title: Ischemic and endotoxin pre-conditioning reduce lung reperfusion injury-induced surfactant alterations.
abstract: BACKGROUND
  Pulmonary ischemia/reperfusion injury represents a common clinical phenomenon after lung transplantation, pulmonary embolism, and cardiac surgery with extracorporeal circulation. We investigated the influence of ischemic and endotoxin pre-conditioning on gas exchange and surfactant properties in a canine model of ischemia/reperfusion injury.
  
  
  METHODS
  Twenty-six foxhounds underwent 3 hours of warm ischemia of the left lung, followed by 8 hours of reperfusion. Ischemic pre-conditioning was performed for either 5 minutes (IPC-5) or by 2 10-minute ischemic periods (IPC-10), before ischemia. For endotoxin pre-conditioning, dogs were pre-treated by a daily intravenous application of increasing amounts of endotoxin for 6 days. No pre-conditioning was performed in the controls. Bronchoalveolar lavage was performed before ischemia/reperfusion injury (baseline) and after the 8-hour reperfusion period in the non-injured right and in the reperfused left lung. Bronchoalveolar lavage fluids were analyzed for the phospholipid-protein ratio, the content of large surfactant aggregates, the phospholipid and neutral lipid profile, the surfactant protein (SP) content, and for biophysical activity.
  
  
  RESULTS
  Severe surfactant alterations were observed in the ischemia/reperfusion-injured left lung, with increased protein concentrations and depressed concentrations of large surface aggregates, SP-B, dipalmitoylated phosphatidylcholine, and phosphatidylglycerol. Endotoxin pre-conditioning and IPC-5 were both capable of greatly preventing the ischemia/reperfusion injury-related deterioration of surfactant properties. IPC-10 exerted no effects. Endotoxin pre-conditioning and IPC-5, but not IPC-10, also prevented loss of gas exchange.
  
  
  CONCLUSIONS
  Ischemic and endotoxin pre-conditioning may protect against impairment of gas exchange in ischemia/reperfusion injury by restoring physiological surfactant properties.
authors.affiliation: Department of Internal Medicine, Med. Klinik II, Justus-Liebig University, Giessen, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Markart
authors.forename: Reinhold
authors.initials: R
authors.lastname: Schmidt
authors.forename: Clemens
authors.initials: C
authors.lastname: Ruppert
authors.forename: Christina
authors.initials: C
authors.lastname: Höres
authors.forename: Rolf E
authors.initials: RE
authors.lastname: Silber
authors.forename: Jochen
authors.initials: J
authors.lastname: Börgermann
authors.forename: Andreas
authors.initials: A
authors.lastname: Günther
authors.forename: Ivar
authors.initials: I
authors.lastname: Friedrich
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004195:Disease Models, Animal; D004285:Dogs; D004731:Endotoxins / Q000008:administration & dosage*; D004926:Escherichia coli; D006801:Humans; D019194:Ischemic Preconditioning; D008055:Lipids / Q000032:analysis; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008171:Lung Diseases / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D010713:Phosphatidylcholines / Q000032:analysis; D010743:Phospholipids / Q000032:analysis; D011659:Pulmonary Gas Exchange; D037661:Pulmonary Surfactant-Associated Proteins / Q000032:analysis*; D015427:Reperfusion Injury / Q000503:physiopathology / Q000517:prevention & control*
chemical_list: D004731:Endotoxins; D008055:Lipids; D008070:Lipopolysaccharides; D010713:Phosphatidylcholines; D010743:Phospholipids; D037661:Pulmonary Surfactant-Associated Proteins