Quantification of vitreous VEGF-A121 and VEGF-A165 using an isoform-specific ELISA in proliferative diabetic retinopathy.

BACKGROUND: To evaluate the utility of specific enzyme-linked immunosorbent assays (ELISAs) for identifying vascular endothelial growth factor (VEGF)-A isoforms in the context of ophthalmic diseases, using proliferative diabetic retinopathy (PDR) as a representative model. METHODS: This was a single-institute, retrospective cohort study of patients with epiretinal membrane (ERM), rhegmatogenous retinal detachment (RRD), or PDR who underwent pars plana vitrectomy at Kagoshima University Hospital between January 2016 and August 2023. We measured vitreous VEGF-A121 and VEGF-A165 concentrations using a VEGF-A isoform-specific ELISA and compared them among the ERM, RRD, and PDR groups. RESULTS: The study included 48 patients (48 eyes): 12 with ERM, 26 with RRD, and 10 with PDR. The concentration of VEGF-A121 was significantly greater in eyes affected by PDR (vs. ERM, P = 2.0 × 10- 4; vs. RRD, P = 2.9 × 10- 5). A similar trend was observed for the concentration of VEGF-A165 (vs. ERM, P = 1.0 × 10- 4; vs. RRD, P = 1.0 × 10-4 ). The levels of VEGF-A121 and VEGF-A165 did not differ significantly between RRD and ERM (P = 0.855 and P = 0.136, respectively). After adjusting for age and sex, the VEGF-A165 levels in eyes with PDR were negatively associated with the patient's eGFR (β = -3.5; P = 0.040) and the HbA1c level (β = -84.6; P = 0.020). CONCLUSION: These findings demonstrate this isoform-specific ELISA enables the measurement of VEGF-A isoforms in the vitreous. Quantification of vitreous VEGF-A isoforms may provide as crucial biomarkers for PDR.