226 resultados para Actinobacillus-actinomycetemcomitans


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Background. Periodontal diseases (PDs) are infectious diseases in which periodontopathogens trigger chronic inflammatory and immune responses that lead to tissue destruction. Recently, viruses have been implicated in the pathogenesis of PDs. Individuals infected with human T lymphotropic virus 1 (HTLV-1) present with abnormal oral health and a marked increased prevalence of periodontal disease. Methods. In this study, we investigated the patterns of periodontopathogen infection and local inflammatory immune markers in HTLV-1-seropositive individuals with chronic periodontitis (CP/HTLV-1 group) compared with HTLV-1 -seronegative individuals with chronic periodontitis (CP group) and periodontally healthy, HTLV-1 -seronegative individuals (control group). Results. Patients in the CP/HTLV-1 group had significantly higher values of bleeding on probing, mean probing depth, and attachment loss than patients in the CP group. The expression of tumor necrosis factor a and interleukin (IL) 4 was found to be similar in the CP and CP/HTLV-1 groups, whereas IL-12 and IL-17 levels trended toward a higher expression in the CP/HTLV-1 group. A significant increase was seen in the levels of IL-1 beta and interferon gamma in the CP/HTLV-1 group compared with the CP group, whereas expression of the regulatory T cell marker FOXp3 and IL-10 was significantly decreased in the lesions from the CP/HTLV-1 group. Interestingly, similar frequency and/or load of periodontopathogens (Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Aggregatibacter actinomycetemcomitans) and frequency of viruses (herpes simplex virus 1, human cytomegalovirus, and Epstein-Barr virus) characteristically associated with PDs were found in the CP/HTLV and CP groups. Conclusions. HTLV-1 may play a critical role in the pathogenesis of periodontal disease through the deregulation of the local cytokine network, resulting in an exacerbated response against a standard periodontopathogen infection.

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Oral pathogens, including periodontopathic bacteria, are thought to be aetiological factors in the development of cardiovascular disease. In this study, the presence of Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum-periodonticum-simiae group, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Tannerella forsythia in atheromatous plaques from coronary arteries was determined by real-time PCR. Forty-four patients displaying cardiovascular disease were submitted to periodontal examination and endarterectomy of coronary arteries. Approximately 60-100 mg atherosclerotic tissue was removed surgically and DNA was obtained. Quantitative detection of periodontopathic bacteria was performed using universal and species-specific TaqMan probe/primer sets. Total bacterial and periodontopathic bacterial DNA were found in 94.9 and 92.3 %, respectively, of the atheromatous plaques from periodontitis patients, and in 80.0 and 20.0%, respectively, of atherosclerotic tissues from periodontally healthy subjects. All periodontal bacteria except for the F. nucleatum-periodonticum-simiae group were detected, and their DNA represented 47.3 % of the total bacterial DNA obtained from periodontitis; patients. Porphyromonas gingivalis, A. actinomycetemcomitans and Prevotella intermedia were detected most often. The presence of two or more periodontal species could be observed in 64.1 % of the samples. In addition, even in samples in which a single periodontal species was detected, additional unidentified microbial DNA could be observed. The significant number of periodontopathic bacterial DNA species in atherosclerotic tissue samples from patients with periodontitis suggests that the presence of these micro-organisms in coronary lesions is not coincidental and that they may in fact contribute to the development of vascular diseases.

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Background: Inhibitory signals mediated via molecules such as programmed death-1 (PD-1) play a critical role in downmodulating immune responses and maintaining peripheral tolerance. We investigated the involvement of cytokines and PD-1 engagement in mediating the T-cell unresponsiveness to bacterial and ubiquitous antigens in periodontal diseases. Methods: Gingival and peripheral blood samples from healthy individuals and patients with chronic periodontitis were collected and used for the subsequent assays. Leukocytes in the lesion site and blood were evaluated using flow cytometry. The production of interferon-gamma, interleukin-10, and transforming growth factor-P proteins was evaluated by enzyme-linked immunosorbent assay (ELISA), and the presence of PD-1+cells in the inflamed gingiva was confirmed by immunofluorescence confocal microscopy for CD4 and PD-1 colocalization. Results: T cells from patients with chronic periodontitis proliferated poorly in response to Aggregatibacter actinomycetem comitans (previously Actinobacillus actinomycetemcomitans) antigen. T-cell unresponsiveness was not associated with imbalanced cytokine production. However, T cells from patients with chronic periodontitis expressed significantly higher levels of PD-1 either upon isolation or after culture with antigens. Moreover, PD-1 blocking did not result in significant T-cell proliferation in cells cultured with phytohemagglutinin or bacterial antigens. The blockade of PD-1 resulted in the increased production of IFN-gamma. In addition, CD4+ and CD8+ T cells expressing PD-1 accumulated in lesions with chronic periodontitis. Conclusion: These data show that PD-1 engagement could be involved in the modulation of IFN-gamma production by T cells in patients with chronic periodontitis. J Periodontol 2009,80:1833-1844.

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Background and Objective: Inflammatory cytokines such as tumor necrosis factor-alpha are involved in the pathogenesis of periodontal diseases. A high between-subject variation in the level of tumor necrosis factor-alpha mRNA has been verified, which may be a result of genetic polymorphisms and/or the presence of periodontopathogens such as Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola (called the red complex) and Aggregatibacter actinomycetemcomitans. In this study, we investigated the effect of the tumor necrosis factor-alpha (TNFA) -308G/A gene polymorphism and of periodontopathogens on the tumor necrosis factor-alpha levels in the periodontal tissues of nonsmoking patients with chronic periodontitis (n = 127) and in control subjects (n = 177). Material and Methods: The TNFA-308G/A single nucleotide polymorphism was investigated using polymerase chain reaction-restriction fragment length polymorphism analysis, whereas the tumor necrosis factor-alpha levels and the periodontopathogen load were determined using real-time polymerase chain reaction. Results: No statistically significant differences were found in the frequency of the TNFA-308 single nucleotide polymorphism in control and chronic periodontitis groups, in spite of the higher frequency of the A allele in the chronic periodontitis group. The concomitant analyses of genotypes and periodontopathogens demonstrated that TNFA-308 GA/AA genotypes and the red-complex periodontopathogens were independently associated with increased levels of tumor necrosis factor-alpha in periodontal tissues, and no additive effect was seen when both factors were present. P. gingivalis, T. forsythia and T. denticola counts were positively correlated with the level of tumor necrosis factor-alpha. TNFA-308 genotypes were not associated with the periodontopathogen detection odds or with the bacterial load. Conclusion: Our results demonstrate that the TNFA-308 A allele and red-complex periodontopathogens are independently associated with increased levels of tumor necrosis factor-alpha in diseased tissues of nonsmoking chronic periodontitis patients and consequently are potentially involved in determining the disease outcome.

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Aim The microbial profile of localized aggressive periodontitis (LAgP) has not yet been determined. Therefore, the aim of this study was to evaluate the subgingival microbial composition of LAgP. Material and Methods One hundred and twenty subjects with LAgP (n=15), generalized aggressive periodontitis (GAgP, n=25), chronic periodontitis (ChP, n=30) or periodontal health (PH, n=50) underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analysed for their content of 38 bacterial species using checkerboard DNA-DNA hybridization. Results Red complex and some orange complex species are the most numerous and prevalent periodontal pathogens in LAgP. The proportions of Aggregatibacter actinomycetemcomitans were elevated in shallow and intermediate pockets of LAgP subjects in comparison with those with GAgP or ChP, but not in deep sites. This species also showed a negative correlation with age and with the proportions of red complex pathogens. The host-compatible Actinomyces species were reduced in LAgP. Conclusion A. actinomycetemcomitans seems to be associated with the onset of LAgP, and Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Campylobacter gracilis, Eubacterium nodatum and Prevotella intermedia play an important role in disease progression. Successful treatment of LAgP would involve a reduction in these pathogens and an increase in the Actinomyces species.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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O fumo é considerado importante fator predisponente para muitas doenças, incluindo-se as periodontopatias. Desde que as doenças periodontais representam a inter-relação entre os fatores de virulência da microbiota subgengival sobre um hospedeiro susceptível, foi objetivo avaliar a freqüência de isolamento de três periodontopatógenos em indivíduos sadios e pacientes com doença periodontal, fumantes ou não, com níveis variados de higiene bucal; verificar a relação entre o número de microrganismos produtores de sulfeto de hidrogênio na placa subgengival de fumantes e não fumantes e sua condição clínica. Foram examinados 189 pacientes e indivíduos sadios, dos quais 60 foram selecionados para análise microbiológica. O índice de placa foi registrado de acordo com o índice de O'Leary e os espécimes de placa subgengival coletados e processados de acordo com SLOTS35 (1982). A identificação dos isolados foi obtida pelas suas características morfocelulares, morfocoloniais e bioquímico-fisiológicas. Verificou-se que a freqüência de isolamento dos bastonetes anaeróbios produtores de pigmento negro, Fusobacterium nucleatum e bactérias produtoras de sulfeto de hidrogênio foi similar entre fumantes e não fumantes, sendo mais elevada nos pacientes com doença periodontal. Já Actinobacillus actinomycetemcomitans foi isolado mais freqüentemente em sadios fumantes do que sadios não fumantes.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Background: Smoking is a well-known risk factor for destructive periodontal disease, but its relationship with periodontal status and subgingival microbiota remains unclear. Inherent limitations of microbiological methods previously used may partly explain these mixed results, and real-time polymerase chain reaction (PCR) has been presented as a valid alternative. The aim of the present study was to investigate the clinical condition and microbiological profile of patients with chronic periodontitis as related to the habit of smoking.Methods: Fifty patients (33 to 59 years old), 25 smokers and 25 never-smokers, constituted the sample. The visible plaque index (VPI), gingival bleeding index (GBI), bleeding on probing (BOP), periodontal probing depth (PD), clinical attachment loss (CAL), and gingival crevicular fluid (GCF) volume were recorded. Real-time PCR quantified Porphyromonas gingivalis, Micromonas micros, Dialister pneumosintes, Actinobacillus actinomycetemcomitans and total bacteria in subgingival samples.Results: Smokers and never-smokers showed similar values for VPI, GBI, and BOP. Smokers had deeper PD in buccal/lingual sites and higher CAL independently of the tooth surface. The GCF volume was smaller in smokers, independent of the PD. Similar amounts of total bacteria and P. gingivalis were observed for both groups. Significantly higher numbers of D. pneumosintes and M. micros were present in smokers and associated with moderate and deep pockets. When heavy smokers were considered, higher counts of total bacteria, M. micros, and D. pneumosintes were observed.Conclusions: Smoking seems to have a detrimental impact on the periodontal status and microbiological profile of patients with periodontitis. Compared to never-smokers, smokers had deeper pockets, greater periodontal destruction, and higher counts of some putative periodontal pathogens.

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Matrix metal loprotease-13 (MMP-13) is induced by pro-inflammatory cytokines and increased expression is associated with a number of pathological conditions such as tumor metastasis, osteoarthritis, rheumatoid arthritis and periodontal diseases. MMP-13 gene regulation and the signal transduction pathways activated in response to bacterial LPS are largely unknown. In these studies, the role of the mitogen-activated protein kinase (MAPK) pathways in the regulation of MMP-13 induced by lipopolysaccharide was investigated. Lipopolysaccharide from Escherichia coli and Actinobacillus actinomycetemcomitans significantly (P < 0.05) increased MMP-13 steady-state mRNA (average of 27% and 46% increase, respectively) in murine periodontal ligament fibroblasts. MMP-13 mRNA induction was significantly reduced by inhibition of p38 MAP kinase. Immunoblot analysis indicated that p38 signaling was required for LPS-induced MMP-13 expression. Lipopolysaccharide induced proximal promoter reporter (-660/+32 mMMP-13) gene activity required p38 signaling. Collectively, these results indicate that lipopolysaccharide-induced murine MMP-13 is regulated by p38 signaling through a transcriptional mechanism.

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Purpose: The goal of this study was to evaluate microbiota and radiographic peri-implant bone loss associated with ligature-induced peri-implantitis. Materials and Methods: Thirty-six dental implants with 4 different surfaces (9 commercially pure titanium, 9 titanium plasma-sprayed, 9 hydroxyapatite, and 9 acid-etched) were placed in the edentulous mandibles of 6 dogs. After 3 months with optimal plaque control, abutment connection was performed. On days 0, 20, 40, and 60 after placement of cotton ligatures, both microbiologic samples and periapical radiographs were obtained. The presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Campylobacter spp, Capnocytophaga spp, Fusobacterium spp, beta-hemolytic Streptococcus, and Candida spp were evaluated culturally. Results: P intermedia/nigrescens was detected in 13.89% of implants at baseline and 100% of implants at other periods. P gingivalis was not detected at baseline, but after 20 and 40 days it was detected in 33.34% of implants and at 60 days it was detected in 29.03% of dental implants. Fusobacterium spp was detected in all periods. Streptococci were detected in 16.67% of implants at baseline and in 83.34%, 72.22%, and 77.42% of implants at 20, 40, and 60 days, respectively. Campylobacter spp and Candida spp were detected in low proportions. The total viable count analysis showed no significant differences among surfaces (P = .831), although a significant difference was observed after ligature placement (P < .0014). However, there was no significant qualitative difference, in spite of the difference among the periods. The peri-implant bone loss was not significantly different between all the dental implant surfaces (P = .908). Discussion and Conclusions: These data suggest that with ligature-induced peri-implantitis, both time and periodontal pathogens affect all surfaces equally after 60 days.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)