Scientists have gut feeling about Parkinson’s link
Abnormal protein stored in appendix may play a role
WASHINGTON — Scientists have found a new clue that Parkinson’s disease may get its start not in the brain but in the gut — maybe in the appendix.
People who had their appendix removed early in life had a lower risk of getting the tremor-inducing brain disease decades later, researchers reported Wednesday.
Why? A peek at surgically removed appendix tissue shows this tiny organ, often considered useless, seems to be a storage depot for an abnormal protein — one that, if it somehow makes its way into the brain, becomes a hallmark of Parkinson’s.
The big surprise, according to studies published Wednesday in the journal Science Translational Medicine: Lots of people may harbour clumps of that worrisome protein in their appendix — young and old, people with healthy brains and those with Parkinson’s.
But don’t look for a surgeon just yet.
“We’re not saying to go out and get an appendectomy,” stressed Viviane Labrie of Michigan’s Van Andel Research Institute, a neuroscientist and geneticist who led the research team.
After all, there are plenty of people who have no appendix yet still develop Parkinson’s. And plenty of others harbour the culprit protein but never get sick, according to her research. THE GUT CONNECTION
Doctors and patients have long known there’s some connection between the gastrointestinal tract and Parkinson’s. Constipation and other GI troubles are very common years before patients experience tremors and movement difficulty that lead to a Parkinson’s diagnosis.
This week’s new research promises to re-energize work to find out why, and learn who’s really at risk.
Parkinson’s Foundation chief scientific officer James Beck, who wasn’t involved in the new studies, noted that despite its reputation, the appendix appears to play a role in immunity that may influence gut inflammation. The type of bacteria that live in the gut also may affect Parkinson’s.
But if it really is common to harbour that Parkinson’s-linked protein, “what we don’t know is what starts it, what gets this whole ball rolling,” Beck said.
For years, scientists have hypothesized about what might cause the gut-Parkinson’s connection.
One main theory was that bad “alpha-synuclein” protein can travel from nerve fibres in the gastro-intestinal tract up the vagus nerve, which connects the body’s major organs to the brain. Abnormal alpha-synuclein is toxic to brain cells involved with movement.
There have been prior clues. People who decades ago had the vagus nerve cut as part of a now-abandoned therapy had a reduced risk of Parkinson’s.
Some smaller studies have suggested appendectomies, too, might be protective — but the results were conflicting.