Cornea Preservation by Vitrification

在美国，每年有超过33，000例人类角膜移植。然而，目前可用的角膜存储协议影响角膜的所有层中的有害变化，这限制了可允许的本地存储时间并且在很大程度上排除了足够的远距离角膜共享。这项拨款申请的长期目标是提供一种真正的不确定期限角膜银行的手段，从而消除当前存储协议的缺点，并通过减少排斥反应和晚期内皮衰竭来潜在地改善结果。拟议的玻璃化过程可以允许从美国出口数万个天然人类角膜和无限数量的生物人工角膜，以更好地解决全球1000万角膜失明病例。玻璃化法是一种低温保存方法，它消除了冰的形成，而是诱导保存中形成非破坏性的玻璃态。 细胞和组织。该提案将建立在现有结果的基础上，以获得对人类角膜玻璃化冷冻新方法的初步4个月体内验证，并获得最终临床设计所需的物理数据。将使用人-猴异种移植模型完成初步验证。为了能够将玻璃化角膜从我们的实验室运输到猴群，将制造一个特殊的温度控制室，允许角膜在我们的实验室和旅行期间被玻璃化并保持在恒定的温度下。将来自单个供体的成对人角膜移植到单个受体黑长尾猴的双眼中，一个角膜已经玻璃化，另一个常规储存在OptisoI-GS中。将跟踪这些人角膜的内皮细胞损失和形态以及角膜厚度， 使用临床镜面反射显微镜，持续4个月。我们还将进行研究，使用物理和生物终点来确定人类角膜对冰形成的稳定性，以确定我们工艺的设计限值。在第二阶段，我们将提出进一步的人-猴异种移植，以完成批准人体临床试验所需的任何额外数据要求，并完成此类试验。在第三阶段，我们将推出商业产品和服务。

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.