A team of scientists in France have discovered traces of the carbon material known as carbon nanotubes (CNT) in the airways of children with asthma, raising concerns about potential risks they pose on human health.
In a study featured in the journal EBioMedicine, researchers at the University of Paris-Saclay found evidence of CNTs in the fluid taken from 64 French children diagnosed with asthma. The team also discovered the synthetic material in the macrophages, or the immune cells responsible for removing foreign objects in the lungs, of five other youngsters observed.
While the researchers have yet to determine the level of nanotubes present in the lungs of the children as well as the source, they have detected similar structures of the material in vehicle exhaust and dust collected in different parts of Paris.
"Compelling evidence shows that fine particulate matters (PMs) from air pollution penetrate lower airways and are associated with adverse health effects even within concentrations below those recommended by the WHO," the abstract of the study reads.
Lead researcher Fathi Moussa explained that the study was not intended to establish a potential connection between the presence of carbon nanotubes in lungs of the children and their health condition, but asthmatic patients could be particularly at risk as the ability of macrophages in their bodies to remove unwanted materials is impaired.
Despite not being toxic objects on their own, carbon nanotubes feature large surface areas, which other molecules could stick to. Moussa said that these could possibly help pollutants to penetrate the lungs deeper and affect cell membranes.
Potential Health Risks of Carbon Nanotubes
Carbon nanotubes are often used in the production of computers, clothing and technologies for healthcare because of the material's highly durable and conductive properties.
However, scientists have identified that the synthetic material can trigger immune reactions in individuals that resemble the effects of asbestos.
British researcher Ken Donaldson and his colleagues at the University of Edinburgh introduced carbon nanotubes with multiple walls into the abdominal cavity of laboratory mice. After seven days, they discovered that the animals developed severe immune reactions to the materials.
Lesions called granulomas were also observed in the surrounding tissues of the mice's abdominal organs.
Granulomas typically form when macrophages absorb and neutralize foreign objects in the lungs. These immune cells rupture when they try to take in particles with fibers beyond 20 micrometers in length.
North Carolina State University researcher James Bonner, who is not involved in the University of Paris-Saclay and the University of Edinburgh, pointed out that nanotube detection should be carried out with caution as earlier air pollution studies were not able to identify the synthetic material.
"In my opinion, there is a great deal of uncertainty as to what these structures really are, especially the material in the lung cells from patients," Bonner said.
Photo: Moyan Brenn | Flickr