Study reports link between exposure to magnetite particles and Alzheimer's disease symptoms

Magnetite, a tiny particle found in air pollution, may trigger signs and symptoms of Alzheimer's disease, new research suggests.

Alzheimer's disease, a type of dementia, causes memory loss, decline in cognitive function, and a significant decline in quality of life. It affects millions of people worldwide and is the leading cause of death in the elderly.

A study led by Associate Professor Cindy Gunawan and Associate Professor Christine McGrath from the University of Technology Sydney (UTS), 'Neurodegenerative effects of air pollutant particles: biological mechanisms associated with early-onset Alzheimer's disease', was recently published. environment international.

A research team from UTS, UNSW Sydney and Singapore Agency for Science, Technology and Research investigated the effects of air pollution on the brain health of mouse and human neurons in the laboratory.

Their aim was to better understand how exposure to toxic air pollution particles can cause Alzheimer's disease.

Associate Professor Gunawan, from the Australian Institute of Microbiology and Infectious Diseases (AIMI), said: “Less than 1% of Alzheimer's cases are inherited, so environment and lifestyle may play an important role in the development of Alzheimer's disease. “It's very sexual,” he said.

“Previous research has shown that people who live in areas with high air pollution levels are at increased risk of developing Alzheimer's disease. Magnetite, a magnetic iron oxide compound, is also found in large amounts in the brains of Alzheimer's patients. has been detected.

“But this is the first study to examine whether the presence of magnetite particles in the brain can actually cause signs of Alzheimer's disease,” she said.

Researchers exposed healthy mice and mice genetically predisposed to Alzheimer's disease to very fine particles of iron, magnetite, and diesel hydrocarbons for four months. They found that magnetite induced the most consistent Alzheimer's disease pathology.

This includes the loss of neurons in the hippocampus, an area of ​​the brain important for memory, and the somatosensory cortex, an area that processes sensations from the body. Mice already predisposed to Alzheimer's disease showed increased formation of amyloid plaques.

The researchers also observed behavioral changes in mice consistent with Alzheimer's disease, such as increased stress and anxiety and impaired short-term memory, the latter especially in genetically predisposed mice.

Magnetite is a very common air pollutant. This is caused by high-temperature combustion processes such as vehicle exhaust, wood fires, and coal-fired power plants, as well as brake pad friction and engine wear. ”

Kristine McGrath, Associate Professor, Faculty of Life Sciences, UTS

“When we breathe in air pollutants, these magnetite particles enter the brain through the lining of the nasal cavity, bypass the blood-brain barrier through the olfactory bulb, a small structure at the base of the brain responsible for processing smells, and ” she said.

Researchers found that magnetite elicited an immune response in nerve cells in mice and humans in the lab. It causes inflammation and oxidative stress, causing cell damage. Inflammation and oxidative stress are important factors known to contribute to dementia.

“Magnetite-induced neurodegeneration is also independent of pathology, and the brains of healthy mice show signs of Alzheimer's disease,” said co-first author Dr Charlotte Fleming from the UTS School of Life Sciences.

The results will be of interest to health professionals and policy makers. It suggests that people should take steps to reduce their exposure to air pollution as much as possible and consider ways to improve air quality and reduce the risk of neurodegenerative diseases.

This research has implications for air pollution guidelines. Magnetite particles should be included in the recommended safety thresholds for air quality indices, as well as increased measures to reduce vehicle and coal-fired power plant emissions.