Fábio Renato Manzolli Leite

Signaling pathways associated with the expression of inflammatory mediators activated during the course of two models of experimental periodontitis

AIMS Evaluate the signaling pathways associated with inflammatory mediators activated in two models of experimental periodontitis. MAIN METHODS Two models were used: lipopolysaccharide (LPS) injections and ligature placement. Wistar rats were used and 30 microg LPS from Escherichia coli was injected twice a week into the palatal aspect of the upper molars. Ligatures were placed around lower first molars. A control group received injections of PBS on the palatal gingivae whereas no ligatures were placed on the lower molars. Samples were collected 5, 15 and 30 days and processed for analysis by Western blotting and stereometry. KEY FINDINGS The ligature model was associated with rapid and transient activation of extracellular-regulated kinases (ERK) and p38 mitogen-activated protein kinase (MAPK) as well as of nuclear factor kappa B (NF-kappaB). Activation of these signaling pathways on the LPS model was delayed but sustained throughout the 30-day experimental period. Inflammatory changes induced by both models were similar; however there was a significant reduction on inflammation degree on the ligature model, which paralleled the decrease observed on the activation of the signaling pathways. Activation of signal transducer and activator of transcription (STAT)-3 by phosphorylation of Tyrosine residues and of STAT-5 was observed only on the ligature model. SIGNIFICANCE Regulation of gene expression results from the activation of signaling pathways initiated by receptor-ligand binding of external antigens and also of cytokines produced by the host immune system. Understanding the signaling pathways relevant for a given condition may provide information useful for novel therapeutic approaches.

Relevance of the Myeloid Differentiation Factor 88 (MyD88) on RANKL, OPG, and Nod Expressions Induced by TLR and IL-1R Signaling in Bone Marrow Stromal Cells

The myeloid differentiation factor 88 (MyD88) plays a pivotal role in Toll-like receptor (TLR)- and interleukin-1 receptor (IL-1R)-induced osteoclastogenesis. We examined the role of MyD88 on p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) activation and nucleotide-binding oligomerization domain (Nod) induction by lipopolysaccharide (LPS) and IL-1 beta, and their effect on receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) production in bone marrow stromal cell (BMSC). RANKL, Nod1, Nod2, NF-κB, and p38 protein levels were determined by Western blot. Nod2 was stimulated with muramyl dipeptide (MDP) prior to TLR4 stimulation with LPS. MyD88 deficiency markedly inhibited RANKL expression after LPS stimulation and increased OPG messenger RNA (mRNA) production. Also, MyD88 was necessary for NF-κB and p38 MAPK activation. MDP alone did not induce RANKL and OPG expressions; however, when combined with LPS, their expressions were significantly increased (p < 0.05). Our results support that MyD88 signaling has a pivotal role in osteoclastogenesis thought NF-κB and p38 activation. Nod2 and especially Nod1 levels were influenced by MyD88.

Blood cell attachment to root surfaces treated with EDTA gel

Root debridement generates a smear layer which contains microorganisms and toxins that could interfere in periodontal healing. For this reason, different substances have been used to remove it and to expose collagen fibers at the tooth surface. Blood element adhesion to demineralized roots and clot stabilization by collagen fibers are extremely important for the success of periodontal surgery. The aim of this study was to evaluate the different patterns of blood element adsorption and adhesion to root surfaces only irrigated with distilled water and after application of a manipulated or an industrialized EDTA gel. Thirty samples were planed, equally divided into three groups and treated with distilled water (control), a manipulated EDTA gel or an industrialized one. Immediately after, samples were exposed to fresh blood and prepared for scanning electron microscopy. Untreated planed dentin presented the best results with blood cells entrapped in a thick web of fibrin. In the manipulated EDTA group, the web of fibrin was thick with sparse blood elements. The worst result was seen with the industrialized EDTA group, in which no blood elements could be seen. Statistical difference was obtained between control and industrialized EDTA groups. Surfaces only irrigated presented the most organized fibrin network and cell entrapment.

Can Peri-Implant Crevicular Fluid Assist in the Diagnosis of Peri-Implantitis? A Systematic Review and Meta-Analysis

BACKGROUND A broader understanding of the immune inflammatory profile of peri-implant diseases could be helpful in the development of host-targeted preventive and therapeutic strategies. The aim of this study is to answer two clinical questions: 1) whether patients with peri-implantitis (PP) present higher prevalence of any specific inflammatory cytokine in peri-implant crevicular fluid (PICF) compared with healthy patients; and 2) whether local inflammation measured in PICF can be used as a predictor for incipient PP. METHODS A systematic review of the literature on the most common cytokines released in PICF in healthy and PP-affected sites was conducted from 1996 up to and including October 2013 using predefined search strategies. Cross-sectional and prospective longitudinal studies were considered. Meta-analyses were done separately for healthy, mucositis (MU), and PP outcomes. RESULTS Interleukin (IL)-1β was the most studied cytokine (n = 12), followed by tumor necrosis factor (TNF)-α (n = 10). Other cytokines were also linked to PP, such as IL-4, IL-6, IL-8, IL-10, IL-12, and IL-17. Statistical differences were revealed when IL-1β release was compared between healthy implant sites and PP (P = 0.001) or MU sites (P = 0.002), respectively; when PP and MU were compared, no statistical differences could be detected (P = 0.80). For TNF-α release, significant differences were found between healthy and PP implants (P = 0.02). CONCLUSIONS PICF containing inflammatory mediators, such as IL-1β and TNF-α, can be used as additional criteria for a more robust diagnosis of peri-implant infection. Additionally, once the inflammatory process is installed, no differences were found between peri-implant MU and PP.

Blood cell attachment to root surfaces treated with EDTA gel.

Root debridement generates a smear layer which contains microorganisms and toxins that could interfere in periodontal healing. For this reason, different substances have been used to remove it and to expose collagen fibers at the tooth surface. Blood element adhesion to demineralized roots and clot stabilization by collagen fibers are extremely important for the success of periodontal surgery. The aim of this study was to evaluate the different patterns of blood element adsorption and adhesion to root surfaces only irrigated with distilled water and after application of a manipulated or an industrialized EDTA gel. Thirty samples were planed, equally divided into three groups and treated with distilled water (control), a manipulated EDTA gel or an industrialized one. Immediately after, samples were exposed to fresh blood and prepared for scanning electron microscopy. Untreated planed dentin presented the best results with blood cells entrapped in a thick web of fibrin. In the manipulated EDTA group, the web of fibrin was thick with sparse blood elements. The worst result was seen with the industrialized EDTA group, in which no blood elements could be seen. Statistical difference was obtained between control and industrialized EDTA groups. Surfaces only irrigated presented the most organized fibrin network and cell entrapment.

Influence of concentration, time and method of application of citric acid and sodium citrate in root conditioning

Objective The aim of this study was to establish the parameters of concentration, time and mode of application of citric acid and sodium citrate in relation to root conditioning. Material and Methods A total of 495 samples were obtained and equally distributed among 11 groups (5 for testing different concentrations of citric acid, 5 for testing different concentrations of sodium citrate and 1 control group). After laboratorial processing, the samples were analyzed under scanning electron microscopy. A previously calibrated and blind examiner evaluated micrographs of the samples. Non-parametric statistical analysis was performed to analyze the data obtained. Results Brushing 25% citric acid for 3 min, promoted greater exposure of collagen fibers in comparison with the brushing of 1% citric acid for 1 minute and its topical application at 1% for 3 min. Sodium citrate exposed collagen fibers in a few number of samples. Conclusion Despite the lack of statistical significance, better results for collagen exposure were obtained with brushing application of 25% citric acid for 3 min than with other application parameter. Sodium citrate produced a few number of samples with collagen exposure, so it is not indicated for root conditioning.

(7-Chloroquinolin-4-yl)arylhydrazones: Candida albicans enzymatic repression and cytotoxicity evaluation, Part 2

Abstract Objective: This work describes the anti-enzymatic activity of (7-chloroquinolin-4-yl)arylhydrazones against Candida albicans and examines their cytotoxicity. Material and methods: Ten C. albicans strains [nine isolates and one azole-resistant standard strain (ATCC 62342)] were used to assess the anti-enzymatic activity. Fifteen compounds at sub-antifungal concentrations ranging from 12.5 to 100 µg/ml were assessed after a 30-min exposure. The strains were seeded onto petri dishes with selective agar media for aspartyl proteases (Saps) and phospholipases (PLs). Enzymatic inhibition was measured by the reduction of the precipitation zone (Pz) against untreated strains (positive control). A colorimetric MTT assay was used with 3T3/NIH mouse fibroblasts to evaluate cytotoxicity. Cells were exposed to 15 compounds in concentrations from 6.25 to 100 µg/ml for 24 and 48 h. Results: Four hydrazones showed enzymatic repression values over 40% to Pl and three over 20% to Saps. The cell viability was over 50% at hydrazone concentrations of 25–100 µg/ml. Conclusion: These results revealed that select (7-chloroquinolin-4-yl)arylhydrazones may be potential antifungal agents for the control of C. albicans infections.

A scanning electron microscopy study of root surface smear layer removal after topical application of EDTA plus a detergent

The aim of the present study was to compare root surface smear layer removal following topical application of EDTA and EDTA-T (Texapon). Extracted human teeth had their cementum removed and were mechanically scaled. A total of 220 root specimens were obtained and were randomly assigned to the following groups: I-saline solution (control), II-EDTA; III-EDTA-T. Groups II and III specimens were assigned to different EDTA gel concentrations: 5%, 10%, 15%, 20% and 24%. Smear layer removal score was assessed for each specimen by scanning electron microscopy. The results demonstrated that EDTA and EDTA-T gel led to a higher root surface smear layer removal when compared to the control group. The 5% EDTA gel also showed a higher smear layer removal than the 15%, 20% and 24% EDTA gels (p<0.05). No difference could be found between the different concentrations of EDTA-T gels tested (p>0.05). EDTA gels had statistically significantly lower smear layer scores than the EDTA-T gels for the 5% and 10% concentrations. The results suggested that topical application of EDTA or EDTA-T gel led to significant smear layer removal of the mechanically treated root surfaces. The addition of a detergent to the EDTA gel formula did not improve smear layer removal of the root surface.

Non-white people have a greater risk for maxillofacial trauma: findings from a 24-month retrospective study in Brazil

Aim: To identify the predominant causes and types of maxillofacial trauma in Brazil. Methods: Reports of corporal trauma (7,536) between 2009-2010 in the Brazilian Institute of Forensic Medicine were analyzed as to the presence of maxillofacial traumas. Victims’ demographic and trauma characteristics were recorded. Results: Data were submitted to chi-square test and to multivariate Poisson regression. 778 reports referred maxillofacial trauma. Most victims were men (50.8%) around 27.6 years. Main causes were physical aggression (88.1%) and traffic accidents (6.7%). The most affected extraoral area was the middle third (60.7%). Risk for trauma in the middle third was significantly higher among patients aged 61-75 (RR 1.32), and non-white patients (black-skinned RR 1.21; brown-skinned RR 1.18); while falls were associated with trauma in the lower third (RR1.79). Conclusions: Violence was the main cause of maxillofacial trauma. Prevention of interpersonal violence may be a key element to prevent maxillofacial trauma.