Assessment of tear inflammatory cytokines concentration in patients with diabetes with varying severity of involvement.

Diabetic retinopathy (DR), as one of the most important causes of blindness in Western societies, is a common micro-vasculopathy associated with diabetes. There is growing evidence of the role of inflammation in its development. This study was designed to measure cytokines in patients with diabetes with different stages of retinopathy .In this study, tear concentrations of three types of cytokines with different angiogenic properties including IL-1RA, IL-8, and TNF-α were measured in patients with diabetes without retinopathy, with non-proliferative retinopathy, with proliferative retinopathy, and in a healthy control group. The results showed that concentrations of TNF-α and IL-8 were higher in the tear sample of diabetics than in the control group and the concentrations of these cytokines were higher in patients with more advanced stages of diabetes, while the tear level of IL-1RA was significantly lower in diabetics. Based on these findings, it can be concluded that diabetes and its progression of severity affects the tear levels of IL-1RA, IL-8, and TNF-α inflammatory cytokines.