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Layec 2016 Am J Physiol Endocrinol Metab

From Bioblast
Publications in the MiPMap
Layec G, Gifford JR, Trinity JD, Hart CR, Garten RS, Park SY, Le Fur Y, Jeong EK, Richardson RS (2016) Accuracy and precision of quantitative 31P-MRS measurements of human skeletal muscle mitochondrial function. Am J Physiol Endocrinol Metab 311:E358-66.

ยป PMID: 27302751

Layec G, Gifford JR, Trinity JD, Hart CR, Garten RS, Park SY, Le Fur Y, Jeong EK, Richardson RS (2016) Am J Physiol Endocrinol Metab

Abstract: Although theoretically sound, the accuracy and precision of (31)P-magnetic resonance spectroscopy ((31)P-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 (31)P-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, (31)P-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 ยฑ 13 mM/min) and phosphorylation potential (47 ยฑ 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 (ฯ„), 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 (31)P-MRS data analyses, including PCr ฯ„, 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. โ€ข Keywords: PCr recovery, State 3 respiration, Mitochondrial capacity assessment, Respirometry


Labels: MiParea: Respiration, Exercise physiology;nutrition;life style 


Organism: Human  Tissue;cell: Skeletal muscle  Preparation: Permeabilized tissue 

Regulation: ADP, ATP, ATP production  Coupling state: LEAK, OXPHOS  Pathway: N, NS 


2016-08