Does Parkinson’s disease begin in the gut? New research suggests it does – Los Angeles Times

They say that what happens in Vegas stays in Vegas. But this is definitely not true of the vagus nerve, which wanders from the stomach to the brain, passing through the heart, esophagus and lungs along the way.

A new study offers fresh support for an intriguing theory about the vagus nerves role in Parkinsons disease, a neurological disorder that causes tremors, gait difficulties and sometimes dementia in roughly 1 million Americans and as many as 10 million people worldwide.

This theory suggests the vagus nerve may be more than a highway for signals to travel to the brain from the many organs it touches. It may also be the conduit for transporting the protein alpha-synuclein from the stomach to the brain, where it forms telltale clumps in Parkinsons sufferers.

If true, this theory would pinpoint a possible origin of the degenerative brain disorder in the gut. It would also confirm the centrality of this mysterious protein, whose precise role in Parkinsons is not well understood.

And finally, it would suggest a possible way to block the progression of Parkinsons: a surgical procedure currently used to treat people with gastric ulcers that cuts the vagus nerve to sever the pathway from gut to brain.

This last point is where the new research begins.

The study authors, from Swedens Karolinska Institute, USC and elsewhere, combed through a comprehensive registry of Swedish medical records to compare rates of Parkinsons disease among people who got that surgical procedure, called vagotomy, and those who had not.

They wondered if, incidental to vagotomys role as a treatment for peptic ulcers, it might also drive down the risk of Parkinsons by blocking alpha-synucleins route to the brain.

What they found did not appear, at first blush, to be telling: Swedens 9,430 vagotomy patients were statistically no less likely to develop Parkinsons over time than were the 377,200 non-vagotomized Swedes that made up the comparison group.

But not all vagotomies are equal, and when the researchers looked at the subset of patients who got the most drastic version of the procedure, they saw a difference.

Among patients who got a truncal vagotomy which removes the vagus nerve from contact with the stomach, liver, gall bladder, pancreas, small intestine and proximal colon many years of follow-up showed that Parkinsons disease was 22% less common than it was among people in the comparison group.

While the theory that Parkinsons starts in the gut is controversial, there is some evidence for it in mice, in laboratory cells and in humans. Alpha-synuclein protein clumps have been detected in the guts of humans with very early Parkinsons. And in mice who had alpha-synuclein from the brains of human Parkinsons patients implanted in their intestinal wall, researchers later found movement of those proteins in the vagus nerve.

This latest study, published Wednesday in the journal Neurology, offers epidemiological evidence to support that theory.

If this is true, the study authors wrote, resection of the vagus nerve may stop or delay the spreading of the the proteins that gum up the works in the brains of Parkinsons patients.

melissa.healy@latimes.com

Twitter: @LATMelissaHealy

MORE IN SCIENCE:

Spacecraft Cassini's first pass between Saturn and its rings goes flawlessly

130,000-year-old mastodon bones could rewrite story of how humans first appeared in the Americas

Stubborn plastic may have finally met its match: the hungry wax worm

See the article here:
Does Parkinson's disease begin in the gut? New research suggests it does - Los Angeles Times