Endothelial cell viability after DMEK graft preparation

Abstract

Purpose : To evaluate the effect of graft preparation and organ-culture storage on endothelial cell density (ECD) and viability of Descemet membrane endothelial keratoplasty (DMEK) grafts.

Methods : DMEK grafts (n=27) were prepared at Amnitrans EyeBank Rotterdam from 27 corneas (15 donors) that were eligible for transplantation but could not be allocated due to the Covid-19-related cancellation of elective surgeries. Cell viability (by Calcein-AM staining) and ECD of 5 grafts originally scheduled for transplantation, were evaluated on the originally planned surgery day, whereas 22 grafts from paired donor corneas were evaluated either directly post-preparation or after 3-7 days of storage.

Results : Light microscopy (LM) evaluation of all grafts showed an unremarkable endothelial cell monolayer directly after preparation. However, median viable ECD for the 5 grafts initially allocated for transplantation was 18% (range 9-73%) lower than median LM ECD. For the paired DMEK grafts, viable ECD determined by Calcein-AM staining on the day of graft preparation and after 3-7 days of graft storage showed a median decrease of 1% (mean, 5(±11)%) and 2% (mean, 16(±33)%), respectively. Median % graft area populated by viable cells after preparation and after 3-7 days of graft storage was 88% (mean, 85(±12)%) and 92% (mean, 88(±14)%), respectively.

Conclusions : Loss of viable cells may be observed for some grafts within hours after preparation with insignificant additional ECD changes during 3-7 days of graft storage. Implementing an additional post-preparation step in the eye bank to evaluate cell density before graft release for transplantation may help to reduce postoperative DMEK complications.

This is a 2021 ARVO Annual Meeting abstract.