COPD and Inhaled Steroids Affect SP-D Levels
Author Information
Author(s): Michael W Sims, Ruth M Tal-Singer, Sonja Kierstein, Ali I Musani, Michael F Beers, Reynold A Panettieri, Angela Haczku
Primary Institution: University of Pennsylvania
Hypothesis
Chronic cigarette smoking and COPD are independently associated with lower SP-D levels in the lung.
Conclusion
COPD is associated with lower levels of SP-D, while inhaled corticosteroid use is linked to higher levels of SP-D in the lung.
Supporting Evidence
- COPD subjects had significantly lower SP-D levels than healthy controls (median 449 ng/mL vs. 714 ng/mL, p = 0.03).
- Among former smokers, those with COPD had lower SP-D levels compared to healthy former smokers (median 502 ng/mL vs. 1067 ng/mL, p = 0.01).
- Inhaled corticosteroid use was associated with higher SP-D levels in COPD subjects (median 765 ng/mL vs. 463 ng/mL, p = 0.15).
Takeaway
People with COPD have less of a protective protein called SP-D in their lungs, but using inhaled steroids can help increase its levels.
Methodology
Bronchoalveolar lavage fluid was collected from subjects with COPD and healthy controls, and SP-D levels were measured using ELISA.
Potential Biases
Potential confounding factors such as age, sex, race, and smoking status were controlled for, but residual confounding may still exist.
Limitations
The study was cross-sectional and could not determine causality; it was also underpowered to detect differences in SP-D levels among severe COPD stages.
Participant Demographics
20 subjects with COPD (8 former smokers, 12 current smokers) and 15 healthy controls (5 never smokers, 3 remote former smokers, 7 current smokers).
Statistical Information
P-Value
0.01
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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