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Olfactory deposition of inhaled nanoparticles in humans. Inhal Toxicol 2015;27(8):394-403

Date

07/22/2015

Pubmed ID

26194036

Pubmed Central ID

PMC4745908

DOI

10.3109/08958378.2015.1066904

Scopus ID

2-s2.0-84939235361   51 Citations

Abstract

CONTEXT: Inhaled nanoparticles can migrate to the brain via the olfactory bulb, as demonstrated in experiments in several animal species. This route of exposure may be the mechanism behind the correlation between air pollution and human neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease.

OBJECTIVES: This article aims to (i) estimate the dose of inhaled nanoparticles that deposit in the human olfactory epithelium during nasal breathing at rest and (ii) compare the olfactory dose in humans with our earlier dose estimates for rats.

MATERIALS AND METHODS: An anatomically-accurate model of the human nasal cavity was developed based on computed tomography scans. The deposition of 1-100 nm particles in the whole nasal cavity and its olfactory region were estimated via computational fluid dynamics (CFD) simulations. Our CFD methods were validated by comparing our numerical predictions for whole-nose deposition with experimental data and previous CFD studies in the literature.

RESULTS: In humans, olfactory dose of inhaled nanoparticles is highest for 1-2 nm particles with ∼1% of inhaled particles depositing in the olfactory region. As particle size grows to 100 nm, olfactory deposition decreases to 0.01% of inhaled particles.

DISCUSSION AND CONCLUSION: Our results suggest that the percentage of inhaled particles that deposit in the olfactory region is lower in humans than in rats. However, olfactory dose per unit surface area is estimated to be higher in humans in the 1--7 nm size range due to the larger inhalation rate in humans. These dose estimates are important for risk assessment and dose-response studies investigating the neurotoxicity of inhaled nanoparticles.

Author List

Garcia GJ, Schroeter JD, Kimbell JS

Author

Guilherme Garcia PhD Assistant Professor in the Biomedical Engineering department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Adult
Animals
Computer Simulation
Disease Models, Animal
Female
Humans
Hydrodynamics
Inhalation Exposure
Male
Middle Aged
Models, Anatomic
Nanoparticles
Nasal Cavity
Nose
Olfactory Bulb
Olfactory Mucosa
Particle Size
Rats
Rats, Inbred F344
Reproducibility of Results
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a