Introdução. O amaranto é um pseudocereal de alto valor nutritivo, além de apresentar propriedade de redução do colesterol plasmático. O conteúdo lipídico de seus grãos é superior ao dos cereais comuns, com elevado teor de ácidos graxos insaturados, além de apresentar quantidade significante de esqualeno, um dos possíveis compostos bioativos responsáveis pela redução do colesterol. Objetivo. Verificar o efeito do óleo de amaranto e do esqualeno no metabolismo lipídico de hamsters alimentados com gordura saturada e colesterol. Metodologia. O óleo de amaranto foi extraído por solvente orgânico (n-hexano) e analisado nos seus conteúdos de esqualeno. O potencial efeito hipocolesterolemizante deste óleo foi avaliado mediante um ensaio biológico, em que foram utilizados 40 hamsters recémdesmamados. Os animais foram divididos em 4 grupos de 10, diferenciados pelas dietas: controle [dieta normal com 20% de óleo de milho] (C), hipercolesterolêmica [dieta com 12% de gordura de côco, 8% de óleo de milho e 0,1% de colesterol] (H), óleo de amaranto [idêntica à (H) com óleo de amaranto substituindo o de milho] (A) e esqualeno [idêntica à (H) + esqualeno na proporção encontrada no óleo de amaranto] (E), formuladas segundo as recomendações da NRC (1995) e AIN-93. Após 28 dias de experimento, os animais tiveram o sangue coletado por punção cardíaca, sob anestesia, sendo determinados o colesterol total, triglicérides, HDL-c e colesterol não-HDL plasmáticos. Após sacrifício, os fígados dos animais foram coletados para a realização da análise histológica e do teor de colesterol. Também foram determinados os teores de colesterol e ácidos biliares das fezes dos animais. Resultados. Não houve diferença estatisticamente significante no perfil lipídico e excreção fecal de colesterol dos animais dos grupos hipercolesterolêmico, óleo de amaranto e esqualeno. A excreção fecal de ácidos biliares foi maior nos animais dos grupos óleo de amaranto e esqualeno em comparação com os grupos controle e hipercolesterolêmico. O teor de colesterol hepático dos animais do grupo esqualeno foi maior em relação aos outros grupos, embora tenha se diferenciado estatisticamente apenas do grupo controle. Em relação à análise histológica hepática, os maiores graus de esteatose e inflamação parenquimatosa foram os dos grupos óleo de amaranto e esqualeno. Conclusões. O óleo de amaranto e o seu componente esqualeno não apresentaram efeito hipocolesterolemizante e promoveram um aumento da excreção de ácidos biliares em hamsters alimentados com dieta contendo elevadas quantidades de gordura saturada e colesterol. / Introduction: Amaranth is a pseudo cereal of superior nutritional value, besides its property of reducing serum cholesterol. The lipid content of the grains is higher than common cereals, with high content of unsaturated fatty acids. Amaranth also presents significant amounts of squalene, a possible bioactive compound responsible for lowering cholesterol. Objective: To investigate the effect of amaranth oil and squalene on lipid metabolism in hamsters fed with saturated fat and cholesterol. Methodology: The amaranth oil was extracted by organic solvent (n-hexane) and its content of squalene was determined. The potential hypocholesterolemic effect of this oil was evaluated by a bioassay, which employed 40 weanling hamsters. The animals were divided into four groups of 10, differentiated by the diets: control [normal diet with 20% corn oil] (C), hypercholesterolemic [diet with 12% fat coconut, 8% corn oil, and 0.1% cholesterol] (H) amaranth oil [identical to (H) with amaranth oil replacing corn oil] (A) and squalene [identical to (H) + squalene in the proportion found in the amaranth oil] (E). They were all formulated according to the recommendations of NRC (1995) and AIN-93. After 28 days, the animals had blood collected by cardiac puncture, under anesthesia, being measured total cholesterol, triglycerides, HDL-C and plasma non-HDL cholesterol. After sacrifice, the livers of animals were collected for histological analysis and determination of cholesterol content. We also determined the levels of cholesterol and bile acids in the feces of animals. Results: There was no statistically significant difference in lipid profile and fecal excretion of cholesterol from animals in the hypercholesterolemic, amaranth oil and squalene groups. Fecal excretion of bile acids was higher in animals in groups of amaranth oil and squalene as compared with the control group and hypercholesterolemic group. The cholesterol content in liver of the animals from squalene group was higher compared to other groups, although this difference was not statistically significant except when compared to the control group. The highest grade of steatosis and parenchymal inflammation were found in the groups of amaranth oil and squalene. Conclusions: The amaranth oil and its component squalene had no effect hypocholesterolemic and promoted an increased excretion of bile acids in hamsters fed a diet containing high amounts of saturated fat and cholesterol.

The incidences of obesity and type 2 diabetes and their complications are increasing globally. The presence of elevated circulating free fatty acids has been associated with the initial dysfunction of pancreatic beta cells and microvascular endothelial cells followed later by their demise. The aim of this thesis was to investigate the mechanisms by which demise occurs, and how it may be prevented. Palmitate, a saturated fatty acid, caused cell death in both INS-1 beta cells and HCMec/D3 microvascular cells, whereas the unsaturated fatty acid oleic acid did not cause cell death, and also protected against palmitate-induced toxicity. Etomoxir, the mitochondrial CPT1 inhibitor did not rescue INS-1 or HCMec/D3 cells from palmitate-induced toxicity suggesting that palmitate-induced toxicity does not occur via entry into the mitochondria. Cells were exposed to 2-bromopalmitate, a non-metabolisable fatty acid used to reduce the pool of cytoplasmic CoA, to determine whether palmitate-induced toxicity might be mediated by its ability to be activated. Pre-incubation with 2-bromopalmitate in INS-1 cells significantly prevented palmitate-induced cell death. These data suggest that the activation of palmitate with CoA might mediate cell death. Cell cycle analysis found that neither oleic acid nor palmitate caused an increase or decrease in cell proliferation in both INS-1 and HCMec/D3 cells. The data suggest that the mechanism of oleic acid-induced cytoprotection might not be via a pro-proliferative mechanism. INS-1 cells were imaged using spontaneous Raman microspectroscopy after 24-hour exposure to esterified and non-esterified fatty acids. Uni- and multi-variate analysis and spectral decomposition were carried out using a methodology optimised and validated which is presented in this thesis. The aim was to quantify changes, if any, in lipid disposition: distribution, intensity (as a measure of concentration) and composition after exogenous exposure to these fatty acids. Exposure to 0.125 mM palmitate showed a significant decrease in the percentage of lipid within the cells and a corresponding increase in the intensity of this lipid. This suggests that palmitate, alone, might be shuttled into lipid droplets. This was not observed when the cells were exposed to oleic acid, whereby an increase in the intensity of lipid was observed even though no significant change was observed in the percentage of lipid within the cells. When palmitate and oleic acid were combined, the composition of the lipid droplets changed such that the levels of palmitate decreased and the levels of oleic acid increased. These data suggest that oleic acid does not shuttle palmitate into lipid droplets. These data do not support the hypothesis that oleic acid protects against palmitate-induced cytotoxicity by shuttling palmitate into lipid droplets. The methyl esters of palmitate and oleic acid were employed to determine whether they would affect lipid disposition. No change in lipid distribution or intensity was observed when the cells were exposed to these fatty acids, validating the requirement for the free carboxyl oxygen for the covalent binding to glycerol for the formation of lipid droplets. These data also suggest that INS-1 cells cannot de-esterify esterified fatty acids.

Perfluoroalkyl substances (PFASs) are anthropogenic compounds that have been classed as persistent organic pollutants (POPs) and are found in both commercial and industrial products. PFASs have been detected in different environmental matrices and have been found to bioaccumulate in all trophic levels. The adverse effects that are associated with PFAS exposure include reduced body weight, increased liver weight, hepatocellular hypertrophy, a decrease in serum cholesterol and triglycerides. This project aims to characterize the metabolic changes in lipid metabolism in the liver after exposure to one of the well-studied PFASs, the perfluorooctane sulfonate (PFOS), during the embryo development using the domestic chicken as a model organism. The characterization of the metabolic changes was done by conducting both quantitative lipidomic analysis and semi-quantitative global profiling on extracted lipids from liver homogenates from a former related project looking at fatty acid profiles. The extracted lipids were analyzed using UHPLC/Q-TOF-MS. In the quantitative analysis, the PFOS-treated groups (0.1 ug/g and 1.0 ug/g)exhibited higher lipid concentrations when compared with the solvent control group (5% DMSO) and the untreated group leading to the conclusion that PFOS exposure disrupts the lipid metabolism. When comparing the lipid concentrations between the two PFOS-treated groups (0.1 ug/g and 1.0 ug/g), the majority of the lipids exhibited higher lipid concentrations in the 1.0 ug/g PFOS-treated groups leading to the conclusion that the effect PFOS has on the lipid metabolism is dose dependent. In the global profiling analysis, 63 lipids showed significant differences when comparing the solvent control group with samples either treated with 0.1 ug/g PFOS or 1.0 ug/g PFOS.

Perfluorooctane sulfonate (PFOS) is widely used in industrial products and is potentially dangerous to the aquatic environment due to not being broken down whether by chemical or biological means, having a half-life of more than 41 years and disrupting hormones. Hexabromocyclododecane (HBCD) is the third most used brominated flame retardant and is of environmental concern as it bioaccumulates and magnifies in the food chain and is highly toxic to aquatic organisms. The purpose of this study was to examine the effect of PFOS and HBCD on the embryos of rainbow trout (Onchorhynchus mykiss) by analyzing lipid profiles with UHPLC/Q-TOF-MS. The fish embryos were treated with various concentrations of PFOS and HBCD (0.058-58 μg/l and 0.014-14 μg/l respectively) with DMSO as carrier solvent and then extracted after homogenization with 0.9% NaCl-solution followed by addition of ISTD mixture, methanol, methyl tert-butyl ether (MTBE) and MQ-water. The raw data was processed with MZmine-2.32. 153 lipids were identified with the main lipids consisting of glycerophospholipids and triacylglycerols. A two-tailed t-test was used to study the impact of the chemical exposure on the embryos, where p-values below 0.05 were lipids considered as significant change. The HBCD exposure caused significant change in various triacylglycerols, whereas PFOS exposure caused significant change in triacylglycerols as well as in glycerophospholipids such as PC(O-38:5) and LPC(20:4). The results were in alignment with previous studies.

Made available in DSpace on 2014-06-11T19:31:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-10-29Bitstream added on 2014-06-13T20:40:58Z : No. of bitstreams: 1 silva_vk_dr_jabo.pdf: 1506111 bytes, checksum: 562838af0ec5f22ad837aa2904b5851a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dois experimentos foram conduzidos com o objetivo de avaliar os efeitos da ingestão contínua de pectina. No primeiro experimento, foram avaliados a digestibilidade da ração, a viscosidade e o tempo de trânsito intestinal. Para isso, 240 frangos de corte macho Cobb® foram distribuídos em delineamento inteiramente casualizado (DIC), em 4 tratamentos (0, 1, 3 e 5% de pectina) compostos por 6 repetições de 10 aves por unidade experimental. As análises foram realizadas em duas fases: inicial (14 a 18 dias) e crescimento (27 a 31 dias). Os resultados mostraram que com a ingestão de pectina houve melhora da digestibilidade dos nutrientes na fase inicial dos frangos e piora na fase de crescimento, aumento na viscosidade e no tempo de trânsito intestinal e redução na umidade da excreta. No segundo experimento, foram analisados o desempenho e rendimento de cortes aos 35 e 42 dias de idade, o desenvolvimento semanal das aves e o consumo de água, parâmetros bioquímicos plasmáticos, morfometria do tecido adiposo abdominal, morfometria do fígado e teor de lipídio total hepático e dos músculos peitoral maior e gastrocnêmio. Foram utilizados 720 pintos machos Cobb® distribuidos em DIC, composto por 4 tratamentos (0, 1, 3 e 5% de pectina) e 6 repetições de 30 aves por unidade experimental. Na última semana, o consumo de água aumentou com o aumento do nível de pectina na ração. O consumo de até 1% de pectina na ração mantém o desempenho das aves. Aos 42 dias de idade ocorreu redução nos valores de proteína total plasmática com a ingestão de pectina. Os níveis de 3 e 5% reduziram as concentrações de colesterol total e, o nível de 5% reduziram os níveis de HDL. A ingestão de pectina proporcionou diminuição na concentração de lipídio hepático e menor relação entre peso corporal e gordura abdominal com a ingestão de 5% de pectina aos 42 dias. As concentrações... / Two experiments were conducted to evaluate the effects of continuous pectin intake. In the first experiment evaluated the digestibility of feed, the viscosity and intestinal transit time. For this, 240 male Cobb® broilers were distributed in a randomized design in four treatments (0, 1, 3 and 5% pectin) formed by 6 repetitions of 10 birds each. Analyses were performed in two stages: early (14 to18 days) and growth (27 to 31 days). The results showed that the ingestion of pectin had improved the digestibility of nutrients in the initial phase of chickens and worsens during growth, increase in viscosity and intestinal transit time and reduction in moisture of excreta. The second experiment analysed the performance and yield of the 35 and 42 days old, the weekly development of birds and water consumption, biochemical parameters, morphometry of abdominal adipose tissue, liver morphology and hepatic, pectoralis major and gastrocnemius lipid content. We used 720 male Cobb® chicks distributed in a completely randomized design with 4 treatments (0, 1, 3 and 5% pectin) consisting of six replicates of 30 birds each. In the last week, water consumption increased with increase level of pectin in the diet. The consumption up to 1% pectin keeps the performance of broilers.. At 42 days of age there was a reduction in total plasma protein values with the intake of pectin. The levels of 3 and 5% reduced the levels of total cholesterol and the level of 5% reduced levels of HDL. The intake of pectin resulted in decreased hepatic lipid content and lower ratio of body weight and abdominal fat with intake of 5% pectin and 42 days. The lipid concentration in the pectoralis major and gastrocnemius muscles were not influenced by levels of pectin in the same age

Introdução: Doenças cardiovasculares constituem importante causa de morte em todo mundo e a hipercolesterolemia está diretamente relacionada a este problema de saúde pública. A dieta desempenha papel importante neste processo e alguns alimentos, como o amaranto (Amaranthus cruentus L. BRSAlegria), têm mostrado capacidade de redução do colesterol plasmático. Estudos sugerem que este efeito está relacionado a peptídeos liberados durante a digestão das proteínas, os quais atuam na modulação do metabolismo lipídico. Considerando-se que os efeitos da digestão gastrointestinal e da absorção destes peptídeos são claramente complexos torna-se importante a realização de estudos visando avaliar bioacessibilidade e mecanismos de ação destes peptídeos nos locais alvo do organismo. Objetivo: Analisar a biodisponibilidade de peptídeos em modelos animais após ingestão de isolado proteico de amaranto e relacioná-la com parâmetros ligados ao metabolismo do colesterol. Métodos: O amaranto teve sua proteína isolada. Os peptídeos da proteína do amaranto foram analisados após digestão in vitro. Dois experimentos in vivo foram conduzidos: um de fase aguda e outro de média duração. No primeiro, o isolado proteico de amaranto foi administrado a ratos e os peptídeos no sangue foram monitorados por 2 horas para verificação de fragmentos que resistissem à digestão gastrointestinal. O experimento in vivo 2 consistiu na alimentação de 3 grupos de hamster, um com dieta recomendada pela AIN93 (grupo N) e dois com dietas hipercolesterolêmicas por 21 dias, contendo a proteína de amaranto como única proteína da ração (grupo I), comparada ao controle de caseína (grupo H). Neste experimento foram analisados no plasma: peptídeos, colesterol total e frações; nas fezes: colesterol total e ácidos biliares; no fígado: colesterol, lipídeos totais, ácidos graxos, atividade enzimática da Hmgcr, expressão de Hmgcr, Srebf2, Lxr, Abca1, Abcg8 e Ampk. Resultados e discussão: Foram identificados fragmentos peptídicos provenientes da digestão in vitro do isolado proteico de amaranto, e outras dezenas de sequencias peptídicas em ratos após administração aguda de amaranto foram analisadas. Destaca-se a identificação do peptídeo ALGV, presente em proteína do amaranto de acordo com banco de dados, e similar a fragmentos com ação hipocolesterolemizante. No sangue de hamsters foram encontrados seis peptídeos com 100 por cento de cobertura e similaridade a base de dados de proteínas de amaranto, merecendo investigação sobre seus efeitos. Verificou-se que o isolado proteico de amaranto foi capaz de suprimir a hipercolesterolemia quando a dieta hipercolesterolemizante foi introduzida em paralelo a este ingrediente, com valores inferiores em 72 por cento (triglicerídeos), 64 por cento (colesterol total), 80 por cento (LDL-c) do grupo I em relação ao grupo H. Foi observada ainda menor concentração de colesterol e lipídeos totais no fígado dos animais do grupo I em relação ao grupo H (177 x 464 mg de colesterol/100 g de tecido; 2,06 x 2,86 g de lipídeos/100 g de tecido, respectivamente). Parâmetros lipídicos do sangue, das fezes e do fígado foram similares aos do grupo N, cuja dieta seguiu a preconização para roedores. Foi observada maior excreção de colesterol total no grupo I em relação ao grupo H, mas não houve maior excreção de ácidos biliares nas fezes. Não houve mudança na expressão dos genes analisados neste estudo, mas o amaranto reduziu a atividade da enzima Hmgcr. Postulase que parâmetros como expressão de Ldlr e atividade da Acat sejam alterados pela ingestão de amaranto. O perfil de ácidos graxos também foi modificado de forma a se assimilar ao grupo N, porém deve-se verificar parâmetros inflamatórios devido à maior proporção de ácido araquidônico em relação aos demais grupos estudados. Conclusão: Verifica-se biodisponibilidade dos peptídeos do amaranto e ação hipocolesterolemizante e hipolipemiante em diversas vias metabólicas, promovendo proteção cardiovascular. / Introduction: Cardiovascular diseases are important causes of death worldwide, and hypercholesterolemia is directly related to this public health problem. Diet plays an important role in this process and some foods such as amaranth (Amaranthus cruentus L. BRS-Alegria) have been shown to reduce plasma cholesterol. Studies suggest that this effect is related to peptides released during the digestion of proteins, which would play an important role in the modulation of lipid metabolism. Considering that the effects of gastrointestinal digestion and the absorption of these peptides are clearly complex, it is important to carry out studies aiming to evaluate their bioaccessibility and evaluation of the mechanisms of action of these peptides in the target sites of the organism. Objective: To analyze the bioavailability of peptides in animal models after ingestion of amaranth protein isolate and to relate it to parameters associated to cholesterol metabolism. Methods: The amaranth was crushed, the flour was defatted and its protein isolated. Amaranth peptides were analysed after in vitro digestion. Two in vivo experiments were conducted: one of acute phase and one of medium duration. In the first, the amaranth protein isolate was administered to rats and the peptides in the blood were monitored for 2 hours to check for fragments that resisted gastrointestinal digestion. The in vivo experiment 2 consisted of feeding three groups of hamsters, one with a diet recommended by AIN93 (group N) and two with hypercholesterolemic diets for 21 days, containing amaranth protein as the only dietary protein (group I), compared to casein control (group H). In this experiment were analyzed in the plasma: peptides, total cholesterol and fractions; In feces: total cholesterol and bile acids; In the liver: cholesterol, total lipids, fatty acids, Hmgcr enzymatic activity, Hmgcr expression, Srebf-2, Lxr, Abca1, Abcg8 and Ampk. Results and discussion: Peptide fragments from the in vitro digestion of amaranth protein isolate were identified and other dozens of peptide sequences were found in rats after acute amaranth administration. A higher number of peptides were found in the serum in relation to the plasma of the animals. Remarkably, ALGV peptide was found in serum of rats. This peptide is present in amaranth protein, according to databases, and is similar to fragments that present hypocholesterolemic action. In the blood of hamsters it could be found six peptides with 100 per cent coverage and similarity to the database of amaranth proteins, deserving investigation about their effects. Amaranth protein was able to suppress hypercholesterolemia when the hypercholesterolemic diet was introduced in parallel with this ingredient, with values lower for group I in 72 per cent (triglycerides), 64 per cent (total cholesterol), 80 per cent (LDL-c) in relation to the H group. A lower concentration of cholesterol and total lipids were observed in the liver of the group I compared to the H group (177 x 464 mg cholesterol / 100 g of tissue, 2.06 x 2,86 g lipids / 100 g of tissue, respectively). Lipid parameters of blood, faeces and liver were similar to those of group N, whose diet followed the recommendation for rodents. There was greater excretion of total cholesterol in group I in relation to group H, but there was no greater excretion of bile acids in feces, indicating that the effect of amaranth protein may be due to increased transintestinal cholesterol excretion, decreased micellar solubilization of cholesterol and / or modification in the expression of cholesterol transport related proteins in the intestine. There was no change in the expression of the genes analyzed in this study, but amaranth reduced the activity of the Hmgcr enzyme. It is postulated that parameters such as Ldlr expression and Acat activity are altered by amaranth intake. The fatty acid profile was also modified in order to assimilate to the N group, but inflammatory parameters related to amaranth intake should be verified due to the higher proportion of arachidonic acid in relation to the higher proportion of arachidonic acid in relation to the other groups studied. Conclusion: The bioavailability of amaranth peptides and hypocholesterolemic and hypolipidemic activity in several metabolic pathways is verified, therefore promoting cardiovascular protection.

Non-alcoholic fatty liver disease (NAFLD) results from an unequal uptake/storage and export/oxidation of lipids within the liver and is often a secondary disease to type II diabetes (22). NAFLD causes this imbalance of lipids by altering glucose and lipid metabolism, which corresponds to a decrease in mitochondrial function leading to failure of the liver. One established treatment for type II diabetes and NAFLD is the drug metformin, which has similar properties to the newly discovered CTRP 3 protein which is part of a group of bioactive molecules secreted by adipose tissue, collectively termed adipokines (2-4). Both have similar effects on hepatic glucose and lipid metabolism and both specifically suppress hepatic gluconeogenesis (11, 17, 27, 29). The revolutionary Seahorse extracellular flux analyzer was used to measure the metabolism of H4IIE hepatocytes without use of radiolabeling (1). By detecting the Oxygen Consumption Rate (OCR) of hepatocytes the level of metabolic function within mitochondria can be measured. Once an effective protocol was established using this new technology, hepatocytes treated with metformin had a significantly lower OCR compared to control treated hepatocytes treated. However, H4IIE hepatocytes treated with metformin and palmitate had a significant increase in OCR and eventually equilibrated with the lower OCR of hepatocytes solely treated with metformin. With similar effect, hepatocytes treated with CTRP3 and palmitate caused a drastic increase in OCR while hepatocytes treated with only CTRP3 had a decrease in OCR. This suggests that CTRP3 increases fatty acid oxidation which decreases lipid concentrations within hepatocytes which could mean future protection of liver against NAFLD. In conclusion, our Seahorse XF analyzer models compare metformin and CTRP3’s similarities and suggest the possible liver protective functions of CTRP3. Our results will aid in future research of CTRP3 to further determine its possible uses as a treatment for liver-associated diseases.

<p>Stroke is the major cause of serious long-term disability with a sufficient acute treatment for only a very limited number of patients. Limited recovery of neurological functions occurs and can be elevated by a permissive post-stroke milieu. Housing animals in an enriched environment modulates regenerative mechanisms in the nonischemic peri-infarct area which might be an attractive target for pharmacological treatments to promote recovery.</p><p>Upon ischemia, cellular lipids are released due to massive cell damage and free lipids significantly contribute to the progression of acute and delayed cell death. The aim of this study was to evalute the effect of enriched environment on lipid metabolism. In particular we characterize the activation of the transcription factor liver X receptor (LXR) in glial scar formation and regulation of cholesterol balance of relevance for functional recovery following stroke.                                      Brain tissues from animals subjected to permanent occlusion of middle cerebral artery (pMCAo) were analysed for LXRα and β protein expression. We found an upregulation and an increased transcriptional activity of LXRβ in the peri-infarct area of rats housing in an enriched environment following pMCAO. Our data anticipate that enriched environment may have positive effects on lipid recycling in the ischemic hemisphere following experimental stroke.<strong></strong></p>

Stroke is the major cause of serious long-term disability with a sufficient acute treatment for only a very limited number of patients. Limited recovery of neurological functions occurs and can be elevated by a permissive post-stroke milieu. Housing animals in an enriched environment modulates regenerative mechanisms in the nonischemic peri-infarct area which might be an attractive target for pharmacological treatments to promote recovery. Upon ischemia, cellular lipids are released due to massive cell damage and free lipids significantly contribute to the progression of acute and delayed cell death. The aim of this study was to evalute the effect of enriched environment on lipid metabolism. In particular we characterize the activation of the transcription factor liver X receptor (LXR) in glial scar formation and regulation of cholesterol balance of relevance for functional recovery following stroke.                                      Brain tissues from animals subjected to permanent occlusion of middle cerebral artery (pMCAo) were analysed for LXRα and β protein expression. We found an upregulation and an increased transcriptional activity of LXRβ in the peri-infarct area of rats housing in an enriched environment following pMCAO. Our data anticipate that enriched environment may have positive effects on lipid recycling in the ischemic hemisphere following experimental stroke.

Hepatitis C virus (HCV) infects millions of people worldwide and is one of the leading causes of liver damage. Infection with HCV is strongly correlated with an increased risk of steatosis, or fatty liver disease, which is caused by a build-up of fat deposits in hepatocytes. All genotypes of HCV appear to cause some degree of steatosis in approximately 50% of infected individuals, especially in the presence of contributing host factors such as diabetes, obesity and alcoholism. However, approximately 70% of genotype 3a infections exhibit steatosis. Furthermore, successful clearance of the genotype 3a virus results in eradication of the steatosis, suggesting the genotype 3a virus may be able to directly cause steatosis.<p> Research suggests a role for the core protein of HCV, which forms the capsid of the virus, in the alteration of lipid metabolism pathways during infection. As such, I hypothesized that: 1) HCV alters lipid metabolism pathways and causes the build up of lipid in hepatocytes and the development of steatosis; 2) HCV-3a core protein has a differential or increased effect on these pathways in comparison to 1b core protein; and 3) other HCV proteins could also play a role in the altering of lipid metabolism. My research characterized the subcellular localization on lipid droplets of the HCV-3a core protein in comparison to HCV-1b core protein. It was found that HCV-3a core causes increased transcriptional activity from the Fatty Acid Synthase (FAS) promoter, an important enzyme involved in the synthesis of triglycerides in hepatocytes. In addition, one specific amino acid of HCV-3a core was determined to be partially responsible for this effect. Further research determined that the effect of HCV-3a core on FAS was dependent on the transcription factor Sterol Response Element Binding Protein-1 (SREBP-1) and the presence of HCV-3a core increased the processing and activity of SREBP-1. HCV core was also able to increase activity of Akt 1 and Akt2; inhibition of Akt activity resulted in decreased SREBP-1 activity thereby indicating that HCV core partially mediates SREBP-1 via Akt. Further experiments examined the role of another HCV protein, NS2, in these same lipid metabolism pathways. NS2 was also able to increase transcription from the FAS promoter via SREBP-1, suggesting that this HCV protein may also be important in the development of steatosis during HCV infection.<p> The evidence provided in these studies shows a very important role for HCV in altering lipid metabolism during infection that may lead to the development of steatosis. Current research suggests that the SREBP-1 pathway may be critical in the life cycle of the virus and these studies have provided important information on how lipid metabolism pathways are being changed by the virus. Hopefully this work can help identify potential treatment options for HCV that can slow down disease progression by preventing the development of steatosis or by decreasing viral replication.