Philosophiae Doctor - PhD / In this century most major medical advances have resulted in part from research on animals and non-human primates such as the African green monkey and therefore often serve as a critical link between basic research and human clinical application. Due to its close evolutionary relationship to humans, the African green monkey is known to be an excellent and most sought after models for studies of human cardiovascular disease (CVD). While the human genome project and some others related to model organisms are very well advanced or even complete, little sequence information has been acquired for the African green monkey. Given the importance of this species in biomedical research generally and CVD specifically, and the fundamental significance of sequence data, it is critical that this paucity of genome information concerning this specific animal model be addressed in order to better define the molecular basis and to further understand the mechanism of cholesterol metabolism in this species which will also contribute immensely to primatology. There is a growing interest in the role of genetic polymorphisms in predicting susceptibility to disease and responsiveness to drug interventions. Since plasma lipid abnormalities are risk factors for coronary atherosclerosis, determination of these plasma lipid concentrations, especially for genes involved in lipid transport and metabolism may be influenced by genetic variations. In this study, the African green monkey was used as a model to evaluate the effect of niacin on plasma lipids and reverse cholesterol transport by examine gene expression and the influence of several polymorphisms found in genes that are involved in cholesterol metabolism in humans. A survey of genetic variation spanning ten prioritised “candidate” genes was conducted, all of which are known to produce proteins that play key roles in the reverse cholesterol pathway (RCT), and in the homeostatic regulation of blood lipid profiles related to cardiovascular health and disease. everse transcription polymerase chain reaction (RT-PCR) was used to evaluate mRNA expression of those “candidate” genes. Twenty two coincident singlenucleotide polymorphisms (cSNPs), reported to play a vital role in RCT, were genotyped within these genes. This study’s findings implicate a subset of six of the twenty two genetic variants, spanning five “candidate” genes. To assess possible involvement of these prioritised “candidate” genes and their polymorphisms, biochemical analyses of known risk factors of coronary artery disease such as HDL-C and LDL-C were conducted. Eight healthy African green monkeys were entered in this study of which four were treated with niacin at an escalating dosage. Their mean lipid-lowering response following drug therapy was analysed, compared to those with the same genotype in a control group. Niacin treatment was associated with a considerable reduction in LDL-Cholesterol, up-regulation of HDL synthesis, and increase of apo A-1 levels. Gene expression had minimal effect on niacin treatment, except CYP7A1 which was down-regulated at the same time when considerable change in HDL-C, LDL-C and apoA-1 levels was observed. The presence of CYP7A1:Asn233Ser polymorphism may have played a critical role in metabolising niacin and influencing the up-regulation of HDL-C synthesis in the African green monkey. Although cholesterol lowering alone may explain the anti-atherosclerotic effect of niacin on HDL-C, in this study, gene expression data also shed some light in supporting the hypothesis that genetic variants may influence the expression of genes involved in RCT, which may also have played a role in the anti-atherosclerotic effect of the drug.

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.

Yes / The development of cardiovascular disease (CVD) is the main cause of death among chronic kidney disease (CKD) patients (1). Endothelial injury and dysfunction are critical steps in atherosclerosis, a major CVD (2). Increased production of reactive oxygen species (ROS) has been associated with the pathogenesis of cardiovascular diseases such as atherosclerosis, hypertension and heart failure (3). However, hydrogen peroxide (H2O2) modulates endothelial cell function by intricate mechanisms. Ambient production of O2.− and subsequently H2O2 at low levels, maintained via basal activity of pre-assembled endothelial NAD (P) H oxidases (4). Endothelial cells play an important regulatory role in the circulation as a physical barrier and as a source of a variety of regulatory substances. Dysfunction of the vascular endothelium is thus leading to atherosclerosis which is characterised by overexpression of adhesion molecule expression, comprising vascular cell adhesion molecule 1(VCAM1). This adhesion molecule has been found to be up-regulation in human atherosclerotic lesions. The aim of this study is to evaluate the effect of H2O2 on the endothelial cells adhesion molecules expression. Primary cultures of Human Umbilical Vascular Endothelial Cells (HUVECs) will be maintained in endothelial growth medium supplemented with penicillin-streptomycin and supplement mix of fetal calf serum in a 37C humidified incubator in an atmosphere of 5% v/v CO2. HUVECs will be treated with in the presence and absences of 50 μM of H 2O2 for 2, 6, 12 and 24 h. Intracellular superoxide anion production in HUVECs will be detected by using p-Nitro Blue Tetrazolium (NBT) assay to demonstrate whether H2O2 induce the generation of superoxide anions intracellularly in HUVECs. The formation of blue formazan will be measured spectrophotometrically at 570 nm. Total RNA will be extracted from non-treated and treated cells and RNA quantity and quality will be checked by OD260/280 measurements. VCAM-1 mRNA expression will be assessed using RT-PCR. Our results show that H2O2 could potentially significantly induce EC activation through increased mRNA expression of ICAM-1 adhesion molecules in cultured HUVECs. Treatment with N-acetyl cysteine (NAC) (bulk/nano form) could significantly attenuate the effect of H2O2 administration on adhesion molecule protein expression. This strongly suggests the role of ROS in the endothelial cell damage sustained. Future work is to find reliable methods to test endothelial function. Non-invasive studies such as brachial ultrasound testing are also needed to determine its predictive value as a potential predictor for cardiovascular disease.

The life expectancy (LE) gap experienced by Aboriginal and Torres Strait Islander peoples in one of Australians most enduring health divides. Whilst there are many likely reasons, cardiovascular diseases (CVD) stand as the primary contributor. In particular, it is the almost ten-fold higher mortality from CVD at young ages that distinguishes this epidemic. The reasons for this disparity remain incompletely understood. Current research has focused on the likely contribution of traditional risk factor burdens in Aboriginal people, who demonstrate higher levels of smoking, obesity, hypertension and dyslipidaemia. Less attention has focused on the potential contribution of disadvantage and its interplay with psychosocial factors. Research on the psychosocial determinants of health, particularly in relation to CVD, has a long pedigree. Social context, particularly inequality between individuals, has assumed its rightful place at the forefront of our understandings of population levels of disease. Among them, socioeconomic position [SEP] and depression are the most robust, and most widely researched. They have not been adequately explored in the context of Aboriginal Australians, nor has the manner in which culture shapes, sustains or transforms disadvantage and psychosocial stress been outlined. The objective of the Men Hearts and Minds (MHM) Study was to identify the possible ways in which social disadvantage may lead to CVD in Aboriginal men in Central Australia and consider the role of psychosocial factors in modifying or mediating this relationship. This required a detailed and multi-disciplinary plan of research, covering the epidemiology of mental illness and chronic diseases, biomedical science, ethnographic field work and qualitative methodologies. Stage I required the development of measurement tools for exploring depression, stress, resilience, mastery and socioeconomic indicators that were valid and robust for use with Aboriginal men within Central Australia. This involved multi-stage qualitative techniques, engaging Aboriginal men, traditional healers (Ngangkari Tjuta) and mental health experts, to define the expressions and construction of mental illness in Aboriginal men. Depression existed, was recognizable, common, and had profound impacts on the social, emotional and physical well-being of Aboriginal men. ‘Worry’ was the most recognisable element, and the principle contributor to depression in Aboriginal men. Much of this was focused on the increasingly heavy and cumulative social and cultural burdens experienced throughout Aboriginal men’s lives, and manifest as a sense of inner turmoil and questioning of self, and of feelings of disconnectedness from all the things of critical importance within their lives. Kurunpa [spirit] was seen as the foundation of vitality and was critical to the physical, emotional and spiritual well-being of Aboriginal people. These findings were then used to interrogate existing psychological testing tools and develop novel measures to explore the interplay of SEP, stress and depression. These tools were then used in a community dwelling sample of Aboriginal men in Central Australia to explore the interaction of SEP, stress and depression and their potential contribution to CVD risk. In total 186 Aboriginal men across urban and remote community settings were assessed. Almost 40% of the sample had elevated depressive symptoms. Depression was highly correlated with standard measures of distress and inversely with mastery. Newly created measures, assessing Chronic Stress, the ‘Sense of Injury’ and deprivation, were highly correlated, reliable and fulfilled many validity criteria. There was a high level of cardiovascular risk, which was related to a number of psychosocial factors, particularly depression. Major depression was over 9 times as common in individuals with prevalent CVD. Cardiovascular risk was patterned across social strata, but not evident with the use of routine measures of SEP. Psychosocial factors modified the observed social gradient. In those with high chronic stress, the social gradient in CVD risk gradient was amplified. This pattern was mirrored in those who had been removed or had family forcible removed. Depression was correlated with a number of atherogenic pathways. Smokers were more likely to be depressed, and depression was strongly related to obesity. Individual with high depression scores were more than 20 times more likely to have a Body Mass Index >30. The interplay between the Autonomic Nervous System (ANS) (estimated with measures of Heart Rate Variability) and the Hypothalamic Pituitary Adrenal (HPA) axis (as measured according to obesity) highlights the interconnections across atherogenic pathways and may frame the cardiometabolic risk and psychosocial pathways to cardiovascular disease in this sample. The phenomenology of cumulative stress, distress and depression within the narratives of Aboriginal men constructed illness as a consequence of the ongoing fight to maintain balance - physically, emotionally and spiritually. From both a social and biological perspective, the construction of depression and heart disease as a consequence of cumulative chronic stress among Aboriginal men was supported in the findings of this work.

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.

Non-communicable disease (NCD) (particular by cardiovascular disease, CVD) is the leading cause of death in most countries including OECD countries. WHO (World Health Organization, 2002) has emphasized the trend of disease patterns shifting from communicable diseases towards to non-communicable diseases globally. However, globalization drives economic activities vigorously and alternates work conditions, such as prolonger or irregular working time, changing patterns of job. And then, more sweating, stress and occupational safety of labors after globalization were noted by many worldwide scholars. ¡§Karoshi¡¨ (death from overwork) is a controversial issue of occupational matters in these years all over the world. According to past empirical literatures, CVD was also the major medical cause of death from overwork. Hence, we collect panel data of CVD mortality, working hours of labor and KOF index of globalization covering 19 OECD countries from a period of 1980 to 2007, and measure by panel cointegration analysis and fully modified OLS (FMOLS) to estimate the reciprocal relationship among these variables. The evidence findings show significant influence on CVD mortality if increasing working hours of labor, especially at age groups of 15 to 24 year. While significant effect on CVD mortality through by globalization was found at age group 25 to 54 year and elders, particular in social globalization.

<p>Leukotrienes are arachidonic acid derivatives long known for their inflammatory properties and their involvement with a number of human diseases, most notably asthma. Recently, leukotriene-based inflammation has also been implicated in atherosclerosis: ALOX5AP and LTA4H, two genes in the leukotriene biosynthesis pathway, have been associated with various cardiovascular disease (CVD) phenotypes. To assess the role of the leukotriene pathway in CVD pathogenesis, we performed genetic association studies of ALOX5AP and LTA4H in a non-familial data set of early onset coronary artery disease. Our results support a modest role for the leukotriene pathway in atherosclerosis pathogenesis, reveal important genomic interactions within the pathway, and suggest the importance of using pathway-based modeling for evaluating the genomics of atherosclerosis susceptibility. Motivated by this need, we investigated the statistical properties of a class of matrix-based statistics to assess epistasis. We simulated multiple two-variant disease models with haplotypes to gain an understanding of pathway interactions in terms of correlation patterns. Our goal was to detect an interaction between multiple disease-causing variants by means of their linkage disequlibrium (LD) patterns with other haplotype markers. The simulated models can be summarized into three categories: 1. No epistasis in the presence of marginal effects and LD; 2. Epistasis in the presence of LD and no marginal effects; and 3. Epistasis in the presence marginal effects and LD. We then assessed previously introduced single-gene methods that compare whole matrices of Single Nucleotide Polymorphism (SNP) LD between two samples. These methods include comparing two sets of principal components, a sum-of-squared-differences comparing pairwise LD, and a contrast test that controls for background LD. We also considered a partial least-square (PLS) approach for modeling gene-gene interactions. Our results indicate that these measures can be used to assess epistasis as well as marginal effects under certain disease models. Understanding and quantifying whole-gene variation and association to disease using multiple SNPs remains a difficult task. Providing a single statistical measure per gene will facilitate combining multiple types of genomic data at a gene-level and will serve as an alternative approach to assess epistasis in genome-wide association studies. The matrix-based measures can also be used in pathway ascertainment tools that require scores on a gene-level.</p> / Dissertation

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.

Hypertension, a medical condition, predisposes to other cardiovascular diseases, and can be impacted by the social determinants of health (SDOH). Self-measured blood pressure monitoring (SMBP) is an evidence-based approach to hypertension control, but not much is known about the influence of SDOH on SMBP. This dissertation aims to: 1) highlight the SDOH factors whose relationship with SMBP have been explored in research studies; 2) examine the relationship between SDOH and SMBP among United States (U.S.) adults with high blood pressure; and 3) examine the current state of SMBP in the U.S., highlight policy implications from the empirical study and provide recommendations. Aims 1 and 2 were informed by an adapted SDOH framework, which comprised of upstream structural determinants, and downstream intermediary determinants. Aim 1 was achieved via a scoping review of studies across three databases following the PRISMA-SCR checklist. Aim 2 was achieved via a cross-sectional analysis of data from adult respondents to the 2019 Behavioral Risk Factor Surveillance System, with self-reported hypertension. Bivariate and Multiple Logistic regression analyses were conducted. Aim 3 involved a literature scan on policy concerning SMBP, highlighting the policy implications of findings from the empirical study, and providing recommendations for policy/practice. For aim 1, findings suggest that research studies examined the relationship of relatively more structural determinants, than the few, but highly significant intermediary determinants, with SMBP. For aim 2, looking at the structural determinants, males and those who identify as Black and other minority racial groups were more likely to report SMBP. For intermediary determinants, respondents who consumed fruits, vegetables, and exercised were likely to report SMBP, while those who smoke, who drink, and those with poor mental health days were less likely to report SMBP. Respondents with health coverage and whose provider recommended SMBP were likely to report SMBP use. Those ≥65 years were more likely to report SMBP. For aim 3, I recommend that the Centers for Medicare and Medicaid Services lead policy efforts on SMBP reimbursements. Also, healthcare practices should strengthen their technological infrastructure e.g., telehealth to promote access, and Electronic Health Records to promote efficient data collection and tracking.

No description available.