Metabolic impact of Intralipid on synaptic function as a mechanism of resuscitation in local anesthetic systemic toxicity

脂肪乳对突触功能的代谢影响作为局麻药全身毒性复苏的机制

• 批准号: 10572885
• 负责人: Daniel Charles Cook
• 金额: $ 19.5万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2028-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10572885
• 关键词: Action Potentials; Adenosine Triphosphate; Agreement; Anesthetics; Antidotes; Belief; Biosensor; Brain; Bypass; Calcium; Cardiac; Cardiotoxicity; Cardiovascular system; Carnitine; Central Nervous System; Cephalic; Clinical; Convulsants; Data; Dose; Effectiveness; Emulsions; Environment; Fat emulsion; Flavins; Formulation; Functional disorder; Funding; Glucose; Glycolysis; Glycolysis Inhibition; Guidelines; Heart Arrest; Hypoglycemia; ICAM3 gene; Image; Impairment; In Vitro; Institution; Intravenous Fat Emulsions; Investigation; Ischemia; Length; Lidocaine; Life; Lipids; Local Anesthetics; Measurement; Measures; Mediating; Medical; Medicine; Medium chain triglycerides; Mentors; Metabolic; Metabolic stress; Metabolism; Mitochondrial Proteins; Modeling; Molecular; Molecular Target; Mus; Muscle; Nerve; Neurobiology; Neurologic; Neurons; Neuropharmacology; Nonesterified Fatty Acids; Optical reporter; Overdose; Oxidative Phosphorylation; Parenteral Nutrition; Pathway interactions; Perfusion; Pharmaceutical Preparations; Phase; Phenotype; Phospholipids; Prevention; Production; Publications; Pyruvate; Recommendation; Recycling; Research; Research Proposals; Resuscitation; Role; Seizures; Site; Sodium Channel; Soybean Oil; Symptoms; Synapses; Synaptic Vesicles; Syndrome; Testing; Therapeutic; Toxic effect; Triglycerides; aqueous; career; clinical application; comparative efficacy; deprivation; design; excitatory neuron; falls; glucose metabolism; improved; in vivo; inhibitory neuron; knock-down; lipid transport; lipoprotein lipase; metabolic imaging; mitochondrial dysfunction; neurotoxic; neurotoxicity; neurotransmission; optical imaging; oxidation; pharmacologic; prevent; small hairpin RNA; synaptic function; systemic toxicity; voltage

Project Summary Intravenous lipid emulsions (ILEs) are important therapies. Though designed for parenteral nutrition, they were discovered to be an antidote for local anesthetic systemic toxicity (LAST). With rising intravascular concentrations of local anesthetics (LAs), which canonically inhibit voltage-gated sodium channels (Nav), symptoms of central nervous system (CNS) toxicity progress to seizures, and cardiac arrest may ensue. LAST is a major clinical challenge, and the identification of ILEs as treatment was a breakthrough that has made use of LAs safer. Despite this important role, the molecular mechanisms by which ILEs treat LAST are not fully understood. Furthermore, there is a paucity of studies examining whether Intralipid®, the emulsion recommended in medical guidelines that is composed of long-chain triglycerides from soybean oil, is the best choice. The most simplistic model for the effects of ILEs is that they form an intravascular compartment to partition LAs and lower the effect-site concentration, but the degree to which concentrations fall in the aqueous phase is debated. A competing hypothesis with strong evidence in cardiac models proposes ILEs serve as a fuel via β-oxidation of triglycerides (TGs), overcoming mitochondrial dysfunction caused by LAs. This mechanism has been dismissed to explain reversal of CNS dysfunction because of the dogmatic belief that neurons rely on glucose metabolism. Additionally, neurotoxicity due to LAs has been attributed, with limited evidence, to preferential block of inhibitory neurons, but important effects in the CNS are unexplained by this hypothesis. My preliminary in vitro data shows that neurons can use Intralipid® to sustain synaptic function in the absence of other fuels, supporting the metabolic hypothesis of ILEs for LAST in the CNS. This research proposal will test the hypothesis that ILEs reverse neurotoxicity by overcoming LA-induced mitochondrial dysfunction. The experimental plan will systematically investigate the capacity for neurons to metabolize components of ILEs. In doing so, I will comprehensively investigate the suitability of lipids to fuel synaptic function. In Aim 1, I will use my developing expertise in optical imaging of cultured neurons expressing genetically-encoded biosensors to compare lipids by their ability to sustain synaptic vesicle recycling and produce ATP when deprived of glucose. Lipids will be tested as emulsions of both long- and medium-chain TGs and free fatty acids of different lengths and saturation. In Aim 2, a metabolically optimized emulsion will be compared in culture to Intralipid® in its ability to reverse LA-induced synaptic dysfunction. In Aim 3, the optimized emulsion will be compared to Intralipid® in mice, quantifying effects on seizures with widefield calcium imaging, local field potentials, and autofluorescence flavin imaging of metabolic activity. My five-year research and career proposals capitalize on my excellent mentors and institutional environment. I will acquire the publication record and expertise necessary for recognition as a national leader in anesthetic neuropharmacology and prepare for independent investigation with R01 funding.

项目摘要 静脉注射脂肪乳剂（ILE）是重要的治疗方法。虽然设计用于肠外营养， 被发现是局部麻醉剂全身毒性（LAST）的解毒剂。随着血管内 局部麻醉剂（LA）浓度，其典型地抑制电压门控钠通道（Nav）， 中枢神经系统（CNS）毒性的症状进展为癫痫发作，随后可能发生心脏骤停。最后 是一个重大的临床挑战，将肠梗阻作为治疗手段是一个突破， 更安全。尽管这一重要作用，但肠梗阻治疗LAST的分子机制并不完全清楚。 明白此外，很少有研究检查乳剂Intralid ® 在医学指南中推荐的是由大豆油中的长链甘油三酯组成的，是最好的 选择肠梗阻效应的最简单模型是它们形成血管内隔室， 分区LA和降低效应部位的浓度，但浓度下降的程度，在水 阶段进行辩论。一个在心脏模型中有强有力证据的竞争性假设提出，ILE作为燃料， 通过甘油三酯（TG）的β-氧化，克服由LA引起的线粒体功能障碍。这一机制 已经被驳回解释中枢神经系统功能障碍的逆转，因为教条式的信念，神经元依赖于 葡萄糖代谢此外，在证据有限的情况下，LA引起的神经毒性被归因于 优先阻断抑制性神经元，但这一假设无法解释中枢神经系统中的重要作用。我 初步的体外数据显示，神经元可以使用Intradroid ®在缺乏神经元的情况下维持突触功能。 其他燃料，支持CNS中LAST的ILE代谢假说。 这项研究计划将测试这一假设，即肠梗阻逆转神经毒性，通过克服LA诱导的 线粒体功能障碍实验计划将系统地研究神经元的能力， 代谢肠梗阻的成分。在这样做的过程中，我将全面调查脂质燃料的适用性 突触功能在目标1中，我将利用我在培养神经元表达的光学成像方面的专业知识， 基因编码的生物传感器，通过它们维持突触囊泡再循环的能力来比较脂质， 产生ATP。脂质将作为长链和中链TG的乳剂进行测试 以及不同长度和饱和度的游离脂肪酸。在目标2中，代谢优化的乳剂将 在其逆转LA诱导的突触功能障碍的能力方面，与Intralid ®进行比较。在目标3中， 在小鼠中将乳剂与Intralidid ®进行比较，用宽视野钙成像定量对癫痫发作的影响， 局部场电位和代谢活动的自发荧光黄素成像。我五年的研究和职业生涯 我的提案充分利用了我优秀的导师和机构环境。我会拿到出版记录 和必要的专业知识，作为麻醉神经药理学的国家领导者，并准备 R 01资助的独立调查。