Cross-disciplinary geoscience provides key link in dementia understanding

Postdoctoral researcher Dr Imad Ahmed has been pushing the frontiers of geoscience by providing experimental analysis for one of modern medicine’s most pressing problems: the cause of degenerative brain disease.

In a paper published in the journal Proceedings of the National Academy of Sciences, Dr Ahmed analysed tiny samples of magnetite which could provide a key link to a range of neurodegenerative disorders, such as dementia, Alzheimer’s and epilepsy.

The research, led by Professor Barbara Maher at Lancaster University, looked at patients with abundant magnetite nanoparticles in their brain tissue. These toxic particles have been implicated in the production of reactive oxygen species (free radicals) in the human brain, but had previously been thought to occur naturally. Dr Ahmed’s analysis suggested otherwise. This finding follows more than two decades since the first discovery of biogenic magnetite in human brains by Joseph Kirschvink at Caltech University.

‘Using high-resolution transmission electron microscopy, electron energy loss spectroscopy and electron diffraction, we were able to show the presence of extremely tiny crystals having the “unmistakable signature” of magnetite, with sizes ranging from ~10 nm up to 150 nm in diameter. The vast majority of the observed particles were spherical, a key distinction from angular biogenic magnetite that are believed to form naturally in the brain and other organs,’ Dr Ahmed explains.

‘The amazing thing is that the discovered particles have almost the same shape and surface texture of magnetic particles formed during high-temperature combustion of fossil fuels used in car engines, power stations, or even in the smelting industry. The identification of transition elements associated with the crystal structure of brain magnetites, particularly platinum, provides convincing evidence of the high-temperature and pollution origin of these nano-particles.’

Dr Ahmed believes that the identification of pollution-derived brain magnetites has been delayed for years mainly because of the difficulty of isolating the magnetic particles without the introduction of metallic contamination or artefacts during the experiments. One of Dr Ahmed’s key contributions to this research was the development of an experimental system for the isolation of nano-magnetites from brain tissues under strictly inert and clean conditions, helping the tiny particles to maintain their structural and chemical identities.

‘While it is still debated whether the response of the brain magnetities to external magnetic fields can cause health damage,’ Dr Ahmed stresses, ‘due to their much larger surface area to unit mass ratio and for their strong electrochemical properties, brain magnetites can potentially cause not only oxidative damage to brain tissues but also alteration of the chemistry of the cerebrospinal fluid leading to cognitive decline, memory loss or other dementia-related disorders.

‘As an earth scientist, I enjoy studying the geochemical properties and processes of the earth but I find it even more fascinating to use that knowledge to understand our geochemical origins, as well as the health impacts of environmental exposure.’

You can read more about this story on the University of Oxford news page.

An article on this paper appeared in The Telegraph.

Read Dr Ahmed’s Academic Research Profile

Paper: Magnetite pollution nanoparticles in the human brain, by Barbara A. Maher, Imad A. M. Ahmed, Vassil Karloukovski, Donald A. MacLaren, Penelope G. Foulds, David Allsop, David M. A. Mann, Ricardo Torres-Jardón, and Lilian Calderon-Garciduenas was published in Proceedings of the National Academy of Sciences