New research reveals dirty air is affecting the brains of young people. The tiny air pollution particles inhaled make their way up to the brainstem, where they accumulate.
The scientists found that the brainstems of children and young adults exposed to constant, lifelong air pollution in Mexico City have damage similar to Alzheimer’s Disease, motor neurone disease, and Parkinson’s Disease. There is evidence of growths, plaques, and tangles associated with those diseases. The global implications of this discovery, if confirmed, are grim since 90% of the world’s population is breathing dirty air.
Prof Barbara Maher, at Lancaster University, and part of the research team, said:
It is terrifying because, even in infants, there is neuropathology in the brain stem. We can’t prove causality so far, but how could you expect these nanoparticles containing those metal species to sit inert and harmless inside critical cells of the brain? That’s the smoking gun – it seriously looks as if those nanoparticles are firing the bullets that are causing the observed neurodegenerative damage.
Higher exposure to air pollution has already been linked to glaucoma, lung and heart problems, and damage to every organ in the body. However, this discovery is different because it shows a possible physical mechanism by which the damage is done.
Dr. Susan Kohlhaas, Alzheimer’s Research UK’s director of research, said:
Air pollution is linked to many adverse health conditions, and a growing body of evidence suggests this includes our risk of developing dementia. Proteins do build up in the brain years before we see visible dementia symptoms.
The particles may increase oxidative stress, eventually leading to neurons’ death, considering the way they reacted with the brain cells. Neuron damage in the brain stem is a common feature of Parkinson’s disease (the fastest-growing neurological condition worldwide) and some forms of MND.
The brainstem regulates the central nervous system and controls our perception of position, our body’s movement, our sense of balance, and even our breathing rates and heart.
The Lancaster University scientists analyzed the brains of 186 young people (between 11 months and 27 years old) that had died. They found abundant pollution nanoparticles (likely from vehicles) in all their brainstems coupled with abnormal proteins. The brains of people from less polluted regions did not have aberrant proteins.
Prof Maher explained:
Not only did the brainstems of the young people in the study show the ‘neuropathological hallmarks’ of Alzheimer’s, Parkinson’s and MND, they also had high concentrations of iron-, aluminum- and titanium-rich nanoparticles in the brainstem – specifically in the substantia nigra, and cerebellum.
The iron-and aluminum-rich nanoparticles found in the brainstem are strikingly similar to those which occur as combustion- and friction-derived particles in air pollution (from engines and braking systems). The titanium-rich particles in the brain were different – distinctively needle-like in shape; similar particles were observed in the nerve cells of the gut wall, suggesting these particles reach the brain after being swallowed and moving from the gut into the nerve cells which connect the brainstem with the digestive system.
Previous work by the same team found pollution nanoparticles in the hearts and frontal cortex of young people’s brains. Meanwhile, researchers in China have seen them in blood.
Air pollution is a global silent pandemic, killing more people from diabetes, high blood pressure, stroke, and heart attack than war and many diseases. With all the accumulating evidence tying dirty air to dementia and cognitive impairment, you can also add deaths by neurological disorders to the list.
And this isn’t the first time air pollution has been linked to young people and health problems. Recently, a study found that adolescents living in cities with high air pollution have a higher risk of asthma, psychotic experiences, schizophrenia, and suicide.
Prof Maher told Science Alert:
(O)ur new findings indicate that what air pollutants you are exposed to, what you are inhaling and swallowing, are really significant in the development of neurological damage.
The next phase of the research is to prove that the nanoparticles cause brain damage and how it happens. For now, the findings are still premature to confirm that air pollution directly leads to the development of cognitive disease.
