Skeletal muscle reoxygenation after high-intensity exercise in mitochondrial myopathy

Skeletal muscle reoxygenation after high-intensity exercise in mitochondrial myopathy

Author Bravo, Daniela M. Autor UNIFESP Google Scholar
Gimenes, Ana Cristina Autor UNIFESP Google Scholar
Nascimento, Rubia B. Autor UNIFESP Google Scholar
Ferreira, Eloara V. M. Autor UNIFESP Google Scholar
Siqueira, Ana Cristina B. Autor UNIFESP Google Scholar
Meda, Ethiane D. S. Autor UNIFESP Google Scholar
Neder, J. Alberto Autor UNIFESP Google Scholar
Nery, Luiz Eduardo Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract This study addressed whether O-2 delivery during recovery from high-intensity, supra-gas exchange threshold exercise would be matched to O-2 utilization at the microvascular level in patients with mitochondrial myopathy (MM). Off-exercise kinetics of (1) pulmonary O-2 uptake (V) over dotO(2p)); (2) an index of fractional O-2 extraction by near-infrared spectroscopy (Delta[deoxy-Hb + Mb]) in the vastus lateralis and (3) cardiac output (Q'(T)) by impedance cardiography were assessed in 12 patients with biopsy-proven MM (chronic progressive external ophthalmoplegia) and 12 age-and gender-matched controls. Kinetics of (V) over dotO(2p) were significantly slower in patients than controls (tau = 53.8 +/- 16.5 vs. 38.8 +/- 7.6 s, respectively; p < 0.05). Q'(T)0, however, declined at similar rates (s = 64.7 +/- 18.8 vs. 73.0 +/- 21.6 s; p > 0.05) being typically slower than (V) over dotO(2p) in both groups. Importantly, Delta[deoxy-Hb + Mb] dynamics (MRT) were equal to, or faster than, tau(V) over dotO(2p) in patients and controls, respectively. in fact, there were no between-group differences in tau(V) over dotO(2p)/MRTD[deoxy-Hb + Mb] (1.1 +/- 0.4 vs. 1.0 +/- 0.2, p > 0.05) thereby indicating similar rates of microvascular O-2 delivery. These data indicate that the slower rate of recovery of muscle metabolism after highintensity exercise is not related to impaired microvascular O-2 delivery in patients with MM. This phenomenon, therefore, seems to reflect the intra-myocyte abnormalities that characterize this patient population.
Keywords Mitochondrial myopathy
Oxygen uptake
Exercise recovery
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Date 2012-05-01
Published in European Journal of Applied Physiology. New York: Springer, v. 112, n. 5, p. 1763-1771, 2012.
ISSN 1439-6319 (Sherpa/Romeo, impact factor)
Publisher Springer
Extent 1763-1771
Access rights Closed access
Type Article
Web of Science ID WOS:000302745700020

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