title: Skeletal muscle alkaline Pi pool is decreased in overweight-to-obese sedentary subjects and relates to mitochondrial capacity and phosphodiester content.
abstract: 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.
authors.affiliation: 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.|Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia.|Oxford Centre for Clinical MR Research (OCMR), University of Oxford, Oxford, United Kingdom.
authors.forename: Ladislav
authors.initials: L
authors.lastname: Valkovič
authors.affiliation: 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.
authors.forename: Marek
authors.initials: M
authors.lastname: Chmelík
authors.affiliation: Obesity section, Diabetes and Metabolic Disease Laboratory, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia.|Institute of Pathophysiology, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
authors.forename: Barbara
authors.initials: B
authors.lastname: Ukropcová
authors.affiliation: Department of Sports and Physiological Performance, Centre of Sports Science, University of Vienna, Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Heckmann
authors.affiliation: 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.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bogner
authors.affiliation: Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Frollo
authors.affiliation: Department of Sports and Physiological Performance, Centre of Sports Science, University of Vienna, Vienna, Austria.
authors.forename: Harald
authors.initials: H
authors.lastname: Tschan
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Krebs
authors.affiliation: Department of Sports and Physiological Performance, Centre of Sports Science, University of Vienna, Vienna, Austria.
authors.forename: Norbert
authors.initials: N
authors.lastname: Bachl
authors.affiliation: Obesity section, Diabetes and Metabolic Disease Laboratory, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia.
authors.forename: Jozef
authors.initials: J
authors.lastname: Ukropec
authors.affiliation: 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.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Trattnig
authors.affiliation: 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.|Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Krššák
mesh_terms: D000328:Adult; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism*; D050177:Overweight / Q000378:metabolism*; D010710:Phosphates / Q000032:analysis*; D010758:Phosphorus; D057185:Sedentary Behavior
chemical_list: D010710:Phosphates; D010758:Phosphorus
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