Valkovič Ladislav, Chmelík Marek, Ukropcová Barbara, Heckmann Thomas, Bogner Wolfgang, Frollo Ivan, Tschan Harald, Krebs Michael, Bachl Norbert, Ukropec Jozef, Trattnig Siegfried, Krššák Martin
High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria.
Sci Rep. 2016 Feb 3;6:20087. doi: 10.1038/srep20087.
Defects in skeletal muscle energy metabolism are indicative of systemic disorders such as obesity or type 2 diabetes. Phosphorus magnetic resonance spectroscopy ((31)P-MRS), in particularly dynamic (31)P-MRS, provides a powerful tool for the non-invasive investigation of muscular oxidative metabolism. The increase in spectral and temporal resolution of (31)P-MRS at ultra high fields (i.e., 7T) uncovers new potential for previously implemented techniques, e.g., saturation transfer (ST) or highly resolved static spectra. In this study, we aimed to investigate the differences in muscle metabolism between overweight-to-obese sedentary (Ob/Sed) and lean active (L/Ac) individuals through dynamic, static, and ST (31)P-MRS at 7T. In addition, as the dynamic (31)P-MRS requires a complex setup and patient exercise, our aim was to identify an alternative technique that might provide a biomarker of oxidative metabolism. The Ob/Sed group exhibited lower mitochondrial capacity, and, in addition, static (31)P-MRS also revealed differences in the Pi-to-ATP exchange flux, the alkaline Pi-pool, and glycero-phosphocholine concentrations between the groups. In addition to these differences, we have identified correlations between dynamically measured oxidative flux and static concentrations of the alkaline Pi-pool and glycero-phosphocholine, suggesting the possibility of using high spectral resolution (31)P-MRS data, acquired at rest, as a marker of oxidative metabolism.
骨骼肌能量代谢缺陷表明存在肥胖或2型糖尿病等全身性疾病。磷磁共振波谱（（31）P-MRS），尤其是动态（31）P-MRS，为肌肉氧化代谢的无创研究提供了有力工具。超高场（即7T）下（31）P-MRS的光谱和时间分辨率提高，揭示了先前实施技术（如饱和转移（ST）或高分辨率静态光谱）的新潜力。在本研究中，我们旨在通过7T下的动态、静态和ST（31）P-MRS研究超重至肥胖久坐不动（Ob/Sed）和瘦且活跃（L/Ac）个体之间肌肉代谢的差异。此外，由于动态（31）P-MRS需要复杂的设置和患者运动，我们的目标是确定一种可能提供氧化代谢生物标志物的替代技术。Ob/Sed组的线粒体容量较低，此外，静态（31）P-MRS还揭示了两组之间无机磷（Pi）与三磷酸腺苷（ATP）交换通量、碱性Pi池和甘油磷酸胆碱浓度的差异。除了这些差异，我们还发现动态测量的氧化通量与碱性Pi池和甘油磷酸胆碱的静态浓度之间存在相关性，这表明有可能将静息时获得的高光谱分辨率（31）P-MRS数据用作氧化代谢的标志物。
