Researchers at Lancaster University have discovered tiny magnetic particles from air pollution present in human brains, which they claim could be a potential cause of Alzheimers disease.
Examining 37 individuals aged between three to 92-years-old from Mexico City or Manchester, the researchers found abundant magnetic nanoparticles in brain tissue that they claim shouldnt be there.
This strongly magnetic mineral is toxic and causes the formation of reactive oxygen species in the human brain, which cause cell damage and death and as such are associated with neurodegenerative diseases including Alzheimers disease, the researchers said.
Professor Barbara Maher, from Lancaster Environment Centre, together with colleagues from Oxford, Glasgow, Manchester and Mexico City, used spectroscopic analysis to identify the particles as magnetite.
Unlike angular magnetite particles that are believed to form naturally within the brain, most of the observed particles were spherical, with diameters up to 150 nm, some with fused surfaces, all characteristic of high-temperature formation such as from vehicle (particularly diesel) engines or open fires.
The spherical particles are often accompanied by nanoparticles containing other metals, such as platinum, nickel, and cobalt.
Professor Maher said: The particles we found are strikingly similar to the magnetite nanospheres that are abundant in the airborne pollution found in urban settings, especially next to busy roads, and which are formed by combustion or frictional heating from vehicle engines or brakes.
Other sources of magnetite nanoparticles include open fires and poorly sealed stoves within homes. Particles smaller than 200 nm are small enough to enter the brain directly after breathing air pollution through the nose.
Our results indicate that magnetite nanoparticles in the atmosphere can enter the human brain, where they might pose a risk to human health, including conditions such as Alzheimers disease, added Professor Maher.
Professor Maher added the research doesnt yet prove a cause link between these particles in the atmosphere and Alzheimers disease, but its a potential environmental risk factor that we cant afford to ignore.
Leading Alzheimers researcher Professor David Allsop, of Lancaster Universitys Faculty of Health and Medicine, said: This finding opens up a whole new avenue for research into a possible environmental risk factor for a range of different brain diseases.
The results have been published in the paper Magnetite pollution nanoparticles in the human brain by the Proceedings of the National Academy of Sciences.