IN-VIVO INHIBITION OF LENS REGROWTH BY FIBROBLAST GROWTH-FACTOR 2-SAPORIN

Purpose. To investigate the ability of fibroblast growth factor (FGF) 2-saporin to prevent lens regrowth in the rabbit. Methods. Chemically conjugated and genetically fused FGM-saporin (made in Escherichia coli ) were used. Extracapsular extraction of the lens was performed on the rabbit, and the cytstoxin either was injected directly into the capsu le bag or was administered by FGF2-saporin-coated, heparin surface-mod ified (HSM) polymethylmethacrylate intraocular lenses. The potential o f the conjugate was checked by slit lamp evaluation of capsular opacif ication and by measuring crystallin synthesis. Toxin diffusion and sit es of toxin binding were assessed by immunohistochemistry. Possible to xicity was determined by histologic analysis of ocular tissues. Result s. FGF2-saporin effectively inhibited lens regrowth when it was inject ed directly into the capsular bag. However, high concentration of the toxin induced transient corneal edema and loss of pigment in the iris, Intraocular lenses coated with FGF2-saporin reduced lens regrowth and crystallin synthesis without any detectable clinical side effect. Aft er implantation, FGF2-saporin was shown to have bound to the capsules and, to a lesser extent, to the iris; no histologic damage was found o n ocular tissues as a result of implantation of drug-loaded HSM intrao cular lenses. Conclusions. Chemically conjugated (FGF(2)-SAP) and gene tically fused FGF2-saporin (rFGF(2)-SAP) bound to HSM intraocular lens es can prevent lens regrowth in the rabbit.