Transplantation of PEDF-transfected pigment epithelial cells inhibits corneal neovascularization in a rabbit model.

BACKGROUND: The purpose of this study was to investigate the effect of recombinant pigment epithelium-derived factor (rPEDF), secreted by ARPE-19 cells transfected with the human PEDF gene and transplanted subconjunctivally in normal and in rabbits in which corneal neovascularization was elicited by a chemical burn.

METHODS: Twenty grey Chinchilla Bastard rabbits were randomly assigned to four groups; neovascularization was induced in groups A, B, and C by alkali cauterization. Seven days later, group A received no cell implantation, non-transfected ARPE-19 cells were implanted subconjunctivally in group B, and PEDF-transfected ARPE-19 cells were implanted subconjunctivally in groups C and D (non-cauterized). In-vivo rPEDF secretion was analyzed by immunoblotting, and ELISA of extracts of conjunctival tissue samples taken at different time points. Digital photographs acquired on days 7, 14, and 21 after cauterization were evaluated for lead vessel length, vascular invasion area, and overall neovascularization rate.

RESULTS: At days 14 and 21 after cauterization, significant differences were observed between groups A, B, and C in lead vessel length (day 21: 5.91 ± 0.45, 5.11 ± 1.22, 3.79 ± 0.59 mm, repectively), vascular invasion area (day 21: 35.5 ± 8.65, 34.86 ± 4.92, 19.2 ± 5.03 mm(2) respectively), and rate of corneal neovascularization. Compared to controls, neovascularization was reduced by 37.5 % on day 14 and 47 % on day 21. Analysis of conjunctival tissue extracts showed that rPEDF was secreted by the transplanted PEDF-transfected cells.

CONCLUSION: Subconjunctivally transplanted, PEDF-transfected ARPE-19 cells secrete rPEDF, which inhibits the corneal neovascularization elicited by alkali cauterization.