According to new research, people who had surgery to cut the main nerve connecting the brain with the stomach, a longstanding treatment for ulcers, had a trend of a lower risk of developing Parkinson’s disease (PD). Published in the April 26 online edition of Neurology, this result adds weight to the hypothesis that PD may begin in the gut and travel to the brain.
Many scientists are investigating the idea that some of the earliest signs of PD are found in the nerve cells that line the digestive tract. For example, in recent years, scientists have found toxic clumps of alpha-synuclein protein,the hallmark of Parkinson’s,in the gut of people who later developed the disease. Additionally, early research suggests that the alpha-synuclein protein may spread through nerve cells from the intestines to the brain.
Bojing Liu, MSc, of the Karolinska Instituet in Stockholm, Sweden and study author said, “These results provide preliminary evidence that Parkinson’s disease may start in the gut.”
“Other evidence for this hypothesis is that people with Parkinson’s disease often have gastrointestinal problems such as constipation, that can start decades before they develop the disease. In addition, other studies have shown that people who will later develop Parkinson’s disease have a protein believed to play a key role in Parkinson’s disease in their gut.”
The theory is that these proteins can fold in the wrong way and spread that mistake from cell to cell.
Liu said, “Much more research is needed to test this theory and to help us understand the role this may play in the development of Parkinson’s.”
Additionally, since Parkinson’s is a syndrome, there may be multiple causes and pathways.
Even though the study was large, Liu said 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.
The study published in the journal Neurology.
Data from the national registers of Sweden were studied to compare 9,430 people who had a vagotomy between the years 1970 and 2010, with 377,200 individuals from the general population. Follow-up occurred over the 40-year period from the date of the vagotomy until Parkinson’s disease diagnosis, death, or emigration out of Sweden.
A plain vagotomy eliminates the parasympathetic supply from the stomach to the left side of the transverse colon.Other techniques focus on branches leading from the retroperitoneum to the stomach.
Highly selective vagotomy refers to denervation of only those branches supplying the lower esophagus and stomach (leaving the nerve of Latarjet in place to ensure the emptying function of the stomach remains intact). It is one of the treatments of peptic ulcer.
Vagotomy is an essential component of surgical management of peptic (duodenal and gastric) ulcer disease (PUD). Vagotomy was once commonly performed to treat and prevent PUD. However, with the availability of excellent acid secretion control with H2 receptor antagonists, such as cimetidine, ranitidine, and famotidine, and proton pump inhibitors (PPIs), such as pantoprazole, rabeprazole, omeprazole, and lansoprazole, the need for surgical management of peptic ulcer disease has greatly decreased.
All types of vagotomy can be performed at open surgery (laparotomy) or using minimally invasive surgery (laparoscopy).
One potential side effect of vagotomy is a vitamin B deficiency. As vagotomy decreases gastric secretion, intrinsic factor production can be impaired. Intrinsic factor is needed to absorb vitamin B efficiently from food, and injections or large oral doses of the vitamin may be required after such a procedure in certain populations.
Over the course of the study, 101 of the people (or 1.07 percent) who had a vagotomy developed Parkinson’s disease, compared with 4,829 individuals in the control group (or 1.28 percent). The difference between the vagotomized group and the general population was “not significant.”
But when 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.
A total of 19 people who had truncal vagotomy at least five years earlier developed the disease, or 0.78 percent, compared to 3,932 people who had no surgery and had been followed for at least five years, at 1.15 percent. By contrast, 60 people who had selective vagotomy five years earlier developed Parkinson’s disease, or 1.08 percent.
After adjusting for factors such as chronic obstructive pulmonary disease,diabetes, arthritis and other conditions, 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.
“Much more research is needed to test this theory and to help us understand the role this may play in the development of Parkinson’s,” Liu said. Additionally, since Parkinson’s is a syndrome, there may be multiple causes and pathways.
Even though the study was large, Liu said 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.
Commenting on the study for Medscape Medical News, James Beck, PhD, chief scientific officer, Parkinson’s Foundation, said, “This is a relatively modest effect, and an epidemiology study such as this one cannot show cause and effect, but these results are a further indication that there seems to be a connection between the gut and the brain in Parkinson’s disease.”