Do inhaled carbon nanoparticles translocate directly into the circulation in humans?

Mills, N. L. et al. (2006) Do inhaled carbon nanoparticles translocate directly into the circulation in humans? American Journal of Respiratory and Critical Care Medicine, 173(4), pp. 426-431. (doi: 10.1164/rccm.200506-865OC)

Abstract

Rationale: Increased exposure to particulate air pollution (PM₁₀) is a risk factor for death and hospitalization with cardiovascular disease. It has been suggested that the nanoparticulate component of PM₁₀ is capable of translocating into the circulation with the potential for direct effects on the vasculature..

Objective: The study's aim was to determine the extent to which inhaled technetium-99m (^99mTc)–labeled carbon nanoparticles (Technegas) were able to access the systemic circulation..

Methods and Main Results: Ten healthy volunteers inhaled Technegas and blood samples were taken sequentially over the following 6 h. Technegas particles were 4–20 nm in diameter and aggregated to a median particle diameter of approximately 100 nm. Radioactivity was immediately detected in blood, with levels increasing over 60 min. Thin-layer chromatography of whole blood identified a species that moved with the solvent front, corresponding to unbound ^99mTc-pertechnetate, which was excreted in urine. There was no evidence of particle-bound ^99mTc at the origin. γ Camera images demonstrated high levels of Technegas retention (95.6 ± 1.7% at 6 h) in the lungs, with no accumulation of radioactivity detected over the liver or spleen..

Conclusions: The majority of ^99mTc-labeled carbon nanoparticles remain within the lung up to 6 h after inhalation. In contrast to previous published studies, thin-layer chromatography did not support the hypothesis that inhaled Technegas carbon nanoparticles pass directly from the lungs into the systemic circulation.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Davies, Professor John
• Authors: Mills, N. L., Amin, N., Robinson, S. D., Anand, A., Davies, J., Patel, D., de la Fuente, J. M., Cassee, F. R., Boon, N. A., MacNee, W., Millar, A. M., Donaldson, K., and Newby, D. E.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: American Journal of Respiratory and Critical Care Medicine
• Publisher: American Thoracic Society
• ISSN: 1073-449X
• ISSN (Online): 1535-4970