title: Adult patients are more catabolic than children during acute phase after burn injury: a retrospective analysis on muscle protein kinetics.
abstract: OBJECTIVE
  This study was performed to determine if there is an age-related specificity in the response of muscle protein metabolism to severe burn injury during acute hospitalization. This is a retrospective analysis of previously published data.
  
  
  METHODS
  Nineteen adult and 58 pediatric burn-injured patients (age 43.3 ± 14.3 vs. 7.2 ± 5.3 years, adult vs. children) participated in stable isotope [ring-(2)H(5)]phenylalanine (Phe) infusion studies. Femoral arterial and venous blood samples and muscle biopsy samples were collected throughout the study. Data are presented as means ± standard deviation (SD). A p value less than 0.05 was considered statistically significant.
  
  
  RESULTS
  Muscle net protein balance (NB) was higher in children (adult vs. children, -43 ± 61 vs. 8 ± 68 nmol Phe/min/100 ml leg volume, p < 0.05). Muscle protein fractional synthesis rate (FSR) was higher in children (adult vs. children, 0.11 ± 0.05 vs. 0.16 ± 0.10 %/h, p < 0.05). Leg muscle protein breakdown was not different between the groups (adult vs. children, 179 ± 115 vs. 184 ± 124 nmol Phe/min/100 ml leg volume, p > 0.05); synthesis rate was 134 ± 96 and 192 ± 128 nmol Phe/min/100 ml leg volume in adults and children, respectively (p = 0.07). Age significantly correlated with muscle protein NB (p = 0.01) and FSR (p = 0.02); but not with breakdown (p = 0.67) and synthesis (p = 0.07) rates measured by using a three-pool model.
  
  
  CONCLUSIONS
  In burn injury, the muscle protein breakdown may be affected to the same extent in adults and children, whereas synthesis may have age-related specificities, resulting in a better but still low NB in children.
authors.affiliation: Department of Surgery, Metabolism Unit, Shriners Hospital for Children, University of Texas Medical Branch, 815 Market Street, Galveston, TX 77555-1220, USA.
authors.forename: Demidmaa
authors.initials: D
authors.lastname: Tuvdendorj
authors.forename: David L
authors.initials: DL
authors.lastname: Chinkes
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Zhang
authors.forename: Arny A
authors.initials: AA
authors.lastname: Ferrando
authors.forename: Itoro E
authors.initials: IE
authors.lastname: Elijah
authors.forename: Ronald P
authors.initials: RP
authors.lastname: Mlcak
authors.forename: Celeste C
authors.initials: CC
authors.lastname: Finnerty
authors.forename: Robert R
authors.initials: RR
authors.lastname: Wolfe
authors.forename: David N
authors.initials: DN
authors.lastname: Herndon
mesh_terms: D000328:Adult; D000367:Age Factors; D002056:Burns / Q000097:blood / Q000378:metabolism*; D002648:Child; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism*; D012189:Retrospective Studies
chemical_list: D009124:Muscle Proteins