title: Composition of human pulmonary surfactant varies with exercise and level of fitness.
abstract: We have tested the hypothesis that the composition of alveolar surfactant varies with pattern of breathing and level of fitness. We examined three major components of surfactant, surfactant protein A (SP-A), disaturated phospholipids (DSP), and cholesterol (CHOL) in bronchoalveolar lavage (BAL) fluid from 12 healthy men before and after exercise. Fitness was assessed as work load/heart rate ([kpm.min-1]/[HR.HRmax-1]) achieved during cycling for 30 min at 90% theoretical maximal heart rate. Using a bronchoscope, four 20-ml vols of 0.15 M NaCl at 37 degrees C were instilled and then recovered from first a right upper and then a right lower lobe segmental bronchus. As we found no differences in the BAL from upper and lower lobes, the fluid was combined. We found a direct relationship between CHOL and DSP (rs = 0.84, p < 0.001), SP-A and CHOL (rs = 0.40, p < 0.025), and between SP-A and DSP (rs = 0.44, p < 0.025). The change in the ratios CHOL/DSP, SP-A/CHOL, and SP-A/DSP immediately after exercise was correlated with fitness (rs = -0.56, p < 0.025; rs = 0.75, p < 0.005; rs = 0.62, p < 0.025, respectively). We conclude that the composition of surfactant can change rapidly with exercise in a manner related to fitness, and we suggest that this is consistent with the existence of at least two pools of tissue surfactant of different composition supplying the alveolar compartment.
authors.affiliation: Department of Human Physiology, School of Medicine, Flinders Medical Centre, Adelaide, Australia.
authors.forename: I R
authors.initials: IR
authors.lastname: Doyle
authors.forename: M E
authors.initials: ME
authors.lastname: Jones
authors.forename: H A
authors.initials: HA
authors.lastname: Barr
authors.forename: S
authors.initials: S
authors.lastname: Orgeig
authors.forename: A J
authors.initials: AJ
authors.lastname: Crockett
authors.forename: C F
authors.initials: CF
authors.lastname: McDonald
authors.forename: T E
authors.initials: TE
authors.lastname: Nicholas
mesh_terms: D000328:Adult; D000918:Antibody Specificity; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry* / Q000166:cytology; D002452:Cell Count; D002784:Cholesterol / Q000032:analysis* / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D015444:Exercise; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010713:Phosphatidylcholines / Q000032:analysis* / Q000276:immunology; D010809:Physical Fitness; D011510:Proteolipids / Q000032:analysis* / Q000276:immunology; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000032:analysis* / Q000276:immunology
chemical_list: D010713:Phosphatidylcholines; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; C017463:lecithins, disaturated; D002784:Cholesterol