Researchers from the University of Technology Sydney (UTS), UNSW Sydney, and the Agency for Science, Technology and Research in Singapore have found a link between air pollution and Alzheimer’s disease
The study explains how tiny particles in air pollution, particularly magnetite, may induce signs and symptoms of Alzheimer’s disease.
Is environmental health worsening Alzheimer’s disease?
Alzheimer’s disease, a form of dementia characterised by memory loss and cognitive decline, affects millions worldwide and stands as a leading cause of death in older individuals.
While genetics play a role in less than 1% of Alzheimer’s cases, environmental factors, including air pollution, are increasingly recognised as significant contributors to the disease’s development.
The research team conducted experiments on mice and human neuronal cells in laboratory settings to understand the impact of air pollution particles on brain health. Over four months, healthy mice and those genetically predisposed to Alzheimer’s were exposed to fine particles of iron, magnetite, and diesel hydrocarbons.
“Fewer than 1% of Alzheimer’s cases are inherited, so it is likely that the environment and lifestyle play a key role in the development of the disease,” said Associate Professor Gunawan
“However, this is the first study to look at whether the presence of magnetite particles in the brain can indeed lead to signs of Alzheimer’s,” she said.
The unknown health concerns of air pollution
Their findings revealed that magnetite, a magnetic iron oxide compound commonly found in air pollution, consistently caused Alzheimer’s disease pathologies in the mice. The presence of magnetite led to the loss of neuronal cells in key brain regions responsible for memory and sensory processing. An increased amyloid plaque formation was observed in mice genetically predisposed to the condition.
Behavioural changes indicative of Alzheimer’s disease, such as increased stress, anxiety, and short-term memory impairment, were also noted in the exposed mice. Associate Professor McGrath highlighted that magnetite, originating from various combustion processes, including vehicle exhaust and coal-fired power stations, can enter the brain through the nasal passage and olfactory bulb, bypassing the protective blood-brain barrier.
The study found that magnetite triggered an immune response and inflammation in both mice and human neuronal cells, leading to oxidative stress and cell damage. These findings highlight the significant role of inflammation and oxidative stress in contributing to neurodegenerative diseases like Alzheimer’s.
“Fewer than 1% of Alzheimer’s cases are inherited, so it is likely that the environment and lifestyle play a key role in the development of the disease,”
Improving air quality
The research has implications for public health policies and air quality guidelines. Associate Professor Gunawan emphasised the need to reduce exposure to air pollution, particularly magnetite particles, to mitigate the risk of Alzheimer’s disease. She suggested implementing measures to improve air quality and reduce emissions from vehicles and coal-fired power stations.
