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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
781

Molecular magnetic resonance imaging of vascular inflammation using microparticles of iron oxide

Akhtar, Asim January 2010 (has links)
One approach that has demonstrated success in the field of molecular imaging utilizes microparticles of iron oxide (MPIO) conjugated to specific antibodies and/or peptides to provide contrast effects on MRI in relation to the molecular expression of a specified target. The experimental aims of this thesis were 1) to investigate the ability of VCAM-1 and P-selectin targeted MPIO to detect the expression of VCAM-1 and P-selectin on the activated endothelium in-vitro and in-vivo in mouse models of renal and cerebral ischemia reperfusion injury, and 2) develop a novel contrast agent for imaging αvβ3-integrin expression in angiogenesis using RGD peptide conjugated MPIO (RGD-MPIO) in-vitro. MPIO (1.0 µm) were conjugated to monoclonal antibodies against VCAM-1 (VCAM-MPIO) or P-selectin (PSEL-MPIO). In vitro, MPIO bound in a dose-dependent manner to tumor necrosis factor (TNF)-alpha stimulated sEND-1 endothelial cells when conjugated to VCAM-1 (R² = 0.88, P<0.01) and P-selectin antibodies (R² = 0.93, P<0.01), reflecting molecular VCAM-1 and P-selectin mRNA and protein expression. Mice subjected to unilateral, transient (30 minutes) renal ischemia and subsequent reperfusion received intravenous VCAM-MPIO and PSEL-MPIO (4.5 mg iron/kg body weight). In ischemic kidneys, MR related contrast effects of VCAM-MPIO were 4-fold higher than unclamped kidneys (P<0.01) and 1.5-fold higher than clamped kidneys of PSEL-MPIO injected mice (P<0.05). VCAM-MPIO binding was less evident in IRI kidneys pre-treated with VCAM-1 antibody (P<0.001). VCAM-1 mRNA expression and VCAM-MPIO contrast volume were highly correlated (R² = 0.901, P<0.01), indicating that quantification of contrast volume reflected renal VCAM-1 transcription. In mice subjected to cerebral ischemia, contrast volume was 11-fold greater in animals injected with VCAM-MPIO versus control IgG-MPIO (P<0.05). Finally, S-nitroso-N-acetylpenicillamine (SNAP) stimulated HUVEC-C cells, which express αvβ3-integrin, showed 44-fold greater RGD-MPIO binding than unstimulated cells (P<0.001) and 4-fold greater RGD-MPIO binding than SNAP stimulated cells blocked with soluble RGD peptide (P<0.001) in-vitro. This thesis demonstrated that targeted MPIO exhibited contrast effects that defined and quantified the molecular expression of specific targets through the use of high-resolution MRI in in-vitro and in-vivo models of vascular inflammation.
782

Role of the haematopoietic transcription factor SCL in mesoderm development

Green, Angela Lisa January 2012 (has links)
During embryonic development, precursor cells commit to specific cell fates in response to environmental cues through the establishment of lineage-specific gene expression programmes. Transcription factors are important downstream effectors of signalling pathways that initiate and maintain cell fate decisions. The haematopoietic transcription factor SCL (TAL-1) is an essential regulator of embryonic blood development. However, the exact stage at which SCL is required, its mechanisms of action, and its genomic targets are poorly understood. Characterising, jiow SCL functions - , during haematopoietic development will provide insights into how stern cells are specified. Using the embryonic stem cell/embryoid body (ES/EB) system to model early mouse development, we describe a critical role for SCL in mesoderm patterning. SCL is first expressed in PDGFRa+ FLK1+ mesoderm populations which contain lateral, paraxial and cardiac precursors. Through loss- and gain-of-function studies, we show that SCL drives lateral mesoderm specification and activates the haematopoietic programme in a direct DNA-binding independent manner, while actively repressing alternative mesodermal fates, specifically cardiac development, in a DNA-binding dependent manner. At a molecular level, we have identified direct genomic targets of SCL in Flk-1 + mesoderm populations. These include haematopoietic and cardiac transcription factors, cardiac-specific structural proteins, signalling proteins and general transcriptional repressors; thereby strengthening the dual function of SCL in mesoderm patterning. Finally, we have shown that the cardiac transcription factor GATA4 acts in a reciprocal manner, specifying cardiac precursors while repressing a lateral mesoderm fate. Collectively, this implicates SCL as a critical transcriptional regulator of cell fate decisions in early mesodermal precursors, employing distinct molecular mechanisms to impose a blood programme. Moreover, and extending earlier reports, we document the existence of an antagonistic cross-talk between haematopoietic and cardiac lineages during mesoderm patterning. In conclusion, this work offers a cellular and molecular platform to begin to dissect the network of genetic interactions involved in these developmental processes.
783

Étude d’un modèle murin de vieillissement sur la sténose valvulaire aortique

Trapeaux, Juliette 12 1900 (has links)
La sténose valvulaire aortique (SVA) est une pathologie associée au vieillissement et aux facteurs de risque cardiovasculaire. Afin d’étudier la SVA et d’explorer de nouvelles thérapies, plusieurs modèles animaux ont été récemment développés, mais la plupart de ces modèles ciblent les mécanismes de développement de la SVA reliés à l’hypercholestérolémie. Le syndrome de Werner (WS) est une maladie caractérisée par un vieillissement prématuré. Récemment, il a été découvert que des souris mutantes ayant une délétion du domaine hélicase du gène Werner, responsable du WS, démontraient un profile hémodynamique typique de la SVA. De ce fait, nous avons émis l’hypothèse que ces souris pourraient développer une SVA plus rapidement que des souris de type sauvage. Nous avons donc étudié les effets cette mutation chez des souris WrnΔhel/Δhel, en comparant le taux de progression d’une SVA entre des souris WrnΔhel/Δhel (WrnΔhel) et des souris de type sauvage comme groupe contrôle. À la suite d’une diète riche en sucre et en gras sur une période de 24 semaines, les souris WrnΔhel ont démontré une diminution plus prononcée de leur aire de valve aortique (mesures échocardiographiques) que les souris contrôles, supportée par les analyses histologiques concernant la fibrose des valves aortiques. Les souris n’ont toutefois développé aucun signe évident d’athérosclérose comme l’infiltration de lipides ou l’inflammation, bien que certaines caractéristiques liées à la dysfonction endothéliale semblent être augmentées chez les souris WrnΔhel. D’autres mesures échocardiographiques indiquant une SVA, comme une hypertrophie du ventricule gauche dans le groupe WrnΔhel, ont été obtenues. Nous avons aussi observé des indices de vieillissement plus marqués quant aux analyses sanguines et de la moelle osseuse des souris WrnΔhel en comparaison avec les souris contrôles. Par conséquent, ce modèle expérimental de vieillissement pourrait être utilisé pour les études futures sur la SVA sans les principaux effets athérogéniques des autres modèles expérimentaux. / Aortic valve stenosis (AVS) is associated with aging and classical cardiovascular risk factors. Different animal models were recently developed to study AVS and explore new therapies, however, most of these models rely almost exclusively on hypercholesterolemia-related mechanisms for AVS development. Werner syndrome (WS) is a disorder characterized by premature aging. It was recently demonstrated that mutant mice with a deletion of the helicase domain of the Werner gene, the gene responsible for WS, showed hemodynamic profile typical of AVS. We therefore hypothesized that mice with the WrnΔhel deletion could develop AVS earlier than wild-type (WT) mice. We studied the effect of the WrnΔhel mutation by comparing the rate of progression of AVS in homozygous mutant versus WT mice. By twenty-four weeks on a high-fat/high-carbohydrate diet, WrnΔhel/Δhel (WrnΔhel) mice showed a stronger decrease of the aortic valve area measured by serial echocardiography than WT mice, supported by histological analyses of valve fibrosis but without developing major signs of atherosclerosis such as lipid infiltration or increased inflammation. Some features linked to endothelial dysfunction also appeared to be increased in WrnΔhel mice. Other echocardiographic measurements were typical of AVS, such as left ventricle hypertrophy in the WrnΔhel group. We also observed stronger aging properties from WrnΔhel mice bone marrow and blood analyses compared to the WT group. Consequently, this experimental aging model could be used for AVS research without the major confounding atherogenic effects of other experimental models.
784

La PCSK9 humaine, une molécule aux multiples facettes métaboliques et une cible thérapeutique prometteuse : études de régulation in vitro et in vivo

Dubuc, Geneviève 09 1900 (has links)
La proprotéine convertase subtilisine/kexine-9 (PCSK9) a été identifiée comme le troisième locus impliqué dans l’hypercholestérolémie autosome dominante (ADH). Les deux autres gènes impliqués dans l’ADH encodent le récepteur des lipoprotéines de faible densité (LDLR) et l’apolipoprotéine B. La PCSK9 est une convertase qui favorise la dégradation du LDLR dans les hépatocytes et augmente le niveau plasmatique de cholestérol des LDL (LDL-C). Les mutations « gain de fonction » de la PCSK9 sont associées à un phénotype d’hypercholestérolémie familiale, tandis que les variantes « perte de fonction » sont associées à un LDL-C réduit et à un risque coronarien plus faible. Pour élucider le rôle physiologique de la PCSK9, nous avons étudié sa régulation génique. En utilisant le RT-PCR quantitatif dans des hépatocytes humains, nous avons analysé la régulation de PCSK9 sous différentes conditions modulant l’expression des gènes impliqués dans le métabolisme du cholestérol. Nous avons démontré que l’expression de la PCSK9 était induite par les statines de manière dose-dépendante et que cette induction était abolie par le mévalonate. De plus, le promoteur de PCSK9 contenait deux motifs conservés pour la régulation par le cholestérol : le sterol regulatory element (SRE) et un site Sp1. La PCSK9 circule dans le plasma sous des formes mature et clivée par la furine. Grâce à notre anticorps polyclonal, nous avons mis au point un test ELISA mesurant la PCSK9 plasmatique totale. Une étude transversale a évalué les concentrations plasmatiques de PCSK9 chez des sujets sains et hypercholestérolémiques, traités ou non par des statines ou une combinaison statine/ezetimibe. Chez 254 sujets sains, la valeur moyenne de PCSK9 (écart-type) était de 89,5 (31,9) µg/L. La concentration plasmatique de la PCSK9 corrélait avec celle de cholestérol total, du LDL-C, des triglycérides (TG), de la glycémie à jeun, l’âge et l’indice de masse corporelle. Le séquençage de PCSK9 chez des sujets aux extrêmes de la distribution des concentrations de PCSK9 de notre cohorte a révélé la présence d’une nouvelle variation « perte de fonction » : R434W. Chez 200 patients hypercholestérolémiques, la concentration de PCSK9 était plus élevée que chez les sujets sains (P<0,04). Elle a augmenté avec une dose croissante de statine (P<0,001), et a augmenté encore plus suite à l’ajout d’ezetimibe (P<0,001). Chez les patients traités, ceux présentant une hypercholestérolémie familiale (HF; due à une mutation du LDLR) avaient des concentrations plus élevées de PCSK9 que les non-HF (P<0,005), et la réduction de LDL-C corrélait positivement avec la concentration de PCSK9 atteinte de la même manière dans les deux sous-catégories (P<0,02 et P<0,005, respectivement). Par ailleurs, une incubation des cellules HepG2 (hépatocytes) et Caco-2 (entérocytes) avec de l’ezetimibe a provoqué une augmentation de l’ARNm de PCSK9 et de NPC1L1 de 1,5 à 2 fois (P<0,05), mais aucune variation significative de PCSK9 sécrétée n’a été observée, suggérant que ces lignées cellulaires ne sont pas un modèle idéal. Nous avons également mesuré le niveau de PCSK9 chez 1 739 Canadiens-français âgés de 9, 13 et 16 ans. La valeur moyenne (écart-type) de PCSK9 dans cette cohorte était de 84,7 (24,7) µg/L, légèrement plus basse que dans la cohorte d’adultes (89,5 (31,9) µg/L). Chez les garçons, la PCSK9 circulante diminuait avec l’âge, tandis que c’était l’inverse chez les filles. Il y avait des associations positives et significatives entre la PCSK9 et la glycémie à jeun, l’insulinémie, le HOMA-IR, et les paramètres lipidiques (TC, LDL-C, TG, HDL-C, apoAI et apoB). Dans l’analyse multivariée, une hausse de 10% de l’insulinémie à jeun était associée à une augmentation de 1 à 2% de PCSK9. La régulation de PCSK9 est typique de celle d’un gène impliqué dans le métabolisme des lipoprotéines et est probablement la cible du facteur de transcription «sterol regulatory element-binding protein » (SREBP-2). La concentration plasmatique de la PCSK9 est associée avec l’âge, le sexe, et de multiples marqueurs métaboliques chez les enfants et les adultes. La détection de la PCSK9 circulante chez les sujets HF et non-HF signifie que ce test ELISA spécifique à PCSK9 pourrait servir à suivre la réponse à la thérapie chez un grand éventail de sujets. PCSK9 semble être une cible thérapeutique prometteuse dans le traitement de l’hypercholestérolémie et de la maladie cardiovasculaire. / Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been identified as the third locus implicated in autosomal dominant hypercholesterolemia (ADH). The two other known genes implicated in ADH encode the low-density lipoprotein receptor (LDLR) and apolipoprotein B. PCSK9 is a protein convertase that post-translationally promotes the degradation of the LDLR in hepatocytes and increases plasma LDL cholesterol concentration (LDL-C). Heterozygote “gain-of-function” mutations of PCSK9 are associated with the familial hypercholesterolemia phenotype, whereas “loss-of-function” variants are associated with reduced LDL-C concentrations and lower coronary risk. As an approach toward the elucidation of the physiological role(s) of PCSK9, we studied its transcriptional regulation. Using quantitative RT-PCR, we assessed PCSK9 regulation under conditions known to regulate genes involved in cholesterol metabolism in HepG2 cells and in human primary hepatocytes. We found that PCSK9 expression was strongly induced by statins in a dose-dependent manner and that this induction was efficiently reversed by mevalonate. The PCSK9 promoter contains two typical conserved motifs for cholesterol regulation: a sterol regulatory element (SRE) and an Sp1 site. PCSK9 circulates in plasma as mature and furin-cleaved forms. A polyclonal antibody against human PCSK9 was used to develop an ELISA that measures total plasma PCSK9 rather than only the mature form. A cross-sectional study evaluated plasma levels in normal and hypercholesterolemic subjects treated or untreated with statins or statin plus ezetimibe. In 254 healthy subjects, the mean plasma PCSK9 (SD) concentration was 89 (32) µg/L. PCSK9 levels correlated positively with plasma cholesterol, LDL-C, triglycerides, fasting glucose, age and body mass index. Sequencing PCSK9 from subjects at the extremes of PCSK9 plasma distribution revealed a new loss-of-function R434W variant. In 200 hypercholesterolemic patients, circulating PCSK9 was higher than in controls (P<0.04), increased with increasing statin dose (P<0.001), and further increased when ezetimibe was added (P<0.001). In treated patients (n = 139), those with familial hypercholesterolemia (FH; due to LDLR gene mutations) had higher PCSK9 values than non-FH (P<0,005), and LDL-C reduction correlated positively with achieved plasma PCSK9 levels to a similar extent in both subsets (P<0.02 and P<0.005, respectively). However, incubation with ezetimibe of HepG2 (hepatocytes) and Caco-2 (enterocytes) cells caused an increase in PCSK9 and NPC1L1 mRNA of 1.5 to 2-fold (P<0.05), but no significant rise in PCSK9 protein secretion, suggesting that these transformed cells are not an ideal model. We also studied PCSK9 levels in 1,739 French Canadian youth ages 9, 13, and 16 years old. The mean (SD) plasma PCSK9 concentration, measured by ELISA, was 84.7 (24.7) µg/L in the cohort, slightly lower than in the adult cohort (89.5 (31.9) µg/L. In boys, plasma PCSK9 decreased with age, whereas the inverse was true for girls. There were significant positive associations between PCSK9 and fasting glucose, insulin, and HOMA-IR (homeostasis model assessment of insulin resistance). In multivariable analysis, a 10% higher fasting insulin was associated with a 1%-2% higher PCSK9 in both sexes. There were also positive associations between PCSK9 and total cholesterol, LDL-C, and triglycerides, as well as with HDL-C and apolipoproteins A1 and B. PCSK9 regulation is typical of that of the genes implicated in lipoprotein metabolism. In vivo, PCSK9 is probably a target of the transcription factor “sterol response element-binding protein” (SREBP)-2. The PCSK9 plasmatic concentration is associated with age, sex, and multiple metabolic markers in youth and adult samples. The detection of circulating PCSK9 in both FH and non-FH subjects means that this PCSK9 ELISA test could be used to monitor response to therapy in a wide range of patients. PCSK9 seems to be a promising drug target in the treatment of hypercholesterolemia and coronary heart disease.
785

EFFECT OF RENIN ANGIOTENSIN SYSTEM INHIBITION ON CARDIOVASCULAR SEQUELAE IN ELDERLY HYPERTENSIVE PATIENTS WITH INSULIN RESISTANCE

Zreikat, Hala 16 September 2009 (has links)
Background: Insulin resistance may play a pathogenic role in cardiovascular disease (CVD). Resistance to insulin has been associated with obesity, hypertension, and abnormal glucose and lipid metabolism. The constellation of these features among insulin resistant subjects has been called the metabolic syndrome. Prevalence of the metabolic syndrome increases with age and is most common in the elderly. Different criteria have been proposed to define the metabolic syndrome (ATP, WHO, AACE, EGIR). Current management of metabolic syndrome focuses on the specific risk factors that the patient may have without targeting the underlying insulin resistance. Angiotensin Converting Enzyme Inhibitors (ACEI) and Angiotensin Receptor Blockers (ARB) are widely used antihypertensive medications that may improve insulin sensitivity. We hypothesize that they can be used to reduce the long term cardiovascular complications in elderly hypertensive subjects with evidence of insulin resistance. In this study, we determined the effect of ACEI/ARB on the long term development of CVD in hypertensive non-diabetic elderly patients with the metabolic syndrome, as well as in patients with insulin resistance. Methods: Our research project utilizes the Cardiovascular Health Study (CHS) dataset. This dataset is a community based observational study where elderly participants were randomly selected and followed up for 11 years and the time to any cardiovascular event was recorded. In our project, we included hypertensive, non-diabetic individuals, with evidence of metabolic syndrome or insulin resistance, but had not experienced cardiovascular events at baseline. Cox regression model was used to evaluate the effect of ACEI/ARB on the time to the first cardiovascular event compared to the other antihypertensive medications adjusting for possible confounders such as age, race, gender, smoking status, triglycerides, LDL levels, systolic blood pressure, development of diabetes, congestive heart failure (CHF) and the number of anti-hypertensives. Results: In elderly hypertensive non-diabetic subjects with the metabolic syndrome according to the ATP and the WHO criteria, the hazard ratio for CVD associated with the use of ACEI/ARB was 0.65 or 0.68 (with 95 % C.I. of [0.45, 0.98], and [0.48, 0.96]) respectively when compared to the group exposed to the other anti-hypertensives. When the metabolic syndrome was defined according to the AACE and EGIR, the use of ACE/ARB was associated with hazard ratios for CVD equal to 0.74 and 0.899, respectively (with 95 % C.I. of [0.54, 1.09] and [0.61, 1.34]) compared to the use of the other anti-hypertensives. Hypertensive non-diabetic elderly subjects who were insulin resistant as evidenced by a HOMA-IR in the upper quartile, had a hazard ratio for CVD of 0.78 (95 % C.I. [0.56, 1.09]) associated with the use of ACEI/ARB compared to the use of other anti-hypertensives. Conclusions: The effect of ACEI/ARB on the development of cardiovascular events differs according to the definition of the metabolic syndrome. Elderly hypertensive patients with the metabolic syndrome, defined by ATP and WHO, seem to have lower risk of CVD with ACEI/ARB compared to the other antihypertensive medications. However, this association is not significant in elderly hypertensive patients in the upper quartile of HOMA and in patients with the metabolic syndrome as defined by AACE and EGIR criteria.
786

EXPLORING THE ROLE OF INTERSECTIONALITY ON CARDIOVASCULAR DISEASE RISK IN SEXUAL MINORITIES

Harper, Leia 01 January 2016 (has links)
Background: Previous research has shown that sexual minority individuals (SM) are twice as likely to smoke, twice as likely to be overweight or obese, and less likely to be physically active than heterosexual persons; all of which place SMs at an increased risk for cardiovascular disease (CVD). While information on CVD risk by race/ethnicity and socioeconomic status is well documented, there is scant literature examining race, gender, and the potential CVD risk in SMs. The purpose of this study was to examine CVD risk in sexual minorities. Method: The current study used data from the National Longitudinal Study of Adolescent Health (Add Health). The Framingham multiple-risk assessment, which uses a calculation of age, smoking, BMI, and blood pressure, was used to predict vascular age and the risk of experiencing CVD event in the next 10 years. 54% of the sample was male, 62% white, and 4% identified as a SM. The sample was split into three groups: 1) 100% heterosexual (N=4363); 2) mostly heterosexual (N=509); and 3) SM (N=188). Results: There was a trend towards significance, p = .056, for mean differences in vascular age/actual age, for SM participants (M=10.07), compared to 100% heterosexual (M=9.1) and mostly heterosexual (M=8.66) participants. Mostly heterosexual participants were 1.62 times more likely, and SM participants were 1.97 times more likely to be current smokers when compared to 100% heterosexual participants. SM participants endorsed having significantly more drinks (M = 4.50) when compared to both 100% heterosexual (M = 3.80) and mostly heterosexual (M = 3.38) participants. SM participants were 1.7 times more likely to endorse having 5 or more drinks on one occasion. SM participants also reported significantly higher stress levels than the other two groups Conclusion: While the data for the current study did not provide sufficient evidence to suggest sexual orientation differences in Framingham risk scores, the findings remain noteworthy. SM showed increased risk in smoking and stress levels. Additionally, the Population-based longitudinal studies and surveillance data are essential and necessary in order to minimize disparities in risk factors and to reduce the likelihood of subsequent disease in SM population.
787

Epigenetic approaches to the study of macrophages in atherosclerosis

Reschen, Michael January 2015 (has links)
Coronary artery disease (CAD) is caused by atherosclerosis, a chronic inflammatory response to modified lipoproteins. A key pathophysiological event is the lipid-induced transformation of macrophages into lipid-laden foam cells and their accumulation in atherosclerotic plaques. Heritable CAD risk is associated with common genetic variants at over 40 genomic loci; the underlying causal mechanisms remain largely unknown and could affect transcriptional regulation in foam cells. Epigenetic and gene expression changes were measured in primary human macrophages before and after exposure to atherogenic, oxidized low-density lipoprotein—with resultant foam cell formation. This unbiased approach involved open chromatin mapping with formaldehyde-assisted isolation of regulatory elements with enhancer and transcription factor mapping using chromatin immuno-precipitation. Foam cell formation was associated with changes in a subset of open chromatin and enhancer sites that were strongly correlated with expression of nearby genes. OxLDL-regulated enhancers were enriched for several transcription factors—including C/EBP-beta— that have no previously documented role in foam cell formation. OxLDL exposure up-regulated C/EBP-beta expression and increased C/EBP-beta binding across the genome, most prominently around genes involved in inflammatory response pathways. Variants at CAD-associated loci were enriched in the subset of oxLDLregulated open chromatin sites. These included rs72664324 in an oxLDL-induced super-enhancer at the PPAP2B locus. OxLDL increased C/EBP-beta binding at rs72664324. C/EBP-beta binding, enhancer activity and oxLDL-induced upregulation of PPAP2B were stronger with the protective A allele of rs72664324. The PPAP2B protein product LPP3 was expressed in foam cells in human atherosclerotic plaques and was upregulated by oxLDL exposure in macrophages, so increasing the degradation of pro-inflammatory mediators. I also found several other CAD risk candidate genes were regulated by oxLDL: Phosphatase and actin regulator 1 (PHACTR1) and macrophage inducible Ca<sup>2+</sup> dependent C-type lectin (Mincle). This led us to find a novel expression-quantitative-trait locus for PHACTR1 in macrophages and define new glycolipid ligands for Mincle. Our results demonstrate a genetic mechanism contributing to CAD risk at the PPAP2B locus and highlight the value of integrating gene expression and epigenetic changes to study disease processes involving pathogenic environmental stimuli.
788

Avaliação econômica do uso de ômega-3 na redução dos fatores de risco cardiovascular: análise de custo-efetividade / Economic evaluation of omega-3 use in cardiovascular risk reduction factors: cost-effectiveness analysis

Giaimo, Cinthia Roman Monteiro di 15 May 2019 (has links)
INTRODUÇÃO: As doenças cardiovasculares (DCV) aparecem em primeiro lugar entre as principais causas de mortalidade no mundo, representando 46,2% do total de mortes, número muito próximo aos encontrados no Brasil, impactando os gastos com saúde. A prevenção baseia-se em estilo de vida saudável, contudo, uma vez instaladas, é consenso o tratamento medicamentoso com estatinas. Alguns tratamentos alternativos vêm sendo estudados como o ômega-3 (w-3) na prevenção das DCV. Apesar das evidências clínicas favoráveis, não existem muitos estudos acerca da viabilidade econômica de tais tratamentos. OBJETIVO: Avaliar o custo-efetividade das intervenções com w-3 isolado ou associado às estatinas na redução dos fatores de risco cardiovascular sob a perspectiva do Sistema Único de Saúde (SUS). MATERIAL E MÉTODOS: Para avaliar a efetividade do w-3 isolado e combinado com estatina foram utilizados os dados secundários do ensaio clínico CARDIONUTRI no momento basal e após 8 semanas. A amostra foi composta por 186 indivíduos com idade entre 30 e 74 anos divididos entre aqueles que não tomavam medicação e os que tomavam estatinas. Aleatoriamente, uma parcela deles recebeu cápsulas de 1 g de w-3 (37% de ácido eicosapentaenoico e 23% de docosaexaenoico) ou cápsulas de placebo. A recomendação era de que todos deveriam tomar 3 cápsulas ao dia, totalizando 3g/dia (de w-3 ou placebo) durante 8 semanas. Ao final, obteve-se quatro grupos: a) w-3; b) placebo; c) w-3 + estatina; e d) estatina. Para a avaliação do impacto foi usado o método Diferenças em Diferenças com a adição de variáveis de controle: densidade calórica do consumo alimentar, Índice de Massa Corporal (IMC), prática de atividade física, idade, sexo, raça, hábito tabagista, escolaridade e grau de adesão. Os custos dos tratamentos foram estimados com base no custo médio ponderado pelas probabilidades das eventuais intercorrências relacionadas a efeitos adversos e de sucesso e fracasso por meio do método da árvore de decisão. Foi considerado para fins do cômputo dos custos o período de 2 meses de tratamento. RESULTADOS: Nos quatro grupos, a maioria eram mulheres, obesas e com escore de risco muito alto para DCV. Os grupos w-3 e placebo possuíam maior escolaridade e renda comparadas a aqueles que tomavam estatinas. Todas as variáveis de controle foram estatisticamente significantes em pelo menos um dos modelos, exceto raça. A suplementação com w-3 associada às estatinas mostrou efetividade sobre HDLPEQUENA, com diminuição de 2,211 mg/dL e custo-efetividade de R$ 109,31 por redução em mg/dl da lipoproteína em 2 meses de tratamento. CONCLUSÃO: O tratamento com 1,8g de óleo de peixe isolado ou associado às estatinas em intervenção primária não evidenciou efeitos significativos nas mudanças dos parâmetros lipídicos, exceto no caso da HDLPEQUENA com o tratamento associado, mostrando não ser custo-efetivo na redução dos fatores de risco cardiovascular em geral. Em virtude da existência de controvérsias acerca de seus potenciais efeitos, sugere-se que os ensaios clínicos utilizem métodos estatísticos mais robustos para avaliar o impacto líquido da suplementação. / INTRODUCTION: Cardiovascular diseases (CVD) are among the leading causes of death worldwide, accounting for 46.2% of all cases, very close to those found in Brazil, impacting health expenses. Current prevention is based on a healthy lifestyle, and once a CVD diagnosis is made, the current consensus is drug treatments with statins. Some alternative treatments such as omega-3 (w-3) have been studied in the prevention of these diseases. However, despite favorable clinical evidence, there are not many studies of economic viability of this treatment. OBJECTIVE: To evaluate the cost-effectiveness of interventions with w-3 alone or associated with statins in reducing cardiovascular risk factors from the perspective of the Unified Health System (SUS). METHODS: To assess the effectiveness of w-3 alone and its combination with statin, the secondary data of the classic lipid profile and lipoprotein size of the CARDIONUTRI clinical trial were used at baseline and after 8 weeks. The sample consisted of 186 subjects aged 30 to 74 years randomly received capsules containing 3g of w-3 per day (37% of eicosapentaenoic acid and 23% of docosahexaenoic acid) or 3g of mineral oil (placebo). Capsules were randomly assigned to individuals who were not taking medication or were already taking statins, separated into four groups: a) w-3; b) placebo; c) w-3 associated with statins; d) statins. Data analysis was conducted using the Difference in Differences statistical method with the addition of control variables: caloric density of food consumption, Body Mass Index (BMI), physical activity practice, age, sex, race, smoking, educational level and adherence to the treatment. The treatment costs were estimated based on the weighted average cost by the probabilities of the eventual intercurrences related to adverse effects and of success and failure by means of the decision tree method elapsed in 2 months of treatment. RESULTS: In all four groups, the majority were women, obese and with a very high-risk score for CVD. W-3 and placebo groups had higher educational level and income compared to those who were already taking statins. All control variables were statistically significant in at least one of the models except race. W-3 supplementation showed efficacy on HDLSMALL among those who consumed w-3 + statins with a reduction of 2,211 mg /dL and cost-effectiveness R$ 109.31 per mg/dL for 2 months of treatment. CONCLUSION: The treatment with 1.8g of fish oil isolated or associated with statins in primary intervention did not show significant effects on changes in lipid parameters except HDLSMALL of interventions associated with statins. Therefore it was not cost-effective in reducing cardiovascular risk factors. Due to the existence of controversies about its potential effects, it is suggested that clinical trials use more robust statistical methods to assess the net impact of supplementation.
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Role genu pro FTO v genetické determinaci "civilizačních" onemocnění / Role of the FTO gene in the genetic determination of common multifactorial diseases

Dlouhá, Dana January 2014 (has links)
Obesity is a risk factor for development of cardiovascular disease, diabetes type 2 and some cancers. Newly detected genetic risk factor for body weight is the FTO gene ("fat mass and obesity associated"). The aim of this thesis was determine 1) whether the presence of risk alleles correlate with BMI in Czech population and to determine 2) whether there is an association between variants in the FTO gene and risk of myocardial infarction/ acute coronary syndrome (MI/ ACS), 3) renal failure (ESRD), or 4) incidence of colorectal cancer (CRC). We analyzed polymorphisms rs17817449 (first intron) and rs17818902 (3rd intron) using by PCR-RFLP and then also RT PCR. We found an association of the first intron variant (but not the 3rd one) and BMI in Czech control population. We have detected an association of 1st intron SNP and BMI changes during the intervention study in obese children, but not in obese females. We found a correlation between the risk allele and increased risk of ACS (OR 1.49) in patients with MI. In patients with ESRD was detected association between the risk allele and the risk of disease (OR 1.37). We didn't confirmed the association between rs17817449 and the development of CRC. Representative selected groups of the Czech populations "MONICA" and "HAPPIE" were used as controls. One...
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Correlação entre doença aterosclerótica, dieta hipercolesterolêmica e as perdas dentais, estudo em modelo animal / Relationship between atherosclerosis, hypercholesterolemic fat diet and tooth loss: Study in animal model

Santos, Endrigo Sperto Rodrigues dos 31 March 2009 (has links)
O objetivo deste trabalho foi de avaliar em Modelo animal, coelhos (raça Nova Zelândia) divididos em três grupos randomizados, (jovem com 60 dias (G1), um idoso com aterosclerose e ingestão de colesterol (G2) e um idoso com aterosclerose e sem ingestão do colesterol (G3)) se, a dieta rica em colesterol e a idade, causam lesões de aterosclerose e placas ateroscleróticas nos animais, alterações nos comprimentos dos dentes, aumento ou diminuição dos espaços periapicais dos dentes, perda óssea alveolar na maxila e mandíbula. Através da metodologia descrita e após as análises histológicas e morfológicas, verificou-se diferença estatisticamente significante, nas variáveis dos comprimentos dos dentes 1º prémolares superiores entre os grupos G3 versus G1 p<5%. médias de 1247,88 (p=0,017) e G3 versus G2, com diferença das médias de 1190,85 (p=0,025) ou seja o comprimento dos dentes fora diferente no grupo G2. Com relação à variável, espessura do osso alveolar, não ocorreu significância estatística, porém tendências de que este esteja sendo alterado. Com relação a variável espessura do espaço periapical fora verificado significância estatística com p=0,017 em relação ao G1, na região dos 1º Pré-molares, apresentando a diferença das médias (403,42) a favor do G2, ou seja aumento do espaço periapical. A variável da área de placa de aterosclerose, correlacionada, com os comprimentos dos dentes e espessura do osso alveolar, também teve resultado significante na região 1º e 2º pré-molares entre G2 e G3. com p=0,025 e r=0,476. Confirmando assim a correlação da aterosclerose, dietas hiperclesterolêmicas e as alterações da cavidade bucal e estrutura de sustentação dos dentes. / The aim of this study is, to evaluate on animal model (New Zealand rabbits), on different and randomized groups (G1 a young group, G2 an older rabbit, with atherosclerosis and ingesting hipercholesterolemic fat diet and another group G3, just an older group) investigated than the hipercholesterolemic fat diet induced atherosclerotic lesions and plaques in ascendant aorta, bone loss in maxillary and jaw, alterations on length of the tooth, alterations on tooth periapical spaces. By the methodology described and aplicated, before the histological and morphological analysis, was verified significant statistical variance in the length of the first premolar tooth and second premolar on maxillary region, the length of this tooth is reduced in G2 (p<5%). The medias are 1247,88 (p=0,017) and 1190,85 (p=0,025). Analyzing another variable on the alveolar bone thickness, was not found any statistical significance, but tendencies that this event may occur. According to another variable of the thickness found on the periapical space, it was verified a significant variable statistic such as p=0,017 related on G1, on first premolar region, suggesting a different statistic, between medias, favoring G2 meaning the increase of periapical space. The variable on the atherosclerosis plaque area, related to the teeth length and alveolar bone thickness, also showed significant results on first and second premolars regions between G2 and G3, with p=0,025 and r=0,476. That confirms the atherosclerosis correlations and hipercholestrolemic fat diet, also alterations in oral cavity and teeth implantation structure.

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