There are multiple immune mechanisms identified for persistence of hepatitis B virus (HBV) infection. This thesis considers the vital role that inhibitory receptors play in contributing to impairment of the adaptive immune system in chronic hepatitis B (CHB), and the potential role they play in the innate immune system, focusing on the inhibitory receptor leucocyte-associated immunoglobulin-like receptor (LAIR)-1. The unique aspect of this work is that for the first time LAIR-1 expression has been investigated on natural killer (NK) cells in CHB. Our striking findings of increased LAIR-1 expression on peripheral NK cells in CHB and an inverse correlation between expression and effector function suggest this inhibitory receptor could have a potential role in exhaustion of NK cells in CHB. We therefore additionally explored the expression of LAIR-1 on circulating NK cells from patients with hepatocellular carcinoma (HCC) and non-alcoholic fatty liver disease (NAFLD). The particular relevance of LAIR-1 to liver disease is that one of its major ligands is collagen. We demonstrated a downregulation of LAIR-1 expression on intrahepatic NK cells, which we postulate might occur following repetitive engagement with abundant collagen within the liver. In line with this, intrahepatic NK cells with a liver-resident (CXCR6+) phenotype had even lower LAIR-1 expression than liver infiltrating (non-resident, CXCR6-) NK cells. Furthermore, preliminary experiments display attenuation of the cytotoxic degranulation capacity (CD107a) by circulating NK cells from CHB patients upon exposure to plate-bound collagen. We demonstrate differential expression of LAIR-1 on NK cells in viral hepatitis, HCC and NAFLD and between peripheral and intrahepatic NK cells. Preliminary experiments demonstrate a role in inhibiting NK cell function suggesting this as a novel therapeutic target to harness the capacity of NK cells to control chronic infection and cancer.

INTRODUÇÃO: A utilização da ultra-sonografia (USG) como método de diagnóstico por imagem na avaliação das afecções abdominais, em particular para o acompanhamento de pacientes portadores de hepatite C crônica, vem sendo rotineiramente empregada. Neste trabalho, avaliamos a contribuição da USG na avaliação das alterações histopatológicas encontradas neste grupo de doentes, com ênfase para a esteatose hepática (EH), afecção bastante freqüente na hepatite causada pelo vírus C. MÉTODO: Comparamos os achados ultra-sonográficos de 192 pacientes consecutivos, portadores de hepatite crônica pelo vírus C, submetidos à biópsia hepática, com os achados histopatológicos dos fragmentos hepáticos obtidos. Todos os pacientes foram biopsiados sob orientação USG, sendo a ultra-sonografia assim como a biópsia hepática realizadas cada qual por um médico especialista e sempre o mesmo. Todos os exames ultra-sonográficos obedeceram a um mesmo protocolo, sendo analisados os seguintes parâmetros ultra-sonográficos: 1) com relação às características ecográficas do parênquima: ecogenicidade, ecotextura e atenuação; 2) com relação à utilização da USG para o diagnóstico da EH: biometria da parede abdominal, dimensões e contornos hepáticos. Posteriormente os pacientes estudados foram agrupados em: A) grupo com alterações ultra-sonográficas e B) sem alterações ultra-sonográficas, e comparados com as alterações histopatológicas presentes. Foram realizados também cálculos de regressão logística com os parâmetros USG avaliados para a avaliação da acurácia deste método de imagem para o diagnóstico da EH. RESULTADOS: Entre as alterações histopatológicas presentes, a alteração arquitetural e a EH apresentaram diferença estatística significante entre os grupos A (com alterações USG) e B (sem alterações USG). Observou-se também diferença estatística significante entre: a) espessura da parede abdominal e as dimensões hepáticas com relação à presença de EH, b) contornos hepáticos irregulares e a presença de EH. E dentre os componentes ultra-sonográficos avaliados, a atenuação foi o que apresentou melhor correlação com a EH. A utilização das variáveis idade, sexo, atenuação, espessura da parede abdominal e dimensões hepáticas, foram as que apresentaram melhores resultados nos cálculos de regressão logística, com sensibilidade de 60,5% e especificidade de 83,9% em diagnosticar EH. CONCLUSÕES: Neste trabalho, o estudo ultra-sonográfico do fígado de pacientes com hepatite C crônica apresentou correlação com as alterações arquiteturais e com a EH encontradas na histopatologia. A utilização da USG para o diagnóstico da EH apresentou relação estatística com a espessura da parede abdominal, dimensões e contornos hepáticos, e a atenuação foi o melhor componente ultra-sonográfico para o diagnóstico da EH. / INTRODUCTION: Ultrasonography is consistently utilized as the method of diagnostic imaging while evaluating abdominal infections particularly in patients with chronic hepatitis C. We studied the contribution of the ultrasonography in the evaluation of histopathologic alterations in this group of patients with emphasis in hepatic steatosis (HS), sufficiently frequent in hepatitis caused by the C virus. METHODS: We compared the findings from the ultrasounds of 192 carrying patients of chronic hepatitis C virus, who had undergone hepatic biopsy, with the histopathogical findings of the hepatic fragments obtained. All patients who have undergone liver biopsy guided by ultrasonography were always evaluated by the same medical specialist for both sonogram or hepatic biopsy. All ultrasound examinations followed the same protocol, analyzing the following parameters: 1) regarding to the echographic characteristics of parenchyma: echogenicity, echotexture and attenuation; 2) regarding to the use of the sonography for the diagnosis of the HS: biometry of the abdominal wall, hepatic dimensions and contours. Post results, patients had been grouped in: A) altered ultrasound group and B) ultrasound group without ultrasound alterations, both compared with present histopathological alterations. Calculations of logistic regression with ultrasonography parameters had also been performed to determine the accuracy of this method for the HS diagnosis. RESULTS: Of the histopathological alterations present, the architectural alteration and the HS had presented significant statistical difference between the groups (altered ultrasound group) and the B (without ultrasound alterations). We also noted significant statistical difference between: a) thickness of the abdominal wall and the hepatic dimensions with regard to presence of HS, b) irregular hepatic contours and the presence of HS. Amongst the evaluated ultrasound components, attenuation presented better correlation with the HS. The variables age, sex, attenuation, thickness of the abdominal wall and hepatic dimensions of the right lobe, presented better results in the calculations of logistic regression, with 60,5% sensitivity and specificity of 83,9% in diagnosing HS. CONCLUSIONS: In this research, the hepatic ultrasonography of patients with chronic hepatitis C presented correlation with the architectural alterations and the HS found at the histopathology. The utilization of the ultrasonography for the diagnosis of the HS presented statistical relationship with the thickness of the abdominal wall, hepatic dimensions and contours, and the sonographic attenuation was the best component for the diagnosis of ES.

INTRODUÇÃO: A Doença Hepática Gordurosa (DHG) é considerada um dos grandes problemas de saúde pública do novo milênio, impulsionada sobretudo pela epidemia de obesidade. Está relacionada com alta morbidade, piora da qualidade de vida e custos econômicos para a sociedade. Existem duas formas histopatológicas iniciais inseridas dentro da DHG: a esteatose e a esteato-hepatite que podem evoluir para cirrose e hepatocarcinoma. A maior parte da literatura sobre epidemiologia da doença hepática gordurosa utiliza desenhos retrospectivos e meios diagnósticos não invasivos, embora o padrão ouro seja a biópsia hepática. Medidas preventivas e de controle adequados deverão ser tomadas baseadas em informações epidemiológicas envolvendo população \"sadia\". A excelente correspondência das alterações histopatológicas encontradas no cadáver em relação ao vivo permite extrapolar dados da frequência de esteatose e esteato-hepatite encontradas em uma população jovem vítima de morte violenta para uma população \"normal\". Contudo, não há estudo prévio que avalie frequência e fatores preditivos de esteatose e esteatohepatite em fígados de cadáver. O objetivo deste estudo foi avaliar a esteatose e a esteato-hepatite em fígados de adultos vítimas de morte violenta. MÉTODOS: As amostras foram coletadas de 224 adultos submetidos a autópsia forense a partir de setembro de 2011 a abril de 2013. Dados antropométricos e do fígado foram registrados. O exame histopatológico foi realizado em seis amostras obtidas com base em diferentes lóbulos de cada fígado. Cada amostra foi tratada com quatro corantes: hematoxilina-eosina, Perls, pricosirius e tricrômio de Masson. Desfechos de interesse foram a presença de esteatose, esteato-hepatite, fibrose e siderose. RESULTADOS: A amostra apresentou uma média de idade de 40 anos. A esteatose foi diagnosticada em 48,2% dos casos e esteato-hepatite em 2,7%. Uma alta prevalência de fígado gorduroso foi verificada entre homens e indivíduos mais velhos, sendo a faixa etária mais atingida entre 41-60 anos. Os fatores significativamente associados com o aumento do risco de esteatose foram circunferência abdominal (p < 0,001), IMC(p < 0,001), peso do fígado (p=0,002), assim como a presença de siderose (p=0.018). CONCLUSÃO: A alta prevalência de esteatose hepática foi detectada em biópsias pós-morte de uma população jovem. Uma vez que esta doença pode ter consequências clínicas severas, esse dado é importante para avaliar medidas preventivas para a doença hepática gordurosa e suas graves consequências / BACKGROUND: Fatty liver disease (FLD) is considered one of the major public health problems of the new millennium, driven mainly by the obesity epidemic. It is related to high morbidity, worsening of quality of life and economic costs to society. There are two initial histopathological forms inserted into the FLD: steatosis and steatohepatitis which can progress to cirrhosis and hepatocellular carcinoma. Most of the literature on epidemiology of FLD using retrospective drawings and non invasive means, but the gold standard is a liver biopsy. Preventive measures and adequate control should be taken based on epidemiological information involving population \"healthy\". The excellent correlation of histopathologic changes found in the body in live relationship allows extrapolating data from steatosis to steatohepatitis and often found in a population young victim of violent death to a \"normal\" population. However, no previous study to assess the frequency and predictors of steatosis and steatohepatitis in cadaver livers. The aim of this study is to evaluate steatosis and steatohepatitis in livers of adult victims of violent death. METHODS: Specimens were collected from 224 adults undergoing forensic autopsy from September 2011 to April 2013. Anthropometric and liver data were recorded. Histopathological examination was performed on six biopsies obtained from different lobes of each liver. Each sample was treated with 4 stains: hematoxylin-eosin, Perls, pricosirius and trichrome Masson. Outcomes of interest were the presence of steatosis, steatohepatitis, fibrosis and siderosis. RESULTS: The sample had an average age of 40 years. The steatosis was detected in 48.2% of cases and 2.7% steatohepatitis. A high prevalence of fatty liver was observed among men and older individuals, the age group most affected between 41-60 years. The factors significantly associated with increased risk of steatosis were waist circumference (p < 0.001), BMI (p < 0.001), liver weight (p = 0.002) as well as the presence of siderosis ( p = 0.018). CONCLUSION: The high prevalence of hepatic steatosis was detected in postmortem biopsy of a young population. Since this disease can have severe clinical consequences, this data is important to evaluate preventive measures for fatty liver disease and its serious consequences

A colelitíase é uma doença frequente na população geral. Um dos seus fatores de risco é a diabetes melitus tipo 2, relacionada à anormalidades metabólicas associadas a sobrepeso, obesidade, resistência à insulina, hipertrigliceridemia e hábitos dietéticos. Fatores de risco semelhantes são encontrados na doença hepática gordurosa não alcoólica (DHGNA). A DHGNA engloba um espectro de condições patológicas que pode evoluir da esteatose, para esteato-hepatite (EHNA), fibrose, cirrose e neoplasia hepática. A distinção entre esteatose e EHNA é de grande relevância na prática clínica, em virtude de a primeira ser uma condição benigna e reversível, enquanto que a segunda apresenta potencial evolutivo para cirrose e carcinoma hepatocelular. Somente a biópsia hepática pode classificar e estadiar a DHGNA. A DHGNA e a colelitíase têm similaridade quanto à patogênese e aos fatores de risco, o que nos motivou a realizar este estudo. Os objetivos do trabalho foram: a) Definir a frequência da esteatose hepática e da EHNA em pacientes com colelitíase submetidos à colecistectomia laparoscópica. b) Avaliar as alterações histopatológicas da DHGNA nos pacientes com colelitíase. c) Avaliar a acurácia dos exames de imagem-ultrassonografia abdominal (US) e tomografia computadorizada (TC) no diagnóstico da DHGNA. d) Relacionar aspectos clínicos, laboratoriais e de imagem com diagnósticos histopatológicos de esteatose e EHNA em portadores de colelitíase. e) Analisar variáveis preditivas da DHGNA na indicação da biópsia hepática para os pacientes com colelitíase a serem submetidos à colecistectomia laparoscópica. Método: Foi realizado estudo prospectivo sequencial de pacientes portadores de colelitíase com indicação cirúrgica que assinaram o termo de consentimento livre e esclarecido. Foram analisados 161 pacientes submetidos à colecistectomia laparoscópica e à biópsia hepática. Os pacientes foram avaliados quanto ao sexo, à idade, história clínica e aos antecedentes pessoais, com ênfase nas comorbidades relacionadas à síndrome metabólica. Foram realizadas as seguintes medidas antropométricas: peso (kg), altura (m) e circunferência abdominal (cm), sendo calculado o Índice de Massa Corpórea (IMC). Além da avaliação bioquímica, foram avaliados parâmetros metabólicos através da dosagem da glicemia e insulinemia de jejum, índice de HOMA IR e perfil lipídico. Os pacientes foram submetidos a dois USs em momentos distintos, nos quais foram avaliados a vesícula biliar, as vias biliares e os possíveis diagnósticos qualitativo e quantitativo da esteatose hepática. Na tomografia abdominal, foram medidos os coeficientes de atenuação hepática e esplênica. O diagnóstico de esteatose foi determinado através de dois índices: TC1 (e-h) calculado pela diferença entre o valor da atenuação esplênica e hepática e o TC2 (h/e) medido pela fração da atenuação hepática sobre a esplênica. Antes da colecistectomia laparoscópica com exploração de vias biliares, foi realizada biópsia hepática com agulha de tru-cut no mesmo tempo cirúrgico. Os parâmetros histopatológicos utilizados para avaliar as biópsias hepáticas foram: esteatose macrovesicular, esteatose microvesicular, infiltrado inflamatório acinar e portal, balonização hepatocelular, corpúsculos hialino de Mallory, alterações ductulares e fibrose perissinusoidal, perivenular, portal, sobrecarga de ferro e pseudoinclusão nuclear de glicogênio. Para o diagnóstico de EHNA, foi utilizado o escore de atividade da doença hepática gordurosa não alcoólica (NAS). Os 161 pacientes foram distribuídos em três grupos formados a partir do resultado da histopatologia hepática: Grupo A - colelitíase sem esteatose (n = 98), Grupo B - colelitíase com esteatose (n = 51) e Grupo C - colelitíase com esteatohepatite (n = 12). Resultados: Entre os 161 pacientes submetidos à colecistectomia com biópsia hepática, 63 (39,1%) eram portadores de DHGNA, dentre eles, 12/161 (7,4%) com EHNA. Cento e trinta e sete (85%) pacientes eram do sexo feminino; 125 (78%) eram brancos. A idade média global foi de 45 anos. A hipertensão arterial sistêmica esteve presente em 40 (25%), diabetes mellitus tipo 2 em 17 (11%) e a síndrome metabólica em 39 (24%). Os aspectos clínicos, laboratoriais e comorbidades que apresentaram diferença estatística significantes entre o grupo A e os grupos B e C foram: idade, IMC, circunferência abdominal, glicemia em jejum, ALT. A síndrome metabólica, a resistência insulínica, diabetes mellitus tipo 2, AST e o colesterol total registraram diferença estatisticamente significante apenas entre os grupos A e C. Não existiram aspectos clínicos, laboratoriais ou de comorbidades que diferenciaram os portadores de esteatose e EHNA. Os exames de US I e II nas duas ocasiões revelaram sensibilidade de 57% e 59%, especificidade de 91% e 90%, respectivamente, e em ambos USs a acurácia foi de 78%. No exame de TC, o índice e o nível de corte de maior sensibilidade (50%), especificidade, (90,72%) e acurácia (74,53%) foi o índice TC 2 (h/e), com nível de corte menor que 1,0 para o diagnóstico da DHGNA. Os parâmetros histopatológicos que apresentaram diferença estatística significante entre os grupos A e C e entre os grupos B e C foram: corpúsculos hialino de Mallory, infiltrado inflamatório portal e fibrose perivenular, perissinusoidal e portal. Houve maior grau de intensidade do infiltrado inflamatório portal nos pacientes do grupo C. Houve diferença estatística significante entre os grupos B e C com relação à esteatose microvesicular e a pseudoinclusão nuclear de glicogênio. Pela regressão logística, foi avaliada a probabilidade de os pacientes portadores de colelitíase apresentarem DHGNA. Os fatores preditivos foram: aumento da glicemia, HOMA-IR, colesterol total, circunferência abdominal e esteatose ao US. Na presença de três ou quatro destes fatores de risco a probabilidade de DHGNA foi de 91%. Conclusão: A prevalência de EHNA em pacientes com colelitíase foi de 7,4% neste grupo de pacientes Assim, é de fundamental importância o reconhecimento dos fatores de risco para a DHGNA em pacientes com colelitíase que serão submetidos à intervenção cirúrgica. Assim sendo, a biópsia hepática durante o procedimento cirúrgico deve ser preconizada na vigência de fatores preditivos, pois é o único método para diferenciar esteatose de EHNA / Cholelithiasis is a very common disease in the population at large, and one of the risk factors is type II diabetes mellitus, which is related to metabolic disorders associated with overweight, obesity, insulin resistance, hypertriglyceridemia and dietary abnormalities. Similar risk factors are found in non-alcoholic fatty liver disease (NAFLD). NAFLD covers a spectrum of pathological conditions that can range from steatosis to steatohepatitis (NASH), fibrosis, cirrhosis and even liver cancer. The distinction between steatosis and NASH is of great importance in clinical practice because the former is a benign, reversible condition whereas the latter can progress to cirrhosis and hepatocellular carcinoma. Only a liver biopsy, however, can be used to classify and stage NAFLD. NAFLD and cholelithiasis have similar pathogenesis and risk factors, a fact which led us to undertake this study, the aims of which were: a) to define the frequency of hepatic steatosis and NASH in patients with cholelithiasis undergoing laparoscopic cholecystectomy; b) to assess the accuracy of abdominal ultrasound imaging (US) and computed tomography (CT) in the diagnosis of NAFLD; c) to assess histological alterations caused by NAFLD in patients with cholelithiasis; d) to relate clinical, laboratory and imaging findings to histopathological diagnoses of steatosis and NASH in cholelithiasis; and e) to analyze predictors of NAFLD used when referring patients with cholelithiasis already scheduled for laparoscopic cholecystectomy for liver biopsy as well. Methods: We performed a prospective sequential study of patients with cholelithiasis who had been referred for surgery and had signed a voluntary informed-consent form. A total of 161 patients were analyzed after they had undergone a laparoscopic cholecystectomy and liver biopsy. Besides sex and age, clinical and medical history were recorded, with emphasis being placed on comorbidities related to metabolic syndrome. The anthropometric measurements weight (kg), height (m) and abdominal circumference (cm) were recorded during the physical examination and the body mass index was calculated. Biochemical and metabolic assessment parameters, including fasting blood sugar and fasting insulin, which were used to calculate the HOMA-IR index, and fasting lipid profile, were evaluated. Patients had two ultrasounds at different times to assess the gallbladder and bile ducts as well as the quantitative and qualitative diagnosis of hepatic steatosis. In the abdominal tomography, the attenuation coefficients of the liver and spleen were measured for diagnosis of steatosis based on two indices: CT1 (S-L), given by the difference between spleen and liver attenuations, and CT2 (L/S), given by the attenuation of the liver divided by the attenuation of the spleen. Before laparoscopic cholecystectomy with bile duct exploration, a liver biopsy with a tru-cut was performed. The following histological parameters were used to evaluate the liver biopsies: macrovesicular steatosis, microvesicular steatosis, acinar and portal inflammatory infiltrate, hepatocellular ballooning, Mallory bodies, ductal changes, perisinusoidal, perivenular and portal fibrosis, iron overload and glycogenated nuclei. The NAFLD activity score was used to diagnose NAFLD in the steatosis or NASH phases. A comparative analysis of the 161 patients was carried out after they had been divided into three groups according to the results of the liver histopathology: group A cholelithiasis without steatosis (n=98), group B - cholelithiasis with steatosis (n=51) and group C - cholelithiasis with NASH (n=12). Results: Of the 161 patients subjected to cholecystectomy with a liver biopsy, 63 (39.1%) had NAFLD, of whom 12 (7.4%) also had NASH. A total of 137 (85%) of the patients were female, and 125 (78%) were Caucasian. Average age was 45 years. Arterial hypertension was observed in 40 (25%) patients, 17 (11%) had diabetes mellitus and 39 (24%) had metabolic syndrome. The clinical and laboratory findings with a statistically significant difference between group A and/or groups B and C were age, BMI, abdominal circumference, fasting blood sugar, total cholesterol, ALT and AST. Metabolic syndrome, insulin resistance and diabetes mellitus only exhibited a statistically significant difference between groups A and C. There were no clinical or laboratory findings or image abnormalities that differentiated steatosis from NASH. The first and second ultrasounds, which were carried out at different times, had sensitivities of 57% and 59% and specificities of 91% and 90%, respectively; both had accuracies of 78%. In the computed tomography, the index with the greatest sensitivity (50%), specificity (90.72%) and accuracy (74.53%) was CT2 (L/S), with a cutoff level of 1.0 for diagnosis of NAFLD. The histopathological parameters with statistically significant differences between the group without steatosis and group C and between groups B and C were Mallory bodies, portal inflammation and perivenular, perisinusoidal and portal fibrosis. Portal inflammation was more intense in patients in group C. There was a statistically significant difference in the intensity of macrovesicular steatosis between groups B and C; this was mild in 42 (82.4%) of the patients in the former group and in only 2 (3.9%) in the latter. There was a statistically significant difference in microvesicular steatosis and glycogenated nuclei between groups B and C. Logistic regression revealed that the associated risk factors for determining the probability of patients with cholelithiasis having NAFLD are increased values of blood glucose, HOMA-IR, total cholesterol abdominal circumference and steatosis on ultrasound. In the presence of three or four risk factors the probability of NAFLD was 91%. Conclusion: The prevalence of NASH in cholelithiasis patients was 7.4%, indicating that NAFLD is a serious problem in this group of patients. It is therefore very important to determine the risk factors for NAFLD in cholelithiasis patients who will be submitted to surgery in order to decide whether a liver biopsy should be performed, as this is the only diagnostic method for differentiating between steatosis and NASH

A colelitíase é uma doença frequente na população geral. Um dos seus fatores de risco é a diabetes melitus tipo 2, relacionada à anormalidades metabólicas associadas a sobrepeso, obesidade, resistência à insulina, hipertrigliceridemia e hábitos dietéticos. Fatores de risco semelhantes são encontrados na doença hepática gordurosa não alcoólica (DHGNA). A DHGNA engloba um espectro de condições patológicas que pode evoluir da esteatose, para esteato-hepatite (EHNA), fibrose, cirrose e neoplasia hepática. A distinção entre esteatose e EHNA é de grande relevância na prática clínica, em virtude de a primeira ser uma condição benigna e reversível, enquanto que a segunda apresenta potencial evolutivo para cirrose e carcinoma hepatocelular. Somente a biópsia hepática pode classificar e estadiar a DHGNA. A DHGNA e a colelitíase têm similaridade quanto à patogênese e aos fatores de risco, o que nos motivou a realizar este estudo. Os objetivos do trabalho foram: a) Definir a frequência da esteatose hepática e da EHNA em pacientes com colelitíase submetidos à colecistectomia laparoscópica. b) Avaliar as alterações histopatológicas da DHGNA nos pacientes com colelitíase. c) Avaliar a acurácia dos exames de imagem-ultrassonografia abdominal (US) e tomografia computadorizada (TC) no diagnóstico da DHGNA. d) Relacionar aspectos clínicos, laboratoriais e de imagem com diagnósticos histopatológicos de esteatose e EHNA em portadores de colelitíase. e) Analisar variáveis preditivas da DHGNA na indicação da biópsia hepática para os pacientes com colelitíase a serem submetidos à colecistectomia laparoscópica. Método: Foi realizado estudo prospectivo sequencial de pacientes portadores de colelitíase com indicação cirúrgica que assinaram o termo de consentimento livre e esclarecido. Foram analisados 161 pacientes submetidos à colecistectomia laparoscópica e à biópsia hepática. Os pacientes foram avaliados quanto ao sexo, à idade, história clínica e aos antecedentes pessoais, com ênfase nas comorbidades relacionadas à síndrome metabólica. Foram realizadas as seguintes medidas antropométricas: peso (kg), altura (m) e circunferência abdominal (cm), sendo calculado o Índice de Massa Corpórea (IMC). Além da avaliação bioquímica, foram avaliados parâmetros metabólicos através da dosagem da glicemia e insulinemia de jejum, índice de HOMA IR e perfil lipídico. Os pacientes foram submetidos a dois USs em momentos distintos, nos quais foram avaliados a vesícula biliar, as vias biliares e os possíveis diagnósticos qualitativo e quantitativo da esteatose hepática. Na tomografia abdominal, foram medidos os coeficientes de atenuação hepática e esplênica. O diagnóstico de esteatose foi determinado através de dois índices: TC1 (e-h) calculado pela diferença entre o valor da atenuação esplênica e hepática e o TC2 (h/e) medido pela fração da atenuação hepática sobre a esplênica. Antes da colecistectomia laparoscópica com exploração de vias biliares, foi realizada biópsia hepática com agulha de tru-cut no mesmo tempo cirúrgico. Os parâmetros histopatológicos utilizados para avaliar as biópsias hepáticas foram: esteatose macrovesicular, esteatose microvesicular, infiltrado inflamatório acinar e portal, balonização hepatocelular, corpúsculos hialino de Mallory, alterações ductulares e fibrose perissinusoidal, perivenular, portal, sobrecarga de ferro e pseudoinclusão nuclear de glicogênio. Para o diagnóstico de EHNA, foi utilizado o escore de atividade da doença hepática gordurosa não alcoólica (NAS). Os 161 pacientes foram distribuídos em três grupos formados a partir do resultado da histopatologia hepática: Grupo A - colelitíase sem esteatose (n = 98), Grupo B - colelitíase com esteatose (n = 51) e Grupo C - colelitíase com esteatohepatite (n = 12). Resultados: Entre os 161 pacientes submetidos à colecistectomia com biópsia hepática, 63 (39,1%) eram portadores de DHGNA, dentre eles, 12/161 (7,4%) com EHNA. Cento e trinta e sete (85%) pacientes eram do sexo feminino; 125 (78%) eram brancos. A idade média global foi de 45 anos. A hipertensão arterial sistêmica esteve presente em 40 (25%), diabetes mellitus tipo 2 em 17 (11%) e a síndrome metabólica em 39 (24%). Os aspectos clínicos, laboratoriais e comorbidades que apresentaram diferença estatística significantes entre o grupo A e os grupos B e C foram: idade, IMC, circunferência abdominal, glicemia em jejum, ALT. A síndrome metabólica, a resistência insulínica, diabetes mellitus tipo 2, AST e o colesterol total registraram diferença estatisticamente significante apenas entre os grupos A e C. Não existiram aspectos clínicos, laboratoriais ou de comorbidades que diferenciaram os portadores de esteatose e EHNA. Os exames de US I e II nas duas ocasiões revelaram sensibilidade de 57% e 59%, especificidade de 91% e 90%, respectivamente, e em ambos USs a acurácia foi de 78%. No exame de TC, o índice e o nível de corte de maior sensibilidade (50%), especificidade, (90,72%) e acurácia (74,53%) foi o índice TC 2 (h/e), com nível de corte menor que 1,0 para o diagnóstico da DHGNA. Os parâmetros histopatológicos que apresentaram diferença estatística significante entre os grupos A e C e entre os grupos B e C foram: corpúsculos hialino de Mallory, infiltrado inflamatório portal e fibrose perivenular, perissinusoidal e portal. Houve maior grau de intensidade do infiltrado inflamatório portal nos pacientes do grupo C. Houve diferença estatística significante entre os grupos B e C com relação à esteatose microvesicular e a pseudoinclusão nuclear de glicogênio. Pela regressão logística, foi avaliada a probabilidade de os pacientes portadores de colelitíase apresentarem DHGNA. Os fatores preditivos foram: aumento da glicemia, HOMA-IR, colesterol total, circunferência abdominal e esteatose ao US. Na presença de três ou quatro destes fatores de risco a probabilidade de DHGNA foi de 91%. Conclusão: A prevalência de EHNA em pacientes com colelitíase foi de 7,4% neste grupo de pacientes Assim, é de fundamental importância o reconhecimento dos fatores de risco para a DHGNA em pacientes com colelitíase que serão submetidos à intervenção cirúrgica. Assim sendo, a biópsia hepática durante o procedimento cirúrgico deve ser preconizada na vigência de fatores preditivos, pois é o único método para diferenciar esteatose de EHNA / Cholelithiasis is a very common disease in the population at large, and one of the risk factors is type II diabetes mellitus, which is related to metabolic disorders associated with overweight, obesity, insulin resistance, hypertriglyceridemia and dietary abnormalities. Similar risk factors are found in non-alcoholic fatty liver disease (NAFLD). NAFLD covers a spectrum of pathological conditions that can range from steatosis to steatohepatitis (NASH), fibrosis, cirrhosis and even liver cancer. The distinction between steatosis and NASH is of great importance in clinical practice because the former is a benign, reversible condition whereas the latter can progress to cirrhosis and hepatocellular carcinoma. Only a liver biopsy, however, can be used to classify and stage NAFLD. NAFLD and cholelithiasis have similar pathogenesis and risk factors, a fact which led us to undertake this study, the aims of which were: a) to define the frequency of hepatic steatosis and NASH in patients with cholelithiasis undergoing laparoscopic cholecystectomy; b) to assess the accuracy of abdominal ultrasound imaging (US) and computed tomography (CT) in the diagnosis of NAFLD; c) to assess histological alterations caused by NAFLD in patients with cholelithiasis; d) to relate clinical, laboratory and imaging findings to histopathological diagnoses of steatosis and NASH in cholelithiasis; and e) to analyze predictors of NAFLD used when referring patients with cholelithiasis already scheduled for laparoscopic cholecystectomy for liver biopsy as well. Methods: We performed a prospective sequential study of patients with cholelithiasis who had been referred for surgery and had signed a voluntary informed-consent form. A total of 161 patients were analyzed after they had undergone a laparoscopic cholecystectomy and liver biopsy. Besides sex and age, clinical and medical history were recorded, with emphasis being placed on comorbidities related to metabolic syndrome. The anthropometric measurements weight (kg), height (m) and abdominal circumference (cm) were recorded during the physical examination and the body mass index was calculated. Biochemical and metabolic assessment parameters, including fasting blood sugar and fasting insulin, which were used to calculate the HOMA-IR index, and fasting lipid profile, were evaluated. Patients had two ultrasounds at different times to assess the gallbladder and bile ducts as well as the quantitative and qualitative diagnosis of hepatic steatosis. In the abdominal tomography, the attenuation coefficients of the liver and spleen were measured for diagnosis of steatosis based on two indices: CT1 (S-L), given by the difference between spleen and liver attenuations, and CT2 (L/S), given by the attenuation of the liver divided by the attenuation of the spleen. Before laparoscopic cholecystectomy with bile duct exploration, a liver biopsy with a tru-cut was performed. The following histological parameters were used to evaluate the liver biopsies: macrovesicular steatosis, microvesicular steatosis, acinar and portal inflammatory infiltrate, hepatocellular ballooning, Mallory bodies, ductal changes, perisinusoidal, perivenular and portal fibrosis, iron overload and glycogenated nuclei. The NAFLD activity score was used to diagnose NAFLD in the steatosis or NASH phases. A comparative analysis of the 161 patients was carried out after they had been divided into three groups according to the results of the liver histopathology: group A cholelithiasis without steatosis (n=98), group B - cholelithiasis with steatosis (n=51) and group C - cholelithiasis with NASH (n=12). Results: Of the 161 patients subjected to cholecystectomy with a liver biopsy, 63 (39.1%) had NAFLD, of whom 12 (7.4%) also had NASH. A total of 137 (85%) of the patients were female, and 125 (78%) were Caucasian. Average age was 45 years. Arterial hypertension was observed in 40 (25%) patients, 17 (11%) had diabetes mellitus and 39 (24%) had metabolic syndrome. The clinical and laboratory findings with a statistically significant difference between group A and/or groups B and C were age, BMI, abdominal circumference, fasting blood sugar, total cholesterol, ALT and AST. Metabolic syndrome, insulin resistance and diabetes mellitus only exhibited a statistically significant difference between groups A and C. There were no clinical or laboratory findings or image abnormalities that differentiated steatosis from NASH. The first and second ultrasounds, which were carried out at different times, had sensitivities of 57% and 59% and specificities of 91% and 90%, respectively; both had accuracies of 78%. In the computed tomography, the index with the greatest sensitivity (50%), specificity (90.72%) and accuracy (74.53%) was CT2 (L/S), with a cutoff level of 1.0 for diagnosis of NAFLD. The histopathological parameters with statistically significant differences between the group without steatosis and group C and between groups B and C were Mallory bodies, portal inflammation and perivenular, perisinusoidal and portal fibrosis. Portal inflammation was more intense in patients in group C. There was a statistically significant difference in the intensity of macrovesicular steatosis between groups B and C; this was mild in 42 (82.4%) of the patients in the former group and in only 2 (3.9%) in the latter. There was a statistically significant difference in microvesicular steatosis and glycogenated nuclei between groups B and C. Logistic regression revealed that the associated risk factors for determining the probability of patients with cholelithiasis having NAFLD are increased values of blood glucose, HOMA-IR, total cholesterol abdominal circumference and steatosis on ultrasound. In the presence of three or four risk factors the probability of NAFLD was 91%. Conclusion: The prevalence of NASH in cholelithiasis patients was 7.4%, indicating that NAFLD is a serious problem in this group of patients. It is therefore very important to determine the risk factors for NAFLD in cholelithiasis patients who will be submitted to surgery in order to decide whether a liver biopsy should be performed, as this is the only diagnostic method for differentiating between steatosis and NASH

Abstract available through The FASEB Journal.

Abstract not available

Abstract Metabolic Syndrome (MetSyn) is a medical condition prevalent in Australia. MetSyn is diagnosed with a varying combination of visceral obesity, insulin resistance/ impaired glucose tolerance/ Type 2 diabetes, dyslipidaemia and hypertension. Obesity is a central feature of this syndrome that is characterised by abnormalities in glucose and lipid metabolism. An understanding of the cause of the metabolic derangement that occurs in obesity, and that contributes to MetSyn, would allow effective treatment and prevention strategies to be formulated. This is a priority in the current environment of highly prevalent overweight and obesity in Australian children and adults. Lipotoxicity of insulin-dependent tissues and ectopic fat depots are emerging as fundamental processes in the pathogenesis of MetSyn. Lifestyle intervention, such as increased physical activity, show great promise as agents for disrupting the disease progression and may act via direct or indirect mechanisms on the underlying pathology of MetSyn. This study aimed to determine if diagnostic markers of MetSyn exist in obese, prepubertal, Australian children and to assess the contribution of lifestyle factors on components of MetSyn. Further, this study sought to investigate the relationship between body fat patterning (total body fat, abdominal adipose depots, skeletal intramyocellular lipids, intrahepatocellular lipids) and markers of MetSyn. An experimental intervention was then employed to examine the effect of physical activity on body fat distribution, insulin sensitivity, and haemodynamic and biochemical markers of MetSyn, and additionally to determine if the effect of exercise on parameters of MetSyn was mediated by a change in body fat patterning. Data were collected in a group of 15 obese (mean BMI Z-score 2.51 ± 0.49), prepubertal children (6 male, 9 female) aged 5.1 – 11.4 years (mean age 7.82 yrs ± 1.83). Measures included insulin sensitivity, blood biochemistry (lipid, haemostatic and adipocyte activity markers), blood pressure, two-compartment body composition by hydrometry, and nuclear magnetic resonance scanning for abdominal adipose depots, intrahepatic lipids and skeletal intramyocellular lipids. Each child’s habitual nutrition and physical activity were also ascertained using multiple-pass 24-hr diet recalls and accelerometry respectively. Data collection was conducted pre and post a 12-week physical activity intervention which consisted of cardiorespiratory activity during instructor led sessions (60 mins, twice weekly) and family led sessions (>10 mins, 4 days/wk). There is no universally accepted definition of MetSyn in childhood. The International Diabetes Federation suggests that MetSyn should not be diagnosed in children aged 6 to < 10 years. Children can be identified to be at risk of MetSyn, however, based on waist circumference ≥90th percentile and family history1,2; all subjects in this study were at risk according to these criteria. Four definitions of paediatric MetSyn previously applied to a group of young, overweight Australian children3 were used to calculate the prevalence of MetSyn in the current sample and it was found to be 27-89% at baseline and 13-80% after the experimental intervention depending upon the definition used. Acanthosis nigricans and impaired glucose tolerance (IGT) were present in one female child. Post-intervention, IGT had resolved and the child was glucose tolerant. Habitual dietary intake (energy intake and macronutrients) measured over a 3-day period pre-intervention displayed a significant positive association between fasting glucose and energy intake, as well as a significant negative association between fasting glucose and the protein component of the diet. Following the physical activity programme, energy intake was significantly positively correlated with body fat percentage (% BF). There was no difference found in dietary intake assessed prior to and following cessation of the physical activity intervention, in terms of energy or % energy from macronutrients. Habitual physical activity was not related to MetSyn diagnostic indicators. A higher level of physical fitness, estimated by predicted O2max (ml•kg-1•min-1), was significantly correlated with a lower level of diastolic blood pressure at baseline. A greater fitness level ( O2max) was moderately correlated with a lower BMI Z-score following the 12-week intervention. There was no difference between pre- and post-intervention habitual physical activity. A trend towards less sedentary time and increased light intensity activity was found, but these did not reach significance. Physical fitness level showed a trend for improvement following the intervention (P = 0.060). Anthropometrically determined body composition and body fat distribution did not change following the intervention. Radiologically determined abdominal adipose tissue depots were not significantly different post-intervention. % BF was not different when assessed with bioelectrical impedance analysis. However, % BF did reduce significantly over the 12-week intervention period when quantified by hydrometry (42.3% ± 5.0 vs 36.9% ± 8.6, P = 0.022). Adipokines, the secretory products of adipocytes displaying pleiotropic metabolic action, were investigated for their relation to lipid depots and additionally for change post-intervention. Cardiovascular (CV) disease risk was investigated by proatherogenic and protective blood lipids. When examined at baseline, fasting blood triacylglycerols (TAG) were inversely associated with basal and stimulated insulin sensitivity. Post-intervention, a higher level of HDL-C was found to be associated with greater insulin sensitivity, although this was not apparent at baseline. The relation between TAG and insulin sensitivity discovered pre-intervention was no longer evident. All other biomarkers of CV risk were not associated with body composition, glucose homeostasis, and lifestyle factors pre- and post-intervention. The effect of the physical activity intervention on indicators of haemostasis, physical fitness, blood lipids and lipoproteins, systemic inflammation, and fibrinolytic activity were analysed for change. Both systolic and diastolic blood pressure were significantly reduced following the physical activity programme. There was no significant difference found in any other measured parameter of CV risk. Log[HOMA], a surrogate index of insulin resistance, was significantly decreased post-intervention indicating reduced insulin resistance. QUICKI, a surrogate index of insulin sensitivity, was significantly improved post-intervention. The remaining indicators of insulin resistance, insulin sensitivity and β-cell function based on fasting surrogates did not significantly change over the 12-week experimental period. Dynamic insulin sensitivity and β-cell function were investigated pre- and post-intervention using paired samples t-tests. Glucose and insulin area under the curve of the OGTT were significantly reduced and whole-body insulin sensitivity index (WBISI) was significantly increased hence showing an improvement in stimulated insulin sensitivity. AUCCP/AUCglu significantly declined also indicating an improved response to oral glucose stimulation. IGI and ΔCP30/ΔG30, as markers of β-cell insulin secretion, did not change. Disposition index, the interrelationship of insulin secretion (IGI) and insulin sensitivity (WBISI), was not changed pre- and post-intervention. Hepatic insulin extraction was increased post-intervention (4.3 ± 1.2 vs 4.8 ± 1.1, P = 0.022) possibly due to greater hepatic and/or peripheral insulin sensitivity. General linear modeling (GLM) showed the improvement in whole-body insulin sensitivity discovered following the intervention was independent of % BF, abdominal adipose tissue depots, and ectopic lipid depots. Intrahepatocellular lipids (IHCL) significantly decreased after the 12-week intervention (6.99% ± 9.41 vs 5.83% ± 8.54) whilst there was no significant change in the serum markers of liver inflammation. IHCL was positively and strongly associated with total abdominal adipose tissue, intra-abdominal adipose tissue and subcutaneous abdominal adipose tissue both before and after the intervention. IHCL was positively associated with %BF measured post-intervention; this relationship almost reached significance when measured pre-intervention (P = 0.060). IHCL was not associated with insulin sensitivity either pre- or post-intervention nor with circulating lipids at either timepoint. The change in IHCL was independent of % BF and abdominal adipose tissue tested by GLM. However, there was no significant difference found in IHCL post-intervention after adjustment for insulin sensitivity (WBISI) by GLM. Prior to intervention, 10 of 15 subjects had hepatic steatosis diagnostic of non-alcoholic fatty liver disease. Eight of the 10 subjects with clinically significant hepatic steatosis had reduction of fatty infiltrate following the exercise intervention. In the whole group it was demonstrated that physical activity attenuates lipid infiltration of the liver independent of body fat. To further investigate the pathophysiology of ectopic lipid depots, biomarkers of oxidative stress and anti-oxidant status were examined in relation to IHCL. Pre-intervention, there was no association found between pro-oxidative or anti-oxidative activity and IHCL. Post-intervention, an inverse association of plasma carotenoid:cholesterol ratio with IHCL was found. Skeletal intramyocellular lipids (IMCL) measured in the right soleus were significantly increased post-intervention (2.4 ± 1.1 vs 2.6 ± 1.2, P = 0.035). There was no association between IMCL and % BF when measured pre- or post-intervention. Abdominal adipose depots were associated with IMCL at baseline and following the intervention. IMCL was not related to IHCL at either timepoint. Pre-intervention, there was a trend for a relationship between IMCL and insulin. Post-intervention, IMCL was tightly and inversely correlated with insulin sensitivity (r = -0.85 P = 0.000). Linear regression between IMCL and WBISI run pre-intervention and post-intervention found the slopes were not significantly different whereas the intercepts were highly significantly different (P = 0.001), thus, as IMCL increased there was a corresponding decrease in insulin sensitivity. GLM found the increase in IMCL was independent of % BF and abdominal adipose tissue, but was not independent of WBISI. These data indicate the greater IMCL level found post-intervention was a non-pathologic training adaptation. To further investigate the pathophysiology of ectopic lipid depots, biomarkers of oxidative stress and anti-oxidant status were examined in relation to IMCL. Pre-intervention, there was a positive association between malondialdehyde and IMCL. Post-intervention, an inverse association was found between IMCL and both plasma total carotenoids and total carotenoid:free cholesterol ratio. In summation, this study found improved metabolic health in obese, prepubertal children following a 12-week physical activity intervention without dietary intervention or intentional weight loss. Body fat and fat distribution were not prime mediators for the effect of the intervention on parameters of the Metabolic Syndrome; whereas insulin sensitivity was discovered to be a mediator of the change shown in ectopic fat depots. Causality and directionality of these fascinating relationships cannot be determined from the present study, and further research is encouraged. This thesis offers an insight into the pathogenesis of MetSyn and the use of physical activity to improve MetSyn in the setting of paediatric obesity.

Abstract Metabolic Syndrome (MetSyn) is a medical condition prevalent in Australia. MetSyn is diagnosed with a varying combination of visceral obesity, insulin resistance/ impaired glucose tolerance/ Type 2 diabetes, dyslipidaemia and hypertension. Obesity is a central feature of this syndrome that is characterised by abnormalities in glucose and lipid metabolism. An understanding of the cause of the metabolic derangement that occurs in obesity, and that contributes to MetSyn, would allow effective treatment and prevention strategies to be formulated. This is a priority in the current environment of highly prevalent overweight and obesity in Australian children and adults. Lipotoxicity of insulin-dependent tissues and ectopic fat depots are emerging as fundamental processes in the pathogenesis of MetSyn. Lifestyle intervention, such as increased physical activity, show great promise as agents for disrupting the disease progression and may act via direct or indirect mechanisms on the underlying pathology of MetSyn. This study aimed to determine if diagnostic markers of MetSyn exist in obese, prepubertal, Australian children and to assess the contribution of lifestyle factors on components of MetSyn. Further, this study sought to investigate the relationship between body fat patterning (total body fat, abdominal adipose depots, skeletal intramyocellular lipids, intrahepatocellular lipids) and markers of MetSyn. An experimental intervention was then employed to examine the effect of physical activity on body fat distribution, insulin sensitivity, and haemodynamic and biochemical markers of MetSyn, and additionally to determine if the effect of exercise on parameters of MetSyn was mediated by a change in body fat patterning. Data were collected in a group of 15 obese (mean BMI Z-score 2.51 ± 0.49), prepubertal children (6 male, 9 female) aged 5.1 – 11.4 years (mean age 7.82 yrs ± 1.83). Measures included insulin sensitivity, blood biochemistry (lipid, haemostatic and adipocyte activity markers), blood pressure, two-compartment body composition by hydrometry, and nuclear magnetic resonance scanning for abdominal adipose depots, intrahepatic lipids and skeletal intramyocellular lipids. Each child’s habitual nutrition and physical activity were also ascertained using multiple-pass 24-hr diet recalls and accelerometry respectively. Data collection was conducted pre and post a 12-week physical activity intervention which consisted of cardiorespiratory activity during instructor led sessions (60 mins, twice weekly) and family led sessions (>10 mins, 4 days/wk). There is no universally accepted definition of MetSyn in childhood. The International Diabetes Federation suggests that MetSyn should not be diagnosed in children aged 6 to < 10 years. Children can be identified to be at risk of MetSyn, however, based on waist circumference ≥90th percentile and family history1,2; all subjects in this study were at risk according to these criteria. Four definitions of paediatric MetSyn previously applied to a group of young, overweight Australian children3 were used to calculate the prevalence of MetSyn in the current sample and it was found to be 27-89% at baseline and 13-80% after the experimental intervention depending upon the definition used. Acanthosis nigricans and impaired glucose tolerance (IGT) were present in one female child. Post-intervention, IGT had resolved and the child was glucose tolerant. Habitual dietary intake (energy intake and macronutrients) measured over a 3-day period pre-intervention displayed a significant positive association between fasting glucose and energy intake, as well as a significant negative association between fasting glucose and the protein component of the diet. Following the physical activity programme, energy intake was significantly positively correlated with body fat percentage (% BF). There was no difference found in dietary intake assessed prior to and following cessation of the physical activity intervention, in terms of energy or % energy from macronutrients. Habitual physical activity was not related to MetSyn diagnostic indicators. A higher level of physical fitness, estimated by predicted O2max (ml•kg-1•min-1), was significantly correlated with a lower level of diastolic blood pressure at baseline. A greater fitness level ( O2max) was moderately correlated with a lower BMI Z-score following the 12-week intervention. There was no difference between pre- and post-intervention habitual physical activity. A trend towards less sedentary time and increased light intensity activity was found, but these did not reach significance. Physical fitness level showed a trend for improvement following the intervention (P = 0.060). Anthropometrically determined body composition and body fat distribution did not change following the intervention. Radiologically determined abdominal adipose tissue depots were not significantly different post-intervention. % BF was not different when assessed with bioelectrical impedance analysis. However, % BF did reduce significantly over the 12-week intervention period when quantified by hydrometry (42.3% ± 5.0 vs 36.9% ± 8.6, P = 0.022). Adipokines, the secretory products of adipocytes displaying pleiotropic metabolic action, were investigated for their relation to lipid depots and additionally for change post-intervention. Cardiovascular (CV) disease risk was investigated by proatherogenic and protective blood lipids. When examined at baseline, fasting blood triacylglycerols (TAG) were inversely associated with basal and stimulated insulin sensitivity. Post-intervention, a higher level of HDL-C was found to be associated with greater insulin sensitivity, although this was not apparent at baseline. The relation between TAG and insulin sensitivity discovered pre-intervention was no longer evident. All other biomarkers of CV risk were not associated with body composition, glucose homeostasis, and lifestyle factors pre- and post-intervention. The effect of the physical activity intervention on indicators of haemostasis, physical fitness, blood lipids and lipoproteins, systemic inflammation, and fibrinolytic activity were analysed for change. Both systolic and diastolic blood pressure were significantly reduced following the physical activity programme. There was no significant difference found in any other measured parameter of CV risk. Log[HOMA], a surrogate index of insulin resistance, was significantly decreased post-intervention indicating reduced insulin resistance. QUICKI, a surrogate index of insulin sensitivity, was significantly improved post-intervention. The remaining indicators of insulin resistance, insulin sensitivity and β-cell function based on fasting surrogates did not significantly change over the 12-week experimental period. Dynamic insulin sensitivity and β-cell function were investigated pre- and post-intervention using paired samples t-tests. Glucose and insulin area under the curve of the OGTT were significantly reduced and whole-body insulin sensitivity index (WBISI) was significantly increased hence showing an improvement in stimulated insulin sensitivity. AUCCP/AUCglu significantly declined also indicating an improved response to oral glucose stimulation. IGI and ΔCP30/ΔG30, as markers of β-cell insulin secretion, did not change. Disposition index, the interrelationship of insulin secretion (IGI) and insulin sensitivity (WBISI), was not changed pre- and post-intervention. Hepatic insulin extraction was increased post-intervention (4.3 ± 1.2 vs 4.8 ± 1.1, P = 0.022) possibly due to greater hepatic and/or peripheral insulin sensitivity. General linear modeling (GLM) showed the improvement in whole-body insulin sensitivity discovered following the intervention was independent of % BF, abdominal adipose tissue depots, and ectopic lipid depots. Intrahepatocellular lipids (IHCL) significantly decreased after the 12-week intervention (6.99% ± 9.41 vs 5.83% ± 8.54) whilst there was no significant change in the serum markers of liver inflammation. IHCL was positively and strongly associated with total abdominal adipose tissue, intra-abdominal adipose tissue and subcutaneous abdominal adipose tissue both before and after the intervention. IHCL was positively associated with %BF measured post-intervention; this relationship almost reached significance when measured pre-intervention (P = 0.060). IHCL was not associated with insulin sensitivity either pre- or post-intervention nor with circulating lipids at either timepoint. The change in IHCL was independent of % BF and abdominal adipose tissue tested by GLM. However, there was no significant difference found in IHCL post-intervention after adjustment for insulin sensitivity (WBISI) by GLM. Prior to intervention, 10 of 15 subjects had hepatic steatosis diagnostic of non-alcoholic fatty liver disease. Eight of the 10 subjects with clinically significant hepatic steatosis had reduction of fatty infiltrate following the exercise intervention. In the whole group it was demonstrated that physical activity attenuates lipid infiltration of the liver independent of body fat. To further investigate the pathophysiology of ectopic lipid depots, biomarkers of oxidative stress and anti-oxidant status were examined in relation to IHCL. Pre-intervention, there was no association found between pro-oxidative or anti-oxidative activity and IHCL. Post-intervention, an inverse association of plasma carotenoid:cholesterol ratio with IHCL was found. Skeletal intramyocellular lipids (IMCL) measured in the right soleus were significantly increased post-intervention (2.4 ± 1.1 vs 2.6 ± 1.2, P = 0.035). There was no association between IMCL and % BF when measured pre- or post-intervention. Abdominal adipose depots were associated with IMCL at baseline and following the intervention. IMCL was not related to IHCL at either timepoint. Pre-intervention, there was a trend for a relationship between IMCL and insulin. Post-intervention, IMCL was tightly and inversely correlated with insulin sensitivity (r = -0.85 P = 0.000). Linear regression between IMCL and WBISI run pre-intervention and post-intervention found the slopes were not significantly different whereas the intercepts were highly significantly different (P = 0.001), thus, as IMCL increased there was a corresponding decrease in insulin sensitivity. GLM found the increase in IMCL was independent of % BF and abdominal adipose tissue, but was not independent of WBISI. These data indicate the greater IMCL level found post-intervention was a non-pathologic training adaptation. To further investigate the pathophysiology of ectopic lipid depots, biomarkers of oxidative stress and anti-oxidant status were examined in relation to IMCL. Pre-intervention, there was a positive association between malondialdehyde and IMCL. Post-intervention, an inverse association was found between IMCL and both plasma total carotenoids and total carotenoid:free cholesterol ratio. In summation, this study found improved metabolic health in obese, prepubertal children following a 12-week physical activity intervention without dietary intervention or intentional weight loss. Body fat and fat distribution were not prime mediators for the effect of the intervention on parameters of the Metabolic Syndrome; whereas insulin sensitivity was discovered to be a mediator of the change shown in ectopic fat depots. Causality and directionality of these fascinating relationships cannot be determined from the present study, and further research is encouraged. This thesis offers an insight into the pathogenesis of MetSyn and the use of physical activity to improve MetSyn in the setting of paediatric obesity.

Orientador: Antonio Carlos Caramori / Resumo: A obesidade representa um dos maiores problemas de saúde pública no mundo e cursa com inúmeras complicações e comorbidades. As medidas de mudanças no estilo de vida, embora sejam as terapias mais duradouras, não têm conseguido resolver muitos casos, principalmente em pacientes com obesidade mórbida, onde a cirurgia bariátrica passa a ser uma opção no tratamento capaz de impedir a progressão de comorbidades. A DHGNA, uma das complicações da obesidade, tornou-se também preocupante, pois tem alta prevalência, potencial de progressão para doença hepática grave e associação com diabetes mellitus tipo 2 (DM2), síndrome metabólica e doença cardíaca coronariana. O acompanhamento multiprofissional, principalmente nutricional, no pré e pós-operatório pode positivamente interferir sobre a ocorrência da DHGNA e suas complicações. O presente estudo avaliou a influência do acompanhamento com equipe multiprofissional sobre a evolução da DHGNA, com dados coletados dos prontuários de 76 pacientes do Ambulatório de Obesidade Mórbida do Hospital das Clínicas da Faculdade de Medicina de Botucatu (HCFMB). A DHGNA foi observada por ecografia e biópsia hepática (em graus variados) nos pacientes submetidos à cirurgia bariátrica, cuja intensidade e frequência tiveram melhora no pós-operatório. Qualitativamente os registros da equipe demonstraram um atendimento humanizado que busca estratégias de aconselhamento, auxiliando o paciente nas mudanças do estilo de vida, porém, a atuação da mesma no serviço... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Obesity represents one of the major public health issues in the world and has a wide range of complications and comorbidities. The measures of lifestyle changes, even though they are the most long-lasting therapies, have not been able to solve many cases, mainly in patients with morbid obesity, where bariatric surgery becomes an option in the treatment able to prevent the progression of comorbidities. NAFLD, one of the complications of obesity, has also become a concern, as it has a high prevalence, a potential for progression to severe liver disease and association with type 2 diabetes mellitus (DM2), metabolic syndrome, and coronary heart disease. The multi-professional, mainly nutritional monitoring, both in the pre-and postoperative periods can positively interfere with the occurrence of NAFLD and its complications. The present study evaluated the influence of follow-up with the multi-professional team on the evolution of NAFLD, with data collected from the medical reports of 76 patients from the Morbid Obesity Outpatient Clinic of the Hospital das Clínicas da Faculdade de Medicina de Botucatu (HCFMB). NAFLD was observed by echography and liver biopsy (to varying degrees) in patients undergoing bariatric surgery, whose intensity and frequency had improvement in the postoperative period. Qualitatively, the team records have shown a humanized service which seeks counseling strategies, assisting the patient in lifestyle changes. However, its performance in the studied servic... (Complete abstract click electronic access below) / Mestre