Different expression of vascular endothelial growth factor and pigment epithelium-derived factor between diabetic and non-diabetic epiretinal membranes

Purpose: To determine whether there is a difference in protein levels of expression of vascular endothelial growth factor (VEGF), pigment epithelium-derived factor (PEDF), platelet-derived growth factor (PDGF) and transforming growth factor β₁ (TGF-β₁) between diabetic and non-diabetic epiretinal membranes (ERMs). Methods: ERMs and vitreous were surgically removed from the eyes of 8 patients with proliferative diabetic retinopathy and from 6 patients with proliferative vitreoretinopathy. Concentrations of VEGF, PEDF, PDGF and TGF-β₁ were investigated by an enzyme-linked immunosorbent assay. Results: The concentrations of VEGF were higher in ERMs from patients with diabetes (9.2 ± 8.0 pg/μg protein) compared to those without diabetes (1.2 ± 3.0 pg/μg protein; p = 0.026), while the concentrations of PEDF were higher in ERMs from patients without diabetes (7.5 ± 1.5 ng/μg protein) compared to those with diabetes (3.5 ± 1.5 ng/μg protein; p = 0.002). In addition, the VEGF-to-PEDF ratio was higher in diabetic ERMs (2.80 ± 1.83) than in non-diabetic ones (0.17 ± 0.09; p = 0.019). However, the concentrations of PDGF and TGF-β₁ in membranes were not different between patients with diabetes and those without diabetes. Conclusion: This study found the difference in protein levels of expression of VEGF and PEDF between diabetic and non-diabetic ERMs. These results suggest that a disturbance in the balance between angiogenic and anti-angiogenic factors may play an important role in angiogenesis in diabetic ERMs.