Measuring changes in substrate utilization in the myocardium in response to fasting using hyperpolarized [1-(13)C]butyrate and [1-(13)C]pyruvate.
Measuring changes in substrate utilization in the myocardium in response to fasting using hyperpolarized [1-(13)C]butyrate and [1-(13)C]pyruvate.
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DOI：
10.1038/srep25573
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发表时间：
2016-05-06
影响因子：
4.6
通讯作者：
Comment A
中科院分区：
文献类型：
--
作者：
Bastiaansen JA;Merritt ME;Comment A
心功能不全通常与ATP产生的底物偏好的转变有关。超极化（HP）13 C磁共振波谱（MRS）由于其高灵敏度和特异性而具有独特的实时检测体内代谢变化的能力。在此，使用HP [1- 13 C]丙酮酸和[1- 13 C]丁酸的方案用于测量体内碳水化合物与脂肪酸代谢。在尾静脉注射后，在9.4 T下研究了进食和禁食Sprague道利大鼠（n = 36）的代谢变化。丙酮酸盐和丁酸盐竞争乙酰辅酶A的产生，禁食后[13 C]碳酸氢盐（−48%），[1- 13 C]乙酰肉毒碱（+113%）和[5- 13 C]谷氨酸盐（−63%）的显著变化证明了这一点。丁酸摄取不受空腹，如[1- 13 C]丁酰肉碱所示。线粒体假生酮促进了酮体[1- 13 C]乙酰乙酸酯和[1- 13 C]β-羟基丁酸酯的标记，没有真正生酮的证据。HP [1- 13 C]乙酰乙酸盐在禁食时增加（250%），但在丙酮酸盐共注射期间减少（−82%）。结合HP 13 C技术和单独显像剂的联合给药，可以无创地同时监测脂肪酸和碳水化合物的氧化。该协议说明了一种新的方法，通过不同的酶途径同时评估代谢通量，并使机械研究的变化心肌能量学往往与疾病。
Cardiac dysfunction is often associated with a shift in substrate preference for ATP production. Hyperpolarized (HP) 13C magnetic resonance spectroscopy (MRS) has the unique ability to detect real-time metabolic changes in vivo due to its high sensitivity and specificity. Here a protocol using HP [1-13C]pyruvate and [1-13C]butyrate is used to measure carbohydrate versus fatty acid metabolism in vivo. Metabolic changes in fed and fasted Sprague Dawley rats (n = 36) were studied at 9.4 T after tail vein injections. Pyruvate and butyrate competed for acetyl-CoA production, as evidenced by significant changes in [13C]bicarbonate (−48%), [1-13C]acetylcarnitine (+113%), and [5-13C]glutamate (−63%), following fasting. Butyrate uptake was unaffected by fasting, as indicated by [1-13C]butyrylcarnitine. Mitochondrial pseudoketogenesis facilitated the labeling of the ketone bodies [1-13C]acetoacetate and [1-13C]β-hydroxybutyryate, without evidence of true ketogenesis. HP [1-13C]acetoacetate was increased in fasting (250%) but decreased during pyruvate co-injection (−82%). Combining HP 13C technology and co-administration of separate imaging agents enables noninvasive and simultaneous monitoring of both fatty acid and carbohydrate oxidation. This protocol illustrates a novel method for assessing metabolic flux through different enzymatic pathways simultaneously and enables mechanistic studies of the changing myocardial energetics often associated with disease.