Antiangiogenic isoforms of vascular endothelial growth factor predominate in subretinal fluid of patients with rhegmatogenous retinal detachment and proliferative vitreoretinopathy.

BACKGROUND: In proliferative vitreoretinopathy (PVR), a nonangiogenic eye disease that is characterized by the formation of mainly avascular membranes, vascular endothelial growth factor (VEGF) levels are found to be upregulated. Recently, it was discovered that VEGF is alternatively spliced to form the angiogenic (VEGF xxx) and antiangiogenic (VEGF xxx b) family of isoforms. Previous studies on expression of VEGF in PVR samples have not distinguished between the two families of isoforms.
METHODS: We measured total VEGF and VEGF xxx b levels in subretinal fluid of patients with PVR (n = 10) and in patients with uncomplicated rhegmatogenous retinal detachment (n = 27) using enzyme-linked immunosorbent assay.
RESULTS: : We found total VEGF levels to be 2- to 3-fold elevated in the PVR group as compared with the rhegmatogenous retinal detachment group (P = 0.047). Antiangiogenic VEGF xxx b isoforms predominated (>60% of total VEGF) in the majority of rhegmatogenous retinal detachment and PVR samples investigated, although a wide variability of isoform ratios was observed within both groups.
CONCLUSION: The absence of an increased ratio of VEGF xxx to VEGF xxx b in patients with PVR as compared with patients with uncomplicated rhegmatogenous retinal detachment may explain a lack of blood vessels in PVR membranes. Elevated VEGF levels indicate that this cytokine may play a role in the pathogenesis of PVR that is not related to angiogenesis.