Serum interleukin-18 and carotid intima-media thickness in patients with type 2 diabetes mellitus

Background Interleukin-18 (IL-18), known as a member of IL-1 family cytokines, is found to be elevated as a part of the chronic low-grade inflammatory process in obesity, metabolic syndrome, and type 2 diabetes (T2D). Patients with carotid intima-media thickness (CIMT) exhibited a higher level of IL-18 in the serum. Objective To study the relation between serum IL-18 and CIMT in patients with type 2 diabetes mellitus (T2DM). Patients and methods A total of 60 patients diagnosed as having T2D and 30 age-matched and sex-matched patients as a control group were recruited in this study. Diabetic patients were divided into two groups according to the presence or absence of diabetic nephropathy. Clinical examination and laboratory investigations including serum IL-18 (by ELISA) and CIMT of both common carotid arteries were carried out. Results Mean serum IL-18 level was significantly increased in patients with T2DM when compared with the control group. There was a significant increase in the mean serum IL-18 in patients with diabetic nephropathy compared with those patients without nephropathy. Moreover, there was a significant positive correlation between serum IL-18 and CIMT, glycated hemoglobin, serum lipids, creatinine, urea, and urinary protein in patients with T2DM (group I) (P<0.001). Conclusion Serum IL-18 level and CIMT were higher in T2DM than that in controls and in diabetic patients with nephropathy compared with those without nephropathy. Higher serum IL-18 levels correlated with larger CIMT, suggesting a role of IL-18 in atherosclerosis.