No Association of Polymorphisms in Nav1.7 or Nerve Growth Factor Receptor Genes with Trigeminal Neuralgia.

OBJECTIVE: Trigeminal neuralgia is defined as a sudden severe shock-like pain within the distribution of the trigeminal nerve. Pain is a subjective experience that is influenced by gender, culture, environment, psychological traits, and genes. Sodium channels and nerve growth factor play important roles in the transmission of nociceptive signals and pain. The aim of this study was to investigate the occurrence of Nav1.7 sodium channel and nerve growth factor receptor TrkA gene polymorphisms (SCN9A/rs6746030 and NTRK1/rs633, respectively) in trigeminal neuralgia patients. METHODS: Ninety-six subjects from pain specialty centers in the southeastern region of Brazil were divided into 2 groups: 48 with classical trigeminal neuralgia diagnosis and 48 controls. Pain was evaluated using the visual analog scale and multidimensional McGill Pain Questionnaire. Genomic DNA was obtained from oral swabs in all individuals and was analyzed by real-time polymerase chain reaction. RESULTS: No association was observed between evaluated polymorphisms and trigeminal neuralgia. For allele analyses, patients and controls had similar frequencies for both genes. Genotype distribution or allele frequencies of polymorphisms analyzed here did not correlate to pain scores. CONCLUSIONS: Although no association of evaluated polymorphisms and trigeminal neuralgia diagnosis or pain severity was observed, our data do not exclude the possibility that other genotypes affecting the expression of Nav1.7 or TrkA are associated with the disease. Further studies should investigate distinct genetic polymorphisms and epigenetic factors that may be important in expression of these molecules.

Ações extensionistas em saúde bucal na rede pública de ensino de Belo Horizonte, MG, Brasil / Extension actions in oral health in the public school system of Belo Horizonte, MG, Brazil

Objetivo:A escola mostra-se como um ambiente favorável para a divulgação e compartilhamento de informações sobre saúde. Este estudo objetivou relatar as ações extensionistas promovidas pelo Projeto "Promoção de Saúde Bucal" em duas escolas públicas de Belo Horizonte/MG. Métodos:Um total de 105 escolares com idade entre 8 e 15 anos participaram do estudo. A equipe do projeto foi constituída por alunos e professores da UFMG. Foram realizadas três intervenções com informações educativas sobre saúde bucal. Os escolares responderam a um questionário para avaliar seus hábitos diários e conhecimentos sobre saúde bucal, antes e após as intervenções. Foram realizadas análises descritivas, testes de McNemar e de Wilcoxon (p < 0,05). Resultados:As intervenções foram capazes de melhorar o conhecimento e atitudes dos escolares sobre saúde bucal. Em relação à primeira avaliação, houve uma redução significativa na quantidade relatada de creme dental colocada na escova dentes (p < 0,001). Além disso, os escolares passaram a utilizar o fio dental com maior frequência, houve redução na frequência da ingestão de doces e menor interesse em utilizar piercings e aparelhos ortodônticos falsos. Conclusão:As atividades extensionistas resultaram em maior conhecimento dos escolares sobre saúde bucal e ressaltam a necessidade de continuidade das ações para que bons hábitos de saúde sejam sedimentados. (AU)

Aim:Schools have proven to be favorable environments for the dissemination and sharing of health information. This study aimed to report the extension actions promoted by the Project "Oral Health Promotion" in two public schools in Belo Horizonte/MG. Methods:A total of 105 students, 8 to 15 years of age, participated in the study. The project team consisted of students and professors from UFMG. Three interventions were carried out using educational information on oral health. The students answered a questionnaire to evaluate their daily habits and knowledge about oral health before and after the interventions. Descriptive analyzes, as well as McNemar and Wilcoxon tests, were performed (p < 0.05). Results:Interventions were able to improve students' knowledge and attitudes about oral health. In relation to the first assessment, there was a significant reduction in the reported amount of toothpaste placed on the toothbrush (p < 0.001). In addition, the schoolchildren began to use dental floss more frequently, there was a reduction in the frequency of the intake of candies and less interest in using piercings and false orthodontic appliances. Conclusion:The extension activities resulted in greater knowledge of the students about oral health and highlighted the need for continuous actions so that good health habits are solidified. (AU)

Associação entre metilação do DNA e periodontite crônica: revisão de literatura / Association between DNA methylation and chronic periodontitis: literature review

A periodontite crônica (PC) é uma doença bucal caracterizada pela presença de bactérias que promovem a inflamação dos tecidos de suporte e inserção dos dentes, como resultado de complexas interações entre patógenos periodontais e a resposta imune do hospedeiro. A PC é multifatorial e os fatores envolvidos com a regulação gênica podem interferir na predisposição ao aparecimento dos sinais e sintomas da doença. Neste contexto estão os mecanismos epigenéticos caracterizados por modificação na expressão dos genes sem afetar a sequência do DNA. As principais evidências de alterações epigenéticas na PC se relacionam à análise do perfil de metilação em genes relacionados à resposta imunoinflamatória. A metilação do DNA é um mecanismo epigenético caracterizado pela adição de um grupo metil no carbono 5' do anel de citosina, inibindo efetivamente a transcrição gênica. O objetivo do estudo foi revisar a literatura sobre a metilação do DNA na PC e avaliar sua associação com a patogênese da doença. Foi realizada uma busca na base de dados (Pubmed), sem restrição de ano e/ou idioma, utilizando os seguintes descritores: (Methylation [MeSh] OR Methylation OR DNA methylation [MeSh] OR DNA methylation) and (Chronic periodontitis [Mesh] OR Chronic periodontitis). Apesar dos estudos epigenéticos em doença periodontal ainda serem escassos, com diversos pontos a serem elucidados, os achados sugerem o envolvimento da metilação do DNA em genes da resposta imunoinflamatória na patogênese da PC. (AU)

Chronic periodontitis (CP) is an oral disease characterized by the presence of bacteria that promote inflammation of the supporting tissues of the teeth, as a result of complex interactions between periodontal pathogens and the host immune response. The CP is multifactorial and the factors involved in gene regulation may interfere with the predisposition on the appearance of the signs and symptoms of the disease. In this context it has been observed the epigenetic mechanism characterized by change ingene expression without affecting the sequence of DNA. The main evidence of epigenetic changes in CP are related to the analysis of the methylation profile in genes involved with the immune response. DNA methylation is an epigenetic mechanism characterized by the addition of a methyl group on the 5' carbon of the cytosine ring, effectively inhibiting the gene transcription. The aim of this study was to review the literature on DNA methylation in CP and evaluate its association with the pathogenesis of the disease. The search was performed in the database (Pubmed) without year or language restriction restriction, using the following key words: (Methylation [MeSh] OR Methylation OR DNA methylation [MeSh] OR DNA methylation) and (Chronic periodontitis [Mesh] OR Chronic periodontitis). Despite the epigenetic studies on periodontal disease are still scarce, with several points to be elucidated, the findings suggest the involvement of DNA methylation in immune response genes in the pathogenesis of CP (AU)

Expression, polymorphism and methylation pattern of interleukin-6 in periodontal tissues.

Periodontitis is considered an inflammatory disorder of bacterial etiology that results in periodontal tissue destruction, as a result of complex interactions between periodontal pathogens, host and immune response. Genetic and epigenetic mechanisms may modulate the individual response since it is able to influence the gene expression. The aim of this study was to evaluate the impact of -174 G/C polymorphism and the methylation status of the promoter region of IL-6 gene on the expression of IL-6 in gingival samples from individuals with chronic periodontitis. Gingival biopsies were collected from 21 patients with chronic periodontitis and 21 controls. Histologic sections stained by hematoxylin-eosin were used for histopathological evaluation. The IL-6 gene expression was assessed by quantitative real-time PCR. The polymorphism IL-6 -174 C/G was studied by polymerase chain reaction (PCR) amplification and restriction endonuclease digestion (HspII). Methylation-specific polymerase chain reaction was used to verify the DNA methylation pattern. The number of inflammatory cells in tissue fragments from individuals with chronic periodontitis was higher than in the control group and the inflammatory infiltrate was predominantly mononuclear. The expression of IL-6 was higher in the group with periodontitis. In polymorphism assay, no statistical difference in the distribution of genotypes and alleles in both groups were observed. The most of samples were partially methylated. No difference was observed in methylation pattern from two different regions of the IL-6 gene among groups. The high expression of IL-6 is an important factor related to chronic periodontitis, but was not associated with methylation status or the -174 (G/C) genetic polymorphism, suggesting that other mechanisms are involved in this gene transcription regulation.

Evaluation of IL17A expression and of IL17A, IL17F and IL23R gene polymorphisms in Brazilian individuals with periodontitis.

The IL23/Th17 axis plays an important role in the pathogenesis of cell-mediated tissue damage caused either by autoimmunity or immune responses against bacterial infection. Single nucleotide polymorphisms in the IL17A, IL17F and IL23R genes have been associated with several inflammatory diseases. However, these polymorphisms have not yet been studied in periodontitis. The aim of present study was to evaluate the expression of IL17A and occurrence of the IL17A (rs2275913), IL17F (rs763780) and IL23R (rs11209026) gene polymorphisms in different clinical forms or severity of periodontitis in a sample of Brazilian individuals. Peripheral blood was obtained from 30 non-smoker individuals and analyzed by flow cytometry to determine IL-17 expression. Genomic DNA was obtained from oral swabs in 180 individuals and analyzed by Real-time PCR. The study group was composed by individuals without periodontitis (control), with aggressive periodontitis (AP) and with chronic periodontitis (CP). Higher frequency of IL17A+CD4+ T cells was observed in control group. The A+ genotype from IL17A (rs2275913) was associated with lack of disease. No association was found considering the IL17F and IL23R polymorphisms. Our data suggest that IL17A and the presence of IL17A (rs2275913) A allele are associated with the absence of periodontal disease.

Hypomethylation of tumor suppressor genes in odontogenic myxoma.

Odontogenic myxoma (OM) is an ectomesenchymal benign odontogenic tumor characterized by spindle or stellate-shaped cells embedded in an abundant myxoid or mucoid extracellular matrix. DNA methylation is characterized by the addition of methyl groups in cytosines within CpG islands in the promoter gene. DNA methylation can decrease the expression of tumor suppressor genes and contribute to the development of neoplastic lesions. The aim of study was to evaluate the methylation pattern of the tumor suppressor genes P16 (CDKN2A), P21 (CDKN1A), P27 (CDKN1B), P53 (TP53) and RB1 in OM and dental pulp. Methylation was evaluated using methylation-specific polymerase chain reaction (PCR). The transcription was studied in some cases by using reverse transcription quantitative PCR. A higher frequency of unmethylated P27, P53, and RB1 samples was observed in the OM when compared with the dental pulp. OM expressed mRNA of all the genes evaluated. Considering all the samples together, the expression of Rb was higher in the unmethylated samples compared with the partially methylated samples. This investigation revealed hypomethylation of the genes P27, P53, and RB1 in OM. In addition, methylation of tumor suppressor genes was found to be an usual event in normal dental pulp.

Hypomethylation of tumor suppressor genes in odontogenic myxoma

Odontogenic myxoma (OM) is an ectomesenchymal benign odontogenic tumor characterized by spindle or stellate-shaped cells embedded in an abundant myxoid or mucoid extracellular matrix. DNA methylation is characterized by the addition of methyl groups in cytosines within CpG islands in the promoter gene. DNA methylation can decrease the expression of tumor suppressor genes and contribute to the development of neoplastic lesions. The aim of study was to evaluate the methylation pattern of the tumor suppressor genes P16 (CDKN2A), P21 (CDKN1A), P27 (CDKN1B), P53 (TP53) and RB1 in OM and dental pulp. Methylation was evaluated using methylation-specific polymerase chain reaction (PCR). The transcription was studied in some cases by using reverse transcription quantitative PCR. A higher frequency of unmethylated P27, P53, and RB1 samples was observed in the OM when compared with the dental pulp. OM expressed mRNA of all the genes evaluated. Considering all the samples together, the expression of Rb was higher in the unmethylated samples compared with the partially methylated samples. This investigation revealed hypomethylation of the genes P27, P53, and RB1 in OM. In addition, methylation of tumor suppressor genes was found to be an usual event in normal dental pulp.

O mixoma odontogênico (MO) é um tumor odontogênico benigno de origem mesenquimal caracterizado pela presença de células fusiformes ou estreladas dispostas em abundante matriz extracelular mucóide. A metilação do DNA é caracterizada pela adição de grupos metil em citosinas constituintes de ilhas CpG na região promotora do gene. A metilação pode diminuir a expressão de genes supressores de tumor e contribuir para o desenvolvimento de lesões neoplásicas. O objetivo deste trabalho foi avaliar o padrão de metilação nos genes P16 (CDKN2A), P21 (CDKN1A), P27 (CDKN1B), P53 (TP53), RB1 nos MO e na polpa dental. A metilação foi avaliada pela reação em cadeia da polimerase específica para a metilação. A transcrição dos genes foi estudada em alguns casos pela reação da transcriptase reversa (PCR quantitativa). Uma maior frequência de amostras não metiladas para os genes P27, P53 e RB1 foi observada nos MO quando comparados à polpa dental. Os MO expressaram RNAm de todos os genes avaliados. Considerando todas as amostras juntas, a expressão de Rb foi maior em amostras não metiladas comparadas as amostras parcialmente metiladas. Esta investigação mostrou a hipometilação dos genes P27, P53 e RB1 nos MO. Adicionalmente, a metilação nos genes supressores de tumor é um evento frequente em polpa dental normal.

Imunologia da retinocoroidite toxoplásmica / Immunology of the toxoplasmic retinochoroiditis

A infecção pelo Toxoplasma gondii é uma importante causa de doença ocular, tanto em indivíduos imunocomprometidos como em imunocompetentes. A patogênese da destruição retinocoroidiana associada a essa infecção ainda não está totalmente esclarecida. Nesta revisão, discute-se o papel do sistema imune no controle da infecção pelo Toxoplasma, especialmente, no olho.

Toxoplasma gondii infection is an important cause of ocular disease in both immunocompromised and immunocompetent subjects. The pathogenesis of retinochoroidal lesion associated with this infection is not fully understood. In this review, the role of the immune system in the control of Toxoplasma infection, especially in the eye, is discussed.

Effect of age on the association between p16CDKN2A methylation and DNMT3B polymorphism in head and neck carcinoma and patient survival.

De novo DNA methylation is a relevant epigenetic mechanism, which represses gene transcription and commonly inactivates tumor suppressor genes in carcinogenesis. A single nucleotide polymorphism of DNMT3B, C46359T (-149C-->T) was reported to modulate individual's susceptibility to cancer. We investigated the role of this polymorphic variant regarding the methylation status of the p16CDKN2A gene in young and older patients with head and neck squamous cell carcinoma (HNCC) matched by the TNM staging system, together with its impact on patients survival. The results showed that the presence of the allele T of the polymorphism DNMT3B (-149C-->T) was associated with advanced TNM staging and smoking habit, but no association was found between this polymorphisms and DNMT3B immunostaining. While p16CDKN2A methylation was significantly associated with smoking habit in older patients, this parameter was associated with family history of cancer in young patients. Moreover, in older patients the absence of p16CDKN2A promoter methylation had a negative impact on survival. In conclusion, nucleotide polymorphism of DNMT3B is not associated with methylation of p16CDKN2A gene in HNSCC. The association of p16CDKN2A gene methylation with smoking, family history of cancer and survival is dependent on age.

Gingival overgrowth in cyclosporine, tacrolimus, or sirolimus-based immunosuppressive regimens and the single nucleotide IL-6 (-174 G/C) gene polymorphism.

OBJECTIVE: Interleukin-6 (IL-6) may be involved in drug-induced gingival overgrowth (GO). The present study was conducted to assess the association between IL-6 (-174 G/C) gene polymorphism and GO in renal transplant recipients under cyclosporine (CsA), tacrolimus (Tcr), or sirolimus (Sir)-based regimens. METHODS: Within an eligible population, 45 unrelated subjects were selected for each CsA, Tcr, and Sir group, totaling a sample of 135 subjects. GO was visually assessed and subjects were assigned as controls (non-responders) or cases (responders) in a post hoc definition. IL-6 gene polymorphism was assessed using the polymerase chain reaction amplification and digestion. The distribution of genotypes and allele frequencies in responders and non-responders were compared using the Chi-squared test. RESULTS: The number of responders was 27 (60.0%), 13 (28.9%), and 7 (15.6%) in the CsA, Tcr, and Sir groups, respectively. No differences could be observed at frequencies of -174GG, -174CG, and -174CC genotypes when comparing responders to non-responders in the CsA, Tcr, and Sir groups. Similar to genotypes, allele frequencies showed no differences between responders and non-responders in all groups. CONCLUSIONS: No association between IL-6 (-174 G/C) gene polymorphism and gingival overgrowth was observed in renal transplant recipients under CsA, Tcr, or Sir-based immunosuppressive maintenance regimens.

Methylation frequencies of cell-cycle associated genes in epithelial odontogenic tumours.

OBJECTIVE: The benign epithelial odontogenic tumours constitute a group of lesions derived from epithelial elements of the tooth-forming apparatus. This group includes lesions of different biological behaviour, such as ameloblastoma, calcifying cystic odontogenic tumour (CCOT) and adenomatoid odontogenic tumour (AOT). The pathogenesis of these neoplasms remains uncertain and the occurrence of methylation in cell-cycle related genes may be involved in their development. The aim of this study was to investigate the methylation status of P16, P21, P27, P53 and RB1 genes in epithelial odontogenic tumours. DESIGN: Methylation-specific polymerase chain reaction (MSP) was used to evaluate the presence of methylation in 13 samples of ameloblastoma, six samples of CCOT, three samples of AOT and 14 samples of dental follicles, included as control. RESULTS: Our results showed a distinct methylation profile in each group. In ameloblastoma, the highest methylated genes were P16 and P21, while in CCOT the P21 and RB1 genes were the most commonly methylated genes. Only the P16 and P21 genes were methylated in the AOT samples. In the dental follicle samples, P16, P27 and RB1 genes were commonly methylated. A high percentage of the odontogenic tumours analysed showed methylation of the P21 gene, in contrast to dental follicles. CONCLUSIONS: Epithelial odontogenic tumours show a distinct methylation profile in cell-cycle associated genes. In addition to this, the current findings show that epigenetic alterations are common events in epithelial odontogenic tumours.

Methylation of P16, P21, P27, RB1 and P53 genes in odontogenic keratocysts.

BACKGROUND: Odontogenic keratocyst (OKC) is a benign neoplasm with an aggressive clinical behavior and a high recurrence rate. Although epigenetic alterations have been reported in different tumors, these events were not investigated in OKC yet. The aim of this study was to investigate the presence of methylation in P16, P21, P27, P53 and RB1 genes in OKC tumors. METHODS: Methylation-specific polymerase chain reaction (MSP) was used to evaluate the presence of methylation in 10 samples of OKCs, 10 samples of dental follicles and six samples of normal mucosa. RESULTS: The methylation status of the P16 gene was similar among the three groups. In P21 gene, 30% of OKCs were methylated while no methylation could be detected in the other groups. High frequency of P27 methylation (90%) was observed in dental follicles, however, some OKC lesions (10%) and normal mucosa samples (33%) were also methylated. Concerning the RB1 gene, positive results were detected only in dental follicles (40%). No positive result was observed considering P53 gene. CONCLUSIONS: Our data show methylation of the promoter of P21 gene in OKCs. In addition, methylation of the P27 and RB1 genes are commonly found in dental follicles. Further studies are necessary to determine the functional relevance of these alterations.

PTCH1 isoforms in odontogenic keratocysts.

Odontogenic keratocyst (OKC) is an aggressive benign odontogenic neoplasm associated with PTCH1 alteration. PTCH1 has several isoforms generated by use of different first exon (1b, 1d and 1e). These isoforms code for proteins with different functions, expression profiles and transcriptional regulation. The aim of the present study was to investigate the expression of PTCH1 first exons in OKC tumors to shed light on scenery whereby PTCH1 coordinates OKC tumorigenesis. Forty OKC, including 12 sporadic and 28 associated with Nevoid Basal Cell Carcinoma Syndrome (NBCCS), were included in the study. The variants 1b, 1d and 1e were investigated by RT-PCR. The exon 1b was detected in 90% of OKC and none of the dental follicle (control). Most of the OKC, sporadic and syndromic, and all of the samples of dental follicles demonstrated the expression of 1d mRNA. All primary OKC had 1b mRNA while 4 (24%) lesions marsupialized lost 1b expression. In addition, the pattern of exon 1 expression observed in oral mucosa adjacent to the OKC was similar to the OKC tumor. In conclusion, this report showed overactivity of Hedgehog (HH) pathway in OKC lesion and at adjacent oral mucosa. We also demonstrated that marsupialization could alter PTCH1 variants profiling in some OKC cases.

Imunogenética das uveítes / Imunogenetics in the uveítes

Citocinas são moléculas envolvidas na comunicação intercelular nas respostas inflamatória e imune, desempenhando papel relevante nas uveítes. Polimorfismos dos genes responsáveis pela produção de determinadas citocinas têm sido relacionados com a ocorrência e a gravidade de algumas uveítes. Portanto, o presente trabalho tem como objetivo relatar essas possíveis associações, salientando o aspecto individual genético no prognóstico das uveítes.

Cytokines are molecules involved in intercellular communication in immune and inflammatory responses, playing an important role in uveitis. Genetic polymorphisms responsible for the production of certain cytokines have been associated with the occurrence and the severity of uveitis. Therefore, the present study has the purpose of describing these possible associations, pointing out the individual genetic background in the prognosis of uveitis.