Intravitreous VEGF-A in eyes with massive vitreous hemorrhage

Although vascular endothelial growth factor (VEGF) is abundant in serum, the intraocular concentration of VEGF in eyes with massive vitreous hemorrhage (VH) is not well-known. The present study was conducted to elucidate the effects of a massive VH on intravitreous VEGF concentration.

Vitreous samples were obtained during vitrectomy: 12 samples from eyes with epiretinal membrane without diabetic retinopathy (DR), and nine samples from massive VH with no DR, such as age-related macular degeneration, rhegmatogenous VH, Terson's syndrome and macro-aneurysm rupture. Twelve samples were obtained from proliferative DR. VEGF was measured with an enzyme-linked immunosorbent assay (ELISA). Samples incubated with or without heparin were also examined for the release of VEGF binding to the vitreous body. The localization of VEGF and type II collagen in the vitreous was evaluated from immunohistochemistry.

The concentration of VEGF was significantly higher in eyes with proliferative DR (821 ± 949 pg/ml) than in non-DR with massive VH (2.75 ± 7.5 pg/ml, P < 0.01, chi-square test) or non-DR with no VH (less than detectable level, P < 0.01, chi-square test) There was no statistically significant difference between eyes with massive VH and non-diabetic eyes without VH. Treatment with heparin did not significantly affect the concentration of vitreous VEGF. VEGF was localized mainly in the clot from the results of an immunohistochemical analysis.

Even with a massive VH, diffusible VEGF does not increase significantly in the liquid phase and is principally present in a clot. VH alone should not be an indication for vitrectomy from the point of view of VEGF-related pathology.