title: Kidney function and urine protein composition in healthy volunteers during space station fitness tests.
abstract: BACKGROUND
  There is a close physiological connection between muscular activity and kidney function. During physical exercise (PE) the qualitative and quantitative composition of urine changes. This paper explores the influence of moderate PE on urine protein composition. The study of urine protein composition will help to make corrections to the existing methods of countermeasures.
  
  
  METHODS
  There were 10 healthy men who exercised on a treadmill similar to the one onboard the International Space Station. We analyzed their urinary proteome composition, potassium level, sodium level, and their level of osmotically active substances before and after PE.
  
  
  RESULTS
  After moderate PE, a small increase in urine flow speed and a constant glomerular filtration rate were noted. The average-group index of total protein excretion within the urine was reliably increased. From the 148 proteins identified in the urine, 64 were associated with known tissue origin. We found that protein penetration into the urine had a positive correlation with their tissue expression. Selectivity of the glomerular barrier during PE decreased and high-molecular weight proteins penetrated through the glomerular barrier more easily after PE.
  
  
  CONCLUSIONS
  Performance of moderate intensity physical exercise of short duration did not lead to an increase in the glomerular filtration rate nor did diuresis increase above the limits of baseline variability. However, the protein excretion rate increased after PE. We also observed that protein composition drift indicated a change in the set of biological processes in which a given protein participated, in some cases activating, in some cases inactivating them.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Fomina
authors.forename: Natalia Iu
authors.initials: NIu
authors.lastname: Lisova
authors.forename: Kirill S
authors.initials: KS
authors.lastname: Kireev
authors.forename: Evgeny S
authors.initials: ES
authors.lastname: Tiys
authors.forename: Alexey S
authors.initials: AS
authors.lastname: Kononikhin
authors.forename: Irina M
authors.initials: IM
authors.lastname: Larina
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D015444:Exercise / Q000502:physiology*; D005919:Glomerular Filtration Rate; D064368:Healthy Volunteers; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000502:physiology*; D007677:Kidney Function Tests; D008297:Male; D011188:Potassium / Q000652:urine; D011507:Proteinuria / Q000652:urine*; D020543:Proteome / Q000032:analysis*; D012964:Sodium / Q000652:urine; D013026:Space Flight; D055815:Young Adult
chemical_list: D020543:Proteome; D012964:Sodium; D011188:Potassium