Macrophage Polarization in the Perivascular Fat Was Associated With Coronary Atherosclerosis

Background Inflammation of the perivascular adipose tissue (PvAT) may be related to atherosclerosis; however, the association of polarized macrophages in the pericoronary PvAT with measurements of atherosclerosis components in humans has not been fully investigated. Methods and Results Coronary arteries were dissected with surrounding PvAT. We evaluated the percentage of arterial obstruction, intima-media thickness, fibrous cap thickness, plaque components, and the number of vasa vasorum. The number of proinflammatory (M1) and anti-inflammatory (M2) macrophages in the periplaque and control PvAT were evaluated using immunohistochemistry. Regression models adjusted for sociodemographic and clinical variables were used. In 319 segments from 82 individuals, we found a correlation of the M1/M2 macrophage density ratio with an increase in arterial obstruction (P=0.02) and lipid content (P=0.01), and a decrease in smooth muscle cells (P=0.02). M1 and the ratio of M1/M2 macrophages were associated with an increased risk of thrombosis (P=0.03). In plaques with thrombosis, M1 macrophages were correlated with a decrease in fibrous cap thickness (P=0.006), an increase in lipid content (P=0.008), and the number of vasa vasorum in the adventitia layer (P=0.001). M2 macrophages were correlated with increased arterial obstruction (P=0.01), calcification (P=0.02), necrosis (P=0.03) only in plaques without thrombosis, and decrease of the number of vasa vasorum in plaques with thrombosis (P=0.003). Conclusions M1 macrophages in the periplaque PvAT were associated with a higher risk of coronary thrombosis and were correlated with histological components of plaque progression and destabilization. M2 macrophages were correlated with plaque size, calcification, necrotic content, and a decrease in the number of vasa vasorum in the adventitia layer.