NWPF

News ArchivesRead News

How Pesticides Can Cause Parkinson's

Friday July 19, 2013

Foreign chemicals may prevent the brain from disposing of its own toxic waste
Melinda Wenner Moyer

Scientific American - Many studies over the past decade have pointed to pesticides as a potential cause of Parkinson's disease, a neurodegenerative condition that impairs motor function and afflicts a million Americans. Yet scientists have not had a good idea of how these chemicals harm the brain. A recent study suggests a possible answer: pesticides may inhibit a biochemical pathway that normally protects dopaminergic neurons, the brain cells selectively attacked by the disease. Preliminary research also indicates that this pathway plays a role in Parkinson's even when pesticides are not involved, providing an exciting new target for drug development.

Past studies have shown that a pesticide called benomyl, which lingers in the environment despite having been banned in the U.S. in 2001 because of health concerns, inhibits the chemical activity of aldehyde dehydrogenase (ALDH) in the liver. Researchers at the University of California, Los Angeles, U.C. Berkeley, the California Institute of Technology and the Greater Los Angeles Veterans Affairs Medical Center wondered whether the pesticide might also affect levels of ALDH in the brain. ALDH's job is to break down DOPAL, a naturally forming toxic chemical, rendering it harmless.

To find out, the researchers exposed different types of human brain cells—and, later, whole zebra fish—to benomyl. They found that it “killed almost half of the dopamine neurons while leaving all other neurons tested intact,” according to lead author and U.C.L.A. neurologist Jeff Bronstein. When they zeroed in on the affected cells, they confirmed that the benomyl was indeed inhibiting the activity of ALDH, which in turn spurred the toxic accumulation of DOPAL. Interestingly, when the scientists lowered DOPAL levels using a different technique, benomyl did not harm the dopamine neurons, a finding that suggests that the pesticide kills these neurons specifically because it allows DOPAL to build up.

Because other pesticides also inhibit ALDH activity, Bronstein speculates that this pathway could help explain the link between Parkinson's and pesticides in general. What is more, research has identified high DOPAL activity in the brain of Parkinson's patients who have not been highly exposed to pesticides, so it is possible that this biochemical cascade is involved in the disease process regardless of its cause. If that is true, then drugs that block or clear DOPAL from the brain could prove to be promising treatments for Parkinson's.

Recent News

Jul 14 - Cancer drug shows early promise for Parkinson's disease
Jul 13 - Opinion: Dividing the Caregiving Responsibilities Between Siblings
Jul 12 - Researchers make advance in possible treatments for Gaucher, Parkinson’s diseases
Jul 11 - Parkinson’s Head Trauma Link Looks Even Stronger
Jul 7 - Penn students’ start-up XEED puts wearables to work against Parkinson’s disease
Jul 5 - Last Patient Enrolled in Pivotal Phase 3 Parkinson’s Disease Trial, Cynapsus Therapeutics Says
Jun 29 - Exoskeleton Could Quell the Tremors of Parkinson's Disease Patients at Crucial Moments
Jun 28 - Parkinson's disease: New protein discovery could fuel new treatments
Jun 27 - Study finds direct evidence linking Parkinson’s to autoimmune disease; 2 genes that are key regulators of immune system discovered
Jun 27 - Blocking key enzyme halts parkinson's disease symptoms in mice
Jun 23 - Parkinson's Research Might Benefit from Novel Discovery of Zinc Transport Protein Structure
Jun 23 - Parkinson's disease breakthrough 'could lead to cure'
Jun 20 - More American men diagnosed with Parkinson's
Jun 15 - First monkey genetically engineered to have Parkinson’s created
Jun 14 - Fighting Parkinson's in the lab
Jun 9 - A New Gene Has Been Linked to Parkinson's Disease
Jun 6 - A neurologist weighs in on Muhammad Ali's battle with Parkinson's disease
Jun 5 - Michael J. Fox: How to honor Muhammad Ali
Jun 3 - Singing improves speech of people with Parkinson's, but more research needed
Jun 1 - San Diego Parkinson’s Research Sparks Ethical Discussion