title: Therapeutic hypothermia cardioprotection in murine hemorrhagic shock/resuscitation differentially affects p38α/p38γ, Akt, and HspB1.
abstract: BACKGROUND
  Therapeutic hypothermia (TH) has demonstrated great potential for forestalling cardiovascular collapse and improving outcomes in the setting of severe hemorrhagic shock (HS). We used an established mouse model of severe HS to study the response of interrelated cardiac-signaling proteins p38, HspB1, and Akt to shock, resuscitation, and cardioprotective TH.
  
  
  METHODS
  Adult female C57BL6/J mice were bled and maintained at a mean arterial pressure of 35 mm Hg. After 30 minutes, mice were randomized to 120 minutes of TH (33°C ± 0.5°C) or continued normothermia at 37°C. After 90 minutes, animals were resuscitated and monitored for 180 minutes. Cardiac p38, Akt, and HspB1 phosphorylation (p-p38, p-Akt, and p-HspB1), expression, and Akt/HspB1 interactions were measured at serial time points during HS and resuscitation. Markers of mitochondrial damage (plasma cytochrome c), inflammation (myeloperoxidase), and apoptosis (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling) were analyzed.
  
  
  RESULTS
  By 15 minutes HS, p-p38 and p-HspB1 significantly increased while p-Akt(T308) decreased (p < 0.05). TH attenuated phosphorylation of the p38α isoform during HS and increased phosphorylation of the p38γ isoform during both HS and early resuscitation (p < 0.05). TH increased Akt/HspB1 coimmunoprecipitation during early resuscitation and increased p-Akt and HspB1 expression during late resuscitation (p < 0.05). Finally, TH attenuated the myocardial myeloperoxidase and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining and plasma cytochrome c during late resuscitation.
  
  
  CONCLUSIONS
  TH increases phosphorylation of p38γ during both HS and early resuscitation, but attenuates phosphorylation of p38α, increases Akt/HspB1 interaction, and modulates Akt phosphorylation during HS and resuscitation. Such TH-related signaling events are associated with reduced cardiac inflammation, apoptosis, and mitochondrial injury.
authors.affiliation: Department of Emergency Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: David G
authors.initials: DG
authors.lastname: Beiser
authors.forename: Huashan
authors.initials: H
authors.lastname: Wang
authors.forename: Anshuman
authors.initials: A
authors.lastname: Das
authors.forename: Evgeny
authors.initials: E
authors.lastname: Berdyshev
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Alan R
authors.initials: AR
authors.lastname: Leff
authors.forename: Susan A
authors.initials: SA
authors.lastname: Stern
authors.forename: Terry L
authors.initials: TL
authors.lastname: Vanden Hoek
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis; D045304:Cytochromes c / Q000097:blood; D004195:Disease Models, Animal; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006360:Heat-Shock Proteins / Q000378:metabolism; D007036:Hypothermia, Induced; D015151:Immunoblotting; D047468:Immunoprecipitation; D020287:In Situ Nick-End Labeling; D051379:Mice; D008810:Mice, Inbred C57BL; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011897:Random Allocation; D012151:Resuscitation / Q000379:methods; D012771:Shock, Hemorrhagic / Q000150:complications* / Q000628:therapy*; D018709:Statistics, Nonparametric; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D045304:Cytochromes c; D051057:Proto-Oncogene Proteins c-akt; D048051:p38 Mitogen-Activated Protein Kinases