Introdução: Apesar de todos os esforços, as taxas de mortalidade na sepse ainda são inaceitavelmente altas, por isso, é importante a busca por novos tratamentos. O óxido nítrico tem um papel fundamental na fisiopatologia da sepse e sua modulação poderia ser uma alternativa de tratamento para algumas das complicações hemodinâmicas, de perfusão tecidual e inflamatórias desta síndrome. Objetivos: Avaliar o efeito do nitroprussiato e do inibidor da iNOs (1400W) nos parâmetros hemodinâmicos, de perfusão tecidual e na inflamação, em modelo experimental de choque séptico. Métodos: Utilizou-se 20 suínos anestesiados e monitorados através do cateter de artéria pulmonar, cateter de tonometria e cateter de artéria femoral. Eles foram randomizados e tratados da seguinte maneira. Sham - somente anestesia; Choque - anestesia, infusão de bactérias (E.coli, 4,5x109ufc/mL) e tratamento padrão (fluidos e noradrenalina, guiados pela PVC, PAM e SvO2); NO/iNOs mesmos tratamentos do Choque, associado ao tratamento específico com nitroprussiato e inibidor da iNOs. Foram avaliados parâmetros hemodinâmicos, de perfusão tecidual, ventilatórios, gasométricos e inflamatórios a cada 1 hora, a partir do Tbasal até 240 minutos. Resultados: Verificou-se alterações clínicas características da sepse, após a infusão de bactérias, como taquicardia, hipotensão arterial, depressão miocárdica, hipertensão pulmonar, aumento do lactato, comprometimento da perfusão tecidual regional e indução das citocinas pró-inflamatórias. A administração do nitroprussiato associado ao inibidor da iNOs ao grupo NO/iNOs, promoveu melhora significante em relação ao grupo Choque, com aumento do IC (6,0 ± 1,9 vs 4,1 ± 2,3 e p<0,024), da FE (31 ± 13 vs 17 ± 6 e p<0,001), do ITSVE (30 ± 8 vs 20 ± 9 e p<0,026) e do IVS (35 ± 13 vs 24 ± 11 p< 0,033) e diminuição da PAP (40 ± 6 vs 48 ± 6 p<0,001) e do IRVP (460 ± 148 vs 906 ± 405 p<0,001). A perfusão tecidual melhorou, com diminuição do PCO2 intestinal (83 ± 11 vs 94 ± 16 p<0,041), diferença entre o PCO2 intestinal/ arterial (38 ± 8 vs 55 ± 27 e p< 0,039) e aumento do pH intestinal (7,07 ± 0,06 vs 6,99 ± 0,09 p< 0,032), SvO2 (79 ± 6 vs 65 ± 12 p<0,002) e DU (167 ± 89 vs 66 ± 45 p<0,001). Houve melhora da são2 (97 ± 2 vs 93 ± 7 p< 0,027) e da IL1-&beta; (340 ± 147 vs 1306 ± 238 e p< 0,001).Discussão: o tratamento proposto melhorou a função cardíaca, oxigenação, perfusão tecidual e inflamação sem apresentar efeitos adversos. Conclusão: O modelo proposto foi representativo da sepse clínica e o tratamento com nitroprussiato e inibidor da iNOs melhorou a função do miocárdio, a hemodinâmica pulmonar, a perfusão tecidual e modulou a resposta inflamatória. / Introduction: Despite all efforts, the mortality rates in sepsis are still unacceptably high, so it is important to search for new treatments. Nitric oxide plays a key role in the pathophysiology of sepsis and its modulation could be an alternative treatment for some hemodynamic, tissue perfusion and inflammatory complications of this syndrome. Objectives: Evaluate the effect of nitroprusside and iNOs inhibitor (1400W) on hemodynamic, tissue perfusion and inflammation parameters, in an experimental model of septic shock. Methods: We used 20 anesthetized pigs and monitored them via the pulmonary artery catheter, tonometry catheter and the femoral artery catheter. They were randomized and treated as follows. Sham - anesthesia only; Shock - anesthesia, infusion of bacteria (E.coli, x109ufc/mL 4.5) and standard treatment (fluids and norepinephrine, guided by CVP, MAP and SvO2) NO/iNOs - same treatments of Shock, associated to specific treatment with iNOs inhibitor and nitroprusside. We evaluated hemodynamic, tissue perfusion, ventilation, blood gas and inflammatory parameters every 1 hour from Tbasal up to 240 minutes. Results: There were clinical changes typical of sepsis, after the infusion of bacteria, such as tachycardia, hypotension, myocardial depression, pulmonary hypertension, increase of lactate, impairment of regional tissue perfusion and induction of pro inflammatory cytokines. The administration of nitroprusside associated with the iNOs inhibitor to the NO/iNOs group, caused a significant improvement in relation to the Shock group, with increase of CI (6.0 ± 1.9 vs. 4.1 ± 2.3 p <0.024), EF (31 ± 13 vs 17 ± 6 p <0.001), LVSWI (30 ± 8 vs 20 ± 9 p <0.026) and SVI (35 ± 13 vs 24 ± 11 p <0.033) and decrease of PAP (40 ± 6 vs 48 ± 6 p <0.001) and PVRI (460 ± 148 vs 906 ± 405 p <0.001). The tissue perfusion improved, with a decrease of intestinal PCO2 (83 ± 11 vs 94 ± 16 p <0.041), intestinal/arterial PCO2 gap (38 ± 8 vs 55 ± 27 p <0.039) and increase of intestinal pH (7.07 ± 0.06 vs 6, 99 ± 0.09, p <0.032), SvO2 (79 ± 6 vs 65 ± 12 p <0.002) and urinary output (167 ± 89 vs 66 ± 45 p <0.001). There was improvement in SaO2 (97 ± 2 vs 93 ± 7 p <0.027) and IL1-&beta; (340 ± 147 vs. 1306 ± 238 p <0.001). Discussion: The proposed treatment improved cardiac function, oxygenation, tissue perfusion and inflammation without producing adverse effects. Conclusion: The proposed model was representative of clinical sepsis and the treatment with nitroprusside and iNOs inhibitor improved myocardial function, pulmonary hemodynamics, tissue perfusion and modulated the inflammatory response.

Sepsis remains a severe issue in critically ill patients. Adjunctive therapies might play important role to decrease morbidity and mortality. The aim of this thesis is to investigate new adjunctive therapies role in the treatment of sepsis and septic shock. / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished

Parmi les facteurs intervienant dans la régulation et le maintien du fonctionnement d'organes, le système nerveux autonome et la microcirculation jouent un rôle prépondérant. Chez les patients critiques, comme les patients en sepsis, des altérations de la balance sympatho-vagale et de la perfusion tissulaire peuvent survenir et avoir des conséquences majeures en matière de morbidité et mortalité. La mise en oeuvre de méthodes de détection précoces de ces perturbations pourrait donc contribuer à améliorer la survie des patients à risque. En effet, le suivi des paramètres hémodynamiques, comme classiquement réalisé lors de réanimation, peut s'avérer insuffisant pour détecter des altérations de perfusion tissulaire : lors de sepsis, des altérations microcirculatoires peuvent persister en dépit de la normalisation des paramètres macrocirculatoires et sont associées à un mauvais pronostic. Eu égard à la présence de dysfunctions microcirculatoires et du système nerveux autonome chez les patients critiques, ce travail de recherche s'est proposé d'évaluer l’impact de modulateurs du système sympathique sur la balance sympatho-vagale et la microcirculation. Pour ce faire, nous avons travaillé avec des modèles animaux et des animaux admis en centre hospitalier universitaire vétérinaire. Le suivi du système nerveux autonome s'est basé sur un nouvel index de mesure du tonus parasympathique (Parasympathetic Tone Activity ou PTA). En parallèle, la microcirculation a été évaluée par vidéomicroscopie (SDF, Sidestream Dark Field imaging). L'index PTA a démontré une performance correcte pour prédire les réactions hémodynamiques chez les chiens anesthésiés. Il a aussi permis de détecter une altération de la balance sympathique chez les chevaux admis pour une chirurgie de colique ainsi qu’une altération de la microcirculation en dépit des manoeuvres de réanimation. Les études précliniques sur l’impact de la perfusion d’esmolol et de dexmédétomidine dans un modèle porcin septique ont montré que, malgré leurs effets hémodynamiques potentiels, ces agents n’ont pas eu d’effet négatif sur la microcirculation. Ainsi, les résultats de ce travail suggèrent un effet bénéfique des modulateurs du système nerveux sympathique sur la microcicultion mais nécessite d'être confirmé à plus grande échelle / Among the factors involved in the regulation and maintenance of the organs’ functioning, the autonomic nervous system and the microcirculation play a preponderant role. In critical patients, such as septic patients, alterations in the sympathovagal balance and tissue perfusion may occur and have major consequences of morbidity and mortality. The implementation of early detection methods for these disturbances could therefore contribute to improve the survival of patients at risk. Indeed, the monitoring of hemodynamic parameters, as conventionally performed during resuscitation, may be insufficient to detect tissue perfusion alterations: during sepsis, microcirculatory changes may persist despite the normalization of macrocirculatory parameters and are associated with a bad prognosis. With regard to the presence of microcirculatory dysfunctions and autonomic nervous system alterations in critical patients, this research project proposed to evaluate the impact of modulators of the sympathetic system on the sympatho-vagal balance and microcirculation. In order to achieve this, we worked on animal models and animals admitted to the faculty’s veterinary hospital center. Monitoring of the autonomic nervous system was based on a new Parasympathetic Tone Activity (PTA) index. In parallel, the microcirculation was evaluated by videomicroscopy (SDF, Sidestream Dark Field imaging). The PTA index demonstrated a good performance in predicting hemodynamic reactions in anesthetized dogs. It also detected disturbances of the sympathetic balance in horses admitted for colic surgery as well as an alteration of microcirculation despite resuscitation maneuvers. Preclinical studies on the impact of esmolol and dexmedetomidine infusion in a septic swine model showed that, despite their potential hemodynamic effects, these agents did not have a negative effect on the microcirculation. Thus, these findings suggest a beneficial effect of the modulators of the sympathetic nervous system on the microcicultion, however, these resutls should be confirmed on a larger scale

Som svar på bakteriellt orsakade systemiskainfektioner och sepsis frisätts prohormonet prokalcitonin (PCT) till blodbanan.Analys av plasma-PCT (P-PCT) kan utföras med reagenset Elecsys BRAHMS PCT ianalysmodulerna cobas® e602 och e411från Roche Diagnostics.Analysprincipen är electrochemiluminiscence som bygger på immunanalys avsandwichprincip. Syftet med föreliggande studie var att verifiera metoden föranalys av P-PCT på Roche cobas® e602 och e411 med Elecsys BRAHMS PCT(ThermoFischer) samt att göra en hållbarhetsstudie av analyten ioriginalprovröret. Verifieringen gjordes genom mätning av repeterbarhet ochprecision, samt jämförelse av analysresultat från patientprover mot ett annatlaboratorium som använder samma analysmetod. Hållbarhetsstudien gjordes genomanalys av fem patientprover under olika tidsintervall 0-24 timmar efterprovtagning. Resultaten av repeterbarhetsstudien gavvariationskoefficientvärdet (CV) 3,5 % på Roche cobas® e602 medkontrollmaterial nivå 1 (åsatt värde 0,53 µg/L) och CV 1,3 % för kontrollmaterialnivå 3 (åsatt värde 24,5 µg/L). På Roche cobas e411 blev CV 2,2 % för nivå 1och 1,6 % för nivå 3. Precisionsstudien gav mellanliggande imprecisions CV-värdenmellan 1,2–1,9 % (Kontrollmaterial nivå 1 och 3). Patientjämförelserna visadeett linjärt samband (r&gt;0,99). Bias tenderade att vara högre vidanalysresultat &gt;20 µg/L. Hållbarhetsstudien resulterade i en obetydlig minskningav PCT koncentrationen från omedelbar analys (0,73; 57,7; 2,4; 0,94; 0,27 µg/L)och efter 24 timmar (0,70; 53,69; 2,21; 0,73; 0,24 µg/L). Repeterbarheten ochprecisionen för samtliga instrument bedömdes vara god. Patientjämförelsernavisade på ett tydligt linjärt samband med låg spridning, både vid analys iKalmar och i Linköping. Hållbarhetsstudien visade acceptabel hållbarhet avanalyten i originalprovröret. Metoden anses kunna införas på kliniskt kemiskalaboratorier vid Klinisk kemi och transfusionsmedicin, Landstinget i Kalmar län. / In response to bacterial systemic infections and sepsis, the prohormone procalcitonin (PCT) is released to the bloodstream. PCT levels in plasma can be measured using Elecsys BRAHMS PCT reagent with cobas® immunoanalyzer modules e602 and e411 from Roche Diagnostics. The test principle is electrochemiluminiscence immunoassay. The aim of this study was to verify the method for measuring plasma levels of PCT with Roche cobas® e602 and e411 using Elecsys BRAHMS PCT as well as to do a sustainability study of the analyte in the original sample tube. The verification was done by measurements of repeatability and precision, and a comparison of assay results from patient samples against another laboratory using the same method. The sustainability study was done by analyzing five patient samples during different time intervals 0-24 hours after sampling. The repeatability study gave coefficient of variations (CV %) values 3.5 % and 2.2 % with Roche cobas® e602 and 1.3 % and 1.6 % with Roche cobas® e411 using quality control level 1 (affixed value 0,53 µg/L) and level 3 (affixed value 24,5 µg/L) respectively. The precision study gave CV% values between 1.2-1.9 % (quality control level 1 and 3). The patient comparison study showed linear regression (r&gt;0,99). Bias tended to be higher on assay results &gt;20 µg/L. The sustainability study resulted in a slight decrease of the plasma PCT level from immediate analysis (0.73; 57.78; 2.41; 0.94; 0.27 µg/L) to analysis after 24 hours (0.70; 53.69; 2.21; 0.73; 0.24 µg/L). The repeatability and precision was considered to be good. Patient comparisons showed a clear linear relationship with little distribution between the values, both in Kalmar and in Linköping. The sustainability study showed an acceptable sustainability of the analyte in the original sample tube. This method is considered accurate and will be introduced to the laboratories of Clinical Chemistry and Transfusion Medicine at county council of Kalmar.

Le choc septique, première cause de mortalité intra hospitalière en France, comporte deux phases chronologiques. Lors de la première phase, la mortalité est essentiellement liée aux altérations macro et micro-circulatoires et aux défaillances d’organes associées. Puis une phase d’immunodépression acquise peut suivre et rendre les patients plus sensibles aux infections nosocomiales aggravant la mortalité. Avant les années 2000, il était admis que la physiopathologie du sepsis était liée à un état pro-inflammatoire massif. Cependant, chez l’homme, l’échec voire l’effet délétère des thérapeutiques anti-inflammatoires a conduit la communauté scientifique à changer progressivement de paradigme. A partir des années 2000 le glissement des patients de l’état pro-inflammatoire vers un état anti-inflammatoire immunosuppresseur (immunoparalysie) a été démontré. En réalité, ces deux événements, schématiquement présentés de manière successive, se produisent concomitamment et coexistent chez le patient. La cachexie, une autre conséquence de l’augmentation précoce des médiateurs de l’inflammation lors du choc septique, est un facteur de morbidité supplémentaire chez l’homme. Aucun modèle animal de cachexie post-septique n’a été décrit à ce jour. Ce travail a consisté à développer des modèles murins de choc septique et de cachexie post-septique qui miment les différentes phases de la maladie humaine et en particulier l’immunoparalysie. La perte de poids observée nous a amené à nous interroger sur les effets du sepsis sur le muscle. Enfin nous avons évalué dans ces modèles l’expression d’AG (ghréline acylée) et UAG (ghréline non acylée), deux facteurs pronostics et anti-cachectisants / During sepsis, the organism is subjected to an infection. Its first immunological response will be an inflammation which is the source of numerous immunological and physiological modifications.This massive inflammation will be compensated almost simultaneously: the organism set a compensatory anti-inflammatory response in order to alleviate the deleterious effects of the release of pro-inflammatory cytokines on the organ, whether they are distant or not from the infectious site. This so called beneficial response actually turns out to be a real scourge for the host. Indeed this compensatory anti-inflammatory response is sustainable and will overtake the inflammation leading to a protracted immunoparalysis. This infection-induced immunosuppression is responsible for an increase in patients’ susceptibility to secondary nosocomial infections.Another compensatory mechanism called proteolysis will be set in response to the massive inflammation. This protein breakdown induces a supply of nutrients which are essentials for the organism. The furnished amino acids originate from skeletal muscles and in case of sepsis or any inflammatory disease, the organism is overrun. Therefore, proteolysis persists, leading to an important muscle wasting, named cachexia.Setting up a murine model of sepsis induced through a cecal ligation and puncture allowed the identification of several mechanisms involved in immunoparalysis. We point out a consistent and sustainable anti-inflammatory response with a lymphocyte anergia (reduced number and proliferative ability), and an increase of the total number of regulatory T cells. We also highlighted a bacterial load-dependent and cytokines-dependent mortality following a secondary pulmonary infection with Pseudomonas aeruginosa.Thanks to this model we also characterized septic cachexia. Despite several descriptions, formal evidences of cachexia during sepsis were lacking. Thus, the important weight loss of our animals, but especially their muscular loss after 13 days and their reduced fiber cross sectional areas could be used as a basis to an investigation of ubiquitin ligases pathway, the major actors of proteolysis. Beside classical MAFbx and MuRF1, many other ubiquitin ligases were upregulated during sepsis

L'objectif de cette thèse est d'explorer l'inflammation et l'infection au niveau du transcriptome, à l'aide de la technologie des puces à ADN. Pour cela, nous avons dans un premier temps travaillé sur des données publiques. Nous avons construit une base de données de signatures transcriptionnelles annotées, et développé un logiciel modulaire d'analyse. Ce logiciel permet d'explorer aisément les données publiques en effectuant des recherches par nom de gène ou par mots-clés. Nous avons ensuite exploré la modulation temporelle de l'expression des gènes du parenchyme pulmonaire dans un modèle murin d'inflammation aiguë par injection d'acide oléique. Dans un second modèle murin d'infection par Coxiella burnetii, nous avons analysé le rôle du sexe dans la modulation de la réponse transcriptionnelle hépatique, et identifié des voies métaboliques impliquées dans le contrôle de l'infection. Dans un troisième modèle in-vitro d'infection par différentes souches du virus de la grippe, nous avons identifié une signature transcriptionnelle commune de réponse à l'infection. Par une approche bio-informatique originale, cette signature a conduit à l'identification de nouveaux anti-viraux à large spectre, dont l'efficacité a été démontrée in-vitro sur les souches utilisées pour l'analyse, et sur la souche H1N1, responsable de la dernière pandémie grippale. Enfin, nous avons analysé les modulations du transcriptome lors de pneumonies associées à la ventilation mécanique compliquant l'évolution de sujets traumatisés graves admis en réanimation. / The goal of this PhD is to explore inflammation and infection at the transcriptome level, using DNA microarrays. In order to do so, we first analyzed public data. We built a database with annotated transcriptional signatures and developed a modular analysis software to query this database. This software allows to easily explore public data with requests based on gene names or annotation keywords. We then explored the temporal modulation of lung gene expression following oleic acid injection in a murine model. In a second murine model of infection with Coxiella burnetii, we analyzed the influence of sex-related modulation in the hepatic transcriptional response after infection and identified several pathways implicated in the control of infection. In a third model of in-vitro infection with various Influenza virus strains, we identified a shared transcriptional signature in response to cell infection. Using an original in-silico methodology, this signature allowed us to identify new broad-spectrum antivirals. Efficacy of these molecules was demonstrated in-vitro against the strains used to define the signature, and also against the new pandemic H1N1 SOIV strain. Finally, we analyzed the transcriptional modulation occurring in whole blood samples from trauma patients hospitalized in intensive care unit, and whose evolution was complicated with ventilator-associated pneumonia.

Orientador: Emílio Carlos Elias Baracat / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T18:52:29Z (GMT). No. of bitstreams: 1 SaoPedro_TaisdaCosta_M.pdf: 2742388 bytes, checksum: 2d73b02a2f0669996f10824db4a4d519 (MD5) Previous issue date: 2015 / Resumo: Introdução: A sepse ainda representa a principal causa de mortalidade em crianças. As complicações e a sobrevida na sepse dependem do diagnóstico precoce, do tratamento instituído, da resposta do paciente e do sítio de infecção. Outras variáveis epidemiológicas ou clínicas podem estar envolvidas na evolução desfavorável em pacientes admitidos em unidades de tratamento intensivo pediátrico. Identificá-las pode contribuir para uma melhor orientação de protocolos atualizados de diagnóstico e tratamento da doença. Objetivo: Determinar a etiologia e as manifestações clínicas e evolutivas da sepse em crianças e adolescentes internados em unidade de terapia intensiva. Hipótese: A inclusão das vacinas pneumocócica e meningocócica no calendário básico vacinal modificou a etiologia da sepse. Mudanças no perfil epidemiológico de crianças e adolescentes com sepse e nas manifestações clínicas e evolutivas da doença interferiram no prognóstico e na sobrevida. Métodos: Estudo de coorte prospectivo e retrospectivo. Coleta de dados nos prontuários médicos de pacientes com diagnóstico de sepse internados na unidade de terapia intensiva pediátrica do Hospital Municipal Dr. Mário Gatti, em Campinas-SP, de janeiro de 2011 a dezembro de 2013. Foram estudadas e comparadas nos grupos sobrevida e óbito, as variáveis: idade, gênero, comorbidade, esquema vacinal, agente etiológico, dados clínicos à admissão e presença de complicações na evolução. Resultados: 115 pacientes fizeram parte do estudo, com média de idade de 30,5 meses. Das culturas positivas (40), os agentes infecciosos isolados mais comuns foram Staphylococcus aureus (27,5%), Klebsiella pneumoniae (17,5%), Neisseria meningitidis (12,5%), Pseudomonas aeruginosa (10%) e Escherichia coli (10%). Sepse grave predominou nos pacientes de maior idade. Na comparação das variáveis gênero, idade, presença de comorbidades, esquema vacinal e uso de antibioticoterapia prévia, não foram encontradas diferenças significativas entre os grupos sobrevida (n=100) e óbito (n=15). A presença de complicações durante a internação foi fator associado ao óbito (RCP=27,7). Houve maior número de complicações no grupo com idade maior de 36 meses (p=0,003). Perfusão periférica alterada à admissão e o diagnóstico de sepse grave mostraram-se como fatores associados às complicações. Conclusão: Staphylococcus aureus e bactérias Gram negativas predominaram como agentes etiológicos no grupo de pacientes admitidos em terapia intensiva com diagnóstico de sepse. A gravidade da sepse e a perfusão periférica alterada à admissão estiveram associadas às complicações na evolução clínica. A presença de complicações durante a internação foi fator associado ao óbito / Abstract: Background: Sepsis is still the main cause of child mortality. Complications and survival in cases of sepsis depend on previous diagnosis, the type of treatment, the patient response and the infection site. Other epidemiological or clinical variables may be involved in the unfavorable evolution in patients admitted to pediatric intensive care unit. Identify them may contribute to a better orientation of updated diagnostic protocols and treatment of the disease. Objective: Determine the etiology and clinical/evolution variables of sepsis associated with complications and death in children and adolescents admitted in intensive care unit. Hipothesis: The inclusion of pneumococcal and meningococcal vaccines in the official vaccination schedule has changed the sepsis etilogy. Changes in the epidemiology of children and adolescents with sepsis and in clinical/evolution manifestations of this disease have influenced its prognostic and survival. Methods: Prospective and retrospective cohort study. Data were collected from medical records of patients diagnosed with sepsis, assisted at the pediatric intensive care unit of Hospital Municipal Dr. Mário Gatti, in Campinas-SP, from January 2011 to December 2013. The variables age, gender, comorbidity, vaccination schedule, etiologic agent, clinical data at admission and complications during evolution were analyzed and compared in survival and death groups. Results: One hundred and fifteen patients comprised the study, with an average of 30,5 months of age. From positive cultures (40), the most common isolated infectious agents were Staphylococcus aureus (27.5%), Klebsiella pneumoniae (17.5%), Neisseria meningitidis (12.5%), Pseudomonas aeruginosa (10%) and Escherichia coli (10%). Severe sepsis was more common in older patients. There was no difference between the survival (n=100) and death (n=15) groups in the comparison of the variables gender, age, presence of comorbidities, vaccination schedule and use of previous antibiotic therapy. The presence of complications during hospitalization was a death-associated factor (RCP=27,7). There was a higher number of complications in the group with age over 36 months (p=0,003). Altered peripheral perfusion at admission and diagnosis of severe sepsis showed as factors associated with complications. Conclusion: Staphylococcus aureus and Gram-negative bacteria predominated as etiological agents in the group of patients admitted in intensive therapy with diagnosis of sepsis. Sepsis severity and altered peripheral perfusion at admission were associated with complications in clinical evolution. The presence of complications during hospitalization was a factor associated with death / Mestrado / Saude da Criança e do Adolescente / Mestra em Ciências

Les Myeloid-Derived Suppressor Cells (MDSC) sont une population hétérogène de cellules myéloïdes immatures, regroupées en deux sous-populations : les monocytiques-MDSC (M-MDSC) et les polymorphonucléaires-MDSC (PMN-MDSC). Ces cellules ont des capacités immunosuppressives et peuvent exprimer le ligand PD-L1 induisant l’anergie des lymphocytes T qui expriment le marqueur PD-1. Au cours du sepsis, divers bouleversements immunologiques surviennent, et la fonction majeure des MDSC est probablement de réguler l’hyper-inflammation en participant à l’état d’immunodépression rencontré chez les patients. Ceux-ci ont alors un risque de développer des infections secondaires, et de réactiver des virus jusque-là en latence. Notre étude a pour objectifs de mettre en évidence l’origine des MDSC dans le sepsis, et d’approfondir leurs rôles dans l’état d’immunosuppression, notamment dans la réactivation du Torque Teno Virus (TTV). Nos résultats montrent tant ex vivo qu’in vitro, que dans le sepsis, les MDSC sont produites par la moelle osseuse, sous l’influence du G-CSF et de l’IL-6. Ces cellules exprimant PD-L1, sont augmentées dans le sang très tôt dans le sepsis et persistes au cours de l’hospitalisation. L’augmentation de la charge virale du TTV est observée dans le sang périphérique des patients, mais n’est pas corrélée à la fréquence des MDSC. Ces résultats suggèrent que lors d’un sepsis, l’orage cytokinique stimule la production de MDSC exprimant PD-L1 par la moelle osseuse, qui une fois en périphérie, vont participer à l’immunosuppression générale. / Myeloid-Derived Suppressor Cells (MDSC) are a heterogeneous population of immature myeloid cell, and are regrouped in two subsets: the monocytic-MDSC (M-MDSC) and the polymorphonuclear-MDSC (PMN-MDSC). These cells have immunosuppressive capacities and mainly act on T cells. MDSC can express the ligand PD-L1 and induce PD-1 expressing-T cells exhaustion. During sepsis, several immunological changes occur, and MDSC probably downregulate the hyper-inflammatory state, contributing to the immunosuppression phase encountered in patients after a sepsis. Immunocompromised patients can develop secondary infections, and reactivate latent virus. The aims of our study were to highlight the origin of MDSC in sepsis, and to explore their roles in the immunosuppression state, especially in the Torque Teno Virus (TTV) reactivation. Our results show, both ex vivo and in vitro, that in sepsis, MDSC originate from bone marrow are induced by G-CSF and IL-6. These PD-L1 expressing-cells are increased in peripheral blood very early in sepsis, and persist during hospitalization. These MDSC are able to inhibit T cells in vitro. The increase of TTV viral load is observed in peripheral blood of patients but is not correlated with MDSC frequencies. These results suggest that during sepsis, the cytokine storm boosts PD-L1 expressing MDSC’s production by bone marrow, which contribute in peripheral blood to the immunosuppression

La forme non musculaire de la kinase de la chaine légère de la myosine (MLCKnm) est une kinase principalement exprimée par les cellules endothéliales dont le rôle principal est de phosphoryler la chaine légère de myosine. Cette phosphorylation modifie la conformation des têtes de myosine, augmente l’interaction actine/myosine, et induit une rétraction des cellules endothéliales. Ce processus augmente la perméabilité de la barrière endothéliale. L’activation de MLCKnm permet l’infiltration de cellules inflammatoires en réponse à certains stimuli dont le lipopolysaccharide (LPS) bactérien. Dans ce modèle expérimental de sepsis, la déficience de MLCKnm dans un modèle murin protège les souris injectées avec du LPS, associée à une prévention des stress oxydant et nitrosant ainsi que de l’activation de voies de signalisation inflammatoire. Cependant les mécanismes moléculaires mis en jeu ne sont pas totalement connus. Dans le contexte inflammatoire, le syndrome d’apnées/hypopnées obstructives du sommeil, caractérisé par une obstruction des voies aériennes lors du sommeil menant à une hypoxie intermittente (HI), partage certaines caractéristiques dans l’activation inflammatoire observée lors du sepsis. L’HI modifie le métabolisme des cellules endothéliales en diminuant la biodisponibilité du monoxyde d’azote, augmentant le stress oxydant ainsi que la production de certains facteurs inflammatoires. A long terme, une réponse inflammatoire systémique est observée augmentant les risques d’athérosclérose. L’objectif de ce travail est d’étudier l’implication de MLCKnm dans l’inflammation vasculaire dans deux modèles physiopathologiques, induits par le LPS et l’HI. / Non muscular myosin light chain kinase (nmMLCK) is aprotein mainly expressed by endothelial cells whose roleis to phosphorylate myosin light chain. This phosphorylation modifies the conformation of myosin heads, increasing actin/myosin interaction, and inducing endothelial cells retraction. This process increases endothelial barrier permeability. The activation of nmMLCK increases inflammatory cell infiltration in response to several stimuli such as the bacterial lipopolysaccharide (LPS). In this experimental model of sepsis, nmMLCK deficiency in a murine model protects mice injected with LPS, associated with oxidative and nitrative stresses prevention as well as inflammatory pathway inhibition. However, molecular mechanisms are not fully known. In this inflammatory context, obstructive sleep apnea hypopnea syndrome, characterized by obstruction of upper airway during sleep leading to intermittent hypoxia (IH), share several characteristics in inflammatory activation observed during sepsis. IH modifies the metabolism of endothelial cells decreasing nitric oxide bioavailability, increasing oxidative stress aswell as inflammatory mediators. Long-term, systemic inflammatory response is observed increasing atherosclerosis risk. The objective of this work is to study the implication of nmMLCK in vascular inflammation in two pathophysiological models induced by LPS and IH.

Background: Inhaled carbon monoxide (CO) appears to have beneficial effects on endotoxemia-induced impairment of hypoxic pulmonary vasoconstriction (HPV). This study aims to specify correct timing of CO application, it’s biochemical mechanisms and effects on inflammatory reactions. Methods: Mice (C57BL/6; n = 86) received lipopolysaccharide (LPS, 30 mg/kg) intraperitoneally and subsequently breathed 50 ppm CO continuously during defined intervals of 3, 6, 12 or 18 h. Two control groups received saline intraperitoneally and additionally either air or CO, and one control group received LPS but breathed air only. In an isolated lung perfusion model vasoconstrictor response to hypoxia (FiO2 = 0.01) was quantified by measurements of pulmonary artery pressure. Pulmonary capillary pressure was estimated by double occlusion technique. Further, inflammatory plasma cytokines and lung tissue mRNA of nitric-oxide-synthase-2 (NOS-2) and heme oxygenase-1 (HO-1) were measured. Results: HPV was impaired after LPS-challenge (p < 0.01). CO exposure restored HPV-responsiveness if administered continuously for full 18 h, for the first 6 h and if given in the interval between the 3rd and 6th hour after LPS-challenge (p < 0.05). Preserved HPV was attributable to recovered arterial resistance and associated with significant reduction in NOS-2 mRNA when compared to controls (p < 0.05). We found no effects on inflammatory plasma cytokines. Conclusion: Low-dose CO prevented LPS-induced impairment of HPV in a time-dependent manner, associated with a decreased NOS-2 expression.