Journal:Journal of Burn Care And Research (formerly Journal of Burn Care & Rehabilitation)
Year, Volume, Issue, Page(s):16, 37, 1, 53-63
Study examined skeletal muscle mitochondrial respiratory capacity and function in healthy individuals and in burn victims for up to 2 years postinjury. Muscle biopsies were collected from 16 healthy men and from 69 children with burns encompassing at least 30 percent of their total body surface area. Seventy-nine biopsies were collected from cohorts of burn victims at 2 weeks, 6 months, 12 months, and 24 months postburn. Hypermetabolism was determined by the difference in predicted and measured metabolic rate. Mitochondrial respiration was determined in saponin-permeabilized myofiber bundles. Outcomes were modeled by analysis of variance, with differences in groups assessed by Tukey-adjusted contrasts. Results showed that burn patients were hypermetabolic for up to 2 years postinjury. Coupled mitochondrial respiration was lower at 2 weeks, 6 months, and 12 months postburn compared with healthy controls. Coupled respiration was greater at 6, 12, and 24 months postburn versus 2 weeks postburn. Mitochondrial adenosine diphosphate and oligomycin sensitivity (measures of coupling control) were lower at all time-points postburn vs control, but greater at 6, 12, and 24 months postburn versus 2 weeks postburn. The findings suggest that muscle mitochondrial respiratory capacity remains significantly lower in burn victims for 1-year postinjury. Mitochondrial coupling control is diminished for up to 2 years postinjury in burn victims, resulting in greater mitochondrial thermogenesis. These quantitative and qualitative derangements in skeletal muscle bioenergetics likely contribute to the long-term pathophysiological stress response to burn trauma.