Gilson Cesar Nobre Franco

Etiological analysis of initial colonization of periodontal pathogens in oral cavity.

ABSTRACT It is unclear when the initial colonization by periodontal pathogens occurs in the oral cavity. Therefore, we report here the association between specific age groups and the time when the initial colonization by periodontal pathogens occurs in the oral cavity in such groups. Findings are based on an epidemiological analysis of the prevalence of five periodontal pathogens in the oral cavities of a wide range of age populations, from newborn to elderly, who were randomly selected in a geographic region of Brazil. These periodontal pathogens include Campylobacter rectus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Tannerella forsythia and were analyzed in the bacterial samples isolated from gingival sulcus, the dorsum of the tongue, and cheek mucosa of diverse age groups, using a bacterial DNA-specific PCR method. Results indicated that there are distinct age-related groups where initial colonization by the five periodontal pathogens examined in this study can be detected and that the presence of teeth is a permissive factor for colonization by P. gingivalis, P. intermedia, and T. forsythia. Although it remains unclear exactly how or when target pathogens colonize healthy subjects, an understanding of age-related groups does provide a potentially useful tool in the early detection and prevention of periodontitis in healthy individuals.

Fluoxetine inhibits inflammatory response and bone loss in a rat model of ligature-induced periodontitis

BACKGROUND Fluoxetine, a selective serotonin reuptake inhibitor, has been found recently to possess anti-inflammatory properties. The present study investigates the effects of fluoxetine on inflammatory tissue destruction in a rat model of ligature-induced periodontal disease. METHODS Thirty male Wistar rats were randomly assigned into three groups (n = 10 animals per group): 1) control rats (without ligature); 2) rats with ligature + placebo (saline; oral gavage); and 3) rats with ligature + fluoxetine (20 mg/kg/day in saline; oral gavage). Histologic analyses were performed on the furcation region and mesial aspect of mandibular first molars of rats sacrificed at 15 days after ligature-induced periodontal disease. Reverse transcription-polymerase chain reaction and zymography were performed to analyze the mRNA expression of interleukin (IL)-1β, cyclooxygenase (COX)-2, matrix metalloproteinase (MMP)-9 and inducible nitric oxide synthase and the MMP-9 activity, respectively, in gingival tissues samples. RESULTS Compared to the ligature + placebo group, alveolar bone loss was reduced in the fluoxetine group (P <0.05), and the amount of collagen fibers in the gingival tissue was maintained. Moreover, in gingival tissue sampled 3 days after ligature attachment, fluoxetine administration reduced IL-1β and COX-2 mRNA expression. Fluoxetine downregulated MMP-9 activity, without affecting MMP-9 mRNA expression induced by ligature, compared to the ligature + placebo group (P <0.05). These data suggest that fluoxetine suppressed proinflammatory responses, as well as proteolytic enzyme activity, induced by ligature. CONCLUSION In the present study, fluoxetine suppresses the inflammatory response and protects against periodontal bone resorption and destruction of collagen fibers, suggesting that fluoxetine can constitute a promising therapeutic approach for periodontal diseases.

The effects of nicotine and cotinine on Porphyromonas gingivalis colonisation of epithelial cells.

Smoking is a risk factor for development of periodontitis. Porphyromonas gingivalis is an important colonizer of the subgingival crevice and is a major pathogenic agent in the initiation and progression of severe forms of periodontal disease. However, the effect of major cigarettes derivatives on P. gingivalis is poorly understood. The purpose of this study was to determine the influence of nicotine and cotinine on bacterial colonisation to epithelial cells. KB cells monolayers and P. gingivalis ATCC 33277 were exposed to 0.1, 10 and 100 microg/mL of nicotine and cotinine concentrations. The epithelial cells were incubated for 24 h while P. gingivalis was exposed to these substances until reach early logarithmic phase. After the incubation period, P. gingivalis ability to colonize KB cells was assayed. The number of cell-associated/invasive bacteria was assessed by counting the colony-forming units. 100 microg/mL cotinine significantly increased P. gingivalis association and invasion of epithelial cells, when the bacteria was exposed to this substance (p<0.05; ANOVA-Tukey test). No other condition or drug altered the bacteria colonisation ability (p>0.05). These data indicated that cotinine may interfere with P. gingivalis ability to associate and invade the epithelial cells. Further studies are needed to investigate whether oral cells might be more susceptible to be colonized by P. gingivalis in smokers.

Essential oils in one-stage full-mouth disinfection: double-blind, randomized clinical trial of long-term clinical, microbial and salivary effects.

AIM This randomized clinical trial evaluated the effects of an essential oils-containing mouthrinse for full-mouth disinfection. MATERIAL AND METHODS Fifty patients were assigned to receive full-mouth disinfection with either essential oils or placebo. At baseline, 2 and 6 months of treatment the primary outcomes probing depth (PD), plaque index (PlI) and modified gingival index (MGI) were monitored. Additional monitoring included bacterial presence (by polymerase chain reaction) in subgingival, saliva and tongue samples; flows, pH, total protein and alkaline phosphatase salivary levels. The following statistics were used: ANOVA, Students t-test, chi(2) and Kruskal-Wallis (p<0.05). RESULTS Mean PD>or=3.5 mm was reduced over time in both the placebo and the test groups, but there was no difference in PD reduction between groups at 2 and 6 months. At 2 and 6 months, PlI and MGI showed greater reductions in the test group than in the placebo group. Porphyromona gingivalis was not reduced in any site. At 6 months, Campylobacter rectus increased in both groups, while Tannerella forsythensis decreased subgingivally in the test group. S. sanguinis increased, except subgingivally, in the placebo group. Salivary pH and flows were not altered. Total protein reduced only in the test group. Alkaline phosphatase did not change in either group. CONCLUSIONS Essential oils for full-mouth disinfection showed clinical benefits, namely reducing plaque and gingival inflammation without altering basic salivary parameters.

Statins and Antimicrobial Effects: Simvastatin as a Potential Drug against Staphylococcus aureus Biofilm

Statins are important lipid-lowering agents with other pleiotropic effects. Several studies have explored a possible protective effect of statins to reduce the morbidity and mortality of many infectious diseases. Staphylococcus aureus is one of the main pathogens implicated in nosocomial infections; its ability to form biofilms makes treatment difficult. The present study observed the MIC of atorvastatin, pravastatin and simvastatin against S. aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis. Simvastatin was the only agent with activity against clinical isolates and reference strains of methicilin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). Thus, the effects of simvastatin on the growth, viability and biofilm formation of S. aureus were tested. In addition, a possible synergistic effect between simvastatin and vancomycin was evaluated. Simvastatin’s MIC was 15.65 µg/mL for S. aureus 29213 and 31.25 µg/mL for the other strains of S. aureus. The effect of simvastatin was bactericidal at 4xMIC and bacteriostatic at the MIC concentration. No synergistic effect was found between simvastatin and vancomycin. However, the results obtained against S. aureus biofilms showed that, in addition to inhibiting adhesion and biofilm formation at concentrations from 1/16xMIC to 4xMIC, simvastatin was also able to act against mature biofilms, reducing cell viability and extra-polysaccharide production. In conclusion, simvastatin showed pronounced antimicrobial activity against S. aureus biofilms, reducing their formation and viability.

Gingival overgrowth in subjects under immunosuppressive regimens based on cyclosporine, tacrolimus, or sirolimus

AIM To assess the prevalence and variables associated with gingival overgrowth (GO) in renal transplant recipients medicated with cyclosporine (CsA), tacrolimus (Tcr), or sirolimus (Sir). MATERIALS AND METHODS One hundred and thirty-five eligible subjects were divided in CsA, Tcr, and Sir groups comprising 45 subjects each. GO was visually assessed and subjects were assigned as GO+ or GO- in a post hoc definition. Saliva samples were collected and the presence of periodontal pathogens was assessed through polymerase chain reaction. Variables of interest were compared between GO+ and GO- subjects through univariate and multivariate analysis. RESULTS Prevalence of GO was of 60.0% for CsA, 28.9% for Tcr, and 15.6% for Sir groups. Within the CsA group, GO was associated with papillary bleeding index (p=0.001); within the Tcr group, GO was associated with CsA previous use (p=0.013), and calcium channel blockers (CCB) use (p=0.003); within the Sir group, GO was associated with papillary bleeding index (p=0.018), and CCB use (p=0.020). A higher frequency of Tannerella forsythia was observed among GO+ subjects medicated with Tcr. CONCLUSION Pharmacological and periodontal variables were associated with GO in different immunosuppressive regimens. Integration between the medical and the dental team may be an important approach in the post-transplant maintenance routine.

Prevalence and distribution of serotype-specific genotypes of Aggregatibacter actinomycetemcomitans in chronic periodontitis Brazilian subjects

OBJECTIVE Previous studies have suggested that Aggregatibacter actinomycetemcomitans is involved in the aetiology of aggressive periodontitis as well as chronic periodontitis. In addition, some authors have also reported that serotype-specific antigens of A. actinomycetemcomitans determine the severity of disease. This study aimed to elucidate the prevalence of A. actinomycetemcomitans and the distribution of A. actinomycetemcomitans serotypes in Brazilian subjects with chronic periodontitis. DESIGN A total of 486 individuals were enrolled in this survey. All patients received clinical examinations that included periodontal pocket depth, clinical attachment loss, plaque, and gingival indexes. Subgingival samples were taken for microbial analysis. The genomic DNA of A. actinomycetemcomitans was provided by PCR. RESULTS Out of 486 subjects examined, A. actinomycetemcomitans was isolated in 85 (17.5%) individuals. Out of 85 positive samples, 68 were infected by at least 1 serotype, 7 by mixed infection, and 10 were non-serotyped. Serotypes d and f were not detected. Serotype c showed the highest prevalence (52.9%), followed by serotype a (31.8%). CONCLUSIONS Intragroup analysis revealed that, in slight/moderate periodontitis, serotypes c and a were significantly more prevalent than serotypes b and d-f; the prevalence of serotype c in severe periodontitis was significantly greater than that of serotypes a and b. Our data were similar in Asian and Eurasian populations.

Diminished Treatment Response of Periodontally Diseased Patients Infected with the JP2 Clone of Aggregatibacter (Actinobacillus) actinomycetemcomitans

ABSTRACT This longitudinal study evaluated the response to periodontal treatment by subjects infected with either JP2 (n = 25) or non-JP2 (n = 25) Aggregatibacter (Actinobacillus) actinomycetemcomitans. Participants were treated during the first 4 months by receiving (i) scaling and root planing, (ii) systemic antibiotic therapy, and (iii) periodontal surgery. Probing depth (PD), clinical attachment level (CAL), and gingival and plaque indices (GI and PI, respectively) were monitored at baseline and at 12 months, along with DNA-PCR-based subgingival detection of JP2 or non-JP2 A. actinomycetemcomitans. At baseline, PD, CAL, and GI scores were statistically higher in the JP2 strain-positive group than the non-JP2-strain-positive group. At 12 months, PD, CAL, and GI scores had decreased significantly for both groups, but the reduction rates of PD and CAL were higher in the non-JP2-strain-positive group. Among JP2-strain-positive patients in the baseline, patients who remained JP2 strain positive at 12 months showed significantly higher GIs than did the patients who had lost the detectable JP2 clone. Patients who remained JP2 strain positive at 12 months appeared to be more resistant to mechanical-chemical therapy than did those who were still non-JP2 strain positive, while the elimination of JP2 A. actinomycetemcomitans remarkably diminished gingival inflammation. Early identification and elimination of the JP2 clone of A. actinomycetemcomitans will enable practitioners to effectively predict the outcome of treatments applied to periodontal patients.

Selective serotonin reuptake inhibitors attenuate the antigen presentation from dendritic cells to effector T lymphocytes

Fluoxetine, one of the selective serotonin reuptake inhibitors (SSRIs), has been found to possess immune modulation effects, in addition to its antidepressant effects. However, it remains unclear whether SSRIs can suppress the antigen-presenting function of dendritic cells (DCs). Therefore, Fluoxetine was applied to a co-culture of Aggregatibacter actinomycetemcomitans (Aa)-reactive T cells (×Aa-T) isolated from Aa-immunized mice and DCs. This resulted in the suppressed proliferation of ×Aa-T stimulated with Aa-antigen presentation by DCs. Specifically, Fluoxetine increased the extracellular 5-hydroxytryptamine (5-HT) in the ×Aa-T/DC co-culture, whereas exogenously applied 5-HT promoted T-cell proliferation in the ×Aa-T/DC co-culture, indicating that Fluoxetine-mediated suppression of ×Aa-T/DC responses cannot be attributed to extracellular 5-HT. Instead, Fluoxetine remarkably suppressed the expression of costimulatory molecule ICOS-L on DCs. Fluoxetine also promoted a greater proportion of CD86(Low) immature DCs than CD86(High) mature DCs, while maintaining the expression levels of CD80, MHC-class-II and PD-L1. These results suggested that Fluoxetine suppressed the ability of DCs to present bacterial antigens to T cells, and the resulting T-cell proliferation, in a SERT/5-HT-independent manner and that diminished expression of ICOS-L on DCs and increase of CD86(Low) immature DCs caused by Fluoxetine might be partially associated with Fluoxetine-mediated suppression of DC/T-cell responses.

Aggregatibacter actinomycetemcomitans serotypes infections and periodontal conditions: a two-way assessment

This study investigated a large population of individuals positive for A. actinomycetemcomitans and performed a two way analysis assessing the relation between the different serotypes of the bacterium and periodontal conditions. The serotypes analysis (serotypes a, b, c, d, e, f) showed that out of the 204 selected individuals positive for A. actinomycetemcomitans, 152 were positive for a single serotype, 27 showed a variable mixed infection and 25 individuals were not positive for any of the serotypes tested. Serotypes a, b and c were largely found (98%), and serotype c was the most prevalent. Serotypes d, e, and f were either not detected or relatively rare. It was also verified that in non-periodontitis individuals, serotypes a and c were more prevalent (p < 0.05); in individuals with mild or moderate/severe chronic periodontitis serotype c was also more common (p < 0.05); and aggressive periodontitis subjects showed high prevalence of both serotypes b and c (p < 0.05). In conclusion, our study showed that serotype c was the most prevalent in both diseased and healthy subjects. Aggressive periodontitis subjects were not exclusively associated with A. actinomycetemcomitans serotype b. Non-typeable strains were either not detected or were relatively infrequent, and serotypes d and f were not detected in the examined Brazilian population.