Cornea Preservation by Vitrification

点击翻译按钮获取中文摘要

Each year over 33,000 human corneas are transplanted in the United States. However, currently available cornea storage protocols affect deleterious changes in all layers of the cornea, which limit permissible local storage times and largely preclude adequate long-distance cornea sharing. The long-term objective of this grant application is to provide a means of true indefinite-term cornea banking, thus eliminating the shortcomings of current storage protocols and potentially improving outcomes by lessening rejection and late endothelial failure. The proposed vitrification process could allow tens of thousands of natural human corneas, and unlimited numbers of bioartificial corneas, to be exported from the United States to better address the 10 million cases of corneal blindness worldwide. Vitrifcation is a method of cryopreservation that eliminates ice formation and instead induces the formation of a non-damaging glassy state in preserved cells and tissues. This proposal will build on existing results to obtain preliminary 4-month in vivo validation of a new method for human cornea vitrification and to obtain physical data necessary for final clinical design. Preliminary validation will be accomplished using a human-to-monkey xenograft model. To enable transport of vitrified corneas from our lab to the monkey colony, a special temperature-controlled chamber will be fabricated that will allow corneas to be vitrified and maintained at a constant temperature in our laboratory and during travel. Paired human corneas from single donors will be transplanted to both eyes of single recipient vervet monkeys, one cornea having been vitrified, and one stored conventionally in OptisoI-GS. These human corneas will be followed for endothelial cell loss and morphology and for corneal thickness, using a clinical specular microscope, for 4 months. We will also conduct studies to determine the stability of human corneas against ice formation using both physical and biological end points in order to define the design limits of our process. In phase II, we will propose further human-to-monkey xenografts to complete any additional data requirements necessary for approval of human clinical trials, and complete such trials. In phase III we will launch commercial products and services.