Cardiac manifestations of mitochondrial disease - incidence, mechanisms and treatment. (360G-Wellcome-090748_Z_09_Z)

Mitochondrial DNA (mtDNA) diseases affect more than 1 in 10,000 people and exhibit variable clinical features. Cardiac manifestations are common and include conduction abnormalities and cardiomyopathies. In patients with mitochondrial disease, I wish to: 1. determine the incidence and nature of cardiac manifestations; 2. understand the molecular mechanisms linking different defects to different cardiomyopathies; 3. demonstrate the effect of early intervention on energy metabolism. To determine the incidence of cardiac manifestations, I will have access to the MRC Mitochondrial Disease Patient Cohort (UK). Clinical assessment will be performed using ECG, echocardiography and Holter monitoring. To understand the molecular mechanisms underlying specific cardiac defects, I will use a bank of fresh-frozen cardiac tissue from patients with different mtDNA mutations. I will use different histochemical, immunohistochemical and molecular genetic techniques to explore the nature of the molecular defect in individual cardiomyocytes from patients with specific genetic defects. Magnetic resonance imaging and 31P spectroscopy will be used to determine the incidence of early cardiomyopathic changes and bioenergetic defects due to different mtDNA mutations. I will repeat studies following 3 months of treatment with energy-sparing agents to establish whether these changes are reversible and whether early medical intervention in high risk groups is justified.