title: Warming to 39°C but Not to 37°C Ameliorates the Effects on the Monocyte Response by Hypothermia.
abstract: OBJECTIVE
  To investigate whether warming to normal body temperature or to febrile range temperature (39°C) is able to reverse the detrimental effects of hypothermia.
  
  
  BACKGROUND
  Unintentional intraoperative hypothermia is a well-described risk factor for surgical site infections but also sepsis. We have previously shown that hypothermia prolongs the proinflammatory response whereas normothermia and especially febrile range temperature enhance the anti-inflammatory response.
  
  
  METHODS
  Primary human monocytes were isolated from healthy volunteers. After stimulation with LPS (Lipopolysaccharide), the monocytes were exposed to 32°C for 3  hours or 6  hours and then warmed at either 37°C or 39°C for the remaining 33  hours or 36  hours, respectively. Tumor necrosis factor α, interleukin 10, and the expression of miR-155 and miR-101 were assessed at 24  hours and 36  hours.
  
  
  RESULTS
  Warming to 37°C does not normalize monocyte cytokine secretion within 36  hours, whereas warming to 39°C partially reverses the effects of hypothermia on monocyte function. Both miR-155 and miR-101 were suppressed after the warming episode. However, 39°C had a stronger suppressive effect than 37°C. The duration of hypothermia and the warming temperature seem to be critical for a full reversibility of the effects of hypothermia.
  
  
  CONCLUSIONS
  Warming to normal body temperature (37°C) does not restore normal monocyte function in vitro. These data suggest that hypothermic patients should be warmed to febrile range temperatures. Furthermore, febrile range temperatures should be investigated as a means to modulate the inflammatory response in patients with systemic infections.
authors.affiliation: Price Institute of Surgical Research, Hiram C. Polk, Jr., M.D. Department of Surgery, University of Louisville School of Medicine, Louisville, KY.
authors.forename: Adrian T
authors.initials: AT
authors.lastname: Billeter
authors.forename: Jonathan
authors.initials: J
authors.lastname: Rice
authors.forename: Devin
authors.initials: D
authors.lastname: Druen
authors.forename: Seth
authors.initials: S
authors.lastname: Sklare
authors.forename: Samuel
authors.initials: S
authors.lastname: Walker
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Gardner
authors.forename: Hiram C
authors.initials: HC
authors.lastname: Polk
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006801:Humans; D007035:Hypothermia / Q000378:metabolism* / Q000628:therapy*; D016753:Interleukin-10 / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D035683:MicroRNAs / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism*; D017694:Rewarming / Q000379:methods*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D015415:Biomarkers; D016207:Cytokines; D015850:Interleukin-6; D035683:MicroRNAs; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D018664:Interleukin-12