Decellularized Bovine Corneal Posterior Lamellae as Carrier Matrix for Cultivated Human Corneal Endothelial Cells

Purpose: To evaluate the potential of decellularized bovine corneas (DBCs) as a carrier matrix for cultivating and transplanting human corneal endothelial cells (HCECs). Methods: Posterior lamellae of ten bovine corneas were decellularized using ethylene diamin tetra-acetic acid (EDTA, 0.1%), aprotinin (10 KIU/mL) and 0.3% sodium dodecyl sulphate (SDS). Hematoxylin-eosin (HE) and 4,6-diamidino-2-phenylindole (DAPI) staining was done to confirm the absence of bovine cells. Quantitative analysis was performed to determine levels of desoxyribonucleic acid (DNA) using a DNA Purification Kit. HCECs were harvested from human donor eyes and seeded on the Descemet's membrane of the DBCs. Cell morphology was assessed after 6 h of incubation, and at days 1, 4, 7, 10 and 14. Expression of zonula occludens-1 (ZO-1), connexin-43 (CX-43), Na+/K+-adenosine triphosphatase (Na+/K+-ATPase), natrium hydrogen carboanhydrase (Na+/HCO3-), collagen type VIII, collagen type IV and cytokeratin-3 (AE5) were analyzed by immunohistochemistry. Results: HE staining and DAPI staining showed that bovine cells were substantially removed from the stroma and Descemet's membrane. A significant DNA reduction (mean before decelluraziation 365.3 +/- 88.6 ng/mg, mean after decelluarization 23.2 +/- 7.9 ng/mg, p < 0.001) was observed. HCECs formed a continuous, viable, predominantly polygonal monolayer with a mean cell density of 2380 +/- 179 cells/mm(2) on DBCs. Immunohistochemistry analysis demonstrated positive staining for AE5, collagen type VIII, ZO-1, CX-43, Na+/HCO3-, and Na+/K+-ATPase. Conclusions: Phenotypical properties of HCECs on DBCs imply that the HCEC sheets are capable of maintaining an intact barrier and ionic pump function in vitro. DBCs might, therefore, be a promising scaffold for ex vivo expansion of HCECs. This xenogeneic substrate might be used for therapy of isolated corneal endothelial diseases.