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) t echnique. Corneal endothelial cell apoptosis was confirmed by Hoechst stain ing and immunolabeling with anti-caspase 3 active antibody. RESULTS. Apoptotic cells were identified in the corneal endothelium of huma n organ cultured corneas: their number and distribution demonstrated a clos e correlation with corneal folding and overall quality of the corneal endot helium. 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 endothel ial cell apoptosis was independent of cause of donor death, death to enucle ation time, and death to culture times. CONCLUSIONS. Corneal endothelial cell apoptosis appears to determine the su itability of a cornea for transplantation.