title: Serum concentration of surfactant protein D in horses with lower airway inflammation.
abstract: BACKGROUND
  Surfactant protein D (SP-D), mainly synthesised by alveolar type II cells and nonciliated bronchiolar cells, is one important component of innate pulmonary immunity. In man, circulating concentrations of SP-D are routinely used as biomarkers for pulmonary injury. To date, serum SP-D levels have only been investigated in horses in an experimental model of bacterial airway infection.
  
  
  OBJECTIVE
  To compare serum SP-D concentrations at rest and after exercise in horses with and without inflammatory airway disease (IAD).
  
  
  METHODS
  Venous blood samples were collected from 42 Standardbred racehorses at rest and 60 min after performing a standardised treadmill exercise test. Tracheal wash and bronchoalveolar lavage fluid (BALF) samples were collected after exercise. Based on BALF cytology, 22 horses were defined as IAD-affected and 20 classified as controls. Serum SP-D concentrations were assessed using a commercially available ELISA kit and statistically compared between groups of horses and sampling times.
  
  
  RESULTS
  Serum concentrations of SP-D in IAD-affected horses were significantly higher than those of control horses, both at rest and after exercise. Within the IAD-affected group, no significant correlation was found between serum SP-D concentrations and BALF cytology. Within each group of horses (IAD and control), no significant influence of exercise was found on serum SP-D levels.
  
  
  CONCLUSIONS
  This is the first study determining serum SP-D concentrations in a noninfectious, naturally occurring form of lower airway inflammation in horses. The results highlight that IAD is associated with a detectable, though moderate, increase of circulating SP-D levels.
  
  
  CONCLUSIONS
  Serum concentration of surfactant protein D could represent a potentially valuable and readily accessible blood biomarker of equine lower airway inflammation.
authors.affiliation: Frank Duncombe Laboratory, Route de Rosel, Caen Cedex, France. eric.richard@calvados.fr
authors.forename: E A
authors.initials: EA
authors.lastname: Richard
authors.forename: P-H
authors.initials: PH
authors.lastname: Pitel
authors.forename: U
authors.initials: U
authors.lastname: Christmann
authors.forename: P
authors.initials: P
authors.lastname: Lekeux
authors.forename: G
authors.initials: G
authors.lastname: Fortier
authors.forename: S
authors.initials: S
authors.lastname: Pronost
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D016022:Case-Control Studies; D005080:Exercise Test / Q000662:veterinary; D005260:Female; D006734:Horse Diseases / Q000097:blood* / Q000378:metabolism; D006736:Horses; D007249:Inflammation / Q000097:blood / Q000378:metabolism / Q000662:veterinary*; D008297:Male; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood* / Q000378:metabolism; D012140:Respiratory Tract Diseases / Q000097:blood / Q000378:metabolism / Q000662:veterinary*
chemical_list: D037663:Pulmonary Surfactant-Associated Protein D