COPD Has Altered Deposition of Inhaled Nanoparticles

A lower deposition fraction of nanoparticles was seen in the distal lung in patients with chronic obstructive pulmonary disease (COPD) than in healthy individuals during a breath-hold, according to a study published in BMC Pulmonology Medicine.

Researchers contended that this can be explained by the enlarged distal airspaces associated with emphysema and indicates that lung morphology significantly influences the deposition of nanoparticles.

The researchers measured lung deposition of nanoparticles between 50 and 100 nm after a 10-second breath-hold in 3 groups: healthy, never-smokers; asymptomatic current and former smokers; and individuals with COPD. The investigators took measurements at 1300 mL and 1800 mL volumetric lung depth. They conducted conventional lung function tests in all participants, including postbronchodilator forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and diffusing capacity for carbon monoxide (D_LCO). Patients with respiratory disease also underwent computed tomography (CT) lung scan.

A total of 48 participants completed the study. In patients with emphysema, deposition fraction was significantly lower than in other individuals, but no significant differences were found between healthy never smokers and current or former smokers. The investigators also found a correlation between lung function tests, FEV_1%pred (P <.05), FEV₁/FVC_%pred (P <.01) and D_LCO (P <.0005), and particle deposition within the total trial population. In patients with emphysema, the deposition fraction showed a strong correlation with D_LCO (Pearson’s r=0.80-0.85, P <.002).

The authors proposed that the results of this study suggest that measurement of lung deposition of nanoparticles may be used to determine the presence and extent of respiratory disease. They further noted that the medical significance of this information may be similar to magnetic resonance imaging with hyperpolarized noble gas.

“[L]ung morphology… should be considered when estimating the lung burden of airborne particles, when identifying especially vulnerable groups, and in dosimetry of aerosol-based drug administration,” the researchers concluded.

Reference

Jakobsson JKF, Aaltonen HL, Nicklasson H, et al. Altered deposition of inhaled nanoparticles in subjects with chronic obstructive pulmonary disease. BMC Pulmon Med. 2018;19:129. doi:10.1186/s12890-018-0697-2