This experimental study compared 2 techniques of preservation and transportation of Descemet membrane endothelial keratoplasty (DMEK) grafts.
Study design
DMEK grafts were prepared with an 8.5-mm punch and marked. In group 1, the grafts were tri-folded with endothelium inwards, placed into an IOL cartridge, and preserved in organ culture conditions (n=7). In group 2, the DMEK graft assumed their natural scroll with endothelium outside, placed in hypothermic Optisol solution (Bausch + Lomb), and loaded into a Jones tube (n=7).
After the grafts were shipped from Italy to the U.K., the authors examined the tissue for orientation, endothelial cell density, denuded areas, cell mortality and viability.
Outcomes
The authors did not observe any statistically significant differences in endothelial cell loss or mortality, denuded area or cell viability between the 2 groups. However, this may have been due to a small sample size and there was a trend towards greater endothelial cell damage in the DMEK grafts in group 2.
Limitations
The study was limited by a small sample size. The 2 preservation methods differed in several variables including temperature, preservation medium and folding technique. Thus, it is difficult to draw conclusions on which factors contributed most to endothelial cell damage.
Clinical significance
These findings show that prestripped, preloaded DMEK grafts retained sufficient viable cells for transplantation. The endothelium-in grafts may permit greater flexibility of use due to a longer shelf-life.
These results raise additional interesting questions: What factors contribute most to the increased endothelial cell loss in group 2? How protective is organ culture medium compared to Optisol solution? How much endothelial cell damage results from mechanical trauma due to graft movement during transport, especially when the endothelium is rolled outwards?