Preclinical evaluation of efficacy and safety of a new iron chelator therapy in chronic spinal cord injury

颈脊髓损伤（C-SCI）是一种常见的和经常毁灭性的战场损伤，可导致 在广泛的终身运动和痉挛残疾。随着早期疏散的进展， 积极的药物治疗，仍然没有有效的治疗方法，挽救脊髓（SC）神经元 /减少渐进式二次伤害。加速/减速和挫伤SCI导致微血管 剪切损伤、血脊髓屏障（BSCB）功能障碍和出血。扩散沉积铁 微出血通过活性氧（ROS）刺激氧化应激和炎症， 进一步诱发进行性残疾。迫切需要解决具体的残疾和风险问题 长期进行性残疾的因素，并开发具有良好潜力的有效疗法 翻译。该提案将测试一种新铁的安全性和有效性的临床前评估 螯合剂，SP 420，有或没有程序化的运动疗法在挫伤CSCI的啮齿动物模型中。 两种互补疗法的结合旨在增强显著降低 改善慢性SCI患者功能。这种新颖的专利铁螯合剂将消除出血引起的 游离的有毒铁，氧化应激/炎症的强大催化剂，并与运动疗法，它将 上调神经和血管营养剂以保护和治愈受损的神经和血管组织。的 这些研究的长期目标是开发有效的SCI治疗方法，并获得足够的临床前 支持美国食品药品监督管理局（FDA）研究性新药（IND）申请的证据， 人体脊髓损伤临床试验因此，将在临床相关啮齿动物中检测三种特定目的 C-SCI模型目前，该药物有一个用于铁储存疾病（例如地中海贫血）的IND。我们有 报告了该模型中持续的运动（痉挛和步态）残疾。具体目标1（SA-1）：安全性， 疗效和治疗持续时间的优化。SP 420将以一个固定剂量（80 mg/kg;代表人II期剂量），并针对生理盐水进行测试 安慰剂对照。治疗将在两个损伤后慢性时间点（损伤后第4周和第12周）开始。 第-12周），每一组使用单独的动物群。痉挛、步态、 和下行运动通路功能的轴突传导的完整性是主要的 结果沿着临床相关T1/T2 W、SWI/QSM和DTI MRI。全面的安全清单 治疗期间也将评估结果。具体目标2：确定 联合SP 420和运动疗法缓解痉挛和步态残疾。所有成果 将采用SA-1中所述的措施。将比较功能/成像/安全性结局 在三个治疗持续时间和两个损伤后时期中。具体目标3（SA-3）：确定 SCI和治疗对铁毒性/炎症、细胞损伤、BSCB的时间分布的影响 完整性和神经可塑性（营养因子）。铁沉积、组织 铁螯合剂的损伤和治疗效果将使用组织学、追踪和免疫组织化学相结合的方法进行研究。 示踪和免疫组织化学测定，以评估出血铁，氧化应激，炎症，标志物 BSCB的完整性，神经和血管保护因子。我们假设游离铁燃料 通过ROS的氧化应激和神经炎症，其驱动神经损伤的进展 和运动障碍。我们预测，拟议的SP-420疗法将逆转铁介导的 神经损伤和迟发性神经后遗症。两种互补的结合 治疗将增强显著改善SCI慢性环境中的功能所需的稳健性。 这些目标的实现将提供创新的、非侵入性的和以患者为中心的技术， 这将极大地促进退伍军人和平民SCI的治疗。

Cervical spinal cord injury (C-SCI) is a common and frequently devastating battlefield injury that can result in a broad range of life-long locomotor and spasticity disabilities. With advances in early evacuation and aggressive medical therapy, there are still no effective therapeutics that salvage spinal cord (SC) neurons /reduce progressive secondary damage. Acceleration/deceleration and contusion SCI cause micro-vessel shear injury, blood spinal cord barrier (BSCB) dysfunction, and hemorrhage. Iron deposited by diffuse micro-hemorrhage fuels oxidative stress and inflammation through reactive oxygen species (ROS), which further induce progressive disabilities. There is an urgent need to address both specific disabilities and risk factors for long-term progressive disabilities, and to develop effective therapies that have excellent potential for translation. The proposal will test the preclinical evaluation of the safety and efficacy of a new iron chelator, SP420, with or without a programmed locomotor therapy in a rodent model of contusion CSCI. The combination of two complementary therapies is aimed to amplify robustness necessary to significantly improve function in a chronic setting of SCI. This novel patented iron chelator will remove bleed-induced free toxic iron, a powerful catalyst of oxidative stress/inflammation, and with locomotor therapy it will upregulate neural and vascular trophic agents to protect and heal injured neural and vascular tissues. The long-term goal of these studies is to develop an effective SCI therapeutic, and to obtain sufficient preclinical evidence to support a Food and Drug Administration (FDA) Investigational New Drug (IND) application for human SCI clinical trials. Accordingly, Three Specific Aims will be tested in a clinically relevant rodent model of C-SCI. Currently, the drug has an IND for iron storage disease (e.g. Thalassemia). We have reported enduring motor (spasticity and gait) disabilities in this model. Specific Aim 1 (SA-1): Safety, efficacy and optimization of treatment duration. SP420 will be administered SQ at one fixed dose (80 mg/kg; represents the human phase II dose) in three different durations and tested against saline placebo controls. Treatment will be initiated at two post-injury chronic time points (post-injury week-4 and week-12), each using a separate cohort of animals. Quantitative physiological measures of spasticity, gait, and the integrity of axonal conduction of descending locomotor pathways functions are the primary outcomes along with clinically relevant T1/T2W, SWI/QSM, and DTI MRIs. A comprehensive list of safety outcomes will be assessed as well during the treatment. Specific Aim 2: To determine the efficacy of combined SP420 and locomotor exercise therapy in mitigating spasticity and gait disabilities. All outcome measures as stated in SA-1 will be applied. The functional/imaging/safety outcomes will be compared among the three treatment durations and two post-injury periods. Specific Aim 3 (SA-3): To determine SCI and treatment impacts on the temporal profile of iron toxicity/inflammation, cellular damage, BSCB integrity, and neuroplasticity (trophic factors). A cause-effect relationship between iron deposition, tissue damage and treatment effects of iron chelator will be studied using a combination of histological, track tracing, and immunohistochemical assays to evaluate bleed iron, oxidative stress, inflammation, markers for BSCB integrity, and neural, and vascular protective factors. We hypothesize that free bleed iron fuels oxidative stress and neuroinflammation through ROS which drives the progression of neurological damage and motor disabilities, in part. We predict that the proposed SP-420 therapy will reverse the iron-mediated neurological damage and delayed neurological sequelae. The combination of two complementary therapies will amplify robustness necessary to significantly improve function in a chronic setting of SCI. Achievement of these goals will provide innovative, non-invasive, and patient-centered technologies and treatments that will greatly facilitate treatment of veterans and civilian SCI.