Paving the way for a treatment for dementia

What happens in a stroke

When someone has a stroke, the blood flow to the brain is blocked. This kills some nerve cells and injures others. The damaged nerve cells are unable to communicate with other cells, which often results in people having impaired speech or movement.

While ischemic and hemorrhagic strokes affect large blood vessels and usually produce recognizable symptoms there’s another kind of stroke that is virtually silent. A ‘white’ stroke occurs in blood vessels so tiny that the impact may not be noticed. But over time that damage can accumulate and lead to a form of dementia and even speed up the progression of Alzheimer’s disease.

Now Dr. Tom Carmichael and his team at the David Geffen School of Medicine at UCLA have developed a potential treatment for this, using stem cells that may help repair the damage caused by a white stroke. This was part of a CIRM-funded study (DISC2-12169 – $250,000).

Instead of trying to directly repair the damaged neurons, the brain nerve cells affected by a stroke, they are creating support cells called astrocytes, to help stimulate the body’s own repair mechanisms.

In a news release, Dr. Irene Llorente, the study’s first author, says these astrocytes play an important role in the brain.

“These cells accomplish many tasks in repairing the brain. We wanted to replace the cells that we knew were lost, but along the way, we learned that these astrocytes also help in other ways.”

The researchers took skin tissue and, using the iPSC method (which enables researchers to turn cells into any other kind of cell in the body) turned it into astrocytes. They then boosted the ability of these astrocytes to produce chemical signals that can stimulate healing among the cells damaged by the stroke.

These astrocytes were then not only able to help repair some of the damaged neurons, enabling them to once again communicate with other neurons, but they also helped another kind of brain cell called oligodendrocyte progenitor cells or OPCs. These cells help make a protective sheath around axons, which transmit electrical signals between brain cells. The new astrocytes stimulated the OPCs into repairing the protective sheath around the axons.

Mice who had these astrocytes implanted in them showed improved memory and motor skills within four months of the treatment.  

And now the team have taken this approach one step further. They have developed a method of growing these astrocytes in large amounts, at very high quality, in a relatively short time. The importance of that is it means they can produce the number of cells needed to treat a person.

“We can produce the astrocytes in 35 days,” Llorente says. “This process allows rapid, efficient, reliable and clinically viable production of our therapeutic product.”

The next step is to chat with the Food and Drug Administration (FDA) to see what else they’ll need to do to show they are ready for a clinical trial.

The study is published in the journal Stem Cell Research.

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

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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