Tissue Engineering Cornea Replacements

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DESCRIPTION (provided by applicant): Corneal damage causes significant vision loss, second only to cataracts. Corneal replacement is a developing technology that is becoming a necessity for many patients due to disease (e.g., herpes infection), complications from LASIK, hereditary problems (e.g., Fuch's disease) and complications from related surgeries (e.g., cataracts). Current strategies employed for corneal grafting primarily make use of synthetic or allergenic materials. While these strategies are partially effective, the downside is that they can stimulate host immune responses resulting in tissue rejection or carry the risk of transferring diseases from unhealthy donor organs. These complications are compounded by the growing use of corrective eye surgery which renders corneas unsuitable for grafting, further reducing the availability of acceptable allergenic supplies. The development of a human cornea replacement that alleviates these shortcomings is urgently needed and this is the goal of the proposed program. The hypothesis is that silk protein-biomaterial lamellar systems coupled with cornea- specific cells can be bioengineered to match in vivo corneal properties and meet functional requirements. The proposed system will exploit the novel material and biological features of silk, including surface micropatterning to guide cells and extracellular matrix deposition, slow degradation, biocompatibility, optical transparency and mechanical durability for handling, suturing and tolerating ocular pressures. A cornea tissue system that slowly degrades to allow for host native tissue replacement would offer a significant and novel advancement in corneal transplantation technology. In combination with corneal derived stem cells, we anticipate optimizing cell-silk interactions first in 2D and then as 3D lamellar structures. Functional assessments of the performance of these cornea tissue systems (mechanical, optical) will follow as will optimization of surgical methods and host integration. The outcome of the proposed program will be the in vitro optimization of human cornea replacements and in vivo assessments of utility. The research team has the required background with the materials, cells and systems of study to support the program plans, and the data collected during our R21 program provides supporting documentation for all aspects of the proposed study. Our approach to addressing this need is unique and offers novel methodology to meet the ever-growing demands for corneal replacements. Successful development of an in vitro source will ameliorate the current shortages and provide a much-needed alternative for patients. PUBLIC HEALTH RELEVANCE: Corneal diseases are responsible for extensive vision loss throughout the world, second only to cataracts. A number of sources are currently available for cornea replacement and include allergenic and synthetic materials. However, each of these options has problems, including disease transmission; inflammatory responses post implantation and poor material performance that may result in tissue rejection or device failure. These concerns are compounded by the growing demand for corrective surgery which renders would-be donor corneas unsuitable for grafting. Thus, a crucial need exists to develop new cornea replacement devices that provide the required material and biological properties to address the above limitations, while also offering an integration strategy that allows the device to be replaced by the patients' native tissues.