Diesel Exhaust May Increase the Risk of Parkinson’s Disease

Medical professionals are already aware that inhaling air pollution can increase one’s risk of a number of conditions, including respiratory and heart diseases. They are now discovering that it can also heighten one’s chance of Parkinson’s. Using zebra fish, researchers at UCLA found that diesel exhaust is linked to neurodegeneration. Fortunately, they also found that a leukemia drug, Tasigna, may decrease the levels of neural toxicity caused by inhaling this exhaust.

About Parkinson’s Disease

Parkinson’s disease is a progressive disorder that affects the central nervous system (CNS). It is characterized by its effect on movement through five different stages. As the disease progresses, severity increases. Stage one is characterized by subtle tremors on one side of the body. In stage two symptoms are more noticeable, with tremors and rigidity on both sides of the body. Stage three brings loss of balance and slow movement, while stage four makes it impossible for one to live independently. Stage five is the most severe, as patients cannot stand or walk. Hallucinations and delusions are common symptoms of this stage.

Parkinson’s disease occurs due to the death of motor neurons, some of which produce dopamine. Dopamine is important in the transmittance of messages to the muscles from the brain, so the loss of dopamine results in the loss of motor functions. Abnormal brain activity occurs when these neurons are lost. Doctors do not know why these motor neurons die, but they do suspect a few factors that play a role, such as genetics, environmental factors like toxins, and Lewy bodies.

There are no FDA approved therapies for Parkinson’s, and treatment is symptomatic. Treatment options include dopamine substitutes, carbidopa-levodopa, MAO-B inhibitors, catechol-O-methyltransferase (COMT) inhibitors, anticholinergics, and amantadine.

UCLA’s Research

Zebra fish are an optimal choice for studying the brain, as they share similar neuronal networks to humans and can be used to study environmental toxins. With this information, researchers polluted the fish’s water with diesel exhaust. The results were immediate. In the same day, the way in which the fish swam changed, and neurons in the brain were dying.

Researchers concluded that autophagy was connected to these events. Autophagy is a cellular process that gets rid of accumulations of toxins. Essentially, there were small build-ups of toxins that fused with lysosomes before the diesel exhaust was added to the water, and those build-ups stopped merging with lysosomes after the toxins were added. Examining this phenomenon even further, researchers found that there was aggregation of the synuclein gamma 1 protein in the neurons. This protein shares a family to a protein that is known to aggregate in neurons in Parkinson’s patients.

After discovering this, researchers used Tasigna, a leukemia medication. This drug has been known to improve autophagy in zebra fish. They found that it was able to rescue the neurons from cell death.

This study tells us three things. One, that diesel exhaust contributes to features of Parkinson’s. Two, issues with autophagy are a primary driver of toxicity in the neurons in neurodegenerative diseases. And lastly, Tasigna and drugs like it may be viable options for treating Parkinson’s and conditions like it.

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