Muscles

Study could pave the way in reducing decline in muscle strength as people age 

/ Esteban Cortez / Leave a comment

A study by Stanford Medicine researchers in older mice may lead to treatments that help seniors regain muscle strength lost to aging.

Muscle stem cells—which are activated in response to muscle injury to regenerate damaged muscle tissue—lose their potency with age. A study from the National Health and Nutrition Examination Survey showed that five percent of adults aged 60 and over had weak muscle strength, and thirteen percent had intermediate muscle strength. 

Now, researchers at Stanford Medicine are seeing that old mice regain the leg muscle strength of younger animals after receiving an antibody treatment that targets a pathway mediated by a molecule called CD47.  

The study was published in Cell Stem Cell and is co-funded by the California Institute for Regenerative Medicine (CIRM).  

A Closer Look at CD47 

CD47 is a protein found on the surface of many cells in the body. Billed as the “don’t eat me” molecule, it is better known as a target for cancer immunotherapy. It’s common on the surface of many cancer cells and protects them from immune cells that patrol the body looking for dysfunctional or abnormal cells.  

Stanford researchers are finding that old muscle stem cells may use a similar approach to avoid being targeted by the immune system. 

It’s been difficult to determine why muscle stem cells lose their ability to divide rapidly in response to injury or exercise as they age. Dr. Ermelinda Porpiglia, the lead author of the study, used a technique called “single-cell mass cytometry” to study mouse muscle stem cells.  

Using the technique, Porpiglia focused on CD47, and found that the molecule was found at high levels on the surface of some muscle stem cells in older mice, but at lower levels in younger animals. Porpiglia also found that high levels of CD47 on the surface of muscle stem cells correlate with a decrease in their function.   

“This finding was unexpected because we primarily think of CD47 as an immune regulator,” Porpiglia said. “But it makes sense that, much like cancer cells, aged stem cells might be using CD47 to escape the immune system.” 

Testing an Antibody 

Further investigation revealed that a molecule called thrombospondin, which binds to CD47 on the surface of the muscle stem cells, suppresses the muscle stem cells’ activity.  

Porpiglia showed that an antibody that recognizes thrombospondin and blocks its ability to bind to CD47 dramatically affected the function of muscle stem cells. Cells from older animals divided more robustly when growing in a laboratory dish in the presence of the antibody, and when the antibody was injected into the leg muscles of old mice the animals developed bigger and stronger leg muscles than control animals.  

When given prior to injury, the antibody helped the aged animals recover in ways similar to younger mice. 

Porpiglia said, “We are hopeful that it might one day be possible to inject an antibody to thrombospondin at specific sites in the body to regenerate muscle in older people or to counteract functional problems due to disease or surgery.” 

These results are significant because they could one day make it possible to boost muscle recovery in humans after surgery and reduce the decline in muscle strength as people age, but researchers say more work is needed.  

“Rejuvenating the muscle stem cell population in older mice led to a significant increase in strength,” said Dr. Helen Blau, a senior author of the study. “This is a localized treatment that could be useful in many clinical settings, although more work needs to be done to determine whether this approach will be safe and effective in humans.” 

CIRM has previously funded work with researchers using CD47 that led to clinical trials targeting cancer. You can read about that work here and here. That work led to the creation of a company, Forty Seven Inc, which was eventually bought by Gilead for $4.9 billion.  

Read the original release by Krista Conger on the Stanford Medicine website. 

The power of the patient advocate: how a quick visit led to an $11M grant to fund a clinical trial

/ Kevin McCormack / 1 Comment

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Members of NFOSD visiting UC Davis in 2013

At the California Institute for Regenerative Medicine (CIRM) we are fortunate in having enough money to fund the most promising research to be tested in a clinical trial. Those are expensive projects, often costing tens of millions of dollars. But sometimes the projects that come to our Board start out years before in much more humble circumstances, raising money through patient advocates, tapping into the commitment and ingenuity of those affected by a disease, to help advance the search for a treatment.

That was definitely the case with a program the CIRM Board voted to approve yesterday, investing more than $11 million dollars to fund a Phase 2 clinical trial testing a cell therapy for dysphagia. That’s a debilitating condition that affects many people treated for head and neck cancer.

Patients with head and neck cancer often undergo surgery and/or radiation to remove the tumors. As a result, they may develop problems swallowing and this can lead to serious complications such as malnutrition, dehydration, social isolation, or a dependence on using a feeding tube. Patients may also inhale food or liquids into their lungs causing infections, pneumonia and death. The only effective therapy is a total laryngectomy where the larynx or voice box is removed, leaving the person unable to speak.

Dr. Peter Belafsky and his team at the University of California at Davis are developing a therapeutic approach using Autologous Muscle Derived Progenitor Cells (AMDC), cells derived from a biopsy of the patient’s own muscle, elsewhere in the body. Those AMDCs are injected into the tongue of the patient, where they fuse with existing muscle fibers to increase tongue strength and ability to swallow.

The $11,015,936 that Dr. Belafsky is getting from CIRM will enable them to test this approach in patients. But without grass roots support the program might never have made it this far.

Ed Steger is a long-term survivor of head and neck cancer, he’s also the President of the National Foundation of Swallowing Disorders (NFOSD). In 2007, after being treated for his cancer, Ed developed a severe swallowing disorder. It helped motivate him to push for better treatment options.

In 2013, a dozen swallowing disorder patients visited UC Davis to learn how stem cells might help people with dysphagia. (You can read about that visit here). Ed says: “We were beyond thrilled with the possibilities and drawing on patients and other UCD contacts our foundation raised enough funds to support a small UCD clinical trial under the guidance of Dr. Belafsky in mouse models that demonstrated these possibilities.”

A few years later that small funding by patients and their family members grew into a well-funded Phase I/II human clinical trial. Ed says the data that trial produced is helping advance the search for treatments.

“Skipping forward to the present, this has now blossomed into an additional $11 million grant, from CIRM, to continue the work that could be a game changer for millions of Americans who suffer annually from oral phase dysphagia. My hat is off to all those that have made this possible… the donors, patient advocates, and the dedicated committed researchers and physicians who are performing this promising and innovative research.”

Our hats are off to them too. Their efforts are making what once might have seemed impossible, a real possibility.

Recovery from muscle loss injuries hindered by immune cell conflicts

/ Katie Sharify / Leave a comment

During a game in 2018, Alex Smith suffered a compound fracture that broke both the tibia and fibula in his right leg. The gruesome injury aside, the former 49ers quarterback soon developed life-threatening necrotizing fasciitis — a rare bacterial infection — that resulted in sepsis and required him to undergo 17 surgeries.

In a battle to save his life and avoid amputating his leg, doctors had to remove a great deal of his muscle tissue leading to volumetric muscle loss (VML). When Smith returned to the field after nearly two years of recovery, many called his comeback a “miracle”. 

Skeletal muscle is one of the most dynamic tissues of the human body. It defines how we move and can repair itself after injury using stem cells. However, when significant chunks of muscle are destroyed through severe injury (e.g. gunshot wound) or excessive surgery (like that of Smith’s), VML overwhelms the regenerative capacity of the muscle stem cells.

Despite the prevalence of these injuries, no standardized evaluation protocol exists for the characterization and quantification of VML and little is understood about why it consistently overwhelms the body’s natural regenerative processes. Current treatment options include functional free muscle transfer and the use of advanced bracing designs.

However, new research from the University of Michigan (U-M) may have just discovered why tissues often fail to regenerate from traumatic muscle loss injuries.

When researchers from U-M collaborated with partners at Georgia Tech, Emory University and the University of Oregon to study VML injuries in mice, they found that that sometimes post-injury immune cells become dysregulated and prevent stem cell repair. In VML injuries that don’t heal, neutrophils — a type of white blood cell — remain at the injured site longer than normal meaning that they’re not doing their job properly.

In addition, researchers found that intercellular communication between neutrophils and natural killers cells impacted muscle stem cell-mediated repair. When neutrophils communicated with natural killer cells, they were essentially prompted to self-destruct.

The findings suggest that by altering how the two cell types communicate, different healing outcomes may be possible and could offer new treatment strategies that eventually restore function and prevent limb loss. The team of researchers hope that better treatments could mean that recovery from VML injuries is no longer considered a “miracle”.

To read the source release, click here.

How mRNA and CRISPR-Cas9 could treat muscle atrophy

/ Esteban Cortez / 1 Comment

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Researchers use mRNA to introduce the gene editor CRISPR-Cas9 into human muscle stem cells. These cells fused into multinucleated myotubes following mRNA-mediated CRISPR-Cas9 gene editing. A myosin heavy chain is seen in green and the nuclei in blue. Photo: Spuler Lab

A team of researchers from Experimental and Clinical Research Center (ECRC) has introduced the gene editor CRISPR-Cas9 into human muscle stem cells for the first time using messenger RNA (mRNA), potentially discovering a method suitable for therapeutic applications. 

The researchers are aiming to discover if this tool can repair mutations that lead to muscle atrophy in humans, and they are one step closer after finding that the method worked in mice suffering from the condition. But the method had a catch, ECRC researcher Helena Escobar says.  

“We introduced the genetic instructions for the gene editor into the stem cells using plasmids – which are circular, double-stranded DNA molecules derived from bacteria.” But plasmids could unintentionally integrate into the genome of human cells, which is also double stranded, and then lead to undesirable effects that are difficult to assess. “That made this method unsuitable for treating patients,” Escobar says.   

Getting mRNA Into Stem Cells

So the team set out to find a better alternative. They found it in the form of mRNA, a single-stranded RNA molecule that recently gained acclaim as a key component of two Covid-19 vaccines. 

To get the mRNA into the stem cells, the researchers used a process called electroporation, which temporarily makes cell membranes more permeable to larger molecules. “With the help of mRNA containing the genetic information for a green fluorescent dye, we first demonstrated that the mRNA molecules entered almost all the stem cells,” explains Christian Stadelmann, a doctoral student at ECRC.  

In the next step, the team used a deliberately altered molecule on the surface of human muscle stem cells to show that the method can be used to correct gene defects in a targeted manner.   

Paving the Way for a Clinical Trial 

Finally, the team tried out a tool similar to the CRISPR-Cas9 gene editor that does not cut the DNA, but only tweaks it at one spot with accuracy. In petri dish experiments, Stadelmann and his team were able to show that the corrected muscle stem cells are just as capable as healthy cells of fusing with each other and forming young muscle fibers. 

Their latest paper, which is appearing in the journal Molecular Therapy Nucleic Acids, paves the way for a clinical trial for patients with hereditary muscle atrophy. The team expects to enroll five to seven patients toward the end of the year. 

“Of course we cannot expect miracles,” says Simone Spuler, head of the Myology Lab at ECRC. “Sufferers who are in wheelchairs won’t just get up and start walking after the therapy. But for many patients, it is already a big step forward when a small muscle that is important for grasping or swallowing functions better again.” 

Read the source article here.

A personal reason to develop a better gene therapy

/ Kevin McCormack / 2 Comments

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Credit : Allison Dougherty, Broad Communications

For Sharif Tabebordbar, finding a gene therapy for genetic muscle wasting diseases was personal. When he was a teenager, his father was diagnosed with a rare genetic muscle disease that eventually left him unable to walk.

In an interview with the Broad Institute at MIT he said: “I watched my dad get worse and worse each day. It was a huge challenge to do things together as a family – genetic disease is a burden on not only patients but families. I thought: This is very unfair to patients and there’s got to be a way to fix this. That’s been my motivation during the 10 years that I’ve been working in the field of gene therapy.”

That commitment now seems to be paying off. In a study published in the journal Cell, Tabebordar and his team at MIT and Harvard showed how they have developed a new, safer and easier way to deliver genes to help repair wasting muscles.   

In earlier treatments targeting genetic muscle diseases, researchers used a virus to help deliver the gene that would correct the problem. However, to be effective they had to use high doses of the gene-carrying virus to ensure it reached as many muscles throughout the body as possible. But this meant that more of the payload often ended up in the liver and that led to severe side effects in some patients, even a few deaths.

The usual delivery method of these gene-correcting therapies is something called an adeno-associated virus (AAV), so Dr. Tabebordar set out to develop a new kind of AAV, one that would be safer for patients and more effective at tackling the muscle wasting.

They started by taking an adeno-associated virus called AAV9 and then set out about tweaking its capsid – that’s the outer shell that helps protect the virus and allows it to attach to another cell and penetrate it to deliver the corrected gene. They called this new viral vector MyoAAV and in tests it quickly showed it had an enhanced ability to deliver genes into cells.

The team showed that it not only was around 10 times more efficient at reaching muscle than other AAVs, but that it also reduces the amount that reaches the liver. This meant that MyoAAV could achieve impressive results in doses up to 250 times lower than those previously used.

In animal studies MyoAAV showed encouraging results in diseases like Duchenne Muscular Dystrophy and X-linked myotubular myopathy. Dr. Amy Wagers, a co-senior author of the study, says they are hopeful it will be equally effective in people.

“All of these results demonstrate the broad applicability of the MyoAAV vectors for delivery to muscle. These vectors work in different disease models and across different ages, strains and species, which demonstrates the robustness of this family of AAVs. We have an enormous amount of information about this class of vectors from which the field can launch many exciting new studies.”

A new way to evade immune rejection in transplanting cells

/ Kevin McCormack / 2 Comments
Immune fluorescence of HIP cardiomyocytes in a dish; Photo courtesy of UCSF

Transplanting cells or an entire organ from one person to another can be lifesaving but it comes with a cost. To avoid the recipient’s body rejecting the cells or organ the patient has to be given powerful immunosuppressive medications. Those medications weaken the immune system and increase the risk of infections. But now a team at the University of California San Francisco (UCSF) have used a new kind of stem cell to find a way around that problem.

The cells are called HIP cells and they are a specially engineered form of induced pluripotent stem cell (iPSC). Those are cells that can be turned into any kind of cell in the body. These have been gene edited to make them a kind of “universal stem cell” meaning they are not recognized by the immune system and so won’t be rejected by the body.

The UCSF team tested these cells by transplanting them into three different kinds of mice that had a major disease; peripheral artery disease; chronic obstructive pulmonary disease; and heart failure.

The results, published in the journal Proceedings of the National Academy of Science, showed that the cells could help reduce the incidence of peripheral artery disease in the mice’s back legs, prevent the development of a specific form of lung disease, and reduce the risk of heart failure after a heart attack.

In a news release, Dr. Tobias Deuse, the first author of the study, says this has great potential for people. “We showed that immune-engineered HIP cells reliably evade immune rejection in mice with different tissue types, a situation similar to the transplantation between unrelated human individuals. This immune evasion was maintained in diseased tissue and tissue with poor blood supply without the use of any immunosuppressive drugs.”

Deuse says if this does work in people it may not only be of great medical value, it may also come with a decent price tag, which could be particularly important for diseases that affect millions worldwide.

“In order for a therapeutic to have a broad impact, it needs to be affordable. That’s why we focus so much on immune-engineering and the development of universal cells. Once the costs come down, the access for all patients in need increases.”

Inspiring new documentary about stem cell research

/ Kevin McCormack / Leave a comment
Poster for the documentary “Ending Disease”

2020 has been, to say the very least, a difficult and challenging year for all of us. But while the focus of the world has, understandably, been on the coronavirus there was also some really promising advances in stem cell research. Those advances are captured in a great new documentary called Ending Disease.

The documentary is by Emmy award-winning filmmaker Joe Gantz. In it he follows ten people who are facing life-threatening or life-changing diseases and injuries and who turn to pioneering stem cell therapies for help.

It’s an inspiring documentary, one that reminds you of the real need for new treatments and the tremendous hope and promise of stem cell therapies. Here’s a look at a trailer for Ending Disease.

You can see an exclusive screening of Ending Disease on Friday, January 8th, 2021 at 5:00pm PST.

After the livestream, there will be a live Q&A session where former members of the successful Proposition 14 campaign team – which refunded CIRM with an additional $5.5 billion – will be joined by CIRM’s President and CEO Dr. Maria Millan, talking about what lies ahead for CIRM and the future of stem cell research.

To purchase a ticket, click here. It only costs $12 and 50% of the ticket sales proceeds will go to Americans for Cures to help them continue to advocate for the advancement of stem cell research, and more importantly, for the patients and families to whom stem cell research provides so much hope.

If you need any extra persuading that it’s something you should definitely put on our calendar, here’s a letter from the film maker Joe Gantz.

I am the director of the documentary Ending Disease: The Stem Cell, Anti-Cancer T-Cell, & Antibody Revolution In Medicine, a film that will help inform people about the progress that’s been made in this field and how people with their lives on the line are now able to benefit from these new regenerative therapies. 

I was granted unprecedented access to ten of the first generation of clinical trials using stem cell and regenerative medicine to treat and cure many of the most devastating diseases and conditions including: brain cancer, breast cancer, leukemia and lymphoma, HIV, repairing a broken spinal cord, retinitis pigmentosa and SCID. The results are truly inspiring.

This is personal for me.  After spending four years making this documentary, I was diagnosed with bladder cancer. Upon diagnosis, I immediately felt the same desperation as millions of families who are in search of a medical breakthrough. I understood, on a personal level, what the patients we followed in the film all knew: when you are diagnosed with a disease, there is a narrow window of time in which you can effectively seek a life-saving treatment or cure. If treatment becomes available outside of that window, then it is too late. However, Ending Disease shows that with continued support for regenerative medicine, we can create a near future in which one-time cures and highly mitigating therapies are available to patients for a whole host of diseases.

Best regards,

Joe

Repairing damaged muscles

/ Kevin McCormack / 3 Comments
Close-up of the arm of a 70-year-old male patient with a torn biceps muscle as a result of a bowling injury; Photo courtesy Science Photo Library

In the time of coronavirus an awful lot of people are not just working from home they’re also working out at home. That’s a good thing; exercise is a great way to boost the immune system, stay healthy and deal with stress. But for people used to more structured workouts at the gym it can come with a downside. Trying new routines at home that look easy on YouTube, but are harder in practice could potentially increase the risk of injury.

A new study from Japan looks at what happens when you damage a muscle. It won’t help it heal faster, but it will at least let you understand what is happening inside your body as you sit there with ice on your arm and ibuprofen in your hand.

The researchers found that when you damage a muscle, for example by trying to lift too much weight or doing too many repetitions of one exercise, the damaged muscle fibers leak substances that activate nearby “satellite” stem cells. These satellite cells then flock to the site of the injury and help repair the muscle.

The team, from Kumamoto University and Nagasaki University in Japan, named the leaking substances “Damaged myofiber-derived factors” (DMDFs) – personally I think “Substances Leaked by Injured Muscles (SLIM) would be a much cooler acronym, but that’s just me. Gaining a deeper understanding of how DMDFs work might help lead to therapies for older people who have fewer satellite muscle cells, and also for conditions like muscular dystrophy and age-related muscular fragility (sarcopenia), where the number and function of satellite cells decreases.

In an article in Science Daily, Professor Yusuke Ono, the leader of the study, says it’s possible that DMDFs play an even greater role in the body:

“In this study, we proposed a new muscle injury-regeneration model. However, the detailed molecular mechanism of how DMDFs activate satellite cells remains an unclear issue for future research. In addition to satellite cell activation, DMDF moonlighting functions are expected to be diverse. Recent studies have shown that skeletal muscle secretes various factors that affect other organs and tissues, such as the brain and fat, into the bloodstream, so it may be possible that DMDFs are involved in the linkage between injured muscle and other organs via blood circulation. We believe that further elucidation of the functions of DMDFs could clarify the pathologies of some muscle diseases and help in the development of new drugs.”

The study appears in the journal Stem Cell Reports.

Perseverance: from theory to therapy. Our story over the last year – and a half

/ Kevin McCormack / Leave a comment
Some of the stars of our Annual Report

It’s been a long time coming. Eighteen months to be precise. Which is a peculiarly long time for an Annual Report. The world is certainly a very different place today than when we started, and yet our core mission hasn’t changed at all, except to spring into action to make our own contribution to fighting the coronavirus.

This latest CIRM Annual Reportcovers 2019 through June 30, 2020. Why? Well, as you probably know we are running out of money and could be funding our last new awards by the end of this year. So, we wanted to produce as complete a picture of our achievements as we could – keeping in mind that we might not be around to produce a report next year.

Dr. Catriona Jamieson, UC San Diego physician and researcher

It’s a pretty jam-packed report. It covers everything from the 14 new clinical trials we have funded this year, including three specifically focused on COVID-19. It looks at the extraordinary researchers that we fund and the progress they have made, and the billions of additional dollars our funding has helped leverage for California. But at the heart of it, and at the heart of everything we do, are the patients. They’re the reason we are here. They are the reason we do what we do.

Byron Jenkins, former Naval fighter pilot who battled back from his own fight with multiple myeloma

There are stories of people like Byron Jenkins who almost died from multiple myeloma but is now back leading a full, active life with his family thanks to a CIRM-funded therapy with Poseida. There is Jordan Janz, a young man who once depended on taking 56 pills a day to keep his rare disease, cystinosis, under control but is now hoping a stem cell therapy developed by Dr. Stephanie Cherqui and her team at UC San Diego will make that something of the past.

Jordan Janz and Dr. Stephanie Cherqui

These individuals are remarkable on so many levels, not the least because they were willing to be among the first people ever to try these therapies. They are pioneers in every sense of the word.

Sneha Santosh, former CIRM Bridges student and now a researcher with Novo Nordisk

There is a lot of information in the report, charting the work we have done over the last 18 months. But it’s also a celebration of everyone who made it possible, and our way of saying thank you to the people of California who gave us this incredible honor and opportunity to do this work.

We hope you enjoy it.

Two rare diseases, two pieces of good news

/ Kevin McCormack / 1 Comment
Dr. Stephanie Cherqui

Last week saw a flurry of really encouraging reports from projects that CIRM has supported. We blogged about two of them last Wednesday, but here’s another two programs showing promising results.

UC San Diego researcher Dr. Stephanie Cherqui is running a CIRM-funded clinical trial for cystinosis. This is a condition where patients lack the ability to clear an amino acid called cystine from their cells. As the cystine builds up it can lead to multi-organ failure affecting the kidneys, eyes, thyroid, muscle, and pancreas.

Dr. Cherqui uses the patient’s own blood stem cells, that have been genetically corrected in the lab to remove the defective gene that causes the problem. It’s hoped these new cells will help reduce the cystine buildup.

The data presented at the annual meeting of the American Society of Cell and Gene Therapy (ASCGT) focused on the first patient treated with this approach. Six months after being treated the patient is showing positive trends in kidney function. His glomerular filtration rate (a measure of how well the kidneys are working) has risen from 38 (considered a sign of moderate to severe loss of kidney function) to 52 (mild loss of kidney function). In addition, he has not had to take the medication he previously needed to control the disorder, nor has he experienced any serious side effects from the therapy.

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Dr. Linda Marban of Capricor

Capricor Therapeutics also had some positive news about its therapy for people with Duchenne’s Muscular Dystrophy (DMD). This is a progressive genetic disorder that slowly destroys the muscles. It affects mostly boys. By their teens many are unable to walk, and most die of heart or lung failure in their 20’s. 

Capricor is using a therapy called CAP-1002, using cells derived from heart stem cells, in the HOPE-2 clinical trial.

In a news release Capricor said 12-month data from the trial showed improvements in heart function, lung function and upper body strength. In contrast, a placebo control group that didn’t get the CAP-1002 treatment saw their condition deteriorate.

Craig McDonald, M.D., the lead investigator on the study, says these results are really encouraging.  “I am incredibly pleased with the outcome of the HOPE-2 trial which demonstrated clinically relevant benefits of CAP-1002 which resulted in measurable improvements in upper limb, cardiac and respiratory function. This is the first clinical trial which shows benefit to patients in advanced stages of DMD for which treatment options are limited.”

You can read the story of Caleb Sizemore, one of the patients treated in the CIRM-funded portion of this trial.