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.”

Small Molecule Supercharges Human Cardiac Stem Cells

HO-1 or heme oxygenase is an enzyme that degrades heme groups to biliverdin, iron, and carbon monoxide. It is induced in cells in response to oxidative stress. Overexpression of HO-1 can make cells more resistant to oxidative stress. The highest levels of HO-1 are found in the spleen, where old red blood cells are sequestrated and destroyed.

Mesenchymal stem cells (MSCs) from bone marrow have been genetically engineered to overexpress HO-1 survive much better when implanted into the hearts of animals that have recently suffered a heart attack (Zeng B, et Al, Biomed Sci. 2010 Oct 7;17:80; Yang JJ et al Tohoku J Exp Med. 2012;226(3):231-41). Such cells also increase the density of blood vessels in infarcted tissue, and HO-1 has been postulated to increase blood vessel production (Jang YB et al Chin Med J (Engl). 2011 Feb;124(3):401-7).

These previous experiments show that HO-1 can increase the survival and therapeutic abilities of MSCs. Can increasing the levels of HO-1 do the same for other types of stem cells?

Stuart Atkinson at the Stem Cell Portal web site has highlighted a new paper that was published in the journal Stem Cells that has examined increasing the levels of HO-1 in Cardiac Stem Cells (CSCs).

CSCs are a resident stem cell in the heart that can be isolated from heart patients during heart surgeries. Animal studies and clinical trials have shown that implantation of CSCs soon after a heart attack can produce significant increases in heart function (Bearzi C, et al. Proc Natl Acad Sci U S A 2007;104:14068-14073; Bolli R, et al Lancet. 2011 Nov 26;378(9806):1847-57). Unfortunately, the success of this clinical has been called into questioned by some problems with the data reported in this paper. However, animal studies suggest that the effectiveness of CSCs is compromised by their limited ability to survive in the heart after a heart attack (Hong KU, et al. PLoS One 2014;9:e96725). Therefore, increasing the survival of CSCs might increase their therapeutic efficacy.

Atkinson notes that the compound cobalt protoporphyrin (CoPP) can induce the expression of higher levels of HO-1 and thereby increase the resistance of the cells to oxidative stress and augment cell survival. Therefore, Robert Bolli from the University of Louisville, Kentucky and his colleagues, in collaboration with researchers from the Albany Medical College have treated CSCs with CoPP and these tested their ability to heal the heart after a heart attack.

Bolli and others isolated human CSCs from patients undergoing CABG (cardiac artery bypass graft) surgery, and grew them in culture to beef up the numbers of cells. After a short time in culture, the CSCs were incubated with CoPP for 12 hours. Then Bolli and his team transplanted these human CSCs that were also labeled with green fluorescent protein (GFP) into the hearts of mice that had suffered rather massive heart attacks and had undergone 35 days of reperfusion. The GFP allowed Bolli and others to detect the presence of the implanted CSCs in the rodent heart tissue.

When these hearts of these mice were examined one and five weeks after CSC transplantation, the CoPP-treated CSCs showed substantially higher levels of survival in the mouse hearts. The other two groups of mice included those transplanted with non-pretreated CSCs, and mice treated with the culture medium used to grow the CSCs, and the pretreated CSCs survival significantly better than the non-pretreated CSCs.

CoPP pretreatment seems to augment cell survival, but do the surviving cells increase heart function? Bolli and others used echocardiogram to measure heart function, and echocardiographic assessment 5 weeks after CSC transplantation showed that the CoPP-preconditioned CSCs elicited greater improvement in remodeling of the left ventricle. Additionally, the hearts of the animals that received CoPP-pretreated CSCs showed improved movement of the walls of the heart during its pumping cycle, and better overall performance of the heart in general. Both pretreated and the non-pretreated CSCs, but not CSC culture growth medium shrank the amount of scar tissue in the heart and grew new heart tissue. However, The CoPP-pretreated CSCs were obviously superior to the non-pretreated CSCs at increasing the mass of heart muscle (see here for pictures).

These experiments might very well unravel a burning controversy surrounding CSCs. Bolli’s experiment show that can definitely grow new heart muscle. However, the bulk of the experiments with CSCs strongly suggest that these cells improve heart function by secreting pro-healing molecules without directly contributing to the regrowth of heart muscle. These papers probably observed the effects of CSCs that were transplanted into the heart, but did not survive very long. Bolli and his colleagues, on the other hand, were able to implant CSCs and survived for a much longer time in the hearts. Incidentally, Bolli and his team showed that the implanted CSCs expressed heart muscle-specific genes, which corroborated that these cells were differentiating into heart muscle cells, even though the proportion of cells that formed new heart muscle was relatively small.

In summary, CoPP pretreatment of cell seems to be feasible, safe, and effective as a means to improve CSC-based therapy. Even though It is likely that paracrine mechanisms are essential for CSC-based healing, the ability of CSCs to differentiate into heart muscle cells also seems to be an essential part of the means by which CSCs heal the heart after a heart attack. Thus more work is certainly warranted, but this is a fine start to what might be a simple, but effective way to increase the effectiveness of our own CSCs.

Cardiac Stem Cells or their Exosomes Heal Heart Damage Caused by Duchenne Muscular Dystrophy

One of the research institutions that has been at the forefront of developing investigational stem cell treatments for heart attack patients is The Cedars-Sinai Heart Institute. Recently, a research team at Cedars-Sinai Heart Institute (CSHI) has injected cardiac stem cells into the hearts of laboratory mice afflicted with a rodent form of Duchenne muscular dystrophy. This disease can also adversely affect the heart, and these stem cell injections actually improved the heart function of these laboratory animals and resulted in greater survival rates for those mice. This work might provide the means to extend the lives and improve the quality of life of patients with this chronic muscle-wasting disease.

The CSHI team presented their results at the American Heart Association Scientific Sessions in Chicago. Their results clearly demonstrated that once laboratory mice with Duchenne muscular dystrophy were infused with cardiac stem cells, the animals showed progressive and significant improvements in heart function and increased exercise capacity.

Specifically, 78 lab mice that had been given laboratory-induced heart attacks were injected with their own cardiac stem cells, and over the next three months, these mice demonstrated improved pumping ability and exercise capacity in addition to a reduction in heart-specific inflammation. The CSHI team also discovered that the stem cells work indirectly, by secreting tiny vesicles called exosomes that are filled with molecules that induce tissue healing. When these exosomes were purified and administered alone, they reproduced the key benefits of the cardiac stem cells.

Apparently, this particular procedure could be ready for testing in human clinical studies as soon as next year.

Duchenne muscular dystrophy or DMD is a genetic disease that results from mutations in a gene found on the X chromosome in humans. DMD affects 1 in 3,600 boys and is a neuromuscular disease caused by abnormalities in a muscle protein called dystrophin.  Because dystrophin is an important structural protein for muscle that anchors muscle to other muscles and to the substratum, deficiencies for functional copies of the dystrophin protein cause progressive muscle wasting, destruction, and muscle weakness.

Dystrophin acts as an important link between the internal cytoskeleton and the extracellular matrix. Neuronal nitric oxide synthase (nNOS) binds to α-syntrophin but also has a binding site in repeat 17 of the rod domain of dystrophin (see Fig. 2A for details of dystrophin domains). αDG, α-dystroglycan; βDG, β-dystroglycan
Dystrophin acts as an important link between the internal cytoskeleton and the extracellular matrix. Neuronal nitric oxide synthase (nNOS) binds to α-syntrophin but also has a binding site in repeat 17 of the rod domain of dystrophin (see Fig. 2A for details of dystrophin domains). αDG, α-dystroglycan; βDG, β-dystroglycan.  See here

The majority of DMD patients lose their ability to walk by twelve years of age, although the severity of the disease varies from patient to patient. The average life expectancy is about 25, and the cause of death is usually heart failure. Dystrophin deficiency causes heart muscle weakness, and, ultimately, heart insufficiency, since the chronic weakness of the heart muscle prevents the heart from pumping enough blood to maintain a regular heart rhythm and provide for the needs of the rest of the body. Such a heart condition is called “cardiomyopathy.”

“Most research into treatments for Duchenne muscular dystrophy patients has focused on the skeletal muscle aspects of the disease, but more often than not, the cause of death has been the heart failure that affects Duchenne patients,” said Eduardo Marbán, MD, PhD, who is the director of the CSHI and the principal investigator of this particular study. “Currently, there is no treatment to address the loss of functional heart muscle in these patients.”

In 2009, Marbán and his team completed the world’s first procedure in which a patient’s own heart tissue was used to grow specialized heart stem cells. Stem cells from the heart were isolated, cultured, and then injected back into the patient’s heart in order to repair and regrow healthy heart muscle that had been injured by a heart attack. Results, Marbán and his colleagues published these results in The Lancet in 2012, and also demonstrated that one year after their patients had received the experimental stem cell treatment, they showed significant reductions in the size of the heart scar that had been produced by their heart attacks.

Earlier this year, CSHI researchers commenced a new clinical trial entitled “ALLSTAR,” which stands for Allogeneic Heart Stem Cells to Achieve Myocardial Regeneration (Clinical trial number NCT01458405). In this study, heart attack patients are given injections of stem cells from healthy donors, which should work better than the patient’s own stem cells, which were damaged by the heart attack.

CSHI has recently opened the nation’s first Regenerative Medicine Clinic, which is designed to match heart and vascular disease patients with the appropriate stem cell clinical trial being conducted at CSHI and other institutions.

“We are committed to thoroughly investigating whether stem cells could repair heart damage caused by Duchenne muscular dystrophy,” Marbán said.

The protocols for growing cardiac-derived stem cells were developed by Marbán when he was on the faculty of Johns Hopkins University. Johns Hopkins has filed for a patent on that intellectual property and has licensed it to Capricor, a company in which Cedars-Sinai and Marbán have a financial interest. Capricor is providing funds for the ALLSTAR clinical trial at Cedars-Sinai.

Growth Factor Delivery Stimulates Endogenous Heart Repair After Heart Attacks in Pigs

Steven Chamulean and his colleagues at the University Medical Center Utrecht in Holland have examined the use of growth factors to induce healing in the heart after a heart attack. Because simply applying growth factors to the heart will cause them to simply be washed out, Chamulean and his coworkers embedded the growth factors in a material called hydrogel. They were able to measure how long the implanted growth factors lasted. As it turns out, when the growth factors were embedded in the hydrogel, they lasted for four days, and the hydrogel caused the growth factors to spread out into heart tissue with a gradient with the highest concentration at the site of injection (see Bastings, et al., Advanced Healthcare Materials 2013 doi: 10.1002/adhm.201300076).

In his new publication in the Journal of Cardiovascular Translational Research, Chamulean and his group used a new hydrogen called UPy to into which they embedded their growth factors. UPy stands for ureido-pyrimidinone end-capped poly(ethylene glycol) polymer. At the pH of our bodies, UPy hydrogels form a gel-like material made of fibers. When the pH changes, the gel becomes liquid. They embedded the growth factors insulin-like growth factor-1 (IGF-1), and hepatocyte growth factor (HGF).

The experimental design of this paper used pigs that were given heart attacks and then reperfused 75 minutes later. One month later, the animals were broken into three groups: just hydrogel, hydrogel with growth factors embedded in it, and growth factors injected into other heart without hydrogel. One month later, the animals were examined for their heart function, and then the animals were sacrificed to examine their heart tissue.

In every case, the hearts treated with only the hydrogel did the poorest of the three groups. The animals injected with gel-less growth factors did better than the controls, but those animals treated with growth factors embedded in UPy hydrogel did the best. The physiological indicators of the hearts from the animals treated with UPy embedded with IGF-1 and HGF improved significantly more than the controls that were treated with only UPy hydrogel. The hearts from animals treated with IGF and HGF without hydrogels improved over controls, by not nearly as well as those treated with growth factor-embedded UPy hydrogels.

When the hearts were examined even more surprises were observed. The animals with hearts that had been treated with UPy + growth factors did not show the enlargement observed in the control hearts. This is significant, because enlargement of the heart is a side effect for a heart attack and is the sign of heart failure. The UPy + growth factor hearts also displayed many signs of dividing cells; far more than hearts from the other two groups. Since the heart has its own resident stem cell population, these growth factors stimulated these stem cells to divide and form new heart muscle, and new blood vessels. Blood vessel density was much higher in the UPy + growth factor group and the pressure against which blood flowed in these hearts was substantially less in this groups, demonstrating that not only was the blood vessel density higher, but blood flow through these vessel networks was much more efficient. There was also plentiful evidence of the formation of new muscle in the UPy + growth factor group. When these hearts were also stained for c-kit, which is a cell surface marker for cardiac stem cells, the UPy + growth factor hearts had lots of them – much more than the other two groups.

This paper reports significant findings because the resident stem cell population in the heart was actively mobilized without having to extract them by means of a biopsy. There is also evidence from Torella and others that IGF-1 and HGF can reactivate the sleeping cardiac stem cells of aged laboratory animals (Circulation Research 2004 94: 514-524). The UP{y hydrogels are well tolerated and are biodegradable. They provide a medium that stays in place and releases embedded growth factors in a sustained manner. The results in this paper provide the rationale to develop growth factor therapy for human patients.

Making Cardiac Stem Cells That are a Notch Above the Rest

The human heart has a stem cell population all its own. This stem cell population replaces heart cells at a leisurely rate throughout the life of the heart. Unfortunately, a heart attack overwhelms this repair system, and the heart simply lacks the capacity to heal itself to beyond particular limits.

However, there is the hope that physicians will one day be able to augment the healing capacity of the heart, and a few clinical trials and several animal experiments strongly suggest that this is the possible.

A new paper by Yoshiki Sawa at and his team from Osaka University has examined a way to increase the healing capabilities of human cardiac stem cells (CSCs).

In this paper, which was published in the journal Circulation, isolated CSCs from a 12-year old patient and grown in culture. However, the cells were grown in several different types of culture conditions. The density at which cells are grown can affect their biological characteristics. Therefore, Sawa and his group plated these cells at four different densities; single, low, mid and high densities. The single, low and med density-grown cells divided faster than the cells grown as high density. Also, the cells grown at lower cell densities retained their ability to form either heart muscle or blood vessels whereas the cells grown at high densities stated to make blood vessels en mass.

When scientists from Sawa’s group examined why the cells grown at high densities turned into blood vessel cells, they discovered that these cells activated a signaling pathway called the NOTCH pathway. Activation of the NOTCH pathway turned the cells into blood vessel-making cells and slowed their growth in culture.

JCS slide template

Presumably, the faster-growing, more plastic cells would be better for regenerative treatments that the slower-growing, less plastic cells. To test this hypothesis, Sawa and others transplanted cultured CSCs grown as different densities into the hearts of rats that had suffered a recent heart attack. They are used CSCs grown at high densities, but had been treated with a drug that inhibits the NOTCH pathway.

The results were remarkable. The lower the densities at which the cells were grown, the better they repaired the heart. However, the high-density cells grown in the presence of a NOTCH inhibitor (called GSI), were just as good at repairing the heart as the cells grown at low density. While the cells grown in the presence of GSI at high density still grew slowly, they showed an enhanced capacity to induce the formation of new blood vessels in the damaged heart tissue and form new heart muscle.

In conclusion these authors state: “Therapeutic effects of CSC-transplantation for heart disease may be enhanced by reducing NOTCH signaling in CSCs.”

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

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

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

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

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

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

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

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


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

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

Umbilical Cord Stem Cells Preserve Heart Function After a Heart Attack in Mice

A consortium of Portuguese scientists have conducted an extensive examination of the effects of mesenchymal stromal cells from umbilical cord on the heart of mice that have suffered a massive heart attack. Even more remarkable is that these workers used a proprietary technique to harvest, process, and prepare the umbilical cord stem cells in the hopes that this technique would give rise to a commercial product that will be tested in human clinical trials,

Human umbilical cord tissue-derived Mesenchymal Stromal Cells (MSCs) were obtained by means of a proprietary technology that was developed by a biomedical company called ECBio. Their product,, UCX®, consists of clean, high-quality, umbilical cord stem cells that are collected under Good Manufacturing Practices. The use of Good Manufacturing Practice means that UCX is potentially a clinical-grade product. Thus, this paper represents a preclinical evaluation of UCX.

This experiments in this paper used standard methods to give mice heart attacks that were later received injections of UCX into their heart muscle. The same UCX cells were used in experiments with cultured cells to determine their effects under more controlled conditions.

The mice that received the UCX injections into their heart muscles after suffering from a large heart attack showed preservation of heart function. Also, measurements of the numbers of dead cells in the heart muscle of heart-sick mice that did and did not receive injections of umbilical cord cells into their hearts showed that the umbilical cord stem cells preserved heart muscle cells and prevented them from dying. Additionally, the implanted umbilical cord MSCs induced the growth and formation of many small blood vessels in the infarcted area of the heart. This prevented the heart from undergoing remodeling (enlargement), and preserved heart structure and function.

When subjected to a battery of tests on cultured cells, UCX activated cardiac stem cells, which are the resident stem cell population in the heart. Implanted UCX cells activated the proliferation of cardiac stem cells and their differentiation into heart muscle cells. There was no evidence that umbilical cord MSCs differentiated into heart muscle cells and engrafted into the heart. Rather UCX seems to help the heart by means of paracrine mechanisms, which simply means that they secrete healing molecules in the heart and help the heart heal itself.

In conclusion, Diana Santos Nascimento, the lead author of this work, and her colleagues state that, “the method of UCX® extraction and subsequent processing has been recently adapted to advanced therapy medicinal product (ATMP) standards, as defined by the guideline on the minimum quality data for certification of ATMP. Given that our work constitutes a proof-of-principle for the cardioprotective effects UCX® exert in the context of MI, a future clinical usage of this off-the-shelf cellular product can be envisaged.”

Preclinical trials with larger animals should come next, and after that, hopefully, the first human clinical trials will begin.