Related Experiment Video
Updated: Dec 1, 2025
Measuring Carbon Content in Airway Macrophages Exposed to Carbon-Containing Particulate Matters
Published on: July 12, 2024
Black Carbon Content in Airway Macrophages is Associated with Reduced CD80 Expression and Increased Exacerbations in
Vickram Tejwani1, Eric Moughames2, Karthik Suresh1
1Johns Hopkins University, Division of Pulmonary and Critical Care Medicine, Baltimore, Maryland, United States.
Background:
Chronic obstructive pulmonary disease (COPD) is characterized by recurrent exacerbations. Macrophages play a critical role in immune response and tissue repair in COPD. Airway macrophages (AM) are exposed to environmental exposures which are retained in the cytoplasmic material. Both biomass and particulate matter have been linked to higher AM black carbon. It is unknown if AM black carbon is associated with COPD morbidity and macrophage phenotype.
Methods:
Former smokers with COPD were enrolled and sputum induction was performed to obtain airway macrophages. Macrophages underwent black carbon quantification and flow cytometry phenotyping. Health information was obtained the same day as sputum induction and prospective exacerbations were assessed by monthly telephone calls.
Results:
We studied 30 former smokers with COPD who had a mean age of 67 years and mean forced expiratory volume in 1 second (FEV1)% predicted of 60.8%. Higher AM black carbon content was associated with increased total exacerbations and severe exacerbations and reduced CD80 expression.
Conclusion:
AM black carbon association with respiratory morbidity is largely unexplored and this is the first study to identify association with prospective exacerbations. Macrophages expressed reduced CD80, a surface marker providing costimulatory signals required for development of antigen-specific immune responses. Our findings suggest that reduced CD80 expression is the pathophysiologic mechanism for the association of AM black carbon content and increased exacerbations. Therefore, beyond solely serving as a marker for increased exposures, AM black carbon content may be a predictor of future exacerbations given a macrophage less equipped to respond to an acute infectious exposure.
Insights
Black carbon in airway macrophages (AM) is linked to more frequent COPD exacerbations. This suggests AM black carbon may predict future exacerbations due to reduced immune response capabilities.
Area of Science:
- Pulmonary Medicine
- Immunology
- Environmental Health
Background:
- Chronic obstructive pulmonary disease (COPD) involves recurrent exacerbations, with macrophages crucial for immune response and tissue repair.
- Airway macrophages (AM) accumulate environmental exposures like black carbon, but its link to COPD morbidity and macrophage phenotype is unclear.
Purpose of the Study:
- To investigate the association between black carbon content in airway macrophages and COPD exacerbations.
- To explore the relationship between AM black carbon and macrophage phenotype, specifically CD80 expression.
Main Methods:
- Sputum induction was used to collect airway macrophages from former smokers with COPD.
- Macrophages were analyzed for black carbon content and underwent flow cytometry phenotyping.
- Prospective exacerbations were tracked via monthly telephone calls.
Main Results:
- Higher AM black carbon content correlated with increased total and severe COPD exacerbations.
- Increased AM black carbon was associated with reduced CD80 expression on macrophages.
Conclusions:
- This study is the first to link AM black carbon content with prospective COPD exacerbations.
- Reduced CD80 expression on macrophages may explain the association between AM black carbon and increased exacerbations.
- AM black carbon may serve as a predictor of future COPD exacerbations, indicating impaired immune response.
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