The role of zonulin in the pathogenesis of diabetic retinopathy

Abstract

Objectives: To evaluate serum levels of zonulin and interleukin 6 (IL-6) in type 2 diabetes mellitus (T2DM) patients complicated by diabetic retinopathy and to investigate the effect of intestinal permeability on diabetic retinopathy (DR) progression. Materials and Methods: Eighty-nine patients with T2DM and 30 healthy controls aged between 18 and 80 years were enrolled. T2DM patients were grouped as without DR (n=30), with non-proliferative DR (n=29), and with proliferative DR (n=30). Serum zonulin and IL-6 levels were measured with the ELISA method. Results: Zonulin levels showed no statistical difference by pairwise comparisons of groups, but IL-6 levels were significantly increased in non-proliferative and proliferative DR groups compared to the HC and without DR groups. Zonulin level was correlated with body mass index and IL-6 level; IL-6 level was correlated with duration of diabetes, fasting blood glucose and HbA1c. While duration of diabetes and serum IL-6 levels had an independent effect on DR development, zonulin had no effect. Conclusions: Serum zonulin levels cannot be used as a biomarker for the progression of the diabetic retinopathy complication.