Interleukin 6 may be related to indoleamine 2,3-dioxygense function in M2 macrophages treated with small dense LDL particles

Macrophages are known as important immune cells involved in the improvement of atherosclerosis plaques. The M2 macrophages are beneficial because scavenging the non-functional components in vessel sub-endothelial space. In this study, we investigated the effects of small dense LDL (sdLDL) on the changes of indoleamine 2,3-dioxygense (IDO) and interleukin (IL6) in the differentiated M2 macrophages. The patients were selected from who underwent coronary artery angiography. The monocytes were isolated from the whole blood samples of healthy (< 5% stenosis) and patient (> 70% stenosis; SVD, 2VD and 3VD) subjects and, were differentiated into M2 macrophages. The IDO gene expression, activity and IL6 values were measured by RT-qPCR, colorimetry and ELISA techniques, respectively. In contrast with healthy group, the IDO gene expression and activity were significantly reduced in SVD and 2VD groups (P < 0.05). Furthermore, they were conversely associated to secretion of IL6. In conclusion, the data suggested that inflammatory responses in M2 macrophages differentiated from monocytes of patients after treatment of sdLDL may be related to the reduced IDO function.