title: Lung surfactant protein D (SP-D) response and regulation during acute and chronic lung injury.
abstract: BACKGROUND
  Surfactant protein D (SP-D) is a collection that plays important roles in modulating host defense functions and maintaining phospholipid homeostasis in the lung. The aim of current study was to characterize comparatively the SP-D response in bronchoalveolar lavage (BAL) and serum in three murine models of lung injury, using a validated ELISA technology for estimation of SP-D levels.
  
  
  METHODS
  Mice were exposed to lipopolysaccharide, bleomycin, or Pneumocystis carinii (Pc) and sacrificed at different time points.
  
  
  RESULTS
  In lipopolysaccharide-challenged mice, the level of SP-D in BAL increased within 6 h, peaked at 51 h (4,518 ng/ml), and returned to base level at 99 h (612 ng/ml). Serum levels of SP-D increased immediately (8.6 ng/ml), peaked at 51 h (16 ng/ml), and returned to base levels at 99 h (3.8 ng/ml). In a subacute bleomycin inflammation model, SP-D levels were 4,625 and 367 ng/ml in BAL and serum, respectively, 8 days after exposure. In a chronic Pc inflammation model, the highest level of SP-D was observed 6 weeks after inoculation, with BAL and serum levels of 1,868 and 335 ng/ml, respectively.
  
  
  CONCLUSIONS
  We conclude that serum levels of SP-D increase during lung injury, with a sustained increment during chronic inflammation compared with acute inflammation. A quick upregulation of SP-D in serum in response to acute airway inflammation supports the notion that SP-D translocates from the airways into the vascular system, in favor of being synthesized systemically. The study also confirms the concept of using increased SP-D serum levels as a biomarker of especially chronic airway inflammation.
authors: Department of Otorhinolaryngology, Odense University Hospital, Sdr. Boulevard 29, 5000, Odense C, Denmark. maria.quisgaard@ouh.regionsyddanmark.dk
authors: Maria Quisgaard
authors: MQ
authors: Gaunsbaek
authors: Karina Juhl
authors: KJ
authors: Rasmussen
authors: Michael F
authors: MF
authors: Beers
authors: Elena N
authors: EN
authors: Atochina-Vasserman
authors: Soren
authors: S
authors: Hansen
mesh_terms: D055371:Acute Lung Injury / Q000097:blood / Q000139:chemically induced / Q000378:metabolism* / Q000382:microbiology; D000818:Animals; D001761:Bleomycin; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007150:Immunohistochemistry; D008070:Lipopolysaccharides; D008168:Lung / Q000378:metabolism* / Q000382:microbiology; D055370:Lung Injury / Q000097:blood / Q000139:chemically induced / Q000378:metabolism* / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D045363:Pneumocystis carinii; D011020:Pneumonia, Pneumocystis / Q000097:blood / Q000378:metabolism* / Q000382:microbiology; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood / Q000378:metabolism*; D013997:Time Factors
chemical_list: D008070:Lipopolysaccharides; D037663:Pulmonary Surfactant-Associated Protein D; D001761:Bleomycin