Coronary Atherosclerosis Is Associated With Macrophage Polarization in Epicardial Adipose Tissue

Study Questions:

What is the link between macrophage polarization in epicardial adipose tissue and atherosclerosis in patients with coronary artery disease (CAD)?

Methods:

Samples were obtained from epicardial and subcutaneous adipose tissue during elective cardiac surgery (CAD, n = 38; non-CAD, n = 40). Infiltration of M1/M2 macrophages was investigated by immunohistochemical staining with antibodies against CD11c and CD206, respectively. Expression of pro- and anti-inflammatory adipocytokines in adipose tissue was evaluated by real-time quantitative polymerase chain reaction. The investigators compared the valuables between groups by two-way analysis of variance, and correlations were assessed with Spearman’s rank correlation for non-normally distributed data.

Results:

Infiltration of macrophages and expression of pro- and anti-inflammatory cytokines were enhanced in epicardial fat of patients with CAD compared with that in non-CAD patients (p < 0.05). The ratio of M1/M2 macrophages was positively correlated with the severity of CAD (r = 0.312, p = 0.039). The expression of pro-inflammatory cytokines was positively correlated, and the expression of anti-inflammatory cytokines was negatively correlated with the ratio of M1/M2 macrophages in epicardial adipose tissue of CAD patients. By contrast, there was no significant difference in macrophage infiltration and cytokine expression in subcutaneous adipose tissue between the CAD and non-CAD groups.

Conclusions:

The authors concluded that the ratio of M1/M2 macrophages in epicardial adipose tissue of CAD patients is changed compared with that in non-CAD patients.

Perspective:

This study suggests that infiltration of macrophages and expression of pro- and anti-inflammatory cytokines were enhanced in the epicardial fat of patients with CAD, compared with those in non-CAD patients. Furthermore, the expression of pro-inflammatory cytokines was positively correlated and the expression of anti-inflammatory cytokines was negatively correlated with the ratio of M1/M2 macrophages in epicardial adipose tissue in the CAD group. Overall, the results suggest that macrophage polarization might influence atherogenesis in human coronary arteries.

Keywords: Coronary Artery Disease, Atherosclerosis, Macrophages, Biomarkers, Cytokines, Subcutaneous Fat


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