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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

Alcoholic steatosis (AS) is the initial pathology associated with early stage alcoholic liver disease and is characterized by the accumulation of fat in the liver. AS is considered clinically benign as it is reversible, as compared with alcoholic steatohepatitis (ASH) which is the next stage of alcoholic liver disease (ALD), and mostly irreversible. Proteomics were used to investigate the molecular basis of AS to determine biomarkers representative of AS. Liver tissue proteins at different stages of steatosis from a rodent model of AS were separated by two dimensional electrophoresis (2DE), followed by MALDI mass spectrometry (MS) identification of significantly expressed proteins. Expression levels of several proteins related to alcohol induced oxidative stress, such as peroxiredoxin 6 (PRDX6) and aldehyde dehydrogenase 2 (ALDH2) were reduced by 2 to 3-fold in ethanol fed rats, and suggested an increase in oxidative stress. Several proteins involved in fatty acid and amino acid metabolism were found at increased expression levels, suggesting higher energy demand upon chronic exposure to ethanol. In order to delineate between the effects of fat accumulation and oxidative stress, an in vitro hepatocyte cell culture model of steatosis was developed. HepG2 cells loaded with oleic acid surprisingly demonstrated lower cytotoxicity upon oxidative challenge (based on lactate dehydrogenase activity) and inflammation (based on TNF-? induced activation of the pro-inflammatory transcription factor NF-?B). We also examined the effect of oleic acid loading in HepG2 cells on protein carbonylation, which is an important irreversible protein modification during oxidative stress that leads to protein dysfunction and disease. Fat-loaded hepatocytes exposed to oxidative stress with tert-butyl hydroperoxide (TBHP) contained 17% less carbonylated proteins than the non-fat loaded control. Mass spectrometric analysis of carbonylated proteins indicated that known classical markers of protein carbonylation (e.g., cytoskeletal proteins, chaperones) are not carbonylated in oleic acid loaded HepG2 cells, and suggests that the protective effect of fat loading is through interference with protein carbonylation. While counterintuitive to the general concept that AS increases oxidative stress, our fat loading results suggests that low levels of fat may activate antioxidant pathways and ameliorate the effect of subsequent oxidative or inflammatory challenge.

Alcoholic steatosis (AS) is the initial pathology associated with early stage alcoholic liver disease and is characterized by the accumulation of fat in the liver. AS is considered clinically benign as it is reversible, as compared with alcoholic steatohepatitis (ASH) which is the next stage of alcoholic liver disease (ALD), and mostly irreversible. Proteomics were used to investigate the molecular basis of AS to determine biomarkers representative of AS. Liver tissue proteins at different stages of steatosis from a rodent model of AS were separated by two dimensional electrophoresis (2DE), followed by MALDI mass spectrometry (MS) identification of significantly expressed proteins. Expression levels of several proteins related to alcohol induced oxidative stress, such as peroxiredoxin 6 (PRDX6) and aldehyde dehydrogenase 2 (ALDH2) were reduced by 2 to 3-fold in ethanol fed rats, and suggested an increase in oxidative stress. Several proteins involved in fatty acid and amino acid metabolism were found at increased expression levels, suggesting higher energy demand upon chronic exposure to ethanol. In order to delineate between the effects of fat accumulation and oxidative stress, an in vitro hepatocyte cell culture model of steatosis was developed. HepG2 cells loaded with oleic acid surprisingly demonstrated lower cytotoxicity upon oxidative challenge (based on lactate dehydrogenase activity) and inflammation (based on TNF-? induced activation of the pro-inflammatory transcription factor NF-?B). We also examined the effect of oleic acid loading in HepG2 cells on protein carbonylation, which is an important irreversible protein modification during oxidative stress that leads to protein dysfunction and disease. Fat-loaded hepatocytes exposed to oxidative stress with tert-butyl hydroperoxide (TBHP) contained 17% less carbonylated proteins than the non-fat loaded control. Mass spectrometric analysis of carbonylated proteins indicated that known classical markers of protein carbonylation (e.g., cytoskeletal proteins, chaperones) are not carbonylated in oleic acid loaded HepG2 cells, and suggests that the protective effect of fat loading is through interference with protein carbonylation. While counterintuitive to the general concept that AS increases oxidative stress, our fat loading results suggests that low levels of fat may activate antioxidant pathways and ameliorate the effect of subsequent oxidative or inflammatory challenge.

Made available in DSpace on 2015-04-17T15:02:52Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1302031 bytes, checksum: 9bb84ae976d2683e33dbac1994457636 (MD5) Previous issue date: 2012-03-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Nonalcoholic fatty liver disease (NAFLD) in the last two decades has been recognized as the most common chronic liver disease in Western countries, paralleling the epidemic of obesity and consumption of high-fructose diet. Researchers suggest that NAFLD may be the hepatic manifestation of metabolic syndrome. Although NAFLD and hyperuricemia are strongly related to metabolic syndrome, few scientists in the literature associated with both diseases. Allopurinol, a potent inhibitor of xanthine oxidase, with anti-inflammatory and antioxidant effects has been shown to prevent the metabolic syndrome induced by fructose. Thus, the main objective of the study is to evaluate the effects of allopurinol in the treatment of nonalcoholic steatohepatitis (NASH) and hyperglycemia in rats fed high-fructose water. Wistar rats were fed along with 20% fructose in drinking water with or without allopurinol (30mg/kg/day) for 14 weeks. A control group received a normal diet. Serum total cholesterol level (P<0,001) and glucose (P<0,05) in fructose group and of triglycerides (P<0,01) and creatinine (P<0,01) in allopurinol group were significantly increased compared to normal control. Significant correlations were found glucose with uric acid (r = 0.51, p <0.001) and creatinine with triglycerides (r = 0.354, p <0.05). Liver histopathology from fructose group showed mild to moderate, steatosis, necroinflammation and fibrosis. Allopurinol treatment decreases macrovesicular steatosis (27%, P<0,01), necroinflammation (72%, P<0,001) and fibrosis (26%, P<0,05) in hepatocytes. Therapy with allopurinol significantly prevented hyperglycemia and increased HDL cholesterol levels in rats and was effective in preventing necroinflammation and fructose-induced hepatic fibrosis. This is the first study to prove the action of a xanthine oxidase inhibitor as a treatment for NASH. / Nas últimas duas décadas a doença hepática gordurosa não alcoólica (DHGNA) tem sido reconhecida como a doença hepática crônica mais comum nos países ocidentais, em paralelo com a epidemia de obesidade e consumo de dieta com alto teor de frutose. Pesquisadores sugerem que DHGNA possa ser a manifestação hepática da síndrome metabólica. Apesar da EHNA e hiperuricemia estarem fortemente relacionadas com a síndrome metabólica, poucos cientistas na literatura consultada associaram as duas patologias. Alopurinol, um potente inibidor da xantina-oxidase, com efeito anti-inflamatório e antioxidante tem sido utilizado para prevenir a síndrome metabólica induzida por frutose. Assim, o objetivo principal do presente estudo é avaliar os efeitos do alopurinol na prevenção da esteatose hepática não alcoólica (EHNA) e hiperglicemia em ratos alimentados com água rica em frutose. Ratos Wistar foram alimentados com 20% de frutose na água de beber, com ou sem alopurinol (30mg/kg/dia) durante 14 semanas. Um grupo controle recebeu uma dieta normal. Níveis de colesterol total (P <0,001) e glicose (P <0,05) no grupo de frutose e de triglicérides (P <0,01) e creatinina (P <0,01) no grupo alopurinol foram significativamente mais elevados, em comparação com o controle normal. As correlações significativas encontradas foram ácido úrico com glicose (r = 0,51, p<0,001) e creatinina com triglicerídeos (r = 0,354, p<0,05). A análise histopatológica hepática do grupo frutose mostrou esteatose, necroinflamação e fibrose de leve a moderada. O tratamento com alopurinol diminuiu esteatose macrovesicular (27%, P <0,01), necroinflamação (72%, P <0,001) e fibrose (26%, P <0,05) em hepatócitos. A terapia com alopurinol evitou significativamente a hiperglicemia e aumentou os níveis de HDL colesterol nos ratos e foi eficaz na prevenção da necroinflamação e fibrose hepática induzida por frutose. Corresponde assim ao primeiro estudo a provar a ação de um inibidor da xantina oxidase como um tratamento para EHNA.

La stéatose hépatique non alcoolique, regroupant la stéatose isolée (NAFLD) et la stéatohépatite non-alcoolique (NASH), est un enjeu de santé publique mondial en raison d’une incidence croissante, en grande partie expliquée par l’augmentation de la prévalence du diabète et de l’obésité. La stéatose hépatique prédit la survenue des complications métaboliques associées à l’insulinorésistance, comme le diabète ou les événements cardiovasculaires. La connaissance de l’histoire naturelle de la NAFLD comporte encore de nombreuses incertitudes. Actuellement le modèle explicatif repose sur une dichotomie entre la stéatohépatite (NASH), qui peut progresser vers la cirrhose et la stéatose isolée ou avec inflammation minime (NAFL) qui jusqu'à présent était considérée comme une condition non évolutive ne progressant pas vers la cirrhose et n'augmentant pas la morbi-mortalité d'origine hépatique. Cette dichotomie conditionne en grande partie la prise en charge de ces patients, ceux avec NAFL étant souvent rassurés par le praticien quant à leur devenir et ne bénéficiant pas d'une surveillance hépatique spécifique. La ponction biopsie du foie est considérée comme un examen de référence, mais son usage en pratique clinique reste limité en raison d’effets indésirables, d’erreurs d'échantillonnage et de la variabilité d’interprétation inter-observateur. Les méthodes non invasives de lésions hépatiques sont devenues une vraie alternative à la biopsie du foie pour la prise en charge des patients ayant une maladie chronique du foie, au cours des dix dernières années. / Non-alcoholic fatty liver disease (NAFLD) covers a spectrum ranging from isolated steatosis to non-alcoholic steatohepatitis (NASH) and is becoming one of the most frequent causes of chronic liver disease, mainly because of its close association with the worldwide epidemic of diabetes and obesity. Liver steatosis can predict the occurrence of metabolic complications associated with insulin resistance, such as diabetes and cardiovascular events. Our understanding of the natural history of NAFLD is still incomplete. Currently, the explicative model is based on a dichotomy between steatohepatitis, considered the progressive form of the disease, which can lead to cirrhosis and isolated steatosis with or without minimal inflammation, which is considered a non-progressive condition that does not impact overall survival or result in liver-related mortality and morbidity. This dichotomy largely determines the management of NAFLD patients: patients without steatohepatitis usually do not undergo specific monitoring for liver disease progression. Liver biopsy is considered the reference diagnostic method but its implementation in clinical practice remains limited due to procedure complexity, invasiveness, cost, potential complications, sampling error and inter-observer variability. Non-invasive methods of hepatic injury have become a real alternative to liver biopsy for the diagnosis of patients with chronic liver disease in the past decade. The aims of this thesis were: 1) to better understand the histological course of the disease, to better identify patients at risk of histological progression based on initial histological findings and to establish a correlation between histological changes and the course of metabolic co-morbidities often associated with NAFLD : 2) to establish factors associated with short-term variability of repeated measurements of elastometry in patients with chronic liver diseases in order to understand how this non invasive procedure can be used for patient monitoring 3) to determine the diagnostic value and limitations of several steatosis biomarkers using liver biopsy as a reference standard in a large cohort of patients with suspected NAFLD. Our study shows that a fraction of patients with isolated steatosis can unambiguously evolve towards well-defined steatohepatitis, and in some of them, bridging fibrosis. The presence of mild lobular inflammation or any amount of fibrosis substantially increases the risk of histological progression in the mid-term while those with steatosis alone are at lowest risk. Patients with disease progression experienced a deterioration of cardio-metabolic risk factors. Our data if validated by independent studies, allow for better stratification of patients at risk of disease progression. The results of this study favor a change in the practices of monitoring and risk assessment of patients with steatosis but without steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is a severe liver disorder characterized by triglyceride accumulation, severe inflammation, and fibrosis. With the recent increase in prevalence, NASH is now the leading cause of liver transplantation, with no approved therapeutics available. Despite years of research, the exact molecular mechanism of NASH progression is not well understood, but fat accumulation is believed to be the primary driver of the disease. Therefore, diacylglycerol O-acyltransferase 2 (DGAT2), a key enzyme in triglyceride synthesis, has been explored as a NASH target. RNAi-based therapeutics is revolutionizing the treatment of liver diseases, with recent chemical advances supporting long term gene silencing with single subcutaneous administration. Here we identified a hyper-functional, fully chemically stabilized GalNAc conjugated siRNA targeting DGAT2 (Dgat2-1473) that upon injection elicits up to three months of DGAT2 silencing (>80-90%, p<0.0001) in wild-type and NSG-PiZ “humanized” mice. Using an obesity-driven mouse model of NASH (ob/ob-GAN), Dgat2-1473 administration prevents and reverses triglyceride accumulation (> 50%, p:0.0008), resulting in significant improvement of the fatty liver phenotype. However, surprisingly, the reduction in liver fat didn’t translate into a similar impact on inflammation and fibrosis. Thus, while Dgat2-1473 is a practical, long-lasting silencing agent for potential therapeutic attenuation of liver steatosis, combinatorial targeting of a second pathway may be necessary for therapeutic efficacy against NASH.

Patients with type 2 diabetes (T2D) are at risk for non-alcoholic fatty liver disease (NAFLD) and associated complications. This study evaluated the performance of international (EASL-EASD-EASO) and national (DGVS) guidelines for NAFLD risk stratification. Patients with T2D prospectively underwent ultrasound, liver stiffness measurement (LSM) and serum-based fibrosis markers. Guideline-based risk classification and referral rates for different screening approaches were compared and the diagnostic properties of simplified algorithms, genetic markers and a new NASH surrogate (FAST score) were evaluated. NAFLD risk was present in 184 of 204 screened patients (age 64.2 ± 10.7 years; BMI 32.6 ± 7.6 kg/m2). EASL-EASD-EASO recommended specialist referral for 60–77% depending on the fibrosis score used, only 6% were classified as low risk. The DGVS algorithm required LSM for 76%; 25% were referred for specialised care. The sensitivities of the diagnostic pathways were 47–96%. A simplified referral strategy revealed a sensitivity/specificity of 46/88% for fibrosis risk. Application of the FAST score reduced the referral rate to 35%. This study (a) underlines the high prevalence of fibrosis risk in T2D, (b) demonstrates very high referral rates for in-depth hepatological work-up, and (c) indicates that simpler referral algorithms may produce comparably good results and could facilitate NAFLD screening.