An engineered collagen sponge matrix as an in vitro model for corneal wound healing

Corneal opacification secondary to a variety of complications is a leading cause of blindness in the world. Successful corneal wound healing is essential for the outcome of corneal transplants as well as corneal surgeries to improve vision, however, the specific mechanisms of corneal wound healing are unknown. The goal of this project is to investigate a collagen sponge matrix as a novel substrate for the investigation of corneal wound healing as well as a scaffold for corneal wound healing in vivo. To this end, we have studied the epithelialization of the collagen sponge matrix, the corneal keratocyte response to the collagen sponge matrix and the performance of the collagen sponge matrix in vivo. Our studies found that the quality and morphology of the epithelial cell layer was influenced by soluble factors produced by endothelial cells. In addition, the morphology of the basal layer of epithelial cells was influenced by the presence of keratocytes in the culture. Keratocytes grown in collagen sponge matrix have the ability to contract the matrix. This contraction is inversely related to the transparency of the tissue construct. We have determined that transparency can be modulated by altering the composition of the collagen sponge matrix. This study also investigated the phenotype of the stromal keratocytes and determined that when cultured in a collagen sponge, the cells exhibit the wound healing myofibroblast phenotype. The potential exists for altering the phenotype of corneal fibroblasts to improve the transparency of the overall tissue construct. In vivo investigation of the collagen sponge matrix revealed that the material was incorporated into the cornea and completely reepithelialized. An acute inflammatory response potentially resulting from migrating epithelium or depth of the incisions could be improved in the future by the use of anti-inflammatory agents. Our culture system provides an excellent in vitro model for corneal wound healing and has the potential to be used as a corneal wound healing bandage.