Prolonged QT interval and lipid alterations beyond β-oxidation in very long-chain acyl-CoA dehydrogenase null mouse hearts.

Abstract

Patients with very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency frequently present cardiomyopathy and heartbeat disorders. However, the underlying factors, which may be of cardiac or extra cardiac origins, remain to be elucidated. In this study, we tested for metabolic and functional alterations in the heart from 3- and 7-mo-old VLCAD null mice and their littermate counterparts, using validated experimental paradigms, namely, 1) ex vivo perfusion in working mode, with concomitant evaluation of myocardial contractility and metabolic fluxes using (13)C-labeled substrates under various conditions; as well as 2) in vivo targeted lipidomics, gene expression analysis as well as electrocardiogram monitoring by telemetry in mice fed various diets. Unexpectedly, when perfused ex vivo, working VLCAD null mouse hearts maintained values similar to those of the controls for functional parameters and for the contribution of exogenous palmitate to β-oxidation (energy production), even at high palmitate concentration (1 mM) and increased energy demand (with 1 μM epinephrine) or after fasting. However, in vivo, these hearts displayed a prolonged rate-corrected QT (QTc) interval under all conditions examined, as well as the following lipid alterations: 1) age- and condition-dependent accumulation of triglycerides, and 2) 20% lower docosahexaenoic acid (an omega-3 polyunsaturated fatty acid) in membrane phospholipids. The latter was independent of liver but affected by feeding a diet enriched in saturated fat (exacerbated) or fish oil (attenuated). Our finding of a longer QTc interval in VLCAD null mice appears to be most relevant given that such condition increases the risk of sudden cardiac death.

• Authors: Roselle Gélinas, Julie Thompson-Legault, Bertrand Bouchard, Caroline Daneault, Asmaa Mansour, Marc-Antoine Gillis, Guy Charron, Victor Gavino, François Labarthe, Christine Des Rosiers
• Journal: American journal of physiology. Heart and circulatory physiology (Am J Physiol Heart Circ Physiol) Vol. 301 Issue 3 Pg. H813-23 (Sep 2011) ISSN: 1522-1539 [Electronic] United States
• PMID: 21685264 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Fish Oils
• Triglycerides
• Docosahexaenoic Acids
• Palmitic Acid
• Acyl-CoA Dehydrogenase, Long-Chain

Topics

• Acyl-CoA Dehydrogenase, Long-Chain (deficiency, genetics)
• Age Factors
• Aging
• Analysis of Variance
• Animals
• Congenital Bone Marrow Failure Syndromes
• Disease Models, Animal
• Docosahexaenoic Acids (metabolism)
• Electrocardiography, Ambulatory
• Fish Oils (administration & dosage, metabolism)
• Heart Conduction System (physiopathology)
• Lipid Metabolism (genetics)
• Lipid Metabolism, Inborn Errors
• Liver (metabolism)
• Long QT Syndrome (enzymology, genetics, physiopathology, prevention & control)
• Male
• Metabolism, Inborn Errors (complications, enzymology, genetics, physiopathology)
• Mice
• Mice, 129 Strain
• Mice, Inbred C57BL
• Mice, Knockout
• Mitochondrial Diseases (complications, enzymology, genetics, physiopathology)
• Muscular Diseases (complications, enzymology, genetics, physiopathology)
• Myocardial Contraction
• Myocardium (enzymology)
• Oxidation-Reduction
• Palmitic Acid (metabolism)
• Perfusion
• Telemetry
• Triglycerides (metabolism)