Survival of rabbit limbal stem cell allografts after administration of cyclosporin

Objectives, To evaluate the efficacy of systemic or topical administration of cyclosporin A (CsA) after limbal transplantation of stem cell allografts in rabbits. Methods. Thirty-six rabbits underwent corneal epithelial debridement and limbal ablation to induce ocular surface disease and were then treated by limbal allograft transplantation. Animals received either systemic CsA (10 mg/kg per day, intramuscularly), 1% CsA eyedrops, drops, or vehicle eyedrops immediately after transplantation and 28 days thereafter. Concentration of CsA in plasma and aqueous humor was determined by fluorescence polarization immunoassay after 4 weeks of therapy. Graft survival was inspected clinically. Results. Both systemic and topical administration of CsA resulted in a significant prolongation of graft survival. In addition, one of seven of the limbal allografts in either group of systemic and topical CsA survived >60 days on cessation of CsA. There was no significant difference in mean survival time between systemic and topical application, although plasma levels of CsA were significantly higher after systemic administration. However, a significant higher aqueous concentration was found in topical treatment. Conclusions. Limbal allografts were stable in maintaining the reconstructed ocular surface under attentive postoperative immunosuppression. Topically administered CsA was as effective as systemic use.