Cellular and Physical Function Outcomes Leading to Failed Muscle Recovery After Critical Illness

项目摘要 败血症和急性呼吸衰竭等危重疾病的生存伴随着严重的 身体并发症，许多患者获得长期损伤。机制和因素， 阻碍住院后肌肉大小和功能的恢复尚不清楚。目前还不清楚是否 严重疾病后的恢复导致随后的制造新蛋白质（蛋白质）能力的缺陷 合成）或如果分解代谢/炎症环境持续阻止肌肉再生， 肌干细胞（卫星细胞）融合成肌纤维。我们将通过研究骨骼， 肌肉蛋白质稳态、细胞环境、RNA和线粒体生物合成 身体功能结果密切相关。了解患者出院后的细胞环境 释放，以及它如何影响肌肉蛋白质周转将直接努力有效的治疗，以加速 肌肉再生该应用程序的总体目标是识别肌肉的细胞特性， 导致重症幸存者长期身体残疾。总的来说，我假设 肌肉中的细胞过程是危重病患者长期功能损伤的基础。在 目的1，我们将确定肌肉和身体功能恢复的纵向轨迹， 危重病患者肌肉形态学和细胞学特征。我们假设病人 ICU中病情严重程度较高且机械通气持续时间较长的患者， 恢复期持续性肌肉无力和肌肉力量不足。在目标2中，我们将识别细胞 导致严重疾病后肌肉功能障碍的机制。我们假设， 与对照组相比，持续的肌无力和疲劳损害了线粒体功能。此外，委员会认为， 我们假设重症患者的肌原纤维蛋白合成和核糖体水平升高， 在早期恢复中，肌肉再生是生物发生的，但由于蛋白水解的升高，肌肉再生不会发生。总体 该提案的目标集中在阐明导致恢复中肌肉质量失调的因素， 告知为什么有些患者会出现持续性残疾，而另一些患者会逐渐改善。建议的指导 团队提供知识和培训，以发展成为一名独立的临床研究者， 和应用科学目标1中的拟议培训计划强调临床试验方法和复杂的 纵向分析。对于目标2，培训重点是骨骼肌实验;具体来说，知识 评估肌肉蛋白质稳态、线粒体含量和功能以及肌肉形态。我会学习 技术技能，检查骨骼肌，包括稳定同位素标记，免疫组织化学，西方 印迹分析和显微镜检查。此外，拟议的研究和培训计划提供了 提供必要的培训和指导，将本建议书中的结论转化为有针对性的 在未来的R 01研究中进行康复和药物干预。

Project Summary Survival of critical illness such as sepsis and acute respiratory failure is accompanied by serious physical complications with many patients acquiring long-term impairments. Mechanisms and factors that impede the recovery of muscle size and function after hospitalization are not understood. It is unclear if recovery after critical illness leads to a subsequent deficiency in the ability to make new proteins (protein synthesis) or if a catabolic/inflammatory environment persists preventing muscle regrowth which involves muscle stem cell (satellite cell) fusion to myofibers. We will address gaps in knowledge by studying skeletal muscle proteostasis, cellular environment, and RNA and mitochondrial biogenesis after critical illness with closely aligned physical function outcomes. Understanding the cellular environment in the period after hospital release, and how it impacts muscle protein turnover will direct efforts to effective therapies to accelerate muscle regrowth. The overall goal of this application is to identify cellular properties of muscle that may contribute to long-term physical disability in survivors of critical illness. Overall, I hypothesize that aberrant cellular processes in muscle are underlying prolonged functional impairments in patients after critical illness. In Aim 1, we will determine the longitudinal trajectory of muscle and physical function recovery and establish muscle morphological and cellular characteristics in patients after critical illness. We hypothesize that patients with higher severity of illness in the ICU and with longer duration of mechanical ventilation will have the most persistent muscle weakness and deficits in muscle power in recovery. In Aim 2, we will identify cellular mechanisms that contribute to muscle dysfunction after critical illness. We hypothesize that patients with persistent muscle weakness and fatigue have impaired mitochondrial function compared to controls. Moreover, we hypothesize that survivors of critical illness have elevated myofibrillar protein synthesis and ribosome biogenesis in early recovery, but muscle regrowth does not occur due to elevated proteolysis. The overarching goal of this proposal focuses on elucidating the factors that lead to muscle mass dysregulation in recovery and inform why some patients develop persistent disability and others gradually improve. The proposed mentoring team provides the knowledge and training to develop into an independent clinical investigator integrating basic and applied science. The proposed training plan in Aim 1 emphasizes clinical trial methodologies and complex longitudinal analyses. For aim 2, the training focuses on skeletal muscle experiments; specifically, knowledge to assess muscle proteostasis, mitochondrial content and function, and muscle morphology. I will learn the technical skills to examine skeletal muscle including stable isotope labeling, immunohistochemistry, western blot analysis, and microscopy will be gained. Moreover, the proposed research and training plan provides the necessary training and mentorship to translate findings in this proposal into the development of targeted rehabilitation and pharmacological interventions in future R01 studies.