Uma das estratégias mais promissoras para a biotecnologia de vacinas é o desenvolvimento de linhagens precisamente atenuadas, e que possam ser usadas como carregadoras de antígenos heterólogos. Mutantes de <i}>Salmonella Typhimurium têm sido extensivamente utilizados com essa fmalidade. A flagelina, monômero constituinte do filamento flagelar, vem sendo empregada como carregadora de antígenos heterólogos, inseridos na região central, hipervariável (região IV). Inserções nessa região são freqüentemente funcionais, e levam à exposição do epitopo na superfície do filamento. O presente trabalho explora o potencial de outras regiões da molécula para a inserção de epitopos. Nós inserimos a mesma seqüência usada anteriomente (epitopo da proteína M de S. pyogenes, Tipo 5) em regiões com diferentes níveis de homologia (III e VI), e em região totalmente conservada (VIII). Também foram feitas inserções duplas em regiões que se mostraram toleráveis (III e IV; IV e VI). Todas as proteínas híbridas foram sintetizadas pela Salmonella, como demonstrado em imunoblots, usando anticorpo contra a flagelina e contra o peptídeo. Todas as regiões, exceto a VIII, aceitaram a inserção sem perda de motilidade, apesar de, em alguns casos, ela ter sido extremamente reduzida. A imunogenicidade foi avaliada pela imunização de camundongos com bactérias vivas, inativadas ou, quando possível, flagelina purificada. Os resultados foram similares aos descritos na literatura para inserções envolvendo a região IV, obtendo-se um elevado título de anticorpos contra flagelina. Um baixo nível de anticorpo contra o peptídeo também foi detectado para todas as novas linhagens testadas. Nossos resultados com imunização de bactérias vivas sugerem uma resposta levemente melhor ao peptídeo quando duas cópias estão presentes, mas os dados não são conclusivos. / One of the most promising strategies for the biotechnology of vaccines is the development of precisely attenuated strains, which could be used as carriers of heterologous antigens. Mutants of Salmonella Typhimurium have been extensively explored to this effect, since the infection ofmice by S. Typhimurium mimics the infection of humans by S. Typhi, and the genetics of the species is extremely well known, making it easy the obtention of defined mutants with reduced pathogenicity. Mutants with auxotrofy in genes of the aromatic pathway are particularly attractive, since they need PABA and DHB to grow, and these compounds are unavailable in mammalian tissues. Flagellin, the monomer which constitutes the flagellar filament, has been used as a carrier for heterologous epitopes, inserted in a central, hypervariable region (region IV). Insertions in this region are often functional, and lead to exposition of the epitope at the filament\' s surface. The present work explored the potential of the other regions ofthe molecule for the insertion of epitopes. We inserted the same reporter sequence (MS epitope from S. pyogenes M protein) in regions with different levels of homology (III and VI), and totally conserved (VIII). We also made double insertions in regions shown to be permissive (III and IV; IV and VI). All hybrid proteins were synthesized by Salmonella, as demonstrated by immunoblots using antibody against flagellin and against the synthetic peptide. All regions, except the highly conserved region VIII, accepted the insertions without loss of motility, albeit, in some cases, motility was seriously reduced. Immunogenicity of the hydrids was evaluated by immunization with live bacteria, killed bacteria, and purified flagellin (when possible). Results obtained with the new constructs were similar to the ones published for insertions involving region IV, in the sense that antibody titers to the carrier protein were very high. A low level of antibody to the inserted peptide was also detected in all groups of animals. Our results with live immunization suggest a slightly better response to the peptide when two copies are present, but the data are not conclusive.

A função e a arquitetura dos genes está começando a ser elucidada a partir do estudo de genomas completos tanto de procariotos como de eucariotos. Diversos estudos foram ultimamente realizados a respeito de exon shuffling do ponto de vista evolutivo, fenômeno relacionado à origem de novos genes através de recombinações de DNA mediadas por introns. Apesar de eventos de exon shuffling serem responsáveis pelo aumento da modularidade gênica, outros processos foram desenvolvidos ao longo da evolução para que houvesse o aumento da diversidade do proteoma sem a conseqüente expansão dos genomas, sendo splicing alternativo um dos mais freqüentes. Apresentamos nesta dissertação duas extensivas análises: 1) a análise de uma base de dados de genes eucarióticos contendo pelo menos um intron que apresentou excesso de introns de fase 0 e exons simétricos, dados que suportam exon shuffling como um importante mecanismo de evolução gênica. Avaliamos também a confiabilidade de introns preditos por programas de computador através de alinhamento de ESTs; e 2) a análise do uso alternativo de exons (UAE), um tipo de splicing alternativo, em transcritos humanos detectando que cerca de 51% dos genes humanos possuem mais de uma variante de splicing e que este tipo de processamento pós-transcricional parece ser mais freqüentemente encontrado em tecidos tumorais. / Abstract not available.

A biotecnologia é definida como qualquer aplicação tecnológica que utilize sistemas biológicos, organismos vivos, ou seus derivados, para fabricar ou modificar produtos ou processos para alguma utilização específica (ORGANIZAÇÃO DAS NAÇÕES UNIDAS, 1992). Os produtos biotecnológicos devem atender certas especificações exigidas pela Agência Nacional de Vigilância Sanitária (ANVISA), Food and Drug Administration (FDA), European Medicine Agency (EMEA) e Wood Health Organization (WHO). Para isso, utilizam-se técnicas rotineiras aplicadas à pesquisa e análise de biomoléculas como Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE), Western blot, Enzyme-Linked Immunosorbent Assay (ELISA) e espectrometria de massas (MS). A abordagem do Monitoramento de Reações Múltiplas (MRM) é considerada uma interessante alternativa aos ensaios imunoenzimáticos para caracterização e quantificação total de proteínas terapêuticas, sejam elas recombinantes ou não (KIM e DOYLE, 2010). Esta abordagem é baseada nos fundamentos da proteômica quantitativa pela utilização da cromatografia líquida acoplada à espectrometria de massas sequencial (LCMS/MS) cuja plataforma apresenta alta especificidade, sensibilidade e reprodutibilidade quantitativa em suas análises para detecção simultânea de várias regiões da estrutura proteica. Em vista disso, estabeleceu-se uma metodologia para quantificação do FVIII recombinante (FVIIIr) produzido pela linhagem celular humana Sk-Hep-1 ou do FVIII derivado do plasma (FVIIIdp), ambos utilizados no tratamento da Hemofilia A (HEMA). Para o estabelecimento da metodologia, toda uma estratégia de seleção e síntese química de peptídeos representativos das cadeias pesada e leve do FVIII humano foi empregada. Tais peptídeos obtidos foram utilizados como padrões das análises. Além disso, foi demonstrada a relação direta entre a quantificação total do FVIII com técnicas convencionais como ELISA, possibilitando a aplicação rotineira dessa abordagem para quantificação do FVIIIr e do FVIIIdp. / Biotechnology is defined as any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for a specific use (ORGANIZAÇÃO DAS NAÇÕES UNIDAS, 1992). Biotechnological products must meet certain specifications required by Agência Nacional de Vigilância Sanitária (ANVISA), Food and Drug Administration (FDA), European Medicine Agency (EMEA), and Wood Health Organization (WHO). For that routine techniques applied to research and analysis of biomolecules such Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE), Western blot, Enzyme-Linked Immunosorbent Assay (ELISA), and mass spectrometry (MS) are utilized as quality control techniques. The MS-based approach termed Multiple Reaction Monitoring (MRM) is considered an interesting alternative to immunoassays for the total quantification and characterization of therapeutic proteins, whether recombinant or not (KIM e DOYLE, 2010). This approach is based on the fundamentals of quantitative proteomics and uses of liquid chromatography coupled to tandem spectrometric mass (LC-MS/MS) to obtain a highly specific, sensitive and reproducible analysis for quantification of multiple regions of a given protein structure. Here, we established a methodology for total quantification of recombinant FVIII (rFVIII) produced in Sk-Hep-1 human cell line or of plasma derived FVIII (pdFVIII), both used in the treatment of Hemophilia A (HEMA). For that, we adopted a strategy of selection and chemical peptide synthesis of representative peptides of the heavy and light chains of human FVIII, which were used as standards in the analysis. The quantitative MRM method developed here indicated a direct correlation with FVIII quantitative techniques such ELISA, which allows routine application of such approach for rFVIII and pdFVIII quantification.

A lagarta L. obliqua tem se destacado por apresentar em sua hemolinfa proteínas com atividade biológica demonstrada em cultivos celulares. A literatura disponível não apresenta trabalhos sobre a expressão da proteína antiapoptótica de L. obliqua, então este estudo objetiva a clonagem e expressão da proteína antiapoptótica presente na hemolinfa de L. obliqua, em sistema bacteriano Escherichia coli. O RNAm extraído do tegumento de L. obliqua deu origem a um cDNA obtido por RT-PCR, o qual foi clonado em vetor pCR II-TOPO para posterior transformação de bactérias E. coli JMQC. Na expressão heteróloga, o fragmento foi subclonado em vetor pET28a e transformadas bactérias E. coli BLQC. A indução de expressão foi realizada com IPTG 1 mM. A APLOrEC purificada por cromatografia foi identificada por Western Blot. A atividade biológica da APLOrE foi analisada em células VERO e L929 após indução de morte e verificou-se que esta protegeu os cultivos induzidos com 4mM de H2O2 portanto, eficaz na manutenção estrutural do citoesqueleto destas células. / The caterpillar L. obliqua has become known for performing in their hemolymph proteins with biological activity demonstrated in cell cultures. The available literature does not provide studies on the expression of antiapoptotic protein L. oblique, so this study aims cloning and expression of anti-apoptotic protein present in the hemolymph of L. oblique, bacterial system in Escherichia coli. The extracted mRNA L. obliqua husk gave a cDNA obtained by RT-PCR, which was cloned into pCR II-TOPO vector for subsequent transformation of E. coli bacteria JMQC. The heterologous expression, the fragment was subcloned into pET28a vector and transformed E. coli bacteria BLQC. The induction of expression was performed with 1 mM IPTG. The APLOrEC purified by chromatography was identified by Western blot. The biological activity was examined in APLOrE VERO and L929 cells after death induction, and it was found that this protected crops H2O2 induced with 4mM therefore effective in the structural maintenance of the cytoskeleton of such cells.

Streptococcus pneumoniae é o patógeno causador de diversas doenças com alta mortalidade e morbidade, como meningite e pneumonia. As vacinas disponíveis baseiam-se na resposta contra o polissacarídeo capsular (PS), porém possuem elevado custo e cobertura limitada aos sorotipos vacinais. O objetivo deste estudo foi avaliar a eficácia da imunização nasal com PspAs recombinantes de família 1 (rPspA1 e rPspA2) e de família 2 (rPspA3, rPspA4 e rPspA5) em um modelo de cocolonização da nasofaringe de camundongos, utilizando isolados que expressam diferentes PspAs (PspA1 ao PspA4). Esse modelo visa analisar a eficácia da vacinação frente à exposição a diferentes pneumococos, uma situação comum, especialmente em crianças. Os experimentos deste projeto avaliaram a colonização com misturas de isolados dos sorotipos 6B e 23F e expressando PspA1, PspA2, PspA3 ou PspA4, mostrando uma análise ampla da cobertura vacinal contra pneumococo das diferentes formulações contendo as variantes do antígeno PspA e a importância desse antígeno para o desenvolvimento de uma nova vacina. / Streptococcus pneumoniae is the cause of several diseases with high mortality and morbidity, such as meningitis and pneumonia. The available vaccines are based on the response against the capsular polysaccharide (PS), but they have a high cost and coverage restricted to the vaccine serotypes. The purpose of this study was to evaluate the efficacy of nasal immunization with recombinant PspAs from family 1 (rPspA1 and rPspA2) and from family 2 (rPspA3, rPspA4 and rPspA5) in a model of co-colonization of the mouse nasopharynx, using isolates expressing different PspAs (PspA1 to PspA4). This model aims to analyze the effectiveness of vaccination upon exposure to different pneumococci, a common situation, especially in children. The experiments in this project assessed colonization with mixtures of isolates of serotypes 6B and 23F, expressing PspA1, PspA2, PspA3 or PspA4, showing a wide vaccination coverage analysis of different formulations containing the PspA variants against pneumococcus and the importance of this antigen to the development of a new vaccine.

Le traitement de l'anémie en insuffisance rénale chronique (IRC) avec l'érythropoïétine recombinante humaine (rhEPO) est accompagné d'une élévation de la pression artérielle. Cet effet presseur de l'rhEPO est présent seulement en IRC. En effet, l'rhEPO n'augmente pas la pression artérielle en condition rénale normale. Nos objectifs sont donc d'élucider les mécanismes qui permettent le maintien de la pression en condition normale et l'effet hypertenseur de l'rhEPO en IRC. Dans une première étude, l'rhEPO est administrée chez des rats Wistar normaux (100U/kg, 3 fois par semaine pendant 3 semaines) tandis qu'un second groupe de rats témoins reçoit le véhicule (saline). L'effet de l'rhEPO sur la réactivité vasculaire est évalué dans des segments d'aorte thoracique isolés. L'expression de l'endotheline-1 (ET-1) et de la NO synthase endothelial (eNOS) est analysée par immunofluorescence en microscopie confocale dans ces mêmes vaisseaux. Les résultats montrent que la pression artérielle systolique et la creatinine sérique sont inchangées chez les animaux traités alors que l'hématocrite est augmenté chez les animaux recevant l'rhEPO. Le traitement à l'rhEPO provoque une augmentation de la contraction à la norepinephrine (NE) dans les segments sans endothelium seulement. D cause également une atténuation de la contraction à l'ET-1 dans les segments dont 1'endothelium est intact ; ce phénomène est corrigé en absence de l'endothélium. L'incubation des segments avec le N -nitro-L-arginine méthyl ester (LNAME), un inhibiteur de la synthèse du monoxide d'azote (NO), rétablit aussi la contraction à l'ET-1. L'expression de l'ET-1 dans l'endothélium des aortes thoraciques demeure inchangée tandis que l'expression de la eNOS est augmentée suite au traitement à l'rhEPO. L'rhEPO entraîne donc l'activation d'un mécanisme compensateur vasodilatateur de l'endothélium. Ce mécanisme impliquerait l'augmentation de la relâche de NO suite à une expression accrue de la eNOS. Dans un deuxième temps, nous avons vérifié l'état de ce mécanisme compensateur en IRC. Nous avons donc comparé un groupe de rats Wistar rendus uremiques par néphrectomie 5/6 (Nx) à un groupe de rats témoins. Les mêmes analyses ont été effectuées pour cette étude. Nous avons observé une augmentation de la pression artérielle ainsi qu'une détérioration de la fonction rénale chez les animaux uremiques. L'IRC ne cause aucune altération de la réponse à F acetylcholine (ACh) mais atténue cependant la vasodilatation au nitroprussiate de sodium (SNP). L'IRC cause également une augmentation de la réponse à la NE dans les segments sans endothelium seulement. La contraction à l'ET-1 est diminuée dans les segments d'aorte des rats Nx dont l'endothélium est intact tandis qu'elle est partiellement accentuée en son absence. La contraction à l'ET-1 est aussi augmentée par l'incubation des segments d'aorte de rats Nx avec le L-NAME. Ces résultats suggèrent que l'atténuation de la réponse à l'ET-1 dans les vaisseaux des rats Nx est causée en partie par une augmentation de la production endothéliale de l'ET-1. Par contre, l'urémie accentue aussi la relâche d'un facteur vasodilatateur, dont le NO, pour contrecarrer l'action des agents vasoconstricteurs (ET-1, NE). En effet, l'expression endothéliale de la eNOS est aussi augmentée dans les vaisseaux des animaux Nx. Enfin, nous avons comparé les mêmes paramètres chez les animaux uremiques recevant ou non le traitement à l'rhEPO. L'rhEPO aggrave l'hypertension et détériore la fonction rénale présente en IRC. L'rhEPO diminue la relaxation à l'ACh et au SNP. Le traitement à l'rhEPO ne modifie pas la contraction à la NE. Elle augmente cependant l'atténuation de la réponse à l'ET-1 en présence de l'endothélium. L'absence d'endothélium et l'incubation avec le L-NAME rétablissent partiellement la contraction à l'ET-1 de façon similaire chez les animaux Nx recevant ou non l'rhEPO. Ces résultats indiquent que l'augmentation de l'expression endothéliale de l'ET-1 par le traitement à l'rhEPO en urémie peut être responsable de l'atténuation accrue de la contraction à l'ET-1 chez les animaux Nx traité à l'rhEPO. Tout comme chez les animaux normaux, l'rhEPO entraîne une augmentation de la relâche de NO suite à l'expression accrue de la eNOS. Ce mécanisme serait par contre insuffisant pour bloquer l'effet hypertenseur de l'rhEPO en urémie. En conclusion, une augmentation de la production de NO suite à l'expression accrue de la eNOS explique, du moins en partie, le maintien de la pression artérielle en condition normale suite au traitement à l'rhEPO. Ce mécanisme compensateur est également activé en IRC mais ne serait pas modulé par le traitement à l'rhEPO. Il serait alors insuffisant pour prévenir l'augmentation de la pression artérielle. / Treatment of anemia in chronic renal failure (CRF) with recombinant human erythropoietin (rhEPO) is associated with increased blood pressure. This hypertensive effect of rhEPO is present only in CRF. Indeed, rhEPO does not increase blood pressure in normal renal conditions. The aim of our work is to elucidate the mechanisms involved in the maintenance of normal blood pressure in normal conditions and the hypertensive effect induced by rhEPO in CRF. In a first study, normal Wistar rats were treated with rhEPO (100U/kg, 3 times per week for 3 weeks) while the second group of control rats received the vehicle (saline). The effect of rhEPO on vascular reactivity was evaluated in isolated thoracic aorta segments. The expression of endothelin-1 (ET-1) and endothelial nitric oxide synthase (eNOS) was assessed by immunofluorescence with confocal microscopy in these same vessels. The results show that blood pressure and serum creatinine were unchanged in normal rats treated with rhEPO, whereas hematocrit was increased in the same animals. RhEPO caused an increase of contraction response to norepinephrine (NE) only in segments without endothelium. It also caused an attenuation of ET-1 contraction in segments where endothelium was intact; this phenomenon was corrected in the absence of endothelium. The incubation of segments with NG -nitro-L-arginine methyl ester (L-NAME), a nitric oxyde (NO) synthesis inhibitor, also restored the ET-1 contraction. ET-1 expression in thoracic aorta endothelium was unchanged, whereas eNOS expression was increased after rhEPO therapy. Thus, rhEPO activates an endothelium-dependent compensatory mechanism. This mechanism involves increased NO release due to enhanced expression of eNOS. Secondly, we evaluated this compensatory mechanism in CRF. Wistar rats were rendered uremic by subtotal 5/6 nephrectomy and were compared with sham-operated control rats. The analyses in the first study were repeated. We found an increase in blood pressure and a deterioration of renal function in uremic rats. CRF did not affect the response to acethylcholine (Ach) but decreased sodium nitroprusside (SNP) vasorelaxation. However, CRF led to an alteration in the contraction response to NE in thoracic aorta segments without endothelium. The contraction to ET-1 was attenuated in segments from uremic rats with intact endothelium whereas it was partially increased in its absence. The ET-1 contraction was also restored by the incubation of segments with L-NAME. These results suggest that the attenuation of the ET-1 response in uremic rats is related, at least in part, to the increase in endothelial ET-1 production. On the other hand, uremia also accentuates the endothelial release of vasodilators, such as NO, which counteract the effects of the vasoconstrictors (ET-1, NE). Moreover, the endothelial expression of eNOS was also increased in vessels from uremic rats. Finally, we compared the same parameters in uremic rats with and without rhEPO treatment. rhEPO aggravated hypertension and exacerbated the deterioration in renal function already present in CRF. rhEPO led to a decrease in the vasodilatation to ACh and SNP. Treatment with rhEPO had no effect on the contraction to NE. However, it increased the attenuation of ET-1 contraction in thoracic aorta segments with endothelium. Endothelium denudation and incubation with L-NAME partially restored the contraction to ET-1 similarly in untreated and rhEPO-treated uremic rats. These results indicate that the increased endothelial expression of ET-1 induced by rhEPO in uremic rats is responsible for the increase in the attenuation response to ET-1. In the same way, as in normal rats, rhEPO led to an increase in NO release due to increased eNOS expression. However, this mechanism appears to be insufficient to prevent the vasopressor effect of rhEPO in uremia. In conclusion, increased production of NO as a result of increased eNOS expression may explain, at least in part, the maintenance of normal blood pressure under normal condition following rhEPO therapy. This compensatory mechanism is also activated in uremia, but is unaffected by rhEPO, and its effect is thus insufficient to prevent the development of hypertension in CRF.

La correction de l'anémie par l'érythropoïétine recombinante humaine (rhEPO) en insuffisance rénale chronique (IRC) s'accompagne d'une élévation de la pression artérielle. Les mécanismes presseurs de l'rhEPO en IRC sont encore mal définis. Des études récentes indiquent que le traitement à l'rhEPO accentue la dysfonction endothéliale déjà présente en urémie. On note une élévation de la production endothéliale d'endothéline-1 (ET-1) et une diminution de la relâche de monoxyde d'azote (NO). Ces changements pourraient aussi être associés à une augmentation de la formation d'espèces réactives de l'oxygène (ROS) qui peut accentuer ces changements. Notre étude a pour objectif d'évaluer l'effet d'un antioxydant, le tempol (un mimétique de la superoxide dismutase (SOD)), sur la pression artérielle et la progression de l'insuffisance rénale chez le rat urémique traité à l'rhEPO. Pour ce faire, des rats Wistar rendus urémiques par néphrectomie subtotale 5/6 sont divisés en quatre goupes : urémique (Nx) + véhicule; Nx + rhEPO; Nx + tempol (lmmol/1/jour dans l'eau à boire); et Nx + rhEPO + tempol, pendant quatre semaines. Les rats développent de l'urémie, de l'anémie et de l'hypertension artérielle. Ces derniers effets sont associés à une élévation des concentrations d'ET-1 et de la production de fanion superoxyde. Le traitement à l'rhEPO chez les rats urémiques corrige l'anémie, mais aggrave l'hypertension artérielle et l'insuffisance rénale de même que l'augmentation d'ET-1 et de fanion superoxyde. Le traitement au tempol, chez les deux groupes urémiques, atténue le développement de l'hypertension et la progression des dommages histologiques rénaux qui sont d'ailleurs associés à une réduction des concentrations ET-1 plasmatique, urinaire et rénale ainsi qu'une diminution de la production de fanion superoxyde. En conclusion, le développement de l'hypertension et la progression de l'insuffisance rénale chez le rat urémique sont causés, en partie, par la présence d'un stress oxydatif. Le traitement à l'rhEPO accentue d'avantage le stress oxydatif, et ce dernier serait impliqué dans l'aggravation de l'hypertension et de la progression de l'insuffisance rénale.

La correction de l'anémie par l'érythropoïétine recombinante humaine (rhEPO) en insuffisance rénale chronique (IRC) s'accompagne d'une augmentation de la pression artérielle. Nos travaux antérieurs indiquent que l'rhEPO accentue la dysfonction endothéliale qui est présente en IRC en augmentant la production d'endothéline-1 (ET-1). Par contre, en condition rénale normale, la pression artérielle et la concentration vasculaire d'ET-1 demeurent inchangées suite au traitement à l'rhEPO. Ces résultats suggèrent que l'rhEPO exerce un effet différent sur la production des hormones vasoactives telles la thromboxane A2 (TXA2) et la prostacycline (PGL) et sur le système ET-1 en IRC et chez l'animal normal. Notre étude démontre que l'administration d'rhEPO en IRC s'accompagne d'une augmentation supplémentaire de TXA? alors que le niveau de PGL demeure inchangé. Le ratio TXA2/PGL est donc augmenté ce qui suggère que la production de PGL est insuffisante pour contrer les effets de la TXA2. En effet, le blocage de la synthèse de TXA2 avec le ridogrel prévient l'hypertension artérielle induite par l'rhEPO en urémie alors que le blocage simultané de la TXA2 et de la PGI2 avec l'acide acétylsalicylique est inefficace. Ces résultats soulignent l'importance de préserver la production de PGI2 lors de l'administration d'rhEPO en IRC. Chez l'animal normal, nous avons observé que l'administration d'rhEPO n'affecte pas la pression artérielle et la concentration vasculaire d'ET-1. Nous avons alors émis l'hypothèse que le récepteur (R) ETB (impliqué dans la clairance) pourrait jouer un rôle compensateur sur la pression artérielle et la clairance de l'ET-1 lors de l'administration d'rhEPO chez l'animal normal. En effet, nos résultats démontrent que l'expression de PARNm du récepteur ETH est augmentée ainsi que sa densité sur l'endothélium des vaisseaux d'animaux traités à l'rhEPO. Afin de démontrer l'effet compensateur du récepteur ETB, nous avons administré de l'rhEPO à des souris ETBR hétérozygotes <+) , ETA<+/_) et sauvages. Le traitement à l'rhEPO cause une augmentation significative de la pression artérielle et de la concentration vasculaire d'ET-1 seulement chez les souris ETBR(+/) . Ainsi, ces résultats démontrent que l'rhEPO peut moduler le système ET1/ETHR en condition normale. Cette augmentation de l'expression du récepteur ETB pourrait contribuer à maintenir la pression artérielle lors de l'administration d'rhEPO à des animaux normaux. À l'inverse, des conditions où le récepteur ETB est déficitaire, comme chez les souris ETBR ( + ) et lors de ITRC, pourraient entraîner une augmentation de la pression artérielle lors de l'administration d'rhEPO. Des analyses de l'expression de gènes par microarray ont aussi été menées sur les aortes de ces rats. Les résultats révèlent que l'effet de l'rhEPO sur l'expression des gènes est différent entre les rats normaux et urémiques. En effet, l'analyse de ces données suggère que des gènes comme la superoxyde dismutase et la glutathionc peroxydase pourraient être impliqués dans l'hypertension artérielle induite par l'rhEPO en IRC. Ces résultats permettent d'identifier de nouvelles avenues de recherche qui permettront d'élucider les mécanismes physiopathologiques de cette forme iatrogénique d'hypertension artérielle. En conclusion, mes travaux de recherche au doctorat révèlent que l'rhEPO exerce une action pléiotropique sur les vaisseaux sanguins et cette action est différente entre le rat normal et le rat urémique. Chez l'animal urémique, l'rhEPO accentue la dysfonction endothéliale déjà existante et l'hypertension artérielle alors que chez le rat normal, l'administration d'rhEPO est associée à des mécanismes compensatoires permettant de maintenir la pression artérielle à un niveau normal. Nos résultats fournissent des évidences d'un nouveau rôle modulateur de l'rhEPO sur les vaisseaux sanguins et permettront de développer des approches thérapeutiques plus spécifiques pour le traitement de l'hypertension artérielle induite par l'rhEPO en IRC. / The treatment of anemia with recombinant human erythropoietin (rhEPO) in chronic renal failure (CRF) induces hypertension. Our previous studies showed that rhEPO increases the existing endothelial dysfunction in rats with CRF by stimulating the production of endothelin-1 (ET-1). In contrast, in normal animals, blood pressure and vascular ET-1 concentrations remain unchanged following rhEPO therapy. These results prompted us to verify whether rhEPO exerts a different effect on the production of vasoactive hormones such as thromboxane A2 (TXA2) and prostacyclin (PGI2), and on the vascular ET-1 system in CRF and normal animals. Our study showed that rhEPO administration in CRF rats is associated with a further increase in vascular TXA2 concentrations, while prostacyclin (PGE) levels remained unchanged. The ratio of TXA2/PGI2 was increased, suggesting that PGI2 production is insufficient to oppose the effects of TXA2. Consistent with this finding, TXA2 synthesis blockade with ridogrel prevented rhEPO-induced hypertension in uremic rats while the inhibition of the synthesis of both TXA2 and PGI2 with acetylsalicylic acid was ineffective. These results stress the importance of preserving PGI2 production when treating rhEpoinduced hypertension in CRF. In normal animals, we observed that rhEPO administration does not affect blood pressure and vascular ET-1 concentrations. We hypothesised, that the ETB receptor (a clearance receptor) could play a compensatory role in maintaining ET-1 levels in normal animals under rhEPO treatment. In keeping with that, the vascular expression of the ETB receptor as well as its endothelial density were increased in normal rats receiving rhEPO. To further document the compensatory role of the ETB receptor (R), we administered rhEPO to ETBR heterozygous <+/) , ETAR <+/_) and wildtype mice. The administration of rhEPO caused an increase in blood pressure and vascular ET-1 concentrations in ETBR mice exclusively. These results indicate that rhEPO can modulate the endothelial ET-1/ETBR system in normal conditions. This increase in endothelial expression of the ETBR may contribute to maintaining normal blood pressure during rhEPO administration in normal animals. In contrast, conditions with deficient ETBR expression, such as in ETBR( + ' mice orCRF rats, may lead to hypertension while receiving rhEPO therapy. Microarray gene expression analyses were also performed on the aorta of these rats. We observed that the effect of rhEPO on gene expression is different between normal and uremic rats. Indeed, the results suggest that genes such as superoxide dismutase and glutathione peroxydase might be involved in hypertension induced by rhEPO in CRF. These results pave the way toward new research directions in elucidating the physiopathogenic mechanisms of this iatrogenic form of hypertension. In conclusion, my doctoral studies reveal that rhEPO exerts a pleiotropic action on blood vessels and this action is different between normal and CRF animals. In uremic conditions, the administration of rhEPO aggravates the existing endothelial dysfunction and hypertension whereas in normal animals there are compensatory mechanisms that contribute to maintaining blood pressure normal. Our results provide further insights into novel modulatory actions of rhEPO on blood vessels which are highly relevant to the development of more specific and rational approaches for the management of rhEPOinduced hypertension in CRF.

Made available in DSpace on 2011-05-04T12:36:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2009 / Entre os objetivos da Política Nacional de Medicamentos constam o acesso e o financiamento dos denominados medicamentos de dispensação em caráter excepcional (MDCE). Estes, conhecidos por representarem um gasto governamental relativamente alto, se destinam ao tratamento de doenças em sua maioria, crônicas , que atingem uma pequena parcela da população. Para respaldar sua utilização promovendo adequada alocação dos recursos e o uso racional, o Ministério da Saúde publica protocolos clínicos e diretrizes terapêuticas (PCDT), cujo cumprimento é pré-requisito para o acesso dos pacientes a esses medicamentos pelo programa governamental. A adesão dos prescritores aos protocolos é fator imprescindível ao sucesso desta estratégia. O presente estudo busca verificar, mediante critérios objetivos, o grau de cumprimento pelos prescritores dos procedimentos-chave eleitos a partir do PDCT selecionado. Realizado estudo transversal descritivo com prontuário como fonte de dados e sua revisão como estratégia. Tratamento da anemia em pacientes portadores de Insuficiência Renal Crônica (IRC) com o medicamento eritropoetina humana recombinante (EPO) foi eleita como situação traçadora. Escolhidas três unidades de saúde, sendo critérios o número de pacientes acompanhados e a natureza da organização. No banco de dados da Secretaria de Estado de Saúde do Rio de Janeiro, destinado ao acompanhamento da dispensação dos MDCE identificou-se universo de 411 pacientes com CID principal registrado para autorização de dispensação N18.0 e N18.8, que retiraram o medicamento em algum momento entre janeiro de 2004 a dezembro de 2005. Elegidos procedimentos chave do fluxograma de tratamento do PCDT para a condição traçadora como critérios de verificação. Foram revisados prontuários de 202 pacientes renais crônicos que receberam o medicamento por um período de até dois anos de acompanhamento. Quanto ao grau de adesão ao PDCT, 38,1% foram classificados como adequados, 48,5% como regular, 10,4% como insuficiente e 3% como inadequado. Os critérios mais seguidos foram: critério de inclusão valor do hematócrito ou da hemoglobina, realização inicial de hemograma completo e de contagem de plaquetas e exame de monitorização desses últimos. Os menos seguidos foram: dose inicial e suspensão temporária. No geral, há uma boa adesão, porém essa pode ser melhorada. A análise de possíveis barreiras a adesão faz-se mister. / One of the National Medicines Policy goals is to guarantee the access and funding of the group of drugs called medicines of dispensation in exceptional character (MDEC). These expensive drugs are intended for the treatment of diseases - most of them, chronic - that affect a small portion of the population. In this way, they are know to represent high cost to the public service in Brazil. To support the appropriate allocation of resources and rational use, the Health Ministry develops and public the Clinical protocols and standard treatment guidelines (CPSTG) which is essential for the patient access to the governmental program. To perceive this benefits physicians adherence is necessary. The study aims to evaluate, by objective criteria, the degree of physicians’ adherence to CPSTG. A descriptive cross-sectional study was conducted, using medical records review. CPSTG for the treatment of anemia in chronic renal patients with recombinant human erythropoietin (EPO) was chose to evaluation the adherence. Three units of health were chosen to participate due to number of patients and nature of the organization. The population was picked out from the database of the Secretary of State of Health of Rio de Janeiro, which monitor the distribution of MDEC. The universe was 411 patients with principal ICD registered N18.0 and N18.8, which withdrew the drug at some time between January 2004 to December 2005. To verify the adherence to statements from CPSTG was elected key procedures from CPSTG the treatment of anemia in patients with Chronic Renal Failure (CRF) using EPO flowchart. 202 chronic renal patients medical records were reviewed who received the drug for up to two years of monitoring. The characteristics of patients in the study were similar to the patients described in the 2008 Brazilian Census of Dialysis. Among the comorbidities presented by patients, 76.24% had hypertension and 7.42% ischemic heart disease or congestive heart failure. Regarding adherence, 38.1% were classified as adequate, 48.5% regular, 10.4% insufficient and 3% as inadequate. The most followed criterias were: criterion for inclusion of the value of hematocrit or hemoglobin, achieving initial complete blood platelet count monitoring and examination of these latter. The least followed were: initial dose and temporary. It follows that a good adherence was obtained from the study, but this can be improved. It is indispensable the analysis of possible barriers to adherence.

L’ingénierie de la muqueuse orale humaine (MOH) a pour but le comblement des pertes de substances suite à un traumatisme facial ou à la chirurgie des lésions malignes. Elle a aussi des applications en recherche pour élucider les mécanismes biologiques de la MO et en pharmacotoxicologie comme alternative à l’expérimentation animale. L'objectif de cette thèse était de reconstruire une MOH proche du tissu normal. À cette fin, la faisabilité du concept a d'abord été testée par co-culture de fibroblastes de la lamina propria et de cellules épithéliales de MOH dans le substrat de collagène-chitosan glycosaminoglycane, développé pour la production de peaux reconstruites. La caractérisation de la MOH reconstruite par histologie, immunohistochimie et microscopie électronique à transmission a montré la présence d’une LP équivalente avec un épithélium pluristratifié et non kératinisé très proche du tissu d’origine. Grâce à ce modèle, nous avons ensuite démontré que l’origine des fibroblastes (MO, cornée, peau) influence significativement l’épaisseur et l’ultrastructure de l'épithélium obtenu par culture de cellules épithéliales orales. Enfin, afin d'améliorer les propriétés adhésives du substrat à base collagène, nous avons ajouté au collagène, une élastine-like recombinante (ELR) contenant le tri-peptide d’adhésion cellulaire, RGD, et produit un nouveau substrat bicouche, poreux par lyophilisation et recouvert d’une couche fibreuse par électrofilage. Ces substrats ont été caractérisés par porosimétrie au mercure, microscopie électronique à balayage et essais mécaniques. Nous avons démontré l’effet stimulant de ELR sur la prolifération des fibroblastes et des cellules épithéliales / Tissue engineered human oral mucosa has the potential to fill tissue deficits caused by facial trauma or malignant lesion surgery. It can also help elucidate the biology of oral mucosa and serve as an alternative to in vivo testing of oral care products. The aim of this thesis was to construct a tissue engineered full-thickness human oral mucosa closely mimicking the native tissue. To this end, the feasibility of the concept was tested by co-culturing fibroblasts and epithelial cells isolated from normal human oral mucosa biopsies in a collagen-glycosaminoglycan-chitosan scaffold, developed in our laboratory to construct a skin equivalent. An oral mucosal equivalent closely mimicking the native one was obtained and characterized by histology, immunohistochemistry and transmission electron microscopy. Using the same model, the influence of mesenchymal cells on oral epithelial development was investigated by culturing epithelial cells on lamina propria, corneal stroma and dermal equivalents. They were found to significantly influence the thickness and the ultrastructure of the epithelium. Finally, in order to improve the adhesiveness of conventional scaffolds, an elastin-like recombinamer (ELR) containing the cell adhesion tripeptide, RGD, was used in the production of novel bilayer scaffolds employing lyophilization and electrospinning. These scaffolds were characterized by mercury porosimetry, scanning electron microscopy and mechanical testing. In vitro tests revealed positive contribution of ELR on the proliferation of both fibroblasts and epithelial cells. It was thus possible to construct a viable oral mucosa equivalent using the principles of tissue engineering