This Article Full Text Full Text (PDF) Online Supplement All Versions of this Article: 200602-301OCv1 177/4/426    most recent Alert me when this article is cited Alert me if a correction is posted Services Related articles in AJRCCM Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Möller, W. Articles by Kreyling, W. G. Search for Related Content PubMed PubMed Citation Articles by Möller, W. Articles by Kreyling, W. G.

Deposition, Retention, and Translocation of Ultrafine Particles from the Central Airways and Lung Periphery

¹ Inflammatory Lung Diseases Clinical Cooperation Group, Institute for Inhalation Biology, and Aerosols and Health Focus Network, GSF-National Research Center for Environment and Health, Gauting and Neuherberg, Germany; ² Inamed Research GmbH, Gauting, Germany; and ³ Asklepios Hospital for Respiratory Diseases, Gauting, Germany

Correspondence and requests for reprints should be addressed to Dr. Winfried Möller, Ph.D., GSF–National Research Center for Environment and Health Institute for Inhalation Biology, Robert Koch Allee 29, D-82131 Gauting, Germany. E-mail: moeller{at}gsf.de

Rationale: Little is known about clearance of ultrafine carbon particles from the different regions of the human lung. These particles may accumulate and present a health hazard because of their high surface area.

Objectives: Technetium Tc 99m (^99mTc)–radiolabeled 100-nm-diameter carbon particles were inhaled by healthy nonsmokers, asymptomatic smokers, and by patients with chronic obstructive pulmonary disease (COPD).

Methods: Using a bolus inhalation technique, particle deposition was targeted either to the airways or to the lung periphery, and retention, clearance, and translocation were measured using retained radiotracer imaging.

Measurements and Main Results: In vitro studies revealed that mean leaching of soluble ^99mTc-radiotracer from the carbon particles was 4.1 (2.6 [SD]) % after 24 hours. Cumulative ^99mTc activity in urine at 24 hours was 1.1 (1.3) % of activity deposited in the lungs. In the lung periphery, particle retention was not affected by smoking or pulmonary disease; retention was 96 (3) % after 24 hours. The small amount of clearance could be attributed to leaching of the ^99mTc label, suggesting negligible particle clearance. In healthy nonsmokers, retention of particles targeted to the airways was 89 (6) and 75 (10) % after 1.5 and 24 hours, respectively. Radiolabel activity did not accumulate in the liver.

Conclusions: Within the limits of detection of our experimental system, most inhaled ultrafine carbon particles are retained in the lung periphery and in the conducting airways without substantial systemic translocation or accumulation in the liver at 48 hours. Repeated exposure may result in significant pulmonary accumulation of ultrafine particles.

Key Words: air pollution • clearance • translocation • ultrafine particles

AT A GLANCE COMMENTARY Scientific Knowledge on the Subject It has been suggested that ultrafine particles may play a key role in the morbidity and mortality of inhaled air pollution. The fate of inhaled ultrafine particles in the different regions of the human lung is unclear and systemic translocation to other organs, such as the liver or the heart, is under debate. What This Study Adds to the Field Inhaled ultrafine carbon particles are retained long term in the human lung and may accumulate. Mucociliary clearance does not remove all particles deposited in the airways and is impaired in smokers and in patients with chronic obstructive pulmonary disease. Our study does not show significant systemic translocation.

 

Related articles in AJRCCM:

Reducing Exposure to Airborne Particles: A Novel Strategy to Improve Cardiovascular Health

Nicholas L. Mills, Günter Oberdörster, and David E. Newby
AJRCCM 2008 177: 366-367. [Full Text]  

This article has been cited by other articles:

				N. L. Mills, G. Oberdorster, and D. E. Newby Reducing Exposure to Airborne Particles: A Novel Strategy to Improve Cardiovascular Health Am. J. Respir. Crit. Care Med., February 15, 2008; 177(4): 366 - 367. [Full Text] [PDF]