A Novel and Clinically Feasible Co-therapy of Deceased Donor Bone Marrow Combined With Donor-Matched Mesenchymal Stem Cells to Establish Immune Tolerance

一种新颖且临床可行的联合疗法，将已故供体骨髓与供体匹配的间充质干细胞相结合，以建立免疫耐受

基本信息

批准号：
10212956
负责人：
Brian H. Johnstone
金额：
$ 14.25万
依托单位：
OSSIUM HEALTH, INC.
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-08 至 2023-06-30
项目状态：
已结题

项目摘要

ABSTRACT Induction of immune tolerance with solid organ and vascular composite allografts is the Holy Grail for transplantation medicine. Induction of immune tolerance to mismatched grafts would obviate the need for life- long immunosuppression which is associated with serious adverse outcomes, such as renal failure, cancers and infections. Currently the most promising means of tolerance induction is through establishing a mixed chimeric state by transplantation of donor hematopoietic stem cells; however, with the exception of tolerogenic organs such as kidneys, the mixed chimerism approach has not achieved durable immune tolerance in preclinical or clinical trials with most solid organs or vascular composite allotransplants (VCA). Encouragingly, though, we have succeeded in achieving reduced immunosuppression in clinical trials of VCA using this approach. Mesenchymal stem (stromal) cells (MSC) are a potentially useful adjuvant to stem cell transplants (SCT) for promoting mixed chimerism as well as promoting complementary peripheral immunomodulatory functions. However, there are many unresolved issues to address before clinical translation of these promising therapeutic cells. A primary impediment is the source of MSC, which are rare in all tissues and require invasive procedures for procurement. Low abundance mandates extensive expansion in culture to generate sufficient numbers for human dosing. It has been observed in the clinical setting that the degree of expansion is negatively correlated with outcomes. Ossium Health has overcome this obstacle by identifying an abundant source of primary MSC associated with medullary bones of vertebral bodies obtained from deceased organ donors. These vertebral bone adherent MSC (vBA-MSC) are isolated by proteolytic digestion of bone fragments, following elution and cryopreservation of bone marrow (BM). Primary vBA-MSC are obtained at numbers that are 3 orders of magnitude higher than can be recovered from living donor iliac crest BM aspirates. A further advantage of vBA-MSC is they are matched to the donor, as opposed to third-party MSC, which enhances safety and potentially efficacy. Isolation and characterization of vBA-MSC from over 30 donors has demonstrated that the cells are no different than BM-MSC, but, because of their high numbers, unlike traditional BM-MSC, can be expanded to >5 billion cells with only 2 passages in culture. We hypothesize that donor-matched vBA-MSC will augment tolerance mechanisms of mixed chimerism with BM transplant as well as provide peripheral immunomodulatory functions to achieve durable tolerance for major histocompatibility complex mismatched solid organ and vascular composite tissue transplants. This hypothesis will be tested first in a murine orthotopic hind limb transplant VCA model and then in a murine heterotopic heart model. The hindlimb model studies will allow us to evaluate mechanisms of MSC immune tolerance due to the tolerogenic nature of BM-containing hind limbs. Durable grafts will be evaluated for T cell dynamics (especially memory T cells and regulatory T cells) and donor-specific immune tolerance with be confirmed with donor and third-party skin grafting. Information gained from this study will be used to perform similar studies in our heterotopic heart transplant model. If successful, the results of this study, combined with a plethora of MSC clinical trials as well as a long history of transplantation tolerance trials and our future Phase II studies to further define dosing parameters in small and large animal models, will provide compelling arguments to FDA for proceeding to clinical trials. Keywords: vascular composite allotransplantation; solid organ transplantation; immune tolerance; immunomodulation, regulatory T lymphocytes

抽象的固体器官和血管复合同种异体移植物诱导免疫耐受性是圣杯移植医学。诱导对不匹配的移植物的免疫耐受性将消除对生命的需求 - 长期的免疫抑制与严重的不良后果有关，例如肾衰竭，癌症和感染。目前，最有希望的耐受性吸引手段是建立混合通过移植供体造血干细胞的嵌合状态；但是，除了耐受性诸如肾脏等器官，混合的嵌合法尚未实现耐用的免疫耐受性大多数固体器官或血管复合同种异体移植（VCA）的临床前或临床试验。令人鼓舞的是，不过，我们成功地在VCA的临床试验中成功地实现了免疫抑制方法。间充质茎（基质）细胞（MSC）是对干细胞移植（SCT）的潜在有用的佐剂促进混合的嵌合体以及促进互补的外周免疫调节功能。但是，在这些有前途的临床翻译之前，有许多未解决的问题需要解决治疗细胞。主要障碍是MSC的来源，该障碍在所有组织中很少见，需要侵入性采购程序。低丰度要求在文化中广泛扩张以产生足够的人类剂量的数字。在临床环境中已经观察到扩张程度为与结果负相关。 Ossium Health通过确定与之相关的大量主要MSC来克服了这一障碍从已故的器官供体获得的椎体的髓质骨骼。这些椎骨粘附通过洗脱和冷冻保存，MSC（VBA-MSC）通过骨碎片的蛋白水解消化分离骨髓（BM）。初级VBA-MSC以比3个数量级的数字高于可以从活着的捐助者iLiac Crest BM抽吸物中回收。 VBA-MSC的另一个优势是它们是与捐赠者相匹配，而不是第三方MSC，这提高了安全性和潜在功效。隔离与30多个捐助者的VBA-MSC的表征表明，这些细胞没有什么不同 BM-MSC，但由于其数量很高，与传统的BM-MSC不同，可以扩展到50亿个单元文化中只有2段。我们假设供体匹配的VBA-MSC将增加混合嵌合的耐受性机制 BM移植以及提供外周免疫调节功能，以实现耐用的公差主要的组织相容性复合物不匹配固体器官和血管复合组织移植。这假设将首先在鼠的原位后肢移植VCA模型中进行检验，然后在鼠中进行测试。异位心脏模型。后肢模型研究将使我们能够评估MSC免疫的机制由于含BM的后肢的公差性质而引起的耐受性。将评估T细胞的耐用移植物动力学（尤其是记忆T细胞和调节性T细胞）和供体特异性免疫耐受性用捐赠者和第三方皮肤嫁接确认。从这项研究中获得的信息将用于执行在我们的异位心脏移植模型中的类似研究。如果成功，这项研究的结果与大量MSC临床试验以及悠久的历史相结合移植耐受试验和我们未来的II期研究，以进一步定义小剂量参数大型动物模型将为FDA提供引人入胜的论点，以进行临床试验。关键词：血管复合同倍植物；固体器官移植；免疫耐受性；免疫调节，调节性T淋巴细胞