Introdução: Em relação ao fígado, a esteatose é a consequência mais comum do consumo abusivo do etanol e predispõe à doença hepática mais grave. Os mecanismos da doença hepática alcoólica não são plenamente conhecidos e as terapias são escassas. Os objetivos desta tese foram: 1) averiguar os efeitos do etanol no fígado, utilizando o zebrafish como modelo experimental; 2) avaliar o tratamento com o Lactobacillus rhamnosus GG (LGG) na esteatose hepática; 3) observar os efeitos do etanol e do tratamento com o LGG no comportamento do zebrafish. Métodos: Foram realizados três experimentos utilizando peixes zebrafish, adultos, wildtype. O primeiro experimento foi formado por dois grupos, Controle (C) e Etanol (E), com 52 animais em cada um. O grupo E foi exposto a 0,5% de etanol por quatro semanas. Foram conduzidas análises histológicas e moleculares dos genes il-1b, tnf-α, il-10, sirt1, adiponectina e adipor2 nos fígados dos animais. No 2°experimento foram avaliados quatro grupos: Controle (C), Probiótico (P), Etanol (E) e Probiótico + Etanol (P + E), com 220 animais respectivamente. Durante quatro semanas os grupos P + E e P foram alimentados com ração com o probiótico LGG e os grupos E e C com ração sem probiótico. Foram realizadas análises histológicas e morfométricas no tecido hepático, quantificações de lipídeos séricos e hepáticos. No 3° experimento, os grupos C, E, P e P+E foram formados (n=15 animais por grupo) e, após duas semanas, o comportamento dos animais foi analisado no teste open-tank com o programa ANYmaze ®. Resultados: No 1° experimento os animais do grupo E apresentaram intensa esteatose hepática, aumento de glicogênio plasmático associado às gotículas lipídicas, alterações no retículo endoplasmático rugoso e degeneração de canalículos biliares. Houve acentuação na expressão hepática de il-1b, tnf-α, sirt1 e do adipor2, indicando que o etanol desencadeou resposta inflamatória e de proteção hepática. No 2° experimento, o grupo E apresentou intensa esteatose após quatro semanas, ao contrário do grupo P + E. A morfometria celular mostrou um aumento de 14,8 vezes no tamanho dos hepatócitos do grupo E (4° semana) quando comparado com C (p <0,0001). Os triglicerídeos séricos diminuíram no grupo P + E em comparação com C, P (p <0,001) e E (p = 0,004). O colesterol sérico do grupo P diminuiu comparado aos grupos C e E na segunda semana (p = 0,002 e p = 0,007) e do grupo P + E diminuiu comparado aos grupos E e C (p<0,0001), na quarta semana. As concentrações de triglicerídeos hepáticos reduziram no grupo P + E na quarta semana em comparação com E (p = 0,006). No 3° experimento, os animais expostos ao etanol apresentaram menor ansiedade em relação ao novo ambiente, evidenciada pela maior exploração da área superior do aquário. O efeito desibinidor do etanol não foi significativamente atenuado pelo tratamento com o LGG. Conclusões: Os resultados do primeiro estudo indicaram que o etanol desencadeia uma série de eventos celulares e moleculares e que a inflamação desempenha papel significativo na esteatose hepática. No segundo, foi demonstrado que o tratamento com LGG diminuiu os níveis séricos de triglicerídeos e de colesterol, atenuando a esteatose hepática. O terceiro estudo mostrou que o etanol teve efeito significativo no comportamento do zebrafish, que não foi modificado pelo LGG. / Introduction: Regarding to the liver, hepatic steatosis is the most common consequence of abusive alcohol consumption and predisposes to more severe liver disease. The mechanisms of alcoholic liver disease are not fully known and therapies are scarce. The objectives of this thesis were: 1) to verify the effects of ethanol in the liver using the zebrafish as an experimental model; 2) to evaluate a treatment with the probiotic Lactobacillus rhamnosus GG (LGG) in hepatic steatosis; 3) to observe the effects of ethanol and treatment with LGG in zebrafish behavior. Methods: Three experiments were performed using zebrafish, adult, wildtype. For the 1st trial, two groups were formed: Control (C) and Ethanol (E), with 52 animals in each group. E group was exposed to 0.5% ethanol during four weeks. Histological and molecular analysis of genes il-1b, tnf-α, il-10, sirt1, adiponectin, and adipor2 were conducted in zebrafish livers. For the 2nd trial, four groups were evaluated: Control (C), Probiotic (P), Ethanol (E) and Probiotic + Ethanol (P + E). During four weeks, the P + E and P groups were fed with food supplemented with LGG and E and C groups received food without probiotic. Histological and morphometric analysis in liver tissue, measurements of serum and hepatic lipids were performed. In the 3rd trial, C, E, P and P + E groups were formed and after two weeks, the animals' behavior was analyzed in opentank test with ANYmaze ® program. Results: In the 1st trial, animals in E group developed severe liver steatosis and cell abnormalities were observed: increase of glycogen associated to lipid droplets, alterations in the rough endoplasmic reticulum, degeneration of biliary canaliculi with presence of myelin figures inside. Increased hepatic expression of il-1b, tnf-α, sirt1 and adipor2 possibly indicates that ethanol triggered both inflammatory and hepatic protection responses. In the 2nd trial, E group presented severe steatosis after four weeks, in contrast to the E + P group. Cell morphometry showed a 14.8 fold in hepatocytes size of E (4th week) compared to C group (p <0.0001). Serum triglycerides decreased in the P + E group compared with C, P (p <0.001) and E groups (p = 0.004). Serum cholesterol decreased in P group compared to C and E groups at second week (p = 0.002 and p = 0.007) and in E + P group decreased compared with E and C groups (p<0.0001) at fourth week. Liver triglycerides were reduced in the P + E group at the fourth week compared to E group (p = 0.006). In the 3rd trial, there was an alteration in the behavior of animals exposed to ethanol compared to that nonexposed, an effect not significantly attenuated by treatment with LGG. Conclusions: Results of the first study indicate that ethanol triggers a series of cellular and molecular events and inflammation plays a significant role in hepatic steatosis. Then, it was shown that treatment with LGG decreased serum levels of triglycerides and cholesterol, attenuating hepatic steatosis. The third study showed that the ethanol, but not LGG has a significant effect on zebrafish behavior.

A aterosclerose é um processo inflamatório que se inicia na infância e progride com a idade, sendo o principal processo patológico que culmina nas doenças cardiovasculares. Ácidos graxos ômega 3 (N-3 FA) reduzem triacilgliceróis plasmáticos e inflamação, enquanto fitosteróis possuem ação hipocolesterolêmica. Portanto, o objetivo deste estudo foi de aplicar a combinação dessas duas classes de lipídios bioativos na infância, visando reduzir a aterosclerose na fase adulta. O estudo foi dividido em duas etapas. Inicialmente, o efeito de três ingredientes contendo N-3 FA foi avaliado em termos de perfil lipídico e biomarcadores inflamatórios. Camundongos adultos LDLr Knockout receberam uma dieta hiperlipídica e foram simultaneamente suplementados com água (CON), óleo de algas (ALG), óleo de peixe (FIS) e óleo de Echium (ECH) através de gavagem durante 4 semanas. Os animais suplementados com óleo de Echium apresentaram os maiores índices de redução de triacilgliceróis e VLDL, além de inibição da esteatose causada pelo dieta hiperlipídica. Entretanto, diferente dos óleos marinhos, tais efeitos não envolveram ativação de fatores de transcrição envolvidos no metabolismo lipídico, como PPAR&#945; e LXR&#945; hepáticos. Na segunda etapa deste estudo, camundongos Knockout LDLr recém-desmamados foram suplementados durante 2 meses com emulsões preparadas com óleo de soja (CON), óleo de de Echium (ECH), óleo de alga (ALG), fitosteróis isolados (PHY), óleo de alga + fitosteróis (ALG+PHY) e óleo de Echium + fitosteróis (ECH+PHY). A seguir, dislipidemia e estresse oxidativo foram induzidos através de uma dieta hiperlipídica por mais 2 meses. Todos os animais apresentaram estrias gordurosas na aorta, sendo que a área de lesão foi maior naqueles suplementados com fitosteróis isoladamente (PHY). Entretanto, esse efeito negativo foi totalmente revertido pela co-suplementação com N-3 FA. Observou-se que os fitosteróis isolados agiram como agonistas de LXR&#945;, e que a reversão proporcionada pelos N-3 FA envolveu aumento da expressão do fator de transcrição PPAR&#945; e redução do aumento de LXR&#945;. Além disso, o óleo de Echium reduziu o estresse oxidativo no fígado através de mecanismos associados à modulação da atividade e expressão de enzimas antioxidantes. Nossos resultados sugerem que a melhor alternativa no desenvolvimento de alimentos funcionais para crianças, visando prevenção de aterosclerose na fase adulta, foi conferida pelos N-3 FA provenientes do óleo de Echium. / Atherosclerosis is an inflammatory process that begins in childhood and progresses with age, being the main pathological process that culminates in cardiovascular disease. Omega 3 fatty acids (n-3 FA) reduces triacylglycerol (TG) and inflammation, while phytosterols present hypocholesterolemic action. Therefore, the aim of this study was to apply the combination of these two classes of bioactive lipids in childhood to reduce atherosclerosis in adulthood. The study was divided into two steps. Initially, the effect of three ingredients containing n-3 FA was evaluated in terms of lipid and inflammatory biomarkers. LDLr knockout adult mice received a high-fat diet and were simultaneously supplemented with water (CON), algae oil (ALG), fish oil (FIS) and Echium oil (ECH) by gavage for 4 weeks. The animals supplemented with Echium oil presented higher reduction of TG and VLDL. Besides, Echium oil inhibited hepatic steatosis caused by high-fat diet. However, unlike of marine oils, this hypotriglyceridemic effect did not involve activation of transcription factors associated to lipid metabolism, such as PPAR&#945; and LXR&#945;. At the second step of this study, weaning LDLr knockout mice were supplemented with emulsions prepared with soybean oil (CON), Echium oil (ECH), algae oil (ALG), isolated phytosterols (PHY), algae oil + phytosterols (ALG + PHY) and Echium oil + phytosterols (PHY + ECH) for 2 months. Thereafter, dyslipidemia and oxidative stress were induced by a high fat diet for 2 months more. All animals showed fatty streaks in the aorta artery. The lesion area was greatest in mice supplemented with isolated phytosterol (PHY). However, this negative effect was completely reversed by co-supplementation with n-3 FA. It was observed that isolated phytosterols acted as LXR&#945; agonists, and that the reversal provided by the N-3 FA involved the increase of PPAR&#945; and reduction of LXR&#945; expression. Furthermore, the Echium oil reduced oxidative stress in liver through mechanisms associated with modulation of antioxidant enzymes activity and expression. Our results suggest that the best alternative to develop functional foods for children, aimed at preventing atherosclerosis in adulthood, was conferred by the N-3 FA from Echium oil.

Orientador: Licio Augusto Velloso / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-12T13:12:05Z (GMT). No. of bitstreams: 1 Cintra_DennysEsper_D.pdf: 2036070 bytes, checksum: 1c0ff9462c147443a4261b0699b9128d (MD5) Previous issue date: 2008 / Resumo: A obesidade se manifesta de forma pandêmica, acometendo milhões de pessoas, principalmente nos países ocidentais e industrializados. Além dos inúmeros aspectos comportamentais e sociais, o desenvolvimento dessa doença contribui consideravelmente para o aumento da morbidade e mortalidade em decorrência de sua freqüente associação com outras doenças que compõem a síndrome metabólica, tais como, diabetes mellitus, hipertensão arterial, dislipidemia, ovários policísticos, esteatose hepática, entre outras. Os distúrbios no metabolismo de ácidos graxos frequentemente relacionados à obesidade contribuem para a disfunção de múltiplos órgãos e sistemas. No fígado, o simples acúmulo de gordura no parênquima (esteatose hepática) pode ser um estado transitório e benigno, facilmente reversível. Entretanto, com a perpetuação do quadro, e dependendo de algumas características genéticas ainda pouco conhecidas, ativa-se uma resposta inflamatória que desempenhará papel central na progressão da esteatose para esteato-hepatite, fibrose e cirrose, sendo esta um estágio final da doença hepática. Durante a instalação da inflamação hepática, uma série de citocinas pró-inflamatórias são expressas e participam da indução da disfunção orgânica. Entretanto, alguns estudos recentes revelam que a interleucina-10 (IL-10), uma citocina antiinflamatória, também é produzida no fígado e que sua presença nesse contexto ameniza a progressão para graus avançados de lesão hepática. O objetivo desse trabalho foi investigar como a IL- 10 endógena modula alguns parâmetros inflamatórios e metabólicos no fígado de um modelo animal de obesidade, resistência à insulina e esteato-hepatite induzidos por dieta. Para tal, a IL-10 foi inibida in vivo por técnicas de inativação com anticorpo específico e oligonucleotídeos de cDNA modificado complementares ao RNAm dessa proteína, impedindo sua tradução. A inibição da IL-10 em animais que consumiram dieta rica em gordura acentuou a disfunção hepática, inibindo a atividade de importantes proteínas como as do receptor de insulina e seus substratos (IR, IRS-1 e IRS-2), fomentando o processo inflamatório local e ativando vias pró-apoptóticas. A partir desses resultados, conclui-se que a IL-10 endógena atua como um fator protetor, controlando vias inflamatórias durante a progressão da esteatose para esteato-hepatite não alcoólica. / Abstract: Obesity has grown as an epidemiological phenomenon that threatens millions of people worldwide, and particularly those living in western, developed countries. Besides its multiple behavioral and social problems, obesity contributes considerably to increase morbidity and mortality due to its common association with diseases that compose the metabolic syndrome, such as diabetes mellitus, hypertension, dyslipidemia, polycystic ovaries, hepatic steatosis, among others. The abnormalities in the metabolism of fatty acids that frequently occur in obesity, contribute to the dysfunction of a number of organs and systems. In the liver, the simple accumulation of fat in the parenchyma cells leads to steatosis which is somewhat benign and reversible. However, as far as the condition is maintained, and depending on some yet to be known genetic factors, an inflammatory response can be installed leading to steatohepatitis, fibrosis and cirrhosis, a terminal liver disease. During the installation of steatohepatitis, a number of proinflammatory cytokines are expressed, contributing to the progression of the liver damage. However, some recent studies have shown that interleukin-10 (IL- 10), an anti-inflammatory cytokine, is produced in the liver and plays a role in the negative modulation of the inflammatory response. The objective of the present study was to evaluate the roles of IL-10 as an endogenous factor controlling inflammatory and metabolic parameters in diet induced hepatic steatosis. IL-10 was inhibited in vivo by two distinct methods, a neutralizing antibody and an antisense oligonucleotide. The inhibition of IL-10 in diet induced steatohepatitis increased proinflammatory cytokine expression and worsened a number of metabolic parameters, including insulin signal transduction. Thus, IL-10 is an endogenous factor that modulates inflammatory response in diet-induced hepatic disease. / Doutorado / Ciencias Basicas / Doutor em Clínica Médica

Motivées par l'observation mondiale de l'augmentation de la morbidité et de la mortalité associées à des pathologies liées à l'obésité, dont la stéatose, les études pré-cliniques et cliniques s'intéressent à la recherche de nouveaux biomarqueurs pour le diagnostic de la stéatose. Actuellement, la stéatose est diagnostiquée et gradée par des analyses histologiques à partir d'une biopsie du foie. Dans l'intérêt du patient, et afin de permettre un suivi de la stéatose lors d'un régime ou d'un traitement, il est apparu important de se tourner vers des modalités de diagnostic moins invasives. Dans ce cadre, la spectroscopie par résonance magnétique (SRM), non-invasive et non-ionisante, est une méthode de choix pour le diagnostic de la stéatose par la mesure de la fraction lipidique hépatique. De plus, à partir des informations observables sur un spectre de SRM acquis au niveau hépatique, il est possible d'envisager une quantification de la composition en acides gras (AG) des lipides hépatiques, potentiel biomarqueur pour le suivi d'une stéatose. Les travaux de cette thèse ont été réalisés à partir d'objets-tests, et dans le cadre d'études pré-cliniques (4,7 T) et cliniques (3,0 T). Une étude du protocole d'acquisition de spectres de SRM pour la quantification de la composition en AG des lipides a été réalisée, avec notamment un questionnement quant à la nécessité de l'utilisation d'un module de suppression du signal de l'eau. Un état de l'art des algorithmes de quantification de la composition en AG des lipides a été effectué, et des tests de validations de ces algorithmes ont été réalisés afin de déterminer le plus approprié à la problématique hépatique, dans nos conditions expérimentales. Enfin, toujours dans l'objectif de déterminer des nouveaux biomarqueurs de la stéatose, une méthode de mesure par SRM in vivo du T1 de l'eau et de la résonance majeure des lipides hépatiques (LOREEDE pour LOngitudinal RElaxation time Evaluation from Dynamic Equilibrium) a été développée, et validée au cours d'une étude préliminaire sur des objets-tests et in vivo sur modèles murins. / In recent years, there has been an unprecedented increase in the morbidity and mortality associated with diseases such as the steatosis, linked to obesity. In this context, pre-clinical and clinical studies are of interest in the search for new biomarkers allowing the diagnosis of steatosis. Currently, steatosis is diagnosed and graded by histological analyzes from a liver biopsy. On the other hand, it is advantageous to use non-invasive diagnostic modalities, especially in longitudinal studies. In this context, magnetic resonance spectroscopy (MRS), as a non-invasive and non-ionizing approach, is an attractive alternative method for the diagnosis of steatosis by measuring the hepatic fat fraction. Moreover, from the MRS spectrum acquired in the liver, it is possible to quantify the fatty acids (FA) composition of the hepatic lipids, which could be a potential biomarker for the follow-up of steatosis. The work of this thesis has been performed in vitro and in vivo, in the context of pre-clinical (4.7 T) and clinical (3.0 T) studies. An investigation of the optimal MRS acquisition protocol for the quantification of FA was carried out, with particular attention to the role of the water signal suppression module. Different quantification algorithms of the lipid composition were studied and validation of these algorithms was carried out in vitro and in vivo. Finally, still with the objective of determining new biomarkers of steatosis, a method (LOREEDE: LOngitudinal RElaxation time Evaluation from Dynamic Equilibrium) for the measurement in vivo of the T1 of the water resonance and the major lipid resonance, by MRS, was developped and validated in a preliminary study.

La protéine core du virus de l’hépatite C (VHC) serait responsable des principaux effets pathogènes du VHC, dont le développement de fibrose, stéatose, cirrhose et carcinome hépatocellulaire. Un cadre de lecture alternatif existe dans le gène de core, permettant la synthèse d’une autre protéine appelée ARFP (pour alternatate reading frame protein) ou protéine F (pour frameshift), dont le rôle reste encore mal compris. La présence de la protéine F lors de l’étude des fonctions biologiques de core ne pouvant être exclue, il est possible que certains rôles attribués à core reflètent en réalité l’activité de la protéine F. Afin de déterminer les fonctions biologiques de la protéine F dans les hépatocytes et son influence dans la pathogenèse associée au VHC, nous avons généré des lignées transgéniques de poissons zébrés (Danio rerio) dans lesquelles l’expression de deux versions de la protéine F (AF11opti et AUG26opti) a été ciblée au foie par l’utilisation du promoteur de la liver fatty acid binding protein (L-FABP). Le phénotype des poissons transgéniques de génération F2 a été analysé au niveau morphologique, histologique et microscopique afin de rechercher des signes de pathologie hépatique. Nos résultats ont démontré l’implication de la protéine F dans le développement de stéatose hépatique chez les deux lignées transgéniques, mais aucun signe de fibrose ou d’oncogenèse n’a été détecté. L’identification des mécanismes cellulaires et moléculaires responsables de l’accumulation lipidique induite par la protéine F pourrait permettre de mieux comprendre son rôle dans la pathogenèse du VHC, et mener au développement de nouvelles stratégies antivirales. / Hepatitis C virus (HCV) core protein is thought to be responsible for the major pathogenic effects of HCV, including the development of fibrosis, steatosis, cirrhosis, and hepatocellular carcinoma. An alternate translational open reading frame exists in the core gene that allows the synthesis of another protein called ARFP (alternate reading frame protein) or F protein (frameshift), the role of which remains poorly understood. Since we cannot exclude the presence of F protein in most studies of core biological functions, it is possible that the roles attributed to core reflect the activity of ARFP. To determine the biological functions of F protein in hepatocytes and their influence on HCV-associated pathogenesis, we generated transgenic lines of zebrafish (Danio rerio) in which the liver fatty acid binding protein (L-FABP) promoter was used to direct liver-specific expression of two forms of ARFP (AF11opti and AUG26opti). The phenotype of F2 transgenic zebrafish was analyzed for morphological, histological and microscopic signs of liver-associated pathology. Our results demonstrated the implication of the HCV F protein in the development of hepatic steatosis in transgenic zebrafish liver but not fibrosis or oncogenesis. Identification of the cellular and molecular mechanisms underlying F protein-induced lipid accumulation will lead to a better understanding of the role of ARFP in HCV-associated pathology, which could lead to the development of novel antiviral strategies.

Introdução: Os efeitos metabólicos do uso combinado dos triglicerídeos de cadeia média (TCM) e do óleo de peixe (OP) na esteatose hepática ainda não estão totalmente esclarecidos. Objetivo: O presente estudo teve o objetivo de verificar os efeitos da combinação dos TCMs e OP na esteatose hepática e estresse oxidativo induzidos pela dieta hiperlipídica (HL+) termolizada em ratos. Material e Métodos: Foram utilizados no total 50 ratos machos da linhagem Wistar. O grupo Controle (n=10) recebeu a dieta controle. Os grupos HL+ receberam a dieta contendo 50% de gordura animal (GA) termolizada e 50% de ração. A adaptação às dietas HL+ foi realizada durante 5 dias. Os grupos HL+GA, HL+TCM, HL+OP e HL+TCM/OP (n=10) receberam a dieta HL+ com 50% de lipídios (gordura animal termolizada) durante 30 dias. Após este período, os grupos HL+TCM, HL+OP e HL+OP/TCM receberam as dietas HL+ adicionadas de óleo de TCM (OTCM), OP e OTCM + OP, respectivamente, durante 20 dias. As análises realizadas foram a gordura hepática total, frações lipídicas hepáticas e séricas, glicemia, vitamina E e retinol séricos, glutationa reduzida (GSH) e malondialdeído (MDA) sérico e hepático e aminotransferases séricas. Resultados: Os grupos HL+ apresentaram acúmulo significativo de gordura total e triglicerídeos hepáticos, exceto o HL+OP. Apenas o grupo HL+TCM não apresentou acúmulo significativo de colesterol total hepático (CT). Este mesmo grupo apresentou valores maiores de CT e HDLcol séricos e menor razão triglicerídeos/HDLcol. Os valores séricos de aminotransferases foram significativamente maiores nos grupos que receberam os OTCM e/ou OP. A peroxidação lipídica (LPO) hepática foi maior foi nos grupos HL+, exceto o HL+TCM. Apenas o grupo HL+GA apresentou maior LPO sérica. Verificou-se que a GSH foi maior nos grupos HL+GA, HL+TCM e HL+OP/TCM, a vitamina E sérica foi menor nos grupos HL+GA, HL+OP e HL+OP/TCM e o retinol sérico foi maior nos grupos HL+GA e HL+TCM. Conclusões: As alterações séricas não refletiram as alterações hepáticas em relação aos lipídios, estresse oxidativo e antioxidantes. O uso do óleo de TCM e óleo de peixe em associação na dieta HL+ resultou em efeito negativo devido ao maior acúmulo de gordura hepática tanto na forma de triglicerídeos quanto de colesterol, maior peroxidação lipídica hepática e menor vitamina E sérica. / Introduction: The metabolic effects of combined use of medium chain triglycerides (MCT) and fish oil (FO) on non alcoholic hepatic steatosis are not fully understood. Objective: The aim of this study was to investigate the effects of the combination of MCT and FO on hepatic steatosis and oxidative stress induced by high fat (HF+) thermolyzed diet in rats. Methodology: Fifty wistar male rats were studied. The Control group (n = 10) received the standard diet. The HF+ groups received diet with 50% of thermolyzed animal fat (AF) and 50% of ration. Five days were dedicated for adaptation to high-fat diets. The groups HF+AF, HF+MCT, HF+FO and HF+MCT/FO (n = 10) received HF+ diet with 50% thermolyzed fat during 30 days. After this period, the groups HF+MCT, HF+FO and HF+MCT/FO received HF+ diets with MCT oil (MCTO), FO and MCTO + OP, respectively, during 20 days. Analysis of total liver fat, liver and serum lipid fractions, serum glucose, vitamin E and retinol, serum and liver reduced glutathione (GSH) and malondialdehyde (MDA), and serum aminotransferases (AST and ALT) were performed. Results: The groups HF+ showed higher total fat and triglycerides, except HF+FO. Only HF+MCT group didn´t have higher liver total colesterol (TC). This same group had higher serum TC and HDLcol and lower triglycerides/HDLcol ratio. The groups fed with MCTO and/or FO had higher serum aminotransferase. Liver lipid peroxidation (LPO) was higher in HF+ groups, except HF+MCT. Serum LPO was higher in HF+AF. The hepatic GSH was higher in the groups HF+AF, HF+MCT and HF+MCT/FO, serum vitamin E was lower in groups HF+AF, HF+FO and HF+MCT/FO, and serum retinol was higher in groups HF+AF and HF+MCT. Conclusions: Lipids, oxidative stress and antioxidant serum and liver alterations didnt correspond. The association of MCTO with FO in HF+ diet resulted in a negative effect when it concerns liver fat, triglyceride and cholesterol accumulation, higher liver lipid peroxidation and lower serum vitamin E.

CTRP3 is a secreted plasma protein of the C1q family that helps regulate hepatic gluconeogenesis and is downregulated in a diet-induced obese state. However, the role of CTRP3 in regulating lipid metabolism has not been established. Here, we used a transgenic mouse model to address the potential function of CTRP3 in ameliorating high-fat diet-induced metabolic stress. Both transgenic and wild-type mice fed a high-fat diet showed similar body weight gain, food intake, and energy expenditure. Despite similar adiposity to wild-type mice upon diet-induced obesity (DIO), CTRP3 transgenic mice were strikingly resistant to the development of hepatic steatosis, had reduced serum TNF-α levels, and demonstrated a modest improvement in systemic insulin sensitivity. Additionally, reduced hepatic triglyceride levels were due to decreased expression of enzymes (GPAT, AGPAT, and DGAT) involved in triglyceride synthesis. Importantly, short-term daily administration of recombinant CTRP3 to DIO mice for 5 days was sufficient to improve the fatty liver phenotype, evident as reduced hepatic triglyceride content and expression of triglyceride synthesis genes. Consistent with a direct effect on liver cells, recombinant CTRP3 treatment reduced fatty acid synthesis and neutral lipid accumulation in cultured rat H4IIE hepatocytes. Together, these results establish a novel role for CTRP3 hormone in regulating hepatic lipid metabolism and highlight its protective function and therapeutic potential in attenuating hepatic steatosis.

The central nervous system (CNS) melanocortin signaling pathway plays a critical role in the regulation of metabolism. However, the regulatory effects of CNS melanocortin signaling on hepatic lipid metabolism and fatty liver disease have not been well established. Although the activity of the CNS melanocortin system is regulated by metabolic signals, the mechanism for this regulation is not fully understood. Variants of the FTO (fat mass and obesity-associated) gene are associated with obesity and FTO is expressed in the hypothalamic neurons including proopiomelanocortin (POMC) neurons. Therefore, it is hypothesized that hypothalamic FTO plays a role in the regulation of metabolism by mediating the effect of metabolic signals on hypothalamic melanocortinergic neurons, and that impairments in this regulation may cause metabolic impairments including obesity and fatty liver disease. Intracerebroventricular (i.c.v.) treatment with SHU9119, a melanocortin antagonist, increased hepatic lipid accumulation and the expression of genes encoding lipogenic enzymes in lean mice. Conversely, i.c.v. treatment with MTII, a melanocortin agonist, reduced the expression of hepatic lipogenic genes in association with reduction in body weight in ob/ob mice, a mouse model of fatty liver disease. Immunohistochemical analysis demonstrated that Fto is co-expressed in both POMC and agouti-related protein (AgRP) neurons in the mouse hypothalamus. Fto mRNA and protein expression was reduced by fasting and increased by glucose treatment in nutritionally important hypothalamic nuclei. Fasting-induced reduction in hypothalamic Fto expression was observed in both lean wild-type and obese ob/ob mice, while the stimulatory effect of glucose on hypothalamic Fto expression was absent in ob/ob mice. These findings support the hypothesis that central melanocortin signaling regulates hepatic lipid metabolism in part by regulating de novo lipogenesis. Impairments in the central melanocortin signaling lead to the development of hepatic steatosis, while enhanced melanocortin signaling may be beneficial in reversing abnormal hepatic lipid metabolism in fatty liver disease (Poritsanos et al., 2008). These findings also support the hypothesis that Fto is expressed in the hypothalamic melanocortinergic neurons and is regulated by metabolic signals involving changes in CNS glucose availability and/or glucose action. Impairments in this regulation may cause metabolic impairments including obesity and fatty liver disease.

The central nervous system (CNS) melanocortin signaling pathway plays a critical role in the regulation of metabolism. However, the regulatory effects of CNS melanocortin signaling on hepatic lipid metabolism and fatty liver disease have not been well established. Although the activity of the CNS melanocortin system is regulated by metabolic signals, the mechanism for this regulation is not fully understood. Variants of the FTO (fat mass and obesity-associated) gene are associated with obesity and FTO is expressed in the hypothalamic neurons including proopiomelanocortin (POMC) neurons. Therefore, it is hypothesized that hypothalamic FTO plays a role in the regulation of metabolism by mediating the effect of metabolic signals on hypothalamic melanocortinergic neurons, and that impairments in this regulation may cause metabolic impairments including obesity and fatty liver disease. Intracerebroventricular (i.c.v.) treatment with SHU9119, a melanocortin antagonist, increased hepatic lipid accumulation and the expression of genes encoding lipogenic enzymes in lean mice. Conversely, i.c.v. treatment with MTII, a melanocortin agonist, reduced the expression of hepatic lipogenic genes in association with reduction in body weight in ob/ob mice, a mouse model of fatty liver disease. Immunohistochemical analysis demonstrated that Fto is co-expressed in both POMC and agouti-related protein (AgRP) neurons in the mouse hypothalamus. Fto mRNA and protein expression was reduced by fasting and increased by glucose treatment in nutritionally important hypothalamic nuclei. Fasting-induced reduction in hypothalamic Fto expression was observed in both lean wild-type and obese ob/ob mice, while the stimulatory effect of glucose on hypothalamic Fto expression was absent in ob/ob mice. These findings support the hypothesis that central melanocortin signaling regulates hepatic lipid metabolism in part by regulating de novo lipogenesis. Impairments in the central melanocortin signaling lead to the development of hepatic steatosis, while enhanced melanocortin signaling may be beneficial in reversing abnormal hepatic lipid metabolism in fatty liver disease (Poritsanos et al., 2008). These findings also support the hypothesis that Fto is expressed in the hypothalamic melanocortinergic neurons and is regulated by metabolic signals involving changes in CNS glucose availability and/or glucose action. Impairments in this regulation may cause metabolic impairments including obesity and fatty liver disease.

La protéine core du virus de l’hépatite C (VHC) serait responsable des principaux effets pathogènes du VHC, dont le développement de fibrose, stéatose, cirrhose et carcinome hépatocellulaire. Un cadre de lecture alternatif existe dans le gène de core, permettant la synthèse d’une autre protéine appelée ARFP (pour alternatate reading frame protein) ou protéine F (pour frameshift), dont le rôle reste encore mal compris. La présence de la protéine F lors de l’étude des fonctions biologiques de core ne pouvant être exclue, il est possible que certains rôles attribués à core reflètent en réalité l’activité de la protéine F. Afin de déterminer les fonctions biologiques de la protéine F dans les hépatocytes et son influence dans la pathogenèse associée au VHC, nous avons généré des lignées transgéniques de poissons zébrés (Danio rerio) dans lesquelles l’expression de deux versions de la protéine F (AF11opti et AUG26opti) a été ciblée au foie par l’utilisation du promoteur de la liver fatty acid binding protein (L-FABP). Le phénotype des poissons transgéniques de génération F2 a été analysé au niveau morphologique, histologique et microscopique afin de rechercher des signes de pathologie hépatique. Nos résultats ont démontré l’implication de la protéine F dans le développement de stéatose hépatique chez les deux lignées transgéniques, mais aucun signe de fibrose ou d’oncogenèse n’a été détecté. L’identification des mécanismes cellulaires et moléculaires responsables de l’accumulation lipidique induite par la protéine F pourrait permettre de mieux comprendre son rôle dans la pathogenèse du VHC, et mener au développement de nouvelles stratégies antivirales. / Hepatitis C virus (HCV) core protein is thought to be responsible for the major pathogenic effects of HCV, including the development of fibrosis, steatosis, cirrhosis, and hepatocellular carcinoma. An alternate translational open reading frame exists in the core gene that allows the synthesis of another protein called ARFP (alternate reading frame protein) or F protein (frameshift), the role of which remains poorly understood. Since we cannot exclude the presence of F protein in most studies of core biological functions, it is possible that the roles attributed to core reflect the activity of ARFP. To determine the biological functions of F protein in hepatocytes and their influence on HCV-associated pathogenesis, we generated transgenic lines of zebrafish (Danio rerio) in which the liver fatty acid binding protein (L-FABP) promoter was used to direct liver-specific expression of two forms of ARFP (AF11opti and AUG26opti). The phenotype of F2 transgenic zebrafish was analyzed for morphological, histological and microscopic signs of liver-associated pathology. Our results demonstrated the implication of the HCV F protein in the development of hepatic steatosis in transgenic zebrafish liver but not fibrosis or oncogenesis. Identification of the cellular and molecular mechanisms underlying F protein-induced lipid accumulation will lead to a better understanding of the role of ARFP in HCV-associated pathology, which could lead to the development of novel antiviral strategies.