Pathophysiology of sepsis-induced renal injury

脓毒症引起的肾损伤的病理生理学

• 批准号: 8450638
• 负责人: Pierre C Dagher
• 金额: $ 31.23万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-15 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8450638
• 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

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.

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令人生畏的临床问题，其死亡率高得不可接受。脓毒症期间经常发生的多器官衰竭通常会带来迄今为止难以改变的严峻结果。脓毒症中急性肾损伤（阿基）的病理生理学被认为是由不受控制的炎症和由免疫系统细胞上的Toll样受体（TLR）的刺激触发的促凝血状态引起的。然而，全身性炎症细胞因子的干预、抗凝治疗和强有力的血流动力学支持在预防阿基和改善总体死亡率方面几乎没有成功。本提案的目的是探索关于革兰氏阴性脓毒症中ARF和阿基的病理生理学的新假设。该假说提出，全身性革兰氏阴性脓毒症中的阿基部分由内毒素和肾小管细胞之间的直接相互作用引起。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-内毒素相互作用的大小和分布。在活体动物中使用双光子显微镜，沿着新型荧光探针，我们将测量由直接肾小管内毒素摄取引起的肾小管氧化应激和细胞凋亡。为了研究在缺乏全身性细胞因子的情况下内毒素-小管相互作用的病理生理学，我们将产生缺乏全身性TLR 4的嵌合体小鼠。最后，p53在介导细胞凋亡和氧化应激中的作用将通过蛋白质表达，共定位和抑制研究进行检查。在具体目标2中，我们将确定TLR 4，CD 14和受体非依赖性液相内吞作用在肾小管内毒素摄取中的作用，并使用受体特异性siRNA靶向活体递送的强大工具。急性TLR 4或CD 14敲低对内毒素摄取、氧化应激和细胞凋亡的影响将用活双光子成像研究以及传统的离体技术来确定。缺乏肾脏TLR 4或CD 14的嵌合体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。这些特定的目的将决定内毒素和肾小管细胞之间相互作用的大小、影响和机制。我们相信，他们将建立一个新的和迄今尚未探索的机制，脓毒症引起的肾损伤。通过揭示这种新的机制，我们的研究可能是未来治疗的基础，旨在干扰内毒素对肾细胞的直接有害作用。