Enhanced adverse health effects upon in vivo exposure to multi-walled carbon nanotubes in chronic obstructive pulmonary disease

Objectives: With progress of nanotechnology there is increasing concern about possible adverse health-effects of inhaled occupational nanoparticles, such as multi-walled carbon nanotubes (MWCNTs), particularly in the respiratory tract in persons suffering from chronic obstructive pulmonary disease (COPD). Methods: We utilized an Elastase/LPS COPD mouse model in which healthy controls and COPD animals received 0.08µg/cm 2 of MWCNTs by intratracheal instillation. Lung function, morphometry, differential counts of the bronchoalveolar lavage fluid, as well as the phenotype and activation of alveolar macrophages (AM) and dendritic cells (DC) were monitored in the respiratory tract by flow cytometry. Results: All AM and DC populations monitored displayed an activated surface phenotype (CD40; CD80) upon exposure to MWCNTs in both healthy and COPD mice. Differential counts revealed a fiber-related AM increase that was more pronounced in the COPD group. Frequencies of DC following MWCNT exposure were increased in both healthy controls and COPD mice. Also, exposure to MWCNTs caused an increase in both AM polarization markers CD38 (M1-like) and CD206 (M2-like). In healthy and COPD animals measurements of the lung function revealed a pronounced reduction in tissue elasticity in COPD animals, although this was not altered by MWCNTs. Conclusions: Employing a COPD mouse model, we demonstrated fiber-related changes in pulmonary macrophage and dendritic cell populations with an increased effect of MWCNTs seen in the presence of COPD.