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-alpha), 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 24h urine albumin secretion rate, glycosylated hemoglobin HbA1c level, and C-reactive protein level measured, underwent 24h blood pressure monitoring and had ophthalmologic examination performed. Additionally, all the children had serum TNF-alpha, IL-6 and VEGF level measured using an ELISA test (Quantikine High Sensitivity Human). Statistically significant higher blood serum levels of HbA1c, VEGF, TNF-alpha 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-alpha (R=0.35, p=0.000), CRP level (R=0.23, p=0.006), 24h 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-alpha, IL-6 and the development of the diabetic retinopathy in children with diabetes mellitus type 1.