INTRODUÇÃO: Apesar do contínuo progresso no tratamento e suporte clínico a sepse continua sendo uma das principais causas de morbidade e mortalidade nas unidades de terapia intensiva, com desfechos semelhantes ao longo dos últimos 50 anos. A suscetibilidade à infecção grave no recém-nascido é parcialmente devida à imaturidade do sistema imune inato associado à mínima em exposição antigênica in utero e à ação ineficaz das células T efetoras e das célula B. Embora a ativação do sistema imune inato por padrões de reconhecimento (PRR) como os dos receptores Toll-like (TLR) tenham sua importância amplamente reconhecida nos últimos anos, seu comportamento frente a uma infecção in vivo ainda não foi completamente compreendido. Neste trabalho nós analisamos a expressão dos TLR-2 e TLR-4 em células apresentadoras de antígeno em recém-nascidos com e sem sepse. CAUSUÍSTICA E MÉTODO: Trata-se de um estudo prospectivo realizado no período entre fevereiro de 2011 e janeiro de 2013 onde foram incluídos quarenta e cinco recém-nascidos a termo, sem malformação congênita, admitidos na Unidade de Cuidados Intensivos Neonatal do Instituto da Criança-HCFMUSP e divididos em grupos 1 e 2. O grupo 1 consistiu em 27 recém-nascidos com diagnóstico clínico e laboratorial de sepse tardia enquanto que o grupo 2 foi composto por 18 recém-nascidos sem quadro séptico vigente. As citocinas foram determinadas por teste de CBA em sangue periférico. A expressão e MFI dos TLR-2 e TLR-4 foi determinado por imunofenotipagem em APCs e linfócitos no sangue periférico total através de análise pelo citômetro de fluxo BD FACSDiva. RESULTADOS: Os dados clínicos foram semelhantes entre os grupos 1 e 2, exceto para o estado infeccioso. Microrganismos foram identificados em 37 % no grupo 1 e estes tiveram níveis mais elevados de citocinas pró-inflamatórias (IL-8, IL-6, IL-1beta) e de citocina anti-inflamatória (IL-10). Nas células dendríticas, a expressão de TLR-2 e 4 foi semelhante entre os grupos enquanto que houve menor expressão nos pacientes infectados da molécula co-estimuladora CD86 (p < 0,05) e expressão semelhante de CD1a e CD80 em relação aos RN não infectados. No monócito, o MFI para TLR-2 e a freqüência de expressão do TLR-4 foi maior no grupo 1 (p = 0,01). Apesar da frequência de linfócitos totais ter sido mais baixa no grupo 1 (p = 0,002), não foi observada diferença quanto as suas subpopulações exceto em relação a maior frequência de LT efetor no grupo infectado com menor expressão da molécula CD28. Houve maior frequência de LB ativados no grupo 1 enquanto que a população total e as demais subpopulações foram semelhantes em número, moléculas de ativação e na expressão dos TLR-2 e 4 em ambos os grupos. CONCLUSÃO: Este estudo analisou a resposta imune inata no recém-nascido com e sem sepse. As IL-6, IL-8 e IL-10 foram bons indicadores desta doença. Recém-nascidos sépticos, que dependem quase exclusivamente do sistema imune inato, apresentaram pouca resposta in vivo na ativação de células dendríticas e monócitos propiciando uma resposta imune deficiente e maior susceptibilidade à infecção / INTRODUCTION: Despite continuous progress in the clinical treatment and other supportive care therapies, sepsis remains a leading cause of morbidity and mortality in the intensive care unit with similar outcome throughout the past 50 years. The susceptibility to severe infection is partially due to newborn immature innate immune system associated to minimal in utero antigen exposure and effector T and B cell impaired function. Although the importance of pattern recognition domains such as Toll-like receptors (TLR) in the innate immune system activation has been fully acknowledged within the last few years its behavior in front of an in vivo infection scenario is still not completely understood. Here we analyzed the TLR-2 and TLR-4 expression in antigen-presenting cell in healthy and septic newborns. PATIENTS AND METHODS: This prospective study was conducted during the period from February 2011 until January 2013 at Sao Paulo University, Sao Paulo, Brazil. Forty-five term newborns without congenital malformation were included from the Newborn Intensive Care Unit at Children\'s Hospital. As group 1, 27 newborns who had clinical and laboratory diagnostic of late onset sepsis were included while 18 newborns were evaluated in a non-septic status and were included at group 2. Cytokines were measured by cytometric bead array in peripheral blood. TLR-2 and TLR-4 expression and MFI were determined by immunophenotyping at peripheral whole blood in APC cells and lymphocytes and analyzed on a BD FACSDiva flow cytometer. RESULTS: Clinical data was similar between septic and non-septic groups except for the infectious status. Group 1 had microorganisms identified in 37 % septic newborns associated with higher levels of pro-inflammatory (IL-8, IL-6, IL-1beta) and anti-inflammatory interleukins (IL-10). When it comes to dendritic cells, the expression of TLR-2 and 4 was similar between groups whereas there was lower expression of co-molecule CD86 (p < 0,05) and similar expression of CD1a and CD80 between infected and non-infected patients. At monocytes, the MFI for TLR-2 and the frequency of TLR-4 expression was higher in infected newborn (p=0,01). There were lower levels of total lymphocytes in infected patients (p=0,002) but no difference was observed in T cells subtypes frequency except for higher levels of effector T cell in infected group with lower expression of CD28 molecule. Group 1 had higher levels of activated B cell whereas total population and the other subsets were similar in number, activation molecules and TLR-2 and 4 expressions in both groups. CONCLUSION: This study investigated the innate immune response in septic and non-septic newborn. Interleukin levels 6, 8 and 10 were good indicators of sepsis. Septic newborns, which count most exclusively with innate immune system, had little in vivo response at dendritic cell and monocyte activation leading to an impaired immune response and increased susceptibility to infection

INTRODUÇÃO: Apesar do contínuo progresso no tratamento e suporte clínico a sepse continua sendo uma das principais causas de morbidade e mortalidade nas unidades de terapia intensiva, com desfechos semelhantes ao longo dos últimos 50 anos. A suscetibilidade à infecção grave no recém-nascido é parcialmente devida à imaturidade do sistema imune inato associado à mínima em exposição antigênica in utero e à ação ineficaz das células T efetoras e das célula B. Embora a ativação do sistema imune inato por padrões de reconhecimento (PRR) como os dos receptores Toll-like (TLR) tenham sua importância amplamente reconhecida nos últimos anos, seu comportamento frente a uma infecção in vivo ainda não foi completamente compreendido. Neste trabalho nós analisamos a expressão dos TLR-2 e TLR-4 em células apresentadoras de antígeno em recém-nascidos com e sem sepse. CAUSUÍSTICA E MÉTODO: Trata-se de um estudo prospectivo realizado no período entre fevereiro de 2011 e janeiro de 2013 onde foram incluídos quarenta e cinco recém-nascidos a termo, sem malformação congênita, admitidos na Unidade de Cuidados Intensivos Neonatal do Instituto da Criança-HCFMUSP e divididos em grupos 1 e 2. O grupo 1 consistiu em 27 recém-nascidos com diagnóstico clínico e laboratorial de sepse tardia enquanto que o grupo 2 foi composto por 18 recém-nascidos sem quadro séptico vigente. As citocinas foram determinadas por teste de CBA em sangue periférico. A expressão e MFI dos TLR-2 e TLR-4 foi determinado por imunofenotipagem em APCs e linfócitos no sangue periférico total através de análise pelo citômetro de fluxo BD FACSDiva. RESULTADOS: Os dados clínicos foram semelhantes entre os grupos 1 e 2, exceto para o estado infeccioso. Microrganismos foram identificados em 37 % no grupo 1 e estes tiveram níveis mais elevados de citocinas pró-inflamatórias (IL-8, IL-6, IL-1beta) e de citocina anti-inflamatória (IL-10). Nas células dendríticas, a expressão de TLR-2 e 4 foi semelhante entre os grupos enquanto que houve menor expressão nos pacientes infectados da molécula co-estimuladora CD86 (p < 0,05) e expressão semelhante de CD1a e CD80 em relação aos RN não infectados. No monócito, o MFI para TLR-2 e a freqüência de expressão do TLR-4 foi maior no grupo 1 (p = 0,01). Apesar da frequência de linfócitos totais ter sido mais baixa no grupo 1 (p = 0,002), não foi observada diferença quanto as suas subpopulações exceto em relação a maior frequência de LT efetor no grupo infectado com menor expressão da molécula CD28. Houve maior frequência de LB ativados no grupo 1 enquanto que a população total e as demais subpopulações foram semelhantes em número, moléculas de ativação e na expressão dos TLR-2 e 4 em ambos os grupos. CONCLUSÃO: Este estudo analisou a resposta imune inata no recém-nascido com e sem sepse. As IL-6, IL-8 e IL-10 foram bons indicadores desta doença. Recém-nascidos sépticos, que dependem quase exclusivamente do sistema imune inato, apresentaram pouca resposta in vivo na ativação de células dendríticas e monócitos propiciando uma resposta imune deficiente e maior susceptibilidade à infecção / INTRODUCTION: Despite continuous progress in the clinical treatment and other supportive care therapies, sepsis remains a leading cause of morbidity and mortality in the intensive care unit with similar outcome throughout the past 50 years. The susceptibility to severe infection is partially due to newborn immature innate immune system associated to minimal in utero antigen exposure and effector T and B cell impaired function. Although the importance of pattern recognition domains such as Toll-like receptors (TLR) in the innate immune system activation has been fully acknowledged within the last few years its behavior in front of an in vivo infection scenario is still not completely understood. Here we analyzed the TLR-2 and TLR-4 expression in antigen-presenting cell in healthy and septic newborns. PATIENTS AND METHODS: This prospective study was conducted during the period from February 2011 until January 2013 at Sao Paulo University, Sao Paulo, Brazil. Forty-five term newborns without congenital malformation were included from the Newborn Intensive Care Unit at Children\'s Hospital. As group 1, 27 newborns who had clinical and laboratory diagnostic of late onset sepsis were included while 18 newborns were evaluated in a non-septic status and were included at group 2. Cytokines were measured by cytometric bead array in peripheral blood. TLR-2 and TLR-4 expression and MFI were determined by immunophenotyping at peripheral whole blood in APC cells and lymphocytes and analyzed on a BD FACSDiva flow cytometer. RESULTS: Clinical data was similar between septic and non-septic groups except for the infectious status. Group 1 had microorganisms identified in 37 % septic newborns associated with higher levels of pro-inflammatory (IL-8, IL-6, IL-1beta) and anti-inflammatory interleukins (IL-10). When it comes to dendritic cells, the expression of TLR-2 and 4 was similar between groups whereas there was lower expression of co-molecule CD86 (p < 0,05) and similar expression of CD1a and CD80 between infected and non-infected patients. At monocytes, the MFI for TLR-2 and the frequency of TLR-4 expression was higher in infected newborn (p=0,01). There were lower levels of total lymphocytes in infected patients (p=0,002) but no difference was observed in T cells subtypes frequency except for higher levels of effector T cell in infected group with lower expression of CD28 molecule. Group 1 had higher levels of activated B cell whereas total population and the other subsets were similar in number, activation molecules and TLR-2 and 4 expressions in both groups. CONCLUSION: This study investigated the innate immune response in septic and non-septic newborn. Interleukin levels 6, 8 and 10 were good indicators of sepsis. Septic newborns, which count most exclusively with innate immune system, had little in vivo response at dendritic cell and monocyte activation leading to an impaired immune response and increased susceptibility to infection

Objetivos: Avaliar a utilidade dos mediadores pró-inflamatórios (TNF-alfa, IL-1 beta e IL-6), dos mediadores antiinflamatórios (IL-10 e IL-1Ra) e da Proteína C reativa (PCR) para o diagnóstico na sepse neonatal; verificar se os valores séricos isolados ou a relação entre IL-6 e IL-1Ra têm valor preditivo de gravidade, na evolução clínica da doença; determinar se a homeostase entre os mediadores pró-inflamatórios e antiinflamatórios e a PCR definem o prognóstico da doença. Casuística e métodos: Foram incluídos no estudo 31 recém-nascidos (RN) internados na UCINE ou no Hospital Universitário com diagnóstico de sepse, baseado em critérios clínicos e laboratoriais. Os RN com diagnóstico de sepse foram subdivididos em dois grupos de acordo com a evolução clínica: grupo sepse: os que tiveram boa evolução e grupo sepse grave, os que tiveram evolução complicada por choque séptico e/ou CIVD e/ou FMOS e/ou óbito. Além dos exames de rotina para sepse, forma mensurados nos dias 0, 3 e 7 de evolução a partir do diagnóstico, os níveis séricos de TNF-alfa, IL-1 beta, IL-6, IL-10 e IL-1Ra. Resultados: Na análise evolutiva geral, todos os mediadores inflamatórios apresentaram mensuração elevada no dia do diagnóstico (dia 0), com decréscimo dos valores no decorrer do tempo. Entre os mediadores pró-inflamatórios, a TNF-alfa, a IL-6 e a IL-1 beta se mostraram adequados para o diagnóstico, no entanto para o seguimento, a melhor foi a IL-6. Entre os mediadores antiinflamatórios a IL-10 seguiu os padrões dos mediadores próinflamatórios acompanhando a resolução do processo séptico, enquanto a IL-1Ra apresentou decréscimos até o 3º dia e permaneceu estável até o 7º dia caracterizando a perpetuação da ação antiinflamatória desta citocina. Quanto às relações entre mediadores pró-inflamatórios e antiinflamatórios (relação IL-6/IL-1Ra e IL-6/(IL-6 + IL-1Ra) observamos que a IL-6/IL-1Ra apresentou relação com a evolução do processo séptico, mostrando inicialmente predomínio da ação próinflamatória no dia 0 e antiinflamatória no dia 7. A PCR acompanhou de forma muito semelhante as curvas da TNF-alfa, L-6 e IL-10. Quando se subdividiu a casuística em grupos, sepse e sepse grave, observamos que os RN com sepse com boa evolução apresentaram níveis séricos médios de TNF-alfa, IL-1 beta e IL-10 próximos aos níveis mínimos detectáveis e estas citocinas nos RN com sepse grave. / Objectives - To evaluate the utility of the pro-inflammatory mediators (TNF-alfa, IL1-beta, and IL-6), the anti-inflammatory mediators (IL-10 and IL-1Ra) and C-Reactive Protein (CRP) for the diagnosis of neonatal sepsis; to verify whether the isolated seric values or the relation between IL-6 and IL-1Ra have predictive values for severity regarding the clinical outcome, and to ascertain if the homeostasis between the pro-inflammatory and anti-inflammatory mediators and CPR can define the prognosis of the disease. Patients and Methods - The study included 31 newborns (NB) admitted to the UCINE (External Neonatal Unit) or to Hospital Universitário (São Paulo University Hospital) with diagnosis of sepsis based upon clinical and laboratorial parameters. The NB with diagnosis of sepsis were further subdivided into 2 groups according to the clinical outcome: sepsis group: containing those NB who evolved to a positive outcome, and severe sepsis group, in turn composed of the NB with unsatisfactory outcomes due to complications caused by septic shock and/or DIVC and/or FMOS and/or death. On days 0, 3, and 7 following diagnosis the seric levels of TNF-alfa, IL-1 beta, IL-6, IL-10, and IL-1Ra were measured in addition to the routine sepsis workup. Results - The general follow-up analysis revealed that all the inflammatory mediators presented elevated levels at diagnosis (day 0) with a decrease of these values over time. Regarding the pro-inflammatory mediators, TNF-alfa, IL-6 and IL-1 beta were satisfactory for diagnosis, whereas IL-6 was more accurate for follow-up. In relation to the anti-inflammatory mediators, IL-10 revealed the same pattern of the pro-inflammatory mediators following the septic process resolution, whereas IL-1Ra gradually decreased until the 3rd day but hence remained stable until the 7th day, thus characterizing the continuity of the anti-inflammatory action of this cytokine. Concerning the inter-relation between the pro and anti-inflammatory mediators (IL-6/IL-1Ra relation and IL-6/(IL6+IL-1Ra)) we observed that the IL-6/IL-1Ra correlated with the septic process evolution with predominance of the proinflammatory action on day 0 and of the anti-inflammatory action on day 7. The CRP levels, we observed that in the sepsis group with satisfactory outcome on day 0 the seric values were higher than in the severe sepsis group, although on days 3 and 7 these values decreased more substantially, while in the sepsis group they increased on day 3 followed by a gradual decrease until day 7. Conclusions - The analyzed mediators were effective in the diagnosis of neonatal sepsis and also predictive of the degree of severity, mainly with regards to cytokines IL-6 and IL-1Ra. The homeostatic equilibrium/disequilibrium was correlated to the type of disease outcome: sepsis with no complications versus severe sepsis.

Objetivos: Avaliar a utilidade dos mediadores pró-inflamatórios (TNF-alfa, IL-1 beta e IL-6), dos mediadores antiinflamatórios (IL-10 e IL-1Ra) e da Proteína C reativa (PCR) para o diagnóstico na sepse neonatal; verificar se os valores séricos isolados ou a relação entre IL-6 e IL-1Ra têm valor preditivo de gravidade, na evolução clínica da doença; determinar se a homeostase entre os mediadores pró-inflamatórios e antiinflamatórios e a PCR definem o prognóstico da doença. Casuística e métodos: Foram incluídos no estudo 31 recém-nascidos (RN) internados na UCINE ou no Hospital Universitário com diagnóstico de sepse, baseado em critérios clínicos e laboratoriais. Os RN com diagnóstico de sepse foram subdivididos em dois grupos de acordo com a evolução clínica: grupo sepse: os que tiveram boa evolução e grupo sepse grave, os que tiveram evolução complicada por choque séptico e/ou CIVD e/ou FMOS e/ou óbito. Além dos exames de rotina para sepse, forma mensurados nos dias 0, 3 e 7 de evolução a partir do diagnóstico, os níveis séricos de TNF-alfa, IL-1 beta, IL-6, IL-10 e IL-1Ra. Resultados: Na análise evolutiva geral, todos os mediadores inflamatórios apresentaram mensuração elevada no dia do diagnóstico (dia 0), com decréscimo dos valores no decorrer do tempo. Entre os mediadores pró-inflamatórios, a TNF-alfa, a IL-6 e a IL-1 beta se mostraram adequados para o diagnóstico, no entanto para o seguimento, a melhor foi a IL-6. Entre os mediadores antiinflamatórios a IL-10 seguiu os padrões dos mediadores próinflamatórios acompanhando a resolução do processo séptico, enquanto a IL-1Ra apresentou decréscimos até o 3º dia e permaneceu estável até o 7º dia caracterizando a perpetuação da ação antiinflamatória desta citocina. Quanto às relações entre mediadores pró-inflamatórios e antiinflamatórios (relação IL-6/IL-1Ra e IL-6/(IL-6 + IL-1Ra) observamos que a IL-6/IL-1Ra apresentou relação com a evolução do processo séptico, mostrando inicialmente predomínio da ação próinflamatória no dia 0 e antiinflamatória no dia 7. A PCR acompanhou de forma muito semelhante as curvas da TNF-alfa, L-6 e IL-10. Quando se subdividiu a casuística em grupos, sepse e sepse grave, observamos que os RN com sepse com boa evolução apresentaram níveis séricos médios de TNF-alfa, IL-1 beta e IL-10 próximos aos níveis mínimos detectáveis e estas citocinas nos RN com sepse grave. / Objectives - To evaluate the utility of the pro-inflammatory mediators (TNF-alfa, IL1-beta, and IL-6), the anti-inflammatory mediators (IL-10 and IL-1Ra) and C-Reactive Protein (CRP) for the diagnosis of neonatal sepsis; to verify whether the isolated seric values or the relation between IL-6 and IL-1Ra have predictive values for severity regarding the clinical outcome, and to ascertain if the homeostasis between the pro-inflammatory and anti-inflammatory mediators and CPR can define the prognosis of the disease. Patients and Methods - The study included 31 newborns (NB) admitted to the UCINE (External Neonatal Unit) or to Hospital Universitário (São Paulo University Hospital) with diagnosis of sepsis based upon clinical and laboratorial parameters. The NB with diagnosis of sepsis were further subdivided into 2 groups according to the clinical outcome: sepsis group: containing those NB who evolved to a positive outcome, and severe sepsis group, in turn composed of the NB with unsatisfactory outcomes due to complications caused by septic shock and/or DIVC and/or FMOS and/or death. On days 0, 3, and 7 following diagnosis the seric levels of TNF-alfa, IL-1 beta, IL-6, IL-10, and IL-1Ra were measured in addition to the routine sepsis workup. Results - The general follow-up analysis revealed that all the inflammatory mediators presented elevated levels at diagnosis (day 0) with a decrease of these values over time. Regarding the pro-inflammatory mediators, TNF-alfa, IL-6 and IL-1 beta were satisfactory for diagnosis, whereas IL-6 was more accurate for follow-up. In relation to the anti-inflammatory mediators, IL-10 revealed the same pattern of the pro-inflammatory mediators following the septic process resolution, whereas IL-1Ra gradually decreased until the 3rd day but hence remained stable until the 7th day, thus characterizing the continuity of the anti-inflammatory action of this cytokine. Concerning the inter-relation between the pro and anti-inflammatory mediators (IL-6/IL-1Ra relation and IL-6/(IL6+IL-1Ra)) we observed that the IL-6/IL-1Ra correlated with the septic process evolution with predominance of the proinflammatory action on day 0 and of the anti-inflammatory action on day 7. The CRP levels, we observed that in the sepsis group with satisfactory outcome on day 0 the seric values were higher than in the severe sepsis group, although on days 3 and 7 these values decreased more substantially, while in the sepsis group they increased on day 3 followed by a gradual decrease until day 7. Conclusions - The analyzed mediators were effective in the diagnosis of neonatal sepsis and also predictive of the degree of severity, mainly with regards to cytokines IL-6 and IL-1Ra. The homeostatic equilibrium/disequilibrium was correlated to the type of disease outcome: sepsis with no complications versus severe sepsis.

Protein nitration is considered as a marker of reactive nitrogen species formation. Heme oxygenases (HOs) are important for the defence against oxidative stress. We evaluated the involvement of the neuronal (nNOS), the endothelial (eNOS), and the inducible (iNOS) in nitrotyrosine formation and localitzation, and both the expression and funcional significance (HO inhibition and contractility studies) of HOs in sepsis-induced muscle contractile dysfunction. Sepsis was elicited by injecting rats and transgenic mice deficient in either nNOS, eNOS, or iNOS isoforms with E.Coli lipolysaccharide (LPS). Nitrotyrosine formation and HO expressions were assessed by immunoblotting. Oxidative stress was assessed measuring protein oxidation, lipid peroxidation, and muscle glutathione. We conclude that protein tyrosine nitration occurs in normal muscles, and sepsis-mediated increase in nitrotyrosine formation is limited to the mitochondria and membrane muscle fractions. The iNOS isoform is mostly involved in nitrotyrosine formation. HOs protect normal and septic muscles from the deleterious effects of oxidants. / En un model de sepsi de disfunció diafragmàtica, s´ha avaluat el paper de les sintetases de l'òxid nítric (NOS) en la formació i localitzacio de 3-nitrotirosina, i l´expressió i significat biològic de les hemo oxigenases (HOs) (inhibidor de les HOs i estudis de contractilitat) davant l' estrès oxidatiu. La sepsi s'induí mitjançant injecció de 20 mg/kg del lipolisacàrid (LPS) d´Escherichia Coli a rates, i a ratolins deficients en les NOS induïble (iNOS), neuronal (nNOS) i endotelial (eNOS). Les proteïnes nitrificades i les HOs es van detectar amb anticossos específics. L' estrès oxidatiu s' avaluà mitjançant l' oxidació proteica, la peroxidació lipídica i el glutation muscular. Concloem que hi han proteïnes nitrificades en el múscul normal i aquestes s'incrementen durant la sepsi en les fraccions mitocondrial i membranar. L'isoforma iNOS és majorment responsable de la formació de nitrotirosina. Les HOs protegirien el múscul normal i sèptic dels efectes deleteris dels oxidants.

This Ph.D. dissertation processes and analyzes signals from the neonatal intensive care units (NICUs) for the study of maturity, systemic infection (sepsis) and the influence of immunization in the premature newborn. A special attention is payed to the electroencephalography and the breathing signal. The former is often contaminated by several sources of noise, thus methods based on the signals decomposition and optimal noise cancellation, adapted to the characteristics of the immature EEG, were proposed and evaluated objectively on real and simulated signals. By means of the EEG and delta burst analysis, detected automatically by a proposed classifier, infant's maturation and the effects of vaccination are studied. Concerning the second signal, breathing, non-linear and fractal methods are adapted to evaluate maturity and sepsis. A robustness study of estimation methods is also conducted, showing that the Hurst exponent, estimated on respiratory variability signals, is a good detector of infection.

A &#946;2-glicoproteína I (&#946;2GPI) é uma proteína de fase aguda, produzida principalmente no fígado e intestino. Os efeitos dessa proteína sobre células mononucleares foram investigados tanto em monócitos humanos de sangue periférico quanto em células promonocíticas humanas da linhagem celular ATCC THP-1. As correlações entre sua concentração plasmática e a intensidade da inflamação sistêmica foram avaliadas em humanos e em um modelo experimental de infecção sistêmica, em ratos. Nenhum efeito da &#946;2GPI foi observado sobre a resposta oxidativa de monócitos de sangue periférico durante a fagocitose de zymosan opsonisado ou de S. aureus, analisada respectivamente por quimiluminescência amplificada por luminol ou por citometria de fluxo. A &#946;2GPI estimulou a viabilidade celular e estimulou a diferenciação dos promonócitos. As células THP-1 tratadas com &#946;2GPI apresentaram adesão aumentada a placas de cultura bem como expressão aumentada de CD54 e CD14. A suplementação com &#946;2GPI foi suficiente para manter a proliferação das células THP-1 em cultura sem a adição de soro por 72h. Não houve correlações entre a concentração plasmática da &#946;2GPI e indicadores clínicos da resposta inflamatória aguda em pacientes sépticos. A concentração da &#946;2GPI não correlacionou com as concentrações plasmáticas de IL-8, SAA e PCR, que foram encontradas elevadas no sangue de pacientes com sepse. A variação da concentração plasmática de &#946;2GPI foi um fenômeno muito precoce no modelo experimental de sepse e translocação bacteriana. Nas primeiras três horas após a indução da sepse endovenosa, a concentração plasmática de &#946;2GPI diminuiu de forma dependente da intensidade de infecção. Sugere-se que efeitos muito precoces de compartimentalização associados ao sangue portal medeiem esta regulação. As concentrações mais baixas de &#946;2GPI foram observadas nos animais expostos à translocação bacteriana através da mucosa intestinal, associada a uma condição inflamatória leve. A derivação da linfa preveniu completamente a diminuição da concentração plasmática de &#946;2GPI. Em conjunto, os resultados revelaram a relevância combinada de via e de intensidade da infecção para o controle da concentração plasmática de &#946;2GPI no início na resposta inflamatória aguda. / The &#946;2-glycoprotein I (&#946;2GPI) is an acute phase protein, produced mainly in the liver and intestine. The effects of this protein upon mononuclear cells were investigated both in monocytes from human peripheral blood, and in the human promonocytic cells from the ATCC THP-1 cell line. The correlations between its plasma concentration and systemic inflammation intensity were evaluated in humans and in ad experimental model of systemic infection in rats. No &#946;2GPI effects were observed upon the oxidative response of blood monocytes during the phagocytosis of opsonized zymosan or S. aureus as analysed by luminol amplified chemiluminescence and flow cytometry. &#946;2GPI enhanced the cellular viability and stimulated the differentiation of the promonocytes. The THP-1 cells treated with &#946;2GPI presented increased adhesion to the plastic of cell culture plates as well as increased expression of CD54 and CD14 antigens. The supplementation with &#946;2GPI was sufficient to support the proliferation of THP-1 cells in serum free culture conditions for 72 h. There were no correlations between the &#946;2GPI plasma concentration and clinical parameters of the acute inflammatory response in septic patients. The &#946;2GPI concentrations didn\'t correlated with the plasma concentrations of IL-8, SAA and C reactive protein, despite these substances were found increased in the blood of patients with sepsis. The &#946;2GPI plasma concentration response was a very early phenomenon in the experimental sepsis and bacterial translocation model. The &#946;2GPI concentration decreased within the first 3h after endovenous sepsis induction, depending on the infection intensity. Very early compartment effects associated with the portal blood are suggested to mediate such regulation. The lowest &#946;2GPI concentrations were found in the animals exposed to bacterial translocation through the intestinal mucosa, associated with a mild inflammatory condition. The lymph derivation completely prevented the plasma &#946;2GPI decrease. Taken together, the results revealed the relevance of both the infection route and intensity to the control of plasma &#946;2GPI concentrations during the acute phase response.

Sepsis remains the second largest killer in the Intensive Care Unit (ICU), giving rise to a significant economic burden ($17b per annum in the US, 0.3% of the gross domestic product). The aim of the work described in this thesis is to improve the estimation of severity in this population, with a view to improving the allocation of resources. A cohort of 2,143 adult patients with sepsis and hypotension was identified from the MIMIC-II database (v2.26). The implementation of state-of-the-art models confirms the superiority of the APACHE-IV model (AUC=73.3%) for mortality prediction using ICU admission data. Using the same subset of features, state-of-the art machine learning techniques (Support Vector Machines and Random Forests) give equivalent results. More recent mortality prediction models are also implemented and offer an improvement in discriminatory power (AUC=76.16%). A shift from expert-driven selection of variables to objective feature selection techniques using all available covariates leads to a major gain in performance (AUC=80.4%). A framework allowing simultaneous feature selection and parameter pruning is developed, using a genetic algorithm, and this offers similar performance. The model derived from the first 24 hours in the ICU is then compared with a “dynamic” model derived over the same time period, and this leads to a significant improvement in performance (AUC=82.7%). The study is then repeated using data surrounding the hypotensive episode in an attempt to capture the physiological response to hypotension and the effects of treatment. A significant increase in performance (AUC=85.3%) is obtained with the static model incorporating data both before and after the hypotensive episode. The equivalent dynamic model does not demonstrate a statistically significant improvement (AUC=85.6%). Testing on other ICU populations with sepsis is needed to validate the findings of this thesis, but the results presented in it highlight the role that data mining will increasingly play in clinical knowledge generation.

Sepsis is the leading cause of death among critically ill patients and the 10th most common cause of death overall in the United States. The mortality rates increase with severity of the disease, ranging from 15% for sepsis to 60% for septic shock. Patient with sepsis can present varied clinical symptoms depending on the personal predisposition, causal microorganism, organ system involved, and disease severity. To facilitate sepsis diagnosis, the first sepsis consensus definitions was published in 1991 and then updated in 2001. Early recognition of a sepsis patient followed with timely and appropriate treatment and management strategies have been shown to significantly reduce sepsis-related mortality, and allows care to be provided at lower costs. Despite the rapid progress in the knowledge of pathophysiological mechanisms of sepsis and its treatment in the last two decades, identifying patient with sepsis and therapeutic approaches to sepsis and its complications remains challenging to critical care clinicians. Hence, the objectives of this thesis were to 1) evaluate the test characteristics of the two sepsis consensus definitions and delineate the differences in patient profile among patients meeting or not meeting sepsis definitions; 2) determine the relationship between the changes in several physiological parameters before sepsis onset and sepsis, and to determine whether these parameters could be used to identify sepsis in critically ill adults; 3) evaluate the effect of corticosteroids therapy on patient mortality. Data used in this thesis were prospectively collected from an electronic medical record system for all the adult patients admitted into the seven critical care units (ICUs) in a tertiary medical center. Besides analyzing data at the ICU stay level, we investigated patient information in various time frames, including 24-hour, 12-hour, and 6-hour time windows. In the first study of this thesis, the 1991 sepsis definition was found to have a high sensitivity of 94.6%, but a low specificity of 61.0%. The 2001 sepsis definition had a slightly increased sensitivity but a decreased specificity, which was 96.9% and 58.3%, respectively. The areas under the ROC curve for the two consensus definitions were similar, but less than optimal. The sensitivity and area under the ROC curve of both definitions were lower at the 24-hour time window level than those of the unit stay level, though the specificity increased slightly. At the time window level, the 1991 definitions performed slightly better than the 2001 definition. In the second study, minimum systolic blood pressure performed the best, followed by maximum respiratory rate in discriminating sepsis patients from SIRS patients. Maximum heart rate and maximum respiratory rate can differentiate sepsis patients from non-SIRS patients fairly well. The area under ROC of the combination of five physiological parameters was 0.74 and 0.90 for comparing sepsis to non-infectious SIRS patients and comparing sepsis to non-SIRS patients, respectively. Parameters typically performed better in 24-hour windows compared to 6-hour or 12-hour windows. In the third study, significantly increased hospital mortality and ICU mortality were observed in the group treated with low-dose corticosteroids than the control group based on the propensity score matched comparisons, and multivariate logistic regression analyses after adjustment for propensity score alone, covariates, or propensity score (in deciles) and covariates. This thesis advances the existing knowledge by systemically evaluating the test characteristics for the 1991 and 2001 sepsis consensus definitions, delineating physiological signs and symptoms of deterioration in the preceding 24 hours prior to sepsis onset, assessing the prediction performances of single or combined physiological parameters, and examining the use of corticosteroids treatment and survival among septic shock patients. In addition, this thesis sets an innovative example on how to use data from electronic medical records as these surveillance systems are becoming increasingly popular. The results of these studies suggest that a more parsimonious set of definitional criteria for sepsis diagnosis are needed to improve sepsis case identification. In addition, continuously monitored physiological parameters could help to identify patients who show signs of deterioration prior to developing sepsis. Last but not least, caution should be used when considering a recommendation on the use of low dose corticosteroids in clinical practice guidelines for the management of sepsis.

Background Broth microdilution (BMD) is a gold-standard reference method to determine minimum inhibitory concentration (MIC) of antibiotics. For this, a standardized concentration of bacterial inoculum (2e5–8e5 colony-forming units, CFU/ml) is added to progressively higher concentrations of antibiotics. Bacteria stop growing at a particular antibiotic concentration termed MIC. Like other assays, various biological and/or technical factors can affect BMD results.   Aims To investigate the effects of inoculum concentration (5e4–5e6 CFU/ml), growth-medium concentration (cation-adjusted Mueller-Hinton Broth (CAMHB)), ranging 0.5x to 2x (1x as standard)) and age (&lt;6-months or &gt;1-year old) of fastidious medium on MIC results. And to compare BMD results using 5 different brands of CAMHBs and 1 cation-non-adjusted MH-broth (non-CAMHB).   Methods 12 isolates of bacteria (gram-positive (n=3), gram-negative(n=5), fastidious isolates (n=7)) and custom-made antibiotics-containing plates for gram-positive (11 antibiotics) or gram-negative bacteria (10 antibiotics) were used. Overnight-grown colonies were used to prepare BMD solutions (MH-broth + inoculum +/- fastidious) which were plated on antibiotic-plates as well as diluted prior to plating on agar-plates. Antibiotic- and agar-plates were incubated (18–20hr, 35°C) and used to determine MICs (following European Committee on Antimicrobial Susceptibility Testing instructions) and actual number of viable bacteria in BMD solutions, respectively.   Results Increasing inoculum concentration increased MICs of all antibiotics except cefoxitin. Piperacillin–tazobactam, levofloxacin, benzylpenicillin and ampicillin were especially sensitive to increase in inoculum and showed a 4-fold increase in &gt;50% isolates. MICs for tobramycin, tigecycline and gentamicin increased by 2-fold in &gt;50% isolates every time MH-broth concentration increased. Age of fastidious medium had no decipherable pattern of effects on MIC. All MH-broths gave similar results except when testing daptomycin which gave higher MICs with non-CAMHB compared to CAMHB.    Conclusion This research reveals some technical factors affecting MIC results. These results could help define parameters for automated BMD-performing-systems. However, this research shows only trends as more replicates are needed to determine statistically significant results.