Motivation: The prevalence of non-communicable diseases such as diabetes mellitus (DM) and cardiovascular disease (CVD) is rapidly increasing in industrialized societies. Experts believe that lifestyle, and in particular its nutritional aspects, plays a decisive role in increasing the burden of these chronic conditions. Dietary habits would, therefore, be modified to exert a positive impact on the prevention and treatment of chronic diseases of lifestyle. It is believed that the state of hyperglycaemia that is observed following food intake under certain dietary regimes contributes to the development of various metabolic conditions. This is not only true for individuals with poor glycaemic control such as some diabetics, but could also be true for healthy individuals. It would, therefore, be helpful to be able to reduce the amplitude and duration of postprandial hyperglycaemia. Selecting the correct type of carbohydrate (CHO) foods may produce less postprandial hyperglycaemia, representing a possible strategy in the prevention and treatment of chronic metabolic diseases. At the same time, a key focus of sport nutrition is the optimal amount of CHO that an athlete should consume and the optimal timing of consumption. The most important nutritional goals of the athlete are to prepare body CHO stores pre-exercise, provide energy during prolonged exercise and restore glycogen stores during the recovery period. The ultimate aim of these strategies is to maintain CHO availability to the muscle and central nervous system during prolonged moderate to high intensity exercise, since these are important factors in exercise capacity and performance. However, the type of CHO has been studied less often and with less attention to practical concerns than the amount of CHO. The glycaemic index (GI) refers to the blood glucose raising potential of CHO foods and, therefore, influences secretion of insulin. In several metabolic disorders, secretion of insulin is inadequate or impossible, leading to poor glycaemic control. It has been suggested that low GI diets could potentially contribute to a significant improvement of the conditions associated with poor glycaemic control. Insulin secretion is also important to athletes since the rate of glycogen synthesis depends on insulin due to it stimulatory effect on the activity of glycogen synthase. Objectives: Three main objectives were identified for this study. The first was to conduct a meta-analysis of the effects of the GI on markers for CHO and lipid metabolism with the emphasis on randomised controlled trials (RCT's). Secondly, a systematic review was performed to determine the strength of the body of scientific evidence from epidemiological studies combined with RCT's to encourage dieticians to incorporate the GI concept in meal planning. Finally, a systematic review of the effect of the GI in sport performance was conducted on all available literature up to date to investigate whether the application of the GI in an athlete's diet can enhance physical performance. Methodology: For the meta-analysis, the search was for randomised controlled trials with a cross-over or parallel design published in English between 1981 and 2003, investigating the effect of low GI vs high GI diets on markers of carbohydrate and lipid metabolism. The main outcomes were serum fructosamine, glycosylated haemoglobin (HbA1c), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), total cholesterol (TC) and triacylglycerols (TG). For the systematic review, epidemiological studies as well as RCT's investigating the effect of LGI vs HGI diets on markers for carbohydrate and lipid metabolism were used. For the systematic review on the effect of the GI on sport performance, RCT's with either a cross-over or parallel design that were published in English between January 1981 and September 2004 were used. All relevant manuscripts for the systematic reviews as well as meta-analysis were obtained through a literature search on relevant databases such as the Cochrane Central Register of Controlled Trials, MEDLINE (1981 to present), EMBASE, LILACS, SPORTDiscus, ScienceDirect and PubMed. This thesis is presented in the article format. Results and conclusions of the individual manuscripts: For the meta-analysis, literature searches identified 16 studies that met the strict inclusion criteria. Low GI diets significantly reduced fructosamine (p<0.05), HbA1c, (p<0.03), TC(p<0.0001) and tended to reduce LDL-c (p=0.06) compared to high GI diets. No changes were observed in HDL-c and TG concentrations. Results from this meta analysis, therefore, support the use of the GI concept in choosing CHO-containing foods to reduce TC and improve blood glucose control in diabetics. The systematic review combined the results of the preceding meta-analysis and results from epidemiological studies. Prospective epidemiological studies showed improvements in HDL-c concentrations over longer time periods with low GI diets vs. high GI diets, while the RCT's failed to show an improvement in HDL-c over the short-term. This could be attributed to the short intervention period during which the RCT's were conducted. Furthermore, epidemiological studies failed to show positive relationships between LDL-c and TC and low GI diets, while RCT's reported positive results on both these lipids with low GI diets. However, the epidemiological studies, as well as the RCT's showed positive results with low GI diets on markers of CHO metabolism. Taken together, convincing evidence from RCT's as well as epidemiological studies exists to recommend the use of low GI diets to improve markers of CHO as well as of lipid metabolism. 3 From the systematic review regarding the GI and sport performance it does not seem that low GI pre-exercise meals provide any advantages over high GI pre-exercise meals. Although low GI pre-exercise meals may better maintain CHO availability during exercise, low GI pre-exercise meals offer no added advantage over high GI meals regarding performance. Furthermore, the exaggerated metabolic responses from high GI compared to low GI CHO seems not be detrimental to exercise performance. However, athletes who experience hypoglycaemia when consuming CHO-rich feedings in the hour prior to exercise are advised to rather consume low GI pre-exercise meals. No studies have been reported on the GI during exercise. Current evidence suggests a combination of CHO with differing Gl's such as glucose (high GI), sucrose (moderate GI) and fructose (low GI) will deliver the best results in terms of exogenous CHO oxidation due to different transport mechanisms. Although no studies are conducted on the effect of the GI on short-term recovery it is speculated that high GI CHO is most effective when the recovery period is between 0-8 hours, however, evidence suggests that when the recovery period is longer (20-24 hours), the total amount of CHO is more important than the type of CHO. Conclusion: There is an important body of evidence in support of a therapeutic and preventative potential of low GI diets to improve markers for CHO and lipid metabolism. By substituting high GI CHO-rich with low GI CHO-rich foods improved overall metabolic control. In addition, these diets reduced TC, tended to improve LDL-c and might have a positive effect over the long term on HDL-c. This confirms the place for low GI diets in disease prevention and management, particularly in populations characterised by already high incidences of insulin resistance, glucose intolerance and abnormal lipid levels. For athletes it seems that low GI pre-exercise meals do not provide any advantage regarding performance over high GI pre-exercise meals. However, low GI meals can be recommended to athletes who are prone to develop hypoglycaemia after a CHO-rich meal in the hour prior to exercise. No studies have been reported on the effect of the GI during exercise. However, it has been speculated that a combination of CHO with varying Gl's deliver the best results in terms of exogenous CHO oxidation. No studies exist investigating the effect of the GI on short-term recovery, however, it is speculated that high GI CHO-rich foods are suitable when the recovery period is short (0-8 h), while the total amount rather than the type of CHO is important when the recovery period is longer (20-24 h). Therefore, the GI is a scientifically based tool to enable the selection of CHO-containing foods to improve markers for CHO and lipid metabolism as well as to help athletes to prepare optimally for competitions. Recommendations: Although a step nearer has been taken to confirm a place for the GI in human health, additional randomised, controlled, medium and long-term studies as well as more epidemiological studies are needed to investigate further the effect of low GI diets on LDL-c. HDL-c and TG. These studies are essential to investigate the effect of low GI diets on endpoints such as CVD and DM. This will also show whether low GI diets can reduce the risk of diabetic complications such as neuropathy and nephropathy. Furthermore, the public at large must be educated about the usefulness and application of the GI in meal planning. For sport nutrition, randomised controlled trials should be performed to investigate the role of the GI during exercise as well as in sports of longer duration such as cricket and tennis. More studies are needed to elucidate the short-term effect of the GI post-exercise as well as to determine the mechanism of lower glycogen storage with LGI meals post-exercise. / Thesis (Ph.D. (Dietetics))--North-West University, Potchefstroom Campus, 2005.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Atherosclerosis is a chronic inflammatory disease that is characterized by the accumulation of lipids and fibrous elements in the intima layer of arteries of medium and large caliber. The cardiovascular diseases resulting from atherosclerosis, among them acute myocardial infarction and stroke are the leading cause of mortality and morbidity worldwide. Oxidative stress and oxidative modification of low density lipoprotein (LDL) have an important role in the development of this disease and so the inclusion of antioxidants in the diet may prevent the progression of atherosclerosis. The carotenoid norbixin (NBX), which is found in annatto seeds, have excellent antioxidant activity as demonstrated in several models of oxidative damage. In this context, the objective of this study was to evaluate the antioxidant, anti-inflammatory and antiatherogenic potential of NBX in a model of atherosclerosis in rabbits. Male New Zealand rabbits received regular chow (control) or an atherogenic diet (0.5% cholesterol) alone or supplemented with NBX (10, 30 or 100 mg/kg) for 60 days. The antioxidant enzyme activities, lipid profiles, oxidative stress and inflammatory markers and histopathological status were evaluated in the serum or aortic tissue. The atherogenic diet increased serum lipids, oxidized low-density lipoprotein (LDLox) levels and oxidized low-density lipoprotein antibody (LDLoxAB) levels, in addition to inducing lipid and protein oxidation in the aortic tissue. Supplementation with NBX caused 35% reduction in the levels of LDLoxAB, 69% in the levels of LDLox, 27% in the levels of TBARS and 46% in the levels of protein carbonyl induced by the atherogenic diet, besides increasing up to 88% the HDL levels. In atherosclerotic rabbits, the non-protein thiol group content and enzymatic activity of the antioxidants superoxide dismutase, catalase, glutathione reductase and thioredoxin reductase were increased in aortic tissue, whereas paraoxonase activity was reduced in serum. Supplementation with NBX restored up to 41% the increased levels of NPSH, 37% SOD activity, 45% CAT activity, 66% GR activity, 50% TrxR-1 activity induced by the atherogenic diet. NBX also restored 15% of PON1 activity inhibited by the atherogenic diet. The atherogenic diet also increased the serum levels of inflammatory markers and the ratio of the intima area to the media area in the aortic arch; these changes were not prevented by NBX. Thus, NBX supplementation improved the lipid profile, decreased oxidative stress and prevented changes in paraoxonase activity and in the antioxidant system in hypercholesterolemic rabbits, but did not prevent the formation of atherosclerotic plaques. These results support a beneficial role of NBX in the treatment of atherosclerosis by preventing oxidative events and by restoring antioxidant enzyme activity and paraoxonase activity. / A aterosclerose é uma doença inflamatória crônica caracterizada pelo acúmulo de lipídeos e elementos fibrosos na túnica intima das artérias de médio e grande calibre. As doenças cardiovasculares decorrentes da aterosclerose, dentre elas o infarto agudo do miocárdio e o acidente vascular cerebral são a principal causa de mortalidade e morbidade mundial. O estresse oxidativo e a modificação oxidativa da lipoproteína de baixa densidade (LDL) possuem um papel importante no desenvolvimento dessa doença. Por este motivo a inclusão de antioxidantes na dieta poderia impedir a progressão da aterosclerose. O carotenóide norbixina (NBX), presente nas sementes de urucum, possui excelente atividade antioxidante já demonstrada em diversos modelos de dano oxidativo. Nesse contexto, o objetivo deste trabalho foi avaliar o potencial antioxidante, anti-inflamatório e antiaterogênico da NBX em um modelo de aterosclerose em coelhos. Coelhos Nova Zelândia machos receberam ração regular (controle) ou uma dieta aterogênica (0,5% de colesterol) sozinha ou suplementada com NBX (10, 30 ou 100 mg/kg) por 60 dias. A atividade das enzimas antioxidantes, o perfil lipídico, os marcadores de estresse oxidativo e inflamação e as alterações histopatológicas foram avaliados no soro ou tecido aórtico dos coelhos hipercolesterolêmicos. A dieta aterogênica aumentou os níveis séricos de lipídios, de lipoproteína de baixa densidade oxidada (LDLox) e de anticorpos contra lipoproteína de baixa densidade oxidada (LDLoxAB), além de induzir a oxidação de lipídios e proteína no tecido aórtico. A suplementação com NBX reduziu em até 35% o aumento dos níveis de LDLoxAB, 69% dos níveis de LDLox, 27% dos níveis de TBARS e 46% dos níveis de proteínas carboniladas induzidos pela dieta aterogênica, além de aumentar em até 88% os níveis de HDL. Nos coelhos ateroscleróticos ocorreu uma elevação no conteúdo de grupos tiólicos não-protéicos (NPSH) e na atividade das enzimas antioxidantes superóxido dismutase (SOD), catalase (CAT), glutationa redutase (GR) e tioredoxina redutase (TrxR-1) no tecido aórtico, enquanto a atividade da enzima paraoxonase (PON1) foi reduzida no soro. A suplementação com NBX reduziu em até 41% o aumento dos níveis de NPSH, 37% da atividade da SOD, 45% da atividade da CAT, 66% da atividade da GR e 50% da atividade da TrxR-1 induzidos pela dieta aterogênica. A NBX também restaurou em 15% a atividade da PON1 inibida pela dieta aterogênica. A dieta aterogênica também aumentou os níveis séricos de marcadores inflamatórios e a relação entre a área da íntima e da média no arco aórtico e essas mudanças não foram prevenidas pela NBX. Assim, a suplementação com NBX melhorou o perfil lipídico, diminuiu o estresse oxidativo e impediu mudanças na atividade da paraoxonase e no sistema antioxidante em coelhos hipercolesterolêmicos, mas não impediu a formação de placas ateroscleróticas. Esses resultados indicam um papel benéfico da NBX no tratamento de aterosclerose, impedindo eventos oxidativo e restaurando a atividade das enzimas antioxidantes e da enzima paraoxonase.

As doenças cardiovasculares são a principal causa de mortalidade no mundo. A aterosclerose é a base fisiopatológica dessas doenças, sendo definida como um processo crônico-inflamatório multifatorial, resultando da interação de diferentes células como linfócitos, macrófagos, células endoteliais e células musculares lisas na parede arterial. A lipoproteína de baixa densidade eletronegativa [LDL(-)], uma subfração modificada da LDL nativa, desempenha um papel-chave na aterosclerose, uma vez que as modificações sofridas por esta partícula são capazes de induzir o acúmulo de ésteres de colesterol em macrófagos e a subsequente formação de células espumosas. O sistema imunológico é crucial no processo aterogênico e estratégias terapêuticas direcionadas à imunoregulação deste processo têm sido utilizadas como novas alternativas tanto na prevenção do desenvolvimento quanto da progressão desta doença. Dentre essas estratégias, destaca-se o uso de fragmentos de anticorpos como o scFv (do inglês, single chain fragment variable), que podem ainda estar conjugados a nanopartículas com o intuito de aumentar sua eficiência de ação no organismo. Diante do papel da LDL(-) na aterosclerose, este projeto objetivou avaliar os efeitos in vitro e in vivo de um sistema nanoestruturado contendo fragmentos scFv anti-LDL(-) derivatizados na superfície de nanocápsulas sobre macrófagos murinos e humanos primários e em camundongos knockout para o gene do receptor da LDL (Ldlr-/-) no desenvolvimento e na progressão dessa doença. Demonstrou-se que o tratamento de macrófagos com a formulação scFv anti-LDL(-)-MCMN-Zn diminuiu de forma significativa a captação de LDL(-), assim como a expressão de IL-1&#946; (mRNA e proteína) e MCP-1 (mRNA). Foi demonstrada a internalização da nanoformulação pelos macrófagos via diferentes mecanismos de endocitose, demonstrando seu potencial uso como carreador de fármacos. In vivo, a nanoformulação diminuiu de forma significativa a área da lesão aterosclerótica em camundongos Ldlr-/- submetidos à avaliação pela técnica de tomografia por emissão de pósitrons (do inglês, PET), utilizando o radiotraçador 18F-FDG (18F-desoxiglicose), associada à tomografia computadorizada (CT) com agente de contraste iodado, além da análise morfométrica das lesões no arco aórtico. O conjunto dos resultados obtidos evidenciou a ação ateroprotetora da formulação scFv anti-LDL(-)-MCMN-Zn, reforçando seu potencial como estratégia terapêutica na aterosclerose. / Cardiovascular diseases are the leading cause of mortality worldwide. Atherosclerosis is the pathophysiological basis of these diseases, defined as a chronic inflammatory multifactorial process, resulting from the interaction of several cells such as lymphocytes macrophages, endothelial cells and smooth muscle cells within the arterial wall. The electronegative low-density lipoprotein [LDL(-)], a modified subfraction of native LDL, plays a key role in atherosclerosis, since its modifications are capable of inducing the accumulation of cholesteryl esters in macrophages and the subsequent foam cells formation. The immune system is crucial in atherogenic process and therapeutic strategies directed to the immunoregulation of this process have been used as a new alternative in the prevention of the development as well as the progression of this disease. Among these strategies, it is the use of antibody fragments such as scFv (single chain fragment variable), which may be also conjugated to nanoparticles in order to increase their efficiency in the body. Given the role of LDL(-) in atherosclerosis, the aim of this project was to evaluate the in vitro and in vivo effects of a nanostructured system containing scFv anti-LDL(-) fragments derivatized on the surface of nanocapsules on murine and human primary macrophages and in the development and progression of the disease in LDL receptor knockout mice (Ldlr-/-). It was demonstrated that the treatment of macrophages with scFv anti-LDL(-)-MCMN-Zn formulation significantly decreases the uptake of LDL(-) and the expression IL-1&#946; (mRNA and protein) and MCP-1 (mRNA). Moreover, the internalization of the nanoformulation by macrophages through different endocytosis mechanisms was shown, demonstrating its potential use as a nanocarrier. In vivo, the nanoformulation decreased the area of atherosclerotic lesions in Ldlr-/- mice evaluated by positron emission tomography with 18F-FDG associated with computed tomography with iodinated contrast agent (PET/CT), besides the lesion morphometric analysis at the aortic arch Thus, these data provide evidence of the atheroprotection action of the ateroprotection action of the scFv anti-LDL(-)-MCMN-Zn formulation, suggesting its promising use as a therapeutic strategy for atherosclerosis.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Abnormalities of lipid metabolism often lead to pathologic lipid accumulation in the vessel wall, oxidative and chronic inflammatory sequelae and the formation of atherosclerotic lesions, ultimately leading to clinical events. Low density lipoprotein (LDL) oxidative modification in the vascular wall seems to be a key factor in atherosclerosis development. Following the oxidation hypothesis of atherosclerosis the role of antioxidants has been investigated in a large number of epidemiological, clinical and experimental studies. Therefore, we investigated the antioxidant activity of three compounds of different classes in preventing the low density lipoprotein oxidation. In the guaraná study, we showed that subjects who habitually ingested guaraná (GI) demonstrated lower conjugated dienes production than did subjects who never ingested guaraná (NG; reduction of 27%, p < 0,0014), independent of other variables. However, in the GI group the conjugated dienes production was positively associated with glucose levels. The GI group also showed a total cholesterol level significantly lower than NG group. Also, guaraná demonstrated a high antioxidant activity in vitro, mainly at concentrations of 1 and 5 μg/mL, demonstrated by suppression of CDs and TBARS productions, tryptophan destruction and high TRAP activity. Guaraná, similar to other foods rich in caffeine and catechins such as green tea, has some effect on LDL oxidation that could partially explain the protective effects of this food in cardiometabolic diseases. In the thiosemicarbazone study, salicylaldehyde-4- phenylthiosemicarbazone (SPTS) may have antioxidant activity against Cu2+- and 2,2′- Azobis(2-methylpropionamidine) dihydrochloride (AAPH)-induced LDL and serum oxidation. Additionally, SPTS was effective at preventing tryptophan destruction. SPTS also showed significant total radical-trapping antioxidant activity and could prevent thiobarbituric acid reactive substances (TBARS) formation induced by sodium nitroprusside in different rat tissues and by Cu2+ in human LDL and serum. These results indicate that the antioxidant effect of SPTS is caused by a combination of transition metal chelation and free-radicalscavenging activity. In the organotellurium study, the 2-phenyl-2-tellurophenyl vinylphosphonate (DPTVP) may have antioxidant activity against Cu2+- and 2,2′-azobis(2- methylpropionamidine) dihydrochloride (AAPH)-induced LDL and serum oxidation. Additionally, DPTVP was effective at preventing tryptophan oxidation. DPTVP also showed significant total radical-trapping antioxidant activity and could prevent thiobarbituric acid reactive substance (TBARS) formation induced by Cu2+ in human LDL and serum. Additionally, DPTVP exhibited no toxicity in rat aorta slices. The results presented here indicate that the antioxidant effect of DPTVP is caused by a combination of free-radicalscavenging activity and possible blockade of the copper binding sites of LDL. Considering these preliminary results, we can conclude that the three compounds presented a potential antioxidant activity and could prevent the oxidative modifications of LDL. These data encourage us to evaluate these compounds in in vivo studies and investigate additional properties in preventing the atherogenic process. / Anormalidades do metabolismo lipídico muitas vezes levam ao acúmulo patológico de lipídios na parede arterial, sequelas oxidativas e inflamatórias crônicas e à formação de lesões ateroscleróticas, levando a eventos clínicos. A modificação oxidativa de lipoproteínas de baixa densidade (LDL) na parede arterial parece ser um fator importante no desenvolvimento da aterosclerose. Seguindo a hipótese oxidativa da aterosclerose, o papel dos antioxidantes tem sido investigado em grande número de estudos epidemiológicos, clínicos e experimentais. Sendo assim, neste estudo nós investigamos a atividade antioxidante de três compostos de diferentes classes na prevenção da oxidação da LDL. No estudo com guaraná, nós mostramos que indivíduos que consumiam guaraná habitualmente (GI) apresentaram menor produção de dienos conjugados que os indivíduos que nunca consumiam guaraná (NG; redução de 27%, p < 0,0014), independentemente de outras variáveis. No entanto, no grupo GI a produção de dienos conjugados foi positivamente associada com os níveis de glicose. O grupo GI também apresentou nível de colesterol total significativamente menor comparado ao grupo NG. Além disso, o guaraná apresentou uma grande atividade antioxidante in vitro, principalmente nas concentrações de 1 e 5 μg/mL, demonstrado pela supressão da produção de dienos conjugados e substâncias reativas ao ácido tiobarbitúrico, prevenção da destruição do triptofano e alta atividade scavenger de radicais (TRAP). O guaraná, similar a outros alimentos ricos em cafeína e catequinas como o chá verde, tem alguns efeitos na oxidação da LDL que podem explicar parcialmente os efeitos protetores deste alimento nas doenças cardiometabólicas. No estudo com a tiosemicarbazona, a salicilaldeído-4-feniltiosemicarbazona (SPTS) apresentou atividade antioxidante contra a oxidação de LDL e soro induzidas por Cu2+ e 2,2 -azobis(2- metilpropionamidina) dihidrocloreto (AAPH). Além disso, a SPTS foi efetiva em prevenir a destruição do triptofano. O composto também apresentou significativa atividade scavenger de radicais e pode prevenir a formação de substâncias reativas ao ácido tiobarbitúrico induzidas por nitroprussiato de sódio em diferentes tecidos de ratos e por Cu2+ em LDL e soro humano. Estes resultados indicam que o efeito antioxidante da SPTS é causado pela combinação da atividade quelante do composto e a atividade scavenger de radicais livres. No estudo com o composto orgânico de telúrio, o 2-fenil-2-telurofenil vinilfosfonato (DPTVP) apresentou atividade antioxidante contra a oxidação de LDL e soro humano induzida por AAPH e Cu2+. Além disso, o composto preveniu a oxidação do triptofano e a formação de substâncias reativas ao ácido tiobarbitúrico e mostrou um significativo efeito scavenger de radicais. O DPTVP (20 μM) não apresentou toxicidade quando exposto à fatias de aorta de ratos. Estes resultados indicam que o efeito do DPTVP é resultado de uma combinação da atividade scavenger de radicais do composto e da possibilidade dele bloquear os sítios de ligação de cobre da LDL. Considerando todos os resultados apresentados aqui, podemos concluir que os três compostos apresentam um grande potencial antioxidante e podem prevenir as modificações oxidativas da LDL. Esses dados nos encorajam para avaliar esses compostos em estudos in vivo e investigar novas propriedades que possam prevenir o processo aterogênico.

Atherosclerosis is an arterial disease that occurs due to the build-up of lipids, cholesterol and other substances in the arterial wall, collectively called plaque, leading to narrowing of the vessel lumen and, in time, disruption to the blood supply. The study of flow through atherosclerotic vessels is especially important since plaques not only cause a reduction in the vessel lumen but can rupture from the arterial wall, causing a blood clot in the vessel that may ultimately lead to heart attack or a stroke. Elevated level of oxidated low density lipoprotein (LDL) is a known risk factor associated with the genesis of atherosclerosis in arterial walls. Previous studies reported in literature have explored the transport of LDL through the arterial wall using analytical and mathematical models. In this work, we have presented a computational framework for the study of LDL transport in the lumen and the porous arterial wall. We have employed a four-layer arterial wall model and used governing equations to model the transport of LDL. We have used physiological parameters for the wall layers from literature and have validated the model based on the calculated filtration velocities and LDL concentration profiles in the arterial wall. We have further used this established model to study the effect of change in permeability and pressure on the LDL concentration. We have also studied the effect of pulsatile flow on the transport of LDL through the porous walls to examine the validity of the initial assumption of steady state and have seen that pulsation increases the time averaged net flux of LDL species by about 20%. We have next modeled a drug-eluting stent (DES), which is one of the popular remedies to cure atherosclerosis. The validation of DES model is followed by a combined study to analyze the effect of stent placement on LDL transport. Although there is no chemical reaction between the drug and LDL, we have noticed recirculation zones near the stent strut which result in accumulation of LDL molecules in the arterial wall. Future studies are aimed at incorporating variable porosity and permeability and a stenosed region in the geometry. The deformation of arterial wall due to pulsatile blood flow may lead to alteration of wall properties, which can give a realistic view of macromolecular transport.

Introdução: A Hipercolesterolemia Familiar (HF) é uma doença genética caracterizada clinicamente por elevados níveis de lipoproteína de baixa densidade (LDL-C) na corrente sanguínea desde a infância. Indivíduos que apresentam HF podem desenvolver doença aterosclerótica ainda em idade jovem. Os principais preditores de risco no desenvolvimento da doença cardiovascular (DCV) nesses indivíduos após entrarem em um programa de rastreamento genético não são conhecidos na nossa população. Além disso, a HF é subdiagnosticada e subtratada mundialmente e o rastreamento genético em cascata dos familiares tem sido mundialmente avaliado como o método diagnóstico mais custo. Contudo, a efetividade do rastreamento genético em cascata é dependente dos critérios clínicos de entrada do primeiro indivíduo da família e não há um consenso de qual critério apresenta a melhor acurácia para detecção de uma mutação. Objetivos: Identificar os fatores determinantes para ocorrência de eventos cardiovasculares (CV) em todos os indivíduos da coorte e avaliar o critério clínico para detecção de uma variante genética patogênica para HF, no primeiro indivíduo da família, após serem inseridos em um programa de rastreamento genético em cascata.Métodos: Estudo de coorte prospectiva aberta dos pacientes que foram inseridos no programa de rastreamento genético em cascata para HF. A população do estudo é definida como caso índice (CI), o primeiro da família a ser identificado clinicamente e encaminhado para o teste genético, e os familiares, que são os parentes de 1º grau do CI em que foi encontrada uma alteração genética. Todos os indivíduos são inseridos na coorte no momento em que recebem o laudo genético (tempo zero, T0). Um ano depois do T0 é realizado o primeiro contato telefônico, ou seja, primeiro ano de seguimento (T1) Resultados: No T1, o total de 818 indivíduos foi incluído, sendo verificados 47 eventos CV, sendo 14 (29,7%) fatais. Para o CI, o único fator independente associado ao aumento do risco de eventos CV no T1 foi a presença de arco corneano (OR: 9,39; IC 95%: 2,46-35,82). Para os familiares com uma mutação positiva os fatores associados ao aumento do risco de eventos CV foram diabetes mellitus (OR: 7,97; IC 95%: 2,07-30,66) e consumo de tabaco (OR: 3,70; IC 95%: 1,09-12,50). Na análise do melhor critério clínico para detecção de uma mutação patogênica no CI os valores de LDL-C >= 230 mg/dL tiveram a melhor relação entre sensibilidade e especificidade. Na análise da curva ROC o escore Dutch Lipid Clinic Network (DLCN) apresentou melhor desempenho do que o LDL-C para identificar uma mutação, a área sob a curva ROC foi 0,744 (IC 95%: 0,704-0,784) e 0,730 (IC 95%: 0,687-0,774), respectivamente, p = 0, 014. Conclusão: Em um ano de seguimento essa coorte identificou uma alta incidência de eventos CV após a entrada em um programa de rastreamento genético em cascata e os preditores dos eventos CV diferem entre CI e familiares. Esses resultados podem contribuir para o desenvolvimento de ações preventivas nesse grupo altamente susceptível de indivíduos. Além disso, devido a importância da detecção da mutação para um diagnóstico definitivo de HF e a importância da cascata ser custo efetiva o estudo identificou que o critério único do LDL-C >= 230 mg/dl é viável para indicar o CI para o teste genético / Introduction: Familial Hypercholesterolemia (FH) is a genetic disease characterized clinically by high levels of low density lipoprotein (LDL-C) in the bloodstream since childhood. Individuals with FH can develop atherosclerotic disease at a young age. The main predictors of cardiovascular disease (CVD) risk in these individuals after entering a genetic screening program are not known in our population. In addition, FH is underdiagnosed and undertreated worldwide and cascaded genetic screening of family members has been evaluated globally as the most cost effective for the diagnosis of FH. However, the effectiveness of cascading genetic screening is dependent on the clinical entry criteria of the first individual in the family and there is no consensus as to which criterion shows the best accuracy for detecting a mutation. Objectives: To identify the determinant factors for cardiovascular (CV) events in all individuals in the cohort and to evaluate the clinical criteria for detecting a genetic variant pathogenic to FH in the first individual of the family after being inserted into a genetic screening program in cascade. Methods: Open prospective cohort study of patients who were enrolled in the cascade genetic screening program for FH. The study population is defined as index case (IC), the first of the family to be clinically identified and referred to the genetic test, and relatives, who are the first-degree relatives of the IC in which a genetic alteration was found. All individuals are inserted into the cohort at the moment they receive the genetic report (time zero, T0). The first follow-up telephone contact is made one year after T0 (first year of follow-up, T1). Results: In T1, a total of 818 subjects were included, and 47 CV events were verified, of which 14 (29.7%) were fatal. For IC, the only factor independently associated with the increased risk of CV events in T1 was the presence of a corneal arch (OR: 9.39; 95% CI: 2.46-35.82). For relatives with positive mutation, factors associated with increased risk of CV events were diabetes mellitus (OR: 7.97; 95% CI: 2.07-30.66) and tobacco consumption (OR: 3.70; 95% CI: 1.09-12.50). In the analysis of the best clinical criteria for the detection of a pathogenic mutation in the IC, the LDL-C values >= 230 mg/dL had the best relationship between sensitivity and specificity. In the ROC curve analysis, the Dutch Lipid Clinic Network (DLCN) score performed better than LDL-C to identify a mutation, the area under the ROC curve was 0.744 (95% CI: 0.704-0.784) and 0.730 (CI 95 %: 0.687-0.774), respectively, p = 0.014. Conclusion: At one year follow-up this cohort identified a high incidence of CV events following entry into a cascade genetic screening program and the predictors of CV events differ between IC and family members. These results may contribute to the development of preventive actions in this group highly susceptible to individuals. In addition, because of the importance of detecting the mutation for a definitive diagnosis of HF and the importance of the cascade being cost effective, the study identified that the single LDL-C criterion >= 230 mg / dl is feasible to indicate IC for the genetic test

Magister Pharmaceuticae - MPharm / Cardiovascular diseases (CVDs) such as ischaemic heart diseases, heart failure and stroke remain a major cause of death globally. Various deep-rooted factors influence CVD development; these include but are not limited to elevated blood lipids, high blood pressure, obesity and diabetes. A considerable number of proteins are involved directly and indirectly in the transport, maintenance and elimination of plasma lipids, including high and low-density lipoprotein cholesterol (HDL-C and LDL-C). There are several mechanisms involved in the removal of LDL particles from systemic circulation. One such mechanism is associated with the gene that encodes proprotein convertase subtilisin/kexin type 9 (PCSK9), which has become an exciting therapeutic target for the reduction of residual risk of CVDs. Currently, statins are the mainstay treatment to reduce LDL-C, and a need exists to further develop more effective LDL-C-lowering drugs that might supplement statins. This study was aimed at contributing to the generation of knowledge regarding the effect of niacin in reducing LDL levels through PCSK9 interaction. The aims/objectives of this study were achieved by utilizing two approaches, which included animal intervention with niacin followed by genetic screening of five prioritized genes involved in cholesterol synthesis and regulation. For animal intervention, 16 vervet monkeys were divided into two groups of eight animals consisting of a control and an experimental (niacin) group. The control group was given a normal standard diet of pre-cooked maize meal throughout the study, while the experimental group received the same diet supplemented with 100 mg/kg of niacin (SR) for 12 weeks. During the niacin intervention, blood was collected at baseline, every four weeks during the treatment period and the end of the washout period. The collected blood was used for biochemical analysis (total cholesterol, triglycerides, LDL-C, and HDL-C) and downstream genetic applications. The second phase included the screening of PCSK9, LDLR, SREBP-2, CETP and APOB-100 using genotyping and gene expression. Niacin administration produced statistically significant increases in plasma HDL-C at fourtime points (T1, T2, T3 and T4), which resulted in an overall increase in plasma HDL-C. Additionally, niacin administration resulted in a slight reduction in LDL-C and total cholesterol levels. Furthermore, the genotyping analysis revealed 13 sequence variants identified in PCSK9, LDLR, SREBP-2, CETP and APOB-100 genes. Five of these variants were predicted to be disease-causing and correlated with gene expression patterns. Three identified PCSK9 variants (H177N, R148S, G635G) were categorized as LOF mutations, and this was supported by a decline in gene expression in animals harbouring these variants. The LDLR also had LOF variants that were the reason for its decreased mRNA expression. Additionally, SREBP-2 proved to be a key mediator of cholesterol pathways. Therefore, the findings of the study conclusively suggest that niacin does increase HDL-C and decrease LDL-C and total cholesterol. Moreover, an interaction between niacin administration and PCSK9 was observed which resulted in decreased gene expression.

Background: This study was conducted to test the hypothesis that internal medicine residents at a northeast Tennessee university clinic were not compliant with the latest National Cholesterol Educational Program Adult Treatment Panel (NCEP-ATP) guidelines in treating hyperlipidemia in patients with diabetes and coronary artery disease. Methods: A retrospective medical record survey was conducted to evaluate residents' pattern in lowering low-density lipoprotein (LDL) cholesterol to below 100 mg/dL in patients with diabetes and coronary artery disease. The survey covered a 5-year period, from July 1998 to June 2003, and included 15 randomly chosen residents who were in training for 3 consecutive years. Charts were randomly selected from residents' clinics using International Classification of Diseases-9 codes for coronary artery disease or diabetes mellitus with hyperlipidemia. Five hundred fifty charts were reviewed. Only 41 (7.45%) met the inclusion criteria. Results: Analysis of data using Epi-Info 2002 (Centers for Disease Control and Prevention, Atlanta, GA) revealed that only 68.3% of patients with diabetes and coronary artery disease reached target LDL cholesterol levels. Of the patients who reached target levels, only 42.9% maintained them. Analysis of variance and chi-square tests revealed that the frequency of cholesterol measurement, but not the frequency of physicians' visits, was associated with a higher likelihood of reaching the target LDL level. Conclusion: There was a suboptimal compliance among internal medicine residents in the frequency of screening for, reaching, and maintaining the target LDL cholesterol level, according to the latest NCEP-ATP guidelines, among high-risk patients with hyperlipidemias.

Bakgrund: Deposition av fibrillär amyloid beta 1-42 (Aβ) i hjärnan är ett välkänt kännetecken för den neurodegenerativa sjukdomen Alzheimer’s (AD). Dessa ansamlingar påverkar pericyter, en celltyp involverad i blodkärlsfunktion och upprätthållande av blodhjärnbarriären (BBB). Pericyter uttrycker både receptorn low density lipoprotein receptor related protein 1 (LRP-1) till vilken Aβ1-42 binder, och proteoglykanet NG2. NG2 har stor betydelse för pericyters samspel med endotelceller och i sin lösliga form (sNG2) främjar den angiogenes. Tidigare studier har visat att mängden NG2 som klyvs från pericyter förändras när de stimuleras med Aβ1-42. Syfte: Att undersöka om Aβ1-42 påverkar NG2 klyvning via LRP-1 Metod: Human brain vascular pericytes (HBVP) stimulerades med monomera, oligomera och fibrillära Aβ1-42 preparationer. Uttrycket av LRP-1 tystades med small interfering (si) LRP-1 och knockdown efficiency analyserades med Western Blot (WB). Även Aβ1-42 preparationer undersöktes med WB. Cellviabilitet mättes med laktatdehydrogenas (LDH) test och proteininnehåll med Bradford analys. Slutligen mättes mängden sNG2 i pericytmedium med hjälp av enzyme-linked immunosorbant assay (ELISA) baserad på electrochemiluminescence (Mesoscale). Resultat: Preparationerna med monomer och oligomer Aβ1-42 ökade NG2 klyvning. Denna Aβ1-42 inducerade ökning försvann när cellernas LRP-1 tystats. Aβ1-42 fibrillpreparationerna inhiberade däremot NG2 klyvningen oavsett närvaro av LRP-1. Aβ1-42 monomerpreparationer inducerade celldöd hos HBVP med LRP-1 men inte hos de HBVP där LRP-1 tystats, och cellviabiliteten hos HBVP ökade hos celler som stimulerats med Aβ1-42 fibrillpreparation och där LRP-1 tystats. Konklusion: Resultaten visar att Aβ1-42 monomer och oligomer påverkar NG2 klyvning via LRP-1. Däremot verkar Aβ1-42 fibrill istället påverka NG2 klyvning via en annan signalväg. Studien belyser hur Aβ1-42 kan påverka pericyter, vilket kan föreligga vaskulära förändringar kopplade till AD patologi. / Background: The deposition of fibrillar amyloid beta 1-42 (Aβ) in the brain is a well-known characteristic for the neurodegenerative Alzheimer’s disease (AD). These accumulations affect pericytes, a cell type implicated in vessel function and maintenance of the blood-brain barrier (BBB). Pericytes express both the receptor low-density lipoprotein receptor related protein 1 (LRP-1), to which Aβ1-42 binds, and the proteoglycan NG2. NG2 is important for the interaction between pericytes and endothelial cells and in its soluble form (sNG2) it promotes angiogenesis. Earlier studies have shown that the amount of NG2 shed from pericytes is altered when stimulated with Aβ1-42. Purpose: To investigate whether the Aβ1-42 influence on NG2 shedding is mediated via LRP-1. Method: Human brain vascular pericytes (HBVP) were stimulated with monomeric, oligomeric and fibrillar preparations of Aβ1-42. Expression of LRP-1 was knocked down by small interfering (si) LRP-1 silencing and knockdown efficiency was analysed with Western blot (WB). Aβ1-42 preparations were also analysed with WB. Cell viability was measured with lactate dehydrogenase (LDH) test and protein concentrations were determined with Bradford assay. Finally the amount of sNG2 in pericytemedium was measured with enzyme-linked immunosorbant assay (ELISA) baserad på electrochemiluminescence (Mesoscale) Results: Monomer and oligomer Aβ1-42 increased NG2 shedding, this Aβ1-42 induced increase was not found in HBVP with a silenced LRP-1. In contrast, fibrillar Aβ1-42 inhibited NG2 shedding regardless of LRP-1 presence. Monomer Aβ1-42 preparations induced cell death of HBVP with LRP-1 but not of HBVP without LRP-1, and cell viability of HBVP lacking LRP-1 was increased after fibrillar Aβ1-42 exposure. Conclusion: The results indicate a monomeric and oligomeric Aβ1-42 induced impact on NG2 shedding via LRP-1. However it appears as if fibrillar Aβ1-42 doesn’t affect NG2 shedding via LRP-1 but rather inhibits the process via another unknown receptor. The study highlights how Aβ1-42 can affect pericytes, which may underlie the vascular changes linked to AD pathology.

Background: Several previous studies have reported that dyslipidemia is associated with the risk of hypertension, but these studies are mainly conducted in European and US populations, with a very few studies in the Asian population. Moreover, the effects of atherosclerotic indices, including atherogenic coefficient (AC) and atherogenic risk of plasma (AIP), on hypertension in Asians have not been well described so far. Methods: From 2010 to 2016, altogether 211,833 Chinese adults were ultimately recruited at the health centers in 11 Chinese cities (including Shanghai, Beijing, Nanjing, Suzhou, Shenzhen, Changzhou, Chengdu, Guangzhou, Hefei, Wuhan, and Nantong). Differences in continuous variables between the two groups were analyzed by the Mann–Whitney test, while those in categorical variables were examined by the Chi-squared test. Logistic regression was applied to evaluate the association between lipid profiles and the risk of hypertension. The predictive values of AC and AIP for the incidence of hypertension were analyzed using the area under the receiver operating characteristic (ROC) curve. Meanwhile, Bayesian network (BN) models were performed to further analyze the associations between the different covariates and the incidence of hypertension. Results: A total of 117,056 participants were included in the final analysis. There were significant differences in baseline characteristics between normotension and hypertension groups (p < 0.001). In multivariate logistic regression, the risk of hypertension increased by 0.2% (1.002 [1.001–1.003]), 0.2% (1.002 [1.001–1.003]), and 0.2% (1.002 [1.001–1.003]) per 1 mg/dl increase in total cholesterol (TC), low-density lipoprotein (LDL), and non-high-density lipoprotein cholesterol (non-HDL-c), respectively. However, after adjusting for body mass index (BMI), an increase in HDL level was associated with a higher risk of hypertension (p for a trend < 0.001), and the risk of hypertension increased by 0.6% per 1 mg/dl increase in HDL-c (1.006 [1.003–1.008]). In women, AC had the highest predictive value for the incidence of hypertension with an area under the curve (AUC) of 0.667 [95% confidence interval (CI): 0.659–0.674]. BN models suggested that TC and LDL were more closely related to the incidence of hypertension. Conclusions: Overall, lipid profiles were significantly abnormal in the hypertensive population than in the normotensive population. TC and LDL were strongly associated with the incidence of hypertension. TC, LDL, and non-HDL-c levels show a positive association, HDL-c shows a negative association, while TG is not significantly associated with the risk of hypertension. After adjusting for BMI, HDL-c turns out to be positively associated with the risk of hypertension. In addition, AC has a good predictive value for the incidence of hypertension in women.