Storage of Porcine Cornea in an Innovative Bioreactor

Purpose: To quantify cell survival and tissue structure preservation of porcine cornea stored in a bioreactor (BR) that recreates a transcorneal pressure gradient equivalent to intraocular pressure (IOP) and renews the medium. Methods: A BR comprising endothelial and epithelial chambers was machined in a biocompatible material. The porcine cornea, securely held, separated the chambers. Medium flow and pressure inside the endothelial chamber were maintained by a peristaltic pump. In the epithelial chamber, the corneal surface was alternatively exposed to air and a specific medium. Two transparent windows allowed thickness measurement by optical coherence tomography without opening the BR. Porcine corneas stored in the BR-on (pressure 20 mm Hg, flow 5 μL/min, temperature 31°C) were compared with (1) BR-off (no pressure or flow); (2) organ culture; and (3) Petri dish with agar on the endothelial side. Epithelial and limbal structure and differentiation, corneal transparency and thickness, and endothelial viability were compared after 7 days of storage and with fresh corneas. Results: Corneas stored in the BR-on were thinner and more transparent than those stored with the other methods. The BR-on preserved a stratified and differentiated (K3/K12+) corneal epithelium and undifferentiated basal limbal cells with stemness markers (K3/K12-; ABCB5, K14, p75+), as well as endothelial integrity. Conclusions: By recreating equivalent IOP and medium renewal, the BR obtained unprecedented storage quality of porcine corneas and preserved their main epithelial, limbal, and endothelial characteristics.