Genetics, statins, and lipid metabolism in cardiovascular disease

Aim of this thesis was to investigate pharmacogenetic effects on response to statin treatment and the genetics of lipid metabolism and cardiovascular disease. In chapter 4 the first results of the Genomic investigation of Statin Therapy (GIST) consortium are presented. We identified and validated two new GWAS loci to be associated with LDL-cholesterol response after statin treatment. In addition, we confirmed two previous identified loci. In chapter 5 we showed that we were not able to identify any loci associated with differential event reduction after statin therapy within the PROSPER study. The results presented in chapter 8 show that even at old age a genetic predisposition to high LDL-cholesterol is a risk factor for mortality. The results of this thesis show that currently the possibilities to personalize statin treatment based on genetic variants is limited. New research methods will hopefully give new opportunities to improve cardiovascular disease treatment and give more insight into the biological mechanisms of statin treatment.UBL - phd migration 201

Pharmacogenetic GWAS meta-analysis of LDL cholesterol response to statins

Cardiolog

Study protocol: a randomised controlled trial on the clinical effects of levothyroxine treatment for subclinical hypothyroidism in people aged 80 years and over

Background: Subclinical hypothyroidism is common in older people and its contribution to health and disease needs to be elucidated further. Observational and clinical trial data on the clinical effects of subclinical hypothyroidism in persons aged 80 years and over is inconclusive, with some studies suggesting harm and some suggesting benefits, translating into equipoise whether levothyroxine therapy provides clinical benefits. This manuscript describes the study protocol for the Institute for Evidence-Based Medicine in Old Age (IEMO) 80-plus thyroid trial to generate the necessary evidence base. Methods: The IEMO 80-plus thyroid trial was explicitly designed as an ancillary experiment to the Thyroid hormone Replacement for Untreated older adults with Subclinical hypothyroidism randomised placebo controlled Trial (TRUST) with a near identical protocol and shared research infrastructure. Outcomes will be presented separately for the IEMO and TRUST 80-plus groups, as well as a pre-planned combined analysis of the 145 participants included in the IEMO trial and the 146 participants from the TRUST thyroid trial aged 80 years and over. The IEMO 80-plus thyroid trial is a multi-centre randomised double-blind placebo-controlled parallel group trial of levothyroxine treatment in community-dwelling participants aged 80 years and over with persistent subclinical hypothyroidism (TSH ≥4.6 and ≤ 19.9 mU/L and fT4 within laboratory reference ranges). Participants are randomised to levothyroxine 25 or 50 micrograms daily or matching placebo with dose titrations according to TSH levels, for a minimum follow-up of one and a maximum of three years. Primary study endpoints: hypothyroid physical symptoms and tiredness on the thyroid-related quality of life patient-reported outcome (ThyPRO) at one year. Secondary endpoints: generic quality of life, executive cognitive function, handgrip strength, functional ability, blood pressure, weight, body mass index, and mortality. Adverse events will be recorded with specific interest on cardiovascular endpoints such as atrial fibrillation and heart failure. Discussion: The combined analysis of participants in the IEMO 80-plus thyroid trial with the participants aged over 80 in the TRUST trial will provide the largest experimental evidence base on multimodal effects of levothyroxine treatment in 80-plus persons to date

A refined radio-telemetry technique to monitor right ventricle or pulmonary artery pressures in rats: a useful tool in pulmonary hypertension research

Implantable radio-telemetry methodology, allowing for continuous recording of pulmonary haemodynamics, has previously been used to assess effects of therapy on development and treatment of pulmonary hypertension. In the original procedure, rats were subjected to invasive thoracic surgery, which imposes significant stress that may disturb critical aspects of the cardiovascular system and delay recovery. In the present study, we describe and compare the original trans-thoracic approach with a new, simpler trans-diaphragm approach for catheter placement, which avoids the need for surgical invasion of the thorax. Satisfactory overall success rates up to 75% were achieved in both approaches, and right ventricular pressures and heart and respiratory rates normalised within 2 weeks. However, recovery was significantly faster in trans-diaphragm than in trans-thoracic operated animals (6.4 ± 0.5 vs 9.5 ± 1.1 days, respectively; p < 0.05). Stable right ventricular pressures were recorded for more than 4 months, and pressure changes, induced by monocrotaline or pulmonary embolisms, were readily detected. The data demonstrate that right ventricular telemetry is a practicable procedure and a useful tool in pulmonary hypertension research in rats, especially when used in combination with echocardiography. We conclude that the described trans-diaphragm approach should be considered as the method of choice, for it is less invasive and simpler to perform

Preferences about Future Alzheimer’s Disease Treatments Elicited through an Online Survey Using the Threshold Technique

Background: Treatments aiming at slowing down the progression of Alzheimer’s disease (AD) may soon become available. However, information about the risks that people are willing to accept in order to delay the progression of the disease is limited.Objective: To determine the trade-offs that individuals are willing to make between the benefits and risks of hypothetical treatments for AD, and the extent to which these trade-offs depend on individuals’ characteristics and beliefs about medicines.Design: Online, cross-sectional survey study.Setting: Population in the UK. Public link to the survey available at the websites of Alzheimer’s Research UK and Join Dementia Research.Participants: Everyone self-reported ≥18 years old was eligible to participate. A total of 4384 people entered the survey and 3658 completed it.Measurements: The maximum acceptable risks (MARs) of participants for moderate and severe adverse events in exchange for a 2-year delay in disease progression. The risks were expressed on ordinal scales, from &lt;10% to ≥50%, above a pre-existing risk of 30% for moderate adverse events and 10% for severe adverse events. We obtained the population median MARs using log-normal survival models and quantified the effects of individuals’ characteristics and beliefs about medicines in terms of acceleration factors.Results: For the moderate adverse events, 26% of the participants had a MAR ≥50%, followed by 25% of the participants with a MAR of 10 to &lt;20%, giving an estimated median MAR of 25.4% (95% confidence interval [CI] 24.5 to 26.3). For the severe adverse events, 43% of the participants had a MAR &lt;10%, followed by 25% of the participants with a MAR of 10 to &lt;20%, resulting in an estimated median MAR of 12.1% (95%CI 11.6 to 12.5). Factors that were associated with the individuals’ MARs for one or both adverse events were age, gender, educational level, living alone, and beliefs about medicines. Whether or not individuals were living with memory problems or had experience as a caregiver had no effect on the MARs for any of the adverse events.Conclusion: Trade-offs between benefits and risks of AD treatments are heterogeneous and influenced by individuals’ characteristics and beliefs about medicines. This heterogeneity should be acknowledged during the medicinal product decision-making in order to fulfil the needs of the various subpopulations.</p

Probing Mechanical Properties of Graphene with Raman Spectroscopy

The use of Raman scattering techniques to study the mechanical properties of graphene films is reviewed here. The determination of Gruneisen parameters of suspended graphene sheets under uni- and bi-axial strain is discussed and the values are compared to theoretical predictions. The effects of the graphene-substrate interaction on strain and to the temperature evolution of the graphene Raman spectra are discussed. Finally, the relation between mechanical and thermal properties is presented along with the characterization of thermal properties of graphene with Raman spectroscopy.Comment: To appear in the Journal of Materials Scienc