期刊
AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM
卷 311, 期 2, 页码 E358-E366出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpendo.00028.2016
关键词
mitochondrial capacity assessment; State 3 respiration; respirometry; PCr recovery
资金
- Flight Attendant Medical Research Institute (FAMRI)
- NIH National Heart, Lung, and Blood Institute [K99 HL-125756, PO1 HL-091830]
- Veteran's Administration Rehabilitation Research and Development Service [E6910-R, E1697-R, E1433-P, E9275-L]
Although theoretically sound, the accuracy and precision of P-31-magnetic resonance spectroscopy (P-31-MRS) approaches to quantitatively estimate mitochondrial capacity are not well documented. Therefore, employing four differing models of respiratory control [linear, kinetic, and multipoint adenosine diphosphate (ADP) and phosphorylation potential], this study sought to determine the accuracy and precision of P-31-MRS assessments of peak mitochondrial adenosine-triphosphate (ATP) synthesis rate utilizing directly measured peak respiration (State 3) in permeabilized skeletal muscle fibers. In 23 subjects of different fitness levels, P-31-MRS during a 24-s maximal isometric knee extension and high-resolution respirometry in muscle fibers from the vastus lateralis was performed. Although significantly correlated with State 3 respiration (r = 0.72), both the linear (45 +/- 13 mM/min) and phosphorylation potential (47 +/- 16 mM/min) models grossly overestimated the calculated in vitro peak ATP synthesis rate (P < 0.05). Of the ADP models, the kinetic model was well correlated with State 3 respiration (r = 0.72, P < 0.05), but moderately overestimated ATP synthesis rate (P < 0.05), while the multipoint model, although being somewhat less well correlated with State 3 respiration (r = 0.55, P < 0.05), most accurately reflected peak ATP synthesis rate. Of note, the PCr recovery time constant (tau), a qualitative index of mitochondrial capacity, exhibited the strongest correlation with State 3 respiration (r = 0.80, P < 0.05). Therefore, this study reveals that each of the P-31-MRS data analyses, including PCr tau, exhibit precision in terms of mitochondrial capacity. As only the multipoint ADP model did not overstimate the peak skeletal muscle mitochondrial ATP synthesis, the multipoint ADP model is the only quantitative approach to exhibit both accuracy and precision.
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