Suppression of Ischemia-Induced Retinal Neovascularization and, Vascular Endothelial Growth Factor Action by PEDF

Elia J. Duh
Hoseong S. Yang
Keisuke Mori
Patrick Tong
Peter L. Gehlbach
John W. Crabb
Lloyd P. Aiello
Peter A. Campochiaro
Donald J. Zack

Purpose: To determine the effect of recombinant PEDF on retinal neovascularization in the mouse model of oxygen-induced retinopathy and on vascular endothelial growth factor (VEGF)-induced migration and growth of cultured retinal endothelial cells.

Methods: Recombinant PEDF was expressed in HEK293 cells and purified by cation exchange chromatography. C57BL/6 mice were exposed to 75 percent oxygen from postnatal day 7 (P7) to P12 and then returned to room air. Mice received intravitreal injections of PEDF protein in one eye and vehicle in the contralateral eye on P12 and P14. At P17 mice were sacrificed and eyes enucleated for quantitation of retinal neovascularization. The effects of VEGF on migration and proliferation of cultured bovine retinal endothelial cells were examined in the presence or absence of PEDF by cell counting and migration assays.

Results: Two species of PEDF (PEDF A and B), with molecular weights of 46 to 49 kD, were purified to greater than 98 percent homogeneity. PEDF B appeared to comigrate on SDS/PAGE with PEDF from human vitreous samples. The molecular weights of PEDF A and B were determined by mass spectrometry analysis to be 47.2 and 46.4 kD, respectively. Intravitreal administration of either species of PEDF significantly inhibited retinal neovascularization (83 percent for PEDF A and 55 percent for PEDF B). PEDF A and B suppressed VEGF-induced retinal microvascular endothelial cell proliferation by 48.8 percent and 41.4 percent, respectively, and VEGF-induced migration by 86.5 + 16.7 percent and 78.1 + 22.3 percent, respectively.

Conclusions: These data indicate that elevated concentrations of PEDF inhibit VEGF-induced retinal endothelial cell growth and migration as well as retinal neovascularization. PEDF administration may therefore be an effective approach for the treatment of ischemia-induced retinal neovascular disorders.