Parkinson’s Disease and Stem Cells

Lila Collins, PhD

A few weeks ago we held a Facebook Live “Ask the Stem Cell Team About Parkinson’s Disease” event. As you can imagine we got lots of questions but, because of time constraints, only had time to answer a few. Thanks to my fabulous CIRM colleagues, Dr. Lila Collins and Dr. Kent Fitzgerald, for putting together answers to some of the other questions. Here they are.

Kent Fitzgerald, PhD

Q: It seems like we have been hearing for years that stem cells can help people with Parkinson’s, why is it taking so long?

A: Early experiments in Sweden using fetal tissue did provide a proof of concept for the strategy of replacing dopamine producing cells damaged or lost in Parkinson’s disease (PD) . At first, this seemed like we were on the cusp of a cell therapy cure for PD, however, we soon learned based on some side effects seen with this approach (in particular dyskinesias or uncontrollable muscle movements) that the solution was not as simple as once thought. 

While this didn’t produce the answer it did provide some valuable lessons.

The importance of dopaminergic (DA) producing cell type and the location in the brain of the transplant.  Simply placing the replacement cells in the brain is not enough. It was initially thought that the best site to place these DA cells is a region in the brain called the SN, because this area helps to regulate movement. However, this area also plays a role in learning, emotion and the brains reward system. This is effectively a complex wiring system that exists in a balance, “rewiring” it wrong can have unintended and significant side effects. 

Another factor impacting progress has been understanding the importance of disease stage. If the disease is too advanced when cells are given then the transplant may no longer be able to provide benefit.  This is because DA transplants replace the lost neurons we use to control movement, but other connected brain systems have atrophied in response to losing input from the lost neurons. There is a massive amount of work (involving large groups and including foundations like the Michael J Fox Foundation) seeking to identify PD early in the disease course where therapies have the best chance of showing an effect.   Clinical trials will ultimately help to determine the best timing for treatment intervention.

Ideally, in addition to the cell therapies that would replace lost or damaged cells we also want to find a therapy that slows or stops the underlying biology causing progression of the disease.

So, I think we’re going to see more gene therapy trials including those targeting the small minority of PD that is driven by known mutations.  In fact, Prevail Therapeutics will soon start a trial in patients with GBA1 mutations. Hopefully, replacing the enzyme in this type of genetic PD will prevent degeneration.

And, we are also seeing gene therapy approaches to address forms of PD that we don’t know the cause, including a trial to rescue sick neurons with GDNF which is a neurotrophic factor (which helps support the growth and survival of these brain cells) led by Dr Bankiewicz  and trials by Axovant and Voyager, partnered with Neurocrine aimed at restoring dopamine generation in the brain.

 A small news report came out earlier this year about a recently completed clinical trial by Roche Pharma and Prothena. This addressed the build up in the brain of what are called lewy bodies, a problem common to many forms of PD. While the official trial results aren’t published yet, a recent press release suggests reason for optimism.  Apparently, the treatment failed to statistically improve the main clinical measurement, but other measured endpoints saw improvement and it’s possible an updated form of this treatment will be tested again in the hopes of seeing an improved effect.

Finally, I’d like to call attention to the G force trials. Gforce is a global collaborative effort to drive the field forward combining lessons learned from previous studies with best practices for cell replacement in PD.  These first-in-human safety trials to replace the dopaminergic neurons (DANs) damaged by PD have shared design features including identifying what the best goals are and how to measure those.

The CIRA trial, Dr Jun Takahashi

The NYSTEM PD trial, Dr Lorenz Studer

The EUROSTEMPD trial, Dr Roger Barker.

And the Summit PD trial, Dr Jeanne Loring of Aspen Neuroscience.

Taken together these should tell us quite a lot about the best way to replace these critical neurons in PD.

As with any completely novel approach in medicine, much validation and safety work must be completed before becoming available to patients

The current approach (for cell replacement) has evolved significantly from those early studies to use cells engineered in the lab to be much more specialized and representing the types believed to have the best therapeutic effects with low probability of the side effects (dyskinesias) seen in earlier trials. 

If we don’t really know the cause of Parkinson’s disease, how can we cure it or develop treatments to slow it down?

PD can now be divided into major categories including 1. Sporadic, 2. Familial. 

For the sporadic cases, there are some hallmarks in the biology of the neurons affected in the disease that are common among patients.  These can be things like oxidative stress (which damages cells), or clumps of proteins (like a-synuclein) that serve to block normal cell function and become toxic, killing the DA neurons. 

The second class of “familial” cases all share one or more genetic changes that are believed to cause the disease.  Mutations in genes (like GBA, LRRK2, PRKN, SNCA) make up around fifteen percent of the population affected, but the similarity in these gene mutations make them attractive targets for drug development.

CIRM has funded projects to generate “disease in a dish” models using neurons made from adults with Parkinson’s disease.   Stem cell-derived models like this have enabled not only a deep probing of the underlying biology in Parkinson’s, which has helped to identify new targets for investigation, but have also allowed for the testing of possible therapies in these cell-based systems. 

iPSC-derived neurons are believed to be an excellent model for this type of work as they can possess known familial mutations but also show the rest of the patients genetic background which may also be a contributing factor to the development of PD. They therefore contain both known and unknown factors that can be tested for effective therapy development.

I have heard of scientists creating things called brain organoids, clumps of brain cells that can act a little bit like a brain. Can we use these to figure out what’s happening in the brain of people with Parkinson’s and to develop treatments?

There is considerable excitement about the use of brain organoids as a way of creating a model for the complex cell-to-cell interactions in the brain.  Using these 3D organoid models may allow us to gain a better understanding of what happens inside the brain, and develop ways to treat issues like PD.

The organoids can contain multiple cell types including microglia which have been a hot topic of research in PD as they are responsible for cleaning up and maintaining the health of cells in the brain.  CIRM has funded the Salk Institute’s Dr. Fred Gage’s to do work in this area.

If you go online you can find lots of stem cells clinics, all over the US, that claim they can use stem cells to help people with Parkinson’s. Should I go to them?

In a word, no! These clinics offer a wide variety of therapies using different kinds of cells or tissues (including the patient’s own blood or fat cells) but they have one thing in common; none of these therapies have been tested in a clinical trial to show they are even safe, let alone effective. These clinics also charge thousands, sometimes tens of thousands of dollars these therapies, and because it’s not covered by insurance this all comes out of the patient’s pocket.

These predatory clinics are peddling hope, but are unable to back it up with any proof it will work. They frequently have slick, well-designed websites, and “testimonials” from satisfied customers. But if they really had a treatment for Parkinson’s they wouldn’t be running clinics out of shopping malls they’d be operating huge medical centers because the worldwide need for an effective therapy is so great.

Here’s a link to the page on our website that can help you decide if a clinical trial or “therapy” is right for you.

Is it better to use your own cells turned into brain cells, or cells from a healthy donor?

This is the BIG question that nobody has evidence to provide an answer to. At least not yet.

Let’s start with the basics. Why would you want to use your own cells? The main answer is the immune system.  Transplanted cells can really be viewed as similar to an organ (kidney, liver etc) transplant. As you likely know, when a patient receives an organ transplant the patient’s immune system will often recognize the tissue/organ as foreign and attack it. This can result in the body rejecting what is supposed to be a life-saving organ. This is why people receiving organ transplants are typically placed on immunosuppressive “anti-rejection “drugs to help stop this reaction. 

In the case of transplanted dopamine producing neurons from a donor other than the patient, it’s likely that the immune system would eliminate these cells after a short while and this would stop any therapeutic benefit from the cells.  A caveat to this is that the brain is a “somewhat” immune privileged organ which means that normal immune surveillance and rejection doesn’t always work the same way with the brain.  In fact analysis of the brains collected from the first Swedish patients to receive fetal transplants showed (among other things) that several patients still had viable transplanted cells (persistence) in their brains.

Transplanting DA neurons made from the patient themselves (the iPSC method) would effectively remove this risk of the immune system attack as the cells would not be recognized as foreign.

CIRM previously funded a discovery project with Jeanne Loring from Scripps Research Institute that sought to generate DA neurons from Parkinson’s patients for use as a potential transplant therapy in these same patients.   This project has since been taken on by a company formed, by Dr Loring, called Aspen Neuroscience.  They hope to bring this potential therapy into clinical trials in the near future.    

A commonly cited potential downside to this approach is that patients with genetic (familial) Parkinson’s would be receiving neurons generated with cells that may have the same mutations that caused the problem in the first place. However, as it can typically take decades to develop PD, these cells could likely function for a long time. and prove to be better than any current therapies.

Creating cells from each individual patient (called autologous) is likely to be very expensive and possibly even cost-prohibitive. That is why many researchers are working on developing an “off the shelf” therapy, one that uses cells from a donor (called allogeneic)would be available as and when it’s needed.

When the coronavirus happened, it seemed as if overnight the FDA was approving clinical trials for treatments for the virus. Why can’t it work that fast for Parkinson’s disease?

While we don’t know what will ultimately work for COVID-19, we know what the enemy looks like.  We also have lots of experience treating viral infections and creating vaccines.  The coronavirus has already been sequenced, so we are building upon our understanding of other viruses to select a course to interrupt it.  In contrast, the field is still trying to understand the drivers of PD that would respond to therapeutic targeting and therefore, it’s not precisely clear how best to modify the course of neurodegenerative disease.  So, in one sense, while it’s not as fast as we’d like it to be, the work on COVID-19 has a bit of a head start.

Much of the early work on COVID-19 therapies is also centered on re-purposing therapies that were previously in development.  As a result, these potential treatments have a much easier time entering clinical trials as there is a lot known about them (such as how safe they are etc.).  That said, there are many additional therapeutic strategies (some of which CIRM is funding) which are still far off from being tested in the clinic. 

The concern of the Food and Drug Administration (FDA) is often centered on the safety of a proposed therapy.  The less known, the more cautious they tend to be. 

As you can imagine, transplanting cells into the brain of a PD patient creates a significant potential for problems and so the FDA needs to be cautious when approving clinical trials to ensure patient safety.

Stem Cells for Parkinson’s Disease

While the world has been turned upside down by the coronavirus pandemic, the virus poses an increased threat to people with Parkinson’s disease (PD). Having a compromised immune system, particularly involving the lungs, means people with PD are at higher risk of some of the more dangerous complications of COVID-19. So, this seems like an appropriate time for CIRM to hold a special Facebook Live “Ask the Stem Cell Team” About Parkinson’s disease.

We are holding the event on Tuesday, May 5th at noon PDT.

The initial reason for the Facebook Live was the CIRM Board approving almost $8 million for Dr. Krystof Bankiewicz at Brain Neurotherapy Bio, Inc. to run a Phase 1 clinical trial targeting PD. Dr. Bankiewicz is using a gene therapy approach to promote the production of a protein called GDNF, which is best known for its ability to protect dopaminergic neurons, the kind of cell damaged by Parkinson’s. The approach seeks to increase dopamine production in the brain, alleviating PD symptoms and potentially slowing down the disease progress.

Dr. Bankiewicz will be joined by two of CIRM’s fine Science Officers, Dr. Lila Collins and Dr. Kent Fitzgerald. They’ll talk about the research targeting Parkinson’s that CIRM is funding plus other promising research taking place.

And we are delighted to have a late addition to the team. Our CIRM Board member and patient advocate for Parkinson’s disease, Dr. David Higgins. David has a long history of advocacy for PD and adds the invaluable perspective of someone living with PD.

As always, we want this to be as interactive as possible, so we want to get your questions. You can do this on the day, posting them alongside the live feed, or you can send them to us ahead of time at info@cirm.ca.gov. We’ll do our best to answer as many as we can on the day, and those we don’t get to during the broadcast we’ll answer in a later blog.

We look forward to seeing you there.

Can stem cells help people who have had a stroke? Ask the experts.

Stroke is the third leading cause of death and disability in the US. Every 45 seconds someone in the US has a stroke. Every year around 275,000 people die from a stroke many more survive but are often impaired by the brain attack. The impact is not just physical, but psychological and emotional. It takes an enormous toll on individuals and their families. So, it’s not surprising that there is a lot of research underway to try and find treatments to help people, including using stem cells.

That’s why CIRM is hosting a special Facebook Live ‘Ask the Stem Cell Team About Stroke event on Wednesday, March 25th at noon PDT. Just head over to our Facebook Page on the 25th at noon to hear from two great guests.

We will be joined by Dr. Tom Carmichael, a Professor of Neurology and the Co-Director of the UCLA Broad Stem Cell Center. He has a number of CIRM grants focused on helping repair the damage caused by strokes.

CIRM Senior Science Officer, Dr. Lila Collins, will also join us to talk about other stem cell research targeting stroke, its promise and some of the problems that still need to be overcome.

You will have a chance to ask questions of both our experts, either live on the day or by sending us questions in advance at info@cirm.ca.gov.

Can stem cells help people recovering from a stroke? You asked, and the experts answered

FacebookLive_AskExperts_Stroke_IMG_1656

We recently held our first ever Facebook Live event. It was focused on the use of stem cells and recovery from a stroke and featured three great guests: Dr. Gary Steinberg, chief of Neurosurgery at Stanford, Sonia Coontz, a patient of Dr. Steinberg’s, and CIRM’s own Science Officer Dr. Lila Collins.

We had an amazing response from people during the event and in the days since then with some 6,750 people watching the video and almost 1,000 people reacting by posting a comment or sharing it with friends. It was one of the most successful things we have ever done on Facebook so it’s not surprising that we plan on doing many more Facebook Live ‘Ask the Expert’ events in the future. We will post more details of that as we finalize them.

We tried to cover as many topics as possible during the hour but there were simply too many questions for us to get to all of them. So here is a recap of the key issues we covered, and a few we didn’t have a chance to answer.

Let’s start with Dr. Steinberg’s explanation of the research that led to his current clinical trial:

Dr. Steinberg: “I got interested in this about 18 years ago when I took human cells and transplanted them into rodent models of stroke. What we found was that when we transplanted those cells into the stroke region, the core of the stroke, they didn’t survive very well but when we moved them a few millimeters away from the stroke they not only survived but they migrated to the stroke.

The reason they migrate is that the stem cells have receptors on them that interact with chemicals given off by the stroke environment and that’s why they migrate to the stroke site. And when they get to the site they can turn into different kinds of cells. Very importantly we found these mice and rats that had behavioral problems – walking, moving – as a result of the stroke, we found we could improve their neurological outcomes with the stem cells.

With the help of CIRM, which has been very generous, we were fortunate enough to receive about $24 million in funding over the last 8 years, from 2010, to move this therapy into the clinic to understand the basic mechanisms of the recovery and to start clinical trials

One of the surprising things was that our initial notion was that the cells we transplanted into the brains would initially turn into the cells in the brain affected by the stroke and reconstitute those circuits. We were shocked to find that that was not what was happening, that only a few of the transplanted cells turned into neurons. The way they were recovering function was by secreting very powerful growth factors and molecules and proteins that enhanced native recovery or the ability of the normal brain to recover itself. Some of these processes included outgrowth of neurons, new connections, new synapses, not from the stem cells but from the native cells already in the brain.

This is not cell replacement but enhancing native recovery and, in a simple sense, what the cells are doing, we believe, is to change the adult brain, which has a hard time recovering from a stroke, into an infant brain and infants recover very well after a stroke.”

All this work was focused on ischemic strokes, where a blockage cuts off blood flow to the brain. But people like Cheryl Ward wanted to know: “Will this work for hemorrhagic stroke?” That’s where a blood vessel in the brain leaks or ruptures.

Dr. Steinberg: “I suspect we will be generalizing this therapy into hemorrhagic patients very, very soon and there’s no reason why it shouldn’t work there. The reason we didn’t start there is that 85% of strokes are ischemic and only 15% are hemorrhagic so it’s a smaller population but a very, very important population because when patients have a hemorrhage from a stroke they are often more seriously disabled than from ischemic.”

Dr. Lila Collins: “I would like to highlight one trial for hemorrhagic stroke with the Mayo Clinic and that’s using mesenchymal stem cells (normally found in bone marrow or blood). It’s an early stage, Phase 1 safety study in patients with recent cerebral hemorrhage.  They are looking at improvements in neurological function and patients have to be treated within 72 hours after the stroke.”

Dr. Steinberg explained that because it’s more difficult to enroll patients within 72 hours of a stroke that we may end up offering a combination of therapies spread out over months or even years.

Dr. Steinberg: “It may be that and we may figure this out in the next 5 to 10 years, that you might want to treat patients acutely (right away) with an intravenous therapy in the first 72 hours and then you might want to come in again sub-acutely within a few months, injecting the cells into the brain near the stroke, and then maybe come in chronically a few years later if there are still problems and place the cells directly in the brain. So, lots of ways to think about how to use this in the future.”

James Russell suffered a stroke in 2014 and wrote:

“My left side was affected. My vision was also impacted. Are any stroke patients being given stem cells seeing possible improvement in visual neglect?”

Dr. Steinberg: “We don’t know the answer to that yet, it’s quite possible. It’s true these vision circuits are not dead and could be resurrected. We have not targeted visual pathways in our work, we have targeted motor functions, but I would also be optimistic that we could target patients who have vision problems from stroke. It’s a very important area.

A number of people wondered if stem cells can help people recovering from a stroke can they also help people with other neurological conditions.

Hanifa Gaphoor asked “What about Parkinson’s disease?” and Ginnievive Patch wondered “Do you feel hopeful for neurological illnesses like Huntington’s disease and ALS? Dr. Steinberg was cautiously optimistic.

Dr. Steinberg: “We’ve extended this kind of treatment not just for ischemic stroke but into traumatic brain injury (TBI) and we just completed a trial for patients with chronic TBI or who have suffered a trauma to the brain. Many other indications may be possible. In fact, now that we know these circuits are not dead or irreversibly injured, we believe we could even extend this to neurodegenerative diseases like ALS, Parkinson’s, maybe even to Alzheimer’s disease in the future. So, lots of hope but we don’t want to oversell this, and we want to make sure this is done in a rigorous fashion.”

Several people had questions about using their own adipose, or fat stem cells, in therapies being offered at clinics around the US and in other countries. Cheri Hicks asked: “I’m curious if adipose stem cell being used at clinics at various places is helpful or beneficial?”

Dr. Steinberg: “I get emails or calls from patients every week saying should I go to Russia, India or Mexico and get stem cell transplants which are done not as part of a rigorous trial and I discourage patients from getting stem cells that are not being given in a controlled fashion. For one thing, patients have been getting hurt by these treatments in these clinics; they have developed tumors and infections and other problems. In many cases we don’t even know what the cells are, there’s not published information and the patients pay cash for this, of course.”

At CIRM we also worry about people going to clinics, in the US and in other countries, where they are getting therapies that have not been approved by the US Food and Drug Administration (FDA) or other appropriate regulatory bodies. That’s why we have created this page on our website to help people who want a stem cell therapy but don’t know what to look for in a clinical trial or what questions to ask to make sure it’s a legitimate trial, one that’s been given the go-ahead by the FDA.

Bret Ryan asked: “What becomes of the implanted cells?”

Dr. Steinberg: We found after transplanting the cells, one week after the transplant, we see a new abnormality in the premotor cortex, the area of the brain that controls motor function. We saw a new abnormality there or a new signal that disappears after a month and never comes back. But the size of that temporary abnormality after one week correlates very closely with the degree of recovery after six months, one year and two years.

One of the interesting things is that it doesn’t seem to be necessary for the cells to survive long term to have beneficial effects. The cells we used in the SanBio trial don’t survive more than a month and yet they seem to aid recovery function in our pilot studies which is sustained for years.”

And of course, many people, such as Karen Smart, wanted to know how they could get the therapy. Right now, the clinical trial is fully enrolled but Stanford is putting together a waiting list for future trials. If you are interested and would like more information, please email: stemcellstudy@stanford.edu.

Sonia Coontz, the patient who was also a key part of the Facebook Live event, has an amazing story to tell. She was left devastated, physically and emotionally, after having a stroke. But then she heard about Dr. Steinberg’s clinical trial and it changed her life. Here’s her story.

We were thrilled to receive all of your comments and questions during our first Facebook Live event. It’s this kind of dialogue between scientists, patients and the public that will be critical for the continued support of our mission to accelerate stem cell treatments to patients with unmet medical needs.

Due to the response, we plan to regularly schedule these “Ask the Expert” events. What disease area would you like us to focus on next time? Leave us a comment or email info@cirm.ca.gov