Aqueous concentrations of VEGF and soluble VEGF receptor-1 in diabetic retinopathy patients

BACKGROUND: The aim of this study was to simultaneously measure the concentrations of vascular endothelial growth factor (VEGF) and soluble VEGF receptor-1 (sVEGFR-1, also known as sFlt-1) in the aqueous humor of patients with non-proliferative diabetic retinopathy (NPDR) and to investigate whether aqueous levels of vascular endothelial growth factor (VEGF) and VEGFR-1 are related to diabetic macular edema. MATERIALS AND METHODS: Aqueous humor was collected from 27 diabetic patients and 33 age- and sex-matched normoglycemic controls and analyzed for pro-angiogenic VEGF and angiogenic inhibitor VEGFR-1 by enzyme-linked immunosorbent assay (ELISA). The mean foveal thickness was measured by optical coherence tomography (OCT). RESULTS: There was no significant difference in the aqueous levels of VEGF in patients with NPDR compared with control subjects (P > 0.05), while the NPDR patients had significantly lower sVEGFR-1 in their aqueous humor. Furthermore, a significant (P < 0.01) positive correlation was observed between VEGF/sVEGFR-1 concentration and the mean foveal thickness measured on OCT. CONCLUSION: The results suggest that decreased chelating effect of sVEGFR-1 may be the preliminary event allowing VEGF to activate the proangiogenic endothelial cell state and to induce permeability. The imbalance between angiogenic agent (VEGF) and the antiangiogenic factors (sFlt-1), which is disturbed in the diabetic state, may determine the fate of diabetic macular edema.