The role of pericardial adipose tissue in the heart of obese minipigs

Background: Pericardial adipose tissue (PAT) volume is highly associated with the presence and severity of cardiometabolic diseases, but the underlying mechanism is unknown. We previously demonstrated that a high-fat diet (HFD) induced metabolic dysregulation, cardiac fibrosis and accumulation of more PAT in minipigs. This study used our obese minipig model to investigate the characteristics of PAT and omental visceral fat (VAT) induced by a HFD, and the potential link between PAT and HFD-related myocardial fibrosis. Materials and methods: Five-month-old Lee-Sung minipigs were made obese by feeding a HFD for 6 months. Results: The HFD induced dyslipidemia, cardiac fibrosis and more fat accumulation in the visceral and pericardial depots. The HFD changes the fatty acid composition in the adipose tissue by decreasing the portion of linoleic acid in the VAT and PAT. No arachidonic acid was detected in the VAT and PAT of control pigs, whereas it existed in the same tissues of obese pigs fed the HFD. Compared with the control pigs, elevated levels of malondialdehyde and TNFα were exhibited in the plasma and PAT of obese pigs. HFD induced greater size of adipocytes in VAT and PAT. Higher levels of GH, leptin, OPG, PDGF, resistin, SAA and TGFβ were observed in obese pig PAT compared to VAT. Conclusion: This study demonstrated the similarities and dissimilarities between PAT and VAT under HFD stimulus. In addition, this study suggested that alteration in PAT contributed to the myocardial damage.