A new stem cell derived tool for studying brain diseases

Sergiu Pasca’s three-dimensional culture makes it possible to watch how three different brain-cell types – oligodendrocytes (green), neurons (magenta) and astrocytes (blue) – interact in a dish as they do in a developing human  brain.
Courtesy of the Pasca lab

Neurological diseases are among the most daunting diagnoses for a patient to receive, because they impact how the individual interacts with their surroundings. Central to our ability to provide better treatment options for these patients, is scientists’ capability to understand the biological factors that influence disease development and progression. Researchers at the Stanford University School of Medicine have made an important step in providing neuroscientists a better tool to understand the brain.

While animal models are excellent systems to study the intricacies of different diseases, the ability to translate any findings to humans is relatively limited. The next best option is to study human stem cell derived tissues in the laboratory. The problem with the currently available laboratory-derived systems for studying the brain, however, is the limited longevity and diversity of neuronal cell types. Dr. Sergiu Pasca’s team was able to overcome these hurdles, as detailed in their study, published in the journal Nature Neuroscience.

A new approach

Specifically, Dr. Pasca’s group developed a method to differentiate or transform skin derived human induced pluripotent stem cells (iPSCs – which are capable of becoming any cell type) into brain-like structures that mimic how oligodendrocytes mature during brain development. Oligodendrocytes are most well known for their role in myelinating neurons, in effect creating a protective sheath around the cell to protect its ability to communicate with other brain cells. Studying oligodendrocytes in culture systems is challenging because they arise later in brain development, and it is difficult to generate and maintain them with other cell types found in the brain.

These scientists circumvented this problem by using a unique combination of growth factors and nutrients to culture the oligodendrocytes, and found that they behaved very similarly to oligodendrocytes isolated from humans. Most excitingly, they observed that the stem cell-derived oligodendrocytes were able to myelinate other neurons in the culture system. Therefore they were both physically and functionally similar to human oligodendrocytes.

Importantly, the scientists were also able to generate astrocytes alongside the oligodendrocytes. Astrocytes perform many important functions such as providing essential nutrients and directing the electrical signals that help cells in the brain communicate with each other. In a press release, Dr. Pasca explains the importance of generating multiple cell types in this in vitro system:

“We now have multiple cell types interacting in one single culture. This permits us to look close-up at how the main cellular players in the human brain are talking to each other.”

This in vitro or laboratory-developed system has the potential to help scientists better understand oligodendrocytes in the context of diseases such as multiple sclerosis and cerebral palsy, both of which stem from improper myelination of brain nerve cells.

This work was partially supported by a CIRM grant.

CIRM-funded research is helping unlock the secrets behind “chemo brain”

chemo brain

Every year millions of Americans undergo chemotherapy. The goal of the treatment is to destroy cancer, but along the way more than half of the people treated lose something else. They suffer from something called “chemo brain” which causes problems with thinking and memory. In some cases it can be temporary, lasting a few months. In others it can last years.

Now a CIRM-funded study by researchers at Stanford has found what may be behind chemo brain and identifying potential treatments.

In an article on the Stanford Medicine News Center, senior author Michelle Monje said:

“Cognitive dysfunction after cancer therapy is a real and recognized syndrome. In addition to existing symptomatic therapies — which many patients don’t know about — we are now homing in on potential interventions to promote normalization of the disorders induced by cancer drugs. There’s real hope that we can intervene, induce regeneration and prevent damage in the brain.”

The team first looked at the postmortem brains of children, some of whom had undergone chemotherapy and some who had not. The chemotherapy-treated brains had far fewer oligodendrocyte cells, a kind of cell important in protecting nerve cells in the brain.

Next the team injected methotrexate, a commonly used chemotherapy drug, into mice and then several weeks later compared the brains of those mice to untreated mice. They found that the brains of the treated mice had fewer oligodendrocytes and that the ones they had were in an immature state, suggested the chemo was blocking their development.

The inner changes were also reflected in behavior. The treated mice had slower movement, showed more anxiety, and impaired memory compared to untreated mice; symptoms that persisted for up to six months after the injections.

As if that wasn’t enough, they also found that the chemo affected other cells in the brain, creating a kind of cascade effect that seemed to amplify the impaired memory and other cognitive functions.

However, there is some encouraging news in the study, which is published in the journal Cell. The researchers gave the treated mice a drug to reverse some of the side effects of methotrexate, and that seemed to reduce some of the cognitive problems the mice were having.

Monje says that’s where her research is heading next.

“If we understand the cellular and molecular mechanisms that contribute to cognitive dysfunction after cancer therapy, that will help us develop strategies for effective treatment. It’s an exciting moment.”

 

Adding the missing piece: “mini-brain” method now includes important cell type

Although studying brain cells as a single layer in petri dishes has led to countless ground-breaking discoveries in neurobiology, it’s pretty intuitive that a two-dimensional “lawn” of cells doesn’t fully represent what’s happening in our complex, three-dimensional brain.

In the past few years, researchers have really upped their game with the development of brain organoids, self-organizing balls of cells that more accurately mimic the function of particular parts of the brain’s anatomy. Generating brain organoids from induced pluripotent stem cells (iPSCs) derived from patient skin samples is revolutionizing the study of brain diseases (see our previous blog stories here, here and here.)

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Tiny brain organoid spheres in petri dishes. Image: Case Western

This week, Case Western researchers reported in Nature Methods about an important improvement to the organoid technique that includes all the major cell types found in the cerebral cortex, the outer layer of the brain responsible for critical functions like our memory, language, and consciousness. The new method incorporates oliogodendrocytes, a cell type previously missing from the “mini-cortexes”. Oliogodendrocytes make myelin, a mix of proteins and fats that form a protective wrapping around nerve connections. Not unlike the plastic coating around an electrical wire, myelin is crucial for a neuron’s ability to send and receive signals from other neurons. Without the myelin, those signals short-circuit. It’s this breakdown in function that causes paralysis in multiple sclerosis patients and spinal cord injury victims.

With these new and improved organoids in hand, the researchers can now look for novel therapeutic strategies that could boost myelin production. In fact, the researchers generated brain organoids using iPSCs derived from patients with Pelizaeus-Merzbacher disease, a rare but fatal inherited myelin disorder. Each patient had a different mutation and an analysis of each organoid pointed to potential targets for drug treatments.

Dr. Mayur Madhavan, a co-first author on the study, explained the big picture implications of their new method in a press release:

Mayur Madhavan, PhD

“These organoids provide a way to predict the safety and efficacy of new myelin therapeutics on human brain-like tissue in the laboratory prior to clinical testing in humans.”

 

 

Stem cell treatment for spinal cord injury offers improved chance of independent life for patients

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Kris Boesen, CIRM spinal cord injury clinical trial patient works to strengthen his upper body. (Photo/Greg Iger)

A spinal cord injury is devastating, changing a person’s life in a heartbeat. In the past there was little that doctors could do other than offer pain relief and physical therapy to try and regain as much muscle function as possible. That’s why the latest results from the CIRM-supported Asterias Biotherapeutics spinal cord injury trial are so encouraging.

Asterias is transplanting what they call AST-OPC1 cells into patients who have suffered injuries that left them paralyzed from the neck down.  AST-OPC1 are oligodendrocyte progenitor cells, which develop into cells that support and protect nerve cells in the central nervous system, the area damaged in spinal cord injury. It’s hoped the treatment will restore connections at the injury site, allowing patients to regain some movement and feeling.

The latest results seem to suggest they are doing just that.

In a news release, Asterias reports that of the 25 patients treated in this clinical trial none have experienced serious side effects. They also reported that magnetic resonance imaging (MRI) tests show that more than 95 percent of the patients have shown evidence of what’s called “tissue matrix” at the injury site. This is encouraging because it suggests the implanted cells are engrafting and helping prevent a cavitation, a serious process that often occurs in spinal cord injuries and can lead to permanent loss of muscle and sensory function plus chronic pain.

The study also shows that after six months:

  • 100 percent of the patients in Group 5 (who received 20 million cells) have recovered at least one motor level (for example increased ability to use their arms) on at least one side
  • Two patients in Group 5 recovered one motor level on both sides
  • Altogether four of the 25 patients have recovered two or more motor levels on at least one side.

Not surprisingly Ed Wirth, the Chief Medical Officer at Asterias, was pleased with the results:

“The results from the study remain encouraging as the six-month follow-up data continued to demonstrate a positive safety profile and show that the AST-OPC1 cells are successfully engrafting in patients.”

While none of the patients are able to walk, just regaining some use of their arms or hands can have a hugely important impact on their quality of life and their ability to lead an independent life. And, because lifetime costs of taking care of someone who is paralyzed from the neck or chest down can run as high as $5 million, anything that increases a patient’s independence can have a big impact on those costs.

The impact of this research is helping change the lives of the patients who received it. One of those patients is Jake Javier. We have blogged about Jake several times over the last two years and recently showed this video about his first year at Cal Poly and how Jake is turning what could have been a life-ending event into a life-affirming one.

 

“A limitless future”: young crash victim regains hand, finger movement after CIRM-funded trial

Back in March, we reported on Asterias Biotherapeutics’ exciting press release stating that its CIRM-funded stem cell-based therapy for spinal cord injury had shown improvement in six out of the six clinical trial patients receiving a ten million cell dose. What’s even more exciting is hearing stories about the positive impact of that data on specific people’s lives. People like Lucas Lindner of Eden, Wisconsin.

Lucas Lindner was left paralyzed below the chin after a truck accident last May. Photo: Fox6Now, Milwaukee

Just over a year ago, Lucas headed out in his truck on a Sunday morning to pick up some doughnuts for his grandmother. Along the way, he suddenly saw a deer in the road and, in swerving to avoid hitting the animal, Lucas’ truck flipped over. He was thrown through the window and suffered a severe spinal cord injury leaving him without the use of his arms and legs.

Linder was the 2nd person to receive a 10 million dose of Asterias’ CIRM-funded stem cell-based therapy for spinal cord injury. Video still: Fox6Now, Milwaukee

Earlier this month, Lucas was featured in a local Milwaukee TV news report that highlights his incredible recovery since participating in the Asterias trial shortly after his accident. Surgeons at Medical College of Wisconsin – one of the clinical trial sites – injected 10 million AST-OPC1 cells into the site of the spinal cord injury a few inches below his skull. The AST-OPC1 product contains oligodendrocyte progenitor cells, which when fully matured are thought to help restore nerve signaling in the frayed spinal cord nerve cells.

Lucas was just the second person nationally to receive the 10 million cell dose, and since that time, he’s regained movement in his arms, hands and fingers. This improvement may seem moderate to an outside observer, but for Lucas, it’s life changing because it gives him the independence to pursue his dreams of working in the IT and electronics fields:

“Now that I have near 100% full range on all of my fingers, that pretty much brings everything I ever wanted to do back. It lets you contribute to society. Words can’t express how amazing it feels…The future really is limitless,” he said during the TV new segment.

While regaining movement spontaneously without a stem cell treatment is not unheard of, the fact that all six of the trial participants receiving 10 million cells had improvements suggests the stem cell-based therapy is having a positive impact. We’re hopeful for further good news later this year when Asterias expects to provide more safety and efficacy data on participants given the 10 million cell dose as well as others who received the maximum 20 million cell dose.

First spinal cord injury trial patient gets maximum stem cell dose

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Kris Boesen, CIRM spinal cord injury clinical trial patient.

There comes a pivotal point in every experiment where you say “ok, now we are going to see if this really works.” We may be at that point in the clinical trial we are funding to see if stem cells can help people with spinal cord injuries.

Today Asterias Biotherapeutics announced they have given the first patient in the clinical trial the highest dose of 20 million cells. The therapy was administered at Santa Clara Valley Medical Center (SCVMC) in San Jose, California where Jake Javier – a young man who was treated at an earlier stage of the trial – was treated. You can read Jake’s story here.

The goal of the trial is to test the safety of transplanting three escalating doses of AST-OPC1 cells. These are a form of cell called oligodendrocyte progenitors, which are capable of becoming several different kinds of nerve cells, some of which play a supporting role and help protect nerve cells in the central nervous system – the area damaged in spinal cord injury.

In a news release, Dr. Edward Wirth, Asterias’ Chief Medical Officer, says this could be a crucial phase in the trial:

“We have been very encouraged by the early clinical efficacy and safety data for AST-OPC1, and we now look forward to evaluating the 20 million cell dose in complete cervical spinal cord injury patients. Based on extensive pre-clinical research, this is in the dosing range where we would expect to see optimal clinical improvement in these patients.”

To be eligible, individuals have to have experienced a severe neck injury in the last 30 days, one that has left them with no sensation or movement below the level of their injury, and that means they have typically lost all lower limb function and most hand and arm function.

In the first phase individuals were given 2 million cells. This was primarily to make sure that this approach was safe and wouldn’t cause any problems for the patients. The second phase boosted that dose to ten million cells. That was thought to be about half the therapeutic dose but it seemed to help all those enrolled. By 90 days after the transplant all five patients treated with ten million cells had shown some level of recovery of at least one motor level, meaning they had regained some use of their arms and/or hands on at least one side of their body. Two of the patients experienced an improvement of two motor levels. Perhaps the most impressive was Kris Boesen, who regained movement and strength in both his arms and hands. He says he is even experiencing some movement in his legs.

All this is, of course, tremendously encouraging, but we also have to sound a note of caution. Sometimes individuals experience spontaneous recovery after an accident like this. The fact that all five patients in the 10 million cell group did well suggests that this may be more than just a coincidence. That’s why this next group, the 20 million cell cohort, is so important.

As Steve McKenna, Chief of the Trauma Center at SCVMC, says; if we are truly going to see an improvement in people’s condition because of the stem cell transplant, this is when we would expect to see it:

“The early efficacy results presented in September from the 10 million cell AIS-A cohort were quite encouraging, and we’re looking forward to seeing if those meaningful functional improvements are maintained through six months and beyond. We are also looking forward to seeing the results in patients from the higher 20 million cell AST-OPC1 dose, as well as results in the first AIS-B patients.”

For more information about the Asterias clinical trial, including locations and eligibility requirements, go here: www.clinicaltrials.gov, using Identifier NCT02302157, and at the SCiStar Study Website (www.SCiStar-study.com).

We can never talk about this clinical trial without paying tribute to a tremendous patient advocate and a great champion of stem cell research, Roman Reed. He’s the driving force behind the Roman Reed Spinal Cord Injury Research Act  which helped fund the pioneering research of Dr. Hans Keirstead that laid the groundwork for this clinical trial.