Pilot study to evaluate the safety and feasibility of intracoronary CD133(+) and CD133(-) CD34(+) cell therapy in patients with nonviable anterior myocardial infarction

The Use of Hematopoietic Stem Cells for Heart Failure: A Systematic Review

The purpose of this review is to summarize the current understanding of the therapeutic effect of stem cell-based therapies, including hematopoietic stem cells, for the treatment of ischemic heart damage. Following PRISMA guidelines, we conducted electronic searches in MEDLINE, and EMBASE. We screened 592 studies, and included RCTs, observational studies, and cohort studies that examined the effect of hematopoietic stem cell therapy in adult patients with heart failure. Studies that involved pediatric patients, mesenchymal stem cell therapy, and non-heart failure (HF) studies were excluded from our review. Out of the 592 studies, 7 studies met our inclusion criteria. Overall, administration of hematopoietic stem cells (via intracoronary or myocardial infarct) led to positive cardiac outcomes such as improvements in pathological left-ventricular remodeling, perfusion following acute myocardial infarction, and NYHA symptom class. Additionally, combined death, rehospitalization for heart failure, and infarction were significantly lower in patients treated with bone marrow-derived hematopoietic stem cells. Our review demonstrates that hematopoietic stem cell administration can lead to positive cardiac outcomes for HF patients. Future studies should aim to increase female representation and non-ischemic HF patients.

Combining stem cells in myocardial infarction: The road to superior repair?

Myocardial infarction irreversibly destroys millions of cardiomyocytes in the ventricle, making it the leading cause of heart failure worldwide. Over the past two decades, many progenitor and stem cell types were proposed as the ideal candidate to regenerate the heart after injury. The potential of stem cell therapy has been investigated thoroughly in animal and human studies, aiming at cardiac repair by true tissue replacement, by immune modulation, or by the secretion of paracrine factors that stimulate endogenous repair processes. Despite some successful results in animal models, the outcome from clinical trials remains overall disappointing, largely due to the limited stem cell survival and retention after transplantation. Extensive interest was developed regarding the combinational use of stem cells and various priming strategies to improve the efficacy of regenerative cell therapy. In this review, we provide a critical discussion of the different stem cell types investigated in preclinical and clinical studies in the field of cardiac repair. Moreover, we give an update on the potential of stem cell combinations as well as preconditioning and explore the future promises of these novel regenerative strategies.

Evaluation of the effectiveness of infusion of bone marrow derived cell in patients with heart failure: A network meta-analysis of randomized clinical trials and cohort studies

Background: The aim of this study was to investigate the effectiveness of bone marrow-derived cells (BMC) technology in patients with heart failure and compare it with alternative therapies, including drug therapy, cardiac resynchronization therapy pacemaker (CRT-P), cardiac resynchronization therapy defibrillator (CRT-D).

Methods: A systematic review study was conducted to identify all clinical studies published by 2017. Using keywords such as "Heart Failure, BMC, Drug Therapy, CRT-D, CRT-P" and combinations of the mentioned words, we searched electronic databases, including Scopus, Cochrane Library, and PubMed. The quality of the selected studies was assessed using the Cochrane Collaboration's tool and the Newcastle-Ottawa. The primary and secondary end-points were left ventricular ejection fraction (LVEF) (%), failure cases (Number), left ventricular end-systolic volume (LVES) (ml), and left ventricular end-diastolic volume (LVED) (ml). Random-effects network meta-analyses were used to conduct a systematic comparison. Statistical analysis was done using STATA.

Results: This network meta-analysis covered a total of 57 final studies and 6694 patients. The Comparative effectiveness of BMC versus CRT-D, Drug, and CRT-P methods indicated the statistically significant superiority of BMC over CRT-P (6.607, 95% CI: 2.92, 10.29) in LVEF index and overall CRT-P (-13.946, 95% CI: -18.59, -9.29) and drug therapy (-4.176, 95% CI: -8.02, -.33) in LVES index. In addition, in terms of LVED index, the BMC had statistically significant differences with CRT-P (-10.187, 95% CI: -18.85, -1.52). BMC was also dominant to all methods in failure cases as a final outcome and the difference was statistically significant i.e. BMC vs CRT-D: 0.529 (0.45, 0.62) and BMC vs Drug: 0.516 (0.44, 0.60). In none of the outcomes, the other methods were statistically more efficacious than BMC. The BMC method was superior or similar to the other methods in all outcomes.

Conclusion: The results of this study showed that the BMC method, in general, and especially in terms of failure cases index, had a higher level of clinical effectiveness. However, due to the lack of data asymmetry, insufficient data and head-to-head studies, BMC in this meta-analysis might be considered as an alternative to existing treatments for heart failure.

The State of Art of Regenerative Therapy in Cardiovascular Ischemic Disease: Biology, Signaling Pathways, and Epigenetics of Endothelial Progenitor Cells

Ischemic heart disease is currently a major cause of mortality and morbidity worldwide. Nevertheless, the actual therapeutic scenario does not target myocardial cell regeneration and consequently, the progression toward the late stage of chronic heart failure is common. Endothelial progenitor cells (EPCs) are bone marrow-derived stem cells that contribute to the homeostasis of the endothelial wall in acute and chronic ischemic disease. Calcium modulation and other molecular pathways (NOTCH, VEGFR, and CXCR4) contribute to EPC proliferation and differentiation. The present review provides a summary of EPC biology with a particular focus on the regulatory pathways of EPCs and describes promising applications for cardiovascular cell therapy.

Circulating Proangiogenic Cells and Proteins in Patients with Glioma and Acute Myocardial Infarction: Differences in Neovascularization between Neoplasia and Tissue Regeneration

Although extensive angiogenesis takes place in glial tumors, antiangiogenic therapies have remained without the expected success. In the peripheral circulation of glioma patients, increased numbers of endothelial precursor cells (EPCs) are present, potentially offering targets for antiangiogenic therapy. However, for an antiangiogenic therapy to be successful, the therapy should specifically target glioma-related EPC subsets and secreted factors only. Here, we compared the EPC subsets and plasma factors in the peripheral circulation of patients with gliomas to acute myocardial infarctions. We investigated the five most important EPC subsets and 21 angiogenesis-related plasma factors in peripheral blood samples of 29 patients with glioma, 14 patients with myocardial infarction, and 20 healthy people as controls, by FACS and Luminex assay. In GBM patients, all EPC subsets were elevated as compared to healthy subjects. In addition, HPC and KDR⁺ cell fractions were higher than in MI, while CD133⁺ and KDR⁺CD133⁺ cell fractions were lower. There were differences in relative EPC fractions between the groups: KDR⁺ cells were the largest fraction in GBM, while CD133⁺ cells were the largest fraction in MI. An increase in glioma malignancy grade coincided with an increase in the KDR⁺ fraction, while the CD133⁺ cell fraction decreased relatively. Most plasma angiogenic factors were higher in GBM than in MI patients. In both MI and GBM, the ratio of CD133⁺ HPCs correlated significantly with elevated levels of MMP9. In the GBM patients, MMP9 correlated strongly with levels of all HPCs. In conclusion, the data demonstrate that EPC traffic in patients with glioma, representing neoplasia, is different from that in myocardial infarction, representing tissue regeneration. Glioma patients may benefit from therapies aimed at lowering KDR⁺ cells and HPCs.

Regenerative Therapy for Cardiomyopathies

Despite substantial advances in the development of medical and interventional strategies in ischemic and non-ischemic heart diseases, cardiovascular diseases (CVDs) remain the leading cause of mortality and morbidity worldwide. Stem cell therapy for heart disease has gained traction over the past two decades and is an emerging option for the treatment of myocardial dysfunction. In this review, we summarize the current literature on different types of stem cells and their potential usage in ischemic and non-ischemic heart diseases. We emphasize the clinical utility of stem cells to improve myocardial structural and function, promote microvascular angiogenesis, and diminish scar size and major adverse cardiovascular events. We also discuss the therapeutic potential of microvesicles, such as exosomes, in the treatment of CVDs, which may open novel avenues for further clinical studies.

Adult Stem Cell Therapy for Cardiac Repair in Patients After Acute Myocardial Infarction Leading to Ischemic Heart Failure: An Overview of Evidence from the Recent Clinical Trials

Background:

Cardiovascular diseases (CVD) still represent the leading cause of mortality worldwide, despite the remarkable advances in interventional cardiology, cardiac surgery, and modern pharmacotherapy, particularly in the setting of acute myocardial infarction (AMI), chronic ischemic heart failure (HF), cardiomyopathy (CM), and the associated left ventricular (LV) dysfunction.

A significant loss of cardiomyocytes that underlies all of these conditions was previously considered irreversible. However, current evidence indicates that the human heart has some potential for repair, and over the past decade, many research studies have been exploring the use of stem cells (SCs) to facilitate restoration of myocardium. Consequently, the safety, feasibility, and effectiveness of SC therapy have been reported in many randomized clinical trials (RCTs), using different lineages of adult SCs. Nevertheless, the clinical benefits of SC therapy are not yet well established. In the near future, understanding of the complex interrelations between SCs, paracrine factors, genetic or epigenetic pre-dispositions, and myocardial microenvironment, in the context of an individual patient, will be crucial for translation of this knowledge into practical development of successful, long-term regenerative SC therapeutic applications, in a growing population of patients suffering from previous myocardial in-farction (MI) leading to chronic ischemic cardiomyopathy.

Conclusion:

This overview highlights the therapeutic potential of adult SCs in terms of their possible regenerative capacity, safety, and clinical outcomes, in patients with AMI, and/or subsequent HF (due to chronic ischemic cardiomyopathy). This review was based upon PubMed database search for trials on SC therapy, in patients with AMI and HF, and the main timeframe was set from 2006 to 2016.

Stem Cell Therapy: A New Therapeutic Option for Cardiovascular Diseases

Cardiovascular diseases are known as one of major causes of morbidity and mortality worldwide. Despite the many advancement in therapies are associated with cardiovascular diseases, it seems that finding of new therapeutic option is necessary. Cell therapy is one of attractive therapeutic platforms for treatment of a variety of diseases such as cardiovascular diseases. Among of various types of cell therapy, stem cell therapy has been emerged as an effective therapeutic approach in this area. Stem cells divided into multipotent stem cells and pluripotent stem cells. A large number studies indicated that utilization of each of them are associated with a variety of advantages and disadvantages. Multiple lines evidence indicated that stem cell therapy could be used as suitable therapeutic approach for treatment of cardiovascular diseases. Many clinical trials have been performed for assessing efficiency of stem cell therapies in human. However, stem cell therapy are associated with some challenges, but, it seems resolving of them could contribute to using of them as effective therapeutic approach for patients who suffering from cardiovascular diseases. In the current review, we summarized current therapeutic strategies based on stem cells for cardiovascular diseases. J. Cell. Biochem. 119: 95-104, 2018. © 2017 Wiley Periodicals, Inc.

Intramyocardial fate and effect of iron nanoparticles co-injected with MACS® purified stem cell products

BACKGROUND

Magnetic activated cell sorting (MACS^®) is routinely used to isolate stem cell subpopulations intended for the treatment of cardiovascular diseases. In strong contrast, studies examining the amount, effect and intramyocardial distribution of iron nanoparticles used for magnetic cell labelling are missing, although iron excess can cause functional disorders in the heart.

METHODS AND RESULTS

CD133⁺ haematopoietic and CD271⁺ mesenchymal stem cells were purified from bone marrow using automatically and manually MACS^® based systems. Flow cytometric measurements demonstrated a rapid loss of MACS^® MicroBeads from cells under culture conditions, while storage under hypothermic conditions decelerated their detachment. Moreover, an average loading of ∼11 fg iron/cell caused by magnetic labelling was determined in magnetic particle spectroscopy. Importantly, hemodynamic measurements as well as histological examinations using a myocardial ischemia/reperfusion mouse model showed no influence of MACS^® MicroBeads on cardiac regeneration, while the transplantation of stem cells caused a significant improvement. Furthermore, immunostainings demonstrated the clearance of co-injected iron nanoparticles from stem cells and the surrounding heart tissue within 48 h post transplantation.

CONCLUSIONS

Our results indicate that iron amounts typically co-injected with MACS^® purified stem cells do not harm cardiac functions and are cleared from heart tissue within a few hours. Therefore, we conclude that MACS^® MicroBeads exhibit a good compatibility in the cardiac environment.

Single cell biology beyond the era of antibodies: relevance, challenges, and promises in biomedical research

Research of the past two decades has proved the relevance of single cell biology in basic research and translational medicine. Successful detection and isolation of specific subsets is the key to understand their functional heterogeneity. Antibodies are conventionally used for this purpose, but their relevance in certain contexts is limited. In this review, we discuss some of these contexts, posing bottle neck for different fields of biology including biomedical research. With the advancement of chemistry, several methods have been introduced to overcome these problems. Even though microfluidics and microraft array are newer techniques exploited for single cell biology, fluorescence-activated cell sorting (FACS) remains the gold standard technique for isolation of cells for many biomedical applications, like stem cell therapy. Here, we present a comprehensive and comparative account of some of the probes that are useful in FACS. Further, we illustrate how these techniques could be applied in biomedical research. It is postulated that intracellular molecular markers like nucleostemin (GNL3), alkaline phosphatase (ALPL) and HIRA can be used for improving the outcome of cardiac as well as bone regeneration. Another field that could utilize intracellular markers is diagnostics, and we propose the use of specific peptide nucleic acid probes (PNPs) against certain miRNAs for cancer surgical margin prediction. The newer techniques for single cell biology, based on intracellular molecules, will immensely enhance the repertoire of possible markers for the isolation of cell types useful in biomedical research.

Regenerative capacity of autologous stem cell transplantation in elderly: a report of biomedical outcomes

The occurrence of chronic diseases such as neurological, metabolic and cardiovascular degenerative disorders increases with age. Cell therapy is an emerging approach to the treatment of these conditions. Of particular interest is the application of autologous stem cells because it eliminates post-transplantation immune rejection and there are less ethical concerns associated with their use. The regenerative capacity of stem cells harvested from elderly people is however controversial. In this review, we analyze if self-renewal potential, differentiation capability and expression of stemness genes in stem cells collected from elderly patients validate their application in clinical trials and examine the results.

GMP-conformant on-site manufacturing of a CD133+ stem cell product for cardiovascular regeneration

Background

CD133⁺ stem cells represent a promising subpopulation for innovative cell-based therapies in cardiovascular regeneration. Several clinical trials have shown remarkable beneficial effects following their intramyocardial transplantation. Yet, the purification of CD133⁺ stem cells is typically performed in centralized clean room facilities using semi-automatic manufacturing processes based on magnetic cell sorting (MACS®). However, this requires time-consuming and cost-intensive logistics.

Methods

CD133⁺ stem cells were purified from patient-derived sternal bone marrow using the recently developed automatic CliniMACS Prodigy® BM-133 System (Prodigy). The entire manufacturing process, as well as the subsequent quality control of the final cell product (CP), were realized on-site and in compliance with EU guidelines for Good Manufacturing Practice. The biological activity of automatically isolated CD133⁺ cells was evaluated and compared to manually isolated CD133⁺ cells via functional assays as well as immunofluorescence microscopy. In addition, the regenerative potential of purified stem cells was assessed 3 weeks after transplantation in immunodeficient mice which had been subjected to experimental myocardial infarction.

Results

We established for the first time an on-site manufacturing procedure for stem CPs intended for the treatment of ischemic heart diseases using an automatized system. On average, 0.88 × 10⁶ viable CD133⁺ cells with a mean log₁₀ depletion of 3.23 ± 0.19 of non-target cells were isolated. Furthermore, we demonstrated that these automatically isolated cells bear proliferation and differentiation capacities comparable to manually isolated cells in vitro. Moreover, the automatically generated CP shows equal cardiac regeneration potential in vivo.

Conclusions

Our results indicate that the Prodigy is a powerful system for automatic manufacturing of a CD133⁺ CP within few hours. Compared to conventional manufacturing processes, future clinical application of this system offers multiple benefits including stable CP quality and on-site purification under reduced clean room requirements. This will allow saving of time, reduced logistics and diminished costs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0467-0) contains supplementary material, which is available to authorized users.

Exosomes Mediate the Beneficial Effects of Exercise

It is known that moderate exercise can prevent the development of cardiovascular diseases, but the exact molecular mechanisms mediating cardioprotective effect of exercise remain unknown. Emerging evidence suggests that exercise has great impact on the biogenesis of exosomes, which have been found in both interstitial fluid and circulation, and play important roles in cellular communication. Exosomes carry functional molecules such as mRNAs, microRNA, and specific proteins, which can be used in the early diagnosis and targeted therapy of a variety of diseases. Our review focus on the current knowledge on exosome production, secretion, uptake and how exercise influence exosome content. We also highlight recent research development in exosome based approach for cardiac repair.

Stem cell transplantation dose in patients with acute myocardial infarction: A meta-analysis

OBJECTIVE

To evaluate whether stem cell transplantation improves global left ventricular ejection fraction (LVEF) in patients with acute myocardial infarction (AMI), and to determine the appropriate stem cell therapy dose as well as the effective period after stem cell transplantation for therapy.

METHODS

A systematic literature search included Pubmed, MEDLINE, China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM), and Cochrane Evidence-Based Medicine databases. The retrieval time limit ranged from January 1990 to June 2016. We also obtained full texts through manual retrieval, interlibrary loan and document delivery service, or by contacting the authors directly. According to our inclusion and exclusion criteria, data were extracted independently by two evaluators. In case of disagreement, a joint discussion occurred and a third researcher was utilized. Data were analyzed quantitatively using Revman 5.2. Summary results are presented as the weighted mean difference (WMD) with 95% confidence intervals (CIs). We collected individual trial data and conducted a meta-analysis to compare changes in global left ventricular ejection fraction (ΔLVEF) after stem cell therapy. In this study, four subgroups were based on stem cell dose (≤1 × 10⁷ cells, ≤1 × 10⁸ cells, ≤1 × 10⁹ cells, and ≤1 × 10¹⁰ cells) and three subgroups were based on follow-up time (<6 months, 6-12 months, and ≥12 months).

RESULTS

Thirty-four studies, which included 40 randomized controlled trials, were included in this meta-analysis, and 1927 patients were evaluated. Changes in global LVEF were significantly higher in the stem cell transplantation group than in the control group (95% CI: 2.35-4.26%, P < 0.01). We found no significant differences in ΔLVEF between the bone marrow stem cells (BMCs) group and control group when the dose of BMCs was ≤1 × 10⁷ [ΔLVEF 95% CI: 0.12-3.96%, P = 0.04]. The ΔLVEF in the BMCs groups was significantly higher than in the control groups when the dose of BMCs was ≤1 × 10⁸ [ΔLVEF 95% CI: 0.95-4.25%, P = 0.002] and ≤1 × 10⁹ [ΔLVEF 95% CI: 2.31-4.20%, P < 0.01]. In addition, when the dose of BMCs was between 10⁹ and 10¹⁰ cells, we did not observe any significant differences [ΔLVEF 95% CI: -0.99-11.82%, P = 0.10]. Our data suggest stem cell therapy improves cardiac function in AMI patients when treated with an appropriate dose of BMCs.

CONCLUSION

Stem cell transplantation after AMI could improve global LVEF. Stem cells may be effectively administered to patients with AMI doses between 10⁸ and 10⁹ cells.

Magnet-Bead Based MicroRNA Delivery System to Modify CD133+ Stem Cells

Aim. CD133⁺ stem cells bear huge potential for regenerative medicine. However, low retention in the injured tissue and massive cell death reduce beneficial effects. In order to address these issues, we intended to develop a nonviral system for appropriate cell engineering. Materials and Methods. Modification of human CD133⁺ stem cells with magnetic polyplexes carrying microRNA was studied in terms of efficiency, safety, and targeting potential. Results. High microRNA uptake rates (~80-90%) were achieved without affecting CD133⁺ stem cell properties. Modified cells can be magnetically guided. Conclusion. We developed a safe and efficient protocol for CD133⁺ stem cell modification. Our work may become a basis to improve stem cell therapeutical effects as well as their monitoring with magnetic resonance imaging.

Advances in stem cell therapy for cardiovascular disease (Review)

Cardiovascular disease constitutes the primary cause of mortality and morbidity worldwide, and represents a group of disorders associated with the loss of cardiac function. Despite considerable advances in the understanding of the pathologic mechanisms of the disease, the majority of the currently available therapies remain at best palliative, since the problem of cardiac tissue loss has not yet been addressed. Indeed, few therapeutic approaches offer direct tissue repair and regeneration, whereas the majority of treatment options aim to limit scar formation and adverse remodeling, while improving myocardial function. Of all the existing therapeutic approaches, the problem of cardiac tissue loss is addressed uniquely by heart transplantation. Nevertheless, alternative options, particularly stem cell therapy, has emerged as a novel and promising approach. This approach involves the transplantation of healthy and functional cells to promote the renewal of damaged cells and repair injured tissue. Bone marrow precursor cells were the first cell type used in clinical studies, and subsequently, preclinical and clinical investigations have been extended to the use of various populations of stem cells. This review addresses the present state of research as regards stem cell therapy for cardiovascular disease.

Autologous cell therapy with CD133+ bone marrow-derived stem cells for refractory Asherman's syndrome and endometrial atrophy: a pilot cohort study

STUDY QUESTION

Could cell therapy using autologous peripheral blood CD133+ bone marrow-derived stem cells (BMDSCs) offer a safe and efficient therapeutic approach for patients with refractory Asherman's syndrome (AS) and/or endometrial atrophy (EA) and a wish to conceive?

SUMMARY ANSWER

In the first 3 months, autologous cell therapy, using CD133+ BMDSCs in conjunction with hormonal replacement therapy, increased the volume and duration of menses as well as the thickness and angiogenesis processes of the endometrium while decreasing intrauterine adhesion scores.

WHAT IS KNOWN ALREADY

AS is characterized by the presence of intrauterine adhesions and EA prevents the endometrium from growing thicker than 5 mm, resulting in menstruation disorders and infertility. Many therapies have been attempted for these conditions, but none have proved effective.

STUDY DESIGN, SIZE, DURATION

This was a prospective, experimental, non-controlled study. There were 18 patients aged 30-45 years with refractory AS or EA were recruited, and 16 of these completed the study. Medical history, physical examination, endometrial thickness, intrauterine adhesion score and neoangiogenesis were assessed before and 3 and 6 months after cell therapy.

PARTICIPANTS/MATERIALS, SETTING, METHODS

After the initial hysteroscopic diagnosis, BMDSC mobilization was performed by granulocyte-CSF injection, then CD133+ cells were isolated through peripheral blood aphaeresis to obtain a mean of 124.39 million cells (range 42-236), which were immediately delivered into the spiral arterioles by catheterization. Subsequently, endometrial treatment after stem cell therapy was assessed in terms of restoration of menses, endometrial thickness (by vaginal ultrasound), adhesion score (by hysteroscopy), neoangiogenesis and ongoing pregnancy rate. The study was conducted at Hospital Clínico Universitario of Valencia and IVI Valencia (Spain).

MAIN RESULTS AND THE ROLE OF CHANCE

All 11 AS patients exhibited an improved uterine cavity 2 months after stem cell therapy. Endometrial thickness increased from an average of 4.3 mm (range 2.7-5) to 6.7 mm (range 3.1-12) ( ITALIC! P = 0.004). Similarly, four of the five EA patients experienced an improved endometrial cavity, and endometrial thickness increased from 4.2 mm (range 2.7-5) to 5.7 mm (range 5-12) ( ITALIC! P = 0.03). The beneficial effects of the cell therapy increased the mature vessel density and the duration and intensity of menses in the first 3 months, with a return to the initial levels 6 months after the treatment. Three patients became pregnant spontaneously, resulting in one baby boy born, one ongoing pregnancy and a miscarriage. Furthermore, seven pregnancies were obtained after fourteen embryo transfers, resulting in three biochemical pregnancies, one miscarriage, one ectopic pregnancy, one baby born and one ongoing pregnancy.

LIMITATIONS, REASONS FOR CAUTION

Limitations of this pilot study include the small sample size and the lack of control group.

WIDER IMPLICATIONS OF THE FINDINGS

This novel autologous cell therapy is a promising therapeutic option for patients with these incurable pathologies and a wish to conceive.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by the Spanish Ministry of Science and Innovation (SAF 2012-31017, Principal Investigator C.S.), Spanish Ministry of Health (EC11-299, Principal Investigator C.S.) and Regional Valencian Ministry of Education (PROMETEOII/2013/018, Principal Investigator C.S.). Four authors (X.S., I.C., A.P. and C.S.) are co-inventors of the patent resulting from this work (Application number: 62/013,121). S.C., C.A., F.R., J.F., J.P. and J.R. have no conflict of interest in relation to this work.

TRIAL REGISTRATION NUMBER

This study was registered with ClinicalTrials.gov (NCT02144987).

Myocardial infarction: stem cell transplantation for cardiac regeneration

It is estimated that by 2030, almost 23.6 million people will perish from cardiovascular disease, according to the WHO. The review discusses advances in stem cell therapy for myocardial infarction, including cell sources, methods of differentiation, expansion selection and their route of delivery. Skeletal muscle cells, hematopoietic cells and mesenchymal stem cells (MSCs) and embryonic stem cells (ESCs)-derived cardiomyocytes have advanced to the clinical stage, while induced pluripotent cells (iPSCs) are yet to be considered clinically. Delivery of cells to the sites of injury and their subsequent retention is a major issue. The development of supportive scaffold matrices to facilitate stem cell retention and differentiation are analyzed. The review outlines clinical translation of conjugate stem cell-based cellular therapeutics post-myocardial infarction.

Full GMP-compliant validation of bone marrow-derived human CD133(+) cells as advanced therapy medicinal product for refractory ischemic cardiomyopathy

According to the European Medicine Agency (EMA) regulatory frameworks, Advanced Therapy Medicinal Products (ATMP) represent a new category of drugs in which the active ingredient consists of cells, genes, or tissues. ATMP-CD133 has been widely investigated in controlled clinical trials for cardiovascular diseases, making CD133⁺ cells one of the most well characterized cell-derived drugs in this field. To ensure high quality and safety standards for clinical use, the manufacturing process must be accomplished in certified facilities following standard operative procedures (SOPs). In the present work, we report the fully compliant GMP-grade production of ATMP-CD133 which aims to address the treatment of chronic refractory ischemic heart failure. Starting from bone marrow (BM), ATMP-CD133 manufacturing output yielded a median of 6.66 × 10⁶ of CD133⁺ cells (range 2.85 × 10⁶–30.84 × 10⁶), with a viability ranged between 96,03% and 99,97% (median 99,87%) and a median purity of CD133⁺ cells of 90,60% (range 81,40%–96,20%). Based on these results we defined our final release criteria for ATMP-CD133: purity ≥ 70%, viability ≥ 80%, cellularity between 1 and 12 × 10⁶ cells, sterile, and endotoxin-free. The abovementioned criteria are currently applied in our Phase I clinical trial (RECARDIO Trial).

Bone Marrow Therapies for Chronic Heart Disease

Chronic heart failure is a leading cause of death. The demand for new therapies and the potential regenerative capacity of bone marrow-derived cells has led to numerous clinical trials. We critically discuss current knowledge of the biology and clinical application of bone marrow cells. It appears unlikely that bone marrow cells can develop into functional cardiomyocyte after infusion but may have favorable paracrine effects. Most, but not all, clinical trials report a modest short- but not long-term benefit of infusing bone marrow-derived cells. Effect size appears to correlate with stringency of study-design: the most stringent trials report the smallest effect-sizes. We conclude there may be short- but not substantial long-term benefit of infusing bone marrow-derived cells into persons with chronic heart failure and any benefit observed is unlikely to result from trans-differentiation of bone marrow-derived cells into functioning cardiomyocytes.

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.

Migration towards SDF-1 selects angiogenin-expressing bone marrow monocytes endowed with cardiac reparative activity in patients with previous myocardial infarction

Introduction

Chemokine-directed migration is crucial for homing of regenerative cells to the infarcted heart and correlates with outcomes of cell therapy trials. Hence, transplantation of chemokine-responsive bone marrow cells may be ideal for treatment of myocardial ischemia. To verify the therapeutic activity of bone marrow mononuclear cells (BM-MNCs) selected by in vitro migration towards the chemokine stromal cell-derived factor-1 (SDF-1) in a mouse model of myocardial infarction (MI), we used BM-MNCs from patients with previous large MI recruited in the TransACT-1&2 cell therapy trials.

Methods

Unfractioned BM-MNCs, SDF-1-responsive, and SDF-1-nonresponsive BM-MNCs isolated by patients recruited in the TransACT-1&2 cell therapy trials were tested in Matrigel assay to evaluate angiogenic potential. Secretome and antigenic profile were characterized by flow cytometry. Angiogenin expression was measured by RT-PCR. Cells groups were also intramyocardially injected in an in vivo model of MI (8-week-old immune deficient CD1-FOXN1^nu/nu mice). Echocardiography and hemodynamic measurements were performed before and at 14 days post-MI. Arterioles and capillaries density, infiltration of inflammatory cells, interstitial fibrosis, and cardiomyocyte proliferation and apoptosis were assessed by immunohistochemistry.

Results

In vitro migration enriched for monocytes, while CD34⁺ and CD133⁺ cells and T lymphocytes remained mainly confined in the non-migrated fraction. Unfractioned total BM-MNCs promoted angiogenesis on Matrigel more efficiently than migrated or non-migrated cells. In mice with induced MI, intramyocardial injection of unfractionated or migrated BM-MNCs was more effective in preserving cardiac contractility and pressure indexes than vehicle or non-migrated BM-MNCs. Moreover, unfractioned BM-MNCs enhanced neovascularization, whereas the migrated fraction was unique in reducing the infarct size and interstitial fibrosis. In vitro studies on isolated cardiomyocytes suggest participation of angiogenin, a secreted ribonuclease that inhibits protein translation under stress conditions, in promotion of cardiomyocyte survival by migrated BM-MNCs.

Conclusions

Transplantation of bone marrow cells helps post-MI healing through distinct actions on vascular cells and cardiomyocytes. In addition, the SDF-1-responsive fraction is enriched with angiogenin-expressing monocytes, which may improve cardiac recovery through activation of cardiomyocyte response to stress. Identification of factors linking migratory and therapeutic outcomes could help refine regenerative approaches.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0028-y) contains supplementary material, which is available to authorized users.

Sonic Hedgehog signaling regulates vascular differentiation and function in human CD34 positive cells: vasculogenic CD34(+) cells with Sonic Hedgehog

Identification of pivotal factors potentially present in the in situ environment and capable of influencing the function of CD34(+) cells, which can be used for autologous cell therapy, is of paramount interest. SHh is one of the morphogens essential for embryonic vascular development as well as postnatal neovascularization, and the activation of SHh signaling with angiogenic and vascular differentiation responses in CD34(+) cells by SHh treatment differed depending on the G-CSF treatment or the background disease. SHh enhanced the migration, proliferation, adhesion, and EPC colony forming capacities of G-CSF mobilized CD34(+) cells, increasing the vasculogenic/angiogenic potential for neovascularization. An increase in the differentiation potential of CD34(+) cells toward vascular lineages was demonstrated with SHh treatment involving TGFβ signaling pathway. The SHh-activated G-CSF mobilized CD34(+) cells directly contributed to vascular regeneration while non-activated CD34(+) cells showed a lower regenerative capacity in a mouse ischemic hindlimb model. SHh signaling regulates human CD34(+) cell fate and function, and may potentiate the therapeutic effect of G-CSF mobilized CD34(+) cells on ischemic diseases.

Utilization of stem cells to treat congenital heart disease: hype and hope

PURPOSE OF REVIEW

Surgical advances over the past few decades have transformed the clinical management of congenital heart disease, such as hypoplastic left heart syndrome. Congenital heart disease affects more than 1% of liveborn infants and accounts for more than 2.5 million affected children per year worldwide. The cost and availability of complex medical management for these children becomes bluntly realized when heart failure progresses and only palliative options remain. Cell-based cardiac regeneration has been the focus of intensive efforts in adult heart disease for more than a decade and now has promise for pediatrics.

RECENT FINDINGS

Innate cardiac regeneration in the pediatric setting is measurable and potentially modifiable in the early stages of development. Repurposing cell-based manufactured products to promote cardiac regeneration in congenital heart disease has demonstrated significant improvement in cases of dilated cardiomyopathy and structural heart disease in infants.

SUMMARY

A focus on preemptive cardiac regeneration in the pediatric setting may offer new insights into the timing of surgery, location of cell-based delivery, and type of cell-based regeneration that could further inform acquired cardiac disease applications. The concept of cell-based pediatric cardiac regenerative surgery could transform the management of congenital heart disease when cost-effective strategies produce a valuable adjunctive solution to improve outcomes of cardiac surgery.

Intracoronary injection of CD34-cells in chronic ischemic heart failure: 7 years follow-up of the DanCell study

OBJECTIVES

Seven years ago, the DanCell study was carried out to test the hypothesis of improvement in left ventricular ejection fraction (LVEF) following repeated intracoronary injections of autologous bone marrow-derived stem cells (BMSCs) in patients suffering from chronic ischemic heart failure. In this post hoc analysis, the long-term effect of therapy is assessed.

METHODS

32 patients [mean age 61 (SD ± 9), 81% males] with systolic dysfunction (LVEF 33 ± 9%) received two repeated intracoronary infusions (4 months apart) of autologous BMSCs (1,533 ± 765 × 10(6) BMSCs including 23 ± 11 × 10(6) CD34(+) cells and 14 ± 7 × 10(6) CD133(+) cells). Patients were followed for 7 years and deaths were recorded.

RESULTS

During follow-up, 10 patients died (31%). In univariate regression analysis, the total number of BMSCs, CD34(+) cell count and CD133(+) cell count did not significantly correlate with survival (hazard ratio: 0.999, 95% CI: 0.998-1.000, p = 0.24; hazard ratio: 0.94, 95% CI: 0.88-1.01, p = 0.10, and hazard ratio: 0.96, 95% CI: 0.87-1.07, p = 0.47, respectively). After adjustment for baseline variables in multivariate regression analysis, the CD34(+) cell count was significantly associated with survival (hazard ratio: 0.90, 95% CI: 0.82-1.00, p = 0.04).

CONCLUSIONS

Intracoronary injections of a high number of CD34(+) cells may have a beneficial effect on chronic ischemic heart failure in terms of long-term survival.

Laser-supported CD133+ cell therapy in patients with ischemic cardiomyopathy: initial results from a prospective phase I multicenter trial

Objectives

This study evaluates the safety, principal feasibility and restoration potential of laser-supported CD133+ intramyocardial cell transplantation in patients with ischemic cardiomyopathy.

Methods

Forty-two patients with severe ischemic cardiomyopathy (left ventricular ejection fraction (LVEF) >15% and <35%) were included in this prospective multicenter phase I trial. They underwent coronary artery bypass grafting (CABG) with subsequent transepicardial low-energy laser treatment and autologous CD133+ cell transplantation, and were followed up for 12 months. To evaluate segmental myocardial contractility as well as perfusion and to identify the areas of scar tissue, cardiac MRI was performed at 6 months and compared to the preoperative baseline. In addition, clinical assessment comprising of CCS scoring, blood and physical examination was performed at 3, 6 and 12 months, respectively.

Results

Intraoperative cell isolation resulted in a mean cell count of 9.7±1.2×10⁶. Laser treatment and subsequent CD133+ cell therapy were successfully and safely carried out in all patients and no procedure-related complications occurred. At 6 months, the LVEF was significantly increased (29.7±1.9% versus 24.6±1.5% with p = 0.004). In addition, freedom from angina was achieved, and quality of life significantly improved after therapy (p<0.0001). Interestingly, an extended area of transmural delayed enhancement (>3 myocardial segments) determined in the preoperative MRI was inversely correlated with a LVEF increase after laser-supported cell therapy (p = 0.024).

Conclusions

This multicenter trial demonstrates that laser-supported CD133+ cell transplantation is safe and feasible in patients with ischemic cardiomyopathy undergoing CABG, and in most cases, it appears to significantly improve the myocardial function. Importantly, our data show that the beneficial effect was significantly related to the extent of transmural delayed enhancement, suggesting that MRI-guided selection of patients is mandatory to ensure the effectiveness of the therapy.

Trial Registration:

EudraCT 2005-004051-35) Controlled-Trials.com ISRCTN49998633

Postischemic revascularization: from cellular and molecular mechanisms to clinical applications

After the onset of ischemia, cardiac or skeletal muscle undergoes a continuum of molecular, cellular, and extracellular responses that determine the function and the remodeling of the ischemic tissue. Hypoxia-related pathways, immunoinflammatory balance, circulating or local vascular progenitor cells, as well as changes in hemodynamical forces within vascular wall trigger all the processes regulating vascular homeostasis, including vasculogenesis, angiogenesis, arteriogenesis, and collateral growth, which act in concert to establish a functional vascular network in ischemic zones. In patients with ischemic diseases, most of the cellular (mainly those involving bone marrow-derived cells and local stem/progenitor cells) and molecular mechanisms involved in the activation of vessel growth and vascular remodeling are markedly impaired by the deleterious microenvironment characterized by fibrosis, inflammation, hypoperfusion, and inhibition of endogenous angiogenic and regenerative programs. Furthermore, cardiovascular risk factors, including diabetes, hypercholesterolemia, hypertension, diabetes, and aging, constitute a deleterious macroenvironment that participates to the abrogation of postischemic revascularization and tissue regeneration observed in these patient populations. Thus stimulation of vessel growth and/or remodeling has emerged as a new therapeutic option in patients with ischemic diseases. Many strategies of therapeutic revascularization, based on the administration of growth factors or stem/progenitor cells from diverse sources, have been proposed and are currently tested in patients with peripheral arterial disease or cardiac diseases. This review provides an overview from our current knowledge regarding molecular and cellular mechanisms involved in postischemic revascularization, as well as advances in the clinical application of such strategies of therapeutic revascularization.

Autologous bone marrow-derived stem cell therapy in heart disease: discrepancies and contradictions

BACKGROUND

Autologous bone marrow stem cell therapy is the greatest advance in the treatment of heart disease for a generation according to pioneering reports. In response to an unanswered letter regarding one of the largest and most promising trials, we attempted to summarise the findings from the most innovative and prolific laboratory.

METHOD AND RESULTS

Amongst 48 reports from the group, there appeared to be 5 actual clinical studies ("families" of reports). Duplicate or overlapping reports were common, with contradictory experimental design, recruitment and results. Readers cannot always tell whether a study is randomised versus not, open-controlled or blinded placebo-controlled, or lacking a control group. There were conflicts in recruitment dates, criteria, sample sizes, million-fold differences in cell counts, sex reclassification, fractional numbers of patients and conflation of competitors' studies with authors' own. Contradictory results were also common. These included arithmetical miscalculations, statistical errors, suppression of significant changes, exaggerated description of own findings, possible silent patient deletions, fractional numbers of coronary arteries, identical results with contradictory sample sizes, contradictory results with identical sample sizes, misrepresented survival graphs and a patient with a negative NYHA class. We tabulate over 200 discrepancies amongst the reports. The 5 family-flagship papers (Strauer 2002, STAR, IACT, ABCD, BALANCE) have had 2665 citations. Of these, 291 citations were to the pivotal STAR or IACT-JACC papers, but 97% of their eligible citing papers did not mention any discrepancies. Five meta-analyses or systematic reviews covered these studies, but none described any discrepancies and all resolved uncertainties by undisclosed methods, in mutually contradictory ways. Meta-analysts disagreed whether some studies were randomised or "accepter-versus-rejecter". Our experience of presenting the discrepancies to journals is that readers may remain unaware of such problems.

CONCLUSIONS

Modern reporting of clinical research can still be imperfect. The scientific literature absorbs such reports largely uncritically. Even meta-analyses seem to resolve contradictions haphazardly. Discrepancies communicated to journals are not guaranteed to reach the scientific community. Journals could consider prioritising systematic reporting of queries even if seemingly minor, and establishing a policy of "habeas data".

Cell therapy for heart failure: a comprehensive overview of experimental and clinical studies, current challenges, and future directions

Despite significant therapeutic advances, the prognosis of patients with heart failure (HF) remains poor, and current therapeutic approaches are palliative in the sense that they do not address the underlying problem of the loss of cardiac tissue. Stem cell-based therapies have the potential to fundamentally transform the treatment of HF by achieving what would have been unthinkable only a few years ago-myocardial regeneration. For the first time since cardiac transplantation, a therapy is being developed to eliminate the underlying cause of HF, not just to achieve damage control. Since the initial report of cell therapy (skeletal myoblasts) in HF in 1998, research has proceeded at lightning speed, and numerous preclinical and clinical studies have been performed that support the ability of various stem cell populations to improve cardiac function and reduce infarct size in both ischemic and nonischemic cardiomyopathy. Nevertheless, we are still at the dawn of this therapeutic revolution. Many important issues (eg, mechanism(s) of action of stem cells, long-term engraftment, optimal cell type(s), and dose, route, and frequency of cell administration) remain to be resolved, and no cell therapy has been conclusively shown to be effective. The purpose of this article is to critically review the large body of work performed with respect to the use of stem/progenitor cells in HF, both at the experimental and clinical levels, and to discuss current controversies, unresolved issues, challenges, and future directions. The review focuses specifically on chronic HF; other settings (eg, acute myocardial infarction, refractory angina) are not discussed.

Clinical trials of cardiac repair with adult bone marrow- derived cells

The past decade has witnessed a marked increase in the number of clinical trials of cardiac repair with adult bone marrow cells (BMCs). These trials included patients with acute myocardial infarction (MI) as well as chronic ischemic heart disease (IHD) and utilized different types of BMCs with variable numbers, routes of administration, and timings after MI. Given these differences in methods, the outcomes from these trials have been often disparate and controversial. However, analysis of pooled data suggests that BMC injection enhances left ventricular function, reduces infarct scar size, and improves remodeling in patients with acute MI as well as chronic IHD. BMC therapy also improves clinical outcomes during follow-up without any increase in adverse effects. Although the underlying mechanisms of heart repair are difficult to elucidate in human studies, valuable insights may be gleaned from subgroup analysis of key variables. This information may be utilized to design future randomized controlled trials to carefully determine the long-term safety and benefits of BMC therapy.

Stem cell transplantation in cardiovascular disease: an update

Despite the development of novel therapeutic strategies, cardiovascular diseases remain the main cause of morbidity and mortality worldwide. Many phase 1 and 2 clinical trials have reported the safety, feasibility and promising potential of stem cell transplantation, however, the optimal cell types, timing of infusion, cell dosage and routes of administration remain to be determined. This paper reviews the findings of various clinical studies and discusses the challenges facing the delivery of stem cell therapy in cardiovascular diseases.

Cord blood endothelial progenitor cells as therapeutic and imaging probes

Numerous studies demonstrated that neovascularization processes associated with severe tissue ischemia commonly found in conditions such as cardiovascular disorders and tumor growth occur via angiogenic and vasculogenic mechanisms. Over the past decade, it has been demonstrated that endothelial progenitor cells (EPCs) play a significant role in neo-angiogenic and neovasculogenic processes. Due to their ability to self-renew, circulate, home to the ischemic sites and differentiate into mature endothelial cells, EPCs derived from various sources hold enormous potential to be used as therapeutic agents in pro- or anti-angiogenic strategies for the treatment of ischemic and tumor conditions, respectively. However, the development of EPC-based therapies requires accompanying, noninvasive imaging protocol for in vivo tracking of transplanted cells. Hence, this review focuses on cord blood-derived EPCs and their role in neovascularization with emphasis on the potential use of EPCs as a therapeutic and imaging probe.

Adult bone marrow cell therapy improves survival and induces long-term improvement in cardiac parameters: a systematic review and meta-analysis

BACKGROUND

Despite rapid clinical translation and widespread enthusiasm, the therapeutic benefits of adult bone marrow cell (BMC) transplantation in patients with ischemic heart disease continue to remain controversial. A synthesis of the available data is critical to appreciate and underscore the true impact of this promising approach.

METHODS AND RESULTS

A total of 50 studies (enrolling 2625 patients) identified by database searches through January 2012 were included. Weighted mean differences for changes in left ventricular (LV) ejection fraction, infarct size, LV end-systolic volume, and LV end-diastolic volume were estimated with random-effects meta-analysis. Compared with control subjects, BMC-treated patients exhibited greater LV ejection fraction (3.96%; 95% confidence interval, 2.90-5.02; P<0.00001) and smaller infarct size (-4.03%, 95% confidence interval, -5.47 to -2.59; P<0.00001), LV end-systolic volume (-8.91 mL; 95% confidence interval, -11.57 to -6.25; P<0.00001), and LV end-diastolic volume (-5.23 mL; 95% confidence interval, -7.60 to -2.86; P<0.0001). These benefits were noted regardless of the study design (randomized controlled study versus cohort study) and the type of ischemic heart disease (acute myocardial infarction versus chronic ischemic heart disease) and persisted during long-term follow-up. Importantly, all-cause mortality, cardiac mortality, and the incidence of recurrent myocardial infarction and stent thrombosis were significantly lower in BMC-treated patients compared with control subjects.

CONCLUSIONS

Transplantation of adult BMCs improves LV function, infarct size, and remodeling in patients with ischemic heart disease compared with standard therapy, and these benefits persist during long-term follow-up. BMC transplantation also reduces the incidence of death, recurrent myocardial infarction, and stent thrombosis in patients with ischemic heart disease.

Development of serum-free quality and quantity control culture of colony-forming endothelial progenitor cell for vasculogenesis

Quantitative and qualitative impairment of endothelial progenitor cells (EPCs) limits the efficacy of autologous cell therapy in patients with cardiovascular diseases. Here, we developed a serum-free quality and quantity control culture system for colony-forming EPCs to enhance their regenerative potential. A culture with serum-free medium containing stem cell factor, thrombopoietin, vascular endothelial growth factor, interleukin-6, and Flt-3 ligand was determined as optimal quality and quantity culture (QQc) in terms of the most vasculogenic colony-forming EPC expansion, evaluated by the newly established EPC colony formation assay. The QQc of umbilical cord blood-CD133(+) cells for 7 days produced a 52.9-fold increase in total cell number and 3.28-fold frequency in definitive EPC colony development, resulting in a 203.9-fold increase in estimated total definitive EPC colony number in vitro. Pre- or post-QQc cells were intramyocardially transplanted into nude rats with myocardial infarction (MI). Echocardiographic and micromanometer-tipped conductance catheter examinations 28 days post-MI revealed significant preservation of left ventricular (LV) function in rats receiving pre- or post-QQc cells compared with those receiving phosphate-buffered saline. Assessments of global LV contractility indicated a dose-dependent effect of pre- or post-QQc cells and the superior potency of post-QQc cells over pre-QQc cells. Furthermore, immunohistochemistry showed more abundant formation of both human and rat endothelial cells and cardiomyocytes in the infarcted myocardium following transplantation of post-QQc cells compared with pre-QQc cells. Our optimal serum-free quality and quantity culture may enhance the therapeutic potential of EPCs in both quantitative and qualitative aspects for cardiovascular regeneration.

Bone marrow stem cell adherence into old anterior myocardial infarction: a scintigraphic study using Tl-201 and Tc-99m-HMPAO

AIM

The precise localization of bone marrow stem cells (SCs) into the necrotic tissue after intracoronary infusion (ICI) may be important for the therapeutic outcome. This study aims to examine the correlation between Tl-201 and Tc-99m-hexa-methyl-propylene-amine-oxime (HMPAO) images.

METHODS

Thirteen patients, aged 36-62 years, with an old, nonviable, anterior myocardial infarction (MI) and reduced myocardial contractility (LVEF <40%), underwent ICI of selected CD133(+) and CD133(neg)CD34(+) SCs. One hour after the ICI, SPECT imaging with Tc-99m-HMPAO was performed in all patients and the acquired images were compared with the images obtained during the initial imaging for demonstration of viability (myocardial perfusion imaging with pharmacologic stress and Tl-201). Furthermore, two fused bull's eye images of Tc-99m-HMPAO and Tl-201 rest reinjection were created in six patients and regions of interest were set on Tl-201 and Tc-99m-HMPAO bull's eye images.

RESULTS

The comparison of the two sets of images revealed an intense accumulation of the SCs in the infarcted area with absence of viability as assessed by Tl-201 reinjection images. In the subset of patients in whom fused bull's eye images were produced, the comparison demonstrated that the percentage of the infarcted area with SCs' adherence was 83.2 ± 17%.

CONCLUSIONS

Tl-201 images are complementary with the respective Tc-99m-HMPAO ones, revealing a precise localization of SCs in the infarcted area. Tc-99m-HMPAO labeling of SCs is a reliable method for cell monitoring after ICI in nonviable myocardium after an anterior MI.

The rise of cellular therapy

In 1938, the field of Transfusion Medicine began as the simpler entity - Blood Banking. It was a discipline that focused on collecting, processing, storing and distributing end stage blood cells, plasma and plasma fractions to patients. Over the years, the field progressed to include clinical patient services such as apheresis technology and with the development of stem cell transplantation as a standard of care, Cell Therapy. Now the discipline is also finding a niche in the area of Regenerative Medicine. The role played by Transfusion Medicine practitioners in Cell Therapy and Regenerative Medicine was predicated on many factors: (1) pre-existing, established protocols for therapeutic leukapheresis, (2) prior experience with mononuclear cell collection and processing, (3) long term familiarity with, and a clear understanding of, cGMP and cGLP guidelines, Federal regulations, and the voluntary standards established by various organizations, (4) close relationships with practitioners in clinical departments of medicine, pediatrics, oncology, surgery, and their subspecialty areas. While the initial Cell Therapy programs related primarily to hematopoietic stem cell transplantation, as Regenerative Medicine programs developed, transfusion specialists found it to be a related field that would also benefit from their input. Cell Therapy and Regenerative Medicine, now provide fertile soil for the seeds of Transfusion Medicine to grow. The once narrowly defined field of Blood Banking now encompasses involvement in major new Cellular Therapy/Regenerative Medicine research protocols related to treatment of patients with cancer as well as renal, hepatic and cardiac illnesses. This in turn provides opportunities for residents and fellows to consider robust careers in the field of Transfusion Medicine. In this manner we will move forward with one eye on the past and another on the promising future.

Mesenchymal stem cells or cardiac progenitors for cardiac repair? A comparative study

In the past, clinical trials transplanting bone marrow-derived mononuclear cells reported a limited improvement in cardiac function. Therefore, the search for stem cells leading to more successful stem cell therapies continues. Good candidates are the so-called cardiac stem cells (CSCs). To date, there is no clear evidence to show if these cells are intrinsic stem cells from the heart or mobilized cells from bone marrow. In this study we performed a comparative study between human mesenchymal stem cells (hMSCs), purified c-kit(+) CSCs, and cardiosphere-derived cells (CDCs). Our results showed that hMSCs can be discriminated from CSCs by their differentiation capacity towards adipocytes and osteocytes and the expression of CD140b. On the other hand, cardiac progenitors display a greater cardiomyogenic differentiation capacity. Despite a different isolation protocol, no distinction could be made between c-kit(+) CSCs and CDCs, indicating that they probably derive from the same precursor or even are the same cells.

Hypoxic/normoxic preconditioning increases endothelial differentiation potential of human bone marrow CD133+ cells

CD133+ cells are hemangioblasts that have capacity to generate into both hematopoietic and endothelial cells (ECs). Hypoxia/normoxia has shown to be the regulator of the balance between stemness and differentiation. In this study we performed Agilent's whole human genome oligo microarray analysis and examined the differentiation potential of the bone-marrow-derived CD133+ cells after hypoxic/normoxic preconditioning of CD133+ cells. Results showed that there was no significant increase in erythroid colony forming unit (CFU-E) and CFU-granulocyte, erythrocyte, monocyte, and megakaryocyte formation with cells treated under hypoxia/normoxia. However, a significant increment of EC forming unit at 24 h (143.2 +/- 8.0%) compared to 0 h (100 +/- 11.4%) was observed in CFU-EC analysis. Reverse transcription-polymerase chain reaction and immunostaining analysis showed that the differentiated cells diminished hematopoietic stem cell surface markers and acquired the gene markers and functional phenotype of ECs. The transcriptome profile revealed a cluster of 232 downregulated and 498 upregulated genes in cells treated for 24 h under hypoxia. The upregulated genes include angiogenic genes, angiogenic growth factor genes, angiogenic cytokine and chemokine genes, as well as angiogenic-positive regulatory genes, including FGFBP1, PDGFB, CCL15, CXCL12, CXCL6, IL-6, PTN, EREG, ERBB2, EDG5, FGF3, FHF2, GDF15, JUN, L1CAM, NRG1, NGFR, and PDGFB. On the other hand, angiogenesis inhibitors and related genes, including IL12A, MLLT7, STAB1, and TIMP2, are downregulated. Taken together, hypoxic/normoxic preconditioning may lead to the differentiation of CD133+ cells toward endothelial lineage, which may improve the current clinical trial studies.

Cell therapy for heart failure: the need for a new therapeutic strategy

Improvements in the treatment of ischemic heart disease have led to a significant growth in the numbers of patients with systolic heart failure secondary to myocardial injury. Current therapies fail to address the loss of contractile tissue due to myocardial injury. Cell therapy is singular in its promise of primarily treating this underlying issue through salvage of viable myocardium or generation of new contractile tissue. Multiple cell types have been used to target acute myocardial infarction, chronic ischemic heart disease and heart failure due to infarction. Bone marrow mononuclear cells have been used to increase myocardial salvage after acute infarction. Randomized trials of over 800 patients have demonstrated no safety issues, and meta-analyses have suggested an improvement in left ventricular function in treated patients with trends toward improvements in hard cardiac end points. Cell therapy for chronic ischemic heart disease with bone marrow angiogenic progenitors has shown similar safety and trends toward improvement in function. While these therapies have targeted patients with viable myocardium, myoblasts have been used to treat patients with left ventricular dysfunction secondary to transmural infarction. Cell types with cardiomyogenic potential, including induced pluripotent stem cells and cardiac progenitor cells, offer the promise of true myocardial regeneration. Future studies with these cells may open the door for true myocardial regeneration.

Dynamics of progenitor cells and ventricular assist device intervention

Experimental and clinical evidence suggests that a heterogeneous group of bone-marrow-derived circulating progenitor cells, with variations in phenotype and function, provide an endogenous repair mechanism, contributing to vascular healing and remodeling under physiological and pathological conditions, such as cancer, atherosclerosis, myocardial infarction, and end-stage heart failure. Implantation of ventricular assist devices (VADs) for circulatory support is indicated in selected patients with end-stage heart failure as a bridge to heart transplantation, however seldom; improvement of ventricular contractility has been well documented with prolonged cardiac unloading. The current review summarizes recent findings from in vitro and in vivo studies, focusing on the biological features and the possible role of progenitor cells in the transient myocardial recovery, occasionally seen after VAD implantation, and speculates on their clinical utilities for the treatment of the failing human heart.

Potential and clinical utility of stem cells in cardiovascular disease

The recent identification of bone marrow-derived adult stem cells and other types of stem cells that could improve heart function after transplantation have raised high expectations. The basic mechanisms have been studied mostly in murine models. However, these experiments revealed controversial results on transdifferentiation vs transfusion of adult stem cells vs paracrine effects of these cells, which is still being debated. Moreover, the reproducibility of these results in precisely translated large animal models is still less well investigated. Despite these weaknesses results of several clinical trials including several hundreds of patients with ischemic heart disease have been published. However, there are no solid data showing that any of these approaches can regenerate human myocardium. Even the effectiveness of cell therapy in these approaches is doubtful. In future we need in this important field of regenerative medicine: i) more experimental data in large animals that are closer to the anatomy and physiology of humans, including data on dose effects, comparison of different cell types and different delivery routes; ii) a better understanding of the molecular mechanisms involved in the fate of transplanted cells; iii) more intensive research on genuine regenerative medicine, applying genetic regulation and cell engineering.