Aerobic exercise and muscle metabolism in patients with mitochondrial myopathy

Trenell, Michael I.; Sue, Carolyn M.; Kemp, Graham J.; Sachinwalla, Toos; Thompson, Campbell

doi:10.1002/mus.20484

Cited by 60 publications

(67 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…To improve the precision of this measurement, we used a modified version of this calculation (88) in which the total proton disappearance (i.e. Edt) was estimated cumulatively from the start of recovery, and then fitted to an exponential function to obtain the initial recovery rate V eff .…”

Section: Resultsmentioning

confidence: 99%

Comparative determination of energy production rates and mitochondrial function using different ³¹P MRS quantitative methods in sedentary and trained subjects

Layec

Bringard²,

Fur

et al. 2010

NMR in Biomedicine

View full text Add to dashboard Cite

Muscle energetics has been largely and quantitatively investigated using (31)P MRS. Various methods have been used to estimate the corresponding rate of oxidative ATP synthesis (ATP(ox)); however, potential differences among methods have not been investigated. In this study, we aimed to compare the rates of ATP production and energy cost in two groups of subjects with different training status using four different methods: indirect method (method 1), ADP control model (method 2) and phosphate potential control model (method 3). Method 4 was a modified version of method 3 with the introduction of a correction factor allowing for similar values to be obtained for the end-exercise oxidative ATP synthesis rate inferred from exercise measurements and the initial recovery phosphocreatine resynthesis rate. Seven sedentary and seven endurance-trained subjects performed a dynamic standardised rest-exercise-recovery protocol. We quantified the rates of ATP(ox) and anaerobic ATP synthesis (ATP(ana)) using (31)P MRS data recorded at 1.5 T. The rates of ATP(ox) over the entire exercise session were independent of the method used, except for method 4 which provided significantly higher values in both groups (p < 0.01). In addition, methods 1-3 were cross-correlated, thereby confirming their statistical agreement. The rate of ATP(ana) was significantly higher with method 1 (p < 0.01) and lower with method 4 (p < 0.01). As a result of the higher rate of ATP(ox), EC (method 4) calculated over the entire exercise session was higher and initial EC (method 1) was lower in both groups compared with the other methods. We showed in this study that the rate of ATP(ox) was independent of the calculation method, as long as no corrections (method 4) were performed. In contrast, results related to the rates of ATP(ana) were strongly affected by the calculation method and, more exactly, by the estimation of protons generated by ATP(ox). Although the absolute EC values differed between the methods, within- or between-subject comparisons are still valid given the tight relationships between them.

show abstract

Section: Resultsmentioning

confidence: 99%

Comparative determination of energy production rates and mitochondrial function using different ³¹P MRS quantitative methods in sedentary and trained subjects

Layec

Bringard²,

Fur

et al. 2010

NMR in Biomedicine

View full text Add to dashboard Cite

show abstract

“…This is large even by the standards of e.g. primary mitochondrial disease (Trenell et al 2006), mitochondrial dysfunction secondary to peripheral vascular disease (Kemp et al 2001a). …”

Section: Discussionmentioning

confidence: 99%

Cytosolic pH buffering during exercise and recovery in skeletal muscle of patients with McArdle’s disease

et al. 2008

Self Cite

View full text Add to dashboard Cite

Cellular pH control is important in muscle physiology, and for interpretation of (31)P magnetic resonance spectroscopy (MRS) data. Cellular acidification in exercise results from coupled glycolytic ATP production mitigated by cytosolic buffering, 'consumption' of H(+) by phosphocreatine (PCr) breakdown, and membrane transport processes. Ex vivo methods for cytosolic buffer capacity are vulnerable to artefact, and MRS methods often require assumptions. (31)P MRS of early exercise, when pH increases unopposed by glycolysis, is conceptually simple, but limited in normal muscle by time resolution and signal-to-noise. A therapeutic trial (Martinuzzi A et al. Musc Nerve 37: 350-357, 2007) in McArdle's disease (glycogen phosphorylase deficiency), where pH does not decrease with exercise, offered the opportunity to test (31)P MRS data obtained throughout incremental plantar flexion exercise and recovery in ten McArdle's patients against the simple model of cellular pH control. Changes in pH, [Pi] and [PCr] throughout exercise and recovery were quantitatively consistent with mean +/- SEM buffer capacity of 10 +/- 1 mM/(pH unit), which was not significantly different from the control subjects under the initial-exercise conditions where the comparison could be made. The simple model of cellular acid-base balance therefore gives an adequate account of cellular pH changes during both exercise and recovery in McArdle's disease.

show abstract

“…Due to the rapid sampling time, we eliminated the three first partially relaxed spectra for which the relaxation factors were different from the others. Changes in pH and in the concentration of phosphorus metabolites during contraction and recovery phases were used in order to calculate oxidative capacity and the rates of ATP synthesis through the creatine kinase reaction, oxidative phosphorylation, and anaerobic glycolysis as previously described (Conley et al 1997;Trenell et al 2006) and detailed in the ''Appendix''.…”

Section: P-mrsmentioning

confidence: 99%

Does oxidative capacity affect energy cost? An in vivo MR investigation of skeletal muscle energetics

Layec

Bringard²,

Vilmen

et al. 2009

Eur J Appl Physiol

View full text Add to dashboard Cite

Investigations of training effects on exercise energy cost have yielded conflicting results. The purpose of the present study was to compare quadriceps energy cost and oxidative capacity between endurance-trained and sedentary subjects during a heavy dynamic knee extension exercise. We quantified the rates of ATP turnover from oxidative and anaerobic pathways with (31)P-MRS, and we measured simultaneously pulmonary oxygen uptake in order to assess both total ATP production [i.e., energy cost (EC)] and O(2) consumption (O(2) cost) scaled to power output. Seven sedentary (SED) and seven endurance-trained (TRA) subjects performed a dynamic standardized rest-exercise-recovery protocol at an exercise intensity corresponding to 35% of maximal voluntary contraction. We showed that during a dynamic heavy exercise, the O(2) cost and EC were similar in the SED and endurance-trained groups. For a given EC, endurance-trained subjects exhibited a higher relative mitochondrial contribution to ATP production at the muscle level (84 +/- 12% in TRA and 57 +/- 12% in SED; P < 0.01) whereas the anaerobic contribution was reduced (18 +/- 12% in TRA and 44 +/- 11% in SED; P < 0.01). Our results obtained in vivo illustrate that on the one hand the beneficial effects of endurance training are not related to any reduction in EC or O(2) cost and on the other hand that this similar EC was linked to a change regarding the contribution of anaerobic and oxidative processes to energy production, i.e., a greater aerobic energy contribution associated with a concomitant reduction of the anaerobic energy supply.

show abstract

Aerobic exercise and muscle metabolism in patients with mitochondrial myopathy

Cited by 60 publications

References 33 publications

Comparative determination of energy production rates and mitochondrial function using different ³¹P MRS quantitative methods in sedentary and trained subjects

Comparative determination of energy production rates and mitochondrial function using different ³¹P MRS quantitative methods in sedentary and trained subjects

Cytosolic pH buffering during exercise and recovery in skeletal muscle of patients with McArdle’s disease

Does oxidative capacity affect energy cost? An in vivo MR investigation of skeletal muscle energetics

Contact Info

Product

Resources

About

Aerobic exercise and muscle metabolism in patients with mitochondrial myopathy

Cited by 60 publications

References 33 publications

Comparative determination of energy production rates and mitochondrial function using different 31P MRS quantitative methods in sedentary and trained subjects

Comparative determination of energy production rates and mitochondrial function using different 31P MRS quantitative methods in sedentary and trained subjects

Cytosolic pH buffering during exercise and recovery in skeletal muscle of patients with McArdle’s disease

Does oxidative capacity affect energy cost? An in vivo MR investigation of skeletal muscle energetics

Contact Info

Product

Resources

About

Comparative determination of energy production rates and mitochondrial function using different ³¹P MRS quantitative methods in sedentary and trained subjects

Comparative determination of energy production rates and mitochondrial function using different ³¹P MRS quantitative methods in sedentary and trained subjects