Abstract
Purpose: :
Dehydration of corneas prior to transplantation using dextran 500 causes endothelial cell loss due to osmotic stress and cellular toxicity. Hydroxyethyl starch 130 (HES) has been suggested as a permanent dehydrating agent in long–term cornea culture. The fetal calf serum (FCS) present in standard cornea storage media cannot be completely defined and standardized from biochemical and microbiological point of view. The purpose of this study is to compare corneas stored in a fully synthetic medium containing HES and insulin with corneas stored and dehydrated under standard conditions.
Methods: :
Six pairs of human donor corneas were randomized into 2 groups and cultivated in MEM with antibiotics and different media additives at 31°C for 16 days. Media contained 2% FCS in group A, and 7,5 % HES plus 1mU/l recombinant human insulin in group B. On day 15, corneas from group A were placed in dehydration medium (MEM + antibiotics + 2% FCS + 5% dextran 500). Endothelial cell density and cell morphology were investigated at the beginning and end of culture. Corneal thickness was assessed by pachymetry. Histology of the tissues was performed. Statistical analysis was performed using the Wilcoxon paired signed rank test.
Results: :
Initial endothelial cell counts were 2649 + 211 and 2740 + 317 /mm2 in groups A and B respectively (difference n.s.). Cell count after culture was 2389 + 343 and 2610 + 264 /mm2 in groups A and B respectively (difference p<0.05). Cell loss was significant in group A (p<0.05) but not B. Corneal thickness on day 15 was 882 + 119 and 914 + 119 µm in groups A and B, respectively (n.s.). No significant differences in endothelial cell morphology scores were seen.
Conclusions: :
The synthetic medium with 7,5% HES and insulin used in this study led to significantly improved endothelial cell survival during cornea culture. Other parameters did not differ from controls. It has previously been shown that the metabolic status of corneas cultivated with HES 130 improves during culture. It is thus feasible to store donor corneas in fully synthetic medium without FCS for 16 days, without the need for dehydration, with improved endothelial cell survival as well as transplant availability.
Keywords: cornea: storage • cornea: endothelium