Pathophysiology of sepsis-induced renal injury

脓毒症引起的肾损伤的病理生理学

基本信息

批准号：
8053389
负责人：
Pierre C Dagher
金额：
$ 31.05万
依托单位：
INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-05-15 至 2014-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8053389
关键词：
Acute Acute Kidney Failure Acute Renal Failure with Renal Papillary Necrosis Animals Anticoagulation Apoptosis Attention Biochemical Bone Marrow CD14 Antigen CD14 gene Cells Chimera organism Clinical Complex Development Endocytosis Endotoxins Failure Fluorescent Probes Functional disorder Future Health Healthcare Image Immune system Inflammation Inflammatory Injection of therapeutic agent Injury Intervention Kidney Kinetics Lead Life Ligation Lipopolysaccharides Liquid substance Measures Mediating Metabolic Microscopic Microscopy Modeling Molecular Mus Nature Organ failure Outcome Oxidative Stress Pathway interactions Phase Photons Process Puncture procedure Rattus Receptor Signaling Renal tubule structure Research Role Sepsis Signal Transduction Small Interfering RNA Staging TLR4 gene Techniques Therapeutic Time Tissues Toll-like receptors Tubular formation base cost cytokine endotoxin receptor hemodynamics improved insight kidney cell meetings mortality mouse model novel pifithrin prevent protein expression receptor success tool uptake

项目摘要

DESCRIPTION (provided by applicant): Gram negative sepsis remains a formidable clinical problem with an unacceptably elevated mortality despite decades of intensive research in the field. The multi organ failure that frequently sets in during sepsis often ushers a grim outcome that so far has been difficult to alter. The pathophysiology of acute kidney injury (AKI) in sepsis is thought to result from uncontrolled inflammation and a procoagulant state triggered by stimulation of Toll-like receptors (TLRs) on cells of the immune system. Nevertheless, interference with systemic inflammatory cytokines, anticoagulation therapy and vigorous hemodynamic support all met with little success in preventing AKI and improving overall mortality. It is the purpose of this proposal to explore a novel hypothesis regarding the pathophysiology of ARF and AKI in gram negative sepsis. The hypothesis proposes that AKI in systemic gram negative sepsis results in part from a direct interaction between endotoxin and renal tubular cells. In specific aim 1, we will measure the magnitude and distribution of tubule- endotoxin interactions in mice and rat models of systemic sepsis. Using 2 photon microscopy in live animals, along with novel fluorescent probes, we will measure tubular oxidative stress and apoptosis that result from direct tubular endotoxin uptake. To examine the pathophysiology of endotoxin-tubule interactions in the absence of systemic cytokines, we will generate chimera mice lacking systemic TLR4. Finally, the role of p53 in mediating apoptosis and oxidative stress will be examined through protein expression, co localization and inhibitory studies. In specific aim 2, we will determine the roles of TLR4, CD14 and receptor-independent fluid-phase endocytosis in tubular endotoxin uptake with the powerful tool of targeted live delivery of receptor-specific siRNA. The impact of acute TLR4 or CD14 knockdown on endotoxin uptake, oxidative stress and apoptosis will be determined with live 2 photon imaging studies as well as traditional ex vivo techniques. Chimera mice lacking renal TLR4 or CD14 will provide an additional approach to examine the role of these molecules in tubular endotoxin uptake. These specific aims will determine the magnitude, impact and mechanism of the interaction between endotoxin and tubular cells. We believe they will establish a novel and so far unexplored mechanism underlying sepsis-induced renal injury. By exposing such a new mechanism, our studies could be at the basis of future therapies that aim at interfering with the direct detrimental effects of endotoxin on renal cells. PUBLIC HEALTH RELEVANCE: Acute kidney failure and sepsis represent a major healthcare burden in the US with a cost exceeding millions of dollars yearly.

描述（由申请人提供）：尽管在该领域进行了数十年的深入研究，革兰氏阴性脓毒症仍然是一个可怕的临床问题，其死亡率高得令人无法接受。脓毒症期间经常发生的多器官衰竭往往会带来迄今为止难以改变的严峻后果。脓毒症中急性肾损伤 (AKI) 的病理生理学被认为是由不受控制的炎症和免疫系统细胞上 Toll 样受体 (TLR) 刺激引发的促凝血状态引起的。然而，干扰全身炎症细胞因子、抗凝治疗和强有力的血流动力学支持在预防 AKI 和改善总体死亡率方面收效甚微。本提案的目的是探索关于革兰氏阴性脓毒症中 ARF 和 AKI 病理生理学的新假设。该假设提出，系统性革兰氏阴性脓毒症中的 AKI 部分是由内毒素和肾小管细胞之间的直接相互作用造成的。在具体目标 1 中，我们将测量全身性脓毒症小鼠和大鼠模型中肾小管-内毒素相互作用的程度和分布。在活体动物中使用 2 光子显微镜以及新型荧光探针，我们将测量直接肾小管内毒素摄取导致的肾小管氧化应激和细胞凋亡。为了检查在缺乏系统性细胞因子的情况下内毒素-小管相互作用的病理生理学，我们将产生缺乏系统性 TLR4 的嵌合体小鼠。最后，将通过蛋白质表达、共定位和抑制研究来检查 p53 在介导细胞凋亡和氧化应激中的作用。在具体目标 2 中，我们将利用受体特异性 siRNA 靶向活体递送的强大工具，确定 TLR4、CD14 和受体独立的液相内吞作用在肾小管内毒素摄取中的作用。急性 TLR4 或 CD14 敲低对内毒素摄取、氧化应激和细胞凋亡的影响将通过实时 2 光子成像研究以及传统的离体技术来确定。缺乏肾 TLR4 或 CD14 的嵌合小鼠将提供另一种方法来检查这些分子在肾小管内毒素摄取中的作用。这些具体目标将决定内毒素与肾小管细胞之间相互作用的程度、影响和机制。我们相信他们将建立一种新颖且迄今为止尚未探索的脓毒症肾损伤机制。通过揭示这种新机制，我们的研究可以为未来旨在干扰内毒素对肾细胞的直接有害影响的疗法奠定基础。公共健康相关性：急性肾衰竭和败血症是美国的主要医疗负担，每年造成的费用超过数百万美元。