Corneal endothelial toxicity of air and SF6.

PURPOSE: The authors conducted in vivo assessment of corneal endothelial toxicity of air and SF6 in the feline model. This research was motivated by the increased use of air in anterior segment surgery in human subjects. METHODS: This was a prospective masked study. The eyes of 16 healthy adult cats were randomly assigned for the injection of 0.7 mL air into the anterior chamber of one eye and SF6 in the contralateral eye. Daily examination included slit lamp photographs, pachymetry, and tonometry. Specular microscopy was performed before, 7 days after, and 10 days after injection. The animals were euthanatized, and the corneas were processed for alizarin red-trypan blue staining and for light and electron microscopy. RESULTS: SF6 remained in the anterior chamber significantly longer than air. Both groups showed postinjection inflammation, which on average was maximal at day 2 and more severe with SF6. No difference in IOP was observed between the two groups. Specular microscopy showed significant endothelial cell loss in the SF6 group (mean postinjection cell loss, 132 ± 50 cells/mm(2)) but not in the group injected with air. Alizarin red staining revealed significant regional differences in cell density only in the SF6 group and more pronounced endothelial cell loss in the superior area. CONCLUSIONS: These results indicate that both air and SF6 injected into the anterior chamber of the eye can induce intraocular reaction in the feline model and that SF6 is more toxic than air in terms of endothelial cell loss and anterior chamber inflammation.

Transplantation of a tissue-engineered corneal endothelium reconstructed on a devitalized carrier in the feline model.

PURPOSE: To evaluate the functional outcome of tissue-engineered corneal endothelium reconstructed on a devitalized carrier and transplanted in the living feline model. METHODS: Eighteen healthy adult cats underwent full-thickness corneal transplantation. In 11 animals, the donor cornea was reconstructed from cultured allogeneic feline corneal endothelial cells seeded on the denuded Descemet's membrane of a devitalized human cornea. The reconstructed corneal endothelium was cultured for 2 weeks before transplantation. Five control animals received autologous (n = 1), allogeneic (n = 3), or human xenogeneic (n = 1) native cornea. Two other control animals were grafted with the devitalized carrier only (no cells). Animals were observed daily by slit lamp until euthanatization on day 7. Postmortem analysis included optical coherence tomography (OCT), alizarin red staining, histology, fluorescence microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). RESULTS: Nine of the 11 reconstructed corneal endothelial grafts and all five native (autologous, allogeneic, xenogeneic) control grafts were clear and thin 7 days after grafting. In contrast, the two control grafts consisting of the carrier only (without endothelium) remained thick and opaque. Alizarin red staining, histology, SEM, and TEM showed that the transplanted reconstructed endothelium maintained a normal morphology and ultrastructure and expressed the function-related proteins Na(+)/K(+)-ATPase alpha1, Na(+)/HCO(3), and ZO-1. CONCLUSIONS: This study provides evidence for the short-term (7-day) anatomic and functional success of corneal transplantation with a tissue-engineered corneal endothelium reconstructed on a devitalized carrier.