siRNA Protection of Composite Islet Kidney Transplant in Baboons

 描述(申请人提供)：这项提案的总体目标是结合两项新技术，以提高胰岛移植治疗1型糖尿病的能力。第一种技术涉及以复合胰岛-肾脏(IK)的形式移植带血管的胰岛，该技术具有治愈猪和狒狒模型中糖尿病和肾功能衰竭的能力，正如我们最近所展示的那样。在该方案中，首先将部分胰腺切除后获得的胰岛移植到自体肾被膜下，以允许重新血管形成，然后将复合胰岛-肾移植到接受糖尿病的动物身上。尽管复合自体IK技术大大降低了免疫事件对移植物的损伤程度，但由于缺氧和缺血丢失，复合IK中仍有相当大的胰岛丢失，最终需要70%的活体胰腺切除。为了提高IK复合体的存活率并显著减少供体胰岛的数量，我们建议使用第二种技术，该技术利用无缝隙磁性纳米颗粒作为siRNA的载体，当siRNA在胰岛细胞中积累时，可以在IK产生之前沉默导致胰岛损伤的基因。除了作为siRNA载体外，这些抗辐射纳米颗粒还可以用作体内磁共振成像(MRI)记者，纵向和非侵入性地提供移植物体积的信息。我们之前已经在小鼠移植模型中展示了这项技术在提高移植物存活率方面的适用性。在这项应用中，我们建议在制造IK复合体之前，通过向胰岛递送靶向与细胞凋亡有关的基因的siRNA纳米颗粒探针，来研究这种方法在非人类灵长类动物中的临床前应用。具体地说，我们将把caspase 3、caspase 8和Fas单独或联合作为最重要的细胞凋亡调节因子。由于磁性纳米颗粒长期保留在胰岛中，体内磁共振成像将用于监测自体IK移植物的体积，随后将对受体糖尿病动物的IK移植进行连续成像。我们预计，通过靶向凋亡基因，我们将减少自体IK复合体中胰岛的损伤，从而减少IK复合体纠正糖尿病受体高血糖所需的供体胰岛数量。通过MN-siRNA技术进一步减少切除的胰腺数量和无创性地评估胰岛体积，该方法将更有利于活体供体IK移植的临床应用。

 DESCRIPTION (provided by applicant): The overall goal of this proposal is to combine two novel technologies in order to improve the capacity of pancreatic islet transplants to cure type 1 diabetes. The first technology involves transplantation of vascularized islets in the form of composite islet-kidneys (IK), which has the capacity to cure both diabetes and renal failure in swine and baboon model as we have recently demonstrated. In this protocol, pancreatic islets obtained after partial pancreatectomy are first transplanted under the autologous kidney capsule to allow for re- vascularization, and then the composite islet-kidney is transplanted in a recipien diabetic animal. Though composite autologous IK technology substantially reduces the extent of graft damage due to immunologic events, there is still considerable islet loss in IK composite due to hypoxia and ischemic loss ultimately requiring a 70% pancreatectomy of the living donor. To improve IK composite survival and significantly reduce the number of donor islets we propose to use the second technology that utilizes theranostic magnetic nanoparticles as carriers for siRNA, which upon accumulation in islet cells could silence genes responsible for islet damage prior to IK creation. In addition to serving as siRNA carriers these theranostic nanoparticles could be used as in vivo magnetic resonance imaging (MRI) reporters providing information about graft volume longitudinally and non-invasively. We have previously shown the applicability of this technology for improving graft survival in a mouse model of transplantation. In this application we propose to investigate pre-clinical utility of this approach in non-human primates by delivering siRNA-nanoparticle probes targeting genes implicated in apoptosis to islets prior to creating the IK composite. Specifically, we will target caspase 3, caspase 8 and Fas, alone or in combination, as the most important mediators of apoptosis. In vivo MR imaging will be used to monitor autologous IK graft volume followed by continuous imaging of the IK transplant in recipient diabetic animals since magnetic nanoparticles are retained in the islets long term. We expect that by targeting apoptotic genes we will reduce the damage to the islets in autologous IK composite and as a consequence will reduce the number of donor islets required for IK composite to correct hyperglycemia in diabetic recipients. By further minimizing the amount of excised pancreas and non-invasive assessment of islets volume by the MN-siRNA technology, the clinical applicability of this procedure will be more favorable for living donor IK transplantation.