Miller Jack J, Ball Daniel R, Lau Angus Z, Tyler Damian J
Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
Department of Physics, University of Oxford, Oxford, UK.
NMR Biomed. 2018 Jun;31(6):e3912. doi: 10.1002/nbm.3912. Epub 2018 Apr 10.
The aim of this work was to investigate the use of C-labelled acetoacetate and β-hydroxybutyrate as novel hyperpolarized substrates in the study of cardiac metabolism. [1- C]Acetoacetate was synthesized by catalysed hydrolysis, and both it and [1- C]β-hydroxybutyrate were hyperpolarized by dissolution dynamic nuclear polarization (DNP). Their metabolism was studied in isolated, perfused rat hearts. Hyperpolarized [1- C]acetoacetate metabolism was also studied in the in vivo rat heart in the fed and fasted states. Hyperpolarization of [1- C]acetoacetate and [1- C]β-hydroxybutyrate provided liquid state polarizations of 8 ± 2% and 3 ± 1%, respectively. The hyperpolarized T values for the two substrates were 28 ± 3 s (acetoacetate) and 20 ± 1 s (β-hydroxybutyrate). Multiple downstream metabolites were observed within the perfused heart, including acetylcarnitine, citrate and glutamate. In the in vivo heart, an increase in acetylcarnitine production from acetoacetate was observed in the fed state, as well as a potential reduction in glutamate. In this work, methods for the generation of hyperpolarized [1- C]acetoacetate and [1- C]β-hydroxybutyrate were investigated, and their metabolism was assessed in both isolated, perfused rat hearts and in the in vivo rat heart. These preliminary investigations show that DNP can be used as an effective in vivo probe of ketone body metabolism in the heart.
这项工作的目的是研究用碳标记的乙酰乙酸盐和β-羟基丁酸盐作为新型超极化底物在心脏代谢研究中的应用。[1-¹³C]乙酰乙酸盐通过催化水解合成，它和[1-¹³C]β-羟基丁酸盐都通过溶解动态核极化（DNP）实现超极化。在离体灌注大鼠心脏中研究了它们的代谢。还在喂食和禁食状态的活体大鼠心脏中研究了超极化[1-¹³C]乙酰乙酸盐的代谢。[1-¹³C]乙酰乙酸盐和[1-¹³C]β-羟基丁酸盐的超极化分别提供了8±2%和3±1%的液态极化。两种底物的超极化T1值分别为28±3秒（乙酰乙酸盐）和20±1秒（β-羟基丁酸盐）。在灌注心脏中观察到多种下游代谢物，包括乙酰肉碱、柠檬酸盐和谷氨酸盐。在活体心脏中，在喂食状态下观察到乙酰乙酸盐产生的乙酰肉碱增加，以及谷氨酸盐可能减少。在这项工作中，研究了生成超极化[1-¹³C]乙酰乙酸盐和[1-¹³C]β-羟基丁酸盐的方法，并在离体灌注大鼠心脏和活体大鼠心脏中评估了它们的代谢。这些初步研究表明，DNP可作为心脏中酮体代谢的有效体内探针。
