Interleukin-18(IL-18) and Atherosclerosis

Atherosclerosis is a dynamic and progressive disease arising from the combination of endothelial dysfunction and inflammation. So, inflammatory mediators are important causative and progressive factors in atherosclerosis. Interleukin-18 (IL-18) is a pleiotropic cytokine which may have a key role in atherosclerosis, because the results of recent studies indicated that IL-18, either directly as a pro-inflammatory factor or indirectly as an interferon inducing factor, has central role in the inflammatory cascade. In present study, we evaluated the relation between blood concentration of IL-18 with atherosclerosis and its severity and also the relation of this cytokine with the other known risk factors of coronary artery disease (CAD).138 patients who underwent diagnostic cardiac catheterization and had the inclusion criteria for this study, were selected. In the beginning, a questionnaire containing personal information and medical history was completed for each of them and blood samples were collected 24 hours before catheterization. We measured blood level of IL-18 and CRP in all samples. The results of these tests and the angiography were entered in the questionnaire and then information was analyzed using regression analyzing, K2 and statistical T test. P values of <0.05 were considered statistically significant. By using the results of angiography, patients were divided in two groups. 1- Control group or normal coronary arteries (32 people) 2- Case group (106 people) or patients who were suffering from CAD. In second group, 6 patients (5.6%) had minimal CAD, 44 patients (41.5%) had single-vessel disease (SVD), 27 patients (25.4%) had 2VD and 29 patients (27.5%) had 3VD. In the laboratory tests, the mean IL-18 blood level in patients with CAD was 258.1 pgr/ml but in normal coronary arteries group it was 216.6 pgr/ml. The average blood level of IL-18 in patients who had minimal CAD was 235.5 pgr/ml, in SVD was 247.2 pgr/ml, in 2VD was 263.7 pgr/ml and in patients with 3VD was 274.1 pgr/ml. Also average CRP blood level in normal group was 8.9 mgr/L while in patients with CAD it was 20.4 mgr/L.The results of this study indicated that there was a direct and significant correlation between blood IL-18 level with existence (P<0.001) and severity of CAD(P<0.01) and IL-18 can be an independent predictor risk factor of atherosclerosis