Pesticide Exposure May Mean an Increased Risk of Parkinson’s Disease for Some
Posted on June 29, 2018
A new study from the University of Guelph in Ontario, Canada, has revealed how exposure to pesticides can mean an increased risk of developing Parkinson’s disease for some individuals.
Earlier research linked exposure to two commonly used pesticides, paraquat and maneb, to the degenerative disorder of the central nervous system.
Parkinson’s affects around 1 million people in the United States, with 60,000 new cases diagnosed each year, according to the Parkinson’s Foundation.
“Parkinson’s affects about 10 million people worldwide. Causes of the condition are thought to be both genetic and environmental, which makes the findings of this study critical,” said Dr. Joel Singer.
Singer is a New York physician who treats Parkinson’s disease patients using personal cell therapy.
The effects of Parkinson’s disease vary widely between individuals and include lack of muscle control, spasms, urinary incontinence, impaired speech, dementia and fatigue. One of the most notable and most recognizable symptoms are tremors that cause uncontrollable shaking, which makes day-to-day living very difficult.
“Tremors can make everything from writing a letter to making a phone call, driving and feeding yourself very difficult,” Singer said.
The Guelph researchers found that exposure to these pesticides causes a disruption in cells that is similar to the genetic mutations that cause Parkinson’s disease.
The combination of chemical exposure and a family history of Parkinson’s disease significantly increased the risk of developing the condition, researchers found.
Around 15 percent of people with Parkinson’s disease have a family history of the condition, according to the National Institutes of Health’s Genetics Home Reference. The NIH’s GHR aims to provide consumer-friendly information regarding how genetic variations affect human health.
Individuals with a predisposition to Parkinson’s disease and who have been exposed to the agrochemicals have a 250 percent greater risk of developing the condition than the rest of the population.
Paraquat and maneb are widely used on Canadian crops. Paraquat is used while plants are growing, while maneb is applied after the crops are harvested to prevent spoiling.
The researchers on the study took adult stem cells from individuals living with Parkinson’s disease who had a variation in the synuclein, a gene that is connected to Parkinson’s disease. They also used normal human embryonic stem cell that were modified using gene editing to have the variation.
Prior studies of the pesticides and Parkinson’s disease link were mainly based on animal studies and research among farmers and other individuals exposed to agrochemicals regularly and for prolonged periods. The Guelph study is one of the first to examine the impact of these pesticides on cell functions.
Using both the adult stem cells and the edited embryonic stem cells, the researchers developed dopamine-producing neurons and exposed them to the paraquat and maneb.
Dopamine-producing neurons act as neurotransmitters in controlling muscle and other body functions. These cells are the nerve cells directly impacted by Parkinson’s disease.
After the cells were exposed to the pesticides, the cells’ mitochondria, which produce energy for the cell, were blocked from moving into areas inside the cell, which meant a loss of energy for the neurons.
The researchers hope that the results of the study show cause for evaluating how the chemicals are used and as a warning for individuals working and living near agricultural sites.
Source: University of Guelph. “Study uncovers cause of pesticide exposure, Parkinson’s link: Low-level exposure to the pesticides disrupts cells in a way that mimics the effects of mutations known to cause Parkinson’s disease.” ScienceDaily. ScienceDaily, 23 May 2018.