At first, he noticed a twitch in one of his fingers. “It’s nothing”, he thought. But as time went on, the movements did not stop. So Michael J Fox, who played Marty McFly in the popular Back to the Future film saga, decided to go to the doctor, who, unfortunately, diagnosed him with Parkinson’s disease in 1991. At that time, the American actor was only thirty years old. Like him, there are 6.3 million people suffering from this condition worldwide, according to the European Parkinson’s Disease Association. Normally, the age of onset is over sixty, but it is estimated that 10% of patients are diagnosed before the age of fifty – and that’s what happened to the actor.

Parkinson’s disease (PD) is a progressive neurodegenerative condition that results in the gradual loss of cells responsible for the production of dopamine, a neurochemical transmitter essential for the coordination of movement. That means that this neurological disease eventually renders some patients unable to walk, to talk or even to take care of themselves.  As things are now, researchers do not know either the exact cause or a cure for the condition. However, a new study conducted at the University of Helsinki and the Helsinki University Central Hospital seems to shed some light on the subject.

Finnish experts led by neurologist Filip Scheperjans of the Departament of Neurology of the Helkinski University Hospital, showed for the first time that there are differences between the gut microbiota of PD patients and that of healthy subjects and that these differences may be related to both the symptom’s severity and the clinical phenotype of the disease. This new study fits in a chain of previous research that proposed PD to be of gastrointestinal origin.

Based on a study conducted with 72 Parkinson’s patients and 72 control subjects, Scheperjans and his team saw that patients with Parkinson’s had much less bacteria in their guts from the Prevotellaceae family than their healthy counterparts did. Researchers also detected a direct correlation between the amount of microbes from the Enterobacteriaceae genus in the intestines of patients and the degree of severity of balance and walking problems. The more Enterobacteriaceae they had, the more severe their symptoms were. In a short article published in, Doctor Scheperjans stated that, “the abundance of Enterobacteriaceae was related to the severity of postural instability and gait difficulty. So there was a connection between the gut microbiota and the motor symptoms of our patients. Our study is the first to demonstrate alterations of gut microbiota composition in neurodegenerative disease”.

Researchers are now re-examining the same patients, in order to determine whether the differences are permanent, and whether the intestinal bacteria are associated with the progression of the disease and, therefore, its prognosis. “We will have to see if the changes in the bacterial ecosystem existed before the onset of motor symptoms. We will, of course, also try to establish the basis of this connection between intestinal microbiota and Parkinson’s disease, what kind of mechanism binds them”, Scheperjans considers.

This new study, founded by the Michael J Fox Foundation for Parkinson’s Research and the Finnish Parkinson Foundation, which has been published in  Movement Disorders, the clinical journal of the International Parkinson and Movement Disorder Society, is in addition to other recent papers that have been able to relate gut microbes to a variety of health conditions and diseases such as obesity, depression, schizophrenia and lupus.

Scheperjans and his team hope that their results could be used to create a diagnostic test for Parkinson’s disease, and may pave the road for the development of better treatment strategies and, possibly, even prevention strategies that  focus on microbiota.