Anti-CD47 mAb Therapy to Improve Kidney Transplantation

描述（申请人提供）：器官移植是现代医学的伟大成功故事之一。然而，合适的器官供应远远落后于需求，许多患者在等待器官时死亡。虽然最近在器官获取、保存和后续免疫抑制方面取得了许多进展，但缺血再灌注损伤（IRI）的预防仍然存在问题。IRI发生在缺血/缺氧器官与受体循环相连时。这种活性氧、炎症介质和促炎因子的风暴会损害新器官，并对受体造成严重破坏。目前的研究表明，增强eNOS和nNOS产生的有益的低水平一氧化氮（NO）可以显着改善IRI和移植结果。Vasculox的创始人发现了一种配体-受体系统，血小板反应蛋白-1（TSP 1）和CD 47，它持续对抗所有血管细胞中有益NO的作用。在小鼠中敲除CD 47或用单克隆抗体（mAb）阻断CD 47导致在许多手术缺血模型中增强的组织灌注和在肝脏和后肢IRI模型中的实质性保护。此外，我们在离体大鼠肝脏机器灌注系统中的初步研究支持抗CD 47疗法对IRI的功效。在这个第一阶段的建议，我们试图在一个良好的特点，在大鼠肾移植的体内模型进行概念研究的证据。在目标1中，我们将测试抗CD 47 mAb治疗供体肾在冷缺血期间保护其免受IRI的功效。初步研究表明，抗CD 47 mAb可在器官收获时在冷保存培养基冲洗液中给药。目的2将确定接受者的肠外抗CD 47 mAb治疗（除了供体肾脏的预处理之外）是否会进一步改善移植结局。在这两个目标中，将监测肾功能（尿生成、肌酐、BUN和可溶性酶释放）和细胞因子水平的读数。将测定肾脏中的环GMP水平和血浆亚硝酸盐水平，以确认该模型中抗CD 47 mAb的作用机制。本I期项目中获得的数据将为肾移植中抗CD 47 mAb治疗建立概念证据。 公共卫生相关性：Vasculox公司的创始人发现了一种调节受体CD 47，它抑制所有血管组织中的一氧化氮信号传导。一氧化氮在血管系统中提供许多有益的作用，包括限制缺血再灌注损伤。因此，阻断CD 47和防止一氧化氮抑制改善缺血-再灌注损伤，并有望作为改善预定用于移植的器官的状况和控制由缺血再灌注损伤引起的对受体的损害的手段。Vasculox正在开发一种针对CD 47的单克隆抗体，该项目旨在测试这种抗体在肾移植动物模型中的功效。这将为开发用于器官移植的人源化抗CD 47抗体提供关键的概念证明，从而改善所有移植受体的结果并扩大可用于移植的器官数量。

DESCRIPTION (provided by applicant): Organ transplantation is one of the great success stories of modern medicine. However, the supply of suitable organs lags far behind the need and many patients die while waitlisted for organs. While there have been many recent strides in organ procurement, preservation and follow-up immune suppression, prevention of ischemia-reperfusion injury (IRI) remains problematic. IRI occurs when the ischemic/hypoxic organ is connected to the recipient's circulation. This storm of reactive oxygen species, inflammatory mediators and prothombotic factors damages the new organ and wreaks havoc upon the recipient as well. Current work indicates that enhancing the beneficial, low levels of nitric oxide (NO) produced by eNOS and nNOS can dramatically improve IRI and transplant outcomes. The founders of Vasculox have discovered a ligand-receptor system, thrombospondin-1 (TSP1) and CD47, that continually opposes the action of beneficial NO in all vascular cells. Knocking out CD47 in mice or blocking CD47 with a monoclonal antibody (mAb) results in enhanced tissue perfusion in a number of surgical ischemia models and substantial protection in models of liver and hindlimb IRI. Further, our initial studies in an ex vivo rat liver machine perfusion system support the efficacy of anti- CD47 therapy for IRI. In this phase one proposal, we seek to perform proof of concept studies in a well-characterized in vivo model of rat kidney transplantation. In Aim 1, we will test the efficacy of anti-CD47 mAb treatment of the donor kidney during cold ischemia to protect it from IRI. Preliminary studies indicate that the anti-CD47 mAb can be administered in the cold preservation medium flush at organ harvest. Aim 2 will determine if parenteral anti-CD47 mAb treatment of the recipient (in addition to pretreatment of the donor kidney) will further improve transplant outcomes. In both aims, readouts of kidney function (urine production, creatinine, BUN and soluble enzyme release) and cytokine levels will be monitored. Cyclic GMP levels in kidneys and plasma nitrite levels will be determined to confirm the mechanism of anti-CD47 mAb action in this model. The data obtained in this phase I project will establish proof of concept for anti-CD47 mAb therapy in kidney transplantation. PUBLIC HEALTH RELEVANCE: The founders of Vasculox Inc, have discovered a regulatory receptor, CD47, that inhibits nitric oxide signaling in all vascular tissues. Nitric oxide provides many beneficial effects in the vascular system, including limiting ischemia-reperfusion injury. Therefore blocking CD47 and preventing nitric oxide inhibition improves ischemia-reperfusion injury and holds promise as a means to improve the condition of organs destined for transplant and to control the damage to the recipient caused by ischemia reperfusion injury. Vasculox is developing a monoclonal antibody that targets CD47 and in this project aims to test the efficacy of such an antibody in an animal model of kidney transplantation. This will provide critical proof of concept for development of a humanized anti-CD47 antibody for use in organ transplantation thereby improving the outcome for all transplant recipients and expanding the number of organs available for transplantation.