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This abstract is assigned to session SBO-BOG Free papers: Glaucome/Glaucoma

Title

Inhibition of Vascular Endothelial Growth Factor Reduces Scar Formation after Glaucoma Filtration Surgery

Purpose	In 30-50% of cases, glaucoma filtration surgery fails due to excessive post-operative scarring. In this study, we investigated whether glaucoma and filtration surgery are associated with increased levels of vascular endothelial growth factor (VEGF) and whether the humanized monoclonal VEGF-antibody bevacizumab (AvastinTM, Genentech) can reduce post-operative scar formation and improve surgical outcome.
Methods	VEGF levels in aqueous humor samples were measured by ELISA. Expression of VEGF-receptors Flt-1 and KDR was analyzed in cultured Tenon fibroblasts by real-time RT-PCR and Western blot. The effect of VEGF and bevacizumab on Tenon fibroblasts in vitro was determined using a proliferation assay. The effect of the antibody in vivo was investigated in a rabbit trabeculectomy model by measuring the intra-ocular pressure (IOP) and the bleb area and by immunohistological analysis of vascularity, inflammation and fibrosis.
Results	VEGF was significantly increased in the aqueous humor of glaucoma patients as well as in operated rabbits. Both VEGF-receptors were expressed on Tenon fibroblasts. The proliferation of Tenon fibroblasts in vitro was significantly stimulated by VEGF-delivery and inhibited by bevacizumab-administration. The antibody also significantly reduced vascularity and collagen deposition and improved glaucoma surgery outcome.
Conclusion	VEGF is up-regulated in aqueous humor of glaucoma patients and operated rabbits and stimulates in vitro fibroblast proliferation, suggesting that it plays a role in the scarring process after filtration surgery. Bevacizumab reduces in vitro fibroblast proliferation and improves in vivo surgical outcome.

Author 1

Last name	VAN BERGEN
Initials	TVB
Department	KUL
City	Leuven

Author 2

Last name	VAN DE VEIRE
Initials	SVDV
Department	KUL
City	Leuven

Author 3

Last name	MOONS
Initials	LM
Department	KUL
City	Leuven

Author 4

Last name	STALMANS
Initials	IS
Department	KUL
City	Leuven