Minneapolis Heart Institute Foundation Tests Stem Cell Combination in Heart Attack Patients

The Minneapolis Heart Institute Foundation has announced a new clinical trial that will examine the ability of a stem cell combination to treat patients with ischemic heart failure.

In patients who have suffered from former heart attacks, clogged coronary blood vessels and heart muscle that hibernates can result in a heart that no longer works well enough to support the life of the patient. The lack of blood flow to vital parts of the heart and an increasing work load can result is so-called “Ischemic heart failure.” Such heart failure after a previous heart attack is one of the leading cause of death and morbidity in the world. According to the World Health Organization, ischemic heart disease affects more than 12% of the world’s population.

Stem cell therapy has been tested as a potential treatment for ischemic heart disease. Despite flashes of remarkable success, the overall efficacy of these treatments has been relatively modest. Most clinical trials have used the patient’s own bone marrow cells. In this case, the cell population is very mixed and it might not even be stem cell populations in the bone marrow that are eliciting recovery. Also, the quality of each patient’s bone marrow is probably quite varied, which makes standardizing such experiments remarkably difficult. Other clinical trials have used bone marrow derived mesenchymal cells [MSCs]. Several clinical trials with MSCs have seen some improvement in patients. MSCs seem to induce the formation of new blood vessels and also seem to induce endogenous stem cell populations in the heart to come to life and fix the heart. Other trials have used cardiac stem cells (CSCs) that were derived from biopsies of the heart. Even though fewer clinical trials have tested the efficacy of CSCs in human patients, the trials that have been conducted suggest that these cells can truly regenerate damaged heart tissue.

The Minneapolis Heart Institute Foundation® (MHIF) has announced a new clinical trial which will examine the combination of MSCs with CSCs to treatment patients with ischemic heart failure. This clinical trial, the CONCERT study, will be led by Principal Investigator Jay Traverse, MD. The CONCERT study will implant MSC’s and CSC’s in order to determine if the combination would be more successful than using either alone based on pre-clinical studies in swine demonstrating an enhanced synergistic effect of the combination.

CONCERT is sponsored by the National Institutes of Health and the Cardiovascular Cell Therapy Research Network (CCTRN), of which MHIF is a charter member. This will be a phase II clinical trial, which means that the focus of this leg of the study is to assess the relative safety of CSCs and MSCs, delivered either alone, or in combination, in comparison to placebo, and to measure the efficacy of the stem cell cocktail as well. To that end, researchers will measure and note any change or improvement in left ventricular (LV) function by cardiac MRI as well as changes in various clinical outcomes (survival, 6-minute walking, blood pressure, etc.), and quality of life.

This phase II study is a randomized, blinded, placebo-controlled study that will enroll 160 subjects at seven different CCTRN sites throughout the U.S. All recruited subjects will have ischemic cardiomyopathy and an ejection fraction 5%). This is significant, because some work in animals suggests that CSCs can make new heart muscle tissue that can shrink the heart scar. The first 16 patients were recently enrolled in a FDA-required safety run-in phase, but the remaining patients will be enrolled in the fall after a three-month safety analysis is performed. Incidentally, this is the first cardiac stem cell trial to perform MRIs on patients with defibrillators and pacemakers

“This combination of cells represents the most potent cell therapy product ever delivered to patients,” said Dr. Traverse. “Confirming that both types of stem cells together work better than either individual cell type could lead to improved patient outcomes and better quality of life for ischemic heart failure patients.”

Dosing Recent Heart Attack Patients with G-CSF Doesn’t Seem To Work

Granulocyte-Colony Stimulating Factor (G-CSF)is a small protein that stimulates the bone marrow to produce more of a particular class of white blood cells called granulocytes and release them into the bloodstream. A commercially available version of G-CSF called Filgrastim (Neupogen) is used to boost the immune system of cancer patients whose immune systems have taken a beating from chemotherapy.

Because several clinical trials have shown that implanting bone marrow mononuclear fractions into the hearts of heart attack patients can improve the heart health of some heart attack patients, clinicians have supposed that injecting heart attack patients with drugs like filgrastim, which moves many bone marrow-derived cells into the bloodstream might also provide some relief for heart attack patients.

Nice idea, but it does not seem to work. Two clinical trials, STEMMI and REVIVAL-2, have given G-CSF to heart attack patients at different times after their heart attacks. Unfortunately both studies have failed to show a difference from the placebo.

In the REVIVAL-2 study, 114 patients were enrolled, and 56 received 10 micrograms per kilogram body weight G-CSF for five days, and the remaining patients received a placebo treatment.  G-CSF and the placebo were administered to patients five days after the hearts were successfully reperfused by percutaneous coronary intervention (this is a fancy way of saying stenting).  This study was double-blinded, placebo-controlled and well designed.  Unfortunately, when patients were studied seven years after treatment, there were no statistically significant differences between the treatment and the placebo groups when it came to the number of deaths, heart attacks, and strokes.  Thus, the authors conclude that G-CSF administration did not improve clinical outcomes for patients who had a heart attack (see Birgit Steppich, et al, Atherosclerosis and Ischemic Disease 115.4, 2016).

A second clinical trial, the STEMMI trial, was a prospective trial in which G-CSF treatment was begun 10-65 hours after reperfusion.  Here again, there were no structural differences between the placebo group and the G-CSF-treated group six months after treatment and a five-year follow-up analysis of 74 patients revealed no differences in the occurrence of major cardiovascular incidents between the two treatment groups (R.S. Ripa, and others, Circulation 2006; 113: 1983-1992).

The STEM-AMI clinical trial also showed no differences in clinical outcomes after G-CSF treatment as compared to placebo in 60 patients after three years (F. Achilli, and others, Heart 2014, 100: 574-581).

Why does this technique fail?  It is possible that the white blood cells that are mobilized by G-CSF are low-quality and do not express particular genes.  A study in rats has shown that G-CSF infusion increases the number of progenitor cells in the bloodstream, but fails to increase the number of progenitor cells in the heart after a heart attack (D. Sato, and others, Experimental Clinical Cardiology, 2012; 17:83-88).  In order for cells to home to the infarcted heart, they must express particular proteins on their surfaces.  For example, the cell surface protein CXCR4 is known to play an integral role in progenitor cell homing, along with several other proteins (see Taghavi and George, American Journal of Translational Research 2013; 5:404-411; Shah and Shalia, Stem Cells International 2011;2011:536758; Zaruba and Franz, Expert Opinion in Biological Therapy 2010; 10:321-335).  Indeed, Stein and others have shown that progenitor cells mobilized with G-CSF in human patients lack CXCR4 and other cell adhesion proteins thought to play a role in homing to the infarcted heart (Thromb Haemost 2010;103:638-643).

Therefore, even though all of these studies have not uncovered a risk in G-CSF treatment, the consensus of the data seems to be there no clinical benefit is conferred by treating heart attack patients with G-CSF.

Enrollment Completed in Phase 2 ALLSTAR Cardiac Clinical Trial

Capricor Therapeutics Inc. has announced the completion of patient enrollment in their Phase 2 ALLSTAR clinical trial.  ALLSTAR stands for ALLogeneic Heart STem Cells to Achieve Myocardial Regeneration, and this trial will test Capricor’s CAP-1002 product in patients suffering from cardiac dysfunction following a heart attack.

CAP-1002 cells are cardiosphere derived cells (CDCs) that were isolated from donors.  This investigational therapy is an off-the-shelf “ready to use” cardiac cell therapy that comes from donor heart tissue.  CAP-1002 cells are made to be directly infused into a patient’s coronary artery during a catheterization procedure.

These CDCs were tested in the CADUCEUS clinical trial, in which they were shown to decrease scar size and increase viable heart tissue when implanted into the hearts of heart attack patients.  One-year follow-up examinations of these confirmed the earlier results.

ALLSTAR will study a population similar to the one in the CADUCEUS study (patients who had experienced a heart attack 30-90 days earlier), except that ALLSTAR will treat patients 91-365 days after suffering a heart attack.  The extension of the patient pool was to see if the indication window for CAD-1002 could be extended.

The Capricor CEO Linda Marbàn said, “With the last patient in ALLSTAR having been dosed on September 30, we expect to report top-line 12-month primary efficacy outcome results in the fourth quarter of 2017.”

ALLSTAR is being sponsored by Capricor and is led by Drs. Timothy Henry and Rajendra Makkar of the Cedars-Sinai Heart Institute.  The trial is being conducted at approximately 25-40 sites across the U.S.

The Phase I portion of the trial was funded in part by the National Institutes of Health and completed enrollment in December 2013, and the Phase II portion of the trial is supported in large part by the California Institute for Regenerative Medicine (CIRM).

Patient-Specific Heart Muscle Cells Before the Baby Is Born

Prenatal ultrasound scans can detect congenital heart defects (CHDs) before birth. Some 1% of all children born per year have some kind of CHD. Most of these children will require some kind of rather invasive, albeit life-saving surgery but an estimated 25% of these children will die before their first birthday. This underscores the need for netter therapies of children with CHDs.

To that end, Shaun Kunisaka from C.S. Mott Children’s Hospital in Ann Arbor, Michigan and his colleagues have used induced pluripotent stem cell (iPSC) technology to make patient-specific heart muscle cells in culture from the baby’s amniotic fluid cells. Because these cells can be generated in less than 16 weeks, and because the amniotic fluid can be harvested at about 20-weeks gestation, this procedure can potentially provide large quantities of heart muscle cells before the baby is born.

In this paper, which was published in Stem Cells Translational Medicine, Kunisaki and others collected 8-10 milliliter samples of amniotic fluid at 20 weeks gestation from two pregnant women who provided written consent for their amniocentesis procedures. The amniotic fluid cells from these small samples were expanded in culture, and between passages 3 and 5, cells were selected for mesenchymal stem cell properties. These amniotic fluid mesenchymal stem cells were then infected with genetically engineered non-integrating Sendai viruses that caused transient expression of the Oct4, Sox2, Klf4, and c-Myc genes in these cells. The transient expression of these four genes drove the cells to dedifferentiate into iPSCs that were then grown and then differentiated into heart muscle cells, using well-worked out protocols that have become rather standard in the field.

Not only were the amniotic fluid mesenchymal stem cells very well reprogrammed into iPSCs, but these iPSCs also could be reliably differentiated into cardiomyocytes (heart muscle cells, that is) that had no detectable signs of the transgenes that were used to reprogram them, and, also, had normal karyotypes. Karyotypes are spreads of a cell’s chromosomes, and the chromosome spreads of these reprogrammed cells were normal.

As to what kinds of heart muscle cells were made, these cells showed the usual types of calcium cycling common to heart muscle cells. These cells also beat faster when they were stimulated with epinephrine-like molecules (isoproterenol in this case). Interestingly, the heart muscle cells were a mixed population of ventricular cells that form the large, lower chambers of the heart, atrial cells, that form the small, upper chambers of the heart, and pacemaker cells that spontaneously form their own signals to beat.

This paper demonstrated that second-trimester human amniotic fluid cells can be reliably reprogrammed into iPSCs that can be reliably differentiated into heart muscle cells that are free of reprogramming factors. This approach does have the potential to produce patient-specific, therapeutic-grade heart muscle cells for treatment before the child is even born.

Some caveats do exist. The use of the Sendai virus means that cells have to be passaged several times to rid them of the viral DNA sequences. Also, to make these clinical-grade cells, all animal produces in their production must be removed. Tremendous advances have been made in this regard to date, but those advancements would have to be applied to this procedure in order to make cells under Good Manufacturing Practices (GMP) standards that are required for clinical-grade materials. Finally, neither of these mothers had children who were diagnosed with a CHD. Deriving heart muscle cells from children diagnosed with a CHD and showing that such cells had the ability to improve the function of the heart of such children is the true test of whether or not this procedure might work in the clinic.

Intravenous Preconditioned Mesenchymal Stem Cells from Donors Improve the Heart Function of Heart Failure Patients

CardioCell is a global biotechnology company that was founded in 2013 in San Diego, California. CardioCell specializes in ischemia-tolerant mesenchymal stem cells (itMSCs). These stem cells are derived from bone marrow-derived mesenchymal stems extracted from healthy donors. However, after isolation, these cells are grown in low-oxygen conditions, which induces the expression of genes that allow cells to adapt to stressful, oxygen-poor conditions.

Non-ischemic dilated cardiomyopathy (NIDCM) is a progressive disorder with no current cure, often culminating in heart transplantation. Because the heart has enlarged, there are areas where the blood supply of the heart fails to properly provide oxygen to the tissues. Without proper muscular support, the walls of the heart begin to thin and the blood supply becomes less and less adequate to the task of feeding the heart muscle. Also, the heart of a patient experiencing chronic heart failure also seems to have some low-level of inflammation that slowly damage the heart (Circ Res. 2016;119(1):159-76). Stem cell treatments might help ameliorate the physiological quandary in which the heart finds itself, but these oxygen-poor areas of the heart are inimical to stem cell survival and flourishing. Therefore, itMSCs stand a better chance of surviving when implanted into a damaged heart than non-conditioned stem cells. Experiments in laboratory animals have confirmed that itMSCs show a greater ability to seek out and find the damaged heart and engraft into the heart at higher rates than MSCs grown under normal culture conditions (see PLoS One. 2015 Sep 18;10(9):e0138477; Stem Cells. 2015 Jun;33(6):1818-28). These itMSCs also secrete higher levels of growth factors and angiogenic factors than normal MSCs. On the strength of these laboratory and animal-based studies itMSCs are now in the process of being tested as a treatment for heart attack patients.

CardioCell has sponsored a single-blind, placebo-controlled, crossover, randomized phase II-a trial of patients with NIDCM who have an ejection below 40% (the ejection fraction refers to the average percentage of blood pumped from the left ventricle at each contraction. The average ejection from for a healthy individual is about 65% or so).  The results of this study were published in the journal Circulation Research (;

Patients who volunteered for this study were randomly assigned to group I or group II. Group I patients received intravenous infusions of one and a half-million itMSCs per kilogram body weight. Group II received the placebo. There were 22 patients in all, and 10 received the itMSCs and 10 received the placebo. Since this was a crossover trial, after 90 days, patients in group I received he placebo and group II received the intravenous itMSCs. After crossover, safety and efficacy data were available for all 22 itMSC patients.

With respect to safety issues, there were no major differences in the number of deaths, hospitalizations, or serious adverse events between the two treatments. With respect the efficacy, the data is but more difficult to analyze. In the first place, when it comes to changes in the ejection fraction of the left ventricle from the originally measured baseline, there were no statistically significant changes between the two treatments. The same could be said for the volume of the left ventricle. This is an unfortunately finding, since heart failure includes a decrease in the ejection fraction of the heart and stretching and dilation of the ventricles. Stem cell treatments, if they are to properly treat heart failure, should increase the ejection fraction of the heart and reduce the dilation of the left ventricle. However, there might be more to these data than originally meets the eye. When it came to patient performance, the data was much more hopeful. Compared to patients who received the placebo, patients who received the itMSCs significantly increased the distance they were able to walk during 6-minutes. Patients who had received the itMSCs walked an average of 36.47 longer meters than patients who had received the placebo. Additionally, patients were also given a commonly-used survey, called the Kansas City Cardiomyopathy clinical summary. This survey is a 23-item, self-administered instrument that quantifies physical function, symptoms (frequency, severity and recent change), social function, self-efficacy and knowledge, and quality of life. Administration of this survey to both sets of patients revealed that patients who had received the itMSCs consistently and statistically significantly scored higher on this survey than those patients who received the placebo. The same was also demonstrated for particular functional status tests. Therefore, when it came to how well patients felt and well they functioned, itMSC treatments seemed to excel significantly better than placebo.

Given the ability of MSCs to suppress inflammation, and given the tendency for patients with heart failure to suffer from chronic inflammation of the heart, individual patients were measured for their degree of inflammation. There was an inverse relationship between the degree of inflammation in a patient and their ejection fraction; the lower their level of inflammation, the higher their ejection fraction.

Thus this study seems to suggest that treatment of heart failure with itMSCs is indeed safe. These treatments also did reduce inflammation in heart failure patients and these reductions in inflammation were also associated with improvements in health status and functional capacity.

Capricor Therapeutics Enrolls Patients in HOPE Clinical Trial

The Beverly Hills-based biotechnology company Capricor Therapeutics, Inc. (CAPR) has announced the enrollment of 25 patients for their randomized Phase 1/2 HOPE-Duchenne clinical trial.

“HOPE” stands for “Halt cardiomyOPathy progrEssion in Duchenne” Muscular Dystrophy. The HOPE trial will evaluate the company’s CAP-1002 investigational cardiac cell therapy in patients suffering from Duchenne muscular dystrophy (DMD)-associated cardiomyopathy. If all goes as planned, CAPR expects to the first data points from this trial in six months (first quarter of 2017).

DMD most seriously affects skeletal muscle, but the disease can also devastate heart muscle. In fact, the most common cause of death from DMD results from the consequences of the disease on heart muscle.

The HOPE trial will assess the safety and efficacy of CAP-1002 in these 25 patients.

In DMD patients, scar tissue gradually accumulates in the heart, which leads to a deterioration of cardiac function.

CAP-1002 consists of cells donated from the hearts of healthy volunteers. These “cardiosphere-derived cells” or CDCs, have been shown by work in the laboratory of Dr. Eduardo Marbán, Director of the Heart Institute at Cedars-Sinai Medical Center, to reduce scar tissue in damaged hearts and improve heart function in studies with laboratory animals. Furthermore, a clinical study with CDCs, the CADUCEUS study, showed that the reduction of heart scar tissue in patients given infusions of CDCs. Therefore CAD-1002 might be the only therapeutic agent that can potentially reduce scar tissue in the damaged heart.

The HOPE trial enrolled 25 boys with DMD who were at least 12 years of age at the time of screening and who show signs of DMD-associated cardiomyopathy. These boys all have significant scar tissue in at least four left ventricular segments, according to magnetic resonance imaging (MRI) scans.

Of these 25 subjects, 13 subjects were randomly assigned to receive CAP-1002 by means of intracoronary infusion into each of the three main coronary arteries in a single procedure.

The 12 subjects randomized to the control arm received usual care and received no such infusion.

Efficacy of CAD-1002 will be assessed by means of specified secondary outcome measures that include absolute and relative changes in cardiac scar tissue and cardiac function as measured by MRI, performance on the Six-Minute Walk Test (6MWT) and the Performance of the Upper Limb (PUL), and scoring on the Pediatric Quality of Life Inventory (PedsQL).

The HOPE trial is a multicenter study; it is being conducted at Cincinnati Children’s Hospital Medical Center in Cincinnati, Ohio, Cedars-Sinai Heart Institute in Los Angeles, Calif., and the University of Florida in Gainesville, Fla.

DMD is a genetically inherited condition. The dystrophin gene that is abnormal in DMD patients is on the X chromosome, and therefore, the vast majority of DMD patients are male. DMD afflicts approximately 20,000 boys and young men in the U.S. The dystrophin complex is a structural component of muscles, integral to the integrity of muscle fibers. Abnormalities in dystrophin leads to chronic skeletal and cardiac muscle damage.

Induced Pluripotent Stem Cell-Based Model System of Hypertrophic Cardiomyopathy Provides Unique Insights into Disease Pathology

A research team at the Icahn School of Medicine at Mount Sinai led by Bruce Gelb created a model of hypertrophic cardiomyopathy (HCM) by using human induced pluripotent stem cells.

Patients who suffer from an extreme thickening of the walls of the heart exhibit HCM. This excessive heart thickening is associated with a several rare and common illnesses. There is a strong genetic component to the risk for developing HCM. Can stem cell-based model system be used to study the genetics of HCM?

The answer to this question seems to be yes, since laboratory-generated induced pluripotent stem cells lines that have been differentiated into heart cells that, in many cases, closely resemble human heart tissue. Studies with such stem cell-based model systems have reaped useful insights into disease mechanisms (see F Kamdar, et al., J Card Fail. 2015 Sep;21(9):761-70; Lee YK, Ng KM, Tse HF. J Biomed Nanotechnol. 2014 Oct;10(10):2562-85).

In this paper, Bruce Gelb and his colleagues examined a genetic disorder called cardiofaciocutaneous syndrome (CFC). CFC is caused by mutations in a gene called BRAF. It is a rare condition that affects fewer than 300 people worldwide, and causes head, face, skin, and muscular abnormalities, including abnormalities of the heart.

Gelb and his coworkers isolated skin cells from three CFC patients and reprogrammed them into induced pluripotent stem cells, which were then differentiated into heart cells. In this disease model system, the heart muscle cells enlarged, but this seemed to be due to the interaction of the heart muscle cells with heart-specific fibroblasts. Fibroblasts constitute a significant portion of total heart tissue, even though the heart muscle cells are responsible for the actual pumping activity of the heart. In their model system, Gelb and others observed that these fibroblast-like cells produce an excess of a protein growth factor called TGF-beta, which causes the cardiomyocytes to undergo hypertrophy or abnormal enlargement.

This model system has relevance for research on several related and more common genetic disorders, including Noonan syndrome, which is characterized by unusual facial features, short stature, heart defects, and skeletal malformations.

There is no cure for HCM in patients with these related genetic conditions, but if these findings are correct, then scientists might be able to treat HCM by blocking specific cell signals. This is something that scientists already know how to do. Approximately 40 percent of patients with CFC suffer from HCM (two of the three participants in this study had HCM). This suggests a pathogenic connection, though the link has never been adequately researched.

“We believe this is the first time the phenomenon has been observed using a human induced pluripotent stem cell model of the disease,” said Bruce Gelb.

Please see Rebecca Josowitz et al., “Autonomous and Non-Autonomous Defects Underlie Hypertrophic Cardiomyopathy in BRAF-Mutant hiPSC -Derived Cardiomyocytes,” Stem Cell Reports, 2016; DOI: 10.1016/j.stemcr.2016.07.018.