Magnetite from the environment has been found in the brain. They could also be linked to the appearance of neurodegenerative diseases.
In the American magazine Proceedings of the National Academy of Sciences (PNAS), these scientists claim to have found nanoparticles in the brains of 37 people living in Mexico City (Mexico) or Manchester (England), aged 3 to 92 years. More precisely, they are particles of magnetite, an iron oxide compound, present in a polluted environment. Because of their small size (less than 150 nanometers), they therefore penetrate the brain without difficulty.
Toxic nanoparticles
“We already knew that iron nanoparticles were present in the brain, but we thought that they came from the iron that we find naturally in the body, from food”, recalls Pr Barbara Maher, main author of the study. So how do you know that it is not the latter that have been found?
“The magnetite which is sometimes formed biologically in the brain is present there in minute quantities, and its particles are distinguished by their jagged contours,” explains the professor of environmental sciences at Lancaster University.
Quite the opposite of the particles found in the study, which were not only much more numerous, but also smooth and rounded. “These are those that are created with the high temperatures of a car engine or braking systems,” says Professor Maher. A discovery which is not without consequences for the health of lovers of the city.
This mineral form of iron is indeed considered toxic because of its ability to react easily and release other particles. These free radicals cause oxidative stress in brain cells, which can damage or even kill them.
Magnetite at the origin of Alzheimer’s
Even more worrying, two previous publications (2003 and 2008) have linked the presence of magnetite in the brain to the onset of Alzheimer’s disease. And Professor Barbara Maher suggests precisely that it could be caused by the development of these free radicals which cause damage inside the brain.
“I don’t think it can be said at this time if it causes Alzheimer’s disease, but it is a cause for concern, as magnetite particles have been linked to other health issues such as cardiovascular and pulmonary diseases”, says Peter Dobson, of King’s College London, quoted by the Science Media Center. It remains to be seen whether it is those produced naturally that promote neurodegenerative diseases or whether to look for pollution.
