The Measurement of Intraocular Biomarkers in Various Stages of Proliferative Diabetic Retinopathy Using Multiplex xMAP Technology

Purpose. To determine the intraocular levels of growth factors and cytokines in patients with various degrees of severity of proliferative diabetic retinopathy (PDR) using multiplex xMAP technology. Methods. A prospective cohort study of 61 eyes from 56 patients who were divided into 3 groups based on the severity of PDR. Patients in group number 1 are those who presented PDR with no need of repeated surgical intervention; patients in group number 2 had repeated vitreous bleeding; and patients in group number 3 had refractory neovascular glaucoma. The concentrations of proangiogenic, antiangiogenic, inflammatory, and neurotrophic factors were measured in intraocular fluid. The results were also compared with levels of factors measured in 50 eyes from 50 patients prior to senile cataract surgery (control group). Results. Patients with refractory neovascular glaucoma (the highest clinical severity group) had higher levels of interleukin 6 (IL-6) (median1 37.19; median3 384.74; P = .00096), transforming growth factor beta 1 (TGFβ-1) (median1 49.00; median3 414.40; P = .0017), and vascular endothelial growth factor (VEGF) (median1 211.62; median3 352.82; P = .0454) compared with other PDR patients. Conclusions. Results of our study imply that levels of IL-6, TGFβ-1, and VEGF correlate with the severity of PDR.