Science Friday

Teasing Apart The Causes And Early Signs Of Parkinson’s

19 min
Jan 16, 20263 months ago
Listen to Episode
Summary

This Science Friday episode explores the causes and early warning signs of Parkinson's disease, focusing on misfolded alpha-synuclein proteins and emerging evidence that environmental factors like pesticides, air pollution, and certain chemicals may trigger the disease. Experts discuss early detection biomarkers including loss of smell and REM sleep behavior disorder, and emphasize preventative approaches through exercise, diet, and environmental modifications.

Insights
  • Parkinson's is increasingly understood as a whole-body disease originating in the nose or gut, not just a brain disorder, challenging the traditional dopamine-centric model
  • Environmental toxins (pesticides like Paraquat, trichloroethylene from dry cleaners) show strong associations with Parkinson's, suggesting prevention through regulation could reduce cases
  • Early detection through biomarkers like smell loss and REM sleep behavior disorder can precede motor symptoms by decades, enabling earlier intervention strategies
  • No disease-slowing treatments currently exist, but exercise, sleep optimization, and lifestyle modifications show promise as preventative measures
  • Parkinson's likely has multiple causes rather than a single mechanism, requiring personalized biological staging for precise treatment development
Trends
Shift from symptomatic treatment to preventative medicine in neurodegenerative disease managementGrowing focus on environmental and occupational exposure as primary risk factors for Parkinson's diseaseDevelopment of non-invasive biomarkers (blood tests, tear fluid) to replace invasive spinal fluid testingBiological staging paradigm replacing traditional disease staging for personalized treatment planningIntegration of lifestyle interventions (exercise, diet, sleep) as evidence-based therapeutic approachesIncreased emphasis on community storytelling and patient advocacy in accelerating research and preventionRecognition of chemical regulation gaps as public health opportunities for disease preventionMulti-system disease model replacing single-organ disease frameworks in neurodegenerative research
Topics
Alpha-Synuclein Protein MisfoldingParkinson's Disease Early Detection BiomarkersEnvironmental Toxins and NeurodegenerationPesticide Exposure and Parkinson's RiskOlfactory Dysfunction as Prodromal SymptomREM Sleep Behavior DisorderTrichloroethylene Water ContaminationAir Pollution and Neurodegenerative DiseaseParkinson's Progression Marker Initiative (PPMI)Exercise as Therapeutic InterventionGenetic vs Environmental Parkinson's CausesWhole-Body Disease ModelClinical Trial Design for NeurodegenerationPreventative Neurology StrategiesBiomarker Validation and Accessibility
Companies
Parkinson's Foundation
Dr. Michael Oaken serves as medical advisor; organization supports research and patient advocacy for Parkinson's disease
Keck School of Medicine of USC
Dr. Emily Teman-Donfar is clinical assistant professor of neurology specializing in movement disorders
University of Florida Health
Dr. Michael Oaken is professor and executive director of the Norman Ficksell Institute for Neurological Diseases
People
Dr. Emily Teman-Donfar
Neurologist specializing in movement disorders; clinical assistant professor at USC Keck School of Medicine; PPMI res...
Dr. Michael Oaken
Professor and executive director of Norman Ficksell Institute; medical advisor for Parkinson's Foundation; author of ...
Flora Lichtman
Host of Science Friday episode; conducted interviews with Parkinson's disease experts
Quotes
"Parkinson's probably isn't one disease. Parkinson's is a whole body disease. There are probably a lot of different causes."
Dr. Michael Oaken
"Exercise is like a drug. It's now in major guidelines prescribed by every expert."
Dr. Michael Oaken
"We have to be very careful of going down that road too far. Because it might be that this is just a signal and a very important signal."
Dr. Michael Oaken
"The most important thing you can do is listen to people and ask people with Parkinson's to tell their stories."
Dr. Michael Oaken
"This biological staging is really important because some people may have certain positivity in some biomarkers and not in others."
Dr. Emily Teman-Donfar
Full Transcript
Rural Britain, is there any greater value out there than giga-clear full fiber from only 19 pounds a month? It's out of this world! Speed and reliability! Vast upload and downloadiness! Right here in Rural Tranquility! Saturn's Rings! Is that a bull? Gigaclear! Faster broadband for Rural Britain from only 19 pounds a month! Season C's apply! 18 month contract! Prices may rise during contract! Check availability at gigaclear.com Hey there, this is Flora Lichtman and you're listening to Science Friday. Each year around 90,000 people in the U.S. are diagnosed with Parkinson's disease. It's a neurodegenerative disease that can cause tremors and affect cognition. Scientists think that Parkinson's happens when some neurons, cells in the brain, get clogged up with clumps of protein and stop working right. Now, normally proteins aren't a problem, they're good, we need them, but when certain proteins misbehave and fold into weird shapes, trouble can start. Misfolding proteins are found in lots of neurodegenerative diseases like ALS and Huntington's disease and Alzheimer's, you've probably heard about plaques and tangles. Those are the protein clumps found in Alzheimer's. In Parkinson's, a protein called Alpha-Synuclein is thought to be the culprit. Misfolding, clumping, and spreading through the brain. So what gets this protein ball rolling and can it be stopped? That is what we're talking about today. Let me introduce my guests. Dr. Emily Teman-Donfar is a neurologist specializing in movement disorders. She's a clinical assistant professor of neurology at the Keck School of Medicine of USC. And Dr. Michael Oaken is a professor and executive director of the Norman Ficksell Institute for Neurological Diseases at University of Florida Health. He's also the medical advisor for the Parkinson's Foundation and he's written many books about Parkinson's. His latest is called The Parkinson's Plan, A New Path to Prevention and Treatment. Emily and Michael, welcome to Science Friday. Pleasure to be here. Thank you for having me. Michael, did I get that description right about the misfolded proteins causing problems? Yeah, so these proteins exist normally. And so when we have something called Alpha-Synuclein, you know, you need these things and they are important for regulation and for what we call homeostasis. And so when we think about, you know, Parkinson and Alzheimer's disease and ALS and these diseases that are degenerative, we think about them showing up in protein folding. It's a clue. It's a bread crumb that's telling us something is going on in this brain, in this body that is evoking. It's causing the body to have a response to say, hey, you're out of homeostasis. But what we have to be careful of is we have to be careful of the enticing idea that it's all these protein clumps, that they're the cause of everything. We have to be very careful of going down that road, you know, too far. Because it might be that this is just a signal and a very important signal. But I think we have to be really careful to ask ourselves, why does it start? Why does it spread? Why does it progress? And to be humble and say, we really don't have the answers to those questions yet. Emily, I think people are familiar with some of the later stage symptoms, tremors-impaired movement. In some cases, cognitive impairment. But you are studying some very early signs of Parkinson's and I know smell is one of them. What do we know about this? Yeah, so there's a very large observational study going on and has been going on since 2010 called the Parkinson's Progression Marker Initiative. And this study is including participants who have Parkinson's disease and those who are at risk of Parkinson's disease, what we call a prodromal participants. And these are people who have diminished sense of smell. We call hyposmia, which we think often predates motor symptoms like stiffness, slowness and tremor as you mentioned. And as well, we have seen that patients who have something called REM sleep behavior disorder, which is a sort of dream reenactment behavior. This can also precede some of the motor symptoms. Dream reenactment behavior like acting out your dreams while you're asleep? Yes, yes. This is something that is diagnosed based on a sleep study, but patients with Parkinson's, many will describe yelling out in their sleep, thrashing around. It's often noticed by their bed partners. How early are these signs showing up? So this can happen many years, even decades before motor symptoms can occur. And we know a large portion of people who have REM sleep behavior disorder, not everyone, but a large portion of them do go on to develop Parkinson's disease. And smell too? The smell loss too? Is that early? Yes, smell loss as well. And so not everybody who has smell loss will have Parkinson's disease, right? We see, you know, there may be many other reasons to have smell loss, but we do see in patients who have Parkinson's disease, a large portion of them before they develop motor symptoms will have had a diminished sense of smell. Michael, does the fact that it starts in the nose suggest that it is triggered by something we are breathing in? Yeah, so there are a number of theories on this, and it's not just the nose. So the nose would be one path to the potential start of Parkinson's. The other is the gut. And people talk about this as brain first, so coming through the nose or gut first, actually coming through, you know, through the stomach and through your gut. And we find these abnormal protein clumps that you talked about in both places. And one of the real amazing and mysterious things about Parkinson's is when we look at the genetics of Parkinson's, about 13 to 15 people out of every 100 have a single piece of DNA that is abnormal or mutated. And that causes their Parkinson's, but the vast majority of people don't have that single mutation. And so we are now shifting a lot of our science, a lot of our effort, a lot of our research toward trying to understand what environmental factors and environmental influences might be impacting Parkinson's, why it starts, why it spreads, why it progresses. And there are two areas that have really, you know, raised up in our radar of what could be going on. One is air pollution, and the other is pesticides and water. And so things that we take in from the environment seem to be related and have a high association for more cases of Parkinson's and other degenerative disorders that you mentioned as well. Which, what specifically? We worry about pesticides, so things like Paraquat as one example of a pesticide that is highly associated with Parkinson's disease. When we think about water, we think about triacloreal ethylene. And also we think about dry cleaners as being one of the big offenders. And this is also a chemical that's used to degrease. It's a chemical that's used in the airline industry. It's a chemical used by factories. But when folks throw it away, it actually gets into the water supply and can actually vaporize and get up into the brains of folks with Parkinson's disease. And so triaclorethaline is a chemical. And then in Alzheimer's disease, and in some cases of Parkinson's, it has a higher association with Alzheimer's as air pollution. And so we are beginning to shift our thinking to being more preventative as we see study after study showing us these associations. I mean, does this suggest that we could be preventing Parkinson's if we had different regulation around certain chemicals? So I believe this is true. You know, as we begin to uncover these associations, we have to be careful, right? Because Parkinson's probably isn't one disease. Parkinson's is a whole body disease. There are probably a lot of different causes. And so the question comes up is, do we have, you know, needless cases and can we spare this generation and the next? And I think the answer comes with the courage to follow the science and to do the experiment and to remove these things, especially when there are alternatives or ways that we can live better. We have to take a quick break. But when we come back, we're going to talk lots more about this, including about early warning signs. Don't go away. How does AI even work? Where does creativity come from? What's the secret to living longer? Ted Radio Hour explores the biggest questions with some of the world's greatest thinkers. They will surprise, challenge, and even change you. Listen to NPR's Ted Radio Hour wherever you get your podcasts. Okay, we're back. I'm talking with Dr. Emily Temmond-Donfar and Dr. Michael Oaken about Parkinson's disease. Emily, tell me about this longitudinal study you mentioned, PPMI. What are you trying to learn? So the goal of PPMI, it's really about early detection. Can we more accurately and do that? And also to speed development of new treatments. So it's really twofold in that goal. As we think about developing treatments to slow disease progression, with that we need to also think about how do we diagnose earlier and how do we diagnose earlier? With that, we need to also think about how do we diagnose earlier and more accurately? Is there a blood test for Parkinson's? Are there biomarkers you can measure? We don't have a blood test for Parkinson's, but we do have other biomarkers. And so that's what's been one of the challenges, is can we identify and validate biomarkers? Through this Parkinson's progression markers initiative, we've been able to validate Alpha-Synuclein Seeding Amplification Assay, which is a spinal fluid biomarker. But it's hard to obtain spinal fluid. It's not the most comfortable process for people. So we are still looking to identify other biomarkers that are more easily accessible, like in-tier fluid, blood samples. And how does the test work for participants? The participants in PPMI, they get a series of tests. So they actually have a lot of tests when they come into the office. They not only have clinical assessments done, they also undergo imaging studies, including dopamine transport imaging studies. And our goal is also, I think, ultimately to identify biomarkers and have some quantitative data with that so we can better track disease progression and response to treatment. How do you test smell loss? So there's actually a validated smell test where you can, participants can receive that in the mail and... Like a card that, you know, like markers with a smell. What should I be envisioning? Exactly, exactly. So it's sort of like if you can envision those scratch and sniff. So with those smell tests, they'll have different smells and they'll receive a score based on how well they did with each of the smells. Emily, if I find that I do have smell loss, does that mean I'm at higher risk that I have Parkinson's? It doesn't mean you already have it, but you may have a feature and this is part of what we're trying to understand. So not everybody with smell loss will go on to develop Parkinson's, but you may qualify to participate in the study in some form. But I wouldn't say, you know, if you have diminished sense of smell that you should necessarily be very concerned. You go on to have Parkinson's disease. It's something we're trying to understand better. Michael, do we understand how the sort of protein misfolding spreads? You know, if it's starting in the nose or the gut, why does it keep going? Yeah, so, you know, we actually don't know the answer to that question. And one of the other very interesting but also perplexing things for scientists is that everybody with Parkinson's disease doesn't have these abnormal synnuclein, alpha, you know, misfolding within their brains and we see differences in different types of genes, genetic forms of Parkinson's and not everybody. It's not a one size fits all. And so we have begun to rethink this disease and in fact, the idea that Parkinson's is just a disease of dopamine. We have now rethought that. We don't think Parkinson's disease is a disease just of the brain. We see it in the nerves outside the brain. We see it in the gut. We see it in the salivary glands. We see it in the skin. And so it's a whole body disease. Mmm. Do we have any treatment that can slow the progression of the disease now, Emily? No, we don't have any treatment as it stands now that we know will slow progression of the disease. There are other interventions that we emphasize, including things like regular physical activity, diet, these sorts of things that we know can have a really positive benefit overall. But as it stands now, we don't have a treatment that we know slows disease progression. This must be so frustrating for both of you who have devoted your lives to this. I mean, of course, it's devastating to patients, but it must also hit you hard. I'm very optimistic. I do think we were just talking about PPMI and the importance of these biomarkers. And it's really important, I think, in the context of building staging. One thing patients always come in and ask me is, what stage am I in? And that paradigm is shifting to this biological staging. And why that's really important is, as Dr. Oken was saying, putting into context all these different biomarkers. And some people may have certain positivity in some of the biomarkers and not in others. And putting that together to design clinical trials to develop more precise treatment plans for patients. This is really critical now. Michael, what about you? Are you optimistic? I am optimistic. I, you know, so as Emily said, we don't have the data yet as to what might slow disease progression. But we do know that certain things are really important. And study after study is showing that exercise, as Emily mentioned, is like a drug. It's now in major guidelines prescribed by every expert. So anybody who's listening should know that having an exercise regime, whether or not you can stand up, you know, or not, there are ways to exercise. Exercise is a very powerful drug. And there's data to suggest that it may, you know, have some effect in slowing the disease, although still debatable among scientists. Sleep is super important. And so I think we're entering an era of medicine where we can be more preventative. We can think about what we can do to prevent diseases, to try to stop them from developing. But even if you have a disease, the first thing you should do is remove some of these things from the environment. And improve your situation. So if you have Parkinson's disease, get a carbon water filter, you know, make sure that you have air purifiers around, particularly if you're in an urban area or an area without good air quality and wash your fruit and get those pesticides off of them. There's no reason we shouldn't be doing those simple things. Yeah. Well, I would love to see society at large work on some of these problems because we are in a time where health optimization is sort of the name of the game, that it's now everyone's individual responsibility to keep themselves healthy. And I guess just to push back slightly on that, I would love to see this as personally as a society-wide effort, you know. 100%. And so, you know, we all want this to go faster. And I think the way to make it go faster is for each one of us. And every time that I go on the road for the Parkinson's Foundation or talk about the book or talk about Parkinson's, I always tell the most important thing you can do is listen to people and ask people with Parkinson's to tell their stories. The more we tell the stories of each other, we are a community, we are a village, the better chance we're going to have to decrease the amount of time that we can get to prevention and we can get to reducing the numbers and the burden of this disease. So tell your story would be a key message. Emily and Michael, thank you so much for joining me today. Honored to be here. Thank you so much for the pleasure. Dr. Emily Teman-Donvar is a neurologist specializing in movement disorders. She's a clinical assistant professor of neurology at the Keck School of Medicine of USC. And Dr. Michael Oaken is a professor and executive director of the Norman Ficksell Institute for Neurological Diseases at University of Florida Health. He's also the medical advisor for the Parkinson's Foundation. This episode was produced by Annette Heist. And if you like the podcast, please rate and review the show wherever you listen. I want to thank listener Reformed Luddite who wrote, This is the first thing I listen to each morning. I especially enjoy getting to hear from the scientists themselves. Me too. Thank you for listening. See you next time. I'm Flora Lichtman. Thank you.