Skeletal muscle is anabolically unresponsive to an amino acid infusion in pediatric burn patients 6 months postinjury.
OBJECTIVE
To evaluate leg muscle, whole-body muscle, and whole-body nonmuscle protein response to anabolic signaling of amino acids in pediatric burn patients at 6 months after injury.


BACKGROUND
Burn injury is associated with a catabolic state persisting years after the injury. The tissue response to nutritional signaling (eg, amino acids) plays a critical role in tissue protein net balance via coordination of protein synthesis and breakdown mechanisms.


METHODS
A total of 10 patients (7.4 ± 3.8 years; 27.4 ± 14.7 kg) and 5 healthy young males (22 ± 3 years; 76 ± 15 kg) underwent an 8-hour stable isotope infusion study. During the last 3 hours, an amino acid solution (10% Travasol, Clintec Nutrition, Deerfield, IL) was infused. Femoral arterial and venous blood samples and muscle biopsy samples were collected throughout the study. A P value of less than 0.05 was considered statistically different.


RESULTS
During amino acid infusion, leg muscle protein synthesis rate significantly increased (P < 0.05) in both groups, however, in the burn group, protein breakdown also increased, although nonsignificantly. As a result, protein net balance remained negative. In the control group, breakdown nonsignificantly decreased resulting in a significant increase (P < 0.05) in muscle protein net balance. Whole-body protein breakdown was significantly higher in the burn patients.


CONCLUSIONS
In pediatric burn patients at 6 months postinjury, leg muscle protein net deposition is unresponsive to amino acid infusion; and whole-body protein breakdown is significantly higher than in the control group.
Department of Surgery, University of Texas Medical Branch Galveston, TX, USA.
Demidmaa
D
Tuvdendorj
David L
DL
Chinkes
Xiao-Jun
XJ
Zhang
Melinda
M
Sheffield-Moore
David N
DN
Herndon
D000596:Amino Acids / Q000008:administration & dosage*; D001706:Biopsy; D002056:Burns / Q000503:physiopathology* / Q000628:therapy*; D002648:Child; D002675:Child, Preschool; D004573:Electrolytes / Q000008:administration & dosage*; D005260:Female; D005947:Glucose / Q000008:administration & dosage*; D006801:Humans; D007553:Isotope Labeling; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology*; D009133:Muscular Atrophy / Q000503:physiopathology; D057947:Parenteral Nutrition Solutions; D012016:Reference Values; D012996:Solutions / Q000008:administration & dosage; D055815:Young Adult
D000596:Amino Acids; D004573:Electrolytes; D009124:Muscle Proteins; D057947:Parenteral Nutrition Solutions; D012996:Solutions; C545824:amino-acid, glucose, and electrolyte solution; D005947:Glucose
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