Objetivo: o presente estudo prospectivo avaliou a presença de microrganismos periodontopatogênicos, os níveis salivares de arginase e de HBD-2 em indivíduos com gengivite e periodontite tendo como controle indivíduos periodontalmente saudáveis, correlacionando-os aos respectivos parâmetros clínicos. Também foi avaliada expressão gênica do PAR2 crevicular em indivíduos saudáveis e com periodontite. Método: Inicialmente, foram avaliados 89 indivíduos sem doenças sistêmicas, nunca fumantes, sendo 31 saudáveis (média de idade 25,06 5,97), 27 com gengivite (média de idade 33,22 12,09) e 31 com periodontite (média de idade 52,16 11,54), todos submetidos à terapia periodontal não cirúrgica. Coleta salivar para avaliação dos níveis de arginase (quantificada por meio de espectrofotometria) foi realizada no início do tratamento em todos os indivíduos, e naqueles com gengivite e periodontite respectivamente em 30 e 50 dias pós-tratamento. Avaliação clínica de profundidade de sondagem, perda de inserção clínica e índices de placa e gengival e microbiana (Campylobacter rectus, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tanerella forsythia, Treponema denticola e Prevotella intermedia) foram também avaliados nos mesmos tempos. Dentre os 89 indivíduos, amostras do fluido gengival foram coletadas em 10 indivíduos saudáveis e 10 com periodontite para mensuração da atividade do PAR2 crevicular por meio de RT-PCR. Como esta relação foi positiva, foi verificada a quantidade de HBD-2 salivar por meio de ELISA de todos os 89 indivíduos e sua relação com os parâmetros clínicos e microbiológicos. A significância de todas as relações e quantificações foi analisada por meio de testes estatísticos apropriados. Resultados: foi observada uma melhora estatisticamente significativa dos parâmetros clínicos e microbianos após o tratamento periodontal. A arginase salivar estava significativamente mais elevada nos indivíduos com periodontite em relação àqueles com gengivite, e nestes em relação aos saudáveis. O tratamento periodontal promoveu melhora dos indivíduos doentes, cujos parâmetros avaliados tornaram-se estatisticamente semelhantes aos dos saudáveis. Houve maior atividade do PAR2 nos 10 indivíduos com periodontite em relação aos saudáveis e, após o tratamento, houve uma redução estatisticamente significativa deste parâmetro. Por fim, foram observados níveis estatisticamente mais elevados de HBD-2 salivar nos indivíduos com periodontite comparados àqueles com gengivite e aos saudáveis. Não foi possível observar uma correlação entre HBD-2 salivar e os microrganismos analisados. Conclusões: com base nos resultados observados, podemos concluir que: a arginase salivar está significativamente aumentada nos indivíduos periodontalmente comprometidos em relação aos saudáveis; o tratamento periodontal promoveu melhora dos indivíduos doentes em relação aos parâmetros avaliados; indivíduos com periodontite têm maior expressão gênica do PAR2 do que aqueles saudáveis e o tratamento tornou esta expressão semelhante nos dois grupos; indivíduos com periodontite têm níveis estatisticamente mais significativos de HBD-2 salivar do que aqueles saudáveis e aqueles com gengivite; a saliva parece ser uma ferramenta útil para o diagnóstico periodontal e para o monitoramento da eficácia do tratamento periodontal. / Objectives: This prospective study evaluated the presence of periodontopathogenics microorganisms, as it also examined the salivary levels of arginase and HBD-2 from subjects with gingivitis and periodontitis and periodontally healthy subjects as controls, correlating them to relevant clinical parameters. The gene expression of PAR2 crevicular in healthy subjects and periodontitis was also assessed. Methods: Initially, 89 individuals without systemic diseases, who were never smokers, were evaluated. Out of the 89, 31 were healthy subjects (average age 25.06 5.97), 27 have gingivitis (average age 33.22 12.09) and 31 were with periodontitis (average age 52.16 11.54), all underwent nonsurgical periodontal therapy. Saliva was collected for assessing levels of arginase at baseline in all subjects (quantified by spectrophotometry), and repeated on those with gingivitis and periodontitis respectively at 30 and 50 days post treatment. Clinical evaluation of probing depth, clinical attachment loss, both plaque and gingival index as well as microbial evaluation (Campylobacter rectus, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tanerella forsythia, Prevotella intermedia and Treponema denticola) were also assessed at the same time. Among the 89 individuals, gingival fluid samples were collected from 10 healthy ones and from 10 with periodontitis to measure crevicular PAR2 activity by RT-PCR. As the results came out positive, the amount of HBD-2 salivary was tested by ELISA for all 89 subjects assessing its relationship with clinical and microbiological parameters. The significance of all relationships and quantifications were analyzed using appropriate statistical tests. Results: we observed a statistically significant improvement of clinical and microbial parameters after periodontal treatment. Salivary arginase was significantly higher in subjects with periodontitis than in those with gingivitis, and those with gingivitis had higher results than the healthy ones. Periodontal treatment promoted improvement of the non-healthy individuals whose parameters became statistically similar to the healthy ones. There was a greater PAR2 activity in 10 individuals with periodontal disease compared to healthy ones, and after treatment the results showed a statistically significant reduction in this parameter. Finally, we observed statistically higher levels of salivary HBD-2 in individuals with periodontitis compared to both those with gingivitis and those individuals in the healthy group. It has not been possible to observe a correlation between HBD-2 and salivary microorganisms analyzed. Conclusion: Based on the observed results, we can conclude that salivary arginase is significantly increased in periodontally compromised individuals relative to the healthy ones; periodontal treatment promoted improvement of individuals in relation to the assessed parameters; individuals with periodontitis have higher gene expression of PAR2 than those healthy and the periodontal treatment brought similar results to both groups; individuals with periodontitis have statistically more significant levels of salivary HBD-2 than those with healthy gums and gingivitis; and, finally, saliva, besides being useful for periodontal diagnosis, appears to be also helpful for monitoring efficacy of periodontal treatment.

Doctor of Philosophy / Department of Human Nutrition / Tonatiuh Melgarejo / Background and Objective: Crohn’s disease (CD) patients express low levels of host defense peptides (HDPs) especially β-defensins, which may compromise intestinal barrier function. Antibiotic treatment for bacterial infections in CD is limited and rarely curative, making it necessary to find alternative therapeutic approaches. We therefore investigated to what extent an essential amino acid; L-isoleucine (L-ILE) might induce the expression of human β-defensins (HBDs) in colonic epithelial cells as an alternative approach to help patients with CD. Antimicrobial activity of HBD2 was also assessed against four bacterial isolates which can cause secondary infections in CD. Methods: HTB-37 Caco-2 cells were stimulated with L-ILE at a concentration of 0 - 500µg/ml for 6 hours. Total RNA was extracted using RNeasy Micro Kit (QIAGEN). Reverse transcription was carried out with Superscript ®III First-Strand Synthesis System. The cDNA was amplified using specific primers for HBD1-3. Antimicrobial activity of HBD2 was determined using the broth dilution assay. Results: HBD1 was constitutively expressed under all conditions. HBD2 was expressed in HTB-37 cells after stimulation with L-ILE. Below 25µg/ml L- ILE stimulation, no expression of HBD2 was observed. HBD2 exhibited antimicrobial activity against bacterial isolates tested, with a MIC of 32, 64 and 128 µg/ml for both strains of E. coli, S. aureus and P. aeruginosa respectively. Conclusions: Our results indicate that L-ILE stimulation of HTB-37 Caco-2 cells can induce HBD2 expression. Data collected from our in vitro studies might have major implications for modifying the intestinal microbiota towards a healthier state in CD patients. Promoting the expression of HBD2 by colonic cells may lead to a lower rate of infection in these patients. Future in vivo studies are warranted to determine the potential clinical use of intra colonic administration of L-ILE in CD patients. The observed antimicrobial activity of HBD2 against bacterial isolates provides evidence that it is a crucial component of mucosal epithelial defense against infections which can complicate disease symptoms in CD.