Evaluation of Hypoxia in Grafted Dopamine Neurons

描述(申请人提供)：移植细胞的低存活率限制了神经疾病的脑内神经移植策略。例如，在帕金森病动物模型和帕金森病S患者的临床试验中，移植的多巴胺(DA)神经元的存活率仅为5%-20%。临床成功的关键是开发方法，使移植的DA神经元的活性和宿主纹状体的再神经支配显着增加。R03的应用重点是利用一个公认的范例--中脑DA神经元移植，直接研究低氧在脑内移植中的作用。我们的研究表明，移植的中脑细胞在移植后的最初几天内发生大量的凋亡，然后急剧减少。移植的DA神经元死亡的时间进程与移植细胞的宿主血管形成的延迟密切相关。移植细胞在移植后立即经历的血液中缺乏氧气或缺氧，可能是引发细胞凋亡的一个可能因素。然而，缺氧在限制移植物存活中的作用从未被直接评估过。这一建议的总体假设是，在移植后早期，当移植细胞没有充分的血管形成时，移植的DA神经元的存活受到严重的缺氧限制。确认低氧是移植物存活的一个重要限制因素，将指导未来旨在加强脑内多种细胞类型(原代细胞、干细胞)移植以治疗广泛的神经疾病的策略。

DESCRIPTION (provided by applicant): Intracerebral neural grafting strategies for neurological disorders are limited by the poor survival rate of grafted cells. For example, the survival rate of dopamine (DA) neurons grafted in parkinsonian animal models and in clinical trials with Parkinson s patients is merely 5-20%. Critical to clinical success is the development of methods whereby grafted DA neuron viability and reinnervation of the host striatum are markedly increased. The focus of this R03 application is to directly examine the role of hypoxia in intracerebral grafts utilizing a well-established paradigm, grafts of mesencephalic DA neurons. Our research indicates that massive apoptosis of grafted mesencephalic cells occurs within the first few days after transplantation and then sharply diminishes. This time course of grafted DA neuron death closely parallels the delay in host vascularization of the grafted cells. The lack of blood-borne oxygen, or hypoxia, experienced by the grafted cells during the immediate post-grafting interval is a likely candidate to trigger apoptotic cell death. However, the role of hypoxia in limiting graft survival has never been directly assessed. The overall hypothesis of this proposal is that grafted DA neuron survival is severely limited by hypoxia during the early post-transplantation interval when grafted cells are not adequately vascularized. Identification of hypoxia as a significant constraint on graft survival would direct future strategies aimed at enhancing intracerebral grafts of numerous cell types (primary cells, stem cells) implanted to treat a wide range of neurological disorders.