Changes in cardiac energy metabolic pathways in overweighed rats fed a high-fat diet

Background Heart produces ATP through long-chain fatty acids beta oxidation. Purpose To analyze whether in ventricular myocardium, high-fat diet may modify the expression of proteins associated with energy metabolism before myocardial function was affected. Methods Wistar Kyoto rats were divided into two groups: (a) rats fed standard diet (control; n = 6) and (b) rats fed high-fat diet (HFD; n = 6). Proteins from left ventricles were analyzed by two-dimensional electrophoresis, mass spectrometry and Western blotting. Results Rats fed with HFD showed higher body weight, insulin, glucose, leptin and total cholesterol plasma levels as compared with those fed with standard diet. However, myocardial functional parameters were not different between them. The protein expression of 3-ketoacyl-CoA thiolase, acyl-CoA hydrolase mitochondrial precursor and enoyl-CoA hydratase, three long-chain fatty acid b-oxidation-related enzymes, and carnitine-O-palmitoyltransferase I was significantly higher in left ventricles from HFD rats. Protein expression of triosephosphate isomerase was higher in left ventricles from HFD rats than in those from control. Two a/b-enolase isotypes and glyceraldehyde-3-phosphate isomerase were significantly increased in HFD rats as compared with control. Pyruvate and lactate contents were similar in HFD and control groups. Expression of proteins associated with Krebs cycle and mitochondrial oxidative phosphorylation was higher in HFD rats. Conclusions Expression of proteins involved in left ventricle metabolic energy was enhanced before myocardial functionality was affected in rats fed with HFD. These findings may probably indicate higher cardiac energy requirement due to weight increase by HFD.