The endothelial nitric oxide synthase (eNOS) co-factor tetrahydrobiopterin (BH4) has been shown to play a pivotal role in maintaining endothelial function in experimental vascular disease models. In BH4-deficient states, eNOS becomes enzymatically ‘uncoupled’, generating reactive oxygen species instead of nitric oxide, thus promoting endothelial dysfunction. In humans with coronary artery disease (CAD), higher vascular BH4 levels have been shown to be associated with improved endothelial function, and genetic variation in endogenous BH4 synthesis has implicated a causal role. Accordingly, BH4 has been proposed as a potential therapeutic target in vascular disease states. The work in this thesis aims to further elucidate the roles of exogenous and endogenous BH4 in humans. In a randomised, placebo-controlled clinical trial of oral BH4 therapy in patients with CAD, exogenous BH4 had no effect on endothelial function or vascular oxidative stress. Subsequent pharmacokinetic and pharmacodynamic analysis revealed that oral BH4 significantly augmented BH4 levels in plasma and in venous tissue (but not in arterial tissue), but also increased levels of the oxidation product dihydrobiopterin (BH2), which lacks eNOS cofactor activity. Thus, there was a null effect on overall biopterin redox status. To further understand the mechanics of exogenous BH4 oxidation, ex vivo studies of human blood and vascular tissue demonstrated that exogenous BH4 is very rapidly oxidised to BH2; co-administration with an antioxidant had only a modest effect on preventing BH4 oxidation in blood, with no beneficial effect on biopterin redox state in the vasculature. Finally, using a “Mendelian randomisation” approach, I studied the effects of a haplotype of GCH1 (the gene encoding the rate limiting enzyme in BH4 synthesis) on endogenous BH4 bioavailability and vascular function in healthy individuals. In patients with CAD, this haplotype has been associated with decreased BH4 bioavailability and eNOS uncoupling, however in healthy individuals the haplotype exerted no significant effect, likely due to reduced inflammatory stimulation of GCH1.

Background: Acute myocardial infarction (AMI) is a major public health concern. There are limited recent national-level population-based epidemiological data on AMI in England. As a result, the current burden of disease is difficult to quantify. Aim: This thesis addresses gaps in knowledge on AMI in England. It aims to provide a comprehensive analysis of AMI epidemiology over the last decade. Methods: This is a population-based study using person-linked routine hospital and mortality data for England for the period from 1 April 1998 to 31 March 2008. Main outcome measures include: trends in event rate, case fatality, and mortality for AMI, as well as trends in characteristics of, and hospital care for, the AMI patient population between 1999 and 2007; rates of occurrence and case fatality for first and recurrent AMI in 2007; and five-year survival and risk of a second AMI for 2003 to 2007. Results: Total age-standardised AMI mortality rate fell by around half, while the age-standardised event rate and case fatality rate each declined by around one third between 1999 and 2007. Approximately half of the decline in AMI mortality was attributed to a decline in event rate and half to improved survival. During the 2000s, the hospitalised AMI patient population became increasingly elderly, presented with more comorbidities, underwent more revascularisation procedures, and spent less time in hospital. In 2007, approximately 90,000 AMIs occurred in England, of which around one third were fatal, one in seven were reinfarctions, and three quarters were AMIs in those aged 65 years and older. Among 30-day survivors of a first AMI, around one in three men and one in four women died within five years, and about one in eight men and one in six women experienced a second AMI in the same time period. Conclusions: There have been substantial improvements in AMI occurrence, survival, and mortality over the last decade in England. This was driven by improvements in prevention and acute medical treatment. The results in this thesis emphasise the importance of both.

Background: Excess adiposity, diabetes mellitus, and ischaemic heart disease are common important causes of morbidity and premature mortality in postmenopausal women in the UK. A large amount of data exists on known risk factors for these conditions, and for risk factors men and women share there is little evidence to suggest sex-based differences. It has been suggested that factors unique to women (such as parity and breastfeeding) may also influence risk. The nature of the relationship between childbearing and these conditions remains to be clarified. In this thesis I explore the association between women’s childbearing histories and their adiposity, and risk of diabetes or ischaemic heart disease after the menopause, to provide evidence on the character, repeatability and public health relevance of the associations. Aim: To explore the hypothesis that childbearing (specifically parity and breastfeeding) is associated with women’s body weight and risk of excess adiposity, and also with women’s risk of diabetes mellitus, and ischaemic heart disease after the menopause. Methods: Data are analysed from a large population-based cohort of middle-aged UK women recruited in 1996 to 2001 (the Million Women Study) with complete childbearing information, and who had baseline anthropometry, and were followed for incident diabetes or ischaemic heart disease through repeat survey questionnaires, hospital admission records, and central registry databases. Results: In a large ethnically homogeneous population of postmenopausal UK women increasing parity was associated with an increase in BMI, however this increase was offset in women who breastfed. The associations between parity, breastfeeding and BMI were of a similar order of magnitude to established risk factors known to be associated with BMI, for example smoking, and physical activity. The associations between childbearing and women’s risk of diabetes mellitus after the menopause appear to be largely due to the effects of childbearing on maternal BMI. There is only limited evidence to suggest a direct effect of childbearing on women’s risk of diabetes after the menopause. There is statistically significant evidence of an association between childbearing and women’s risk of ischaemic heart disease after the menopause. Parity was associated with a modest increase in risk whereas breastfeeding was associated with a small decrease in risk, however the effects were small in comparison to known important risk factors. Conclusions In a large population of UK women childbearing was found to have a persistent influence on women’s mean BMI after the menopause, and through this postmenopausal risk of diabetes mellitus. Childbearing was also found to be mod-estly associated with women’s risk of ischaemic heart disease after the menopause.

The advent of hyperpolarized magnetic resonance (MR) has provided new potential for real-time visualization of in vivo metabolic processes. The aim of the work in this thesis was to use hyperpolarized substrates to study rapid metabolic processes occurring in the healthy and diseased rat heart. Initial work, described in Chapter 2, optimized the hyperpolarization process to reproducibly generate tracers. Chapter 3 describes use of hyperpolarized 1-13C-pyruvate to investigate in vivo flux through the regulatory enzyme pyruvate dehydrogenase (PDH). Cardiac PDH activity was altered in several physiological and pathological states, namely fasting, type 1 diabetes, and high-fat feeding, and in vivo flux through PDH was measured using hyperpolarized MR. These measurements correlated with measurements of in vitro PDH activity obtained using a validated biochemical assay. The work in Chapter 4 investigated the physiological interaction between hyperpolarized tracer and cardiac tissue. The effect of hyperpolarized 1-13C-pyruvate concentration on its in vivo metabolism was analyzed using modified Michaelis-Menten kinetics. It was found that hyperpolarized MR could non-invasively follow mechanisms of metabolic regulation, in addition to reporting enzyme activity. In Chapter 5, hyperpolarized MR was incorporated into the isolated perfused rat heart. 1-13C-pyruvate in normal and ischaemic hearts revealed significant differences in lactate metabolism, and provided the foundation for a novel intracellular pH probe. Infusion of 2-13C-pyruvate in the isolated rat heart enabled the first real-time visualization of Krebs cycle intermediates. In summary, the work in this thesis has highlighted the potential of hyperpolarized MR to reveal novel information on heart disease.

Hospital readmissions are a source of reduced payment as mandated by the Centers for Medicare and Medicaid Services as part of the Affordable Care Act (ACA). The number of dollars used for hospital readmissions has sky rocketed above $17 million for heart failure alone. The changes in the ACA reimbursement guidelines has put stress on many hospitals as they are facing reduced income, increased use of resources, and increased length of stay. This project evaluated the implementation of Project BOOST, its components, and their predictability for hospital readmission. Sample groups were evaluated both pre- and post-implementation of Project BOOST, which included individuals aged 18 and older, who were of Anglo, Hispanic or Native American descent, and living in Northern Arizona. A retrospective chart review was performed and descriptive and predictive statistics were used to analyze obtained data. Patients with cardiovascular disease admitted to the study hospital have high risks for readmission, such as problem medications, polypharmacy, psychological Issues, and principal diagnoses. Integrating elements from Project BOOST significantly decreased 30-day hospital readmissions. Data from this study revealed a statistically significant reduction in 30-day hospital readmission rates from 22% in the pre-intervention period to just 4% in the post-intervention period. Patients who did not receive the risk assessment tool were 14 times more likely to be readmitted to the hospital within 30 days of the index hospitalization.

Background: There is mounting evidence to indicate that periodontitis may be a risk factor for cardiovascular disease (CVD). Periodontitis may be linked to CVD as either an etiologic mechanism or a predisposing factor that can hasten disease progression. Proinflammatory cytokines, elevated fibrinogen, and platelet aggregation are all potential mechanisms. The purpose of this study is to compare and review the serological differences in subjects with severe periodontitis, some of which involve established risk factors for atherosclerosis, particularly heightened C-reactive protein levels. Methods: A total of 184 subjects, comprising of two periodontal subgroups, non-periodontal (NP = 91) and generalized aggressive periodontitis (SP = 93), had serum evaluated for C-reactive protein (CRP) levels using a high sensitive ELISA test. The CRP levels were compared against clinical and demographical data to include race, age, gender, number of teeth, probing depth, attachment level, bleeding index, plaque index, and gingival index. Results: After adjusting for potential confounding variables, probing depth (p Conclusion: Pocket depth is significantly related to elevated levels of CRP, which is why it is imperative to treat periodontal pockets. This study may provide a possible link between CRP and periodontal disease, but a causal relationship cannot be inferred.

Background: Hypertension is a major public health concern for African American women. Many studies have shown a greater prevalence of hypertension, as well as physical inactivity, excess weight, and diabetes, in African Americans. Objective: To determine if differences in eating patterns, as measured by Healthy Eating Index (HEI) scores, between African American women and other women in the United States are associated with hypertension. Methods: Data were extracted from the Third National Health and Nutrition Examination Survey (NHANESIII). The sample included 31,189,534 women aged 45 years or greater after survey weights were applied. The majority was White (86.1 %); minority groups included African Americans (10.5%) and Mexican Americans (3.4%). Women were considered to have hypertension if they reported that a doctor diagnosed them. Other predictor variables included age, body mass index, income, education, marital status, residence, health insurance coverage, regu1a.r source of care, smoking history, hypercholesterolemia, history of myocardial infarction, attempted weight loss, and physical activity level. The Cochran Mantel Haenszel (CMH) statistic and logistic regression were used to determine the magnitude of the association of study variables with the outcome. Results: African American women were more likely to have hypertension than White and Mexican American women. Diet, based on the HE1 score, was significantly related to the development of hypertension (CMH chi-square = 428.39, p-value = Conclusions: These findings provide further support the need to established interventions that target this population. The key to prevention is education and promotion of healthier eating habits.

Sudden cardiac death represents one of the leading causes of death worldwide, with the majority of these deaths caused by arrhythmias derived from ischæmic events. However, the mechanisms leading from ischæmia to re-entry, arrhythmia and eventual death are poorly understood. Furthermore, variability in the action potential of cardiac tissue, while important in determining arrhythmic risk, is only recently being addressed in computational modelling, with little known about the causes and mechanisms underlying it, nor regarding its evolution in response to pathological conditions such as ischæmia. This dissertation investigates the causes of variability in the repolarisation of the action potential of the rabbit ventricular myocyte, and the response of this variability to ischæmia. The effect of variability in ion channel conductances is investigated by means of a complete search of the parameter space revealed by simultaneous variation in multiple parameters describing ion channel conductances in computational models of the rabbit ventricular action potential. Rabbit data and models are used in this thesis due to the similarities to human data, both in terms of electrophysiology generally, and the response to ischæmia specifically. The response of two different model frameworks is assessed to determine similarities and differences between model frameworks that are designed to reproduce the same system. Those models producing action potential durations that fall within an experimentally derived range at multiple pacing rates are used to define model populations that thus reproduce experimental variability in repolarisation. These model populations are used to investigate the effects of ischæmic conditions on population variability. Variability is measured not only for action potential duration, but also for other biomarkers commonly implicated in the development of re-entry. The work presented in this dissertation is significant for: (1) presenting a comprehensive study of the effect of simultaneous variation in ion channel conductances, with details regarding the interactions between conductances and how these interactions change depending on the pacing rate; (2) detailed examination of the differences between two models of the same system; (3) production of the largest extant populations reproducing experimentally observed variability in action potential duration; (4) the first time model populations have been used to investigate the effects of ischæmia on variability.

Hypoxia inducible factor-1α (HIF-1α) plays a critical role in the oxygen homeostasis of all metazoans. HIF-1α is a master transcriptional regulator which coordinates the adaptive response to low oxygen tension. Through activation of a plethora of downstream target genes, HIF-1α facilitates oxygenation by promoting angiogenesis and blood vessel dilation, in addition to modulating metabolic pathways to inhibit oxidative phosphorylation and promote glycolytic energy production. Given the critical roles of hypoxia, insufficient blood supply and perturbed energetics in the pathogenesis of cardiovascular disorders, notably ischaemic heart disease, therapeutic modulation of HIF-1α is of significant clinical interest. Previous studies have demonstrated an acute cardioprotective role for both endogenous and supraphysiological HIF-1α signalling in the context of myocardial ischaemia. In contrast, chronic supraphysiological HIF-1α activation in the unstressed heart has been shown to induce cardiac dysfunction. To address the effect of chronic endogenous HIF-1α activation post-myocardial infarction (MI), the present work employed a murine coronary artery ligation (CAL) model in conjunction with temporally-inducible, cardiac-specific deletion of Hif-1α. While CAL surgery successfully modelled myocardial infarction – eliciting substantial adverse cardiac remodelling and contractile dysfunction – there was no evidence of chronic HIF-1α activation by CAL in HIF knockout or control left ventricular samples. In keeping with this, chronic ablation of Hif-1α (from 2 weeks post-CAL) had no discernible additional effect upon cardiac function. Overall, these findings do not support a potential therapeutic role for inhibition of HIF-1α signalling in the chronic phase post-MI. The fundamental tricarboxylic acid (TCA) cycle enzyme fumarate hydratase (FH) converts fumarate to malate. FH deficiency is associated with smooth muscle and kidney tumours which exhibit normoxic HIF signalling due to fumarate accumulation. To investigate the potential for fumarate accumulation to elicit protective HIF signalling, a cardiac-specific Fh1 null mouse was developed through Cre-loxP recombination. Strikingly, despite interruption of the TCA cycle in a highly metabolically demanding organ, cardiac Fh1 null mice were viable, fertile and survived into adulthood, demonstrating the remarkable metabolic plasticity of the heart. However, by 3-4 months Fh1 null mice develop a lethal cardiomyopathy characterised by cardiac hypertrophy, ventricular dilatation and contractile dysfunction. Despite lack of a pseudohypoxic response, Fh1 null hearts did exhibit another phenomenon observed in FH-deficient cancers and also attributed to fumarate accumulation – activation of the nuclear factor (erythroid-derived 2)-like 2 (NRF2) antioxidant pathway. Heterozygous, but not homozygous, somatic deletion of Nrf2 extended the life expectancy of cardiac Fh1 null mice. Exploration of redox status revealed a more reductive environment in Fh1 null hearts than controls. As a corollary, inhibition of the rate limiting enzyme of the pentose phosphate pathway – a major source of cellular reducing equivalents – with dehydroepiandrosterone conferred striking amelioration of the Fh1 null cardiomyopathy, suggesting a possible pathogenic role for reductive stress. While loss of mitochondrial Fh1 activity and subsequent TCA cycle dysfunction likely contribute to the Fh1 null phenotype, the importance of cytosolic FH was unclear. To clarify this, FH was expressed specifically in the cytosol in vivo. This was sufficient to substantially rescue the Fh1 null cardiomyopathy, supporting a role for cytosolic FH disruption in its pathogenesis. Taken together, these findings highlight the potential for reductive stress to contribute to cardiac dysfunction and suggest a function for cytosolic FH in cardiac metabolic homeostasis.

1 Abstract: Title: The importance of primary and secondary prevention of cardiovascular disease Goals: Develop a theoretical basis for the selected topic. Describe the basic principles of primary and secondary prevention, and thus prepare the groundwork for creating questionnaires. Questionnaire compiled to complement the information obtained from the literature on insight into the practice. Confirm or refute the hypotheses chosen on the basis of a questionnaire. Discuss the most frequently occurring phenomena and compare them with the latest reported information. Draw conclusions and recommendations. Method: For the theoretical treatment of the retrieval method was used. I compared the information and inclined to the best proven. The theoretical part resulted in the goals and tasks of work. For the practical part was conducted by questionnaire survey, which has additional information on the issue of primary and secondary prevention. In the end I obtained data compared with information obtained from studying literature. Results: Lack of information on primary and secondary prevention is mainly for young people aged 10-15 years. This trend is accompanied by the deteriorating health situation and the occasional occurrence of the "diseases of civilization", which can produce complications in adulthood....