Stable Isotope Approaches to the Understanding of Potassium Homeostasis

稳定同位素方法了解钾稳态

基本信息

批准号：
10431555
负责人：
JANG H. YOUN
金额：
$ 26.17万
依托单位：
UNIVERSITY OF SOUTHERN CALIFORNIA
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-03-15 至 2024-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10431555
关键词：
Acute Address Affect Aldosterone Animals Biochemical Blood Brain Buffers Cardiovascular Physiology Cardiovascular system Cells Chronic Collaborations Communication Development Dietary Potassium Elements Epinephrine Equilibrium Event Excretory function Exercise Extracellular Fluid Future Grant Half-Life Homeostasis Hormones In Vitro Incubated Individual Inductively Coupled Plasma Mass Spectrometry Insulin Intake Intracellular Fluid Isotopes Kidney Lead Life Liquid substance Measurement Measures Methodology Methods Modeling Molecular Muscle Na(+)-K(+)-Exchanging ATPase Nature Neurophysiology - biologic function Organ Pancreas Patients Plasma Play Potassium Potassium Channel Radioactive Tracers Radioactivity Rattus Regulation Role Sampling Signal Transduction Skeletal Muscle Technology Text Time Tissues Tracer Universities Variant Work analytical method extracellular heart function hyperkalemia in vivo innovation neuromuscular function novel strategies novel therapeutics stable isotope tool

项目摘要

Project Summary Potassium (K+) homeostasis is critical for normal cardiovascular and neuromuscular function, and disturbances in K+ homeostasis (e.g., hyperkalemia) can lead to life-threatening cardiovascular events. Extracellular K+ homeostasis is maintained by renal and extrarenal mechanisms. The kidneys have a remarkable capacity to regulate K+ excretion to match K+ intake, playing the major role in maintaining chronic K+ balance. In addition, extrarenal tissues (mainly skeletal muscle, the major K+ store) provide K+ buffering capacity by shifting K+ between the extracellular and intracellular fluids. Furthermore, gut sensing of dietary K+ appears to generate signals for regulating renal K+ excretion and extrarenal K+ shift. Thus, extracellular K+ homeostasis involves multiple organs and tissues, their adaptation to dietary K+ intake, and crosstalk among them. Despite marked progress in this field in recent decades, many critical issues concerning K+ homeostatic mechanisms remain unresolved due to a lack of appropriate methodology. A main limitation in studies of extracellular K+ homeostasis is an inability to quantify K+ fluxes in vivo. Although previous studies quantified K+ fluxes using 86Rb, a radioactive tracer for K+, radioactivity exposure and short half-life of 86Rb have limited its use to in vitro studies. Stable isotopes of a wide range of elements have been used to quantify fluxes of various substrates or blood constituents in vivo. However, in spite of the existence of two stable isotopes of K+ in nature (39K, 93.3% and 41K, 6.7%), this approach has not been applied to the study of K+ homeostasis in vivo due to analytical limitations. Dr. John Higgins, a geochemist at Princeton University, developed analytical methods for determining the ratio of stable K+ isotopes (41K/39K) in natural samples using inductively coupled plasma mass spectrometry. This state-of-the-art technology provides the opportunity to determine K+ fluxes in vivo using stable isotopes (i.e., without using radioactive tracers). The objective of the current proposal is to develop and validate this new approach for estimating whole-body K+ fluxes in vivo and extend it to assess K+ transport activities in individual tissues. If successfully developed, these new cutting-edge approaches will open new doors to answering important questions and filling gaps in K+ homeostatic mechanisms in vivo. These stable isotope approaches will be highly innovative, as they allow whole-body and in vitro K+ flux analyses that were infeasible with any conventional approaches, including those with 86Rb.

项目概要钾 (K+) 稳态对于正常心血管和神经肌肉功能至关重要，并且 K+ 稳态紊乱（例如高钾血症）可导致危及生命的心血管事件。细胞外 K+ 稳态由肾脏和肾外机制维持。肾脏有非凡的作用调节 K+ 排泄以匹配 K+ 摄入量的能力，在维持慢性 K+ 平衡中发挥着重要作用。在此外，肾外组织（主要是骨骼肌，主要的 K+ 储存）通过转移提供 K+ 缓冲能力细胞外液和细胞内液之间的 K+。此外，肠道对膳食 K+ 的感知似乎会产生调节肾 K+ 排泄和肾外 K+ 转移的信号。因此，细胞外 K+ 稳态涉及多个器官和组织、它们对膳食 K+ 摄入量的适应以及它们之间的串扰。尽管标有尽管近几十年来该领域取得了进展，但有关 K+ 稳态机制的许多关键问题仍然存在由于缺乏适当的方法而未能解决。细胞外 K+ 稳态研究的主要局限性无法量化体内 K+ 通量。尽管之前的研究使用 86Rb（一种放射性物质）来量化 K+ 通量。 K+ 示踪剂、放射性暴露和 86Rb 的半衰期短限制了其在体外研究中的使用。稳定的多种元素的同位素已用于量化各种底物或血液的通量体内的成分。然而，尽管自然界中存在两种稳定的 K+ 同位素（39K、93.3% 和 41K， 6.7%），由于分析限制，该方法尚未应用于体内 K+ 稳态的研究。普林斯顿大学地球化学家约翰·希金斯博士开发了确定该比率的分析方法使用电感耦合等离子体质谱法测定天然样品中的稳定 K+ 同位素 (41K/39K)。这最先进的技术提供了使用稳定同位素（即，不使用放射性示踪剂）。当前提案的目标是开发和验证这一新的体内估计全身 K+ 通量的方法，并将其扩展到评估个体 K+ 转运活动组织。如果成功开发，这些新的尖端方法将为回答问题打开新的大门体内 K+ 稳态机制的重要问题和填补空白。这些稳定同位素方法将具有高度创新性，因为它们可以进行全身和体外 K+ 通量分析，而这是任何方法都无法实现的传统方法，包括 86Rb 的方法。