New Solutions to Improve Islet Recovery after Machine Preservation of Pancreas

描述（由申请人提供）：由于使用“埃德蒙顿方案”获得的结果，用于临床治疗I型糖尿病的朗格汉斯胰岛移植重新引起了人们的兴趣。然而，目前，用于胰岛分离和移植的供体胰腺的采购尚处于起步阶段。大多数偏远供体的胰腺都不能获得，因为有理由担心在运往胰岛隔离和移植中心的过程中会出现死后缺血。灌注/保存技术已被证明在肾移植中避免缺血性损伤方面具有重要作用。本提案旨在将这种方法应用于保存和获取可移植的胰岛。本提案的主要目的是使用最先进的灌注技术和新的保存溶液来验证机器灌注可以提高由缺血胰腺制备的胰岛的产量和活力的假设。为此，在之前的一项研究中，研究人员设计并构建了胰腺转运体原型（PTR），并利用猪模型证明了在2-7℃条件下24小时灌注保存的可行性。这超过了文献记载的供体胰腺安全、静态冷藏的目前临床极限16h。在此，我们提出一项补充研究，以解决该技术进一步发展的第二个重要因素，即灌注液的设计和优化，以最大限度地提高低温机器灌注保存后离体胰岛的产量和活力。更具体地说，在I期研究中，一种新的专有溶液（Unisol）将与目前标准的器官保存溶液（KPS1和UW Viaspan）进行比较，用于新鲜猪胰腺的24小时保存。这项新技术的安全性和有效性将在II期研究中进一步研究，其中用于在PTR中灌注胰腺的溶液的设计将在四个特定目标中进行优化。第一步将是使用高通量测定系统来选择细胞保护添加剂，以纳入基础灌注液。第二步将需要胰腺灌注液与添加细胞保护鸡尾酒的比较，用于机器保存新鲜胰腺，没有热缺血。然后利用优化后的灌注液评估冷灌注时间（24和48h）和热缺血时间（60min）对胰岛分离参数的相互作用，确定潜在的临床应用范围和技术限制。最后，不适合移植的人类胰腺将用于该技术的临床前验证。预计胰腺转运体和胰腺灌注方案的可用性将允许在美国使用大多数（如果不是全部的话）适合移植的胰腺。此外，PTR可能允许胰岛分离库进行长期储存。储存将为供体和受体更好地匹配HLA提供时间，提供现成的可用性，并在移植前进行质量保证/控制程序。该研究项目得到了三家主要临床中心的合作支持，这些中心对该灌注技术的验证感兴趣，以供未来使用。

DESCRIPTION (provided by applicant): Transplantation of islets of Langerhans for the clinical treatment of Type I diabetes has had a resurgence of interest due to results obtained using the "Edmonton protocol". However, at this time, procurement of donor pancreases for islet isolation and transplantation is in its infancy. Most pancreases at more remote donor sites are not procured due to justified concerns about post-mortem ischemia during transport to the islet isolation and transplant center. Perfusion/preservation technology has been shown to have a major impact in circumventing ischemic injury in kidney transplantation. This proposal seeks to apply this approach to the preservation and procurement of viable islets for transplantation. The primary objective of this proposal is to use state-of-the-art perfusion technology and new preservation solutions to test the hypothesis that machine perfusion can improve the yield and viability of islets prepared from ischemic pancreases. To this end, a prototype pancreas transporter (PTR) has been designed and constructed in a previous study that demonstrated the feasibility of 24h perfusion preservation at 2-7 degrees C using a porcine model. This exceeds the 16h documented to be the present clinical limits of safe, static cold storage of donor pancreata. Here we propose a complimentary study to address the second important factor for further development of this technology, namely the design and optimization of the perfusate to maximize the yield and viability of isolated islets after hypothermic machine perfusion preservation. More specifically, in the Phase I study a new proprietary solution (Unisol) will be compared with current standard organ preservation solutions (KPS1 and UW Viaspan) for 24h preservation of fresh porcine pancreata. The safety and efficacy of this new technology will be further investigated during a Phase II study in which the design of the solution used to perfuse the pancreas in the PTR will be optimized in four specific aims. The first step will be to use a system of high throughput assays to select cytoprotective additives to be incorporated into the base perfusates. The second step will entail a comparison of pancreas perfusates with the addition of the cytoprotective cocktail for machine preservation of fresh pancreata with no warm ischemia. Then the interaction between cold perfusion time (24 and 48h) and warm ischemia time (up to 60 min) on porcine islet isolation parameters will be evaluated using the optimized perfusate for the definition of the potential clinical scope and technology limits. Finally, human pancreases that are unsuitable for transplantation will be employed for pre-clinical validation of this technology. It is anticipated that the availability of a pancreas transporter and pancreas perfusion protocols will permit utilization of most, if not all, pancreases suitable for transplantation in the U.S. Furthermore, the PTR may permit islet isolation banking for long-term storage. Banking would allow time for better HLA matching of donors to recipients, off-the-shelf availability, and enable quality assurance/control procedures to be conducted prior to transplantation. This research program is supported by collaboration with three major clinical centers interested in validation of this perfusion technology for their future use. Project Narrative: Insulin-dependent diabetes is one of the major health problems worldwide and there is now a great deal of interest in developing an option for a potential cure by transplantation of islet cells isolated from a donor pancreas. A critical component of this approach is the availability of sufficient high quality islets to reverse diabetes in the patient. This research is focused on the development of new technologies (a perfusion machine and protective solutions) for improving the quality of pancreas preservation to yield larger numbers of high functioning islet cells.