Submitted by PAULA ALVES MONTEIRO null (paulinha__1003@hotmail.com) on 2017-04-19T18:50:37Z No. of bitstreams: 1 Tese 19.04.2017.pdf: 2395576 bytes, checksum: e734bebf2444db011375c3dd59d51838 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-04-19T20:03:53Z (GMT) No. of bitstreams: 1 monteiro_pa_dr_rcla.pdf: 2395576 bytes, checksum: e734bebf2444db011375c3dd59d51838 (MD5) / Made available in DSpace on 2017-04-19T20:03:53Z (GMT). No. of bitstreams: 1 monteiro_pa_dr_rcla.pdf: 2395576 bytes, checksum: e734bebf2444db011375c3dd59d51838 (MD5) Previous issue date: 2016-11-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A prevalência da obesidade na população pediátrica aumenta a um ritmo acelerado em muitos países, e tem se tornado um importante problema de saúde pública. O exercício físico (crônico e agudo) continua sendo uma pedra angular nas intervenções com a população pediátrica obesa. Assim, o objetivo do estudo foi investigar o efeito de modelos distintos de exercício físico agudo e crônico na composição corporal, variáveis metabólicas e resposta dos marcadores inflamatórios em adolescentes obesos com ou sem esteatose hepática (EH). Materiais e Métodos: Estudo crônico - 32 adolescentes obesos participaram de dois grupos de treinamento randomizados, concorrente ou aeróbico durante 20 semanas (50 minutos x 3 por semana), e foram comparados a um grupo controle de 16 sujeitos. Estudo Agudo - 19 adolescentes obesos realizaram duas sessões experimentais, separadas por uma semana, Exercício Intermitente de Intensidade Moderada (EIIM) (3 min: 1 min a 65% velocidade máxima atingida durante o teste de esteira, totalizando ~ 3 km) e Exercício Intermitente de Alta Intensidade (EIAI) (2 min: 1 min a 95% da velocidade máxima alcançada durante o teste de esteira, totalizando ~ 3 km). Ambos os estudos mensuraram a composição corporal dos voluntários utilizando-se a absortometria de raio-x de dupla energia, perfil metabólico e inflamatório, bem como o diagnóstico da EH e a espessura da gordura subcutânea e visceral utilizando-se o ultrassom. Resultados: No estudo crônico após 20 semanas, ambos os grupos de treinamento reduziram significativamente o % GC por 2,9-3,6% em comparação ao grupo controle que não obteve mudanças (p = 0,042). Houve também mudanças positivas no perfil lipídico dos grupos que treinaram. No entanto, as variáveis inflamatórias não se alteraram. Não houve diferença entre as mudanças dos grupos de treinamento aeróbio e concorrente. Já o estudo agudo houve alterações significativas no grupo EIAI com EH, no triacilglicerol (aumentou de 17,9%) e cortisol (aumentou 93,03%) e no grupo EIAI sem EH, houve alterações no triacilglicerol (aumentou de 10,6%), no cortisol (aumentou de 18,1%) e IL-6 (aumentou de 20,4%). No grupo EIIM com EH, houve alteração significativa apenas no cortisol (diminuição de 46,9%) e no grupo EIIM sem EH foram observadas alterações no triacilglicerol (aumento de 9,4%) e cortisol (diminuição de 41%). Concluímos que os treinamentos concorrente e aeróbio foram capazes de propiciar benefícios na composição corporal e nas variáveis metabólicas em adolescentes com e sem EH, e só o esforço aeróbio agudo de alta intensidade propiciou alterações inflamatórias nos adolescentes sem EH. / The prevalence of obesity in pediatric population is increasing at an accelerated rate in many countries, and has become a major public health concern. Physical activity, particularly exercise training (chronic and acute), remains to be a cornerstone of pediatric obesity interventions, and of diseases associated, such as the hepatic steatosis. Thus the aim of the study was analyze the effect of different types of exercise on body composition, metabolic variables and response of inflammatory mediators in obese adolescents with and without hepatic steatosis (HS). Materials and Methods: Chronic study - 32 obese adolescents participated in two randomized, concurrent or aerobic training groups for 20 weeks (50 minutes x 3 per week), and were compared to a control group of 16 subjects. Acute Study - 19 obese adolescents underwent two experimental sessions, separated by one week, Intermittent Exercise of Moderate Intensity (MIIE) (3 min: 1 min at 65% maximum speed reached during treadmill test, totalizing ~ 3 km) and Intermittent exercise (HIIE) (2 min: 1 min at 95% of the maximum speed reached during the treadmill test, totaling ~ 3 km). Both studies measured the body composition of the volunteers using dual-energy x-ray absorptiometry, metabolic and inflammatory profile, as well as the diagnosis of HS and the thickness of the subcutaneous and visceral fat using the ultrasound. Results: In the chronic study after 20 weeks, both training groups significantly reduced the % BF by 2.9-3.6% compared to the control group that did not change (p = 0.042). There were also positive changes in the lipid profile of the groups they trained. However, the inflammatory variables did not change. There was no difference between the changes in the aerobic and concurrent training groups. In the acute study, there were significant alterations in the triacylglycerol (increased from 17.9%) and cortisol (93.03%) and in the HIIE group without HS), Cortisol (increased by 18.1%) and IL-6 (increased by 20.4%). In the MIIE group with HS, there was a significant change only in cortisol (46.9% decrease) and in the MIIE group without HS, changes in triacylglycerol (increase of 9.4%) and cortisol (decrease of 41%) were observed. We conclude that concurrent and aerobic training were able to provide benefits in body composition and metabolic variables in adolescents with and without HS, and only the high intensity acute aerobic effort allowed for inflammatory and metabolic changes in adolescents without HS.

Introdução: A doença hepática alcóolica (DHA) e a doença hepática gordurosa não alcóolica (DHGNA) estão entre as principais causas de morte por doenças hepáticas no mundo. Apesar das etiologias distintas, sendo a DHA causada pelo consumo excessivo de álcool e a DHGNA por dieta inadequada e sedentarismo, apresentam curso de doença semelhante, que pode evoluir de esteatose, para esteato-hepatite, fibrose, cirrose e carcinoma hepatocelular. Tanto a DHA quanto a DHGNA estão relacionadas à disbiose, aumento de permeabilidade intestinal, inflamação e dano hepático. Entretanto, ainda não está claro se a doença hepática precede as alterações no epitélio intestinal ou se é o aumento da permeabilidade que promove o dano hepático. Objetivo: Avaliar a expressão gênica de Tight Junctions em modelo de DHA e DHGNA em zebrafish (Danio rerio). Métodos: No modelo de DHA, os peixes foram divididos em dois grupos: Etanol (n=30), expostos a 0,5% de etanol por 28 dias e controle (n=30). No modelo de DHGNA, os peixes foram divididos também em dois grupos: Frutose (n=24), expostos à frutose 6% durante 2 horas por 14 dias e controle (n=24). Ao término dos experimentos os animais foram eutanasiados e coletados fígados, para avaliação histológica por coloração hematoxilina-eosina (HE) e de esteatose por Oil Red, e intestinos para avaliação da expressão gênica dos marcadores de permeabilidade intestinal cldnC, cldn15a, cldn15b e f11r por Real Time qPcr. Resultados: Tanto os animais expostos ao álcool quanto à frutose apresentaram esteatose hepática por coloração HE e Oil Red quando comparados aos seus respectivos controles, sem sinais de infiltrados inflamatórios e de fibrose hepática à microscopia óptica. Não houve diferença significativa na expressão gênica das tight junctions intestinais, tanto para a DHA quanto DHGNA (p  0,05). Conclusão: Os resultados sugerem que em estágios iniciais de DHA e DHGNA não ocorre alteração da permeabilidade intestinal, e que possivelmente o dano hepático precede o dano intestinal. / Introduction: Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are among the leading causes of death from liver disease worldwide. Despite the different etiologies, ALD is caused by excessive alcohol consumption and NAFLD is due to inadequate diet and sedentary lifestyle, they have a similar disease course, which can progress from steatosis to steatohepatitis, fibrosis, cirrhosis and hepatocellular carcinoma. Both ALD and NAFLD are related to dysbiosis, increased gut permeability, inflammation, and liver damage. However, it is not yet clear whether liver disease precedes changes in the intestinal epithelium or whether it is the increased permeability that promotes liver damage. Objective: To evaluate the gene expression of tight junctions in ALD and NAFLD models in zebrafish (Danio rerio). Methods: In the ALD model, fish were divided into two groups: Ethanol (n=30), exposed to 0.5% ethanol for 28 days and control (n=30). In the NAFLD model, fish were also divided into two groups: Fructose (n=24), exposed to 6% fructose for 2 hours for 14 days and control (n=24). At the end of the experiments the animals were euthanized and livers were collected for histological evaluation by hematoxylin-eosin (HE) staining and steatosis by oil red staining and intestines for evaluation of the gene expression of gut permeability markers cldnC, cldn15a, cldn15b and f11r by Real Time qPcr. Results: Both animals exposed to alcohol and fructose presented hepatic steatosis by HE and Oil Red staining when compared to their respective controls, without signs of inflammatory infiltrates under optical microscopy. There was no significant difference in the gene expression of the tight junctions for both ALD and NAFLD (p0.05) Conclusion: The results suggest that in the early stages of ALD and NAFLD there are no changes in intestinal tight junctions, and that possibly liver damage precedes intestinal damage.

Orientadores: Gabriel Hessel, Antônio Azevedo Barros Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-23T14:11:58Z (GMT). No. of bitstreams: 1 Gobato_AmandaOliva_M.pdf: 1670320 bytes, checksum: 56fdc5f99e019be77ae96f2a44e8ebef (MD5) Previous issue date: 2013 / Resumo: Introdução: A prevalência da obesidade tem aumentado rapidamente nas ultimas décadas. A preocupação com a obesidade na infância e adolescência relaciona-se ao desenvolvimento das comorbidades e das complicações geradas pelo excesso de peso. A prevenção e vista como a melhor estratégia para reter o continua aumento da prevalência da obesidade. Objetivos: 1. Verificar a prevalência da síndrome metabólica (SM) e da resistência a insulina (RI) em adolescentes obesos e correlacioná-los aos diferentes indicadores bioquímicos, antropométricos e de composição corporal. 2. Descrever a prevalência da esteatose hepática (EH) diagnosticada por ultrassonografia abdominal (US) e avaliar o desempenho de indicadores bioquímicos, antropométricos e de composição corporal para identificar a esteatose hepática em adolescentes obesos. Métodos: Estudo transversal com 79 adolescentes obesos de 10 a 18 anos. A EH foi diagnosticada por US quando o contraste hepatorenal apresentava-se moderado ou intenso e/ou diferença no histograma >8 em relação ao córtex do rim direito. A SM foi diagnosticada segundo os critérios de Cook et al (2003) e a RI pelo índice de HOMA-IR para valores >3,16. Os indicadores antropométricos e de composição corporal avaliados foram: índice de massa corporal (IMC), % gordura corporal circunferência abdominal (CA) e gordura subcutânea. Foram dosadas as enzimas hepaticas: aspartato aminotransferase (AST), alanina aminotransferase (ALT), gama-glutamiltransferase (GGT) e fosfatase alcalina (FALC), glicemia e insulina de jejum e perfil lipidico. A analise de Curvas ROC foi utilizada para avaliar o desempenho dos indicadores antropométricos, bioquímicos e a % gordura corporal em identificar adolescentes com EH, o IMC e a CA em identificar a RI e a SM. Resultados: A SM foi diagnosticada em 45,5% dos pacientes e a RI em 29,1%. A RI apresentou associação com o HDL-colesterol e com a SM e se correlacionou com todos os indicadores antropométricos e de composição corporal avaliados. Na avaliação dos pontos de corte, os valores de 23,5 e 36,3% acima do valor de referencia do IMC mostraram-se capazes em identificar a RI e a SM. O melhor ponto de corte da CA para identificar a RI foi de 40%. A EH esteve presente em 16 pacientes (20,3%). A GGT e o HOMA-IR mostraram ser bons indicadores na predição da EH, com ponto de corte de 1,06 vezes acima do valor de referencia para a GGT e 3,28 para o HOMA-IR. Os indicadores antropométricos, % gordura corporal, perfil lipidico, glicemia e AST não apresentaram resultados significantes. Conclusão: A prevalência de EH em adolescentes obesos foi de 20,3%. Todos os indicadores antropométricos e de composição corporal avaliados apresentaram correlação com a RI e apenas o IMC se correlacionou com a SM. O IMC mostrou-se o indicador antropométrico mais efetivo na identificação da RI. Pacientes com elevação de GGT e/ou com HOMA-IR devem ser submetidos ao exame de US com grande probabilidade de se obter como resultado a EH / Abstract: Background: Obesity prevalence has increased rapidly in recent decades. The concern with obesity in childhood and adolescence is related to the development of comorbidities and complications generated by excess weight. Prevention is seen as the best strategy for retaining the continuous increase in obesity prevalence. Objectives: 1. to verify metabolic syndrome (MS) and insulin resistance (IR) prevalence in obese adolescents and correlate them with different biochemical, anthropometric and body composition indicators. 2. To describe hepatic steatosis (HS) prevalence diagnosed by abdominal ultrasound (AU) and evaluates the performance of biochemical, anthropometric and body composition indicators to identify hepatic steatosis in obese adolescents. Methods: A transversal study comprising 79 obese adolescents aged 10-18 years. HS was diagnosed by AU when hepatorenal contrast presented moderated or intense and/or there was a difference greater than 8 in relation to the right kidney cortex in histogram. MS was diagnosed according to the criteria by Cook et al (2003) and IR, by using the homeostatic model assessment (HOMA) index for values greater than 3.16. The following anthropometric and body composition indicators were evaluated: body mass index (BMI), body fat percentage, abdominal circumference (AC) and subcutaneous fat (SF). Hepatic enzymes - aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT) and alkaline phosphatase (FALC) -, glycemia, fasting insulin and lipid profile were measured. ROC Curve analysis was used for accessing the performance of biochemical, anthropometric and body composition indicators, which identified adolescents with HS; BMI and AC identified IR and MS. Results: MS was diagnosed in 45.5% of patients, and IR, in 29.1%. IR showed association with HDL-cholesterol and MS, correlating with all evaluated anthropometric and body composition indicators. In the evaluation of cutoff points, values of 23.5 and 36.3% above the BMI reference value showed capable of identifying IR and MS. The best cutoff point of AC to identify IR was of 40%. Sixteen patients (20.3%) were diagnosed with HS. GGT and HOMA-IR showed to be good indicators in predicting HS, with cutoff point of 1.06 times above the reference values for GGT and 3.28 for HOMA-IR. Anthropometric, body fat percentage, lipid profile, glycemia xi and AST did not present significant results. Conclusion: The HS prevalence in obese adolescents was of 20.3%. All evaluated anthropometric and body composition indicators presented correlation with IR, and only BMI showed correlation with MS. BMI showed to be the most effective anthropometric indicator in identifying IR. Patients with elevation of GGT and/or HOMA-IR should be submitted to US examination with great probability of obtaining HS as a result / Mestrado / Saude da Criança e do Adolescente / Mestra em Ciências

La prévalence de l’obésité et du diabète de type 2 est en constante augmentation dans les pays industrialisés. Ces pathologies sont associées à des troubles de l’équilibre énergétique de l’organisme, ce qui se traduit au niveau hépatique par le développement de NAFLD (Non‐alcoholic Fatty Liver Disease). La NAFLD est engendrée par l’accumulation excessive de lipides dans les hépatocytes ou stéatose et est associée à la résistance à l’insuline. L’insulinorésistance hépatique est dite sélective car l’insuline n’est plus capable d’inhiber la production hépatique de glucose, contribuant à l’hyperglycémie, alors que la synthèse lipidique est exacerbée, induisant une stéatose hépatique. La stéatose peut évoluer en pathologies plus graves, telles que la fibrose, la cirrhose ou le cancer hépatocellulaire (CHC). L’objectif de ma thèse a été d’étudier les mécanismes moléculaires pouvant contribuer à la sélectivité de la résistance à l’insuline hépatique et à l’évolution de la stéatose simple vers le CHC. Dans un premier temps, nous avons étudié le rôle de l’adaptateur moléculaire Grb14, un inhibiteur de l’activité kinase du récepteur de l’insuline, dans la régulation du métabolisme hépatique chez la souris. L’invalidation de Grb14 dans le foie conduit d’une part à une activation de la signalisation de l’insuline et une amélioration de tolérance au glucose, et d’autre part à une diminution de la lipogenèse consécutive à l’inhibition du facteur lipogénique LXR via la voie Nrf2. L’invalidation de Grb14 dans le foie de souris obèses et diabétiques permet de ramener la glycémie et la stéatose hépatique à des valeurs similaires aux témoins. Ces données suggèrent que Grb14 est un nouvel acteur impliqué dans la sélectivité de la résistance à l’insuline du foie. La seconde étude a permis de montrer l’implication de la stéatose hépatique induite par un régime hypercalorique sur le développement de CHC. En effet, sur un fond génétique favorisant la carcinogenèse, un régime riche en graisse et en sucre contribuant à l’insulinorésistance hépatique accélère la cinétique d’apparition des tumeurs et augmente leur nombre. / The prevalence of metabolic diseases, including obesity and type 2 diabetes, are expanding in a worldwide epidemic way. These diseases are associated with metabolic disorders, resulting in the development of NAFLD (Non‐alcoholic Fatty Liver Disease) in the liver. NAFLD is generated by excessive accumulation of lipids in hepatocytes, and is associated with insulin resistance. In liver, insulin resistance leads to a blunted inhibitory action on hepatic glucose production, inducing hyperglycemia, whereas de novo lipogenesis, which is positively regulated by insulin, is paradoxically exacerbated, contributing to hepatic steatosis. Steatosis may also evolve into more serious diseases such as fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The aim of my thesis was to study the molecular mechanisms that may contribute to the selectivity of hepatic insulin resistance and the development of HCC. Initially, we studied the role of the molecular adapter Grb14, an inhibitor of the insulin receptor kinase activity, in the regulation of hepatic metabolism in mice. Invalidation of Grb14 in the liver leads on the one hand to an activation of the insulin signaling and improved glucose tolerance, and on the other hand to a decrease of LXR activity resulting in lipogenesis inhibition. Invalidation of Grb14 in the liver of obese and diabetic mice restores blood glucose levels and hepatic steatosis similar to control values. These data suggest that Grb14 is a new player involved in the selectivity of the insulin resistance in the liver. The second study demonstrated the involvement of hepatic steatosis induced by a high‐calorie diet on the development of HCC. Indeed, on a genetic background favoring carcinogenesis, a diet rich in fat and sugar contributing to hepatic insulin resistance accelerates appearance of tumors and increases their number.

Indiana University-Purdue University Indianapolis (IUPUI) / Regulation of the pyruvate dehydrogenase complex (PDC) is important for glucose homeostasis and control of fuel selection by tissues. Knocking out pyruvate dehydrogenase kinase 4 (PDK4), one of four kinases responsible for regulation of PDC activity, lowers blood glucose levels by limiting the supply of three carbon compounds for gluconeogenesis. Down regulation of PDK4 expression is also important for control of blood glucose by insulin. The primary goal was to determine whether PDK4 should be considered a target for the treatment of diabetes. A major concern is that inhibition of fatty acid oxidation by PDK4 deficiency may promote fat accumulation in tissues and worsen insulin sensitivity. This was examined by feeding wild type and PDK4 knockout mice a diet rich in saturated fat. Fasting blood glucose levels were lower, glucose tolerance was better, insulin sensitivity was greater, and liver fat was reduced in PDK4 knockout mice. The reduction in liver fat is contradictory to the finding that fibrate drugs increase PDK4 expression but ameliorate hepatic steatosis in rodents. To investigate this phenomenon, wild type and PDK4 knockout mice were fed the high saturated fat diet with and without clofibric acid. The beneficial effect of clofibric acid on hepatic steatosis was greater in the PDK4 knockout mice, indicating up regulation of PDK4 is not necessary and likely opposes the effect of clofibric acid on hepatic steatosis. Clofibric acid dramatically lowered the amount of hepatic CD36, a plasma membrane translocase required for fatty acid import, suggesting a novel mechanism for prevention of hepatic steatosis by fibrates. PDK4 deficiency had no effect on CD36 expression but reduced the enzymatic capacity for fatty acid synthesis, suggesting clofibric acid and PDK4 deficiency ameliorate hepatic steatosis by independent mechanisms. Investigation of the mechanism by which insulin regulates PDK4 expression revealed a novel binding site for hepatic nuclear factor 4α (HNF4α) in the PDK4 promoter. The stimulatory effect of HNF4α was sensitive to inhibition by Akt which is activated by insulin. The findings suggest PDK4 is a viable target for the treatment of hepatic steatosis and type 2 diabetes.

No description available.

No description available.

No description available.

L’athérosclérose est un problème de santé publique majeur puisque elle représente aujourd’hui la principale cause de décès dans les pays occidentalisés. Il est donc important de comprendre les mécanismes participant à la progression et aux complications de cette entité anatomoclinique. Nous nous sommes attachés dans ce travail de thèse à démontrer la place et l’apport potentiel de l’imagerie non invasive non expérimentale dans la mise en exergue des particularités de l’athérosclérose carotidienne et/ou coronarienne, et dans la stratégie de dépistage de ses complications chez le sujet non diabétique et diabétique de type 2, en fonction de l’existence ou non d’une stéatose hépatique non alcoolique. Nous présentons notamment dans ce travail, issu en partie de l’exploitation des données cliniques, biologiques et radiologiques de trois protocoles hospitaliers de recherche clinique, les différentes publications scientifiques internationales auxquelles il a donné lieu. / Atherosclerosis is a major public health problem and is one of the major causes of death in the developed western world today. It is therefore of utmost importance that we understand the mechanisms involved in the evolution and progression of this disease and its associated complications. With the work done for this thesis, we tried to bring forth the importance of non invasive clinical imaging to study the pattern of evolution of atherosclerosis involving the carotid and/or coronary arteries. We also present the role played by imaging in prevention and early diagnosis of associated complications in non diabetic and type 2 diabetic patients, presenting with or without non alcoholic hepatic steatosis. In this study, we evaluated three different clinical research protocols used involving the clinical findings, biochemical as well as radiological examination results. The results of these protocols have been the basis for several peer reviewed international publications till date.

A esteatose hepática, que se caracteriza pelo acúmulo excessivo de gordura nas células do fígado, é um problema que vem preocupando a comunidade médico-científica, pois sua incidência vem aumentando a nível global, com expectativa de se tornar a doença crônica hepática de maior predominância em várias partes do mundo. Apesar de ser considerada uma doença benigna, a esteatose pode evoluir para doenças mais graves como cirrose, fibrose avançada, esteato hepatite (com ou sem fibrose) ou carcinoma. Entretanto, é potencialmente reversível, mesmo em quadros mais graves, o que reforça a urgência de se desenvolver métodos confiáveis para detecção e avaliação, inclusive ao longo de tratamento. Os métodos atuais para diagnóstico e quantificação da gordura hepática ainda são falhos: com a ultrassonografia não se é capaz de realizar quantificação; a tomografia computadorizada faz uso de radiação ionizante; a punção (biópsia), considerada o padrão ouro, é precisa, mas invasiva e pontual. A Ressonância Magnética (RM), tanto com espectroscopia (MRS) como com imagem (MRI), são alternativas completamente não invasivas, capazes de fornecer o diagnóstico e quantificação da gordura infiltrada no fígado. Entretanto, os trabalhos encontrados na literatura utilizam sequências de pulsos desenvolvidas especialmente para esse fim, com métodos de pós-processamento extremamente rebuscados, o que não é compatível com o estado atual dos equipamentos encontrados em ambientes clínicos nem mesmo ao nível de experiência e conhecimento das equipes técnicas que atuam em clínicas de radiodiagnóstico. Assim, o objetivo central do presente trabalho foi avaliar o potencial da RM como candidato a método de diagnóstico e de quantificação de gordura em ambientes clínicos, utilizando, para isso, sequências de pulsos convencionais, disponíveis em qualquer sistema comercial de RM, com protocolos de aquisição e processamento compatíveis com àqueles realizados em exames clínicos, tanto no que se refere à simplicidade como ao tempo total de aquisição. Foram avaliadas diferentes abordagens de MRS e MRI utilizando a biópsia hepática como padrão de referência. Foram avaliados pacientes portadores de diabetes tipo II, que apresentam alta prevalência de esteatose hepática não alcoólica, além de grande variabilidade nos percentuais de gordura. Foram realizadas medidas de correlação, acurácia, sensibilidade e especificidade de cada uma das abordagens utilizadas. Todos os métodos avaliados apresentaram alto grau de correlação positiva (> 87%) com os dados obtidos de maneira invasiva, o que revela que os valores obtidos utilizando RM estão de acordo com aquilo observado pela biópsia hepática. Muito embora os métodos de processamento utilizados não sejam tão complexos quanto seriam necessários caso uma quantificação absoluta fosse desejada, nossas análises mostraram alta acurácia, especificidade e sensibilidade da RM na avaliação da esteatose. Em conclusão, a RM se apresenta, de fato, como uma excelente candidata para avaliar, de forma não invasiva, a fração de gordura hepática, mesmo quando se considera as limitações impostas por um ambiente clínico convencional. Isso sugere que essas novas metodologias podem começar a migrar para ambientes clínicos sem depender das sequências complexas e dos processamentos exóticos que estão descritos na literatura mais atual. / Hepatic steatosis is a disease characterized by excessive accumulation of fat in liver cells. Its incidence is increasing and it is expected to become the chronic liver disease with the highest prevalence worldwide, which became a major concern to medical and scientific community. Although considered a benign disease, fatty liver can evolve to more serious diseases such as cirrhosis, advanced fibrosis, steatohepatitis (with or without fibrosis) or carcinoma. However, it is potentially reversible, even in the most severe cases, which reinforces the urgent need to develop reliable methods for detection and evaluation, including throughout treatment. Current methods for diagnosis and measurement of liver fat are still flawed: ultrasound is not able to perform quantification; CT uses ionizing radiation; biopsy, considered the gold standard, is accurate but invasive and focal. Magnetic resonance imaging (MRI) and spectroscopy (MRS) are completely non-invasive alternatives capable of providing diagnosis and quantification of infiltrated fat in the liver. However, studies in the literature frequently employ pulse sequences especially developed for this purpose, with extremely elaborate post-processing methods, which are not compatible with the current state of the art of typical clinical scanners or even with the level of experience and knowledge of technical staff working in radiology clinics. Thus, the main goal of this study was to evaluate the potential of MRI as a candidate for diagnosing and quantifying fat liver in clinical settings, using conventional pulse sequences, acquisition and post-processing protocol, compatible with those performed in clinical examinations in both simplicity and total acquisition time. We investigated different approaches of MRI and MRS using liver biopsy as reference standard. We evaluated patients with type II diabetes, which have a high prevalence of non-alcoholic fat liver disease, and great variability in the percentage of fat. Correlation, accuracy, sensitivity and specificity measurements of each of the approaches used were performed. All evaluated methods highly correlated (> 87%) with the data obtained from invasive measurement, which shows that the values obtained using MRI are consistent with that observed for liver biopsy. Although the processing methods used are not as complex as would be required if an absolute quantification was desired, our analyzes showed high accuracy, sensitivity and specificity of MRI in the evaluation of steatosis. In conclusion, MRI is an excellent candidate to assess liver fat fraction in a non-invasive way, even when considering the limitations imposed by conventional clinical setting. This suggests that these new methods may begin to migrate to clinical environments without relying on complex sequences and exotic post-processing techniques that are described in the current literature.