The composition of our gut microbes may change through the development of many diseases.
Parkinson’s disease may be triggered by gut microbes, according to a California Institute of Technology (Caltech) study that points to probiotics as a potential therapy for the disease.
Findings from the team point to the gut as the origin of Parkinson’s disease, not only in the brain as previously thought.
Gastrointestinal problems such as constipation often precede the decline in motor skills seen in patients with Parkinson’s.
Beneficial bacteria is the gut are known to attack pathogens, manufacture vitamins and even act as anti-cancer agents. Recent research has strengthened the scientific understanding that the microbes that live in your gut may affect what goes on in your body.
Trillions of bacteria are hostile and can cause disease, while many others are friendly and have established a symbiotic, mutually beneficial relationship with us over the millennia.
These friendly bacteria have also been referred to as “probiotics” and are being used increasingly by mainstream clinicians for both preventive and therapeutic purposes.
The team used mice bred to produce high levels of alpha-synuclein. This protein is associated with brain damage in Parkinson’s sufferers.
However, only mice with bacteria in their gut developed Parkinson’s symptoms – an observation not seen in sterile mice.
When bacteria from individuals with Parkinson’s were transplanted into these mice, more symptoms were observed when compared to bacteria taken from healthy people.
The genomes of the bacteria and viruses of the human gut alone are thought to encode 3.3 million genes.
“The genetic richness and complexity of the bugs we carry is much richer than our own,” says Jayne Danska, an immunologist at the Hospital for Sick Children Research Institute in Ontario, Canada.
“They serve as a buffer and interpreter of our environment. We are chimeric organisms.”
Bacterial species from Parkinson’s donors included Proteus, Bilophila, and Roseburia, with a loss of members of families Lachnospiraceae, Rikenellaceae, and Peptostreptococcaceae, as well as Butyricicoccus.
According to the European Parkinson’s Disease Association, 1.2 million people in Europe have Parkinson’s.
The disease sees the brain become progressively damaged over many years, with the main symptoms being involuntary shaking, slow movement and stiff and inflexible muscles.
“We have discovered for the first time a biological link between the gut microbiome and Parkinson’s disease,” said senior study author and professor of Microbiology at Caltech, Dr Sarkis Mazmanian.
The gut: target for therapy?
Lactobacillus casei has shown efficacy in addressing constipation, a secondary symptom of Parkinson’s disease.
The use of pre- and probiotics in the treatment of Parkinson’s has been touted as an effective therapy for managing the condition’s symptoms.
One study, which used milk fermented with the probiotic strain Lactobacillus casei to treat constipation as a secondary symptom of the condition, resulted in improvements to stool consistency and bowel habits in Parkinson’s patients.
These latest study findings appear to deal with the molecular hallmarks of the condition. However, the authors acknowledged there was some way to go before antibiotics or faecal microbe transplants become viable therapies.
“Long-term, high-strength antibiotic use, like we utilised in this study, comes with significant risk to humans, such as defects in immune and metabolic function,” said co-author Dr Timothy Sampson, postdoctoral scholar at Caltech.
“Gut bacteria provide immense physiological benefit, and we do not yet have the data to know which particular species are problematic or beneficial in Parkinson’s disease.”
Dr Arthur Roach, director of research and development at charity Parkinson’s UK added further studies were required in other model systems and in humans to confirm the connection.
By Mae Chan