Smoking decreases alveolar macrophage function during anesthesia and surgery

Area of Science:

• Pulmonary immunology
• Anesthesiology
• Surgical complications

Background:

• Smoking is a major risk factor for postoperative pulmonary complications.
• Alveolar macrophage function is altered by smoking.
• The impact of smoking on immune responses during anesthesia is not fully understood.

Purpose of the Study:

• To test the hypothesis that smoking impairs antimicrobial and proinflammatory responses in alveolar macrophages during anesthesia and surgery.
• To investigate the effect of smoking on macrophage function and cytokine expression in patients undergoing surgery.

Main Methods:

• Studied 30 smokers and 30 nonsmokers under propofol-fentanyl general anesthesia.
• Harvested alveolar immune cells via bronchoalveolar lavage at multiple time points.
• Measured phagocytosis, microbicidal activity, and gene expression of key proinflammatory cytokines (IL-1β, IL-6, IL-8, IFN-γ, TNF-α).

Main Results:

• Macrophage aggregation increased over time in both groups, but phagocytosis and microbicidal activity decreased significantly more in smokers.
• Gene expression of most proinflammatory cytokines increased in both groups, but less so in smokers for IL-1β, IFN-γ, and TNF-α.
• Smokers exhibited nearly twice the reduction in phagocytic and microbicidal activity compared to nonsmokers.

Conclusions:

• Smoking is associated with impaired alveolar macrophage phagocytic and microbicidal activity post-anesthesia and surgery.
• Reduced expression of proinflammatory cytokines in smokers may contribute to impaired pulmonary immune defense.
• Smokers may have a limited ability to mount an effective pulmonary immune response after anesthesia and surgery.