Three New Clinical Trials Examine Bone Marrow-Based Stem Cells To Treat Heart Failure


In April of 2013, the results of three clinical trials that examined the effects of bone marrow-derived stem cell treatments in patients with acute myocardial infarction (translation – a recent heart attack) or chronic heart failure. These trials were the SWISS-AMI trial, the CELLWAVE trial, and the C-CURE trial.

The SWISS-AMI trial (Circulation. 2013;127:1968-1979), which stands for the Swiss Multicenter Intracoronary Stem Cells Study in Acute Myocardial Infarction trial, was designed to examine the optimal time of stem cell administration at 2 different time points: early or 5 to 7 days versus late or 3 to 4 weeks after a heart attack. This trial is an extension of the large REPAIR-AMI, which showed that patients who tended to receive bone marrow stem cell treatments later rather than earlier had more pronounced therapeutic effects from the stem cell treatments.

SWISS-AMI examined 60 patients who received standard cardiological care after a heart attack, 58 who received bone marrow stem cells 5-7 days after a heart attack, and 49 patients who received bone marrow stem cells 3-4 weeks after their heart attacks. All stem cells were delivered through the coronary arteries by means of the same technology used to deliver a stent.

When the heart function of all three groups were analyzed, no significant differences between the three groups were observed. Those who received stem cell 5-7 days after a heart attack showed a 1.8% increase in their ejection fractions (the percentage of blood that is ejected from the ventricle with each beat) versus an average decrease of 0.4% in those who received standard care, and a 0.8% increase in those who received their stem cells 3-4 weeks after a heart attack. If these results sound underwhelming it is because they are. The standard deviations of each group so massive that these three groups essentially overlap each other. The differences are not significant from a statistical perspective. Thus the results of this study were definitely negative.

The second study, CELLWAVE (JAMA, April 17, 2013—Vol 309, No. 15, 1622-1631), was a double-blinded, placebo-controlled study conducted among heart attack patients between 2005 and 2011 at Goethe University Frankfurt, Germany. In this study, the damaged area of heart was pretreated with low-energy ultrasound shock waves, after which patients in each group were treated with either low dose stem cells, high-dose stem cells, or placebo. Patients also received either shock wave treatment or placebo shock wave treatment. Thus this was a very well-controlled study. Stem cells were administered through the coronary arteries, just as in the case of the SWISS-AMI study.

The results were clearly positive in this study. The stem cell + shock wave treatment groups showed definite increases in heart function above the placebo groups, and showed fewer adverse effects. The shock wave treatments seem to prime the heart tissue to receive the stem cells. The shock waves induce the release of cardiac stromal-derived factor-1, which is a potent chemoattractor of stem cells.  This is an intriguing procedure that deserves more study.

The third study, C-CURE, is definitely the most interesting of the three (Bartunek et al. JACC Vol. 61, No. 23, June 11, 2013:2329–38). In this trial, mesenchymal stromal cells (MSCs) were isolated from bone marrow and primed with a cocktail of chemicals that pushed the stem cells towards a heart muscle fate. Then the cells were transplanted into the heart by direct injection into the heart muscle as guided by NOGA three-dimensional imaging of the heart.

After initially screening 320 patients with chronic heart failure, 15 were treated with standard care and the other 32 received the stem cell treatment. After a two-year follow-up, the results were remarkable: those who received the stem cell treatment showed an average 7% increase in ejection fraction versus 0.2% for receiving standard care, an almost 25 milliliter reduction in end systolic volume (measures degree of dilation of ventricle – not a good thing and the fact that it decreased is a very good thing) versus a 9 milliliter decrease for those receiving standard care, and were able to walk 62 meters further in 6 minutes as opposed to standard care group who walked 18 meters less in 6 minutes.

While these studies do not provide definitive answers to the bone marrow/heart treatment debate, they do extend the debate. Clearly bone marrow stem cells help some patients and do not help others. The difference between these two groups of patients continues to elude researchers. Also, how the bone marrow is processed is definitely important. When the cells are administered also seems to be important, but the exact time slot is not clear in human patients. It is also possible that some patients have poor quality bone marrow in the first place, and might be better served by allogeneic (someone else’s stem cells) treatments rather than autologous (the patient’s own stem cells) stem cell treatments.

Also, stem cell treatments for heart patients will probably need to be more sophisticated if they are to provide greater levels of healing. Heart muscle cells are required, but so are blood vessels to feed the new heart muscle. If mesenchymal stem cells work by activating resident heart stem cells, then maybe mesenchymal transplants should be accompanied by endothelial progenitor cell transplants (CD117+, CD45+ CD31+ cells from bone marrow) to provide the blood vessels necessary to replace the clogged blood vessels and the new heart muscle that is grown.

Prostaglandin E Switches Endoderm Cells From Pancreas to Liver


The gastrointestinal tract initially forms as a tube inside the embryo. Accessory digestive organs sprout from this tube in response to inductive signals from the surrounding mesoderm. Both the pancreas and the liver form at about the same time (4th week after fertilization) and at about the same place in the embryonic gut (the junction between the foregut and the midgut).

Pancreatic development

The pancreas forms as ventral and dorsal outgrowths that eventually fuse together when the gut rotates. The liver forms from the “hepatic diverticulum” that grows from the gut about 23-26 days after fertilization. These liver bud cells work with surrounding tissues to form the liver.

Liver development

What determines whether an endodermal cell becomes a liver or pancreatic precursor cell?

Wolfram Goessling and Trista North from the Harvard Stem Cell Institute (HSCI) have identified a gradient of the molecule prostaglandin E (PGE) in zebrafish embryos that acts as a liver/pancreas switch.

Postdoctoral researcher Sahar Nissim in the Goessling laboratory has uncovered how PGE toggles endodermal cells between the liver-pancreas fate. Nissim has shown that endodermal cells exposed to more PGE become liver cells and those exposed to less PGE become pancreas. This is the first time that prostaglandins have been reported as the factor that can switch cell identities from one fate to another.

After completing these experiments, HSCI scientists collaborated with colleague Richard Mass to determine if their PGE-mediated cell fate switch also occurred in mammals. Here again, Richard Sherwood from the Mass established that mouse endodermal cells became liver if exposed to PGE and pancreas if exposed to less PGE.  Sherwood also demonstrated that PGE enhanced liver growth and regeneration.

Goessling become interested in PGE in 2005, when a chemical screen identified PGE as an agent that amplified blood stem cell populations in zebrafish embryos. Goessling that transitioned this work to human patients, and a phase 1b clinical trial that uses PGE to increase umbilical cord blood transplants has just been completed.

PGE might be useful for instructing pluripotent human stem cells that have been differentiated into endodermal cells to form completely functional, mature liver cells that can be used to treatment patients with liver disease.

Repopulation of Damaged Livers With Skin-Derived Stem Cells


Patients with severe liver disease must receive a liver transplant. This major procedure requires that the patient survives major surgery and then takes anti-rejection drugs for the rest of their lives. In general, liver transplant patients tend to fair pretty well. The one-year survival rate of liver transplant patients approaches 90% (see O’Mahony and Goss, Texas Heart Institute Journal 2012 39(6): 874-875).

A potentially better way to treat liver failure patients would be to take their own liver cells, convert them into induced pluripotent stem cells (iPSCs), differentiate them into liver cells, and use these liver cells to regenerate the patient’s liver. Such a treatment would contain a patient’s own liver cells and would not require anti-rejection drugs.

Induced pluripotent stem cells or iPSCs are made from genetically-engineered adult cells that have had four specific genes (Oct4, Klf4, Sox2, and c-Myc) introduced into them. As a result of the heightened expression of these genes, some of the adult cells dedifferentiate and are reprogrammed into cells that resemble embryonic stem cells. Normally, this procedure is relatively inefficient, slow, and induces new mutations into the engineered cells. Also, when iPSCs are differentiated into liver cells (hepatocytes), they do not adequately proliferate after differentiation, and they also fail to properly function the way adult hepatocytes do.

New work from laboratories at the University of California, San Francisco (UCSF), has differentiated human hepatocytes by means of a modified technique that bypasses the pluripotency stage. These cells were then used to repopulate mouse livers.

“I really like this paper. It’s a step forward in the field,” said Alejandro Soto-Gutiérrez, assistant professor of pathology at the University of Pittsburgh, who was not involved in the work. “The concept is reprogramming, but with a shortcut, which is really cool.”

Research teams led by Holger Willenbring and Sheng Ding isolated human skin cells called fibroblasts and infected them with engineered viruses that forced the expression of three genes: OCT4, SOX2, and KLF4. These transduced cells were grown in culture in the presence of proteins called growth factors and small molecules in order to induce reprogramming of the cells into the primary embryonic germ layer known as endoderm. In the embryo, the endoderm is the inner-most layer of cells that forms the gastrointestinal tract and its associated structures (liver, pancreas, and so on). Therefore, the differentiation of adult cells into endodermal progenitor cells provides a handy way to form a cell type that readily divides and can differentiate into liver cells.

“We divert the cells on their path to pluripotency,” explained coauthor Holger Willenbring, associate professor of surgery at UCSF. “We still take advantage of what is intrinsic to reprogramming, that the cells are becoming very plastic; they’ve become flexible in what kind of cell type they can be directed towards.”

The authors called these cells induced multipotent progenitor cells (iMPCs). The iMPCs were easily differentiated into endodermal progenitor cells (iMPC-EPCs). These iMPC-EPCs were grown in culture with a cocktail of small molecules and growth factors to increase iMPC-EPC colony size while concomitantly maintain them in an endodermal state. Afterwards, Willenbring and others cultured these cells with factors and small molecules known to promote liver cell differentiation. When these iMPC-Hepatocytes (Heps) were transplanted into mice with damaged livers, the iMPC-Hep cells continued to divide at least nine months after transplantation. Furthermore, the transplanted cells matured and displayed gene expression profiles very similar to that of typical adult hepatocytes. Transplantation of iMPC-Heps also improved the survival of a mouse model of chronic liver failure about as well as did transplantation of adult hepatocytes.

“It is a breakthrough for us because it’s the first time that we’ve seen a cell that can actually repopulate a mouse’s liver,” said Willenbring. Willenbring strongly suspects that iMPCs are better able to repopulate the liver because the derivation of iMPC—rather than an iPSC—eliminates some steps along the path to generating hepatocytes. These iMPCs also possess the ability to proliferate in culture to generate sufficient quantities of cells for therapeutic purposes and, additionally, can functionally mature while retaining that proliferative ability to proliferate. Both of these features are important prerequisites for therapeutic applications, according to Willenbring.

Before this technique can enter clinical trials, more work must be done. For example: “The key to all of this is trying to generate cells that are identical to adult liver cells,” said Stephen Duncan, a professor of cell biology at Medical College of Wisconsin, who was not involved in the study. “You really need these cells to take on all of the functions of a normal liver cell.” Duncan explained that liver cells taken directly from a human adult might be able to repopulate the liver in this same mouse model at levels close to 90 percent.

Willenbring and his colleagues observed repopulation levels of 2 percent by iMPC-Heps, which is substantially better than the 0.05 percent repopulation typically accomplished by hepatocytes derived from iPSCs or embryonic stem cells. However: “As good as this is, the field will need greater levels of expansion,” said Ken Zaret of the Institute for Regenerative Medicine at the University of Pennsylvania, who did not participate in the work. “But the question is: What is limiting the proliferative capacity of the cells?”

Zaret explained that it is not yet clear whether some aspect of how the cells were programmed that differed from how they normally develop could have an impact on how well the population expands after transplantation. “There still is a ways to go [sic],” he said, “but [the authors] were able to show much better long-term repopulation with human cells in the mouse model than other groups have.”

See S. Zhu et al., “Mouse liver repopulation with hepatocytes generated from human fibroblasts,” Nature, doi:10.1038/nature13020, 2014.

Sweat Glands Are A Source of Stem Cells for Wound Healing


Stem Cells from human sweat glands serve as a remarkable source for wound healing treatments according to a laboratory in Lübeck, Germany.

Professor Charli Kruse, who serves as the head of the Fraunhofer Research Institute for Marine Biotechnology EMB, Lübeck, Germany, and his colleagues isolated cultured pancreatic cells in the course of their research to look into the function of a protein called Vigilin. When the pancreatic cells were grown in culture, they produced, in addition to other pancreatic cells, nerve and muscle cells. Thus the pancreas contains a stem cell population that can differentiate into different cell types.

Kruse and his group decided to investigate other glands contained a similar stem cell population that could differentiate into other cell types.

Kruse explained: “We worked our way outward from the internal organs until we got to the skin and the sweat glands. Again, this yielded the same result: a Petri dish full of stem cells.”

Up to this point, sweat glands have not received much attention from researchers. Mice and rats only have sweat glands on their paws, which makes them rather inaccessible. Human beings, on the other hand, have up to three million sweat glands, predominantly on the soles of out feet, palms of the hand, armpits, and forehead.

Ideally, a patient could have stem cells taken from her own body to heal an injury, wound, or burn, Getting to these endogenous stem cell populations, however, represents a challenge, since it requires bone marrow biopsies or aspirations, liposuction, or some other invasive procedure.

Sweat glands, however, are significantly easier to find, and a short inpatient visit to your dermatologist that extracts three millimeters of underarm skin could provide enough stem cells to grow in culture for treatments.

Stem cells from sweat glands have the capacity to aid wound healing. Kruse and his group used sweat gland-based stem cells in laboratory animals. The Kruse group used skin biopsies from human volunteers and separated out the sweat gland tissues under a dissecting scope. Then the sweat gland stem cells were grown in culture and induced to differentiate into a whole host of distinct cell types.

Then Kruse’s team grew these sweat gland stem cells in a skin-like substrate that were applied to wounds on the backs of laboratory animals. Those animals that had received stem cell applications healed faster than those that received no stem cells.

If the stem cells were applied to the mice with the artificial substrate, the cells moved into the bloodstream and migrated away from the site of the injury. In order to help heal the wound the cells had to integrate into the skin and participate in the healing process.

“Not only are stem cells from sweat glands easy to cultivate, they are extremely versatile, too,” said Kruse.

Kruse and his team are already in the process of testing a treatment for macular degeneration using sweat gland-based stem cells. “In the long-term, we could possibly set up a cell bank for young people to store stem cells from their own sweat glands/ They would then be available for use should the person need new cells, following an illness,l perhaps, or in the event of an accident,” Kruse said.

Reversing Lung Diseases By Directing Stem Cell Differentiation


Lung diseases can scar the respiratory tissues necessary for oxygen exchange. Without proper oxygen exchange, our cells lack the means to make the energy they so desperately need, and they begin to shut down or even die. Lung diseases such as asthma, emphysema, chronic obstructive pulmonary disease and others can permanently diminish lung capacity, life expectancy and activity levels.

Fortunately, a preclinical study in laboratory animals has suggested a new strategy for treating lung diseases. Carla Kim and Joo-Hyeon Lee of the Stem Cell Research Program at Boston Children’s have described a new lung-specific pathway that is activated by lung injury and directs a resident stem cell population in the lung to proliferate and differentiate into lung-specific cell types.

When Kim and Lee enhanced this pathway in mice, they observed increase production of the cells that line the alveolar sacs where gas exchange occurs. Alveolar cells are irreversibly damaged in emphysema and pulmonary fibrosis.

Inhibition of this same pathway increased stem cell-mediated production of airway epithelial cells, which line the passages that conduct air to the alveolar sacs and are damaged in asthma and bronchiolitis obliterans.

For their experiments, Kim and Lee used a novel culture system called a 3D culture system that mimics the milieu of the lung. This culture system showed that a single bronchioalveolar stem cell could differentiate into both alveolar and bronchiolar epithelial cells. By adding a protein called TSP-1 (thrombospondin-1), the stem cells differentiated into alveolar cells.

Next, Kim and Lee utilized a mouse model of pulmonary fibrosis. However, when they cultured the small endothelial cells that line the many small blood vessels in the lung, which naturally produce TSP-1, and directly injected the culture fluid of these cells into the mice, the noticed these injections reverse the lung damage.

When they used lung endothelial cells that do not produce TSP-1 in 3D cultures, lung-specific stem cells produce more airway cells. in mice that were engineered to not express TSP-1, airway repair was enhanced after lung injury.

Lung Stem Cell Repair of Lung Damage

Lee explained his results in this way: “When the lung cells are injured, there seems to be a cross talk between the damaged cells, the lung endothelial cells and the stem cells.”

Kim added: “We think that lung endothelial cells produce a lot of repair factors besides TSP-1. We want to find all these molecules, which could provide additional therapeutic targets.”

Even though this work is preclinical in nature, it represents a remarkable way to address the lung damage that debilitates so many people. Hopefully this work is easily translatable to human patients and clinical trials will be in the future. Before that, more confirmation of the role of TSP-1 is required.

A Molecular Switch that Determines Stem Cell Or Neuron


A University of California, San Diego School of Medicine research team has provided new information about a well-known protein that provides the switch for cells to become neurons. This protein is part of a regulatory circuit that can push an immature neural cell to become a functional neuron.

Postdoctoral fellow Chih-Hong Lou and his colleagues worked with principal investigator Miles F. Wilkinson, who is a professor in the Department of Reproductive Medicine, and is also a member of the UC San Diego Institute for Genomic Medicine. These data were published in the February 13 online issue of the journal Cell Reports. These data may also elucidate a still poorly understood process – neuron specification – and might significantly accelerate the development of new therapies for specific neurological disorders, such as autism and schizophrenia.

Wilkinson, Lou and others discovered that the conversion of immature cells to neurons is controlled by a protein called UPF1. UPF1 works in a pathway called the “nonsense-mediated RNA decay” or NMD pathway. The NMD pathway provides a quality control mechanism that eliminates faulty messenger RNA (mRNA) molecules.

mRNA molecules are synthesized from DNA in the nucleus of cells and are exported to the cytoplasm where they are translated by ribosomes into protein. All proteins are encoded by stretches of DNA known as genes and the synthesis of an RNA copy of this stretch of DNA is called transcription. After the transcription of a messenger RNA molecule, is goes to the cytoplasm and is used as the template for the synthesis of a specific protein. Occasionally, mistakes are made in the transcription of mRNAs, and such aberrant mRNAs will either be translated into junk protein, or are so damaged that they cannot be recognized by ribosomes. Such junk mRNAs will gum up the protein synthesis machinery, but cells have the NMD pathway that degrades junk mRNAs to prevent the collapse of the protein synthesis machinery.

UPF1 mechanism

A second function for the NMD pathway is to degrade a specific group of normal mRNAs to prevent the production of particular proteins. This NMD function is physiologically important, but until now it had not been clear why it is important.

Wilkinson and others have discovered that UPF1, in combination with a particular class of microRNAs, acts as a molecular switch to determine when immature (non-functional) neural cells take the plunge and differentiate into non-dividing (functional) neurons. In particular, UPF1 directs the degradation of a specific mRNA that encodes for a protein in the TGF-beta signaling pathway, which promotes neural differentiation. The destruction of this mRNA prevents the proper functioning of the TGF-beta signaling pathway and neural differentiation fails to occur. Therefore, Wilkinson, Lou and co-workers identified, for the first time, a molecular pathway in which NMD drives a normal biological response.

NMD also promotes the decay of mRNAs that encode proliferation inhibitors, which Wilkinson said might explain why NMD stimulates the proliferative state characteristic of stem cells. There are many potential clinical ramifications for these findings,” Wilkinson said. “One is that by promoting the stem-like state, NMD may be useful for reprogramming differentiated cells into stem cells more efficiently.

Wilkinson continued: “Another implication follows from the finding that NMD is vital to the normal development of the brain in diverse species, including humans. Humans with deficiencies in NMD have intellectual disability and often also have schizophrenia and autism. Therapies to enhance NMD in affected individuals could be useful in restoring the correct balance of stem cells and differentiated neurons and thereby help restore normal brain function.”

Co-authors on this paper include Ada Shao, Eleen Y. Shum, Josh L. Espinoza and Rachid Karam, from the UCSD Department of Reproductive Medicine; and Lulu Huang, from Isis Pharmaceuticals.

Funding for this research came, in part, from National Institutes of Health (grant GM-58595) and the California Institute for Regenerative Medicine.

Results of STAP Cell Paper Questioned


Reports of Stimulus-Triggered Acquisition of Pluripotency or STAP cells has rocked the stem cell world. If adult cells can be converted into pluripotent stem cells so easily, then perhaps personalized, custom stem cells for each patient are just around the corner.

However, the RIKEN institute, which was heavily involved in the research that brought STAP cells to the world has now opened an investigation into this research, since leading scientists have voiced discrepancies about some of the figures in the paper and others have failed to reproduce the results in the paper.

Last week, Friday (February 14, 2014, spokespersons for the RIKEN centre, which is in Kobe, Japan, announced that the institute is looking into alleged irregularities in the work of biologist Haruko Obokata, who works at the institution. Obokata was the lead author listed on two papers that were published in the international journal Nature. These papers (Obokata, H. et al. Nature 505, 641–647 (2014), and Obokata, H. et al. Nature 505, 676–680 (2014) described a rather simple protocol for deriving pluripotent stem cells from adult mouse cells by exposing them to acidic conditions, other types of stresses such as physical pressure on cell membranes. The cells, according to these two publications, had virtually all the characteristics of mouse embryonic stem cells, but had the added ability to form placental structures, which is an ability that embryonic stem cells do not have. The investigation initiated by the RIKEN centre comes at the behest of scientists who have noticed that some of the images used in these papers might have been duplicated from other papers. Also, several scientists have notes that they have been unable, to date, to replicate her results.

These concerns came to a head last week when the science blog PubPeer, and others, noted some problems in these two Nature papers and in an earlier paper from 2011. Obokata is also the first author of this 2011 paper (Obokata, H. et al. Tissue Eng. Part A 17, 607–15 (2011), and this paper contains a figure that seems to have been used for one of the figures in the 2014 paper. Also, there is another figure duplication.

Harvard Medical School anesthesiologist Charles Vacanti who was the corresponding author of one of the Nature papers has said that has learned last week about a data mix up in the paper and has contacted the journal to request a correction. “It certainly appears to have been an honest mistake [that] did not affect any of the data, the conclusions or any other component of the paper,” says Vacanti. Note that Vacanti is a co-author on both papers and a corresponding author on one of them.

In the other paper, Obokata serves as the corresponding author and this paper contains an image of two placentas that appear to be very similar. Teruhiko Wakayama works at Yamanashi University in Yamanashi prefecture, and he is a co-author on both of these papers. According to Wakayama, he sent more than a hundred images to Obokata and suggests that there was confusion over which to use. He says he is now looking into the problem.

Additionally, ten prominent stem-cell scientists have been unable to repeat Obokata’s results. One particular blog listed eight failures from scientists in the field. However, most of those attempts did not use the same types of cells that Obokata used.

Some scientists think that this could simply be a case of experienced scientists working with a system that they know very well and can manipulate easily, unlike outsiders to this same laboratory. For example, Qi Zhou, a cloning expert at the Institute of Zoology in Beijing, who says most of his mouse cells died after treatment with acid, says that “setting up the system is tricky; as an easy experiment in an experienced lab can be extremely difficult to others, I won’t comment on the authenticity of the work only based on the reproducibility of the technique in my lab,” says Zhou.

However, others are more deeply concerned. For example, Jacob Hanna, a stem-cell biologist at the Weizmann Institute of Science in Rehovot, Israel, however, says “we should all be cautious not to persecute novel findings” but that he is “extremely concerned and sceptical”. He plans to try for about two months before giving up.

It could be that the protocol is far more complicated that thought. For example, even Wakayama has been having trouble reproducing the results. To be sure, Wakayama and a student of his were able to replicate the experiment independently before publication, but only after being coached by Obokata. But since he moved to Yamanashi, he has had no luck. “It looks like an easy technique — just add acid — but it’s not that easy,” he says.

Wakayama says that his own success in replicating Obokata’s results has convinced him that her technique works. “I did it and found it myself,” he says. “I know the results are absolutely true.”

Clearly one way to clear this up is for the authors of this groundbreaking paper to publish a detailed protocol on how to make STAP cells. This should clear up any problems with the papers. Vacanti says he has had no problem repeating the experiment and says he will let Obokata supply the protocol “to avoid any potential for variation that could lead to confusion”.

The journal Nature has said that there are aware of the problems with the papers and looking into the matter.

For now, that’s where the issue sits. Frustrating I know, but until we know more we will have to just “wait and see.”

Taiwanese Group Identifies Stem Cell-Based Drug to Rejuvenate Aged Hearts


A southern Taiwan-based National Cheng Kung University research team led by Patrick Ching-Ho Hsieh has discovered that a molecule called prostaglandin E2 can regenerate aged hearts in rodents.

This discovery provides a useful new perspective on heart regeneration and presents an effective option for heart disease patients other than heart transplant.

According to Hsieh, congestive heart disease and other cardiovascular diseases are a leading cause of morbidity and mortality throughout the world. There are some six million patients with congestive heart failure in the US alone and some 400,000 in Taiwan. Despite intensive drug, surgical and other medical interventions, 80 percent of all heart patients die within 8 years of diagnosis.

Even though several experiments and clinical trials have established that heart regeneration can take place, the means by which the heart regenerates is still not completely clear, and there are also no drugs to stimulate heart regeneration by the resident stem cell population in the heart.

Now, after seven years of hard work, Hsieh’s team has identified the critical time period and the essential player that directs heart repair.

Hsieh and his colleagues used genetically engineered mice that Hsieh had developed as a postdoctoral research fellow at Harvard Medical School. By using this transgenic mouse strain, Hsieh and others showed that the self-repair process of the heart begins 7 days after injury and peaks at 10 days after injury.

The “director” of this self-repair process is the molecule PGE2. PGE2 regulates heart-specific stem cell activities.

PGE2

“More importantly, both young and old mice have significant improvements for cardiac remodeling if you treat both of them [with] PGE2,” said Hsieh.

Hsieh’s team also established that PGE2 decreases expression of a gene associated with aging, TGF-beta1. PGE2 also rejuvenates the micro-environment of the aged cells, according to Hsieh.

Restoring Muscle Strength in Aging Muscle


Unfortunately, muscle tone and strength decrease as we age. You can work out at the gym all you want. Eventually the relentless march and deterioration of age catches up with even the most avid athlete. However, a Stanford University group believes that they might have discovered why this happens and new cell targets to help reverse it.

According to Helen Blau (the doyen of muscle research), over time, stem cells that help repair damaged muscle cells after injury are less able to do so. This explains why regaining strength and recovering from a muscle injury gets more difficult with age. Blau and her team published their results in the journal Nature Medicine.

Fortunately, Blau’s study also suggests a way to make older muscle stem cells function more like younger ones. The caveat is that research in mice often doesn’t translate to humans. Therefore more work is necessary in order to determine if this technique could ever be used in people.

“In the past, it’s been thought that muscle stem cells themselves don’t change with age, and that any loss of function is primarily due to external factors in the cells’ environment,” study senior author Helen Blau, director of Stanford’s Baxter Laboratory for Stem Cell Biology, said in a university news release.

“However, when we isolated stem cells from older mice, we found that they exhibit profound changes with age,” said Blau, a professor of microbiology and immunology at the university. “Two-thirds of the cells are dysfunctional when compared to those from younger mice, and the defect persists even when transplanted into young muscles.”

The research also revealed, however, that there is a defect specific to old muscle stem cells that can be corrected, which allowed scientists to rejuvenate these stem cells.

“Most exciting is that we also discovered a way to overcome the defect,” Blau said. “As a result, we have a new therapeutic target that could one day be used to help elderly human patients repair muscle damage.”

The muscle stem cells in 2-year-old mice are the equivalent of those found in 80-years-old humans. In the course of their study, Blau and her team found that many muscle stem cells from these mice had increased activity in a certain biological pathway (p38α and p38β mitogen-activated kinase pathways, for those who are interested) that inhibits the production of the stem cells.

Drugs that block this pathway in old stem cells, however, allowed the aged stem cells to make a larger number of new cells that could effectively repair muscle damage.

According to Blau: “In mice, we can take cells from an old animal, treat them for seven days — during which time their numbers expand as much as 60-fold — and then return them to injured muscles in old animals to facilitate their repair.”

Once the mice received their rejuvenated muscle stem cells, the researchers tested their muscle strength with assistance from co-author Scott Delp, a professor in the School of Engineering, who has developed a way to measure muscle strength in animals that underwent stem cell therapy for muscle injuries.

Study lead author Benjamin Cosgrove, a postdoctoral scholar at the university, said: “We were able to show that transplantation of the old, treated muscle stem cell population repaired the damage and restored strength to injured muscles of old mice. Two months after transplantation, these muscles exhibited forces equivalent to young, uninjured muscles. This was the most encouraging finding of all.”

The study’s authors said they plan to continue their research to determine if people could benefit from this technique.

“If we could isolate the stem cells from an elderly person, expose them in culture to the proper conditions to rejuvenate them and transfer them back into a site of muscle injury, we may be able to use the person’s own cells to aid recovery from trauma or to prevent localized muscle atrophy and weakness due to broken bones,” Blau said.

“This really opens a whole new avenue to enhance the repair of specific muscles in the elderly, especially after an injury,” she said. “Our data pave the way for such a stem cell therapy.”

Ending the Reliance on Feeder Cells for Stem Cell Growth


A new study, published today in the journal Applied Materials & Interfaces reports the discovery of a new method for growing human embryonic stem cells that does not depend on feeder cells from human or animal cells.

Traditionally, embryonic stem cells are cultivated with the help of feeder cells derived from animals. Feeder cells secrete a host of growth factors and other signaling molecules that prevent the embryonic stem cells from differentiating and maintain their pluripotency. However, the use of animal products in the production of human cells lines rules out their use in the treatment of humans, since they can become contaminated with animal proteins that will cause rejection by the immune system or animal viruses that can infect the patient and cause significant disease.

The team of scientists led by the University of Surrey and in collaboration with Professor Peter Donovan at the University of California have developed a scaffold of carbon nanotubes upon which human stem cells can be grown into a variety of tissues. These nanotube networks mimic the surface of the body’s natural support cells and act as scaffolding for stem cells to grow on. Even cultured cells that have previously relied on feeder cells can now be grown safely in the laboratory, which paves the way for revolutionary steps in replacing tissue after injury or disease.

Dr Alan Dalton, senior lecturer from the Department of Physics at the University of Surrey said: “While carbon nanotubes have been used in the field of biomedicine for some time, their use in human stem cell research has not previously been explored successfully.”

“Synthetic stem cell scaffolding has the potential to change the lives of thousands of people, suffering from diseases such as Parkinson’s, diabetes and heart disease, as well as vision and hearing loss. It could lead to cheaper transplant treatments and could potentially one day allow us to produce whole human organs without the need for donors.”

I’m on Life Report Podcast


Josh Brahm runs the Life Report podcast and is one of the nicest guys on the planet. Josh invited me to his podcast at the end of last year to talk about my book and stem cell research in general.  The editing of that exchange has become available.

The interview is here, and the bonus discussion is here. Josh is a very good interviewer.  I think you’ll enjoy it.

Histones Might Hold the Key to the Generation of Totipotent Stem Cells


Reprogramming adult cells into pluripotent stem cells remains a major challenge to stem cell research. The process remains relatively inefficient and slow and a great deal of effort has been expended to improve the speed, efficiency and safety of the reprogramming procedure.

Researchers from RIKEN in Japan have reported one piece of the reprogramming puzzle that can increase the efficiency of reprogramming. Shunsuke Ishii and his colleagues from RIKEN Tsukuba Institute in Ibaraki, Japan have identified two variant histone proteins that dramatically enhance the efficiency of induced pluripotent stem cell (iPS cell) derivation. These proteins might be the key to generating iPS cells.

Terminally-differentiated adult cells can be reprogrammed into a stem-like pluripotent state either by artificially inducing the expression of four factors called the Yamanaka factors, or as recently shown by shocking them with sublethal stress, such as low pH or pressure. However, attempts to create totipotent stem cells capable of giving rise to a fully formed organism, from differentiated cells, have failed.  However, a paper recently published in the journal Nature has shown that STAP or stimulus-triggered acquisition of pluripotency cells from mouse cells have the capacity to form placenta in culture and therefore, are totipotent.

The study by Shunsuke Ishii and his RIKEN colleagues, which was published in the journal Cell Stem Cell, attempted to identify molecules in mammalian oocytes (eggs) that induce the complete reprograming of the genome and lead to the generation of totipotent embryonic stem cells. This is exactly what happens during normal fertilization, and during cloning by means of the technique known as Somatic-Cell Nuclear Transfer (SCNT). SCNT has been used successfully to clone various species of mammals, but the technique has serious limitations and its use on human cells has been controversial for ethical reasons.

Ishii’s research group focused on two histone variants named TH2A and TH2B, which are known to be specific to the testes where they bind tightly to DNA and influence gene expression.

Histones are proteins that bind to DNA non-specifically and act as little spool around which the DNA winds.  These little wound spools of DNA then assemble into spirals that form thread-like structures.  These threads are then looped around a protein scaffold to form the basic structure of a chromosome.  This compacted form of DNA is called “chromatin,” and the DNA is compacted some 10,000 to 100,000 times.  Histones are the main arbiters of chromatin formation.  In the figure below, you can see that the “beads on a string” consist of histones with DNA wrapped around them.

DNA_to_Chromatin_Formation

There are five “standard” histone proteins: H1, H2A, H2B, H3, and H4.  H2A, H2B, H3 and H4 form the beads and the H1 histone brings the beads together to for the 30nm solenoid.  Variant histones are different histones that assemble into beads that do not wrap the DNA quite as tightly or wrap it differently than the standard histones.  Two variant histones in particular, TH2A and TH2B, tend to allow DNA wrapped into chromatin to form and more loosely packed structure that allows the expression of particular genes.

When members of Ishii’s laboratory added these two variant histone proteins, TH2A/TH2B, to the Yamanaka cocktail (Oct4, c-Myc, Sox2, and Klf4) to reprogram mouse fibroblasts, they increased the efficiency of iPSC cell generation about twenty-fold and the speed of the process two- to threefold. In fact, TH2A and TH2B function as substitutes for two of the Yamanaka factors (Sox2 and c-Myc).

Ishii and other made knockout mice that lacked the genes that encoded TH2A and TH2B. This work demonstrated that TH2A and TH2B function as a pair, and are highly expressed in oocytes and fertilized eggs. Furthermore, these two proteins are needed for the development of the embryo after fertilization, although their levels decrease as the embryo grows.

Graphical Abstract1 [更新済み]

In early embryos, TH2A and TH2B bind to DNA and induce an open chromatin structure in the paternal genome (the genome of sperm cells), which contributes to its activation after fertilization.

These results indicate that TH2A/TH2B might induce reprogramming by regulating a different set of genes than the Yamanaka factors, and that these genes are involved in the generation of totipotent cells in oocyte-based reprogramming as seen in SCNT.

“We believe that TH2A and TH2B in combination enhance reprogramming because they introduce a process that normally operates in the zygote during fertilization and SCNT, and lead to a form of reprogramming that bears more similarity to oocyte-based reprogramming and SCNT” explains Dr. Ishii.

Human STAP cells – Troubling Possibilities


Soon after the publication of this paper that adult mouse cells could be reprogrammed into embryonic-like stem cells simply by exposing them to acidic environments or other stresses , Charles Vacanti at Harvard Medical School has reported that he and his colleagues have demonstrated that this procedure works with human cells.

STAP cells or stimulus-triggered acquisition of pluripotency cells were derived by Vacanti and his Japanese collaborators last year. These new findings show that adult cells can be reprogrammed into embryonic-like stem cells without genetic engineering. However, this technique worked well in mouse cells, but it was not clear that it would work with human adult cells.

Vacanti and others shocked the world when they published their paper in the journal Nature earlier this year when they announced that adult cells in mice could be reprogrammed through exposure to stresses and proper culture conditions.

Now Vacanti has made good on his promise to test his protocol on human adult cells. In the photo below, provided by Vacanti, human adult cells were reprogrammed to a pluripotent state by exposing them to stresses, followed by growth in culture under specific conditions.

Human STAP cells
Human STAP cells

“If they can do this in human cells, it changes everything, said Robert Lanza of Advanced Cell Technologies in Marlborough, Massachusetts. Such a procedure promises cheaper, faster, and potentially more flexible cells for regenerative medicine, cancer therapy and cell and tissue cloning.

Vacanti and his colleagues say they have taken human fibroblast cells and tested several environmental stressors on them to recreate human STAP cells. He will not presently disclose which particular stressors were applied, he says the resulting cells appear similar in form to the mouse STAP cells. His team is in the process of testing to see just how stem-cell-like these cells are.

According to Vacanti, the human cells took about a week to resemble STAP cells, and formed spherical clusters just like their mouse counterparts. Vacanti and his Harvard colleague Koji Kojima emphasized that these results are only preliminary and further analysis and validation is required.

Bioethical problems potentially emerge with STAP cells despite their obvious potential. The mouse cells that were derived and characterized by Vacanti’s group and his collaborators were capable of making placenta as well as adult cell types. This is different from embryonic stem cells, which can potentially form all adult cell types, but typically do not form placenta. Embryonic stem cells, therefore, are pluripotent, which means that they can form all adult cell types. However, the mouse STAP cells can form all embryonic and adult cell types and are, therefore, totipotent. Mouse STAP cells could form an entirely new mouse. While it is now clear if human STAP cells, if they in fact exist, have this capability, but if they do, they could potentially lead to human cloning.

Sally Cowley, who heads the James Martin Stem Cell Facility at the University of Oxford, said of Vacanti’s present experiments: “Even if these are STAP cells they may not necessarily have the same potential as mouse ones – they may not have the totipotency – which is one of the most interesting features of the mouse cells.”

However the only cells known to be naturally totipotent are in embryos that have only undergone the first couple of cell divisions immediately after fertilization. According to Cowley, any research that utilizes totipotent cells would have to be under very strict regulatory surveillance. “It would actually be ideal if the human cells could be pluripotent and not totipotent – it would make everyone’s life a lot easier,” she opined.

Cowley continued: “However, the whole idea that adult cells are so plastic is incredibly fascinating,” she says. “Using stem cells has been technically incredibly challenging up to now and if this is feasible in human cells it would make working with them cheaper, faster and technically a lot more feasible.”

This is all true, but Robert Lanza from Advanced Cell Technology in Marlborough, Massachusetts, a scientist with whom I have often deeply disagreed, noted: “The word totipotent brings up all kinds of issues,” says Robert Lanza of Advanced Cell Technology in Marlborough, Massachusetts. “If these cells are truly totipotent, and they are reproducible in humans then they can implant in a uterus and have the potential to be turned into a human being. At that point you’re entering into a right-to-life quagmire”

A quagmire indeed, for Vacanti has already talked about using these STAP cells to clone human embryos. Think of it: the creation of very young human beings just for the purpose of ripping them apart and using their cells for research or medicine. Would we allow this if the embryo were older; say the age of a toddler? No we would rightly condemn it as murder, but because the embryo is very young, that somehow counts against it. This is little more than morally grading the embryo according to astrology.

Therefore, whole Vacanti’s experiments are exciting and novel, they hold chilling possibilities. Lanza is right, and it is doubtful that scientists would show the same deference or sensitivities to the moral exigencies he has shown.

Stem Cells Heal Damaged Cells by Transferring Mitochondria


An Indian team from Delhi, India has identified a protein that increases the transfer of mitochondria from mesenchymal stem cells to lung cells, thus augmenting the healing of lung cells.

Stem cells like mesenchymal stem cells from bone marrow, fat, tendons, liver, skeletal muscle, and so on secrete a host of healing molecules, but they also form bridges to other cells and export their own mitochondria to heal damaged cells. Mitochondria are the structures inside cells that make energy. Damaged cells can have serious energy deficiencies and mitochondrial transfer ameliorates such problems (see Cárdenes N et al, Respiration. 2013;85(4):267-78).

This present work from the laboratory of Anurag Agrawal, who is housed in the Centre of Excellence in Asthma & Lung Disease, at the CSIR‐Institute of Genomics and Integrative Biology in Delhi, India has identified a protein called Miro1 that regulates the transfer of mitochondria to recipient cells.

Mitochondrial transfer has so many distinct benefits that stem cell scientists hope to engineer stem cells to transfer more of their mitochondria to damaged cells, and Miro1 might be a target for such stem cell engineering experiments.

Mitochondrial transfer between stem cells and other cells occurs by means of tunneling nanotubes, which are thread-like structures formed from the plasma membranes of cells that form bridges between different cell types. Under stressful conditions, the number of these nanotubes increases.

In the present study. stem cells engineered to express more Miro1 protein transferred mitochondria more efficiently than control stem cells. When used in mice with damaged lungs and airways, these Miro1-overexpressing cells were therapeutically more effective than control cells.

This study presents the first mechanistic insight into how Mesenchymal Stem Cells (MSC) act as mitochondrial donors during attenuation of lung inflammation and injury. Mitochondrial donation is an essential part of the MSC therapeutic effect in these models and is positively regulated by Miro1 / Rhot1 mitochondrial transport proteins.
This study presents the first mechanistic insight into how Mesenchymal Stem Cells (MSC) act as mitochondrial donors during attenuation of lung inflammation and injury. Mitochondrial donation is an essential part of the MSC therapeutic effect in these models and is positively regulated by Miro1 / Rhot1 mitochondrial transport proteins.

The hope is to use Miro1 manipulations to make better stem cell therapies for human diseases.

To summarize this work:

1. MSCs donate mitochondria to stressed epithelial cells (EC) that have malfunctioning mitochondrial.  Cytoplasmic nanotubular bridges form between the cells and Miro‐1 mediated mitochondrial transfer occurs unidirectionally from MSCs to ECs.

2. Other mesenchymal cells like smooth muscle cells and fibroblasts express Miro1 and can also donate mitochondria to ECs, but with low efficiency. ECs have very low levels of Miro1 and, as a rule, do not donate mitochondria.

3. Enhanced expression of Miro1 in mesenchymal cells increases their mitochondrial donor efficiency.  Conversely, cells lacking Miro1 do not show MSC mediated mitochondrial donation.

4. Miro1‐overexpressing MSCs have enhanced therapeutic effects in three different models of allergic lung inflammation and rat poison-induced lung injury.  Conversely, Miro1‐depleted MSCs lose much of their therapeutic effect.  Miro1 overexpression in MSCs may lead to more effective stem cell therapy.

What Holds Skin Together?


A study by the Spanish National Cancer Research Centre (CNIO) has demonstrated that interactions between skin stem cells maintain the architecture of skin. Skin stem cells are responsible for the constant renewal of the skin, and without the close connections between these cells, skin is unable to protect our bodies from the constant assaults from bacteria, chemicals, ultraviolet radiation, heat, cold, shear forces and so on.

A loss of proper adhesion between skin cells sometimes occurs during particular inflammatory diseases and cancer as well. This simple fact has stimulated interest in skin research.

Mirna Pérez-Moreno, who heads the Epithelial Cellular Biology Group that led this study, said, “We knew that these junctions [between skin stem cells] were important in skin stem cells but the cellular components involved in their structure and function were not yet understood.”

For this research, Pérez-Moreno and her team used skin stem cells from laboratory mice. They examined structures called “adherens junctions” between stem cells. Adherens junctions are found at the “apical” (or top) surface of the cells, and they hold cells together. Without adherens junctions, cells would fail to stick together properly.

Adherens junctionCellJunctions

Pérez-Moreno and her team discovered that one of the central structures in skin stem cells that stabilized adherens junctions were microtubules. Microtubules are stiff, tube-like structures that act as rebar-like reinforcement for cells and help cells maintain their shape, form, and structure.

microtubulemicrotubulesfigure2

Marta Shahbazi, a member of Pérez-Moreno’s research group, said,” We have seen for the first time that skin stem cell microtubules connect with cell-cell junctions to form velcro-like structures that hold the cells together.”

The microtubules and the adherens junctions are stuck together by means an interaction between two proteins, the CLASP2 and p120 catenin proteins.

“We found that the absence of CLASP2 or p120 catenin in epidermal stem cells caused a loss of their adhesion , and therefore the structure of these cells,” said Shahbazi.

“Our results will open up new paths for exploring how these proteins regulate skin physiology,” said Perez-Moreno. She also added that such knowledge will be important for the possible development of future regenerative medical treatments or anti-cancer treatments.

The Speed of the Cell Cycle Makes Aging Cells Young Again


When Shinya Yamanaka and his colleagues at the RIKEN Institute discovered a way to reprogram adult cells into embryonic stem cell-like cells, known as induced pluripotent stem cells (iPSCs), they overthrew a core understanding of cell and developmental biology; namely that once cells become committed to a particular cell fate, they irreversibly remain committed to that cell fate.

Most of the work on iPSCs has examined how to increase the efficiency and safety of this reprogramming procedure. The slowness and inefficiency of this process has frustrated stem cell scientists for some time. Even though some progress has been made at increasing the efficiency of the reprogramming process, the “nuts and bolts” of why this procedure is so slow has remained unclear.

However a recent paper from the laboratory of Shangqin Guo at the Yale School of Medicine has revealed a key component of why this procedure is so slow. That component is the speed of the cell cycle or the length of time the cell takes to divide.

Fast-growing cells have lower barriers to keeping the cell committed to a particular cell fate. Thus faster-growing cells are more easily coaxed into being reprogrammed into pluripotency (the ability to differentiate into all adult cell types).

Guo’s research team examined blood cell-forming stem cells in bone marrow. Normally these stem cells are multipotent, which means that they can differentiate into a limited number of adult cell types. The particular type of blood cells that the progeny of these stem cells differentiate into depends on the particular types of growth factors available to the cells.

Guo and others found that these fast growing bone marrow stem cells could be reprogrammed in as little as four cell divisions.  Ultrafast cell cycle is a key feature of these “privileged cells” that can be reprogrammed to efficiently.  Slower-growing stem cells could not be reprogrammed nearly as fast. Thus the length of the cell cycle seemed to be the key to the speed with which cells could be reprogrammed to iPSCs.

This study also has implications for several other applications, besides making individualized iPSCs for patients. Several human diseases are associated with abnormalities in the establishment of proper cell fates and abnormalities in the cell cycle. Therefore, Guo’s paper could provide insights into why certain genetic diseases affect cells the way they do.

Teaching Old Neural Stem Cells New Tricks


In our brains, cells called neurons produce nerve impulses and are responsible for thinking, learning memory, reasoning, and so on. Neurons do not exist in isolation, but in combination with cells called glial cells that support the neurons, nourish them, and protects them from stress damage. Neurons and glial cells are replenished by brain-specific neural stem cell populations in the brain.

Unfortunately, the neural stem cell population in our brains tends to produce far fewer neurons as they age. This deficit of new neurons can play a role in the onset of neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Also, our own “senior moments” when we forget where we placed our iPod or car keys comes from a loss of neurons as we age.

Fortunately, some recent research might change this trend. A team from Japan’s Keio University, and the Riken national research institute, has reported the discovery of a small RNA molecule (micro-RNA) that controls neuron production in young mice. When this micro-RNA was manipulated in older mice, their neural stem cells started to make neurons again. The Japanese team also has reasons to believe that the same mechanism is at work in human brains as well. This research was reported in the journal Proceedings of the National Academies of Science. The mechanism is believed to exist in humans as well.

Senior Author Hideyuki Okano said, “We observed the neurogenic-to-gliogenic switching in developing NSCs.” Translation: Okano and his team examined embryonic mouse brains and their neural stem cell (NSC) populations. They found what many other groups have previously observed: that the developing embryonic brain NSCs create neurons first, then switch over to making glial cells later. Okano’s team also discovered the microRNA-17/106-p38 axis that is responsible for this initial neuron-to-glial cell switch during embryonic development.

When they manipulated this embryonic microRNA-17/106-p38 pathway in older, post-natal NSCs in culture, these older post-natal NSCs switched from making glial cells to producing neurons.

In culture, NSCs are difficult to control, since getting large supplies of neurons from cell cultures that various research groups call NSCs is very difficult.

Nevertheless, “there is general agreement that neurogenesis (make neurons) largely precedes gliogenesis (making glial cells) during CNS development in vertebrates,” Okano explained. And adult NSCs, according to Okano, clearly can produce neurons in the body, “whereas they exhibit strong gliogenic characteristics under culture conditions in vitro (that is, in the laboratory).”

Adult NSCs in two regions of the brain—the subventricular zone and hippocampus—also “make neurons, even though transplant studies have shown us that the adult CNS is a gliogenic environment.”

Subventricular Zone

So it seems clear that old NSCs can make neurons, at least under certain conditions. However, it is very difficult to determine the age at which NSCs begin making substantially more glial cells than neurons. According to Okano, “It is difficult to clearly explain the association between total glial cell number and changes in NSC abilities. Moreover, there is less evidence about gliogenic ability of aged NSCs because most of studies about NSCs have mainly focused on the neurogenic ability. “

Still, Okano says: “There are some reports about decline of neurogenesis ability of NSCs with age. These reports indicate that reduction in paracrine Wnt3 factors, and increase of (chemokine) CCL11 concentration in blood, impaired adult neurogenesis in the hippocampus, for example.”

Could the group’s microRNA approach improve memory in humans? Okano believes so, but says more work needs to be done.

“We observed the neurogenic effect by overexpression of miR-17 in primary cultured neurospheres” – spheres of a variety of cells, including NSCs—“derived from the SVZ at postnatal day 30. Similar phenomenon by overexpression of miR-106b-25 cluster has been reported by another group.”

Okano also warns that his approach has only been attempted in cultured cells. He cautioned, “There is no evidence using knock-out mice. Therefore, the functions of them in adult neurogenesis and learning/memory functions are still unclear.”

Next, Okano’s group will develop “a useful method for precise manipulation of cytogenesis from NSCs. “

However, he says, “we think that further understanding of basic molecular mechanisms underlying the neural development is also an important issue.” He will study the ways in which his microRNA system interacts with other glia-producing genes. He wants to fully understand the mechanisms underlying “the end of neurogenic competence and acquisition of gliogenic competence.”

Finally, the group will “examine the significance of miR-17/p38 pathway in various somatic stem cells other than NSCs,” he says.

When Is the Best Time to Treat Heart Attack Patients With Stem Cells?


Several preclinical trials in laboratory animals and clinical trials have definitively demonstrated the efficacy of stem cell treatments after a heart attack. However, these same studies have left several question largely unresolved. For example, when is the best time to treat acute heart attack patients? What is the appropriate stem cell dose? What is the best way to administer these stem cells? Is it better to use a patient’s own stem cells or stem cells from someone else?

A recent clinical trial from Soochow University in Suzhou, China has addressed the question of when to treat heart attack patients. Published in the Life Sciences section of the journal Science China, Yi Huan Chen and Xiao Mei Teng and their colleagues in the laboratory of Zen Ya Shen administered bone marrow-derived mesenchymal stromal cells at different times after a heart attack. Their study also examined the effects of mesenchymal stem cells transplants at different times after a heart attack in Taihu Meishan pigs. This combination of preclinical and clinical studies makes this paper a very powerful piece of research indeed.

The results of the clinical trial came from 42 heart attack patients who were treated 3 hours after suffering a heart attack, or 1 day, 3 days, 2 weeks or 4 weeks after a heart attack. The patients were evaluated with echocardiogram to ascertain heart function and magnetic resonance imaging of the heart to determine the size of the heart scar, the thickness of the heart wall, and the amount of blood pumped per heart beat (stroke volume).

When the data were complied and analyzed, patients who received their stem cell transplants 2-4 weeks after their heart attacks fared better than the other groups. The heart function improved substantially and the size of the infarct shrank the most. 4 weeks was better than 2 weeks,

The animal studies showed very similar results.

Eight patients were selected to receive additional stem cell transplants. These patients showed even greater improvements in heart function (ejection fraction improved to an average of 51.9% s opposed to 39.3% for the controls).

These results show that 2-4 weeks constitutes the optimal window for stem cell transplantation. If the transplant is given too early, then the environment of he heart is simply too hostile to support the survival of the stem cells. However, if the transplant is performed too late, the heart has already experiences a large amount of cell death, and a stem cell treatment might be superfluous. Instead 2-4 weeks appears to be the “sweet spot” when the heart is hospitable enough to support the survival of the transplanted stem cells and benefit from their healing properties. Also, this paper shows that multiple stem cell transplants a two different times to convey additional benefits, and should be considered under certain conditions.

Cord Blood Stem Cells to Treat Acquired Hearing Loss


The Cord Blood Registry has announced the beginning of an FDA-regulated study at the Florida Hospital for Children in Orlando to investigate the potential of a child’s umbilical cord stem cells to treat acquired sensorineural hearing loss.

In the United States, about 15% of children suffer from low or high frequency hearing loss. Sensorineural hearing loss is the most common type of hearing loss, especially at high frequencies. Acquired sensorineural hearing loss results from damage to hair cells in the inner ear (cochlea) and can be caused by illness, medication, noise exposure, birth injury or head trauma. Because the ability to hear affects language development, hearing impairments can lead to poor academic and social development.

This particular study is a Phase I clinical trial, which will determine the safety and efficacy of using cord blood stem cells in children to improve inner ear function, and speech and language development.

In this study, the research group will follow 10 children who range in age from 6 weeks to 6 years, who have been diagnosed with acquired hearing loss for less than 18 months and who have had their own umbilical cord blood processed and stored.

Unfortunately, children who have a known genetic cause of deafness are ineligible for study participation. Patients will receive one intravenous infusion of their own umbilical cord blood stem cells. All patients will be tested at 1 month after the infusion, 6 months, and 1 year post-treatment.

As usual, this clinical trial is inspired by positive results in preclinical tests in laboratory animals.

Adult Stem Cells Used for Spinal Disc Repair


The Australian regenerative medicine company Mesoblast Limited announced the results of their 12-month clinical trial that examined the use of their “off-the-shelf” product to treat patients with disc-related low back pain.

This phase 2 clinical trial enrolled 100 patients with chronic moderate to severe “discogenic low back pain” and tested the ability of “mesenchymal precursor cells” to shore up degenerating intervertebral discs.

Intervertebral discs

Intervertebral discs sit between each vertebra and act as shock absorbers. Each disc consist of an outer layer called the “annulus fibrosus.” The annulus fibrosus consists of several layers of fibrocartilage. The annulus fibrosus surrounds an inner layer called the nucleus pulposus, which contains loose fibers suspended in a mucoprotein gel with the consistency of jelly. This jelly-like center distributes pressure evenly across the disc. These discs absorb the impact of the body’s daily activities and keep the two vertebrae separated. The development of a prolapsed disc results when the jelly in the nucleus pulposus is forced out of the doughnut/disc, which may put pressure on the nerve located near the disc.

Intervertebral structure

More than six million people in the United States alone deal with chronic back pain that has persisted for at least three months, and 3.5 million people are affected by moderate or severe degenerative intervertebral disc disease.

In this clinical trial, Mesoblast Limited injected their mesenchymal precursor cells (MPCs) into the degenerating intervertebral discs of patients suffering from moderate to severe back pain. When compared with a control group, patients who received the MPC injections used less pain killers, went through fewer surgeries and non-surgical interventions, and had greater disc stability as ascertained by X-rays. MPC injections also were well tolerated and produced few side effects.

This phase 2 clinical trial extends earlier observations by Mesoblast Limited on laboratory animals. In preclinical trials, purified MPCs increased the quality of the jelly content of the nucleus pulposus and improved disc structure in sheep.

This present study enrolled 100 patients at 13 different sites across Australia and the United States with early disc degeneration and randomly assigned the subjects to one of four groups: 1) those who received saline injections; 2) those who received hyaluronic acid injections; 3) those who received low-dose MPCs in hyaluronic acid; and 4) those who received high-dose injections of MPCs in hyaluronic acid.

All patients received their injections in an outpatient procedure, and are being evaluated for safety and efficacy to evaluate long-term treatment effects.

At 12 months, the key findings were improvement in chronic low back pain, function, and disc stability. Also, no safety concerns emerged as a result of the treatment.

As this trial proceeds, more data should be forthcoming.