Matthew Sacheli, PhD, on Dopamine Release in Parkinson Disease
Parkinson disease affects more than 10 million people worldwide. The Parkinson’s Foundation estimates that nearly 1 million people in the United States will be living with Parkinson disease by 2020, which highlights the need for research on new treatments and, ultimately, a cure.
Matthew Sacheli, PhD Candidate, is a researcher at Pacific Parkinson’s Research Center and the Djavad Mowafaghian Centre for Brain Health at the University of British Columbia in Vancouver, British Columbia, Canada.
His latest research1 on Parkinson disease examined the differences in dopamine release, reward signaling, and clinical features between habitual exercisers and sedentary individuals living with Parkinson disease. Matthew answered a few of our questions about his research.
Neurology Consultant: Can you tell us about the findings and how they may affect clinical practice?
Matthew Sacheli: This study served as an initial foray into investigating whether there are differences in dopamine release and function, in people with Parkinson’s disease who exercise regularly compared with those who do not. In the group that exercise regularly, there was greater dopamine release in the caudate and more activation in the ventral striatum, which suggests that two dopamine circuits in the brain (nigrostriatal and mesolimbic pathways), responsible for motor function and pleasure respectively, are potentially affected by exercise.
These preliminary results show why exercise is specifically beneficial for patients with Parkinson’s disease and why people feel better after exercise. In clinical practice, adding exercise to the regular treatment routine for people with Parkinson’s disease is becoming more common, and the results from this study continue to validate the use of exercise as an added approach.
Exercise should be encouraged for majority of patients (when it is safe to do so). The duration, intensity and type of exercise will vary from patient to patient, but the goal for patients should be to increase their activity level to improve their motor function and mood.
NEURO CON: Did any demographic (ie, age, race/ethnicity) or socioeconomic factors play a role in the outcomes?
MS: The subjects recruited for this study were from a convenience sample of patients that volunteered from the clinic, so we did not look directly at demographics or socioeconomic factors in this study. The groups were slightly different in age (~6 years), which may have a small impact on the results, and there is a higher prevalence of Parkinson disease in men, which was reflected in our sample.
Socioeconomic factors could be barriers for people with Parkinson’s disease, who may not have access to services such as physiotherapy, personal training, or exercise equipment. However, even simple types of exercise, such as walking, can still be effective. It is better to be active and doing something, rather than not.
NEURO CON: Do you feel that current guidelines for treating Parkinson disease are in-line with your findings? If not, how should the guidelines be changed?
MS: The addition of exercise into treatment plans for people with Parkinson’s disease is becoming more widespread. Many groups in the United States and Canada are coming out with Parkinson’s-disease-specific exercise guidelines, which is fantastic. However, to maximize the benefits of exercise, I would suggest using exercise in addition to the neurologist-prescribed treatment plan, not using it as a monotherapy. Additionally, the exercise needs to be suitable and enjoyable for the individual. The exercise needs to be tailored to the goals, limitations, and wants of each individual. Most of all, the individual should enjoy the exercise otherwise they will not do it.
NEURO CON: What is the next step in your research?
MS: This study was the pilot study for a larger double-blinded, randomized control trial looking at the direct effects of exercise on dopamine release and function in people with Parkinson’s disease. The results from the larger trial should be out shortly.
NEURO CON: What is the No. 1 unanswered question in Parkinson disease research?
MS: Clinically, I think it is, “How can we diagnosis Parkinson’s disease before the onset of motor symptoms?” There is an urgent need for accurate, inexpensive, and objective biomarkers for Parkinson’s disease. If we can diagnosis people before symptoms emerge, we can intervene with a variety of therapies, including exercise, and have a fighting chance against the disease.
Scientifically, I think the most important unanswered question is, “Why are dopamine cells specifically targeted in Parkinson’s disease?” If we can understand the physiology underlying preferential cell loss in the brain, it may reveal novel therapeutic targets or the involvement of other complex systems such as the microbiome into the Parkinson’s disease puzzle.
Reference:
- Sacheli MA, Murray DK, Vafai N, et al. Habitual exercisers versus sedentary subjects with Parkinson's disease: multimodal PET and fMRI study [published online October 30, 2018]. Mov Disord. doi:10.1002/mds.27498.