Bakgrund: Den orala hälsan har förbättrats i Sverige de senaste åren och den oral hälsan är en del av den allmänna hälsan. Parodontit är en inflammatorisk parodontal sjukdom och sjukdomstillståndet progredierar utan behandling. Trots att den orala hälsan har förbättrats med åren, har många individer en hög risk för att utveckla sjukdomen. Parodontit har koppling till flertalet systemiska sjukdomar och demens. Alzheimers sjukdom [AS] är den vanligaste typen av demens. Även fast AS är en vanlig demenssjukdom, är patologin kring sjukdomen inte fullständigt klarlagd.  Syfte: Att undersöka samband mellan parodontit och utvecklingen av Alzheimers sjukdom. Metod: Arbetet är en litteraturstudie som är byggd på vetenskapliga artiklar från databaserna PubMed och CINAHL. Inkluderings- och exkluderingskriterier har använts för att få fram artiklar som svarar mot syftet. Relevansmall och kvalitetsgranskningsmall för exponeringsstudier från SBU har använts för att få fram artiklar av god kvalitet. Resultat: Litteraturstudiens resultat är indelade i skilda rubriker för att påvisa artiklarnas varierande resultat. Resultatet presenteras genom följande teman: ”Parodontit och högre risk för AS”, ”Kognitiva test”, ”Mikrobiell nivå” samt ”Oklart samband mellan parodontit och AS”. Totalt redovisas 15 artiklar. 13 artiklar påvisar ett samband mellan sjukdomarna, medan 2 artiklar inte påvisar något samband.  Slutsats: Majoriteten av artiklarna visade att parodontit kan bidra till utveckling och progression av demenssjukdomen AS. Två artiklar påvisade inget samband. / Background: The oral health has increased in Sweden the past years and the oral health is a part of the general health. Periodontitis is an inflammatory periodontal disease. Even though the oral health has generally improved over the years, several individuals have a high risk of developing periodontal disease. Periodontitis has relationship with several systemic diseases and dementia. Alzheimer’s disease [AD] is most common type of dementia, but the pathology of the disease is not yet clarified.  Aim: To study the relationship between periodontitis and the development of Alzheimer’s disease. Method: This literature study is based on scientific articles from the databases PubMed and CINAHL. Inclusions- and exclusions criteria has been used to obtain articles related to the aim. Relevant templates and quality reviews of exposing studies from SBU has been used to obtain articles of good quality. Results: The literature study’s results are divided into different headlines with the purpose to demonstrate the different results of the articles. The results are presented in following themes: “Periodontitis and risk of AD”, “Cognitive tests”, “Microbial level” and “Unclear connection between periodontitis and AD”. A total of 15 articles is presented. 13 of these articles demonstrate a relationship between the diseases, while 2 articles did not show a connection. Conclusion: Most of the articles showed that periodontitis can contribute to the development or progression of AD. Two articles did not show a relationship.

Porphyromonas gingivalis is a major etiological agent that is responsible for the cause and progression of periodontal diseases. The bacterium is exposed to various environmental conditions and oxidative stress conditions while it is in the oral cavity. So, P. gingivalis should have an efficient regulatory system in order to adjust and survive in the oral cavity. But little is known about the regulatory mechanisms that help the bacteria to survive in the oral cavity. So, it is essential to understand and characterize these regulatory mechanisms. The response and adaptation of P. gingivalis to environmental stress conditions occur at the level of transcription which involves the alternative sigma factors. Extracytoplasmic function (ECF) sigma factors are the largest group of alternative sigma factors that play a major role in bacterial response to environmental stress conditions. Here we characterize the σ-70 factor, SigH and SigG, the extracytoplasmic function sigma factors encoded in P. gingivalis genome. Our results show that the expression of SigH is upregulated when P. gingivalis is grown in the presence of oxygen. However, there is no change in the expression of SigG when grown in the presence of oxygen. Furthermore several genes involved in oxidative stress protection such as sod, trx, tpx, ftn, feOB and the hemin uptake locus, hmu, are downregulated in the mutant deficient in SigH designated as V2948. Our RNA-seq analysis of SigG showed that there is no change in the regulation of genes involved in oxidative stress protection and metal homeostasis in SigG deficient mutant designated as V3085. Our survival studies showed that both SigH and SigG are essential for P. gingivalis to grow in host cells. Collectively our studies demonstrate that SigH is a positive regulator of gene expression required for survival of the bacterium in the presence of oxygen and oxidative stress, hemin uptake and virulence. However our studies show that SigG is essential for the bacteria to grow in host cells and hence helps in the virulence of P. gingivalis.

Periodontal diseases are bacterially induced, inflammatory diseases which are responsible for loss of alveolar bone and connective tissue supporting the teeth which results in loss of teeth. Gram negative anaerobic bacteria are highly associated with these diseases. One of them is Porphyromonas gingivalis belonging to the phylum Bacteroidetes. Infection by P. gingivalis is recurrent after physical removal of the bacteria from the oral cavity and even after antibiotic treatment as development of resistance is not rare. Hence complete understanding the biology of this bacterium is of significance. This gram negative obligate anaerobe, being aerotolerant, manages to survive inside the oral cavity, where oxidative stress is ubiquitous. Genome sequence of P. gingivalis shows the presence of a transcriptional regulator OxyR which is a homologue of OxyR present in E. coli. P. gingivalis OxyR induces the expression of antioxidant defense genes like sod, ahpC-F, dps to protect the bacteria from oxidative stress. Expression of P. gingivalis OxyR regulon is not very well understood. Microarray studies carried out in our lab using P. gingivalis W83 to study gene regulation by OxyR, indicated that several genes in P. gingivalis are co-regulated by iron-and OxyR. Literature also supports that in iron deplete conditions genes involved in oxidative stress are down-regulated. These studies formed the basis of our hypothesis that OxyR might regulate the genes in P. gingivalis in an iron dependent manner. To study the mechanism of regulation by P. gingivalis OxyR and to determine whether OxyR regulation is iron dependent, two approaches were applied - in vitro characterization of binding and in vivo characterization. First step of in vitro characterization was to perform CHIP-chip assay to determine OxyR-binding sites present on the genomic DNA of P. gingivalis. As this assay was performed under completely anaerobic conditions, the target fragments to which OxyR was found to bind during this assay were not same as reported in literature. These and the fragments reported in literature were used for EMSA. EMSAs carried out using crude cell lysates and in vitro OxyR protein preparations showed expected results but the results were not reproducible. In vivo expressed and purified P. gingivalis OxyR never bound to the target fragments used. Preparation of a stable protein preparation and improvement in the parameters of EMSA is very important to further investigate the binding in vitro. The second approach is based on in vivo characterization of binding. This requires tagging the P. gingivalis OxyR at its C-terminus with fluorescent protein to observe its binding to the target DNA sequences. Fluorescently tagged OxyR, is expected to emit fluorescence from a highly localized area to produce sharp fluorescent spots when it is bound to its target sequences. Unbound OxyR is expected to emit a fluorescent signal which is spread over the entire area of the cell. This technique will help to determine the conditions under which OxyR binds to its target DNA sequences. This provides a means to confirm the results obtained from in vitro characterization instead of just extrapolating them.

Porphyromonas gingivalis, a gram-negative anaerobic, pathogenic bacterium is a major etiological agent in the initiation and progression of periodontal disease. Due to the ever-changing environment of the oral cavity, inhabitants like Porphyromonas gingivalis must possess the ability to adapt to changes in environmental conditions like pH, temperature, oxygen tension, and metal concentration. P. gingivalis should therefore have an efficient regulatory system in order to adapt and survive in the oral cavity. This response adaptation occurs at the transcriptional level, which involves alternative sigma factors. Extracytoplasmic function sigma (ECF-s) factors are the largest group of alternative sigma factors that play a role in the bacterial response to environmental stress conditions. Here we analyze the s-70 factor gene, PG0214, an extracytoplasmic function sigma factor encoded in the P. gingivalis genome, and examine its role in the bacterial response to environmental stress and virulence. Our findings indicate that the PG0214 gene is important in regulating major functional gene groups and pathways in the P. gingivalis genome. Strains deficient in the PG0214 gene were analyzed and shown to have decreased protease activity, as well as reduced survivability and invasion rates in eukaryotic host cells when compared against wild-type W83 and ATCC 33277 strains. Collectively our studies demonstrate that the PG0214 gene is a positive regulator of gene expression for the survival and virulence of P. gingivalis in the presence of oxidative- and iron-stress, although further study is needed to fully characterize the gene and determine its specific function.

El objetivo de esta investigación fue evaluar y comparar la efectividad antibacteriana de la pasta Tri mix e hidróxido de calcio frente a las bacterias Porphyromona gingivalis y Actinomyces odontolyticus prevalentes en conductos radiculares necróticos de dientes jóvenes. Se utilizaron dos cepas ATCC® Actinomyces odontolyticus (bacteria anaerobia facultativa) y Porphyromona gingivalis (bacteria anaerobia estricta) y se empleó el Método de Difusión en Pozos (MDP) en condiciones de anaerobiosis. Se realizó el primer control a la semana en el caso de Actinomyces odontolyticus y a los 20 días en el caso de Porphyromonas gingivalis. La mayor actividad antibacteriana fue dada por la pasta Tri mix, la cual presentó un halo de inhibición de 38 mm. La bacteria Porphyromona gingivalis fue inhibida completamente. / --- The aim of this study was to evaluate and compare the antibacterial activity between the Tri mix and calcium hydroxide paste against the bacterias Porphyromona gingivalis y Actinomyces odontolyticus prevalent in inmature teeth with necrotic pulps. For this study were used two ATCC® strains Porphyromona gingivalis (stric anaerobic bacterias) and Actinomyces odontolyticus (facultative anaerobic bacterias) by Difussion method in wells in anaerobic conditions. The reading of results was made at one week to Actinomyces odontolyticus and twenty days to Porphyromona gingivalis. The biggest antibacterial activity was produced by Tri mix paste, it showed a halo of inhibition 38 mm. The Porphyromona gingivalis was inhibited complety.

O ligamento periodontal e o tecido gengival são formados por tecido conjuntivo frouxo, sendo constituídos por diversas células, dentre as quais os fibroblastos são as mais numerosas. Ao serem submetidas a agressões diversas, estas células respondem com a liberação de substâncias, tais como citocinas e quimiocinas, que participam de maneira ativa no processo inflamatório, e com a produção de componentes da matriz extracelular fundamentais para o reparo, como por exemplo, o colágeno. Assim sendo, este trabalho teve como objetivo: Avaliar e comparar a expressão e a produção de prócolágeno tipo I, IL6, MIP1 e SDF1 por fibroblastos humanos, cultivados de ligamento periodontal e de tecido gengival, estimulados por lipopolissacarídeo (LPS) de Porphyromonas gingivalis. Foram coletados ligamentos periodontais de terceiros molares não irrompidos e biópsias de gengiva de um mesmo indivíduo (n=3). Estes tecidos foram picotados e mantidos em meio de cultura adequado para fibroblastos, que foram utilizados na quarta passagem. Após adesão dos fibroblastos a placas de 24 poços, o meio de cultura contendo 0,1 10 g/mL de LPS de P. gingivalis foi adicionado às placas em duplicata. O sobrenadante e as células foram coletados após 1, 6 e 24 horas e analisados por ELISA e PCR em tempo real, respectivamente. A análise estatística foi realizada por meio do programa GraphPad Prism, aplicandose o teste ANOVA a 1 critério com nível de significância de 5%. A expressão de prócolágeno tipo I mostrouse - ligeiramente diferente entre fibroblastos de ligamento periodontal e de gengiva. A produção de IL6, MIP1 e SDF1 foi significativamente maior em fibroblastos gengivais. A citocina IL6 foi produzida de maneira tempodependente com LPS de P gingivalis, principalmente por fibroblastos gengivais. Para MIP1, os fibroblastos gengivais mostraram maior produção com a menor concentração de estímulo (0,1g/ml). Para SDF1, foi detectada produção constitutiva que foi inibida com o aumento da concentração de LPS ao longo do tempo nestas mesmas células. Já para fibroblastos de ligamento periodontal, não foi observado um padrão homogêneo e linear, apesar de a produção basal de SDF1 também existir, porém em níveis bem mais discretos, como aquele observado para a produção de MIP1. A capacidade dos fibroblastos modificarem o padrão de produção dessas citocinas frente ao estímulo com LPS de P. gingivalis reforça a importância dessas células no contexto da resposta imune do indivíduo frente à doença periodontal. / The fibroblast is considered an important cell in periodontitis because it is the predominant cell type in the periodontal connective tissue. When challenged by different agents, fibroblasts respond through the release of substances, such as cytokines and chemokines that participate in an active way in the inflammatory process as well as the production of basic components of the extracellular matrix for repair, like collagen. The aim of this study was to: to evaluate and to compare the expression and production of type I procollagen, IL6, MIP1 and SDF1 by cultured human periodontal ligament and gingival fibroblasts challenged with lipopolyssacharide from Porphyromonas gingivalis. Human periodontal ligament and gingival fibroblasts were cultured from biopsies of the same donor and were used on the fourth passage. After confluence in 24well plates, the culture medium alone (control) or with 0,1 10 ug/mL of LPS from P. gingivalis were added and after 1, 6 and 24 hours, the supernatant and the cells were collected and analysed by ELISA and Real time PCR, respectively. Data were analysed by GraphPad Prism Program (1 way ANOVA test) and a significance level of 5% was adopted. Procollagen type I expression by Real Time PCR differ between periodontal ligament and gingival fibroblasts. In vitro experiments revealed that IL6, MIP 1 and SDF1 production were significantly greater in gingival fibroblasts when compared to periodontal ligament. In addition, IL6 was upregulated in a timedependent manner, mainly by the gingival fibroblasts. On one hand, MIP1 was stimulated with a low concentration (0,1ugml) of LPS by gingival fibroblasts. On the other hand, SDF1 was constitutively secreted by the same cells but its production was inhibited when challenged by a higher concentration of LPS from P gingivalis. In general, periodontal ligament fibroblasts did not show a pattern of production of these cytokines under the challenge with LPS, despite of the basal production of SDF1 in lower levels than gingival cells and the low production of MIP1 over time. The differential ability of the gingival and periodontal ligament fibroblasts to secrete these cytokines emphasizes their crucial role in the inflammatory microenvironment and in the host immune response to periodontal disease.

Matrix metalloproteinases (MMP) are zinc- or calcium-dependent proteinases involved in the normal maintenance of the extracellular matrix. When elevated, MMPs degrade matrix components contributing to tissue destruction in infected periodontal sites. The objectives of this study were two-fold: first to assess the ability of Porphyromonas gingivalis hemagglutinin B (HagB) to induce MMP responses in human myeloid dendritic cells and second, to assess the effect of host defense peptide human β defensin 3 (HBD3) to regulate and attenuate the MMP response of HagB treated dendritic cells. HBD3 (0.2, 2.0, or 20.0 µM) was given to primary dendritic cells pre-, co-, or post-treatment to HagB (0.02 or 0.2 µM). At 16 hours, MMP concentrations were determined. There were no significant differences in concentrations for all 3 replications for MMP-2 and -13. There were few significant differences in some of the replications for MMP-3, -7, and -9. There were more pronounced differences in MMP-1, -10, and -12 expression, which were significantly influenced by both the concentration of HBD3 and the timing of administration. Chemokine and cytokine responses were inversely related to MMP production. While MMP responses decreased in a dose related manner, chemokine responses were increased. Concentrations of MIP-1α were high and there were no differences in response to 0.02 and 0.2 M HagB with or without 20.0 M HBD3. However, the MIP-1β and TNFα response to 0.2 M HagB were only attenuated. HagB induces the production of MMPs in dendritic cells and treatment of dendritic cells with HBD3 can alter the profile of HagB-induced MMPs. Such a finding may have importance in the pathogenesis of periodontal disease.

Abstract not available

published_or_final_version / Medicine / Master / Master of Medical Sciences

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences