Poster Topical Area: Energy and Macronutrient Metabolism
Location: Hall D
Poster Board Number: 530
Objective: Epicardial adipose tissue (EAT), a visceral fat depot between the heart and pericardium, is thought to promote the development of coronary artery disease (CAD). Little is known about the influence of dietary fat and statin therapy on EAT fatty acid (FA) composition. Our objective was to examine EAT FAs in Ossabaw pigs fed a Heart-Healthy diet (HHD) or Western diet (WD), ± atorvastatin (S).
Methods: Thirty Ossabaw pigs were randomized into four groups, HHD, HHD+S, WD, WD+S. and fed the respective isocaloric diets, ± atorvastatin, for 6 months. Diets were matched for macronutrient composition but differed in type of dietary fat (unsaturated vs saturated) and carbohydrate (whole vs refined). Pigs fed the HHD were supplemented with fish oil (Epanova 1g, 550mg EPA [eicosapentaenoic acid] + 200mg DHA [docosahexaenoic acid]) 3x per week. EAT adjacent to the left anterior descending coronary artery was collected and FA composition determined by gas chromatography. Desaturase enzyme activities were estimated using FA ratios: stearoyl-CoA-desaturase (SCD1; 161n-7/16:0), SCD2 (18:1n-9/18:0), delta-6-desaturase (D6D; 20:3n-6/18:2n-6) and delta-5-desaturase (D5D; 20:4n-6/20:3n-6). Results were analyzed by a two-way ANOVA.
Results: There was no significant effect of atorvastatin on EAT FA composition. Relative to the HHD, the WD fed pigs had higher proportions of total SFA and trans FAs, including palmitic (16:0), stearic (18:0), vaccenic (18:1n-7t) and conjugated linoleic (18:2 CLA) acids (all p <0.01). There were no significant differences in total MUFA but pigs fed the HHD had higher proportions of oleic acid (18:1n-9) (p <0.01). Pigs fed the HHD also had higher proportions of total n-6 PUFA and n-3 PUFA, including linoleic (18:2n-6), α-linolenic (18:3n-3), EPA (20:5n-3) and DPA (docosapentaenoic [22:5n-3]) acids (all p <0.01). Estimated activities for SCD1 and D6D were higher, and SCD2 was lower in pigs fed the HHD compared to the WD. DHA content and D5D activity were similar between diet groups.
Conclusion: These data document, for the first time, that EAT FA composition is influenced by dietary fat type. Given the potential effect of FAs and FA-derived lipid mediators on inflammation, the modulation of EAT by dietary fat could influence the association between EAT and CAD.
Tufts University Friedman School of Nutrition Science and Policy