Uncoupled skeletal muscle mitochondria contribute to hypermetabolism in severely burned adults.
Am J Physiol Endocrinol Metab
; 307(5): E462-7, 2014 Sep 01.
Article
em En
| MEDLINE
| ID: mdl-25074988
ABSTRACT
Elevated metabolic rate is a hallmark of the stress response to severe burn injury. This response is mediated in part by adrenergic stress and is responsive to changes in ambient temperature. We hypothesize that uncoupling of oxidative phosphorylation in skeletal muscle mitochondria contributes to increased metabolic rate in burn survivors. Here, we determined skeletal muscle mitochondrial function in healthy and severely burned adults. Indirect calorimetry was used to estimate metabolic rate in burn patients. Quadriceps muscle biopsies were collected on two separate occasions (11 ± 5 and 21 ± 8 days postinjury) from six severely burned adults (68 ± 19% of total body surface area burned) and 12 healthy adults. Leak, coupled, and uncoupled mitochondrial respiration was determined in permeabilized myofiber bundles. Metabolic rate was significantly greater than predicted values for burn patients at both time points (P < 0.05). Skeletal muscle oxidative capacity, citrate synthase activity, a marker of mitochondrial abundance, and mitochondrial sensitivity to oligomycin were all lower in burn patients vs. controls at both time points (P < 0.05). A greater proportion of maximal mitochondrial respiration was linked to thermogenesis in burn patients compared with controls (P < 0.05). Increased metabolic rate in severely burned adults is accompanied by derangements in skeletal muscle mitochondrial function. Skeletal muscle mitochondria from burn victims are more uncoupled, indicating greater heat production within skeletal muscle. Our findings suggest that skeletal muscle mitochondrial dysfunction contributes to increased metabolic rate in burn victims.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Queimaduras
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Músculo Esquelético
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Doenças Mitocondriais
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Mitocôndrias Musculares
Tipo de estudo:
Observational_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Adult
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article