title: Changes in stress hormones and metabolism during a 105-day simulated Mars mission.
abstract: BACKGROUND
  The Mars-105 project was aimed at simulating crew's activities, workload, and communication during a mission to Mars, evaluating the homeostatic adaptations to prolonged confinement and cohabitation.
  
  
  METHODS
  Fasting plasma glucose (FPG) and insulin, C-peptide, leptin, cortisol, and NGF and BDNF plasma levels were monitored in six healthy nonsmoking male subjects taking part in a 105-d Mars mission simulation. Samples were collected from each subject before (0 wk), during (2.5 wk; 5 wk; 10 wk; 15 wk), and after confinement (+1 wk).
  
  
  RESULTS
  Confinement resulted in impaired glucometabolic parameters, since FPG increased during the first 5 wk (baseline: 85.2 ± 10.8 mg · dl⁻¹; 2.5 wk: 98.4 ± 4.7 mg · dl⁻¹; 5 wk: 92.5 ± 6.0 mg · dl⁻¹) and insulin dropped at 2.5 wk (baseline: 14.4 ± 4.8 mU · L⁻¹; 2.5 wk: 7.7 ± 2.1 mU · L⁻¹), subsequently returning to baseline values. HOMA-IR paralleled plasma insulin, dropping to 1.8 ± 0.5 at 2.5 wk (baseline: 3.0 ± 1.2). At all time-points tested, plasma leptin levels were decreased (baseline: 4.4 ± 3.3 ng · dl⁻¹; 2.5 wk: 1.6 ± 1.2 ng · dl⁻¹; 5 wk: 1.3 ± 0.8 ng · dl⁻¹; 10 wk: 1.5 ± 1.1 ng · dl⁻¹; 15 wk:1.7 ± 0.8 ng · dl⁻¹), whereas cortisol levels were increased (baseline: 10.8 ± 4.9 ng · dl⁻¹; 2.5 wk: 16.8 ± 3.5 ng · dl⁻¹; 5 wk: 18.1 ± 7.6 ng · dl⁻¹; 10 wk: 18.1 ± 8.3 ng · dl⁻¹; 15 wk:14.2 ± 4.4 ng · dl⁻¹), resulting in a negative correlation between these hormones. BDNF levels increased only at 5 and 10 wk (baseline: 67.1 ± 36.0 pg · ml⁻¹; 5 wk: 164 ± 54 pg · ml⁻¹; and 10 wk: 110.2 ± 28.9 pg · ml⁻¹).
  
  
  CONCLUSIONS
  The data obtained with the Mars-105 experiment suggest that environmental stress has a strong impact upon metabolic and stress response, indicating the need for further studies and the implementation of specific countermeasures.
authors.affiliation: Institute for Biomedical Problems, Moscow, Russia.
authors.forename: Felice
authors.initials: F
authors.lastname: Strollo
authors.forename: Galina
authors.initials: G
authors.lastname: Vassilieva
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Ruscica
authors.forename: Mariangela
authors.initials: M
authors.lastname: Masini
authors.forename: Daniela
authors.initials: D
authors.lastname: Santucci
authors.forename: Luisa
authors.initials: L
authors.lastname: Borgia
authors.forename: Paolo
authors.initials: P
authors.lastname: Magni
authors.forename: Fabio
authors.initials: F
authors.lastname: Celotti
authors.forename: Igor
authors.initials: I
authors.lastname: Nikiporuc
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000223:Adaptation, Psychological / Q000502:physiology*; D000328:Adult; D000337:Aerospace Medicine; D015415:Biomarkers / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood; D002096:C-Peptide / Q000097:blood; D020378:Confined Spaces; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood; D008297:Male; D018535:Mars; D008991:Monitoring, Physiologic; D020932:Nerve Growth Factor / Q000097:blood; D009752:Nutritional Status; D013026:Space Flight
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D019208:Brain-Derived Neurotrophic Factor; D002096:C-Peptide; D007328:Insulin; D020738:Leptin; D020932:Nerve Growth Factor; D006854:Hydrocortisone