Sergio Bizzarro

Periodontitis is associated with platelet activation

There is an epidemiological association between periodontitis and cardiovascular disease (CVD). In periodontitis, low grade systemic inflammation and bacteremia occur regularly. Such events may contribute to platelet activation and subsequent pro-coagulant state. This study aimed to investigate platelet activation in periodontitis patients. The study is composed of two parts. In the first part, plasma levels of soluble(s) P-selectin and sCD40 ligand were measured as general markers of platelet activation in periodontitis patients (n=85) and in healthy controls (n=35). In the second part, surface-exposed P-selectin and the ligand-binding conformation of the glycoprotein IIb-IIIa complex (binding of PAC-1 antibody) were determined on individual platelets in whole blood of periodontitis patients (n=18) and controls (n=16). Patients had significantly elevated plasma levels of sP-selectin (P<0.001) and increased binding of PAC-1 on isolated platelets (P=0.033). Platelet activation was more pronounced in the patients with more severe periodontal disease, showing a severity-dependence. The levels of sCD40 ligand and of platelet-bound P-selectin were not increased. Periodontitis is associated with increased platelet activation. Since platelet activation contributes to a pro-coagulant state and constitutes a risk for atherothrombosis, platelet activation in periodontitis may partly explain the epidemiological association between periodontitis and CVD.

Subgingival microbiome in smokers and non-smokers in periodontitis: an exploratory study using traditional targeted techniques and a next-generation sequencing

AIM To compare the results of two targeted techniques to an open-ended technique in periodontitis patients, differentiated on the basis of smoking habit. MATERIALS & METHODS Thirty periodontitis patients (15 smokers and 15 non-smokers) provided subgingival plaque samples for 16S rRNA gene amplicon sequencing, culturing and quantitative polymerase chain reaction (qPCR). RESULTS No differences were found in the composition of the subgingival microbiome between smokers and non-smokers with culture and qPCR. With pyrosequencing, operational taxonomic units (OTUs) classified to genera Fusobacterium, Prevotella and Selenomonas were more abundant in smokers, while OTUs belonging to the genera Peptococcus and Capnocytophaga were more abundant in non-smokers. Principal coordinate analysis identified two clusters; one was composed mainly of smokers (80%) and revealed significantly lower taxonomic diversity, higher attachment loss and higher proportion of the genera Fusobacterium, Paludibacter and Desulfobubus. CONCLUSION In periodontitis, there is a difference in the composition of the subgingival microbiome between smokers and non-smokers, as revealed by pyrosequencing. This difference was not identified by the targeted techniques. Low taxonomic diversity was associated with higher disease severity, especially in smokers. This supports the hypothesis of the ecological microbial-host interaction in the severity of periodontal disease.

Highly specific protease-based approach for detection of porphyromonas gingivalis in diagnosis of periodontitis.

ABSTRACT Porphyromonas gingivalis is associated with the development of periodontitis. Here we describe the development of a highly specific protease-based diagnostic method for the detection of P. gingivalis in gingival crevicular fluid. Screening of a proteolytic peptide substrate library, including fluorogenic dipeptides that contain d-amino acids, led to the discovery of five P. gingivalis-specific substrates. Due to the presence of lysine and arginine residues in these substrates, it was hypothesized that the cleavage was mediated by the gingipains, a group of P. gingivalis-specific proteases. This hypothesis was confirmed by the observation that P. gingivalis gingipain knockout strains demonstrated clearly impaired substrate cleavage efficacy. Further, proteolytic activity on the substrates was increased by the addition of the gingipain stimulators dithiothreitol and l-cysteine and decreased by the inhibitors leupeptin and N-ethylmaleimide. Screening of saliva and gingival crevicular fluid of periodontitis patients and healthy controls showed the potential of the substrates to diagnose the presence of P. gingivalis proteases. By using paper points, a sensitivity of approximately 105 CFU/ml was achieved. P. gingivalis-reactive substrates fully composed of l-amino acids and Bz-l-Arg-NHPhNO2 showed a relatively low specificity (44 to 85%). However, the five P. gingivalis-specific substrates that each contained a single d-amino acid showed high specificity (96 to 100%). This observation underlines the importance of the presence of d-amino acids in substrates used for the detection of bacterial proteases. We envisage that these substrates may improve the specificity of the current enzyme-based diagnosis of periodontitis associated with P. gingivalis.

Microbial profiles at baseline and not the use of antibiotics determine the clinical outcome of the treatment of chronic periodontitis.

Antibiotics are often used in the treatment of chronic periodontitis, which is a major cause of tooth loss. However, evidence in favour of a microbial indication for the prescription of antibiotics is lacking, which may increase the risk of the possible indiscriminate use of antibiotics, and consequent, microbial resistance. Here, using an open-ended technique, we report the changes in the subgingival microbiome up to one year post-treatment of patients treated with basic periodontal therapy with or without antibiotics. Antibiotics resulted in a greater influence on the microbiome 3 months after therapy, but this difference disappeared at 6 months. Greater microbial diversity, specific taxa and certain microbial co-occurrences at baseline and not the use of antibiotics predicted better clinical treatment outcomes. Our results demonstrate the predictive value of specific subgingival bacterial profiles for the decision to prescribe antibiotics in the treatment of periodontitis, but they also indicate the need for alternative therapies based on ecological approaches.

A Lead ANRIL Polymorphism Is Associated with Elevated CRP Levels in Periodontitis: A Pilot Case-Control Study.

Elevated high sensitive C-reactive protein (hsCRP) is a marker for systemic inflammation and a risk marker for atherosclerotic cardiovascular disease (ACVD), and has also been associated with periodontitis. Inter-individual variation for hsCRP in periodontitis has been shown. ANRIL is the strongest genetic susceptibility locus for both periodontitis and ACVD, and it is speculated that genetic variation in ANRIL may modulate inflammatory processes. Therefore, we explored the possible association between hsCRP plasma levels and a leading ANRIL single nucleotide polymorphism (SNP) in periodontitis patients and controls. 171 healthy subjects with North European descent (115 periodontitis and 56 controls) were included in this case-control study. hsCRP levels were determined and subjects were genotyped for the leading ANRIL SNP rs1333048. In a multivariate analysis, periodontitis, female gender, increasing BMI and homozygosity for the major allele (AA-genotype) of rs1333048 were significantly associated with elevated hsCRP plasma levels (p = 0.012, p = 0.004, p = 0.007 and p = 0.003, respectively). Periodontitis patients with rs1333048 AA-genotype showed higher levels of hsCRP than those carrying the minor C allele (median: 4.5 mg/L vs. 1.6 mg/L, padjusted = 0.007). This study is the first to show that, in addition to gender and BMI, also a leading SNP in ANRIL is explanatory for inter-individual variation in hsCRP levels in periodontitis patients of North European descent.

Association of serum immunoglobulin G (IgG) levels against two periodontal pathogens and prothrombotic state: a clinical pilot study

ObjectivePeriodontitis is associated with cardiovascular diseases (CVD). In our previous studies a prothrombotic state has been observed in periodontitis, which contributes to the risk of CVD. The aim of this study was to investigate whether serum IgG levels against Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) in periodontitis were associated with a prothrombotic state.Materials and methodsPatients with moderate (n = 38) and severe periodontitis (n = 30) and controls (n = 24) were recruited. We explored correlations between serum anti-Aa and anti-Pg IgG and plasma levels of markers of prothrombotic state (von Willebrand Factor [vWF], prothrombin fragment 1+2 [F1+2], plasminogen activator inhibitor-1 [PAI-1] and D-dimer). Multivariate analyses were performed considering several major potential contributing factors.ResultsPeriodontitis patients showed higher anti-Aa IgG (p = 0.015) than controls but not for Pg (p = 0.320). In periodontitis patients, body mass index and anti-Aa IgG showed a positive correlation with vWF (β = 0.297, p = 0.010 and β = 0.248, p = 0.033 respectively).ConclusionsIn periodontitis, infection with Aa together with other well accepted risk factors for CVD, may play a role in increasing the risk for prothrombotic state.

Comment on “Aggregatibacter actinomycetemcomitans–induced hypercitrullination links periodontal infection to autoimmunity in rheumatoid arthritis”

The link between rheumatoid arthritis and exposure to a bacterial toxin was not found in a population of rheumatoid arthritis patients from Netherlands. The link between rheumatoid arthritis and exposure to a bacterial toxin was not found in a population of rheumatoid arthritis patients from Netherlands.

Reduced platelet hyper-reactivity and platelet-leukocyte aggregation after periodontal therapy

BackgroundPlatelets from untreated periodontitis patients are hyper-reactive and form more platelet-leukocyte complexes compared to cells from individuals without periodontitis. It is not known whether the improvement of the periodontal condition achievable by therapy has beneficial effects on the platelet function. We aimed to assess the effects of periodontal therapy on platelet reactivity.MethodsPatients with periodontitis (n = 25) but unaffected by any other medical condition or medication were included and donated blood before and after periodontal therapy. Reactivity to ADP or oral bacteria was assessed by flow cytometric analysis of membrane markers (binding of PAC-1, P-selectin, CD63) and platelet-leukocyte complex formation. Reactivity values were expressed as ratio between the stimulated and unstimulated sample. Plasma levels of soluble (s) P-selectin were determined by enzyme-linked immunosorbent assay (ELISA).ResultsBinding of PAC-1, the expression of P-selectin and CD63 in response to the oral bacterium P. gingivalis were lower at recall (1.4 ± 1.1, 1.5 ± 1.2, and 1.0 ± 0.1) than at baseline (2.7 ± 4.1, P = 0.026, 6.0 ± 12.5, P = 0.045, and 2.7 ± 6.7, P = 0.042, respectively). Formation of platelet-leukocyte complexes in response to P. gingivalis was also reduced at recall compared to baseline (1.2 ± 0.7 vs. 11.4 ± 50.5, P = 0.045). sP-selectin levels were significantly increased post-therapy.ConclusionsIn periodontitis patients, the improvement of the periodontal condition is paralleled by a reduction in platelet hyper-reactivity. We suggest that periodontal therapy, as an intervention for improved oral health, can facilitate the management of thrombotic risk, and on the long term can contribute to the prevention of cardiovascular events in patients at risk.Trial registrationCurrent Controlled Trials identifier ISRCTN36043780. Retrospectively registered 25 September 2013.

Effect of periodontal therapy with systemic antimicrobials on parameters of metabolic syndrome: A randomized clinical trial

Abstract Aim To investigate the effect of basic periodontal therapy (BPT) with antimicrobials (AM) on the parameters of metabolic syndrome (MetS) (waist circumference, systolic/diastolic blood pressure [BP], HDL‐cholesterol, triglycerides, glucose). Methods One hundred and ten periodontitis patients without known comorbidities and unaware of possible MetS were randomly assigned to BPT (n = 56) or BPT+AM (n = 54) and followed for 12 months post‐therapy. Number of patients with undiagnosed MetS was also determined. Results In all patients, the periodontal condition improved; however, the BTP+AM group showed greater pocket depth reduction than the BPT group. Post‐therapy, systolic BP (p < .05) and triglycerides (p < .05) reduced significantly during the follow‐up period. No significant differences could be assessed between the BPT+AM and BPT group. Despite the absence of self‐reported comorbidities, 27.2% (n = 30) periodontitis patients fulfilled the criteria of MetS at baseline. After therapy, this proportion changed to 14.5% at 3 months (p = .007), to 17.3% at 6 months (p = .017) and to 21.8% at 12‐month follow‐up (p = .383). Conclusion Although a reduction in systolic BP and triglycerides and a temporarily improvement in the whole metabolic status were observed, the use of antimicrobials in conjunction with BTP does not yield any additional improvement in the parameters of MetS.