Composition of alveolar surfactant changes with training in humans.
OBJECTIVE
We test the hypothesis that the changes we observed previously in the relative amounts of disaturated phospholipids (DSP), cholesterol (CHOL), and surfactant protein-A (SP-A) in human alveolar surfactant in response to acute exercise, and which were related to fitness, can be induced by training.


METHODS
We examine the effect of 7 weeks' training on these major surfactant components, together with surfactant protein-B (SP-B), in bronchoalveolar lavage fluid harvested from 17 males, both at rest and after acute exercise. Fitness was assessed as workload/heart rate achieved during cycling for 30 min at 90% of theoretical maximal heart rate, and was increased in all subjects following training (mean increase 22.2+/-3.91%; P = 0.001).


RESULTS
Training significantly increased the SP-A/DSP, SP-B/DSP, SP-A/CHOL and SP-A/SP-B ratios in whole surfactant harvested from subjects both at rest and immediately following exercise. Training also increased the SP-B/CHOL ratio at rest. Changes were particularly marked at rest in the SP-A/DSP, SP-A/CHOL, and SP-B/CHOL ratios in the tubular myelin-rich fraction, and after exercise in the SP-A/DSP, SP-A/CHOL, and SP-A/SP-B ratios in the tubular myelin-poor fraction.


CONCLUSIONS
We conclude that training markedly alters the composition of alveolar surfactant both at rest and with exercise; the physiological significance of these changes remains to be determined.
Doyle
I R
IR
Department of Human Physiology, School of Medicine, Flinders University, Adelaide, South Australia, Australia.
Morton
S
S
Crockett
A J
AJ
Barr
H A
HA
Davidson
K G
KG
Jones
M J
MJ
Jones
M E
ME
Nicholas
T E
TE
D000293:Adolescent; D000328:Adult; D018893:Bronchoalveolar Lavage; D002784:Cholesterol / Q000032:analysis / Q000097:blood; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D010743:Phospholipids / Q000032:analysis; D010806:Physical Education and Training; D010809:Physical Fitness / Q000502:physiology*; D011510:Proteolipids / Q000032:analysis; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000032:analysis / Q000737:chemistry*; D015203:Reproducibility of Results; D012119:Respiration; D012146:Rest / Q000502:physiology
D008055:Lipids; D010743:Phospholipids; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D002784:Cholesterol