Regeneration with proliferation of the endothelium of cultured human donor corneas with extended postmortem time.
OBJECTIVE
To examine the endothelium of donor corneas with extended postmortem time for survival and reparative mechanisms in an eye bank organ culture storage system.


METHODS
We obtained 14 pairs of donor corneas with a postmortem time ranging from 29 to 163 hours. One cornea of a pair was immediately fixed for the study of structural changes postmortem and to serve as a control. The second was stored in organ culture for 3 days and thereafter fixed to be studied for reparative processes. Examination was done with light microscopy and scanning electron microscopy. Immunohistochemical staining with antibodies against proliferating cell nuclear antigen, Ki-67, and n-cadherin was performed to examine for cell proliferation and to characterize the cells.


RESULTS
The control corneas showed increasing endothelial cell damage with increasing postmortem time. After 5-7 days postmortem, most cells were structurally damaged. After 3 days in organ culture, all corneas acquired an endothelial covering of the posterior surface, with cells, suggesting proliferation in both scanning preparations and in cross-sections. Positive endothelial cell staining with proliferating cell nuclear antigen was found in all cultured corneas. Ki-67 staining of the endothelium was found in 9 of the cultured corneas.


CONCLUSIONS
The study showed survival of the corneal endothelium up to 7 days postmortem, and accordingly, the potential clinical use of donor corneas with extended postmortem time. Our results furthermore suggest that repair of the endothelium in donor corneas during organ culture storage occurs also by proliferation and not only by migration and enlargement of existing cells. If we uncover the mechanisms regulating cell proliferation in corneal endothelium, it should be possible to develop better storage methods of corneal transplants to improve quality and supply.
Slettedal
Jon Klokk
JK
Center for Eye Research, Department of Ophthalmology, Ullevaal University Hospital, Oslo, Norway. jon.klokk.slettedal@gmail.com
Lyberg
Torstein
T
Røger
Magnus
M
Beraki
Kahsai
K
Ramstad
Hanne
H
Nicolaissen
Bjørn
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015820:Cadherins / Q000378:metabolism; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology; D004728:Endothelium, Corneal / Q000502:physiology* / Q000648:ultrastructure*; D005125:Eye Banks; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D009924:Organ Culture Techniques; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D012038:Regeneration / Q000502:physiology*; D013997:Time Factors; D014019:Tissue Donors
D015820:Cadherins; D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen