Evaluation of growth potential of ice-free vitrified heart valves in a pediatric porcine model.

翻译后摘要：心脏瓣膜置换术在儿童是一个严重的问题，因为没有心脏瓣膜植入物 与病人一起成长。目前使用的瓣膜需要随着患者的成长而改变 具有非常高的相关死亡率（~40%）。为了满足这种临床需求，我们正在开创一种 一种全新的方法来提供不断增长的心脏瓣膜植入物，我们称之为部分心脏移植 （PHT）。PHT与心脏移植不同，因为只有包含瓣膜的心脏部分被移植。 移植的根据我们在免疫抑制仔猪中的初步数据，我们最近进行了世界上 2022年4月22日进行了首次人类部分心脏移植，证实了瓣膜生长。然而， 在合适的时间进行捐赠者部分心脏移植的可能性很低。因此，我们建议发展 在主要的儿科心血管医疗中心拥有技术许可证的组织库网络 在全国范围内为临床应用做准备。我们的核心假设是玻璃化和武装的结核杆菌 在生长期儿童原位移植后，可以同时满足其血流动力学和生物学功能。 在第一阶段的提案中，有三个具体目标：首先，我们提出优化短期保存 协议.我们对此目标的工作假设是，PTs将耐受更长时间的死后冷缺血 比完整的心脏多一倍。将评价采购和冷藏对仔猪源性PHTs的影响 通过评估体外活力。这将确定PHT采购的预期地理范围 根据估计的冷藏旅行时间进行解剖。在第二个具体目标中，我们将优化 玻璃化冷冻方案。我们的工作假设，这一目标是，无冰冷冻保存采用 玻璃化冷冻、快速复苏和凋亡抑制技术在成年猪肺动脉心脏中的应用 阀门可以进一步优化，以满足儿科病例所需的较小的PHTs。不同冷冻保护剂加载量 时间、暴露条件和细胞凋亡抑制剂将通过评估体外活力来评价。这 将为儿科结核病患者建立最佳的玻璃化冷冻方案。在最后的目标，我们将评估后- 最佳玻璃化冷冻和冷冻的移植物生长、瓣叶活力和血流动力学功能 冷冻保存的PTH。我们的工作假设，这一目标是，优化的协议将允许玻璃化的PHTs 储存一个月以在体内像新鲜的PHTs一样发挥作用。开发的优化协议， 早期的目标将在猪白细胞抗原匹配的生长免疫抑制仔猪PHT中进行评价 移植模型。这将为未来建立PHT玻璃化，升温和银行化方法 临床应用。

Abstract: Heart valve replacement in children is a serious problem because there are no heart valve implants that grow with the patient. The valves that are currently employed need to be changed as the patient grows with a very high associated mortality rate (~40%). In response to this clinical need, we are pioneering an entirely new approach to deliver growing heart valve implants, which we are calling partial heart transplantation (PHT). PHT differs from heart transplantation because only the part of the heart containing a valve is transplanted. Based on our preliminary data in immunosuppressed piglets, we recently performed the world’s first human partial heart transplant on 4/22/2022 with demonstrated valve growth. However, the chance of a donor partial heart transplant being available at just the right time is low. Therefore, we propose development of a network of tissue banks with technology licenses at major pediatric cardiovascular medical centers nationwide in preparation for clinical application. Our central hypothesis is that vitrified and nanowarmed PHTs can fulfill both their hemodynamic and biological functions after orthotopic transplantation in growing children. In this Phase I proposal there are three specific aims: First we propose optimization of short-term preservation protocols. Our working hypothesis for this aim is that PHTs will tolerate longer post-mortem cold ischemic times than intact hearts. The impact of procurement and refrigeration on piglet-derived PHTs will be evaluated by assessment of viability in vitro. This will establish the anticipated geographic range for PHT procurement after dissection based upon estimated refrigerated travel time. In the second specific aim we will optimize vitrification protocols for PHTs. Our working hypothesis for this aim is that ice-free cryo-preservation employing tissue vitrification, rapid nanowarming and apoptosis inhibition developed for adult porcine pulmonary heart valves can be further optimized for smaller PHTs required for pediatric cases. Different cryoprotectant loading times, exposure conditions, and apoptosis inhibitors will be evaluated by assessment of viability in vitro. This will establish the optimal vitrification protocol for pediatric PHTs. In the final aim we will evaluate post- transplant growth, leaflet viability and hemodynamic function of optimally vitrified and nanowarmed cryopreserved PHTs. Our working hypothesis for this aim is that optimized protocols will allow vitrified PHTs that were banked for one month to function in vivo like fresh PHTs. The optimized protocols developed in the earlier aims will be evaluated in a swine leukocyte antigen matched growing immunosuppressed piglet PHT model by transplantation. This will establish the PHT vitrification, warming, and banking methods for future clinical application.