The role of vascular endothelial growth factor, tumor necrosis factor alpha and interleukin-6 in pathogenesis of diabetic retinopathy

The aim of the study was to analyze the relation between early diabetic retinopathy and the pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), vascular endothelial growth factor (VEGF) in children with diabetes mellitus type 1. Two hundred and two children with diabetes mellitus type 1 aged 13.2 ± 3.83 years and 85 healthy controls were analyzed. Patients were divided into two subgroups: children with retinopathy (Group 1, n = 39) and children without retinopathy (Group 2, n = 163). All the children had 24 h urine albumin secretion rate, glycosylated hemoglobin HbA1c level, and C-reactive protein level measured, underwent 24 h blood pressure monitoring and had ophthalmologic examination performed. Additionally, all the children had serum TNF-α, IL-6 and VEGF level measured using an ELISA test (Quantikine High Sensitivity Human). Statistically significant higher blood serum levels of HbA1c, VEGF, TNF-α and IL-6 were found in the Group 1 in comparison with the Group 2. Additionally, the children of the Group 1 showed statistically significant correlation between serum VEGF and serum TNF-α (R = 0.35, p = 0.000), CRP level (R = 0.23, p = 0.006), 24 h albumin urine secretion rate (R = 0.45, p = 0.000) and duration of the disease (R = 0.26, p = 0.002). The results of the current study suggest that there is a relationship between VEGF, TNF-α, IL-6 and the development of the diabetic retinopathy in children with diabetes mellitus type 1.