title: Comparison of measuring energy metabolism by different (31) P-magnetic resonance spectroscopy techniques in resting, ischemic, and exercising muscle.
abstract: Alternate methods to quantify mitochondrial activity or function have been extensively used for studying insulin resistance and type 2 diabetes mellitus, namely saturation transfer and phosphocreatine (PCr) recovery. As these methods are in fact determining different parameters, this study aimed to compare saturation transfer results to PCr recovery measurements within the same group. Fifteen subjects underwent saturation transfer and ischemic exercise-recovery experiments. PCr decrease during ischemia (Q), induced by cuff inflation, served as an additional measure of resting ATP (adenosine triphosphate) production. ATP synthetic rate (fATP) measured by saturation transfer (0.234 ± 0.043 mM/s) was greater than (Q = 0.0077 ± 0.0011 mM/s), but correlated well with Q (r = 0.63 P = 0.013). Parameters of PCr recovery correlated well with fATP (Q(max,lin) : r = 0.71, P = 0.003, Q(max,ADP) : r = 0.66, P = 0.007) and Q (Q(max,lin) : r = 0.92, P = 0.000002, Q(max,ADP) : r = 0.76, P = 0.001). In conclusion, although saturation transfer yields higher ATP synthetic rates than PCr decrease during ischemia, their significant correlation indicates that fATP can be used as a marker of mitochondrial activity. The finding that both Q and fATP correlate with PCr recovery kinetics suggests that skeletal muscle with greater maximal aerobic ATP synthetic rates is also metabolically more active at rest. Magn Reson Med, 2011. © 2011 Wiley-Liss, Inc.
authors.affiliation: MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
authors.forename: Albrecht I
authors.initials: AI
authors.lastname: Schmid
authors.forename: Vera B
authors.initials: VB
authors.lastname: Schrauwen-Hinderling
authors.forename: Martin
authors.initials: M
authors.lastname: Andreas
authors.forename: Michael
authors.initials: M
authors.lastname: Wolzt
authors.forename: Ewald
authors.initials: E
authors.lastname: Moser
authors.forename: Michael
authors.initials: M
authors.lastname: Roden
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007511:Ischemia / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism*; D010759:Phosphorus Isotopes
chemical_list: D015415:Biomarkers; D010759:Phosphorus Isotopes; D010725:Phosphocreatine; D000255:Adenosine Triphosphate