The magnetite particles are tiny, less than 150 nanometers in diameter, and smaller than a human hair, which is at least 50,000 nanometers thick. Researchers are now saying this finding provides a whole new avenue for the study of environmental factors in a number of different brain diseases.
The study was lead by Barbara Maher, a professor of environmental science at the University of Lancaster in the U.K. along with colleagues from Oxford, Glasgow, Manchester and Mexico City. Brain tissues from 37 people aged between three and 92 from Mexico City, Mexico and Manchester, U.K. were examined.
The researchers found an abundance of the magnetite particles in the frontal cortex in all of the samples — 29 from people who had lived and died in Mexico City, a notorious pollution hot-spot, and were between the ages of three and 85, and eight from Manchester. The Manchester brain tissues were from people who died between the ages of 62-92 with varying severities of neurodegenerative disease, reports the BBC.
Additionally, Professor Maher had gathered air samples beside a busy road in Manchester and near a power station, identifying the magnetite particles in the samples. “Magnetite is toxic to the human brain, and magnetite particulates are always present in pollution,” she said.
The nanoparticles they found in the brain tissue samples were strikingly similar to those particles found in air pollution. Magnetite is a mineral form of iron oxide that is toxic because of its ability to form free radicals which can cause oxidation stress inside brain cells, damaging and even killing them.
Actually, the researchers found two different forms of nanoparticles in the samples. One of the magnetite particles was angular or jagged in shape and forms naturally within the brain’s environment. Only small quantities of this type of particle are usually found.
The other particles, of which in some tissue specimens there were literally millions, were smooth and rounded, characteristic of particles created in the high temperatures of a vehicle’s engine and associated with other metals, such as platinum or cobalt and nickel.
In describing the magnetite particles, Prof Maher said: “They are spherical shapes and they have little crystallites around their surfaces, and they occur with other metals like platinum which comes from catalytic converters.”
Maher also says, “It’s a discovery finding. It’s a whole new area to investigate to understand if these magnetite particles are causing or accelerating neurodegenerative disease.” And while the study does not prove there is a link between air pollution and Alzheimer’s Disease, Maher says the potential risk is certainly worth further study.
This interesting study, “Magnetite pollution nanoparticles in the human brain,” was published in the Proceedings of the National Academy of Sciences on September 6, 2016.
