Figure 1.

Smokers and vapers show increased lipid deposition in alveolar macrophages. BAL samples were collected from healthy nonsmokers, smokers, and vapers to obtain the alveolar macrophages and secreted proteins. Cytospin slides were prepared and Oil Red O stain was used to identify intracellular lipid deposition in alveolar macrophages. The representative images of Oil Red O staining in nonsmokers, smokers, and vapers are shown with positively stained macrophages marked with arrows. The graphs show the percentage of cells with positive staining for lipid deposition per subject. The cytospin slides from smokers (n = 19) and vapers (n = 15) had significantly higher numbers of Oil Red O–positive macrophages than the nonsmokers (n = 9). A regression analysis of available serum cotinine concentrations with the percentage of LLMs showed a strong correlation (R = 0.65). The pink dots are female subjects and the blue dots are male subjects. Tukey’s post hoc test derived the P values that are provided on the graphs. LLMs = lipid-laden macrophages; Macs = macrophages; NS = nonsignificant.