There are many unknown elements for what triggers the cells in an embryo to start dividing and multiplying and becoming every single cell in the body. Now researchers at the Gladstone Institutes in San Francisco have uncovered one of those elements, how embryos determine which cells become the head and which the tail.
In this CIRM-funded study the Gladstone team, led by Dr. Todd McDevitt, discovered almost by chance how the cells align in a heads-to-tail arrangement.
They had created an organoid made from brain cells when they noticed that some of the cells were beginning to gather in an elongated fashion, in the same way that spinal cords do in a developing fetus.
In a news article, Nick Elder, a graduate student at Gladstone and the co-author of the study, published in the journal Development, says this was not what they had anticipated would happen: “Organoids don’t typically have head-tail directionality, and we didn’t originally set out to create an elongating organoid, so the fact that we saw this at all was very surprising.”
Further study enabled the team to identify which molecules were involved in signaling specific genes to switch on and off. These were similar to the process previously identified in developing mouse embryos.
“This is such a critical point in the early development of any organism, so having a new model to observe it and study it in the lab is very exciting,” says McDevitt.
This is not just of academic interest either, it could have real world implications in helping understand what causes miscarriages or birth defects.
“We can use this organoid to get at unresolved human developmental questions in a way that doesn’t involve human embryos,” says Dr. Ashley Libby, another member of the team. “For instance, you could add chemicals or toxins that a pregnant woman might be exposed to, and see how they affect the development of the spinal cord.”
A search on Google using the term “stem cell blogs” quickly produces a host of sites offering treatments for everything from ankle, hip and knee problems, to Parkinson’s disease and asthma. Amazingly the therapies for those very different conditions all use the same kind of cells produced in the same way. It’s like magic. Sadly, it’s magic that is less hocus pocus and more bogus bogus.
The good news is there are blogs out there (besides us, of course) that do offer good, accurate, reliable information about stem cells. The people behind them are not in this to make a quick buck selling snake oil. They are in this to educate, inform, engage and enlighten people about what stem cells can, and cannot do.
This blog has just undergone a face lift and is now as colorful and easy to read as it is informative. It bills itself as the longest running stem cell blog around. It’s run by UC Davis stem cell biologist Dr. Paul Knoepfler – full disclosure, we have funded some of Paul’s work – and it’s a constant source of amazement to me how Paul manages to run a busy research lab and post regular updates on his blog.
The power of The Niche is that it’s easy for non-science folk – like me – to read and understand without having to do a deep dive into Google search or Wikipedia. It’s well written, informative and often very witty. If you are looking for a good website to check whether some news about stem cells is real or suspect, this is a great place to start.
This site is run by another old friend of CIRM’s, Don Reed. Don has written extensively about stem cell research in general, and CIRM in particular. His motivation to do this work is clear. Don says he’s not a doctor or scientist, he’s something much simpler:
“No. I am just a father fighting for his paralyzed son, and the only way to fix him is to advance cures for everyone. Also, my mother died of breast cancer, my sister from leukemia, and I myself am a prostate cancer survivor. So, I have some very personal reasons to support the California Institute for Regenerative Medicine and to want state funding for stem cell and other regenerative medicine research to continue in California!”
The power of Don’s writing is that he always tells human stories, real tales about real people. He makes everything he does accessible, memorable and often very funny. If I’m looking for ways to explain something complex and translate it into everyday English, I’ll often look at Don’s work, he knows how to talk to people about the science without having their eyes cloud over.
This is published by the International Society for Stem Cell Research (ISSCR), the leading professional organization for stem cell scientists. You might expect a blog from such a science-focused organization to be heavy going for the ordinary person, but you’d be wrong.
A Closer Look at Stem Cells is specifically designed for people who want to learn more about stem cells but don’t have the time to get a PhD. They have sections explaining what stem cells are, what they can and can’t do, even a glossary explaining different terms used in the field (I used to think the Islets of Langerhans were small islands off the coast of Germany till I went to this site).
One of the best, and most important, parts of the site is the section on clinical trials, helping people understand what’s involved in these trials and the kinds of things you need to consider before signing up for one.
Of course, the US doesn’t have a monopoly on stem cell research and that’s reflected in the next two choices. One is the Signals Blog from our friends to the north in Canada. This is an easy-to-read site that describes itself as the “Insiders perspective on the world of stem cells and regenerative medicine.” The ‘Categories ‘dropdown menu allows you to choose what you want to read, and it gives you lots of options from the latest news to a special section for patients, even a section on ethical and legal issues.
As you may have guessed from the title this is by our chums across the pond in Europe. They lay out their mission on page one saying they want to help people make sense of stem cells:
“As a network of scientists and academics, we provide independent, expert-reviewed information and road-tested educational resources on stem cells and their impact on society. We also work with people affected by conditions, educators, regulators, media, healthcare professionals and policymakers to foster engagement and develop material that meets their needs.”
True to their word they have great information on the latest research, broken down by different types of disease, different types of stem cell etc. And like CIRM they also have some great educational resources for teachers to use in the classroom.
On March 19th we held a special Facebook Live “Ask the Stem Cell Team About Autism” event. We were fortunate enough to have two great experts – Dr. Alysson Muotri from UC San Diego, and CIRM’s own Dr. Kelly Shepard. As always there is a lot of ground to cover in under one hour and there are inevitably questions we didn’t get a chance to respond to. So, Dr. Shepard has kindly agreed to provide answers to all the key questions we got on the day.
If you didn’t get a chance to see the event you can watch the video here. And feel free to share the link, and this blog, with anyone you think might be interested in the material.
Can umbilical cord blood stem cells help reduce some of the symptoms?
This question was addressed by Dr. Muotri in the live presentation. To recap, a couple of clinical studies have been reported from scientists at Duke University and Sutter Health, but the results are not universally viewed as conclusive. The Duke study, which focused on very young children, reported some improvements in behavior for some of the children after treatment, but it is important to note that this trial had no placebo control, so it is not clear that those patients would not have improved on their own. The Duke team has moved forward with larger trial and placebo control.
Does it have to be the child’s own cord blood or could donated blood work too?
In theory, a donated cord product could be used for similar purposes as a child’s own cord, but there is a caveat- the donated cord tissues must have some level of immune matching with the host in order to not be rejected or lead to other complications, which under certain circumstances, could be serious.
Some clinics claim that the use of fetal stem cells can help stimulate improved blood and oxygen flow to the brain. Could that help children with autism?
Fetal stem cells have been tested in FDA approved/sanctioned clinical trials for certain brain conditions such as stroke and Parkinson Disease, where there is clearer understanding of how and which parts of the brains are affected, which nerve cells have been lost or damaged, and where there is a compelling biological rationale for how certain properties the transplanted cells, such as their anti-inflammatory properties, could provide benefit.
In his presentation, Dr. Muotri noted that neurons are not lost in autistic brains, so there is nothing that would be “replaced” by such a treatment. And although some forms of autism might include inflammation that could potentially be mitigated, it is unlikely that the degree of benefit that might come from reducing inflammation would be worth the risks of the treatment, which includes intracranial injection of donated material. Unfortunately, we still do not know enough about the specific causes and features of autism to determine if and to what extent stem cell treatments could prove helpful. But we are learning more every day, especially with some of the new technologies and discoveries that have been enabled by stem cell technology.
Some therapies even use tissue from sheep claiming that a pill containing sheep pancreas can migrate to and cure a human pancreas, pills containing sheep brains can help heal human brains. What are your thoughts on those?
For some conditions, there may be a scientific rationale for how a specific drug or treatment could be delivered orally, but this really depends on the underlying biology of the condition, the means by which the drug exerts its effect, and how quickly that drug or substance will be digested, metabolized, or cleared from the body’s circulation. Many drugs that are delivered orally do not reach the brain because of the blood-brain barrier, which serves to isolate and protect the brain from potentially harmful substances in the blood circulation. For such a drug to be effective, it would have to be stable within the body for a period of time, and be something that could exert its effects on the brain either directly or indirectly.
Sheep brain or pancreas (or any other animal tissue consumed) in a pill form would be broken down into basic components immediately by digestion, i.e. amino acids, sugars, much like any other meat or food. Often complex treatments designed to be specifically targeted to the brain are delivered by intra-cranial/intrathecal injection, or by developing special strategies to evade the blood brain barrier, a challenge that is easier said than done. For autism, there is still a lot to be learned regarding how a therapeutic intervention might work to help people, so for now, I would caution against the use of dietary supplements or pills that are not prescribed or recommended by your doctor.
What are the questions parents should ask before signing up for any stem cell therapy
By Kelly Shepard, PhD., CIRM’s Associate Director, Discovery & Translation
CIRM has previously blogged about advances in treating certain forms of “bubble baby” disease”, where a person is born with a defect in their blood forming stem cells that results in a deficient immune system, rendering them vulnerable to lethal infections by all manner of bacteria, virus or germ.
If a suitable donor can be found, or if the patient’s own defective cells can be corrected through gene therapy approaches, it is now possible to treat or cure such disorders through a bone marrow transplant. In this procedure, healthy blood stem cells are infused into the patient, taking up residence in his or her bone marrow and dividing to give rise to functioning immune cells such as T cells and B cells.
Unfortunately, there is another type of “bubble baby” disease that cannot be treated by providing healthy blood stem cells, because the defective immune system is caused by a different culprit altogether- a missing or dysfunctional thymus.
T Cells Go to School
What is a thymus? Most of us give little thought to this leaf-shaped organ, which is large and important in our early childhoods, but becomes small and inconspicuous as we age. This transformation belies the critical role a thymus plays in the development of our adaptive immune systems, which takes place in our youth: to prepare our bodies to fight infections for the rest of our lives.
One might think of the thymus as a “school”, where immature T cells go to “learn” how to recognize and attack foreign antigens (surface markers), such as those found on microorganisms or tissues from other individuals. The thymus also “teaches” our immune system to distinguish “self” from “other” by eliminating any T cells that attack our own tissues. Without this critical function, our immune system could inadvertently turn against us, causing serious autoimmune disorders such as ulcerative colitis and myasthenia gravis.
Many children with a severely deficient or absent thymus, referred to as athymia, have inherited a chromosome that is missing a key stretch of genes on a region called 22q11. Doctors believe perhaps 1/2000-1/4000 babies are born with some type of deletion in this region, which leads to a variable spectrum of disorders called 22q11 syndrome that can affect just about any part of the body, and can even cause learning disabilities and mental illness.
Individuals with one form of 22q11, called DiGeorge Syndrome, are particularly affected in the heart, thymus, and parathyroid glands. In the United States, about 20 infants are born per year with the “complete” and most severe form of DiGeorge Syndrome, who lack a thymus altogether, and have severely depressed numbers of T cells for fighting infections. Without medical intervention, this condition is usually fatal by 24 months of age.
Optimism and Setback
Although there are no therapies approved by the Food and Drug Administration (FDA) for pediatric athymia, Dr. Mary Louise Markert at Duke University and Enzyvant, Inc. have been pioneering an experimental approach to treat children with complete DiGeorge syndrome.
In this procedure, discarded thymic tissues are collected from infants undergoing cardiac surgery, where some of the thymus needs to be removed in order for the surgeon to gain access to the heart. These tissues are processed to remove potentially harmful donor T cells and then transplanted into the thigh of an athymic DiGeorge patient.
Results from early clinical trials seemed promising, with more than 70% of patients surviving, including several who are now ten years post-transplant. Based on those results, in June of 2019 Enzyvant applied to the FDA for a Biologics License Application (BLA), which is needed to be able to sell the therapy in the US. Unfortunately, only a few months later, Enzyvant announced that the FDA had declined to approve the BLA due to manufacturing concerns.
While it may be possible to address these issues in time, the need to step back to the drawing board was a devastating blow to the DiGeorge Community, who have waited decades for a promising treatment to emerge on the horizon.
Despite the setback, there is reason to hope. In early 2019, CIRM granted a “Quest” Award to team of investigators at Stanford University to develop a novel stem cell based approach for treating thymic deficiency. Co-led by Katja Weinacht, a pediatric hematologist/oncologist, and Vittorio Sebastiano, a stem cell expert and developmental biologist, the team’s strategy is to coax induced pluripotent stem cells (iPS) in the laboratory to differentiate into thymic tissue, which could then be transplanted into patients using the route pioneered by Duke and Enzyvant.
The beauty of this new approach is that pluripotent stem cells are essentially immortal in culture, providing an inexhaustible supply of fresh thymic cells for transplant, thereby allowing greater control over the quality and consistency of donor tissues. A second major advantage is the possibility of using pluripotent cells from the patient him/herself as the source, which should be perfectly immune-matched and alleviate the risk of rejection and autoimmunity that comes with use of donated tissues.
Sounds easy, so what are the challenges? As with many regenerative medicine approaches, the key is getting a pluripotent stem cell to differentiate into the right type of cells in the lab, which is a very different environment than what cells experience naturally when they develop in the context of an embryo and womb, where many cells are interacting and providing complex, instructive cues to one another. The precise factors and timing all need to be worked out and in most cases, this is done with an incomplete knowledge of human development.
A second challenge relates to using cells from DiGeorge patients to produce thymic tissue, which are missing several genes on their 22nd chromosome and will likely require sophisticated genetic engineering to restore this ability.
Fortunately, Drs. Weinacht and Sebastiano are up to the challenge, and have already made progress in differentiating human induced pluripotent stem cells (iPS) into thymic lineage intermediates that appear to be expressing the right proteins at the right time. They plan to combine these cells with engineered materials to create a three-dimensional (3D) tissue that more closely resembles an authentic organ, and which can be tested for functionality in athymic mice.
There is more work to be done, but these advances, along with continued technological improvements and renewed efforts from Enzyvant, could forge a path to the clinic and lead to a brighter future for patients suffering from congenital athymia and other forms of thymic dysfunction.
Several weeks ago, we asked all of you to submit questions related to stem cell research in order to get them answered by experts in the field right here in our office.
Your responses have been remarkable and we have gotten some really great questions we are excited to answer in live time. These questions ranged from the impact stem cell research has had on various disease areas to differentiating legitimate clinical trials from sham treatments being offered by predatory stem cell clinics.
For those of you that might have missed the previous announcement, this is all happening in a special Facebook Live “Ask the Stem Cell Team” event on Thursday, December 12th from 10.30am to 11.30amPDT. Just tune in to our Facebook page at that date and time listed for a live video streaming!
We will do our best to answer all the questions that were submitted to us. Additionally, for those who did not get a chance to email us, you can also submit questions in the comments section of the Facebook live event in real time. If we do not get to your question, don’t worry! We will answer it in a blog at a later date.
As a preview of this event, we wanted to showcase some of the questions submitted to us that will be answered in live time. You’ll have to wait until next week to get the answers so be sure to tune in!
1. What are the obstacles to using partial cellular reprogramming to return people’s entire bodies to a youthful state?
2. What’s going on with Stanford’s stem cell trials for stroke?
3. I am a stroke survivor; will stem cell treatment able to restore my motor skills?
4. Could stem cells help hemorrhagic stroke patients as well?
5. Can stem cells possibly help with my vision issues?
6. Is there any stem cell therapy for optical nerve damage?
7. When will jCyte publish their Phase IIb clinical trial results?
8. What advances have been made using stem cells for the treatment of Type 2 Diabetes?
9. Is there any news on clinical trials for spinal cord injury?
10. Now that the Brainstorm ALS trial is finished looking for new patients, do you have any idea how it’s going and when can we expect to see results?
11. Are there treatments for Autism or Fragile X Syndrome using stem cells?
12. What is happening with Parkinson’s research?
13. Any plans for Huntington’s?
14. What practical measures are being taken to address unethical practitioners whose bad surgeries are giving stem cell advances a bad reputation and are making forward research difficult?
15. I’m curious if adipose stem cell being used at clinics at various places in the country is helpful or beneficial?
16. Do stem cells have benefits for patients going through chemotherapy and radiation therapy?
17. Is it possible to use a technique developed to fight one disease to also fight another?
18. Is there any concern that CIRM’s lack of support in basic research will hamper the amount of new approaches that can reach clinical stages?
19. What is the future of the use of CRISPR/Cas9 in clinical trials in California and globally?
20. Explain the differences between gene therapy and stem cell therapy?
21. Currently, how can the outcome of CIRM stem cell medicine projects and clinical trials be soundly interpreted when their stem cell-specific doses are not known?
22. Is there any research on using stem cells to increase the length of long bones in people?
Blood stem cells are a vital part of us. They create all the other kinds of blood cells in our body and are used in bone marrow transplants to help people battling leukemia or other blood cancers. The problem is growing these blood stem cells outside the body has always proved challenging. Up till now.
Researchers at UCLA, with CIRM funding, have identified a protein that seems to play a key role in helping blood stem cells renew themselves in the lab. Why is this important? Because being able to create a big supply of these cells could help researchers develop new approaches to treating a wide array of life-threatening diseases.
One of the most important elements that a stem cell has is its ability to self-renew itself over long periods of time. The problem with blood stem cells has been that when they are removed from the body they quickly lose their ability to self-renew and die off.
To discover why this is the case the team at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA analyzed blood stem cells to see which genes turn on and off as those cells turn into other kinds of blood cells – red, white and platelets. They identified one gene, called MLLT3, which seemed to play a key role in helping blood stem cells self-renew.
To test this finding, the researchers took blood stem cells and, in the lab, inserted copies of the MLLT3 gene into them. The modified cells were then able to self-renew at least 12 times; a number far greater than in the past.
Dr. Hanna Mikkola, a senior author of the study says this finding could help advance the field:
“If we think about the amount of blood stem cells needed to treat a patient, that’s a significant number. But we’re not just focusing on quantity; we also need to ensure that the lab-created blood stem cells can continue to function properly by making all blood cell types when transplanted.”
Happily, that seemed to be the case. When they subjected the MLLT3-enhanced blood stem cells to further analysis they found that they appeared to self-renew at a safe rate and didn’t multiply too much or mutate in ways that could lead to leukemia or other blood cancers.
The next steps are to find more efficient and effective ways of keeping the MLLT3 gene active in blood stem cells, so they can develop ways of using this finding in a clinical setting with patients.
Their findings are published in the journal Nature.
It’s never easy to tell someone that they are too late, that they missed the deadline. It’s particularly hard when you know that the person you are telling that to has spent years working on a project and now needs money to take it to the next level. But in science, as in life, it’s always better to tell people what they need to know rather than what they would like to hear.
And so, we have posted
a notice on our website for researchers thinking about applying for funding
that, except in a very few cases, they are too late, that there is no money
available for new projects, whether it’s Discovery, Translational or Clinical.
Here’s that notice:
that the budget allocation of funds for new awards under the CIRM clinical
program (CLIN1, CLIN2 and CLIN3) may be depleted within the next two to three
months. CIRM will accept applications for the monthly deadline on June 28, 2019
but will suspend application submissions after that date until further notice.
All applicants should note that the review of submitted applications may be
halted at any point in the process if funds are depleted prior to completion of
the 3-month review cycle. CIRM will notify applicants of such an occurrence.
Therefore, submission and acceptance of an application to CIRM does not
guarantee the availability of funds or completion of a review cycle.
of applications for the CIRM/NHLBI Cure Sickle Cell Initiative (CLIN1 SCD,
CLIN2 SCD) are unaffected and application submissions for this program will
We do, of course, have enough money set aside to continue
funding all the projects our Board has already approved, but we don’t have
money for new projects (except for some sickle cell disease projects).
In truth our funding has lasted a lot longer than anyone
anticipated. When Proposition 71 was approved the plan was to give CIRM $300
million a year for ten years. That was back in 2004. So what happened?
Well, in the early years stem cell science was still very
much in its infancy with most of the work being done at a basic or Discovery
level. Those typically don’t require very large sums so we were able to fund
many projects without hitting our $300m target. As the field progressed,
however, more and more projects were at the clinical trial stage and those need
multiple millions of dollars to be completed. So, the money went out faster.
To date we have funded 55 clinical trials and our
early support has helped more than a dozen other projects get into clinical
trials. This includes everything from cancer and stroke, to vision loss and
diabetes. It’s a good start, but we feel there is so much more to do.
Followers of news about CIRM know there is talk about a possible ballot initiative next year that would provide another $5.5 billion in funding for us to help complete the mission we have started.
Over the years we have built a pipeline of promising
projects and without continued support many of those projects face a difficult
future. Funding at the federal level is under threat and without CIRM there
will be a limited number of funding alternatives for them to turn to.
Telling researchers we don’t have any money to support their
work is hard. Telling patients we don’t have any money to support work that
could lead to new treatments for them, that’s hardest of all.
At first glance, a scientific conference is not the place you would think about going to learn about how to run a political or any other kind of campaign. But then the ISSCR Annual Meeting is not your average conference. And that’s why CIRM is there and has been going to these events for as long as we have been around.
For those who don’t know, ISSCR is the International Society
for Stem Cell Research. It’s the global industry representative for the field
of stem cell research. It’s where all the leading figures in the field get
together every year to chart the progress in research.
But it’s more than just the science that gets discussed. One of the panels kicking off this year’s conference was on ‘Why is it Important to Communicate with Policy Makers, the Media and the Public?” It was a wide-ranging discussion on the importance of learning the best ways for the scientific community to explain what it is they do, why they do it, and why people should care.
Morrison, a former President of ISSCR, talked about his experience
trying to pass a bill in Michigan that would enable scientists to do embryonic
stem cell research. At the time CIRM was spending millions of dollars funding
scientists in California to create new lines of embryonic stem cells; in
Michigan anyone doing the same could be sent to prison for a year. He said the
opposition ran a fear-based campaign, lying about the impact the bill would
have, that it would enable scientists to create half man-half cow creatures
(no, really) or human clones. Learning to counter those without descending to
their level was challenging, but ultimately Morrison was successful in
overcoming opposition and getting the bill passed.
Temple, of the Neural Stem Cell Institute, talked about testifying
to a Congressional committee about the importance of fetal tissue research and
faced a barrage of hostile questions that misrepresented the science and
distorted her views. In contrast Republicans on the committee had invited a group
that opposed all fetal tissue research and fed them a bunch of softball
questions; the answers the group gave not only had no scientific validity, they
were just plain wrong. Fortunately, Temple says she had done a lot of
preparation (including watching two hours Congressional hearings on C-SPAN to understand how these hearings
worked) and had her answers ready. Even so she said one of the big lessons she
stressed is the need to listen to what others are saying and respond in ways
that address their fears and don’t just dismiss them.
Other presenters talked about their struggles with different
issues and different audiences but similar experiences; how do you communicate
clearly and effectively. The answer is actually pretty simple. You talk to
people in a way they understand with language they understand. Not with dense
scientific jargon. Not with reams of data. Just by telling simple stories that
illustrate what you did and who it helped or might help.
The power of ISSCR is that it can bring together a roomful
of brilliant scientists from all over the world who want to learn about these
things, who want to be better communicators. They know that much of the money
for scientific research comes from governments or state agencies, that this is
public money, and that if the public is going to continue to support this
research it needs to know how that money is being spent.
That’s a message CIRM has been promoting for years. We know
that communicating with the public is not an option, it’s a responsibility.
That’s why, at a time when the very notion of science sometimes seems to be
under attack, and the idea of public funding for that science is certainly
under threat, having meetings like this that brings researchers together and
gives them access to new tools is vital. The tools they can “get” at ISSCR are
ones they might never learn in the lab, but they are tools that might just mean
they get the money needed to do the work they want to.
Today the governing Board of the California Institute for
Regenerative Medicine (CIRM) approved a grant of almost $12 million to Dr.
Stephanie Cherqui at the University of California, San Diego (UCSD) to conduct
a clinical trial for treatment of cystinosis.
award brings the total number of CIRM funded clinical trials to 55.
a rare disease that primarily affects children and young adults, and leads to
premature death, usually in early adulthood. Patients inherit
defective copies of a gene called CTNS, which results in abnormal accumulation
of an amino acid called cystine in all cells of the body. This buildup of cystine can lead to
multi-organ failure, with some of earliest and most pronounced effects on the
kidneys, eyes, thyroid, muscle, and pancreas.
Many patients suffer end-stage kidney failure and severe vision defects
in childhood, and as they get older, they are at increased risk for heart
disease, diabetes, bone defects, and neuromuscular defects. There is currently a drug treatment for
cystinosis, but it only delays the progression of the disease, has severe side
effects and is expensive.
Dr. Cherqui’s clinical trial will use a gene therapy
approach to modify a patient’s own blood stem cells with a functional version
of the defective CTNS gene. Based on pre-clinical
data, the approach is to reintroduce the corrected stem cells into the patient
to give rise to blood cells that will reduce cystine buildup in affected
Because this is the first time this approach has been tested in patients, the primary goal of the clinical trial is to see if the treatment is safe. In addition, patients will be monitored for improvements in the symptoms of their disease. This award is in collaboration with the University of California, Los Angeles which will handle the manufacturing of the therapy.
CIRM has also funded the preclinical work
for this study, which involved completing the testing needed to apply to the
Food and Drug Administration (FDA) for permission to start a clinical trial in
“CIRM has funded 24 clinical stage programs utilizing
cell and gene medicine approaches to date,” says Maria T. Millan, M.D., the
President and CEO of CIRM. “This project
continues to broaden the scope of unmet medical need we can impact with these
types of approaches.”
A transplant can be a lifesaving procedure for many people across the United States. In fact, according to the Health Resources & Services Administration, 36,528 transplants were performed in 2018. However, as of January 2019, the number of men, women, and children on the national transplant waiting list is over 113,000, with 20 people dying each day waiting for a transplant and a new person being added to the list every 10 minutes.
Before considering a transplant, there needs to be an immunological match between the donated tissue and/or blood stem cells and the recipient. To put it simply, a “match” indicates that the donor’s cells will not be marked by the recipient’s immune cells as foreign and begin to attack it, a process known as graft-versus-host disease. Unfortunately, these matches can be challenging to find, particularly for some ethnic minorities. Often times, immunosuppression drugs are also needed in order to prevent the foreign cells from being attacked by the body’s immune system. Additionally, chemotherapy and radiation are often needed as well.
Fortunately, a CIRM-funded study at Stanford has shown some promising results towards addressing the issue of matching donor cells and recipient. Dr. Irv Weissman and his colleagues at Stanford have found a way to prepare mice for a transplant of blood stem cells, even when donor and recipient are an immunological mismatch. Their method involved using a combination of six specific antibodies and does not require ongoing immunosuppression.
The combination of antibodies did this by eliminating several types of immune cells in the animals’ bone marrow, which allowed blood stem cells to engraft and begin producing blood and immune cells without the need for continued immunosuppression. The blood stem cells used were haploidentical, which, to put it simply, is what naturally occurs between parent and child, or between about half of all siblings.
Additional experiments also showed that the mice treated with the six antibodies could also accept completely mismatched purified blood stem cells, such as those that might be obtained from an embryonic stem cell line.
The results established in this mouse model could one day lay the foundation necessary to utilize this approach in humans after conducting clinical trials. The idea would be that a patient that needs a transplanted organ could first undergo a safe, gentle transplant with blood stem cells derived in the laboratory from embryonic stem cells. The same embryonic stem cells could also then be used to generate an organ that would be fully accepted by the recipient without requiring the need for long-term treatment with drugs to suppress the immune system.
“With support by the California Institute for Regenerative Medicine, we’ve been able to make important advances in human embryonic stem cell research. In the past, these stem cell transplants have required a complete match to avoid rejection and reduce the chance of graft-versus-host disease. But in a family with four siblings the odds of having a sibling who matches the patient this closely are only one in four. Now we’ve shown in mice that a ‘half match,’ which occurs between parents and children or in two of every four siblings, works without the need for radiation, chemotherapy or ongoing immunosuppression. This may open up the possibility of transplant for nearly everyone who needs it. Additionally, the immune tolerance we’re able to induce should in the future allow the co-transplantation of [blood] stem cells and tissues, such as insulin-producing cells or even organs generated from the same embryonic stem cell line.”
The full results to this study were published in Cell Stem Cell.