Short-term effect of intravitreal ranibizumab on intraocular concentrations of vascular endothelial growth factor-A and pigment epithelium-derived factor in neovascular glaucoma.

BACKGROUND

This study aims to evaluate concentrations of pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor (VEGF)-A in aqueous of patients with neovascular glaucoma prior to, and shortly after, an intravitreal ranibizumab injection.

DESIGN

Interventional comparative study.

PARTICIPANTS

The study included patients undergoing an intravitreal ranibizumab injection about one week before anti-glaucomatous surgery (study group) or who underwent routine cataract surgery (control group).

METHODS

Aqueous and blood samples were collected at the occasions of intravitreal injections, anti-glaucomatous surgery or cataract surgery. They were analysed by enzyme-linked immunosorbent assay.

MAIN OUTCOME MEASURES

Concentrations of PEDF and VEGF-A in aqueous.

RESULTS

At baseline, concentrations VEGF-A (3698 ± 2105 pg/mL vs. 233 ± 98 pg/mL) and PEDF (18.9 ± 11.9 ug/mL vs. 2.2 ± 0.6 ug/mL) were higher (P < 0.001) in the study group (n = 20 patients) than control group (n = 20 patients). The VEGF-A/PEDF concentration ratio was higher in the study group (396 ± 554 vs. 110 ± 49; P = 0.02). One week after the ranibizumab injection, iris neovascularization had completely regressed in 17 (85%) eyes, and VEGF-A concentration decreased significantly (P < 0.001) to 184 ± 130 pg/mL. The PEDF concentration remained unchanged (19 ± 12 ug/mL). The VEGF-A/PEDF concentration ratio decreased to 13.2 ± 13.6. Plasma concentrations of VEGF-A and PEDF did not differ significantly between both groups (P = 0.65 and P = 0.15, respectively) nor were they significantly correlated with the aqueous concentrations (all P > 0.15).

CONCLUSIONS

Aqueous concentrations of VEGF-A and PEDF were significantly elevated in eyes with neovascular glaucoma. Within one week after intravitreal injection of ranibizumab, VEGF-A concentration decreased to subnormal levels, while the PEDF concentration remained unchanged and the VEGF-A/PEDF ratio decreased.