Damage to corneal endothelial cells by lysosomal enzymes in stored human eyes

We wished to see if the concentration of lysosomal enzymes in the aqueous humour had any relation to the number of dead corneal endothelial cells in stored eyes from human donors. Forty pairs of eyes were obtained: one eye of each pair was tested immediately and the other was tested after storage in a moist chamber at 4 degrees C for up to 10 days. The aqueous humour of each eye was aspirated and the concentration of acid phosphatase (a marker of lysosomal hydrolytic enzymes) was measured. Simultaneously the numbers of dead and living cells per unit area of the corneal endothelium were counted following their staining with trypan blue and p-nitroblue tetrazolium respectively. As the storage time increased, the concentration of acid phosphatase in the aqueous humour increased and the number of living corneal endothelial cells decreased. The number of living cells decreased to about 50% at an average enzyme concentration of 9 X 10(-3) muM/h. The eyes stored for less than 3 days were the least damaged.