Stories that caught our eye: An antibody that could make stem cell research safer; scientists prepare for clinical trial for Parkinson’s disease; and the stem cell scientist running for Congress

Antibody to make stem cells safer:

There is an old Chinese proverb that states: ‘What seems like a blessing could be a curse’. In some ways that proverb could apply to stem cells. For example, pluripotent stem cells have the extraordinary ability to turn into many other kinds of cells, giving researchers a tool to repair damaged organs and tissues. But that same ability to turn into other kinds of cells means that a pluripotent stem cell could also turn into a cancerous one, endangering someone’s life.

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Researchers at the A*STAR Bioprocessing Technology Institute: Photo courtesy A*STAR

Now researchers at the Agency for Science, Technology and Research (A*STAR) in Singapore may have found a way to stop that happening.

When you change, or differentiate, stem cells into other kinds of cells there will always be some of the original material that didn’t make the transformation. Those cells could turn into tumors called teratomas. Scientists have long sought for a way to identify pluripotent cells that haven’t differentiated, without harming the ones that have.

The team at A*STAR injected mice with embryonic stem cells to generate antibodies. They then tested the ability of the different antibodies to destroy pluripotent stem cells. They found one, they called A1, that did just that; killing pluripotent cells but leaving other cells unharmed.

Further study showed that A1 worked by attaching itself to specific molecules that are only found on the surface of pluripotent cells.

In an article on Phys.Org Andre Choo, the leader of the team, says this gives them a tool to get rid of the undifferentiated cells that could potentially cause problems:

“That was quite exciting because it now gives us a view of the mechanism that is responsible for the cell-killing effect.”

Reviving hope for Parkinson’s patients:

In the 1980’s and 1990’s scientists transplanted fetal tissue into the brains of people with Parkinson’s disease. They hoped the cells in the tissue would replace the dopamine-producing cells destroyed by Parkinson’s, and stop the progression of the disease.

For some patients the transplants worked well. For some they produced unwanted side effects. But for most they had little discernible effect. The disappointing results pretty much brought the field to a halt for more than a decade.

But now researchers are getting ready to try again, and a news story on NPR explained why they think things could turn out differently this time.

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Viviane Tabar, MD; Photo courtesy Memorial Sloan Kettering Cancer Center

Viviane Tabar, a stem cell researcher at Memorial Sloan Kettering Cancer Center in New York, says in the past the transplanted tissue contained a mixture of cells:

“What you were placing in the patient was just a soup of brain. It did not have only the dopamine neurons, which exist in the tissue, but also several different types of cells.”

This time Tabar and her husband, Lorenz Studer, are using only cells that have been turned into the kind of cell destroyed by the disease. She says that will, hopefully, make all the difference:

“So you are confident that everything you are putting in the patient’s brain will consist of  the right type of cell.”

Tabar and Studer are now ready to apply to the Food and Drug Administration (FDA) for permission to try their approach out in a clinical trial. They hope that could start as early as next year.

Hans runs for Congress:

Keirstead

Hans Keirstead: Photo courtesy Orange County Register

Hans Keirstead is a name familiar to many in the stem cell field. Now it could become familiar to a lot of people in the political arena too, because Keirstead has announced he’s planning to run for Congress.

Keirstead is considered by some to be a pioneer in stem cell research. A CIRM grant helped him develop a treatment for spinal cord injury.  That work is now in a clinical trial being run by Asterias. We reported on encouraging results from that trial earlier this week.

Over the years the companies he has founded – focused on ovarian, skin and brain cancer – have made him millions of dollars.

Now he says it’s time to turn his sights to a different stage, Congress. Keirstead has announced he is going to challenge 18-term Orange County Republican Dana Rohrabacher.

In an article in the Los Angeles Times, Keirstead says his science and business acumen will prove important assets in his bid for the seat:

“I’ve come to realize more acutely than ever before the deficits in Congress and how my profile can actually benefit Congress. I’d like to do what I’m doing but on a larger stage — and I think Congress provides that, provides a forum for doing the greater good.”

 

 

 

 

 

 

 

 

 

Nine months in, stem cell-based therapy for spinal cord injury continues to improve paralyzed patients’ lives

If you’ve been following the Stem Cellar blog this year, then you must be as encouraged as we are with Asterias Biotherapeutics’ CIRM-funded clinical trial, which is testing an embryonic stem cell-based therapy for spinal cord injury.

astopc1Over many months, we’ve covered the company’s string of positive announcements that their cell therapy product – called AST-OPC1 – appears safe, is doing what is it’s supposed to after injection into the damaged spinal cord, and shows signs of restoring upper body function at 3 and 6 months after treatment. We’ve also written about first-hand accounts from some of the clinical trial participants who describe their remarkable recoveries.

That streak of good news continues today with Asterias’ early morning press release. The announcement summarizes 9-month results for a group of six patients who received an injection of 10 million AST-OPC1 cells 2 to 4 weeks after their injury (this particular trial is not testing the therapy on those with less recent injuries). In a nut shell, their improvements in arm, hand and finger movement seen at the earlier time points have persisted and even gotten better at 9 months.

Two motors levels = a higher quality of life
These participants sustained severe spinal cord injuries in the neck, leading to a loss of feeling and movement in their body from the neck down. To quantify the results of the cell therapy, researchers refer to “motor levels” of improvement. These levels correspond to an increasing number of motor, or movement, abilities. For a spinal cord injury victim paralyzed from the neck down, recovering two motor levels of function can mean the difference between needing 24-hour a day home care versus dressing, feeding and bathing themselves. The impact of this level of improvement cannot be overstated. As mentioned in the press release, regaining these abilities, “can result in lower healthcare costs, significant improvements in quality of life, increased ability to engage in activities of daily living, and increased independence.”

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9-month follow-up results of Asterias’ spinal cord injury trial. Patients treated with stem cell-based therapy (green line) have greater movement recovery compared to historical data from 62 untreated patients (Blue dotted line). Image: Asterias Biotherapeutics.

With the new 9-month follow-up data, the clinical researchers have confirmed that 3 out of the 6 (50%) patients show two motor levels of improvement. This result is up from 2 of 6 patients at the earlier time points. And all six patients have at least one motor level of improvement up through 9 months post-treatment. Now, make no mistake, spontaneous recovery from spinal cord injuries does occur. But historical data collected from 62 untreated patients show that only 29% reached two motor levels of improvement after 12-months.

As you can imagine, the Asterias team is optimistic about these latest results. Here’s what Chief Medical Officer, Dr. Edward Wirth had to say:

Edward-Wirth

Edward Wirth
Photo: Asterias

“The new efficacy results show that previously reported meaningful improvements in arm, hand and finger function in the 10 million cell cohort treated with AST-OPC1 cells have been maintained and in some patients have been further enhanced even 9 months following dosing. We are increasingly encouraged by these continued positive results, which are remarkable compared with spontaneous recovery rates observed in a closely matched untreated patient population.”

Equally encouraging is the therapy’s steady safety profile with no serious adverse events reported through the 9-month follow up.

Looking ahead
Dr. Jane Lebkowski, Asterias’ President of R&D and Chief Scientific Officer, will be presenting these data today during the International Society for Stem Cell Research (ISSCR) 2017 Annual Meeting held in Boston. Asterias expects to share more results later this fall after all six patients complete their 12-month follow-up visit.

The clinical trial is also treating another group of patients with a maximum dose of 20 million cells. The hope is that this cohort will show even more effectiveness.

For the sake of the more than 17,000 people who are incapacitated by a severe spinal cord injury each year, let’s hope the streak of good news continues.

Stories that caught our eye: color me stem cells, delivering cell therapy with nanomagnets, and stem cell decisions

Nanomagnets: the future of targeted stem cell therapies? Your blood vessels are made up of tightly-packed endothelial cells. This barrier poses some big challenges for the delivery of drugs via the blood. While small molecules are able make their way through the small gaps in the blood vessel walls, larger drug molecules, including proteins and cells, are not able to penetrate the vessel to get therapies to diseased areas.

This week, researchers at Rice University report in Nature Communications on an ingenious technique using tiny magnets that may overcome this drug delivery problem.

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At left, the nanoparticles are evenly distributed among the microtubules that help give the cells their shape. At right, after a magnetic field is applied, the nanoparticles are pulled toward one end of the cells and change their shapes. Credit: Laboratory of Biomolecular Engineering and Nanomedicine/Rice University

Initial studies showed that adding magnetic nanoparticles to the endothelial cells and then applying a magnetic field affected the cells’ internal scaffolding, called microtubules. These structures are responsible for maintaining the tight cell to cell connections. The team took the studies a step further by growing the cells in specialized petri dishes containing tiny, tube-shaped channels. Applying a magnetic field to the cells caused the cell-cell junctions to form gaps, making the blood vessel structures leaky. Simply turning off the magnetic field closed up the gaps within a few hours.

Though a lot of research remains, the team aims to apply this on-demand induction of cell leakiness along with adding the magnetic nanoparticles to stem cell therapy products to help target the treatment to specific area. In a press release, team leader Dr. Gang Bao spoke about possible applications to arthritis therapy:

“The problem is how to accumulate therapeutic stem cells around the knee and keep them there. After injecting the nanoparticle-infused cells, we want to put an array of magnets around the knee to attract them.”

To differentiate or not differentiate: new insights During the body’s development, stem cells must differentiate, or specialize, into functional cells – like liver, heart, brain. But once that specialization occurs, the cells lose their pluripotency, or the ability to become any type of cell. So, stem cells must balance the need to differentiate with the need to make copies of itself to maintain an adequate supply of stem cells to complete the development process. And even after a fully formed baby is born, it’s still critical for adult stem cells to balance the need to regenerate damaged tissue versus stashing away a pool of stem cells in various organs for future regeneration and replacement of damaged or diseased tissues.

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Visualizing activation of Nanog gene activity (bright green spot) within cell nucleus. 
Image: Courtesy of Bony De Kumar, Ph.D., and Robb Krumlauf, Ph.D., Stowers Institute for Medical Research

A report this week in the Proceedings of the National Academy of Sciences finds evidence that the two separate processes – differentiation and pluripotency – directly communicate with each other as way to ensure a proper balance between the two states.

The study, carried out by researchers at Stowers Institute for Medical Research in Kansas City, Missouri, focused on the regulation of two genes: Nanog and Hox. Nanog is critical for maintaining a stem cell’s ability to become a specialized cell type. In fact, it’s one of the four genes initially used to reprogram adult cells back into induced pluripotent stem cells. The Hox gene family is responsible for generating a blueprint of the body plan in a developing embryo. Basically, the pattern of Hox gene activity helps generate the body plan, basically predetermining where the various body parts and organs will form.

Now, both Nanog and Hox proteins act by binding to DNA and turning on a cascade of other genes that ultimately maintain pluripotency or promote differentiation. By examining these other genes, the researchers were surprised to find that both Nanog and Hox were bound to both the pluripotency and differentiation genes. They also found that Nanog and Hox can directly inhibit each other. Taken together, these results suggest that exquisite control of both processes occurs cross regulation of gene activity.

Dr. Robb Krumlauf one of authors on the paper talked about the significance of the result in a press release:

“Over the past 10 to 20 years, biologists have shown that cells are actively assessing their environment, and that they have many fates they can choose. The regulatory loops we’ve found show how the dynamic nature of cells is being maintained.”

Color me stem cells Looking to improve your life and the life of those around you? Then we highly recommend you pay a visit to today’s issue of Right Turn, a regular Friday feature of  Signals, the official blog of CCRM, Canada’s public-private consortium supporting the development of regenerative medicine technologies.

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Collage sample of CCRM’s new coloring sheets. Image: copyright CCRM 2017

As part of an public outreach effort they have created four new coloring sheets that depict stem cells among other sciency topics. They’ve set up a DropBox link to download the pictures so you can get started right away.

Adult coloring has swept the nation as the hippest new pastime. And it’s not just a frivolous activity, as coloring has been shown to have many healthy benefits like reducing stressed and increasing creativity. Just watch any kid who colors. In fact, share these sheet with them, it’s intended for children too.

Throwback Thursday: Progress to a Cure for Diseases of Blindness

Welcome back to our “Throwback Thursday” series on the Stem Cellar. Over the years, we’ve accumulated an arsenal of exciting stem cell stories about advances towards stem cell-based cures for serious diseases. This month we’re featuring stories about CIRM-funded clinical trials for blindness.

2017 has been an exciting year for two CIRM-funded clinical trials that are testing stem cell-based therapies for diseases of blindness. A company called Regenerative Patch Technologies (RPT) is transplanting a sheet of embryonic stem cell-derived retinal support cells into patients with the dry form of age-related macular degeneration, a disease that degrades the eye’s macula, the center of the retina that controls central vision. The other trial, sponsored by a company called jCyte, is using human retinal progenitor cells to treat retinitis pigmentosa, a rare genetic disease that destroys the light-sensing cells in the retina, causing tunnel vision and eventually blindness.

 

Both trials are in the early stages, testing the safety of their respective stem cell therapies. But the teams are hopeful that these treatments will stop the progression of or even restore some form of vision in patients. In the past few months, both RPT and jCyte have shared exciting news about the progress of these trials which are detailed below.

Macular Degeneration Trial Gets a New Investor

In April, RPT announced that they have a new funding partner to further develop their stem cell therapy for age-related macular degeneration (AMD). They are partnering with Japan’s Santen Pharmaceutical Company, which specializes in developing ophthalmology or eye therapies.

AMD is the leading cause of blindness in elderly people and is projected to affect almost 200 million people worldwide by 2020. There is no cure or treatment that can restore vision in AMD patients, but stem cell transplants offer a potential therapeutic option.

RPT believes that their newfound partnership with Santen will accelerate the development of their stem cell therapy and ultimately fulfill an unmet medical need. RPT’s co-founder, Dr. Dennis Clegg, commented in a CIRM news release, “the ability to partner with a global leader in ophthalmology like Santen is very exciting. Such a strong partnership will greatly accelerate RPT’s ability to develop our product safely and effectively.”

This promising relationship highlights CIRM’s efforts to partner our clinical programs with outside investors to boost their chance of success. It also shows confidence in the future success of RPT’s stem cell-based therapy for AMD.

Retinitis Pigmentosa Trial Advances to Phase 2 and Receives RMAT Status

In May, the US Food and Drug Administration (FDA) approved jCyte’s RP trial for Regenerative Medicine Advanced Therapy (RMAT) status, which could pave the way for accelerated approval of this stem cell therapy for patients with RP.

RMAT is a new status established under the 21st Century Cures Act – a law enacted by Congress in December of 2016 to address the need for a more efficient regulatory approval process for stem cell therapies that can treat serious or life-threatening diseases. Trial sponsors of RMAT designated therapies can meet with the FDA earlier in the trial process and are eligible for priority review and accelerated approval.

jCyte’s RMAT status is well deserved. Their Phase 1 trial was successful, proving the treatment was safe and well-tolerated in patients. More importantly, some of the patients revealed that their sight has improved following their stem cell transplant. We’ve shared the inspiring stories of two patients, Rosie Barrero and Kristin Macdonald, previously on the Stem Cellar.

Rosie Barrero

Kristin MacDonald

Both Rosie and Kristin were enrolled in the Phase 1 trial and received an injection of retinal progenitor cells in a single eye. Rosie said that she went from complete darkness to being able to see shapes, colors, and the faces of her family and friends. Kristin was the first patient treated in jCyte’s trial, and she said she is now more sensitive to light and can see shapes well enough to put on her own makeup.

Encouraged by these positive results, jCyte launched its Phase 2 trial in April with funding from CIRM. They will test the same stem cell therapy in a larger group of 70 patients and monitor their progress over the next year.

Progress to a Cure for Blindness

We know very well that scientific progress takes time, and unfortunately we don’t know when there will be a cure for blindness. However, with the advances that these two CIRM-funded trials have made in the past year, our confidence that these stem cell treatments will one day benefit patients with RP and AMD is growing.

I’ll leave you with an inspiring video of Rosie Barrero about her experience with RP and how participating in jCytes trial has changed her life. Her story is an important reminder of why CIRM exists and why supporting stem cell research in particular, and research in general, is vital for the future health of patients.


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Stem cell study shows how smoking attacks the developing liver in unborn babies

smoking mom

It’s no secret that smoking kills. According to the Centers for Disease Control and Prevention (CDC) smoking is responsible for around 480,000 deaths a year in the US, including more than 41,000 due to second hand smoke. Now a new study says that damage can begin in utero long before the child is born.

Previous studies had suggested that smoking could pose a serious risk to a fetus but those studies were done in petri dishes in the lab or using animals so the results were difficult to extrapolate to humans.

Researchers at the University of Edinburgh in Scotland got around that problem by using embryonic stem cells to explore how the chemicals in tobacco can affect the developing fetus. They used the embryonic stem cells to develop fetal liver tissue cells and then exposed those cells to a cocktail of chemicals known to be found in the developing fetus of mothers who smoke.

Dangerous cocktail

They found that this chemical cocktail proved far more potent, and damaged the liver far more, than individual chemicals. They also found it damaged the liver of males and females in different ways.  In males the chemicals caused scarring, in females it was more likely to negatively affect cell metabolism.

There are some 7,000 chemicals found in cigarette smoke including tar, carbon monoxide, hydrogen cyanide, ammonia, and radioactive compounds. Many of these are known to be harmful by themselves. This study highlights the even greater impact they have when combined.

Long term damage

The consequences of exposing a developing fetus to this toxic cocktail can be profound, including impaired growth, premature birth, hormonal imbalances, increased predisposition to metabolic syndrome, liver disease and even death.

The study is published in the Archives of Toxicology.

In a news release Dr. David Hay, one of the lead authors, said this result highlights yet again the dangers posed to the fetus by women smoking while pregnant or being exposed to secondhand smoke :

“Cigarette smoke is known to have damaging effects on the foetus, yet we lack appropriate tools to study this in a very detailed way. This new approach means that we now have sources of renewable tissue that will enable us to understand the cellular effect of cigarettes on the unborn foetus.”

“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.

ViaCyte Advances Cell Replacement Therapy for High Risk Type 1 Diabetes

San Diego regenerative medicine company ViaCyte announced this week that the Food and Drug Administration (FDA) approved their Investigational New Drug (IND) Application for PEC-Direct, a cell-based therapy to treat patients at risk for severe complications caused by type 1 diabetes. In the US, IND approval is the final regulatory step required before a therapy can be tested in clinical trials.

PEC-Direct is a combination therapy consisting of cells encapsulated in a device that aims to replace the insulin-producing islet cells of the pancreas destroyed in patients with type 1 diabetes. The device contains human stem cell-derived pancreatic progenitor cells that develop into insulin-secreting cells when the device is placed under the patient’s skin. Ports on the surface of the device allow blood vessels from the host to directly contact the cells within, allowing for engraftment of the transplanted cells and for their maturation into islet cells.  These cells can sense and regulate blood glucose levels by secreting the hormones found in islets, including insulin.

ViaCyte’s PEC-Direct device allows a patient’s blood vessels to integrate and make contact with the transplanted cells.

Because PEC-Direct allows for “direct vascularization”, in effect connecting the device to the blood system, patients will need to take immunosuppressive drugs to prevent rejection of the donor cells. ViaCyte is therefore testing this therapy in patients who are at risk for serious complications associated with type 1 diabetes like severe hypoglycemia where a patient’s blood sugar is so low they need immediate medical assistance.

Severe hypoglycemia can occur because people with diabetes must inject insulin to control elevated blood sugar, but the injections can exceed the patients’ needs. The resulting low blood sugar can lead to dizziness, irregular heartbeat, and unconsciousness, even death. In some cases, sufferers are not aware of their hypoglycemia symptoms, putting them at increased risk of these life-threatening complications.

ViaCyte’s President and CEO, Dr. Paul Laikind, explained in a news release,

Paul Laikind

“While insulin therapy transformed type 1 diabetes from a death sentence to a chronic illness, it is far from a cure. Type 1 diabetes patients continue to deal with the daily impact of the disease and remain at risk for often severe long-term complications.  This is especially true for the patients with high-risk type 1 diabetes, who face challenges such as hypoglycemia unawareness and life-threatening severe hypoglycemic episodes.  These patients have a particularly urgent unmet medical need and could benefit greatly from cell replacement therapy.”

Approximately 140,000 people in the US and Canada suffer from this form of high-risk diabetes. These patients qualify for islet transplants from donated cadaver tissue. But because donor islets are in limited supply, ViaCyte Clinical Advisor, Dr. James Shapiro at the University of Alberta, believes PEC-Direct will address this issue by providing an unlimited supply of cells.

“Islet transplants from scarce organ donors have offered great promise for those with unstable, high-risk type 1 diabetes, but the procedure has many limitations.  With an unlimited supply of new islets that the stem cell-derived therapy promises, we have real potential to benefit far more patients with islet cell replacement.”

The company’s preclinical research on PEC-Direct, leading up to the FDA’s IND approval, was funded by a CIRM late stage preclinical grant. ViaCyte now plans to launch a clinical trial this year that will evaluate the safety and efficacy of PEC-Direct in the US and Canada. They will enroll approximately 40 patients at multiple clinical trial centers including the University of Alberta in Edmonton, the University of Minnesota, and UC San Diego. The trial will test whether the device is safe and whether the transplanted cells can produce enough insulin to relieve patients of insulin injections and hypoglycemic events.

ViaCyte has another product called PEC-Encap, a different implantable device that contains the same cells but protects these cells from the patient’s immune system. The device is being tested in a CIRM-funded Phase 1/2a trial, and ViaCyte is currently collaborating with W. L. Gore & Associates to improve the design of PEC-Encap to improve consistency of engraftment in patients.

Positively good news from Asterias for CIRM-funded stem cell clinical trial for spinal cord injury

AsteriasWhenever I give a talk on stem cells one of the questions I invariably get asked is “how do you know the cells are going where you want them to and doing what you want them to?”

The answer is pretty simple: you look. That’s what Asterias Biotherapeutics did in their clinical trial to treat people with spinal cord injuries. They used magnetic resonance imaging (MRI) scans to see what was happening at the injury site; and what they saw was very encouraging.

Asterias is transplanting what they call AST-OPC1 cells into patients who have suffered recent injuries that have 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.

Taking a closer look

Early results suggest the therapy is doing just that, and now follow-up studies, using MRIs, are adding weight to those findings.

The MRIs – taken six months after treatment – show that the five patients given a dose of 10 million AST-OPC1 cells had no evidence of lesion cavities in their spines. That’s important because often, after a spinal cord injury, the injury site expands and forms a cavity, caused by the death of nerve and support cells in the spine, that results in permanent loss of movement and function below the site, and additional neurological damage to the patient.

Another group of patients, treated in an earlier phase of the clinical trial, showed no signs of lesion cavities 12 months after their treatment.

Positively encouraging

In a news release, Dr. Edward Wirth, the Chief Medical Officer at Asterias, says this is very positive:

“These new follow-up results based on MRI scans are very encouraging, and strongly suggest that AST-OPC1 cells have engrafted in these patients post-implantation and have the potential to prevent lesion cavity formation, possibly reducing long-term spinal cord tissue deterioration after spinal cord injury.”

Because the safety data is also encouraging Asterias is now doubling the dose of cells that will be transplanted into patients to 20 million, in a separate arm of the trial. They are hopeful this dose will be even more effective in helping restore movement and function in patients.

We can’t wait to see what they find.

Stem cell stories that caught our eye: spinal cord injury trial keeps pace; SMART cells make cartilage and drugs

CIRM-funded spinal cord injury trial keeping a steady pace

Taking an idea for a stem cell treatment and developing it into a Food and Drug Administration-approved cell therapy is like running the Boston Marathon because it requires incremental progress rather than a quick sprint. Asterias Biotherapeutics continues to keep a steady pace and to hit the proper milestones in its race to develop a stem cell-based treatment for acute spinal cord injury.


Just this week in fact, the company announced an important safety milestone for its CIRM-funded SciStar clinical trial. This trial is testing the safety and effectiveness of AST-OPC1, a human embryonic stem cell-derived cell therapy that aims to regenerate some of the lost movement and feeling resulting from spinal cord injuries to the neck.

Periodically, an independent safety review board called the Data Monitoring Committee (DMC) reviews the clinical trial data to make sure the treatment is safe in patients. That’s exactly what the DMC concluded as its latest review. They recommended that treatments with 10 and 20 million cell doses should continue as planned with newly enrolled clinical trial participants.

About a month ago, Asterias reported that six of the six participants who had received a 10 million cell dose – which is transplanted directly into the spinal cord at the site of injury – have shown improvement in arm, hand and finger function nine months after the treatment. These outcomes are better than what would be expected by spontaneous recovery often observed in patients without stem cell treatment. So, 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 the 20 million cell dose.

It’s a two-fer: SMART cells that make cartilage and release anti-inflammation drug
“It’s a floor wax!”….“No, it’s a dessert topping!”
“Hey, hey calm down you two. New Shimmer is a floor wax and a dessert topping!”

Those are a few lines from the classic Saturday Night Live skit that I was reminded of when reading about research published yesterday in Stem Cell Reports. The clever study generated stem cells that not only specialize into cartilage tissue that could help repair arthritic joints but the cells also act as a drug dispenser that triggers the release of a protein that dampens inflammation.

Using CRISPR technology, a team of researchers led by Farshid Guilak, PhD, at Washington University School of Medicine in St. Louis, rewired stem cells’ genetic circuits to produce an anti-inflammatory arthritis drug when the cells encounter inflammation. The technique eventually could act as a vaccine for arthritis and other chronic conditions. Image: ELLA MARUSHCHENKO

The cells were devised by a research team at Washington University School of Medicine in St. Louis. They started out with skin cells collected from the tails of mice. Using the induced pluripotent stem cell technique, the skin cells were reprogrammed into an embryonic stem cell-like state. Then came the ingenious steps. The team used the CRISPR gene-editing method to create a negative feedback loop in the cells’ inflammation response. They removed a gene that is activated by the potent inflammatory protein, TNF-alpha and replaced it with a gene that blocks TNF-alpha. Analogous experiments were carried out with another protein called IL-1.

Rheumatoid arthritis often affects the small joints causing painful swelling and disfigurement. Image: Wikipedia

Now, TNF-alpha plays a key role in triggering inflammation in arthritic joints. But this engineered cell, in the presence of TNF-alpha, activates the production of a protein that inhibits the actions of TNF-alpha. Then the team converted these stem cells into cartilage tissue and they went on to show that the cartilage was indeed resistant to inflammation. Pretty smart, huh? In fact, the researchers called them SMART cells for “Stem cells Modified for Autonomous Regenerative Therapy.” First author Dr. Jonathan Brunger summed up the approach succinctly in a press release:

“We hijacked an inflammatory pathway to create cells that produced a protective drug.”

This type of targeted treatment of arthritis would have a huge advantage over current anti-TNF-alpha therapies. Arthritis drugs like Enbrel, Humira and Remicade are very effective but they block the immune response throughout the body which carries an increased risk for serious infections and even cancer.

The team is now testing the cells in animal models of rheumatoid arthritis as well as other inflammation disorders. Those results will be important to determine whether or not this approach can work in a living animal. But senior Dr. Farshid Guilak also has an eye on future applications of SMART cells:

“We believe this strategy also may work for other systems that depend on a feedback loop. In diabetes, for example, it’s possible we could make stem cells that would sense glucose and turn on insulin in response. We are using pluripotent stem cells, so we can make them into any cell type, and with CRISPR, we can remove or insert genes that have the potential to treat many types of disorders.”

Stem cell stories that caught our eye: developing the nervous system, aging stem cells and identical twins not so identical

Here are the stem cell stories that caught our eye this week. Enjoy!

New theory for how the nervous system develops.

There’s a new theory on the block for how the nervous system is formed thanks to a study published yesterday by UCLA stem cell scientists in the journal Neuron.

The theory centers around axons, thin extensions projecting from nerve cells that transmit electrical signals to other cells in the body. In the developing nervous system, nerve cells extend axons into the brain and spinal cord and into our muscles (a process called innervation). Axons are guided to their final destinations by different chemicals that tell axons when to grow, when to not grow, and where to go.

Previously, scientists believed that one of these important chemical signals, a protein called netrin 1, exerted its influence over long distances in a gradient-like fashion from a structure in the developing nervous system called the floor plate. You can think of it like a like a cell phone tower where the signal is strongest the closer you are to the tower but you can still get some signal even when you’re miles away.

The UCLA team, led by senior author and UCLA professor Dr. Samantha Butler, questioned this theory because they knew that neural progenitor cells, which are the precursors to nerve cells, produce netrin1 in the developing spinal cord. They believed that the netrin1 secreted from these progenitor cells also played a role in guiding axon growth in a localized manner.

To test their hypothesis, they studied neural progenitor cells in the developing spines of mouse embryos. When they eliminated netrin1 from the neural progenitor cells, the axons went haywire and there was no rhyme or reason to their growth patterns.

Left: axons (green, pink, blue) form organized patterns in the normal developing mouse spinal cord. Right: removing netrin1 results in highly disorganized axon growth. (UCLA Broad Stem Cell Research Center/Neuron)

A UCLA press release explained what the scientists discovered next,

“They found that neural progenitors organize axon growth by producing a pathway of netrin1 that directs axons only in their local environment and not over long distances. This pathway of netrin1 acts as a sticky surface that encourages axon growth in the directions that form a normal, functioning nervous system.”

Like how ants leave chemical trails for other ants in their colony to follow, neural progenitor cells leave trails of netrin1 in the spinal cord to direct where axons go. The UCLA team believes they can leverage this newfound knowledge about netrin1 to make more effective treatments for patients with nerve damage or severed nerves.

In future studies, the team will tease apart the finer details of how netrin1 impacts axon growth and how it can be potentially translated into the clinic as a new therapeutic for patients. And from the sounds of it, they already have an idea in mind:

“One promising approach is to implant artificial nerve channels into a person with a nerve injury to give regenerating axons a conduit to grow through. Coating such nerve channels with netrin1 could further encourage axon regrowth.”

Age could be written in our stem cells.

The Harvard Gazette is running an interesting series on how Harvard scientists are tackling issues of aging with research. This week, their story focused on stem cells and how they’re partly to blame for aging in humans.

Stem cells are well known for their regenerative properties. Adult stem cells can rejuvenate tissues and organs as we age and in response to damage or injury. However, like most house hold appliances, adult stem cells lose their regenerative abilities or effectiveness over time.

Dr. David Scadden, co-director of the Harvard Stem Cell Institute, explained,

“We do think that stem cells are a key player in at least some of the manifestations of age. The hypothesis is that stem cell function deteriorates with age, driving events we know occur with aging, like our limited ability to fully repair or regenerate healthy tissue following injury.”

Harvard scientists have evidence suggesting that certain tissues, such as nerve cells in the brain, age sooner than others, and they trigger other tissues to start the aging process in a domino-like effect. Instead of treating each tissue individually, the scientists believe that targeting these early-onset tissues and the stem cells within them is a better anti-aging strategy.

David Sadden, co-director of the Harvard Stem Cell Institute.
(Jon Chase/Harvard Staff Photographer)

Dr. Scadden is particularly interested in studying adult stem cell populations in aging tissues and has found that “instead of armies of similarly plastic stem cells, it appears there is diversity within populations, with different stem cells having different capabilities.”

If you lose the stem cell that’s the best at regenerating, that tissue might age more rapidly.  Dr. Scadden compares it to a game of chess, “If we’re graced and happen to have a queen and couple of bishops, we’re doing OK. But if we are left with pawns, we may lose resilience as we age.”

The Harvard Gazette piece also touches on a changing mindset around the potential of stem cells. When stem cell research took off two decades ago, scientists believed stem cells would grow replacement organs. But those days are still far off. In the immediate future, the potential of stem cells seems to be in disease modeling and drug screening.

“Much of stem cell medicine is ultimately going to be ‘medicine,’” Scadden said. “Even here, we thought stem cells would provide mostly replacement parts.  I think that’s clearly changed very dramatically. Now we think of them as contributing to our ability to make disease models for drug discovery.”

I encourage you to read the full feature as I only mentioned a few of the highlights. It’s a nice overview of the current state of aging research and how stem cells play an important role in understanding the biology of aging and in developing treatments for diseases of aging.

Identical twins not so identical (Todd Dubnicoff)

Ever since Takahashi and Yamanaka showed that adult cells could be reprogrammed into an embryonic stem cell-like state, researchers have been wrestling with a key question: exactly how alike are these induced pluripotent stem cells (iPSCs) to embryonic stem cells (ESCs)?

It’s an important question to settle because iPSCs have several advantages over ESCs. Unlike ESCs, iPSCs don’t require the destruction of an embryo so they’re mostly free from ethical concerns. And because they can be derived from a patient’s cells, if iPSC-derived cell therapies were given back to the same patient, they should be less likely to cause immune rejection. Despite these advantages, the fact that iPSCs are artificially generated by the forced activation of specific genes create lingering concerns that for treatments in humans, delivering iPSC-derived therapies may not be as safe as their ESC counterparts.

Careful comparisons of DNA between iPSCs and ESCs have shown that they are indeed differences in chemical tags found on specific spots on the cell’s DNA. These tags, called epigenetic (“epi”, meaning “in addition”) modifications can affect the activity of genes independent of the underlying genetic sequence. These variations in epigenetic tags also show up when you compare two different preparations, or cell lines, of iPSCs. So, it’s been difficult for researchers to tease out the source of these differences. Are these differences due to the small variations in DNA sequence that are naturally seen from one cell line to the other? Or is there some non-genetic reason for the differences in the iPSCs’ epigenetic modifications?

Marian and Vivian Brown, were San Francisco’s most famous identical twins. Photo: Christopher Michel

A recent CIRM-funded study by a Salk Institute team took a clever approach to tackle this question. They compared epigenetic modifications between iPSCs derived from three sets of identical twins. They still found several epigenetic variations between each set of twins. And since the twins have identical DNA sequences, the researchers could conclude that not all differences seen between iPSC cell lines are due to genetics. Athanasia Panopoulos, a co-first author on the Cell Stem Cell article, summed up the results in a press release:

“In the past, researchers had found lots of sites with variations in methylation status [specific term for the epigenetic tag], but it was hard to figure out which of those sites had variation due to genetics. Here, we could focus more specifically on the sites we know have nothing to do with genetics. The twins enabled us to ask questions we couldn’t ask before. You’re able to see what happens when you reprogram cells with identical genomes but divergent epigenomes, and figure out what is happening because of genetics, and what is happening due to other mechanisms.”

With these new insights in hand, the researchers will have a better handle on interpreting differences between individual iPSC cell lines as well as their differences with ESC cell lines. This knowledge will be important for understanding how these variations may affect the development of future iPSC-based cell therapies.