published_or_final_version / Pharmacology / Doctoral / Doctor of Philosophy

The objective of this research was to examine the effects of sitosterol and sitostanol supplementation on plasma cholesterol levels and cholesterol metabolism in hypercholesterolemic subjects consuming a fixed foods diet in a four-phase crossover design. It was hypothesized that addition of either phytosterols, phytostenols, or a 50:50 mixture of sterols and stanols to butter would reduce circulating cholesterol levels, despite butter's hypercholesterolemic effect, through actions involving cholesterol absorption, synthesis, and turnover rates. The data obtained indicate that in their free, unesterified form, plant sterols and stanols lower plasma LDL cholesterol equivalently in hypercholesterolemic subjects. Results of this study provide new data that phytosterols and stanols function by suppressing cholesterol absorption while increasing cholesterol synthesis, however, the de-suppression in synthesis cannot fully compensate for the decrease in absorption making the treatment effective, thus may assist in the development of a food which offers health-promoting advantages related to the prevention of cardiovascular disease.

Background. A high ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol, in addition to increased levels of small low-density lipoprotein (LDL) particles, are important indicators of cardiovascular disease risk. Therefore, interventions that combine the lowering of total cholesterol and raising of HDL cholesterol concentrations that also increase LDL particle size, may be preventive against cardiovascular disease. Plant sterols decrease total cholesterol and LDL cholesterol levels by 10-15%, while exercise increases HDL cholesterol levels by 4-22%. In view of their complementary effects, combining plant sterols with exercise would appear to be an effective lifestyle therapy to decrease the risk of future cardiovascular disease. / Objective. The aim of this study was to examine the independent and combined effects of plant sterols and exercise on blood lipid levels, and LDL particle size in previously sedentary, hypercholesterolemic adults. An additional objective of this trial was to assess the underlying mechanism by which this combination therapy modulates whole body cholesterol metabolism, to in turn improve lipid profiles. / Methods. In an 8-week, parallel-arm trial, 84 subjects were randomized to 1 of 4 interventions: (1) plant sterols and exercise,(2) plant sterols alone, (3) exercise alone, or (4) control. Blood lipid concentrations were measured using enzymatic kits, and LDL particle size was assessed using polyacrylamide gel electrophoresis. Cholesterol absorption and synthesis were determined using the single isotope single tracer technique and the deuterium incorporation approach, respectively. / Results. Plant sterol supplementation decreased (P < 0.01) total cholesterol concentrations by 8.2% when compared to baseline. Exercise increased (P < 0.01) HDL cholesterol levels by 7.5% while decreasing (P < 0.01) triglyceride concentrations by 13.3% when compared to baseline. Exercise reduced (P < 0.05) post-treatment LDL peak particle size from 255 to 253 A, and decreased (P < 0.05) the proportion of large LDL particles by 13.1%. Plant sterols had no effect on particle size distribution. Plant sterol supplementation decreased (P < 0.01) intestinal cholesterol absorption by 18%, while exercise had no effect on cholesterol absorption. Non-significant increases in cholesterol synthesis rates of 63%, 59%, and 57%, were observed in the combination, exercise, and plant sterol groups, respectively, relative to control. / Conclusion. These findings suggest that this combination therapy yields the most favourable alterations in lipid profiles when compared to each intervention alone. This combined intervention exerts its beneficial effects on lipid profiles by suppressing intestinal cholesterol absorption. Therefore, this lifestyle therapy may be an effective means of decreasing the risk of cardiovascular disease in hypercholesterolemic adults.

To evaluate the relative efficacy of plant sterols (PS) esterified with the fatty acids from fish oil (PS-FO), olive oil (PS-OO) and sunflower oil (PS-SO) on blood lipid and PS concentrations, 21 hyperlipidemic subjects were randomly assigned to each of five treatments for 28 days using a cross-over design. The results showed that: (1) in a comparison of olive oil (OO), fish oil (FO), PS-FO and PS-SO subgroup, PS-FO reduced triacylglycerols (TG) relative to PS-SO. Total cholesterol (T-C)/high-density lipoprotein cholesterol (HDL-C) ratio was reduced with PS-FO compared with FO. Plasma PS levels were increased with PS-SO and PS-FO. (2) in a comparison of OO, PS-SO and PS-OO subgroup, PS-OO had a larger decrease in T-C than OO, while PS-SO and OO reduced T-C equally. Both PS-SO and PS-OO elevated plasma PS levels. Overall, PS-FO and PS-OO have a higher potential for decreasing the risk of cardiovascular disease in hyperlipidemic subjects than PS-SO and OO supplementations.

Plant sterols are effective cholesterol-lowering agents; however, recent evidence suggests that this treatment may not be safe and beneficial in all individuals. This study determined whether high and low baseline circulating plasma campesterol and sitosterol are related to subsequent changes in plasma LDL-C, plant sterol or CRP levels, after accounting for plant sterol supplementation in hypercholesterolemic men (n=82). This trial was a 2-phase randomized cross-over design consisting of a controlled diet with and without a dose of 2.0 g/d of plant sterols over 4 weeks. There was no significant difference in plasma LDL-C, in the elevation of plasma plant sterol or in the changes of CRP levels for high and low groups, respectively. In view of these data, a supplement of 2.0 g/d of plant sterols should be viewed as a safe and beneficial cholesterol-lowering therapy for all individuals, with respect to their baseline plasma plant sterol levels.

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1969. / Bibliography: leaves [131]-135. / ix, 135 l graphs, tables

Orientador: Eros Antonio de Almeida / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-10T01:47:47Z (GMT). No. of bitstreams: 1 Hernandes_DorivalBlaquer_M.pdf: 1038635 bytes, checksum: f87a9f0cf9cca81b3827e6b7fefdbb9b (MD5) Previous issue date: 2007 / Resumo: Objetivo: este estudo teve como objetivo detectar o efeito da rosuvastatina sobre os lípides plasmáticos, peroxidação lipídica, colesterol tecidual e disfunção endotelial e comparar seus efeitos com a atorvastatina em coelhos hipercolesterolêmicos. Métodos: Quarenta coelhos machos da raça Nova Zelândia foram distribuídos aleatoriamente em quatro grupos: Grupo Hipercolesterolêmico (GH), Grupo não Hipercolesterolêmico (GN), Grupo Atorvastatina (GA) e Grupo Rosuvastatina (GR) (N = 10). Todos os animais foram alimentados com dieta complementada com gordura de côco 10% e colesterol 0,5% por 45 dias e água a vontade. Após 15 dias amostras de sangue foram colhidas dos grupos através de punção venosa para determinação do colesterol plasmático total. A rosuvastatina era administrada por gavagem, na dose de 2,5 mg/dia/animal e a atorvastatina na dose de 10 mg/dia/animal aos Grupos GR e GA. No final do experimento, novas amostras de sangue foram coIbidas para determinação do colesterol total e isolamento de LDL. Os animais foram sacrificados por deslocamento cervical, êra realizada Toracotomia, a aorta era removido e preparado anéis de 5mm para o estudo da função endotelial, medindo colesterol tecidual, MDA na parede da aorta e LDLs. Os resultados foram comparados por métodos estatísticos não - paramétricos. Resultados: Ao analisar os resultados deste trabalho, podem ser observadas redução dos níveis de CT, 44,1 % e 66%, TG 53,16%, 23,11 %, LDL 53% e de, 40,68%, e um aumento de 17,23%, 36,98% do HDL e uma melhora na função endotelial de 33,09%, 22,37%, respectivamente, em relação a comparação GA e GR. Com o GH. Conclusão: Os resultados mostraram que rosuvastatina e atorvastatina foram equivalentes na redução das susceptibilidades de LDL de sofrer peroxidação, diminuindo o colesterol tecidual e melhorando a função endotelial / Abstract: Objective: The aim of this study was to detect the effect of the rosuvastatin on plasmatic lipids, lipidic peroxidation, tis sueI cholesterol, and endothelium disfunction and to compare its effect with the atorvastatin in hypercholesterolemic rabbits. Methods: Forty male New Zealand white rabbits were randomized in Four Groups: Group Hypercholesterolemic (GH), Group No Hypercholesterolemic (GN), Group Atorvastatin (GA) and Group Rosuvastatin (GR). (N=lO). AlI the animaIs were fed with diet supplemented with fat of coconut 10% and cholesterol 0.5% w/w per 45 days. After 15 days samples of blood were removed from the groups through venous punction for total plasmatic cholesterol determination. Then the rosuvastatin was managed by gavage, in the dose of 2,5mg and Atorvastatin in the dose of 10mg per day to each animal of Groups GR. and GA. In the end of the experiment, new samples of blood were renioved for determination of the cholesterol and isolation pf LDL. The animals were sacrificed by displacement of the cervical column. Medium Toracotomia was carried out and the aorta was removed for ring preparation for study of the endothelium function, measured of tissue cholesterol, MDA in the walI of aorta and LDLs. The results were compared by not-parametric statistical methods. Results: When analyzing the results of this work, a reduction in the CT levels can be observed, of 44,1 % and 66%, TG 53.16%, 23.11%, LDL 53% and of, 40.68%, and an increase of 17,23%, 36.98% of HDL, 33.09%, 22.37% in the endothelium function respectively for the compared GA and GR. with the GH. Conclusion: The results have sh6wn that rosuvastatin and atorvastatin were equivalent in reducing the susceptibilities of LDL to suffer peroxidation, in decreasing the tecidual cholesterol and improving the endothelium function / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

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