Effect of transendocardial delivery of autologous bone marrow mononuclear cells on functional capacity, left ventricular function, and perfusion in chronic heart failure: the FOCUS-CCTRN trial

The Clinical Status of Stem Cell Therapy for Ischemic Cardiomyopathy

Ischemic cardiomyopathy (ICM) is becoming a leading cause of morbidity and mortality in the whole world. Stem cell-based therapy is emerging as a promising option for treatment of ICM. Several stem cell types including cardiac-derived stem cells (CSCs), bone marrow-derived stem cells, mesenchymal stem cells (MSCs), skeletal myoblasts (SMs), and CD34(+) and CD 133(+) stem cells have been applied in clinical researches. The clinical effect produced by stem cell administration in ICM mainly depends on the transdifferentiation and paracrine effect. One important issue is that low survival and residential rate of transferred stem cells in the infracted myocardium blocks the effective advances in cardiac improvement. Many other factors associated with the efficacy of cell replacement therapy for ICM mainly including the route of delivery, the type and number of stem cell infusion, the timing of injection, patient's physical condition, the particular microenvironment onto which the cells are delivered, and clinical condition remain to be addressed. Here we provide an overview of the pros and cons of these transferred cells and discuss the current state of their therapeutic potential. We believe that stem cell translation will be an ideal option for patients following ischemic heart disease in the future.

Cardiac tissue engineering and regeneration using cell-based therapy

Stem cell therapy and tissue engineering represent a forefront of current research in the treatment of heart disease. With these technologies, advancements are being made into therapies for acute ischemic myocardial injury and chronic, otherwise nonreversible, myocardial failure. The current clinical management of cardiac ischemia deals with reestablishing perfusion to the heart but not dealing with the irreversible damage caused by the occlusion or stenosis of the supplying vessels. The applications of these new technologies are not yet fully established as part of the management of cardiac diseases but will become so in the near future. The discussion presented here reviews some of the pioneering works at this new frontier. Key results of allogeneic and autologous stem cell trials are presented, including the use of embryonic, bone marrow-derived, adipose-derived, and resident cardiac stem cells.

Bone marrow-derived mesenchymal stromal cell treatment in patients with severe ischaemic heart failure: a randomized placebo-controlled trial (MSC-HF trial)

AIMS

Regenerative treatment with mesenchymal stromal cells (MSCs) has been promising in patients with ischaemic heart failure but needs confirmation in larger randomized trials. We aimed to study effects of intra-myocardial autologous bone marrow-derived MSC treatment in patients with severe ischaemic heart failure.

METHODS AND RESULTS

The MSC-HF trial is a randomized, double-blind, placebo-controlled trial. Patients were randomized 2 : 1 to intra-myocardial injections of MSC or placebo, respectively. The primary endpoint was change in left ventricular end-systolic volume (LVESV), measured by magnetic resonance imaging or computed tomography at 6 months follow-up. Sixty patients aged 30-80 years with severe ischaemic heart failure, New York Heart Association (NYHA) classes II-III, left ventricular ejection fraction (LVEF) <45% and no further treatment options were randomized. Fifty-five patients completed the 6-month follow-up (37 MSCs vs. 18 placebo). At 6 months, LVESV was reduced in the MSC group: -7.6 (95% CI -11.8 to -3.4) mL (P = 0.001), and increased in the placebo group: 5.4 (95% CI -0.4 to 11.2) mL (P = 0.07). The difference between groups was 13.0 (95% CI 5.9-20.1) mL (P = 0.001). Compared with placebo, there were also significant improvements in LVEF of 6.2% (P<0.0001), stroke volume of 18.4 mL (P < 0.0001), and myocardial mass of 5.7 g (P = 0.001). No differences were found in NYHA class, 6-min walking test and Kansas City cardiomyopathy questionnaire. No side effects were identified.

CONCLUSION

Intra-myocardial injections of autologous culture expanded MSCs were safe and improved myocardial function in patients with severe ischaemic heart failure.

STUDY REGISTRATION NUMBER

NCT00644410 (ClinicalTrials.gov).

Drug and cell delivery for cardiac regeneration

The spectrum of ischaemic cardiomyopathy, encompassing acute myocardial infarction to congestive heart failure is a significant clinical issue in the modern era. This group of diseases is an enormous source of morbidity and mortality and underlies significant healthcare costs worldwide. Cardiac regenerative therapy, whereby pro-regenerative cells, drugs or growth factors are administered to damaged and ischaemic myocardium has demonstrated significant potential, especially preclinically. While some of these strategies have demonstrated a measure of success in clinical trials, tangible clinical translation has been slow. To date, the majority of clinical studies and a significant number of preclinical studies have utilised relatively simple delivery methods for regenerative therapeutics, such as simple systemic administration or local injection in saline carrier vehicles. Here, we review cardiac regenerative strategies with a particular focus on advanced delivery concepts as a potential means to enhance treatment efficacy and tolerability and ultimately, clinical translation. These include (i) delivery of therapeutic agents in biomaterial carriers, (ii) nanoparticulate encapsulation, (iii) multimodal therapeutic strategies and (iv) localised, minimally invasive delivery via percutaneous transcatheter systems.

“Second-generation” stem cells for cardiac repair

Over the last years, stem cell therapy has emerged as an inspiring alternative to restore cardiac function after myocardial infarction. A large body of evidence has been obtained in this field but there is no conclusive data on the efficacy of these treatments. Preclinical studies and early reports in humans have been encouraging and have fostered a rapid clinical translation, but positive results have not been uniformly observed and when present, they have been modest. Several types of stem cells, manufacturing methods and delivery routes have been tested in different clinical settings but direct comparison between them is challenging and hinders further research. Despite enormous achievements, major barriers have been found and many fundamental issues remain to be resolved. A better knowledge of the molecular mechanisms implicated in cardiac development and myocardial regeneration is critically needed to overcome some of these hurdles. Genetic and pharmacological priming together with the discovery of new sources of cells have led to a “second generation” of cell products that holds an encouraging promise in cardiovascular regenerative medicine. In this report, we review recent advances in this field focusing on the new types of stem cells that are currently being tested in human beings and on the novel strategies employed to boost cell performance in order to improve cardiac function and outcomes after myocardial infarction.

Effect of aging on human mesenchymal stem cell therapy in ischemic cardiomyopathy patients

BACKGROUND

The role of patient age in the efficacy of mesenchymal stem cell (MSC) therapy in ischemic cardiomyopathy (ICM) is controversial.

OBJECTIVES

This study sought to determine whether the therapeutic effect of culture-expanded MSCs persists, even in older subjects.

METHODS

Patients with ICM who received MSCs via transendocardial stem cell injection (TESI) as part of the TAC-HFT (Transendocardial Autologous Cells in Ischemic Heart Failure) (n = 19) and POSEIDON (Percutaneous Stem Cell Injection Delivery Effects on Neomyogenesis) (n = 30) clinical trials were divided into 2 age groups: younger than 60 and 60 years of age and older. Functional capacity was measured by 6-min walk distance (6MWD) and quality of life using the Minnesota Living With Heart Failure Questionnaire (MLHFQ) score, measured at baseline, 6 months, and 1 year post-TESI. Various cardiac imaging parameters, including absolute scar size, were compared at baseline and 1 year post-TESI.

RESULTS

The mean 6MWD was similar at baseline and increased at 1 year post-TESI in both groups: 48.5 ± 14.6 m (p = 0.001) for the younger and 35.9 ± 18.3 m (p = 0.038) for the older participants (p = NS between groups). The older group exhibited a significant reduction in MLHFQ score (-7.04 ± 3.54; p = 0.022), whereas the younger than 60 age group had a borderline significant reduction (-11.22 ± 5.24; p = 0.058) from baseline (p = NS between groups). Although there were significant reductions in absolute scar size from baseline to 1 year post-TESI, the effect did not differ by age.

CONCLUSIONS

MSC therapy with TESI in ICM patients improves 6MWD and MLHFQ score and reduces myocardial infarction size. Importantly, older individuals did not have an impaired response to MSC therapy.

The winding road to regenerating the human heart

Regenerating the human heart is a challenge that has engaged researchers and clinicians around the globe for nearly a century. From the repair of the first septal defect in 1953, followed by the first successful heart transplant in 1967, and later to the first infusion of bone marrow-derived cells to the human myocardium in 2002, significant progress has been made in heart repair. However, chronic heart failure remains a leading pathological burden worldwide. Why has regenerating the human heart been such a challenge, and how close are we to achieving clinically relevant regeneration? Exciting progress has been made to establish cell transplantation techniques in recent years, and new preclinical studies in large animal models have shed light on the promises and challenges that lie ahead. In this review, we will discuss the history of cell therapy approaches and provide an overview of clinical trials using cell transplantation for heart regeneration. Focusing on the delivery of human stem cell-derived cardiomyocytes, current experimental strategies in the field will be discussed as well as their clinical translation potential. Although the human heart has not been regenerated yet, decades of experimental progress have guided us onto a promising path.

SUMMARY

Previous work in clinical cell therapy for heart repair using bone marrow mononuclear cells, mesenchymal stem cells, and cardiac-derived cells have overall demonstrated safety and modest efficacy. Recent advancements using human stem cell-derived cardiomyocytes have established them as a next generation cell type for moving forward, however certain challenges must be overcome for this technique to be successful in the clinics.

Human placenta-derived adherent cells improve cardiac performance in mice with chronic heart failure

Human placenta-derived adherent cells (PDACs) are a culture-expanded, undifferentiated mesenchymal-like population derived from full-term placental tissue, with immunomodulatory, anti-inflammatory, angiogenic, and neuroprotective properties. PDA-001 (cenplacel-L), an intravenous formulation of PDAC cells, is in clinical development for the treatment of autoimmune and inflammatory diseases. We tested the therapeutic effects of PDA-001 in mice with chronic heart failure (CHF). Three weeks after transaortic constriction surgery to induce CHF, the mice underwent direct intramyocardial (IM) or i.v. injection of PDA-001 at a high (0.5 × 10(6) cells per mouse), medium (0.5 × 10(5) cells per mouse), or low (0.5 × 10(4) cells per mouse) dose. The mice were sacrificed 4 weeks after treatment. Echocardiography and ventricular catheterization showed that IM injection of PDA-001 significantly improved left ventricular systolic and diastolic function compared with injection of vehicle or i.v. injection of PDA-001. IM injection of PDA-001 also decreased cardiac fibrosis, shown by trichrome staining in the vicinity of the injection sites. Low-dose treatment showed the best improvement in cardiac performance compared with the medium- and high-dose groups. In another independent study to determine the mechanism of action with bromodeoxyuridine labeling, the proliferation rates of endothelial cells and cardiomyocytes were significantly increased by low or medium IM dose PDA-001. However, no surviving PDA-001 cells were detected in the heart 1 month after injection. In vivo real-time imaging consistently revealed that the PDA-001 cells were detectable only within 2 days after IM injection of luciferase-expressing PDA-001. Together, these results have demonstrated the cardiac therapeutic potential of PDA-001, likely through a paracrine effect.

Ultrasound-mediated microbubble destruction enhances the therapeutic effect of intracoronary transplantation of bone marrow stem cells on myocardial infarction

OBJECTIVE

The combination of intracoronary transplantation and ultrasound-mediated microbubble destruction may promote effective and accurate delivery of bone marrow stem cells (BMSCs) into the infarct zone. To test this hypothesis in this study we examined the effectiveness of ultrasound-mediated microbubble destruction in combination with intracoronary transplantation of BMSCs for the treatment of myocardial infarction in canine model of acute myocardial infarction.

METHOD

The dogs were randomly assigned to four groups: PBS, ultrasound-mediated microbubble destruction, BMSCs, BMSCs together with ultrasound-mediated microbubble destruction. At 28 days post-surgery, cardiac function and the percentage of perfusion defect area to total left ventricular perfusion area (DA%) were determined by myocardial contrast echocardiography. Nitro blue tetrazolium staining was performed to determine myocardial infarct size, hematoxylin and eosin staining for assessing microvascular injury, Masson's staining for analyzing myocardial tissue collagen, immunohistochemical analysis of α-actin to measure cardiac contractile function and of BrdU-labeled myocardial cells to measure the number of the BMSCs homing to the infarcted region.

RESULTS

The transplantation of BMSCs significantly improved heart function and DA% (P < 0.05). The group that received ultrasound-mediated microbubble destruction with BMSCs transplantation showed the most improvement in heart function and DA% (P < 0.05). This group also showed a denser deposition of BMSCs in the coronary artery and more BrdU positive cells in the infarcted region, had the maximum number of α-actin positive cells, showed the smallest myocardial infarct area compared to other groups (P< 0.05).

CONCLUSION

Ultrasound-mediated microbubble destruction increases the homing of BMSCs in the target area following intracoronary transplantation, which allows more BMSCs to differentiate into functional cardiomyocytes, thereby reducing myocardial infarct size and improving cardiac function.

Cell-based therapies for cardiac disease: a cellular therapist's perspective

Cell-based therapy is an exciting, promising, and a developing new treatment for cardiac diseases. Stem cell-based therapies have the potential to fundamentally transform the treatment of ischemic cardiac injury and heart failure by achieving what would have been unthinkable only a few years ago-the Holy Grail of myocardial regeneration. Recent therapeutic approaches involve bone marrow (BM)-derived mononuclear cells and their subsets such as mesenchymal stem/stromal cells (MSCs), endothelial progenitor cells as well as adipose tissue-derived MSCs, cardiac tissue-derived stem cells, and cell combinations. Clinical trials employing these cells have demonstrated that cellular therapy is feasible and safe. Regarding delivery methods, the safety of catheter-based, transendocardial and -epicardial stem cell injection has been established. However, the results, while variable, suggest rather modest clinical efficacy overall in both heart failure and ischemic heart disease, such as in acute myocardial infarction. Future studies will focus on determining the most efficacious cell type(s) and/or cell combinations and the most reasonable indications and optimal timing of transplantation, as well as the mechanisms underlying their therapeutic effects. We will review and summarize the clinical trial results to date. In addition, we discuss challenges and operational issues in cell processing for cardiac applications.

Intravenous transplantation of bone marrow mesenchymal stem cells could effectively promote vascularization and skin regeneration in mechanically stretched skin

BACKGROUND

Skin expansion is a procedure that stimulates and promotes skin regeneration by applying continuous mechanical stretching. However, the outcome of treatment is limited by the skin's instinctive regeneration capacity.

OBJECTIVES

To evaluate the impact of intravenous transplantation of bone marrow mesenchymal stem cells (MSCs) on expanded skin regeneration.

METHODS

MSCs from luciferase-Tg Lewis rats were transplanted into a rat tissue expansion model and tracked in vivo by luminescence imaging. At the end of 21 days of skin expansion, the expanded skin was harvested and skin regeneration was evaluated by inflation volume, skin area and thickness. Counting of capillaries and vascular endothelial cell growth factor (VEGF) expression analysis were conducted to assess the impact of MSCs on expanded skin vascularization.

RESULTS

Samples of the skin expansion model from the MSC group were observed to have a significantly higher inflation volume and greater expanded skin area than those from the control group at the end of 21 days' follow-up. In vivo tracing results showed that MSCs were recruited by mechanical stretch and migrated to expanded skin. Migrated MSCs promoted skin vascularization by secreting VEGF and differentiating into CD31+ endothelial cells. Skin sections from the MSC group had a significant advantage in thickness and proliferating cell count, indicating that MSCs effectively enhanced expanded skin regeneration.

CONCLUSIONS

Intravenous transplantation of MSCs could effectively promote expanded skin regeneration. Transplanted MSCs could be recruited by mechanical stretch and subsequent migration to expanded skin. Engrafted MSCs could contribute to vascularization and cell proliferation.

Current evidence of the efficacy of cell-based therapies in heart failure

Heart failure (HF) is the major cause of mortality worldwide. For more than a decade, cell-based therapies have been developed as treatment for heart disease as an alternative to current therapies. Trials and systematic reviews have assessed the safety and efficacy of cell therapies in a diverse number of participants and clinical settings. The present study collated and synthesized evidence from all systematic reviews related to cell-based therapies and HF. A total of 11 systematic reviews were identified through searches of electronic databases up to June 2014. We set out to answer 2 key questions on the efficacy of cell therapies in HF: (1) What is the overall effect of cell therapies on primary outcomes such as left ventricular ejection fraction (LVEF) and mortality? (2) How important is it to define the clinical setting and length of follow-up when assessing cell therapies and HF? There seems to be enough evidence to suggest that cell therapies have a moderate, long-lasting effect on LVEF, but the reduction on the risk of mortality observed by some systematic reviews needs to be confirmed in larger, statistically powered clinical trials. Additionally, and in order to strengthen conclusions, it is important to assess clinical evidence for defined clinical settings and to standardize the length of follow-up when comparing outcome data across several trials and systematic reviews.

Concise review: Engineering myocardial tissue: the convergence of stem cells biology and tissue engineering technology

Advanced heart failure represents a leading public health problem in the developed world. The clinical syndrome results from the loss of viable and/or fully functional myocardial tissue. Designing new approaches to augment the number of functioning human cardiac muscle cells in the failing heart serve as the foundation of modern regenerative cardiovascular medicine. A number of clinical trials have been performed in an attempt to increase the number of functional myocardial cells by the transplantation of a diverse group of stem or progenitor cells. Although there are some encouraging suggestions of a small early therapeutic benefit, to date, no evidence for robust cell or tissue engraftment has been shown, emphasizing the need for new approaches. Clinically meaningful cardiac regeneration requires the identification of the optimum cardiogenic cell types and their assembly into mature myocardial tissue that is functionally and electrically coupled to the native myocardium. We here review recent advances in stem cell biology and tissue engineering and describe how the convergence of these two fields may yield novel approaches for cardiac regeneration.

Effect of repetitive intra-arterial infusion of bone marrow mononuclear cells in patients with no-option limb ischemia: the randomized, double-blind, placebo-controlled Rejuvenating Endothelial Progenitor Cells via Transcutaneous Intra-arterial Supplementation (JUVENTAS) trial

BACKGROUND

Patients with severe limb ischemia may not be eligible for conventional therapeutic interventions. Pioneering clinical trials suggest that bone marrow-derived cell therapy enhances neovascularization, improves tissue perfusion, and prevents amputation. The objective of this trial was to determine whether repetitive intra-arterial infusion of bone marrow mononuclear cells (BMMNCs) in patients with severe, nonrevascularizable limb ischemia can prevent major amputation.

METHODS AND RESULTS

The Rejuvenating Endothelial Progenitor Cells via Transcutaneous Intra-arterial Supplementation (JUVENTAS) trial is a randomized, double-blind, placebo-controlled clinical trial in 160 patients with severe, nonrevascularizable limb ischemia. Patients were randomly assigned to repetitive (3 times; 3-week interval) intra-arterial infusion of BMMNC or placebo. No significant differences were observed for the primary outcome, ie, major amputation at 6 months, with major amputation rates of 19% in the BMMNC versus 13% in the placebo group (relative risk, 1.46; 95% confidence interval, 0.62-3.42). The safety outcome (all-cause mortality, occurrence of malignancy, or hospitalization due to infection) was not significantly different between the groups (relative risk, 1.46; 95% confidence interval, 0.63-3.38), neither was all-cause mortality at 6 months with 5% versus 6% (relative risk, 0.78; 95% confidence interval, 0.22-2.80). Secondary outcomes quality of life, rest pain, ankle-brachial index, and transcutaneous oxygen pressure improved during follow-up, but there were no significant differences between the groups.

CONCLUSIONS

Repetitive intra-arterial infusion of autologous BMMNCs into the common femoral artery did not reduce major amputation rates in patients with severe, nonrevascularizable limb ischemia in comparison with placebo. The general improvement in secondary outcomes during follow-up in both the BMMNC and the placebo group, as well, underlines the essential role for placebo-controlled design of future trials.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00371371.

Serial myocardial perfusion imaging: defining a significant change and targeting management decisions

Myocardial perfusion imaging (MPI) with gated single-photon emission tomography provides important information on the extent and severity of myocardial perfusion abnormalities, including myocardial ischemia. The availability of software for automated quantitative assessment of myocardial perfusion in an objective and more reproducible manner than visual assessment has allowed MPI to be particularly effective in serial evaluation. Serial testing using MPI is widely used in guiding patient care despite the lack of well-defined appropriateness use criteria. This should not be surprising because ischemic heart disease is a life-long malady subject to dynamic changes throughout its natural course and particularly following man-made interventions that may improve or worsen the disease process, such as medical therapy and coronary revascularization. Serial MPI has filled an important clinical gap by providing crucial information for managing patients with changes in clinical presentations or in anticipation of such changes in patients with stable symptoms. In the research arena, serial MPI has been widely applied in randomized controlled trials to study the impact of various medical and interventional therapies on myocardial perfusion, as well as the relative merits of new imaging procedures (hardware and/or software), radiotracers, and stressor agents. Serial testing, however, unlike initial or 1-time testing, has more stringent requirements and is subject to variability because of technical, procedural, interpretational, and biological factors. The intrinsic variability of MPI becomes important in interpreting serial tests in order to define a true change in a given patient and to guide clinical decision making. The purpose of this first comprehensive review on this subject is to illustrate where serial MPI may be useful clinically and in research studies, and to highlight strategies for addressing the various issues that are unique to serial testing in order to derive more valid and robust data from the serial scans.

The role of tissue engineering in cellular therapies for myocardial infarction: a review

Current medical treatments of myocardial infarction (MI) face a serious shortcoming in that they cannot reverse the detrimental effects of ischemia induced necrosis.

Stem cell imaging: from bench to bedside

Although cellular therapies hold great promise for the treatment of human disease, results from several initial clinical trials have not shown a level of efficacy required for their use as a first line therapy. Here we discuss how in vivo molecular imaging has helped identify barriers to clinical translation and potential strategies that may contribute to successful transplantation and improved outcomes, with a focus on cardiovascular and neurological diseases. We conclude with a perspective on the future role of molecular imaging in defining safety and efficacy for clinical implementation of stem cell therapies.

Stem cells in the management of heart failure: what have we learned from clinical trials?

Research shows that various types of stem cells (SCs) have the ability to rebuild damaged heart tissue. The TIME and Late TIME human trials shed light on the optimum timing of SC therapy administration after myocardial damage. The FOCUS study failed to show a substantial positive effect of bone marrow-derived mononuclear cells in patients suffering from ischemic heart failure; however, some completed human trials do show promise, with improvement in cardiac function. Recent clinical trials have identified a subset of marrow cells that was able to stimulate endogenous adult cardiac SCs where cardiac SCs administration showed promise in the SCIPIO trial. This review addresses some of the lessons learned from clinical trials with SC therapy in ischemic heart failure.

New vessel formation in the context of cardiomyocyte regeneration--the role and importance of an adequate perfusing vasculature

The history of revascularization for cardiac ischemia dates back to the early 1960's when the first coronary artery bypass graft procedures were performed in humans. With this 50 year history of providing a new vasculature to ischemic and hibernating myocardium, a profound depth of experience has been amassed in clinical cardiovascular medicine as to what does, and does not work in the context of cardiac revascularization, alleviating ischemia and adequacy of myocardial perfusion. These issues are of central relevance to contemporary cell-based cardiac regenerative approaches. While the cardiovascular cell therapy field is surging forward on many exciting fronts, several well accepted clinical axioms related to the cardiac arterial supply appear to be almost overlooked by some of our current basic conceptual and experimental cell therapy paradigms. We present here information drawn from five decades of the clinical revascularization experience, review relevant new data on vascular formation via cell therapy, and put forward the case that for optimal cell-based cardiac regeneration due attention must be paid to providing an adequate vascular supply.

ST elevation myocardial infarction: recent advances and updates

ST elevation myocardial infarction (STEMI) remains a leading cause of morbidity, mortality and disability worldwide. Statistically, a trend towards improvements in morbidity and mortality has been consistent over the years, which is attributed primarily to the modification of risk factors, healthier lifestyles, treatment advances and better management of door-to-balloon times via STEMI systems. However, a major challenge in the coming years will be the baby boomers (born between the years 1946 and 1964) coming into old age. The first baby boomers turned 65 in year 2011. As the baby boomers age in the coming years, the incidence of coronary heart disease is likely to increase, and so there will be a greater need to have major advances in the management of coronary heart disease in order to deal with this additional incidence. The scope of this article is to review recent advances in the management of STEMI and to provide an updated overview.

Fibrosis and heart failure

The extracellular matrix (ECM) is a living network of proteins that maintains the structural integrity of the myocardium and allows the transmission of electrical and mechanical forces between the myocytes for systole and diastole. During ventricular remodeling, as a result of iterations in the hemodynamic workload, collagen, the main component of the ECM, increases and occupies the areas between the myocytes and the vessels. The resultant fibrosis (reparative fibrosis) is initially a compensatory mechanism and may progress adversely influencing tissue stiffness and ventricular function. Replacement fibrosis appears at sites of previous cardiomyocyte necrosis to preserve the structural integrity of the myocardium, but with the subsequent formation of scar tissue and widespread distribution, it has adverse functional consequences. Continued accumulation of collagen impairs diastolic function and compromises systolic mechanics. Nevertheless, the development of fibrosis is a dynamic process wherein myofibroblasts, the principal cellular elements of fibrosis, are not only metabolically active and capable of the production and upregulation of cytokines but also have contractile properties. During the process of reverse remodeling with left ventricular assist device unloading, cellular, structural, and functional improvements are observed in terminal heart failure patients. With the advent of anti-fibrotic pharmacologic therapies, cellular therapy, and ventricular support devices, fibrosis has become an important therapeutic target in heart failure patients. Herein, we review the current concepts of fibrosis as a main component of ventricular remodeling in heart failure patients. Our aim is to integrate the histopathologic process of fibrosis with the neurohormonal, cytochemical, and molecular changes that lead to ventricular remodeling and its physiologic consequences in patients. The concept of fibrosis as living scar allows us to envision targeting this scar as a means of improving ventricular function in heart failure patients.

Activation of mitochondrial function and Hb expression in non-haematopoietic cells by an EPO inducer ameliorates ischaemic diseases in mice

BACKGROUND AND PURPOSE

Many organs suffer from ischaemic injuries that reduce their ability to generate sufficient energy, which is required for functional maintenance and repair. Erythropoietin (EPO) ameliorates ischaemic injuries by pleiotropic effects. The aim of this study was to investigate the effect and mechanism of a small molecule EH-201, and found it as a potent EPO inducer and its effect in non-haematopoietic cells for therapeutic potential in ischemic disorders.

EXPERIMENTAL APPROACH

Mice kidney slices, primary hepatocytes, primary cardiomyocytes and C2C12 myoblasts were treated with EH-201. The effects of this treatment on EPO, Hb expression and mitochondrial biogenesis were analysed. In vivo, doxorubicin-induced cardiomyopathic mice were treated with EH-201. The mice were subjected to an endurance test, electrocardiography and echocardiography, and a histological examination of the isolated hearts was performed. EH-201 was also administered to cisplatin-induced nephropathic mice.

KEY RESULTS

In non-haematopoietic cells, EH-201 was potent at inducing EPO. EH-201 also stimulated mitochondrial biogenesis and enhanced the expression of Hb by a mechanism dependent on EPO-mediated signalling. In mechanistic studies, using EPO and EPO receptor-neutralizing antibodies, we confirmed that EH-201 enhances EPO-EPOR autocrine activity. EH-201 robustly increased the endurance performance activity of healthy and cardiomyopathic mice during hypoxic stress, enhanced myocardial mitochondrial biogenesis and Hb expression, and also improved cardiac function. EH-201 ameliorated anaemia and renal dysfunction in nephropathic mice.

CONCLUSIONS AND IMPLICATIONS

The enhancement and recovery of cellular functions through the stimulation of mitochondrial activity and Hb production in non-haematopoietic cells by an inducer of endogenous EPO has potential as a therapeutic strategy for ischaemic diseases.

Regenerative principles enrich cardiac rehabilitation practice

Cardiovascular morbidity imposes a high degree of disability and mortality, with limited therapeutic options available in end-stage disease. Integral to standard of care, cardiac rehabilitation aims on improving quality-of-life and prolonging survival. The recent advent of regenerative technologies paves the way for a transformative era in rehabilitation medicine whereby, beyond controlling risk factors and disease progression, the prospect of curative solutions is increasingly tangible. To date, the spectrum of clinical experience in cardiac regenerative medicine relies on stem cell-based therapies delivered to the diseased myocardium either acutely/subacutely, after a coronary event, or in the setting of chronic heart failure. Application of autologous/allogeneic stem cell platforms has established safety and feasibility, with encouraging signals of efficacy. Newer protocols aim to purify cell populations in an attempt to eliminate nonregenerative and enrich for regenerative cell types before use. Most advanced technologies have been developed to isolate resident cell populations directly from the heart or, alternatively, condition cells from noncardiac sources to attain a disease-targeted lineage-specified phenotype for optimized outcome. Because a multiplicity of cell-based technologies has undergone phase I/II evaluation, pivotal trials are currently underway in larger patient populations. Translation of regenerative principles into clinical practice will increasingly involve rehabilitation providers across the continuum of patient care. Regenerative rehabilitation is thus an emerging multidisciplinary field, full of opportunities and ready to be explored.

Cardiac stem cell therapy: review of the native cardiac progenitor cells and future direction

Various stem cell types have been tested for regenerating damaged myocardium after myocardial infarction. However, the results of clinical trials have not been consistent, with only some of the trials reporting small improvements in cardiac function. It seems that engraftment and survival of injected cells is limited and transplanted stem cells either do not differentiate into cardiac cells or differentiate into only limited number of cardiac cells. The exact mechanism(s) of cardiac functional improvement by cell therapy are unclear, but paracrine effect may play a central role. The resident cardiac progenitor cells identified within the adult myocardium have distinct advantages over other stem cell types for cardiac cell therapy, as they are likely precommitted to the cardiovascular fate. However, isolating and expanding these cells from cardiac biopsies is a challenge. More recently, direct reprogramming of fibroblasts into cardiomyocytes has given new hope for myocardial regeneration. Here we will review different stem cells used in cardiac cell therapy with a focus on the native cardiac progenitor cells and briefly outline future directions of cardiac cell therapy.

Efficacy and safety of bone marrow cell transplantation for chronic ischemic heart disease: a meta-analysis

Background

Although bone marrow-derived cells (BMCs) have shown great therapeutic potential in patients with chronic ischemic heart disease (CIHD), the exact efficacy and safety of BMCs therapy is still not completely defined.

Material/Methods

We searched PubMed, OVID, EMBASE, the Cochrane Library, and ClinicalTrials.gov and finally identified 20 qualified trials in this meta-analysis. Assessment of efficacy was based on left ventricular ejection fraction (LVEF), left ventricular end-systolic volume (LVESV), and left ventricular end-diastolic volume (LVEDV) improvement, by weighted mean difference (WMD) with 95% confidence intervals (CIs). Results of all-cause death, ventricular arrhythmia, recurrent myocardial infarction, and cerebrovascular accident were pooled to assess safety. Subgroup analysis was performed by stratifying RCTs into 2 subgroups of those with revascularization and without revascularization.

Results

BMC transplantation significantly improved LVEF in patients with revascularization (3.35%, 95% CI 0.72% to 5.97%, p=0.01; I²=85%) and without revascularization (3.05%, 95% CI 0.65% to 5.45%, p=0.01; I²=86%). In patients without revascularization, BMC transplantation was associated with significantly decreased LVESV (−11.75 ml, 95% CI −17.81 ml to −5.69 ml, p=0.0001; I²=81%), and LVEDV (−7.80 ml, 95% CI −15.31 ml to −0.29 ml, p=0.04; I²=39%). Subgroup analysis showed that the route of transplantation, baseline LVEF, and type of cells delivered could influence the efficacy of BMC transplantation.

Conclusions

Autologous transplantation of BMCs was safe and effective for patients who were candidates for revascularization with CABG/PCI and those who were not. However, large clinical trials and long-term follow-up are required to confirm these benefits.

Top 10 cardiovascular therapies and interventions for the next decade

Cardiovascular disease (CVD) has become the most-common cause of death worldwide. The Western lifestyle does not promote healthy living, and the consequences are most devastating when social inequalities are combined with economic factors and population growth. The expansion of poor nutritional habits, obesity, and associated conditions (such as diabetes mellitus, hypertension, physical inactivity, and advancing age) are major risk factors for developing CVD and are increasing in prevalence. Individuals in low-income and middle-income countries are undergoing a major shift in cardiovascular risk factors as they adopt Western lifestyles, a phenomenon that is hastened by industrialization, urbanization, and globalization. In this Perspectives article, I predict the 10 most-promising advances in cardiovascular therapies and interventions. Our improved understanding of CVD might help us, during the next decade, to achieve a transition from treating complex disease to promoting global cardiovascular health.

Bone marrow-derived cells for cardiovascular cell therapy: an optimized GMP method based on low-density gradient improves cell purity and function

Background

Cardiovascular cell therapy represents a promising field, with several approaches currently being tested. The advanced therapy medicinal product (ATMP) for the ongoing METHOD clinical study (“Bone marrow derived cell therapy in the stable phase of chronic ischemic heart disease”) consists of fresh mononuclear cells (MNC) isolated from autologous bone marrow (BM) through density gradient centrifugation on standard Ficoll-Paque. Cells are tested for safety (sterility, endotoxin), identity/potency (cell count, CD45/CD34/CD133, viability) and purity (contaminant granulocytes and platelets).

The aims of the present work were (1) to optimize the cell manufacturing process in order to reduce contaminants and (2) to implement additional assays in order to improve product characterization and evaluate product stability.

Methods

BM-MNC were isolated by density gradient centrifugation on Ficoll-Paque. The following process parameters were optimized throughout the study: gradient medium density; gradient centrifugation speed and duration; washing conditions.

Differential cell count was performed by an automated hematology cell analyzer. Immunophenotype and cell viability were determined by flow cytometry. Functional hematopoietic and mesenchymal precursors and cells with angiogenic potential were assessed by colony-forming assays, cell invasion capacity by a fluorimetric assay. Sterility was tested using an automated microbial detection system, endotoxin by a kinetic chromogenic Limulus amebocyte lysate test. T-test was used for statistical analysis.

Results

A new manufacturing method was set up, based on gradient centrifugation on low density Ficoll-Paque, followed by 2 washing steps, of which the second one at low speed. It led to significantly higher removal of contaminant granulocytes and platelets, improving product purity; the frequencies of CD34⁺ cells, CD133⁺ cells and functional hematopoietic and mesenchymal precursors were significantly increased.

The process was successfully validated according to Good Manufacturing Practices.

The resulting ATMP mainly consisted of viable MNC including CD34⁺ and CD133⁺ cell subsets (2.98% ± 1.90% and 0.83% ± 1.32%, respectively), CD184/CXCR4⁺ cells (34% ± 15%), CD34⁺/CD133⁺/CD309⁺ endothelial precursors (44 ± 21 in 10⁶ total cells), cells with invasion capacity, functional hematopoietic and mesenchymal precursors, cells with angiogenic potential; it was stable for 20 hours at 10°C.

Conclusions

The methodological optimization described here resulted in a significant improvement of ATMP quality, a crucial issue to clinical applications in cardiovascular cell therapy.

The role of tissue engineering and biomaterials in cardiac regenerative medicine

In recent years, the development of 3-dimensional engineered heart tissue (EHT) has made large strides forward because of advances in stem cell biology, materials science, prevascularization strategies, and nanotechnology. As a result, the role of tissue engineering in cardiac regenerative medicine has become multifaceted as new applications become feasible. Cardiac tissue engineering has long been established to have the potential to partially or fully restore cardiac function after cardiac injury. However, EHTs may also serve as surrogate human cardiac tissue for drug-related toxicity screening. Cardiotoxicity remains a major cause of drug withdrawal in the pharmaceutical industry. Unsafe drugs reach the market because preclinical evaluation is insufficient to weed out cardiotoxic drugs in all their forms. Bioengineering methods could provide functional and mature human myocardial tissues, ie, physiologically relevant platforms, for screening the cardiotoxic effects of pharmaceutical agents and facilitate the discovery of new therapeutic agents. Finally, advances in induced pluripotent stem cells have made patient-specific EHTs possible, which opens up the possibility of personalized medicine. Herein, we give an overview of the present state of the art in cardiac tissue engineering, the challenges to the field, and future perspectives.

Translating stem cell research to cardiac disease therapies: pitfalls and prospects for improvement

Over the past 2 decades, there have been numerous stem cell studies focused on cardiac diseases, ranging from proof-of-concept to phase 2 trials. This series of papers focuses on the legacy of these studies and the outlook for future treatment of cardiac diseases with stem cell therapies. The first section by Drs. Rosen and Myerburg is an independent review that analyzes the basic science and translational strategies supporting the rapid advance of stem cell technology to the clinic, the philosophies behind them, trial designs, and means for going forward that may impact favorably on progress. The second and third sections were collected as responses to the initial section of this review. The commentary by Drs. Francis and Cole discusses the review by Drs. Rosen and Myerburg and details how trial outcomes can be affected by noise, poor trial design (particularly the absence of blinding), and normal human tendencies toward optimism and denial. The final, independent paper by Dr. Marbán takes a different perspective concerning the potential for positive impact of stem cell research applied to heart disease and future prospects for its clinical application. (Compiled by the JACC editors).

Current Status and Perspectives in Stem Cell Therapy for Heart

For most patients, the prognosis of heart failure remains poor despite therapeutic advancement in recent decades. The option of cardiac transplantation is high risk and limited by a shortage of donors. Traditionally, the heart had been considered a terminally differentiated organ incapable of regeneration. However, numerous preclinical and clinical studies have been performed since the first report of cell therapy in heart failure using skeletal myoblasts in 2001. These investigations looked at the promising potential and use of several kinds of stem cells, which could some day dramatically alter the understanding of the regenerative capacity of the heart. To date, although there is no existing cardiac cell therapy that has been conclusively reported to be effective, stem cell-related cardiomyocyte regeneration strategies have become significant areas of research in modern cardiovascular medicine. In this review, we outline a variety of common cell sources, surface biomarkers of stem cells, and provide information related to cardiac cell therapy clinical trials.

KEY WORDS

Clinical trial; Stem cell.

Stem cell therapy for cardiac dysfunction

Following significant injury, the heart undergoes induced compensation and gradually deteriorates towards impending heart failure. Current therapy slows but does not halt the resultant adverse remodeling. Stem cell therapy, however, has the potential to regenerate or repair infarcted heart tissue and therefore is a promising therapeutic strategy undergoing intensive investigation. Due to the wide range of stem cells investigated, it is difficult to navigate this field. This review aims to summarize the main types of stem cells (both of cardiac and extra-cardiac origin) that possess promising therapeutic potential. Particular focus is placed on clinical trials supporting this therapeutic strategy.

Detailed analysis of bone marrow from patients with ischemic heart disease and left ventricular dysfunction: BM CD34, CD11b, and clonogenic capacity as biomarkers for clinical outcomes

RATIONALE

Bone marrow (BM) cell therapy for ischemic heart disease (IHD) has shown mixed results. Before the full potency of BM cell therapy can be realized, it is essential to understand the BM niche after acute myocardial infarction (AMI).

OBJECTIVE

To study the BM composition in patients with IHD and severe left ventricular (LV) dysfunction.

METHODS AND RESULTS

BM from 280 patients with IHD and LV dysfunction were analyzed for cell subsets by flow cytometry and colony assays. BM CD34(+) cell percentage was decreased 7 days after AMI (mean of 1.9% versus 2.3%-2.7% in other cohorts; P<0.05). BM-derived endothelial colonies were significantly decreased (P<0.05). Increased BM CD11b(+) cells associated with worse LV ejection fraction (LVEF) after AMI (P<0.05). Increased BM CD34(+) percentage associated with greater improvement in LVEF (+9.9% versus +2.3%; P=0.03, for patients with AMI and +6.6% versus -0.02%; P=0.021 for patients with chronic IHD). In addition, decreased BM CD34(+) percentage in patients with chronic IHD correlated with decrement in LVEF (-2.9% versus +0.7%; P=0.0355).

CONCLUSIONS

In this study, we show a heterogeneous mixture of BM cell subsets, decreased endothelial colony capacity, a CD34+ cell nadir 7 days after AMI, a negative correlation between CD11b percentage and postinfarct LVEF, and positive correlation of CD34 percentage with change in LVEF after cell therapy. These results serve as a possible basis for the small clinical improvement seen in autologous BM cell therapy trials and support selection of potent cell subsets and reversal of comorbid BM impairment.

CLINICAL TRIAL REGISTRATIONS URL

http://www.clinicaltrials.gov. Unique identifiers: NCT00684021, NCT00684060, and NCT00824005.

Effects of transendocardial CD34+ cell transplantation in patients with ischemic cardiomyopathy

BACKGROUND

We investigated the effects of transendocardial CD34(+) cell transplantation in patients with ischemic cardiomyopathy.

METHODS AND RESULTS

In a prospective crossover study, we enrolled 33 patients with ischemic cardiomyopathy with New York Heart Association class III and left ventricular ejection fraction <40%. In phase 1, patients were treated with medical therapy for 6 months. Thereafter, all patients underwent transendocardial CD34(+) cell transplantation. Peripheral blood CD34(+) cells were mobilized by granulocyte colony stimulating factor, collected via apheresis, and injected transendocardially in the areas of hibernating myocardium. Patients were followed up for 6 months after the procedure (phase 2). Two patients died during phase 1 and none during phase 2. The remaining 31 patients were 85% men, aged 57±6 years. In phase 1, we found no change in left ventricular ejection fraction (from 25.2±6.2% to 27.1±6.6%; P=0.23), N-terminal pro B-type natriuretic peptide (from 3322±3411 to 3672±5165 pg/mL; P=0.75) or 6-minute walk distance (from 373±68 to 411±116 m; P=0.17). In contrast, in phase 2 there was an improvement in left ventricular ejection fraction (from 27.1±6.6% to 34.9±10.9%; P=0.001), increase in 6-minute walk distance (from 411±116 to 496±113 m; P=0.001), and a decrease in N-terminal pro B-type natriuretic peptide (from 3672±5165 to 1488±1847 pg/mL; P=0.04). The average number of injected CD34(+) cells was 90.6±7.5×10(6). Higher doses of CD34(+) cells and a more diffuse distribution of transendocardial cell injections were associated with better clinical response.

CONCLUSIONS

Transendocardial CD34(+) cell transplantation may be associated with improved left ventricular function, decreased N-terminal pro B-type natriuretic peptide levels, and better exercise capacity in patients with ischemic cardiomyopathy. These effects seem to be particularly pronounced in patients receiving diffusely distributed cell injections and high-dose cell therapy.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01350310.