One year stored corneas: is it possible?

Abstract

AbstractPurpose To evaluate the endothelial characteristics after very long term organ culture (OC) of human corneas.Methods Human corneas with initial endothelial cell density (ECD) >2000 cells/mm2 were stored at 31°C in sealed flasks containing 100mL of a commercial medium with 2% foetal calf serum (CorneaMax, Eurobio, France): 6 for 3‐6 months (M), 7 for 6‐12 M and 5 for more than 12 M. The medium was renewed every 2 M. Transparency was quantified by analysis of modulation and contrast transfer functions. On one half of each cornea, ECD and EC morphology were analysed by image analysis (CellP‐Olympus, and SambaCornea‐TribVn) after alizarin red staining and flat mounting. On the other half of the cornea, EC differentiation status (NaK ATPase, ZO‐1, JAM‐1) and proliferative capacity (Ki67, Click‐it EdU) were studied by immunostaining in flat mounted corneas (He, MolVis2011;17:3494 and He, StemCells2012 in press). Epithelial cells and stroma were observed by histology on cross sections stained with Hematein/Eosin/Safran and by transmission electron microscopyResults Corneal transparency and ECD decreased after very long‐term OC, but were partially preserved. ECD was about 1200, 800 and 400 cell/mm2 after respectively 3, 6 and 12 months. Morphology and differentiation of residual EC remained nevertheless almost preserved. The epithelium lost its multilayered organizationConclusion Corneal cells, particularly EC, can survive for a very long time in the rustic environment of OC, suggesting that they are well equipped against environmental stress and cell death. The improvement of storage process and/or storage medium could potentially allow very long term storage without significant attrition of graft quality and therefore provide corneas suitable for graft