Tag Archives: pluripotent stem cells

Japanese woman is first recipient of next-generation stem cells

Researchers were able to grow sheets of retinal tissue from induced pluripotent stem cells, and have now implanted them for the first time in a patient.

Researchers were able to grow sheets of retinal tissue from induced pluripotent stem cells, and have now implanted them for the first time in a patient. RIKEN/Foundation for Biomedical Research and Innovation

A Japanese woman in her 70s is the world’s first recipient of cells derived from induced pluripotent stem cells, a technology that promises to work wonders and has the scientific community excited about the perspectives. Surgeons working on the case created the retinal tissue after reverting the patient’s own cells to ‘pluripotent’ state.

If you’d like to benefit from stem cells, but you’re worried that you haven’t had cells harvested early enough – then stop worrying, the next level technology is already here, offering the same advantages as embryo-derived cells but without some of the controversial aspects and safety concerns.

The two hour procedure took place a mere four days after the health-ministry committee gave Takahashi clearance to begin human trials; previously, it had been safely conducted on rats and mice. The surgery’s objective was transplanting a 1.3 by 3.0 millimeter sheet of retinal pigment epithelium cells into an eye of an elderly Japanese woman suffering from age-related macular degeneration.

Yasuo Kurimoto of the Kobe City Medical Center General Hospital led the procedure, accompanied by a team of three other specialists.

“[She] took on all the risk that go with the treatment as well as the surgery”, Kurimoto said in a statement released by RIKEN. “I have deep respect for bravery she showed in resolving to go through with it.”

Kurimoto also took a moment to acknowledge the work of Yoshiki Sasai, a researcher who recently committed suicide. Yoshiki Sasai, deputy director of the RIKEN Center for Developmental Biology (CDB) in Kobe was one of the most brilliant minds working in stem cell research, but a scandal swirling around two stem-cell papers published in Nature in January had wreaked havoc on his career.

“This project could not have existed without the late Yoshiki Sasai’s research, which led the way to differentiating retinal tissue from stem cells.”

Sadly enough, Sasai’s downfall wasn’t even his own doing – one of his proteges, Haruko Obokata, then a visiting researcher, manipulated the results of two research papers on which Sasai also worked. In Japan, the media rained criticism on Sasai, including unsubstantiated accusations; despite the fact that he himself did not contribute to the forgery, he didn’t check the facts close enough. This immense pressure eventually led him to commit suicide.

Yoshiki Sasai. Nature.

But the results of his work are still alive today, and show much promise for future research. Even in a patient over 70 years old, the procedure will ensure that future degeneration doesn’t take place anymore, although it is less likely to restore vision to what it was before degeneration.

“We’ve taken a momentous first step toward regenerative medicine using iPS cells,” Takahashi said in a statement. “With this as a starting point, I definitely want to bring [iPS cell-based regenerative medicine] to as many people as possible.”

brown pig

Chimeric organ harvesting: growing human organs inside pigs

brown pig

Photo: freefoto.com

Sure to raise a slew of controversy and debate, researchers in Japan are currently investigating the possibility of growing human organs, like kidneys, livers or even hearts, inside pigs. A real life chimeric tale, as if spawned from the Island of Dr. Moreau. The challenges are numerous though, both technical (we’re talking about growing human organs in a foreign host), legal (human-animal hybrids are illegal in Japan) and of course moral (do we want living, breathing, organ farms – how would it be different from meat farms today?). For now, we can only entertain and ponder these questions, but in Japan things are beginning to shape up towards this goal.

The first steps in this direction were made by Hiroshi Nagashima, a professor at Meiji University, who made chimeric pigs – pigs that contain the genetic signature of two different species. A pilot experiment involved the breeding of what’s called an “a-pancreatic” pig. The genes that code the development of the pancreas in white pigs was switched off, then stem cells from a black pig are introduced into the white pig embryo. When the baby pig is born, it will look like a normal white pig, except it will have a black pig pancreas.

[RELATED] First chimera monkeys presented to the world

At Tokyo University, Professor Hiro Nakauchi is taking things further, by using induced pluripotent stem cells (iPS) – adult cell that are culture and hoaxed into behaving like stem cells, without the need to harvest stem cells from embryos. Nakauchi and team cultured iPS cells from brown mice skin cells and introduced these in the embryos of white mice, which similarly to Nagashima’s research had their pancreas development gene turned off. Nakauchi ended up with a white mouse with a brown mouse pancreas. The beauty of iPS cells, however, is that they can be used to develop into any kind of cells, like the constituting tissue that makes up organs. This is the basis for growing human organs in the lab, something that is currently in development with mixed results.

Man and beast

The Japanese researchers hope they can ultimately grow a human organ inside a pig host, or maybe some other surrogate animal model for that matter. If successful, the human organ grown would theoretically be identical to the human organ needing replacement, since it would have been grown from the patient’s iPS cells. The medical implications would be outstanding. Millions of people all over the world require an organ transplant of some kind and for many the waiting list is too long for survival.  Organs grown this way would actually be ideal, since there wouldn’t be a case of biological incompatibility anymore.

Is such a thing possible in the first place?

Black pig pancreas in a white pig host. Brown mouse pancreas in a white mouse host. Human pancreas inside a pig. Obviously, the latter case doesn’t follow the same pattern. We’re talking about extremely distant species. With confidence, however,  Prof Nakauchi  claims it can be done. In Japan human-animal hybrids are illegal and if any of his research can go further, the laws need to be changed. If not, Nakauchi can always move his research to a more permissive country.

Footage from the movie "The Island of Dr. Moreau".

Footage from the movie “The Island of Dr. Moreau”.

Then there’s another concern. In HG Wells’ sci-fi classic, The Island of Dr Moreau, an oddball scientists breeds all sort of chimeric creatures – grotesque beings that are horse, dog and pig at the same time (M’ling). Nakauchi assures that the genetically engineered pigs would still be pigs, it’s just that they’d be carrying human tissue. Anticipating controversy, the Japanese scientist points to In Vitro Fertilisation (IVF) which was invented in Britain in the 1970’s and which at the time sparked a lot of debate. Today, IVF is no longer seen as strange or unethical and in time Nakauchi’s research may also become accepted if the results measure up, he says.

 

(C) Nature Biotechnology

First functioning lung and airway cells grown from human stem cells

Biotechnology is growing fast and the findings researchers are making the field are nothing short of breathtaking. Previously, ZME Science reported in the past few years alone a series of milestone premiers: the first bioengineered kidney and 3-D human kidney cells, the  first functioning blood vessels, the first teeth-like structures, a bioengineered heart that beats on its own and many more. All of these vital tissue and precursor organs were grown in the lab using stem cells or induced pluripotent stem cells. Now, yet another milestone confirms the growing trend after researchers at Columbia University Medical Center reported they’ve created functioning lung and airway cells.

(C) Nature Biotechnology

(C) Nature Biotechnology

Lung transplants are among the most complicated medical procedures, and patients have one of the poorest prognosis post-transplant. This is because it’s very difficult to find biocompatible lungs for transplant. Growing new lungs in the lab directly from patients’ cells, however, offers a massive workaround. More or less, the resulting lung would be very similar to the one the patient loses during transplant, greatly reducing the chance the immune system will reject the lung. Growing organs may seem like SciFi and although we’re still far away from seeing a fully fledged, lab-grown organ becoming successfully transplanted, we’re getting there.

“Now, we are finally able to make lung and airway cells,” study leader Dr. Hans-Willem Snoeck, a professor of microbiology and immunology at Columbia University in New York, said in a statement.

A breath of fresh air

Previously, Snoeck and team discovered a set of chemical factors that can turn human embryonic stem (ES) cells or human induced pluripotent stem (iPS) cells (adult skin cells that have been reprogrammed into stem cells) into anterior foregut endoderm – precursors of lung and airway cells.  Now, the same researchers have found a set of chemicals that coax stem cells in growing into epithelial cells which coat the surface of lungs.

In fact, resultant cells were found to express markers of at least six types of lung and airway epithelial cells, particularly markers of type 2 alveolar epithelial cells. The kind of cells are vital because they produce  surfactant, a substance critical to maintain the lung alveoli, where gas exchange takes place; they also participate in repair of the lung after injury and damage.

 “Now, we are finally able to make lung and airway cells. This is important because lung transplants have a particularly poor prognosis. Although any clinical application is still many years away, we can begin thinking about making autologous lung transplants — that is, transplants that use a patient’s own skin cells to generate functional lung tissue,” said the authors of the paper published in the journal Nature Biotechnology.

Transplants may be long away, but lab-grown lungs from diseased patients could serve a much more immediate purpose in the future. Early-stage precursor lungs could become highly valuable in research, where they could act as biological test beds for various types of drugs or kinds of treatment. This applies for virtually any kind of organ. Even in this primitive stage, testing could be made. For instance, idiopathic pulmonary fibrosis (IPF) is a lung disease  in which type 2 alveolar epithelial cells are thought to play a central role.

“No one knows what causes the disease, and there’s no way to treat it,” says Dr. Snoeck. “Using this technology, researchers will finally be able to create laboratory models of IPF, study the disease at the molecular level, and screen drugs for possible treatments or cures.”

“In the longer term, we hope to use this technology to make an autologous lung graft,” Dr. Snoeck said. “This would entail taking a lung from a donor; removing all the lung cells, leaving only the lung scaffold; and seeding the scaffold with new lung cells derived from the patient. In this way, rejection problems could be avoided.” Dr. Snoeck is investigating this approach in collaboration with researchers in the Columbia University Department of Biomedical Engineering.

“I am excited about this collaboration with Hans Snoeck, integrating stem cell science with bioengineering in the search for new treatments for lung disease,” said Gordana Vunjak-Novakovic, PhD, co-author of the paper and Mikati Foundation Professor of Biomedical Engineering at Columbia’s Engineering School and professor of medical sciences at Columbia University College of Physicians and Surgeons.

Mouse embryonic kidney cells (seen here in red) were used to coax the human stem cells to grow into the nascent mushroom-shaped buds (blue and green). (c) Salk Institute for Biological Studies

Kidney 3-d structures from human stem cells made for the first time

Scientists at the   Salk Institute for Biological Studies have for the first time coaxed   human stem cells into forming three-dimensional cellular structures similar to those found in our kidneys. The breakthrough could provide a valuable footing for upcoming work that might eventually lead to fully functioning lab-grown kidneys, based on patients’ own cells for bio-compatibility. In its current stage, lab-grown kidney-like structures such as the one developed by Salk researchers can be effectively used today as test beds for various kind of drugs.

In the U.S. alone some 4.4 million people are suffering from some form of kidney disease. Unlike other vital organs, the kidney rarely recover function once its damaged by disease; typically a transplant is required, and while treatment can alleviate symptoms and make life manageable, patients still need to make the plunge to surgery. Transplants are far too few for the current demand – growing bio-compatible kidneys would be a solution, and as you might imagine it’s an extremely challenging task.

Mouse embryonic kidney cells (seen here in red) were used  to coax the human stem cells to grow into the nascent mushroom-shaped buds (blue and green). (c) Salk Institute for Biological Studies

Mouse embryonic kidney cells (seen here in red) were used to coax the human stem cells to grow into the nascent mushroom-shaped buds (blue and green). (c) Salk Institute for Biological Studies

Previous methods have had limited success, however the present attempt successfully morphs  human stem cells into well-organized 3D structures of the ureteric bud (UB), which later develops into the collecting duct system.  Ureteric bud cells  are responsible for reabsorbing water after toxins have been filtered out and during embryonic development in the womb, later develop into a conduit for urine drainage from the kidney.  This was achieved using both human embryonic stem cells and induced pluripotent stem cells (iPSCs) – adult cells, like those harvested from the skin for instance, that are manipulated to behave like natural stem cells and thus later differentiate into any kind of cell.

[RELATED] First bio-engineered kidney works after transplant in rats 

First the researchers stimulated the stem cells or iPSCs to developed into mesoderm, a germ cell layer from which the kidneys develop using growth factors – cells that signal and offer cues to stem cells to differentiate into desired types of cells. In this instance, the researchers used mouse cells as growth factors.

The team tested their method by developing three-dimensional structures of the kidney via iPSCs harvested from  a patient clinically diagnosed with polycystic kidney disease (PKD) , a genetic disorder which can lead to kidney failure. So far, neither  gene- nor antibody-based therapies have proven to treat PKD, however using  their methodology it may be possible for pharmaceutical companies and other investigators studying drug-based therapeutics for PKD and other kidney diseases.

“Our differentiation strategies represent the cornerstone of disease modeling and drug discovery studies,” says lead study author Ignacio Sancho-Martinez, a research associate in Izpisua Belmonte’s laboratory. “Our observations will help guide future studies on the precise cellular implications that PKD might play in the context of kidney development. ”

Findings appeared in the journal Nature Cell Biology.

Brain like tissue developed in lab

Scientists grow brain-like tissue in petri dish

Most medical research looking to identify the mechanisms of a disease or test treatments rely on animal models. While very useful, mice for instance (a favorite lab pet for researchers) do not have nearly the same brain structure or genes as humans. Even if some genes and proteins scientists target are the same both in mice and humans, it will still be unclear whether a treatment will work for both organisms, something very important to keep in mind especially when preparing clinical trials.

The most sound alternative to this would be to culture human organs and cells for testing, and great strides forward have been made in this direction in the past decade alone.  Jürgen Knoblich and Madeline Lancaster, both researchers working in labs at the Austrian Academy of  Sciences,  are also part of this collective scientific effort of culturing human cells for research purposes. The researchers successfully grew hundreds of 4-mm white blobs of neurons from stem cells induced from adult skin cells. Remarkably, these blogs developed specialized regions, similar to the way a human brain would develop in utero.

Brain like tissue developed in lab

(c) Nature

Previously we’ve reported how other scientists had grown human lungs, kidneys and even a heart that beats on its own (all primitive versions, not really comparable yet to the natural counterpart), while other efforts have concentrated on culturing intestines, pituitaries, and simple retinas. Testing treatments on these lab grown structures helps scientist surmount some of the challenges that come with animal models, including animal cruelty in some cases. The brain, however, is far more complex than any of these and as such is very difficult to replicate in the lab.

Knoblich and colleagues first collected fibroblasts (collagen generating skin cells), and induced these to become stem cells (induced pluripotent stem cells). These cells were placed in a nutrient rich gel, which allowed them to replicate into a sort of big ball of cells, akin to the embryo development stage of typical brain in utero. Some of these cells became precusor cells for neural tissue. The innovative part came in the last stage, when the researchers placed their cultured cells into a bioreactor which helped spread and distribute nutrients into the primitive brain-like tissue much in the same blood vessels would deliver the nutrients in a ‘conventional’ developing brain. The resulting brain-like structures are called cerebral organoids.

“If you’re studying brain development, you would like to see the cells develop somewhat like a brain,” says Wynshaw-Boris, who wasn’t involved in the new study. “These organoids gradually differentiate into many different types of cells. It’s not really a brain, but seems to recapitulate brain development. This is much better than any of the past efforts, in terms of the number and types of cells.”

Using the spinning nutrient distribution provided by the bioreactor, the cultured organoids reached new levels of complexity compared to previous attempts, allowing them to develop in regions similar in composition (but not in complexity) to the brain’s cerebral cortex, choroid plexus, retina, and meninges.

A brain in a petri dish

What’s most interesting about the research is that not does it only show it’s possible to culture a brain or at least a brain-like tissue in the lab, but also to use it as a model to study diseases. The researchers grew organoids using skin cells taken from a patient with microcephaly – a disorder characterized by a dramatic reduction in the size of a person’s brain. The neural tissue hared many of the trademark features of microcephaly, including reduced size. The scientists infer that in people with microcephaly, the founding neural cells don’t replicate and differentiate properly in the developing embryo, later leading to a smaller brain.

Like most current attempts at culturing human organs, the cultured organoids are simple and lack the far reaching complexity of a mature brain – they’re millions of miles apart. . A developing brain contains blood vessels that deliver nutrients and energy with which to grow, but modern science hasn’t been able to fully duplicate those blood vessels yet – the same problem that pesters other researchers hard at work culturing human hearts for instance. In fact, Knoblich believes we won’t ever be able to develop a functioning human brain, the way we’re used to thinking of it at least. Even so, it would raise some serious ethical questions. Deep down in a lab grown functioning brain’s recesses, in a cold petri dish, would a human consciousness lurk? Would you be essentially growing a human being? Such discussions have been a subject of debate for many years concerning abortions, and this new research adds further food for thought.

Findings were reported in the journal Nature.

Decellularized Mouse Heart: Lu et. al

Scientists engineer heart in the lab that beats on its own

Regenerative medicine has come a long way, and while important strides forward have been made, scientists are still toiling with ways to completely grow organs in labs. There are millions of people worldwide suffering from afflictions to organs like the liver, lungs or heart – for many of them a transplant is they’re only chance at living a normal life again and even survive. Less than 1% of those on the waiting list actually receive a transplant, however, because of the sheer disproportion between donors and patients. Elaborating means of growing new organs in the lab ready for transplant and save lives is thus imperious. Work is though and slow, but signs are we’re getting there.

The latest breakthrough comes from researchers at University of Pittsburgh who recently report they’ve cultured a heart that can beat on its own. Unlike other cultured organs like the lungs or liver (still primitive, somewhat working, but not ready for transplant), the heart is the most difficult organ to build. Why? The heart beats, and building a heart in the lab that beats isn’t enough. It needs to beat at a certain rate, something controlled by the cardiovascular system, which needs to be reproduced. So you need to build a whole new system, not just the organ itself. Onto the scientists’ work, however.

Decellularized Mouse Heart:  Lu et. al

Decellularized Mouse Heart: Lu et. al

Like other regenerative efforts, the researchers used induced pluripotent stem cells to culture their heart. These cells are very similar to stem cells, only they’re collected from adult cells and forced to express certain genes. Using cells collected from blood, skin, stomach, even urine (we reported earlier how a group of researchers grew teeth-like structures using such cells), scientists can turn these into iPSCs and then morph them into whatever they like. So, basically, most of the features of stem cells (the differences between iPSCs and stem cells are still not fully understood), without the drawbacks – controversial embryonic collection, hard to come by etc. Most importantly, however, because the pluripotent stem cells are collected from mature cells – i.e. from the patient who needs the transplant – an organ grown from these will have a much slighter chance at being rejected by the host body.

“Scientists have been looking to regenerative medicine and tissue engineering approaches to find new solutions for this important problem. The ability to replace a piece of tissue damaged by a heart attack, or perhaps an entire organ, could be very helpful for these patients,” said Lei Yang, the lead researcher.

The approach Lei and his team used, however, is different in one key aspect from other iPSC-centered heart regeneration efforts. They first let the stem cells begin to develop for six days, such that some of them may differentiate into  cardiovascular progenitor cells.

The heart of mouse was subsequently collected and had all its cells removed besides the underling structure – leaving a sort of scaffold. Onto this scaffold the cardiovascular cells developed from human induced stem cells were laid. So, contrary to previous methods where the risk of some stem cells developing into liver cells for instance is present, the Pittsburgh team’s approach rendered more functioning heart cells – the denser the heart cells are in the organ the better the chance it has of working closer to the natural thing.

“This process makes MCPs, which are precursor cells that can further differentiate into three kinds of cells the heart uses, including cardiomyocytes, endothelial cells and smooth muscle cells,” Dr. Yang explained. “Nobody has tried using these MCPs for heart regeneration before. It turns out that the heart’s extracellular matrix – the material that is the substrate of heart scaffold – can send signals to guide the MCPs into becoming the specialized cells that are needed for proper heart function.”

Finally, the heart had enough cells to power itself and beat on its own (check the embedded video in this article) – a breakthrough moment in science. It still needs a tremendous amount of refining though. For one, as states earlier, it needs to beat a certain rate, and besides the cardiovascular system which needs to be finely regenerated, you need to have a precise density of cardiovascular cells. For human transplants, there’s another challenge. You need to have scaffolds made from other human hearts.  The next move for Yang and his colleagues will be to use as a scaffolding a stripped-down heart from a human cadaver available for research.

“One of our next goals is to see if it’s feasible to make a patch of human heart muscle,” he added. “We could use patches to replace a region damaged by a heart attack. That might be easier to achieve because it won’t require as many cells as a whole human-sized organ would.”

Findings appeared in the journal Nature Communications. source: Pitts Uni

(c) Cell Regeneration

Researchers grow teeth-like structure using stem cells from urine

missing-teethA new study performed by scientists in China has further elevated stem cell research after they successfully grew teeth-like structures using cells derived from an unlikely source: urine. Eventually, they hope that human stem cells could provide the basis for a tooth bud that could be transplanted into the jaw of the patient.

Some of you might find it weird that someone would use cells from urine for organ generation, considering there might be other more interesting sources at hand – previous research showed, however, that it is indeed feasible to generate cells from urine. Also, cells discarded with urea have been made into induced pluripotent stem cells (iPSCs) – a sort of adult stem cells – that can be used to generate just about any type of tissue, from neurons to muscles.

Duanqing Pei and his colleagues from Guangzhou Institutes of Biomedicine and Health used such iPSCs derived from urine to  a tissue culture system that eventually went on to resemble the shape and structure of human teeth. But first the team used chemicals to coax the cultured iPSCs into flat sheets of epithelial cells, which they then mixed with mouse embryonic mesenchymal cells, and transplanted them into mice.

(c) Cell Regeneration

(c) Cell Regeneration

Three weeks later, formations had grown that physically and structurally resembled human teeth that have many of the qualities of human teeth: elasticity, pulp, dentin, and enamel-forming cells. There are some serious drawbacks to their method, however. First off, the success rate is of only 30% and the resulting teeth are about a third as hard as human teeth.

Using human cells instead of mouse cells might help resolve this issues and help researchers finally completely regenerate human teeth for clinical therapy – a lifelong dream for many involves in such work. And if the patient’s own cells were used, the risk of rejection by the body is negated.

The research whose findings were recently published in the journal Cell Regeneration, is the latest in a slew of advances that make use of induced pluripotent stem cells to generate human compatible tissue, bringing regenerative medicine back in the spotlight. For instance, ZME Science recently reported how scientists used iPSCs to grow a liver, functioning blood cells, and even mice from dish-cultured sperm and egg.

For many years stem cells were viewed with somewhat skepticism since they’re so difficult to come by and, of course, the controversy surrounding embryo use. Induced pluripotent stem cells solve the classic drawbacks of stem cells simply by avoid them and can come from readily accessible sources like skin, blood or just about any adult cell in a host body. As you’ve learned, even cells from urine can make due. Furthermore, cells generated by this method cannot be rejected by the human immune system, being derived from the host’s own cellular material.

This laser microscopy image shows iPSC-generated endovascular cells in green, connective tissue cells in blue, and red blood cells in red. (c) PNAS

Scientists create functional blood vessels from adult stem cells

 This laser microscopy image shows iPSC-generated endovascular cells in green, connective tissue cells in blue, and red blood cells in red. (c) PNAS

This laser microscopy image shows iPSC-generated endovascular cells in green, connective tissue cells in blue, and red blood cells in red. (c) PNAS

Researchers at Harvard-affiliated Massachusetts General Hospital (MGH) have successfully grown and inserted functional blood vessels into animal models after they  used vascular precursor cells derived from human induced pluripotent stem cells (iPSCs). These blood vessels lasted for as long as nine months, much longer than any previous attempt, making the Harvard researchers’ efforts seem extremely promising. Patients suffering from damaged blood vessels, like those suffering from type-1 diabetes, could particularly benefit.

“The discovery of ways to bring mature cells back to a ‘stemlike’ state that can differentiate into many different types of tissue has brought enormous potential to the field of cell-based regenerative medicine, but the challenge of deriving functional cells from these iPSCs still remains,” says Rakesh Jain, Andrew Werk Cook Professor of Radiation Oncology (Tumor Biology) at Harvard Medical School (HMS), director of the Steele Laboratory for Tumor Biology at MGH, and co-senior author of the study. “Our team has developed an efficient method to generate vascular precursor cells from human iPSCs and used them to create networks of engineered blood vessels in living mice.”

Indeed, only in recent years has the opportunity of developing stemlike cells from mature cells surfaced, but even so advances so far have been remarkable. This isn’t the first attempt at creating blood vessels from iPSCs, though. Previous studies attempted to generate the types of cells required to build blood vessels — endothelial cells that line vessels and connective tissue cells that provide structural support — however either these didn’t last very long or didn’t work at all once they were inserted inside the animal model.

Generating blood vessels from adult cells

The team of researchers at Harvard had to face this challenge, so they adapted a method originally used to derive endothelial cells from human embryonic stem cells (hESCs).  That method uses a single protein marker to identify vascular progenitors; in this study, the researchers sorted out iPSC-derived cells that expressed not only that protein but also two other protein markers of vascular potential. They then expanded that population using a culture system that team members had previously developed to differentiate endothelial cells from hESCs, and they confirmed that only iPSC-derived cells expressing all three markers generated endothelial cells with the full potential of forming blood vessels.

These cells, in combination with mesenchymal precursors that generate essential structural cells, were then put to the test and inserted onto the surface of  the brains of mice. Within two weeks, the implanted cells had formed networks of blood-perfused vessels that appeared to function as well as adjacent natural vessels and continued to function for as long as 280 days in the living animals. The same combination was also implanted under the skin of mice, however this procedure required five times as many cells to work properly.

The researchers also worked with  iPSCs derived from the cells of patients with type 1diabetes (T1D), which often causes damage to blood vessels. As with cells from healthy individuals, precursors derived from T1D-iPSCs were able to generate functional, long-lasting blood vessels. Key differences in cell generation potential were noticed, however, which require more study.

“The potential applications of iPSC-generated blood vessels are broad — from repairing damaged vessels supplying the heart or brain to preventing the need to amputate limbs because of the vascular complication of diabetes,” says co-lead author Rekha Samuel, formerly of the Steele Laboratory and now at Christian Medical College, in Vellore, India. “But first we need to deal with such challenges as the variability of iPSC lines and the long-term safety issues involved in the use of these cells, which are being addressed by researchers around the world. We also need better ways of engineering the specific type of endothelial cell needed for specific organs and functions.”

The findings were documented in a report published in the journal Proceedings of the National Academy of Sciences(PNAS) Early Edition.

The stem cell 3-d printer Image of 3-D cell printer courtesy of Colin Hattersley

3D printing stem cells could be used one day to ‘manufacture’ organs

We’re only in the early days of 3-D printing, but even now the breakthroughs made using such technology are most impressive like the genuine possibility of printing spare parts in space for the ISS, creating objects of great details on the nanoscale or even artificial muscles made using a 3-D printer. What’s fabulous though is that 3-D printing is developing at an accelerate pace. One day 3-D printers might actually be used to build working human organs saving millions of lives, maybe in a manner similar to how some SciFi movies depict tissue reconstruction.

The stem cell 3-d printer Image of 3-D cell printer courtesy of Colin Hattersley

The stem cell 3-d printer developed by scientists at Heriot-Watt University. (c) Colin Hattersley

The latter idea, though still very far fetched, recently had its foundation laid at the Scotland’s Heriot-Watt University and Roslin Cellab, where researchers there developed a novel technique which allows stem cells to be printed in blobs. Previously, researchers were able to engineer tissue samples combining artificial scaffold-like structures and animal cells, this is a method that is extremely laborious, however. Rather than manually positioning individual cells, using a 3-D printer  one can uniformly and accurately position them to form a desired tissue.

Stem cells, while extremely appealing for their pluripotent ability to morph into any kind of cell, are very hard to print since they are very sensitive to manipulation. The Scottish scientists tackled this issue by developing a sophisticated method that deposit droplets of a consistent size containing living cells through a valve-based printer nozzle that gently dispenses the cells.

The printing system is driven by pneumatic pressure and controlled by the opening and closing of a microvalve. Thus, one can vary the droplet size and rate of dispensing simply by changing the  nozzle diameter, the inlet air pressure or the opening time of the valve.

Still, though these first steps looks extremely promising, do not grow too excited. We are still decades away from developing a system capable of printing organs in 3-D. Organs, unlike muscles for instance, have a highly complex and sophisticated vascular structure that caries nutrients and exits waste, impossible to replicate by today’s technology. Vascular tissue engineering research is already on the works, however, and this aspect too might be taken care of. Make no mistake, it might not happen during our life time.

The method was reported in the journal Biofabrication.

via Scientific American

As cells squeeze through a narrow channel, tiny holes open in their membranes, allowing large molecules such as RNA to pass through. Image: Armon Sharei and Emily Jackson

New method allows large molecules to get squeezed through cell membranes

A group of researchers at MIT have devised a new method for infiltrating cells with large molecules such as nanoparticles or proteins that is a lot more non-intrusive and doesn’t damage the cell. Imaging target cells or growing more stable stem cells might thus be possible with this method.

As cells squeeze through a narrow channel, tiny holes open in their membranes, allowing large molecules such as RNA to pass through. Image: Armon Sharei and Emily Jackson

As cells squeeze through a narrow channel, tiny holes open in their membranes, allowing large molecules such as RNA to pass through.
Image: Armon Sharei and Emily Jackson

Every cell has a membrane, which is put to great use as it protects the cell’s inner environment by regulating what gets in and what gets out. Typically, you don’t want foreign molecules entering your cells, but sometimes you do. Various methods have been employed to breach cell membranes and introduce other bodies, however these tend to be intrusive and sometimes can lead to the damaging and even destruction of the cell.

The MIT method of introducing large molecules in cell is a lot safer and efficient and implies squeezing the cell through a narrow construction just enough for tiny, yet temporary, gaps to surface. Prior to squeezing the cell, large molecules – be it RNA, proteins or nanoparticles – are tasked to float outside cell, such that when the holes pop these slide through the membrane instantly.

Through this technique the MIT researchers were able to deliver reprogramming proteins which turned the target cells into pluripotent stem cells – notoriously difficult to generate efficiently – with a success rate 10 to 100 times better than any other existing method. A simply massive advancement. Also, they’ve also tested the method with other large molecules like special nanoparticles, like carbon nanotubes or quantum dots, to image cells and thus monitor their activity.

“It’s very useful to be able to get large molecules into cells. We thought it might be interesting if you could have a relatively simple system that could deliver many different compounds,” says Klavs Jensen, the Warren K. Lewis Professor of Chemical Engineering, professor of materials science and engineering, and a senior author of a paper describing the new device in this week’s issue of the Proceedings of the National Academy of Sciences.

The team’s fantastic research builds upon previous work, when Jensen and Robert Langer, the David H. Koch Institute Professor at MIT and also a study lead author, forced molecules into cells as they flowed through a microfluidic device. The process was slow and not very effective, but it was during this time that the researchers learned that if you squeeze a cell just right now, tiny holes will appear – pure windows of opportunity.

Capitalizing on this, the scientists then proceeded to adjust their set-up and devised some rectangular microfluidic chips, no larger than a quarter, fitted with 40 to 70 parallel channels.  Cells are suspended in a solution with the material to be delivered and flowed through the channel at high speed — about one meter per second. Halfway through the channel, the cells pass through a constriction about 30 to 80 percent smaller than the cells’ diameter. The cells don’t suffer any irreparable damage, and they maintain their normal functions after the treatment.

“This appears to be a very broadly applicable approach for loading a diversity of different compounds into a diversity of different cells,” says Mark Prausnitz, a professor of chemical and biomolecular engineering at Georgia Tech, who was not part of the research team. “It’s a really nice example of taking devices from the world of engineering and microelectronics and using them in quite different ways to solve problems in medicine that could have really great impact.”

 

source: MIT

Pluripotent Stem Cells

Massive database of of 1,500 stem cell lines derived from diseased cells set to aid drug development

Pluripotent Stem Cells

The StemBANCC project, developed as a joint effort between the European Union and Europe’s pharmaceutical industry, is set to culture 1,500 pluripotent stem cell lines derived from the cells of diseased individuals like Alzheimer’s patients is currently planned. Using this massive database, researchers will be able to achieve much smoother and faster drug screening process in order to counter these diseases.

The 50 million euros project human-induced pluripotent stem cells as a drug discovery platform to treat the following 8 common diseases: Alzheimer’s disease, Parkinson’s disease, autism, schizophrenia, bipolar disorder, migraine, pain and diabetes.

Stem cells have been hailed as the basis for developing miracle drugs by the media on countless occasions. The project’s aims are not to derive drugs from stem cells, however, but to ease the development of mainstream drugs, that are a lot cheaper, by offering a drug screening platform. It’s one thing to test drugs on mice, and another thing to test them on human cells, more importantly on diseased cells.

For instance skin cells from a Parkinson’s patient can be turned into  pluripotent stem cells that can then be turned into neurons. This would offer researchers an amazing tool. Sure scientists can do this already, but when the project will be live, they could simply order the kind of stem cells they require for their research and be done with it.

Zameel Cader, neurologist at the University of Oxford and a leader on the project, told Nature, “We’re specifically trying to develop a panel of lines across a range of diseases that are important to address. There isn’t another institution that’s doing this at the same scale across the same range of diseases.”

image source

Making brain cells from urine

Some of the human waste we flush out each day could become valuable research material – a potent source of brain cells to analyze, something extremely important for neurodegenerative diseases studies.

The technique, described in Nature Methods doesn’t involve embryonic stem cells, which have serious drawbacks when transplanted such as the risk of developing tumours. Instead, the method uses ordinary cells present in urine, and transforms them into neural progenitor cells — the precursors of brain cells.

Transforming cultured skin and blood cells into induced pluripotent cells (iPS) which can then become any stem cell in the body is no longer a challenge for researchers anymore, but urine is a much more accessible and reliable source. The research was conducted by stem-cell biologist Duanqing Pei and his colleagues at China’s Guangzhou Institutes of Biomedicine and Health, part of the Chinese Academy of Sciences.

The team used etroviruses to insert pluripotency genes into cells — a common technique in cell reprogramming, managing to produce cells that resembled pluripotent stem cells after only 12 days – twice faster than the typical time necessary to produce iPS.

“This could definitely speed things up,” says James Ellis, a medical geneticist at Toronto’s Hospital for Sick Children in Ontario, Canada, who makes patient-specific iPS cells to study autism spectrum disorders.

Pei and his colleagues transferred the cells to a growth medium used for neurons, and they noticed that the cells went on to form functional neurons. But perhaps the biggest advantage is that urine can be collected with ease from nearly any patient – something especially useful when working with children.

“We work on childhood disorders,” he says. “And it’s easier to get a child to give a urine sample than to prick them for blood.”

Via Nature

iPS cells stained for proteins expressed during the cell cycle. (Image by Vaccarino lab)

DNA not the same in every cell of the body, groundbreaking study finds

Popular scientific consensus says that DNA code is identical in every cell of our bodies. A new study from Yale University that could pose extreme far reaching consequences in the field tested a highly controversial hypothesis that claimed genetic variations are widespread through out the body. The researchers found that this claim is true. For instance, 30 percent of skin cells have been found to harbor different DNA.

“We found that humans are made up of a mosaic of cells with different genomes,” said lead author Dr. Flora Vaccarino, the Harris Professor of Child Psychiatry at the Yale Child Study Center. “We saw that 30 percent of skin cells harbor copy number variations (CNV), which are segments of DNA that are deleted or duplicated. Previously it was assumed that these variations only occurred in cases of disease, such as cancer. The mosaic that we’ve seen in the skin could also be found in the blood, in the brain, and in other parts of the human body.”

 iPS cells stained for proteins expressed during the cell cycle. (Image by Vaccarino lab)


iPS cells stained for proteins expressed during the cell cycle. (Image by Vaccarino lab)

A longstanding dogma is that all our cells have the same DNA sequence that governs all bodily functions. The researchers at Yale evaluated a hypothesis that stated during the cell duplication process, DNA may suffer deletions and sequence alterations with potential far reaching consequences on whole groups of genes.

To establish or disprove this theory, however, proved to be a very challenging task. Vaccarino and colleagues grew pluripotent stem cells lines (iPS) – stem cells developed from a mature-differentiated cell – from the inner upper arms of two families.

DNA genetic mosaic

The scientists spent two years studying these iPS lines, comparing them to the original cells. While the DNA in the iPS cell lines was extremely similar to that of the original cells, the scientists observed several deletions or duplications involving thousands of base pairs of DNA. Upon closer investigation, the scientists found that at least half of these differneces pre-existed in small fractions of skin cell.

“In the skin, this mosaicism is extensive and at least 30 percent of skin cells harbor different deletion or duplication of DNA, each found in a small percentage of cells,” said Vaccarino. “The observation of somatic mosaicism has far-reaching consequences for genetic analyses, which currently use only blood samples. When we look at the blood DNA, it’s not exactly reflecting the DNA of other tissues such as the brain. There could be mutations that we’re missing.”

“These findings are shaping our future studies, and we’re doing more studies of the developing brains of animals and humans to see if this variation exists there as well,” Vaccarino added.

The findings were documented in the journal Nature.

source: Yale

Adult mice grown from eggs and sperm induced by pluripotent stem cells. (c) Mitinori Saitou and Katsuhiko Hayashi

Scientists grow mice from dish-cultured sperm and egg

Adult mice grown from eggs and sperm induced by pluripotent stem cells. (c) Mitinori Saitou and Katsuhiko Hayashi

Adult mice grown from eggs and sperm induced by pluripotent stem cells. (c) Mitinori Saitou and Katsuhiko Hayashi

Kyoto University researchers have produced normal, healthy mouse pups after inseminating a foster mother with eggs and sperm derived from stem cells, exclusively grown in a petri dish. This remarkable accomplishment came after last year scientists produced mouse pups from stem cell grown sperm. Their research might lead to the development of novel techniques through which infertile couples may conceive.

“This is a significant achievement that I believe will have a sustained and long-lasting impact on the field of reproductive cell biology and genetics,” says Amander Clark, a stem cell biologist at University of California, Los Angeles.

The team of researchers, lead by Mitinori Saitou, first collected both embryonic stem cells (ES) and  induced pluripotent stem cells (iPS). The latter are cell sampled from adult tissue, reprogrammed to act like stem cells. These were cultured  in a cocktail of proteins to produce primordial germ cell-like cells, such that the researchers might obtain oocytes – pre-eggs. The primordial cells were then mixed with fetal ovarian cells, forming reconstituted ovaries that they then grafted onto natural ovaries in living mice.

The scientists found that after four weeks and three days the  primordial germ cell-like cells had developed into oocytes. These were fertilized resulting in embryos which were implanted in surrogate mothers. Three weeks later the first pups were born – healthy and normal.

The Japanese researchers conclude that their “culture system serves as a robust foundation for the investigation of key properties of female germ cells, including the acquisition of totipotency, and for the reconstitution of whole female germ-cell development in vitro.”

The study, published in the journal Science, says that the findings might form the basis for a new technique which might allow for treating infertility.

“This study has provided the critical proof of principle that oocytes can be generated from induced pluripotent stem cells,”

via Wired

A scheme of the generation of induced pluripotent stern (IPS) cells

Scientists grow rudimentary human liver in a dish

A scheme of the generation of induced pluripotent stern (IPS) cells

A scheme of the generation of induced pluripotent stern (IPS) cells

In an extraordinary feat of science, Japanese scientists have used induced stem cells to grow into a liver-like tissue in a dish. The researchers have a long way ahead of them before they can grow livers safe for human transplants, which is the main goal, however even at its current stage, the tissue grown by the researchers can satisfy rudimentary metabolic functions and marks a breakthrough in the field.

“It blew my mind,” said George Daley, director of the stem-cell transplantation programme at the Boston Children’s Hospital in Massachusetts, who chaired the session. “It sounds like a genuine advance,” says Stuart Forbes, who studies liver regeneration at the University of Edinburgh, UK

In the US alone, there are 17,000 people currently on the official national waiting list for a liver transplant. Many patients are in a critical situation and are in dire need of a transplant; considering the median waiting period if of one year, for most it’s too late. Lab grown organs, which are stable and compatible with the patient, would save thousands of lives each year.

The work was presented by Takanori Takebe, a stem-cell biologist at Yokohama City University in Japan, at the annual meeting of the International Society for Stem Cell Research in Yokohama last week.

Takebe and his team re-programmed human skin cells to an embryo-like state to create induced pluripotent stem cells (iPS). These human pluripotent stem cells are crucial for the development of regenerative medicine, which can basically allow for growing a whole new heart or liver, since they can be converted into any cell type in the body. The stem cells were then placed in a dish and after nine days, analysis showed that they contained a biochemical marker of maturing liver cells, called hepatocytes.

Next, Takebe added two more types of cell known to help to recreate organ-like function in animals: endothelial cells, which line blood vessels, taken from an umbilical cord; and mesenchymal cells, which can differentiate into bone, cartilage or fat, taken from bone marrow. In a mere 5 days,  the cells assembled into a 5-millimetre-long, three-dimensional tissue that the researchers labelled a liver bud — a extremely rudimentary liver tissue, of the organ’s early development stage.

The tissue has blood vessels that proved functional when it was transplanted under the skin of a mouse. Genetic tests show that the tissue expresses many of the genes expressed in real liver, and tests on mice which had the tissue transplanted showed that it was able to metabolize some drugs that human livers metabolize but mouse livers normally cannot.

The team claims that its work is “the first report demonstrating the creation of a human functional organ with vascular networks from pluripotent stem cells”.

Takebe and his team’s work is definitely groundbreaking in their findings, however there is still much more that awaits to be studied and experimented before a fully functional stem cell liver can be grown. For this extremely rudimentary liver tissue, the scientists needed over a year and hundreds of trials to properly time the addition of the other two cell types. In the meantime,  the scientists hope that his liver bud could be useful for toxicity testing in drug screening, for which bile ducts are not needed.

The findings, so far, are expected to be published in the journal Nature soon.

source