Apoptosis in the endothelium of human corneas for transplantation.

PURPOSE To determine whether endothelial cell loss of human corneas stored in organ culture before transplantation is due to apoptosis. METHODS The corneal endothelium of human corneas, stored in organ culture at 34 degrees C for varying periods of time, were analyzed for the presence of apoptotic cells using the TdT-mediated dUTP nick-end labeling (TUNEL) technique. Corneal endothelial cell apoptosis was confirmed by Hoechst staining and immunolabeling with anti-caspase 3 active antibody. RESULTS Apoptotic cells were identified in the corneal endothelium of human organ cultured corneas: their number and distribution demonstrated a close correlation with corneal folding and overall quality of the corneal endothelium. TUNEL-positive labeling of cells was confirmed as apoptotic by the presence of morphologic nuclear alterations identified by Hoechst staining and the presence of immunostaining for caspase-3 activity. Corneal endothelial cell apoptosis was independent of cause of donor death, death to enucleation time, and death to culture times. CONCLUSIONS Corneal endothelial cell apoptosis appears to determine the suitability of a cornea for transplantation.