Pigment Epithelial-Derived Factor Peptide Facilitates the Regeneration of a Functional Limbus in Rabbit Partial Limbal Deficiency

To investigate the potential of a pigment epithelial-derived factor (PEDF) peptide 44-mer to promote limbal regeneration in a rabbit partial limbal deficiency model. Limbal excision (180°) was created surgically, and topical application of 44-mer-containing ointment once a day for 2 weeks was started immediately after injury. Limbal barrier function was inspected at 2 and 6 months after treatment. Corneal neovascularization was observed under slit-lamp microscope. The presence of goblet cells on the corneal surface was examined using impression cytology. The resulting repair tissue was assessed by immunohistochemical staining with antibodies for putative limbal stem cell (LSC) markers ΔNp63α and ABCG2. Cells harvested from the regenerated tissue were analyzed for colony-forming capacity and expression of LSC markers by immunostaining assay and quantitative real-time PCR (qPCR). Eyes treated with the 44-mer blocked vascularization and goblet cell migration onto the corneal surface. By means of immunohistochemical staining and cell isolation in the repair tissue, we showed that LSCs were widely distributed at the regenerated tissue after 44-mer treatment. The repaired limbus contributed robustly to corneal wound healing as effectively as undamaged limbus. We demonstrated that 44-mer regenerates a functional limbus-like structure on limbal excision wounds. Our finding suggests that the PEDF peptide derivative may be an innovative strategy for tissue engineering and repair therapy in partial LSC deficiency diseases.