title: Combat-training stress in soldiers increases S100B, a marker of increased blood-brain-barrier permeability, and induces immune activation.
abstract: BACKGROUND
  Experimental data suggest stress-related cognitive dysfunction may be associated with increased blood-brain-barrier (BBB) permeability secondary to immune activation.
  
  
  METHODS
  We investigated the relationship between prolonged and intense physical and psychological combat-training stress, immune activation and blood-brain-barrier permeability in 37 healthy male army medical rapid response troops.
  
  
  RESULTS
  Soldiers during intense combat training showed greater self-reported stress, anxiety and depression levels than at rest, as assessed by specific questionnaires. S100B, a marker of BBB permeability, as well as serum cortisol, IL-6 and TNF-α concentrations, were significantly increased in soldiers during combat training compared to rest (all p<0.05). Serum S100B correlated negatively with morning serum cortisol in soldiers during combat training, but not during the rest period (r=-0.387, p<0.05).
  
  
  CONCLUSIONS
  We conclude that combat training inducing significant levels of stress, depression and anxiety is accompanied by evidence of increased blood-brain barrier permeability and by increases in systemic pro-inflammatory mediators.
authors.affiliation: Neurogastroenterology Research Unit, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Li
authors.affiliation: Neurogastroenterology Research Unit, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Clive H
authors.initials: CH
authors.lastname: Wilder-Smith
authors.affiliation: Combat Care Laboratory, DSO National Laboratories, Singapore.
authors.forename: Mary Enci
authors.initials: ME
authors.lastname: Kan
authors.affiliation: Combat Care Laboratory, DSO National Laboratories, Singapore.
authors.forename: Jia
authors.initials: J
authors.lastname: Lu
authors.affiliation: Neurogastroenterology Research Unit, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Yang
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Neurogastroenterology Research Unit, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Reuben K
authors.initials: RK
authors.lastname: Wong
mesh_terms: D000328:Adult; D001007:Anxiety / Q000209:etiology; D015415:Biomarkers / Q000097:blood; D001812:Blood-Brain Barrier / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000502:physiology; D003863:Depression / Q000209:etiology; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007249:Inflammation / Q000209:etiology; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008889:Military Personnel; D012146:Rest / Q000502:physiology; D064568:S100 Calcium Binding Protein beta Subunit / Q000097:blood*; D013312:Stress, Physiological / Q000276:immunology / Q000502:physiology; D013315:Stress, Psychological / Q000097:blood* / Q000209:etiology / Q000276:immunology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D055815:Young Adult
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D064568:S100 Calcium Binding Protein beta Subunit; C579160:S100B protein, human; D014409:Tumor Necrosis Factor-alpha; D006854:Hydrocortisone