Stem Cell Stories That Caught Our Eye: Plasticity in the pancreas and two cool stem cell tools added to the research toolbox

There’s more plasticity in the pancreas than we thought. You’re taught a lot of things about the world when you’re young. As you get older, you realize that not everything you’re told holds true and it’s your own responsibility to determine fact from fiction. This evolution in understanding happens in science too. Scientists do research that leads them to believe that biological processes happen a certain way, only to sometimes find, a few years later, that things are different or not exactly what they had originally thought.

There’s a great example of this in a study published this week in Cell Metabolism about the pancreas. Scientists from UC Davis found that the pancreas, which secretes a hormone called insulin that helps regulate the levels of sugar in your blood, has more “plasticity” than was originally believed. In this case, plasticity refers to the ability of a tissue or organ to regenerate itself by replacing lost or damaged cells.

The long-standing belief in this field was that the insulin producing cells, called beta cells, are replenished when beta cells actively divide to create more copies of themselves. In patients with type 1 diabetes, these cells are specifically targeted and killed off by the immune system. As a result, the beta cell population is dramatically reduced, and patients have to go on life-long insulin treatment.

UC Davis researchers have identified another type of insulin-producing cell in the islets, which appears to be an immature beta cell shown in red. (UC Davis)

But it turns out there is another cell type in the pancreas that is capable of making beta cells and they look like a teenage, less mature version of beta cells. The UC Davis team identified these cells in mice and in samples of human pancreas tissue. These cells hangout at the edges of structures called islets, which are clusters of beta cells within the pancreas. Upon further inspection, the scientists found that these immature beta cells can secrete insulin but cannot detect blood glucose like mature beta cells. They also found their point of origin: the immature beta cells developed from another type of pancreatic cell called the alpha cell.

Diagram of immature beta cells from Cell Metabolism.

In coverage by EurekAlert, Dr Andrew Rakeman, the director of discovery research at the Juvenile Diabetes Research Foundation, commented on the importance of this study’s findings and how it could be translated into a new approach for treating type 1 diabetes patients:

“The concept of harnessing the plasticity in the islet to regenerate beta cells has emerged as an intriguing possibility in recent years. The work from Dr. Huising and his team is showing us not only the degree of plasticity in islet cells, but the paths these cells take when changing identity. Adding to that the observations that the same processes appear to be occurring in human islets raises the possibility that these mechanistic insights may be able to be turned into therapeutic approaches for treating diabetes.”

 

Say hello to iPSCORE, new and improved tools for stem cell research. Stem cells are powerful tools to model human disease and their power got a significant boost this week from a new study published in Stem Cell Reports, led by scientists at UC San Diego School of Medicine.

The team developed a collection of over 200 induced pluripotent stem cell (iPS cell) lines derived from people of diverse ethnic backgrounds. They call this stem cell tool kit “iPSCORE”, which stands for iPSC Collection for Omic Research (omics refers to a field of study in biology ending in -omics, such as genomics or proteomics). The goal of iPSCORE is to identify particular genetic variants (unique differences in DNA sequence between people’s genomes) that are associated with specific diseases and to understand why they cause disease at the molecular level.

In an interview with Phys.org, lead scientist on the study, Dr. Kelly Frazer, further explained the power of iPSCORE:

“The iPSCORE collection contains 75 lines from people of non-European ancestry, including East Asian, South Asian, African American, Mexican American, and Multiracial. It includes multigenerational families and monozygotic twins. This collection will enable us to study how genetic variation influences traits, both at a molecular and physiological level, in appropriate human cell types, such as heart muscle cells. It will help researchers investigate not only common but also rare, and even family-specific variations.”

This research is a great example of scientists identifying a limitation in stem cell research and expanding the stem cell tool kit to model diseases in a diverse human population.

A false color scanning electron micrograph of cultured human neuron from induced pluripotent stem cell. Credit: Mark Ellisman and Thomas Deerinck, UC San Diego.

Stem cells that can grow into ANY type of tissue. Embryonic stem cells can develop into any cell type in the body, earning them the classification of pluripotent. But there is one type of tissue that embryonic stem cells can’t make and it’s called extra-embryonic tissue. This tissue forms the supportive tissue like the placenta that allows an embryo to develop into a healthy baby in the womb.

Stem cells that can develop into both extra-embryonic and embryonic tissue are called totipotent, and they are extremely hard to isolate and study in the lab because scientists lack the methods to maintain them in their totipotent state. Having the ability to study these special stem cells will allow scientists to answer questions about early embryonic development and fertility issues in women.

Reporting this week in the journal Cell, scientists from the Salk Institute in San Diego and Peking University in China identified a cocktail of chemicals that can stabilize human stem cells in a totipotent state where they can give rise to either tissue type. They called these more primitive stem cells extended pluripotent stem cells or EPS cells.

Salk Professor Juan Carlos Izpisua Bemonte, co–senior author of the paper, explained the problem their study addressed and the solution it revealed in a Salk news release:

“During embryonic development, both the fertilized egg and its initial cells are considered totipotent, as they can give rise to all embryonic and extra-embryonic lineages. However, the capture of stem cells with such developmental potential in vitro has been a major challenge in stem cell biology. This is the first study reporting the derivation of a stable stem cell type that shows totipotent-like bi-developmental potential towards both embryonic and extra-embryonic lineages.”

Human EPS cells (green) can be detected in both the embryonic part (left) and extra-embryonic parts (placenta and yolk sac, right) of a mouse embryo. (Salk Institute)

Using this new method, the scientists discovered that human EPS stem cells were able to develop chimeric embryos with mouse stem cells more easily than regular embryonic stem cells. First author on the study, Jun Wu, explained why this ability is important:

“The superior chimeric competency of both human and mouse EPS cells is advantageous in applications such as the generation of transgenic animal models and the production of replacement organs. We are now testing to see whether human EPS cells are more efficient in chimeric contribution to pigs, whose organ size and physiology are closer to humans.”

The Salk team reported on advancements in generating interspecies chimeras earlier this year. In one study, they were able to grow rat organs – including the pancreas, heart and eyes – in a mouse. In another study, they grew human tissue in early-stage pig and cattle embryos with the goal of eventually developing ways to generate transplantable organs for humans. You can read more about their research in this Salk news release.

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Stem cells stories that caught our eye: switching cell ID to treat diabetes, AI predicts cell fate, stem cell ALS therapy for Canada

Treating diabetes by changing a cell’s identity. Stem cells are an ideal therapy strategy for treating type 1 diabetes. That’s because the disease is caused by the loss of a very specific cell type: the insulin-producing beta cell in the pancreas. So, several groups are developing treatments that aim to replace the lost cells by transplanting stem cell-derived beta cells grown in the lab. In fact, Viacyte is applying this approach in an ongoing CIRM-funded clinical trial.

In preliminary animal studies published late last week, a Stanford research team has shown another approach may be possible which generates beta cells inside the body instead of relying on cells grown in a petri dish. The CIRM-funded Cell Metabolism report focused on alpha cells, another cell type in pancreas which produces the hormone glucagon.

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Microscopy of islet cells, round clusters of cells found in the pancreas. The brown stained cells are glucagon-producing alpha cells. Credit: Wikimedia Commons

After eating a meal, insulin is critical for getting blood sugar into your cells for their energy needs. But glucagon is needed to release stored up sugar, or glucose, into your blood when you haven’t eaten for a while. The research team, blocked two genes in mice that are critical for maintaining an alpha cell state. Seven weeks after inhibiting the activity of these genes, the researchers saw that many alpha cells had converted to beta cells, a process called direct reprogramming.

Does the same thing happen in humans? A study of cadaver donors who had been recently diagnosed with diabetes before their death suggests the answer is yes. An analysis of pancreatic tissue samples showed cells that produced both insulin and glucagon, and appeared to be in the process of converting from beta to alpha cells. Further genetic tests showed that diabetes donor cells had lost activity in the two genes that were blocked in the mouse studies.

It turns out that there’s naturally an excess of alpha cells so, as team lead Seung Kim mentioned in a press release, this strategy could pan out:

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Seung Kim. Credit: Steve Fisch, Stanford University

“This indicates that it might be possible to use targeted methods to block these genes or the signals controlling them in the pancreatic islets of people with diabetes to enhance the proportion of alpha cells that convert into beta cells.”

Using computers to predict cell fate. Deep learning is a cutting-edge area of computer science that uses computer algorithms to perform tasks that border on artificial intelligence. From beating humans in a game of Go to self-driving car technology, deep learning has an exciting range of applications. Now, scientists at Helmholtz Zentrum München in Germany have used deep learning to predict the fate of cells.

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Using deep learning, computers can predict the fate of these blood stem cells.
Credit: Helmholtz Zentrum München.

The study, published this week in Nature Methods, focused on blood stem cells also called hematopoietic stem cells. These cells live in the bone marrow and give rise to all the different types of blood cells. This process can go awry and lead to deadly disorders like leukemia, so scientists are very interested in exquisitely understanding each step that a blood stem cell takes as it specializes into different cell types.

Researchers can figure out the fate of a blood stem cells by adding tags, which glow with various color, to the cell surface . Under a microscope these colors reveal the cells identity. But this method is always after the fact. There no way to look at a cell and predict what type of cell it is turning into. In this study, the team filmed the cells under a microscope as they transformed into different cell types. The deep learning algorithm processed the patterns in the cells and developed cell fate predictions. Now, compared to the typical method using the glowing tags, the researchers knew the eventual cell fates much sooner. The team lead, Carsten Marr, explained how this new technology could help their research:

“Since we now know which cells will develop in which way, we can isolate them earlier than before and examine how they differ at a molecular level. We want to use this information to understand how the choices are made for particular developmental traits.”

Stem cell therapy for ALS seeking approval in Canada. (Karen Ring) Amyotrophic lateral sclerosis (ALS) is a progressive neuromuscular disease that kills off the nerve cells responsible for controlling muscle movement. Patients with ALS suffer from muscle weakness, difficulty in speaking, and eventually breathing. There is no cure for ALS and the average life expectancy after diagnosis is just 2 – 5 years. But companies are pursuing stem cell-based therapies in clinical trials as promising treatment options.

One company in particular, BrainStorm Cell Therapeutics based in the US and Israel, is testing a mesenchymal stem cell-based therapy called NurOwn in ALS patients in clinical trials. In their Phase 2 trials, they observed clinical improvements in slowing down the rate of disease progression following the stem cell treatment.

In a recent update from our friends at the Signals Blog, BrainStorm has announced that it is seeking regulatory approval of its NurOwn treatment for ALS patients in Canada. They will be working with the Centre for Commercialization of Regenerative Medicine (CCRM) to apply for a special regulatory approval pathway with Health Canada, the Canadian government department responsible for national public health.

In a press release, BrainStorm CEO Chaim Lebovits, highlighted this new partnership and his company’s mission to gain regulatory approval for their ALS treatment:

“We are pleased to partner with CCRM as we continue our efforts to develop and make NurOwn available commercially to patients with ALS as quickly as possible. We look forward to discussing with Health Canada staff the results of our ALS clinical program to date, which we believe shows compelling evidence of safety and efficacy and may qualify for rapid review under Canada’s regulatory guidelines for drugs to treat serious or life-threatening conditions.”

Stacey Johnson who wrote the Signals Blog piece on this story explained that while BrainStorm is not starting a clinical trial for ALS in Canada, there will be significant benefits if its treatment is approved.

“If BrainStorm qualifies for this pathway and its market authorization request is successful, it is possible that NurOwn could be available for patients in Canada by early 2018.  True access to improved treatments for Canadian ALS patients would be a great outcome and something we are all hoping for.”

CIRM is also funding stem cell-based therapies in clinical trials for ALS. Just yesterday our Board awarded Cedars-Sinai $6.15 million dollars to conduct a Phase 1 trial for ALS patients that will use “cells called astrocytes that have been specially re-engineered to secrete proteins that can help repair and replace the cells damaged by the disease.” You can read more about this new trial in our latest news release.

Throwback Thursday: Progress to a Cure for Type 1 Diabetes

Welcome back to our “Throwback Thursday” series on the Stem Cellar. Over the years, we’ve accumulated an arsenal of valuable stem cell stories on our blog. Some of these stories represent crucial advances towards stem cell-based cures for serious diseases and deserve a second look.

novemberawarenessmonthThis week in honor of Diabetes Awareness Month, we are featuring type 1 diabetes (T1D), a chronic disease that destroys the insulin-producing beta cells in your pancreas. Without these important cells, patients cannot maintain the proper levels of glucose, a fancy name for sugar, in their blood and are at risk for many complications including heart disease, blindness, and even death.

Cell replacement therapy is evolving into an attractive option for patients with T1D. Replacing lost beta cells in the pancreas is a more permanent and less burdensome solution than the daily insulin shots (or insulin pumps) that many T1D patients currently take.

So let’s take a look at the past year’s advances in stem cell research for diabetes.

Making Insulin-Producing Cells from Stem Cells and Skin

This year, there were a lot of exciting studies that improved upon previous methods for generating pancreatic beta cells in a dish. Here’s a brief recap of a few of the studies we covered on our blog:

  • Make pancreatic cells from stem cells. Scientists from the Washington University School of Medicine in St. Louis and the Harvard Stem Cell Institute developed a method that makes beta cells from T1D patient-derived induced pluripotent stem cells (iPSCs) that behave very similarly to true beta cells both in a dish and when transplanted into diabetic mice. Their discovery has the potential to offer personalized stem cell treatments for patients with T1D in the near future and the authors of the study predicted that their technology could be ready to test in humans in the next three to five years.
  • Making functional pancreatic cells from skin. Scientists from the Gladstone Institutes used a technique called direct reprogramming to turn human skin cells directly into pancreatic beta cells without having to go all the way back to a pluripotent stem cell state. The pancreatic cells looked and acted like the real thing in a dish (they were able to secrete insulin when exposed to glucose), and they functioned normally when transplanted into diabetic mice. This study is exciting because it offers a new and more efficient method to make functioning human beta cells in mass quantities.

    Functioning human pancreatic cells after they’ve been transplanted into a mouse. (Image: Saiyong Zhu, Gladstone)

    Functioning human pancreatic cells after they’ve been transplanted into a mouse. (Image: Saiyong Zhu, Gladstone)

  • Challenges of stem cell-derived diabetes treatments. At this year’s Ogawa-Yamanaka Stem Cell Award ceremony Douglas Melton, a well-renowned diabetes researcher from Harvard, spoke about the main challenges for developing stem cell-derived diabetes treatments. The first is the need for better control over the methods that make beta cells from stem cells. The second was finding ways to make large quantities of beta cells for human transplantation. The last was finding ways to prevent a patient’s immune system from rejecting transplanted beta cells. Melton and other scientists are already working on improving techniques to make more beta cells from stem cells. As for preventing transplanted beta cells from being attacked by the patient’s immune system, Melton described two possibilities: using an encapsulation device or biological protection to mask the transplanted cells from an attack.

Progress to a Cure: Clinical Trials for Type 1 Diabetes

Speaking of encapsulation devices, CIRM is funding a Phase I clinical trial sponsored by a San Diego-based company called ViaCyte that’s hoping to develop a stem cell-based cure for patients with T1D. The treatment involves placing a small encapsulated device containing stem cell-derived pancreatic precursor cells under the skin of T1D patients. Once implanted, these precursor cells should develop into pancreatic beta cells that can secrete insulin into the patient’s blood stream. The goal of this trial is first to make sure the treatment is safe for patients and second to see if it’s effective in improving a patient’s ability to regulate their blood sugar levels.

To learn more about this exciting clinical trial, watch this fun video made by Youreka Science.

ViaCyte is still waiting on results for their Phase 1 clinical trial, but in the meantime, they are developing a modified version of their original device for T1D called PEC-Direct. This device also contains pancreatic precursor cells but it’s been designed in a way that allows the patient’s blood vessels to make direct connections to the cells inside the device. This vascularization process hopefully will improve the survival and function of the insulin producing beta cells inside the device. This study, which is in the last stage of research before clinical trials, is also being funded by CIRM, and we are excited to hear news about its progress next year.

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

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


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From Pig Parts to Stem Cells: Scientist Douglas Melton Wins Ogawa-Yamanaka Prize for Work on Diabetes

Since the 1920s, insulin injections have remained the best solution for managing type 1 diabetes. Patients with this disease do not make enough insulin – a hormone that regulates the sugar levels in your blood – because the insulin-producing cells, or beta cells, in their pancreas are destroyed.

Back then, it took two tons of pig parts to make eight ounces of insulin, which was enough to treat 10,000 diabetic patients for six months. Biotech and pharmaceutical companies have since developed different types of human insulin treatments that include fast and long acting versions of the hormone. It’s estimated that $22 billion will be spent on developing insulin products for patients this year and that costs will rise to $32 billion in the year 2019.

These costs are necessary to keep insulin-dependent diabetes patients alive and healthy, but what if there was a different, potentially simpler solution to manage diabetes? One that looks to insulin-producing beta cells as the solution rather than daily hormone shots?

Douglas Melton Receives Stem Cell Prize for Work on Diabetes

Harvard scientist Douglas Melton envisions a world where one day, insulin-dependent diabetic patients are given stem cell transplants rather than shots to manage their diabetes. In the 90s, Melton’s son was diagnosed with type 1 diabetes. Motivated by his son’s diagnosis, Melton dedicated the focus of his research on understanding how beta cells develop from stem cells in the body and also in a cell culture dish.

Almost 30 years later, Melton has made huge strides towards understanding the biology of beta cell development and has generated methods to “reprogram” or coax pluripotent stem cells into human beta cells.

Melton was honored for his important contributions to stem cell and diabetes research at the second annual Ogawa-Yamanaka Stem Cell Prize ceremony last week at the Gladstone Institutes. This award recognizes outstanding scientists that are translating stem cell research from the lab to clinical trials in patients.

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Deepak Srivastava, director of the Gladstone Institute of Cardiovascular Disease, explained why Melton was selected as this year’s prize winner:

Deepak Srivastava, Gladstone Institutes

Deepak Srivastava, Gladstone Institutes

“Doug’s research on genetic markers expressed during pancreas development have led to a reliable way to reprogram stem cells into human beta cells. His work provides the foundation for the ultimate goal of transplantable, patient-specific beta cells.”

 

Making Beta Cells for Patients

During the awards ceremony, Melton discussed his latest work on generating beta cells from human stem cells and how this technology could transform the way insulin-dependent patients are treated.

Douglas Melton, Harvard University.

Douglas Melton, Harvard University.

“I don’t mean to say that this [insulin treatment] isn’t a good idea. That’s keeping these people alive and in good health,” said Melton during his lecture. “What I want to talk about is a different approach. Rather than making more and better insulins and providing them by different medical devices, why not go back to nature’s solution which is the beta cells that makes the insulin?”

Melton first described his initial research on making pancreatic beta cells from embryonic and induced pluripotent stem cells in a culture dish. He described the power of this system for not only modeling diabetes, but also screening for potential drugs, and testing new therapies in animal models.

He also mentioned how he and his colleagues are developing methods to manufacture large amounts of human beta cells derived from pluripotent stem cells for use in patients. They are able to culture stem cells in large spinning flasks that accelerate the growth and development of pluripotent stem cells into billions of human beta cells.

Challenges and Future of Stem-Cell Derived Diabetes Treatments

Melton expressed a positive outlook for the future of stem cell-derived treatments for insulin-dependent diabetes, but he also mentioned two major challenges. The first is the need for better control over the methods that make beta cells from stem cells. These methods could be more efficient and generate higher numbers of beta cells (beta cells make up 16% of stem cell-derived cells using their current culturing methods). The second is preventing an autoimmune attack after transplanting the stem-cell derived beta cells into patients.

Melton and other scientists are already working on improving techniques to make more beta cells from stem cells. As for preventing transplanted beta cells from being attacked by the patient’s immune system, Melton described two possibilities: using an encapsulation device or biological protection to mask the transplanted cells from an attack.

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He mentioned a CIRM-funded clinical trial by ViaCyte, which is testing an encapsulation device that is placed under the skin. The device contains embryonic stem cell-derived pancreatic progenitor cells that develop into beta cells that secrete insulin into the blood stream. The device also prevents the immune system from attacking and killing the beta cells.

Melton also discussed a biological approach to protecting transplanted beta cells. In collaboration with Dan Anderson at MIT, they coated stem cell-derived beta cells in a biomaterial called alginate, which comes from seaweed. They injected alginate microcapsule-containing beta cells into diabetic mice and were able control their blood sugar levels.

At the end of his talk, Melton concluded that he believes that beta cell transplantation in an immunoprotective device containing stem cell-derived cells will have the most benefit for diabetes patients.

Gladstone Youtube video of Douglas Melton’s lecture at the Ogawa-Yamanaka Prize lecture.


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Scientists Make Insulin-Secreting Cells from Stem Cells of Type 1 Diabetes Patients

Stem cell research for diabetes is in a Golden Age. In the past few years, scientists have developed methods to generate insulin-secreting pancreatic beta cell-like cells from embryonic stem cells, induced pluripotent stem cells (iPS cells), and even directly from human skin. We’ve covered a number of recent studies in this area on our blog, and you can read more about them here.

Patients with type 1 diabetes (T1D) suffer from an autoimmune response that attacks and kills the beta cells in their pancreas. Without these important cells, patients can no longer secrete insulin in response to increased glucose or sugar levels in the blood. Cell replacement is evolving into an attractive therapeutic option for patients with T1D. Replacing lost beta cells in the pancreas is a more permanent and less burdensome solution than the daily insulin shots that many T1D patients currently take.

Cell replacement therapy for type 1 diabetes

Stem cells are the latest strategy that scientists are pursuing for T1D cell replacement therapy. The strategy involves generating beta cells from pluripotent stem cells, either embryonic or iPS cells, that function similarly to beta cells found in a healthy human pancreas. Making beta cells from a patient’s own iPS cells is the ideal way to go because this autologous form (self to self) of transplantation would reduce the chances  of transplant rejection because a patient’s own cells would be put back into their body.

Scientists have generated beta cell-like cells from iPS cells derived from T1D patients previously, but the biological nature and function of these cells wasn’t up to snuff in a side by side comparison with beta cells from non-diabetic patients. They didn’t express the appropriate beta cell markers and failed to secrete the appropriate levels of insulin when challenged in a dish and when transplanted into animal models.

However, a new study published yesterday in Nature Communications has overcome this hurdle. Teams from the Washington University School of Medicine in St. Louis and the Harvard Stem Cell Institute have developed a method that makes beta cells from T1D patient iPS cells that behave very similarly to true beta cells. This discovery has the potential to offer personalized stem cell treatments for patients with T1D in the near future.

These beta cells could be the real deal

Their current work is based off of an earlier 2014 study – from the lab of Douglas Melton at Harvard – that generated functional human beta cells from both embryonic and iPS cells of non-diabetic patients. In the current study, the authors were interested in learning whether it was possible to generate functional beta cells from T1D patients and whether these cells would be useful for transplantation given that they could potentially be less functional than non-diabetic beta cells.

The study’s first author, Professor Jeffrey Millman from the Washington University School of Medicine, explained:

Jeffrey Millman

Jeffrey Millman

“There had been questions about whether we could make these cells from people with type 1 diabetes. Some scientists thought that because the tissue would be coming from diabetes patients, there might be defects to prevent us from helping the stem cells differentiate into beta cells. It turns out that’s not the case.”

After generating beta cells from T1D iPS cells, Millman and colleagues conducted a series of experiments to test the beta cells both in a dish and in mice. They found that the T1D-derived beta cells expressed the appropriate beta cell markers, secreted insulin in the presence of glucose, and responded well to anti-diabetic drugs that stimulated the beta cells to secrete even more insulin.

When T1D beta cells were transplanted into mice that lacked an immune system, they survived and functioned similarly to transplanted non-diabetic beta cells. When the mice were treated with a drug that killed off their mouse beta cells, the surviving human T1D beta cells were successful in regulating the blood glucose levels in the mice and kept them alive.

Beta cells derived from type 1 diabetes patient stem cells (top) express the same beta cell markers as beta cells derived from non-diabetic (ND) patients.

Beta cells derived from type 1 diabetes patient stem cells (top) express the same beta cell markers as beta cells derived from non-diabetic (ND) patients. (Nature Communications)

Big Picture

The authors concluded that the beta cells they generated from T1D iPS cells were indistinguishable from healthy beta cells derived from non-diabetic patients. In a news release, Millman commented on the big picture of their study:

“In theory, if we could replace the damaged cells in these individuals with new pancreatic beta cells — whose primary function is to store and release insulin to control blood glucose — patients with type 1 diabetes wouldn’t need insulin shots anymore. The cells we’ve manufactured sense the presence of glucose and secrete insulin in response. And beta cells do a much better job controlling blood sugar than diabetic patients can.”

He further commented that the T1D- derived beta cells “could be ready for human research in three to five years. At that time, Millman expects the cells would be implanted under the skin of diabetes patients in a minimally invasive surgical procedure that would allow the beta cells access to a patient’s blood supply.”

“What we’re envisioning is an outpatient procedure in which some sort of device filled with the cells would be placed just beneath the skin,” he said.

In fact, such devices already exist. CIRM is funding a type 1 diabetes clinical trial sponsored by the San Diego based company ViaCyte. They are currently testing a combination drug delivery system that implants a medical device capsule containing pancreatic progenitor cells derived from human embryonic stem cells. Once implanted, the progenitor cells are expected to specialize into mature pancreatic cells including beta cells that secrete insulin.


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Stem cells from “love-handles” could help diabetes patients

Love handles usually get a bad rap, but this week, a study from Switzerland claims that stem cells taken from the fat tissue of “love handles” could one day benefit diabetes patients.

An islet of a mouse pancreas containing beta cells shown in green. (wikipedia)

An islet of a mouse pancreas containing beta cells shown in green. (wikipedia)

The study, which was published in Nature Communications, generated the much coveted insulin-secreting pancreatic beta cells from human induced pluripotent stem cells (iPS cells) in a dish. When exposed to glucose (sugar), beta cells secrete the hormone insulin, which can tell muscle and fat tissue to absorb excess glucose if there is too much around. Without these important cells, your body wouldn’t be able to regulate the sugar levels in your blood, and you would be at high risk for getting diabetes.

Diabetic patients can take daily shots of insulin to manage their disease, but scientists are looking to stem cells for a more permanent solution. Their goal is to make bonafide beta cells from human pluripotent stem cells in a dish that behave exactly the same as ones living in a normal human pancreas. Current methods to make beta cells from stem cells are complex, too often yield inconsistent results and generate multiple other cell types.

Turning fat tissue into pancreatic cells

The Switzerland study developed a novel method for making beta cells from iPS cells that is efficient and gives more consistent results. The iPS cells were genetically reprogrammed from mesenchymal stem cells that had been extracted from the fat tissue of a 50-year old woman. To create insulin-secreting beta cells, the group developed a synthetic control network that directed the iPS cells step by step down the path towards becoming pancreatic beta cells.

The synthetic control network coordinated the expression of genes called transcription factors that are important for pancreatic development. The network could be thought of as an orchestra. At the start of a symphony, the conductor signals to different instrument groups to begin and then directs the tempo and sound of the performance, making sure each instrument plays at the right time.

In the case of this study, the synthetic gene network coordinates expression of three pancreatic transcription factors: Ngn2, Pdx1, and MafA. When the expression of these genes was coordinated in a precise way that mimicked natural beta cell development, the pancreatic progenitor cells developed into functioning beta-like cells that secreted insulin in the presence of glucose.

The diagram shows the dynamics of the most important growth factors during differentiation of human induced pluripotent stem cell to beta-like cells. Credit: ETH Zurich

The diagram shows the dynamics of the most important transcription factors during differentiation of human induced pluripotent stem cell to beta-like cells. Credit: ETH Zurich

Pros of love handle-derived beta cells

This technology has advantages over current stem cell-derived beta cell generating methods, which typically use combinations of genetic reprogramming factors, chemicals, or proteins. Senior author on the study, Martin Fussenegger, explained in a news release that his study’s method has more control over the timing of pancreatic gene expression and as a result is more efficient, having the ability to turn three out of four fat stem cells into functioning beta cells.

Another benefit to this technology is the potential for making personalized stem cell treatments for diabetes sufferers. Patient-specific beta cells derived from iPS cells can be transplanted without fear of immune rejection (it’s what’s called an autologous stem cell therapy). Some diabetes patients have received pancreatic tissue transplants from donors, but they have to take immunosuppressive drugs and even then, there is no guarantee that the transplant will survive and work properly for an extended period of time.

Fussenegger commented:

“With our beta cells, there would likely be no need for this action, since we can make them using endogenous cell material taken from the patient’s own body. This is why our work is of such interest in the treatment of diabetes.”

More work to do

While these findings are definitely exciting, there is still a long road ahead. The authors found that their beta cells did not perform at the same level as natural beta cells. When exposed to glucose, the stem cell-derived beta cells failed to secrete the same amount of insulin. So it sounds like the group needs to do some tweaking with their method in order to generate more mature beta cells.

Lastly, it’s definitely worth looking at the big picture. This study was done in a culture dish, and the beta cells they generated were not tested in animals or humans. Such transplantation experiments are necessary to determine whether love-handle derived beta cells will be an appropriate and effective treatment for diabetes patients.

A CIRM funded team at San Diego-based company ViaCyte seems to have successfully gotten around the issue of maturing beta cells from stem cells and is already testing their therapy in clinical trials. Their study involves transplanting so-called pancreatic progenitor cells (derived from embryonic stem cells) that are only part way down the path to becoming beta cells. They transplant these cells in an encapsulated medical device placed under the skin where they receive natural cues from the surrounding tissue that direct their growth into mature beta cells. Several patients have been transplanted with these cells in a CIRM funded Phase 1/2 clinical trial, but no data have been released as yet.


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Stem cell stories that caught our eye: sexual identity of organs, upping the game of muscle stem cells, mini guts produce insulin

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.

A new sexual identity crisis—in our organs. With the transition from Mr. to Ms. Jenner and other transsexual news this year, it seems inevitable that a research paper would come out suggesting we may all have some mosaic sexual identity. A team in the U.K. found that the stem cells that develop our organs can have varying sexual identities and that can impact the function of the organ.

The organ in question in this case, intestines in fruit flies, is smaller in males than in females. By turning on and off certain genes the researchers at the Medical Research Council’s Clinical Science Centre found that making stem cells in the gut more masculine reduced their ability to multiply and produced smaller intestines. They also found that female intestines were more prone to tumors, just as many diseases are more common in one sex than the other.

In an interview with Medical News Today, Bruno Hudry, the first author on the paper, which is published in Nature, talked about the likelihood that we all have some adult cells in us with genes of the opposite sex.

 “This study shows that there is a wider spectrum than just two sexes. You can be chromosomally, hormonally or phenotypically female but still having some specific adult stem cells (here the stem cells of the intestine) acting like male. So it is hard to say if someone is “really” male or female. Some people are simply a mosaic of male and female cells within a phenotypically ‘male’ or ‘female’ body.”

Hurdry speculated that if the results are duplicated in humans it could provide a window into other sex-linked differences in diseases and could be a matching factor added to the standard protocol for blood and organ donations.

 

Reprogramming stomach to produce insulin.  The stem cells in our gut show an efficiency not seen in most of our organs. They produce a new lining for our stomach and intestine every few days. On the opposite end of the spectrum, the insulin-producing cells in our pancreas rank poorly in self renewal. So, what if you could get some of those vigorous gut stem cells to make insulin producing beta cells? Turns out you can and they can produce enough insulin to allow a diabetic mouse to survive.

mini stomach

A mini-gut with insulin-producing cells (red) and stem cells (green).

A team at the Harvard Stem Cell Institute manipulated three genes known to be associated with beta cell development and tested the ability of many different tissues—from tail to snout—to produce beta cells. A portion of the stomach near the intestine, which naturally produces other hormones, easily reprogrammed into insulin producing cells. More important, if the first batch of those cells was destroyed by the team, the remaining stem cells in the tissue quickly regenerated more beta cells. Since a misbehaving immune system causes type 1 diabetes, this renewal ability could be key to preventing a return of the disease after a transplant of these cells.

In the lab the researchers pushed the tissue from the pylorous region of the stomach to self-organize into mini-stomachs along with the three genetic factors that drive beta cell production.  When transplanted under the skin of mice that had previously had their beta cells destroyed, the mice survived. The genetic manipulations used in this research could not be used in people, but the team is working on a system that could.

 “What is potentially really great about this approach is that one can biopsy from an individual person, grow the cells in vitro and reprogram them to beta cells, and then transplant them to create a patient-specific therapy,” said Qiao Zhou, the senior author. “That’s what we’re working on now. We’re very excited.”

Medicalxpress ran a story about the work published in Cell Stem Cell.

 

muscle stem cells

Muscle stem cells generate new muscle (green) in a mouse.

Better way to build muscle.  Stem cells behave differently depending on what environment they find themselves in, but they are not passive about their environment. They can actively change it. A CIRM-funded team at Sanford Burnham Prebys Medical Discovery Institute (SBP) found that fetal muscle stem cells and adult muscle stem cells make very different changes in the micro-environment around them.

Fetal muscle stem cells become very good at generating large quantities of new muscle, while the adult stem cells take the role of maintaining themselves for emergencies. As a result, when major repair is needed like in muscular dystrophies and aging, they easily get overwhelmed. So the SBP team looked for ways to make the adult stem cells behave more like their fetal predecessors.

 “We found that fetal MuSCs remodel their microenvironment by secreting specific proteins, and then examined whether that same microenvironment can encourage adult MuSCs to more efficiently generate new muscle. It does, which means that how adult MuSCs normally support muscle growth is not an intrinsic characteristic, but can be changed,” said Matthew Tierney, first author of the study in an institute press release distributed by Newswise.

The results point to paths for developing therapies for a number of muscle wasting conditions.

Protective cell therapy could mean insulin independence for diabetic patients

This has already been a productive year for diabetes research. Earlier this month, scientists from UCSF and the Gladstone Institutes successfully made functional human pancreatic beta cells from skin, providing a new and robust method for generating large quantities of cells to replace those lost in patients suffering from type 1 diabetes.

Today marks another breakthrough in the development of stem cell therapies for diabetes. Scientists from MIT and the Harvard Stem Cell Institute published a new method in Nature Medicine that encapsulates and protects stem cell-derived pancreatic beta cells in a way that prevents them from being attacked by the immune system after transplantation.

Protecting transplanted cells from the immune system

Stem cell therapy holds promise for diabetes for a number of reasons. First, scientists now have the ability to generate large numbers of insulin producing pancreatic beta cells from human skin and stem cells. This obviates the need for donor beta cells, which are always in short supply and high demand. Second, there’s the issue of the immune system. Transplanting beta cells from a donor into a patient will trigger an immunological reaction, which can only be abated by a lifetime regimen of immunosuppressive drugs.

One way that scientists have addressed the issue of immune rejection is to transplant stem cell-derived beta cells in a protected capsule. A CIRM-funded company called ViaCyte has developed a medical device that acts like a replacement pancreas but is surgically implanted under the skin. It contains human beta cells derived from embryonic stem cells and has a membrane barrier that allows only certain molecules to pass in and out of the device. This way, the foreign pancreatic cells are shielded from the immune system, but they can still respond to changing blood sugar levels in the patient by secreting insulin into the blood stream.

Another way that scientists trick the immune system in diabetes patients uses a similar strategy but instead of a medical device that protects a large population of cells, they encapsulate individual islets (clusters of beta cells) using biomaterials.

However, previous attempts using a biomaterial called alginate to encapsulate islets caused an immune response in the form of fibrosis, or scar tissue, and cell death. Additionally, transplanted alginate microspheres were only able to achieve glycemic control, or control of blood sugar levels, temporarily in animal models.

In the Nature Medicine study, the scientists developed a new method for beta cell encapsulation where they used a chemically modified version of the alginate microspheres – triazole-thiomorpholine dioxide (TMTD) – that didn’t cause an immune reaction and was able to maintain glycemic control in mice that had diabetes.

New protective method makes diabetic mice insulin independent

The scientists tested the conventional alginate microspheres and the modified TMTD-alginate microspheres containing embryonic stem cell-derived human beta islets in diabetic mice.

Encapsulated beta islets were transplanted into diabetic mice. (Nature Medicine)

Encapsulated beta islets were transplanted into diabetic mice. (Nature Medicine)

They found that the conventional smaller alginate microspheres caused fibrosis while larger TMTD-alginate microspheres did not. They observed that the modified TMTD-alginate microspheres were able to achieve glycemic control for over 70 days after transplantation while conventional microspheres didn’t perform as well.

The scientists also looked at the immune response to both types of alginate spheres. They saw lower numbers of immune cells and less fibrosis surrounding the transplanted TMTD microspheres compared to the conventional microspheres.

The final studies were the icing on the cake. The asked whether the modified TMTD microspheres were able to maintain long-term glycemic control or insulin independence, which would mean sustaining blood glucose levels in diabetic mice for over 100 days. They studied diabetic mice that received TMTD microspheres for 174 days. At 150 days, they performed a glucose test and saw that the diabetic mice were just as good at regulating glucose levels as normal mice. Furthermore, after 6 months, these mice showed no build up of fibrotic tissue, indicating that the modified microspheres weren’t causing an immune response and these mice didn’t need immunosuppressive drugs.

What the experts had to say…

This study was picked up by STATnews, which also mentioned another related study published in Nature Biotechnology that tested various alginate derivatives in rodent and monkey models of diabetes.

Julia Greenstein, vice president of discovery research at JDRF, discussed the implications of both studies with STATnews:

“This is really the first demonstration of the ability of these novel materials in combination with a stem-cell derived beta cell to reverse diabetes in an animal model. Our goal is to bring that kind of biological cure across the spectrum of type 1 diabetes.”

First author on both studies, Arturo Vegas, also gave his thoughts and discussed future applications:

Arturo Vegas

Arturo Vegas

“From very early on, we were getting great success. Everything kind of fell into place. You saw less foreign body response. The human beta cells survived exquisitely well. I think we’ve advanced the ball pretty far, almost as far you could get in an academic environment. The talk is shifting toward doing something clinically.”

According to STATnews, Vegas and his team are working on tests now in monkey models. “Vegas said that if the primate studies are successful, the next step will be developing a therapy to be used in people.”


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A Win for Diabetes: Scientists Make Functional Pancreatic Cells From Skin

Today is an exciting day for diabetes research and patients. For the first time, scientists have succeeded in making functional pancreatic beta cells from human skin. This new method for making the insulin-producing cells of the pancreas could produce a new, more effective treatment for patients suffering from diabetes.

Researchers at the Gladstone Institutes and the University of California, San Francisco published these promising findings today in the journal Nature Communications.

Making pancreatic cells from skin

They used a technique called direct reprogramming to turn human skin cells directly into pancreatic beta cells without having to go all the way back to a pluripotent stem cell state. The skin cells were treated with factors used to generate induced pluripotent stem cells (iPSCs) and with pancreatic-specific molecules. This cocktail of factors and molecules shut off the skin genes and turned on genes of the pancreas.

The end product was endoderm progenitor cells, which are like stem cells but can only generate cell types specific to organs derived from the endoderm layer (for example: lungs, thyroid, pancreas). The scientists took these endoderm progenitors and further coaxed them into mature, pancreatic beta cells after treatment with another cocktail of molecules.

Functioning human pancreatic cells after they’ve been transplanted into a mouse. (Image: Saiyong Zhu, Gladstone)

Functioning human pancreatic cells after they’ve been transplanted into a mouse. (Image: Saiyong Zhu, Gladstone)

While the pancreatic cells they made looked and acted like the real thing in a dish (they were able to secrete insulin when exposed to glucose), the authors needed to confirm that they functioned properly in animals. They transplanted the mature beta cells into mice that were engineered to have diabetes, and observed that the human beta cells protected the mice from becoming diabetic by properly regulating their blood glucose levels.

Importantly, none of the mice receiving human cells got tumors, which is always a concern when transplanting reprogrammed cells or cells derived from pluripotent stem cells.

What does this mean?

This study is groundbreaking because it offers a new and more efficient method to make functioning human beta cells in mass quantities.

Dr. Sheng Ding, a CIRM funded senior investigator at the Gladstone and co-senior author, explained in a Gladstone news release:

Sheng Ding

Sheng Ding

“This new cellular reprogramming and expansion paradigm is more sustainable and scalable than previous methods. Using this approach, cell production can be massively increased while maintaining quality control at multiple steps. This development ensures much greater regulation in the manufacturing process of new cells. Now we can generate virtually unlimited numbers of patient-matched insulin-producing pancreatic cells.”

 

Matthias Hebrok, director of the Diabetes Center at UCSF and co-senior author on paper discussed the potential research and clinical applications of their findings:

Mattias Hebrok

Matthias Hebrok

“Our results demonstrate for the first time that human adult skin cells can be used to efficiently and rapidly generate functional pancreatic cells that behave similar to human beta cells. This finding opens up the opportunity for the analysis of patient-specific pancreatic beta cell properties and the optimization of cell therapy approaches.”

 

The study does mention the caveat that their direct reprogramming approach wasn’t able to generate all the cell types of the pancreas. Having these support cells would better recreate the pancreatic environment and likely improve the function of the transplanted beta cells.

Lastly, I find this study exciting because it kills two birds with one stone. Scientists can use this technique to make better cellular models of diabetes to understand why the disease happens, and they could also develop new cell replacement therapies in humans. Already, stem cell derived pancreatic beta cells are being tested in human clinical trials for type 1 diabetes (one of them is a CIRM-funded clinical trial by Viacyte) and it seems likely that beta cells derived from skin will follow suit.


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Stem cell stories that caught our eye: new ways to reprogram, shifting attitudes on tissue donation, and hockey legend’s miracle questioned

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.

Insulin-producing cells produced from skin. Starting with human skin cells a team at the University of Iowa has created iPS-type stem cells through genetic reprogramming and matured those stem cells into insulin-producing cells that successfully brought blood-sugar levels closer to normal when transplanted in mice.

University of Iowa researchers reprogrammed human skin cells to create iPS cells, which were then differentiated in a stepwise fashion to create insulin-producing cells. When these cells were transplanted into diabetic mice, the cells secreted insulin and reduced the blood sugar levels of the mice to normal or near-normal levels. The image shows the insulin-producing cells (right) and precursor cells (left). [Credit: University of Iowa]

University of Iowa researchers reprogrammed human skin cells to create iPS cells, which were then differentiated in a stepwise fashion to create insulin-producing cells. When these cells were transplanted into diabetic mice, the cells secreted insulin and reduced the blood sugar levels of the mice to normal or near-normal levels. The image shows the insulin-producing cells (right) and precursor cells (left).
[Credit: University of Iowa]

The cells did not completely restore blood-sugar levels to normal, but did point to the possibility of achieving that goal in the future, something the team leader Nicholas Zavazava noted in an article in the Des Moines Register, calling the work an “encouraging first step” toward a potential cure for diabetes.

The Register discussed the possibility of making personalized cells that match the genetics of the patient and avoiding the need for immune suppression. This has long been a goal with iPS cells, but increasingly the research community has turned to looking for options that would avoid immune rejection with donor cells that could be off-the-shelf and less expensive than making new cells for each patient.

Heart cells from reprogramming work in mice. Like several other teams, a group in Japan created beating heart cells from iPS-type stem cells. But they went the additional step of growing them into sheets of heart muscle that when transplanted into mice integrated into the animals own heart and beat to the same rhythm.

The team published the work in Cell Transplantation and the news agency AlianzaNews ran a story noting that it has previously been unclear if these cells would get in sync with the host heart muscle. The result provides hope this could be a route to repair hearts damaged by heart attack.

Patient attitudes on donating tissue. A University of Michigan study suggests most folks don’t care how you use body tissue they donate for research if you ask them about research generically. But their attitudes change when you ask about specific research, with positive responses increasing for only one type of research: stem cell research.

On the generic question, 69 percent said go for it, but when you mentioned the possibility of abortion research more than half said no and if told the cells might lead to commercial products 45 percent said nix. The team published their work in the Journal of the American Medical Association and HealthCanal picked up the university’s press release that quoted the lead researcher, Tom Tomlinson, on why paying attention to donor preference is so critical:

“Biobanks are becoming more and more important to health research, so it’s important to understand these concerns and how transparent these facilities need to be in the research they support.”

CIRM has begun building a bank of iPS-type stem cells made from tissue donated by people with one of 11 diseases. We went through a very detailed process to develop uniform informed consent forms to make sure the donors for our cell bank knew exactly how their cells could be used. Read more about the consent process here.

Mainstream media start to question hockey legend’s miracle. Finally some healthy skepticism has arrived. Hockey legend Gordie Howe’s recovery from a pair of strokes just before the holidays was treated by the general media as a true Christmas miracle. The scientific press tried to layer the coverage with some questions of what we don’t know about his case but not the mainstream media. The one exception I saw was Brad Fikes in the San Diego Union Tribune who had to rely on a couple of scientists who were openly speaking out at the time. We wrote about their concerns then as well.

Now two major outlets have raised questions in long pieces back-to-back yesterday and this morning. The Star in hockey-crazed Canada wrote the first piece and New York Magazine wrote today’s. Both raise serious questions about whether stem cells could have been the cause of Howe’s recovery and are valuable additions to the coverage.