Heterogeneity of host immunological risk factors in patients with aggressive periodontitis

Integrated analysis of the salivary microbiome and metabolome in chronic and aggressive periodontitis: A pilot study

This pilot study was designed to identify the salivary microbial community and metabolic characteristics in patients with generalized periodontitis. A total of 36 saliva samples were collected from 13 patients with aggressive periodontitis (AgP), 13 patients with chronic periodontitis (ChP), and 10 subjects with periodontal health (PH). The microbiome was evaluated using 16S rRNA gene high-throughput sequencing, and the metabolome was accessed using gas chromatography-mass spectrometry. The correlation between microbiomes and metabolomics was analyzed by Spearman’s correlation method. Our results revealed that the salivary microbial community and metabolite composition differed significantly between patients with periodontitis and healthy controls. Striking differences were found in the composition of salivary metabolites between AgP and ChP. The genera Treponema, Peptococcus, Catonella, Desulfobulbus, Peptostreptococcaceae_[XI] ([G-2], [G-3] [G-4], [G-6], and [G-9]), Bacteroidetes_[G-5], TM7_[G-5], Dialister, Eikenella, Fretibacterium, and Filifactor were present in higher levels in patients with periodontitis than in the healthy participants. The biochemical pathways that were significantly different between ChP and AgP included pyrimidine metabolism; alanine, aspartate, and glutamate metabolism; beta-alanine metabolism; citrate cycle; and arginine and proline metabolism. The differential metabolites between ChP and AgP groups, such as urea, beta-alanine, 3-aminoisobutyric acid, and thymine, showed the most significant correlations with the genera. These differential microorganisms and metabolites may be used as potential biomarkers to monitor the occurrence and development of periodontitis through the utilization of non-invasive and convenient saliva samples. This study reveals the integration of salivary microbial data and metabolomic data, which provides a foundation to further explore the potential mechanism of periodontitis.

Circulating inflammatory cell profiling and periodontitis: A systematic review and meta-analysis

Inflammation is a key driver of common noncommunicable diseases. Among common triggers of inflammation, chronic gingival inflammation (periodontitis) triggers a consistent humoral host inflammatory response, but little is known on its impact on circulating inflammatory cell profiles. We aimed to systematically appraise all the evidence linking periodontitis and its treatment to circulating inflammatory cell profiles. From 6 databases, 157 studies were eligible for qualitative synthesis and 29 studies for meta-analysis. Our meta-analysis showed that participants with periodontitis exhibited a significant mean increase in circulating CD4⁺ , CD4⁺ CD45RO⁺ , IFNγ-expressing CD4⁺ and CD8⁺ T cells, CD19⁺ CD27⁺ and CD5⁺ B cells, CD14⁺ CD16⁺ monocytes, and CD16⁺ neutrophils but decrease in CD8⁺ T and CD14⁺⁺ CD16^- monocytes. Our qualitative synthesis revealed that peripheral blood neutrophils of patients with periodontitis consistently showed elevated production of reactive oxygen species (ROS) when compared with those of healthy controls. Some evidence suggested that the treatment of periodontitis reversed the exaggerated ROS production, but limited and inconclusive data were found on several circulating inflammatory cell profiling. We conclude that periodontitis and its treatment are associated with minor but consistent alterations in circulating inflammatory cell profiles. These changes could represent key mechanisms explaining the association of periodontitis with other comorbidities such as cardiovascular disease, diabetes, and rheumatoid arthritis.

Comparative Evaluation of Cost-Effectiveness, Clinical and Microbiological Parameters of Systemic Antibiotics Versus Local Drug Delivery in Aggressive Periodontitis

BACKGROUND

Periodontitis is a biofilm-associated inflammatory disease of the periodontium in which microbial component contributes to its initiation that mainly includes chronic periodontitis and aggressive periodontitis (AgP).

AIM

The present study aimed to ascertain a cost-effective treatment approach in AgP with minimal side effects by comparing systemic antibiotics (SA) and local drug delivery (LDD) as an adjunct to scaling and root planning (SRP). Furthermore, the objectives were to analyze its effect on clinical and microbial parameters.

MATERIALS AND METHODS

The participants were randomly divided into two groups A and B with eleven participants each. Group A was administered with Chlosite Gel [LDD] whereas group B with amoxicillin (AMX) 500 mg + metronidazole (MTZ) 400 mg [SA] thrice daily for 14 days. Clinical parameters such as plaque index (PI), gingival index (GI), clinical attachment level (CAL), and pocket probing depth (PPD)] were recorded at baseline and three months postoperatively. Microbiological parameters i.e Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) counts were also measured at baseline and after three months.

RESULTS

Statistically significant difference was observed in all clinical parameters i.e. PI, GI, CAL, and PPD after three months follow-up in groups A and B. Reduced bacterial load i.e. Aa and Pg was significant at three months in both the groups. However, on comparing the total expenditure of both the groups, group A ranged from 920-1480 ₹ while in group B it ranged from 330-360 ₹. Hence, lower expenditure in group B (3.7 fold) compared to group A was evident.

CONCLUSIONS

Cost-effective approach recommended in the present study is mainly to promote awareness among periodontal patients in the public and private sectors, who refuse to get dental treatment due to fear of high expenditure. This can be attained by incorporating SA as an alternative to LDD in AgP patients.

Effect of non-surgical periodontal treatment on gingival crevicular fluid hypoxia inducible factor-1 alpha, vascular endothelial growth factor and tumor necrosis factor-alpha levels in generalized aggressive periodontitis patients

BACKGROUND

Hypoxia-inducible angiogenic pathway involving hypoxia inducible factor-1 alpha (HIF-1α), vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-α) may regulate several biological processes related to inflammation. The present study aimed to assess the effect of non-surgical periodontal treatment on gingival crevicular fluid (GCF) HIF-1α, VEGF, and TNF-α levels in generalized aggressive periodontitis (G-AgP).

METHODS

Twenty G-AgP patients and 20 periodontally healthy individuals were included. G-AgP patients received scaling and root planning (SRP), per quadrant at a 1-week-interval, performed with ultrasonic and periodontal hand instruments. GCF samples were collected and clinical periodontal parameters including probing depth, clinical attachment level, gingival index and plaque index were recorded at baseline, 1 and 3 months after treatment. Biomarker levels in GCF were analyzed by ELISA.

RESULTS

At baseline all clinical parameters and GCF HIF-1α, VEGF, and TNF-α levels were significantly higher in G-AgP patients compared to healthy control (P < 0.05). All clinical parameters improved over the 3-month-period in G-AgP patients (P < 0.05). GCF HIF-1α levels in G-AgP reduced at 1 and 3 months post-treatment, however, this did not reach to statistical significance (P > 0.05). GCF VEGF and TNF-α levels remained unchanged throughout the study period (P > 0.05).

CONCLUSIONS

Within the limitations of the present study, although HIF-1α seems to possess a potential diagnostic value for G-AgP, it might not be a proper predictor of clinically favorable treatment outcome. SRP plus different adjunctive therapies could provide better information about the prognostic role of hypoxia-inducible angiogenic pathway in G-AgP.

Hidden noise in immunologic parameters might explain rapid progression in early-onset periodontitis

To investigate in datasets of immunologic parameters from early-onset and late-onset periodontitis patients (EOP and LOP), the existence of hidden random fluctuations (anomalies or noise), which may be the source for increased frequencies and longer periods of exacerbation, resulting in rapid progression in EOP. Principal component analysis (PCA) was applied on a dataset of 28 immunologic parameters and serum IgG titers against periodontal pathogens derived from 68 EOP and 43 LOP patients. After excluding the PCA parameters that explain the majority of variance in the datasets, i.e. the overall aberrant immune function, the remaining parameters of the residual subspace were analyzed by computing their sample entropy to detect possible anomalies. The performance of entropy anomaly detection was tested by using unsupervised clustering based on a log-likelihood distance yielding parameters with anomalies. An aggregate local outlier factor score (LOF) was used for a supervised classification of EOP and LOP. Entropy values on data for neutrophil chemotaxis, CD4, CD8, CD20 counts and serum IgG titer against Aggregatibacter actinomycetemcomitans indicated the existence of possible anomalies. Unsupervised clustering confirmed that the above parameters are possible sources of anomalies. LOF presented 94% sensitivity and 83% specificity in identifying EOP (87% sensitivity and 83% specificity in 10-fold cross-validation). Any generalization of the result should be performed with caution due to a relatively high false positive rate (17%). Random fluctuations in immunologic parameters from a sample of EOP and LOP patients were detected, suggesting that their existence may cause more frequently periods of disease activity, where the aberrant immune response in EOP patients result in the phenotype "rapid progression".

Comparison of miRNA expression profiles in individuals with chronic or aggressive periodontitis

OBJECTIVES

MicroRNAs (miRNAs) may play an important role in inflammatory response. However, the involvement of miRNAs in the pathogenesis of periodontitis is unclear. The present study aimed to compare the miRNA expression profiles in individuals with chronic (CP) or aggressive (AP) periodontitis.

MATERIALS AND METHODS

Eighteen non-smoker individuals (CP = 9 and AP = 9) without any history of systemic diseases or previous periodontal therapies were selected at the Clinics of Periodontology from the Federal University of Minas Gerais. Gingival tissue samples were collected during the initial periodontal therapy. miRNAs were isolated, and expression patterns of 754 miRNAs were assessed with a quantitative miRNA PCR array. miRNAs expression profiles were compared between CP and AP groups.

RESULTS

There were no differences observed in the miRNAs expression profiles between CP and AP (p > 0.05). According to the microarray analyses, the most expressed miRNAs in both groups were hsa-miR-1274b, hsa-let-7b-5p, hsa-miR-24-3p, hsa-miR-19b-3p, hsa-miR-720, hsa-miR-126-3p, hsa-miR-17-3p and hsa-miR-21-3p.

CONCLUSION

Findings suggested no differences in miRNAs expression profiles between chronic and aggressive forms of periodontitis. The overexpression of specific miRNAs could provide insights into the pathogenesis of both forms of the disease.

Assessment of microRNA-146a in generalized aggressive periodontitis and its association with disease severity

BACKGROUND AND OBJECTIVE

MicroRNA-146a (miR-146a) is a small noncoding RNA that plays a critical role in the negative regulation of the innate immune response, and the dysregulation of miR-146a has been associated with several inflammatory disorders. In generalized aggressive periodontitis (GAgP) the degree of clinical inflammation appears to be similar to that of chronic periodontitis, and, in this situation, age of onset and family history are important additional criteria for diagnosis. This study was performed to evaluate the level of miR-146a expressed in gingival tissues of patients with GAgP and its association with disease severity.

MATERIAL AND METHODS

Gingival samples from 18 patients with GAgP and 10 healthy subjects were collected and the level of miR-146a and its targets, including necrosis factor-alpha, interleukin-1beta, and interleukin-6, were assessed using real-time PCR. Clinical parameters, including probing depth and clinical attachment loss, were measured and their correlations with the level of miR-146a were determined.

RESULTS

Our results demonstrated an elevation in the level of miR-146a expressed in patients with GAgP compared with healthy controls (P < .001), which was directly associated with disease severity (P < .05). Overexpression of miR-146a was accompanied by a reduction in the levels of pro-inflammatory cytokines.

CONCLUSIONS

Our findings suggest that there is an association between miR-146a and GAgP and imply that miR-146a may serve as an indicator of periodontal disease severity. However, further studies and additional information are required to confirm this relationship and the precise role of miR-146a in the development and/or progression of periodontitis.

Orthodontic Management in Aggressive Periodontitis

Aggressive periodontitis is a type of periodontitis with early onset and rapid progression and mostly affecting young adults who occupy a large percentage of orthodontic patients. The role of the orthodontist is important in screening the disease, making a provisional diagnosis, and referring it to a periodontist for immediate treatment. The orthodontist should be aware of the disease not only before starting the appliance therapy, but also during and after the active mechanotherapy. The orthodontic treatment plan, biomechanics, and appliance system may need to be modified to deal with the teeth having reduced periodontal support. With proper force application and oral hygiene maintenance, orthodontic tooth movement is possible without any deleterious effect in the tooth with reduced bone support. With proper motivation and interdisciplinary approach, orthodontic treatment is possible in patients with controlled aggressive periodontitis.

Neutrophil priming: Implications in periodontal disease

Periodontal disease is a well-regulated response to bacterial infection directed by the inflammatory cells of the host immune system. The host response to injury or insult is implicated to be a vital feature of the majority of periodontal diseases. The excessive activation of neutrophils plays a role in the pathogenesis in diseases such as acute respiratory distress syndrome, rheumatoid arthritis, and periodontitis by contributing to inflammatory tissue injury. In the recent times, there has been a shift of paradigm from a hypo- to hyper-responsive/primed model of neutrophil dysfunction in periodontal etiopathogenesis. The aim of this review is to outline the mechanisms and effects of neutrophil priming, and thereafter, discuss the current controversy that exists regarding the role of primed neutrophils in periodontal etiopathogenesis.

Artificial neural networks for the diagnosis of aggressive periodontitis trained by immunologic parameters

There is neither a single clinical, microbiological, histopathological or genetic test, nor combinations of them, to discriminate aggressive periodontitis (AgP) from chronic periodontitis (CP) patients. We aimed to estimate probability density functions of clinical and immunologic datasets derived from periodontitis patients and construct artificial neural networks (ANNs) to correctly classify patients into AgP or CP class. The fit of probability distributions on the datasets was tested by the Akaike information criterion (AIC). ANNs were trained by cross entropy (CE) values estimated between probabilities of showing certain levels of immunologic parameters and a reference mode probability proposed by kernel density estimation (KDE). The weight decay regularization parameter of the ANNs was determined by 10-fold cross-validation. Possible evidence for 2 clusters of patients on cross-sectional and longitudinal bone loss measurements were revealed by KDE. Two to 7 clusters were shown on datasets of CD4/CD8 ratio, CD3, monocyte, eosinophil, neutrophil and lymphocyte counts, IL-1, IL-2, IL-4, INF-γ and TNF-α level from monocytes, antibody levels against A. actinomycetemcomitans (A.a.) and P.gingivalis (P.g.). ANNs gave 90%-98% accuracy in classifying patients into either AgP or CP. The best overall prediction was given by an ANN with CE of monocyte, eosinophil, neutrophil counts and CD4/CD8 ratio as inputs. ANNs can be powerful in classifying periodontitis patients into AgP or CP, when fed by CE values based on KDE. Therefore ANNs can be employed for accurate diagnosis of AgP or CP by using relatively simple and conveniently obtained parameters, like leukocyte counts in peripheral blood. This will allow clinicians to better adapt specific treatment protocols for their AgP and CP patients.

Mathematical modeling suggests that periodontitis behaves as a non-linear chaotic dynamical process

BACKGROUND

This study aims to expand on a previously presented cellular automata model and further explore the non-linear dynamics of periodontitis. Additionally the authors investigated whether their mathematical model could predict the two known types of periodontitis, aggressive (AgP) and chronic periodontitis (CP).

METHODS

The time evolution of periodontitis was modeled by an iterative function, based on the hypothesis that the host immune response level determines the rate of periodontitis progression. The chaotic properties of this function were investigated by direct iteration, and the model was validated by immunologic and clinical parameters derived from two clinical study populations.

RESULTS

Periodontitis can be described as chaos with the level of the host immune response determining its progression rate; the dynamics of the proposed model suggest that by increasing the host immune response level, periodontitis progression rate decreases. Renormalization transformations show the presence of two overlapping zones of disease activity corresponding to AgP and CP. By k-means cluster analysis, immunologic parameters corroborated the findings of the renormalization transformations. Periodontitis progression rates are modeled to scale with a power law of 1.3, and the mean exponential speed of the system is found to be 1.85 (metric entropy); clinical datasets confirmed the mathematical estimates.

CONCLUSIONS

This study introduces a mathematical model that identifies periodontitis as a non-linear chaotic process. It offers a quantitative assessment of the disease progression rate and identifies two zones of disease activity that correspond to the existing classification of periodontitis in the AgP and CP types.

Aggressive periodontitis defined by recursive partitioning analysis of immunologic factors

BACKGROUND

The present study aims to extend recent findings of a non-linear model of the progression of periodontitis supporting the notion that aggressive periodontitis (AgP) and chronic periodontitis (CP) are distinct clinical entities. This approach is based on the implementation of recursive partitioning analysis (RPA) to evaluate a series of immunologic parameters acting as predictors of AgP and CP.

METHODS

RPA was applied to three population samples, that were retrieved from previous studies, using 17 immunologic parameters. The mean values of the parameters in control subjects were used as the cut-off points. Leave-one-out cross-validation (LOOCV) prediction errors were estimated in the proposed models, as well as the Kullback-Leibler divergence (DKL) of the distribution of positive results in AgP compared to CP and negative results in CP compared to AgP.

RESULTS

Seven classification trees were derived showing that the relationship of interleukin (IL)-4, IL-1, IL-2 has the highest potential to rule out or rule in AgP. On the other hand, immunoglobulin (Ig)A, IgM used to rule out AgP and cluster of differentiation 4 (CD4)/CD8, CD20 used to rule in AgP showed the least LOOCV cost. Penalizing DKL with LOOCV cost promotes the IL-4, IL-1, IL-2 model for ruling out AgP, whereas the single CD4/CD8 ratio with a lowered discrimination cut-off point was used to rule in AgP.

CONCLUSIONS

Although a test is unlikely to have both high sensitivity and high specificity, the use of immunologic parameters in the right model can efficiently complement a clinical examination for ruling out or ruling in AgP.

How has neutrophil research improved our understanding of periodontal pathogenesis?

BACKGROUND

Neutrophils are the predominant cells responsible for host defence against bacterial infection. Loss of neutrophil defence, due either to deficient number or function, strongly predisposes to bacterial infections such as periodontitis. Yet, the neutrophil oxidative and proteolytic arsenal has also been implicated in perpetrating periodontal tissue damage in periodontitis.

AIM

In this review, we focus on recent developments that shed light on these two aspects of neutrophil function in periodontitis.

METHODS

Primary search: using PubMed search for "neutophil", "periodontal", and "periodontitis". Secondary search: using references from the articles found in the first stage.

RESULTS

Early histological studies showed that infiltrating neutrophils form a wall of cells abutting the junctional epithelium in periodontal inflammatory lesions. The chronic standoff between these neutrophils and the bacterial community suggests that bacterial evasion of neutrophil clearance is a major characteristic of periodontitis. Indeed, not all functional neutrophil deficiencies increase the risk of periodontitis, an observation that points the way towards identification of particular anti-bacterial pathways essential for protection against periodontal pathogens. The net result in the majority of periodontitis patients who exhibit normal neutrophil number and function, is that neutrophils accumulate in the periodontal tissue where they are available to participate in tissue destruction. Diminished neutrophil clearance further contributes to the persistence of activated neutrophils in the periodontal tissue.

CONCLUSIONS

Data on the role of neutrophils in the pathogenesis of periodontitis are mixed. Neutrophils are a critical arm of the defence against periodontitis, but bacterial evasion of the neutrophil microbicidal machinery coupled with delayed neutrophil apoptosis may transform the neutrophil from defender to perpetrator. At this stage of knowledge, attempts to induce host modulation through neutrophil suppression or activation are premature.

Prognosis of periodontitis recurrence after intensive periodontal treatment using examination of serum IgG antibody titer against periodontal bacteria

Chronic periodontitis is associated with systemic diseases such as atherosclerosis. In this study, we evaluated the efficacy of serum IgG antibody titer to periodontal bacteria for prognosis of periodontitis recurrence during supportive periodontal therapy (SPT) phase. The 139 patients during SPT phase were selected and divided to two groups as follows: "Stable" and "Recurrence" group at SPT phase for case-control study: "High IgG titer" and "Normal IgG titer" group before transition to SPT phase for cohort study. We examined whether clinical findings or serum IgG antibody titers to periodontal bacteria are risk factors for the development of periodontitis recurrence. Case-control study showed that there were significant differences between the stable and recurrence groups in age and number of teeth. The serum IgG antibody titer to Eikenella corrodens FDC1073, Porphyromonas gingivalis SU63, and Campylobacter rectus ATCC33238 was significantly higher in the recurrence group. Next, we found, that the recurrence ratio in the high IgG titer group to Gram-negative obligate anaerobe, Prevotella intermedia, Treponema denticola, and C. rectus was significantly higher than that of the normal IgG titer group. Taken together, serum IgG antibody titer test is useful in the prognosis of periodontitis recurrence during the SPT phase.

Decreased interleukin-2 responses to Fusobacterium nucleatum and Porphyromonas gingivalis in generalized aggressive periodontitis

BACKGROUND

Compromised T-cell responses to periodontal pathogens may contribute to the pathogenesis of generalized aggressive periodontitis (GAgP). In this study, we attempted to characterize T-helper cell (Th1, Th2, and Th17) responses in patients with GAgP and healthy controls upon stimulation with disease-relevant pathogens.

METHODS

Mononuclear cells (MNCs) from 10 white patients with GAgP and 10 white controls were stimulated with Porphyromonas gingivalis American Type Culture Collection (ATCC) 33277 (Pg), Prevotella intermedia ATCC 25611, Fusobacterium nucleatum ATCC 49256 (Fn), and similar bacteria isolated from the participants' inherent oral flora. Tetanus toxoid (TT) was used as control antigen. The resulting production of interferon-gamma (IFN-gamma) and interleukin (IL)-2, -4, -5 and -17 and the induced proliferation of CD4+ T cells were measured.

RESULTS

MNCs from patients with GAgP exhibited decreased IL-2 responses to Pg and Fn. No difference was observed between patients with GAgP and controls with regard to CD4+ T-cell proliferation or the production of IFN-gamma and IL-4, -5, and -17, irrespective of whether type strains or bacteria isolated from the participants' oral cavity were used for stimulation. Moreover, similar proliferative and cytokine responses to TT were observed. Notably, smoking patients with GAgP exhibited significantly lower IFN-gamma responses to the bacteria and to TT than non-smoking patients or controls.

CONCLUSIONS

The decreased IL-2 responses of patients with GAgP to Pg and Fn combined with adequate IL-2 responses to TT suggest an impaired antigen-specific T-cell reactivity with periodontal pathogens in GAgP. The decreased IFN-gamma responses of smokers within the patient group suggest that smoking may aggravate this impairment.

Relationship of neutrophil phagocytosis and oxidative burst with the subgingival microbiota of generalized aggressive periodontitis

INTRODUCTION

Polymorphonuclear neutrophil (PMN) dysfunctions have been associated with severe forms of periodontitis. This study evaluated the correlation between PMN phagocytosis and oxidative burst with the subgingival microbiota of patients with generalized aggressive periodontitis (GAgP).

METHODS

Heparinized peripheral blood samples were obtained from 18 GAgP patients and 11 periodontally healthy (PH) subjects, and PMNs were isolated on a Ficoll-Hypaque gradient. For phagocytosis analysis, PMNs were incubated with fluorescein-labeled Staphylococcus aureus. The oxidative burst was evaluated by incubation of PMNs with dihydroethidium and activation by S. aureus. The assays were examined using flow cytometry. Subgingival biofilm samples were obtained from periodontal sites with and without periodontitis and 24 species were detected by checkerboard.

RESULTS

A significantly lower phagocytosis rate was observed for patients with GAgP compared with PH subjects over time (P < 0.05). No differences between groups were found for superoxide production. GAgP patients presented significantly higher prevalence and levels of Porphyromonas gingivalis, Tannerella forsythia, and Aggregatibacter actinomycetemcomitans serotype b than controls (P < 0.05). Significant negative correlations between T. forsythia and P. gingivalis and PMN functions were observed.

CONCLUSIONS

GAgP subjects presented diminished phagocytic activity of peripheral PMNs and high prevalence and levels of classical periodontal pathogens.

Matrix metalloproteinase levels in children with aggressive periodontitis

BACKGROUND

Matrix metalloproteinases (MMPs) are a family of host-derived proteinases reported to mediate multiple functions associated with periodontal destruction and inflammation. Most of the existing data have been gathered from adults with chronic periodontitis. The purpose of this study was to determine the MMP levels in a cohort of African American children with and without aggressive periodontitis.

METHODS

Gingival crevicular fluid (GCF) was collected in a cohort of 44 African American children, 7 to 19 years of age, with and without aggressive periodontitis (AgP) and compared to healthy unrelated children and to adults with chronic periodontitis (CP). GCF volume was determined with a calibrated gingival fluid meter. The samples were assayed for MMP-1, -2, -3, -8, -9, -12, and -13 using fluorimetric substrates.

RESULTS

The MMP levels from diseased sites in the subjects with AgP were statistically higher (P <0.05) in almost all instances than those associated with the unrelated controls or with the subjects with CP. MMP-8 was significantly elevated in the diseased sites of the children with AgP relative to non-diseased sites in the same children (P = 0.002), as well as the siblings, non-diseased controls, and subjects with CP (P < or =0.0001). There was no positive correlation between probing depth and any MMP level.

CONCLUSIONS

MMP levels were elevated in AgP sites relative to non-diseased sites in the same subjects, in siblings, and in unrelated controls. MMPs associated with the AgP sites in children were generally elevated compared to an adult cohort with a history of CP.

Controlled-delivery chlorhexidine chip versus amoxicillin/metronidazole as adjunctive antimicrobial therapy for generalized aggressive periodontitis: a randomized controlled clinical trial

BACKGROUND

Subgingival application of chlorhexidine via a controlled-delivery device (CHX chip) improves the clinical outcome of scaling/root planing (SRP) in therapy for chronic periodontitis. Generalized aggressive periodontitis (GAP) is commonly treated with SRP and adjunctive antimicrobial medication. To date, the efficacy of CHX chips in GAP therapy has not been evaluated.

AIM

To compare SRP plus adjunctive CHX chip placement with SRP plus adjunctive systemic amoxicillin/metronidazole with regard to clinical efficacy in first-line therapy for GAP.

MATERIAL AND METHODS

Thirty-six GAP patients were treated with SRP and randomly with either placement of CHX chips or systemic amoxicillin/metronidazole. Clinical attachment level (CAL), probing depth (PD), bleeding on probing (BoP) and suppuration (Pus) were measured at baseline, 3 and 6 months after therapy.

RESULTS

CAL, PD, BoP and Pus were significantly reduced in both groups after 3 months. In the CHX chip group, PD significantly increased again between 3 and 6 months. Finally, amoxicillin/metronidazole patients presented significantly more CAL "gain", PD reduction and less remaining deep sites after 6 months. Pus remained detectable in CHX chip patients only.

CONCLUSIONS

In first-line non-surgical therapy for GAP, SRP plus adjunctive systemic amoxicillin/metronidazole was more efficacious in clinically relevant measures of outcome than SRP plus adjunctive placement of CHX chips.

Effects of periodontal therapy on serum C-reactive protein, sE-selectin, and tumor necrosis factor-? secretion by peripheral blood-derived macrophages in diabetes. A pilot study

BACKGROUND AND OBJECTIVE

Diabetes is associated with an increased risk for vascular disease and periodontitis. The aim of this study was to assess the effects of periodontal treatment in diabetes with respect to alterations in the pro-inflammatory potential of peripheral blood mononuclear cells.

MATERIAL AND METHODS

Ten patients with diabetes and moderate to severe periodontitis received full-mouth subgingival debridement. Blood samples for serum/plasma and mononuclear cell isolation were collected prior to and 4 wk after therapy. Mononuclear cells were analyzed by flow cytometry and stimulated with lipopolysaccharide or ionomycin/phorbol ester to determine the pro-inflammatory capacity of macrophages and lymphocytes, respectively.

RESULTS

Following periodontal treatment, all patients demonstrated a significant improvement in clinical periodontal status (p < 0.05), despite only modest reduction in subgingival bacterial load or homologous serum immunoglobulin G titers. CD14(+) blood monocytes decreased by 47% (p < 0.05), and the percentage of macrophages spontaneously releasing tumor necrosis factor-alpha decreased by 78% (p < 0.05). There were no significant changes in the capacity of lymphocytes to secrete interferon-gamma. Among a number of serum inflammatory markers tested, high-sensitivity-C-reactive protein significantly decreased by 37% (p < 0.01) and soluble E-selectin decreased by 16.6% (p < 0.05).

CONCLUSION

These data suggest a reduced tendency for monocyte/macrophage-driven inflammation with periodontal therapy and a potential impact on atherosclerosis-related complications in diabetic individuals.

The association of the composite IL-1 genotype with periodontitis progression and/or treatment outcomes: a systematic review

BACKGROUND

Genetically transmitted traits such as cytokine gene polymorphisms may accentuate the host inflammatory response to the bacterial challenge and influence susceptibility to periodontitis.

OBJECTIVE

To systematically review the evidence of an association between the interleukin-1 (IL-1) composite genotype, i.e. presence of the allele 2 in the gene clusters IL-1A-889 and in IL-1B +3953, and periodontitis progression and/or treatment outcomes.

MATERIAL AND METHODS

Based on the focused question, a search was conducted for longitudinal clinical trials comparing progression of periodontitis and/or treatment outcomes in IL-1 genotype-positive (carrying allele 2) and IL-1 genotype-negative (not carrying allele 2) subjects. A search in the National Library of Medicine computerized bibliographic database MEDLINE and a manual search were performed. Selection of publications, extraction of data and validity assessment were made independently by two reviewers.

RESULTS

The search provided 122 titles of which 11 longitudinal publications were included. The heterogeneity of the data prevented the performance of a meta-analysis. While findings from some publications rejected a possible role of IL-1 composite genotype on progression of periodontitis after various therapies, other reported a prognostic value for disease progression of the positive IL-1 genotype status. When assessed on a multivariate risk assessment model, several publications concluded that the assessment of the IL-1 composite genotype in conjunction with other covariates (e.g. smoking and presence of specific bacteria) may provide additional information on disease progression. The small sample size of the available publications, however, requires caution in the interpretation of the results.

CONCLUSION

Based on these findings, (i) there is insufficient evidence to establish if a positive IL-1 genotype status contributes to progression of periodontitis and/or treatment outcomes. Therefore, (ii) results obtained with commercially available tests should be interpreted with caution.

Gingival crevicular fluid laminin-5 gamma2-chain levels in periodontal disease

AIM

Our study aimed to examine the molecular forms and gingival crevicular fluid (GCF) levels of laminin-5 gamma2-chain in patients with different periodontal disease, and compare the effects of P.gingivalis trypsin-like proteinase on intact laminin-5 gamma2-chain species.

METHODS

Eighteen patients with generalized aggressive periodontitis (G-AgP), 29 patients with chronic periodontitis (CP), 20 with gingivitis and 20 periodontally healthy subjects were included. Probing depth, clinical attachment loss, presence of bleeding on probing and plaque were recorded. Molecular forms and GCF laminin-5 gamma2-chain levels and the effects of P. gingivalis trypsin-like proteinase on intact laminin-5 gamma2-chain were analysed by computer-quantitated Western immunoblotting.

RESULTS

Laminin-5 gamma2-chain 40 and 70 kDa fragments could be detected in all groups, in varying levels. The CP group had elevated GCF laminin-5 gamma2-chain fragment levels compared with the gingivitis and healthy groups (p<0.008). The G-AgP group had GCF laminin-5 gamma2-chain fragment levels similar to the gingivitis and healthy groups (p>0.008). GCF laminin-5 gamma2-chain fragments differed clearly from the multiple lower molecular size fragments of P.gingivalis trypsin-laminin-5 gamma2-chain proteinases.

CONCLUSION

Increased GCF laminin-5 gamma2-chain fragments in periodontitis sites with deep periodontal pocket suggest that these cleaved 40 and 70 kDa fragments could reflect the extent of the inflammatory reaction in CP.

Characterization of Patients Presenting for Treatment to a University Refractory Periodontal Diseases Unit: Three Case Reports

BACKGROUND

Of the many forms of periodontal disease, refractory periodontal diseases are the least characterized. They are defined as the continued degeneration of the periodontium despite adequate management. This has led to the suggestion that there may be a systemic component that is a contributing factor to the development of this condition. The objectives of this report were to follow the progression of clinical changes associated with periodontal disease over a number of years in this unique population and review various hematologic and microbiologic factors that may be contributing to the disease progression.

METHODS

Three subjects were profiled. They were referred to the Refractory Periodontal Disease Unit at the University of Toronto by periodontists or general practitioners in the Southern Ontario region. Complete medical and dental histories were obtained along with baseline clinical measurements. Periodontal examinations were facilitated with the use of a computer-assisted periodontal probe. A microbiologic analysis using immunofluorescence techniques was able to detect Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, and Actinobacillus actinomycetemcomitans and spirochetes. A hematologic analysis, including a complete blood count (CBC), immune profile, and glycosylated hemoglobin assay, was also performed.

RESULTS

The clinical presentation revealed that patients receiving adequate maintenance therapy and with good to excellent oral hygiene demonstrated sites with continual loss of attachment. Few periodontal pathogens were detected. However, the most significant finding appeared to be the report elevated levels of CD8+ cells within this group of patients compared to normal laboratory ranges.

CONCLUSIONS

This report is an attempt at characterizing a unique population within the periodontal realm. The long-term monitoring of these patients allowed for an assessment of factors that may be involved in the continued decline of the periodontal health of these patients. Based on the immune profile, it is possible that a hyperresponsive state may be the primary feature of this population. Future assessments, including full-mouth interleukin (IL)-1 and matrix metalloproteinase (MMP)-8 levels, may assist in characterizing this population further, with the goal of producing markers that will assist clinicians in predicting treatment outcome.

The potential role of interleukin-17 in the immunopathology of periodontal disease

BACKGROUND

Interleukin-17 (IL-17) is exclusively produced by activated T cells, and this cytokine can induce inflammatory responses, support immune responses (Th1), and stimulate osteoclastic bone resorption in combination with receptor activator of NF-kappaB (RANK) and RANK ligand (RANKL). These biological functions are relevant to the aetiopathogenesis of periodontitis, and thus we sought to investigate whether IL-17 is produced in periodontal lesions and to assess the relationship of gene expression between IL-17 and other cytokines, and to determine the effect of IL-17 on IL-6 production in human gingival fibroblasts (HGF).

MATERIALS AND METHODS

IL-17 was detected and measured in periodontal tissues obtained as biopsy samples during periodontal surgery and in the cell-free culture supernatants cultured ex vivo, by using Western immunoblotting and enzyme-linked immunosorbent assay, respectively. IL-17 and other cytokine gene expression were investigated by the reverse transcription-polymerase chain reaction (RT-PCR) method. The contribution of IL-17 to IL-6 production by HGF was studied.

RESULTS

IL-17 protein was moderately detected in periodontal tissues. In contrast, IL-17 mRNA was expressed only in nine of 23 periodontitis tissue samples by RT-PCR. The IL-17 mRNA-positive samples simultaneously expressed mRNAs encoding interferon (IFN)-gamma, IL-2, RANK, and RANKL, but not IL-4. IL-10 (Th2 cytokine) was detected more frequently in the samples than IFN-gamma and IL-2 (Th1 cytokine). Recombinant human IL-17 induced IL-6 production from HGF in a dose- and time-dependent fashion.

CONCLUSIONS

These results indicate that IL-17 is produced in periodontal lesions, which may be involved in Th1 modulation and enhance inflammatory reactions via gingival fibroblast-derived mediators in periodontal disease. Thus, IL-17, together with other cytokines, has a potential role in the aetiopathogenesis of periodontal disease.

Gingival crevicular fluid monocyte chemoattractant protein-1 and RANTES levels in patients with generalized aggressive periodontitis

BACKGROUND

Local and systemic inflammatory and immune mechanisms may be implicated in the pathogenesis of the aggressive forms of periodontal disease. Chemokines, monocyte chemoattractant protein-1 (MCP-1) and regulated on activation, normal T cells expressed and secreted RANTES (regulated on activation, normal T cells expressed and secreted), are involved in the activation and recruitment of inflammatory and immune cells to the infected sites and thereby mediating a variety of pathophysiological conditions. The aim of the present study was to examine the gingival crevicular fluid (GCF) levels of MCP-1 and RANTES in patients with generalized agressive periodontitis (G-AgP).

METHODS

MCP-1 and RANTES levels were investigated in GCF samples of 10 patients with G-AgP and 10 periodontally healthy subjects. Periodontal status was evaluated by measuring probing depth, clinical attachment loss, presence of bleeding on probing and plaque. In the G-AgP group, GCF samples were collected from the two approximal sites; from one single-rooted tooth and from one first molar tooth with > or =6 mm probing depth. In the healthy group, GCF samples were collected from one of the single-rooted teeth. GCF MCP-1 and RANTES levels were quantified by enzyme immunoassay.

RESULTS

The G-AgP patients had significantly higher GCF MCP-1 and RANTES levels compared to the healthy group (p<0.05). GCF MCP-1 and RANTES levels were positively correlated with both probing depth and clinical attachment loss (p<0.05). There was no correlation between GCF MCP-1 and RANTES levels and the percentage of sites with bleeding (p>0.05).

CONCLUSIONS

The results of the present study suggest that MCP-1 and RANTES could play key roles in both activation and recruitment of inflammatory and immune cells in periodontal environment of G-AgP patients. In conclusion, these CC chemokines may be considered in the biological mechanism underlying the pathogenesis and progression of G-AgP.

Telomere Length in Leukocytes and Cultured Gingival Fibroblasts from Patients with Aggressive Periodontitis

BACKGROUND

The association of genetic risk factors with the pathogenesis of aggressive periodontitis (AgP) has been a focus of attention. Telomeres, which are nucleoprotein complexes at the ends of chromosomes, could be a genetic marker for Down's syndrome and Hutchinson-Gilford progeria, in which patients' premature aging is involved in the pathogenesis. It has been reported that these patients tend to experience severe periodontitis. Therefore, we investigated the telomere length of peripheral blood leukocytes (PBL) obtained from patients with AgP and that in the patients' gingival fibroblasts undergoing cellular aging in vitro.

METHODS

Twenty-one patients with AgP and 50 age-matched, periodontally healthy subjects (HS) participated in this study. Genomic DNA from PBL and from human gingival fibroblasts (HGF) was analyzed by Southern blotting for telomere length. The percentage of HGF positive for beta-galactosidase (beta-gal), a marker for cellular senescence, was also investigated.

RESULTS

There was no significant difference in the telomere length (P = 0.20, Student's t test) between the two groups, and wide interindividual variation was found (5.93 to 11.4 kbp, average 8.35 +/- 1.19 kbp). The telomere length from PBL negatively correlated with donor age, but no significant difference in telomere loss between the two groups was observed. With HGF undergoing aging in culture, the mean telomere length of these cells from six patients with AgP and seven HS decreased an average of -67.5 bp and -81.0 bp, respectively. No association was found in the telomere length between PBL and HGF from the same donors (r = 0.56, P = 0.20). A significant association was found between the telomere length and the percentages of beta-gal-positive HGF during cell passages (r = 0.70, P < 0.001).

CONCLUSIONS

These results indicate that patients with AgP do not have excessive telomere loss and thus do not support the notion of the occurrence of a generalized premature cellular aging in patients with AgP. Further studies are required to investigate the association between telomere length and beta-gal in HGF.