ENERGY RECRUITMENT OF THE HUMAN CORNEA DURING STORAGE IN DIFFERENT SYSTEMS

Background There are two well known systems to culture human corneas p rior to transplantation. First, corneal storage at 4 degrees C especia lly in Optisol medium. Second, organ-culture at physiological temperat ures in a modified minimal essential medium (MEM). In the cold storage system the number of endothelial cells after storage might be overest imated because the damaged cells are not able to leave the monolayer. It has been supposed that the lack in energy recruitment is the main r eason for that, but has not been proven yet. It was the purpose of thi s study to describe the energy status of the human cornea after storag e in both systems. Materials and Methods 32 human corneas were investi gated. They were stored for 7 days in Optisol, and for 7 days in MEM p lus 1 day in MEM supplemented with 5% dextran 500 and 12 days in modif ied MEM plus 1 day in MEM supplemented with 5% dextran 500. The endoth elial cell density (ECD) as well as the hydration were determined. Glu cose, lactate, ATP, ADP and AMP were measured to reflect the energy st atus. Results Hydration was comparable in all three groups. ECD was sl ightly higher in Optisol stored corneas, although the amount of damage d cells was much higher. Optisol stored corneas showed a severe anaero bic situation, especially lacate concentrations were increased. In con trast ATP and ADP concentrations were twice as high in MEM than in Opt isol stored corneas. Discussion The severe anaerobic situation in Opti sol stored corneas leads to a lack in energy recruitment. This reduces the ability of cell function (mitosis) and the function of the monola yer (migration, elimination). Whether these changes are reversible aft er transplantation has to be determined in future.