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.

Synthetic Matrices that Induce Stem Cell-Mediated Bone Formation


Biomimetic matrices resemble living structures even though they are made from synthetic materials. Researchers in the laboratory of Shyni Varghese at the UC San Diego Jacobs School of Engineering have used calcium phosphate to direct mesenchymal stem cells to form bone. In doing so, Varghese and his colleagues have identified a surprising pathway from biomaterials to bone.

Varghese and his colleagues think that their work may point out new targets for treating bone defects, such as major fractures, and bone metabolic disorders such as osteoporosis.

The first goal of this research was to use materials to build something that looked like bone. This way, stem cells harvested from bone marrow (the squishy stuff inside our bones) could sense the presence of bone and differentiate into osteoblasts, the cells in our bodies that build bone.

“We knew for years that calcium phosphate-based materials promote osteogenic differentiation of stem cells, but none of use knew why.” said Varghese. “As engineers, we want to build something that is reproducible and consistent, so we need to know how building factors contribute to this end.”

Varghese and co-workers discovered that phosphate ions dissolved from calcium phosphate-based materials and these stray phosphate ions are taken up by the stem cells and used for the production of adenosine triphosphate or ATP. ATP is the energy currency of the cell, and it is the way cells store energy in a form that is readily usable for powering other reactions.

In stem cells, the generation of ATP eventually increases the intracellular concentration of the ATP breakdown product adenosine, and adenosine signals to stem cells to differentiate into osteoblasts and make bone.

Varghese said that she was surprised that “the biomaterials were connected to metabolic pathways. And we didn’t know how these metabolic pathways could influence stem cells,” and their commitment to bone formation.

These results also explain another clinical observation. Plastic surgeons have been using fat-based stem cells for eyelid lifts, breast augmentation, and other types of reconstructive surgeries. In once case, a plastic surgeon injected a dermal filler that contained calcium hydroxyapatite with the fat-based stem cells into a woman’s eyelid to provide an eye lift. However, the stem cells formed bone, and the poor lady’s lid painfully clicked every time she blinked and she had to have surgery to remove the ectopic bone. These results from Varghese’s laboratory explains why these fat-based stem cells formed bone in this case, and great care should be taken to never use such fillers in fat-based transplantation procedures.

Micro-Grooved Surfaces Influence Stem Cell Differentiation


Martin Knight and his colleagues from the Queen Mary’s School of Engineering and Materials Science and the Institute of Bioengineering in London, UK have shown that growing adult stem cells on micro-grooved surfaces disrupts a particular biochemical pathway that specified the length of a cellular structure called the “primary cilium.” Disruption of the primary cilium ultimately controls the subsequent behavior of these stem cells.

Primary cilia are about one thousand times narrower than a human hair. They are found in most cells and even though they were thought to be irrelevant at one time, this is clearly not the case.

Primary Cilium

The primary cilium acts as a sensory structure that responds to mechanical and chemical stimuli in the environment, and then communicates that external signal to the interior of the cell.  Most of the basic research on this structure was done using a single-celled alga called Chlamydomonas.

Martin Knight and his team, however, are certain that primary cilia in adult stem cells play a definite role in controlling cell differentiation.  Knight said, “Our research shows that they [primary cilia] play a key role in stem cell differentiation.  We found it’s possible to control stem cell specialization by manipulating primary cilia elongation, and that this occurs when stem cells are grown on these special grooved surfaces.”

When mesenchymal stromal cells were grown on grooved surfaces, the tension inside the cells was altered, and this remodeled the cytoskeleton of the cells.  Cytoskeleton refers to a rigid group of protein inside of cells that act as “rebar.” for the cell.  If you have ever worked with concrete, you will know that structural use of concrete requires the use of reinforcing metal bars to prevent the concrete from crumbling under the force of its own weight.  In the same way, cytoskeletal proteins reinforce the cell, give it shape, help it move, and help it resist shear forces.  Remodeling of the cytoskeleton can greatly change the behavior of the cell.

The primary cilium is important for stem cell differentiation.  Growing mesenchymal stromal cells on micro-grooved surfaces disrupts the primary cilium and prevents stem cell differentiation.  This simple culture technique can help maintain stem cells in an undifferentiated state until they have expanded enough for therapeutic purposes.

Once again we that there are ways to milk adult stem cells for all they are worth.  Destroying embryos is simply not necessary to save the lives of patients.

Controlling Transplanted Stem Cells from the Inside Out


Scientists have worked very hard to understand how to control stem cell differentiation.  However, despite how well you direct stem cell behavior in culture, once those stem cells have been transplanted, they will often do as they wish.  Sometimes, transplanted stem cells surprise people.

Several publications describe stem cells that, once transplanted undergo “heterotropic differentiation.” Heterotropic differentiation refers to tissues that form in the wrong place. For example, one lab found that transplantation of mesenchymal stem cells into mouse hearts after a heart attack produced bone (don’t believe me – see Martin Breitbach and others, “Potential risks of bone marrow cell transplantation into infarcted hearts.” Blood 2007 110:1362-1369).  Bone in the heart – that can’t be good. Therefore, new ways to control the differentiation of cells once they have been transplanted are a desirable goal for stem cell research.

From this motivation comes a weird but wonderful paper from Jeffrey Karp and James Ankrum of Brigham and Women’s Hospital and MIT, respectively, that loads stem cells with microparticles that give the transplanted stem cell continuous cues that tell them how to behave over the course of days or weeks as the particles degrade.

“Regardless of where the cell in the body, it’s going to be receiving its cues from the inside,” said Karp. “This is a completely different strategy than the current method of placing cells onto drug-doped microcarriers or scaffolds, which is limiting because the cells need to remain in close proximity to those materials in order to function. Also these types of materials are too large to be infused into the bloodstream.”

Controlling cells in culture is relatively easy. If cells take up the right molecules, they will change their behavior. This level of control, however, is lost after the cell is transplanted. Sometimes implanted cells readily respond to the environment within the body,. but other times, their behavior is erratic and unpredictable. Karp’s strategy, which her called “particle engineering,” corrects this problem by turning cells into pre-programmable units. The internalized particles stably remain inside the transplanted cell and instruct it precisely how to act. It can direct cells to release anti-inflammatory factors, or regenerate lost tissue and heal lesions or wounds.

“Once those particles are internalized into the cells, which can take on the order of 6-24 hours, we can deliver the transplant immediately or even cryopreserve the cells,” said Karp. “When the cells are thawed at the patient’s bedside, they can be administrated and the agents will start to be released inside the cells to control differentiation, immune modulation or matrix production, for example.”

It could take more than a decade for this type of cell therapy to be a common medical practice, but to speed up the pace of this research, Karp published the study to encourage others in the scientific community to apply the technique to their various fields. Karp’s paper also illustrates the range of different cell types that can be controlled by particle engineering, including stem cells, cells of the immune system, and pancreatic cells.

“With this versatile platform, which leveraged Harvard and MIT experts in drug delivery, cell engineering, and biology, we’ve demonstrated the ability to track cells in the body, control stem cell differentiation, and even change the way cells interact with immune cells, said Ankrum, who is a former graduate student in Karp’s laboratory. “We’re excited to see what applications other researchers will imagine using this platform.”

Stem Cell Therapy Following Meniscus Knee Surgery Reduces Pain and Regenerates Meniscus


According to a new study published in the January issue of the Journal of Bone and Joint Surgery (JBJS), a single stem cell injection after meniscus knee surgery can provide pain relief and aid in meniscus regrowth.

In the US alone, over one million knee arthroscopy procedures are performed each year. These surgeries are usually prescribed to treat tears to the wedge-shaped piece of cartilage on either side of the knee called the “meniscus.” The meniscus acts as an important shock absorber between the thighbone (femur) and the shinbone (tibia) at the knee-joint.

Knee-Ligament-Pain-and-Strains-Meniscus-Tear-and-Pain

This novel study, “Adult Human Mesenchymal Stem Cells (MSC) Delivered via Intra-Articular Injection to the Knee, Following Partial Medial Meniscectomy,” examined 55 patients who had undergone a surgical removal or all or part of a torn meniscus (known as a partial medial meniscectomy). Each patient was randomly assigned to one of three treatment groups: Groups A, B and C. The 18 patients in group A received a “low-dose” injection of 50 million stem cells within seven to 10 days after their meniscus surgery. Another 18 patients in group B received a higher dose of 150 million stem cells seven to ten days after their knee surgery. The controls group consisted of 19 patients who received injections of sodium hyaluronate only (no stem cells). All patients were evaluated to determine the safety of the procedure, the degree of meniscus regeneration (i.e. with MRI and X-ray images), the overall condition of the knee-joint, and the clinical outcomes through two years. Most of the patients enrolled in this study had some arthritis, but patients with severe (level three or four) arthritis, were excluded from the study.

Most of the patients who had received stem cell treatments reported a significant reduction in pain. 24 percent of the patients in one MSC group and 6 percent of the other showed at least a 15 percent increase in meniscal volume at one year. Unfortunately, there was no additional increase in meniscal volume at year two.

“The results demonstrated that high doses of mesenchymal stem cells can be safely delivered in a concentrated manner to a knee-joint without abnormal tissue formation,” said lead study author C. Thomas Vangsness, Jr., MD. “No one has ever done that before.” In addition, “the patients with arthritis got strong improvement in pain” and some experienced meniscal regrowth.

The key findings of this study are that there no abnormal (ectopic) tissue formation or “clinically important” safety issues identified. Also, 24 percent of the patients in the low-dose injection group (A) and six percent of the high-dose injection group (B) at one year showed “significantly increased meniscal volume,” as determined by an MRI, and this increase did not continue into the second year, but remained stable (should future studies try a second injection of MSCs?). Third, none of the patients in the control group (non-MSC group) showed significant meniscus regrowth. Finally, patients with osteoarthritis experienced a reduction in pain in the stem cell treatment groups, but there was no reduction in pain in the control (non-MSC group).

“The results of this study suggest that mesenchymal stem cells have the potential to improve the overall condition of the knee joint,” said Dr. Vangsness. “I am very excited and encouraged” by the results. With the success of a single injection, “it begs the question: What if we give a series of injections?”

Transplanted Liver Cells do Better When Co-Cultured with Mesenchymal Stem Cells


Implanting frozen liver cells is a relatively new procedure that has, reportedly, been used to treat very young patients with liver problems. Thawing frozen liver cells, however, tends to cause a fraction of the cells to die off and other damaged cells show poor function.

To ameliorate this problem, researchers at Kings College Hospital, London have used mesenchymal stem cells from fat or umbilical cord to improve the viability and function of frozen liver cells.

Emer Fitzpatrick and her colleagues at Kings College Hospital reasoned that mesenchymal stem cells and the multitudes of healing molecules that these cells secrete should be able to “lend proregenerative characteristics to liver cells.”

Thus by co-culturing thawed liver cells with mesenchymal stem cells from fat or umbilical cord, Fitzpatrick and others demonstrated that the rate of cell survival of the liver cells and their functionality increased in comparison with liver cells grown on their own.

Fitzpatrick hopes that such a co-culture technique might improve the clinical usefulness of frozen liver cells for transplantation.

New Tool for Stem Cell Transplantation into the Heart


Researchers from the famed Mayo Clinic, in collaboration with scientists at a biopharmaceutical biotechnology company in Belgium have invented a specialized catheter for transplanting stem cells into a beating heart.

This new device contains a curved needle with graded openings along the shaft of the needle. The cells are released into the needle and out through the openings in the side of the needle shaft. This results in maximum retention of implanted stem cells to repair the heart.

“Although biotherapies are increasingly more sophisticated, the tools for delivering regenerative therapies demonstrate a limited capacity in achieving high cell retention in the heart,” said Atta Behfar, the lead author of this study and a cardiologist. “Retention of cells is, of course, crucial to an effective, practical therapy.”

Researchers from the Mayo Clinic Center for Regenerative Medicine in Rochester, MN and Cardio3 Biosciences in Mont-Saint-Guibert, Belgium, collaborated to develop the device. Development of this technology began by modeling the dynamic motions of the heart in a computer model. Once the Belgium group had refined this computer model, the model was tested in North America for safety and retention efficiency.

These experiments showed that the new, curved design of the catheter eliminates backflow and minimizes cell loss. The graded holes that go from small to large diameters decrease the pressures in the heart and this helps properly target the cells. This new design works well in healthy and damaged hearts.

Clinical trials are already testing this new catheter. In Europe, the CHART-1 clinical trial is presently underway, and this is the first phase 3 trial to examine the regeneration of heart muscle in heart attack patients.

These particular studies are the culmination of years of basic science research at Mayo Clinic and earlier clinical studies with Cardio3 BioSciences and Cardiovascular Centre in Aalst, Belgium, which were conducted between 2009 and 2010.  This study, the C-CURE or Cardiopoietic stem Cell therapy in heart failURE study examined 47 patients, (15 control and 32 experimental) who received injections of bone marrow-derived mesenchymal stem cells from their own bone marrow into their heart muscle.  Control patients only received standard care.  After six months, those patients who received the stem cell treatment showed an increase in heart function and the distance they could walk in six minutes.   No adverse effects were observed in the stem cell recipients.

This study established the efficacy of mesenchymal stem cell treatments in heart attack patients.  However, other animal and computer studies established the efficacy of this new catheter for injecting heart muscle with stem cells.  Hopefully, the results of the CHART-1 study will be available soon.

Postscript:  The CHART-2 clinical trial is also starting.  See this video about it.

Stem Cells Treat Babies With Brittle Bone Disease While Still in the Womb


A new study published by the journal STEM CELLS Translational Medicine shows that stem cells can be effective in treating brittle bone disease, a debilitating and sometimes lethal genetic disorder.

Also known as osteogenesis imperfecta (OI), this genetic disorder was popularized by actor Samuel T. Jackson in the Bruce Willis movie “Unbreakable.” OI is characterized by fragile bones that cause patients to suffer hundreds of fractures over the course of a lifetime. According to the OI Foundation, other symptoms include muscle weakness, hearing loss, fatigue, joint laxity, curved bones, scoliosis, brittle teeth and short stature. In the more severe cases of OI, restrictive pulmonary disease also occurs. Unfortunately, to date no cure exists for OI.

Physicians use ultrasound to detect OI in babies before they are born. In this study, an international research team treated two patients for the disease with mesenchymal stem cells (MSCs) while the infants were still in the womb. After they were born, the babies were given additional mesenchymal stem cell treatments.

“We had previously reported on the prenatal transplantation for the patient with OI type III, which is the most severe form in children who survive the neonatal period,”said Cecilia Götherström, Ph.D., of the Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden. She and Jerry Chan, M.D., Ph.D., of the Yong Loo Lin School of Medicine and National University of Singapore, and KK Women’s and Children’s Hospital, led the study that also included colleagues from the United States, Canada, Taiwan and Australia.

“The first eight years after the prenatal transplant, our patient did well and grew at an acceptable rate. However, she then began to experience multiple complications, including fractures, scoliosis and reduction in growth, so the decision was made to give her another MSC infusion. In the two years since, she has not suffered any more fractures and improved her growth. She was even able to start dance classes, increase her participation in gymnastics at school and play modified indoor hockey,”Dr. Götherström added.

The second child suffered from a milder form of OI and received a stem cell transfusion 31 weeks into gestation and did not suffer any new fractures for the remainder of the pregnancy or during infancy. She followed her normal growth pattern — just under the third percentile in height, but when she was 13 months old, she stopped growing. Six months later, the doctors gave her another infusion of stem cells and she resumed growing at her previous rate.

“Our findings suggest that prenatal transplantation of autologous stem cells in OI appears safe and is of likely clinical benefit and that re-transplantation with same-donor cells is feasible. However, the limited experience to date means that it is not possible to be conclusive, for which further studies are required,”Dr. Chan said.

“Although the findings are preliminary, this report is encouraging in suggesting that prenatal transplantation may be a safe and effective treatment for this condition,”said Anthony Atala, M.D., editor of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine.

Priming Cocktail for Cardiac Stem Cell Grafts


Approximately 700,000 Americans suffer a heart attack every year and stem cells have the potential to heal the damage wrought by a heart attack. Stem cells therapy has tried to take stem cells cultured in the laboratory and apply them to damaged tissues.

In the case of the heart, transplanted stem cells do not always integrate into the heart tissue. In the words of Jeffrey Spees, Associate Professor of Medicine at the University of Vermont, “many grafts simply didn’t take. The cells would stick or would die.”

To solve this problem, Spees and his colleagues examined ways to increase the efficiency of stem cell engraftment. In his experiments, Spees and others used mesenchymal stem cells from bone marrow. Mesenchymal stem cells are also called stromal cells because they help compose the spider web-like filigree within the bone marrow known as “stroma.” Even though the stroma does not make blood cells, it supports the hematopoietic stem cells that do make all blood cells.  Here is a picture of bone marrow stroma to give you an idea of what it looks like:

Immunohistochemistry-Paraffin: Bone marrow stromal cell antigen 1 Antibody [NBP2-14363] Staining of human smooth muscle shows moderate cytoplasmic positivity in smooth muscle cells.
Immunohistochemistry-Paraffin: Bone marrow stromal cell antigen 1 Antibody [NBP2-14363] Staining of human smooth muscle shows moderate cytoplasmic positivity in smooth muscle cells.
Stromal cells are known to secrete a host of molecules that protect injured tissue, promote tissue repair, and support the growth and proliferation of stem cells.

Spees suspected that some of the molecules made by bone marrow stromal cells could enhance the engraftment of stem cells patches in the heart. To test this idea, Spees and others isolated proteins from the culture medium of bone marrow stem cells grown in the laboratory and tested their ability to improve the survival and tissue integration of stem cell patches in the heart.

Spees tenacity paid off when he and his team discovered that a protein called “Connective tissue growth factor” or CTGF plus the hormone insulin were in the culture medium of these stem cells. Furthermore, when this culture medium was injected into the heart prior to treating them with stem cells, the stem cell patches engrafted at a higher rate.

“We broke the record for engraftment,” said Spees. Spees and his co-workers called their culture medium from the bone marrow stem cells “Cell-Kro.” Cell-Kro significantly increases cell adhesion, proliferation, survival, and migration.

Spees is convinced that the presence of CTGF and insulin in Cell-Kro have something to do with its ability to enhance stem cell engraftment. “Both CTGF and insulin are protective,” said Spees. “Together they have a synergistic effect.”

Spees is continuing to examine Cell-Kro in rats, but he wants to take his work into human trials next. His goal is to use cardiac stem cells (CSCs) from humans, which already have a documented ability to heal the heart after a heart attack. See here, here, and here.

“There are about 650,000 bypass surgeries annually,” said Spees. “These patients could have cells harvested at their first surgery and banked for future application. If they return for another procedure, they could then receive a graft of their own cardiac progenitor cells, primed in Cell-Kro, and potentially re-build part of their injured heart.”

The Therapeutic Potential of Fat-Based Stem Cells Decreases With Age


Fat is a rich source of stem cells for regenerative medicine.  Treating someone with their own stem cells from their own fat certainly sounds like an attractive option.  However, a new study shows that demonstrates that the therapeutic value of fat-based stem cells declines when those cells come from older patients.

“This could restrict the effectiveness of autologous cell therapy using fat, or adipose-derived mesenchymal stromal cells (ADSCs), and require that we test cell material before use and develop ways to pretreat ADSCs from aged patients to enhance their therapeutic potential,” said Anastasia Efimenko, M.D., Ph.D.  Dr Efimenko and Nina Dzhoyashvili, M.D., were first authors of the study, which was led by Yelena Parfyonova, M.D., D.Sc., at Lomonosov Moscow State University, Moscow.

Heart disease remains the most common cause of death in most countries.  Mesenchymal stromal cells (MSCs) collected from either bone marrow or fat are considered one of the most promising therapeutic agents for regenerating damaged tissue because of their ability to proliferate in culture and differentiate into different cell types.  Even more importantly they also have the ability to stimulate the growth of new blood vessels (angiogenesis).

In particular, fat is considered an ideal source for MSCs because it is largely dispensable and the stem cells are easily accessible in large amounts with a minimally invasive procedure.  ADSCs have been used in several clinical trials looking at cell therapy for heart conditions, but most of the studies used stem cells from relatively healthy young donors rather than sick, older ones, which are the typical patients who suffer from heart disease.

“We knew that aging and disease itself may negatively affect MSC activities,” Dr. Dzhoyashvili said. “So the aim of our study was to investigate how patient age affects the properties of ADSCs, with special emphasis on their ability to stimulate angiogenesis.”

The Russian team analyzed age-associated changes in ADSCs collected from patients of different age groups, including some patients who suffered from coronary artery disease and some without.  The results showed that ADSCs from the older patients in both groups showed some of the characteristics of aging, including shorter telomeres (the caps on the ends of chromosomes that protect them from deterioration), which confirms that ADSCs do age.

“We showed that ADSCs from older patients both with and without coronary artery disease produced significantly less amounts of angiogenesis-stimulating factors compared with the younger patients in the study and their angiogenic capabilities lessened,” Dr. Efimenko concluded. “The results provide new insight into molecular mechanisms underlying the age-related decline of stem cells’ therapeutic potential.”

“These findings are significant because the successful development of cell therapies depends on a thorough understanding of how age may affect the regenerative potential of autologous cells,” said Anthony Atala, M.D., director of the Wake Forest Institute for Regenerative Medicine, and editor of STEM CELLS Translational Medicine, where this research was published.

Stem Cell Treatments for Hurler’s Syndrome


Mucopolysaccharidoses are a group of inherited diseases that result from loss-of-function mutations in those genes that encode enzymes that degrade long-chain sugar molecules. One of these mucopolysaccharidoses, Hurler syndrome, is a consequence of the inability to make a functional version of an enzyme called iduronidase. Without functional iduronidase, cells cannot degrade molecules called glycosaminoglycans (formerly called mucopolysaccharides), which are found in mucus and in fluid around the joints. The concentrations of these glycosaminoglycans increase and damage organs, including the heart. Symptoms can range from mild to severe.

From Kowalewski B et al. PNAS 2012;109:10310-10315. Heparan sulfate catabolism involving GlcNS3S structures. The scheme illustrates all nine different enzymatic activities required for the sequential catabolism of a NRE tetrasaccharide containing GlcNS3S. To expose the 3-O-sulfated residue at the terminus, the preceding uronic acid (iduronate 2-O-sulfate in this example) is modified sequentially by iduronate 2-sulfatase and iduronidase. Under normal conditions, the 3-O-sulfate then is removed from GlcNS3S by ARSG, thus generating the substrate for sulfamidase, which removes the N-sulfate group. Subsequently, another six different enzymes (plus again sulfamidase) have to act, which ultimately leads to a complete degradation of the chain. The loss of ARSG activity (MPS IIIE) leads to the accumulation of 3-O-sulfated ARSG substrate that cannot be acted upon by downstream catabolic enzymes. It should be noted that the 2-O-sulfation shown at the glucuronic acid (third residue) is relatively rare, which agrees with the finding that no pentasulfated trisaccharides were found as NRE structures (Fig. 3A). Scheme modified from Neufeld and Muenzer (6) according to findings from this work and from Lawrence et al.
From Kowalewski B et al. PNAS 2012;109:10310-10315.
Heparan sulfate catabolism involving GlcNS3S structures. The scheme illustrates all nine different enzymatic activities required for the sequential catabolism of a NRE tetrasaccharide containing GlcNS3S. To expose the 3-O-sulfated residue at the terminus, the preceding uronic acid (iduronate 2-O-sulfate in this example) is modified sequentially by iduronate 2-sulfatase and iduronidase. Under normal conditions, the 3-O-sulfate then is removed from GlcNS3S by ARSG, thus generating the substrate for sulfamidase, which removes the N-sulfate group. Subsequently, another six different enzymes (plus again sulfamidase) have to act, which ultimately leads to a complete degradation of the chain. The loss of ARSG activity (MPS IIIE) leads to the accumulation of 3-O-sulfated ARSG substrate that cannot be acted upon by downstream catabolic enzymes. It should be noted that the 2-O-sulfation shown at the glucuronic acid (third residue) is relatively rare, which agrees with the finding that no pentasulfated trisaccharides were found as NRE structures (Fig. 3A). Scheme modified from Neufeld and Muenzer according to findings from this work and from Lawrence et al.

Hurler syndrome is inherited, and both parents must pass the faulty gene to inherit Hurler syndrome.

The symptoms of Hurler syndrome usually appear between ages 3 and 8. Infants with severe Hurler syndrome appear normal at birth. Facial symptoms may become more noticeable during the first 2 years of life. The most common symptoms include abnormal bones in the spine, claw hand, cloudy corneas, deafness, halted growth, heart valve problems, joint disease (including stiffness),
Intellectual disability that gets worse over time, and thick, coarse facial features with a low nasal bridge.

Hurler’s syndrome appears in about 1 in 100,000 live births, and those afflicted with it normally die in their teens.

Treatments for Hurler Syndrome include “enzyme replacement,” which is very expensive. Enzyme replacement therapy utilizes genetic engineering to make large quantities of iduronidase, which is then administered to Hurler Syndrome patients. A second treatment is bone marrow transplantation, but this requires finding a good tissue match.

Sharon Byers from the University of Adelaide, Australia and her colleagues are genetically modifying adult stem cells (mesenchymal stem cells, specifically) to make large quantities of iduronidase. These modified stem cells are then infused into Hurler Syndrome patients. To date, these experimental treatments seem to be providing Hurler Syndrome patients some relief, but it is still early in the trial.

Matilda Jackson, a PhD candidate in Byers lab, described their trial in this manner: “We have turned adult stem cells into little ‘enzyme factories” by coupling them with a virus that makes them pump out high levels of the enzyme.” Matilda Jackson is a member of the School of Molecular and Biochemical Sciences and Adelaide University.

Dr. Jackson continued, “Those stem cells can then be injected into the blood where they move around the body and become liver or bone or brain or other cells and start producing the missing enzyme. They automatically migrate to areas of damage in the affected individual. So far in our laboratory studies we’ve measured improvements in brain function but we’ve yet to complete the analysis to determine if there are improvements in other organs.”

Sharon Byers, an affiliate senior lecturer in the School of Molecular and Biomedical Sciences, explained, “There are two current treatments for Hurler’s Syndrome: costly enzyme replacement therapy or bone marrow transplants which require a perfectly matched donor. And while they bring some improvements,, neither of these treatments prevents damage to the brain and bones because not enough enzyme reaches either of these tissues.”

Dr. Byers continued: “These stem cells, modified so that produce large quantities of the enzyme that people with Hurler’s Syndrome lack, offer great hope for a potential new therapy. If we can help reverse the disease symptoms, we could see these children able to perform normal tasks, giving them a better quality of life and increasing their life span.”

Stem Cells Decrease Brain Inflammation and Increase Cognitive Ability After Traumatic Brain Injury


A study at the Texas Health Science Center has shown that stem cell treatments that quash inflammation soon after traumatic brain injury (TBI) might also offer lasting cognitive gains.

TBI sometimes causes severe brain damage, and it can also lead to recurrent inflammation of the brain.  This ongoing inflammation can extend the damage to the brain.  Only a few drugs help (anti-inflammatory drugs for example).  Up to half of patients with serious TBI need surgery, but some stem cells like a sub group of mesenchymal stem cells called multipotent adult progenitor cells (MAPCs) can reduce short-term inflammation, and induce functional improvement in mice with TBI.  Unfortunately, few groups have gauged the long-term effects of MAPCs on TBI.

Differentiation of MultiStem® cells into alkaline-phosphatase-positive osteoblasts (blue) and lipid-accumulating adipocytes (red).
Differentiation of MultiStem® cells into alkaline-phosphatase-positive osteoblasts (blue) and lipid-accumulating adipocytes (red).

In an article that appeared in the journal Stem Cells Translational Medicine, a research team led by the Director of the Children’s Program in Regenerative Medicine, Charles Cox, reported the use of human MAPCs in mice that had suffered TBI.

Charles Cox, Jr., MD
Charles Cox, Jr., MD

In this study, Cox and his colleagues infused MAPCs into the bloodstream of two groups of mice 2, and 24 hours after suffering a TBI.  The first group of mice received two million cells per kilogram, and mice in the other group received an MAPC dose five times stronger.

Four months after MAPC administration, those mice that had received the stronger dose continued to experience less brain inflammation and better cognition.  Spatial learning was increased and motor deficits had decreased.

According to Cox, the intravenously administered MAPCs did not cross the blood/brain barrier.  Since immune cells can cross the blood/brain barrier for a short period of time after a TBI and cause autoimmunity, this result shows that the MAPCs are quelling inflammation through “paracrine” mechanisms (paracrine means that molecules are secreted by the cells and these secreted molecules elicit various responses from nearby cells). Cox made this clear: “We spent 18 months looking for them in the brain. There was little to no engraftment there.”

Rather than entering the brain, the MAPCs “set up shop in the spleen, a giant reservoir of T and B cells. The MAPCs change the spleen’s output to anti-inflammatory cells and cytokines, which communicate with immune cells in the brain—microglia—and change their response to injury from hyper-to-anti- inflammatory. The cells alter the innate immune response to injury. We have shown this in a sequence of papers.”

Microglia
Microglia

University of Cambridge neurologist, Stefano Pluchino, has worked with immune regulatory stem cells.  Pluchino said that Cox’s study shows a “good dose response” on disability and behavior “after hyperacute, or acute, intravenous injection of MAPCs.”  However, Pluchino noted that the description of the effects of MAPCs on microglia (white blood cells in the brain that gobble up foreign matter and cell debris) is “speculative.”  Pluchino continued: “It is not clear whether these counts have been done on the injured brain hemisphere, and whether MAPC effects were observable on the unaffected hemisphere.  The distribution and half-life of these MAPCs is not clear” and has never been demonstrated convincingly in Athersys papers (side note: Athersys is the company that isolates and grows the human MAPCs). “It is also not clear if effects in the Cox study were a ‘false positive,’ secondary to a paradoxical immune suppression the xenograft modulates.” That is, a false positive could occur because human cells in animal bodies rouse immune reactions. “It is not clear where in the body these MAPCs would work, either out or into the injured brain.” Additionally the mechanism by which these cells act does not seem to be clear, according to Pluchino.

But, Pluchino added: “Athersys is already in clinic with MAPCs in graft vs. host disease, myocardial infarction, stroke, progressing towards a phase I/II clinical trial in multiple sclerosis, and completing the pre-clinical work in traumatic brain and spinal cord injuries. Everything looks great. The company is solid. The data is convincing in terms of behavioral and pathological analyses. But the points I have raised are far from clarified.”

Cox admitted that Pluchino’s points are valid.  He pointed out that human cells were used in rodents, since the FDA wants pre-clinical studies in laboratory animals in order to first evaluate the safety and efficacy of the exact cells to be used in a proposed therapy before they head to the clinic. “As we are not seeking engraftment of these cells, and would not plan to immunosuppress a trauma patient, we have not pursued animal models that use immunosuppression. Our study was designed with translationally relevant end-points, recognizing the limitations of not having a final mechanism of action determined. The growing consensus is there are many mechanism(s) of action in cell therapies.”

Cox also agreed that the suggested effects of MAPCs on microglia, “is not truly a proof of mechanism.”  However, Cox and his co-workers have developed a protocol that can potentially more accurately quantify microglia in mice. “We ultimately plan more mechanistic studies to define endogenous microglia versus infiltrating microglia and the effects of various cell therapies. “

Additionally, Cox also said that: “We have published work showing the majority of acutely infused MSCs and MAPCs are lodged in the lung after intravenous delivery. This was an acute study in non-injured animals, but others have shown similar data.” In another study, Cox’s research group showed that the cells cluster in the spleen, which corroborates work by other research groups that have used umbilical cord cells to treat stroke.

Finally, Cox disagrees that the suppression of immune cell function in animals by human cells is appropriately characterized as “a false positive.”  Cox explained that the infused cells induce a “modulation of the innate immune response, and typically, the immune rejection of a transplant is associated with immune activation, not suppression. So it well may be a ‘true positive.’”

In order for MAPCs to make to the clinical trial stage, Cox will need to investigate the mechanisms by which MAPCs suppress inflammation and if their purported effects on microglia in the central nervous system are real.  He will also need to show that these cells work in other types of laboratory animals beside mice.  Rats will probably be next, and after that, my guess is that the FDA would allow Athersys to apply for a New Drug Application.

Stem Cell Treatments to Improve Blood Flow in Angina Patients


Angina pectoris is defined as chest pain or discomfort that results from poor blood flow through the blood vessels in the heart and is usually activated by activity or stress.

In Los Angeles, California, physicians have initiated a double-blind, multicenter Phase III clinical trial that uses a patient’s own blood-derived stem cells to restore circulation to the heart of angina patients.

This procedure utilizes state-of-the-art imaging technology to map the heart and generate a three-dimensional image of the heart. These sophisticated images will guide the physicians as they inject stem cells into targeted sites in the heart.

This is a double-blinded study, which means that neither the patients nor the researcher will know who is receiving stem-cell injections and who is receiving the placebo.

The institution at which this study is being conducted, University of Los Angeles (UCLA), is attempting to establish evidence for a stem cell treatment that might be approved by the US Food and Drug Administration for patients with refractory angina. The subjects in this study had received the standard types of care but did not receive relief. Therefore by enrolling in this trial, these patients had nothing to lose.

Dr. Ali Nasir, assistant professor of cardiology at the David Geffen School of Medicine and co-principal investigator of this study, said: “We’re hoping to offer patients who have no other options a treatment that will alleviate their severe chest pain and improve their quality of life.”

Before injecting the stem cells or the placebo, the team examined the three-dimensional image of the heart and ascertained the health of the heart muscle and voltage it generated. Damaged areas of the heart fail to produce adequate quantities of voltage and show low levels of energy.

Jonathan Tobis, clinical professor of cardiology and director of interventional cardiology research at Geffen School of Medicine, said: “We are able to tell by the voltage levels and motion which area of the [heart] muscle is scarred or abnormal and not getting enough blood and oxygen. We then targeted the injections to the areas just adjacent to the scarred and abnormal heart muscle to try to restore some of the blood flow.”

What did they inject? The UCLA team extracted bone marrow from the pelvic bones and isolated CD34+ cells. CD34 refers to a cell surface protein that is found on bone marrow stem cells and mediates the adhesion of bone marrow stem cells to the bone marrow matrix. It is found on the surfaces of hematopoietic stem cells, placental cells, a subset of mesenchymal stem cells, endothelial progenitor cells, and endothelial cells of blood vessels. These are not the only cells that express this cell surface protein, but it does list the important cells for our purposes. Once the CD34+ cells were isolated, the were injected into the heart through a catheter that was inserted into a vein in the groin.

CD34

The team hopes that these cells (a mixture of mesenchymal stem cells, hematopoietic stem cells, and endothelial progenitor cells) will stimulate the growth of new blood vessels (angiogenesis) in the heart, and improve blood flow and oxygen delivery to the heart muscle.

“We will be tracking patients to see how they’re doing,” said William Suh MD, assistant clinical professor of medicine in the division of cardiology at Geffen School of Medicine.

The goal of this study is to enroll 444 patients nation-wide, of which 222 will receive the stem cell treatment, 111 will receive the placebo, and 111 who will be given standard heart care.

Stem Cell Therapy for Patients with Ischemic Cardiomyopathy


A medical research group from Miami Miller School of Medicine has examined the safety of transendocardial stem cell injections with a patient’s own bone marrow stem cells in patients with ischemic cardiomyopathy.

Ischemic cardiomyopathy is the most common type of “dilated cardiomyopathy,” which is a fancy way of saying that the heart enlarges in its failing struggle to supply the body with blood. The enlarged heart has more heart muscle to feed with oxygen, but because the heart enlarges faster than the blood vessels remodel, large portions of the enlarged heart are left without adequate blood supply, and the result is and oxygen deficit, also known as “ischemia.” In patients with ischemic cardiomyopathy, the heart’s ability to pump blood is decreased because the heart’s main pumping chamber, the left ventricle, is enlarged, dilated and weak. Usually, heart ischemia also results from coronary artery disease and heart attacks.

The symptoms of ischemic CM include shortness of breath, swelling of the legs and feet (edema), Fatigue (feeling overly tired), inability to exercise, or carry out activities as usual, angina (chest pain or pressure that occurs with exercise or physical activity and can also occur with rest or after meals), weight gain, cough and congestion related to fluid retention, palpitations or fluttering in the chest due to abnormal heart rhythms (arrhythmia), dizziness or light-headedness, and fainting (caused by irregular heart rhythms, abnormal responses of the blood vessels during exercise, without apparent cause).

Clearly an effective regenerative treatment of ischemic cardiomyopathy (ICM) would address of the needs of some of these patients. Bone marrow transplants into the heart have been tested as treatments and the stem cells were directly injected into the heart muscle (see Williams AR, et al., Circ Res. 2011;108(7):792-796; and Losordo DW, et al., Circ Res. 2011;109(4):428-436). Both of these studies, however used mononuclear cells from bone marrow. Mononuclear cells refer to white blood cells from bone marrow and it includes a wide variety of stem cells, progenitor cells, and other mature white blood cells, but excludes red blood cells or platelets, which have no nuclei.

In order to determine if mesenchymal stem cells were also safe for this type of treatment, Alan W. Haldman and his colleagues from the laboratory of Joshua M. Hare tested 65 patients who suffered from ICM and compared injection of mesenchymal stem cells (n = 19) with placebo (n = 11) and bone marrow mononuclear cells (n = 19). Patients were followed up to one year after their procedures.

To measure serious adverse effects of the procedure, all patients were evaluated at 30 days post-procedure. Severe adverse effects includes death, heart attack, stroke, hospitalization for worsening heart failure, perforation of rupture of the heart, tamponade (compression of the heart due to a collection of fluid around it), or sustained ventricular arrhythmias.

None of the patients in this study showed any severe adverse events up to day 30, and up to 1 year after the procedure, 31.6% of the bone marrow mononuclear and mesenchymal stem cell groups had some sort of serious adverse event, and 38.1% of the placebo group had serious adverse events.

Over one year, the Minnesota Living with Heart Failure score, which is a measure of the quality of life of a heart patient, improved with the mesenchymal stem cell and bone marrow cells but not with the placebo. Also, the 6-minute walk distance increased in the mesenchymal stem cell group, but none of the other groups when the baseline time was compared with the six-month and 12-month trials.

Patients in the mesenchymal stem cell group exhibited a significant increase in 6-minute walk distance when 6-month and 12-month time points were compared to baseline in a repeated measures model (P = .03). No significant difference was observed for patients in the bone marrow cell group (P = .73) or in the placebo group (P = .25). Data markers represent means; error bars, 95% CIs. Analysis of variance (ANOVA) was conducted with repeated measures.aWithin group, P<.05.bWithin group, P<.01.
Patients in the mesenchymal stem cell group exhibited a significant increase in 6-minute walk distance when 6-month and 12-month time points were compared to baseline in a repeated measures model (P = .03). No significant difference was observed for patients in the bone marrow cell group (P = .73) or in the placebo group (P = .25). Data markers represent means; error bars, 95% CIs. Analysis of variance (ANOVA) was conducted with repeated measures.aWithin group, P

Also, the size of the heart scar showed greater shrinkage in the mesenchymal stem cell group than in the other groups.

Significant reduction in scar size as the percentage of left ventricular mass for patients treated with mesenchymal stem cells (MSCs) and those in the placebo group who underwent serial magnetic resonance imaging. Repeated measures of analysis of variance model P values: treatment group, P=.99; time, P=.007; treatment group × time, P=.22. Data markers represent means; error bars, 95% CIs. Analysis of variance (ANOVA) was conducted with repeated measures.aWithin group, P<.05 vs baseline.bWithin group, P<.01 vs baseline.
Significant reduction in scar size as the percentage of left ventricular mass for patients treated with mesenchymal stem cells (MSCs) and those in the placebo group who underwent serial magnetic resonance imaging. Repeated measures of analysis of variance model P values: treatment group, P=.99; time, P=.007; treatment group × time, P=.22. Data markers represent means; error bars, 95% CIs. Analysis of variance (ANOVA) was conducted with repeated measures.aWithin group, P

And if a more visual way to view this would help, here is the heart of one particular patient.  Notice the shrinkage in the red area, which represents the scarred area, after one year.

A, Short-axis views of the basal area of a patient’s heart, with delayed tissue enhancement delineated at the septal wall. Delayed tissue enhancement corresponds to scarred tissue and is depicted brighter than the nonscarred tissue (automatically detected and delineated with red using the full width at half maximum technique). The red, green, and white lines demarcating the endocardial, epicardial contours, and borders of the segments, respectively, were drawn manually. Twelve months after injection of mesenchymal stem cells, scar mass was reduced from 30.85 g at baseline to 21.17 g at 12 months. B, Long-axis 2-chamber views of the same heart with delayed tissue enhancement delineated at the anterior and inferior wall, as well as the entire apex. At baseline and at 12 months after injection of mesenchymal stem cells, the delayed tissue enhancement receded in the midinferior and basal anterior walls (see Interactive of representative cardiac MRI cine sequences).
A, Short-axis views of the basal area of a patient’s heart, with delayed tissue enhancement delineated at the septal wall. Delayed tissue enhancement corresponds to scarred tissue and is depicted brighter than the nonscarred tissue (automatically detected and delineated with red using the full width at half maximum technique). The red, green, and white lines demarcating the endocardial, epicardial contours, and borders of the segments, respectively, were drawn manually. Twelve months after injection of mesenchymal stem cells, scar mass was reduced from 30.85 g at baseline to 21.17 g at 12 months. B, Long-axis 2-chamber views of the same heart with delayed tissue enhancement delineated at the anterior and inferior wall, as well as the entire apex. At baseline and at 12 months after injection of mesenchymal stem cells, the delayed tissue enhancement receded in the midinferior and basal anterior walls (see Interactive of representative cardiac MRI cine sequences).

The authors concluded from this study that these “results provide the basis for larger studies to provide definitive assessment of safety and to assess efficacy of this new therapeutic approach.”  Mesenchymal stem cells might certainly provide a way to treat ICM patients.  Also, if the patient’s bone marrow is of poor quality as a result of their poor health, then mesenchymal stem cells from a donor might provide healing for these patients.  For now, I say, “bring on the larger trials!!”

Human Fat Contains Multilineage Differentiating Stress Enduring Cells With Great Potential for Regenerative Medicine


A collaboration between American and Japanese scientists has discovered and characterized a new stem cell population from human fat that do not cause tumors and can differentiate into derivatives from ectoderm, mesoderm, and endoderm.

Multilineage Differentiating Stress-Enduring or Muse cells are found in bone marrow and the lower layers of the skin (dermis). Muse cells are a subpopulation of mesenchymal stem cells, and even express a few mesenchymal stem cell-specific genes (e.g., CD105, a cell-surface protein specific to mesenchymal stem cells). However, Muse cells also express cell surface proteins normally found in embryonic stem cells (e.g., stage-specific embryonic antigen-3, SSEA-3). Additionally, Muse cells have the ability to self-renew, and differentiate into cell types from all three embryonic germ layers, ectoderm (which forms skin and brain), mesoderm, (which forms muscle, bone, kidneys, gonads, heart, blood vessels, adrenal glands, and connective tissue), and endoderm (which forms the gastrointestinal tract and its associated tissues). Finally, Muse cells can home to damaged sites and spontaneously differentiate into tissue-specific cells as dictated by the microenvironment in which the cells find themselves.

A new publication by Fumitaka Ogura and others from Tohoku University Graduate School of Medicine in Sendai, Japan and Saleh Heneidi from the Medical College of Georgia (Augusta, Georgia), and Gregorio Chazenbalk from the David Geffen School of Medicine at UCLA has shown that Muse cells also exist in human fat.

The source of cells came from two places: commercially available fat tissue and freshly collected fat from human subjects, collected by means of liposuction. After growing these cells in culture, the mesenchymal stem cells and Muse cells grew steadily over the 3 weeks. Then the Dezawa research group used fluorescence-activated cell sorting (FACS) to isolate from all these cells those cells that express SSEA-3 on their cell surfaces.

FACS uses antibodies conjugated to dyes that can bind to specific cell proteins. Once the antibodies bind to cells, the cells are sluiced through a small orifice while they are illuminated by the laser. The laser activates the dyes if the cell fluoresces, one door opens and the other closes. The cell goes to one test tube. If the cell does not fluoresce, then the door stay shut and another door opens and the cell goes into a different test tube.  In this way, cells with a particular cell-surface protein are isolated from other cells that do not have that cell-surface protein.

Fluorescent-Activated Cell Sorting
Fluorescent-Activated Cell Sorting

In addition to expression SSEA-3, the fat-based Muse cells expressed other mesenchymal stem cell-specific cell-surface proteins (CD29, CD90), but they did not express proteins usually thought to be diagnostic for fat-based mesenchymal stem cells (MSCs) such as CD34 and CD146.  Muse cells also expressed pluripotency genes (Nanog, Oct3/4, PAR4, Sox2, and Tra-1-81).  The Muse cells grew in small clusters and some cell expressed ectodermal-specific genes (neurofilament, MAP2), others expressed mesodermal-specific genes (smooth muscle actin, NKX2) and endodermal-specific genes (alpha-fetoprotein, GATA6).  These data suggested that the cultured Muse cells were poised to form either ectoderm, mesodermal, or endodermal derivatives.

When transplanted into mice with non-functional immune systems, the Muse cells never formed any tumors or disrupted the normal structure of the nearly tissues.  When placed in differentiating media, fat-derived Muse cells differentiated into cells with neuron-like morphology that expressed neuron-specific genes (Tuj-1), liver cells, and fat.  When compared with Muse cells from bone marrow or skin, the fat-derived Muse cells were better at making bone, fat, and muscle, but not as good as bone marrow Muse cells at making neuronal cell types, but not as good at making glial cells.  Many of these assays were based on gene expression experiments and not more rigorous tests.  Therefore, the results of these experiments might be doubtful until they are corroborated by more rigorous experiments.

These cells are expandable and apparently rather safe to use.  More work needs to be done in order to fully understand the full regenerative capacity of these cells and protocols for handling them must also be developed.  However, hopefully pre-clinical experiments in rodents will give way to larger animal experiments.  If these are successful, then maybe human trials come next.  Here’s to hoping.

Adult Stem Cells Help Build Human Blood Vessels in Engineered Tissues


University of Illinois researchers have identified a protein expressed by human bone marrow stem cells that guides and stimulates the construction of blood vessels.

Jalees Rehman, associate professor of cardiology and pharmacology at the University of Illinois at Chicago College of Medicine and lead author of this paper, said: “Some stem cells actually have multiple jobs.”

As an example, stem cells from bone marrow known as mesenchymal stem cells can form bone, cartilage, or fat, but they also have a secondary role in that they support other cells in bone marrow.

Rehman and others have worked on developing engineered tissues for use in cardiac patients, and they noticed that mesenchymal stem cells were crucial for organizing other cells into functional stem cells.

Workers from Rehman’s laboratory mixed mesenchymal stem cells from human bone marrow with endothelial cells that line the inside of blood vessels. The mesenchymal stem cells elongated and formed a kind of scaffold upon which the endothelial cells adhered and organized to form tubes.

“But without the stem cells, the endothelial cells just sat there,” said Rehman.

When the cell mixtures were implanted into mice, blood vessels formed that were able to support the flow of blood. Then Rehman and his colleagues examined the genes expressed when their stem cells and endothelial cells were combined. They were aided in this venture by two different bone marrow stem cell lines, one of which supported the formation of blood vessels, and the other of which did.

Their microarray experiments showed that the vessel-supporting mesenchymal stem cells expressed high levels of the SLIT3 protein. SLIT3 is a blood vessel-guidance protein that directs blood vessel-making cells to particular places and induces them to make blood vessels. The cell line that do not stimulate blood vessel production made little to no SLIT3.

Rehman commented, “This means that not all stem cells are created alike in terms of their SLIT3 production and their ability to encourage blood vessel formation.”

Rehman continued: “While using a person’s own stem cells for making blood vessels is ideal because it eliminates the problem of immune rejection, it might be a good idea to test a patient’s stem cells to make sure they are good producers of SLIT3. If they aren’t, the engineered vessels may not thrive or even fail to grow.

Mesenchymal stem cells injections are being evaluated in clinical trials to see if their can help grow blood vessels and improve heart function in patients who have suffered heart attacks.

So far, the benefits of stem cell injection have been modest, according to Rehman. Evaluating the gene and protein signatures of stem cells from each patient may allow for a more individualized approach so that every patient receives mesenchymal stem cells that are most likely to promote blood vessel growth and cardiac repair. Such pre-testing might substantially improve the efficacy of stem cell treatments for heart patients.

The Benefits of Repeated Mesenchymal Stem Cell Treatments to the Heart


Mesenchymal stem cells have the ability to improve the heart after a heart attack. However can repeated administrations of mesenchymal stem cells cause an increased benefit to the heart after a heart attack?

A collaborative research project between the Royal Adelaide Hospital, the University of Adelaide in South Australia, and the Mayo Clinic in Rochester, Minnesota has administered mesenchymal stem cells multiple times to rodents after a heart attack to determine if administering these stem cells multiple times after a heart attack increases the performance of the heart.

The experimental procedure was relatively straight-forward. Three groups of mice were evaluated by means of cardiac magnetic resonance imaging (MRI). Then all three were given heart attacks by tying off the left anterior descending artery. Immediately after the heart attack, two groups were injected with one million mesenchymal stem cells into the heart. The third group was injected with ProFreeze (a cryopreservation solution). One week later, a second set of heart MRIs were taken, and the first and third group of mice received injections of ProFreeze and the third group received another one million mesenchymal stem cells. All animals were given two more heart MRIs one week later and two weeks after that. One month after the initial heart attacks, the mice were euthanized and their hearts were sectioned and examined.

Those mice that did not receive injections of mesenchymal stem cells showed a precipitous drop in their heart performance. The ejection fraction (average percent of blood pumped from the heart) dropped from around 60% to about 20% and then stayed there. Those mice treated with one round of mesenchymal stem cells (MSCs) after their ejection fractions drop from 60% to about 35% after one week, and then stayed there. Those animals that received two shots of MSCs have their ejection fractions drop from around 60% to about 41%. Thus the administration of a second round of MSCs did significantly increase the performance of the heart.

The heart also shows tremendous structural improvements as a result of MSC transplantation. These improvements are even more dramatic in those mice that received two doses of MSCs. The mass of the heart and the thickness of the walls of the heart are greater in those animals that received two MSC doses, than those that received only one dose. Secondly, the size of the heart scar is smallest in those animals that received two doses of MSCs. Third, the density of blood vessels was MUCH higher in the animals that received two MSC doses. Also, the tissue far from the infarction in those animals that had received two doses of MSCs showed twice the density of blood vessels per cubic millimeter of heart tissue than those animals that had only received one injection of MSCs. Therefore, additional transplantations of MSCs increase blood vessel density, decrease the size of the heart scar and increase the thickness of the walls of the heart.

MSCs have the capacity to heal the heart after a heart attack. The degree to which they heal the heart differs from patient to patient, but additional treatments have the capacity to augment the healing capacities of these cells.  Also, in this experiment, the mice received someone else’s MSCs.  This is known as “allogeneic” transplantation, and it is an important concept, since older patients, diabetic patients, or those who have had a heart attack typically have MSCs that do not perform well.  Therefore to receive MSCs from a donor is a way around this problem.

The problem with this experiment is that it was done in mice, and they were injected directly into the heart tissue. Such a procedure is almost certainly impractical for human patients. Instead, intracoronary delivery is probably more practical, but here again, repeated releasing cells into the coronary arteries increases the risk of clogging them. Therefore, it is probably necessary to administer the second dose of MSCs some time after the first dose. To calibrate when to administer the second dose, large animal experiments will be required.

Thus, while this experiment looks interesting and hopeful, more work is required to make this usable in humans.  It does, however, establish the efficacy of repeated allogeneic MSC transplantations, which is an important feature of these experiments.

Stem Cells Build “Biobridges” to Aid Brain Repair


University of South Florida (USF) scientists have suggested a new strategy for stem cell-mediated brain repair following trauma.

In several preclinical experiments, the USF group found that transplanted stem cells build a “biobridge” that links an injured site in the brain to a site where neural stem cells form.

Principal investigator, Cesar Borlongan, professor and director of the USF Center for Aging and Brain Repair, said: “The transplanted stem cells serve as migratory cues for the brain’s own neurogenic cells, guiding the exodus of these formed host cells from their neurogenic niche towards the injured brain.”

Cesar Borlongan
Cesar Borlongan

On the strength of these preclinial studies in laboratory animals, the US Food and Drug Administration recently approved a limited clinical trial to transplant SanBio Inc.’s SB632 cells into patients with traumatic brain injuries. SB632 cells are a proprietary product of SanBio, Inc., and SB632 cells are derived from mesenchymal stem cells but they have been genetically engineered to express the intracellular domain of the Notch protein (NICD; see C. Tate, et al., Cell Transplantation, Vol. 19, pp. 973–984, 2010). If the Notch protein, which functions as a signaling protein and normally sits in the cell membrane, has its outer piece removed, the protein is constitutively activated. This full-time activation of the Notch protein and its downstream targets drive SB632 cells to form neural cells; something that mesenchymal stem cells typically do not readily make.

The Notch pathway. Notch is synthesised as a precursor protein that is processed by a furin-like convertase (S1 cleavage) in the Golgi before being transported to the cell surface, where it resides as a heterodimer. Interaction of Notch receptors with Notch ligands, such as Delta-like or Jagged, between two bordering cells leads to a cascade of proteolytic cleavages. The first cleavage (S2 cleavage) is mediated by ADAM-family metalloproteases such as ADAM10 or TNF-alpha-converting enzyme (TACE, also known as ADAM17), generating a substrate for S3 cleavage by the gamma-secretase complex. This cleavage releases the Notch intracellular domain (NICD) from the cell membrane. NICD then translocates to the nucleus, where it interacts with the DNA-binding protein RBP-Jkappa (also known as CBF1) and cooperates with Mastermind to displace corepressor proteins, thus activating the transcription of Notch target genes. The basic helix-loop-helix proteins hairy/enhancer of split (such as Hes1, 5 and 7) and Hes-related proteins (Hey1, 2 and L) and EphrinB2 are the best characterised downstream targets. Blockade of Notch signalling has been achieved by using different strategies, including (A) anti-DLL4 monoclonal antibodies, (B) gamma-secretase inhibitors such as DBZ and DAPT, (C) soluble DLL4-Fc, (D) anti-Notch1 neutralising antibodies, and (E) Notch1-trap.
The Notch pathway. Notch is synthesised as a precursor protein that is processed by a furin-like convertase (S1 cleavage) in the Golgi before being transported to the cell surface, where it resides as a heterodimer. Interaction of Notch receptors with Notch ligands, such as Delta-like or Jagged, between two bordering cells leads to a cascade of proteolytic cleavages. The first cleavage (S2 cleavage) is mediated by ADAM-family metalloproteases such as ADAM10 or TNF-alpha-converting enzyme (TACE, also known as ADAM17), generating a substrate for S3 cleavage by the gamma-secretase complex. This cleavage releases the Notch intracellular domain (NICD) from the cell membrane. NICD then translocates to the nucleus, where it interacts with the DNA-binding protein RBP-Jkappa (also known as CBF1) and cooperates with Mastermind to displace corepressor proteins, thus activating the transcription of Notch target genes. The basic helix-loop-helix proteins hairy/enhancer of split (such as Hes1, 5 and 7) and Hes-related proteins (Hey1, 2 and L) and EphrinB2 are the best characterised downstream targets. Blockade of Notch signalling has been achieved by using different strategies, including (A) anti-DLL4 monoclonal antibodies, (B) gamma-secretase inhibitors such as DBZ and DAPT, (C) soluble DLL4-Fc, (D) anti-Notch1 neutralising antibodies, and (E) Notch1-trap.

While this over-simplifies the field to some extent, there are two views on how stem cells heal brain damage caused by injury or neurodegenerative disorders. One view postulates that stem cells implanted into the brain directly replace dead or dying cells by differentiating into neurons and glial cells. The other view is that transplanted stem cells secrete growth factors that indirectly rescue the injured tissue. This present USF study argues for a third view, namely that implanted stem cells for a causeway in the brain between damaged areas and those anatomical structures that give birth to neural stem cells.

In this USF study, Borlongan and his group randomly assigned rats with traumatic brain injury and confirmed neurological impairment to one of two groups. The first group received transplants of SB632 cells into the region of the brain affected by traumatic injury. The second group received a sham procedure in which solution alone was infused into the brain with no implantation of stem cells.

At one and three months post-TBI (traumatic brain injury), the rats that had received SB632 transplants showed significantly better motor and neurological function and reduced brain tissue damage when compared to rats that had received no stem cells. These robust improvements despite the fact that the transplanted stem cells showed fair to poor survival that diminished over time.

Next, Borlongan’s laboratory workers examined the brain tissue of these rats. At three months post-TBI, the brains of transplanted rats showed massive cell proliferation and differentiation of stem cells into neuron-like cells in the area of injury. This was accompanied by a solid stream of stem cells that had migrated from the brain’s uninjured subventricular zone (where many new stem cells are formed) to the brain’s site of injury.

In contrast, those rats that had received solution alone showed limited proliferation and neural-commitment of stem cells, and only showed scattered migration to the site of brain injury and almost no expression of newly formed cells in the subventricular zone. Thus, without the addition of transplanted stem cells, the brain’s self-repair process appeared insufficient to mount a defense against the cascade of TBI-induced cell death.

Borlongan concluded that the transplanted stem cells create a neurovascular matrix that bridges the gap between the region in the brain where host neural stem cells arise and the site of injury. This pathway, or “biobridge,” ferries the newly emerging host cells to the specific place in the brain in need of repair, and helps them to promote functional recovery from traumatic brain injury.

Stem Cells Improve Cognition After Brain Injury


Research led by Charles Cox at the University of Texas Health Science Center has shown that stem cell therapy given during the critical time window after traumatic brain injury promotes lasting cognitive improvement. These experiments, which were published in the latest issue of the journal Stem Cells Translational Medicine, provide a pre-clinical model for experiments with larger animals.

After the brain has suffered a traumatic injury, there are few treatment options. Damage to the brain can be severe, and can also cause ongoing neurological impairment. Approximately half of all patients with severe head injuries need surgery to remove or repair ruptured blood vessels or bruised brain tissue.

In this work from Cox’s lab, stem cells from bone marrow known as multipotent adult progenitor cells (MAPCs) were used. MAPCs seem to be a subpopulation of mesenchymal stem cells, and they have a documented ability to reduce inflammation in mice immediately after traumatic brain injury. Unfortunately, no one has measured the ability of MAPCs to improve the condition of the brain over time.

Cox, Distinguished Professor of Pediatric Surgery at the UTHealth Medical School and in collaboration with the Children’s Fund, Inc., injected two groups of brain-injured mice with MAPCs two hours after injury and then once again 24 hours later. One group received a dose of 2 million cells per kilogram and the other a dose five times greater.

After four months, those mice that had received the stronger dose not only continued to have less inflammation, but they also showed significant gains in cognitive function. Laboratory examination of the brains of these rodents confirmed that those that had received the higher dose of MAPCs had better brain function than those that had received the lower dose.

According to Cox, “Based on our data, we saw improved spatial learning, improved motor deficits and fewer active antibodies in the mice that were given the stronger concentration of MAPCs.” Cox also indicated that this study indicates that intravenous injection of MAPCs might very well become a viable treatment for people with traumatic brain injury in the future.

Cox, who directs the Pediatric Surgical Translational Laboratories and Pediatric Program in Regenerative Medicine at UTHealth, is a leader in the field of autologous and blood cord stem cells for traumatic brain injury in children and adults. Results from a phase 1 study were published in a March 2011 issue of Neurosurgery, the journal of the Congress of Neurological Surgeons. Cox also directs the Pediatric Trauma Program at Children’s Memorial Hermann Hospital.

Regenerating Injured Kidneys with Exosomes from Human Umbilical Cord Mesenchymal Stem Cells


Zhou Y, Xu H, Xu W, Wang B, Wu H, Tao Y, Zhang B, Wang M, Mao F, Yan Y, Gao S, Gu H, Zhu W, Qian H: Exosomes released by human umbilical cord mesenchymal stem cells protect against cisplatin-induced renal oxidative stress and apoptosis in vivo and in vitro. Stem Cell Res Ther 2013, 4:34.

Ying Zhou and colleagues from Jiangsi University have provided helpful insights into how adult stem cell populations – in particular, mesenchymal stem cells (MSCs) isolated from human umbilical cord (hucMSCs) – are able to regulate tissue repair and regeneration. Adult stem cells, including MSCs from different sources, confer regenerative effects in animal models of disease and tissue injury. Many of these cells are also in phase I and II trials for limb ischemia, congestive heart failure, and acute myocardial infarction (Syed BA, Evans JB. Nat Rev Drug Discov 2013, 12:185–186).

Despite the documented healing capabilities of MSCs, in many cases, even though the implanted stem cells produce genuine, reproducible therapeutic effects, the presence of the transplanted stem cells in the regenerating tissue is not observed. These observations suggest that the predominant therapeutic effect of stem cells is conferred through the release of therapeutic factors. In fact, conditioned media from adult stem cell populations are able to improve ischemic damage to kidney and heart, which confirms the presence of factors released by stem cells in mediating tissue regeneration after injury (van Koppen A, et al., PLoS One 2012, 7:e38746; Timmers L, et al., Stem Cell Res 2007, 1:129–137). Additionally, the secretion of factors such as interleukin-10 (IL-10), indoleamine 2,3-dioxygenase (IDO), interleukin-1 receptor antagonist (IL-1Ra), transforming growth factor-beta 1 (TGF-β1), prostaglandin E2 (PGE2), and tumor necrosis factor-alpha-stimulated gene/protein 6 (TSG-6) has been implicated in conferring the anti-inflammatory effects of stem cells (Pittenger M: Cell Stem Cell 2009, 5:8–10). These observations cohere with the positive clinical effects of MSCs in treating Crohn’s disease and graft-versus-host disease (Caplan AI, Correa D. Cell Stem Cell 2011, 9:11–15).

Another stem cell population called muscle-derived stem/progenitor cells, which are related to MSCs, can also extend the life span of mice that have the equivalent of an aging disease called progeria. These muscle-derived stem/progenitor cells work through a paracrine mechanism (i.e. the release of locally acting substances from cells; see Lavasani M, et al., Nat Commun 2012, 3:608). However, it is unclear what factors released by functional stem cells are important for facilitating tissue regeneration after injury, disease, or aging and the precise mechanism through which these factors exert their effects. Recently, several groups have demonstrated the potent therapeutic activity of small vesicles called exosomes that are released by stem cells (Gatti S, et al., Nephrol Dial Transplant 2011, 26:1474–1483; Bruno S, et al., PLoS One 2012, 7:e33115; Lai RC, et al., Regen Med 2013, 8:197–209; Lee C, et al., Circulation 2012, 126:2601–2611; Li T, et al., Stem Cells Dev 2013, 22:845–854). Exosomes are a type of membrane vesicle with a diameter of 30 to 100 nm released by most cell types, including stem cells. They are formed by the inverse budding of the multivesicular bodies and are released from cells upon fusion of multivesicular bodies with the cell membrane (Stoorvogel W, et al., Traffic 2002, 3:321–330).

Exosomes are distinct from larger vesicles, termed ectosomes, which are released by shedding from the cell membrane. The protein content of exosomes depends on the cells that release them, but they tend to be enriched in certain molecules, including adhesion molecules, membrane trafficking molecules, cytoskeleton molecules, heat-shock proteins, cytoplasmic enzymes, and signal transduction proteins. Importantly, exosomes also contain functional mRNA and microRNA molecules. The role of exosomes in vivo is hypothesized to be for cell-to-cell communication, transferring proteins and RNAs between cells both locally and at a distance.

To examine the regenerative effects of MSCs derived from human umbilical cord, Zhou and colleagues used a rat model of acute kidney toxicity induced by treatment with the anti-cancer drug cisplatin. After treatment with cisplatin, rats show increases in blood urea nitrogen and creatinine levels (a sign of kidney dysfunction) and increases in apoptosis, necrosis, and oxidative stress in the kidney. If exosomes purified from hucMSCs, termed hucMSC-ex are injected underneath the renal capsule into the kidney, these indices of acute kidney injury decrease. In cell culture, huc-MSC-exs promote proliferation of rat renal tubular epithelial cells in culture. These results suggest that hucMSC-exs can reduce oxidative stress and programmed cell death, and promote proliferation. What is not clear is how these exosomes pull this off. Zhou and colleagues provide evidence that hucMSC-ex can reduce levels of the pro-death protein Bax and increase the pro-survival Bcl-2 protein levels in the kidney to increase cell survival and stimulate Erk1/2 to increase cell proliferation.

Another research group has reported roles for miRNAs and antioxidant proteins contained in stem cell-derived exosomes for repair of damaged renal and cardiac tissue (Cantaluppi V, et al., Kidney Int 2012, 82:412–427). In addition, MSC exosome-mediated delivery of glycolytic enzymes (the pathway that degrades sugar) to complement the ATP deficit in ischemic tissues was recently reported to play an important role in repairing the ischemic heart (Lai RC, et al., Stem Cell Res 2010, 4:214–222). Clearly, stem cell exosomes contain many factors, including proteins and microRNAs that can contribute to improving the pathology of damaged tissues.

The significance of the results of Zhou and colleagues and others is that stem cells may not need to be used clinically to treat diseased or injured tissue directly. Instead, exosomes released from the stem cells, which can be rapidly isolated by centrifugation, could be administered easily without the safety concerns of aberrant stem cell differentiation, transformation, or recognition by the immune system. Also, given that human umbilical cord exosomes are therapeutic in a rat model of acute kidney injury, it is likely that stem cell exosomes from a donor (allogeneic exosomes) would be effective in clinical studies without side effects.

These are fabulously interesting results, but Zhou and colleagues have also succeeded in raising several important questions. For example: What are the key pathways targeted by stem cell exosomes to regenerate injured renal and cardiac tissue? Are other tissues as susceptible to the therapeutic effects of stem cell exosomes? Do all stem cells release similar therapeutic vesicles, or do certain stem cells release vesicles targeting only specific tissue and regulate tissue-specific pathways? How can the therapeutic activity of stem cell exosomes be increased? What is the best source of therapeutic stem cell exosomes?

Despite these important remaining questions, the demonstration that hucMSCderived exosomes block oxidative stress, prevent cell death, and increase cell proliferation in the kidney makes stem cell-derived exosomes an attractive therapeutic alternative to stem cell transplantation.

See Dorronsoro and Robbins: Regenerating the injured kidney with human umbilical cord mesenchymal stem cell-derived exosomes. Stem Cell Research & Therapy 2013 4:39.