by Zadie Neufville
The following was published in Spanish by SciDev.com
Researchers at UK’s University of Lancaster have found toxic nanoparticles similar to that associated with Alzheimer’s disease could come from industrial air pollution which may enter the brain by the nasal passage, suggesting a new environmental risk factor in neurodegenerative diseases.
Traces of magnetite, a magnetic iron oxide compound and a very common air pollutant, are known to be present naturally in human brain and derived from the iron used in normal brain function.
According to the study published in the Proceedings of the National Academy of Sciences (PNAS) on Sept 5, researchers measured magnetic samples and examined their sizes and shape to determine the source of the particles.
In analysing brain tissues from 37 people in Manchester, England, and Mexico City, aged between 3 years old and 92, the researchers observed that most of the magnetite particles were rounded small nonosphere (ranged from less than 5 nanometers to more than 100 nanometers), while biological magnetite are angular crystals and with a diameter from 50 to 150 nanometers.
The shape responds to the origin of the particles, “because they were formed as molten droplets of material from combustion sources, such as car exhausts, industrial processes, open fires,” Barbara Maher, lead author of the study, told SciDev.Net.
In the study, researchers also detected other metal particles like platinum, cobalt and nickel, and since none of them occurs naturally in the brain, their findings suggest that those particles could come from motor vehicle exhaust.
“Scientists have always believed the metal was formed in the body. The surprise is finding that they can enter the brain via inhalation,” Maher said.
Earlier studies suggested possible links between high levels of toxic magnetite in the brains of people who lived in highly polluted areas and Alzheimers disease and dementia. She noted: “These findings do not particularly prove that air pollution will cause brain diseases”.
“We need to do more work to see if this is a cause of brain disease,” Maher added.
According to the World Health Organisation (WHO) air pollution kills 1.3 million people globally each year.
Denise Eldemire-Shearer, a professor at the University of the West Indies, said the study raised the need for critical research given the “ageing populations and the increased importance of dementia research, the cost and the possible associated social costs”.
“We look forward to the wider study”, she said noting that the numbers of the individuals involved in the study were small.
Link to PNAS study