title: Hydrolyzed casein and whey protein meals comparably stimulate net whole-body protein synthesis in COPD patients with nutritional depletion without an additional effect of leucine co-ingestion.
abstract: OBJECTIVE
  Muscle wasting commonly occurs in COPD, negatively affecting outcome. The aim was to examine the net whole-body protein synthesis response to two milk protein meals with comparable absorption rates (hydrolyzed casein (hCAS) vs. hydrolyzed whey (hWHEY)) and the effects of co-ingesting leucine.
  
  
  METHODS
  Twelve COPD patients (GOLD stage II-IV) with nutritional depletion, were studied following intake of a 15 g hCAS or hWHEY protein meal with or without leucine-co-ingestion, according to a double-blind randomized cross-over design. The isotopic tracers L-[ring-(2)H5]-Phenylalanine, L-[ring-(2)H2]-Tyrosine, L-[(2)H3]-3-Methylhistidine (given via continuous intravenous infusion), and L-[(15)N]-Phenylalanine (added to the protein meals) were used to measure endogenous whole-body protein breakdown (WbPB), whole-body protein synthesis (WbPS), net protein synthesis (NetPS), splanchnic extraction and myofibrillar protein breakdown (MPB). Analyses were done in arterialized-venous plasma by LC/MS/MS.
  
  
  RESULTS
  WbPS was greater after intake of the hCAS protein meal (P < 0.05) whereas the hWHEY protein meal reduced WbPB more (P < 0.01). NetPS was stimulated comparably, with a protein conversion rate greater than 70%. Addition of leucine did not modify the insulin, WbPB, WbPS or MPB response.
  
  
  CONCLUSIONS
  Hydrolyzed casein and whey protein meals comparably and efficiently stimulate whole-body protein anabolism in COPD patients with nutritional depletion without an additional effect of leucine co-ingestion. This trial was registered at clinicaltrials.gov as NCT01154400.
authors.affiliation: Center for Translational Research in Aging & Longevity, Dept. of Health and Kinesiology, Texas A&M University, College Station, TX, USA; Center for Translational Research in Aging & Longevity, Dept. of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA. Electronic address: r.jonker@ctral.org.
authors.forename: Renate
authors.initials: R
authors.lastname: Jonker
authors.affiliation: Center for Translational Research in Aging & Longevity, Dept. of Health and Kinesiology, Texas A&M University, College Station, TX, USA; Center for Translational Research in Aging & Longevity, Dept. of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Nicolaas E P
authors.initials: NE
authors.lastname: Deutz
authors.affiliation: Dept. of Pulmonary and Critical Care Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Marcia L
authors.initials: ML
authors.lastname: Erbland
authors.affiliation: Dept. of Pulmonary and Critical Care Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Anderson
authors.affiliation: Center for Translational Research in Aging & Longevity, Dept. of Health and Kinesiology, Texas A&M University, College Station, TX, USA; Center for Translational Research in Aging & Longevity, Dept. of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Mariëlle P K J
authors.initials: MP
authors.lastname: Engelen
mesh_terms: D000042:Absorption; D000328:Adult; D000368:Aged; D000596:Amino Acids / Q000097:blood; D000886:Anthropometry; D001823:Body Composition; D002364:Caseins / Q000008:administration & dosage / Q000493:pharmacokinetics*; D002853:Chromatography, Liquid; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007930:Leucine / Q000008:administration & dosage*; D008297:Male; D044342:Malnutrition / Q000150:complications / Q000188:drug therapy; D062407:Meals; D008875:Middle Aged; D008894:Milk Proteins / Q000008:administration & dosage / Q000493:pharmacokinetics*; D009124:Muscle Proteins / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D014176:Protein Biosynthesis; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000188:drug therapy*; D053719:Tandem Mass Spectrometry; D000067816:Whey Proteins
chemical_list: D000596:Amino Acids; D002364:Caseins; D007328:Insulin; D008894:Milk Proteins; D009124:Muscle Proteins; D000067816:Whey Proteins; D007930:Leucine
keywords: Chronic obstructive pulmonary disease; Hydrolyzed casein protein; Hydrolyzed whey protein; Leucine; Nutritionally depleted; Whole-body protein kinetics