Smoking reduces surfactant protein D and phospholipids in patients with and without chronic obstructive pulmonary disease.
BACKGROUND
Pulmonary surfactant D (SP-D) has important regulatory functions for innate immunity and has been implicated as a biomarker for chronic obstructive pulmonary disease (COPD). We hypothesized that COPD patients would have reduced bronchoalveolar lavage (BAL) fluid SP-D levels compared to healthy smoking and non-smoking controls.


METHODS
BAL SP-D and phospholipids were quantified and corrected for dilution in 110 subjects (65 healthy never smokers, 23 smokers with normal spirometry, and 22 smokers with COPD).


RESULTS
BAL SP-D was highest in never smokers (mean 51.9 μg/mL ± 7.1 μg/mL standard error) compared to both smokers with normal spirometry (16.0 μg/mL ± 11.8 μg/mL) and subjects with COPD (19.1 μg/mL ± 12.9 μg/mL; P < 0.0001). Among smokers with COPD, BAL SP-D correlated significantly with FEV1% predicted (R = 0.43; P < 0.05); however, the strongest predictor of BAL SP-D was smoking status. BAL SP-D levels were lowest in current smokers (12.8 μg/mL ± 11.0 μg/mL), intermediate in former smokers (25.2 μg/mL ± 14.2 μg/mL; P < 0.008), and highest in never smokers. BAL phospholipids were also lowest in current smokers (6.5 nmol ± 1.5 nmol), intermediate in former smokers (13.1 nmol ± 2.1 nmol), and highest in never smokers (14.8 nmol ± 1.1 nmol; P < 0.0001).


CONCLUSIONS
These data suggest that smokers, and especially current smokers, exhibit significantly reduced BAL SP-D and phospholipids compared to nonsmokers. Our findings may help better explain the mechanism that leads to the rapid progression of disease and increased incidence of infection in smokers.
Department of Medicine, National Jewish Health, Denver, CO, USA.
Jayaji M
JM
Moré
Dennis R
DR
Voelker
Lori J
LJ
Silveira
Michael G
MG
Edwards
Edward D
ED
Chan
Russell P
RP
Bowler
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D005260:Female; D006801:Humans; D008168:Lung / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010743:Phospholipids / Q000378:metabolism*; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000503:physiopathology; D037663:Pulmonary Surfactant-Associated Protein D / Q000032:analysis / Q000378:metabolism*; D012044:Regression Analysis; D012906:Smoke / Q000009:adverse effects; D012907:Smoking / Q000009:adverse effects / Q000378:metabolism*; D013147:Spirometry; D055815:Young Adult
D015415:Biomarkers; D010743:Phospholipids; D037663:Pulmonary Surfactant-Associated Protein D; D012906:Smoke