Preclinical Therapy and Novel Mechanisms in Ventilator-induced Diaphragm Atrophy

呼吸机引起的膈肌萎缩的临床前治疗和新机制

• 批准号: 8541548
• 负责人: JOSEPH B SHRAGER
• 金额: --
• 依托单位: VETERANS ADMIN PALO ALTO HEALTH CARE SYS
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8541548
• 关键词: Animals; Antioxidants; Apoptosis; Atrophic; Autophagocytosis; Bioinformatics; Biological Assay; Biomedical Engineering; Breathing; Cessation of life; Chimeric Proteins; Clinic; Clinical; Clinical Trials; Critical Illness; Development; Devices; Effectiveness; Electric Stimulation; Elements; Engineering; Event; Evolution; Experimental Models; Fiber; Functional disorder; Future; Genetic; Goals; Health Care Costs; Hour; Human; In Vitro; Industry; Intensive Care Units; Lead; Limb structure; Measures; Mechanical Ventilators; Mechanical ventilation; Mediating; Methods; MicroRNAs; Mitochondria; Modeling; Molecular; Morbidity - disease rate; Mus; Muscle; Muscle Development; Muscular Atrophy; Neck; Oxidative Stress; Pathogenesis; Pathway interactions; Patients; Peptides; Pharmaceutical Preparations; Prevention; Process; Proteolysis; Rattus; Regulation; Reporting; Respiratory Diaphragm; Rodent; Role; Series; Small RNA; Structure of phrenic nerve; Superoxides; Testing; Therapeutic; Therapy Clinical Trials; Thioredoxin-2; Time; Transgenic Mice; Translating; United States; Ventilator; Veterans; Weaning; Work; base; effective therapy; genetic manipulation; in vivo; insight; mortality; mouse model; muscle form; nerve supply; novel; overexpression; pre-clinical; pre-clinical therapy; preclinical study; prevent; public health relevance; research study; scale up; therapeutic target; ubiquitin ligase; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): It has been clearly established in both clinical and experimental models that diaphragm disuse as a result of placement upon full mechanical ventilator support leads to early and severe diaphragm atrophy and dysfunction (VIDD - Ventilator-Induced Diaphragm Dysfunction). This diaphragm dysfunction appears to be an important cause of the difficulty often encountered weaning patients from mechanical ventilation (MV); it is thus the basis for subsequent ventilator-associated complications which result in increased morbidity, mortality and health care costs among the millions of patients requiring MV yearly. Several important mechanisms underlying VIDD have been elucidated in recent years, with mitochondrial oxidative stress emerging as a central effector of the process, but preclinical therapeutic trials based upon these mechanistic insights are only now beginning. The broad goals of this work are to: 1) Carry out preclinical trials to prevent VIDD in rodents using intermittent phrenic nerve stimulation and novel mitochondrial-targeted antioxidants (MTAs). 2) To further explore a novel mechanism of VIDD involving microRNA regulation of FOXOs, and to test the therapeutic potential of microRNAs. Phrenic nerve stimulation has never been evaluated in any model of VIDD, despite the fact that VIDD clearly results from diaphragm inactivity and that the phrenic nerve is anatomically accessible to stimulation in patients. We hope to establish proof-of-concept that phrenic stimulation will prevent VIDD, allowing subsequent scale-up to a workable clinical stimulation device. Regarding MTAs, a therapeutic benefit in VIDD has been suggested by only a single, perhaps flawed, study using a small mitochondria-targeted peptide. In order to confirm the mechanism of action of MTAs in this setting and provide an alternative MTA that may be more easily advanced to the clinic, we propose to attack mitochondrial oxidative stress and thus VIDD by both endogenous and exogenous approaches. Our endogenous approach will test for prevention of VIDD by MV experiments in mice that are engineered to overexpress the mitochondria-resident antioxidant thioredoxin-2 (Trx2). Our exogenous approach will include both the exogenous delivery of a TAT-Trx2 fusion protein and the delivery of the MTA drugs, SKQ1 and MitoQ. In this series of experiments, we will use our new model of mouse MV / VIDA - a model which will also allow future exploration of VIDD using additional genetic mouse models. Lastly, we will confirm our preliminary evidence that microRNAs, particularly microRNA-320a, effect VIDA by increasing muscle proteolysis via FOXO-mediated overexpression of the E3 ubiquitin ligases atrogin and MuRF1. We will subsequently test the therapeutic potential of systemic microRNA therapy against VIDA. As a whole, these experiments will both advance our understanding of the basic mechanisms underlying VIDA/VIDD and make substantial steps towards effective clinical therapies by testing these in animals.

描述（由申请人提供）： 在临床和实验模型中已经明确确定，由于在完全机械呼吸机支持下放置而导致的膈肌废用会导致早期和严重的膈肌萎缩和功能障碍（VIDD -呼吸机诱导的膈肌功能障碍）。这种横膈膜功能障碍似乎是使患者脱离机械通气（MV）时经常遇到困难的重要原因;因此，它是随后呼吸机相关并发症的基础，这些并发症导致每年数百万需要MV的患者的发病率、死亡率和医疗保健费用增加。近年来已经阐明了VIDD的几个重要机制，线粒体氧化应激作为该过程的中心效应物出现，但基于这些机制见解的临床前治疗试验现在才开始。这项工作的广泛目标是：1）进行临床前试验，以防止VIDD在啮齿动物使用间歇性膈神经刺激和新的神经靶向抗氧化剂（MTA）。2)进一步探索VIDD涉及microRNA调控FOXO的新机制，并测试microRNA的治疗潜力。膈神经刺激从未在任何VIDD模型中进行过评价，尽管VIDD明显是由膈肌不活动引起的，并且膈神经在解剖学上可接近患者的刺激。我们希望建立膈神经刺激可以预防VIDD的概念验证，从而允许随后扩大到可行的临床刺激器械。关于MTA，VIDD中的治疗益处仅由使用小的靶向肽的单一的、可能有缺陷的研究提出。为了证实MTA在这种情况下的作用机制，并提供一种更容易进入临床的替代MTA，我们建议通过内源性和外源性方法来攻击线粒体氧化应激，从而攻击VIDD。我们的内源性方法将通过MV实验在小鼠中测试对VIDD的预防，所述小鼠被工程化以过表达存在于大肠杆菌中的抗氧化剂硫氧还蛋白-2（Trx 2）。我们的外源性方法将包括TAT-Trx 2融合蛋白的外源性递送和MTA药物SKQ 1和MitoQ的递送。在这一系列实验中，我们将使用我们的小鼠MV /维达新模型-该模型也将允许未来使用其他遗传小鼠模型探索VIDD。最后，我们将证实我们的初步证据，即microRNA，特别是microRNA-320 a，通过FOXO介导的E3泛素连接酶atrogin和MuRF 1的过表达增加肌肉蛋白水解来影响维达。我们随后将测试针对维达的系统性microRNA疗法的治疗潜力。总的来说，这些实验将促进我们对维达/VIDD的基本机制的理解，并通过在动物中测试这些方法，朝着有效的临床治疗迈出实质性的一步。