Assessment of selected adhesion molecule and proinflammatory cytokine levels in the vitreous body of patients with type 2 diabetes - role of the inflammatory-immune process in the pathogenesis of proliferative diabetic retinopathy

The aim of the study is to demonstrate the participation of the inflammatory-immune process in the pathogenesis of proliferative diabetic retinopathy (PDR). Twenty four women and 22 men with type 2 diabetes (mean age 63.97 +/- 9.00 years, mean duration of diabetes 12.56 +/- 6.87 years) were enrolled in the study. Serum concentrations of soluble forms of ICAM-1, VCAM-1 as well as IL-6 and TNF-alpha were evaluated in all study subjects. In 19 patients, simultaneous assessment of selected parameter levels in both serum and vitreous samples was performed. Vitrectomy was performed due to intravitreal hemorrhage, accompanied in some patients by traction retinal detachment. The control group consisted of 15 patients having undergone vitrectomy for reasons other than PDR. Tests were performed using the ELISA method. Serum and intraocular concentrations of sICAM-1, sVCAM-1, IL-6, TNF-alpha were considerably higher in study subjects with PDR than in controls. Simultaneously, a positive correlation was found between intraocular sVCAM-1 (r=0.590, p=0.007), TNF-alpha (r=0.822, p < 0.001) concentrations and HbA(1)c levels. The above-mentioned dependence was not shown for sICAM-1 and IL-6 vitreous concentration. Local vitreous VCAM-1 level increase was also dependent on vitreous TNF-alpha concentration growth (r=0.470, p=0.043). No significant correlation was found between serum and vitreous levels of the selected parameters in the group of 19 patients with PDR. Increase in sICAM-1 and sVCAM-1 levels, as well as their correlation with high vitreous IL-6 and TNF-alpha concentrations in patients with PDR, seem to confirm the inflammatory-immune nature of this process. In diabetes, inadequate metabolic control remains an important risk factor in the development of PDR.