PCSK9 est un régulateur clé du métabolisme du cholestérol par le foie à travers la dégradation lysosomiale du récepteur aux LDL (low-density lipoprotein). Alors que les mutations gain de fonction (GOF) de PCSK9 induisent une hypercholestérolémie autosomique dominante, les mutations pertes de fonctions (LOF) entraînent un taux spontanément bas de LDL-cholestérol, ainsi qu’un protection cardiovasculaire. Du fait des limitations inhérentes aux modèles d’études, tels que les lignées cellulaires transfectées ou des animaux transgéniques, les fonctions de PCSK9 restent encore mal connues. Ainsi, nous avons utiliser des cellules souches pluripotentes induites (hiPSC) spécifiques de patients pour les différencier en hépatocytes et modéliser la physiopathologie liée aux mutations de PCSK9 GOF-S127R et LOF-R104C/V114A. Nous avons démontré que les hépatocytes obtenus récapitulaient la physiopathologie liés aux mutations de PCSK9. De plus, les cellules portant la mutation S127R ont montré une importante réponse au traitement par les statines, qui est corrélée à la réponse clinique des patients portant cette même mutation. Enfin, notre étude nous a permis de mettre à jour une fonction inattendue de PCSK9 dans les hiPSC et pendant leur différenciation. Elle montre que PCSK9 affecterait la prolifération des hiPSC ainsi qu’une voie de signalisation clé du développement régulée par NODAL. Cette régulation se ferait à travers une interaction directe entre PCSK9 et DACT2, un régulateur intracellulaire de la voie de signalisation de NODAL. En conclusion, les hiPSC s’avèrent être un modèle cellulaire translationnel pertinent pour mettre à jour de nouvelles fonctions hépatiques de PCSK9. / PCSK9 has been identified as a key regulator of cholesterol metabolism by the liver through inducing lysosomal degradation of the low-density lipoprotein receptor (LDLR). While PCSK9 gain-of-function (GOF) mutations induced autosomal dominant hypercholesterolemia and increased cardiovascular risk, loss-of-function (LOF) mutations are associated with low LDL-cholesterol levels and cardiovascular protection. Due to limitations inherent to current models including animal and human cells lines transfected with DNA constructs or transgenic animal models, PCSK9 functions are not fully understood. Therefore, we took advantage of patient related somatic cells reprogramming intoinduced pluripotent stem cells (hiPSC) to generate hepatocyte-like cells (HLC) and model the pathophysiology of PCSK9 mutations in dyslipidemia through focusing on two intracellular mutation forms; GOF (S127R) and LOF (R104C/V114A). We showed that HLC could recapitulate the key pathophysiological features of PCSK9 mutations. Moreover, HLC with the S127R mutation displayed an increased uptake of LDL upon statin treatment, which was correlated with the original patient clinical response. In parallel, this model enabled us to unravel a new unexpected role of PCSK9 in hiPSC and during differentiation. PCSK9 was found to affect the proliferation of hiPSC and regulate a key developmental signaling pathway mediated by NODAL. This regulation might occur by a direct interaction between PCSK9 and DACT2, an intracellular attenuator of NODAL signaling pathway. In conclusion, hiPSC provide a pertinent translational model to decipher PCSK9 hepatic functions and a novel cellular environment to highlight new functions.

No description available.

The global prevalence of chronic kidney disease (CKD) has risen at an accelerating rate, increasing the global healthcare burden for long-term and chronic care costs. Multiple risk factors including hypertension, diabetes, and dyslipidemia synergistically induce the progression of CKD. Chief among these factors are dyslipidemia and obesity; increased free fatty acid uptake due to excess consumption of lipid-rich diets has been shown to promote intra-renal lipid accumulation in several in vivo models and in patients in various stages of CKD. Furthermore, patients with renal disease are also at a substantially higher risk for atherosclerotic cardiovascular disease (CVD). In the general population, as well as in patients with renal disease, circulating low-density lipoprotein cholesterol (LDLc) is a well-established driver of atherosclerotic lesion development and CVD progression. In 2003, the proprotein convertase subtilisin/kexin type-9 (PCSK9) was identified as the third locus of familial hypercholesterolemia and was further characterized for its ability to enhance the degradation of the low-density lipoprotein receptor (LDLR). Since this seminal discovery, the development of monoclonal antibodies targeted against PCSK9 demonstrated a significant reduction in LDLc and subsequent CVD risk, establishing the remarkable ‘bench to bedside’ transition. However, the inherent role of PCSK9 in regulating lipid homeostasis remained unknown in different pathological conditions. In the first chapter of my thesis, I demonstrate that PCSK9 regulates the LDLR as a feedback mechanism to protect against non-alcoholic steatohepatitis (NASH) progression induced by a high-fat diet (HFD) challenge. Since its seminal discovery, PCSK9 was also characterized to modulate a wide variety of receptors known to play a crucial role in lipid metabolism including the cluster of differentiation 36 (CD36), the very low-density lipoprotein receptor (VLDLR), and the apolipoprotein E receptor 2 (ApoER2). Previously, we have demonstrated that the absence of PCSK9 promotes diet-induced non-alcoholic steatohepatitis and liver injury through increased surface expression of CD36. Given that these same receptors are well-expressed on renal epithelia, the second chapter of my thesis demonstrates that PCSK9 is also able to modulate renal lipid metabolism by attenuating tubular lipid accumulation and subsequent renal injury. Furthermore, when PCSK9 was first characterized by Seidah and colleagues in 2003, in situ hybridization of murine PCSK9 demonstrated that it was primarily expressed in the liver, but also well-expressed in the kidney cortex, cerebellum, and small intestines. Despite its expression in a wide range of tissues, the secretion of PCSK9 was exclusive to the liver, thus, questioning what the intracellular role of PCSK9 may be. Hence, my last chapter of my masters studies lies in establishing the role of intracellular PCSK9 expression in a cellular process known as endoplasmic reticulum (ER) stress in the kidney. ER stress is a phenomena which primarily occurs due to increased accumulation of misfolded polypeptides, and has been implicated in numerous metabolic diseases including hepatic steatosis, CKD, and neurodegenerative pathologies. Previously, we have demonstrated that overexpressing wild-type and variants of PCSK9 in a Pcsk9-/- mouse does not induce the activation of the unfolded protein response (UPR) and attenuates hepatic ER stress. Using a well-established CKD model, I show that Pcsk9-/- mice exhibit increased renal ER stress and injury relative to wild-type controls. Overall, my findings demonstrate for the first time that both extracellular and intracellular PCSK9 has the ability to modulate renal injury using two distinct mechanism to protect against CKD progression. / Thesis / Master of Health Sciences (MSc)

Calcific aortic valve disease (CAVD) is associated with significant cardiovascular morbidity. While late-stage valve disease is well-described, there remains an unmet scientific need to elucidate early pathobiological processes. In CAVD, pathological differentiation of valvular interstitial cells (VICs) and lesion formation occur focally in the fibrosa layer. This VIC pathological differentiation has been shown to be influenced by matrix stiffness in vitro. However, little is known about the focal layer specific mechanical properties of the aortic valve in health and disease and how these changes in matrix moduli may influence VIC pathological differentiation in vivo. In this thesis, micropipette aspiration (MA) was shown to be capable of measuring the mechanical properties of a single layer in multilayered biomaterial or tissue such as the aortic valve, if the pipette inner diameter was less than the top layer thickness. With MA, the fibrosa of normal porcine aortic valves was significantly stiffer than the ventricularis; stiffer locations found only within the fibrosa were comparable to stiffnesses shown in vitro to be permissive to VIC pathological differentiation. Early CAVD was induced in a porcine model, which developed human-like early CAVD lesion onlays. Extracellular matrix remodeling occurred in the absence of lipid deposition, macrophages, osteoblasts, or myofibroblasts, but with significant proteoglycan-rich onlays and chondrogenic cell presence. These early onlays were softer than the collagen-rich normal fibrosa, and their proteoglycan content was positively correlated with Sox9 chondrogenic expression, suggesting that soft proteoglycan-rich matrix may be permissive to chondrogenic VIC differentiation. The findings from this thesis shed new light on early disease pathogenesis and improve the fundamental understanding of aortic valve mechanics in health and disease.

Nesta dissertação, estudamos o efeito da Rosuvastatina (Ros) sob pacientes hipercolesterolêmicos. Dentro de 180 dias de estudo prospectivo, avaliamos a eficácia da utilização de anticorpos contra a LDL oxidada ou contra sequência peptídica da apolipoproteína B (apoBD) como marcadores no acompanhamento de resposta à droga. Acompanhamos 76 pacientes (Ros.,n=40/cont.,n=36) através das seguintes variáveis: perfil lipídico, TBARS, anticorpos IgG e IgM anti-oxLDL e IgG anti-apoBD. A partir dos resultados obtidos, concluímos que: não houve alterações consideradas significativas dentro do perfil lipídico; o tratamento controle reduziu significativamente TBARS; os anticorpos IgM anti-oxLDL e IgG anti-apoBD foram sensíveis como marcadores e houve redução significativa destes apenas no tratamento com Rosuvastatina; os níveis de anticorpos IgM e IgG anti-oxLDL não são correlacionados; existe correlação direta entre anticorpos IgG anti-oxLDL e anti-apoBD; os níveis de LDL se correlacionam inversamente aos níveis de IgG anti-oxLDL e IgG anti-apoBD. / In this dissertation, we studied the effect of rosuvastatin (Ros) in hypercholesterolemic patients. During 180 days, we evaluated t if antibodies against oxidized LDL or against a peptide from apolipoprotein B (apoBD) would work as markers to monitor a response to the drug. We enrolled 76 patients (Ros.,n = 40/cont.,n = 36 and used the following variables: lipid profile, TBARS, IgG and IgM anti-oxLDL and IgG anti-apoBD., We conclude that there were no significant changes seen in the lipid profile, the control treatment significantly reduced TBARS ,IgM anti-oxLDL and IgG anti-apoBD were sensitive markers and decreased significantly only in the treatment in Ros group; levels of IgM and IgG anti-oxLDL are not correlated; there is a direct correlation between IgG anti-oxLDL and anti-apoBD; LDL levels correlate inversely with levels of IgG anti-oxLDL and IgG anti-apoBD.

Introdução: Rosiglitazone (RGL) é um ligante dos receptores PPAR e vem sendo usada no tratamento do Diabetes Mellitus tipo 2 e nas doenças inflamatórias. Mas, RGL pode reduzir a filtração glomerular (FG), a carga excretada de sódio na urina (UVNa) e aumentar a expressão da Na+,K+- ATPase na medula renal. Então, RGL pode causar edema e insuficiência cardíaca congestiva. Entretanto, não tem sido reportado se RGL pode induzir insuficiência renal aguda (IRA). Objetivo: Verificar se a redução da FG causada pelo tratamento com RGL predispõe à IRA em ratos. Avaliar em condições basais e de vasoconstrição renal e se há diferenças entre ratos normocolesterolêmicos (NC) e hipercolesterolêmicos (HC). Métodos: A FG foi medida pelo clearance de inulina no 8º dia em ratos (~200g) NC e HC tratados ou não com RGL (48 mg/kg/dieta) na situação basal e durante a infusão endovenosa de Ang II (40 ng/kg/min). Além disso, a atividade da Na+,K+-ATPase foi avaliada em homogenato renal em outra série de animais. Resultados: Na situação basal, NC e HC apresentaram FG semelhante e o tratamento com RGL reduziu a FG apenas em NC de 0,78±0,03 para 0,50±0,05* ml/min/100g, *p<0,001. Apesar da redução da FG, a UVNa em NC+RGL não se modificou. Durante a infusão de Ang II, a FG de NC, HC e HC+RGL reduziu-se para o mesmo patamar de NC+RGL e um significante aumento da UVNa foi observada apenas em NC+RGL (NC= 3,32±0,88; NC+RGL=5,86±1,04*; HC= 2,63±0,43 e HC+RGL= 2,23±0,39 uEq/min, *p<0,01). Além disso, RGL induziu aumento na atividade da Na+,K+-ATPase em HC+RGL e não modificou em NC+RGL. Os valores expressos em M Pi/mg proteína.h-1 foram de 45±7 em NC, 43±5 em NC+RGL, 48±7 em HC e 64±4* em HC+RGL, *p<0,05. Analisando todos os resultados em conjunto, a redução da FG associada com a alta natriurese e ausência da modulação da atividade da Na+,K+-ATPase em NC+RGL sugerem lesão renal neste grupo. Conclusão: Os mecanismos de ação da RGL diferem de acordo com a condição metabólica. Então, RGL deve ser prescrita com cautela na ausência de hipercolesterolemia e requer a monitoração da função renal principalmente nas situações de vasoconstrição / Introduction: Rosiglitazone (RGL) is a ligand for PPAR used to treat type 2 Diabetes Mellitus and inflammatory diseases. However, RGL can reduce the glomerular filtration rate (GFR), urinary sodium excretion (UVNa) and increase the expression of Na+, K+-ATPase in renal medulla. Thus, RGL may induce edema and congestive heart failure. However, acute renal failure (ARF) provoked by RGL treatment has not been reported. Aim: To test whether reduced GFR by RGL may predispose to ARF at baseline and during a renal vasoconstriction state, and if the findings differ between normocholesterolemic (NC) and hypercholesterolemic (HC) rats. Methods: GFR was measured by inulin clearance on the 8th day in NC and HC rats (~200g) treated or not with RGL (48 mg/kg diet) at baseline and during intravenous infusion of Ang II (40 ng/kg/min). Furthermore, the Na+,K+- ATPase activity was determined in renal homogenates in other series of animals. Results: At baseline, NC and HC had similar GFR and the treatment with RGL reduced GFR only in NC from 0.78±0.03 to 0.50±0.05* ml/min/100g, *p<0.001. Although GFR was reduced, UVNa was unchanged in NC+RGL. During Ang II infusion, GFR was significantly reduced in NC, HC and HC+RGL and it remained at the same reduced level in NC+RGL. At this time, when GFR was reduced the same range in all groups, a significant increment in UVNa was only observed in NC+RGL (NC = 3.32±0.88; NC+RGL = 5.86±1.04*; HC = 2.63±0.43 and HC+RGL = 2.23±0.39 Eq/min, *p<0.01). Moreover, RGL induced an increase in the activity of Na+, K+-ATPase in HC+RGL, but it did not modify the activity of this enzyme in NC+RGL. The values expressed in M Pi/mg.protein.h-1 were 45±7 in NC, 43±5 in NC+RGL, 48±7 in HC and 64±4* in HC+RGL, *p<0.05. Taken together, reduction in GFR associated with high natriuresis and without changes in the Na+, K+-ATPase activity in renal medulla of NC+RGL may suggest renal injury in this group. Conclusion: RGL may act distinctly in normocholesterolemia and in hypercholesterolemia. Thus, RGL may be prescribed with caution in absence of hypercholesterolemia and requires monitoring of renal function specially if a renal vasoconstriction state is associated.

Introdução: Atualmente as Doenças Crônicas não Transmissíveis (DCNTs) são um dos maiores problemas de saúde pública da sociedade. É bastante claro o papel da dieta no controle do colesterol e na incidência de doenças cardiovasculares. Neste sentido, o amaranto desperta grande interesse devido a sua propriedade hipocolesterolemizante. Estudos sugerem que seu efeito hipocolesterolemizante está associado à inibição da enzima HMG-CoA redutase, chave na síntese do colesterol endógeno. Objetivo: Avaliar a atividade enzimática hepática da HMG-CoA redutase de hamsters alimentados com proteína de amaranto. Metodologia: Trinta hamsters foram divididos em 5 grupos e receberam dieta diferenciadas pela fonte protéica. Os grupos I e Icol receberam dieta com 20% de proteína de amaranto e os grupos caseína C e Ccol receberam dieta com 20% de caseína. Os grupos \"col\" apresentavam dieta com 0,1% de colesterol e 13,5% de gordura de coco. O metabolismo lipídico foi acompanhado através do monitoramento das concentrações plasmáticas de colesterol total, triacilgliceróis, HDL, e fração não-HDL nos animais. A excreção de colesterol e ácidos biliares foram quantificados nas fezes dos animais e o grau de esteatose hepática foi determinada através de análises histológicas do lobo direito do fígado. A atividade da enzima HMGR nos fígados foi medida por meio do Kit CS 1090 da Sigma-Aldrich com adaptações segundo Cong et al, 2012. A análise é baseada em espectrometria com absorbância de 340nm a 37ºC, que representa a oxidação de NADPH pela HMG-CoA redutase, na presença do substrato HMG-CoA. Conclusões: A proteína de amaranto pode ser considerado um aliado na redução dos agravos gerados pela dislipidemia, uma vez que reduziu significativamente os níveis de colesterol plasmático e gordura hepática, além de ser demonstrado seu efeito na redução da atividade da enzima HMG-CoA redutase dos animais hipercolesterolemizados que se alimentaram com proteína de amaranto. Uma vez verificado o efeito hipocolesterolemizante e seu possível mecanismo de ação por meio da enzima HMG-CoA redutase, espera-se com isso, estimular o consumo pela população brasileira produção de amaranto no Brasil, como alternativa para diversificar a dieta e a agricultura. / Introduction: Nowadays, Non-Communicable Chronic Diseases (NCCD) are a major challenge in health public. It is evident the role of diet in the control of cholesterol and incidence of cardiovascular disease. In this sense, amaranth arouses great interest due to its hypocholesterolemic property. Studies suggest that amaranth\'s hypocholesterolemic effect is associated with the inhibition of the enzyme HMG-CoA reductase, known as the key process to the endogenous cholesterol synthesis. Objective: Evaluate the hepatic enzymatic activity of HMG-CoA reductase in hamsters fed with amaranth protein. Methodology: Amaranth protein was isolated according to the conventional isoelectric precipitation methodology. Thirty hamsters were divided in 5 groups and were fed diets with different protein source. Experimental groups (I and lcol) had a diet containing 20% of protein amaranth and control groups(C and Cool) received a diet with 20% of casein. Moreover, groups \"col\" had also a diet with 0.1% cholesterol and 13.5% coconut oil in their composition. The lipid metabolism was accompanied through monitoring of plasma concentrations of total cholesterol, triglycerides, HDL and non-HDL fraction in animals. Excretion of cholesterol and bile acids were quantified in the feces of animals and the degree of hepatic steatosis was determined by histological analysis of the liver\'s right lobe. The HMGR enzyme activity in the liver was measured by the CS 1090 Kit from Sigma-Aldrich adjusted in accordance with Cong et al, 2012. The analysis is based on spectrometry with absorbance of 340nm at 37 ° C, which represents the oxidation of NADPH by HMG-CoA reductase in the presence of HMG-CoA substrate. Conclusions: Amaranth protein can be considered as an ally in reducing of injuries generated by dyslipidemia, since it significantly reduced levels of plasma cholesterol and hepatic fat. Furthermore, it was demonstrated its effect on reducing activity of HMG-CoA reductase enzyme in hypercholesterolemic animals, which were fed with amaranth protein. Therefore, once verified the hypocholesterolemic effect of amaranth and its possible action mechanism through HMG-CoA reductase enzyme, stimuli on the production of amaranth are expected as an alternative to diversify the diet and agriculture.

A obesidade na infância e adolescência tem aumentado de forma bastante acentuada, e quando observada nos primeiros anos de vida leva um maior risco para hipercolesterolemia, hipertrigliceridemia e alterações cardiovasculares na vida adulta. Uma correlação positiva tem sido observada entre a BMI (Body Mass Index, ou índice de massa corporal) e alterações metabólicas e hematológicas, implicando em alterações na capacidade de cicatrização, na defesa imunológica e celular e no desenvolvimento de diferentes patologias. O objetivo deste estudo foi avaliar os efeitos das fases iniciais da hipercolesterolemia, ou seja, nas idades infantil e juvenil e com pequeno aumento de colesterol, sobre os tecidos bucais e a capacidade de cicatrização. A Ratos Wistar (40g de peso) foi oferecido uma ração preparada com 1% de aumento (em peso) de colesterol + 20% de gordura (óleo de soja) por um período de 2 e 6 semanas para avaliação dos tecidos bucais. Após 2 semanas do uso da ração enriquecida com colesterol foram realizadas feridas cirúrgicas no dorso dos animais para avaliação da cicatrização. Ao final dos tratamentos propostos, os animais foram sacrificados, e colhidas as peças utilizadas (sangue, pele, língua, palatos e região gengival). O sangue coletado foi centrifugado e o soro foi utilizado para avaliação das lipoproteínas - colesterol total, HDL, LDL, VLDL e triglicérides em espectrofotômetro de absorbância. As peças colhidas foram levadas para fixação e descalcificação de acordo com a necessidade, processadas para inclusão em parafina, cortadas com 6 &micro;m de espessura, montadas em lâminas de vidro e coradas com hematoxilina e eosina. Essas peças foram utilizadas para avaliação histológica dos tecidos e do processo de cicatrização, por meio de técnicas morfométricas. Os dados colhidos foram apresentados em valores médios, e as diferenças analisadas por testes estatísticos adequados para a comparação entre as amostras. Nossos resultados mostram que a hipercolesterolemia provocou alterações em tecidos epiteliais e que esses efeitos parecem ser progressivos, ou seja, se tornam mais expressivos com o uso continuado de alimentação com índice de colesterol aumentado, e que existe um aparente atraso no processo de cicatrização nos indivíduos que utilizam dieta hipercolesterolêmica. Consideramos que essas alterações podem tornar esses indivíduos mais suscetíveis a alterações bucais e prejudicar as reações teciduais frente a injúrias, o que pode ser preocupante durante um tratamento odontológico, principalmente cirúrgico mas também em situações de reabilitação oral ou em tratamentos odontológicos de rotina. / Obesity in childhood has becoming a concern. Obesityy is associated with increased triglycerides, decreased high-density lipoprotein cholesterol levels, and increased low-density lipoprotein cholesterol and may lead to increased risk for hypercholesterolemia and cardiovascular complications in adult life. Clinical symptoms and signs of elevated cholesterol levels do not occur until adulthood, but subclinical aspects may be observed in children and adoslecentes. There are no studies on the effects of hypercholesterolemia in children, adolescents or in adults on oral tissues. We propose to study the influence of early age hypercolesterolemia in epithelial oral tissues and on wound healing. Male albino Wistar rats (40g) received enriched cholesterol diet (1%) for 2 and six weeks for epithelial evaluation. After 2 weeks, one control group (receiving standard pellet diet) and treated (hypercholesterolemic diet) received surgical wounds at the dorsum. Animals were sacrifed 1, 3 and 7 days after surgery. At the end of both periods (2 and 6 weeks) animals were sacrificed for epithelial evaluation. At the sacrifice time, serum were collected for evaluation of triglycerides, total cholesterol, HDL, LDL and VLDL. Were collected skin, tongue, palate and gingival tissues. Skin samples were also used for evaluation of the wound healing. All the observation were made at light microscopy. Data were statistically analysed by Mann Whitney U test for comparison between two samples. P[U] &le;0.05 were considered statistically significant. The enriched cholesterol diet significantly increased the total cholesterol, triglycerides, LDL and VLDL plasma content, and the study provide support for the hypothesis that hypercholesterolemia may be associated with deficiencies in the wound healing process. An important clinical implication of this study is the identification of alterations epithelium on oral tissues and in early phases of wound healing associated with subclinical but important alterations in cholesterol levels.

A hipercolesterolemia familiar (HF) é uma doença caracterizada por elevadas concentrações do colesterol das lipoproteínas de baixa densidade (LDL) e doença coronariana (DAC) prematura. Os remanescentes de quilomícrons são removidos principalmente pelo seu receptor específico (RLP), mas também pelo receptor da LDL. Este último encontra-se defeituoso na maior parte dos casos de HF e poderia levar a menor remoção plasmática dos quilomícrons. Há controvérsias se existem distúrbios do metabolismo dos quilomícrons em portadores de HF. Mais ainda não se sabe se estes defeitos poderiam contribuir para o desenvolvimento de DAC na HF. O objetivo deste estudo foi avaliar se portadores de HF apresentam defeitos na remoção plasmática de quilomícrons artificiais e seus remanescentes em relação a indivíduos normolipidêmicos. Foi avaliado também em estudo transversal se existe associação da cinética dos quilomícrons com a presença de DAC subclínica medida pela calcificação da artéria coronária (CAC). Foram estudados 36 pacientes portadores de HF e 50 controles normolipidêmicos pareados para idade e sexo. A remoção plasmática dos quilomícrons foi medida pelo decaimento radioisotópico da emulsão de quilomícrons artificiais injetada após jejum. A CAC foi determinada por tomografia computadorizada cardíaca nos portadores de HF. As taxas fracionais de remoção (TFR) dos quilomícrons e de seus remanescentes representadas pelo decaimento do 14C-éster de colesterol (TFR 14C-CE em min-1) foram menores nos portadores de HF em comparação aos normolipidêmicos: mediana (intervalos) 0,0013 (1,5.10-9;0,082) vs. 0,012 (1,51.10-9;0,017) p= 0,001. Não houve diferença em relação à remoção dos triglicérides da emulsão representada pelo decaimento da 3H-triglicérides (TFR 3H-TG em min-1) entre os grupos: 0,027 (0,0004;0,23) e 0,03 (0,0004;0,4) respectivamente nos grupo HF e controle (p= 0,26). Não foram encontradas diferenças significativas nas TFR tanto do 14C-CE 0,0007 (1,47. 10-9; 0,082) e 0,0013 (1,6. 10-9; 0,038) p= 0,67 como do 3H-TG 0,025 (0,0004; 0,07) e 0,0029 (0,009; 0,23), p=0,80 respectivamente nos portadores de HF apresentando (n=20) ou não CAC (n= 16). Em conclusão os portadores de HF apresentaram diminuição significativa da remoção dos quilomícrons e seus remanescentes em comparação com normolipidêmicos. Contudo, não foi encontrada associação entre esses distúrbios e a presença da DAC subclínica / Familial hypercholesterolemia (FH) is characterized by high concentrations of low density lipoproteins (LDL) cholesterol and early onset of coronary artery disease (CAD). Chylomicron remnants are removed mainly by their specific receptors (RLP) but also by the LDL receptor. The latter is defective in most cases of FH and could lead to lower plasma removal of chylomicrons and their remnants. There is controversy whether there are disorders of chylomicron metabolism in patients with FH. Moreover, it is unclear if these defects could contribute to the development of CAD in FH. The aim of this study was to evaluate whether there are defects on the removal from plasma of chylomicrons and their remnants in FH patients in comparison with normolipidemic subjects. We also evaluated in a cross sectional study the association of chylomicron kinetics with the presence of subclinical CAD represented by coronary artery calcification (CAC). We studied 36 patients with FH and 50 normolipidemic controls matched for age and sex. The plasma removal of chylomicrons was measured by isotopic decay of artificial chylomicron emulsion injected after fasting. CAC was determined by cardiac computed tomography in FH patients. The fractional catabolic rates (FCR) of chylomicrons and remnants removal represented by 14C-cholesteryl ester decay (14C-CE FCR in min-1) were lower in FH in comparison with normolipidemics: median (ranges) 0.0013 (1.47.10-9; 0.082) vs. 0.012 (1.51.10-9, 0.169) p = 0.001. There was no difference regarding the removal of emulsion triglyceride represented by 3H-triglyceride decay of ( 3H- TG FCR in min-1) between the groups: 0.026 (0.0004; 0.23) and 0.031 (0.0004; 0.4) respectively in FH and in normolipidemics (p = 0.264). There were no significant differences in both the 14C-CE FCR 0.0007 (1.47.10-9; 0.08) and 0.0013 (1.61.10-9; 0.038) p = 0.67 and in the 3H-TG FCR 0.025 (0.0004; 0.075) and 0.029 (0.0095; 0.23), p = 0.80 respectively in FH patients presenting (n = 20) or not CAC (n = 16). In conclusion patients with FH had a significant decrease on the removal from plasma of chylomicrons and their remnants compared with normolipidemics. However, no association between these disorders and the presence of CAC was found

Introdução: Atualmente as Doenças Crônicas não Transmissíveis (DCNTs) são um dos maiores problemas de saúde pública da sociedade. É bastante claro o papel da dieta no controle do colesterol e na incidência de doenças cardiovasculares. Neste sentido, o amaranto desperta grande interesse devido a sua propriedade hipocolesterolemizante. Estudos sugerem que seu efeito hipocolesterolemizante está associado à inibição da enzima HMG-CoA redutase, chave na síntese do colesterol endógeno. Objetivo: Avaliar a atividade enzimática hepática da HMG-CoA redutase de hamsters alimentados com proteína de amaranto. Metodologia: Trinta hamsters foram divididos em 5 grupos e receberam dieta diferenciadas pela fonte protéica. Os grupos I e Icol receberam dieta com 20% de proteína de amaranto e os grupos caseína C e Ccol receberam dieta com 20% de caseína. Os grupos \"col\" apresentavam dieta com 0,1% de colesterol e 13,5% de gordura de coco. O metabolismo lipídico foi acompanhado através do monitoramento das concentrações plasmáticas de colesterol total, triacilgliceróis, HDL, e fração não-HDL nos animais. A excreção de colesterol e ácidos biliares foram quantificados nas fezes dos animais e o grau de esteatose hepática foi determinada através de análises histológicas do lobo direito do fígado. A atividade da enzima HMGR nos fígados foi medida por meio do Kit CS 1090 da Sigma-Aldrich com adaptações segundo Cong et al, 2012. A análise é baseada em espectrometria com absorbância de 340nm a 37ºC, que representa a oxidação de NADPH pela HMG-CoA redutase, na presença do substrato HMG-CoA. Conclusões: A proteína de amaranto pode ser considerado um aliado na redução dos agravos gerados pela dislipidemia, uma vez que reduziu significativamente os níveis de colesterol plasmático e gordura hepática, além de ser demonstrado seu efeito na redução da atividade da enzima HMG-CoA redutase dos animais hipercolesterolemizados que se alimentaram com proteína de amaranto. Uma vez verificado o efeito hipocolesterolemizante e seu possível mecanismo de ação por meio da enzima HMG-CoA redutase, espera-se com isso, estimular o consumo pela população brasileira produção de amaranto no Brasil, como alternativa para diversificar a dieta e a agricultura. / Introduction: Nowadays, Non-Communicable Chronic Diseases (NCCD) are a major challenge in health public. It is evident the role of diet in the control of cholesterol and incidence of cardiovascular disease. In this sense, amaranth arouses great interest due to its hypocholesterolemic property. Studies suggest that amaranth\'s hypocholesterolemic effect is associated with the inhibition of the enzyme HMG-CoA reductase, known as the key process to the endogenous cholesterol synthesis. Objective: Evaluate the hepatic enzymatic activity of HMG-CoA reductase in hamsters fed with amaranth protein. Methodology: Amaranth protein was isolated according to the conventional isoelectric precipitation methodology. Thirty hamsters were divided in 5 groups and were fed diets with different protein source. Experimental groups (I and lcol) had a diet containing 20% of protein amaranth and control groups(C and Cool) received a diet with 20% of casein. Moreover, groups \"col\" had also a diet with 0.1% cholesterol and 13.5% coconut oil in their composition. The lipid metabolism was accompanied through monitoring of plasma concentrations of total cholesterol, triglycerides, HDL and non-HDL fraction in animals. Excretion of cholesterol and bile acids were quantified in the feces of animals and the degree of hepatic steatosis was determined by histological analysis of the liver\'s right lobe. The HMGR enzyme activity in the liver was measured by the CS 1090 Kit from Sigma-Aldrich adjusted in accordance with Cong et al, 2012. The analysis is based on spectrometry with absorbance of 340nm at 37 ° C, which represents the oxidation of NADPH by HMG-CoA reductase in the presence of HMG-CoA substrate. Conclusions: Amaranth protein can be considered as an ally in reducing of injuries generated by dyslipidemia, since it significantly reduced levels of plasma cholesterol and hepatic fat. Furthermore, it was demonstrated its effect on reducing activity of HMG-CoA reductase enzyme in hypercholesterolemic animals, which were fed with amaranth protein. Therefore, once verified the hypocholesterolemic effect of amaranth and its possible action mechanism through HMG-CoA reductase enzyme, stimuli on the production of amaranth are expected as an alternative to diversify the diet and agriculture.