Poster Topical Area: Energy and Macronutrient Metabolism
Location: Hall D
Poster Board Number: 531
Objective: Dietary fat type influences epicardial adipose tissue (EAT) fatty acid (FA) composition in Ossabaw pigs. Saturated FAs (SFA) can increase inflammation and some polyunsaturated FAs (PUFA) can decrease inflammation via direct/indirect modification of gene expression. Here we examine the associations of select EAT SFAs and PUFAs with gene expression in the Ossabaw pig.
Methods: Thirty Ossabaw pigs were randomized into four groups and fed isocaloric amounts of a Heart-Healthy diet (high in unsaturated fat, whole grain, fruits/vegetables) or Western diet (high in saturated fat, cholesterol, refined grain), ± atorvastatin, for 6 months. EAT adjacent to the left anterior descending coronary artery was collected. Gene expression was determined by RNA sequencing and FA composition by gas chromatography. Pigs from all groups were pooled and Spearman's correlation coefficients were calculated between selected EAT FAs (mol%) and EAT gene expression (rpkm).
The following associations were significant (p <.0003). SFAs (total SFA, capric, lauric, palmitic and stearic acids) had moderate (r =0.2-.49) positive associations with IRF7 and IFIT1. SFAs also had moderate (r =0.2-.49) positive associations with PTGS2, but associations were weak (r <0.2) for capric and lauric acids. Total n-6 PUFA, linoleic acid and n-3 PUFAs (total n-3 PUFA, α-linolenic, eicosapentaenoic, docosapentaenoic and docosahexaenoic acids [DHA]) had strong positive (r > 0.50) associations with FFAR4 and PPARG. Weak (r <0.20) to moderate (r =0.20-.49) positive associations emerged between ALOX5 and all PUFAs. DHA was negatively associated with IL-1β (r=0.35), and capric and lauric acids were negatively and weakly associated with IL-6 (r<0.20). No significant associations were found between any FAs and TLR2, TLR4, MCP1 and IRF3.
Conclusion: EAT SFAs were positively associated with expression of two interferon signaling genes (IRF7 and IFIT1) and PTGS2, whereas PUFAs were positively associated with expression of two anti-inflammatory genes (FFAR4 and PPARG). Associations between proportions of EAT SFAs and PUFAs with the expression of genes related to inflammation provide a link between dietary type fat and EAT inflammation. Changes in dietary fat type represents a potential nutritional strategy to reduce EAT inflammation.
Tufts University Friedman School of Nutrition Science and Policy