The fate of preserved and transplanted human corneal entothelium

This paper evaluates the numbers of corneal endothelial cells that survive transplantation. The donor endothelium was photographed with a specular microscope both before enucleation and in situ after keratoplasty. The cell density was measured in 16 corneas from donors with choroidal melanoma. Of these donor corneas 12 were cryopreserved, two were preserved in McCarey and Kaufman's (M-K) medium and two were transplanted fresh. The average follow-up period after keratoplasty was 11 months. The mean endothelial cell loss for the whole series was found to be 49%. The mean cell loss for the cryopreserved corneas was 55%. In the four other recipients, with donor corneas that had been stored in M-K medium or transplanted fresh, the mean cell loss was 32%. The corneas preserved in M-K medium had the highest cell density in the transplants, with cell losses of 21 and 22%. Cell losses in the two corneas transplanted fresh were 40 and 44%. Cell losses, in the cryopreserved grafts had a wide variation, 33-77%. No correlation could be found between cell loss and either the age of the donor or the duration of perservation. Freezing and thawing was found to damage a proportion of the cells so that they did not stain with para-nitro-blue tetrazolium (p-NBT) after preservation. Transmission and scanning electron microscopy also revealed changes in the intercellular spaces and some cell disruption in cryopreserved grafts.