Every so often you hear a story and your first reaction is “oh, I have to share this with someone, anyone, everyone.” That’s what happened to me the other day.
I was talking with Kristin MacDonald, an amazing woman, a fierce patient advocate and someone who took part in a CIRM-funded clinical trial to treat retinitis pigmentosa (RP). The disease had destroyed Kristin’s vision and she was hoping the therapy, pioneered by jCyte, would help her. Kristin, being a bit of a pioneer herself, was the first person to test the therapy in the U.S.
Anyway, Kristin was doing a Zoom presentation and wanted to look her best so she asked a friend to come over and do her hair and makeup. The woman she asked, was Rosie Barrero, another patient in that RP clinical trial. Not so very long ago Rosie was legally blind. Now, here she was helping do her friend’s hair and makeup. And doing it beautifully too.
That’s when you know the treatment works. At least for Rosie.
There are many other stories to be heard – from patients and patient advocates, from researchers who develop therapies to the doctors who deliver them. – at our CIRM 2020 Grantee Meeting on next Monday September 14th Tuesday & September 15th.
It’s two full days of presentations and discussions on everything from heart disease and cancer, to COVID-19, Alzheimer’s, Parkinson’s and spina bifida. Here’s a link to the Eventbrite page where you can find out more about the event and also register to be part of it.
Like pretty much everything these days it’s a virtual event so you’ll be able to join in from the comfort of your kitchen, living room, even the backyard.
And it’s free!
You can join us for all two days or just one session on one day. The choice is yours. And feel free to tell your friends or anyone else you think might be interested.
According to the Centers for Disease Control and Prevention (CDC), heart disease is the leading cause of death for men, women, and people of most racial and ethnic groups in the United States. About 647,000 Americansdie from heart disease each year, which is roughly one out of every four deaths total in the US.
In order to better study heart disease, Dr. Brenda Ogle and her team at the University of Minnesota have successfully 3D printed a functioning centimeter-scale human heart pump.
Previously, researchers have attempted to 3D print heart muscle cells within a 3D structure called an extracellular matrix. The heart muscle cells were made from induced pluripotent stem cells (iPSCs), a type of stem cell that can turn into virtually any kind of cell. Unfortunately, the cell density needed for the heart cells to function was never reached.
In this study. Dr. Ogle and her team made some slight changes to the process that had failed previously. First, they optimized a specialized ink made from extracellular matrix proteins. They then mixed the newly created ink with human iPSCs and used this new mixture to 3D print the chambered structure. The iPSCS were expanded to high cell densities in the structure first, and then were differentiated into heart muscle cells. The heart muscle model is about 1.5 centimeters long and was specifically designed to fit into the abdominal cavity of a mouse for future studies.
A video of this process can be seen below:
The team of researchers found that for the first time ever they could achieve the goal of high cell density to allow the cells to beat together, just like a human heart. Furthermore, this study shows how heart muscle cells can organize and work together. The iPSCs differentiating into heart muscle cells right next to each other is comparable to how stem cells grow in the body and then undergo specification to heart muscle cells.
A video of the heart pump contractions can be seen below as well:
In a press release from the University of Minnesota, Dr. Ogle elaborates on the implications of this study.
“We now have a model to track and trace what is happening at the cell and molecular level in pump structure that begins to approximate the human heart. We can introduce disease and damage into the model and then study the effects of medicines and other therapeutics.”
The full results of this study were published in Circulation Research.
There is still a lot that we don’t understand about SARS-CoV-2 (COVID-19), the new coronavirus that has caused a worldwide pandemic. Some patients that contract the virus experiences heart problems, but the reasons are not entirely clear. Pre-existing heart conditions or inflammation and oxygen deprivation that result from COVID-19 have all been implicated but more evidence needs to be collected.
To evaluate this, a joint study between Cedars-Sinai Board of Governors Regenerative Medicine Institute and the UCLA Broad Stem Cell Research Center used human induced pluripotent stem cells (iPSCs), a kind of stem cell that can become any kind of cell in the body and is usually made from skin cells. The iPSCS were converted into heart cells and infected with COVID-19 in order to study the effects of the virus.
The results of this study showed that the iPSC-derived heart cells are susceptible to COVID-19 infection and that the virus can quickly divide inside the heart cells. Furthermore, the infected heart cells showed changes in their ability to beat 72 hours after infection.
In a press release, Dr. Clive Svendsen, senior and co-corresponding author of the study and director of the Cedars-Sinai Board of Governors Regenerative Medicine Institute, elaborated on the results.
“This viral pandemic is predominately defined by respiratory symptoms, but there are also cardiac complications, including arrhythmias, heart failure and viral myocarditis. While this could be the result of massive inflammation in response to the virus, our data suggest that the heart could also be directly affected by the virus in COVID-19.”
Although this study does not perfectly replicate the conditions inside the human body, the iPSC heart cells may also help identify and screen new potential drugs that could alleviate viral infection of the heart.
The research team has already found that treatment with an antibody called ACE2 was able to decrease viral replication on the iPSC heart cells.
In the same press release Dr. Arun Sharma, first author and another co-corresponding author of the study and a research fellow at the Cedars-Sinai Board of Governors Regenerative Medicine Institute, had this to say about the ACE2 antibody.
“By blocking the ACE2 protein with an antibody, the virus is not as easily able to bind to the ACE2 protein, and thus cannot easily enter the cell. This not only helps us understand the mechanisms of how this virus functions, but also suggests therapeutic approaches that could be used as a potential treatment for SARS-CoV-2 infection.”
The study’s third co-corresponding author was Dr. Vaithilingaraja Arumugaswami, an associate professor of molecular and medical pharmacology at the David Geffen School of Medicine at UCLA and member of the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research.
The full results of this study were published in Cell Reports Medicine.
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.
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.”
Way back in 2013, the CIRM Board invested $32 million in a project to create an iPSC Bank. The goal was simple; to collect tissue samples from people who have different diseases, turn those samples into high quality stem cell lines – the kind known as induced pluripotent stem cells (iPSC) – and create a facility where those lines can be stored and distributed to researchers who need them.
Fast forward almost seven years and that idea has now become the largest public iPSC bank in the world. The story of how that happened is the subject of a great article (by CIRM’s Dr. Stephen Lin) in the journal Science Direct.
In 2013 there was a real need for the bank. Scientists around the world were doing important research but many were creating the cells they used for that research in different ways. That made it hard to compare one study to another and come up with any kind of consistent finding. The iPSC Bank was designed to change that by creating one source for high quality cells, collected, processed and stored under a single, consistent method.
Tissue samples – either blood or skin – were collected from thousands of individuals around California. Each donor underwent a thorough consent process – including being shown a detailed brochure – to explain what iPS cells are and how the research would be done.
The diseases to be studied through this bank include:
Age-Related Macular Degeneration (AMD)
Autism Spectrum Disorder (ASD)
Cardiomyopathies (heart conditions)
Fatty Liver diseases
Hepatitis C (HCV)
Primary Open Angle Glaucoma
The samples were screened to make sure they were safe – for example the blood was tested for HBV and HIV – and then underwent rigorous quality control testing to make sure they met the highest standards.
Once approved the samples were then turned into iPSCs at a special facility at the Buck Institute in Novato and those lines were then made available to researchers around the world, both for-profit and non-profit entities.
Scientists are now able to use these cells for a wide variety of uses including disease modeling, drug discovery, drug development, and transplant studies in animal research models. It gives them a greater ability to study how a disease develops and progresses and to help discover and test new drugs or other therapies
The Bank, which is now run by FUJIFILM Cellular Dynamics, has become a powerful resource for studying genetic variation between individuals, helping scientists understand how disease and treatment vary in a diverse population. Both CIRM and Fuji Film are committed to making even more improvements and additions to the collection in the future to ensure this is a vital resource for researchers for years to come.
On December 12th we hosted our latest ‘Facebook Live: Ask the Stem Cell Team’ event. This time around we really did mean team. We had a host of our Science Officers answering questions from friends and supporters of CIRM. We got a lot of questions and didn’t have enough time to address them all. So here’s answers to all the questions.
What are the obstacles to using partial cellular reprogramming to return people’s entire bodies to a youthful state.Paul Hartman. San Leandro, California
Dr. Kelly Shepard: Certainly, scientists have observed that various manipulations of cells, including reprogramming, partial reprogramming, de-differentiation and trans-differentiation, can restore or change properties of cells, and in some cases, these changes can reflect a more “youthful” state, such as having longer telomeres, better proliferative capacity, etc. However, some of these same rejuvenating properties, outside of their normal context, could be harmful or deadly, for example if a cell began to grow and divide when or where it shouldn’t, similar to cancer. For this reason, I believe the biggest obstacles to making this approach a reality are twofold: 1) our current, limited understanding of the nature of partially reprogrammed cells; and 2) our inability to control the fate of those cells that have been partially reprogrammed, especially if they are inside a living organism. Despite the challenges, I think there will be step wise advances where these types of approaches will be applied, starting with specific tissues. For example, CIRM has recently funded an approach that uses reprogramming to make “rejuvenated” versions of T cells for fighting lung cancer. There is also a lot of interest in using such approaches to restore the reparative capacity of aged muscle. Perhaps some successes in these more limited areas will be the basis for expanding to a broader use.
What’s going on with Stanford’s stem cell trials for stroke? I remember the first trial went really well In 2016 have not heard anything about since? Elvis Arnold
Dr. Lila Collins: Hi Elvis, this is an evolving story. I believe you are referring to SanBio’s phase 1/2a stroke trial, for which Stanford was a site. This trial looked at the safety and feasibility of SanBio’s donor or allogeneic stem cell product in chronic stroke patients who still had motor deficits from their strokes, even after completing physical therapy when natural recovery has stabilized. As you note, some of the treated subjects had promising motor recoveries.
SanBio has since completed a larger, randomized phase 2b trial in stroke, and they have released the high-level results in a press release. While the trial did not meet its primary endpoint of improving motor deficits in chronic stroke, SanBio conducted a very similar randomized trial in patients with stable motor deficits from chronic traumatic brain injury (TBI). In this trial, SanBio saw positive results on motor recovery with their product. In fact, this product is planned to move towards a conditional approval in Japan and has achieved expedited regulatory status in the US, termed RMAT, in TBI which means it could be available more quickly to patients if all goes well. SanBio plans to continue to investigate their product in stroke, so I would stay tuned as the work unfolds.
Also, since you mentioned Stanford, I should note that Dr Gary Steinberg, who was a clinical investigator in the SanBio trial you mentioned, will soon be conducting a trial with a different product that he is developing, neural progenitor cells, in chronic stroke. The therapy looks promising in preclinical models and we are hopeful it will perform well for patients in the clinic.
I am a stroke survivor will stem cell treatment able to restore my motor skills?Ruperto
Dr. Lila Collins:
Hi Ruperto. Restoring motor loss after stroke is a very active area of research. I’ll touch upon a few ongoing stem cell trials. I’d just like to please advise that you watch my colleague’s comments on stem cell clinics (these can be found towards the end of the blog) to be sure that any clinical research in which you participate is as safe as possible and regulated by FDA.
Back to stroke, I mentioned SanBio’s ongoing work to address motor skill loss in chronic stroke earlier. UK based Reneuron is also conducting a phase 2 trial, using a neural progenitor cell as a candidate therapy to help recover persistent motor disability after stroke (chronic). Dr Gary Steinberg at Stanford is also planning to conduct a clinical trial of a human embryonic stem cell-derived neuronal progenitor cell in stroke.
There is also promising work being sponsored by Athersys in acute stroke. Athersys published results from their randomized, double blinded placebo controlled Ph2 trial of their Multistem product in patients who had suffered a stroke within 24-48 hours. After intravenous delivery, the cells improved a composite measure of stroke recovery, including motor recovery. Rather than acting directly on the brain, Multistem seems to work by traveling to the spleen and reducing the inflammatory response to a stroke that can make the injury worse.
Athersys is currently recruiting a phase 3 trial of its Multistem product in acute stroke (within 1.5 days of the stroke). The trial has an accelerated FDA designation, called RMAT and a special protocol assessment. This means that if the trial is conducted as planned and it reaches the results agreed to with the FDA, the therapy could be cleared for marketing. Results from this trial should be available in about two years.
Questions from several hemorrhagic stroke survivors who say most clinical trials are for people with ischemic strokes. Could stem cells help hemorrhagic stroke patients as well?
Dr. Lila Collins:
Regarding hemorrhagic stroke, you are correct the bulk of cell therapies for stroke target ischemic stroke, perhaps because this accounts for the vast bulk of strokes, about 85%.
That said, hemorrhagic strokes are not rare and tend to be more deadly. These strokes are caused by bleeding into or around the brain which damages neurons. They can even increase pressure in the skull causing further damage. Because of this the immediate steps treating these strokes are aimed at addressing the initial bleeding insult and the blood in the brain.
While most therapies in development target ischemic stroke, successful therapies developed to repair neuronal damage or even some day replace lost neurons, could be beneficial after hemorrhagic stroke as well.
I had an Ischemic stroke in 2014, and my vision was also affected. Can stem cells possibly help with my vision issues. James Russell
Dr. Lila Collins:
Hi James. Vision loss from stroke is complex and the type of loss depends upon where the stroke occurred (in the actual eye, the optic nerve or to the other parts of the brain controlling they eye or interpreting vision). The results could be:
Visual loss from damage to the retina
You could have a normal eye with damage to the area of the brain that controls the eye’s movement
You could have damage to the part of the brain that interprets vision.
You can see that to address these various issues, we’d need different cell replacement approaches to repair the retina or the parts of the brain that were damaged.
Replacing lost neurons is an active effort that at the moment is still in the research stages. As you can imagine, this is complex because the neurons have to make just the right connections to be useful.
Is there any stem cell therapy for optical nerve damage? Deanna Rice
Dr. Ingrid Caras: There is currently no proven stem cell therapy to treat optical nerve damage, even though there are shady stem cell clinics offering treatments. However, there are some encouraging early gene therapy studies in mice using a virus called AAV to deliver growth factors that trigger regeneration of the damaged nerve. These studies suggest that it may be possible to restore at least some visual function in people blinded by optic nerve damage from glaucoma
I read an article about ReNeuron’s retinitis pigmentosa clinical trial update. In the article, it states: “The company’s treatment is a subretinal injection of human retinal progenitors — cells which have almost fully developed into photoreceptors, the light-sensing retinal cells that make vision possible.” My question is: If they can inject hRPC, why not fully developed photoreceptors?Leonard
Dr. Kelly Shepard: There is evidence from other studies, including from other tissue types such as blood, pancreas, heart and liver, that fully developed (mature) cell types tend not to engraft as well upon transplantation, that is the cells do not establish themselves and survive long term in their new environment. In contrast, it has been observed that cells in a slightly less “mature” state, such as those in the progenitor stage, are much more likely to establish themselves in a tissue, and then differentiate into more mature cell types over time. This question gets at the crux of a key issue for many new therapies, i.e. what is the best cell type to use, and the best timing to use it.
My question for the “Ask the Stem Cell Team” event is: When will jCyte publish their Phase IIb clinical trial results. Chris Allen
Dr. Ingrid Caras: The results will be available sometime in 2020.
I understand the hRPC cells are primarily neurotropic (rescue/halt cell death); however, the literature also says hRPC can become new photoreceptors. My questions are:Approximately what percentage develop into functioning photoreceptors? And what percentage of the injected hRPC are currently surviving?Leonard Furber, an RP Patient
Dr. Kelly Shepard: While we can address these questions in the lab and in animal models, until there is a clinical trial, it is not possible to truly recreate the environment and stresses that the cells will undergo once they are transplanted into a human, into the site where they are expected to survive and function. Thus, the true answer to this question may not be known until after clinical trials are performed and the results can be evaluated. Even then, it is not always possible to monitor the fate of cells after transplantation without removing tissues to analyze (which may not be feasible), or without being able to transplant labeled cells that can be readily traced.
Dr. Ingrid Caras – Although the cells have been shown to be capable of developing into photoreceptors, we don’t know if this actually happens when the cells are injected into a patient’s eye. The data so far suggest that the cells work predominantly by secreting growth factors that rescue damaged retinal cells or even reverse the damage. So one possible outcome is that the cells slow or prevent further deterioration of vision. But an additional possibility is that damaged retinal cells that are still alive but are not functioning properly may become healthy and functional again which could result in an improvement in vision.
What advances have been made using stem cells for the treatment of Type 2 Diabetes?Mary Rizzo
Dr. Ross Okamura: Type 2 Diabetes (T2D) is a disease where the body is unable to maintain normal glucose levels due to either resistance to insulin-regulated control of blood sugar or insufficient insulin production from pancreatic beta cells. The onset of disease has been associated with lifestyle influenced factors including body mass, stress, sleep apnea and physical activity, but it also appears to have a genetic component based upon its higher prevalence in certain populations.
Type 1 Diabetes (T1D) differs from T2D in that in T1D patients the pancreatic beta cells have been destroyed by the body’s immune system and the requirement for insulin therapy is absolute upon disease onset rather than gradually developing over time as in many T2D cases. Currently the only curative approach to alleviate the heavy burden of disease management in T1D has been donor pancreas or islet transplantation. However, the supply of donor tissue is small relative to the number of diabetic patients. Donor islet and pancreas transplants also require immune suppressive drugs to prevent allogenic immune rejection and the use of these drugs carry additional health concerns. However, for some patients with T1D, especially those who may develop potentially fatal hypoglycemia, immune suppression is worth the risk.
To address the issue of supply, there has been significant activity in stem cell research to produce insulin secreting beta cells from pluripotent stem cells and recent clinical data from Viacyte’s CIRM funded trial indicates that implanted allogeneic human stem cell derived cells in T1D patients can produce circulating c-peptide, a biomarker for insulin. While the trial is not designed specifically to cure insulin-dependent T2D patients, the ability to produce and successfully engraft stem cell-derived beta cells would be able to help all insulin-dependent diabetic patients.
It’s also worth noting that there is a sound scientific reason to clinically test a patient-derived pluripotent stem cell-based insulin-producing cells in insulin-dependent T2D diabetic patients; the cells in this case could be evaluated for their ability to cure diabetes in the absence of needing to prevent both allogeneic and autoimmune responses.
SPINAL CORD INJURY
Is there any news on clinical trials for spinal cord injury? Le Ly
Kevin McCormack: The clinical trial CIRM was funding, with Asterias (now part of a bigger company called Lineage Cell Therapeutics, is now completed and the results were quite encouraging. In a news release from November of 2019 Brian Culley, CEO of Lineage Cell Therapeutics, described the results this way.
“We remain extremely excited about the potential for OPC1 (the name of the therapy used) to provide enhanced motor recovery to patients with spinal cord injuries. We are not aware of any other investigative therapy for SCI (spinal cord injury) which has reported as encouraging clinical outcomes as OPC1, particularly with continued improvement beyond 1 year. Overall gains in motor function for the population assessed to date have continued, with Year 2 assessments measuring the same or higher than at Year 1. For example, 5 out of 6 Cohort 2 patients have recovered two or more motor levels on at least one side as of their Year 2 visit whereas 4 of 6 patients in this group had recovered two motor levels as of their Year 1 visit. To put these improvements into perspective, a one motor level gain means the ability to move one’s arm, which contributes to the ability to feed and clothe oneself or lift and transfer oneself from a wheelchair. These are tremendously meaningful improvements to quality of life and independence. Just as importantly, the overall safety of OPC1 has remained excellent and has been maintained 2 years following administration, as measured by MRI’s in patients who have had their Year 2 follow-up visits to date. We look forward to providing further updates on clinical data from SCiStar as patients continue to come in for their scheduled follow up visits.”
Lineage Cell Therapeutics plans to meet with the FDA in 2020 to discuss possible next steps for this therapy.
In the meantime the only other clinical trial I know that is still recruiting is one run by a company called Neuralstem. Here is a link to information about that trial on the www.clinicaltrials.gov website.
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? Angela Harrison Johnson
Dr. Ingrid Caras: The treated patients have to be followed for a period of time to assess how the therapy is working and then the data will need to be analyzed. So we will not expect to see the results probably for another year or two.
Are there treatments for autism or fragile x using stem cells? Magda Sedarous
Dr. Kelly Shepard: Autism and disorders on the autism spectrum represent a collection of many different disorders that share some common features, yet have different causes and manifestations, much of which we still do not understand. Knowing the origin of a disorder and how it affects cells and systems is the first step to developing new therapies. CIRM held a workshop on Autism in 2009 to brainstorm potential ways that stem cell research could have an impact. A major recommendation was to exploit stem cells and new technological advances to create cells and tissues, such as neurons, in the lab from autistic individuals that could then be studied in great detail. CIRM followed this recommendation and funded several early-stage awards to investigate the basis of autism, including Rett Syndrome, Fragile X, Timothy Syndrome, and other spectrum disorders. While these newer investigations have not yet led to therapies that can be tested in humans, this remains an active area of investigation. Outside of CIRM funding, we are aware of more mature studies exploring the effects of umbilical cord blood or other specific stem cell types in treating autism, such as an ongoing clinical trial conducted at Duke University.
What is happening with Parkinson’s research? Hanifa Gaphoor
Dr. Kent Fitzgerald: Parkinson’s disease certainly has a significant amount of ongoing work in the regenerative medicine and stem cell research.
The nature of cell loss in the brain, specifically the dopaminergic cells responsible for regulating the movement, has long been considered a good candidate for cell replacement therapy.
This is largely due to the hypothesis that restoring function to these cells would reverse Parkinson’s symptoms. This makes a lot of sense as front line therapy for the disease for many years has been dopamine replacement through L-dopa pills etc. Unfortunately, over time replacing dopamine through a pill loses its benefit, whereas replacing or fixing the cells themselves should be a more permanent fix.
Because a specific population of cells in one part of the brain are lost in the disease, multiple labs and clinicians have sought to replace or augment these cells by transplantation of “new” functional cells able to restore function to the area an theoretically restore voluntary motor control to patients with Parkinson’s disease.
Early clinical research showed some promise, however also yielded mixed results, using fetal tissue transplanted into the brains of Parkinson’s patients. As it turns out, the cell types required to restore movement and avoid side effects are somewhat nuanced. The field has moved away from fetal tissue and is currently pursuing the use of multiple stem cell types that are driven to what is believed to be the correct subtype of cell to repopulate the lost cells in the patient.
One project CIRM sponsored in this area with Jeanne Loring sought to develop a cell replacement therapy using stem cells from the patients themselves that have been reprogrammed into the kinds of cell damaged by Parkinson’s. This type of approach may ultimately avoid issues with the cells avoiding rejection by the immune system as can be seen with other types of transplants (i.e. liver, kidney, heart etc).
Still, others are using cutting edge gene therapy technology, like the clinical phase project CIRM is sponsoring with Krystof Bankiewicz to investigate the delivery of a gene (GDNF) to the brain that may help to restore the activity of neurons in the Parkinson’s brain that are no longer working as they should.
The bulk of the work in the field of PD at the present remains centered on replacing or restoring the dopamine producing population of cells in the brain that are affected in disease.
Any plans for Huntington’s?Nikhat Kuchiki
Dr. Lisa Kadyk: The good news is that there are now several new therapeutic approaches to Huntington’s Disease that are at various stages of preclinical and clinical development, including some that are CIRM funded. One CIRM-funded program led by Dr. Leslie Thompson at UC Irvine is developing a cell-based therapeutic that consists of neural stem cells that have been manufactured from embryonic stem cells. When these cells are injected into the brain of a mouse that has a Huntington’s Disease mutation, the cells engraft and begin to differentiate into new neurons. Improvements are seen in the behavioral and electrophysiological deficits in these mutant mice, suggesting that similar improvements might be seen in people with the disease. Currently, CIRM is funding Dr. Thompson and her team to carry out rigorous safety studies in animals using these cells, in preparation for submitting an application to the FDA to test the therapy in human patients in a clinical trial.
There are other, non-cell-based therapies also being tested in clinical trials now, using anti-sense oligonucleotides (Ionis, Takeda) to lower the expression of the Huntington protein. Another HTT-lowering approach is similar – but uses miRNAs to lower HTT levels (UniQure,Voyager)
TRAUMATIC BRAIN INJURY (TBI)
My 2.5 year old son recently suffered a hypoxic brain injury resulting in motor and speech disabilities. There are several clinical trials underway for TBI in adults. My questions are:
Will the results be scalable to pediatric use and how long do you think it would take before it is available to children?
I’m wondering why the current trials have chosen to go the route of intracranial injections as opposed to something slightly less invasive like an intrathecal injection?
Is there a time window period in which stem cells should be administered by, after which the administration is deemed not effective?
Dr. Kelly Shepard: TBI and other injuries of the nervous system are characterized by a lot of inflammation at the time of injury, which is thought to interfere with the healing process- and thus some approaches are intended to be delivered after that inflammation subsides. However, we are aware of approaches that intend to deliver a therapy to a chronic injury, or one that has occurred previously. Thus, the answer to this question may depend on how the intended therapy is supposed to work. For example, is the idea to grow new neurons, or is it to promote the survival of neurons of other cells that were spared by the injury? Is the therapy intended to address a specific symptom, such as seizures? Is the therapy intended to “fill a gap” left behind after inflammation subsides, which might not restore all function but might ameliorate certain symptoms.? There is still a lot we don’t understand about the brain and the highly sophisticated network of connections that cannot be reversed by only replacing neurons, or only reducing inflammation, etc. However, if trials are well designed, they should yield useful information even if the therapy is not as effective as hoped, and this information will pave the way to newer approaches and our technology and understanding evolves.
We have had a doctor recommending administering just the growth factors derived from MSC stem cells. Does the science work that way? Is it possible to isolate the growth factors and boost the endogenous growth factors by injecting allogenic growth factors?
Dr. Stephen Lin: Several groups have published studies on the therapeutic effects in non-human animal models of using nutrient media from MSC cultures that contain secreted factors, or extracellular vesicles from cells called exosomes that carry protein or nucleic acid factors. Scientifically it is possible to isolate the factors that are responsible for the therapeutic effect, although to date no specific factor or combination of factors have been identified to mimic the effects of the undefined mixtures in the media and exosomes. At present no regulatory approved clinical therapy has been developed using this approach.
PREDATORY STEM CELL CLINICS
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?Kathy Jean Schultz
Dr. Geoff Lomax: Terrific question! I have been doing quite a bit research into the history of this issue of unethical practitioners and I found an 1842 reference to “quack medicines.” Clearly this is nothing new. In that day, the author appealed to make society “acquainted with the facts.”
In California, we have taken steps to (1) acquaint patients with the facts about stem cell treatments and (2) advance FDA authorized treatments for unmet medical needs.
First, CIRM work with Senator Hernandez in 2017 to write a law the requires provides to disclose to patient that a stem cell therapy has not been approved by the Food and Drug administration.
We continue to work with the State Legislature and Medical Board of California to build on policies that require accurate disclosure of the facts to patients.
Second, our clinical trial network the — Alpha Stem Cell Clinics – have supported over 100 FDA-authorized clinical trials to advance responsible clinical research for unmet medical needs.
I’m curious if adipose stem cell being used at clinics at various places in the country is helpful or beneficial?Cheri Hicks
Adipose tissue has been widely used particularly in plastic and reconstructive surgery. Many practitioners suggest adipose cells are beneficial in this context. With regard to regenerative medicine and / or the ability to treat disease and injury, I am not aware of any large randomized clinical trials that demonstrate the safety and efficacy of adipose-derived stem cells used in accordance with FDA guidelines.
I went to a “Luncheon about Stem Cell Injections”. It sounded promising. I went thru with it and got the injections because I was desperate from my knee pain. The price of stem cell injections was $3500 per knee injection. All went well. I have had no complications, but haven’t noticed any real major improvement, and here I am a year later. My questions are:
1) I wonder on where the typical injection cells are coming from?
2) I wonder what is the actual cost of the cells?
3) What kind of results are people getting from all these “pop up” clinics or established clinics that are adding this to there list of offerings?
Dr. Geoff Lomax: You raise a number of questions and point here; they are all very good and it’s is hard to give a comprehensive response to each one, but here is my reaction:
There are many practitioners in the field of orthopedics who sincerely believe in the potential of cell-based treatments to treat injury / pain
Most of the evidence presented is case reports that individuals have benefited
The challenge we face is not know the exact type of injury and cell treatments used.
Well controlled clinical trials would really help us understand for what cells (or cell products) and for what injury would be helpful
Prices of $3000 to $5000 are not uncommon, and like other forms of private medicine there is often a considerable mark-up in relation to cost of goods.
You are correct that there have not been reports of serious injury for knee injections
However the effectiveness is not clear while simultaneously millions of people have been aided by knee replacements.
Do stem cells have benefits for patients going through chemotherapy and radiation therapy?Ruperto
Dr. Kelly Shepard: The idea that a stem cell therapy could help address effects of chemotherapy or radiation is being and has been pursued by several investigators over the years, including some with CIRM support. Towards the earlier stages, people are looking at the ability of different stem cell-derived neural cell preparations to replace or restore function of certain brain cells that are damaged by the effects of chemotherapy or radiation. In a completely different type of approach, a group at City of Hope is exploring whether a bone marrow transplant with specially modified stem cells can provide a protective effect against the chemotherapy that is used to treat a form of brain cancer, glioblastoma. This study is in the final stage of development that, if all goes well, culminates with application to the FDA to allow initiation of a clinical trial to test in people.
Dr. Ingrid Caras: That’s an interesting and valid question. There is a Phase 1 trial ongoing that is evaluating a novel type of stem/progenitor cell from the umbilical cord of healthy deliveries. In animal studies, these cells have been shown to reduce the toxic effects of chemotherapy and radiation and to speed up recovery. These cells are now being tested in a First-in-human clinical trial in patients who are undergoing high-dose chemotherapy to treat their disease.
There is a researcher at Stanford, Michelle Monje, who is investigating that the role of damage to stem cells in the cognitive problems that sometimes arise after chemo- and radiation therapy (“chemobrain”). It appears that damage to stem cells in the brain, especially those responsible for producing oligodendrocytes, contributes to chemobrain. In CIRM-funded work, Dr. Monje has identified small molecules that may help prevent or ameliorate the symptoms of chemobrain.
Is it possible to use a technique developed to fight one disease to also fight another? For instance, the bubble baby disease, which has cured (I think) more than 50 children, may also help fight sickle cell anemia? Don Reed.
Dr. Lisa Kadyk: Hi Don. Yes, the same general technique can often be applied to more than one disease, although it needs to be “customized” for each disease. In the example you cite, the technique is an “autologous gene-modified bone marrow transplant” – meaning the cells come from the patient themselves. This technique is relevant for single gene mutations that cause diseases of the blood (hematopoietic) system. For example, in the case of “bubble baby” diseases, a single mutation can cause failure of immune cell development, leaving the child unable to fight infections, hence the need to have them live in a sterile “bubble”. To cure that disease, blood stem cells, which normally reside in the bone marrow, are collected from the patient and then a normal version of the defective gene is introduced into the cells, where it is incorporated into the chromosomes. Then, the corrected stem cells are transplanted back into the patient’s body, where they can repopulate the blood system with cells expressing the normal copy of the gene, thus curing the disease.
A similar approach could be used to treat sickle cell disease, since it is also caused by a single gene mutation in a gene (beta hemoglobin) that is expressed in blood cells. The same technique would be used as I described for bubble baby disease but would differ in the gene that is introduced into the patient’s blood stem cells.
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? Jason
Dr. Kelly Shepard: CIRM always has and continues to believe that basic research is vital to the field of regenerative medicine. Over the past 10 years CIRM has invested $904 million in “discovery stage/basic research”, and about $215 million in training grants that supported graduate students, post docs, clinical fellows, undergraduate, masters and high school students performing basic stem cell research. In the past couple of years, with only a limited amount of funds remaining, CIRM made a decision to invest most of the remaining funds into later stage projects, to support them through the difficult transition from bench to bedside. However, even now, CIRM continues to sponsor some basic research through its Bridges and SPARK Training Grant programs, where undergraduate, masters and even high school students are conducting stem cell research in world class stem cell laboratories, many of which are the same laboratories that were supported through CIRM basic research grants over the past 10 years. While basic stem cell research continues to receive a substantial level of support from the NIH ($1.8 billion in 2018, comprehensively on stem cell projects) and other funders, CIRM believes continued support for basic research, especially in key areas of stem cell research and vital opportunities, will always be important for discovering and developing new treatments.
What is the future of the use of crispr cas9 in clinical trials in california/globally. Art Venegas
Dr. Kelly Shepard: CRISPR/Cas9 is a powerful gene editing tool. In only a few years, CRISPR/Cas9 technology has taken the field by storm and there are already a few CRISPR/Cas9 based treatments being tested in clinical trials in the US. There are also several new treatments that are at the IND enabling stage of development, which is the final testing stage required by the FDA before a clinical trial can begin. Most of these clinical trials involving CRISPR go through an “ex vivo” approach, taking cells from the patient with a disease causing gene, correcting the gene in the laboratory using CRISPR, and reintroducing the cells carrying the corrected gene back into the patient for treatment. Sickle cell disease is a prime example of a therapy being developed using this strategy and CIRM funds two projects that are preparing for clinical trials with this approach. CRISPR is also being used to develop the next generation of cancer T-cell therapies (e.g. CAR-T), where T-cells – a vital part of our immune system – are modified to target and destroy cancer cell populations. Using CRISPR to edit cells directly in patients “in vivo” (inside the body) is far less common currently but is also being developed. It is important to note that any FDA sanctioned “in vivo” CRISPR clinical trial in people will only modify organ-specific cells where the benefits cannot be passed on to subsequent generations. There is a ban on funding for what are called germ line cells, where any changes could be passed down to future generations.
CIRM is currently supporting multiple CRISPR/Cas9 gene editing projects in California from the discovery or most basic stage of research, through the later stages before applying to test the technique in people in a clinical trial.
While the field is new – if early safety signals from the pioneering trials are good, we might expect a number of new CRISPR-based approaches to enter clinical testing over the next few years. The first of these will will likely be in the areas of bone marrow transplant to correct certain blood/immune or metabolic diseases, and cancer immunotherapies, as these types of approaches are the best studied and furthest along in the pipeline.
Explain the differences between gene therapy and stem cell therapy?Renee Konkol
Dr. Stephen Lin: Gene therapy is the direct modification of cells in a patient to treat a disease. Most gene therapies use modified, harmless viruses to deliver the gene into the patient. Gene therapy has recently seen many success in the clinic, with the first FDA approved therapy for a gene induced form of blindness in 2017 and other approvals for genetic forms of smooth muscle atrophy and amyloidosis.
Stem cell therapy is the introduction of stem cells into patients to treat a disease, usually with the purpose of replacing damaged or defective cells that contribute to the disease. Stem cell therapies can be derived from pluripotent cells that have the potential to turn into any cell in the body and are directed towards a specific organ lineage for the therapy. Stem cell therapies can also be derived from other cells, called progenitors, that have the ability to turn into a limited number of other cells in the body. for example hematopoietic or blood stem cells (HSCs), which are found in bone marrow, can turn into other cells of the blood system including B-cells and T-cells: while mesenchymal stem cells (MSCs), which are usually found in fat tissue, can turn into bone, cartilage, and fat cells. The source of these cells can be from the patient’s own body (autologous) or from another person (allogeneic).
Gene therapy is often used in combination with cell therapies when cells are taken from the patient and, in the lab, modified genetically to correct the mutation or to insert a correct form of the defective gene, before being returned to patients. Often referred to as “ex vivo gene therapy” – because the changes are made outside the patient’s body – these therapies include Chimeric Antigen Receptor T (CAR-T) cells for cancer therapy and gene modified HSCs to treat blood disorders such as severe combined immunodeficiency and sickle cell disease. This is an exciting area that has significantly improved and even cured many people already.
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?James L. Sherley, M.D., Ph.D., Director. Asymmetrex, LLC
Dr. Stephen Lin: Stem cell therapies that receive approval to conduct clinical trials must submit a package of data to the FDA that includes studies that demonstrate their effectiveness, usually in animal models of the disease that the cell therapy is targeting. Those studies have data on the dose of the cell therapy that creates the therapeutic effect, which is used to estimate cell doses for the clinical trial. CIRM funds discovery and translational stage awards to conduct these types of studies to prepare cell therapies for clinical trials. The clinical trial is also often designed to test multiple doses of the cell therapy to determine the one that has the best therapeutic effect. Dosing can be very challenging with cell therapies because of issues including survival, engraftment, and immune rejection, but CIRM supports studies designed to provide data to give the best estimate possible.
Is there any research on using stem cells to increase the length of long bones in people?” For example, injecting stem cells into the growth plates to see if the cells can be used to lengthen limbs.Sajid
Dr. Kelly Shepard: There is quite a lot of ongoing research seeking ways to repair bones with stem cell based approaches, which is not the same but somewhat related. Much of this is geared towards repairing the types of bone injuries that do not heal well naturally on their own (large gaps, dead bone lesions, degenerative bone conditions). Also, a lot of this research involves engineering bone tissues in the lab and introducing the engineered tissue into a bone lesion that need be repaired. What occurs naturally at the growth plate is a complex interaction between many different cell types, much of which we do not fully understand. We do not fully understand how to use the cells that are used to engineer bone tissue in the lab. However, a group at Stanford, with some CIRM support, recently discovered a “skeletal stem cell” that exists naturally at the ends of human bones and at sites of fracture. These are quite different than MSCs and offer a new path to be explored for repairing and generating bone.
The invention of GPS navigation systems has made finding your way around so much easier, providing simple instructions on how to get from point A to point B. Now, a new study shows that our bodies have their own internal navigation system that helps stem cells know where to go, and when, in order to build a human heart. And the study also shows what can go wrong when even a few cells fail to follow directions.
In this CIRM-supported study, a team of researchers at the Gladstone Institutes in San Francisco, used a new technique called single cell RNA sequencing to study what happens in a developing heart. Single cell RNA sequencing basically takes a snapshot photo of all the gene activity in a single cell at one precise moment. Using this the researchers were able to follow the activity of tens of thousands of cells as a human heart was being formed.
“This sequencing technique allowed us
to see all the different types of cells present at various stages of heart development
and helped us identify which genes are activated and suppressed along the way. We
were not only able to uncover the existence of unknown cell types, but we also
gained a better understanding of the function and behavior of individual
cells—information we could never access before.”
Then they partnered with a team at Luxembourg Centre for Systems
Biomedicine (LCSB) of the University of Luxembourg which ran a
computational analysis to identify which genes were involved in creating
different cell types. This highlighted one specific gene, called Hand2, that controls
the activity of thousands of other genes. They found that a lack of Hand2 in
mice led to an inability to form one of the heart’s chambers, which in turn led
to impaired blood flow to the lungs. The embryo was creating the cells needed
to form the chamber, but not a critical pathway that would allow those cells to
get where they were needed when they were needed.
Gifford says this has given us a deeper insight into how
cells are formed, knowledge we didn’t have before.
“Single-cell technologies can inform us about how organs
form in ways we couldn’t understand before and can provide the underlying cause
of disease associated with genetic variations. We revealed subtle differences
in very, very small subsets of cells that actually have catastrophic
consequences and could easily have been overlooked in the past. This is the
first step toward devising new therapies.”
These therapies are needed to help treat congenital heart
defects, which are the most common and deadly birth defects. There are more
than 2.5 million Americans with these defects. Deepak Srivastava, President of
Gladstone and the leader of the study, said the knowledge gained in this study
could help developed strategies to help address that.
to see the long-term consequences in adults, and right now, we don’t really
have any way to treat them. My hope is that if we can understand the genetic
causes and the cell types affected, we could potentially intervene soon after
birth to prevent the worsening of their state over time.
Heart disease continues to be the number one cause of death in the United States. An estimated 375,000 people have a genetic form of heart disease known as familial dilated cardiomyopathy. This occurs when the heart muscle becomes weakened in one chamber in the heart, causing the open area of the chamber to become enlarged or dilated. As a result of this, the heart can no longer beat regularly, causing shortness of breath, chest pain and, in severe cases, sudden and deadly cardiac arrest.
A CIRM funded study by a team of researchers at Stanford University looked further into this form of genetic heart disease by taking a patient’s skin cells and converting them into stem cells known as induced pluripotent stem cells (iPSCs), which can become any type of cell in the body. These iPSCs were then converted into heart muscle cells that pulse just as they do in the body. These newly made heart muscle cells beat irregularly, similar to what is observed in the genetic heart condition.
Upon further analysis, the researchers linked a receptor called PGDF to cause various genes to be more highly activated in the mutated heart cells compared to normal ones. Two drugs, crenolanib and sunitinib, interfere with the PGDF receptor. After treating the abnormal heart cells, they began beating more regularly, and their gene-activation patterns more closely matched those of cells from healthy donors.
These two drugs are already FDA-approved for treating various cancers, but previous work shows that the drugs may damage the heart at high doses. The next step would be determining the right dose of the drug. The current study is part of a broader effort by the researchers to use these patient-derived cells-in-a-dish to screen for and discover new drugs.
Dr. Joseph Wu, co-senior author of this study, and his team have generated heart muscle cells from over 1,000 patients, including those of Dr. Wu, his son, and his daughter. In addition to using skin cells, the same technique to create heart cells from patients can also be done with 10 milliliters of blood — roughly two teaspoons.
“With 10 milliliters of blood, we can make clinically usable amounts of your beating heart cells in a dish…Our postdocs have taken my blood and differentiated my pluripotent stem cells into my brain cells, heart cells and liver cells. I’m asking them to test some of the medications that I might need to take in the future.”
Last week’s news headlines were dominated by one big story, the use of a stem cell transplant to effectively cure a person of HIV. But there were other stories that, while not quite as striking, did also highlight how the field is advancing.
A new way to boost brain cells
It’s hard to fix
something if you don’t really know what’s wrong in the first place. It would be
like trying to determine why a car is not working just by looking at the hood
and not looking inside at the engine. The human brain is far more complex than
a car so trying to determine what’s going wrong is infinitely more challenging.
But a new study could help give us a new option.
Luxembourg and Germany have developed a new computer model for what’s happening
inside the brain, identifying what cells are not operating properly, and fixing
Antonio del Sol, one
of the lead authors of the study – published in the journal Cell
– says their new model allows them to identify which stem cells are active and
ready to divide, or dormant.
“Our results constitute an important
step towards the implementation of stem cell-based therapies, for instance for
neurodegenerative diseases. We were able to show that, with computational
models, it is possible to identify the essential features that are
characteristic of a specific state of stem cells.”
The work, done in
mice, identified a protein that helped keep brain stem cells inactive in older
animals. By blocking this protein they were able to help “wake up” those stem
cells so they could divide and proliferate and help regenerate the aging brain.
And if it works in
mice it must work in people right? Well, that’s what they hope to see next.
Deeper understanding of fetal development
According to the Mayo
Clinic between 10 and 20 percent of known pregnancies end in
miscarriage (though they admit the real number may be even higher) and our lack
of understanding of fetal development makes it hard to understand why. A new
study reveals a previously unknown step in this development that could help
provide some answers and, hopefully, lead to ways to prevent miscarriages.
Researchers at the
Karolinska Institute in Sweden used genetic sequencing to follow the
development stages of mice embryos. By sorting those different sequences into a
kind of blueprint for what’s happening at every stage of development they were
able to identify a previously unknown phase. It’s the time between when the
embryo attaches to the uterus and when it begins to turn these embryonic stem
cells into identifiable parts of the body.
Lead researcher Qiaolin Deng says this finding provides vital new evidence.
“Being able to follow the
differentiation process of every cell is the Holy Grail of developmental
biology. Knowledge of the events and factors that govern the development of the
early embryo is indispensable for understanding miscarriages and congenital
disease. Around three in every 100 babies are born with fetal malformation
caused by faulty cellular differentiation.”
Could a new drug discovery
reduce damage from a heart attack?
Every 40 seconds someone in the US has a heart attack. For many it is fatal but even for those who survive it can lead to long-term damage to the heart that ultimately leads to heart failure. Now British researchers think they may have found a way to reduce that likelihood.
Using stem cells to
create human heart muscle tissue in the lab, they identified a protein that is
activated after a heart attack or when exposed to stress chemicals. They then
identified a drug that can block that protein and, when tested in mice that had
experienced a heart attack, they found it could reduce damage to the heart
muscle by around 60 percent.
Prof Michael Schneider,
the lead researcher on the study, published in Cell
Stem Cell, said this could be a game changer.
“There are no
existing therapies that directly address the problem of muscle cell death and
this would be a revolution in the treatment of heart attacks. One reason why
many heart drugs have failed in clinical trials may be that they have not been
tested in human cells before the clinic. Using both human cells and animals
allows us to be more confident about the molecules we take forward.”
Human heart cells generated in the laboratory. Image courtesy of Nathan Palapant at the University of Queensland
Heart disease is the leading cause of death for both men and women in the United States and is estimated to be responsible for 31% of all deaths globally. This disease encompasses a wide variety of conditions that all effect how well your heart is able to pump blood to the rest of your body. One of the reasons that heart disease is so devastating is because, unlike many other organs in our bodies, heart tissue is not able to repair itself once it is damaged. Now scientists at the Institute for Molecular Bioscience at the University of Queensland and the Garvan Institute for Medical Research in Australia have conducted a tour de force study to exquisitely understand the genes involved in heart development.
The findings of the study are published in the journal Cell Stem Cell. in a press release, Dr. Nathan Palapant, one of the the lead authors, says this type of research could pay dividends for heart disease treatment because:
“We think the answers to heart repair almost certainly lie in understanding heart development. If we can get to grips with the complex choreography of how the heart builds itself in the first place, we’re well placed to find new approaches to helping it rebuild after damage.”
To determine which genes are involved in heart cell development, the investigators use a method called single cell RNA sequencing. This technique allowed them to measure how 17,000 genes (almost every gene that is active in the heart) were being turned on and off during various stages of heart cell development in 40,000 human pluripotent stem cells (stem cells that are capable of becoming any other cell type) experimentally induced to turn into heart cells. This data set, the first of its kind, is a critical new resource for all scientists studying heart development and disease.
Interestingly, this study also addressed a commonly present, but rarely discussed issue with scientific studies: how applicable are results generated in vitro (in the lab) rather than the body, in the context of human health and disease? It is well known that heart cells generated in the lab do not have the exact same characteristics as mature heart cells found in our bodies, but the extent and precise nature of those discrepancies is not well understood. These scientists find that a gene called HOPX, which is one of earliest markers of heart cell development, is not always expressed when it should be during in vitro cardiac cell development, which, in turn, affects expression of other genes that are downstream of HOPX later on in development. Therefore, these scientists suggest that mis-expression of HOPX might be one reason why in vitro heart cells express different genes and are distinct from heart cells in humans.
The scientists also learned that HOPX is responsible for controlling whether the developing heart cell moves past the “immature” dividing phase to the mature phase where cells grow bigger, but do not divide. This finding shows that this data set is powerful both for determining differences between laboratory grown cells versus mature human cells, but also provides critical biological information about heart cell development.
Joseph Powell, another lead author of this research, further explains how this work contributes to the important fundamentals of heart cell development:
“Each cell goes through its own series of complex, nuanced changes. They are all different, and changes in one cell affect the activity of other cells. By tracking those changes across the different stages of development, we can learn a huge amount about how different sub-types of heart cells are controlled, and how they work together to build the heart.”