Studies in pig-to-primate cardiac xenotransplantation

描述（由申请人提供）： 本申请的目的是使用基因工程供体、临床免疫抑制（IS）和诊断和治疗迟发性异种移植排斥（DXR）的方式，在猪-灵长类动物模型中实现生命支持心脏异种移植（CXTx）的90天中位生存期，从而开展CXTx的临床前研究。异种移植物的长期存活现在受到非Gal抗体介导的DXR（NGDXR）的限制。随着原位移植（OCXTx）结局的改善，已经出现了高达50%的病例早期异种移植功能受损。我们称之为围手术期心脏异种移植功能障碍（PCXD）。对于CXTx未来潜在的临床应用，了解NGDXR和PCXD的机制并改善其结果至关重要。特异性目的（SA）1-3的所有移植将使用GGTA-1糖基转移酶基因座失活的CD 55转基因供体（GTKO：CD 55+）。在SA 1中，为了更好地理解PCXD，在OCXTx之前，将使用血浆置换术去除预先形成的非Gal抗体（PNGA），并给予蛋白酶体抑制剂Bortez以去除浆细胞。这种治疗也将与cariporide心脏保护相结合，以减轻术前损伤。将通过超声心动图（ECHO）测量心脏功能、心脏损伤的生化标志物、受体抗体和浆细胞水平来评估PNGA耗竭和卡立泊来治疗对PCXD的影响，并将其与中期活检和心脏移植中的心脏基因表达相关。在SA 2中，为了预防基于B细胞和T细胞诱导治疗的DXR最佳IS，将使用三联药物IS和硼替佐米来控制SA 1存活的OCXTx受体中的NGA。我们将通过分析对GTKO PAEC的抗体应答以及我们已经鉴定的新型个体非Gal碳水化合物和蛋白质靶抗原来进一步研究NGDXR的机制。心脏基因表达的变化将与DXR相关。在SA 3中，我们利用了维持生命的胸腔内异位CXTx，这是一种目前临床上使用的心脏移植变体，它不仅是CXTx初始临床应用的潜在技术，将唯一允许a）通过ECHO观察PCXD的回收率，和B）开发DXR的诊断和治疗方法，而不会损失受体，因为天然心脏在这些期间支持循环。异种移植物功能障碍在这个目标中，血浆置换和硼替佐米将用于治疗DXR。本申请的目的是实现循环承载CXTx的3个月中位生存期，如果成功，将为在此资助期间的临床前研究奠定基础，以支持CXTx的临床应用。 相关性：成功的异种移植为缓解供移植器官和细胞的长期和日益短缺提供了潜在的临床解决方案。我们过去12年的研究已经实现了异位心脏异种移植的最长中位生存期和维持生命的原位心脏异种移植的最长生存期。该提案具体目标的实现将使异种心脏移植进入临床应用的门槛。

DESCRIPTION (provided by applicant): The objective of this application is to achieve 90-day median survival of life-supporting cardiac xenotransplantation (CXTx) in the pig-to-primate model using genetically-engineered donors, clinical immunosuppression (IS) and modalities to diagnose and treat delayed xenograft rejection (DXR) leading to preclinical studies of CXTx. Prolonged xenograft survival is now limited by non-Gal antibody-mediated DXR (NGDXR). With improved outcomes for orthotopic (OCXTx), it has emerged that early xenograft function is compromised in up to 50% of cases. We have termed this perioperative cardiac xenograft dysfunction (PCXD). For potential future clinical application of CXTx, it is essential to understand the mechanisms and improve the outcomes of both NGDXR and PCXD. All transplants for Specific Aims (SA) 1-3 will use donors transgenic for CD55 with inactivation of the GGTA-1 glycosyltransferase locus (GTKO:CD55+). In SA 1, to better understand PCXD, plasmapheresis will be used to remove preformed non-Gal antibody (PNGA) and the proteasome inhibitor Bortezomib given to delete plasma cells prior to OCXTx. This therapy will also be combined with cariporide cardiac preservation to mitigate preoperative injury. The impact of PNGA depletion and cariporide treatment on PCXD will be assessed by measurement of cardiac function by echocardiography (ECHO), biochemical markers of cardiac injury, recipient antibody and plasma cell levels, and will be correlated with cardiac gene expression in interim biopsies and explanted hearts. In SA 2, to prevent DXR optimal IS based on induction therapy for B- and T-cells, triple drug IS and Bortezomib will be used to control NGA in OCXTx recipients surviving SA 1. We will further study the mechanism(s) of NGDXR through analysis of antibody responses to GTKO PAECs and novel individual non-Gal carbohydrate and protein target antigens we have identified. Changes in cardiac gene expression will be correlated with DXR. In SA 3, we utilize life-supporting intrathoracic heterotopic CXTx, a currently clinically used heart transplant variant which, as well as being a potential technique for initial clinical application of CXTx, will uniquely allow a) observation of recovery of PCXD by ECHO and b) development of methods for the diagnosis and treatment of DXR without loss of the recipient as the native heart supports the circulation during these periods of xenograft dysfunction. In this aim, plasmapheresis and Bortezomib will be used to treat DXR. The objective of this application, to achieve 3-month median survival of circulation-bearing CXTx, if successful, will lay the groundwork for preclinical studies during this grant period to support clinical application of CXTx. RELEVANCE: Successful xenotransplantation offers a potential clinical solution to alleviate the chronic and increasing shortage of donor organs and cells for transplantation. Our previous studies over 12 years have achieved the longest median survival of heterotopic cardiac xenotransplants and the longest survivors of life-supporting orthotopic cardiac xenotransplants. Achievement of the specific aims of this proposal will bring cardiac xenotransplantation to the threshold of clinical application.