Abstract 13921: Macrophage Polarization in Epicardial Adipose Tissue is Correlated with Severity of Human Coronary Artery Disease
Introduction: It has been reported that epicardial fat as local visceral fat depot may serve as a source of inflammatory cytokines in coronary atherosclerotic lesions. It was also reported that macrophage accumulation enhances the chronic inflammation in adipose tissue. Recently, it was reported that adipose tissue macrophages can exist in different activation states: either pro-inflammatory classically activated state (M1), or anti-inflammatory alternatively activated state (M2). However, the macrophage phenotypic changes in human epicardial fat are unknown. We assessed the hypothesis that macrophage polarization in epicardial fat is associated with the atherogenesis in human coronary arteries.
Methods: Pare samples were obtained from epicardial adipose tissue (EAT) and subcutaneous adipose tissues (SCAT) during coronary artery bypass grafting surgery (CAD group, n=38) and valve replacement surgery (non-CAD group, n=40). Infiltration of M1/M2 macrophages was investigated by immunohistochemistry using antibodies against CD68 (total macrophages), CD11c (M1 macrophages), CD206 (M2 macrophages), respectively. We analyzed the expression of pro- and anti-inflammatory cytokines in adipose tissue by real-time PCR.
Results: The number of infiltrating macrophages and expression of pro- and anti-inflammatory cytokines were increased in EAT of CAD group compared with those in non-CAD group (P<0.05, respectively). The ratio of M1/M2 macrophage was positively correlated with severity of CAD as determined by the Gensini score (r=0.312, P=0.039). Furthermore, the expression of pro-inflammatory cytokines are positively correlated, and anti-inflammatory cytokines are negatively correlated, with the ratio of M1/M2 macrophages in EAT of CAD group. On the other hand, there was no significant difference between the two groups in macrophage infiltration and cytokine expression in SCAT.
Conclusion: The ratio of M1/M2 macrophages ‘shifted’ toward inflammatory state in EAT of CAD patients compared to non-CAD patients. The macrophage polarization in epicardial adipose tissue may influence the atherogenesis in human coronary arteries.
- © 2010 by American Heart Association, Inc.