A 1H-NMR approach to myocardial energetics

Abstract

Understanding the energetic state of the heart is essential for unraveling the central tenets of cardiac physiology. The heart uses a tremendous amount of energy and reductions in that energy supply can have lethal consequences. While ischemic events clearly result in significant metabolic perturbations, heart failure with both preserved and reduced ejection fraction display reductions in energetic status. To date, most cardiac energetics have been performed using 31P-NMR, which requires dedicated access to a specialized NMR spectrometer. This has limited the availability of this method to a handful of centers around the world. Here we present a method of assessing myocardial energetics in the isolated mouse heart using 1H-NMR spectrometers that are widely available in NMR core facilities. In addition, this methodology provides information on many other important metabolites within the heart, including unique metabolic differences between the hypoxic and ischemic hearts. Furthermore, we demonstrate the correlation between myocardial energetics and measures of contractile function in the mouse heart. These methods will allow a broader examination of myocardial energetics providing a valuable tool to aid in the understanding of the nature of these energetic deficits and to develop therapies directed at improving myocardial energetics in failing hearts.

PK11195 Protects From Cell Death Only When Applied During Reperfusion: Succinate-Mediated Mechanism of Action

“…To summarize, our cellular model of simulated ischemia and reperfusion revealed changes in cardiac glucose, amino acids, and fatty acid metabolism similar to that reported in human (Fillmore et al, 2014;Yehualashet et al, 2020) and animal models (Masoud et al, 2014;Heitzman et al, 2020) of ischemia and reperfusion. We found a significant increase in succinate and glycogen utilization during reperfusion which was reversed by PK11195.…”

Intracellular Fate of the Photosensitizer Chlorin e4 with Different Carriers and Induced Metabolic Changes Studied by 1H NMR Spectroscopy

“…In addition, there is a pronounced pH dependence in the chemical shifts of adenine-derived nucleotides (AXP), as previously discussed [53]. In the current study, AXP, most likely AMP [53,60], and UMP were only observed in the spectra of samples treated with Ce4. Furthermore, among the compounds listed in Table 2, some were only detectable in the presence of KP or without applying a T 2 filter (see Section 3.3 below).…”

1H HR-MAS NMR Based Metabolic Profiling of Lung Cancer Cells with Induced and De-Induced Cisplatin Resistance to Reveal Metabolic Resistance Adaptations

“…The unambiguous assignment of resonances to nucleotides and nucleosides, in particular to those derived from purine bases with two non-coupling singlets in the downfield spectral region, can be challenging. Their chemical shift values are in part difficult to distinguish (e.g., Ino/Ade) [17], are very pH-sensitive and often overlap for mono-, di-and triphosphates [18,19]. However, the resonance at 8.6 ppm labeled AXP most likely derives from AMP, since the adenine H-2-resonance of AMP separates quite well from that of ADP/ATP at neutral pH [18].…”

“…Their chemical shift values are in part difficult to distinguish (e.g., Ino/Ade) [17], are very pH-sensitive and often overlap for mono-, di-and triphosphates [18,19]. However, the resonance at 8.6 ppm labeled AXP most likely derives from AMP, since the adenine H-2-resonance of AMP separates quite well from that of ADP/ATP at neutral pH [18]. Most of the metabolites identified in the A24 cells have also been described in HR-MAS NMR spectra of lung cancer tissue [17,20].…”