Marijuana smoking, pulmonary function, and lung macrophage oxidant release

Area of Science:

• Pulmonary immunology
• Respiratory toxicology
• Environmental health

Background:

• Pulmonary alveolar macrophages from tobacco smokers release excess oxidants, contributing to emphysema.
• The effect of marijuana smoking on lung macrophage oxidant release and lung function is largely unknown.

Purpose of the Study:

• To investigate whether lung macrophages from marijuana smokers release excessive oxidants.
• To correlate oxidant release with lung function in different smoking groups.

Main Methods:

• Pulmonary alveolar macrophages were obtained via bronchoalveolar lavage from non-smokers, marijuana-only smokers, tobacco-only smokers, and dual smokers.
• Spontaneous and stimulated superoxide anion release was measured.
• Lung function tests assessed small airway integrity and alveolar gas exchange.

Main Results:

• Macrophages from marijuana-only smokers exhibited similar superoxide anion production to non-smokers.
• Tobacco smokers (both only and dual) showed significantly higher macrophage superoxide anion release.
• Tobacco smoking correlated with impaired small airway function and reduced diffusing capacity for carbon monoxide.

Conclusions:

• Pulmonary alveolar macrophages from marijuana-only smokers do not produce increased oxidants compared to non-smokers.
• This lack of increased oxidant production may explain the absence of lung function abnormalities in marijuana-only smokers.
• Tobacco smoking, irrespective of marijuana use, is associated with increased macrophage oxidant release and lung function deficits.