Parkinson’s disease may start in the gut and spread to the brain via the vagus nerve, according to a new study published in Neurology. The vagus nerve extends from the brainstem to the abdomen and controls unconscious body processes like heart rate and food digestion.
The preliminary study examined people who had resection surgery, removing the main trunk or branches of the vagus nerve. The surgery, called vagotomy, is used for people with ulcers. Researchers used national registers to compare people who had a vagotomy over a 40-year period to people from the general population.
When the researchers analyzed the results for the two different types of vagotomy surgery, they found that people who had a truncal vagotomy at least five years earlier were less likely to develop Parkinson's disease than those who had not had the surgery and had been followed for at least five years. In a truncal vagotomy, the nerve trunk is fully resected. In a selective vagotomy, only some branches of the nerve are resected.
After adjusting for factors such as chronic obstructive pulmonary disease, diabetes, arthritis and other conditions, the researchers found that people who had a truncal vagotomy at least five years before were 40 percent less likely to develop Parkinson's disease than those who had not had the surgery and had been followed for at least five years.
The researchers say that their results could add to other research that has indicated that Parkinson’s disease may start in the gut. For example, previous studies have shown that a protein linked to Parkinson’s disease has been found in the gut of people who later go on to develop the disease. The theory is that these proteins can fold in the wrong way and spread that mistake from cell to cell.
Even though the study was large, the researchers say that one limitation was small numbers in certain subgroups. Also, the researchers could not control for all potential factors that could affect the risk of Parkinson's disease, such as smoking, coffee drinking or genetics.
Paper: “Vagotomy and Parkinson disease: A Swedish register–based matched-cohort study”
Reprinted from materials provided by the American Academy of Neurology (AAN).