Your brain and pesticides: How exposure could lead to Parkinson's disease
New research uncovers an even stronger link between the development of Parkinson’s disease and the environment from a fungicide that was widely used up until 10 years ago. Exposure to paraquat, maneb and ziram are known to be linked to the disease. UCLA researchers have discovered another contributor to the disease that comes from a pesticide that is now banned, but the effects still linger.
The newest pesticide that could influence the chances of the disease is a fungicide called benomyl that was marketed as Benlate and manufactured by Dupont. The pesticide has been banned by the EPA since 2001. The effects still linger 10 years later, according to background information from UCLA researchers who conducted the new study.
But the risk isn't just for farmers. Even people who live nearby and inhale toxic chemicals seem to be at higher risk for the debilitating neurological disease that affects millions worldwide.
Paraquat and rotenone have been shown in past studies to more than double the chances of Parkinson's.
The researchers believe the pesticide Benlate sets off a series of events that eventually could lead to Parkinson’s disease.
The chemical blocks action of an enzyme that’s necessary to prevent a natural toxin from building up in the brain that is a metabolite of dopamine – a hormone associated with a variety of functions in the brain. The toxin is known as DOPAL.
A study published in the journal PloS ONE, February 2011 showed DOPAL kills brain nerve cells through a series of events; found in rat studies.
Jeff Bronstein, senior author of the new study and a professor of neurology at UCLA explains it’s the same cascade of events that can occur in people who develop Parkinson’s but were never exposed to pesticides.
The scientists note only a small number of Parkinson’s patients have a genetic tendency toward the disease, which has led researchers to look for environmental causes.
Arthur G. Fitzmaurice, a postdoctoral scholar in Bronstein's laboratory said: “Understanding the relevant mechanisms — particularly what causes the selective loss of dopaminergic neurons — may provide important clues to explain how the disease develops.” He adds environmental factors “certainly play a role in this disorder”.
The researchers tested the effects of benomyl to find it destroyed neurons in cell cultures and in zebrafish models of the disease.
Symptoms of Parkinson’s disease include tremors and difficulty with balance, which can lead to falls and complications for patients suffering from the disease. One of the first symptoms is tremors. The disease is progressive. Symptoms vary from person to person. For some, the disease can progress rapidly and for others more slowly.
Prescription medications control symptoms and have to be taken throughout the day. The most effective medication is levodopa, but the drug is sometimes intolerable from side effects. Dopamine agonists might be used in combination with levodopa. The drug can be injected at home and relieves Parkinson’s symptoms quickly but the effect only last 30 to 60 minutes. The drug can be useful when other medications wear off making it impossible for patients with the disease to move.
Deep brain stimulation (DBS) is a surgical approach that has been used to help patients with the disease. The benefit might last up to 5 years and for some, the improvement in symptoms is dramatic. Not everyone is a candidate for DBS.
DBS involves inserting a device under the collarbone, similar to a pacemaker. Electrodes stimulate the part of the brain involved in motor function that is controlled by the patient. Another area being explored to treat the disease is gene therapy.
Until now a protein called α-synuclein that clumps in the brain to destroy neurons was cited as the culprit for Parkinson’s disease. Understanding how exposure to benomyl desroys cells in the brain to lead to Parkinson’s disease can open the door for new treatments for the disease. It’s also important to understand the new research showed if you live near an area where pesticides are or have been used you might also be at risk for the disease.
Proceedings of the National Academy of Sciences
“Aldehyde dehydrogenase inhibition as a pathogenic mechanism in Parkinson disease”
Arthur G. Fitzmaurice, et al.
December 24, 2012
Parkinson’s Disease Foundation
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