A new study published in the journal Annals of Neurology suggests that the vagus nerve — which connects the brain with he abdominal tract — may transport Parkinson’s disease from the stomach up to the brain. If the nerve is severed early, the occurrence of Parkinson’s can be halved, the research shows.
According to Elisabeth Svensson, a post-doc from the Department of Clinical Medicine at Aarhus University in Denmark and the lead scientist in the study, while no one is sure how Parkinson’s starts in the stomach, this study is the first direct evidence that the vagus nerve is involved in the development of the disease in humans.
“It may bring us one step closer to understanding how Parkinson’s develops,” says Svensson.
Last year a group of scientists led by Per Borghammer, an assistant professor at the Department of Clinical Medicine at Aarhus University in Denmark, and a co-author of the study, used a new PET scanning technique to show that Parkinson’s patients have fewer nerve connections in the stomach than healthy people. This indicates that Parkinson’s disease doesn’t just kill brain cells but also the nerve connections between the brain and the gut.
The study looked at more than 10,000 patients who had their vagus nerves severed in the 1970s and 1980s as part of a cure for stomach ulcers.
Approximately half the patients had the nerve severed completely, in a process called a vagotomy, while it was only partly severed in the other half of the patients.
The scientists investigated how many of these patients developed Parkinson’s and compared this with the occurrence of Parkinson’s in a control group of more than 100,000 people who had an intact vagus nerve.
They saw that patients with a completely severed vagus nerve experienced 50 percent fewer occurrences of Parkinson’s disease than the control group.
The study may settle an on-going dispute among scientists studying Parkinson’s disease, according to Borghammer.
“We hope that this suppresses doubts over whether or not Parkinson’s can start in the stomach, and that more money can be focused into funding research to look at why the disorder starts here,” he says.