Prevention of Fracture Healing Failure in Alcohol Abusers

预防酗酒者骨折愈合失败

• 批准号: 8398367
• 负责人: DENNIS ABRAHAM CHAKKALAKAL
• 金额: --
• 依托单位: OMAHA VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8398367
• 关键词: 20 year old; Abstinence; Acetylcysteine; Affect; Age; Age of Onset; Age-Months; Alcohol abuse; Alcohol consumption; Alcoholism; Alcohols; Animal Model; Animals; Antidotes; Antioxidants; Binding; Bone Regeneration; Boxing; Cartilage; Cell physiology; Cells; Chronic; Cicatrix; Clinical; Clinical Research; Clinical Treatment; Cysteine; DNA Repair; Data; Diet; Enhancers; Enzymes; Equilibrium; Ethanol; Ethanol Metabolism; Experimental Models; Failure; Femoral Fractures; Femur; Fracture; Fracture Healing; Free Radical Scavenging; Genetic Transcription; Glutathione; Healed; Heavy Drinking; Host Defense; Human; Incidence; Infection; Inflammatory; Inflammatory Response; Injection of therapeutic agent; Injury; Intake; Knowledge; Lymphoid; Mature Bone; Mechanics; Mediating; Methods; Modeling; Molecular; Natural regeneration; Operative Surgical Procedures; Orthopedics; Osteoblasts; Osteogenesis; Osteotomy; Outcome; Oxidants; Oxidative Stress; Pathway interactions; Patients; Persons; Phase; Population; Prevention; Protocols documentation; Rattus; Reactive Oxygen Species; Recording of previous events; Recovery; Reducing diet; Research Design; Signal Transduction; Site; Staging; Subcutaneous Injections; TCF Transcription Factor; Testing; Time; Tissues; Translations; Veterans; alcohol abstinence; alcohol abuser; alcohol exposure; base; beta catenin; binge drinking; bone healing; chronic alcohol ingestion; cytokine; design; dietary antioxidant; dietary restriction; experience; feeding; fibrogenesis; healing; innovation; intramembranous bone formation; non-compliance; nutrition; pathogen; prevent; problem drinker; public health relevance; research study; response; restoration; sample fixation; skeletal; tissue repair

DESCRIPTION (provided by applicant): Fracture patients with a history of chronic alcohol abuse have a higher incidence of delayed unions and non-unions. In experimental models of fracture healing alcohol inhibits new bone formation in the fracture site and promotes fibrogenesis, accumulation of immature cartilage, decreased osteoblast number and function, and decreased stiffness and strength of the repair tissue. Thus, alcohol promotes scar tissue formation instead of bone regeneration in the fracture site by interfering with cellular mechanisms in both the direct ("intramembranous") and indirect (endochondral) pathways of new bone formation. Inhibition of new bone formation and the resulting deficiency in fracture healing in rats given ethanol by subcutaneous injection in a binge-drinking protocol was restored to normal healing by injection of the dietary antioxidant n-acetylcysteine (NAC) during two weeks after fracture. Hypothesis. We hypothesize that treatment with the antioxidant n-acetylcysteine (NAC) will restore the balance of oxidative stress and antioxidant response in the fracture site and thus restore the normal fracture healing sequence including the initial inflammatory phase, Wnt/beta catenin signaling, and endochondral and intramembranous ossification to prevent failure of fracture healing in chronically ethanol-fed rats. Specific Aims. (1) Determine the effects of alcohol consumption/ abstinence and restriction of diet intake before and after "fracture" on restoration of normal bone repair outcome in untreated and NAC-treated rats. (2) Determine whether oxidative stress is increased by both ethanol and reduced diet intake and whether post- surgery abstinence from ethanol and/or NAC treatment will restore the oxidant-antioxidant balance, inflammatory response, Wnt/beta catenin signaling, endochondral ossification, and intramembranous ossification observed in normal fracture healing. Research Design. Rats 9 months of age, which corresponds to average human age of 20 years, will be fed the Lieber-DeCarli ethanol diet daily for 16 weeks. Transverse osteotomy will be performed at middiaphysis of one femur of the rat. The femur will be immobilized by internal fixation. This model will be created in groups of rats that have been given the ethanol diet and ethanol-free (control) diet. In Aim 1, the outcome of healing will be evaluated at 16 weeks post surgery by mechanical testing. The age of the rat at this time will be 17 months, which corresponds approximately to human age of 60 years. We will determine if 14 days of NAC treatment prevents the ethanol-induced inhibition of bone healing and if this result is also achieved merely by stopping the ethanol feeding after surgery and allowing the animals to consume the control diet ad libitum. In Aim 2, we will obtain preliminary data to answer the following questions, which will provide the basis for a full-scale project leading to clinical translation: (1) In fracture healing failure associated with chronic alcoholism how does alcohol-induced oxidative stress affect (a) recruitment of inflammatory cells and their cytokine expressions that are critical for fracture healing? (b) Wnt/beta catenin signaling that mediates new bone formation? (2) What are the specific mechanisms of action of NAC that restore Wnt/beta catenin signaling and new bone formation in the context of chronic alcoholism. PUBLIC HEALTH RELEVANCE: Persons with a long history of chronic and excessive alcohol consumption ("alcohol abusers") experience complications often leading to failure of fracture healing. Experimental studies show that alcohol causes cellular abnormalities in the early stage of fracture healing leading to this failure. In the proposed project we will evaluate the efficacy of the antioxidant n-acetylcysteine (NAC) to prevent the failure of fracture healing in alcohol abusers. In a recent study it was found that inhibition of new bone formation in closed femoral fractures created in rats following binge alcohol exposure could be prevented by administration of NAC during 2 weeks after fracture.The efficacy of NAC for clinical treatment of a large variety of conditions has been documented in a large number of clinical studies during the past two decades. It is well tolerated, has well-defined mechanisms of action and is acknowledged as a safe antidote for cysteine/glutathione deficiency .

描述（由申请人提供）： 有长期酗酒史的骨折患者延迟愈合和不愈合的发生率较高。在骨折愈合的实验模型中，酒精抑制骨折部位的新骨形成并促进纤维形成、未成熟软骨的积累、成骨细胞数量和功能减少以及修复组织的刚度和强度降低。因此，酒精通过干扰新骨形成的直接（“膜内”）和间接（软骨内）途径中的细胞机制，促进疤痕组织形成而不是骨折部位的骨再生。在暴饮暴食方案中皮下注射乙醇的大鼠，新骨形成受到抑制并由此导致骨折愈合不足，但在骨折后两周内注射膳食抗氧化剂 n​​-乙酰半胱氨酸 (NAC) 可恢复正常愈合。假设。我们假设抗氧化剂 n​​-乙酰半胱氨酸 (NAC) 治疗将恢复骨折部位氧化应激和抗氧化反应的平衡，从而恢复正常的骨折愈合顺序，包括初始炎症阶段、Wnt/β 连环蛋白信号传导以及软骨内和膜内骨化，以防止长期乙醇喂养的大鼠骨折愈合失败。具体目标。 (1)确定“骨折”前后饮酒/戒酒和限制饮食对正常骨恢复的影响 未经治疗和 NAC 治疗的大鼠的修复结果。 (2)确定乙醇和减少饮食摄入是否会增加氧化应激，以及手术后戒除乙醇和/或NAC治疗是否会恢复正常骨折愈合中观察到的氧化-抗氧化平衡、炎症反应、Wnt/β连环蛋白信号传导、软骨内骨化和膜内骨化。研究设计。 9 个月大的老鼠（相当于人类平均年龄 20 岁）将每天喂食 Lieber-DeCarli 乙醇饮食，持续 16 周。将在大鼠一根股骨的中干处进行横向截骨术。股骨将通过内固定固定。该模型将在给予乙醇饮食和无乙醇（对照）饮食的大鼠组中创建。在目标 1 中，将在术后 16 周通过机械测试评估愈合结果。此时老鼠的年龄为 17 个月，大约相当于人类 60 岁的年龄。我们将确定 14 天的 NAC 治疗是否可以防止乙醇诱导的骨愈合抑制，以及是否仅通过手术后停止乙醇饲喂并允许动物随意食用对照饮食即可实现这一结果。在目标2中，我们将获得初步数据来回答以下问题，这将为导致临床转化的全面项目提供基础：（1）在与慢性酒精中毒相关的骨折愈合失败中，酒精诱导的氧化应激如何影响（a）对骨折愈合至关重要的炎症细胞及其细胞因子表达的募集？ (b) 介导新骨形成的 Wnt/β 连环蛋白信号传导？ (2) NAC在慢性酒精中毒的情况下恢复Wnt/β连环蛋白信号传导和新骨形成的具体作用机制是什么。 公共卫生相关性： 长期长期过量饮酒的人（“酒精滥用者”）会出现并发症，通常会导致骨折愈合失败。实验研究表明，酒精会导致骨折愈合早期的细胞异常，从而导致骨折愈合失败。在拟议的项目中，我们将评估抗氧化剂 n​​-乙酰半胱氨酸 (NAC) 预防酗酒者骨折愈合失败的功效。在最近的一项研究中发现 大鼠因酗酒而造成的闭合性股骨骨折，骨折后 2 周内给予 NAC 可以防止新骨形成受到抑制。过去 20 年来，大量临床研究已记录了 NAC 对多种疾病临床治疗的功效。它具有良好的耐受性，具有明确的作用机制，被认为是半胱氨酸/谷胱甘肽缺乏症的安全解毒剂。