Cytokine Concentration Correlates with Diabetic Nephropathy

Diabetic nephropathy (DN) is a major microvascular complication of diabetes mellitus, and it is the leading cause of end-stage renal disease and inflammation plays some important roles in the pathogenesis of DN.

Interleukin-19 (IL-19) is a newly discovered cytokine belonging to the Interleukin-10 (IL-10) family. IL-19 cytokines have indispensable functions in many inflammatory processes and also can induce the angiogenic potential of endothelial cells.

Scientists at the Jiangsu University School of Clinical Medicine selected 200 patients with type 2 diabetes mellitus (T2DM) (109 males and 91 females, age 60 ± 10.3 years) from July to December in 2015. According to urinary albumin excretion rate (UAE), the patients were divided into three groups: 102 patients with T2DM with normoalbuminuria, (UAE < 30 mg/24 hours), 72 T2DM patients with microalbuminuria (UAE: 30 to 300 mg/24 hours) and 26 T2DM patients with macroalbuminuria (UAE ≥300 mg/24 hours). There were 50 healthy blood donors enrolled for the control group.

All subjects were assessed for: IL-19, High-sensitivity C-reactive protein (Hs-CRP), Cystatin C, urinary albumin excretion rate (UAE) and glycosylated hemoglobin A1C (HbA1c). IL-19 was determined by the enzyme-linked immunosorbent assay (ELISA) kits. Urinary albumin and Hs-CRP concentrations were assessed using the particle enhanced immuoturbidimetric method. HbA1c was measured by liquid chromatography. Fasting plasma glucose (FPG), total cholesterol (TC), high-density lipoprotein (HDL-C) and LDL cholesterol (LDL-C) were measured by enzymatically.

The team found that the serum IL-19 levels in DN patients were found to be significantly higher compared to controls. IL-19 levels were significantly positively correlated with Hs-CRP, Cystatin C, UAE and HbA1c. In multivariable logistic regression analysis, IL-19 levels (95% CI, 20.1 to 62.9) alone showed a significant positive association with DN even after adjusting for age, gender, hypertension, and blood fat. The HbA1c in the microalbuminuric/macroalbuminuric diabetic group were significantly increased compared to normoalbuminuric and control groups.

The authors concluded that that IL-19 levels was significantly elevated in the patients with diabetic nephropathy and was associated with Hs-CRP, Cystatin C, UAE and HbA1c. The results suggest that IL-19 has an important role in the acceleration of glomerular injury in addition to its inflammatory effect on this pathophysiology, and provide further insights into the understanding of IL-19 as the possible effectiveness of anti-inflammatory therapy for DN treatment and prevention. The study was published on February 15, 2017, in the journal BMC Nephrology.