Stem Cell Therapy Might Improve Brain Function of Traumatic Brains Injury Patients


Accidents happen and sometimes really bad accidents happen; especially if they injure your head.  Traumatic brain injuries or TBIs can result from automobile accidents, explosions or other events that result from severe blows to the head.  TBIs  an adversely affect a patient and his/her family for long periods of time.  TBI patients can experience cognitive deficits that prevent them from thinking or speaking straight, and sensory deficits that prevent them from seeing, hearing or smelling properly.  Psychological problems can also result.  Essentially, TBIs represent a major challenge for modern medicine.

According to data from the Centers for Disease Control (CDC), 1.7 million Americans suffer from TBIs each year (of varying severity).  Of these, 275,000 are hospitalized for their injuries and approximately 52,000 of these patients die from their injuries.  In fact, TBIs contribute to one-third of all injury-related deaths in the United States each year.  More than 6.5 million patients are burdened by the deleterious effects of TBIs, and this leads to an economic burden of approximately $60 billion each year.

Currently, treatments for TBI are few and far between.  Neurosurgeons can use surgery to repair damaged blood vessels and tissues, and diminish swelling in the brain.  Beyond these rather invasive techniques, the options for clinicians are poor.

A new study by Charles S. Cox, professor of Pediatric Surgery and co-director of the Memorial Hermann Red Duke Trauma Institute, and his colleagues suggest that stem cell treatments might benefit TBI patients.  The results of this study were published in the journal Stem Cells.

This study enrolled 25 TBI patients.  Five of them received no treatment and served as controls, but the remaining 20 received gradually increasing dosages of their own bone marrow stem cells.  The harvesting, processing and infusion of the bone marrow cells occurred within 48 hours of injury.  Functional and cognitive results were measured with standard tests and brain imaging with magnetic resonance imaging and diffusion tensor imaging.

This work is an extension of extensive preclinical work done by Cox and his coworkers in laboratory animals and a phase I study that established that such stem cell transplantation are safe for human patients.  The implanted stem cells seem to quell brain inflammation and lessen the damage to the brain by the TBI.

Despite the fact that those TBI patients who received the stem cell treatments had greater degrees of brain damage, the treatment group showed better structural preservation of the brain and better functional outcomes than the control group.  Of particular interest was the decrease in indicators of inflammation as a result of the bone marrow cell-based infusions.

Cox said of this trial, “The data derived from this trial moves beyond just testing safety of this approach.”  He continued:  “We now have a hint of a treatment effect that mirrors our pre-clinical work, and were are now pursuing this approach in a phase IIb clinical trial sponsored by the Joint Warfighter Program within the US Army Medical Research Acquisition Activity, as well as our ongoing phase IIb pediatric severe TBI clinical trial; both using the same autonomous cell therapy.”

This an exciting study, but it is a small study.  While the safety of this procedure has been established, the precise dosage and long-term benefits will require further examination.  However it is a fine start to what may become the flowering of new strategies to treat TBI patients.

Bone Marrow Mesenchymal Stem Cells Spontaneously Make Cartilage After Blockage of VEGF Signaling


Bone marrow-derived mesenchymal stem cells (MSCs) can be induced to make cartilage by incubating the cells with particular growth factors.  Unfortunately, batches of MSCs show respectable variability from patient-to-patient.  Therefore the growth factor-dependent method suffers from poor efficacy, limited reproducibility from batch-to-batch, and the cell types that are induced are not always terribly stable.  Finding a better way to make cartilage would certainly be a welcome addition to regenerative treatments,

Cartilage that coats the ends of bones is known as articulate cartilage, and articular cartilage lacks blood vessels.  Therefore, is it possible that inhibiting blood vessel formation could conveniently push MSCs to differentiate into cartilage-making chondrocytes?

A new paper by Ivan Martin and Andrea Basil from the University Hospital Basel and their colleagues have used this very strategy to induce cartilage formation in MSCs from bone marrow.

Martin and others isolated MSCs from bone marrow aspirates from human donors.  These cultured human MSCs were then genetically engineered with modified viruses to express a receptor for soluble vascular endothelial growth factor (VEGF) that binds this growth factor, but fails to induce any intracellular signals.  Such a receptor that binds the growth factor but does not induce any biological effects is called a “decoy receptor,” and decoy receptors efficiently sequester or vacuum up all the endogenous VEGF.  VEGF is the major blood vessel-inducing growth factor and it is heavily expressed during development, by cancer cells, and during healing.

After expressing the decoy VEGF receptor in these human MSCs, these genetically engineered cells were grown on collagen sponges and then implanted in immunodeficient mice.  If the implanted MSCs were not genetically engineered to express decoy VEGF receptors, they induced for formation of vascularized fibrous tissue.  However, the implantation of genetically engineered MSCs that expressed the decoy VEGF receptor efficiently and reproducibly differentiated into chondrocytes and formed hyaline cartilage. This is significant because headline cartilage is the very type of cartilage found at articular surfaces where the ends of bones come together to form joints.

In vivo chondrogenesis. Histological staining with Safranin-O for glycosaminoglycans and immunohistochemistry for type II collagen of engineered tissue generated by naïve (control) or sFlk-1 MSCs after 4 (A) or 12 (B) weeks in vivo. Fluorescence staining with DAPI (in blue) and a specific anti-human nuclei antibody (in red) of constructs generated by control or sFlk-1 MSCs after 4 (A) or 12 (B) weeks in vivo. Scale bar = 100 µm. Abbreviations: DAPI, 4′,6-diamidino-2-phenylindole; MSC, bone marrow-derived mesenchymal stromal/stem cell.
In vivo chondrogenesis. Histological staining with Safranin-O for glycosaminoglycans and immunohistochemistry for type II collagen of engineered tissue generated by naïve (control) or sFlk-1 MSCs after 4 (A) or 12 (B) weeks in vivo. Fluorescence staining with DAPI (in blue) and a specific anti-human nuclei antibody (in red) of constructs generated by control or sFlk-1 MSCs after 4 (A) or 12 (B) weeks in vivo. Scale bar = 100 µm. Abbreviations: DAPI, 4′,6-diamidino-2-phenylindole; MSC, bone marrow-derived mesenchymal stromal/stem cell.

This articular cartilage was quite stable and showed no signs of undergoing the chondrocytes enlargement found in terminally differentiated cartilage that is ready to form bone.  This stability was maintained for up to 12 weeks.

In vivo cartilage stability. Immunohistochemistry for type X collagen, BSP, and MMP-13 on sections of hypertrophic cartilage generated in vitro by MSCs (as a positive control) and on sections of the cartilaginous constructs generated in vivo by sFlk1 MSCs 12 weeks after implantation. Scale bar = 50 µm. Abbreviations: BSP, bone sialoprotein; MMP-13, metalloproteinase-13; MSC, bone marrow-derived mesenchymal stromal/stem cell.
In vivo cartilage stability. Immunohistochemistry for type X collagen, BSP, and MMP-13 on sections of hypertrophic cartilage generated in vitro by MSCs (as a positive control) and on sections of the cartilaginous constructs generated in vivo by sFlk1 MSCs 12 weeks after implantation. Scale bar = 50 µm. Abbreviations: BSP, bone sialoprotein; MMP-13, metalloproteinase-13; MSC, bone marrow-derived mesenchymal stromal/stem cell.

Why did inhibition of VEGF signaling induce cartilage?  Inhibition of angiogenesis induced low oxygen tensions, which activated a growth factor called transforming growth factor-β.  Activation of the TGF-beta pathway robustly enhanced the formation of articular cartilage.

In vitro chondrogenesis at different oxygen tensions. Histological staining with Safranin-O and immunohistochemistry for type II collagen on constructs generated in vitro by naïve MSC cultured with (A) or without (B) TGFβ3 supplementation at 2% or 20% of oxygen tension. Scale bar = 50 µm. Expression levels of the mRNA for type II and X collagen, Gremlin-1, IHH TGFβ1 were quantified in pellets generated by naïve bone marrow-derived mesenchymal stromal/stem cells (C, D) cultured in the two different oxygen tensions. ∆Ct values were normalized to expression of the GAPDH housekeeping gene, and results are shown as mean ± SD (n = 6 samples/group from 3 independent experiments). ∗, p < .05, ∗∗∗, p < .001. Abbreviations: GAPDH, glyceraldehyde-3-phosphate dehydrogenase; IHH, Indian hedgehog; TGFβ, transforming grown factor-β.
In vitro chondrogenesis at different oxygen tensions. Histological staining with Safranin-O and immunohistochemistry for type II collagen on constructs generated in vitro by naïve MSC cultured with (A) or without (B) TGFβ3 supplementation at 2% or 20% of oxygen tension. Scale bar = 50 µm. Expression levels of the mRNA for type II and X collagen, Gremlin-1, IHH TGFβ1 were quantified in pellets generated by naïve bone marrow-derived mesenchymal stromal/stem cells (C, D) cultured in the two different oxygen tensions. ∆Ct values were normalized to expression of the GAPDH housekeeping gene, and results are shown as mean ± SD (n = 6 samples/group from 3 independent experiments). ∗, p < .05, ∗∗∗, p < .001. Abbreviations: GAPDH, glyceraldehyde-3-phosphate dehydrogenase; IHH, Indian hedgehog; TGFβ, transforming grown factor-β.

Cartilage formation from MSCs was induced by blocking VEGF-mediated angiogenesis.  These results represent a remarkable advance in cartilage formation that can be used for regenerative treatments.  This cartilage formation was spontaneous and efficient and if it can be carried out with VEGF-inhibiting drugs rather than genetic engineering techniques, then we might have a transferable technique for making cartilage in the laboratory to treat osteoarthritis and other joint-based maladies.  Clinical trials will be required, but this is certainly an auspicious start.

The Amino Acid Valine Helps Maintain Hematopoietic Stem Cell Niches


Hematopoietic stem cells (HSCs) populate our bone marrow and divide throughout our lifetimes to provide the red and white blood cells we need to live. However, during normal, healthy times, only particular HSCs are hard at work dividing and making new blood cells. The remaining HSCs are maintained in a protective dormant state. However, in response to blood loss or physiological stress of some sort, dormant HSCs must wake from their “slumbers” and begin dividing to make the needed blood cells. Such conditions, it turns out, can cause HSCs to experience a good deal of damage to their genomes. A paper that was published in Nature last year by Walter Dagmar and colleagues (Vol 520: pp. 549) showed that repeatedly subjecting mice to conditions that required the activation of dormant HSCs (in this case they injected the mice with polyinosinic:polycytidylic acid or pI:pC to mimic a viral infection and induce a type I interferon response) resulted in the eventual collapse of the bone marrow’s ability to produce new blood cells. The awakened HSCs accumulated such large quantities of DNA damage, that they were no longer able to divide and produce viable progeny. How then can HSCs maintain the integrity of their genomes while still dividing and making new blood cells?

The answer to this question is not completely clear, but a new paper in the December 2 edition of Science magazine provides new insights into HSC physiology and function. This paper by Yuki Taya and others, working in the laboratories of Hiromitsu Nakauchi at the Institute for Stem Cell Biology and Regenerative Medicine at Stanford University School of Medicine, and Satoshi Yamazaki from the University of Tokyo, has shown that amino acid metabolism plays a vital role in HSC maintenance. As it turns out, the amino acid concentrations in bone marrow are approximately 100-fold higher than the concentrations of these same amino acids in circulating blood. Taya and others reasoned that such high amino acid concentrations must exist for reasons other than protein synthesis. Therefore, they designed dietary regimens that depleted mice for specific amino acids. Sure enough, when mice were fed valine-depleted diets, the HSCs of those mice lost their ability to repopulate the bone marrow.

Valine
Valine

After only two weeks of valine depletion, several nooks and crannies of the bone marrow – so-called stem cell “niches” – were devoid of HSCs. The bone marrow of such mice was easily reconstituted with HSCs from donor mice without the need for radiation or chemical ablation treatments.

Taya and others found that vascular endothelial stromal cells in the bone marrow secrete valine and that this secreted valine (which, by the way, is a branched-chain amino acid) is integral for maintaining HSC niches.

The excitement surrounding this finding is plain, since using harsh chemicals or radiation to destroy the bone marrow (a procedure known as “myeloablation”) causes premature ageing, infertility, lousy overall health, and other rather unpleasant side effects. Therefore, finding a “kinder, gentler” way to reconstitute the bone marrow would certainly be welcomed by patients and their physicians. However, valine depletion, even though it does not affect sterility, did cause 50% of the mice to die once valine was restored to the diet. This is due to a phenomenon known as the “refeeding effect” which has also been observed in human patients. Such side effects could probably be prevented by gradually returning valine to the diet. Taya and others also showed that cultured human HSCs required valine and another branched-chain amino acid, leucine. Since both leucine and valine are metabolized to alpha-ketoglutatate, which is used as a substrate for DNA-modifying enzymes, these amino acids might exert their effects through epigenetic modifications to the genome.

Alpha-ketoglutarate
Alpha-ketoglutarate

More work is needed in this area, but the Taya paper is a welcomed finding to a vitally important field.

Inhibition of AKT Kinase Increases Umbilical Cord Blood Growth in Culture and Engraftment in Mice


Dr. Yan Liu from the Department of Pediatrics and the Herman B Wells Center for Pediatric Research at the Indiana University School of Medicine in Indianapolis, Indiana and his colleagues have increased the engraftment efficiency of umbilical cord hematopoietic (blood cell-making) stem cells in immunodeficient mice. The technique developed by Lui and his colleagues is simple and increases the proliferation of umbilical cord blood hematopoietic stem cells (UCB-HSCs) in culture, which potentially solves several long-standing problems with umbilical cord blood transplantation.

Umbilical cord blood has been used in the clinic for more than 40 years in hematopoietic stem cell transplantation therapies to treat patients with bone marrow diseases or to reconstitute the bone of those cancer patients who had to have theirs wiped out to cure their leukemia or lymphoma.

One of the problems with umbilical cord blood transplantations, however, is the small amount of material in a typical cord blood collection and, therefore, the small number of hematopoietic stem cells (HSCs) available for transplantation. To ameliorate these shortcomings, hematologists will transplant more than one lot of cord blood (a so-called “double umbilical cord blood transplantation”), which, unfortunately, also increases the risk of immunological rejection (so-called Graft Versus Host response).

A second strategy to get around the low numbers of UCB-HSCs is to expand them in culture, which has proven difficult. However, some experiments have given us more than enough hope to suspect this this is a feasible option (see Flores-Guzmán P, et al., Stem Cells Transl Med. 2013 Nov;2(11):830-8; Bari S., et al., Biol Blood Marrow Transplant. 2015 Jun;21(6):1008-1; Pineault N, Abu-Khader A. Exp Hematol. 2015 Jul;43(7):498-513).

Dr. Lui and his coworkers wanted to examine the role of the signaling protein AKT (also known and protein kinase B) in UCB-HSC expansion in culture. To this end, they used silencing RNAs to knock-down AKT gene expression in cultured UCB-HSCs. AKT knock-down enhanced UCB-HSC quiescence and growth in culture. In a separate experiment, Lui and others treated human UCB-HSCs (so-called CD34+ cells) with a chemical that specifically inhibits AKT activity. Then they subjected these cells to a battery of tests in culture and in laboratory mice.

The results were astounding.  Treatment of human UCB-HSCs did not affect the identity of the HSCs and enhanced their ability to form isolated colonies in cell culture growth tests known as “replating assays.”  Additionally, the short-term inhibition of AKT with drugs also enhanced the ability of UBC-HSCs to repopulate the bone marrow of immunodeficient mice.

ubc-hsc-engraftment-improved-with-akt-inhibition

In summary, inhibition of AKT increases human UCB-HSC quiescence, growth potential, and engraftment in laboratory mice.

These interesting pre-clinical results suggest that AKT inhibitor can increase the expansion of UCB-HSCs in culture and potential increase their tendency of these cells to engraft in patients.

Gamida Cell Announces First Patient with Sickle Cell Disease Transplanted in Phase 1/2 Study of CordIn™ as the Sole Graft Source


An Israeli regenerative therapy company called Gamida Cell specializes in cellular and immune therapies to treat cancer and rare (“orphan”) genetic diseases. Gamida Cell’s main product is called NiCord, which provides patients who need new blood-making stem cells in their bone marrow an alternative to a bone marrow transplant. NiCord is umbilical cord blood that has been expanded in culture. In clinical trials to date, NiCord has rapidly engrafted into patients and the clinical outcomes of NiCord transplantation seem to be comparable to transplantation of peripheral blood.

Gamida Cell’s two products, NiCord and CordIn, as well as some other products under development utilize the company’s proprietary NAM platform technology to expand umbilical cord cells. The NAM platform technology has the remarkable capacity to preserve and enhance the functionality of hematopoietic stem cells from umbilical cord blood. CordIn is an experimental therapy for those rare non-malignant diseases in which bone marrow transplantation is the only currently available cure.

Gamida Cell has recently announced that the first patient with sickle cell disease (SCD) has been transplanted with their CordIn product.  Mark Walters, MD, Director of the Blood and Marrow Transplantation (BMT) Program is the Principal Investigator of this clinical trial. The patient received their transplant at UCSF Benioff Children’s Hospital Oakland.

CordIn, as previously mentioned, is an experimental therapy for rare non-malignant diseases, including hemoglobinopathies such as Sickel Cell Disease and thalassemia, bone marrow failure syndromes such as aplastic anemia, genetic metabolic diseases and refractory autoimmune diseases. CordIn potentially addresses a presently unmet medical need.

“The successful enrollment and transplantation of our first SCD patient with CordIn as a single graft marks an important milestone in our clinical development program. We are eager to demonstrate the potential of CordIn as a transplantation solution to cure SCD and to broaden accessibility to patients with rare genetic diseases in need of bone marrow transplantation,” said Gamida Cell CEO Dr. Yael Margolin. “In the first Phase 1/2 study with SCD, the expanded graft was transplanted along with a non-manipulated umbilical cord blood unit in a double graft configuration. In the second phase 1/2 study we updated the protocol from our first Phase 1/2 study so that patients would be transplanted with CordIn as a standalone graft, which is expanded from one full umbilical cord blood unit and enriched with stem cells using the company’s proprietary NAM technology.”

Somewhere in the vicinity of 100,000 patients in the U.S suffer from SCD; and around 200,000 patients suffer from thalassemia, globally. The financial burden of treating these patients over their lifetime is estimated at $8-9M. Bone marrow transplantation is the only clinically established cure for SCD, but only a few hundred SCD patients have actually received a bone marrow transplant in the last ten years, since most patients were not successful in finding a suitable match. Unrelated cord blood could be available for most of the patients eligible for transplantation, but, unfortunately, the rate of successful engraftment of un-expanded cord blood in these patients is low. Therefore, cord blood is usually not considered for SCD patients. Without a transplant, these patients suffer from very high morbidity and low quality of life.

Eight patients with SCD were transplanted in the first Phase 1/2 study performed in a double graft configuration. This study is still ongoing. Preliminary data from the first study will be summarized and published later this year. A Phase 1/2 of CordIn for the treatment of patients with aplastic anemia will commence later this year.

Genetic Switch to Making More Blood-Making Stem Cells Found


A coalition of stem cell scientists, co-led in Canada by Dr. John Dick, Senior Scientist, Princess Margaret Cancer Centre, University Health Network (UHN) and Professor, Department of Molecular Genetics, University of Toronto, and in the Netherlands by Dr. Gerald de Haan, Scientific Co-Director, European Institute for the Biology of Ageing, University Medical Centre Groningen, the Netherlands, have uncovered a genetic switch that can potentially increase the supply of stem cells for cancer patients who need transplantation therapy to fight their disease.

Their findings were published in the journal Cell Stem Cell and constitute proof-of-concept experiments that may provide a viable new approach to making more stem cells from umbilical cord blood.

“Stem cells are rare in cord blood and often there are not enough present in a typical collection to be useful for human transplantation. The goal is to find ways to make more of them and enable more patients to make use of blood stem cell therapy,” says Dr. Dick. “Our discovery shows a method that could be harnessed over the long-term into a clinical therapy and we could take advantage of cord blood being collected in various public banks that are now growing across the country.”

Currently, all patients who require stem cell transplants must be matched to an adult donor. The donor and the recipient must share a common set of cell surface proteins called “human leukocyte antigens” HLAs. HLAs are found on the surfaces of all nucleated cells in our bodies and these proteins are encoded by a cluster of genes called the “Major Histocompatibility Complex,” (MHC) which is found on chromosome six.

Map of MHC

There are two main types of MHC genes: Class I and Class II.

MHC Functions

Class I MHC contains three genes (HLA-A, B, and C). The three proteins encoded by these genes, HLA-A, -B, & -C, are found on the surfaces of almost all cells in our bodies. The exceptions are red blood cells and platelets, which do not have nuclei. Class II MHC genes consist of HLA-DR, DQ, and DP, and the proteins encoded by these genes are exclusive found on the surfaces of immune cells called “antigen-presenting cells” (includes macrophages, dendritic cells and B cells). Antigen-presenting cells recognize foreign substances in our bodies, grab them and, if you will, hold them up for everyone to see. The cells that usually respond to antigen presentation are immune cells called “T-cells.” T-cells are equipped with an antigen receptor that only binds antigens when those antigens are complexed with HLA proteins.

If you are given cells from another person who is genetically distinct from you, the HLA proteins on the surfaces of those cells are recognized by antigen-presenting cells as foreign substances. The antigen-presenting cells will them present pieces of the foreign HLA proteins on their surfaces, and T-cells will be sensitized to those proteins. These T-cells will them attack and destroy any cells in your body that have those foreign HLA proteins. This is the basis of transplant rejection and is the main reason transplant patients must continue to take drugs that prevent their T-cells from recognizing foreign HLA proteins as foreign.

When it comes to bone marrow transplantations, patients can almost never find a donor whose HLA surface proteins match perfectly. However, if the HLA proteins of the donor are too different from those of the recipient, then the cells from the bone marrow transplant attack the recipient’s cells and destroy them. This is called “Graft versus Host Disease” (GVHD). The inability of leukemia and lymphoma and other patients to receive bone marrow transplants is the unavailability of matching bone marrow. Globally, many thousands of patients are unable to get stem cell transplants needed to combat blood cancers such as leukemia because there is no donor match.

“About 40,000 people receive stem cell transplants each year, but that represents only about one-third of the patients who require this therapy,” says Dr. Dick. “That’s why there is a big push in research to explore cord blood as a source because it is readily available and increases the opportunity to find tissue matches. The key is to expand stem cells from cord blood to make many more samples available to meet this need. And we’re making progress.”

Umbilical cord blood, however, is different from adult bone marrow. The cells in umbilical cord blood are more immature and not nearly as likely to generate GVHD. Therefore, less perfect HLA matches can be used to treat patients in need of a bone marrow transplant. Unfortunately, umbilical cord blood has the drawback of have far fewer stem cells than adult bone marrow. If the number of blood-making (hematopoietic) stem cells in umbilical cord blood can be increased, then umbilical cord blood would become even more useful from a clinical perspective.

There has been a good deal of research into expanding the number of stem cells present in cord blood, the Dick/de Haan teams took a different approach. When a stem cell divides it produces a large number of “progenitor cells” that retain key properties of being able to develop into every one of the 10 mature blood cell types. These progenitor cells, however, have lost the critical ability to self-renew.

Dick and his colleagues analyzed mouse and human models of blood development, and they discovered that a microRNA called miR-125a is a genetic switch that is on in stem cells and controls self-renewal, but gets turned off in the progenitor cells.

“Our work shows that if we artificially throw the switch on in those downstream cells, we can endow them with stemness and they basically become stem cells and can be maintained over the long-term,” says Dr. Dick.

In their paper, Dick and de Haan showed that forced expression of miR-125 increases the number of hematopoietic stem cells in a living animal. Also, miR-125 induces stem cell potential in murine and human progenitor cells, and represses, among others, targets of the MAP kinase signaling pathway, which is important in differentiation of cells away from the stem cell fate. Furthermore, since miR-125 function and targets are conserved in human and mouse, what works in mice might very well work in human patients.

graphical abstract CSC_v9

This is proof-of-concept paper – no human trials have been conducted to date, but these data may be the beginnings of making more stem cells from banked cord blood to cure a variety of blood-based conditions.

Here’s to hoping.

C-Cure Shows Positive Trends in Phase 3 Trial but Fails to Meet Primary Endpoints


Celyad has pioneered a stem cell treatment for the heart called C-Cure. C-Cure consists of bone marrow stem cells that are isolated from a bone marrow aspiration that are then treated with a proprietary concoction that drives the cells to become cardiac progenitor cells, After this treatment, the cells are administered to the patient by means of a catheter where they will hopefully regenerate dead heart muscle tissue, make new blood vessels to replace clogged and dead blood vessels, and also smooth muscle cells to regulate the diameter of the newly-formed blood vessels.

The first clinical trial for C-Cure was announced in the Journal of the American College of Cardiology in June 2013. At this time, Celyad reported in their published data that all the mesenchymal stem cells (MSCs) had been successfully primed with their cocktails and successfully delivered to each patient. The desired cell dose was achieved in 75% of patients in cell delivery without complications occurred in 100% of cases. Fortunately, there were incidents of increased cardiac or systemic toxicity induced by the therapy.

Patients also showed some improvements. For example, left ventricular ejection fraction was improved by cell therapy (from 27.5 ± 1.0% to 34.5 ± 1.1%) versus standard of care alone (from 27.8 ± 2.0% to 28.0 ± 1.8%, p = 0.0001) and was associated with a reduction in left ventricular end-systolic volume (−24.8 ± 3.0 ml vs. −8.8 ± 3.9 ml, p = 0.001). Patients was received MSC therapy also improved their 6-min walk distance (+62 ± 18 m vs. −15 ± 20 m, p = 0.01) and had a superior composite clinical score encompassing cardiac parameters in tandem with New York Heart Association functional class, quality of life, physical performance, hospitalization, and event-free survival. The initial trial examined 13 control patients who received standard care and 20 patients who received their own MSCs and followed them for 2 years.

The strategy surrounding C-Cure is based on preclinical experiments in laboratory mice in which animals that had suffered heart attacks were treated with human MSCs that had been isolated from volunteers and pretreated with a cocktail that consisted of transforming growth factor-beta1, bone morphogenetic protein-4, activin A, retinoic acid, insulin-like growth factor-1, fibroblast growth factor-2, alpha-thrombin, and interleukin-6. This cocktail apparently drove the cells to form a heart-like fate. Then the cocktail-treated MSCs were implanted into the hearts of the mice and in the words of the paper’s abstract, the cells “achieved superior functional and structural benefit without adverse side effects. Engraftment into murine hearts was associated with increased human-specific nuclear, sarcomeric, and gap junction content along with induction of myocardial cell cycle activity.”. must say that I did not see definitive proof in this paper that the implanted cells actually formed new myocardium as opposed to inducing native cardiac stem cell population to form new myocardial cells.

This present trial is a Phase 3 clinical trial and it examined changes in patient mortality, morbidity, quality of life, six-minute walk test, and left ventricular structure and function at nine months after the treatment was given, The trial recruited 271 evaluable patients with chronic advanced symptomatic heart failure in 12 different countries in Europe and Israel. Like the trial before it, it was double blinded, placebo controlled.

First the good news: the procedure was well tolerated with no safety concerns.

The bad news was that a statistically-significant difference between the control group and treatment group was not observed 39 weeks after treatment. There is a silver lining to all this though: a positive trend was seen across all treatment groups. More interestingly, the primary endpoint was met (p=0.015) for a subset of the patients treated with their own MSCs. This subset represents 60% of the population of the CHART-1 study (baseline End Diastolic Volume (EDV) segmentation), which is pretty significant subset of the subject group. These patients showed less mortality and worsening of heart failure, better quality of life, an improved 6-minute walk test, end systolic volume and an improved ejection fraction.

On the strength of these data, Celyad thinks that this 60^ might represent the patient population for whom C-Cure is a viable treatment. What remains is to determine exactly who those patients are, the nature of their disease, and how much patients might be identified.

Dr. Christian Homsy, CEO of Celyad, commented: “For the first time in a randomized, double-blind, controlled, Phase III cell therapy study, a positive effect, consistent across all parameters tested, was observed for a substantial, clearly definable, group of heart failure patients.

CHART-1 has allowed us to better define the patient population that would benefit from C-Cure®. We are excited by the prospects for C-Cure® as a new potential treatment option for a highly relevant heart failure population. We are confident that the results will generate interest from potential partners that could accelerate the development and commercialization of C-Cure®.”

Prof. Jozef Bartunek, CHART-1 principal co-investigator, said: “This pioneering study has contributed greatly to our understanding of heart failure disease and the place of regenerative medicine in its management. The results seen for a large clinically relevant number of the patients are ground breaking. We look forward to completing the full analysis and making the data available to the medical community at ESC.

On behalf of the CHART 1 steering committee we wish to thank the patients and families who were enrolled in the study as well as all the physicians and medical teams that made this study possible.”

Prof. Gerasimos Filippatos, Immediate Past-President of the Heart Failure Association of the European Society of Cardiology, member of the CHART-1 dissemination committee, said, “The CHART-1 results have identified a well-defined group of patients with symptomatic heart failure despite optimal therapy. Those patients are a large subset of the heart failure population and present specific therapeutic challenges. The outcome of CHART-1 indicate those patients could benefit from this therapy”.

The Company will use their CHART-1 results as the foundation of their CHART-2 US trial, which will test the target patient group with C-CURE. Celyad is also in the process of seeking partnerships to accelerate further development and commercialization of C-Cure®.

Do C-CURE cells make new heart muscle cells?  Count me skeptical.,  Just because cells form something that looks like cardiac cells in culture is no indication that they form tried and true heart muscle cells.  This is especially true, since bone marrow-based cells lack the calcium handling machinery of heart muscle cells and until someone definitely shows that bone marrow cells can be transdiferentiated into cells that possess the calcium handling proteins of heart muscle cells, I will remain skeptical,

Having said that, this is a very interesting clinical trial despite the fact that it failed to meet its primary endpoints.  Further work might even make more of it.  Here’s to hoping.

Autologous Stem Cell Transplantation With Complete Ablation of Bone Marrow Delays Progression of Multiple Sclerosis in Small Phase 2 Trial


Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. Around 2 million people, worldwide, suffer from MS. MS results from the patient’s immune system attacking the myelin sheath that surrounds nerve axons. These constant and relentless attacks upon the myelin sheath causes “demyelination,” resulting in loss of the sensory and motor function.

Treatment usually required the use of drugs that suppress the immune response. Some of these drugs work better than others, while other patients have forms of MS that do not respond to common MS treatment.

A new report published in the Lancet, has shown that chemotherapy followed by autologous hematopoietic stem cell transplantation (aHSCT) can completely halt clinical relapses of MS and prevent the development of new brain lesions in 23 of 24 MS patients. Patients who participated in this study experienced a prolonged period without the need for ongoing medication. Eight of the 23 patients had a sustained improvement in their disability 7.5 years after treatment. This is the first treatment to produce this level of disease control or neurological recovery from MS, but, unfortunately, treatment related risks limit its widespread use.

There are a few specialist centers that offer MS patients aHSCT. This treatment involves harvesting bone marrow stem cells from the patient, and then employing chemotherapy to suppress the patient’s immune system and essentially partially wipe it out. The isolated bone marrow is then reintroduced into the blood stream to “reset” the immune system and stop it attacking the body. However, a respectable percentage of MS patients relapse after these treatments. Therefore, these treatments must be refined and tweaked to improve their efficacy.

Drs Harold L Atkins and Mark S Freedman from The Ottawa Hospital and the University of Ottawa, Ottawa, Canada, respectively, and their colleagues, tested if complete destruction, rather than suppression, of the immune system during aHSCT could reduce the relapse rate in patients and increase the long-term rates of disease remission. They enrolled 24 patients aged 18-50 from three Canadian hospitals. All of these subjects had previously undergone standard immunosuppressive therapy, but these treatments had failed to control their MS. These patients all had poor prognosis and their disability ranged from moderate to requiring a walking aid to walk 100 meters (according to their Expanded Disability Status Scale or EDSS score).

Adkins and Freeman and their coworkers used a chemotherapy regimen of busulfan, cyclophosphamide and rabbit anti-thymocyte globulin to wipe out the patient’s bone marrow. Atkins explained that this treatment is “similar to that used in other trials, except our protocol uses stronger chemotherapy and removes immune cells from the stem cell graft product. The chemotherapy we use is very effective at crossing the blood-brain barrier and this could help eliminate the damaging immune cells from the central nervous system.” After being treated with chemotherapy regimen, the patients’ bone marrow was reconstituted with their previously isolated bone marrow.

This study’s primary outcome was activity-free survival at 3 years, using EDSS scores as the means of measuring MS progression, in addition to scanning for brain lesions, and assessing MS symptoms.

Of the 24 patients enrolled, one (4%) died from liver failure and sepsis caused by the chemotherapy. In the 23 surviving patients, prior to treatment, patients experienced 1.2 relapses per year on average, but after aHSCT, no relapses occurred during the follow-up period (between 4 and 13 years). These clinical outcomes were nicely complemented by an absence of newly detected brain lesions (as assessed by MRI images taken after the treatment). Initially, 24 MRI scans of the brains of all 24 subjects revealed 93 brain lesions, and after the treatment only one of the 327 scans showed a new lesion.

Despite the exciting success of this clinical trial, Freedman emphasized the need to interpret these results with caution: “The sample size of 24 patients is very small, and no control group was used for comparison with the treatment group. Larger clinical trials will be important to confirm these results. Since this is an aggressive treatment, the potential benefits should be weighed against the risks of serious complications associated with aHSCT, and this treatment should only be offered in specialist centers experienced both in multiple sclerosis treatment and stem cell therapy, or as part of a clinical trial. Future research will be directed at reducing the risks of this treatment as well as understanding which patients would best benefit from the treatment.”

Dr Jan Dörr, from the NeuroCure Clinical Research Center, Charité-Universitätsmedizin, Berlin, Germany, made this comment about this clinical trial: “These results are impressive and seem to outbalance any other available treatment for multiple sclerosis. This trial is the first to show complete suppression of any inflammatory disease activity in every patient for a long period…However, aHSCT has a poor safety profile, especially with regards to treatment-related mortality.”

He added: “So, will this study change our approach to treatment of multiple sclerosis? Probably not in the short-term, mainly because the mortality rate will still be considered unacceptably high. Over the longer term (and) in view of the increasing popularity of using early aggressive treatment, there may be support for considering aHSCT less as a rescue therapy and more as a general treatment option, provided the different protocols are harmonized and optimized, the tolerability and safety profile can be further improved, and prognostic markers become available to identify patients at risk of poor prognosis in whom a potentially more hazardous treatment might be justified.”

CardioCell LLC Clincal Trial Tests Ischemia-Resistant Mesenchymal Stem Cells in Heart Failure


The cell therapy company CardioCell LLC has completed enrolling 23 patients for its Phase 2a chronic heart failure trial. These subjects were enrolled at Emory University in Atlanta, GA, MedStar Washington Hospital Center in Washington DC, and three other hospitals.

This study has the ponderous title of “Single-blind, Placebo-controlled, Crossover, Multicenter, Randomized Study to Assess the Safety, Tolerability and Preliminary Efficacy of Single Intravenous Dose of Ischemia-tolerant of Allogeneic Mesenchymal Bone Marrow Cells to Subjects With Heart Failure of Non-ischemic Etiology.”

This clinical trial will examine the safety of CardioCell’s proprietary ischemic-tolerant mesenchymal stem cells in heart failure patients. The trial will also test the ability of these cells to improve the heart function of these safe patients.

Ischemia-resistant mesenchymal stem cells have are extracted from bone marrow and then subjected to harsh cell culture conditions that toughen them up and improves their therapeutic capacities.

Cardiologist Javed Butler said that this clinical trial has been designed to use this novel intervention in a carefully selected group of patients who met rigorous inclusion and exclusion criteria.

This trial will deliver ischemia-tolerant mesenchymal stem cells (itMSCs) by means of intravenous infusion into heart failure patients and then monitor these patients to determine if the itMSC-treated patients show signs of improvement in heat function.

These itMSCs are licensed under the parent company Stemedica and these are allogeneic cells that were isolated from young, healthy donors and grown under hypoxic conditions. Once grown under these harsh culture conditions, the itMSCs increase their ability to home to damaged tissues and engraft into those tissues. itMSCs also secrete increased levels of growth and trophic factors that promote neurogenesis and tissue healing.

RENEW Trial Shows Stem Cell Mobilization Has Some Potential for Refractory Angina


The RENEW clinical trial has examined the ability of “CD34+” stem cells from bone marrow to alleviate the symptoms of refractory angina.

Angina pectoris is a crushing chest pain that afflicts people when the heart receives too little oxygen to support it for the workload placed upon it. Angina pectoris typically results from the blockage of coronary arteries as a result of atherosclerosis. Treatment of angina pectoris usually includes PCI or percutaneous coronary intervention, which involves the placement of a stent in the narrowed coronary artery, in combination with drug treatments like beta blockers, and/or cardiac nitrate (e.g., nitroglycerine).

Angina pectoris is also classified according to the severity of the disease. The Canadian Cardiovascular Society grading of angina pectoris (which is very similar to the New York Heart Association classification) uses four classes (I-IV) to classify the disease. Patients with Class I angina only experience pain during strenuous or prolonged physical activity. Those with Class II angina have a slight limitation in physical activity and experience pain during vigorous physical activity (climbing several flights of stairs). Class III angina manifests as pain during everyday living activities, such as climbing one flight of stairs. These patients experience moderate limitation of their physical activity. Those with Class IV angina experience pain at rest and are unable to perform any activity without angina, and therefore, suffer from severe limitations on their activity.

Refractory angina pectoris (also known as chronic symptomatic coronary artery disease) stubbornly resists medical therapy and is unamenable to conventional revascularization procedures. Patients with refractory angina pectoris have reproducible lifestyle-limiting symptoms of chest pain, shortness of breath, and easy fatigability.

The results of the RENEW clinical trial were presented at the Society for Cardiovascular Angiography and Interventions 2016 sessions. Even though the trial was prematurely ended for financial reasons, the results that were collected suggest that cell-based therapies might provide relief for suffers of refractory angina pectoris.

RENEW tested the effectiveness of the intravenous infusion of the protein called granulocyte-colony simulating factor (G-CSF), which mobilizes CD34+ stem cells from the bone marrow. Once summoned from the bone marrow, CD34+ stem cells can help establish new blood vessels and increase blood flow throughout the heart. CD34+ stem cells also seem to have some ability to home to sites of damage. Therefore, G-CSF infusions might provide some relief to patients with refractory angina pectoris.

Dr. Timothy D. Henry of the Cedars-Sinai Heart Institute in Los Angles, CA, said: “Clinicians are seeing more RA (refractory angina) patients because people are living longer. Unfortunately, despite better medical care, these people are still confronting ongoing symptoms that affect their daily lives.”

Patients enrolled in the RENEW trial had either class III or IV angina and experiences ~7 chest pain episodes each week. These patients were also not candidates for revascularization (PCI) and their treadmill exercise times were between 3-10 minutes.

112 RA patients were randomly broken into three groups. Group 1 received standard care (28), group 2 received placebo injections (27), and group 3 received treatment with CD34+ cells. The trial was double-blinded and placebo controlled. The original aim was to test 444 RA patients, but financial concerns truncated the study at 112 patients.

All patients were assessed at three, six, 12, and 24 months after treatment by means of exercise tolerance, anginal attacks, and major adverse cardiovascular events (MACEs).

The cell-treated patients increased their exercise times by more than two minutes at three (average 122-second increase), six (average 142-second increase), and twelve (average 124-second increase) months. This is significant, since the other two groups showed no significant increase in their exercise times.

Patients in the cell-treated group also experienced 40 percent fewer anginal attacks at six months relative to the placebo-treated group.

At two years after the treatment, the CD34+-treated group have lower mortality rates (3.7 percent) compared to those who received standard care (7.1 percent) and those who received the placebo (10 percent).

Finally, after two years, the cell-treated group had lower MACE rates (46 percent) than the standard care group (68 percent). The MACE rate for the placebo-treated group was 43 percent.

On the strength of these results, Dr. Henry said, “Cell therapy appears to be a promising approach for these patients who have few options. Our results were consistent with phase 2 results from the ACT34 trial (author’s note: which gave patients infusions of cells and not G-CSF).”

Tom Povsic of the Duke Clinical Research Institute said of the RENEW trial, “It is unfortunate the early termination of this study precludes a full evaluation of the efficacy of this therapy for these patients with very few options.  Studies like RENEW are critical to developing reliable and effective therapies for heart patients, and continued cellular therapies for heart patients, and continued funding is essential to advancing the work that this study began.  We need to find a way to bring these therapies as quickly as safely as possible.”

Dr. Povsic’s words certainly ring true.  Even though the results of the RENEW study are essentially positive, RENEW was planed to be almost three times the size of Douglas Losordo’s earlier, successful ACT34 study.  The results of both the ACT34 and RENEW studies are largely positive.  Perhaps more importantly, both studies have also established that cell-based treatments for RA patients are safe.  However, given the voracity of the FDA for clinical data before it will approve a treatment, even for patients with few current options, it is unlikely that these studies will prove large enough to satisfy the agency.  Until a very large study shows cell-based treatments to be not only safe but efficacious, only then will the mighty turtle known as the FDA approve such treatments for RA patients.

First Patient Randomized for ACTIsSIMA Trial for Chronic Stroke


SanBio, a regenerative medicine company in Mountain View, California, has announced the randomization of the first enrolled patient in the ACTIsSIMA Phase 2B clinical trial. This trial will examine the efficacy of SanBio’s proprietary SB623 product in patients who suffer from chronic motor deficits as a result of strokes. SB623 consists of modified adult bone-marrow-derived stem cells. A secondary purpose of this trial is to evaluate the safety of SB623 in these patients.

Ischemic strokes account for about 87 percent of all strokes in the United States. Ischemic strokes occur when there is an obstruction in one or more of the blood vessels that provide blood and oxygen to the brain. On the order of 800,000 cases of ischemic stroke occur in the United States every year, and it is the leading cause of acquired disability in the United States. Present drug treatments for stroke either try to prevent strokes or address patients who have recently suffered a stroke. Unfortunately, there are no medical treatments currently available for people who live with the effects of stroke, months or even years after suffering a stroke.

SB623 cells are derived from bone marrow mesenchymal stem cells extracted from healthy donors. These cells are designed to promote recovery from injury by triggering the brain’s natural regenerative ability. SB623 cells have been genetically engineered to express a modified version of the Notch gene (NICD) that conveys upon the cells the ability to promote the formation of new blood vessels and the survival of endothelial cells that form these new blood vessels (see J Transl Med. 2013, 11:81. doi: 10.1186/1479-5876-11-81).

SB623 was tested in a Phase 1/2A clinical trial in which SB623 was implanted into stroke patients and produced some improved motor function.

This follow-up trial, ACTIsSIMA, will treat stroke patients with SB623 cells in order to examine the safety and efficacy of SB623 cells. All patients in this trial have suffered from a stroke anywhere from six months to five years. Also, all patients must exhibit chronic motor impairments.

Damien Bates, M.D., Chief Medical Officer & Head of Research at SanBio, said, “Our previous trial suggested there was potential for SB623 to improve outcomes for patients with lasting motor deficits following an ischemic stroke. Randomization of the first subject marks an exciting step toward further evaluating this treatment as a promising new option for patients.”

For this trial, SanBio is collaborating with Sunovion Pharmaceuticals, Inc. Sunovion is a wholly owned subsidiary of Sumitomo Dainippon Pharma Co., Ltd., and SanBio and Sumitomo Dainippon Pharma have entered into a joint development and license agreement for exclusive marketing rights in North America for SB623 for chronic stroke.

The ACTIsSIMA trial will include approximately 60 clinical trial sites throughout the United States, and total enrollment is expected to reach 156 patients.

G-CSF Fails to Improve Long-Term Clinical Outcomes in REVIVAL-2 Trial


Granulocyte-Colony Stimulating Factor (G-CSF) is a glycoprotein (protein with sugars attached to it) that signals to the bone marrow to produce granulated white blood cells (specifically neutrophils), and to release stem cells and progenitor cells into the peripheral circulation.

This function of G-CSF makes it a candidate treatment for patients who have recently experienced a heart attack, since the release of stem cells from the bone marrow could, in theory, bring more stem cells to the damaged heart to heal it. Additionally, G-CSF is known to induce the proliferation and enhance the survival of heart muscle cells.

In several experiments with laboratory animals showed that G-CSF treatments after a heart attack significantly reduced mortality (Moazzami K, Roohi A, and Moazzimi B. Cochrane Database Systematic Reviews 2013; 5: CD008844. However, in a clinical trial known as the REVIVAL-2 trial, a double-blind, placebo-controlled study, G-CSG treatment failed to influence the performance of the heart six months after administration.

Now Birgit Steppich and others have published a seven-year follow-up of the subjects in the original REVIVAL-2 study to determine if G-CSF had long-term benefits that were not revealed in the short-term study. These results were published in the journal Thrombosis and Haemostasis (115.4/2016).

Of the initially enrolled 114 patients, 106 patients completed the seven-year follow-up. The results of this trial showed that G-CSF treatment for five days in successfully revascularized heart attack patients did not alter the incidence of death, recurrent heart attacks, stroke, or secondary adverse heart events during the seven-year follow-up.

These results are similar to those of the STEMMI trial, which treated patients with G-CSF for six days 10-65 hours after the reperfusion. In a five-year follow-up of 74 patients, there were no differences in the occurrence of major cardiovascular events between the G-CSF-treated group and the placebo group (Achili F, et al., Heart 2014; 100: 574-581).

Therefore, it appears that even though G-CSF worked in laboratory rodents that had suffered heart attacks, this treatment does not consistently benefit human heart attack patients. Although why it does not work will almost certainly require more insights than we presently possess.

Hematopoietic Stem Cells Use a Simple Heirarchy


New papers in Science magazine and the journal Cell have addressed a long-standing question of how the descendants of hematopoietic stem cells in bone marrow make the various types of blood cells that course through our blood vessels and occupy our lymph nodes and lymphatic vessels.

Hematopoietic stem cells (HSCs) are partly dormant cells that self-renew and produce so-called “multipotent progenitors” or MPPs that have reduced ability to self-renew, but can differentiate into different blood cell lineages.

The classical model of how they do this goes like this: the MPPs lose their multipotency in a step-wise fashion, producing first, common myeloid progenitors (CMPs) that can form all the red and white blood cells except lymphocytes, or common lymphoid progenitors (CLPs) that can form lymphocytes (see the figure below as a reference). Once these MPPs form CMPs, for example, the CMP then forms either an MEP that can form either platelets or red blood cells, or a GMP. which can form either granulocytes or macrophages. The possibilities of the types of cells the CMP can form in whittled down in a step-by-step manner, until there is only one choice left. With each differentiation step, the cell loses its capacity to divide, until it becomes terminally differentiated and becomes platelet-forming megakarocyte, red blood cell, neutrophil, macrophage, dendritic cells, and so on.

hematopoiesis-from-multipotent-stem-cell

These papers challenge this model by arguing that the CMP does not exist. Let me say that again – the CMP, a cell that has been identified several times in mouse and human bone marrow isolates, does not exist. When CMPs were identified from mouse and human none marrow extracts, they were isolated by means of flow cytometry, which is a very powerful technique, but relies on the assumption that the cell type you want to isolate is represented by the cell surface protein you have chosen to use for its isolation. Once the presumptive CMP was isolated, it could recapitulate the myeloid lineage when implanted into the bone marrow of laboratory animals and it could also produce all the myeloid cells in cell culture. Sounds convincing doesn’t it?

In a paper in Science magazine, Faiyaz Notta and colleagues from the University of Toronto beg to differ. By using a battery of antibodies to particular cell surface molecules, Notta and others identified 11 different cell types from umbilical cord blood, bone marrow, and human fetal liver that isolates that would have traditionally been called the CMP. It turns out that the original CMP isolate was a highly heterogeneous mixture of different cell types that were all descended from the HSC, but had different developmental potencies.

Notta and others used single-cell culture assays to determine what kinds of cells these different cell types would make. Almost 3000 single-cell cultures later, it was clear that the majority of the cultured cells were unipotent (could differentiate into only one cell type) rather than multipotent. In fact, the cell that makes platelets, the megakarocyte, seems to derive directly from the MPP, which jives with the identification of megakarocyte progenitors within the HSC compartment of bone marrow that make platelets “speedy quick” in response to stress (see R. Yamamoto et al., Cell 154, 1112 (2013); S. Haas, Cell Stem Cell 17, 422 (2015)).

Another paper in the journal Cell by Paul and others from the Weizmann Institute of Science, Rehovot, Israel examined over 2700 mouse CMPs and subjected these cells to gene expression analyses (so-called single-cell transriptome analysis). If the CMP is truly multipotent, then you would expect it to express genes associated with lots of different lineages, but that is not what Paul and others found. Instead, their examination of 3461 genes revealed 19 different progenitor subpopulations, and each of these was primed toward one of the seven myeloid cell fates. Once again, the presumptive CMPs looked very unipotent at the level of gene expression.

One particular subpopulation of cells had all the trappings of becoming a red blood cell and there was no indication that these cells expressed any of the megakarocyte-specific genes you would expect to find if MEPS truly existed. Once again, it looks as though unipotency is the main rule once the MPP commits to a particular cell lineage.

Thus, it looks as though either the CMP is a very short-lived state or that it does not exist in mouse and human bone marrow. Paul and others did show that cells that could differentiate into more than one cell type can appear when regulation is perturbed, which suggests that under pathological conditions, this system has a degree of plasticity that allows the body to compensate for losses of particular cell lineages.

A model of the changes in human My-Er-Mk differentiation that occur across developmental time points. Graphical depiction of My-Er-Mk cell differentiation that encompasses the predominant lineage potential of progenitor subsets; the standard model is shown for comparison. The redefined model proposes a developmental shift in the progenitor cell architecture from the fetus, where many stem and progenitor cell types are multipotent, to the adult, where the stem cell compartment is multipotent but the progenitors are unipotent. The grayed planes represent theoretical tiers of differentiation.
A model of the changes in human My-Er-Mk differentiation that occur across developmental time points.
Graphical depiction of My-Er-Mk cell differentiation that encompasses the predominant lineage potential of progenitor subsets; the standard model is shown for comparison. The redefined model proposes a developmental shift in the progenitor cell architecture from the fetus, where many stem and progenitor cell types are multipotent, to the adult, where the stem cell compartment is multipotent but the progenitors are unipotent. The grayed planes represent theoretical tiers of differentiation.

Fetal HSCs, however, are a bird of a different feather, since they divide quickly and reside in fetal liver.  Also, these HSCs seem to produce CMPs, which is more in line with the classical model.  Does the environmental difference or fetal liver and bone marrow make the difference?  In adult bone marrow, some HSCs nestle next to blood vessels where they encounter cells that hang around blood vessels known as “pericytes.”  These pericytes sport a host of cell surface molecules that affect the proliferative status of HSCs (e.g., nestin, NG2).  What about fetal liver?  That’s not so clear – until now.

In the same issue of Science magazine, Khan and others from the Albert Einstein College of Medicine in the Bronx, New York, report that fetal liver also has pericytes that express the same cell surface molecules as the ones in bone marrow, and the removal of these cells reduces the numbers of and proliferative status of fetal liver HSCs.

Now we have a conundrum, because the same cells in bone marrow do not drive HSC proliferation, but instead drive HSC quiescence.  What gives? Khan and others showed that the fetal liver pericytes are part of an expanding and constantly remodeling blood system in the liver and this growing, dynamic environment fosters a proliferative behavior in the fetal HSCs.

When umbilical inlet is closed at birth, the liver pericytes stop expressing Nestin and NG2, which drives the HSCs from the fetal liver to the other place were such molecules are found in abundance – the bone marrow.

These models give us a better view of the inner workings of HSC differentiation.  Since HSC transplantation is one of the mainstays of leukemia and lymphoma treatment, understanding HSC biology more perfectly will certainly yield clinical pay dirt in the future.

 

BrainStorm Cell Therapeutics Will Conduct Phase 2 Clinical Trial on ALS Patients with Their NurOwn® Cells


The biotechnology company BrainStorm Cell Therapeutics Inc. has developed an autologous stem cell therapy for several neurodegenerative diseases including Amyotrophic Lateral Sclerosis (ALS, also known as Lou Gehrig’s disease), Multiple Sclerosis (MS) and Parkinson’s Disease (PD). BrainStorm has designed a proprietary product called NurOwn™ that is made from the patient’s own bone marrow mesenchymal stem cells (BM-MSCs). Essentially, the patient’s BM-MSCs are isolated, purified, and cultured in a specialized culture system that drives the BM-MSCs to differentiate into nerve-like cells that Neurotrophic Factors (NTF). These NTFs have the capacity to keep nerve cells alive and prevent moribund cells from dying.

Figure taken from http://www.brainstorm-cell.com/index.php/science-technology/nurown%E2%84%A2
Figure taken from http://www.brainstorm-cell.com/index.php/science-technology/nurown%E2%84%A2. 

By transplanting NurOwn cells back into the patient at or near the site of neural damage, in the spine and/or muscles, it could potentially delay or even roll back damage from neurodegeneration. NurOwn cells have proven their efficacy in animal experiments (e.g., STEM CELLS 2008;26:2542–2551), and in a few small clinical trials.

In one case, a 75-year-old man who suffered from ALS and myasthenia gravis (the immune system attacks your own receptors for acetylcholine at the neuromuscular junction, which prevents the muscle contraction), was treated with NurOwn cells, and experienced the following improvement 1 month later.

Figure copying (a test of visuospatial function) of the patient, before and 1 month after the first enhanced (neurotrophic factors producing) mesenchymal stem cell (MSC‐NTF) transplantation.
Figure copying (a test of visuospatial function) of the patient, before and 1 month after the first enhanced (neurotrophic factors producing) mesenchymal stem cell (MSC‐NTF) transplantation.

This is only a case study and involves only one patient, which is the absolute lowest-quality evidence you can have in medicine.  Therefore, this study is suggestive that NurOwn cells can help ALS patients improve.

Now BrainStorm Cell Therapeutics has entered into a collaborative agreement with Hadassah Medical Center in Jerusalem, Israel, to conduct a Phase 2 clinical trial to test the ability of NurOwn cells to treatment patients with Amyotrophic Lateral Sclerosis (ALS).

This clinical trial is not BrainStorm’s first rodeo, since they have conducted two other clinical trials in collaboration with Hadassah Medical Center. BrainStorm hopes that the results of this clinical trial will provide guidance in preparing a Phase 3 clinical trial that will test their NurOwn® stem cell based therapy in patients suffering from ALS.

In this trial, BrainStorm plans to enroll up to 24 ALS patients, all of whom will receive three consecutive stem cell transplantations of their own BM-MSCs that have been genetically engineered to secrete NFTs. The goal of this trial is to establish the safety and efficacy of a treatment regimen that includes multiple doses of stem cells. Because this trial includes human subjects, it must be approved by Hadassah’s Helsinki Committee and the Israeli Ministry of Health before the study can commence.

Professor Dimitrios Karussis, MD, PhD, Head of the Unit of Neuroimmunology and Cell Therapies at Hadassah’s Department of Neurology, who served as Principal Investigator in Brainstorm’s prior ALS studies, will serve as the Principal Investigator for this trial.

“NurOwn has generated promising clinical data in ALS and has the potential to offer a new approach for the treatment of patients afflicted with this disease,” stated Professor Karussis. “We are excited to be collaborating with BrainStorm to advance this product to the next phase of development and the application of stem cell therapies in similar neurological diseases in general.”

“Evaluating multiple doses with NurOwn is an important next step in our efforts to understand the treatment effect of this investigative medicine,” stated Chaim Lebovits, CEO of Brainstorm. “We are pleased to continue our partnership with Hadassah Medical Center, which has long maintained a reputation for excellence in the treatment of neurological disorders.”

Fat-Based Stem Cell Product HemaXellerate Will be Tested in Clinical Trials for Aplastic Anemia


A regenerative medicine company called Regen BioPharma, Inc., has announced that it received a communication from the U.S. Food and Drug Administration that grants it permission to initiate clinical trials under its Investigational New Drug (IND) #15376.

Granting of the IND gives the green light to Regen BioPharma to begin testing their product HemaXellerate in clinical trials with human patients. HemaXellerate is a personalized stem cell treatment for patients whose bone marrow no longer works (aplastic anemia). It uses fat-based stem cells from a patient’s own belly fat to treat bone marrow that has been damaged. HemaXellerate uses the patient’s own fat-based stem cells as a source of endothelial (blood vessel) cells to heal damaged bone marrow.

Aplastic anemia occurs when the bone marrow stops producing sufficient numbers of blood cells. It is a potentially fatal disease of the bone marrow that leads to bleeding, infection and fever. Patients with severe or even very severe aplastic anemia have a mortality rate of greater than 70%. Current treatments for aplastic anemia include blood transfusions, immunosuppression and stem cell transplantation.

This Phase I clinical trial will treat patients who have been diagnosed with refractory aplastic anemia, which includes those patients with aplastic anemia who were unsuccessfully treated with first-line immunosuppressive therapy. Patients treated with HemaXellerate with be followed for safety parameters and signals of treatment efficacy. Since this will be an unblinded trial, all data will be available as the study progresses.

“Current drug-based approaches for healing bone marrow dysfunction involve flooding the body with growth factors, which is extremely expensive and causes unintended consequences because of lack of selectivity,” said Harry Lander, Ph.D., President and Chief Scientific Officer of Regen Biopharma. “By utilizing a cell-based approach that both modulates the immune system and stimulates production of blood cells, we aim to offer alternatives to the current approaches to treating patients with aplastic anemia. This product will complement our immune-modulatory pipeline that includes a potential novel checkpoint inhibitor.”

If HemaXellerate passes this clinical trial, Regen Biopharma would like to position HemaXellerate as a treatment for bone marrow dysfunction on par with other members of the hematopoietic growth factor market that includes drugs such as Neupogen®, Neulasta®, Leukine® and Revolade®.

“The FDA clearance marks a substantial step for Regen, in that we are now a clinical-stage company. We are grateful to our collaborators and scientific advisory board members who have worked tirelessly in bringing our product to the point where the FDA has permitted treatment of patients,” said David Koos, Ph.D., Chairman and Chief Executive Officer of Regen BioPharma. “We believe the success of today will not only allow for the rapid execution of HemaXellerate’s development plan, but will also allow for more rapid translation of the company’s other immune modulatory products to the clinic.”

ASTIC Clinical Trial Fails to Show Clear Advantage to Hematopoietic Stem Cell Transplantation as a Treatment for Crohn’s Disease


Patients with Crohn’s disease (CD) sometimes suffer from daily bouts of stomach pain and diarrhea. These constant gastrointestinal episodes can prevent them from absorbing enough nutrition to meet their needs, and, consequently, they can suffer from weakness, fatigue, and a general failure to flourish.

To treat Crohn’s disease, physicians use several different types of drugs. First there are the anti-inflammatory drugs, which include oral 5-aminosalicylates such as sulfasalazine (Azulfidine), which contains sulfur, and mesalamine (Asacol, Delzicol, Pentasa, Lialda, Apriso). These drugs, have several side effects, but on the whole are rather well tolerated. If these don’t work, then corticosteroids such as prednisone are used. These have a large number of side effects, including a puffy face, excessive facial hair, night sweats, insomnia and hyperactivity. More-serious side effects include high blood pressure, diabetes, osteoporosis, bone fractures, cataracts, glaucoma and increased chance of infection.

If these don’t work, then the stronger immune system suppressors are brought out. These drugs have some very serious side effects. Azathioprine (Imuran) and mercaptopurine (Purinethol) are two of the most widely used of this group. If used long-term, these drugs can make the patient more susceptible to certain infections and cancers including lymphoma and skin cancer. They may also cause nausea and vomiting. Infliximab (Remicade), adalimumab (Humira) and certolizumab pegol (Cimzia) are the next line of immune system suppressors. These drugs are TNF inhibitors that neutralize an immune system protein known as tumor necrosis factor (TNF). These drugs are also associated with certain cancers, including lymphoma and skin cancers. The next line of drugs include Methotrexate (Rheumatrex), which is usually used to treat cancer, psoriasis and rheumatoid arthritis, but methotrexate also quells the symptoms of Crohn’s disease in patients who don’t respond well to other medications. Short-term side effects include nausea, fatigue and diarrhea, and rarely, it can cause potentially life-threatening pneumonia. Long-term use can lead to bone marrow suppression, scarring of the liver and sometimes to cancer. You will need to be followed closely for side effects.

Then there are specialty medicines for patients who do not respond to other medicines or who suffer from openings in their lower large intestines to the outside world (fistulae). These include cyclosporine (Gengraf, Neoral, Sandimmune) and tacrolimus (Astagraf XL, Hecoria). These have the potential for serious side effects, such as kidney and liver damage, seizures, and fatal infections. These medications are definitely cannot be used for long period of time as their side effects are too dangerous.

If the patient still does not experience any relief, then two humanized mouse monoclonal antibodies natalizumab (Tysabri) and vedolizumab (Entyvio). Both of these drugs bind to and inhibit particular cell adhesion molecules called integrins, and in doing so prevent particular immune cells from binding to the cells in the intestinal lining. Natalizumab is associated with a rare but serious risk of a brain disease that usually leads to death or severe disability called progressive multifocal leukoencephalopathy. In fact, so serious are the side effects of this medicine that patients who take this drug must be enrolled in a special restricted distribution program. The other drug, vedolizumab, works in the same way as natalizumab but does not seem to cause this brain disease. Finally, a drug called Ustekinumab (Stelara) is usually used to treat psoriasis. Studies have shown it’s useful in treating Crohn’s disease and might useful when other medical treatments fail. Ustekinumab can increase the risk of contracting tuberculosis and an increased risk of certain types of cancer. Also there is a risk of posterior reversible encephalopathy syndrome. More common side effects include upper respiratory infection, headache, and tiredness.

If this litany of side effects sounds undesirable, then maybe a cell-based treatment can help Crohn’s patients. To that end, a clinical trial called the Autologous Stem Cell Transplantation International Crohn’s Disease or ASTIC trial was conducted and its results were published in the December 15th, 2015 edition of the Journal of the American Medical Association.

The ASTIC trial enrolled 45 Crohn’s disease patients, all of whom underwent stem cell mobilization with cyclophosphamide and filgrastim, and were then randomly assigned to immediate stem cell transplantation (at 1 month) or delayed transplantation (at 13 months; control group).  Blood samples were drawn and mobilized stem cells were isolated from the blood.  In twenty-three of these patients, their bone marrow was partially wiped out and reconstituted by means of transplantations with their own bone marrow stem cells. The other 22 patients were given standard Crohn disease treatment (corticosteroids and so on) as needed.

The bad news is that hematopoietic stem cell transplantations (HSCT) were not significantly better than conventional therapy at inducing sustained disease remission, if we define remission as the patient not needing any medical therapies (i.e. drugs) for at least 3 months and no clear evidence of active disease on endoscopy and GI imaging at one year after the start of the trial. All patients in this study had moderately to severely active Crohn’s disease that was resistant to treatment, had failed at least 3 immunosuppressive drugs, and whose disease that was not amenable to surgery.  All participants in this study had impaired function and quality of life.  Also, the stem cell transplantation procedure, because it involved partially wiping out the bone marrow, cause considerable toxicities.

Two patients who underwent HSCT (8.7%) experienced sustained disease remission compared to one control patient (4.5%). Fourteen patients undergoing HSCT (61%) compared to five control patients (23%) had discontinued immunosuppressive or biologic agents or corticosteroids for at least 3 months. Eight patients (34.8%) who had HSCTs compared to two (9.1%) patients treated with standard care regimens were free of the signs of active disease on endoscopy and radiology at final assessment.

However, there were 76 serious adverse events in patients undergoing HSCT compared to 38 in controls, and one patient undergoing HSCT died.

So increased toxicities and not really a clear benefit to it; those are the downsides of the ASCTIC study.  An earlier report of the ASTIC trial in 2013, while data was still being collected and analyzed was much more sanguine.  Christopher Hawkey, MD, from the University of Nottingham in the United Kingdom said this: “Some of the case reports are so dramatic that it’s reasonable to talk about this being a cure in those patients.”  These words came from a presentation given by Dr. Hawkey at Digestive Disease Week 2013.  Further analysis, however, apparently, failed to show a clear benefit to HSCT for the patients in this study.  It is entirely possible that some patients in this study did experience significant healing, but statistically, there was no clear difference between HSCT and conventional treatment for the patients in this study.

The silver lining in this study, however, is that compared to the control group, significantly more HSCT patients were able to stop taking all their immunosuppressive therapies for the three months prior to the primary endpoint. That is a potential upside to this study, but it is unlikely for most patients that this upside is worth the heightened risk of severe side effects. An additional potential upside to this trial is that patients who underwent HSCT showed greater absolute reduction of clinical and endoscopic disease activity. Again, it is doubtful if these potential benefits are worth the higher risks for most patients although it might be worth it for some patients.

Therefore, when HSCT was compared with conventional therapy, there was no statistically significant improvement in sustained disease remission at 1 year. Furthermore, HSCT was associated with significant toxicity. Overall, despite some potential upside to HSCT observed in this study, the authors, I think rightly, conclude that their data do not support the widespread use of HSCT for patients with refractory Crohn’s disease.

Could HSCT help some Crohn’s patients more than others? That is a very good question that will need far more work with defined patient populations to answer.  Perhaps further work will ferret out the benefits HSCT has for some Crohn’s disease patients relative to others.

The ASTIC trial was a collaborative project between the European Society for Blood and Marrow Transplantation (EBMT) and the European Crohn’s and Colitis Organization (ECCO) and was funded by the Broad Medical Foundation and the Nottingham Digestive Diseases Centers.

A Common Osteoporosis Drug Protects Bone Marrow Stem Cells from DNA Damage


A commonly used treatment for osteoporosis can protect stem cells in bone from the ravages of aging, according to a new study from the University of Sheffield.

Ilaria Bellantuono and her colleagues have discovered that zoledronate can extend the lifespan of bone marrow mesenchymal stem cells by reducing the degree of DNA damage experienced by these stem cells.

As stem cells age, they accumulate DNA damage, and this seems to be one of the most important mechanisms of aging. DNA damage can cause stem cells to lose their capacity to maintain tissues and repair them when those tissues are damaged. This new research from Bellantuono’s laboratory shows that zoledronate can protect mesenchymal stem cells from DNA damage, which enhances their survival and maintains their function.

According the Professor Bellantuono, “The drug enhances the repair of the damage in DNA occurring with age in stem cells in the bone. It is also likely to work in other stem cells too.”

She continued: “This drug has been shown to delay mortality in patients affected by osteoporosis but until now we didn’t know why. These findings provide an explanation as to why it may help people to live longer.

“Now we want to understand whether the drug can be used to delay or revert the aging in stem cells in older people and improve the maintenance of tissues such as the heart, the muscle and immune cells, keeping them healthier for longer.

“We want to understand whether it improves the ability of stem cells to repair those tissues after injury, such as when older patients with cancer undergo radiotherapy.”

Almost half of elderly patients over 75 years of age have three or more diseases at the same time, such as osteoporosis, diabetes, cardiovascular disease, infections, and muscle weakness. However, work like this suggests that drugs like zoledronate could be used to treat, prevent or perhaps even delay the onset of such diseases.

Dr Bellantuono added: “We are hopeful that this research will pave the way for a better cure for cancer patients and keeping older people healthier for longer by reducing the risk of developing multiple age-related diseases.”

Scientists Grow New Diaphragm Tissue In Laboratory Animals


The diaphragm is a parachute-shaped muscle that separates the thoracic cavity from the abdominopelvic cavity and facilitates breathing. Contraction of the diaphragm increases the volume of the lungs, thus dropping the pressure in the lungs below the pressure of the surrounding air and causing air to rush into the lungs (inhalation). Relaxation of the diaphragm decreases the volume of the lungs and increases the pressure in the lungs so that it exceeds the pressure of the air, and air leaves the lungs (exhalation). The diaphragm is also important for swallowing. One in 2,500 babies are born with malformations or perforations in their diaphragms, and this condition is usually fatal.

The usual treatment for this condition involves the construction of an artificial patch that properly covers the lesion, but has no ability to grow with the infant and is not composed of contractile tissue. Therefore, it does not assist in contraction of the diaphragm to assist in breathing.

A new study might change the prospects for these newborn babies. Tissue engineering teams from laboratories in Sweden, Russia and the United States have successfully grown new diaphragm tissue in rats by applying a mixture of stem cells embedded in a 3D scaffold made from donated diaphragm tissue. Transplantation of this stem cell/diaphragm matrix concoction into rats allowed the animals to regrow new diaphragm tissue that possessed the same biological characteristics as diaphragm muscle.
The techniques designed by this study might provide the means for repairing defective diaphragms or even hearts.

Doris Taylor, who serves as the director of regenerative medicine research at the Texas Heart Institute and participated in this revolutionary study, said: “So far, attempts to grow and transplant such new tissues have been conducted in the relatively simple organs of the bladder, windpipe and esophagus. The diaphragm, with its need for constant muscle contraction and relaxation puts complex demands on any 3D scaffold. Until now, no one knew whether it would be possible to engineer.”

Paolo Macchiarini, the director of the Advanced Center for Regenerative Medicine and senior scientist at Karolinska Institutet, who also participated in this study, said: “This bioengineered muscle tissue is a truly exciting step in our journey towards regenerating whole and complex organs. You can see the muscle contracting and doing its job as well as any naturally grown tissue.”

To make their tissue engineered diaphragms, the team used diaphragm tissue that had been taken from donor rats. They stripped these diaphragms of all their cells, but maintained all the connective tissue. This removed anything in these diaphragms that might cause the immune systems of recipient animals to reject the implanted tissue, while at the same time keeping all the things that give the diaphragm its shape and form. In the laboratory, the decellularized diaphragms had lost all their elasticity. However, once these diaphragm matrices were seeded with bone marrow-derived stem cells and transplanted into recipient laboratory animals, the diaphragm scaffolds began to function as well as normal, undamaged diaphragms.

If this new technique can be successfully adapted to human patients, it could replace the damaged diaphragm tissue of the patient with tissue that would constantly contract and grow with the child. Additionally, the diaphragm could be repaired by utilizing a child’s own stem cells. As a bonus, this technique might also provide a new way to

Next, the team must test this technique on larger animals before it can be tested in a human clinical trial.

The study was published in the journal Biomaterials.

How Stem Cell Therapy Protects Bone In Lupus


Systemic Lupus Erythematosis, otherwise known as lupus, is an autoimmune disease cause your own immune system attacking various cells and tissues in your body. Lupus patients can suffer from fatigue, joint pain and selling and show a marked increased risk or osteoporosis.

Clinical trials have established that infusions of mesenchymal stem cells (MSCs) can significantly improve the condition of lupus patients, but exactly why these cells help these patients is not completely clear. Certainly suppression of inflammation is probably part of the mechanism by which these cells help lupus patients, but how do these cells improve the bone health of lupus patients?

Songtao Shi and his team at the University of Pennsylvania have used an animal model of lupus to investigate this very question. In their hands, transplanted MSCs improve the function of bone marrow stem cells by providing a source of the FAS protein. FAS stimulates bone marrow stem cell function by means of a multi-step, epigenetic mechanism.

This work by Shi and his colleagues has implications for other cell-based treatment strategies for not only lupus, but other diseases as well.

“When we used transplanted stem cells for these diseases, we didn’t know exactly what they were doing, but saw that they were effective,” said Shi. “Now we’ve seen in a model of lupus that bone-forming mesenchymal stem cell function was rescued by a mechanism that was totally unexpected.”

In earlier work, Shi and his group showed that mesenchymal stem cell infusions can be used to treat various autoimmune diseases in particular animals models. While these were certainly highly desirable results, no one could fully understand why these cells worked as well as they did. Shi began to suspect that some sort of epigenetic mechanism was at work since the infused MSCs seemed to permanently recalibrate the gene expression patterns in cells.

In order to test this possibility, Shi and others found that lupus mice had a malfunctioning FAS protein that prevented their bone marrow MSCs from releasing pro-bone molecules that are integral for bone maintenance and deposition.

A deficiency for the FAS protein prevents bone marrow stem cells from releasing a microRNA called miR-29b.  The failure to release miR-29b causes its concentrations to increase inside the cells.  miR-29b can down-regulate an enzyme called DNA methyltransferase 1 (Dnmt1), and the buildup of miR-29b inhibits Dnmt1, which causes decreased methylation of the Notch1 promoter and activation of Notch signaling.  Methylation of the promoters of genes tends to shut down gene expression, and the lack of methylation of the Notch promoter increases Notch gene expression, activating Notch signaling.  Unfortunately, increased Notch signaling impaired the differentiation of bone marrow stem cells into bone-making cells.  Transplantation of MSCs brings FAS protein to the bone marrow stem cells by means of exosomes secreted by the MSCs.  The FAS protein in the MSC-provided exosomes reduce intracellular levels of miR-29b, which leads to higher levels of Dnmt1.  Dnmt1 methylates the Notch1 promoter, thus shutting down the expression of the Notch gene, and restoring bone-specific differentiation.

Shi and others are presently investigating if this FAS-dependent process is also at work in other autoimmune diseases.  If so, then stem cell treatments might convey similar bone-specific benefits.

Faster Bone Regeneration With a Little Wnt


Nick Evans and his colleagues at the University of Southampton, UK have discovered that transient stimulation of the Wnt signaling pathway in bone marrow stem cells expands them and enhances their bone-making ability. This finding has led to an intense search for drugs that can stimulate the Wnt pathway in order to stimulate bone formation in wounded patients.

The Wnt pathway is a highly conserved pathway found in sponges, starfish, sharks, and people. Wnt signaling controls pattern formation during development, and the growth of stem cells during healing.

When it comes to healing, bone fractures represent a sizeable societal problem, particularly among the aged. While most fractures heal on their own, approximately 10 percent of all fractures take over six months to heal or never heal at all. In the worse cases, fracture patients can require several surgeries or might need amputation in desperate cases.

According the Evans, he and his research group are screening a wide range of chemicals to determine if they stimulate Wnt signaling. If such chemicals prove safe to use in laboratory animals, then they might become clinical tools to help stimulate bone formation and healing in patients with recalcitrant fractures.

Research from Evans’ group has shown that transient stimulation of the Wnt signaling pathway in isolated bone marrow cells increases the number of bone-making progenitor cells. However, if the Wnt pathway is activated for too long a time period, this regenerative effect is lost or even reversed. Hence the need to develop treatments that deliver small molecules that stimulate Wnt signaling in bone marrow cells for a specified period of time and in a targeted fashion.

Evans and his group have used nanoparticles loaded with Wnt proteins to do exactly that. The feasibility of this technology and its effectiveness requires further work, but the promise is there and the idea is more than a little intriguing.