Parkinson’s disease could start in the gut, as current research suggests. Typical Parkinson’s deposits can be detected not only in the brain, but also in the digestive system.

Parkinson’s disease is, like Alzheimer’s, a neurodegenerative disorder. It affects more than 4 million people around the world and usually develops after the age of 60.

In this disease, progressive destruction of nerve cells in the brain occurs. Typical symptoms include muscle tremors, muscle stiffness, slow movements, and unstable posture. For now, it is incurable and no specific causes are known.

GUT HEALTH SHOULD BE INCLUDED IN DIAGNOSIS AND THERAPY

In a study conducted at the Helsinki University Clinic (Finland) and published in the Journal of Parkinson Disease, the respective researchers examined the extent to which the intestine could be involved in the development of Parkinson’s disease. They concluded that if the intestines were taken into account in Parkinson’s diagnosis and therapy, the disease could be recognized more quickly and its progression slowed.

The study’s lead author, Dr Filip Scheperjans, states that some people suffer from gastrointestinal upset for years before experiencing typical Parkinson’s symptoms, such as hand tremors.

However, if the disease is diagnosed when these tremors appear, many neurons will have died, making therapy much more difficult. For this reason, one of the goals of Parkinson’s research is to discover new ways to detect the disease as early as possible, and the gut is clearly the center of attention.

DO PATHOLOGICAL DEPOSITS MIGRATE FROM THE INTESTINE TO THE BRAIN?

More and more studies suggest that Parkinson’s actually begins in the digestive system, at least in those affected who had digestive disorders years before being diagnosed.

In March 2017, researchers stated in a study that typical Parkinson’s deposits in the brain, the so-called alpha-synuclein protein, which causes nerve cells to die, can migrate from the brain to the stomach via the vagus nerve.

However, some scientists also suspect that the deposits take the opposite route, namely that alpha-synuclein could possibly enter the digestive system with food and travel from there to the brain.

There is talk of a pathologically leaky intestinal mucosa (the leaky gut syndrome), which together with dysbiosis (alteration of the intestinal flora) excessively stimulates the immune system and could lead to chronic inflammation and overactivation of nerve cells, with the subsequent alpha-synuclein formation.

One of the latest and important pieces of research supporting the gut-brain hypothesis for Parkinson’s has been published in the journal Neuron and has been conducted by scientists at Johns Hopkins University.

LEAKY GUT, FLORA DISORDERS, AND INFLAMMATION

As Dr Scheperjans points out, since alpha-synuclein deposits can also be found in the nervous system of the digestive system, concrete research must now be conducted to determine whether these deposits are actually identical to those in the brain.

Excessive permeability of the intestinal mucosa (leaky gut syndrome) appears to trigger alpha-synuclein deposits in the intestine. Therefore, it must now be verified whether Parkinson’s patients actually have a leaky gut syndrome.

Until now, the so-called immunohistochemistry has been used as a method to locate alpha-synuclein deposits, although with inconsistent results, so it is necessary to develop new methods to achieve more precise results.

Large clinical studies with Parkinson’s patients are required to fully investigate the mechanisms that could be behind the influence of the gut in the development of Parkinson’s disease. The composition of the intestinal flora of each patient should be examined before and after a diagnosis of Parkinson’s.

THE FUTURE THERAPY OF PARKINSON’S: DIET, PROBIOTICS AND PREBIOTICS

In any case, Finnish scientists working with Scheperjans are confident that the intestinal flora will play an important role in the development of new therapies for Parkinson’s for decades to come. These forms of therapy will include dietary changes, the use of probiotics and prebiotics, and stool transplants.

“In recent years we have discovered the importance of the connection between the gut and the brain in relation to Parkinson’s,” says Scheperjans. 

And Dr Patrik Brundin, editor-in-chief of the Journal of Parkinson’s Disease comments that “the gut is now the focus of Parkinson’s research. We are confident that there will be tremendous progress in the next 20 years. Because changes in the Gut health can help diagnose Parkinson’s disease earlier, while therapies that affect those changes can delay the disease. This includes measures as simple as eliminating chronic constipation and improving overall bowel function.”

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