Parkinson's and Diabetes: Looking for the Connection
Mar 26, 2019 Cedars-Sinai Staff
Parkinson's disease is one of the most mysterious neurological conditions doctors treat.
As much as we know about the human body, the brain is elusive and full of uncharted territory.
What are you studying?
Dr. Tagliati: We are studying the potential benefits of a diabetes medication called liraglutide for patients with Parkinson's disease who do not have diabetes.
We want to see if patients can benefit from medication that is actually designed to treat insulin resistance. Previous studies have shown positive results using these types of medication; we want to improve on those studies.
Why are you studying this?
Dr. Tagliati: There is a long history of connection between diabetes, a condition that affects how the body processes sugar, and Parkinson's.
There are several studies showing that if you have diabetes, you seem to be more likely to develop Parkinson's disease. So, there's this idea that whatever is going on with diabetes—in particular with insulin resistance—might somehow affect the brain and lead to neurodegeneration.
We know from an earlier study we did here at Cedars-Sinai that out of 154 Parkinson's patients, 58% were insulin resistant. In order to keep their blood sugar—or blood glucose—at normal levels, their bodies needed more insulin, which is a sign of insulin resistance.
Knowing this, we asked ourselves, "Do these nondiabetic Parkinson's patients have problems processing sugar?" If they do, we suspect a medication to treat insulin resistance could help improve Parkinson's symptoms.
How are you studying this?
Dr. Tagliati: We have a phase 2 clinical trial that involves 57 Parkinson's patients. The trial will be for 2 years: one year on the medication or placebo, and one year of following up with the patients.
We are going to look at side effects and whether the patient feels better or not based on evaluations of their motor and non-motor symptoms before and after taking liraglutide.
In addition, we're going to see if their brains will handle sugar better based on a glucose PET scan. Finally, we're going to look at whether their brain is working better or not.
What are you hoping to achieve with this study?
Dr. Tagliati: This study has several goals.
The first immediate, obvious goal is to see if people feel better in the short-term by improving their symptoms while testing the safety of the drug in Parkinson's patients.
The second goal is to see if improvements persist after patients stop taking the medication at the end of the first year. If so, this would suggest potential disease modification and not only a response to actively being on medication. What we are looking for is a slowing down of the progression of disease, which is one of the holy grails of neurodegeneration research.
We're really trying to encompass several ambitious goals.
But above and beyond the immediate clinical outcome of the study drug, we want to learn more about this disease despite the clinical outcome. It would be amazing if we can put even one more piece of the puzzle in its place.