Increased expression of serum IL-18 and IL-18R in newly diagnosed type 2 diabetes mellitus

Abstract

Type 2 diabetes mellitus (T2DM) is a heterogeneous metabolic disorder in which genetic, sedentary lifestyle, obesity, and environmental factors come together to produce insulin resistance in target tissues, leading to hyperglycemia. Evidence reveals that inflammation may play an essential role in the pathogenesis of T2DM. Interleukin-18 (IL-18), a proinflammatory cytokine, plays a crucial role in the acute and chronic inflammatory process. The association of IL-18 levels with IL-18R expression in T2DM has not been investigated so far. The aim of this study was to compare the peripheral changes in serum IL-18 levels and its receptor (IL18R) expression in newly diagnosed T2DM and healthy controls. A total of 35 newly diagnosed type 2 diabetic cases and 35 non-diabetic controls were enrolled after obtaining informed consent. Venous whole blood was taken under aseptic conditions. Biochemical parameters were estimated in an auto-analyzer. Serum IL-18 levels were calculated using ELISA, whereas IL-18R expression was determined via RT-PCR. GAPDH was used as an internal control. When compared to non-diabetic controls, the serum IL-18 levels were significantly higher in T2DM patients (P=0.010) along with a significant upregulation of IL18R (P=0.0018). Serum IL-18 levels in T2DM and non-diabetic controls were 669.5 (445) and 498.3 (404.9) pg/mL respectively, and IL-18R showed a fold change of 10.33. Both serum IL-18 and its receptor IL-18R is significantly higher in newly diagnosed T2DM patients.