Bruna Rafaela Martins dos Santos

Immunohistochemical expression of E-cadherin and β-catenin in ameloblastomas and tooth germs

OBJECTIVE The aim was to analyze the expression of E-cadherin and beta-catenin in ameloblastomas and tooth germs to determine their roles in cell differentiation processes and invasiveness compared with odontogenesis. STUDY DESIGN Twenty-one ameloblastoma cases (16 solid and 5 unicystic tumors) and 5 tooth germs were submitted to the immunohistochemical detection of E-cadherin and beta-catenin. Immunoreactivity was evaluated using descriptive and semiquantitative analysis, investigating the location and intensity of staining. The Fisher exact test was performed, and P values of <.05 were considered to indicate statistical significance. RESULTS There was no statistically significant difference in the expression of E-cadherin and beta-catenin between solid and unicystic ameloblastomas (P = .59; P = .63; respectively). The same was found when comparing solid and unicystic ameloblastomas with the tooth germs for both E-cadherin (P = .53; P = .44; respectively) and beta-catenin (P = .12; P = .16; respectively). Nuclear staining of beta-catenin was observed in only 4 cases (3 solid and 1 unicystic tumor). CONCLUSION The results showed no differences in the expression of E-cadherin or beta-catenin between tooth germs and solid and unicystic ameloblastomas. The expression of these molecules seems mainly to be related to the process of cell differentiation.

Immunoexpression of HIF-1α and VEGF in Periodontal Disease and Healthy Gingival Tissues

Hypoxia-inducible factor 1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) are proteins that stimulate the proliferation and migration of endothelial cells. These proteins have been described in many pathologic and inflammatory conditions, but their involvement in the development of periodontitis has not been thoroughly investigated. This study compared the immunohistochemical expression of these proteins, involved in angiogenesis and hypoxia, by immunostained inflammatory and endothelial cells in periodontal disease and healthy gingival tissues. Gingival tissue samples were divided as follows: 30 samples with chronic periodontitis, 30 with chronic gingivitis, and 30 of healthy gingiva. Results were analyzed statistically by the Kruskal-Wallis, Mann-Whitney and Spearman correlation tests (p=0.01). Inflammatory and endothelial cells were found to express these proteins. Periodontitis showed median percentage of HIF-1α-positive cells of 39.6%, 22.0% in cases of gingivitis and 0.9% in the healthy gingiva group (p=0.001). For VEGF, median percentage of immunopositive cells was 68.7% for periodontitis, 66.1% in cases for gingivitis, and 19.2% for healthy gingival specimens (p<0.001). Significant correlation between VEGF and HIF-1α was also observed in healthy gingiva (p<0.001).The increased expression of HIF-1α and VEGF in periodontitis, compared to gingivitis and healthy gingiva, suggests possible activation of the HIF-1α pathway in advanced periodontal disease. The correlation between HIF-1α and VEGF expression in healthy gingiva suggests a physiological function for these proteins in conditions of homeostasis. In periodontal disease, HIF-1α and VEGF expression may be regulated by other factors, in addition to hypoxia, such as bacterial endotoxins and inflammatory cytokines.

Immunohistochemical expression of matrix metalloproteinases 1, 2, 7, 9, and 26 in the calcifying cystic odontogenic tumor

OBJECTIVE The aim was to evaluate immunoexpression of matrix metalloproteinases (MMPs) 1, 2, 7, 9, and 26 in calcifying cystic odontogenic tumor (CCOT). STUDY DESIGN Ten cases of CCOT were assessed by immunohistochemical expression of MMPs 1, 2, 7, 9, and 26 in the parenchyma and stroma. Metalloproteinase immunoexpressions and their distribution pattern were semiquantitatively scored. RESULTS MMPs were expressed in the parenchyma and stroma in all cases of CCOT. Regarding the percentage of immunostained parenchymal cells, MMPs 1, 7, and 9 showed score 2 in 100% of cases. For MMP-2, there was a predominance of score 0 (90%), whereas for MMP-26 immunostaining was varied. CONCLUSIONS The staining of these metalloproteinases, with the exception of MMP-2, suggests their contribution to tumor growth and expansion. The presence of these metalloproteinases in stromal cells reveals the active participation of these cells in the degradation of the extracellular matrix, contributing to the growth of the tumor studied.

Estudo epidemiológico das doenças dermatológicas imunologicamente mediadas na cavidade oral

BACKGROUND: Immune-mediated skin diseases encompass a variety of pathologies that present in different forms in the body. OBJECTIVE: The objective of this study was to establish the prevalence of the principal immune-mediated skin diseases affecting the oral cavity. METHODS: A total of 10,292 histopathology reports stored in the archives of the Anatomical Pathology Laboratory, Department of Oral Pathology, Federal University of Rio Grande do Norte, covering the period from 1988 to 2009, were evaluated. For the cases diagnosed with some type of disease relevant to the study, clinical data such as the gender, age and ethnicity of the patient, the anatomical site of the disease and its symptomatology were collected. RESULTS: Of all the cases registered at the above-mentioned service, 82 (0.8%) corresponded to immune-media ted skin diseases with symptoms affecting the oral cavity. The diseases found in this study were: oral lichen planus, pemphigus vulgaris and benign mucous membrane pemphigoid. Oral lichen planus was the most common lesion, comprising 68.05% of the cases analyzed. Of these cases, 64.3% were women and the cheek mucosa was the anatomical site most commonly affected (46.8%). CONCLUSION: Immune-mediated skin diseases affecting the oral cavity continue to be rare, the prevalence found in this study being similar to that reported for the majority of regions worldwide. Nevertheless, early diagnosis is indispensable in the treatment of these diseases, bearing in mind that systemic involvement is possible in these patients.

Prevalence of Subgingival Staphylococcus at Periodontally Healthy and Diseased Sites

Staphylococci are considered members of the transient oral microbiota and are seldom isolated from the oral cavity. The aim of this study was to establish the prevalence of subgingival staphylococci in healthy and periodontal disease sites. Sterile endodontic paper points were used to isolate subgingival staphylococci in periodontally healthy and periodontally diseased sites in 30 adult subjects (n=540 sites). Staphylococcus spp were identified by an automated method and confirmed by conventional biochemical tests. All the samples were identified as coagulase-negative staphylococci. The results were analyzed using Mann-Whitney U, chi-square and Fishers exact test at 5% significance level. A total of 86.7% of the subjects harbored these microorganisms in 11.7% of their periodontal sites. The most frequently isolated species was S. auricularis, which was isolated from 31.4% of the periodontal sites, followed by S. epidermidis, isolated from 21.4% of them. There was no statistically significant difference between the frequencies of these species isolated either from the healthy and the diseased sites (p>0.153). Although staphylococci are present in the subgingival environment and contribute to the pathogenic synergism involved in periodontal diseases, the results suggest that they do not participate directly in the pathogenesis of these diseases.