siRNA Protection of Composite Islet Kidney Transplant in Baboons

 描述（由申请人提供）：本提案的总体目标是将两种新技术联合收割机结合起来，以提高胰岛移植治疗1型糖尿病的能力。第一项技术涉及以复合胰岛-肾（IK）的形式移植血管化胰岛，如我们最近所证明的，该技术能够治愈猪和狒狒模型中的糖尿病和肾衰竭。在该方案中，首先将部分胰腺切除术后获得的胰岛移植到自体肾包膜下以允许再血管化，然后将复合胰岛-肾移植到糖尿病动物中。虽然复合自体IK技术大大降低了由于免疫事件引起的移植物损伤程度，但由于缺氧和缺血性损失，IK复合物中仍然存在相当大的胰岛损失，最终需要对活体供体进行70%的胰腺切除术。为了提高IK复合存活率并显着减少供体胰岛的数量，我们建议使用第二种技术，该技术利用治疗诊断磁性纳米颗粒作为siRNA的载体，其在胰岛细胞中积累后可以在IK创建之前沉默负责胰岛损伤的基因。除了作为siRNA载体外，这些治疗诊断纳米颗粒还可以用作体内磁共振成像（MRI）报告者，纵向和非侵入性地提供有关移植物体积的信息。我们以前已经证明了这种技术在小鼠移植模型中提高移植物存活率的适用性。在本申请中，我们提出在非人灵长类动物中通过在产生IK复合物之前递送靶向与胰岛细胞凋亡有关的基因的siRNA纳米颗粒探针来研究这种方法的临床前效用。具体而言，我们将靶向caspase 3，caspase 8和Fas，单独或组合，作为最重要的介导细胞凋亡。体内MR成像将用于监测自体IK移植物体积，然后对受体糖尿病动物中的IK移植物进行连续成像，因为磁性纳米颗粒长期保留在胰岛中。我们期望通过靶向凋亡基因，我们将减少对自体IK复合物中胰岛的损伤，因此将减少IK复合物纠正糖尿病受体中高血糖症所需的供体胰岛的数量。通过MN-siRNA技术进一步减少胰腺切除量和无创评估胰岛体积，该程序的临床适用性将更有利于活体供体IK移植。

 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.