Locomotor Training with Anabolic Adjuvants for Musculoskeletal Recovery After SCI

肌肉和骨骼丢失是脊髓损伤(SCI)的显著后果，它会阻碍身体康复。 并使健康状况恶化。这种肌肉骨骼的衰退是由以下原因引起的 神经损伤，并被其他因素加剧，包括受损的胰岛素样生长因子-1 肌肉和骨骼中的信号。多因素损害的存在可能是相对的基础 大多数单独的药物和机械重新加载策略在再生双侧时无效 严重脊髓损伤后的骨骼和肌肉。我们的目标是建立一种多式联运战略，结合物理 应用IGF-1辅助康复以促进脊髓损伤后肌肉骨骼的恢复，从而解决 停用和合成代谢信号受损。我们的数据表明，被动自行车训练和体重 支持跑步机(TM)训练，这是一种基于活动的身体康复形式，可以减少肌肉损失和 促进中度挫伤脊髓损伤后啮齿动物的神经可塑性。然而，这些身体康复 在严重的脊髓损伤后，这些疗法在再生肌肉和骨骼方面相对无效。已知胰岛素样生长因子-1 独立地影响肌肉骨骼的完整性，这表明这种合成代谢可能代表着一种可行的 提高脊髓损伤后的体能康复水平。事实上，我们的数据表明，IGF-1在肌肉中的病毒过度表达 在停用时保护肌肉，并在重新加载时促进肌肉和骨骼的恢复。此外，病毒IGF- 1的表达被证明促进了脊髓横断后皮质脊髓运动神经元的存活，以及 对脊髓损伤后肌肉功能的保护至关重要。然而，病毒IGF-1疗法并不是很有效 翻译过来的。为了解决这个问题，我们开发了一种新型的口服生物利用型人IGF-1，在可食用中表达 植物(植物-Pro-IGF-1)，并优化了大鼠和小鼠的给药方案，通过以下方式增加循环IGF-1 300-500%，至少12小时，不抑制循环血糖。我们还证明了植物- 原胰岛素样生长因子-1到达骨骼肌，主要靶组织，植物原-胰岛素样生长因子-1磷酸化IGFR 和Akt以时间和剂量依赖的方式在培养细胞中，验证生物活性。对于这项提议，我们将 评价单独和联合以活动为基础的身体康复对我们的啮齿动物的植物-前IGF-1 严重挫伤脊髓损伤模型，这代表了将这种高度新颖的化合物转化为 在脊髓损伤人群中进行临床试验。所有研究都将在4个月大的雄性和雌性斯普拉格犬身上进行- 接受假手术的Dawley大鼠与严重的中胸(T9)挫伤脊髓。我们将进行实验 使用立即和延迟治疗策略来确定预防和再生效果， 这提供了对最合适的治疗窗口的洞察。我们亦会评估 被动(周期)负荷与动态(TM)负荷对IGF-1疗效的影响，我们将评估前肢和 后肢肌肉骨骼结果以确定治疗效果是否需要正常神经支配或 未受损的运动活动，只有在严重的T9脊髓损伤后才存在于前肢的因素。结果包括： 肌肉横截面积(通过MRI)，肌肉形态(通过免疫组织化学)，分离的肌肉 力学，肌肉IGF-1信号，骨体积(通过microCT)，骨转换(通过组织形态计量学和 循环标志物)、比目鱼肌皮质脊髓运动神经元的形态/分布以及血清IGF-1、IGF结合 蛋白质3和葡萄糖。这项提议有两个具体目标： 目的1.评价应用胰岛素样生长因子-1(IGF-1)增强急性心肌梗死患者肌肉骨骼效应的能力。 啮齿动物挫伤脊髓损伤模型中以活动为基础的物理康复。 目标2.确定将以活动为基础的身体康复与 在严重脊髓损伤后长期给予IGF-1佐剂可再生骨骼和肌肉。

Muscle and bone loss are hallmark consequences of spinal cord injury (SCI) that impede physical rehabilitation and worsen health outcomes. This musculoskeletal decline is precipitated by disuse resulting from the neurologic insult and is intensified by other factors, including impaired insulin-like growth factor (IGF)-1 signaling in muscle and bone. The presence of multifactorial impairments likely underlies the relative ineffectiveness of most stand-alone pharmacologic and mechanical reloading strategies in regenerating both bone and muscle after severe SCI. Our goal is to establish a multimodal strategy combining physical rehabilitation with adjuvant IGF-1 to promote musculoskeletal recovery after SCI, thus addressing both the disuse and the impaired anabolic signaling. Our data indicate that passive Cycle training and bodyweight supported treadmill (TM) training, forms of activity-based physical rehabilitation, reduce muscle loss and promote neuroplasticity in rodents after moderate contusion SCI. However, these physical rehabilitation regimens are relatively ineffective in regenerating muscle and bone after severe SCI. IGF-1 is known to independently influence musculoskeletal integrity, suggesting this anabolic may represent a viable candidate to improve physical rehabilitation after SCI. Indeed, our data indicate that viral overexpression of IGF-1 in muscle protects muscle during disuse and promotes muscle and bone recovery upon reloading. Additionally, viral IGF- 1 expression has been shown to promote corticospinal motor neuron survival after spinal cord transection, an effect essential to the preservation of muscle function after SCI. However, viral IGF-1 therapies are not highly translational. To address this, we developed a novel orally-bioavailable human IGF-1 expressed in edible plants (Plant-Pro-IGF-1) and optimized a dosing regimen in rats and mice that increases circulating IGF-1 by 300-500% for at least 12 h, without suppressing circulating glucose. We have also demonstrated that Plant- Pro-IGF-1 reaches skeletal muscle, the primary target tissue, and that Plant-Pro-IGF-1 phosphorylates IGFR and Akt in time and dose-dependent manners in cultured cells, validating bioactivity. For this proposal, we will evaluate Plant-Pro-IGF-1 alone and in combination with activity-based physical rehabilitation in our rodent severe contusion SCI model, which represents the next step in translating this highly novel compound to clinical trials in the SCI population. All studies will be conducted in 4-month old male and female Sprague- Dawley rats receiving Sham surgery vs severe mid-thoracic (T9) contusion SCI. We will perform experiments using immediate and delayed treatment strategies to determine preventative and regenerative efficacy, respectively, which provides insight into the most appropriate treatment window. We will also assess the influence of passive (Cycle) vs dynamic (TM) loading on IGF-1 efficacy and we will evaluate forelimb and hindlimb musculoskeletal outcomes to determine if therapeutic efficacy requires normal innervation or unimpaired locomotor activity, factors that are only present in forelimbs after severe T9 SCI. Outcomes include: muscle cross sectional area (via MRI), muscle morphology (via immunohistochemistry), isolated muscle mechanics, muscle IGF-1 signaling, bone volume (via microCT), bone turnover (via histomorphometry and circulating markers), soleus corticospinal motor neuron morphology/distribution, and serum IGF-1, IGF binding protein 3, and glucose. This proposal has two Specific Aims: Aim 1. Evaluate the ability of administered IGF-1 to enhance the acute musculoskeletal effects of activity-based physical rehabilitation in a rodent contusion SCI model. Aim 2. Determine if a multimodal therapy combining activity-based physical rehabilitation with adjuvant IGF-1 regenerates bone and muscle when administered chronically after severe SCI.