Autotransplantation of Unmanipulated Bone Marrow into Scarred Myocardium is Safe and Enhances Cardiac Function in Humans

Stem cells and heart disease - Brake or accelerator?

After two decades of intensive research and attempts of clinical translation, stem cell based therapies for cardiac diseases are not getting closer to clinical success. This review tries to unravel the obstacles and focuses on underlying mechanisms as the target for regenerative therapies. At present, the principal outcome in clinical therapy does not reflect experimental evidence. It seems that the scientific obstacle is a lack of integration of knowledge from tissue repair and disease mechanisms. Recent insights from clinical trials delineate mechanisms of stem cell dysfunction and gene defects in repair mechanisms as cause of atherosclerosis and heart disease. These findings require a redirection of current practice of stem cell therapy and a reset using more detailed analysis of stem cell function interfering with disease mechanisms. To accelerate scientific development the authors suggest intensifying unified computational data analysis and shared data knowledge by using open-access data platforms.

Stem cell therapy for chronic heart failure

PURPOSE OF REVIEW

The aim of this review was to discuss recent advances in clinical aspects of stem cell therapy in heart failure with emphasis on patient selection, stem cell types and delivery methods.

RECENT FINDINGS

Several stem cell types have been considered for the treatment of patients with heart failure. In nonischemic heart failure, transplantation of CD34 cells improved myocardial performance, functional capacity and neurohumoral activation. In ischemic heart failure, cardiosphere-derived cells were shown to reduce myocardial scar burden with concomitant increase in viable tissue and regional systolic wall thickening. Both autologous and allogeneic mesenchymal stem cells were shown to be effective in improving heart function in patients with ischemic heart failure; this may represent an important step toward the development of a standardized stem cell product for widespread clinical use.

SUMMARY

Although trials of stem cell therapy in heart failure have shown promising results, the findings are not consistent. Given the wide spectrum of heart failure, it may be difficult to define a uniform stem cell therapy for all subsets of patients; instead, future stem cell therapeutic strategies should aim for a more personalized approach by establishing optimal stem cell type, dose and delivery method for an individual patient and disease state.

Magnetic manipulation of bacterial magnetic nanoparticle-loaded neurospheres

Specific targeting of cells to sites of tissue damage and delivery of high numbers of transplanted cells to lesion tissue in vivo are critical parameters for the success of cell-based therapies. Here, we report a promising in vitro model system for studying the homing of transplanted cells, which may eventually be applicable for targeted regeneration of damaged neurons in spinal cord injury. In this model system, neurospheres derived from human neuroblastoma SH-SY5Y cells labeled with bacterial magnetic nanoparticles were guided by a magnetic field and successfully accumulated near the focus site of the magnetic field. Our results demonstrate the effectiveness of using an in vitro model for testing bacterial magnetic nanoparticles to develop successful stem cell targeting strategies during fluid flow, which may ultimately be translated into in vivo targeted delivery of cells through circulation in various tissue-repair models.

Effect of autologous bone marrow cell transplantation combined with off-pump coronary artery bypass grafting on cardiac function in patients with chronic myocardial infarction

OBJECTIVES

This study aimed to investigate the feasibility and effects of intramuscular injections of autologous bone marrow cells (BMC) combined with off-pump coronary artery bypass grafts (OPCAB) on improving cardiac function in chronic myocardial infarction patients.

METHODS

Ninety patients with chronic myocardial infarction were prospectively enrolled and randomized to an OPCAB with saline or an OPCAB with BMC-treatment group. After finishing CABG, patients received injections of BMC or saline into the marginal area of the infarct. The primary endpoint was incidence of emergent adverse events within 6 months.

RESULTS

There were no differences between the control and BMC-treated groups in baseline ejection fractions (EF) or wall motion score indices (WMSI) in the affected segments. At the 6-month follow-up, the ejection fraction was significantly increased in the BMC-treated group compared to controls (47.58 ± 6.34 vs. 40.11 ± 7.42; p < 0.05), whereas the WMSI were significantly decreased (1.25 ± 0.32 vs. 1.54 ± 0.53; p < 0.05), with no occurrences of life-threatening arrhythmias or death. The addition of BMC injections to OPCAB treatment increased regional perfusion to the marginal infarct area.

CONCLUSION

These results demonstrate that BMC transplant is beneficial to the cardiac function with no adverse effects, and therefore a safe and feasible adjunct therapy providing beneficial effects in clinical practice.

Stem cell therapy and breast cancer treatment: review of stem cell research and potential therapeutic impact against cardiotoxicities due to breast cancer treatment

A new problem has emerged with the ever-increasing number of breast cancer survivors. While early screening and advances in treatment have allowed these patients to overcome their cancer, these treatments often have adverse cardiovascular side effects that can produce abnormal cardiovascular function. Chemotherapeutic and radiation therapy have both been linked to cardiotoxicity; these therapeutics can cause a loss of cardiac muscle and deterioration of vascular structure that can eventually lead to heart failure (HF). This cardiomyocyte toxicity can leave the breast cancer survivor with a probable diagnosis of dilated or restrictive cardiomyopathy (DCM or RCM). While current HF standard of care can alleviate symptoms, other than heart transplantation, there is no therapy that replaces cardiac myocytes that are killed during cancer therapies. There is a need to develop novel therapeutics that can either prevent or reverse the cardiac injury caused by cancer therapeutics. These new therapeutics should promote the regeneration of lost or deteriorating myocardium. Over the last several decades, the therapeutic potential of cell-based therapy has been investigated for HF patients. In this review, we discuss the progress of pre-clinical and clinical stem cell research for the diseased heart and discuss the possibility of utilizing these novel therapies to combat cardiotoxicity observed in breast cancer survivors.

Transplantation of bone marrow stem cells during cardiac surgery

BACKGROUND

This systematic review with meta-analysis sought to determine the efficacy and safety of intramyocardial transplantation of bone marrow stem cells during coronary artery bypass graft surgery on postoperative cardiac functional parameters such as left ventricular ejection fraction and left ventricular end-diastolic volume.

METHODS

Medline/PubMed, Embase, Elsevier, Sciences online database, and Google Scholar literature search were searched. The effect sizes measured were risk ratio for categorical variables and weighted mean difference with 95% confidence interval for calculating differences between mean values of baseline and follow-up cardiac functional parameters. A value of p < 0.1 for Q test, or I(2 )> 50%, indicated significant heterogeneity among studies. The literature search retrieved 2900 studies from screened databases, of which 2866 (98.6%) were excluded and 34 (619 patients) were included for scoping review. The final analysis included 9 studies (335 patients).

RESULTS

Pooled effects estimates of left ventricular ejection fraction and left ventricular end-diastolic volume showed that bone marrow stem cell transplantation had a weighted mean difference of 4.06 (95% confidence interval: 0.41-7.72; p = 0.02) and 7.06 (95% confidence interval: -8.58-22.7; p = 0.3), respectively.

CONCLUSIONS

Intramyocardial transplantation of bone marrow stem cells improves cardiac functional parameters, significantly increasing left ventricular ejection fraction with a nonsignificant reduction in left ventricular end-diastolic volume. Also, this therapeutic method has no life-threatening complications and was therefore found to be an effective and safe method.

Prospective, randomized, double-blinded trial of bone marrow cell transplantation combined with coronary surgery - perioperative safety study

OBJECTIVES

We present here a sub-study of our prospective, randomized, double-blinded trial of bone marrow mononuclear cell (BMMC) transplantation with coronary artery bypass surgery (CABG) (ClinicalTrials.gov Identifier: NCT00418418), evaluating our secondary end-point concerning hospital stay as well as perioperative morbidity. Injecting a substantial amount of biologically active cells into a diseased myocardium inspires concerns for safety, a concern overlooked in previous trials.

METHODS

We evaluated the immediate perioperative effects of intramyocardial injection of autologous BMMCs combined with CABG. In a randomized double-blinded manner, 39 patients received injections either of BMMCs (n = 20) or of vehicle medium (n = 19). The patients' haemodynamics, arterial blood gases, systemic vein oxygen level, blood glucose, acid-base balance, lactate, haemoglobin, body temperature and diuresis, as well as medications needed, were recorded in the operating theatre and in the intensive care unit (ICU) every 4 h throughout the first postoperative 24 h.

RESULTS

No dissimilarities in these parameters were detectable. In the ICU, the median need for adrenaline was 0.0086 µg/kg/min (first quartile 0.0000, third quartile 0.0204) for controls and 0.0090 µg/kg/min (0.0000, 0.0353) for BMMC patients (P = 0.757); for noradrenaline, 0.0586 µg/kg/min (0.0180, 0.0888) for controls and 0.0279 µg/kg/min (0.0145, 0.0780) for BMMC patients (P = 0.405). The median stay at the ICU was 2 days for both groups (1, 2 for controls; 1, 3 for BMMCs; P = 0.967). Within the first postoperative day, one control patient had an elevated level of creatine kinase-myocardial band fraction mass (CK-MBm) up to >100 µg/l; no BMMC patient showed elevated CK-MBm levels (P = 0.474).

CONCLUSIONS

Both intramyocardial BMMC and placebo injections appear safe during surgery and immediate ICU stay after treatment of heart failure.

Intramyocardial autologous bone marrow cell transplantation for ischemic heart disease: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This study was undertaken to evaluate the efficacy of intramyocardial bone marrow cell (BMC) transplant therapy for ischemic heart disease (IHD).

METHODS

The PubMed, Embase, and Cochrane Library databases through October 2013 were searched for randomized clinical trials (RCTs) of intramyocardial BMCs to treat IHD. The primary endpoint was change in left ventricular ejection fraction (LVEF). Secondary endpoints were changes in left ventricular end-systolic volume (LVESV) and left ventricular end-diastolic volume (LVEDV). Weighted mean differences for the changes were estimated with a random-effects model.

RESULTS

Eleven RCTs with 492 participants were included. Intramyocardial BMC transplantation increased LVEF (4.91%; 95% confidence interval [CI] 2.84%-6.99%; P<0.00001), reduced LVESV (10.66 mL; 95% CI, -18.92 mL to -2.41 mL; P=0.01), and showed a trend toward decreased LVEDV (-7.82 mL; 95% CI, -16.36 mL-0.71 mL; P=0.07). Patients suitable for revascularization with coronary artery bypass grafting had greater improvement in LVEF (7.60%; 95% CI, 4.74%-10.46%, P<0.00001) than those unsuitable for revascularization (3.76%; 95% CI, 2.20%-5.32%; P<0.00001). LVEDV reduction was also more significant in revascularizable IHD (-16.51 mL; 95% CI, -22.05 mL to -10.07 mL; P<0.00001) than non-revascularizable IHD (-0.89 mL; 95% CI, -8.44 mL-6.66 mL; P=0.82).

CONCLUSION

Intramyocardial BMC injection contributes to improvement in left ventricular dysfunction and reduction in left ventricular volume. Patients with revascularizable IHD may benefit more from this therapy.

Bone marrow cells for cardiac regeneration and repair: current status and issues

Extensive studies in experimental animal heart models and patients have shown the promise of bone marrow cell (BMC) transplantation as an alternative strategy to the conventional treatment modalities for cardiac repair. 'Stemness' of BMC to adopt cardiac phenotype, their potential as carriers of exogenous therapeutic genes and an inherent ability to express growth factors and cytokines to exert paracrine effects have been especially focused until recently. These findings suggest that locally delivered BMCs are capable of regenerating de novo myocardium. Others have shown that extensive neovascularization due to paracrine effects of the engrafted cells resulted in improved regional blood flow and reduced infarct size. Despite initial success, there are multiple fundamental issues that remain contentious. Indeed, resolving these issues will optimize future heart cell therapy protocols to achieve better prognosis in the clinical settings. This review is a concise, in-depth and critical appreciation of the role of BMCs in heart cell therapy and builds a conceptual framework to elaborate their significance as a possible source of donor cells. Moreover, it discusses the current status of BMC transplantation as a clinical modality and the relevant issues confronting this approach in light of the published data with clinical relevance.

Tracking of stem cells in vivo for cardiovascular applications

In the past ten years, the concept of injecting stem and progenitor cells to assist with rebuilding damaged blood vessels and myocardial tissue after injury in the heart and peripheral vasculature has moved from bench to bedside. Non-invasive imaging can not only provide a means to assess cardiac repair and, thereby, cellular therapy efficacy but also a means to confirm cell delivery and engraftment after administration. In this first of a two-part review, we will review the different types of cellular labeling techniques and the application of these techniques in cardiovascular magnetic resonance and ultrasound. In addition, we provide a synopsis of the cardiac cellular clinical trials that have been performed to-date.

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.

The Reverse Remodeling Effect of Mesenchymal Stem Cells is Independent from the Site of Epimyocardial Cell Transplantation

Objective

The transplantation of mesenchymal stem cells (MSCs) represents a promising approach for treating the ischemic and the nonischemic diseased heart. The positive effects of transplanting these cells could be shown, but the exact mechanisms remain unknown. We evaluated whether the injection site affects the improvement in left ventricular (LV) ejection fraction (EF) and angiogenesis in doxorubicin (Dox)–induced failing hearts.

Methods

Heart failure was induced in New Zealand white rabbits by doxorubicin treatment, followed by right ventricular MSC transplantation (RV-MSC, n = 6), LV MSC transplantation (LV-MSC, n = 6), sham treatment (sham group, n = 6), or no therapy (Dox group, n = 5). Healthy rabbits were used as control group (n = 8). Cells were isolated after bone marrow aspiration and transplanted locally into the ventricular myocardium. After 4 weeks, cardiac function and capillary density (CD31 staining) were measured.

Results

The transplantation of MSCs increased the EF significantly (LV-MSC, 39.0% ± 1.4%, and RV-MSC, 39.2% ± 2.6%, vs sham group, 29.8% ± 3.7%; P < 0.001), without significance between the MSC groups ( P = 0.858). Neither the evidence of a transdifferentiation nor any signs of cell engraftment of transplanted cells could be found. The capillary density (capillaries/high-power field) increased in both MSC groups compared with the sham group (LV-MSC by 8.3% ± 3.4%; and RV-MSC, 8.1% ± 2.2%; P < 0.05), without significance between the two MSC groups ( P = 0.927).

Conclusions

Injection of autologous MSCs in doxorubicin-induced cardiomyopathic rabbit hearts improves EF and enhances angiogenesis. Despite local application, we observed global effects on heart function and capillary density without significant difference between right and LV injection. The paracrine mechanism might be one possible explanation for these findings.

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.

Distribution of cardiac stem cells in the human heart

Introduction. The existence of human cardiac stem cells (hCSC) and their regenerative capacity are not fully defined. The aim of this study was to identify and analyse the distribution of hCSCs by flow cytometry (FCM). Methods. Tissue samples from the left ventricle (LV) and the appendages of the right atrium (RA) and left atrium (LA) were taken during cardiac surgery. Mononuclear cells (MNCs) were isolated, labelled for the stem-cell-marker c-kit and hematopoietic-lineage markers and analysed by FCM. Results. HCSCs could be isolated from the RA, LA, and LV without significant quantitative difference between both atria (A) (RA 4.80 ± 1.76% versus LA 4.99 ± 1.69% of isolated MNCs, P = 0.922). The number of hCSCs was significantly higher in both atria compared to the left ventricle (A 4.90 ± 1.29% versus LV 0.62 ± 0.14% of isolated MNCs, P = 0.035). Conclusion. The atria contain a higher concentration of hCSC than the left ventricle. HCSCs located in the atria could serve as an endogenous source for heart regeneration.

A double-blind, randomized, controlled, multicenter study to assess the safety and cardiovascular effects of skeletal myoblast implantation by catheter delivery in patients with chronic heart failure after myocardial infarction

BACKGROUND

We sought to determine the safety and preliminary efficacy of transcatheter intramyocardial administration of myoblasts in patients with heart failure (HF).

METHODS

MARVEL is a randomized placebo-controlled trial of image-guided, catheter-based intramyocardial injection of placebo or myoblasts (400 or 800 million) in patients with class II to IV HF and ejection fraction <35%. Primary end points were frequency of serious adverse events (safety) and changes in 6-minute walk test and Minnesota Living With HF score (efficacy). Of 330 patients intended for enrollment, 23 were randomized (MARVEL-1) before stopping the study for financial reasons.

RESULTS

At 6 months, similar numbers of events occurred in each group: 8 (placebo), 7 (low dose), and 8 (high dose), without deaths. Ventricular tachycardia responsive to amiodarone was more frequent in myoblast-treated patients: 1 (placebo), 3 (low dose), and 4 (high dose). A trend toward improvement in functional capacity was noted in myoblast-treated groups (Δ6-minute walk test of -3.6 vs +95.6 vs +85.5 m [placebo vs low dose vs high dose; P = .50]) without significant changes in Minnesota Living With HF scores.

CONCLUSIONS

In HF patients with chronic postinfarction cardiomyopathy, transcatheter administration of myoblasts in doses of 400 to 800 million cells is feasible and may lead to important clinical benefits. Ventricular tachycardia may be provoked by myoblast injection but appears to be a transient and treatable problem. A large-scale outcome trial of myoblast administration in HF patients with postinfarction cardiomyopathy is feasible and warranted.

Tracking stem cells for cardiovascular applications in vivo: focus on imaging techniques

Despite rapid translation of stem cell therapy into clinical practice, the treatment of cardiovascular disease using embryonic stem cells, adult stem and progenitor cells or induced pluripotent stem cells has not yielded satisfactory results to date. Noninvasive stem cell imaging techniques could provide greater insight into not only the therapeutic benefit, but also the fundamental mechanisms underlying stem cell fate, migration, survival and engraftment in vivo. This information could also assist in the appropriate choice of stem cell type(s), delivery routes and dosing regimes in clinical cardiovascular stem cell trials. Multiple imaging modalities, such as MRI, PET, SPECT and CT, have emerged, offering the ability to localize, monitor and track stem cells in vivo. This article discusses stem cell labeling approaches and highlights the latest cardiac stem cell imaging techniques that may help clinicians, research scientists or other healthcare professionals select the best cellular therapeutics for cardiovascular disease management.

Association of polymorphisms of zinc metalloproteinases with clinical response to stem cell therapy

AIM

The purpose of this study was to assess the associations of polymorphisms in two metalloproteinase genes-metalloproteinase-2 (MMP-2) and angiotensin converting enzyme (ACE)-with clinical response to autologous transplantation of mononuclear bone marrow cells (MBMC) in patients with acute myocardial infarction.

METHODS

The double centre study included 48 patients with a first acute myocardial infarction treated with primary coronary angioplasty, stent implantation and transplantation of MBMC. According to the changes in perfusion defect size, left ventricle ejection fraction, end-systolic volume and peak systolic velocity of the infracted wall (dSaMI) after cell therapy, the patients were retrospectively divided into group A (responders) and group B (non-responders). Genomic DNA was isolated from peripheral leukocytes by a standard technique using proteinase K. Three MMP-2 promoter (-1575G/A, -1306C/T and -790T/G) as well as I/D ACE gene polymorphisms were detected by PCR methods with restriction analyses (when necessary) according to standard protocols.

RESULTS

Of the 48 patients who received MBMC transplantation, 17 responded to the therapy. There were no significant differences in the prevalence of matrix metalloproteinase-2 triple genotype GGCCTT between responder/non-responder groups (71% versus 61%, p=0.375). Similarly, no differences in either genotype distribution or allelic frequencies of I/D ACE polymorphism between responders and non-responders to the cell therapy were observed (p=0.933). Compared to patients with ACE genotype ID or DD, the patients with ACE II genotype significantly improved in regional systolic LV function of the infarcted wall after implantations of MBMC (dSaMI - 0.4 versus 1.4 cm/s, p=0.037).

CONCLUSION

In our study, the ACE genotype II was associated with improvement of regional systolic LV function of the infarcted wall after implantations of MBMC. The detected polymorphism in matrix metalloproteinase-2 gene was not associated with clinical response to cell therapy.

Stem cell therapy for heart diseases

BACKGROUND

Cardiovascular disease is the leading cause of morbidity and mortality worldwide. Despite the advances in medical and catheter-based therapy for acute myocardial infarction the 1-year mortality remains as high as 13% and the 5-year prognosis for patients with heart failure remains as high as 50%. Left ventricular systolic dysfunction, a major determinant of prognosis, is associated with significant loss of cardiomyocytes which was previously thought to be irreversible as the heart was considered a post-mitotic organ.

SOURCES OF DATA

Review of literature published in peer reviewed journals and ClinicalTrials.Gov website.

AREAS OF AGREEMENT

There is now growing evidence that the human heart is capable of undergoing repair and in recent years there has been an increase in basic and clinical research with the aim of harnessing the regenerative properties of stem cells in order to facilitate restoration of myocardial function.

AREAS OF CONTROVERSY

The mechanisms of action of cell therapy with regards to cardiac repair remain unsatisfactorily understood and the magnitude of benefit demonstrated in animal models is yet to be fully translated in humans.

GROWING POINTS

The number of clinical trials continues to increase and include treating patients with acute myocardial infarction and chronic heart failure secondary to ischaemic heart disease or dilated cardiomyopathy.

AREAS TIMELY FOR DEVELOPING RESEARCH

The future of this field of research will require closer collaboration between scientists and clinicians to understand how cell therapy works and to define the ideal cell type and method of delivery to be able to derive maximum benefit.

Transcoronary bone marrow-derived progenitor cells in a child with myocardial infarction: first pediatric experience

BACKGROUND

Recent advances in stem cell therapy to restore cardiac function have great promise for patients with congestive heart failure after myocardial infarction in an adult population.

OBJECTIVE

We examined the benefits of bone marrow-derived progenitor cells treatment modality for the pediatric patient.

METHODS AND RESULTS

We present our first case of transcoronary autologous stem cell transplantation in a 9-year-old girl with refractory congestive heart failure secondary to myocardial infarction 1 year after transcatheter revascularization. The child received daily injections of granulocyte colony-stimulating factor for 3 days prior to the bone marrow aspiration. The bone marrow cells were isolated to constitute CD133+/CD34+ more than 90% of the total number. Subsequently, the progenitor cell suspension was injected via a transcoronary catheter without any complication. Three months after stem cell therapy, her cardiac function, assessed by both cardiac magnetic resonance and echocardiogram, has been improved with the left ventricular ejection fraction at 47% compared to the baseline of 30%.

CONCLUSION

This is the first reported pediatric case of successful transcoronary injection of bone marrow-derived progenitor cells for end-stage heart disease. The procedure is considered safe and feasible for the pediatric population.

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.

Clinical application of stem cells in the cardiovascular system

Regenerative medicine encompasses "tissue engineering" - the in vitro fabrication of tissues and/or organs using scaffold material and viable cells - and "cell therapy" - the transplantation or manipulation of cells in diseased tissue in vivo. In the cardiovascular system, tissue engineering strategies are being pursued for the development of viable replacement blood vessels, heart valves, patch material, cardiac pacemakers and contractile myocardium. Anecdotal clinical applications of such vessels, valves and patches have been described, but information on systematic studies of the performance of such implants is not available, yet. Cell therapy for cardiovascular regeneration, however, has been performed in large series of patients, and numerous clinical studies have produced sometimes conflicting results. The purpose of this chapter is to summarize the clinical experience with cell therapy for diseases of the cardiovascular system, and to analyse possible factors that may influence its outcome.

Angiomyogenesis for myocardial repair

The conventional therapeutic modalities for myocardial infarction have limited success in preventing the progression of left ventricular remodeling and congestive heart failure. The heart cell therapy and therapeutic angiogenesis are two promising strategies for the treatment of ischemic heart disease. After extensive assessment of safety and effectiveness in vitro and in experimental animal studies, both of these approaches have accomplished the stage of clinical utility, albeit with limited success due to the inherent limitations and problems of each approach. Neomyogenesis without restoration of regional blood flow may be less meaningful. A combined stem-cell and gene-therapy approach of angiomyogenesis is expected to yield better results as compared with either of the approaches as a monotherapy. The combined therapy approach will help to restore the mechanical contractile function of the weakened myocardium and alleviate ischemic condition by restoration of regional blood flow. In providing an overview of both stem cell therapy and gene therapy, this article is an in-depth and critical appreciation of combined cell and gene therapy approach for myocardial repair.

Combined treatment of intrapancreatic autologous bone marrow stem cells and hyperbaric oxygen in type 2 diabetes mellitus

The objective of this study was to determine whether the combination therapy of intrapancreatic autologous stem cell infusion (ASC) and hyperbaric oxygen treatment (HBO) before and after ASC can improve islet function and metabolic control in patients with type 2 diabetes mellitus (T2DM). This prospective phase 1 study enrolled 25 patients with T2DM who received a combination therapy of intrapancreatic ASC and peri-infusion HBO between March 2004 and October 2006 at Stem Cells Argentina Medical Center Buenos Aires, Argentina. Clinical variables (body mass index, oral hypoglycemic drugs, insulin requirement) and metabolic variables (fasting plasma glucose, C-peptide, HbA1c, and calculation of C-peptide/glucose ratio) were assessed over quartile periods starting at baseline and up to 1 year follow-up after intervention. Means were calculated in each quartile period and compared to baseline. Seventeen male and eight female patients were enrolled. Baseline variables expressed as means +/- SEs were: age 55 +/- 2.14 years, diabetes duration 13.2 +/- 1.62 years, insulin dose 34.8 +/- 2.96 U/day, and BMI 27.11 +/- 0.51. All metabolic variables showed significant improvement when comparing baseline to 12 months follow-up, respectively: fasting glucose 205.6 +/- 5.9 versus 105.2 +/- 14.2 mg/dl, HbAlc 8.8 +/- 0.2 versus 6.0 +/- 0.4%, fasting C-peptide 1.5 +/- 0.2 versus 3.3 +/- 0.3 ng/ml, C-peptide/glucose ratio 0.7 +/- 0.2 versus 3.5 +/- 0.3, and insulin requirements 34.8 +/- 2.9 versus 2.5 +/- 6.7 U/day. BMI remained constant over the 1-year follow-up. Combined therapy of intrapancreatic ASC infusion and HBO can improve metabolic control and reduce insulin requirements in patients with T2DM. Further randomized controlled clinical trials will be required to confirm these findings.

Cell-based therapy for heart disease: a clinically oriented perspective

Over the past decade, cell therapy has emerged as a potential new treatment of a variety of cardiac diseases, including acute myocardial infarction, refractory angina, and chronic heart failure. A myriad of cell types have been tested experimentally, each of them being usually credited by its advocates of a high "regeneration" potential. This has led to a flurry of clinical trials entailing the use of skeletal myoblasts or bone marrow-derived cells either unfractionated or enriched in progenitor subpopulations. As often in medicine, the hype generated by the early uncontrolled and small-sized studies has been dampened by the marginally successful outcomes of the subsequent, more rigorously conducted randomized trials. Although they may have failed to achieve their primary end points, these trials have been positive in the sense that they have allowed to identify some key issues and it is reasonable to speculate that if these issues can now be addressed by appropriately focused benchwork, the outcomes of the second generation of cell-transplantation studies would likely be upgraded. It, thus, appears that not "one cell fits all" but that the selection of the cell type should be tailored to the primary clinical indication. On the one hand, it does not make sense to develop an "ideal" cell in a culture dish, if we remain unable to deliver it appropriately and to keep it alive, at least for a while, which requires to improve on the delivery techniques and to provide cells along with the vascular and extracellular matrix type of support necessary for their survival and patterning. On the other hand, the persisting mechanistic uncertainties about cell therapy should not preclude continuing clinical trials, which often provide the unique opportunity of identifying issues missed by our suboptimal preclinical models. Finally, regardless of whether cells are expected to act paracrinally or by physically replacing lost cardiomyocytes and, thus, effecting a true myocardial regeneration, safety remains a primary concern. It is, thus, important that clinical development programs be shaped in a way that allows the final cell-therapy product to be manufactured from fully traceable materials, phenotypically well characterized, consistent, scalable, sterile, and genetically stable as these characteristics are those that will be required by the ultimate gatekeeper, i.e., the regulator, and are thus unbypassable prerequisites for an effective and streamlined leap from bench to bedside.

Two-Dimensional Speckle Tracking Strain Analysis for Efficacy Assessment of Myocardial Cell Therapy

The subtle effects of transplanted bone marrow cells (BMC) on regional myocardial behavior in patients with ischemic heart disease are difficult to assess. Novel echocardiographic techniques can quantify regional myocardial deformation (strain) and distinguish between passive and active wall motion. We hypothesized that this technique may help delineate cell therapy-induced changes in regional LV contractility that escape clinical routine studies. Twelve patients with coronary artery disease and impaired LV function (LVEF &<35%) underwent CABG surgery plus intramyocardial injection of autologous bone marrow mononuclear cells. Between two and five predefined segments of ischemic myocardium per patient received BMCs, and untreated ischemic segments served as internal controls. Segmental echocardiographic analysis of peak systolic strain by speckle tracking was performed before and 1 year after surgery and compared with standard wall motion analysis. Two patients died during the follow-up period. In the remaining 10 patients, mean LVEF increased from 24.5 ± 10% to 32.1 ± 11% ( p = 0.02). A moderate improvement of systolic function was noted in ischemic control segments by both wall motion score (WMS) and 2D strain echocardiography (2DSE). In BMC-treated segments, WMS improved slightly, but the data failed to reach statistical significance. As assessed by 2DSE, however, systolic function of BMC-treated segments improved by nearly 100%. 2DSE proved to detect BMC-induced change with 30-fold higher sensitivity than WMS, and the Receiver Operating Characteristic curve (ROC) confirmed the diagnostic precision of 2DSE (area-under-the-ROC = 0.87). We conclude that echocardiographic speckle tracking two-dimensional strain analysis can detect cell therapy-induced changes in regional contractile function that may escape detection by standard wall motion assessment. Thus, 2DSE may be a useful tool for the further development of clinical cardiac cell therapy.

Autologous bone marrow-derived stem cells for ischemic heart failure: REGENERATE-IHD trial

The field of autologous stem/progenitor cell transplantation for cardiovascular diseases has moved rapidly from basic science research to clinical trials. To date, only a handful of pilot studies have reported the use of this novel strategy for heart failure patients. Most of these studies have demonstrated encouraging safety and efficacy data. However, this will need to be validated in large, randomized trials. Here, we introduce the ongoing REGENERATE-IHD trial, which is the largest randomized, placebo-controlled trial in the UK investigating the use of granulocyte-colony stimulating factor and autologous bone marrow-derived stem/progenitor cells to improve cardiac function and symptoms in heart failure patients.

Isolation and enrichment of stem cells

Stem cells have the potential to revolutionize tissue regeneration and engineering. Both general types of stem cells, those with pluripotent differentiation potential as well as those with multipotent differentiation potential, are of equal interest. They are important tools to further understanding of general cellular processes, to refine industrial applications for drug target discovery and predictive toxicology, and to gain more insights into their potential for tissue regeneration. This chapter provides an overview of existing sorting technologies and protocols, outlines the phenotypic characteristics of a number of different stem cells, and summarizes their potential clinical applications.

Cell therapy for heart disease: great expectations, as yet unmet

Regenerative medicine is often touted as an achievement of the new millennium, but many approaches to improve health by stimulating the organism's own capacity for healing have existed for a long time. Some components of today's regenerative medicine, however, are indeed fundamentally new developments, and one of those is the concept of increasing the number of contractile cells in the heart to cure heart failure, either by stimulating intrinsic regeneration processes or by transplanting exogenous cells. The aim of this paper is to review the current status of some key aspects of cell therapy and obstacles to clinical translation.

Current status and future prospects for cell transplantation to prevent congestive heart failure

Although most cardiac cell therapy trials have focused on patients with acute myocardial infarction, attempts at "regenerating" chronically failing hearts have also been performed. These studies have entailed use of skeletal myoblasts and bone marrow-derived cells. In the case of skeletal myoblasts, the randomized placebo-controlled myoblast autologous grafting in ischemic cardiomyopathy (MAGIC) trial has failed to show that myoblast injections increased ejection fraction beyond that seen in controls but the finding that the highest dose of myoblasts resulted in a significant antiremodeling effect compared with the placebo group provides an encouraging signal. In the case of bone marrow cells, surgical injections of the mononuclear fraction combined with coronary artery bypass surgery have not shown a substantial benefit but positive results have been reported with intraoperative epicardial injections of CD133(+) progenitors. There are three possible reasons for these mixed results. The first is the marked heterogeneity of cell functionality (particularly in the case of bone marrow), which would expectedly translate into variable clinical outcomes. The second reason is the low rate of sustained engraftment. The third possible explanation is a mismatch between the choice of end points and the presumed mechanism of action of the cells. The initial assumption that adult stem cells could effect myocardial tissue regeneration has led to usual focus on ejection fraction as the major surrogate endpoint. It is now increasingly recognized that adult stem cells, in contrast to their embryonic counterparts, have little if any regenerative capacity and that their presumed beneficial effects more likely involve paracrine signaling, in which case infarct size, perfusion, or left ventricular volumes might be more appropriate markers. Altogether, these observations provide a framework for future research, the results of which will then have to be integrated in the protocol design of second-generation clinical trials.

Therapeutic potential of stem cells in elderly patients with cardiovascular disease

The success of treatment for acute myocardial infarction and chronic myocardial ischemia has improved general medical care in Europe, resulting in an increasing population of patients with chronic and congestive heart failure. By applying currently available therapeutic options the quality of life and lifespan of these patients have both increased. However, amongst patients -- predominantly the elderly -- who remain symptomatic despite intensive medical treatment, autologous bone marrow-derived mononuclear cells may trigger attempts to repopulate lost tissues directly as a novel therapeutic option. In this concised paper the current understanding of stem cell therapy and early clinical experiences are discussed and related to the application of stem cells in elderly patients with myocardial ischemia.

Comparison of different culture conditions for human mesenchymal stromal cells for clinical stem cell therapy

OBJECTIVE

Mesenchymal stromal cells (MSCs) from adult bone marrow (BM) are considered potential candidates for therapeutic neovascularization in cardiovascular disease. When implementing results from animal trials in clinical treatment, it is essential to isolate and expand the MSCs under conditions following good manufacturing practice (GMP). The aims of the study were first to establish culture conditions following GMP quality demands for human MSC expansion and differentiation for use in clinical trials, and second to compare these MSCs with MSCs derived from culture in four media commonly used for MSC cultivation in animal studies simulating clinical stem cell therapy.

MATERIAL AND METHODS

Human mononuclear cells (MNCs) were isolated from BM aspirates by density gradient centrifugation and cultivated in a GMP-accepted medium (EMEA medium) or in one of four other media.

RESULTS

FACS analysis showed that the plastic-adherent MSCs cultured in EMEA medium or in the other four media were identically negative for the haematopoietic surface markers CD45 and CD34 and positive for CD105, CD73, CD90, CD166 and CD13, which in combined expression is characteristic of MSCs. MSC stimulation with vascular endothelial growth factor (VEGF) increased expression of the characteristic endothelial genes KDR and von Willebrand factor; the von Willebrand factor and CD31 at protein level as well as the capacity to develop capillary-like structures.

CONCLUSIONS

We established culture conditions with a GMP compliant medium for MSC cultivation, expansion and differentiation. The expanded and differentiated MSCs can be used in autologous mesenchymal stromal cell therapy in patients with ischaemic heart disease.

Randomized, controlled trial of intramuscular or intracoronary injection of autologous bone marrow cells into scarred myocardium during CABG versus CABG alone

BACKGROUND

Studies of the transplantation of autologous bone marrow cells (BMCs) in patients with chronic ischemic heart disease have assessed effects on viable, peri-infarct tissue. We conducted a single-blinded, randomized, controlled study to investigate whether intramuscular or intracoronary administration of BMCs into nonviable scarred myocardium during CABG improves contractile function of scar segments compared with CABG alone.

METHODS

Elective CABG patients (n = 63), with established myocardial scars diagnosed as akinetic or dyskinetic segments by dobutamine stress echocardiography and confirmed at surgery, were randomly assigned CABG alone (control) or CABG with intramuscular or intracoronary administration of BMCs. The BMCs, which were obtained at the time of surgery, were injected into the mid-depth of the scar in the intramuscular group or via the graft conduit supplying the scar in the intracoronary group. Contractile function was assessed in scar segments by dobutamine stress echocardiography before and 6 months after treatment.

RESULTS

The proportion of patients showing improved wall motion in at least one scar segment after BMC treatment was not different to that observed in the control group (P = 0.092). Quantitatively, systolic fractional thickening in scar segments did not improve with BMC administration. Furthermore, BMCs did not improve scar transmurality, infarct volume, left ventricular volume, or ejection fraction.

CONCLUSION

Injection of autologous BMCs directly into the scar or into the artery supplying the scar is safe but does not improve contractility of nonviable scarred myocardium, reduce scar size, or improve left ventricular function more than CABG alone.

Cell therapy in patients with left ventricular dysfunction due to myocardial infarction

OBJECTIVES

The purpose of this study was to determine the impact of autologous transplantation of mononuclear bone marrow cells on myocardial function in patients with left ventricular (LV) dysfunction due to an acute myocardial infarction.

METHODS

The randomized study included 82 patients with a first acute myocardial infarction treated with a stent implantation. This presentation is a subanalysis of 47 patients with left ventricular dysfunction-EF (ejection fraction) <or= 40%. Group H patients (n = 17) received higher number (100,000,000) of cells; Group L patients (n = 13) received lower number (10,000,000) of cells. The patients of control Group C (n = 17) were not treated with cells. The Doppler tissue imaging and single photon emission computed tomography were performed before cell transplantation and 3 months later.

RESULTS

At 3 months of follow-up, the baseline EF of 35%, 36%, 35% in Groups H, L, and C increased by 6% (P < 0.01 vs. baseline), 5% (P < 0.01 vs. baseline), and 4% (P = NS vs. baseline), respectively, as assessed by single photon emission computed tomography (P = NS between groups). The baseline number of akinetic segments of 6.9, 7.0, and 6.2 in H, L, and C groups decreased by 1.7 (P < 0.01 vs. baseline), 1.5 (P < 0.01 vs. baseline), and 0.7 (P = NS vs. baseline, P = NS between groups), respectively, as demonstrated by echocardiography.

CONCLUSION

In our study, the statistically important effect of transplantation of mononuclear bone marrow cells on myocardial function was not found. Only an insignificant trend toward the improvement of global LV EF fraction was found at 3-month follow-up.

Bone marrow-derived mesenchymal stem cells for treatment of heart failure: is it all paracrine actions and immunomodulation?

Despite significant advances in medical and surgical management of heart failure, mostly of ischaemic origin, the mortality and morbidity associated with it continue to be high. Pluripotent stem cells are being evaluated for treatment of heart failure. Bone marrow-derived mesenchymal stem cells (MSCs) have been extensively studied. Emerging evidence suggests that locally delivered MSCs can lead to an improvement in ventricular function, but the cellular and molecular mechanisms involved remain unclear. Myocardial regeneration, as proposed by many researchers as the underlying mechanism, has failed to convince the scientific community. Recently some authors have ascribed improvement in ventricular function to paracrine actions of MSCs.A lot has been written about the host immune response triggered by embryonic stem cells and the consequent need for immunosuppression. Not enough work has been done on immune interactions involving allogeneic bone marrow cells. Full potential of stem cell therapy can be realised only when we are able to use allogeneic cells. The potential use of MSCs in cellular therapy has recently prompted researchers to look into their interaction with the host immune response. MSCs have immunomodulatory properties. They cause suppression of proliferation of alloreactive T cells in a dose-dependent manner.Tissue injury causes inflammation and release of several chemokines, cytokines and growth factors. They can cause recruitment of bone marrow-derived MSCs to the injured area. We review the literature on paracrine actions and immune interactions of allogeneic MSCs.

The therapeutic potential of stem cells in heart disease

Coronary heart disease and chronic heart failure are common and have an increasing frequency. Although interventional and conventional drug therapy may delay ventricular remodelling, there is no basic therapeutic regime available for preventing or even reversing this process. Chronic coronary artery disease and heart failure impairs quality of life and are associated with subsequent worsening of the cardiac pump function. Numerous studies within the past few years have been demonstrated, that the intracoronary stem cell therapy has to be considered as a safe therapeutic procedure in heart disease, when destroyed and/or compromised heart muscle must be regenerated. This kind of cell therapy with autologous bone marrow cells is completely justified ethically, except for the small numbers of patients with direct or indirect bone marrow disease (e.g. myeloma, leukaemic infiltration) in whom there would be lesions of mononuclear cells. Several preclinical as well as clinical trials have shown that transplantation of autologous bone marrow cells or precursor cells improved cardiac function after myocardial infarction and in chronic coronary heart disease. The age of infarction seems to be irrelevant to regenerative potency of stem cells, since stem cells therapy in old infarctions (many years old) is almost equally effective in comparison to previous infarcts. Further indications are non-ischemic cardiomyopathy (dilative cardiomyopathy) and heart failure due to hypertensive heart disease.