title: The effect of branched chain amino acids on skeletal muscle mitochondrial function in young and elderly adults.
abstract: BACKGROUND
  A reduction in maximal mitochondrial ATP production rate (MAPR) and mitochondrial DNA (mtDNA) abundance occurs with age in association with muscle weakness and reduced endurance in elderly people. Branched chain amino acids (BCAA) have been extensively used to improve physical performance.
  
  
  OBJECTIVE
  The objective was to determine whether an 8-h infusion of BCAA enhances MAPR equally in healthy young and elderly adults.
  
  
  METHODS
  Using a crossover study design, we compared the effect BCAA vs. saline infusion in 12 young (23.0 +/- 0.8 yr) and 12 elderly (70.7 +/- 1.1 yr) participants matched for sex and body mass index. Skeletal muscle MAPR and mtDNA abundance were measured in muscle biopsy samples obtained before and at the end of the 8-h infusion.
  
  
  RESULTS
  In young participants, MAPR with the substrates glutamate plus malate (supplying electrons to complex I) and succinate plus rotenone (complex II) increased in response to BCAA infusion, relative to a decline in MAPR in response to the saline infusion. In contrast, MAPR was unaffected by BCAA infusion in the elderly participants. Moreover, mtDNA abundance was lower in the elderly compared with the young participants but was unaffected by the BCAA infusion. Insulin and C-peptide concentrations declined over time during the saline infusion, but these declines were prevented by the BCAA infusion.
  
  
  CONCLUSIONS
  BCAA increased skeletal muscle MAPR in the young participants in comparison with saline, but this effect was not seen in the elderly participants indicating, that unlike in the young, BCAA does not increase muscle mitochondrial function in the elderly.
authors.affiliation: Mayo Clinic, 200 First Street SW, Joseph 5-194, Rochester, Minnesota 55905, USA. nair.sree@mayo.edu
authors.forename: Laura L
authors.initials: LL
authors.lastname: Tatpati
authors.forename: Brian A
authors.initials: BA
authors.lastname: Irving
authors.forename: Andrea
authors.initials: A
authors.lastname: Tom
authors.forename: Maureen L
authors.initials: ML
authors.lastname: Bigelow
authors.forename: Katherine
authors.initials: K
authors.lastname: Klaus
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Short
authors.forename: K Sreekumaran
authors.initials: KS
authors.lastname: Nair
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000597:Amino Acids, Branched-Chain / Q000097:blood / Q000494:pharmacology*; D001786:Blood Glucose / Q000032:analysis; D002096:C-Peptide / Q000032:analysis; D004272:DNA, Mitochondrial / Q000032:analysis; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005934:Glucagon / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008931:Mitochondria, Muscle / Q000187:drug effects* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D055815:Young Adult
chemical_list: D000597:Amino Acids, Branched-Chain; D001786:Blood Glucose; D002096:C-Peptide; D004272:DNA, Mitochondrial; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D000255:Adenosine Triphosphate; D005934:Glucagon