Thesis / Doctor of Philosophy (PhD)

Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is a polyphenol that is most abundant in tea. It has been shown from many studies that consumption of EGCG can contribute to weight loss, however, the underlying mechanism is not fully understood. To determine how EGCG acts to reduce fat, an organism model Caenorhabditis elegans (C. elegans) is introduced, which is a useful animal system in exploring crucial biological mechanisms that are readily applicable to humans. In this study, different strains were raised for two days on a diet with or without 100µM and 200µM EGCG treatment: N2 (i.e., wild type) and mutants (i.e., knockdown of fat metabolism related genes). EGCG’s effect on fat reduction was characterized by triglyceride content, food consumption and physiological behaviors. Our results showed that 100 and 200 µM EGCG significantly reduced the triglyceride content of wild type worms by 10% and 20%, respectively, without affecting its food intake and physiological behaviors. Additionally, EGCG could effectively reduce fat accumulation in C. elegans dependent on acs-2 and atgl-1.

Fish meal (FM) and fish oil (FO) have traditionally been central in aquaculture feed formulation but the finite global supply situation limiting future use along with issues of contaminant levels in these feed ingredients have become critical issues. The objectives of the present study were to investigate alternative feed ingredients as substitutes for both FM and FO in feeds for Atlantic salmon (Salmo salar) to ensure optimal growth, feed efficiency and health of the fish as well as maintaining the nutritional quality of the fish product to the human consumer, especially the levels of n-3 highly unsaturated fatty acid (HUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in the flesh. The results of the present study revealed that there were no negative effects on growth performance, feed utilisation and apparent digestibility in Atlantic salmon when FO was substituted with vegetable oil (VO) but these parameters were affected when FM was replaced with alternative protein sources from plants and animals at high levels, despite dietary supplementation with crystalline amino acids and lecithin. Reduction in feed intake was a factor affecting growth retardation when FM inclusion decreased. However, replacing FM with alternative plant and animal proteins along with partial replacement of FO had no major effect on nutritional quality, particularly n-3 HUFA content of salmon tissues. Replacing Northern FO with decontaminated FO or blends of southern hemisphere FO and VOs strategies to reduce POP contaminants and retain high nutritional values in flesh were very successful. Dietary treatments and genetic origin of fish both had effects on tissue compositions and gene expression. All fish groups (strain/family), consist of CAL, LEAN and FAT strains, fed a diet containing VO showed significant differential expression of lipid metabolism-related genes compared to fish fed a FO diet with LEAN strain appearing to adapt to VO inclusion better than FAT strain. This thesis has demonstrated dual replacement of FM and FO with alternative raw materials in salmon feeds without a major negative impact on nutritional quality.

La sécrétion de lipase, la lipolyse extracellulaire et l’absorption des acides gras (AGL) ont été étudiés chez Yarrowia lipolytica (YL) en présence d’huile d’olive et/ou de sucrose. Des mesures d’activité lipase et d’immuno-révélation ont montré que l’activité lipase présente dans le milieu de culture provenait principalement de la lipase YLLIP2. L’huile d’olive induit la production de lipase qui est principalement associée aux cellules pendant les premières heures de cultures. YLLIP2 est ensuite libérée dans le milieu de culture avant d’être totalement dégradée par les protéases. Les triglycérides (TG) sont dégradés alors que la lipase est encore attachée aux cellules. Les produits de lipolyse présents dans le milieu de culture et à l’intérieur des cellules ont été quantifiés par chromatographie TLC-FID et GC. Les niveaux intracellulaires d’AGL et de TG augmentent transitoirement et dépendent de la source de carbone utilisée. Une accumulation maximum de 37,8 % w/w de lipides est observée avec l’huile d’olive seule. Cette étude montre que la levure YL est un modèle intéressant pour étudier la lipolyse extracellulaire et l’absorption des acides gras par les cellules / Lipase secretion, extracellular lipolysis and fatty acid (FFA) uptake were quantified in Yarrowia lipolytica (YL) grown in the presence of olive oil and/or sucrose. Lipase assays and western blot analysis indicated that the lipase activity measured in YL cultures mainly resulted from YLLIP2 lipase. Lipase production was triggered by olive oil and YLLIP2 remained associated with the yeast cells during the first hours of culture. It was then released in the culture medium before it was totally degraded by the alkaline protease. Olive oil triglycerides (TG) were degraded when the lipase was still attached to the cell wall. The fate of lipolysis products in the culture medium and inside the yeast cell were investigated by quantitative TLC-FID and GC analysis. Intracellular levels of FFA and TG increased transiently and were dependent on the carbon sources. A maximum fat storage of 37.8% w/w was observed with olive oil alone. The present study shows that yeasts are interesting models for studying extracellular lipolysis and fat uptake by the cell

Résumé Objectifs : Le syndrome métabolique (MetS) est un ensemble de composantes (obésité, résistance à l'insuline, intolérance au glucose, dyslipidémie, hypertension) qui sont associées à une augmentation du risque de diabète de type 2 et de maladies cardiovasculaires. Aux États-Unis, la fréquence du MetS atteint des proportions épidémiques avec une prévalence de 25% de la population. Les études nutritionnelles traditionnelles se sont concentrées sur l’effet d’un nutriment alors que les études plus récentes ont déterminé l’effet global de la qualité alimentaire sur les facteurs de risque. Cependant, peu d'études ont examiné la relation entre la qualité alimentaire et le MetS. Objectif: Déterminer l'association entre la qualité alimentaire et le MetS et ses composantes. Méthodes: La présence du MetS a été déterminée chez 88 femmes post-ménopausées en surpoids ou obèses, selon la définition du National Cholesterol Education Program Adult treatment Panel III alors que la qualité alimentaire a été évaluée selon le Healthy Eating Index (HEI). La sensibilité à l’insuline, la composition corporelle et le métabolisme énergétique ont été mesurés. Résultats: Le HEI corrélait négativement avec la plupart des mesures de masse grasse et du poids mais pas avec la sensibilité à l'insuline, l’hypertension et la plupart des marqueurs lipidiques. Cependant, l’HEI corrélait positivement avec LDL-C/ApoB et négativement avec le métabolisme énergétique. Conclusion: Les résultats démontrent que l’HEI est associé avec les mesures de gras corporel et la grosseur des LDL. Mots clés: Obésité, qualité alimentaire, métabolisme lipidique, syndrome métabolique. / Abstract Background: The metabolic syndrome (MetS) is a constellation of different metabolic components including central obesity, insulin resistance, abnormal glucose homeostasis, dyslipidemia and high blood pressure which identify individuals at high risk of type 2 diabetes and cardiovascular events. In the US, the prevalence of MetS has reached epidemic proportion and up to 25% of the population is affected. Traditional nutritional studies have focused on a single nutrient. Recently, measures of overall diet quality have been proposed as an alternative to assess diet-related diseases. However, few studies have addressed the relationship between diet quality and the MetS. Objective: To investigate the association of diet quality with the MetS and its components. Methods: The presence of the MetS was determined in 88 postmenopausal overweight or obese women using the National Cholesterol Education Program Adult treatment Panel III definition while diet quality was assessed with the Healthy Eating Index (HEI). We also measured insulin sensitivity, body composition and energy metabolism. Results: The HEI correlated negatively with most measures of body fat and body weight but not with insulin sensitivity, blood pressure and most markers of lipid metabolism. However, HEI correlated positively with LDL-C/ApoB and negatively with energy metabolism. Conclusion: Our results demonstrated that HEI is associated with fat distribution and LDL size. Key words: Obesity, diet quality, lipid metabolism, metabolic syndrome.

High-value industrial oils are essential for many processes and have great economic and environmental impacts. The tung tree produces a high-value seed oil. Approximately 80% of tung oil is α-eleostearic acid, which has a high degree of unsaturation thus giving it properties as a drying oil. The identification of the biological components in tung is imperative to further the knowledge of its processes. Four unique tung acyl-CoA binding proteins, VfACBP3a, VfACBP3b, VfACBP4, and VfACBP6 were identified and the genes encoding them were cloned and analyzed to determine their biological roles. The VfACBPs were observed to be similar to other organisms' ACBPs, especially Arabidopsis thaliana. In addition, each gene was expressed in all tung tissues. They were shown to interact with VfDGAT1 and VfDGAT2, two known components of tung lipid metabolism. Finally, VfACBP3a and VfACBP6 were expressed in the seeds of transgenic plants to study the effects of VfACBP expression on seed lipid fatty acid content.

Camundongos Swiss, quando submetidos à dieta hiperlipídica (HL), apresentam considerável ganho ponderal e de depósitos adiposos, tornando-se obesos e resistentes à insulina. O objetivo deste trabalho foi avaliar o efeito da dieta HL por 8 semanas no perfil inflamatório, síntese de triacilglicerol (TAG) com ênfase na vias de geração de glicerol-3-fosfato (G3P) e lipólise nos tecidos adiposos brancos (TAB) retroperitoneal (RETRO) e epididimal (EPI) de camundongos. Camundongos Swiss foram alimentados com as dietas: controle (CT) - dieta purificada (AIN-93G); ou HL - dieta AIN-93G modificada contendo 35% de lipídeos (4% de óleo de soja e 31% de gordura suína). Os camundongos alimentados com a dieta HL apresentaram uma maior massa corporal, acompanhada pelo aumento nos tecidos RETRO e EPI, além de desenvolverem resistência à insulina constatada no teste de tolerância à glicose (TTG), hiperglicemia e hiperinsulinemia. O conteúdo protéico da pAKT, avaliado por western blot (WB), e a adiponectina, dosada em homogenados dos tecidos adiposos, estão reduzidos apenas no EPI. Houve aumento na expressão gênica de MCP-1 e PAI-1, e foi observada menor área dos adipócitos no EPI, sem alteração no RETRO dos animais HL. A síntese de novo de ácidos graxos (AG), avaliada pela incorporação de 3H de 3H2O em AG foi maior em ambos os TAB, porém a captação de AG das lipoproteínas circulantes avaliada pela atividade e expressão da lipase lipoproteica (LPL) aumentou no EPI e reduziu no RETRO. A dieta HL induziu aumento na fosforilação do glicerol, avaliada pela atividade e conteúdo da GK que aumentaram nos dois TAB, e maior incorporação de 1-14C-glicerol em TAG no EPI. A captação de glicose in vitro e conteúdo do GLUT- 4, que indicam atividade da via glicolítica foram reduzidos no EPI e RETRO, assim como a gliceroneogênese avaliada pela incorporação de 1-14C-piruvato em TAG, sem alterações na atividade e conteúdo da fosfoenolpiruvato carboxiquinase (PEPCK). A atividade lipolítica basal foi avaliada in vitro pela liberação de glicerol por adipócitos isolados, e não foi alterada pela ingestão de dieta HL, porém quando estimulada por noradrenalina a liberação de glicerol foi menor nos animais HL, assim como as fosforilações da ATGL e HSL e conteúdo do receptor adrenérgico ?3. A dieta HL levou a uma redução no conteúdo de PPAR? e aumento de ATF3 em ambos os tecidos. No EPI houve aumento de pCREB, pSTAT3 e RGS2 em relação aos controles enquanto no RETRO a única diferença encontrada foi a menor pSTAT3. Nossos resultados demonstram que o aumento nos TAB é resultado de maior síntese e captação de AG, e que o G3P necessário para a esterificação a TAG é proveniente principalmente da fosforilação direta do glicerol pela GK; além disso, a reduzida lipólise também parece contribuir para esse quadro. Nos animais HL, o EPI parece ser mais propenso aos efeitos da dieta do que o RETRO / Swiss mice when subjected to high fat diet (HFD), shown considerable weight gain and adipose depots, becoming obese and insulin resistant. The aim of this study was to evaluate the effect of HFD diet for 8 weeks in the inflammatory profile, triacylglycerol (TAG) synthesis with emphasis in glycerol-3-phosphate (G3P) generation pathways and lipolysis in retroperitoneal (RETRO) and epididymal (EPI) white adipose tissue (WAT) of mice. Swiss mice were fed with diets: control (CT) - purified diet (AIN-93G); or HFD - purified diet (AIN-93G) plus 35% of fat (4% soybean oil and 31% of lard). Mice fed a HFD diet had a higher body mass, accompanied by an increase in RETRO and EPI tissues, in addition to developing insulin resistance, evidenced by glucose tolerance test (GTT), hyperglycemia and hyperinsulinemia. The protein content of pAKT, accessed by western blot, and adiponectin, measured in WAT homogenates, are reduced only in EPI. There was an increase in gene expression of MCP-1 and PAI-1, and was observed smaller area of adipocytes in EPI, with no change in RETRO of HFD fed animals. De novo synthesis of fatty acids (FA), evaluated by incorporation of 3H from 3H2O in FA was higher in both TAB, but the uptake of FA, from blood lipoproteins, evaluated by the activity and expression of lipoprotein lipase (LPL) was increased in EPI and reduced in RETRO. HFD induced increase in phosphorylation of glycerol, evaluated by the activity and content of glycerolkinase (GyK) which increased in both TAB and greater incorporation of 1-14C-glycerol in the TAG only in EPI. The in vitro glucose uptake and GLUT-4 content, which indicates the activity of the glycolytic pathway were reduced in EPI and RETRO, as well as glyceroneogenesis assessed by the incorporation of 1-14C- pyruvate into TAG without changes in the activity and contents of phosphoenolpyruvate carboxykinase (PEPCK). The basal lipolytic activity was evaluated in vitro by glycerol releasing from isolated adipocytes, and was not altered by HFD intake, but when stimulated by noradrenaline glycerol release was lower in HFD animals as well as the phosphorylation of ATGL and HSL and ?3 adrenergic receptor content. HFD led to a reduction in the content of PPAR gamma and an increase in ATF3 in both tissues. In EPI there was an increase in pCREB, pSTAT3 and RGS2 while in RETRO the only difference was reduced pSTAT3. Our results shown that TAB increase is result of increased FA synthesis and uptake, and G3P required for esterification TAG comes mainly from direct phosphorylation of glycerol by GyK; Furthermore, reduced lipolysis also seems to contribute to this scenario. HFD effects seem to be more prominent in EPI than in RETRO

Estima-se que 3% da população mundial esteja infectada pelo vírus da hepatite C (HCV). O HCV tem como alvo o tecido hepático e a maioria dos pacientes infectados desenvolvem infecção crônica. Nos últimos anos, estudos in vitro têm demonstrado interações entre o miRNA-122 (miR-122) da célula hospedeira e dois sítios localizados na região 5\' UTR do genoma do vírus da hepatite C (HCV), os quais são essenciais ao processo de replicação viral. O miR-122 é altamente expresso no fígado, onde atua na regulação do metabolismo de lipídios juntamente com outro miRNA, o miRNA-33a (miR-33a), porém, o mecanismo envolvido nesta regulação ainda é pouco conhecido. Sabe-se que a infecção pelo HCV altera a expressão de genes envolvidos na biossíntese e transporte de lipídios, resultando na estimulação do metabolismo de lipídios e criando um ambiente favorável para sua replicação. Neste contexto os objetivos deste trabalho foram avaliar a expressão de miR-33a e miR-122 em indivíduos cronicamente infectados pelo HCV-1 e HCV-3 em amostras obtidas antes do início da terapia. Os miRNAs foram isolados a partir de amostras de sangue periférico e de tecido hepático. A quantificação da expressão relativa de ambos miRNAs foi pela técnica de PCR em tempo real. Os níveis de miR-33a no sangue periférico foram mais elevados do que no tecido hepático em indivíduos infectados pelo HCV-1(p < 0,0001) e HCV-3 (p=0,0025). Observou-se uma correlação inversa entre os níveis de miR-33a no sangue periférico e tecido hepático dos indivíduos infectados pelo HCV-1 (r=-0,281, p=0,039) e correlação positiva para os indivíduos infectados pelo HCV-3 (r=0,9286, p < 0,0001). Correlação inversa entre os níveis hepáticos de miR-33a com o nível sérico de insulina (r=-0,371, p =0,005) nos indivíduos infectados pelo HCV-1 e correlação positiva entre os níveis no sangue periférico com os níveis séricos de GGT (r=0,553, p=0,049) foram observadas. Em relação ao miR-122, de maneira geral o nível hepático foi mais elevado do que o sérico (p < 0,0001). Entretanto, o nível hepático de miR-122 em indivíduos infectados pelo HCV-3 foi maior quando comparado aos infectados pelo HCV-1 (6,22 vezes, p < 0,001). Uma correlação inversa entre os níveis séricos de ApoA-II e os níveis de expressão de miR-122 no sangue (r=-0,330; p=0,014) e tecido hepático (r=-0,311; p=0,020) foi observada nos pacientes infectados pelo HCV-1. Os pacientes infectados pelo HCV- 3 mostraram correlação positiva entre os níveis hepáticos de miR-122 e os níveis de HDL (r=0,412, p=0,036) e insulina (r=0,478, p=0,044). O miR-33a e o miR-122 atuam regulando genes que controlam o metabolismo dos lipídios no fígado. Até o presente momento, não existem relatos que associem a expressão do miR-33a e do miR-122 com o perfil lipídico na infecção pelo HCV. Além disso, o acúmulo de lipídio (esteatose) intensamente descrito na infecção pelo HCV-3 pode sugerir interação diferenciada desse genótipo com os mecanismos envolvidos na regulação do metabolismo lipídico, envolvendo o miR-33a e miR-122 / The prevalence of infection by hepatitis C virus (HCV) is about 3% of the world population. HCV targets the liver tissue and the majority of infected patients develop chronic infection. In recent years, in vitro studies have demonstrated interactions between miRNA-122 (miR-122) the host cell to two places located in the 5\' untranslated region of the HCV genome which are essential for virus replication process. miR-122 is highly expressed in the liver, which has been implicated as a fatty acid metabolism regulator. Another mine has also been described as a key regulator of lipid metabolism, miRNA-33a (miR-33a), however, the mechanisms involved in this regulation are still little known. It is known that HCV infection changes the expression of genes involved in the biosynthesis and transport of lipids, resulting in stimulation of the lipid metabolism and creating a favorable environment for replication of the virus. To our knowledge, there are no reports linking the expression of miR-33a with lipid profile in HCV infection. In this context the objectives of this study were to evaluate the expression of miR-33a and miR-122 in chronically infected individuals with HCV-1 and HCV-3 in samples obtained prior to initiation of therapy. MiRNAs were isolated from peripheral blood samples and liver tissue. The quantification of relative expression of both miRNAs was by PCR in real time. MiR-33a levels in peripheral blood were higher than in liver tissue in patients infected with HCV-1 (p < 0.0001) and HCV-3 (p=0.0025). Levels in the peripheral blood of miR-33a were lower in patients infected with HCV-3 (p=0.0169). There was an inverse correlation between hepatic levels of miR-33a with serum insulin levels (p=0.005) in individuals infected with HCV-1 and a positive correlation between the levels in the peripheral blood serum levels of GGT (p=0.049). Hepatic levels of miR-122 were higher than the levels in the peripheral blood of individuals infected by HCV-1 and HCV-3 (p < 0.0001). Hepatic miR-122 levels were higher in patients infected with HCV-3 than those infected with HCV-1 (6.22 times, p < 0.001). There was a positive correlation between miR-122 levels in the blood and liver tissue of patients infected with HCV-1 (r=0.302, p=0.026). An inverse correlation between serum ApoA-II was observed in these patients the levels of expression of miR-122 in blood (r=-0.330; p =0.014) and liver tissue (r=-0.311; p=0.020). Patients infected with HCV-3 showed a positive correlation between hepatic miR-122 levels to HDL levels (r=0.412, p=0.036) and insulin levels (r=0.478, p=0.044). The miR-33a and miR-122 act by regulating genes that control lipid metabolism in the liver. The different interactions with lipid metabolism exerted by HCV-3 may explain why his relationship with the miR-33a and miR-122 was different when compared with HCV-1

Introdução:Uma das causas da doença cardiovascular do diabético é a dislipidemia associada ao diabetes mellitus tipo 2 (DM2), caracterizada basicamente por hipertrigliceridemia e baixa concentração de HDL-colesterol. O bom controle da glicemia geralmente resulta em diminuição dos triglicerídeos plasmáticos, mas há controvérsia na literatura quanto aos níveis de HDL-colesterol e outros parâmetros lipídicos. As transferências lipídicas para a HDL têm importante função na sua formação e remodelamento e no seu papel antiaterogênico do transporte reverso do colesterol. A transferência de lípides entre as lipoproteínas é bidirecional e depende da estrutura e concentração da lipoproteína doadora e receptora, assim como da ação das proteínas de transferências, CETP e PLTP. Objetivo:Investigar as relações dos níveis glicêmicos com as transferências lipídicas para a HDL e com outros parâmetros do metabolismo lipídico em pacientes com DM2. Métodos:143 pacientes com DM2, que não estavam usando drogas hipolipemiantes, foram selecionados e separados em dois grupos: grupo com hemoglobina glicada (HbA1c) <= 6,5% (n=62) e grupo com HbA1c > 6,5% (n=81). O método in vitro de transferência lipídica para a HDL foi realizado através da incubação sob agitação, por 1 hora, de uma nanoemulsão doadora contendo colesterol esterificado e não esterificado, fosfolipídios e triglicerídeos, marcados radioativamente, com o plasma do paciente, seguido de precipitação química e contagem dos lipídios radiomarcados transferidos para HDL. Outras determinações plasmáticas do metabolismo lipídico também foram realizadas. Foi também verificado o percentual de pacientes nos dois grupos com o perfil lipídico dentro das metas estabelecidas pela American Diabetes Association. Pacientes com ou sem uso de insulina e com níveis maiores e menores de ácidos graxos livres (AGL) foram comparados quanto aos parâmetros estudados. Resultados:O grupo HbA1c > 6,5% apresentou maior trigliceridemia (205±115 vs 140±54mg/dl; p < 0,0001) e colesterol não esterificado (36,4±7,6 vs 33,7±5,7mg/dl; p > 0,05), além de apresentar maior concentração de triglicerídeos na partícula de HDL (9,2±2,8 vs 8,1±2,3%; p < 0,05), do que o grupo HbA1c<=6,5%. As concentrações de triglicerídeos, colesterol total e não esterificado e também o colesterol da fração não-HDL correlacionaram-se positivamente com a HbA1c (r=0,25, r=0,19, r=0,18, r=0,17, respectivamente, p < 0,05). A concentração de colesterol esterificado da HDL correlacionou-se negativamente com a HbA1c (r=-0,19, p < 0,05). Os pacientes com HbA1c <= 6,5% atingiram mais a meta trigliceridêmica do que os com HbA1c > 6,5% (66 vs 37%; p < 0,001). Os pacientes com maiores níveis de AGL tiveram maior trigliceridemia (196±105 vs 153±81 mg/dl; p < 0,01) e atividade de LCAT (1,36±0,10 vs 1,29±0,10 470/390nm; p < 0,01), além de uma maior concentração de triglicerídeos na partícula de HDL (9,4±2,9 vs 7,8±2,0%; p < 0,001), em relação aos pacientes com menores níveis de AGL. A transferência dos quatro lipídios da nanoemulsão para a HDL foi igual na comparação de todos os grupos deste estudo. Conclusão:Os resultados deste estudo mostraram pela primeira vez que junto com os triglicerídeos, o colesterol não esterificado é também um marcador de pobre controle glicêmico em pacientes com DM2 / Introduction:One cause of cardiovascular disease (CVD) of patients with type 2 diabetes mellitus (T2DM) is diabetic dyslipidemia, characterized primarily by hypertriglyceridemia and low HDL-cholesterol. Good blood glucose control usually results in decreased plasma triglycerides, but there is controversy in the literature as to the levels of HDL-cholesterol and other lipid parameters. Lipid transfers to HDL play an important role in the formation and remodeling of HDL and on its antiatherogenic role of reverse cholesterol transport. The transfer of lipids between lipoproteins is bidirectional and depends on the structure and concentration of the donor and acceptor lipoprotein as well as the action of the transfers proteins, PLTP and CETP. Objective:Investigate the relationship of blood glucose levels with lipid transfers to HDL and other parameters of lipid metabolism in patients with T2DM. Methods:143 patients with T2DM, who were not using lipid-lowering drugs, were selected and divided into two groups: group with glycated hemoglobin (HbA1c) <= 6.5% (n=62) and group with HbA1c > 6.5% (n=81). In vitro lipid transfers to HDL was performed by 1 hour incubation under stirring of a donor nanoemulsion containing radioactively labeled unesterified and esterified cholesterol, phospholipids and triglycerides with whole patient plasma, followed by chemical precipitation and counting of radiolabeled lipids transferred to HDL. Other determinations of plasma lipid metabolism were also performed. It was also checked the percentage of patients in both groups with lipid profile within the targets set by the American Diabetes Association criteria. Patients with or without insulin use and with higher and lower free fatty acids (FFA) levels were also compared for the studied parameters. Results:HbA1c>6.5% group had higher triglyceridemia (205 ± 115 vs 140 ± 54 mg/dl, p<0.0001) and unesterified cholesterol (36.4 ± 7.6 vs 33.7 ± 5.7 mg/dl, p<0.05) than the HbA1c<=6.5% group. The concentrations of triglycerides, total and unesterified cholesterol and also non-HDL cholesterol was positively correlated with HbA1c (r=0.25, r=0.19, r=0.18, r=0.17, respectively, p<0,05). The concentration of esterified cholesterol from HDL was negatively correlated with HbA1c (r = -0.19, p<0.05). Patients with HbA1c<=6,5% achieved more the triglyceridemic target than the patients with HbA1c>6.5% (66 vs 37%, p<0.001). Patients with higher levels of FFA had higher triglycerides levels (196 ± 105 vs 153 ± 81 mg/dl, P<0.01) and LCAT activity (1.36 ± 0.10 vs 1.29 ± 0.10 470/390nm, p<0.01), in addition to a higher concentration of triglycerides in the HDL particle (9.4 ± 2.9 vs 7.8 ± 2.0%, p <0.001). The transfer of the four lipid of the nanoemulsion to HDL was equal in the comparison of all the studied groups. Conclusion:The results of this study showed for the first time that unesterified cholesterol, along with triglycerides, is also a marker of poor glycemic control in patients with T2DM

Herz-Kreislauf-Erkrankungen als Folge arteriosklerotischer Prozesse sind die häufigste Todesursache weltweit. Lipidstoffwechselstörungen sind ein wichtiger Risikofaktor für die Pathogenese der Arteriosklerose. Komplexe Phänotypen, wie z.B. der Lipidstoffwechsel, werden durch eine Vielzahl von genetischen und Umweltfaktoren beeinflusst. Obwohl der Lipidstoffwechsel biochemisch gut charakterisiert ist und viele Gene, die für Proteine innerhalb des Lipidstoffwechsels kodieren bekannt sind, sind die spezifischen genetischen Faktoren, die die Variabilität des Lipidstoffwechsels beeinflussen, weitgehend unbekannt. Die vorgelegten Studien zeigen verschiedene Ansätze, wie genetische Faktoren, die die Variabilität des Lipidstoffwechsels beeinflussen, identifiziert und quantifiziert werden können. Dabei wird ein besonderer Schwerpunkt auf die Untersuchung der Variabilität im nicht-pathologischen Bereich des Stoffwechsels gelegt. Im Rahmen der durchgeführten Arbeiten wurden: 1. modifizierende Genorte bei familiären Hyperlipidämien identifiziert. Dieser Ansatz wurde am Beispiel von zwei Familien mit familiärer Hypercholesterinämie aus Israel und Syrien illustriert. Mit Hilfe der Familie aus Israel wurde ein Genort, der für einen Cholesterin-senkenden Effekt verantwortlich ist, kartiert. Mit Hilfe der Familie aus Syrien wurde ein Gen für die Ausprägung von Xanthomen postuliert. 1. der Einfluß von Genen und Genorten auf die Variabilität des Lipidstoffwechsels in einer Zwillingspopulation nachgewiesen. Dieser Anstz wurde anhand von Genorten auf Chromosom 13q (Cholesterin-senkender Genort), auf Chromosom 8 (Lipioprotein Lipase und Makrophagen Scavenger Rezeptor) und dem PPAR?-Gen auf Chromosom 3 illsutriert. 3. der Einfluß einzelner genetischer Varianten in sechs Kandidatengenen des Lipidstoffwechsels in einer familienbasierten Stichprobe quantifiziert. 4. ein mathematisches Modell des Lipidstoffwechsels entwickelt, mit dem Ziel, sich der Komplexität des Stoffwechsels sowohl von experimenteller als auch von theoretischer Seite her zu nähern. / Cardiovascular disease resultung from atherosclerotic processes are the most commonest cause of death worldwide. Lipid disturbances are a major risk factor in the pathogenesis of atherosclerosis. Complex phenotypes, e.g. lipid metabolism, are influenced by a variety of genetic and environmental factors. Although lipid metabolism is well characterized biochemically and many genes, coding for proteins of lipid metabolism are known, the specific genetic variants, influencing the variability of lipid metabolism are largely unknown. The studies presented show different approaches to the identification of genetic factors contributing quantitatively and qualitatively to the variability of lipid metabolism. This work puts an emphasis on the variability in the non-pathological range of lipid concentrations. The following issues are addressed in the context of this work: 1. Identification of modifying genes of familial lipid disorders. This approach is illustrated for two families with familial hypercholesterolemia from Israel and Syria. The family from Israel allowed the mapping and identification of a cholesterol-lowering gene locus. The family from Syria helped postulating a giant xanthoma gene. 2. The influence of genes and gene loci on the variability of lipid metabolism using a twin cohort. This approach was illustrated for gene loci on chromosome 13q (cholesterol-lowering gene locus), chromosome 8 (Lipoprotein lipase and macrophage scavenger receptor gene locus), and the PPAR?-gene on chromosome 3. 3. The influence of single nucleotide polymorphisms in six lipid metabolism relevant genes using a family based association approach. 5. A mathematical model of lipid metabolism was developed. The goal was to approach the complexity of lipid metabolism experimentally as well as theoretically.