Ex‐vivo porcine corneal storage using an innovative bioreactor

Purpose There is no animal model of medium‐term corneal storage. Unlike humans, animal corneas rapidly and dramatically swell and lose their transparency, suggesting that the passive eye banking technique is not adapted. Moreover, immersion in standard organ culture (stdOC) medium is not fully adapted for epithelial maintenance. Aim: To reproduce physiological parameters to improve storage of animal corneas. Methods We designed a bioreactor (BR) that reproduces the intraocular pressure in the endothelial chamber while allowing renewing of the medium. We mimic blinking in the epithelial chamber, with an air‐lifting system. Forty‐one porcine corneas were stored either in the BR with 20 mmHg in the endothelial chamber, or in stdOC vials at 31°C for 7 days. Endothelial viability, endothelial cell density (ECD) were assessed after labeling with Hoechst‐Ethidium‐Calcein. Transparency was assessed with a custom‐made device and thickness by OCT. Limbus and central epithelial integrity was assessed using immunostaining of stem cells and differentiation markers. Results In stdOC, corneas were edematous (2,878 ± 623 μm), had reduced endothelial viability (44 ± 16%), and lost most of the epithelial layers. In the BR, they were thinner (1,274 ± 154 μm), had better endothelial viability (94 ± 3%) and their epithelium was multilayered and mature. The epithelial stem cells seemed preserved. Conclusions The porcine version of BR mimics physiological conditions and improves corneal storage. It could be a new model of eye banking and a powerful experimental platform to study corneal physiopathology.