Parkinson’s disease affects millions of people all over the world, with over 80,000 in Australia where it is the second most common neurological disease following dementia. There are 32 new cases diagnosed every day in Australia and 20% of them are in people who are under the age of 50, a fact that shakes up the belief that Parkinson’s is a disease that only affects older people.
Parkinson’s is a neurological condition affecting dopamine production in brain cells. It is the decrease in dopamine that leads to the loss of control of body movement, motor skills and coordination in Parkinson’s patients. This is a progressive and degenerative disease which is usually diagnosed only after there is a loss of 80% of dopamine producing cells and symptoms are already present.
Scientists have been studying Parkinson’s for years, focusing on the brain as their main target until recently, new studies have sent them off in a different direction: the microbiome of the gut and its bacterial composition.
Initially, several institutions including the California Institute of Technology, Rush University Medical Center in Chicago and Chalmers University of Technology in Sweden worked together to carry out research into whether or not the bacteria in a person’s gut resulted in Parkinson’s disease. The Knut and Alice Wallenberg Foundation funded the research project together with the Swedish Research Council.
In this study using mice, researchers introduced gut bacteria from people with Parkinson’s into one group, gut bacteria from healthy people into a second group and no bacteria into a third group. It is through this study that they discovered that bacteria in the gut was essential in triggering symptoms similar to Parkinson’s. Their results showed that the group of mice with bacteria from Parkinson’s patients had the greatest decline in motor function and the least affected were the mice who were not given any bacteria.
A second study involving 197 patients with Parkinson’s and 130 controls conducted at the University of Alabama at Birmingham, shows that Parkinson’s disease, as well as medications used to treat it, have effects on the bacterial composition that constitutes the gut microbiome. According to Haydeh Payami, Ph.D., professor in the Department of Neurology, in the UAB School of Medicine, results of this study show that individuals with Parkinson’s have “major disruption of the normal microbiome — the organisms in the gut”.
At the end of the studies what researchers discovered, in simple terms, is that chemicals produced by certain gut bacteria enhance the brain’s inflammatory response and that this, in turn, causes a decrease in motor function.
Unfortunately, the studies do not actually prove that Parkinson’s is a disorder of the gut, nor does it suggest that antibiotics or probiotics would treat or prevent the disease. What it does show is that this gut bacteria could be the cause of a build up of alpha synuclein proteins which are found in patients with Parkinson’s.
The question that researchers have yet to answer is what comes first. Does Parkinson’s disease itself cause the changes found in the gut microbiome? Or, are the observed changes a precursor to the disease? But, what this research does prove is that the initial symptoms of Parkinson’s appear at approximately the same time as gastrointestinal symptoms such as inflammation or constipation.
These interesting studies may not answer every question about Parkinson’s disease yet, but they will most definitely trigger more studies that can focus on an even narrower plane. New studies may lead to identifying specific bacteria that are harmful or helpful, how they connect to the disease and what sorts of treatment would be the most effective in protection against Parkinson’s.