Effect of initial periodontal therapy on gingival crevicular fluid cytokine profile in subjects with chronic periodontitis

Salivary and serum inflammatory biomarkers during periodontitis progression and after treatment

AIM

To identify serum- and salivary-derived inflammatory biomarkers of periodontitis progression and determine their response to non-surgical treatment.

MATERIALS AND METHODS

Periodontally healthy (H; n = 113) and periodontitis patients (P; n = 302) were monitored bi-monthly for 1 year without therapy. Periodontitis patients were re-examined 6 months after non-surgical periodontal therapy (NSPT). Participants were classified according to disease progression: P0 (no sites progressed; P1: 1-2 sites progressed; P2: 3 or more sites progressed). Ten salivary and five serum biomarkers were measured using Luminex. Log-transformed levels were compared over time according to baseline diagnosis, progression trajectory and after NSPT. Significant differences were sought using linear mixed models.

RESULTS

P2 presented higher levels (p < .05) of salivary IFNγ, IL-6, VEGF, IL-1β, MMP-8, IL-10 and OPG over time. Serum analytes were not associated with progression. NSPT led to clinical improvement and significant reduction of IFNγ, IL-6, IL-8, IL-1β, MMP-8, IL-10, OPG and MMP-9 in saliva and of CRP, MMP-8, MMP-9 and MPO in serum.

CONCLUSIONS

Periodontitis progression results from a sustained pro-inflammatory milieu that is reflected in salivary biomarkers, but less so in serum, likely because of the limited amount of progression per patient. NSPT can significantly decrease the levels of several salivary analytes.

Molecular profiling of gingival crevicular fluid fails to distinguish between infrabony and suprabony periodontal defects

AIM

To assess the differential molecular profiling of gingival crevicular fluid (GCF) from infrabony and suprabony periodontal defects compared with healthy sites.

MATERIALS AND METHODS

Seventy-five samples from 25 patients with untreated periodontitis stage III-IV were included. Clinical and radiological parameters as well as GCF samples were collected from an infrabony defect, a suprabony defect and a periodontally healthy site per patient. A multiplex bead immunoassay was performed to assess the level of 18 biomarkers associated with inflammation, connective tissue degradation and regeneration/repair.

RESULTS

GCF volume was higher in periodontal sites compared with healthy sites, with no significant difference between infrabony and suprabony defects. Fourteen biomarkers were elevated in infrabony and suprabony sites compared with healthy sites (p < .05). Only interleukin-1α levels were increased in infrabony compared with suprabony sites, whereas there was no difference in probing pocket depth.

CONCLUSIONS

Although the GCF molecular profile clearly differentiates periodontally affected sites from healthy sites, the different architecture between infrabony and suprabony defects is not reflected in GCF biomarker changes.

Associations between Periodontitis and COPD: An Artificial Intelligence-Based Analysis of NHANES III

A number of cross-sectional epidemiological studies suggest that poor oral health is associated with respiratory diseases. However, the number of cases within the studies was limited, and the studies had different measurement conditions. By analyzing data from the National Health and Nutrition Examination Survey III (NHANES III), this study aimed to investigate possible associations between chronic obstructive pulmonary disease (COPD) and periodontitis in the general population. COPD was diagnosed in cases where FEV (1)/FVC ratio was below 70% (non-COPD versus COPD; binary classification task). We used unsupervised learning utilizing k-means clustering to identify clusters in the data. COPD classes were predicted with logistic regression, a random forest classifier, a stochastic gradient descent (SGD) classifier, k-nearest neighbors, a decision tree classifier, Gaussian naive Bayes (GaussianNB), support vector machines (SVM), a custom-made convolutional neural network (CNN), a multilayer perceptron artificial neural network (MLP), and a radial basis function neural network (RBNN) in Python. We calculated the accuracy of the prediction and the area under the curve (AUC). The most important predictors were determined using feature importance analysis. Results: Overall, 15,868 participants and 19 feature variables were included. Based on k-means clustering, the data were separated into two clusters that identified two risk characteristic groups of patients. The algorithms reached AUCs between 0.608 (DTC) and 0.953% (CNN) for the classification of COPD classes. Feature importance analysis of deep learning algorithms indicated that age and mean attachment loss were the most important features in predicting COPD. Conclusions: Data analysis of a large population showed that machine learning and deep learning algorithms could predict COPD cases based on demographics and oral health feature variables. This study indicates that periodontitis might be an important predictor of COPD. Further prospective studies examining the association between periodontitis and COPD are warranted to validate the present results.

Effect of the Mediterranean diet on gingivitis: A randomized controlled trial

AIM

This study aimed to investigate the effects of a 6-week Mediterranean diet (MD) intervention on gingival inflammatory and anthropometric parameters of patients with gingivitis.

MATERIALS AND METHODS

Forty-two participants were allocated to MD group (MDG) or control group (CG). After a 2-week equilibration period regarding dental care procedures, only MDG changed their diet to MD for 6 weeks, supported by a diet counselling. Gingival and anthropometric parameters were assessed at baseline (T0), Week 2 (T1, beginning of MD intervention), and Week 8 (T2). Adherence to MD was assessed by the Mediterranean Diet Adherence Screener (MEDAS); dietary behaviour was evaluated by the German Health Interview and Examination Survey for Adults Food Frequency Questionnaire (DEGS-FFQ).

RESULTS

Plaque values remained constant in both groups. Inflammatory periodontal and anthropometric parameters decreased in the MDG only (gingival index: T1 1.51 ± 0.21, T2 1.49 ± 0.24; bleeding on probing: T1 51.00 ± 14.65, T2 39.93 ± 13.74; body weight: T1 79.01 ± 15.62, T2 77.29 ± 17.00; waist circumference: T1 84.41 ± 10.1, T2 83.17 ± 10.47 (p < .05). MEDAS revealed a sufficient diet adherence for MDG.

CONCLUSION

Within this study, gingival inflammatory parameters were significantly reduced by MD, whereas plaque parameters remained constant. The diet counselling achieved sufficient adherence with beneficial changes in weight loss and waist circumference.

Molecular profiling of intrabony defects' gingival crevicular fluid

AIM

To profile, for the first time, the gingival crevicular fluid (GCF) of intrabony defects against a wide array of inflammatory and regenerative markers.

MATERIALS AND METHODS

Twenty-one patients contributed one intrabony defect and one periodontally healthy site. Clinical and radiographic measures were obtained. GCF samples were analyzed with multiplex bead immunoassays over 27 markers previously identified by our group. Comparisons were performed using Wilcoxon matched-pairs signed-ranks tests, using a Bonferroni corrected α = 0.05/27 = 0.0019.

RESULTS

Intrabony defect sites presented significantly increased GCF volume and disease-associated clinical and radiographic characteristics (p < .05). Intrabony defect sites presented significantly increased IL-1α, IL-1β, IL-6, IFN-γ, and MMP-8 levels compared with periodontally healthy sites (p < .0019). For regeneration markers, significantly higher FGF basic and VEGF levels were observed (p < .0019). Notably, traits of cell senescence were identified for the first time in the GCF.

CONCLUSIONS

The differentiation of intrabony defects from periodontally healthy control sites can be based on clinical and radiographic measures and on a differentiated GCF profile that is site-specific. Alongside catabolic processes, through significant up-regulation of inflammation and connective tissue remodeling, unique molecular characteristics of intrabony defects may render them a microenvironment amenable to regeneration. Traits of the senescence-associated secretory phenotype may suggest the existence of senescent cells during periodontal inflammation in intrabony defects.

Effects of type 2 diabetes and metformin on salivary microbiota in patients with chronic periodontitis

Diabetes is closely associated with periodontitis, however, the effects of type 2 diabetes and metformin treatment on the salivary microbiota in chronic periodontitis patients are still insufficiently studied. Saliva was collected from ten patients with moderate to severe chronic periodontitis (CP group) and 20 patients with type 2 diabetes mellitus (T2DM) and moderate to severe chronic periodontitis (ten patients were newly diagnosed with diabetes without drug treatment (DM group), and ten patients were treated with metformin (CP-DM-MET group)). Total DNA was extracted. DNA amplicons of the V3-V4 hypervariable regions of the 16S rRNA gene were generated and subjected to high-throughput sequencing. There was no significant difference in the alpha diversity of the salivary microbiota (Observed_Species, Shannon, Simpson, ACE, Chao1 index) among the three groups. The dominant phyla with relative abundances greater than 1% were Firmicutes, Proteobacteria, Bacteroidota, Actinobacteriota, Fusobacteriota, and Spirochaetota, and no significant difference was found among the three groups. Compared with the CP group, the relative abundance of twelve genera was found changed in CP-DM group, for example, Aggregatibacter, Unclassified_f_Neisseriaceae, Parvimonas, Erysipelotrichace_UCG-006, Atopobium, and Endomicrobium et al. Metformin treatment could partly restore the abundance of several genera in CP-DM, such as Acholeplasma and Comamonas. Compared with the CP group, genus Lactobacillus, Parvimonas, Norank_f_norank_o_Absconditabacteriales_SR1, and Acholeplasma changed significantly in CP-DM-MET group. Plaque index (PLI) was positively correlated with Prevotella and Lactobacillus but negatively correlated with Haemophilus, Lautropia, Unclassified_f_Pasteurellaceae, and TM7x. In conclusion, there was a significant difference in the salivary microbiota of patients with chronic periodontitis complicated by T2DM. Treatment with metformin partially alleviated the alteration in salivary microbiota caused by T2DM.

Oral health of patients suffering from end-stage solid organ insufficiency prior to solid organ re-transplantation: a retrospective case series study

Background

The oral health of organ transplanted patients before organ re-transplantation is largely unknown. This retrospective clinical study evaluates the necessity for intraoral surgical intervention and/or conservative treatment in candidates awaiting organ re-transplantation, both for graft failure and for reasons of another upcoming solid organ transplantation (renal or non-renal).

Methods

From January 2015 to March 2020 n = 19 transplant recipients in evaluation on the waiting list for solid organ re-transplantation could be included in the retrospective case series study. Using clinical and radiological examinations, necessity for oral surgical or conservative dental treatment was evaluated. On the basis of anamnesis data, current kidney function, renal replacement treatment (RRT), and medication, a risk profile for several patient subgroups was created.

Results

The clinical and radiological examinations showed a conservative and/or surgical treatment need in n = 13 cases (68.42%). In n = 7 cases (36.84%) surgical intervention was recommended due to residual root remnants (n = 5), unclear mucosal changes (n = 1), and periimplantitis (n = 1). In n = 16 recipients (84.2%) RRT (n = 15 hemodialysis; n = 1 peritoneal dialysis) had been performed. N = 14 recipients (73.68%) received immunosuppressants. In n = 1 patient (5.3%) displayed intraoral and n = 4 patients (21.1%) extraoral neoplasms due to drug-induced immunosuppression.

Conclusions

Solid organ transplant recipients with renal failure present a complex treatment profile due to a double burden of uremia plus immunosuppressants. In cases of surgical treatment need a hospitalized setting is recommended, where potentially necessary follow-up care and close cooperation with disciplines of internal medicine is possible in order to avoid surgical and/or internal complications.

Tobacco Use and Periodontal Disease-The Role of Microvascular Dysfunction

Periodontal disease consists in highly prevalent wide-ranging inflammatory conditions that affect the supporting apparatus of teeth. Tobacco use is the most important risk factor for periodontal disease as it increases disease severity and periodontal surgery complications. Tobacco use is harmful for the vasculature by causing microvascular dysfunction, which is known to negatively affect periodontal disease. To the author's knowledge this paper is the first comprehensive review on the mechanisms by which tobacco use affects oral microcirculation and impacts the pathophysiology of periodontal disease. In healthy subjects, acute nicotine administration or tobacco use (smoking/smokeless forms) increases the blood flow in the oral mucosa due to local irritation and increased blood pressure, which overcome neural- and endocrine-mediated vasoconstriction. Chronic tobacco smokers display an increased gingival microvascular density, which is attributed to an increased capillary recruitment, however, these microcirculatory units show higher tortuosity and lower caliber. These morphological changes, together with the repetitive vasoconstrictive insults, contribute to lower gingival perfusion in chronic smokers and do not completely regress upon smoking cessation. In periodontal disease there is considerable gingival inflammation and angiogenesis in non-smokers which, in chronic smokers, are considerably suppressed, in part due to local immune suppression and oxidative stress. Tobacco exposure, irrespective of the form of use, causes long-term microvascular dysfunction that increases the risk of complications due to the natural disease course or secondary therapeutic strategies.

Oral Dysbiosis and Inflammation in Parkinson's Disease

Background:

Oral microbiota has largely escaped attention in Parkinson’s disease (PD), despite its pivotal role in maintaining oral and systemic health.

Objective:

The aim of our study was to examine the composition of the oral microbiota and the degree of oral inflammation in PD.

Methods:

Twenty PD patients were compared to 20 healthy controls. Neurological, periodontal and dental examinations were performed as well as dental scaling and gingival crevicular fluid sampling for cytokines measurement (interleukine (IL)-1β, IL-6, IL-1 receptor antagonist (RA), interferon-γ and tumor necrosis factor (TNF)-α). Two months later, oral microbiota was sampled from saliva and subgingival dental plaque. A 16S rRNA gene amplicon sequencing was used to assess bacterial communities.

Results:

PD patients were in the early and mid-stage phases of their disease (Hoehn & Yahr 2–2.5). Dental and periodontal parameters did not differ between groups. The levels of IL-1β and IL-1RA were significantly increased in patients compared to controls with a trend for an increased level of TNF-α in patients. Both saliva and subgingival dental plaque microbiota differed between patients and controls. Streptococcus mutans, Kingella oralis, Actinomyces AFQC_s, Veillonella AFUJ_s, Scardovia, Lactobacillaceae, Negativicutes and Firmicutes were more abundant in patients, whereas Treponema KE332528_s, Lachnospiraceae AM420052_s, and phylum SR1 were less abundant.

Conclusion:

Our findings show that the oral microbiome is altered in early and mid-stage PD. Although PD patients had good dental and periodontal status, local inflammation was already present in the oral cavity. The relationship between oral dysbiosis, inflammation and the pathogenesis of PD requires further study.

Vascular Endothelial Growth Factor: A Translational View in Oral Non-Communicable Diseases

Vascular endothelial growth factors (VEGFs) are vital regulators of angiogenesis that are expressed in response to soluble mediators, such as cytokines and growth factors. Their physiologic functions include blood vessel formation, regulation of vascular permeability, stem cell and monocyte/macrophage recruitment and maintenance of bone homeostasis and repair. In addition, angiogenesis plays a pivotal role in chronic pathologic conditions, such as tumorigenesis, inflammatory immune diseases and bone loss. According to their prevalence, morbidity and mortality, inflammatory diseases affecting periodontal tissues and oral cancer are relevant non-communicable diseases. Whereas oral squamous cell carcinoma (OSCC) is considered one of the most common cancers worldwide, destructive inflammatory periodontal diseases, on the other hand, are amongst the most prevalent chronic inflammatory conditions affecting humans and also represent the main cause of tooth loss in adults. In the recent years, while knowledge regarding the role of VEGF signaling in common oral diseases is expanding, new potential translational applications emerge. In the present narrative review we aim to explore the role of VEGF signaling in oral cancer and destructive periodontal inflammatory diseases, with emphasis in its translational applications as potential biomarkers and therapeutic targets.

Gingival crevicular fluid biomarkers in type 1 diabetes mellitus: A case-control study

OBJECTIVE

The aim of the study is to compare the levels of Gingival Crevicular Fluid (GCF) interleukin 8 (IL-8), matrix metalloproteinase 8 (MMP-8) and advanced glycated-end products (AGEs) in a cohort of type 1 diabetic (T1D) subjects and healthy controls.

MATERIAL AND METHODS

GCF samples and periodontal examination were assessed in 50 subjects with T1D (30 males and 20 females; mean age: 35.2 years) recruited from the Diabetology Unit of the Geneva University Hospitals and in 50 control subjects matched for gender, age and smoking status. Samples were assessed for IL-8 and MMP-8 using a bead array multianalyte detection system and for AGEs the ELISA. The two groups were compared using the Wilcoxon signed rank test.

RESULTS

The mean HbA1c differed significantly between the groups (8.3% for the T1D group vs. 5.2% for the control group, p < 0.001). T1D subjects had significantly more plaque and gingival inflammation and presented more sites with bleeding on probing compared to the controls. The GCF levels of IL-8, MMP-8 and AGEs did not differ significantly between the groups. Further analysis of the GCF markers in younger (<40 years) and older (≥40 years) cohorts, revealed no significant differences between younger diabetics and controls or between older diabetics and controls. When the groups were divided according to their glycemic status (HbA1c 6.1-8, and > 8%), again no significant differences could be identified for any of the biochemical markers.

CONCLUSIONS

T1D subjects, particularly the younger ones, exhibited more inflammation compared to the matched healthy controls. Results on the GCF expression of IL-8, MMP-8 and AGEs did not differ between the groups. The diabetic population of our cohort was for the most part fairly-controlled, with little if any complications and with presence of only mild type of periodontal disease, as 68% had gingivitis.

CXCL5, CXCL8, and CXCL10 regulation by bacteria and mechanical forces in periodontium

OBJECTIVE

The aim of the present study was to evaluate the expressions of CXCL5, CXCL8, and CXCL10 in periodontal cells and tissues in response to microbial signals and/or biomechanical forces.

METHODS

Human gingival biopsies from inflamed and healthy sites were used to examine the chemokine expressions and protein levels by real-time PCR and immunohistochemistry. The chemokines were also investigated in gingival biopsies from rats submitted to experimental periodontitis and/or tooth movement. Furthermore, chemokine levels were determined in human periodontal fibroblasts stimulated by the periodontopathogen Fusobacterium nucleatum and/or constant tensile forces (CTS) by real-time PCR and ELISA. Additionally, gene expressions were evaluated in periodontal fibroblasts exposed to F. nucleatum and/or CTS in the presence and absence of a MAPK inhibitor by real-time PCR.

RESULTS

Increased CXCL5, CXCL8, and CXCL10 levels were observed in human and rat gingiva from sites of inflammation as compared with periodontal health. The rat experimental periodontitis caused a significant (p<0.05) increase in alveolar bone resorption, which was further enhanced when combined with tooth movement. In vitro, F. nucleatum caused a significant upregulation of CXCL5, CXCL8, and CXCL10 at 1 day. Once the cells were exposed simultaneously to F. nucleatum and CTS, the chemokines regulation was significantly enhanced. The transcriptional findings were also observed at protein level. Pre-incubation with the MEK1/2 inhibitor significantly (p<0.05) inhibited the stimulatory actions of F. nucleatum either alone or in combination with CTS on the expression levels of CXCL5, CXCL8, and CXCL10 at 1d.

CONCLUSIONS

Our data provide original evidence that biomechanical strain further increases the stimulatory actions of periodontal bacteria on the expressions of these chemokines. Therefore, biomechanical loading in combination with periodontal infection may lead to stronger recruitment of immunoinflammatory cells to the periodontium, which might result in an aggravation of periodontal inflammation and destruction.

Gingival Crevicular Fluid Cytokines in Moderate and Deep Sites of Stage III Periodontitis Patients in Different Rates of Clinical Progression

Clinical criteria are inappropriate to measure the degree of susceptibility to progression of periodontal damage. Thus, the aim of this study was to assess whether gingival crevicular fluid (GCF) levels of cytokines could discriminate patients suffering from stage III periodontitis with moderate (Grade B) and rapid rates of progression (Grade C) prior to and 6 months after non-surgical periodontal treatment. GCF samples were obtained from moderate and deep sites of 20 patients diagnosed as Grade B and 20 patients as grade C stage III periodontitis and analyzed for interleukin (IL)-1β, IL-9, tumor necrosis factor (TNF)-α, and vascular endothelial growth factor (VEGF) using a high-sensitivity Bio-Plex Suspension Array System. At baseline, higher IL-1β but lower IL-9 GCF levels were observed in moderate sites of the grade C compared to the grade B group. In spite of comparable clinical improvement, this difference maintained after treatment, suggesting a residual pro-inflammatory state. In deep sites, no differences were observed between periodontitis groups except for VEGF levels that decreased more in Grade B periodontitis at 6 months post-therapy. A mathematical model was constructed to identify Grade C periodontitis patients based on the subjects’ GCF levels of IL-1β and IL-9, which achieved an area under the receiver-operating characteristic (ROC) curve of 0.94. This study can contribute to the early assessment of risk of future breakdown in periodontitis patients.

Adjunctive Antiseptic Irrigation of Periodontal Pockets: Effects on Microbial and Cytokine Profiles

To evaluate the effect of adjunctive antiseptic irrigation of periodontal pockets on microbial and cytokine profiles. Fifty-nine patients with severe periodontitis were allocated to one of three groups for scaling and root planing facilitated with different adjunctive antiseptics: 1% polyhexamethyleneguanidine phosphate (PHMG-P) (n = 19), 0.2% chlorhexidine (CHX) (n = 21) or distilled water (n = 19). Gingival crevicular fluid and subgingival bacterial samples were collected at baseline, and at 2 weeks, and 1 and 4 months. The levels of interleukin (IL)-1β, IL-8, IL-10, and IL-17A, matrix metalloproteinase (MMP)-8, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum,Aggregatibacter actinomycetemcomitans, and Prevotella intermedia were determined. There were no intergroup differences in cytokine concentrations and bacterial counts at any follow-up, however, varying patterns were observed. In the PHMG-P and water groups IL-1β expression peaked at 2 weeks and then gradually declined. In all three groups, the dynamics of MMP-8 concentration were non-linear, increasing by 2 weeks and then declining to below baseline (p > 0.05). P. gingivalis and T. forsythia declined within the first month and increased thereafter, not regaining the baseline level. Adjunctive antiseptic treatment was associated with changes in biomarkers and bacterial counts in the course of the study. The effects of adjunctive antiseptic irrigation were limited in the applied protocol.

Cytokine profiles of healthy and diseased sites in individuals with periodontitis

OBJECTIVE

The aims of this study were: 1) to compare the levels of cytokines between healthy and diseased sites, in patients with untreated periodontitis; 2) to correlate cytokine levels with each other and with key periodontal pathogens, in healthy and diseased sites.

METHODS

Paired gingival crevicular fluid (GCF) samples were obtained from two healthy (probing depth (PD) and clinical attachment level (CAL) ≤3 mm without bleeding) and two diseased sites (PD and CAL ≥5 mm with bleeding on probing [BoP]) of patients with generalized stage III/IV grade B/C periodontitis. GCF levels of eighteen cytokines and subgingival levels of seven periodontal pathogens were assessed by multiplex immunoassay and qPCR, respectively.

RESULTS

A total of 112 subjects and 448 GCF samples were analyzed. The GCF levels of GM-CSF, IL-17, IL-1β, IL-2, IL-21, IL-23 and TGF-β were significantly higher in the diseased than in the healthy sites (p < 0.05). Levels of IL-8 and MIP-1α were significantly higher in the healthy than in the diseased sites (p < 0.05). In the healthy sites, IL-8 and MIP-1α formed an independent cluster of cytokines and, MIP-1α positively correlated with Porphyromonas gingivalis (p < 0.05). In deep sites, smoking negatively associated with GM-CSF, IL-10, IL-17, IL-23, IL-5, IL-6, IL-7, IL-8 and MIP-1α levels (p < 0.05).

CONCLUSIONS

Diseased sites exhibited increased levels of T helper 17-related cytokines and TGF-β while healthy sites presented increased levels of the chemokines, IL-8 and MIP-1α. Patients with periodontitis may not only have inflammation in diseased deep sites, but also present significant hidden subclinical inflammation in their shallow clinically healthy sites.

Salivary and serum markers of angiogenesis in periodontitis in relation to smoking

OBJECTIVE

Angiogenesis is essential in maintenance of periodontal homeostasis, and it is regulated by growth factors and cytokines, including basic fibroblast growth factor (b-FGF), endoglin, platelet and endothelial cell adhesion molecule (PECAM-1), vascular endothelial growth factor (VEGF), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1). In this study, the salivary and serum concentrations of these angiogenesis-related proteins in relation to smoking and periodontitis were examined.

MATERIAL AND METHODS

Full-mouth periodontal status together with unstimulated whole saliva and serum samples was collected from 78 individuals, including 40 periodontitis patients (20 smokers and 20 nonsmokers) and 38 periodontally healthy controls (20 smokers and 18 nonsmokers). The Luminex®-xMAP™ technique was used for protein analyses.

RESULTS

Concentrations of all tested proteins in saliva as well as VEGF in serum were significantly higher in periodontitis patients than in healthy controls. In smokers, serum concentrations of endoglin (p = 0.017) and sICAM-1 (p = 0.001) were elevated in comparison to nonsmokers. After adjusting for smoking and gender, periodontitis associated significantly with salivary concentrations of b-FGF, PECAM-1, VEGF, sICAM-1, and sVCAM-1 (p < 0.01).

CONCLUSION

Taken together, salivary concentrations of b-FGF, PECAM-1, and VEGF associate with periodontitis. The suppressive effect of smoking on salivary marker levels is limited to periodontitis patients only.

CLINICAL RELEVANCE

Smoking-related suppression of salivary marker levels is observed only in periodontitis patients.

Oral Microbiome Signatures in Diabetes Mellitus and Periodontal Disease

Disturbances in the oral microbiome are associated with periodontal disease initiation and progression and diabetes mellitus (DM), but how this contributes to the cause-and-effect relationship between periodontal disease and DM is poorly understood. We examined the bacterial composition in plaque samples from 128 South Africans with periodontal disease across glycemic statuses using 16S rDNA sequencing of regions 2, 3, 4, 6-7, 8, and 9. Of the 9 phyla identified, Firmicutes, Proteobacteria, Bacteroidetes, Fusobacteria, and Actinobacteria made up >98%. Fusobacteria and Actinobacteria were significantly more abundant in subjects with diabetes, while Proteobacteria were less abundant. However, in the presence of gingival bleeding and DM, as compared with DM without gingival bleeding, Actinobacteria were markedly reduced while Bacteroidetes were more abundant. In contrast, no differences in Actinobacteria or Bacteroidetes abundance were observed between DM with and without pocket depth (PD) ≥4 mm. At the genus level, similar changes in relative abundance were observed in the presence of DM and periodontal disease. Our findings remained in conditional logistic regression models adjusted for age, sex, waist circumference, and the 5 most dominant phyla. For example, Actinobacteria significantly increased the odds of diabetes by 10% in subjects with gingival bleeding, while Fusobacteria increased this odd by 14%; yet, among subjects with PD ≥4 mm, Fusobacteria decreased the odds of DM by 47%. Our findings have confirmed the alterations in the composition of the oral microbiota across glycemic statuses as well as different stages of periodontal disease. However, it is not clear whether these differences were the consequence of hyperglycemia or the presence of periodontal diseases. Therefore, we recommend further investigations in a longitudinal study design.

Immunohistochemical, histomorphometric, and gingival crevicular fluid analysis of residual and shallow periodontal pockets in patients with periodontitis Stages III and IV

BACKGROUND

To study the differences between shallow and residual periodontal pockets in patients with periodontitis (Stages III and IV) after non-surgical periodontal treatment.

METHODS

Twenty patients diagnosed of periodontitis who were scheduled for periodontal surgery were included. In each patient, a palatal shallow site (≤3 mm) and a residual site (≥5 mm) were selected and GCF samples were processed by Luminex® analysis to determine the concentrations of interleukins (IL-1β, IL-6, IL-10, and IL-17a). During the periodontal surgery gingival biopsies were collected and processed for histo-morphometric and immunohistochemical evaluation to determine the extent of connective tissue inflammatory infiltrate (CTII) using the following markers (CD4, CD5, CD8, CD14, CD19, Elastase, and Syndecan). Mean differences between shallow and residual pockets samples, as well as correlations between GCF cytokine concentrations, area of CTII, and cellularity of the CTII were calculated.

RESULTS

A total of 15 patients were finally included, with analysis of 30 histological specimens and 30 GCF samples. Residual pockets presented significantly higher mean GCF volume, higher mean area of CTII and higher concentrations of IL-1β and IL-6 in GCF than shallow pockets. A significant correlation was detected between IL-10 levels and the CTII area, IL-10 and the percentage of Syndecan, and the area of CTII and the percentages of CD14 and Syndecan.

CONCLUSIONS

The concentration of GCF cytokines did not correlate with the area of CTII measured histologically. A residual CTII and elevated concentrations of proinflammatory cytokines and cells were present in all sites 2 months after non-surgical treatment. The lack of healthy controls does not allow to establish differences between both groups.

Developing a periodontal disease antibody array for the prediction of severe periodontal disease using machine learning classifiers

BACKGROUND

The aim of this study was to simultaneously and quantitatively assess the expression levels of 20 periodontal disease-related proteins in gingival crevicular fluid (GCF) from normal controls (NOR) and severe periodontitis (SP) patients with an antibody array.

METHODS

Antibodies against 20 periodontal disease-related proteins were spotted onto a glass slide to create a periodontal disease antibody array (PDD). The array was then incubated with GCF samples collected from 25 NOR and 25 SP patients. Differentially expressed proteins between NOR and SP patients were then used to build receiver operator characteristic (ROC) curves and compare five classification models, including support vector machine, random forest, k nearest neighbor, linear discriminant analysis, and Classification and Regression Trees.

RESULTS

Seven proteins (C-reactive protein, interleukin [IL]-1α, interleukin-1β, interleukin-8, matrix metalloproteinase-13, osteoprotegerin, and osteoactivin) were significantly upregulated in SP patients compared with NOR, while receptor activator of nuclear factor-kappa was significantly downregulated. The highest diagnostic accuracy using a ROC curve was observed for IL-1β with an area under the curve of 0.984. Five of the proteins (IL-1β, IL-8, MMP-13, osteoprotegerin, and osteoactivin) were identified as important features for classification. Linear discriminant analysis had the highest classification accuracy across the five classification models that were tested.

CONCLUSION

This study highlights the potential of antibody arrays to diagnose periodontal disease.

H2S mediates increased interleukin (IL)-1β and IL-18 production in leukocytes from patients with periodontitis

Background: The mechanisms involved in the interplay between the bacteria and the host cells in periodontitis are not fully understood.

Aim: To investigate the effect of the bacterial metabolite H₂S on the pro-inflammatory cytokines interleukin (IL)-1β and IL-18 from periodontitis patients and healthy controls, and to evaluate the composition of the subgingival microbiota with its capacity to produce H₂S.

Methods: Subgingival bacterial samples from patients with periodontitis (N=32) and healthy controls (N=32) were investigated for H₂S production and bacterial composition. Peripheral blood mononuclear cells (PBMCs) were cultured in the presence/absence of 1mM H₂S for 24h and cytokine concentrations were measured.

Results: Subgingival plaque from periodontitis patients had more H₂S producing bacteria and produced more H₂S, than healthy controls. PBMCs exposed to H₂S secreted significantly more IL-1ß and IL-18 (p<0.0001) than untreated control PBMCs from both groups. PBMCs from the periodontitis patients secreted higher levels of the cytokines, both spontaneously (IL-1ß p=0.0001; IL-18 p=0.09) and after exposure to H₂S (IL-1ß p=0.03; IL-18 p=0.04), which is a new finding not previously reported.

Conclusions: H₂S, from the subgingival microbiota, can contribute to a host inflammatory response through secretion of the pro-inflammatory cytokines IL-1β and IL-18. Since this response differs between individuals, it may also reflect the susceptibility of the host to develop periodontitis.

Systemic inflammatory burden and local inflammation in periodontitis: What is the link between inflammatory biomarkers in serum and gingival crevicular fluid?

In periodontitis patients, high levels of several inflammatory markers may be expressed in serum, reflecting the effect of local disease on the general health. The objective of the present analysis was to compare cytokine levels assessed in peripheral blood with those in the gingival crevicular fluid (GCF) and evaluate the impact of nonsurgical periodontal therapy on the incidence of high levels of 12 biomarkers in serum. Twenty-four patients with chronic periodontitis (Group P) contributed with serum and GCF samples at baseline (BL) and 1 and 3 months after periodontal treatment (M1 and M3). Samples were assessed for 12 cytokines using the Bio-Plex bead array multianalyte detection system. For each analyte, peak values were calculated as greater than the mean + 2SD of the one found in 60 periodontally healthy participants. Significant correlations between serum and GCF values were obtained in the periodontitis group for interleukin (IL) 1ra, IL-6, and interferon γ at BL and for macrophage inflammatory protein 1β at M3 after treatment. Periodontitis subjects were found to exhibit high peaks for several inflammatory markers in serum. The highest incidence of peaks at BL was found for interferon γ (37.5% of the periodontitis subjects). For the four biomarkers with a detection frequency of >75% at BL (IL-1ra, IL-8, macrophage inflammatory protein 1β, and vascular endothelial growth factor), no significant difference was observed over time for the P group or between the two groups at BL. The significant correlation found between the serum and the GCF for certain cytokines and the fact that periodontitis subjects exhibit high peaks for several inflammatory markers in serum may support the hypothesis that the inflammatory reaction due to periodontitis is not restricted to the diseased sites. Within the limitations of the study, periodontal therapy did not seem to have any significant impact on the systemic cytokine levels.

Understanding the pathophysiology behind chairside diagnostics and genetic testing for IL-1 and IL-6

In order for chairside diagnostic testing to make an impact on dental therapy, practitioners require a better understanding of genetic mutations contributing to the pathophysiology of periodontal disease. Commensal and pathogenic bacterial colonization in oral cavity tissues produces a cascade of proinflammatory signaling pathways ultimately detrimental to host tissues. Resolving inflammation is a multifactorial process involving the downregulation of proinflammatory cytokines while allowing commensal bacterial levels to return to normal. Because of the complicated nature of commensal bacteria and oral health homeostasis, the emphasis of dental therapy should place renewed focus on limiting destructive inflammation rather than solely eliminating bacteria. Salivary diagnostics are an easy, non-invasive way to assess inflammatory markers. Inflammatory cytokine levels can help determine the subclinical health of a patient, showing the transition from health to gingivitis, or periodontitis, prior to clinical presentation. Single nucleotide polymorphism mutations can aid in determining increased risk of developing periodontitis. Taken together, and alongside regular clinical evaluations, chairside diagnostics help individualize treatment plans to slow, or halt, the progression of disease-before tissue destruction can take place. While more studies are needed analyzing specific mutations across periodontal categories, chairside diagnostics present an exciting adjunct to improve patient care.

GWAS for Interleukin-1β levels in gingival crevicular fluid identifies IL37 variants in periodontal inflammation

There is no agnostic GWAS evidence for the genetic control of IL-1β expression in periodontal disease. Here we report a GWAS for "high" gingival crevicular fluid IL-1β expression among 4910 European-American adults and identify association signals in the IL37 locus. rs3811046 at this locus (p = 3.3 × 10-22) is associated with severe chronic periodontitis (OR = 1.50; 95% CI = 1.12-2.00), 10-year incident tooth loss (≥3 teeth: RR = 1.33; 95% CI = 1.09-1.62) and aggressive periodontitis (OR = 1.12; 95% CI = 1.01-1.26) in an independent sample of 4927 German/Dutch adults. The minor allele at rs3811046 is associated with increased expression of IL-1β in periodontal tissue. In RAW macrophages, PBMCs and transgenic mice, the IL37 variant increases expression of IL-1β and IL-6, inducing more severe periodontal disease, while IL-37 protein production is impaired and shows reduced cleavage by caspase-1. A second variant in the IL37 locus (rs2708943, p = 4.2 × 10-7) associates with attenuated IL37 mRNA expression. Overall, we demonstrate that IL37 variants modulate the inflammatory cascade in periodontal disease.

Effect of initial periodontal therapy on gingival crevicular fluid cytokine profile in subjects with chronic periodontitis

Cytokines are thought to play an important role in the pathogenesis of periodontal disease. Because periodontal disease is known for its inhomogeneous distribution within the dentition, it is unclear to what extent the detection of various cytokines at different sites correlates with presence of disease. We evaluated whether levels of 12 cytokines in gingival crevicular fluid (GCF) discriminated periodontally diseased sites from healthy ones, or periodontally diseased persons from healthy ones, and assessed the impact of nonsurgical periodontal therapy on these readings. This study included 20 periodontally healthy persons (H) and 24 patients with chronic periodontitis (P). In every participant, we measured the plaque index, gingival index, probing pocket depth (PD), bleeding on probing, and recession at six sites of every tooth. GCF was collected with Durapore^® filter strips from two healthy sites (PD<4 mm; HH) in group H, and from two periodontally diseased sites (PD≥5 mm; PP) and two periodontally healthy sites (PD≤3 mm; PH) in group P. The periodontally diseased participants underwent comprehensive nonsurgical periodontal therapy including deep scaling and root planing under local anesthesia. In these participants, GCF samples were again collected at the same sites 1 and 3 months after therapy. Twelve cytokines (il‐1β, il‐1ra, il‐6, il‐8, il‐17, b‐fgf, g‐csf, gm‐csf, ifn‐γ, mip‐1β, vegf, and tnf‐α) were assessed using the Bio‐Plex suspension array system. Mean plaque index, gingival index, bleeding on probing, PD, and recession were significantly different between groups H and P. Differences between PP and PH sites were not significant for any of the cytokines. Il‐1ra, il‐6, il‐17, b‐fgf, gm‐csf, mip‐1β, and tnf‐α differed significantly between HH sites and both PH and PP sites, whereas il‐8 was significantly higher only at PP sites. Periodontal treatment increased gm‐csf and decreased il‐1ra levels in PP sites. Il‐1ra, il‐6, il‐8, il‐17, b‐fgf, gm‐csf, mip‐1β, and tnf‐α identified patients with chronic periodontitis, rather than diseased sites, suggesting a generalized inflammatory state that is not limited to clinically diseased sites only.