Epicardial adipocyte-derived TNF-α modulates local inflammation in patients with advanced coronary artery disease.

Background Epicardial adipose tissue (EAT) surrounds the epicardium and can mediate harmful effects related to coronary artery disease (CAD). Objective We explored the regional differences between adipose stores surrounding diseased and non-diseased segments of coronary arteries in patients with advanced CAD. Methods We enrolled 32 patients with known CAD who underwent coronary artery bypass graft (CABG) surgery. Inflammatory mediators were measured in EAT biopsies collected from a region of the left anterior descending artery (LAD) with severe stenosis (diseased segment) and without stenosis (non-diseased segment). Results Mean age was 64.3±11.1 years, and mean EAT thickness was 7.4±1.9 mm. Dyslipidemia was the most prevalent comorbidity (81% of the patients). Out of a total of 11 cytokines, resistin (p=0.039), matrix metallopeptidase 9 (MMP-9) (p=0.020), C-C motif chemokine ligand 5 (CCL-5) (p=0.021), and follistatin (p=0.038) were significantly increased in the diseased compared with the non-diseased EAT segments. Indexed tumor necrosis factor-alpha (TNF-α), defined as the diseased to non-diseased cytokine levels ratio, was significantly correlated with increased EAT thickness both in the whole cohort (p=0.043) and in a subpopulation of patients with dyslipidemia (p=0.009). Treatment with lipid-lowering agents significantly decreased indexed TNF-α levels (p=0.015). No significant alterations were observed in the circulating levels of these cytokines with respect to CAD-associated comorbidities. Conclusion Perivascular EAT is a source of cytokine secretion in distinct areas surrounding the coronary arteries in patients with advanced CAD. Adipocyte-derived TNF-α is a prominent mediator of local inflammation.