title: Whey protein plus bicarbonate supplement has little effects on structural atrophy and proteolysis marker immunopatterns in skeletal muscle disuse during 21 days of bed rest.
abstract: OBJECTIVE
  To investigate the effect of whey protein plus potassium bicarbonate supplement on disused skeletal muscle structure and proteolysis after bed rest (BR).
  
  
  METHODS
  Soleus (SOL) and vastus lateralis (VL) biopsies were sampled from ten (n=10) healthy male subjects (aged 31±6 years) who did BR once with and once without protein supplement as a dietary countermeasure (cross-over study design). The structural changes (myofibre size and type distribution) were analysed by histological sections, and muscle protein breakdown indirectly via the proteolysis markers, calpain 1 and 3, calpastatin, MuRF1 and 2, both in muscle homogenates and by immunohistochemistry.
  
  
  RESULTS
  BR caused size-changes in myofiber cross-sectional area (FCSA, SOL, p=0,004; VL, p=0.03), and myofiber slow-to-fast type transition with increased hybrids (SOL, p=0.043; VL, p=0.037) however with campaign differences in SOL (p<0.033). No significant effect of BR and supplement was found by any of the key proteolysis markers.
  
  
  CONCLUSIONS
  Campaign differences in structural muscle adaptation may be an issue in cross-over design BR studies. The whey protein plus potassium bicarbonate supplement did not attenuate atrophy and fibre type transition during medium term bed rest. Alkaline whey protein supplements may however be beneficial as adjuncts to exercise countermeasures in disuse.
authors.affiliation: Charité Universitätsmedizin Berlin, Vegetative Anatomy.
authors.forename: D
authors.initials: D
authors.lastname: Blottner
authors.forename: A
authors.initials: A
authors.lastname: Bosutti
authors.forename: H
authors.initials: H
authors.lastname: Degens
authors.forename: G
authors.initials: G
authors.lastname: Schiffl
authors.forename: M
authors.initials: M
authors.lastname: Gutsmann
authors.forename: J
authors.initials: J
authors.lastname: Buehlmeier
authors.forename: J
authors.initials: J
authors.lastname: Rittweger
authors.forename: B
authors.initials: B
authors.lastname: Ganse
authors.forename: M
authors.initials: M
authors.lastname: Heer
authors.forename: M
authors.initials: M
authors.lastname: Salanova
mesh_terms: D000328:Adult; D001510:Bed Rest / Q000009:adverse effects*; D001639:Bicarbonates / Q000627:therapeutic use*; D018592:Cross-Over Studies; D019587:Dietary Supplements; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008894:Milk Proteins / Q000627:therapeutic use*; D009133:Muscular Atrophy / Q000517:prevention & control*; D017680:Potassium Compounds / Q000627:therapeutic use*; D059748:Proteolysis / Q000187:drug effects*; D000067816:Whey Proteins; D055815:Young Adult
chemical_list: D001639:Bicarbonates; D008894:Milk Proteins; D017680:Potassium Compounds; D000067816:Whey Proteins; C026329:potassium bicarbonate