Noninvasive two-photon imaging of pancreatic islet graft rejection in the eye

描述（由申请人提供）： 移植治疗1型糖尿病后胰岛细胞存活主要受免疫介导的 排斥反应因此，原位监测移植物排斥反应在真实的时间是至关重要的适当干预。目前的成像方式缺乏空间和时间分辨率，因此只有在发生宏观移植物损伤时才能检测到胰岛的免疫攻击。本申请的长期目标是建立一种高分辨率成像方法，其中可以无创地监测和原位研究活体受体中移植组织的免疫介导的排斥反应。本研究旨在建立小鼠眼前房胰岛移植模型，作为同种异体胰岛移植免疫排斥反应的双光子荧光成像模型。眼睛的前房提供了一个自然的身体窗口，允许无创监测非常相同的胰岛纵向。该假说认为，尽管免疫豁免，但胰岛同种异体移植物的免疫介导的眼内排斥反应仍会发生，并且可以很容易地在真实的时间内进行无创成像。这是第一次，该项目将使研究体内早期排斥反应在真实的时间。这将使胰岛移植排斥反应中细胞运动和动力学的研究成为可能。申请人提供的初步数据显示了同种异体胰岛的排斥反应，并证明了眼内胰岛功能和排斥反应成像的强度和可行性。这些数据首次显示了单个免疫细胞在体内向移植部位的募集和胰岛移植物的主动浸润。申请人提出以下具体目的：（1）建立眼内移植作为移植胰岛的排斥模型。目前的假设是胰岛排斥是由早期和晚期细胞介导的， 持续性炎症，并最终通过效应T淋巴细胞;（2）确定胰岛同种异体移植物眼内排斥反应的细胞机制。工作假设是，排斥反应过程需要胰岛移植物中炎性细胞与同种异体效应T细胞的密切联系。据预测，胰岛细胞死亡发生在这些细胞复合体附近。这些研究将揭示胰岛同种异体移植免疫介导的眼内排斥反应的动力学和动力学，并将提供一个平台来测试和改进旨在提高胰岛存活率和移植物长期接受性的新的和现有的治疗方案。能够在真实的时间内监测胰岛移植物的命运将使早期干预成为可能，并将解决胰岛移植作为治疗1型糖尿病的一种疗法的主要限制。该项目允许早期发现和研究排斥反应，从而更好地了解该过程，并能够及时干预，以提高胰岛细胞存活率和长期移植物接受率。

DESCRIPTION (provided by applicant): Islet cell survival after transplantation to cure type 1 diabetes is limited primarily by immune-mediated rejection. Therefore, in situ monitoring of graft rejection in real time is critical for proper intervention. Current imaging modalities lack spatial and temporal resolution and consequently immune attack of the islets is only be detected once macroscopic graft damage has occurred. The long-term goal of this application is to establish a high resolution imaging approach where immune-mediated rejection of graft tissue in live recipients can be monitored noninvasively and studied in situ. This project aims to establish pancreatic islet transplantation into the murine anterior chamber of the eye as a model for two-photon fluorescence imaging of immune rejection of transplanted allogeneic islets. The anterior chamber of the eye provides a natural body window that allows noninvasive monitoring of the very same islets longitudinally. The hypothesis is that immune-mediated intraocular rejection of islet allografts occurs despite immune privilege and can be readily imaged noninvasively in real time. For the first time, this project will enable studying in vivo early rejection in real time. It will enable the study of cellular motility and dynamics during islet allograft rejection. Pilot data provided by the applicant revealed rejection of allogeneic islets and demonstrated the strength and feasibility of imaging intraocular islet function and rejection. These data showed for the first time in vivo recruitment of individual immune cells to the graft site and active infiltration of the islet grafts. The applicant proposes the following specific aims: (1) Establish intraocular transplantation as a rejection model for transplanted pancreatic islets. The working hypothesis is that islet rejection is mediated by early and persistent inflammation and ultimately by effector T lymphocytes; and (2) Identify the cellular mechanisms of intraocular rejection of islet allografts. The working hypothesis is that the rejection process requires the close association of inflammatory cells with allospecific effector T cells in the islet grafts. It is predicted that islet cell death occurs near these cell complexes. These studies will reveal the kinetics and dynamics of immunemediated intraocular rejection of islet allografts and will provide a platform to test and refine novel and existing therapeutic regimens aimed at enhancing islet survival and long-term acceptance of grafts. Being able to monitor the fate of islet grafts in real time would enable early intervention and will address the major limitation to pancreatic islet transplantation as a therapy to cure type 1 diabetes. This proposed project allows the early detection and study of rejection providing a better understanding of the process and the ability for a timely intervention to improve islet cell survival and long-term graft acceptance.