Restoring Hematopoiesis Following Radiation Injury

放射损伤后恢复造血功能

• 批准号: 7020815
• 负责人: Amelia M. Bartholomew
• 金额: $ 50万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-10 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7020815
• 关键词: Primates; bioengineering /biomedical engineering; cell cell interaction; cell differentiation; cryopreservation; disease /disorder model; disease /disorder prevention /control; disease /therapy duration; graft versus host disease; hematopoiesis; hematopoietic stem cells; homologous transplantation; immune response; laboratory mouse; mesenchyme; nonhuman therapy evaluation; radiation hazard; stem cell transplantation; tissue engineering

Following acute radiation exposure, in addition to traumatic injuries such as fractures, lacerations, and burns, radiation syndromes involving the central nervous, gastrointestinal, cutaneous, and hematopoietic systems can ensue. Of the these syndromes, treatment has been identified for the hematopoietic syndrome (exposure of 0.7-10 Gy), in which the attendant morbidities of anemia, thrombbcytopenia, and the infectious complications associated with neutropenia, can be treated with both colony-stimulating factors, aggressive use of anti-microbials, and stem cell transplantation. The strategy involving allogeneic stem cell transplantation, due to the morbidity and mortality associated with graft versus host disease (GVHD) and graft failure, could be beneficial for individuals exposed to 4-10 Gy by hastening immunologic and hematologic reconstitution, however due to the risks of treatment, this application has been limited. Recently co-transplantation of the intact bone marrow microenvironment as bone fragments along with allogeneic stem cells has led to rapid engraftment and reduction in GVHD. Since mesenchymal stem cells (MSC) can be induced to differentiate into the in vivo components of the bone marrow microenvironment, it is likely that these cells could function similarly to the transplanted bone fragments. In murine experiments, we have observed MSC to rescue lethally irradiated hosts that had received sub-optimal numbers of stem cells, permit the reduction of host conditioning while establishing equal or better levels of engraftment than the combination of intensive host conditioning and untreated HSC grafts, enable stable xenogeneic enraftment (rat?> mouse) and reduce GVHD seven fold. In this proposal, we will test three main feasibility issues for the widespread use of an MSC product following a radiation incident: timing and physiological effectiveness of the engineered stem cell graft, prevention of GVHD, and the use of unrelated ex vivo expanded cryopreserved MSC in a pre-clinical primate model. First, in a lethal irradiation model, we will test whether MSC engineered hematopoietic grafts can be administered in a delayed fashion with similar efficacy, to those administered on day 0. In sub-lethally irradiated mice, we will test whether MSC alone without hematopoietic stem cells can hasten hematopoietic recovery and thereby improve immune reconstitution. To test the effect of MSC on immune function recovery, recipients will be challenged with a Klebsiella inoculum. Second, we will test whether suppression of GVHD is due to the generation of regulatory cells or the direct effect of MSC on donor T cells. Last, using the preclinical cynomolgus monkey model of allogeneic stem cell transplantation, we will test whether exposure to 600cGy of irradiation can be successfully treated with MSC-engineered stem cell grafts. To simulate conditions that might mimic MSC availability clinically, we will test whether the use of either donor or 3rd party cryopreserved MSC can aid allogeneic hematopoietic engraftment, since our murine data indicate that the effect of MSC on engraftment can occur with an MSC source unrelated to the donor. The use of 3rd party ex vivo expanded cryopreserved MSC is clinically attractive, since it potentially reduces the time to obtain MSC while increasing widespread availability for clinical use.

急性辐射暴露后，除了骨折、撕裂伤和烧伤等创伤性损伤外，还可能发生涉及中枢神经、胃肠道、皮肤和造血系统的辐射综合征。在这些综合征中，已经确定了对造血综合征的治疗（0.7-10戈伊的照射），其中伴随的 贫血、血小板减少症和与中性粒细胞减少症相关的感染并发症的发病率可以用集落刺激因子、积极使用抗微生物剂和干细胞移植来治疗。由于与移植物抗宿主病（GVHD）和移植物衰竭相关的发病率和死亡率，涉及同种异体干细胞移植的策略可通过加速免疫和血液重建而有益于暴露于4-10戈伊的个体，然而由于治疗的风险，该应用受到限制。最近，将完整的骨髓微环境作为骨碎片沿着与同种异体干细胞共移植，导致了快速植入和GVHD的减少。由于间充质干细胞（MSC）可以被诱导分化为骨髓微环境的体内成分，因此这些细胞可能与移植的骨碎片具有相似的功能。在小鼠实验中，我们观察到MSC拯救接受了次优数量干细胞的致死性照射宿主，允许减少宿主调节，同时建立与强化宿主调节和未处理HSC移植物的组合相等或更好的植入水平，能够实现稳定的异种植入（大鼠？小鼠）并将GVHD降低七倍。在本提案中，我们将测试辐射事件后广泛使用MSC产品的三个主要可行性问题： 干细胞移植、GVHD的预防以及在临床前灵长类动物模型中使用无关的离体扩增的冷冻保存的MSC。首先，在致死辐射模型中，我们将测试MSC工程化的造血移植物是否可以以与第0天施用的那些类似的功效以延迟方式施用。在亚致死剂量照射的小鼠中，我们将测试MSC是否 没有造血干细胞的情况下单独使用可以加速造血恢复，从而改善免疫重建。为了测试MSC对免疫功能恢复的影响，将用克雷伯氏菌接种物攻击受体。其次，我们将测试GVHD的抑制是否是由于调节细胞的产生或MSC对供体T细胞的直接作用。最后，使用异基因干细胞移植的临床前食蟹猴模型，我们将测试暴露于600 cGy的辐射是否可以用MSC工程干细胞移植物成功治疗。为了模拟临床上可能模拟MSC可用性的条件，我们将测试使用供体或第三方冷冻保存的MSC是否可以帮助同种异体造血移植，因为我们的小鼠数据表明MSC对移植的影响可以发生在与供体无关的MSC来源中。使用第三方离体扩增的冷冻保存的MSC在临床上是有吸引力的，因为它潜在地减少了获得MSC的时间，同时增加了临床使用的广泛可用性。