Serious Link Between Pesticide Chlorpyrifos and Parkinson's Disease: New Research Report
Scientists at UCLA have discovered that exposure to the widely used pesticide increases the risk of Parkinson's by 2.5 times and disrupts the brain's cleaning system.
A common pesticide widely used for decades in agriculture to eliminate insects and pests can significantly increase the risk of Parkinson's disease, a serious brain disorder. Researchers at the University of California, Los Angeles (UCLA Health) have discovered that this chemical inhibits the process of clearing toxic substances in brain neurons. This study was published in the prestigious scientific journal Molecular Neurodegeneration.
According to the research, people who have been exposed to a pesticide called 'chlorpyrifos' for a long time have more than 2.5 times the risk of developing Parkinson's disease compared to the general population. Scientists have also identified the biological pathway through which this pesticide damages the brain cells responsible for body control and movement. This discovery has raised hopes for developing new drugs and treatment methods to protect brain cells from destruction in the future.
જોખમ ગણા (Risk Ratio)
Study Structure and Statistical Evidence
To understand this link precisely, UCLA scientists conducted a large-scale study. They examined the health and residential data of 829 patients suffering from Parkinson's disease and 824 healthy individuals without the disease. All these participants were enrolled in the university's long-running 'Parkinson's Environment and Genes' study.
Researchers compared detailed pesticide spraying records from the state of California with the historical addresses of the participants' homes and workplaces. Using this method, they were able to accurately estimate the extent to which each individual was exposed to chlorpyrifos during their lifetime. The results clearly showed that continuous exposure to the pesticide increases the risk of Parkinson's by 2.5 times.
| Criteria / Detail | Patient group / Test model | Comparison / Result |
|---|---|---|
| Human study participants | 829 Parkinson's patients | 824 healthy individuals (control) |
| Laboratory mouse model | 11 weeks aerosol exposure | Degeneration of dopamine cells and inflammation |
| Zebrafish model study | Exploration of autophagy process | Protein accumulation due to blocked cellular cleaning |
To confirm these findings in the laboratory, researchers conducted experiments on mice. They exposed the mice to chlorpyrifos in the form of an aerosol (microscopic particles mixed in the air) for 11 weeks, which was similar to the natural condition of inhaling the pesticide in humans. As a result, the mice developed walking and movement difficulties, and the dopamine-producing neurons in their brains degenerated.
- 1. Pesticide exposureChlorpyrifos chemical enters the body and nervous system through air or residential area.
- 2. Blockage in autophagyThe natural recycling system (autophagy) that cleans waste proteins in neurons is disrupted.
- 3. Accumulation of toxic proteinsDue to stopped cleaning, alpha-synuclein protein accumulates in the form of toxic clumps (Lewy bodies).
- 4. Destruction of dopamine cellsDue to cellular stress and inflammation, dopamine-producing neurons die, leading to Parkinson's.
Destruction of the Brain's Cleaning System: Disturbance in Autophagy
In the experiments on mice, scientists observed inflammation in the brain and the accumulation of abnormal clumps of a protein called 'alpha-synuclein'. Under normal conditions, alpha-synuclein is useful in neurons, but when it accumulates in the form of clumps, it becomes extremely toxic to the cells. These clumps are known as 'Lewy bodies'.
To understand how the pesticide damages cells, the team then turned to a small fish model called 'zebrafish'. In neuroscience, this fish is used to study the processes of cell development and survival. These experiments made it clear that chlorpyrifos severely disrupts 'autophagy' (the natural recycling process that cleans up waste and damaged proteins inside cells).
Autophagy is extremely important for brain neurons because nerve cells must remain functional throughout the week or an entire lifetime. When the pesticide blocks this cleaning process, damaged proteins begin to accumulate inside the neurons and eventually lead to cell death. Surprisingly, when scientists in the laboratory reactivated the autophagy process or removed the synuclein protein, the brain cells were saved from destruction.
Symptoms and Physical Effects of Parkinson's Disease
Parkinson's is a serious disease of the central nervous system that gradually destroys the dopamine-producing cells (dopamine: a chemical that transmits signals in the brain and controls movements) located in an area of the brain called the 'substantia nigra'. As dopamine levels decrease, the brain is unable to maintain the balance of the body's limbs.
The four main physical symptoms of the disease include tremors or shaking in the limbs, slowness of movement or bradykinesia, muscle rigidity, and postural instability. In addition, mental symptoms such as insomnia, reduced sense of smell, depression, and anxiety are also observed in patients. This disease affects approximately 1 percent of people over the age of 60.
History and Global Status of Chlorpyrifos
Chlorpyrifos has been used for decades to prevent pests on cotton, corn, almonds, and various fruits and vegetables. Given its serious toxic effects, its household use was banned in the United States in 2001. Subsequently, in 2021, strict restrictions were imposed on its use in agriculture.
Despite this, chlorpyrifos is still being used on a large scale today on some crops in America and in many other countries around the world. Since years pass between the use of the pesticide and the appearance of disease symptoms, it is very important to understand its long-term exposure. This research can help in identifying, at an early stage, those people who may have been exposed to this chemical in the past.
According to Dr. Jeff Bronstein, professor of neurology at UCLA Health and senior author of the study, "This study establishes chlorpyrifos not just as a common pesticide, but as a specific environmental risk factor for Parkinson's disease. By demonstrating the biological mechanism in animal models, we have proven that this link is causal. The discovery that autophagy dysfunction is toxic to the nervous system leads us toward new therapeutic approaches to protect brain cells."
