According to an article in Diagnostic Imaging, MRIs and PET scans show that Parkinson’s disease may start as either body-first or brain-first, in effect behaving like two different diseases.
Clinicians have suspected for years that Parkinson’s may be more than just one disease. Professor Per Borghammer, at Denmark’s Aarhus University, acknowledged that clinicians have wondered why there should be such a difference in symptoms among patients. Now those questions have been answered.
In the past, Parkinson’s was analyzed according to its typical movement disorders. The disease begins when neurons (nerve cells) that are in a region of the brain controlling movement become damaged or die. This is attributed to the accumulation of a protein called alpha-synuclein that produces dopamine. A decrease in dopamine results in slow movements or stiffness.
On another front, researchers are exploring the interaction between dopamine and alpha-synuclein. They are trying to uncover what is causing damage to neurons and their early death in Parkinson’s disease.
The Aarhus University team recently published their paper in the neurology journal Brain.
Paving the Way For Personalized Medicine
Advanced imaging using PET and MRI scans confirmed that Parkinson’s is two very distinct conditions. One type starts in the intestines and travels to the brain. The other type begins in the brain and moves to the intestines and various other organs.
It is also possible that the well-known risk factor of an isolated REM sleep disorder may be associated with the body-first disease.
In addition to the advanced imaging, as proof of their findings, Professor Borghammer and Medical Doctor Jacob Horsager, his colleague at Aarhus University, enrolled thirty-seven Parkinson’s patients in a PET study.
Brain First
Study results showed that one group of patients had damage to the dopamine system in the brain before the intestines and heart showed any damage.
Now that the scientists are aware of “brain-first” Parkinson’s, the challenge is to detect the disorder early. This is difficult because the disease is mostly symptom-free until the appearance of movement issues. By then, over half the dopamine system has been lost.
Body First
The other patient cohort showed that the nervous systems in the heart and intestines were damaged before damage to the dopamine system in the brain was apparent.
Professor Borghammer suggested that in cases of body first it would be helpful to research intestinal bacteria. He said that it has been demonstrated that the microbiome in the intestines of people with Parkinson’s differs from healthy people. He suggested the possibility of treating these patients with feces transplantation among other procedures that would impact the microbiome.
Despite the challenges that lie ahead, the team is encouraged and believe that their findings will lead to improved targeted therapy programs.
