Diesel exhaust can increase your risk of developing Parkinson’s disease, study says
Air pollution is commonly associated with breathing problems and even some heart conditions, but new research adds to speculations that traffic-related pollution can contribute to Parkinson’s disease by damaging brain cells.
With the help of some zebrafish and human cells on a dish, the study sheds light on how diesel exhaust can increase the risk of neurodegenerative disease and emphasizes the need to reduce exposure to harmful environmental chemicals.
The peer-reviewed paper was published in April in the journal Toxicological Sciences.
“It’s really important to be able to demonstrate whether air pollution is actually the thing that’s causing the effect or whether it’s something else in urban environments,” Dr. Jeff Bronstein, study author and neurology professor at the University of California, Los Angeles, said in a press release.
Parkinson’s disease is a brain disorder linked to shaking, walking difficulty, stiffness and a lack of coordination, according to the National Institute of Aging.
Symptoms usually appear around age 60 and are often the result of inherited gene mutations. But several studies over the years have suggested that air pollution plays a role, too.
Chemicals expelled from a car’s exhaust system include a mixture of thousands of gases that can contain more than 40 toxic air pollutants such as benzene, carbon dioxide, nitrogen oxide and arsenic, the California Office of Environmental Health Hazard Assessment said.
When inhaled, they can irritate the eyes, throat and lungs, causing anything from headaches to cancer, depending on the duration of exposure.
To test the theory, the team added some chemicals found in diesel exhaust into a tank of freshwater with zebrafish: a species with neurons that function similarly to those in human brains, according to the researchers from the department of neurology in the David Geffen School of Medicine at UCLA.
The fish are also transparent, making it easier to “measure biological processes without killing the animals,” the news release said.
What happened?
In addition to changed behavior, the zebrafish brains experienced a disruption in autophagy —a process that cleans out “old or damaged proteins” in the body —which is a telltale sign of Parkinson’s disease in people, the news release said.
This “toxic accumulation” of old proteins eventually killed neurons in the fishes’ brains, the study said.
This brain cell death leads to tremors and muscle stiffness commonly seen in people with the disease.
To confirm that the diesel exhaust caused the cell death, the researchers gave the fish a drug that boosts the cleaning out process and discovered that it saved cells from dying after exposure to the chemicals.
The team then replicated the experiment on human cells in a lab and found similar effects, suggesting diesel exhaust can contribute to brain processes that lead to Parkinson’s disease.
“Overall, this report shows a plausible mechanism of why air pollution may increase the risk of Parkinson’s disease,” Bronstein said in the news release.
Traffic pollution
Traffic-related pollution is on the rise in most countries, experts say, even more so in developing countries due to ongoing urbanization.
A report on traffic congestion revealed that Boston had the most traffic than any other city in America in 2019, with 149 hours lost per capita while sitting bumper-to-bumper.
Chicago, Pennsylvania, New York and Washington, D.C. followed, according to the report from INRIX, a private company that provides transportation analytics.
A typical vehicle releases “about 4.6 metric tons of carbon dioxide per year,” the Environmental Protection Agency said, which, according to the study, can increase risks to neurodegenerative diseases.
This story was originally published May 20, 2020 at 10:56 AM with the headline "Diesel exhaust can increase your risk of developing Parkinson’s disease, study says."
