Pathological hypertrophy and cardiac dysfunction are linked to aberrant endogenous unsaturated fatty acid metabolism

Fig 1. Caloric content and fatty acid composition of diets used in the study. (A-B) The percentage of total calories arising from fats (black), protein (grey), and carbohydrates (white) in the normolipid (Normo) and high unsaturated fat diet (HUFA). (C) The relative abundance of fatty acids in both diets. Fatty acids are organized by degree of unsaturation and carbon length.

Fig 2. Unsaturated fatty acid diet does not prevent upregulation of glycolytic enzyme activity in hypertrophied hearts. (A-C) Activities of hexokinase, phosphofructokinase and lactate dehydrogenase in heart lysates from sham and AS groups fed normolipidic (Normo) or high unsaturated fat diet (HUFA); (D) Citrate synthase activity; (E) Beta hydroxy-acyl CoA dehydrogenase (OHADH). * p<0.05 vs. respective sham (n = 9–13 per group).

Fig 3. Unsaturated fat diet does not reverse down-regulation of fatty acid oxidation (FAO) related genes. Expression of cardiac genes involved in fatty acid oxidation from sham and AS groups fed normolipidic (Normo) or high-unsaturated fat diet (HUFA). (A) PGC1α: peroxisome proliferator-activated receptor gamma coactivator 1-alpha; (B) PPARα: peroxisome proliferator-activated receptor alpha; (C) FAT/CD36: fatty acid translocase; (D) CPT1β: carnitine palmitoyltransferase I beta; (E) MCAD: medium-chain acyl-CoA dehydrogenase. Data presented as fold-change from Sham-Normo. * p<0.05 vs. respective sham, (n = 9–11 per group).

Fig 4. Altered myosin heavy chain or calcium handling protein expression are not affected by high-unsaturated fat diet. Representative image of protein bands from (A) myosin heavy chain (MyHC), sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a), phospholamban (PLB), phosphorylated PLB at serine-16 (pPLB-Ser16), phosphorylated PLB at threonine-17 (pPLB-Thr17), and beta-actin (β-actin). (B) Quantification of the β-MyHC to α-MyHC isoforms. (C) Quantification of the SERCA2 normalized to β-actin. (D) Quantification of pPLB-Ser16 normalized to PLB. (E) Quantification of pPLB-Thr17 normalized to PLB. Data reported as fold change relative to Sham-Normo. * P <0.05 vs. respective sham; # <0.05 vs. AS-N, n = 6 each group.

Fig 5. Abundance of saturated and unsaturated fatty acids of cardiac lipid pools is not altered with diet in hypertrophied hearts. The abundance of saturated and unsaturated fatty acids was determined in lipid extracts from cardiac tissue in Sham and AS hearts fed normolipidic (Normo) or high-unsaturated fat diet (HUFA). Lipid extracts were separated into: (A) saturated cytosolic free fatty acids (FFAs); (B) unsaturated FFAs; (C) saturated fatty acids from diacylglycerol (DAG); (D) unsaturated fatty acids from DAG; (E) saturated fatty acids from triacylglycerol (TAG); (F) unsaturated fatty acids from DAG. All saturated fatty acids and unsaturated fatty acids, as determined by GC-MS analysis, were summed and the percentage of total fatty acids was calculated. Data are reported as mean ± SEM for each group. # p<0.05 vs. Sham-HUFA, n = 5 each group.

Fig 6. Decreased abundance of oleic and linoleic acid in hypertrophied hearts is not restored by diet. The relative abundance of individual fatty acids present in lipid extracts from cardiac tissue in Sham and AS hearts fed normolipidic (Normo, Sham-N and AS-N) or high unsaturated fat diet (HUFA, Sham-H and AS-H). Lipid extracts were separated into: (A) total cytosolic free fatty acids (FFAs); (B) diacylglycerol (DAG); and (C) triacylglycerol (TAG). Data is reported as relative abundance as determined by GC-MS analysis. * p<0.05 vs. Sham-N; # p<0.05 vs. Sham-H, (n = 5 each group).