Mechanisms of Impaired Wound Healing Due to Ischemia

缺血导致伤口愈合受损的机制

• 批准号: 8195929
• 负责人: Lisa J Gould
• 金额: --
• 依托单位: JAMES A. HALEY VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-01 至 2012-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8195929
• 关键词: 3-nitrotyrosine; Acute; Affect; Age; Age-Months; Aged, 80 and over; Aging; American; Anti-Inflammatory Agents; Anti-inflammatory; Antioxidants; Apoptosis; Biological Assay; Biological Availability; Buffers; Cell Death; Cell Proliferation; Cell Survival; Cell physiology; Cells; Chronic; Collagen; Comorbidity; Confocal Microscopy; Cuprozinc Superoxide Dismutase; Data; Diabetes Mellitus; Elderly; Endothelial Cells; Enzymes; Epidemic; Epithelial Cells; Equilibrium; Excision; Extracellular Matrix; Fibroblasts; Foundations; Gelatinase B; Generations; Glutamate-Cysteine Ligase; Glutathione; Goals; Healed; Health; Health system; Healthcare; Healthcare Systems; Heart Diseases; Homeostasis; Human; Hydrogen Peroxide; Hyperoxia; Hypoxia; Immunoblotting; Immunohistochemistry; Impaired wound healing; Incidence; Indium; Individual; Inflammation; Inflammation Mediators; Inflammatory; Inflammatory Response; Intermittent Claudication; Interstitial Collagenase; Ischemia; Isoenzymes; Lead; Life; Limb structure; Liquid substance; Literature; Lower Extremity; Lucigenin; Matrix Metalloproteinase Inhibitor; Matrix Metalloproteinases; Measurement; Measures; Messenger RNA; Modeling; Molecular; Morbidity - disease rate; NBL1 gene; Natural regeneration; Necrosis; Nitrates; Nitric Oxide; Nitrites; Nitrogen; Oxidation-Reduction; Oxidative Stress; Oxygen; Pathogenesis; Pathology; Patients; Peptide Hydrolases; Perfusion; Peripheral arterial disease; Peroxonitrite; Physiological; Play; Population; Predisposition; Prevalence; Procedures; Process; Production; Protease Inhibitor; Protein Isoforms; Proteins; Public Health; Rattus; Reaction; Reactive Nitrogen Species; Reactive Oxygen Species; Reperfusion Therapy; Residual state; Role; Signaling Molecule; Skin; Skin Aging; Stress; Superoxide Dismutase; Superoxides; Surgical Flaps; System; Testing; Time; Tissue Extracts; Tissue Model; Tissues; Vascular Diseases; Vascular blood supply; Venous Insufficiency; Veterans; Water; Wound Healing; abstracting; angiogenesis; catalase; cell motility; cost; cytokine; effective therapy; enzyme activity; healing; improved; inhibitor/antagonist; keratinocyte; mRNA Expression; middle age; migration; mimetics; nitration; novel; oxidation; oxidative damage; pressure; prevent; protein expression; response; superoxide dismutase 1; synthetic enzyme; tissue trauma; wound; young adult

PROJECT SUMMARY/ABSTRACT Treatment of chronic, non-healing wounds is a major public health issue that is growing as our population ages. It is estimated that 5 million Americans suffer from chronic wounds, costing the US health system $20 to 25 billion a year. Chronic wounds currently affect about 15% of older Americans. However, because the number of individuals 65 and older is the fastest growing population and co-morbid conditions that result in tissue ischemia, such as heart disease, peripheral arterial disease and diabetes, are more common in the elderly, this figure is expected to steadily increase. The central hypothesis of this project is that tissue ischemia disrupts the delicate balance between the production of reactive oxygen species and their removal by endogenous antioxidants, resulting in oxidative stress, altered composition of the extracellular matrix and impaired healing. We will also explore the hypothesis that despite physiologic changes associated with aging that affect wound healing, the primary reason for the increased prevalence of impaired wound healing in the elderly is tissue ischemia. Using a rat ischemic flap model we will: 1) Test the hypothesis that dysregulation of the endogenous antioxidant system results in a net excess of reactive oxygen species in the ischemic wound, 2) Test the hypothesis that manipulating the redox balance in ischemic wounds can improve healing. 3) Test the hypothesis that the redox balance affects matrix metalloproteinase activity. Procedures to be Used: The rat model of tissue ischemia developed and validated by Dr. Gould (Wound Repair and Regeneration, 2005) will be used to measure oxidative stress, endogenous antioxidants, proteases, and protease inhibitors in ischemic and non-ischemic wounds of young, middle aged and old rats, comparing these factors to the extracellular matrix composition. Exogenous antioxidant mimetics will be tested for their ability to alter the redox balance and improve wound healing. The contribution of specific cell populations in redox homeostasis will be characterized using a novel live tissue assay. To further characterize the mechanisms that impair cellular function during oxidative stress and verify that these mechanisms are consistent between species, primary human fibroblasts from donors of different ages will be grown under conditions of hypoxia, normoxia and hyperoxia. Utilizing specific inhibitors of endogenous antioxidants, levels of inflammatory mediators, proteases, matrix production and destruction and the impact on cell migration will be determined. Significance: Our long term goal is to elucidate the cellular mechanisms that result in chronic wounds so that rational therapies can be developed to improve healing or prevent these wounds altogether. The molecular changes that occur in wound healing, particularly in the elderly who more commonly have tissue ischemia, are poorly understood.

项目摘要/摘要 治疗慢性、不可愈合的伤口是一个日益严重的公共卫生问题 随着我们人口的老龄化。据估计，有500万美国人患有慢性创伤， 每年给美国卫生系统造成200至250亿美元的损失。慢性伤口目前影响大约 15%的美国老年人。然而，由于65岁及以上的个人数量是 增长最快的人口和导致组织缺血的共病情况，如心脏 疾病，外周动脉疾病和糖尿病，在老年人中更常见，这个数字是 预计将稳步增长。 该项目的中心假设是，组织缺血破坏了精致的 在产生活性氧物种和清除它们之间的平衡 内源性抗氧化剂，导致氧化应激，改变了 细胞外基质和受损的愈合。我们还将探讨这样的假设：尽管 与衰老相关的影响伤口愈合的生理变化，是导致 在老年人中，创面愈合受损的患病率增加是组织缺血。 使用大鼠缺血皮瓣模型，我们将： 1)检验内源性抗氧化剂系统失调导致净网的假设 在缺血的伤口中有过多的活性氧， 2)验证这样一种假设，即操纵缺血创面的氧化还原平衡可以改善 治愈。 3)检验氧化还原平衡影响基质金属蛋白酶活性的假设。 使用的方法：由Dr。 古尔德(创伤修复和再生，2005)将被用来测量氧化应激， 脑缺血和非脑缺血的内源性抗氧化剂、蛋白水解酶和蛋白水解酶抑制物 幼年、中年和老年大鼠的创伤，将这些因素与细胞外基质进行比较 组成。将测试外源抗氧化剂模拟物改变氧化还原的能力。 平衡和促进伤口愈合。特定细胞群在氧化还原过程中的作用 动态平衡将使用一种新的活组织分析来表征。为了进一步描述 氧化应激期间损害细胞功能的机制并验证这些 不同物种、不同供者的原代人类成纤维细胞的机制是一致的 AGEs将在低氧、常氧和高氧条件下生长。利用特定的 内源性抗氧化剂、炎症介质、蛋白酶、基质的抑制物水平 生产和销毁以及对细胞迁移的影响将得到确定。 意义：我们的长期目标是阐明导致慢性阻塞性肺疾病的细胞机制 因此，可以开发合理的治疗方法来促进愈合或防止这些伤口 总而言之。在伤口愈合过程中发生的分子变化，特别是在老年人中 常见的有组织缺血，都知之甚少。