Skeletal muscle metabolism during exercise and recovery in patients with respiratory failure.

Thompson, C.; Davies, Richard; Kemp, Graham J.; Taylor, D. J.; Radda, GK; Rajagopalan, B.

doi:10.1136/thx.48.5.486

Cited by 40 publications

(31 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is noteworthy that the increased ATP cost of contraction observed in the present study is of far greater magnitude than the alterations in the metabolic cost of locomotion (∼ 20-30 %). However, changes of similar magnitude have been reported previously in the plantar flexor muscles of patients with chronic heart failure [39] and COPD (chronic obstructive pulmonary disease) [40,41], which have also been related to whole-body O 2 cost during cycling [42]. When the ATP cost of contraction from the young and old subjects were combined in the present study, we calculated a coefficient of variation of 82 %.…”

Section: Evidence Of An Age-related Increase In the Atp Cost Of Contrsupporting

confidence: 58%

In vivoevidence of an age-related increase in ATP cost of contraction in the plantar flexor muscles

et al. 2013

View full text Add to dashboard Cite

Impaired skeletal muscle efficiency potentially contributes to the age-related decline in exercise capacity and may explain the altered haemodynamic response to exercise in the elderly. Thus we examined whether (i) the ATP cost of contraction increases with age, and (ii) this results in altered convective O(2) delivery to maintain microvascular oxygenation in the calf muscle. To this aim, we used an integrative experimental approach combining (31)P-MRS (magnetic resonance spectroscopy), Doppler ultrasound imaging and NIRS (near-IR spectroscopy) during dynamic plantar flexion exercise at 40% of WR(max) (maximal power output) in 20 healthy young and 20 older subjects matched for physical activity. The ATP cost of contraction was significantly higher in the old (7.2±4.1 mM/min per W) compared with the young (2.4±1.9 mM/min per W; P<0.05) and this was only significantly correlated with the plantar flexion WR(max) value in the old subjects (r=-0.52; P<0.05). Even when differences in power output were taken into account, end-exercise blood flow (old, 259±168 ml/min per W and young, 134±40 ml/min per W; P<0.05) and convective O(2) delivery (old, 0.048±0.031 l/min per W and young, 0.026±0.008 l/min per W; P<0.05) were greater in the old in comparison with the young subjects. In contrast, the NIRS oxyhaemoglobin, deoxyhaemoglobin and microvascular oxygenation indices were not significantly different between the groups (P>0.05). Therefore the present study reveals that, although the peripheral haemodynamic responses to plantar flexion exercise appear to be appropriate, the elevated energy cost of contraction and associated reduction in the WR(max) value in this muscle group may play a role in limiting exercise capacity with age.

show abstract

Section: Evidence Of An Age-related Increase In the Atp Cost Of Contrsupporting

confidence: 58%

In vivoevidence of an age-related increase in ATP cost of contraction in the plantar flexor muscles

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The ratio of PCr (phosphocreatine) to P i is closely related to that of ATP to ADP and, hence, is a useful marker of muscle energy status. The PCr/P i ratio is significantly lower [47] during exercise in COPD patients, with faster PCr depletion [48], and post-exercise recovery is slower in patients compared with healthy controls. Gosker et al [49] have also demonstrated significantly reduced levels of UCP-3 (uncoupling protein-3) (implicated in the regulation of energy metabolism) in vastus lateralis muscle biopsies of COPD patients [49].…”

Section: Muscle Disease In Copd: Laboratory Observationsmentioning

confidence: 99%

Skeletal muscle dysfunction in COPD: clinical and laboratory observations

et al. 2009

View full text Add to dashboard Cite

COPD (chronic obstructive pulmonary disease), although primarily a disease of the lungs, exhibits secondary systemic manifestations. The skeletal muscles are of particular interest because their function (or dysfunction) not only influences the symptoms that limit exercise, but may contribute directly to poor exercise performance. Furthermore, skeletal muscle weakness is of great clinical importance in COPD as it is recognized to contribute independently to poor health status, increased healthcare utilization and even mortality. The present review describes the current knowledge of the structural and functional abnormalities of skeletal muscles in COPD and the possible aetiological factors. Increasing knowledge of the molecular pathways of muscle wasting will lead to the development of new therapeutic agents and strategies to combat COPD muscle dysfunction.

show abstract

“…Given the reduced oxidative capacity of these fibers (17) and the reduction in maximal activity of some enzymes involved in Krebs cycle in patients with COPD (13,18), it has been suggested that the relative contribution of oxidative and anaerobic metabolism during exercise may be altered in patients with COPD (30). However, an issue that has probably magnified the difference between patients and controls is the starkly contrasting activity levels between such groups (31).…”

mentioning

confidence: 90%

Evidence that a higher ATP cost of muscular contraction contributes to the lower mechanical efficiency associated with COPD: preliminary findings

Layec

Haseler

Hoff

et al. 2011

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

Layec G, Haseler LJ, Hoff J, Richardson RS. Evidence that a higher ATP cost of muscular contraction contributes to the lower mechanical efficiency associated with COPD: preliminary findings. Am J Physiol Regul Integr Comp Physiol 300: R1142-R1147, 2011. First published February 9, 2011 doi:10.1152/ajpregu.00835.2010.-Impaired metabolism in peripheral skeletal muscles potentially contributes to exercise intolerance in chronic obstructive pulmonary disease (COPD). We used 31 P-magnetic resonance spectroscopy ( 31 P-MRS) to examine the energy cost and skeletal muscle energetics in six patients with COPD during dynamic plantar flexion exercise compared with six well-matched healthy control subjects. Patients with COPD displayed a higher energy cost of muscle contraction compared with the controls (control: 6.1 Ϯ 3.1% of rest·min Ϫ1 ·W Ϫ1 , COPD: 13.6 Ϯ 8.3% of rest·min Ϫ1 ·W Ϫ1 , P ϭ 0.01). Although, the initial phosphocreatine resynthesis rate was also significantly attenuated in patients with COPD compared with controls (control: 74 Ϯ 17% of rest/min, COPD: 52 Ϯ 13% of rest/min, P ϭ 0.04), when scaled to power output, oxidative ATP synthesis was similar between groups (6.5 Ϯ 2.3% of rest·min Ϫ1 ·W Ϫ1 in control and 7.8 Ϯ 3.9% of rest·min Ϫ1 ·W Ϫ1 in COPD, P ϭ 0.52). Therefore, our results reveal, for the first time that in a small subset of patients with COPD a higher ATP cost of muscle contraction may substantially contribute to the lower mechanical efficiency previously reported in this population. In addition, it appears that some patients with COPD have preserved mitochondrial function and normal energy supply in lower limb skeletal muscle. 31 P-MRS; muscle metabolism; exercise; mitochondrial function LIMITED EXERCISE CAPACITY not only plays a central role in the life of patients with chronic obstructive pulmonary disease (COPD), but also acts both as a marker of well-being and a prognostic tool. Given that COPD is a disease of the lung, it has long been proposed that the inability to sustain a high level of ventilation was the main factor that limited exercise performance in these patients (3). However, as leg discomfort was a frequent exercise-limiting symptom invoked by patients with COPD during cycling exercise (15), peripheral muscle dysfunction has also been implicated (19). To date, the mechanistic basis for this exercise intolerance is still unresolved (6, 22), although a decrease in muscle strength and endurance along with reduced capillarization, percentage of oxidative fibers, and a reduced activity of different oxidative enzymes measured in vitro may play a role.These biochemical and histochemical changes observed in the peripheral skeletal muscle of patients with COPD (32) likely alter muscle energy production during exercise and recovery, which may, in turn, affect exercise capacity. Previously, a decreased mechanical efficiency (the chemical conversion of energy to mechanical work) has been reported in a small subset of patients with COPD (1, 25). In these studies, such a decrease in mechanical...

show abstract

Skeletal muscle metabolism during exercise and recovery in patients with respiratory failure.

Cited by 40 publications

References 26 publications

In vivoevidence of an age-related increase in ATP cost of contraction in the plantar flexor muscles

In vivoevidence of an age-related increase in ATP cost of contraction in the plantar flexor muscles

Skeletal muscle dysfunction in COPD: clinical and laboratory observations

Evidence that a higher ATP cost of muscular contraction contributes to the lower mechanical efficiency associated with COPD: preliminary findings

Contact Info

Product

Resources

About