Investigating environmental factors and their effects on Parkinson’s disease

Yesterday on World Parkinson’s Day in the Journal of Parkinson’s Disease, researchers revealed the potential environmental origins of Parkinson’s disease

This study, led by experts including Dr. Per Borghammer from Aarhus University Hospital in Denmark and Dr. Ray Dorsey from the University of Rochester Medical Center, proposes a hypothesis that Parkinson’s disease may have its origins in environmental toxins that are either inhaled or ingested.

Exposure to toxins leads to Parkinson’s

The debate surrounding the source of Parkinson’s disease has long been divided between whether it originates in the brain or the body’s intestinal tract. Dr. Borghammer’s team argues that exposure to certain environmental toxicants can trigger either a “brain-first” or “body-first” progression of the disease.

Inhalation of pesticides, dry cleaning chemicals, and air pollution may lead to a brain-centric model of Parkinson’s, whereas ingesting tainted food or contaminated drinking water could predispose individuals to a body-centric model.

“This further reinforces the idea that Parkinson’s, the world’s fastest growing brain disease, may be fueled by toxicants and is therefore largely preventable.” says Dr. Dorsey, emphasising the importance of understanding and addressing environmental factors.

Toxic alpha-synuclein

The study points to specific environmental toxins such as trichloroethylene (TCE) and perchloroethylene (PCE), commonly found in dry cleaning and degreasing chemicals, as well as paraquat, a widely used herbicide in the United States.

These chemicals, along with air pollution, have been implicated in the formation of toxic alpha-synuclein, a misfolded protein associated with Parkinson’s disease.

The research suggests that when inhaled, these toxins can enter the brain through the nerve responsible for smell, initiating alpha-synuclein pathology in brain regions controlling motor function. When ingested, these toxins may first affect the gut’s nervous system, leading to a body-centric progression of the disease that mirrors Lewy body dementia.

Environmental toxins linked to other brain disorders

Dr. Dorsey emphasises that not everyone exposed to these toxicants develops Parkinson’s disease, highlighting the importance of considering factors like timing, dose, duration of exposure, and genetic predispositions.

The authors hope that these new models will enable researchers to connect specific environmental exposures to distinct forms of Parkinson’s disease, paving the way for preventive measures.

They believe that raising public awareness about the health risks set by environmental chemicals is crucial in combating this and other brain disorders.

Beyond Parkinson’s disease, this research may also contribute to our understanding of how environmental toxicants contribute to other brain disorders such as autism, ALS, and Alzheimer’s disease.

To further explore these connections, Dr. Dorsey and colleagues are organising a symposium on the Brain and the Environment in Washington, DC, aimed at investigating the role of toxicants in various brain diseases.