Epicardial adipose tissue (EAT) expresses lower levels of adiponectin in patients with CAD and higher levels of inflammatory mediators such as IL-6 and leptin than subcutaneous adipose tissue. This showed one important role of EAT in coronary artery disease. However, the relationship of EAT adiponectin and IL-6 levels to the extension of coronary artery disease has not hitherto been determined. We sought to determine whether the levels of adiponectin and interleukin-6 (IL-6) mRNA in epicardial adipose tissue are associated with the extension of coronary artery disease (CAD).
Methods: Angiographic and hormones expression were evaluated from epicardial and subcutaneous adipose tissue. 92 patients (58 CAD, 34 non-CAD) who underwent cardiac surgery. Adiponectin and IL-6 mRNA levels were measured by real time RT-PCR in epicardial and subcutaneous adipose tissue (SAT) following angiographic evaluation of their coronary arteries.
Results: We found that epicardial adipose tissue of CAD expressed lower levels of adiponectin mRNA and higher levels of IL-6 mRNA than that of non-CAD patients. As the number of injured arteries rose, adiponectin mRNA levels decreased (r=-0.402, p<0.001) and IL-6 mRNA increased (r=0.514, p<0.001) in epicardial adipose tissue.
Conclusions: The extension of CAD is significantly associated with the expression of adiponectin and IL-6 mRNA in EAT. These findings suggest that low adiponectin and high IL-6 expression by EAT may contribute to CAD extension.