The invasive pathways, InlA- and InB-mediated uptake and M cell transcytosis, that Listeria monocytogenes uses to invade the intestine have mainly been studied using infection models that do not truly replicate what occurs during a natural infection. Recently, our lab has developed an oral infection model that is more physiolocally relevant to what occurs during food borne listeriosis. We have sought to evaluate the relative roles of the previously defined invasive pathways, in our oral model of infection. We have done this by utilizing an InlAmCG Lm strain that is able to bind murine E-cadherin, knockout Lm strains, ΔinlA Lm, and ΔinlAΔinlB Lm. We also took advantage of a knockout mice strain CD137-/-that has M cells that are deficient in M cell transcytosis. We were able to show that these invasive pathways are relevant in our oral infection model, that M cell transcytosis is a compensatory pathway for InlA-mediated uptake, and that there might be another mechanism that L. monocytogenes uses to invade the intestines. To confirm this, it is necessary though that the M cell transcytosis deficiency be confirmed in the CD137-/- mice.

Doentes que apresentam comprometimento cognitivo, como a doença de Alzheimer (DA), podem apresentar maior prevalência de infecções bucais. Entre elas, a periodontite crônica é uma infecção frequente associada ao aumento do nível sérico de marcadores inflamatórios, e recentemente tem sido apontada como um fator que pode relacionar-se à progressão da DA através de seus mecanismos sistêmicos. O objetivo deste trabalho foi verificar a prevalência de infecções bucais e os níveis séricos de IL-1beta, TNF- alfa e IL-6 em doentes com DA, comprometimento cognitivo leve (CCL) e idosos não-demenciados. Foram avaliados 65 idosos (25 com DA, 19 com CCL e 21 saudáveis). A avaliação incluiu o Mini Exame do Estado Mental, Questionário de Atividades Funcionais (Pfeffer), Avaliação Periodontal, índice CPOD, Questionário de Avaliação Clínica Orofacial (EDOF-HC) e avaliação de concentração sérica de IL-1beta, TNF-alfa e IL-6. Os doentes com DA e CCL apresentaram maior quantidade de dentes ausentes e por um período maior de tempo do que os idosos saudáveis (P= 0.038) e a doença periodontal (DP) foi a causa principal das perdas dentárias (P= 0.035). Os doentes apresentaram maior prevalência de candidose do que os controles (P= 0.05). As análises de correlação demonstraram que quanto maior a concentração de IL-6, pior a funcionalidade pelo índice de Pfeffer (P < 0,001; Pearson) e pior o índice cognitivo (P=0,018; Pearson). Por outro lado, quanto maior a concentração de TNF-alfa, piores os índices IS, PCS média e máxima e PCI média e máxima (P < 0,001; Pearson), maior o tempo de uso de próteses (P=0,010; Pearson) e pior o índice de placa O´Leary (P=0,008; Pearson). IL-6 e TNF-alfa se correlacionaram positivamente (P < 0,001; Pearson). Conclui-se que há um aumento sérico de citocinas associado ao comprometimento cognitivo e à doença periodontal. Estudos futuros poderão esclarecer os mecanismos que determinam aumento de IL-6 nas demências e aumento de TNF-alfa nas infecções periodontais e elucidar possíveis associações entre eles / Patients that present cognitive impairment, as Alzheimer´s Disease (AD), may have high prevalence of oral infections. Among them, chronic periodontitis is often associated to the increase of seric inflammatory biomarkers, and it recently has been referred as a factor than can change the progression of AD by its systemic mechanisms. The objective of this study was to investigate the prevalence of oral infections and seric levels of IL-1alfa, TNF-alfa and IL-6 in patients with AD, mild cognitive impairment (MCI) and non demented elderly. Sixty-five elderly were evaluated (21 with AD, 8 with MCI and 15 healthy). The evaluation included the Mini Mental State Exam, Questionnaire of Functional Activities (Pfeffer), periodontal evaluation, DMFT, Clinical Orofacial Questionnaire (EDOF-HC) and seric concentrations of IL-1beta, TNF-alfa and IL-6. The patients with AD and MCI had more absent teeth and for a longer period of time than the healthy elderly (P= 0.038) and periodontal disease (PD) was the main cause of teeth losses (P= 0.035). The patients had higher prevalence of candidiasis than the controls (P= 0.05). The serum level of IL-6 was higher in the patients that showed bad performance in the MMSE (P=0.018; Pearson) and daily life activities - Pfeffer (P < 0.001; Pearson). The TNF-alfa serum level was more elevated when patients had PPD, CAL, BI (P < 0.001; Pearson) and O\'Leary plaque index (P=0.008; Pearson). IL-6 e TNF-alfa were positively correlated (P < 0.001; Pearson). In conclusion, there is a seric increase of cytokines associated with the cognitive impairment and periodontal disease. Future studies are necessary to clarify the mechanisms that underlie the increase of IL-6 in dementias and the increase of TNF-alfa in periodontal infections and possible associations between them