Porter 2014 Am J Physiol
|Porter C, Herndon DN, Børsheim E, Chao T, Reidy P, Borack M, Rasmussen BB, Chondronikola M, Saraf M, Sidossis LS (2014) Uncoupled skeletal muscle mitochondria contribute to hypermetabolism in severely burned adults. Am J Physiol 307:E462-7.|
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 2 separate occasions (11±5 and 21±8 days post injury) from 6 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 when compared to 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.
• Keywords: Burn injury, Skeletal muscle, Mitochondria
Labels: MiParea: Respiration, mt-Medicine Pathology: Other
Organism: Human Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue
Coupling state: LEAK, OXPHOS, ET Pathway: N, NS HRR: Oxygraph-2k