Abstract
Purpose :
Previously, a tissue engineered corneal endothelium (TECE) consisting of a synthetic hydrogel film and confluent cultured corneal endothelial cells was developed. Here a sheep model of endothelial dystrophy was used to assess the TECE for surgical suitability, toxicity, immunogenicity, and the ability to abate stromal oedema.
Methods :
Confluent ovine corneal endothelial cell (CEC) monolayers were cultured on a 50µm thick synthetic hydrogel films (SHF). The culture protocol was adapted from one used clinically for limbal stem cell transplants. A model of CEC dystrophy was created by surgically removing CEC from a 7mm diameter are of the central cornea of outbred Merino-Dorset ewes of 12-14 months of age. Animal studies were conducted in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. The surgical technique to implant the TECE, which we call tissue-engineered endothelial keratoplasty (TEEK), is essentially the same as DSAEK. Controls included SHF without CEC and TECE not placed over the central endothelial wound. Sheep were observed for at least 21 days post-surgery and scored for inflammation, corneal clarity and oedema using a validated pro-forma. Specifically, oedema was scored on a scale of 0-4, with 0 being completely thin and 4 being maximally thick. Post-mortem histological sections of whole orbs were haematoxylin-eosin stained and scrutinised for evidence of toxicity, immune reaction, and debris in the trabecular meshwork.
Results :
In vivo implantation demonstrated that the TECE was sufficiently robust for surgical implantation. Allogeneic TECE was non-toxic and non-immunogeneic for >20 days (n=13). When placed over the endothelial wound the implant abated oedema (final score 0 or 1, 70% n=10). Histology revealed evidence of SHF degradation (SHF without CEC), or complete degradation of the SHF (TECE animals). Despite degradation of the carrier film no evidence of blockage of the trabecular meshwork was observed in histological sections.
Conclusions :
A SHF carrier with a cultured CEC monolayer may be able to replace the donor tissue lenticule used in DSAEK.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.