic subjects.

AIM: High-density lipoprotein (HDL) cholesterol is known for its anti-inflammatory and antioxidant activities in protection against cardiovascular diseases. We investigated whether a protective association also exists between serum HDL and periodontal inflammation in type 1 diabetic subjects (T1DM). METHODS: Plaque and periodontal inflammation (bleeding and PD ≥ 4 mm) were examined in 80 subjects with T1DM. The serum levels of glycosylated haemoglobin (HbA1c, %) and HDL (mmol/l) were determined. Adjusted associations between inflammation and serum HDL were analysed using linear regression analysis. To study the linearity of the association, the subjects were categorized into HDL tertiles (I-III). RESULTS: A statistically significant negative association was observed between serum HDL level and the extent of bleeding and PD ≥ 4 mm. Subjects in HDL tertiles II and III (high HDL) presented significantly fewer inflamed sites when compared with the subjects in tertile I (low HDL), whereas no significant difference in the number of inflamed sites was observed between tertiles II and III. CONCLUSIONS: Based on the finding of a negative association between serum HDL and periodontal inflammation, HDL may be considered a marker of susceptibility to periodontal inflammation. A longitudinal study is needed to verify possible causal relationship between serum HDL and inflammation.

Nexus between COVID-19 and periodontal disease.

Over the past several decades, studies have demonstrated the existence of bi-directional relationships between periodontal disease and systemic conditions. Periodontitis is a polymicrobial and multifactorial disease involving both host and environmental factors. Tissue destruction is primarily associated with hyperresponsiveness of the host resulting in release of inflammatory mediators. Pro-inflammatory cytokines play a major role in bacterial stimulation and tissue destruction. In addition, these cytokines are thought to underlie the associations between periodontitis and systemic conditions. Current research suggests that increased release of cytokines from host cells, referred to as the cytokine storm, is associated with disease progression in patients with coronavirus disease 2019 (COVID-19). An intersection between periodontitis and pulmonary disease is biologically plausible. Hence, we reviewed the evidence linking COVID-19, cytokines, and periodontal disease. Plaque control is essential to prevent exchange of bacteria between the mouth and the lungs, reducing the risk of lung disease. Understanding these associations may help identify individuals at high risk and deliver appropriate care at early stages.

Relationships between subgingival microbiota and GCF biomarkers in generalized aggressive periodontitis.

AIM: To examine relationships between subgingival biofilm composition and levels of gingival crevicular fluid (GCF) cytokines in periodontal health and generalized aggressive periodontitis (GAP). MATERIALS AND METHODS: Periodontal parameters were measured in 25 periodontally healthy and 31 GAP subjects. Subgingival plaque and GCF samples were obtained from 14 sites from each subject. Forty subgingival taxa were quantified using checkerboard DNA-DNA hybridization and the concentrations of eight GCF cytokines were measured using Luminex. Cluster analysis was used to define sites with similar subgingival microbiotas in each clinical group. Significance of differences in clinical, microbiological and immunological parameters among clusters was determined using the Kruskal-Wallis test. RESULTS: GAP subjects had statistically significantly higher GCF levels of interleukin-1beta (IL-1beta) (p<0.001), granulocyte-macrophage colony-stimulating factor (GM-CSF) (p<0.01) and IL-1beta/IL-10 ratio (p<0.001) and higher proportions of Red and Orange complex species than periodontally healthy subjects. There were no statistically significant differences in the mean proportion of cytokines among clusters in the periodontally healthy subjects, while the ratio IL-1beta/IL-10 (p<0.05) differed significantly among clusters in the aggressive periodontitis group. CONCLUSIONS: Different subgingival biofilm profiles are associated with distinct patterns of GCF cytokine expression. Aggressive periodontitis subjects were characterized by a higher IL-1beta/IL-10 ratio than periodontally healthy subjects, suggesting an imbalance between pro- and anti-inflammatory cytokines in aggressive periodontitis.

IL-6 and IL-8 levels in GCF of the teeth supporting fixed partial denture.

OBJECTIVES: To evaluate the gingival crevicular fluid (GCF) contents of interleukin-6 (IL-6) and interleukin-8 (IL-8) and the clinical parameters of the teeth supporting fixed partial denture (FPD) and the contralateral teeth and to assess the effect of scaling and root planning (SRP) on clinical parameters and the GCF levels of cytokines. MATERIALS AND METHODS: The study population included 23 patients. Probing depth (PD), clinical attachment level (CAL), plaque index (PI), and gingival index (GI) were recorded, and GCF samples were collected for analysis of cytokine levels from the teeth with FPD (Test Group), the contralateral teeth (Control Group) of each participant at baseline. After initial measurements, all participants received primary phase of non-surgical treatment including oral hygiene instruction and scaling and root planning (SRP). At the 1st month and the 3rd month after SRP, these procedures were repeated. RESULTS: In both groups, all clinical parameters and the total amount of IL-8 showed decreases from initial to the 3rd month (P < 0.05), but from the 1st month to the 3rd month; PD, PI, and GI values significantly increased in the test group (P < 0.05). CONCLUSION: The non-surgical periodontal treatment reduced the total amount of IL-8, not IL-6, and the clinical parameters of the teeth with FPD and contralateral teeth. But, there was a trend to the higher levels of PD, PI, and GI in the teeth with FPD. Therefore, a regular program for dental prophylaxis is also important for the maintenance of periodontal health in patients with FPD.

Correlation Between Oral Health and Systemic Inflammation (COHESION): A Randomized Pilot Follow-Up Trial of a Plaque-Identifying Toothpaste.

BACKGROUND: Inflammation is intimately involved in the pathogenesis of atherosclerosis and is accurately measured by high-sensitivity C-reactive protein (hs-CRP), a sensitive marker for future risk of cardiovascular disease. The Correlation between Oral Health and Systemic Inflammation (COHESION) trial was designed to test the hypothesis that PlaqueHD, a plaque-identifying toothpaste, reduces hs-CRP. METHODS: The trial was designed initially to include 132 subjects with hs-CRP between 2.0 and 10.0 mg/L but instead randomized 112 between 0.5 and 10.0, of which 103 had baseline and follow-up data and comprised the intention-to-treat sample. Of these, a prespecified subgroup analysis included 40 with baseline hs-CRP >2.0 and all hs-CRP <10. Because the distribution of hs-CRP was skewed toward higher values, to achieve normality assumptions, the significance of changes in hs-CRP between groups over time was tested on log-transformed data using a mixed effects analysis of variance. RESULTS: The intention-to-treat analysis showed no significant differences between the PlaqueHD and placebo group (P = .615). The prespecified subgroup analysis showed a significant difference between the PlaqueHD and placebo group (P = .047). Results of the analysis showed a reduction in hs-CRP at follow-up of 0.58 in the PlaqueHD and an increase of 0.55 in the placebo group. CONCLUSIONS: These findings are compatible with those of a prior pilot trial that also suggested benefits only in subjects with baseline elevations. Future trials targeting reductions of hs-CRP levels should randomize subjects with baseline hs-CRP between 2.0 and 10.0 mg/L.

Orally administered ovine serum immunoglobulins modulate dental plaque in cats.

The effects of orally administered ovine serum immunoglobulin on dental plaque and associated oral immunity in cats were investigated. The two treatment groups consisted of 1) cats that were fed unsupplemented kibble (control diet) and 2) cats that were fed the same kibble but coated with a freeze-dried ovine serum immunoglobulin preparation (ovine Ig) (test diet). The adult cats were randomly allocated to one of the two diets (n = 15) and received their respective kibble for a 28-day experimental period. When compared to the ovine Ig-supplemented kibble, cats consuming the unsupplemented kibble had significantly (p < 0.05) higher dental plaque scores. Cat IgA and IgG concentrations in the saliva and serum were significantly (p < 0.05) higher for cats fed the unsupplemented kibble when compared to cats receiving the ovine Ig supplement. Similarly, myeloperoxidase activity in the saliva was significantly (p < 0.05) higher for cats fed the unsupplemented kibble when compared to cats receiving the Ig-supplement. Orally administered ovine serum Ig positively influenced oral health and oral immunity in cats as evidenced by preventing an increase of dental plaque formation, salivary and serum IgA and IgG concentrations and salivary myeloperoxidase activity.

Porphyromonas gingivalis RgpA-Kgp proteinase-adhesin complexes penetrate gingival tissue and induce proinflammatory cytokines or apoptosis in a concentration-dependent manner.

The RgpA-Kgp proteinase-adhesin complexes of Porphyromonas gingivalis were observed, using immunostaining, in human gingival tissue associated with periodontitis but not in healthy tissue. The staining pattern suggested a concentration gradient from the subgingival plaque into the subjacent gingival connective tissue. Intense immunostaining was observed in areas displaying gross disturbance of tissue architecture. P. gingivalis cells and the RgpA-Kgp complexes at low concentrations were shown to stimulate secretory intercellular adhesion molecule 1, interleukin-8 (IL-8), IL-6, and macrophage chemoattractant protein secretion from cultured human epithelial (KB) and fibroblast (MRC-5) cells. However, at high concentrations a reduction in the level of these mediators was observed. In contrast, macrophage inflammatory protein 1alpha and IL-1alpha were stimulated only at high P. gingivalis cell concentrations. P. gingivalis cells and the RgpA-Kgp complexes were shown to induce apoptosis in KB and MRC-5 cells in a time- and dose-dependent manner. These data suggest that the RgpA-Kgp complexes penetrate the gingival connective tissue; at low concentrations distal from the plaque the complexes stimulate the secretion of proinflammatory mediators, while at high concentrations proximal to the plaque they induce apoptosis and attenuate the secretion of proinflammatory mediators.

Bone resorbing activity in supernatant fluid from cultured human peripheral blood leukocytes.

A new soluble mediator was found in supernatant fluid from cultures of human peripheral blood leukocytes that were stimulated by phytohemagglutinin, or by antigenic material present in human dental plaque deposits. This soluble Jactor produced bone resorption in organ cultures of fetal rat bones as measured by increased release of calcium-45, and also increased the number of active osteoclasts.

Cytokines in gingival crevicular fluid of adolescents and young adults.

BACKGROUND/AIM: The purpose of this study was to compare the levels of the cytokines interleukin-1beta (IL-1beta), IL-4, and IL-8 in the gingival crevicular fluid (GCF) of adolescents and young adults. METHODS: Twenty-five adolescents aged between 14 and 16 years (Group A) and 20 periodontally healthy young adults aged between 25 and 35 years (Group B) were selected from two private dental clinics limited to pedodontics and periodontics respectively in Piraeus Greece. All subjects were systemically healthy. Clinical examination included probing pocket depth (PPD), presence or absence of plaque, and bleeding on probing (BOP). GCF was collected from four sites per subject. IL-1beta, IL-4, and IL-8, measured as total amounts (pg/30 s), were evaluated in 180 samples using a commercially available sandwich enzyme-linked immunosorbent assay. RESULTS: IL-1beta mean levels of Groups A and B were adjusted for BOP and PPD. Differences of IL-1beta mean levels between the two age groups were statistically significant (F = 50.245, P < 0.001) in favour of Group A. Adolescents showed statistically significantly lower mean levels of IL-4 than young adults in the presence of BOP (F = 10.690, P = 0.001). There was no statistically significant difference between adolescents and adults for the means of IL-8 adjusted for BOP and plaque presence (F = 2.032, P = 0.161). CONCLUSIONS: Within the limits of this study the differences reported in mean levels of IL-1beta and IL-4 may be attributed to the different age status.

Real-time polymerase chain reaction to determine the prevalence and copy number of epstein-barr virus and cytomegalovirus DNA in subgingival plaque at individual healthy and periodontal disease sites.

BACKGROUND: Detection of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in plaque from patients with periodontal disease provides support for the theory that these viruses play a role in the pathogenesis of periodontitis. This study sought to further define this relationship by determining the prevalence of these viruses at individual disease and healthy sites of patients with periodontal disease and to determine whether the presence and amount of viral DNA correlate with disease severity. METHODS: Subgingival plaque from three healthy and three disease sites of 65 patients who had chronic periodontitis were evaluated for the presence and amount of EBV, CMV, and Fusobacterium nucleatum DNA using real-time polymerase chain reaction. Patient serum was evaluated for antibodies against EBV and CMV using enzyme-linked immunosorbent assays. RESULTS: EBV DNA was detected in 18.5% of subgingival plaque samples (72/390) and in at least one of the six plaque samples in 44.6% (29/65) of the patients. CMV DNA was detected in one plaque sample (0.3%). EBV was significantly more prevalent in disease sites (28.2%; 55/195) than in healthy sites (8.7%; 17/195; P = 0.002). However, neither EBV prevalence nor its amount correlated with increased probing depth >5 mm or attachment loss >2 mm, whereas the amount of F. nucleatum DNA did. Sites positive for EBV had a median copy number of eight. Antibodies against EBV and CMV were detected in 85.7% and 78.6% of persons evaluated, respectively. CONCLUSION: EBV was infrequent and CMV was rarely present in individual subgingival sites affected by chronic periodontitis.