In vitro cytokine responses to periodontal pathogens: generalized aggressive periodontitis is associated with increased IL-6 response to Porphyromonas gingivalis

TNF-α promotes expression of inflammatory factors by upregulating nicotinamide adenine dinucleotide phosphate oxidase-2 expression in human gingival fibroblasts

Background/purpose

Periodontitis is a chronic infectious disease. The oxidative stress environment can cause or exacerbate the inflammation in periodontitis. Nicotinamide adenine dinucleotide phosphate oxidase (NOX) may be the most important source of reactive oxygen species (ROS) in periodontal tissues. The pathological mechanism of periodontitis may be related to the increased ROS caused by enhanced NOX activity. The purpose was to investigate the effect of tumor necrosis factor (TNF-α) on inflammatory cytokines and ROS, and the role of NOX-2 in human gingival fibroblasts (HGFs).

Materials and methods

HGFs were cultured and divided into the normal control group (NC group) and the inflammatory model group (TNF-α group) induced by 10 ng/ml TNF-α. Thereafter, NOX-2 siRNA was used to knock down NOX-2 gene expression. Quantitative real-time PCR was applied to detect IL-6, MCP-1, and NOX-2 mRNA levels. The levels of IL-6 and MCP-1 protein were examined by ELISA. The level of NOX-2 was evaluated by Western blot. ROS expression was measured by the fluorescence microplate.

Results

The mRNA and protein expression levels of IL-6, MCP-1, and NOX-2 were significantly increased, and the expression of ROS was significantly elevated in response to 10 ng/ml TNF-α. Compared with the si-NC group, the mRNA and protein expression levels of IL-6 and MCP-1 were significantly down-regulated and ROS expression was significantly decreased in the si-NOX2 group stimulated by 10 ng/ml TNF-α.

Conclusion

TNF-α promotes the expression of NOX-2 in human gingival fibroblasts and enhances the expression of inflammatory factors and ROS in human gingival fibroblasts through the upregulation of NOX-2 partly.

Smoking negatively impacts the clinical, microbiological, and immunological treatment response of young adults with Grade C periodontitis

OBJECTIVE

This study aimed to investigate the influence of smoking on clinical, microbiological and immunological parameters in young adult with stage III-IV Grade C periodontitis after full-mouth ultrasonic debridement (FMUD) associated with Amoxicillin and Metronidazole (AMX + MTZ), comparing smokers (PerioC-Y-Smk) with non-smokers (PerioC-Y-NSmk).

MATERIALS AND METHODS

Fifteen PerioC-Y-NSmk and 14 PerioC-Y-Smk patients underwent FMUD associated with AMX + MTZ for 10 days. All parameters were collected at baseline and 3 and 6 months after treatment. Plaque index (PI), bleeding on probing (BoP), probing depth (PD), clinical attachment level (CAL)- the primary variable-, and gingival recession (GR) were clinically assessed. The impact of PI on CAL change at 6-month was verified by a regression analysis. Samples of the subgingival biofilm was collected for detection of levels of Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Porphyromonas gingivalis (P.gingivalis), Tannerella forsythia (T. forsythia), and Fusobacterium nucleatum ssp (F. nucleatum), and were analyzed by real-time qPCR; gingival crevicular fluid was collected for detection of levels of interleukin (IL)-1β, IL-4, IL-6, IL-10, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ, which were analyzed using an enzyme immunoassay.

RESULTS

PerioC-Y-Smk had significantly higher PI, BOP, and GR at baseline compared to non-smokers (p < .05). PerioC-Y-Smk presented higher PD, CAL, and GR at 3 and 6 months (p < .05) compared with PerioC-Y-NSmk in the same periods; PI negatively affected CAL gain in PerioC-Y-NSmk at 6-month follow-up (p = .052) and did not impact on clinical response in PerioC-Y-Smk (p = .882). Lower levels of IFN-γ, IL1-β, and IL-4 were observed at 3 months in the PerioC-Y-NSmk (p < .05) compared with PerioC-Y-Smk. Lower proportions of P. gingivalis were observed in PerioC-Y-NSmk at baseline and at 3 months (p < .05) and lower proportions of F. nucleatum were observed at 6 months, in the PerioC-Y-NSmk (p < .05).

CONCLUSIONS

PerioC-Y-Smk presents an unfavorable clinical, microbiological, and immunological response after 3 and 6 months after FMUD associated with AMX + MTZ.

CLINICAL RELEVANCE

Smoking worsens periodontal condition of young treated adults presenting stage III/IV Grade C periodontitis.

Peripheral T helper cell profiles during management of periodontitis

AIM

Periodontitis has been associated with other systemic diseases with underlying inflammation responsible for the shared link. This study evaluated longitudinal variation in peripheral T helper cells in periodontitis patients undergoing management over 1 year.

MATERIALS AND METHODS

Periodontal parameters and peripheral blood mononuclear cells (PBMCs) were collected from 54 periodontitis patients at baseline, and 3-, 6- and 12-months post-treatment and 40 healthy controls. IFN-γ⁺ , IL-4⁺ , IL-17⁺ and Foxp3⁺ and their double-positive expression were identified in CD4⁺ and TCRαβ⁺ cells using flow cytometry. PBMCs were incubated with P. gingivalis, and IFN-γ, IL-4, IL-17 and IL-10 in cell supernatant were measured by ELISA. Cells and cytokines were also assessed based on clinical response to treatment where good (<10% of sites), moderate (10-20%) and poor (>20%) treatment outcome (TxO) groups had probing depths of ≥5 mm at study conclusion.

RESULTS

IFN-γ⁺ cells were lower at baseline, and 3- and 6-months compared to health, whereas Foxp3⁺ cells were increased at 12-months compared to all preceding timepoints and health. The good TxO group showed treatment-related variation in IFN-γ⁺ and Foxp3⁺ cells, whereas the poor TxO group did not. IFN-γ and IL-17 cytokine expression in cell supernatants was significantly lower at baseline compared to health, and IFN-γ and IL-10 showed treatment-related decrease.

CONCLUSION

This study suggests that IFN-γ⁺ and Foxp3⁺ cells may have a role in the systemic compartment in periodontitis. Periodontal management has local and systemic effects, and thus, assessment and management of periodontitis should form an integral part of overall systemic health.

Association of adipokines with rheumatic disease activity indexes and periodontal disease in patients with early rheumatoid arthritis and their first-degree relatives

OBJECTIVE

To evaluate the adipokine levels in early rheumatoid arthritis (eRA) and first-degree relatives (FDR) of patients with RA and establish their association with rheumatic disease activity and periodontal variables.

METHOD

A cross-sectional study with eRA patients, FDR and a healthy population. Adipokine levels, clinical, joint radiological indexes and periodontal variables were evaluated. A descriptive, bivariate analysis was performed based on the adipokine levels by χ² , Fisher's test and Mann-Whitney U test. A logistic regression was made for associations.

RESULTS

High leptin levels were associated with the diagnosis of eRA (odds ratio [OR] = 2.79; 95% CI 1.54-5.07). Early rheumatoid arthritis with high adiponectin levels was less likely to have Multidimensional Health Assessment Questionnaire score >3, body mass index (BMI) >25 and Routine Assessment of Patient Index Data 3 score >12 (OR = 0.16; 95% CI 0.03-0.72). Early rheumatoid arthritis was more likely to present high leptin and interleukin (IL)6 levels with low adiponectin simultaneously (OR = 5.03; 95% CI 1.05-24.0). High leptin levels were associated with the FDR adjusted for IgG2 Porphyromonas gingivalis, swollen joints, P gingivalis and low IL6 (OR = 2.57; 95% CI 1.14-5.95).

CONCLUSION

High adipokine levels in eRA may modulate the disease activity. Having more than 1 adipokine at high serum levels is associated with increased disability, disease activity and BMI, indicating that RA is controlled by adiponectin levels in the early stages of the disease. High leptin levels, presence of P gingivalis and swollen joints may be the factors associated with the development of RA in FDR.

Tobacco-induced suppression of the vascular response to dental plaque

Cigarette smoking presents oral health professionals with a clinical and research conundrum: reduced periodontal vascular responsiveness to the oral biofilm accompanied by increased susceptibility to destructive periodontal diseases. This presents a significant problem, hampering diagnosis and complicating treatment planning. The aim of this review is to summarize contemporary hypotheses that help to explain mechanistically the phenomenon of a suppressed bleeding response to dysbiotic plaque in the periodontia of smokers. The influence of smoke exposure on angiogenesis, innate cell function, the production of inflammatory mediators including cytokines and proteases, tobacco-bacteria interactions, and potential genetic predisposition are discussed.

Cholesterol crystals enhance TLR2- and TLR4-mediated pro-inflammatory cytokine responses of monocytes to the proatherogenic oral bacterium Porphyromonas gingivalis

Cholesterol deposits and pro-inflammatory cytokines play an essential role in the pathogenesis of atherosclerosis, a predominant cause of cardiovascular disease (CVD). Epidemiological evidence has linked periodontal disease (PD) with atherosclerotic CVD. Accordingly, viable periodontal pathogens, including Porphyromonas gingivalis, have been found in atherosclerotic plaques in humans and mice. We aimed to determine whether cholesterol crystals (CHCs) and oral bacteria synergize in the stimulation of human monocytes. Incubation of human monocytes with CHCs induced secretion of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, and IL-8. Moreover, CHCs markedly enhanced secretion of IL-1β by monocytes stimulated with the toll-like receptor (TLR) 4 agonist Escherichia coli lipopolysaccharide (LPS), and the TLR2 agonist Staphylococcus aureus lipoteichoic acid. Notably, CHCs also enhanced IL-1β secretion induced by P. gingivalis LPS and IL-1β secretion induced by whole P. gingivalis bacteria. This enhancement was abrogated by the NLRP3 inflammasome inhibitors Z-YVAD-FMK and glibenclamide. CHCs had no effect on cytokine production induced by P. gingivalis gingipains. Taken together, our findings support that CHCs, via stimulation of NLRP3 inflammasomes, act in synergy with the periodontal pathogen P. gingivalis to promote monocyte secretion of pro-atherogenic cytokines.

Do leprosy and tuberculosis generate a systemic inflammatory shift? Setting the ground for a new dialogue between experimental immunology and bioarchaeology

It is possible that during long lasting chronic infections such as tuberculosis (TB) and leprosy individuals who generate a stronger immune response will produce a chronic shift in the systemic levels of inflammatory proteins. Consequently, the systemic immunological shift could affect inflammatory responses against other persistent pathogens such as Porphyromonas gingivalis associated with periodontal disease (PD).

OBJECTIVE

To determine if in vitro exposure to Mycobacterium tuberculosis or M. leprae lysates impacts subsequent immune responses to P. gingivalis; and to propose a new dialogue between experimental immunology and paleopathology.

MATERIAL AND METHODS

We sequentially (2 days protocol) exposed peripheral blood mononuclear cells (PBMCs) from healthy donors to bacterial lysates either from M. tuberculosis, or M. leprae, or P. gingivalis. After collecting all supernatants, we measured the expression of immune proteins TNFα and IFNγ using an enzyme-linked immunosorbent assay.

RESULTS

Early exposure (day 1) of PBMCs to M. leprae or M. tuberculosis lysates induces an inflammatory shift detected by the increase of TNFα and IFNγ when the same cells are subsequently (day 2) exposed to oral pathogen P. gingivalis.

DISCUSSION

By extrapolating these results, we suggest that chronic infections, such as TB and leprosy, could generate a systemic immunological shift that can affect other inflammatory processes such the one present in PD. We propose that the presence and severity of PD should be explored as a proxy for inflammatory status or competence when reconstructing the health profile in past populations.

T helper cells from aggressive periodontitis patients produce higher levels of interleukin-1 beta and interleukin-6 in interaction with Porphyromonas gingivalis

OBJECTIVE

In this study, we analyzed the production of Interleukin-1 beta (IL-1β) and IL-6 by activated CD4+ cells obtained from aggressive periodontitis (AgP) patients in comparison with healthy subjects (HC).

MATERIALS AND METHODS

CD4+ cells were automatically separated from lymphocytes obtained from peripheral blood of patients with AgP and healthy controls. Cells were activated for 4, 8, and 24 h with three different stimuli: anti-CD3/anti-CD28, phytohemagglutinin (PHA), and Porphyromonas gingivalis (P. gingivalis) outer membrane protein (OMP). Protein levels were measured in supernatants of activated CD4+ cells by a bead-based immunoassay (CBA). In addition, serum antibodies against P. gingivalis were determined. Data were analyzed using U test (p < 0.05).

RESULTS

T helper cells of AgP patients activated with P. gingivalis OMP produced higher levels of IL-1β and IL-6 in comparison with healthy controls (p < 0.05). Neither the activation with anti-CD3/anti-CD28 nor the activation with PHA showed significantly different production of IL-1β and IL-6 by the cells 25 % of patients and 17 % of controls presented with high serum reactivity to P. gingivalis.

CONCLUSION

In view of these results, it is possible to conclude that P. gingivalis contributes to the pathogenesis of AgP by inducing high levels of pro-inflammatory cytokines such as IL-1β and IL-6 by peripheral CD4+ T helper cells.

CLINICAL RELEVANCE

In accordance with the clinical parameters and the immunological data, we suggest that full-mouth disinfection with adjunctive systemic antibiotics might be the anti-infectious non-surgical periodontal treatment of choice in this type of patients. Microbiological analyses at the beginning and at the end of the periodontal treatment are recommended. However, it is necessary to verify these data in longitudinal clinical studies.

Changes in periodontium after extraction of a periodontally-involved tooth in rats

Purpose

Recent interest has focused on intentional replantation to restore an original tooth. Some studies have shown successful results with intentional replantation for periodontally involved teeth. For long-term success of replantation, a healthy periodontal status of the recipient site is required so that delayed replantation is more suitable for periodontally involved teeth. To reveal the ideal timing for delayed replantation of periodontally involved teeth, the healing process of extraction sockets after extraction of periodontitis-induced teeth in rats was evaluated.

Methods

Twenty-eight rats were randomly divided into two groups: a control group (n=8) and test group (n=20). In the test group, periodontitis was induced by a ligature around the cervix of the mandibular first molar of all of the rats. Two weeks later, the mandibular first molars were extracted in all of the animals. The animals were sacrificed on days 0, 3, 7, and 10 after extraction and histological and immunohistochemical analysis was performed.

Results

In histological analysis of the test group, inflammatory cell infiltrate was found abundantly in the remaining periodontium 3 days after tooth extraction and decreased gradually at later time points. In immunohistochemical analysis of the test group, both interleukin-6 (IL-6) and, tumor necrosis factor-α (TNF-α) were numerous in the furcation area at each postextraction day. IL-6 was stained more heavily between 3 and 7 days after extraction; at day 10 after extraction, little staining was observed. TNF-α staining was more intense at 3 days after extraction and gradually weakened at later points in time.

Conclusions

Within the limits of this study, it takes at least 10 days to resolve periodontal inflammation in rat extraction sockets.