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Updated: Oct 9, 2026
Harvesting Murine Alveolar Macrophages and Evaluating Cellular Activation Induced by Polyanhydride Nanoparticles
Published on: June 8, 2012
Functional consequences for primary human alveolar macrophages following treatment with long, but not short,
Sinbad Sweeney1, Davide Grandolfo1, Pakatip Ruenraroengsak1
1Lung Cell Biology, Section of Pharmacology and Toxicology, National Heart and Lung Institute, Imperial College London, London, UK.
Purpose:
Multiwalled carbon nanotubes (MWCNTs) are a potential human health hazard, primarily via inhalation. In the lung, alveolar macrophages (AMs) provide the first line of immune cellular defense against inhaled materials. We hypothesized that, 1 and 5 days after treating AMs with short (0.6 microm in length; MWCNT-0.6 microm) and long (20 microm in length; MWCNT-20 microm) MWCNTs for 24 hours, AMs would exhibit increased markers of adverse bioreactivity (cytokine release and reactive oxygen species generation) while also having a modified functional ability (phagocytosis and migration).
Methods:
Primary human AMs were treated with short and long MWCNTs for 24 hours, 1 and 5 days after which toxicity end points, including cell death, reactive oxygen species generation, and inflammatory mediator release, were measured. AM functional end points involving phagocytic ability and migratory capacity were also measured.
Results:
AM viability was significantly decreased at 1 and 5 days after treatment with MWCNT-20 microm, while superoxide levels and inflammatory mediator release were significantly increased. At the same time, there was reduced phagocytosis and migratory capacity alongside increased expression of MARCO; this coincided with frustrated phagocytosis observed by scanning electron microscopy. In contrast, the adverse bioreactivity of the shorter MWCNT-0.6 microm with AMs (and any resulting reduction in AM functional ability) was substantially less marked or absent altogether.
Conclusion:
This study shows that after 24-hour treatment with long, but not short, MWCNTs, AM function is severely affected up to 5 days after the initial exposure. This has potentially significant pathophysiological consequences for individuals who may be intentionally (via therapeutic applications) or unintentionally exposed to these nanomaterials.
Insights
Longer multiwalled carbon nanotubes (MWCNTs) significantly impair alveolar macrophage (AM) function and viability for days. Shorter MWCNTs showed minimal adverse effects, highlighting length-dependent nanotoxicology.
Area of Science:
- Nanotoxicology
- Immunotoxicology
- Cellular Biology
Background:
- Multiwalled carbon nanotubes (MWCNTs) pose inhalation risks.
- Alveolar macrophages (AMs) are critical for lung defense against inhaled particles.
- Understanding MWCNT-AM interactions is vital for assessing health hazards.
Purpose of the Study:
- To investigate the impact of short (MWCNT-0.6 microm) and long (MWCNT-20 microm) MWCNTs on human AMs.
- To assess changes in AM bioreactivity and function post-exposure.
- To determine the duration of MWCNT-induced effects on AMs.
Main Methods:
- Human AMs were exposed to short and long MWCNTs for 24 hours.
- Toxicity markers (cell death, ROS, cytokine release) were measured at 1 and 5 days.
- Functional assays assessed phagocytosis and migration.
Main Results:
- Long MWCNTs (MWCNT-20 microm) reduced AM viability and impaired phagocytosis and migration.
- Superoxide levels and inflammatory mediators increased significantly after long MWCNT exposure.
- Short MWCNTs (MWCNT-0.6 microm) demonstrated minimal adverse effects on AMs.
Conclusions:
- Long MWCNTs severely affect AM function for up to 5 days post-exposure.
- Short MWCNTs do not significantly impair AM function.
- MWCNT length is a critical factor in nanotoxicology with potential pathophysiological implications.
