Two Pathways to Parkinson’s Could Point to a Single Way to Prevent It : ScienceAlert

Different models of how Parkinson’s develop could represent a disease largely triggered by something in our environment, suggesting ways to prevent a significant number of cases.

For some time, researchers have wondered whether the progressive loss of neurons associated with Parkinson’s disease comes primarily from olfactory nerves in the brain or nerves in the gut.

The compelling model proposed by an international team of researchers suggests that the neurodegenerative disease could begin with the spread of toxic proteins from either source, triggered by damage caused by possible environmental factors in both regions.

Ultimately, substances inhaled through the nose (hitting the brain’s olfactory center) and ingested through the stomach could both be responsible for Parkinson’s disease, researchers say — and future studies should be able to clarify these links.

“In brain-first and body-first scenarios, pathology arises in body structures that are closely linked to the outside world,” says neurologist Ray Dorsey of the University of Rochester Medical Center.

“We propose here that Parkinson’s disease is a systemic disease and that its initial roots likely begin in the nose and gut and are linked to environmental factors increasingly recognized as major contributors, if not causes, of disease.”

The team points to dry cleaning and degreasing chemicals, air pollution, the use of herbicides, weedkillers and contaminated drinking water among environmental toxicants that can trigger brain dysfunction. .

We think this happens by the misfolding of the alpha-synuclein protein, which then accumulates in clumps called Lewy bodies. These clumps then eliminate many nerve cells in the brain, including those responsible for motor control.

Although this new study is only theoretical, it references previously confirmed links between Parkinson’s disease and many environmental risks. However, it will take some time to distinguish these links more precisely.

“These environmental toxicants are very widespread, and not everyone gets Parkinson’s disease,” Dorsey says.

“The timing, dose and duration of exposure as well as interactions with genetic and other environmental factors are likely critical in determining who ultimately develops Parkinson’s disease.”

The researchers admit that this new theory leaves some questions unanswered, including what role the skin and microbiome might play and how disease risk changes due to prolonged exposures over time.

In fact, exposures could often occur years or even decades before Parkinson’s symptoms appear – but approaching disease research using this new hypothetical model should help determine whether these links actually exist.

“This further reinforces the idea that Parkinson’s disease, the fastest growing brain disease in the world, may be fueled by toxic substances and is therefore largely preventable,” says Dorsey.

The research was published in the Parkinson’s Disease Journal.