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.
Moré
Jayaji M
JM
Department of Medicine, National Jewish Health, Denver, CO, USA.
Voelker
Dennis R
DR
Silveira
Lori J
LJ
Edwards
Michael G
MG
Chan
Edward D
ED
Bowler
Russell P
RP
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