title: Time course of hemosiderin production by alveolar macrophages in a murine model.
abstract: OBJECTIVE
  The diagnosis of alveolar hemorrhage is assisted by the presence of hemosiderin-laden macrophages (HLMs) in the BAL fluid or lung tissue. Despite the importance of this diagnostic method in clinical settings, limited information is available on the formation and clearance of HLMs as a function of time. The objectives of this study are to determine the time course of HLMs within the BAL and lung tissue, and to evaluate the effect of a single blood aspiration on the recruitment of inflammatory cells within the BAL.
  
  
  METHODS
  Under light anesthesia, Balb/c mice received a single intranasal instillation of species-specific blood (50 microL). Control animals received heparinized sterile saline solution in a similar manner. At several time points after blood aspiration, BAL was recovered for cell differentials and determination of HLMs. The time course for HLMs was also established in the lung tissue.
  
  
  RESULTS
  Hemosiderin staining within alveolar macrophages was first detected in the BAL and lung tissue at day 3, peaked at day 7, and persisted through 2 months. The analysis of the BAL revealed an increased number of total cells, with an acute inflammatory reaction that resolved within 2 weeks.
  
  
  CONCLUSIONS
  Our findings demonstrate the validity of this model for the study of HLM production after blood aspiration. Additional work using animal models of lung hemorrhage is needed to further characterize the cellular events leading to clearance of erythrocytes within the lung.
authors.affiliation: Department of Pediatrics, Division of Pulmonary Medicine, Baylor College of Medicine, Houston, TX 77030-2399, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Epstein
authors.forename: O
authors.initials: O
authors.lastname: Elidemir
authors.forename: G N
authors.initials: GN
authors.lastname: Colasurdo
authors.forename: L L
authors.initials: LL
authors.lastname: Fan
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D005260:Female; D006470:Hemorrhage / Q000175:diagnosis / Q000473:pathology; D006485:Hemosiderin / Q000378:metabolism*; D008171:Lung Diseases / Q000175:diagnosis / Q000473:pathology; D016676:Macrophages, Alveolar / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D012680:Sensitivity and Specificity
chemical_list: D006485:Hemosiderin