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: 8803357
• 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/8803357
• 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; 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; Therapeutic 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; 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)： 临床和实验模型都清楚地表明，由于放置在全机械呼吸机支架上而停用的横隔膜会导致早期严重的横隔膜萎缩和功能障碍(VIDD-呼吸机引起的横隔膜功能障碍)。这种横隔膜功能障碍似乎是撤机患者经常遇到困难的一个重要原因；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需要机械通气的数百万患者的发病率、死亡率和医疗费用增加。近年来，VIDD的几个重要机制已被阐明，线粒体氧化应激成为这一过程的中心效应者，但基于这些机制的临床前治疗试验才刚刚开始。这项工作的主要目标是：1)开展临床前试验，使用间歇性膈神经刺激和新型线粒体靶向抗氧化剂(MTA)预防啮齿类动物的VIDD。2)进一步探讨MicroRNA调控FOXO的VIDD新机制，并检测microRNA的治疗潜力。在任何VIDD模型中，从未评估过膈神经刺激，尽管VIDD明显是由于横隔膜不活动造成的，而且患者在解剖上可以接受刺激。我们希望建立概念验证，即膈刺激将预防VIDD，使随后的规模扩大到可行的临床刺激设备。关于MTA，只有一项单一的、可能有缺陷的研究表明，使用一种小的线粒体靶向多肽，对VIDD有治疗益处。为了确定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两种方法来攻击线粒体氧化应激，从而对抗VIDD。我们的内源性方法将通过在小鼠身上进行MV实验来测试预防VIDD的能力，这些实验被设计为过表达线粒体驻留的抗氧化剂硫氧还蛋白-2(Trx2)。我们的外源方法将包括外源传递TAT-Trx2融合蛋白和传递MTA药物SKQ1和MitoQ。在这一系列实验中，我们将使用我们的新的小鼠MV/VIDA模型-该模型也将允许未来使用额外的遗传小鼠模型来探索VIDD。最后，我们将确认我们的初步证据，即microRNAs，特别是microRNA-320a，通过FOXO介导的E3泛素连接酶阿托金和MuRF1的过表达，通过增加肌肉蛋白分解来影响VIDA。随后，我们将测试系统microRNA疗法对VIDA的治疗潜力。总体而言，这些实验将促进我们对VIDA/VIDD基本机制的理解，并通过在动物身上测试这些实验，朝着有效的临床治疗迈出实质性的一步。