Serum levels of IL-37 and correlation with inflammatory cytokines and clinical outcomes in patients with coronary artery disease

Coronary artery disease (CAD) due to atherosclerosis is one of the important reasons for death worldwide. Recent evidence has suggested the essential role of inflammation in the progression of atherosclerosis. Interleukin (IL)-37 is a critical anti-inflammatory member of the IL-1 family which regulates the inflammatory processes. The aim of this study was to compare the serum levels of IL-37 in patients with CAD compared with the control group and its correlation with oxidative stress, cholesterol homeostasis, and inflammation in patients with CAD. A total of 42 patients with CAD and 42 sex-matched and age- matched controls who underwent coronary angiography were included in this study. The serum levels of IL-37 were evaluated via ELISA. Serum levels of biochemical risk factors were determined by enzymatic methods. Serum levels of IL-37 in the CAD group subjects were significantly lower than in the control group and IL-37 was significantly increased in men with CAD than in women with CAD. IL-37 significantly had an inverse correlation with IL-6, tumor necrosis factor-alpha, IL-32, high-sensitivity C reactive protein, oxidized low-density lipoprotein, and malondialdehyde. Also, IL-37 had a significantly positive correlation with ferric-reducing antioxidant power (FRAP) assay. In addition, IL-37 has positively correlated with ATP-binding cassette transporter A1 and G1 gene expression in peripheral blood mononuclear cells and serum levels of the FRAP. A receiver operating characteristic test displayed that IL-37 level ratios were a relatively significant CAD predictor. Our results indicated that decreased serum levels of IL-37 in patients with CAD and its relationship with inflammatory cytokines and reverse cholesterol transport genes are more likely to be associated in the inflammatory process with disease pathology.