Particles found in air pollution are linked to Alzheimer’s disease, according to the results of a new study by the University of Technology Sydney (UTS) and others in Australia and in Singapore.
Alzheimer’s disease
Alzheimer’s is a neurodegenerative disease that impairs memory, as well as cognitive and eventually bodily functions. It is estimated to be the reason behind 60-70% of dementia cases. With very few Alzheimer’s cases thought to be hereditary, less than 1%”, according to co-lead author Associate Professor Cindy Gunawan, science is turning its attention to “environment and lifestyle choices [that] seem to have a major impact on the disease”.
First study of magnetite
With that in mind, the researchers followed the trail of previous work linking air pollution and Alzheimer’s. They looked at the effects of various air pollutants, including iron, magnetite, and diesel hydrocarbons, on the brain health of healthy and susceptible mice over a four-month study. It is the first study of its kind to focus on magnetite.
A common air pollutant emitted by a range of processes from brake pad friction and engine wear to coal-fired power stations, vehicle exhaust emissions, and wood fires, magnetite was found to create effects consistent with Alzheimer’s, including loss of brain cells, amyloid plaque, and behavioural changes such as heightened anxiety, stress and short-term memory problems. In both mice and human cells, magnetite sparks an immune response, which results in inflammation and oxidative stress. These are known to play a part in dementia.
Magnetite seems to cause neurodegeneration even in healthy mice, a concerning finding.
Dr. Charlotte Fleming, study co-author
Particles enter the brain directly
The problem with the tiny particles of magnetite created by combustion, is that they can enter the brain directly thought the nose, so the human blood brain barrier is no defence against them. “We breathe in these particles,” said co-lead author Associate Professor Kristina McGrath, adding “they have the troubling ability to enter the brain through our nasal passages, sidestepping the protective blood-brain barrier.”
Monitoring and awareness
Fleming points out the implication “that anyone who is exposed to magnetite particles in the air could potentially develop Alzheimer’s disease, regardless of their genetic background or other risk factors.” As a result, she argues “it is vital to monitor and regulate the levels of magnetite in the air, and to raise awareness of the potential health hazards of air pollution.”
