Probiotics May Reduce Some Signs of Gut Inflammation
Probiotic supplements could prove a useful add-on therapy for people with Parkinson’s disease, a recent study suggests.
The study, “Influence of probiotic bacteria on gut microbiota composition and gut wall function in an in-vitro model in patients with Parkinson’s disease,” was published in the International Journal of Pharmaceutics: X.
Although better known for its movement symptoms, Parkinson’s also affects the gut. Symptoms such as constipation and gastroparesis, which involves heartburn, nausea, vomiting, and feeling full quickly when eating, can precede motor symptoms by years, or even decades, in some cases.
Changes in gut microbe population — the gut microbiome — accompany these symptoms, affecting a person’s overall health, as well as the ability to efficiently absorb and metabolize medications.
Furthermore, gut microbe changes associated with Parkinson’s might reflect the processes that worsen other symptoms of the disorder: studies have suggested that gut inflammation can trigger the misfolding and clumping of the protein alpha-synuclein in the walls of the colon and in local immune cells. Aggregation of alpha-synuclein also causes the loss of brain cells that produce the chemical messenger dopamine, which leads to the hallmark symptoms of Parkinson’s.
These alpha-synuclein deposits then can travel from the gut to the brain via the vagus nerve — one of the longest nerves in the body and part of the enteric nervous system (ENS) that governs the function of the digestive tract.
Some past studies have shown that a probiotics solution of four strains of bacteria called Symprove has lowered the severity of several gut-related conditions, such as irritable bowel syndrome, and significantly reduced constipation and diarrhea in diverticular disease.
An international team of scientists from Belgium and the U.K. conducted a preclinical study to determine whether Symprove could alter the gut microbiome of Parkinson’s patients and whether probiotics could improve other indicators of gut health among these patients.
Because of the complications involved in conducting experiments directly inside people’s guts, the researchers created models of individuals’ gut microbiomes from stool samples taken from three people with Parkinson’s and three healthy controls.
Each sample was separated so that part of it was fermented in the presence of Symprove for 48 hours, and another part wasn’t.
After this incubation, the investigators compared changes in: bacterial composition and metabolic activity; the production of inflammatory molecules; how well cells responded to a simulated wound; and the strength of epithelial tight-junctions, connecting proteins that maintain the integrity of the intestinal barrier. These junctions appear to weaken in Parkinson’s, causing the intestines to grow leaky.
Overall, Symprove significantly changed the bacterial composition of the stool samples, and was associated with improvements in the other measured indicators of gut health.
Symprove treatment mainly increased the amounts of bacteria of the Actinobacteria and Firmicutes phyla, while decreasing those of the Bacteroidetes phylum.
While the researchers caution that findings regarding bacterial gut compositions are difficult to interpret, owing to a wide variety of variations across individuals, “It is clear from this study,” they wrote, “that even a single dose of probiotic was able to effect a change in microbial diversity over 48 [hours], meaning that if development and/or progression of [Parkinson’s] is influenced by gut microbiota dysbiosis then probiotic supplementation of the diet might be beneficial.”
Symprove also led to greater lactate, butyrate, and short-chain fatty acid (SCFA) production, higher levels of the anti-inflammatory molecules IL-6 and IL-10, and lower levels of the pro-inflammatory molecules MCP-1 and IL-8. Both lactate and SCFA are considered important in maintaining good health.
To test wound healing, the researchers grew a layer of cells in a lab dish to form a thin cellular layer. The scientists then scratched the layer (to create a wound) and added colonic samples from each donor on top of this layer, measuring the time it took for cells to grow back over it. Samples that had been grown with Symprove performed significantly better than those grown without, which the investigators attribute to having more butyrate available.
“Butyrate is the key factor that encourages wound closure and the positive results from dosing with probiotic arise from increased SCFA concentrations,” they wrote.
The results led the team to conclude that probiotics show potential as an add-on therapy to standard Parkinson’s treatments, although they warn that the small number of donors used in this study mean that results should be interpreted cautiously and replicated in future studies.
“Combined with human and animal data,” they wrote, “[the results] provide a compelling indication that probiotics may be a potential and cost-effective intervention in managing patients with Parkinson’s Disease.”
Symprove Ltd. funded the studies.