Greater expression of inflammatory cytokines, adrenomedullin, and natriuretic peptide receptor-C in epicardial adipose tissue in coronary artery disease

Growing evidence suggests that the epicardial adipose tissue may have local interactions with coronary arteries. In addition, vasoactive peptides such as adrenomedullin and natriuretic peptide has an interaction with adipose tissue. In this study, we investigated the relationship between adipokines, adipocytokines, and vasoactive peptides expressed in epicardial adipose tissue and subcutaneous adipose tissue in patients with and without coronary artery disease (CAD). We studied 20 patients with CAD and 14 patients without CAD. We obtained blood samples and epicardial and subcutaneous adipose tissue at open-heart surgery. We measured serum cytokine levels and used real-time polymerase chain reaction (PCR) to measure mRNA levels of various molecules in epicardial and subcutaneous tissue and investigated the relation between mRNA levels and clinical parameters. The mRNA levels of IL-6, IL-1beta, MCP-1, and TNF-alpha were significantly higher in epicardial adipose tissue than in subcutaneous adipose tissue. Interestingly, the mRNA levels of IL-6, IL-1beta, MCP-1, natriuretic peptide receptor-C (NPR-C), adrenomedullin, and leptin in epicardial adipose tissue were higher in patients with CAD than those without CAD. In contrast, mRNA levels of adiponectin, PPAR-gamma, and NPR-A were similar in the two groups. In subcutaneous tissue, mRNA expressions of IL-6, IL-1beta, MCP-1, NPR-C, adrenomedullin, and leptin were modestly higher in patients with CAD than in those without CAD. There were no differences in plasma cytokine levels between the two groups. The mRNA levels of inflammatory cytokines, adipokines, neurohumoral factors and their receptors appear to be increased in epicardial adipose tissue independent of plasma levels of these molecules. Further studies are necessary to elucidate the pathophysiological role of these molecules in CAD. ► The mRNA level of IL-6, IL-β, MCP-1 and TNF-α was greater in epicardial than subcutaneous fat tissue. ► The mRNA level of cytokine, NPR-C and adrenomedullin in epicardial fat was higher in CAD than nonCAD. ► Whereas there were no difference in the mRNA level of adiponectin, leptin, PPAR-γ or NPR-A. ► In subcutaneous tissue, these differences were modest compared with epicardial fat tissue. ► There were no differences in plasma IL-6, TNF-α, or IL-β between CAD and nonCAD.