Purpose:
To investigate whether an extracellular matrix (ECM) membrane has adequate mechanical and biological properties to be used as a limbal stem cell (LSC) carrier for the regeneration of the corneal epithelium.
Methods:
A novel ECM membrane was manufactured using cultured porcine chondrocytes and molded to have a convexity analogous to that of the natural cornea. The mechanical properties were measured and compared to those of commercially available denuded human amniotic membrane (HAM). Rabbit LSCs were labeled with PKH26 dye, and cultivated on the ECM membrane or HAM. The cell attachment and proliferation rates were evaluated, and then the LSC-ECM membrane construct was attached to a denuded rabbit corneal button and implanted onto the back of an athymic mouse. At 3 weeks after implantation, the grafts were analyzed by transmission electron microscopy (TEM), histology, and immunohistochemical staining of AE-5 and mucin-5AC.
Results:
The ECM membrane had a base curve that corresponded to the surface curvature of the natural cornea, and it was 1.5-times (15 µm) thicker and exhibited higher light transmittance than HAM; moreover, there were no significant differences in cytocompatibility. On ex vivo cultivation, a new epithelium with PKH-labeled cells was formed on the denuded corneal button attached to the LSC-ECM membrane construct. TEM images of the graft showed a continuous cell layer covering the stroma with good cell-to-cell contact. Histological examination showed that the newly formed epithelium was similar to the normal cornea and expressed AE-5 but mucin-5A, which showed corneal epithelial specific phenotype.
Conclusions:
The ECM membrane was fabricated in the form of a contact lens to ensure that it fit to the corneal surface and possesses the mechanical properties and cytocompatibility required for LSC transplantation. The results of ex vivo implantation demonstrated that the ECM membrane can be used as an LSC cell carrier for repairing the corneal epithelium.
Keywords: cornea: epithelium • extracellular matrix • transplantation