Cardiac Lipotoxicity and Ceramide Metabolism in Heart Failure
NIH undColumbia University New York
The prevalence of heart failure (HF) is increasing throughout the world with high morbidity and mortality. Our previous work has shown accumulation of the toxic lipid intermediates ceramide and diacylglycerol in failing human myocardium and that these toxic lipids induce transcriptional changes, impaired cellular energy metabolism and inhibit insulin signaling. The central hypothesis of this application is that lipotoxic accumulation of long-chain ceramide species contributes to structural and functional myocardial changes in HF. We hypothesize that lipotoxicity is a key means of myocardial dysfunction but that distinct characteristics exist defined by the underlying cardiomyopathy. We will analyze the myocardial lipid composition using LC/MS techniques. We also will study the impact of mechanical unloading through left ventricular assist device (LVAD) placement on myocardial metabolic derangements (AIM 1). Further, we will analyze pathways controlling gene and microRNA expression and link these to the results of the lipid composition analyses (AIM 2). Finally, we will analyze the cardiac lipid composition in animal models of human ischemic and non-ischemic cardiomyopathies and test whether pharmacologic and genetic inhibition of the de novo and salvage pathway of ceramide synthesis affects long-chain ceramide accumulation and progressive cardiac remodeling (AIM 3). In achieving the goals of this proposal, we will expand the understanding of key mechanisms underlying myocardial structural and functional derangements in HF. These studies will define new molecular and functional targets in patients with HF. The proposed work will, therefore, lay critical groundwork for broader clinical goals to define and enhance therapeutic strategies to modify molecular and transcriptional patterns of cardiac metabolism in HF.