title: Cerebral microcirculation during mild head injury after a contusion and acceleration experimental model in sheep.
abstract: BACKGROUND
  Cerebral microcirculation after head injury is heterogeneous and temporally variable. Regions at risk of infarction such as peri-contusional areas are vulnerable to anaemia. However, direct quantification of the cerebral microcirculation is clinically not feasible. This study describes a novel experimental head injury model correlating cerebral microcirculation with histopathology analysis.
  
  
  OBJECTIVE
  To test the hypothesis that cerebral microcirculation at the ischaemic penumbrae is reduced over time when compared with non-injured regions.
  
  
  METHODS
  Merino sheep were instrumented using a transeptal catheter to inject coded microspheres into the left cardiac atrium, ensuring systemic distribution. After a blunt impact over the left parietal region, cytometric analyses quantified cerebral microcirculation and amyloid precursor protein staining identified axonal injury in pre-defined anatomical regions. A mixed effect regression model assessed the hourly blood flow results during 4 hours after injury.
  
  
  RESULTS
  Cerebral microcirculation showed temporal reductions with minimal amyloid staining except for the ipsilateral thalamus and medulla.
  
  
  CONCLUSIONS
  The spatial heterogeneity and temporal reduction of cerebral microcirculation in ovine models occur early, even after mild head injury, independent of the intracranial pressure and the level of haemoglobin. Alternate approaches to ensure recovery of regions with reversible injury require a targeted assessment of cerebral microcirculation.
authors: a Critical Care Research Group, University of Queensland , Herston , QLD , Australia.|b Intensive Care Department.
authors: Judith
authors: J
authors: Bellapart
authors: c Department of Anaesthesia.
authors: Catherine
authors: C
authors: Abi-Fares
authors: d Histopathology Department , Royal Brisbane and Women's Hospital , Herston , QLD , Australia.
authors: Kylie
authors: K
authors: Cuthbertson
authors: a Critical Care Research Group, University of Queensland , Herston , QLD , Australia.|e Medical Engineering Research Facility, Queensland University of Technology , Stafford Heights , QLD , Australia.
authors: Kimble
authors: K
authors: Dunster
authors: a Critical Care Research Group, University of Queensland , Herston , QLD , Australia.|e Medical Engineering Research Facility, Queensland University of Technology , Stafford Heights , QLD , Australia.
authors: Sara
authors: S
authors: Diab
authors: a Critical Care Research Group, University of Queensland , Herston , QLD , Australia.|f Department of Cardiology , The Prince Charles Hospital , Chermside , QLD , Australia.
authors: David G
authors: DG
authors: Platts
authors: a Critical Care Research Group, University of Queensland , Herston , QLD , Australia.|f Department of Cardiology , The Prince Charles Hospital , Chermside , QLD , Australia.
authors: Christopher
authors: C
authors: Raffel
authors: g Medical School Research Centre , Adelaide , SA , Australia.
authors: Levon
authors: L
authors: Gabrielian
authors: a Critical Care Research Group, University of Queensland , Herston , QLD , Australia.|h Institute of Health and Biomedical Innovation & School of Public Health and Social Work, Queensland University of Technology , Kelvin Grove , QLD , Australia.
authors: Adrian
authors: A
authors: Barnett
authors: i School of Medicine, University of Queensland , Herston , QLD , Australia.|j Griffith University , Southport , Australia.
authors: Jennifer
authors: J
authors: Paratz
authors: b Intensive Care Department.
authors: Rob
authors: R
authors: Boots
authors: a Critical Care Research Group, University of Queensland , Herston , QLD , Australia.|k Intensive Care Department , The Prince Charles Hospital , Chermside , QLD , Australia.
authors: John F
authors: JF
authors: Fraser
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D000818:Animals; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006259:Craniocerebral Trauma / Q000473:pathology* / Q000503:physiopathology*; D004195:Disease Models, Animal; D004452:Echocardiography; D066128:Gray Matter / Q000378:metabolism / Q000473:pathology*; D006454:Hemoglobins / Q000378:metabolism; D007427:Intracranial Pressure / Q000502:physiology; D008863:Microspheres; D012756:Sheep; D015599:Trauma Severity Indices
chemical_list: D016564:Amyloid beta-Protein Precursor; D006454:Hemoglobins
keywords: Brain trauma; axonal damage; cerebral blood flow