Skeletal Muscle Protein Breakdown Remains Elevated in Pediatric Burn Survivors up to One-Year Post-Injury.
Acute alterations in skeletal muscle protein metabolism are a well-established event associated with the stress response to burns. Nevertheless, the long-lasting effects of burn injury on skeletal muscle protein turnover are incompletely understood. This study was undertaken to investigate fractional synthesis (FSR) and breakdown (FBR) rates of protein in skeletal muscle of pediatric burn patients (n  =  42, >30% total body surface area burns) for up to 1 year after injury. Skeletal muscle protein kinetics were measured in the post-prandial state following bolus injections of C6 and N phenylalanine stable isotopes. Plasma and muscle phenylalanine enrichments were quantified using gas chromatography-mass spectrometry. We found that the FSR in burn patients was 2- to 3-fold higher than values from healthy men previously reported in the literature (P ≤ 0.05). The FBR was 4- to 6-fold higher than healthy values (P  <  0.01). Therefore, net protein balance was lower in burn patients compared with healthy men from 2 weeks to 12 months post-injury (P  <  0.05). These findings show that skeletal muscle protein turnover stays elevated for up to 1 year after burn, an effect attributable to simultaneous increases in FBR and FSR. Muscle FBR exceeds FSR during this time, producing a persistent negative net protein balance, even in the post-prandial state, which likely contributes to the prolonged cachexia seen in burned victims.
*Metabolism Unit, Shriners Hospitals for Children †Division of Rehabilitation Sciences, Department of Preventive Medicine and Community Health ‡Department of Surgery, University of Texas Medical Branch, Galveston, Texas §Department of Nutrition and Dietetics, Harokopio University of Athens, Athens, Greece ¶Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas.
Tony
T
Chao
David N
DN
Herndon
Craig
C
Porter
Maria
M
Chondronikola
Anastasia
A
Chaidemenou
Doaa Reda
DR
Abdelrahman
Fredrick J
FJ
Bohanon
Clark
C
Andersen
Labros S
LS
Sidossis
D000293:Adolescent; D002056:Burns / Q000378:metabolism* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D018529:Nutritional Support / Q000379:methods; D017741:Survivors
D009124:Muscle Proteins