Parkinson's May Spread From Gut to Brain via Vagus Nerve
Written by Editor   
Wednesday, August 12, 2015 12:00 AM

It seems that there is an increasing amount of evidence linking the brain and immune system with the function of the gut.  This study indicates that Parkinson’s Disease is less common in those who have had their vagus nerve severed than in those who have not indicating "a primary pathological process being initiated in the gastrointestinal mucosa, which then uses the vagus as a major entry point into the brain."

A large Danish epidemiologic study supports the theory that Parkinson's disease (PD) may begin in the gastrointestinal tract and spread through the vagus nerve to the brain. Researchers found that patients who have had the entire vagus nerve severed were less apt to develop PD.

"Their risk was halved after 20 years," Elisabeth Svensson, PhD, from the Department of Clinical Epidemiology, Aarhus University in Denmark, said in a statement.

"However, patients who had only had a small part of the vagus nerve severed were not protected. This also fits the hypothesis that the disease process is strongly dependent on a fully or partially intact vagus nerve to be able to reach and affect the brain," Dr Svensson noted.

In the past, vagotomy was commonly performed for peptic ulcer, the researchers note in their paper. The two most common procedures were full truncal vagotomy, in which both vagal trunks were severed, and superselective vagotomy, in which only the nerves supplying the fundus and body of the stomach were resected.

The researchers investigated the risk for PD in 5339 patients who had truncal and 5870 who had superselective vagotomy, in relation to 66,711 and 60,500 matched population controls, respectively.

A direct comparison of the two vagotomy groups showed that patients who had truncal vagotomy had a lower risk for PD than did those having the superselective procedure, after adjustment for age and sex. 

The risk for PD was also lower after truncal vagotomy when compared with the general population. The risk for PD in patients who had superselective vagotomy was similar to that in population controls overall and after 20 years.

These findings, say the researchers, "suggest that having an intact vagus nerve increases the risk of developing PD. The finding is in accord with a primary pathological process being initiated in the gastrointestinal mucosa, which then uses the vagus as a major entry point into the brain."


Source:  http://www.medscape.com/viewarticle/849140