Influence of temporary hypothermia on corneal endothelial cell density during organ culture preservation.
OBJECTIVE
To evaluate temporary exposure to hypothermia for its effects on endothelial cell density of porcine corneas in dextran containing organ-culture medium, with regard to possible negative influences of low temperatures during the transport of corneal grafts.


METHODS
Two groups of central discs from pig corneas (diameter 8 mm) were first organ-cultured (MEM with 6% dextran 500) for 24 hours at 32 degrees C. Twelve corneas were exposed to 4 degrees C in group 1 for 12 hours and to 21 degrees C in group 2 for 48 hours each. The paired corneal discs were not treated, and served as controls. After further organ culture of all corneas for 48 hours at 32 degrees C to allow regenerative processes, corneal endothelium was stained with alizarin red S and examined by light microscopy. The endothelial cell densities were determined manually on three central images.


RESULTS
Exposure for 12 hours to 4 degrees C as well as for 48 hours to 21 degrees C induced an endothelial cell loss of 0.3% and 1.8% respectively. Statistical analysis showed no significant difference (p = 0.680) of the endothelial cell density between corneas exposed to 4 degrees C and the control corneas (4166 +/- 389 cells/mm(2) and 4177 +/- 407 cells/mm(2) respectively). Despite the minor cell loss, the difference of the endothelial cell density between corneas exposed to 21 degrees C and the control corneas (4085 +/- 260 cells/mm(2) and 4159 +/- 312 cells/mm(2) respectively) was statistically significant (p = 0.025).


CONCLUSIONS
Exposure of organ-cultured porcine corneas in dextran containing medium to 4 degrees C for 12 hours and 21 degrees C for 48 hours does not compromise the endothelial cell density of donor corneas in a clinically relevant manner. A storage of corneal grafts at temperatures down to 4 degrees C for 12 hours, as might be the case during transport from the cornea bank to the ocular surgeon, does not seem to damage the endothelial cell layer.
Schroeter
Jan
J
Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany. jan.schroeter@charite.de
Meltendorf
Christian
C
Ohrloff
Christian
C
Rieck
Peter
P
D000818:Animals; D002452:Cell Count; D003315:Cornea; D015925:Cryopreservation; D016895:Culture Media, Serum-Free; D004728:Endothelium, Corneal / Q000473:pathology*; D005125:Eye Banks; D007036:Hypothermia, Induced; D009924:Organ Culture Techniques; D009926:Organ Preservation; D013552:Swine
D016895:Culture Media, Serum-Free