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

项目摘要 脓毒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，许多患者获得了长期的损害。机制和因素 住院后阻碍肌肉大小和功能恢复的原因尚不清楚。目前还不清楚是否 危重疾病后的康复导致随后产生新蛋白质(蛋白质)的能力不足 合成)，或者如果分解代谢/炎症环境持续存在，则阻止肌肉再生，这包括 肌肉干细胞(卫星细胞)与肌纤维融合。我们将通过研究骨骼来解决知识差距 危重疾病后的肌肉蛋白平衡、细胞环境以及RNA和线粒体生物发生 身体机能结果密切一致。对住院后细胞环境的认识 它的释放及其对肌肉蛋白质周转的影响将引导人们加速有效的治疗 肌肉再生。这个应用程序的总体目标是识别肌肉的细胞属性，这些属性可以 对危重疾病幸存者的长期身体残疾作出贡献。总体而言，我假设这一反常 肌肉中的细胞过程是危重疾病后患者长期功能损害的潜在原因。在……里面 目标1，我们将确定肌肉和身体功能恢复的纵向轨迹并建立 危重病患者的肌肉形态和细胞特征。我们假设病人 ICU中病情严重程度较高且机械通气时间较长的患者 持续的肌肉无力和恢复过程中的肌肉力量不足。在目标2中，我们将识别细胞 危重疾病后导致肌肉功能障碍的机制。我们假设患有这种疾病的患者 与对照组相比，持续性的肌肉无力和疲劳损害了线粒体的功能。此外， 我们假设危重病幸存者的肌原纤维蛋白合成和核糖体水平升高。 恢复早期的生物发生，但由于蛋白分解升高，肌肉不会再生。最重要的是 这项建议的目标集中在阐明导致恢复和恢复过程中肌肉质量失调的因素。 告知为什么一些患者会发展为持续性残疾，而另一些患者则逐渐好转。建议的辅导 团队提供知识和培训，以发展为集成基础设施的独立临床研究员 和应用科学。目标1中拟议的培训计划强调临床试验方法学和复杂性 纵向分析。对于目标2，培训的重点是骨骼肌实验；具体地说，知识 评估肌肉蛋白稳定性、线粒体含量和功能，以及肌肉形态。我会学到 检查骨骼肌的技术技能，包括稳定同位素标记、免疫组织化学、Western 印迹分析，得到显微镜下的结果。此外，拟议的研究和培训计划提供了 必要的培训和指导，以将本提案中的结果转化为有针对性的开发 未来R01研究中的康复和药理学干预。

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.