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

Antibody to make stem cells safer:

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

A*STAR

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

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

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

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

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

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

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

Reviving hope for Parkinson’s patients:

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

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

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

tabar-viviane

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

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

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

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

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

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

Hans runs for Congress:

Keirstead

Hans Keirstead: Photo courtesy Orange County Register

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

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

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

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

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

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

 

 

 

 

 

 

 

 

 

Latest space launch sends mice to test bone-building drug

Illustration of mice adapting to their custom-designed space habitat on board the International Space Station. Image courtesy of the Center for the Advancement of Science in Space

Astronauts on the International Space Station (ISS) received some furry guests this weekend with the launch of SpaceX’s Dragon supply capsule. On Saturday June 3rd, 40 mice were sent to the ISS along with other research experiments and medical equipment. Scientists will be treating the mice with a bone-building drug in search of a new therapy to combat osteoporosis, a disease that weakens bones and affects over 200 million people globally.

The bone-building therapy comes out of CIRM-funded research by UCLA scientists Dr. Chia Soo, Dr. Kang Ting and Dr. Ben Wu. Back in 2015, the UCLA team published that a protein called NELL-1 stimulates bone-forming stem cells, known as mesenchymal stem cells, to generate new bone tissue more efficiently in mice. They also found that NELL-1 blocked the function of osteoclasts – cellular recycling machines that break down and absorb bone – thus increasing bone density in mice.

Encouraged by their pre-clinical studies, the team decided to take their experiments into space. In collaboration with NASA and a grant from the Center for the Advancement of Science in Space (CASIS), they made plans to test NELL-1’s effects on bone density in an environment where bone loss is rapidly accelerated due to microgravity conditions.

Bone loss is a major concern for astronauts living in space for extended periods of time. The earth’s gravity puts pressure on our bones, stimulating bone-forming cells called osteoblasts to create new bone. Without gravity, osteoblasts stop functioning while the rate of bone resorption increases by approximately 1.5% per month. This translates to almost a 10% loss in bone density for every 6 months in space.

In a UCLA news release, Dr. Wu explained how they modified the NELL-1 treatment to stand up to the tests of space:

“To prepare for the space project and eventual clinical use, we chemically modified NELL-1 to stay active longer. We also engineered the NELL-1 protein with a special molecule that binds to bone, so the molecule directs NELL-1 to its correct target, similar to how a homing device directs a missile.”

The 40 mice will receive NELL-1 injections for four weeks on the ISS, at which point, half of the mice will be sent back to earth to receive another four weeks of NELL-1 treatment. The other half will stay in space and receive the same treatment so the scientists can compare the effects of NELL-1 in space and on land.

The Rodent Research Hardware System includes three modules: Habitat, Transporter, and Animal Access Unit.
Credits: NASA/Dominic Hart

The UCLA researchers hope that NELL-1 will prevent bone loss in the space mice and could lead to a new treatment for bone loss or bone injury in humans. Dr. Soo explained in an interview with SpaceFlight Now,

“We are hoping this study will give us some insights on how NELL-1 can work under these extreme conditions and if it can work for treating microgravity-related bone loss, which is a very accelerated, severe form of bone loss, then perhaps it can (be used) for patients one day on Earth who have bone loss due to trauma or due to aging or disease.”

If you want to learn more about this study, watch this short video below provided by UCLA. 

Stem cell stories that caught our eye: brains, brains and more brains!

This week we bring you three separate stories about the brain. Two are exciting new advances that use stem cells to understand the brain and the third is plain creepy.

Bioengineering better brains. Lab grown mini-brains got an upgrade thanks to a study published this week in Nature Biotechnology. Mini-brains are tiny 3D organs that harbor similar cell types and structures found in the human brain. They are made from pluripotent stem cells cultured in laboratory bioreactors that allow these cells to mature into brain tissue in the span of a month.

The brain organoid technology was first published back in 2013 by Austrian scientists Jürgen Knoblich and Madeline Lancaster. They used mini-brains to study human brain development and a model a birth defect called microcephaly, which causes abnormally small heads in babies. Mini-brains filled a void for scientists desperate for better, more relevant models of human brain development. But the technology had issues with consistency and produced organoids that varied in size, structure and cell type.

Cross-section of a mini-brain. (Madeline Lancaster/MRC-LMB)

Fast forward four years and the same team of scientists has improved upon their original method by adding a bioengineering technique that will generate more consistent mini-brains. Instead of relying on the stem cells to organize themselves into the proper structures in the brain, the team developed a biological scaffold made of microfilaments that guides the growth and development of stem cells into organoids. They called these “engineered cerebral organoids” or enCORs for short.

In a news feature on IMBA, Jürgen Knoblich explained that enCORs are more reproducible and representative of the brain’s architecture, thus making them more effective models for neurological and neurodevelopmental disorders.

“An important hallmark of the bioengineered organoids is their increased surface to volume ratio. Because of their improved tissue architecture, enCORs can allow for the study of a broader array of neurological diseases where neuronal positioning is thought to be affected, including lissencephaly (smooth brain), epilepsy, and even autism and schizophrenia.”

Salk team finds genetic links between brain’s immune cells and neurological disorders. (Todd Dubnicoff)

Dysfunction of brain cells called microglia have been implicated in a wide range of neurologic disorders like Alzheimer’s, Parkinson’s, Huntington’s, autism and schizophrenia. But a detailed examination of these cells has proved difficult because they don’t grow well in lab dishes. And attempts to grow microglia from stem cells is hampered by the fact that the cell type hasn’t been characterized enough for researchers to know how to distinguish it from related cell types found in the blood.

By performing an extensive analysis of microglia gene activity, Salk Institute scientists have now pinpointed genetic links between these cells and neurological disease. These discoveries also demonstrate the importance of the microglia’s environment within the brain to maintain its identity. The study results were reported in Science.

Microglia are important immune cells in the brain. They are related to macrophages which are white blood cells that roam through the body via the circulatory system and gobble up damaged or dying cells as well as foreign invaders. Microglia also perform those duties in the brain and use their eating function to trim away faulty or damage nerve connections.

To study a direct source of microglia, the team worked with neurosurgeons to obtain small samples of brain tissue from patients undergoing surgery for epilepsy, a tumor or stroke. Microglia were isolated from healthy regions of brain tissue that were incidentally removed along with damaged or diseased brain tissue.

Salk and UC San Diego scientists conducted a vast survey of microglia (pictured here), revealing links to neurodegenerative diseases and psychiatric illnesses. (Image: Nicole Coufal)

A portion of the isolated microglia were immediately processed to take a snap shot of gene activity. The researchers found that hundreds of genes in the microglia had much higher activities compared to those same genes in macrophages. But when the microglia were transferred to petri dishes, gene activity in general dropped. In fact, within six hours of tissue collection, the activity of over 2000 genes in the cells had dropped significantly. This result suggests the microglial rely on signals in the brain to stimulate their gene activity and may explain why they don’t grow well once removed from that environment into lab dishes.

Of the hundreds of genes whose activity were boosted in microglia, the researchers tracked down several that were linked to several neurological disorders. Dr. Nicole Coufal summarized these results and their implications in a Salk press release:

“A really high proportion of genes linked to multiple sclerosis, Parkinson’s and schizophrenia are much more highly expressed in microglia than the rest of the brain. That suggests there’s some kind of link between microglia and the diseases.”

Future studies are needed to explain the exact nature of this link. But with these molecular descriptions of microglia gene activity now in hand, the researchers are in a better position to study microglia’s role in disease.

A stem cell trial to bring back the dead, brain-dead that is. A somewhat creepy stem cell story resurfaced in the news this week. A company called Bioquark in Philadelphia is attempting to bring brain-dead patients back to life by injecting adult stem cells into their spinal cords in combination with other treatments that include protein blend injections, electrical nerve stimulation and laser therapy. The hope is that this combination stem cell therapy will generate new neurons that can reestablish lost connections in the brain and bring it back to life.

Abstract image of a neuron. (Dom Smith/STAT)

You might wonder why the company is trying multiple different treatments simultaneously. In a conversation with STAT news, Bioquark CEO Ira Pastor explained,

“It’s our contention that there’s no single magic bullet for this, so to start with a single magic bullet makes no sense. Hence why we have to take a different approach.”

Bioquark is planning to relaunch a clinical trial testing its combination therapy in Latin America sometime this year. The company previously attempted to launch its first trial in India back in April of 2016, but it never got off the ground because it failed to get clearance from India’s Drug Controller General.

STATnews staff writer Kate Sheridan called the trial “controversial” and raised questions about how it would impact patients and their families.

“How do researchers complete trial paperwork when the person participating is, legally, dead? If the person did regain brain activity, what kind of functional abilities would he or she have? Are families getting their hopes up for an incredibly long-shot cure?”

Scientists also have questions mainly about whether this treatment will actually work or is just a shot in the dark. Adding to the uncertainty is the fact that Bioquark has no preclinical evidence that its combination treatment is effective in animal models. The STAT piece details how the treatments have been tested individually for other conditions such as stroke and coma, but not in brain-dead patients. To further complicate things, there is no consensus on how to define brain death in patients, so patient improvements observed during the trial could be unrelated to the treatment.

STAT asked expert doctors in the field whether Bioquark’s strategy was feasible. Orthopedic surgeon Dr. Ed Cooper said that there’s no way electric stimulation would work, pointing out that the technique requires a functioning brain stem which brain-dead patients don’t have. Pediatric surgeon Dr. Charles Cox, who works on a stem cell treatment for traumatic brain injury and is unrelated to Bioquark, commented, “it’s not the absolute craziest thing I’ve ever heard, but I think the probability of that working is next to zero.”

But Pastor seems immune to the skepticism and naysayers.

“I give us a pretty good chance. I just think it’s a matter of putting it all together and getting the right people and the right minds on it.”

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

smoking mom

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

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

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

Dangerous cocktail

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

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

Long term damage

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

The study is published in the Archives of Toxicology.

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

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

Stem cell stories that caught our eye: lab-grown blood stem cells and puffer fish have the same teeth stem cells as humans

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Scientists finally grow blood stem cells in the lab!

Two exciting stem cell studies broke through the politics-dominated headlines this week. Both studies, published in the journal Nature, demonstrated that human hematopoietic or blood stem cells can be grown in the lab.

This news is a big deal because scientists have yet to make bonafide blood stem cells from pluripotent stem cells or other human cells. These stem cells not only create all the cells in our blood and immune systems, but also can be used to develop therapies for patients with blood cancers and genetic blood disorders.

But to do these experiments, you need a substantial source of blood stem cells – something that has eluded scientists for decades. That’s where these two studies come to the rescue. One study was spearheaded by George Daley at the Boston Children’s Hospital in Massachusetts and the other was led by Shahin Rafii at the Weill Cornell Medical College in New York City.

Researchers have made blood stem cells and progenitor cells from pluripotent stem cells. Credit: Steve Gschmeissner Getty Images

George Daley and his team developed a strategy that matured human induced pluripotent stem cells (iPS cells) into blood-forming stem and progenitor cells. It’s a two-step process that first uses a cocktail of chemicals to make hemogenic endothelium, the embryonic tissue that generates blood stem cells. The second step involved treating these intermediate cells with a combination of seven transcription factors that directed them towards a blood stem cell fate.

These modified human blood stem cells were then transplanted into mice where they developed into blood stem cells that produced blood and immune cells. First author on the study, Ryohichi Sugimura, explained the applications that their technology could be used for in a Boston Children’s Hospital news release,

“This step opens up an opportunity to take cells from patients with genetic blood disorders, use gene editing to correct their genetic defect and make functional blood cells. This also gives us the potential to have a limitless supply of blood stem cells and blood by taking cells from universal donors. This could potentially augment the blood supply for patients who need transfusions.”

The second study by Shahin Rafii and his team at Cornell used a different strategy to generate blood-forming stem cells. Instead of genetically manipulating iPS cells, they selected a more mature cell type to directly reprogram into blood stem cells. Using four transcription factors, they successfully reprogrammed mouse endothelial cells, which line the insides of blood vessels, into blood-forming stem cells that repopulated the blood and immune systems of irradiated mice.

Raffii believe his method is simpler and more efficient than Daley’s. In coverage by Nature News, he commented,

“Using the most efficient method to generate stem cells matters because every time a gene is added to a batch of cells, a large portion of the batch fails to incorporate it and must be thrown out. There is also a risk that some cells will mutate after they are modified in the lab, and could form tumors if they are implanted into people.”

To play devil’s advocate, Daley’s technique might appeal more to some because the starting source of iPS cells is much easier to obtain and culture in the lab than endothelial cells that have to be extracted from the blood vessels of animals or people. Furthermore, Daley argued that his team’s method could “be made more efficient, and [is] less likely to spur tumor growth and other abnormalities in modified cells.”

The Nature News article compares the achievements of both studies and concluded,

“Time will determine which approach succeeds. But the latest advances have buoyed the spirits of researchers who have been frustrated by their inability to generate blood stem cells from iPS cells.”

 

Humans and puffer fish have the same tooth-making stem cells.

Here’s a fun fact for your next blind date: humans and puffer fish share the same genes that are responsible for making teeth. Scientists from the University of Sheffield in England discovered that the stem cells that make teeth in puffer fish are the same stem cells that make the pearly whites in humans. Their work was published in the journal PNAS earlier this week.

Puffer fish. Photo by pingpogz on Flickr.

But if you look at this puffer fish, you’ll see a dramatic difference between its smile and ours – their teeth look more like a beak. Research has shown that the tooth-forming stem cells in puffer fish produce tooth plates that form a beak-like structure, which helps them crush and consume their prey.

So why is this shared evolution between humans and puffer fish important when our teeth look and function so differently? The scientists behind this research believe that studying the pufferfish could unearth answers about tooth loss in humans. The lead author on the study, Dr. Gareth Fraser, concluded in coverage by Phys.org,

“Our study questioned how pufferfish make a beak and now we’ve discovered the stem cells responsible and the genes that govern this process of continuous regeneration. These are also involved in general vertebrate tooth regeneration, including in humans. The fact that all vertebrates regenerate their teeth in the same way with a set of conserved stem cells means that we can use these studies in more obscure fishes to provide clues to how we can address questions of tooth loss in humans.”

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

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

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

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

Taking a closer look

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

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

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

Positively encouraging

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

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

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

We can’t wait to see what they find.

Kidney Disease: There’s an Organ-on-a-Chip for That

“There’s an app for that” is a well-known phrase trademarked by Apple to promote how users can do almost anything they do on a computer on their mobile phone. Apps are so deeply ingrained in everyday life that it’s hard for some people to imagine living without them. (I know I’d be lost without google maps or my Next Bus app!)

An estimated 2.2 million mobile apps exist for iPhones. Imagine if this multitude of apps were instead the number of stem cell models available for scientists to study human biology and disease. Scientists dream of the day when they can respond to questions about any disease and say, “there’s a model for that.” However, a future where every individual or disease has its own personalized stem cell line is still far away.

In the meantime, scientists are continuing to generate stem cell-based technologies that answer important questions about how our tissues and organs function and what happens when they are affected by disease. One strategy involves growing human stem cells on microchips and developing them into miniature organ systems that function like the organs in our bodies.

Kidney-on-a-chip

A group of scientists from Harvard’s Wyss Institute are using organ-on-a-chip technology to model a structure in the human kidney, called a glomerulus, that’s essential for filtering the body’s blood. It’s made up of a meshwork of blood vessels called capillaries that remove waste, toxic products, and excess fluid from the blood by depositing them into the urine.

The glomerulus also contains cells called podocytes that wrap around the capillaries and leave thin slits for blood to filter through. Diseases that affect podocytes or the glomerulus structure can cause kidney failure early or later in life, which is why the Harvard team was so interested to model this structure using their microchip technology.

They developed a method to mature human pluripotent stem cells into podocytes by engineering an environment similar to that of a real kidney on a microchip. Using a combination of kidney-specific factors and extracellular matrix molecules, which form a supportive environment for cells within tissues and organs, the team generated mature podocytes from human stem cells in three weeks. Their study was published in Nature Biomedical Engineering and was led by Dr. Donald Ingber, Founding Director of the Wyss Institute.

3D rendering of the glomerulus-on-a-chip derived from human stem cells. (Wyss Institute at Harvard University)

First author, Samaira Musah, explained how their glomerulus-on-a-chip works in a news release,

“Our method not only uses soluble factors that guide kidney development in the embryo, but, by growing and differentiating stem cells on extracellular matrix components that are also contained in the membrane separating the glomerular blood and urinary systems, we more closely mimic the natural environment in which podocytes are induced and mature. We even succeeded in inducing much of this differentiation process within a channel of the microfluidic chip, where by applying cyclical motions that mimic the rhythmic deformations living glomeruli experience due to pressure pulses generated by each heartbeat, we achieve even greater maturation efficiencies.”

Over 90% of stem cells successfully developed into functional podocytes that could properly filter blood by selectively filtering different blood proteins. The podocytes also were susceptible to a chemotherapy drug called doxorubicin, proving that they are suitable for modeling the effects of drug toxicity on kidneys.

Kidney podocyte derived from human stem cells. (Wyss Institute)

Ingber highlighted the potential applications of their glomerulus-on-a-chip technology,

Donald Ingber, Wyss Institute

“The development of a functional human kidney glomerulus chip opens up an entire new experimental path to investigate kidney biology, carry out highly personalized modeling of kidney diseases and drug toxicities, and the stem cell-derived kidney podocytes we developed could even offer a new injectable cell therapy approach for regenerative medicine in patients with life-threatening glomerulopathies in the future.”

There’s an organ-on-a-chip for that!

The Wyss Institute team has developed other organ-on-chips including lungs, intestine, skin and bone marrow. These miniature human systems are powerful tools that scientists hope will “revolutionize drug development, disease modeling and personalized medicine” by reducing the cost of research and the reliance on animal models according to the Wyss Institute technology website.

What started out as a microengineering experiment in Ingber’s lab a few years ago is now transforming into a technology “that is now poised to have a major impact on society” Ingber further explained. If organs-on-chips live up to these expectations, you might one day hear a scientist say, “Don’t worry, there’s an organ-on-a-chip for that!”


Related Links:

A call to put the ‘public’ back in publication, and make stem cell research findings available to everyone

Opening the door

Opening the door to scientific knowledge

Thomas Gray probably wasn’t thinking about stem cell research when, in 1750 in his poem “Elegy in a Country Churchyard”, he wrote: “Full many a flower is born to blush unseen”. But a new study says that’s precisely what seems to happen to the findings of many stem cell clinical trials. They take place, but no details of their findings are ever made public. They blush, if they blush at all, unseen.

The study, in the journal Stem Cell Reports, says that only around 45 percent of stem cell clinical trials ever have their results published in peer-reviewed journals. Which means the results of around 55 percent of stem cell clinical trials are never shared with either the public or the scientific community.

Now, this finding apparently is not confined to stem cell research. Previous studies have shown a similar lack of publication of the results of more conventional therapies. Nonetheless, it’s a little disappointing – to say the least – to find out that so much knowledge and potentially valuable data is being lost due to lack of publication.

Definitely not full disclosure

Researchers at the University of Alberta in Canada used the US National Institute of Health’s (NIH) clinicaltrials.gov website as their starting point. They identified 1,052 stem cell clinical trials on the site. Only 393 trials were completed and of these, just 179 (45.4 percent) published their findings in a peer-reviewed journal.

In an interview in The Scientist, Tania Bubela, the lead researcher, says they chose to focus on stem cell clinical trials because of extensive media interest and the high public expectations for the field:

“When you have a field that is accused of over promising in some areas, it is beholden of the researchers in that field to publish the results of their trials so that the public and policy makers can realistically estimate the potential benefits.”

Now, it could be argued that publishing in a peer-reviewed journal is a rather high bar, that many researchers may have submitted articles but were rejected. However, there are other avenues for researchers to publish their findings, such as posting results on the clinicaltrials.gov database. Only 37 teams (3.5 percent) did that.

Why do it?

In the same article in The Scientist, Leigh Turner, a bioethicist at the University of Minnesota, raises the obvious question:

“The study shows a gap between studies that have taken place and actual publication of the data, so a substantial number of trials testing cell-based interventions are not entering the public domain. The underlying question is, what is the ethical and scientific basis to exposing human research subjects to risk if there is not going to be any meaningful contribution to knowledge at the end of the process?”

In short, why do it if you are not going to let anyone know what you did and what you found?

It’s a particularly relevant question when you consider that much of this research was supported with taxpayer dollars from the NIH and other institutions. So, if the public is paying for this research, doesn’t the public have a right to know what was learned?

Right to know

At CIRM we certainly think so. We expect and encourage all the researchers we fund to publish their findings. There are numerous ways and places to do that. For example, we expect each grantee to post a lay summary of their progress which we publish on our website. Stanford’s Dr. Joseph Wu’s progress reports for his work on heart disease shows you what those look like.

We also require researchers conducting clinical trials that we are funding to submit and post their trial results on the clinicaltrials.gov website.

The International Society for Stem Cell Research (ISSCR), agrees and recently updated its Guidelines for Stem Cell Research and Clinical Translation calling on researchers to publish, as fully as possible, their clinical trial results.

That is true regardless of whether or not the clinical trial showed it was both safe and effective, or whether it showed it was unsafe and ineffective. We can learn as much from failure as we can from success. But to do that we need to know what the results are.

Publishing only positive findings skews the scientific literature, and public perception of this work. Ignoring the negative could mean that other scientists waste a lot of time and money trying to do something that has already demonstrated it won’t work.

Publication should be a requirement for all research, particularly publicly funded research. It’s time to put the word “public” back in publication.

 

 

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

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

New theory for how the nervous system develops.

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

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

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

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

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

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

A UCLA press release explained what the scientists discovered next,

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

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

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

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

Age could be written in our stem cells.

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

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

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

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

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

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

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

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

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

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

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

Identical twins not so identical (Todd Dubnicoff)

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

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

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

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

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

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

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

jCyte starts second phase of stem cell clinical trial targeting vision loss

retinitis pigmentosas_1

How retinitis pigmentosa destroys vision

Studies show that Americans fear losing their vision more than any other sense, such as hearing or speech, and almost as much as they fear cancer, Alzheimer’s and HIV/AIDS. That’s not too surprising. Our eyes are our connection to the world around us. Sever that connection, and the world is a very different place.

For people with retinitis pigmentosa (RP), the leading cause of inherited blindness in the world, that connection is slowly destroyed over many years. The disease eats away at the cells in the eye that sense light, so the world of people with RP steadily becomes darker and darker, until the light goes out completely. It often strikes people in their teens, and many are blind by the time they are 40.

There are no treatments. No cures. At least not yet. But now there is a glimmer of hope as a new clinical trial using stem cells – and funded by CIRM – gets underway.

klassenWe have talked about this project before. It’s run by UC Irvine’s Dr. Henry Klassen and his team at jCyte. In the first phase of their clinical trial they tested their treatment on a small group of patients with RP, to try and ensure that their approach was safe. It was. But it was a lot more than that. For people like Rosie Barrero, the treatment seems to have helped restore some of their vision. You can hear Rosie talk about that in our recent video.

Now the same treatment that helped Rosie, is going to be tested in a much larger group of people, as jCyte starts recruiting 70 patients for this new study.

In a news release announcing the start of the Phase 2 trial, Henry Klassen said this was an exciting moment:

“We are encouraged by the therapy’s excellent safety track record in early trials and hope to build on those results. Right now, there are no effective treatments for retinitis pigmentosa. People must find ways to adapt to their vision loss. With CIRM’s support, we hope to change that.”

The treatment involves using retinal progenitor cells, the kind destroyed by the disease. These are injected into the back of the eye where they release factors which the researchers hope will help rescue some of the diseased cells and regenerate some replacement ones.

Paul Bresge, CEO of jCyte, says one of the lovely things about this approach, is its simplicity:

“Because no surgery is required, the therapy can be easily administered. The entire procedure takes minutes.”

Not everyone will get the retinal progenitor cells, at least not to begin with. One group of patients will get an injection of the cells into their worst-sighted eye. The other group will get a sham injection with no cells. This will allow researchers to compare the two groups and determine if any improvements in vision are due to the treatment or a placebo effect.

The good news is that after one year of follow-up, the group that got the sham injection will also be able to get an injection of the real cells, so that if the therapy is effective they too may be able to benefit from it.

Rosie BarreroWhen we talked to Rosie Barrero about the impact the treatment had on her, she said it was like watching the world slowly come into focus after years of not being able to see anything.

“My dream was to see my kids. I always saw them with my heart, but now I can see them with my eyes. Seeing their faces, it’s truly a miracle.”

We are hoping this Phase 2 clinical trial gives others a chance to experience similar miracles.


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