To investigate the levels of angiopoietin-2 (Ang2) and vascular endothelial growth factor (VEGF) in the vitreous fluids of patients with proliferative diabetic retinopathy (PDR) and to ascertain their involvement, if any, in angiogenesis of PDR.

Retrospective case-control study.

Forty-one eyes of 41 patients with proliferative diabetic retinopathy and 18 eyes of 18 patients with nondiabetic ocular diseases (control group). Nondiabetic control eyes included 11 with idiopathic macular hole and 7 with idiopathic epiretinal membrane. Vitreous fluid samples were obtained at vitrectomy, and the levels of Ang2 and VEGF were measured by enzyme-linked immunosorbent assay.

Vitreous level (mean ± SD) of Ang2 was significantly higher in patients with PDR (1,753 ± 3,213 pg/ml) than in control patients (112 ± 113 pg/ml) (P < .0001). The vitreous concentration of VEGF was also significantly higher in patients with PDR (812 ± 1,108 pg/ml) than in control patients (1.7 ± 4.4 pg/ml) (P < .0001). Both Ang2 and VEGF levels in eyes with active PDR were significantly higher than in those with inactive PDR. The vitreous concentration of Ang2 correlated significantly with that of VEGF in eyes with proliferative diabetic retinopathy ([correlation coefficient] ρ = 0.497, P = .001).

These data demonstrate an increase of Ang2 in the vitreous fluid of patients with PDR and suggest an association of Ang2 and VEGF with angiogenic activity in PDR.