IN VIVO 13C NMR SPECTROSCOPY

体内 13C 核磁共振波谱

• 批准号: 8363886
• 负责人: Craig R Malloy
• 金额: $ 25.73万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8363886
• 关键词: Acetic Acids; Acetyl Coenzyme A; Animals; Bicarbonates; Biological Markers; Biopsy; Blood; Brain; Carbon; Chemical Shift Imaging; Citric Acid Cycle; Clinical Investigator; Clinical Research; Communities; Computer software; Coupled; Data; Detection; Development; Equation; Fatty Acids; Foundations; Funding; Future; Glutamates; Goals; Grant; Heart; Human; Image; Ischemia; Ketones; Kinetics; Label; Magnetic Resonance Spectroscopy; Malignant Neoplasms; Measures; Metabolic; Metabolism; Methods; Modeling; Mus; Myocardium; NMR Spectroscopy; National Center for Research Resources; Neuroglia; Neurons; Nuclear; Pathway interactions; Patients; Physiological; Principal Investigator; Process; Pyruvate; Pyruvic Acid; Rattus; Reaction; Research; Research Infrastructure; Resources; Role; Skeletal Muscle; Source; Spectrum Analysis; System; Technology; Testing; Time; Tracer; Translations; United States National Institutes of Health; Urine; Volatile Fatty Acids; Water; Work; cost; design; feeding; human tissue; improved; in vivo; long chain fatty acid; multiplet; muscle metabolism; stable isotope; tool

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This TR&D project represents a substantially new direction for stable isotope work in the Resource. New methods and applications for 13C and 2H tracers have been developed in the Resource and applied widely. Until now the prospect of in vivo studies was limited, for the most part, to examination of blood or urine from humans, and tissue biopsies from experimental animals. Over the last 4 years UT Southwestern and this Resource have invested heavily in two technologies, the 7T and dynamic nuclear polarization, that enables translation to in vivo spectroscopy and imaging. The goal of this project is to further develop these enabling technologies to support current clinical research and to lay the foundation for human studies in the near future. Aim 1 is designed to investigate the utility of multiplet 13C NMR spectroscopy for analysis of citric acid cycle and glutamatergic fluxes in the brain. Integrated mathematical tools for analysis of large networks of metabolic processes occurring in more than one compartment will be developed. The focus will be the mammalian brain. The high information content of 13C NMR spectra provided by spin-coupled multiplets has not previously been used for analysis of kinetics in multiple compartments. A set of differential equations describing all 13C isotopomers of all relevant intermediates in glia and neurons has been developed. Consequently, any combination of 13C fractional enrichment or 13C multiplets, measured as a function of time, can be fit to derive fluxes. The advantage of this approach is fewer prior assumptions about the metabolic system and improved precision in the estimate of metabolic variables. Two models are under development that are suitable for analysis of brain spectra, one to analyze spectra collected over time (kinetic analysis), and a second for the analysis of a single spectrum at metabolic steady state. The software will be made available to the scientific community. Aim 2 will further develop MR spectroscopy at 7T for studies of brain and skeletal muscle metabolism. This project is designed to develop and refine spectroscopy at 7T for analysis of metabolism and detection of biomarkers in human skeletal muscle and brain. The major technical goal is installation of 2-channel parallel transmit capabilities for improved 1H spectroscopy and chemical shift imaging of the brain. 1H MR spectra from patients with brain malignancies will be correlated with 13C data obtained by biopsy. Broad band 1 H decoupling for 13C NMR spectroscopy of skeletal muscle will be refined, and a package of spectroscopy studies including 31p, 13C and 1H spectroscopy will be provided to clinical investigators in skeletal muscle metabolism. Aim 3 examines the interaction of ischemia and substrates in the 13C NMR spectrum of the heart. After exposure of the myocardium to [1-13C]pyruvate, the ratio 13C bicarbonate/[1-13C]lactate is sensitive to ischemia and to changes in the concentration competing physiological substrates such as long chain fatty acids and ketones. We will test whether 13C-enriched water soluble short chain fatty acids can be used to probe flux in the citric acid cycle of the heart independent of competing substrates. Isolated rat hearts will be supplied with physiological mixtures of long chain fatty acids and other substrates. Competition of a short chain fatty acid with physiological substrates for entry into the acetyl-CoA pool will be examined by 13C NMR isotopomer analysiS over a range of conditions. The optimal fatty acid will be tested in isolated mouse hearts and rat hearts as a suitable probe for the citric acid cycle after hyperpolarization of 13C in carbon 1, and detection of glutamate enriched in C5. Finally, the optimal molecule will be tested for 13C imaging in vivo against competing substrates. Aim 4 will investigate the feasibility of imaging anaplerosis with hyperpolarized 13C. Reaction pathways feeding carbon into the citric acid cycle for biosynthetic purposes are termed "anaplerotic sequences". These reactions playa central role in key synthetic processes yet there is no general method for specifically imaging these pathways. Hyperpolarized [U-13C]acetic acid and hyperpolarized [U-13C]pyruvic acid will be used to label carbons 4 and 5 of glutamate in the isolated heart. Since the effects of anaplerosis on the 13C spectrum of glutamate are due to changes in 13C enrichment in carbons 3, 2 and 1 of glutamate, flip-flop spectroscopy (FLOPSY-8) will probe 13C multiplets in protonated carbons of glutamate and measure in a few seconds the activity of anaplerotic reactions. The method will be validated with conventional isotopomer methods.

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 这一研发项目代表了资源中稳定同位素工作的一个实质上的新方向。~(13)C和~(2H)H示踪剂的新方法和新应用已在该资源中得到开发和广泛应用。到目前为止，活体研究的前景在很大程度上仅限于检查人类的血液或尿液，以及实验动物的组织活检。在过去的4年里，UT Southwest和This Resource在7T和动态核极化这两项技术上投入了大量资金，这两项技术可以转换为体内光谱和成像。该项目的目标是进一步开发这些使能技术，以支持当前的临床研究，并为不久的将来的人体研究奠定基础。 目的1研究多重~(13)C核磁共振波谱在分析脑内柠檬酸循环和谷氨酸能通量方面的应用。将开发综合数学工具，用于分析在多个隔室中发生的代谢过程的大型网络。重点将放在哺乳动物的大脑上。由自旋耦合多重态提供的高信息含量的~(13)C核磁共振谱以前从未被用于多室动力学分析。建立了一组描述胶质细胞和神经元中所有相关中间体的13C同位素异构体的微分方程式。因此，作为时间函数测量的~(13)C部分富集度或~(13)C倍数的任何组合都可以用来推导通量。这种方法的优点是对代谢系统的预先假设较少，并提高了对代谢变量的估计精度。目前正在开发两种适合分析大脑光谱的模型，一种是分析随时间收集的光谱(动力学分析)，另一种是分析代谢稳定状态下的单一光谱。该软件将向科学界提供。 AIM 2将在7T进一步开发磁共振波谱，用于研究大脑和骨骼肌代谢。该项目旨在开发和改进7T的光谱，用于分析人体骨骼肌和大脑中的代谢和生物标志物。主要的技术目标是安装2通道并行传输能力，以改进1H光谱和大脑的化学位移成像。脑部恶性肿瘤患者的~1H磁共振波谱将与活检获得的~(13)C数据相关联。将改进用于骨骼肌~(13)C核磁共振波谱的宽带~1H去偶联，并将向骨骼肌代谢的临床研究人员提供包括~(31)P、~(13)C和~(13)H波谱在内的一揽子波谱研究。 目的3研究心脏~(13)C核磁共振谱中缺血与底物的相互作用。心肌暴露于[1-13C]丙酮酸后，13C碳酸氢盐/[1-13C]乳酸的比值对缺血和竞争的生理底物(如长链脂肪酸和酮)的浓度变化敏感。我们将测试是否可以使用富含13C的水溶性短链脂肪酸来探测心脏柠檬酸循环中的通量，而不依赖于竞争底物。分离的大鼠心脏将被供应长链脂肪酸和其他底物的生理性混合物。短链脂肪酸与进入乙酰辅酶A池的生理底物的竞争将在一系列条件下通过13C核磁共振同位素分析来检查。最佳脂肪酸将在分离的小鼠心脏和大鼠心脏中进行测试，作为适合于柠檬酸循环的探针，在碳1中的13C超极化后，并检测到富含C5的谷氨酸。最后，最优分子将在体内与竞争底物进行13C成像测试。 目的4探讨超极化~(13)C成像复原术的可行性。以生物合成为目的将碳输入柠檬酸循环的反应路径被称为“逆流序列”。这些反应在关键的合成过程中发挥着核心作用，但还没有通用的方法来专门成像这些途径。超极化的[U-13C]醋酸和超极化的[U-13C]丙酮酸将被用来标记离体心中谷氨酸的碳4和碳5。由于逆反作用对谷氨酸~(13)C谱的影响是由于谷氨酸的碳3、碳2和碳1的~(13)C浓集的变化所致，因此，触发器光谱(Flopsy-8)将探测谷氨酸质子化碳中的~(13)C多重态，并在几秒钟内测量逆反反应的活性。该方法将用常规的同位异构体方法进行验证。