Stem Cell Mobilization by Granulocyte Colony-Stimulating Factor for Myocardial Recovery After Acute Myocardial Infarction

Emerging aspects of cytokine storm in COVID-19: The role of proinflammatory cytokines and therapeutic prospects

COVID-19 has claimed millions of lives during the last 3 years since initial cases were reported in Wuhan, China, in 2019. Patients with COVID-19 suffer from severe pneumonia, high fever, acute respiratory distress syndrome (ARDS), and multiple-organ dysfunction, which may also result in fatality in extreme cases. Cytokine storm (CS) is hyperactivation of the immune system, wherein the dysregulated production of proinflammatory cytokines could result in excessive immune cell infiltrations in the pulmonary tissues, resulting in tissue damage. The immune cell infiltration could also occur in other tissues and organs and result in multiple organs' dysfunction. The key cytokines implicated in the onset of disease severity include TNF-α, IFN-γ, IL-6, IL-1β, GM-CSF, and G-CSF. Controlling the CS is critical in treating COVID-19 disease. Therefore, different strategies are employed to mitigate the effects of CS. These include using monoclonal antibodies directed against soluble cytokines or the cytokine receptors, combination therapies, mesenchymal stem cell therapy, therapeutic plasma exchange, and some non-conventional treatment methods to improve patient immunity. The current review describes the role/s of critical cytokines in COVID-19-mediated CS and the respective treatment modalities.

The Human Coronary Collateral Circulation, Its Extracardiac Anastomoses and Their Therapeutic Promotion

Cardiovascular disease remains the leading global cause of death, and the number of patients with coronary artery disease (CAD) and exhausted therapeutic options (i.e., percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG) and medical treatment) is on the rise. Therefore, the evaluation of new therapeutic approaches to offer an alternative treatment strategy for these patients is necessary. A promising research field is the promotion of the coronary collateral circulation, an arterio-arterial network able to prevent or reduce myocardial ischemia in CAD. This review summarizes the basic principles of the human coronary collateral circulation, its extracardiac anastomoses as well as the different therapeutic approaches, especially that of stimulating the extracardiac collateral circulation via permanent occlusion of the internal mammary arteries.

Cardiac revascularization: state of the art and perspectives

Cardiac ischemia is the leading cause of morbidity and mortality in a worldwide epidemic. The progressive understanding of the mechanisms driving new blood vessel formation has led to numerous attempts to revascularize the ischemic heart in animal models and in humans. Here, we provide an overview of the current state of the art and discuss the major obstacles that have so far limited the clinical success of cardiac revascularization.

Exhaustion of the bone marrow progenitor cell reserve is associated with major events in severe limb ischemia

Lower numbers of progenitor cells (PCs) in peripheral blood (PB) have been associated with cardiovascular events in high-risk populations. Therapies aiming to increase the numbers of PCs in circulation have been developed, but clinical trials did not result in better outcomes. It is currently unknown what causes the reduction in PB PC numbers: whether it is primary depletion of the progenitor cell reserve, or a reduced mobilization of PCs from the bone marrow (BM). In this study, we examine if PB and BM PC numbers predict Amputation-Free Survival (AFS) in patients with Severe Limb Ischemia (SLI). We obtained PB and BM from 160 patients enrolled in a clinical trial investigating BM cell therapy for SLI. Samples were incubated with antibodies against CD34, KDR, CD133, CD184, CD14, CD105, CD140b, and CD31; PC populations were enumerated by flow cytometry. Higher PB CD34⁺ and CD133⁺ PC numbers were related to AFS (Both Hazard Ratio [HR_event] = 0.56, p = 0.003 and p = 0.0007, respectively). AFS was not associated with the other cell populations in PB. BM PC numbers correlated with PB PC numbers and showed similar HRs for AFS. A further subdivision based on relative BM and PB PC numbers showed that BM PC numbers, rather than mobilization, associated with AFS. Both PB and BM PC numbers are associated with AFS independently from traditional risk factor and show very similar risk profiles. Our data suggest that depletion of the progenitor cell reserve, rather than decreased PC mobilization, underlies the association between PB PC numbers and cardiovascular risk.

The effect of pegylated granulocyte colony-stimulating factor on collateral function and myocardial ischaemia in chronic coronary artery disease: A randomized controlled trial

OBJECTIVE

To test the effect of long-term pegfilgrastim on collateral function and myocardial ischaemia in patients with chronic stable coronary artery disease (CAD).

METHODS

This was a prospective clinical trial with randomized 2:1 allocation to pegfilgrastim or placebo for 6 months. The primary study endpoint was collateral flow index (CFI) as obtained during a 1-minute ostial coronary artery balloon occlusion. CFI is the ratio of mean coronary occlusive divided by mean aortic pressure both subtracted by central venous pressure (mm Hg/mm Hg). Secondary endpoints were signs of myocardial ischaemia determined during the same coronary occlusion, that is quantitative intracoronary (i.c.) ECG ST-segment shift (mV) and the occurrence of angina pectoris. Endpoints were obtained at baseline before and at follow-up after three subcutaneous study drug injections.

RESULTS

Collateral flow index in the pegfilgrastim group changed from 0.096 ± 0.076 at baseline to 0.126 ± 0.070 at follow-up (P = 0.0039), while in the placebo group CFI changed from 0.157 ± 0.146 to 0.122 ± 0.043, respectively (P = 0.29); the CFI increment at follow-up was +0.030 ± 0.075 in the pegfilgrastim group and -0.034 ± 0.148 in the placebo group (P = 0.0172). In the pegfilgrastim group, i.c. ECG ST-segment shift changed from +1.23 ± 1.01 mV at baseline to +0.93 ± 0.97 mV at follow-up (P = 0.0049), and in the placebo group, it changed from +0.98 ± 1.02 mV to +1.43 ± 1.09 mV, respectively (P = 0.05). At follow-up, the fraction of patients free from angina pectoris during coronary occlusion had increased in the pegfilgrastim but not in the placebo group.

CONCLUSION

Pegfilgrastim given over the course of 6 months improves collateral function in chronic stable CAD, which is reflected by reduced myocardial ischaemia during a controlled coronary occlusion.

Adult Stem Cells in Vascular Remodeling

Understanding the contribution of vascular cells to blood vessel remodeling is critical for the development of new therapeutic approaches to cure cardiovascular diseases (CVDs) and regenerate blood vessels. Recent findings suggest that neointimal formation and atherosclerotic lesions involve not only inflammatory cells, endothelial cells, and smooth muscle cells, but also several types of stem cells or progenitors in arterial walls and the circulation. Some of these stem cells also participate in the remodeling of vascular grafts, microvessel regeneration, and formation of fibrotic tissue around biomaterial implants. Here we review the recent findings on how adult stem cells participate in CVD development and regeneration as well as the current state of clinical trials in the field, which may lead to new approaches for cardiovascular therapies and tissue engineering.

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.

The Effect of Granulocyte Colony-Stimulating Factor on the Progression of Atherosclerosis in Animal Models: A Meta-Analysis

Background

Atherosclerosis is a common inflammatory disease. Stem cell and endothelial progenitor cell treatments can improve cardiac function after myocardial infarction. Granulocyte colony-stimulating factor (G-CSF) is a mobilisation agent, mobilising stem cells from the bone marrow to circulation in the blood. G-CSF may constitute a treatment of atherosclerosis. We have conducted meta-analysis to evaluate the current evidence for the effect of G-CSF on the progression of atherosclerosis in animal models and to provide reference for preclinical experiments and future human clinical trials of atherosclerosis treatment.

Methods

We searched several databases and conducted a meta-analysis across seven articles using a random-effect model. All statistical analyses were performed using Review Manager Version 5.2 and Stata 12.0.

Results

We found that G-CSF therapy was associated with reduced atherosclerotic lesion area (weighted mean difference (WMD): 7.29%; 95% confidence interval (CI): 2.06-12.52%; P = 0.006). No significant differences in total serum cholesterol (P = 0.54) and triglyceride levels (P = 0.95) were noted in G-CSF treatment groups compared with controls. Multivariable metaregression analysis revealed that the animal type (rabbit, P = 0.022) and frequency of G-CSF administration (>20, P = 0.007) impacted the atherosclerotic lesion area changes.

Conclusion

The meta-analysis suggested that G-CSF treatment might inhibit the progression of atherosclerosis in animal models.

Granulocyte colony-stimulating factor for the treatment of cardiovascular diseases: An update with a critical appraisal

Heart failure and acute myocardial infarction are conditions that are associated with high morbidity and mortality. Significant dysfunction of the heart muscle can occur as the consequence of end-stage chronic cardiovascular diseases or acute ischemic events that are marked by large infarction area and significant tissue necrosis. Despite the remarkable improvement of conventional treatments, a substantial proportion of patients still develops severe heart failure that can only be resolved by heart transplantation or mechanical device implantation. Therefore, novel approaches based on stem-cell therapy can directly modify the disease process and alter its prognosis. The ability of the stem-cells to modify and repair the injured myocardium is a challenging but intriguing concept that can potentially replace expensive and invasive methods of treatment that are associated with increased risks and significant financial costs. In that sense, granulocyte colony-stimulating factor (G-CSF) seems as an attractive treatment approach. Based on the series of pre-clinical experiments and a limited amount of clinical data, it was demonstrated that G-CSF agents possess the ability to mobilize stem-cells from bone marrow and induce their differentiation into cardiomyocytes or endothelial cells when brought into contact with injured regions of the myocardium. However, clinical benefits of G-CSF use in damaged myocardium remain unclear and are the topic of expert discussion. The main goal of this review is to present relevant and up-to-date evidence on G-CSF therapy use in pre-clinical models and in humans and to provide a rationale for its potential clinical applications in the future.

Vascular precursor cells in tissue injury repair

Vascular precursor cells include stem cells and progenitor cells giving rise to all mature cell types in the wall of blood vessels. When tissue injury occurs, local hypoxia and inflammation result in the generation of vasculogenic mediators which orchestrate migration of vascular precursor cells from their niche environment to the site of tissue injury. The intricate crosstalk among signaling pathways coordinates vascular precursor cell proliferation and differentiation during neovascularization. Establishment of normal blood perfusion plays an essential role in the effective repair of the injured tissue. In recent years, studies on molecular mechanisms underlying the regulation of vascular precursor cell function have achieved substantial progress, which promotes exploration of vascular precursor cell-based approaches to treat chronic wounds and ischemic diseases in vital organ systems. Verification of safety and establishment of specific guidelines for the clinical application of vascular precursor cell-based therapy remain major challenges in the field.

Strategy to Prime the Host and Cells to Augment Therapeutic Efficacy of Progenitor Cells for Patients with Myocardial Infarction

Cell therapy in myocardial infarction (MI) is an innovative strategy that is regarded as a rescue therapy to repair the damaged myocardium and to promote neovascularization for the ischemic border zone. Among several stem cell sources for this purpose, autologous progenitors from bone marrow or peripheral blood would be the most feasible and safest cell-source. Despite the theoretical benefit of cell therapy, this method is not widely adopted in the actual clinical practice due to its low therapeutic efficacy. Various methods have been used to augment the efficacy of cell therapy in MI, such as using different source of progenitors, genetic manipulation of cells, or priming of the cells or hosts (patients) with agents. Among these methods, the strategy to augment the therapeutic efficacy of the autologous peripheral blood mononuclear cells (PBMCs) by priming agents may be the most feasible and the safest method that can be applied directly to the clinic. In this review, we will discuss the current status and future directions of priming PBMCs or patients, as for cell therapy of MI.

Sitagliptin plus granulocyte colony-stimulating factor in patients suffering from acute myocardial infarction: A double-blind, randomized placebo-controlled trial of efficacy and safety (SITAGRAMI trial)

OBJECTIVE

In animal models, G-CSF based progenitor cell mobilization combined with a DPP4 inhibitor leads to increased homing of bone marrow derived progenitor cells to the injured myocardium via the SDF1/CXCR4 axis resulting in improved ejection fraction and survival after acute myocardial infarction (AMI).

RESEARCH DESIGN AND METHODS

After successful revascularization in AMI, 174 patients were randomized 1:1 in a multi-centre, prospective, placebo-controlled, parallel group, double blind, phase III efficacy and safety trial to treatment with G-CSF and Sitagliptin (GS) or placebo. Diabetic and non-diabetic patients were included in our trial. The primary efficacy endpoint hierarchically combined global left and right ventricular ejection fraction changes from baseline to 6 months of follow-up (ΔLVEF, ΔRVEF), as determined by cardiac MRI.

RESULTS

At follow-up ΔLVEF as well as ΔRVEF did not differ between the GS and placebo group. Patients in the placebo group had a similar risk for a major adverse cardiac event within 12 months of follow-up as compared to patients under GS.

CONCLUSION

Progenitor cell therapy comprising the use of G-CSF and Sitagliptin after successfully revascularized acute myocardial infarction fails to show a beneficial effect on cardiac function and clinical events after 12 months. (EudraCT: 2007-003,941-34; ClinicalTrials.gov: NCT00650143, funding: Heinz-Nixdorf foundation).

G-CSF Predicts Cardiovascular Events in Patients with Stable Coronary Artery Disease

Granulocyte-colony-stimulating-factor (G-CSF) induces mobilization of progenitor cells but may also exert pro-inflammatory and pro-thrombotic effects. Treatment with recombinant G-CSF after acute myocardial infarction is currently under examination and has been associated with in-stent restenosis. However, it is not known whether plasma levels of endogenous G-CSF are also associated with an increased cardiovascular risk. Therefore we included 280 patients with angiographically proven stable coronary artery disease. G-CSF was measured by specific ELISA and patients were followed for a median of 30 months for the occurrence of major adverse cardiovascular events (MACE: death, myocardial infarction, re-hospitalization). Those with cardiac events during follow-up showed significant higher G-CSF levels (32.3 pg/mL IQR 21.4-40.5 pg/mL vs. 24.6 pg/mL IQR 16.4-34.9 pg/mL; p<0.05) at baseline. Patients with G-CSF plasma levels above the median had a 2-fold increased risk for MACE (p<0.05). This was independent from established cardiovascular risk factors. In addition, G-CSF above the median was a predictor of clinical in-stent restenosis after implantation of bare-metal stents (6.6% vs. 19.4%; p<0.05) but not of drug-eluting stents (7.7% vs. 7.6%; p = 0.98). This data suggests that endogenous plasma levels of G-CSF predict cardiovascular events independently from established cardiac risk factors and are associated with increased in-stent restenosis rates after implantation of bare metal stents.

Granulocyte-colony stimulating factor for large anterior ST-elevation myocardial infarction: rationale and design of the prospective randomized phase III STEM-AMI OUTCOME trial

BACKGROUND

Granulocyte-colony stimulating factor (G-CSF) has been clinically tested in ST-elevation myocardial infarction (STEMI) with mixed results. Our 3-year follow-up data from STEM-AMI trial documented a sustained benefit of G-CSF on adverse ventricular remodeling after large anterior STEMI, when administered early and at a high-dose in patients with left ventricular (LV) dysfunction. The Aim of the present trial is to establish whether G-CSF improves hard clinical long-term outcomes.

METHODS

The STEM-AMI OUTCOME is a prospective, multicenter, randomized, open-label, phase III trial. It will include 1,530 patients with anterior STEMI undergoing primary percutaneous coronary intervention 2 to 24 hours after symptoms onset and with LV ejection fraction ≤45% after successful reperfusion. Patients will be randomized 1:1 to G-CSF and/or standard treatment. The primary end point is a reduced occurrence of all-cause death, recurrence of myocardial infarction, or hospitalization due to heart failure in G-CSF-treated patients. Left ventricular remodeling will be assessed via cardiac ultrasound and a substudy with cardiac magnetic resonance will be carried out in 120 subjects. Accrual and follow-up periods will last 3 and 2 years, respectively.

CONCLUSIONS

The STEM-AMI OUTCOME study is designed to be a rigorous controlled phase III trial with adequate statistical power to conclusively assess efficacy of G-CSF treatment in STEMI.

Immuno-modification of enhancing stem cells targeting for myocardial repair

Despite the controversy in mechanism, rodent and clinical studies have demonstrated beneficial effects of stem/progenitor cell therapy after myocardial infarction (MI). In a rat ischaemic reperfusion MI model, we investigated the effects of immunomodification of CD 34⁺ cells on heart function and myocardial conduction. Bispecific antibody (BiAb), consisting of an anti-myosin light chain antibody and anti-CD45 antibody, injected intravenously was used to direct human CD34⁺ cells to injured myocardium. Results were compared to echocardiography guided intramyocardial (IM) injection of CD34⁺ cells and PBS injected intravenously. Treatment was administered 2 days post MI. Echocardiography was performed at 5 weeks and 3 months which demonstrated LV dilatation prevention and fractional shortening improvement in both the BiAb and IM injection approaches, with BiAb achieving better results. Histological analyses demonstrated a decrease in infarct size and increase in arteriogenesis in both BiAb and IM injection. Electrophysiological properties were studied 5 weeks after treatments by optical mapping. Conduction velocity (CV), action potential duration (APD) and rise time were significantly altered in the MI area. The BiAb treated group demonstrated a more normalized activation pattern of conduction and normalization of CV at shorter pacing cycle lengths. The ventricular tachycardia inducibility was lowest in the BiAb treatment group. Intravenous administration of BiAb offers an effective means of stem cell delivery for myocardial repair post-acute MI. Such non-invasive approach was shown to offer a distinct advantage to more invasive direct IM delivery.

An update on stem cell therapies for acute coronary syndrome

Well into the second decade since its conception, cell transplantation continues to undergo intensive evaluation for the treatment of myocardial infarction. At a mechanistic level, its objectives remain to replace lost cardiac cell mass with new functioning cardiomyocytes and vascular cells, thereby minimizing infarct size and scar formation, and improving clinical outcomes by preventing adverse left ventricular remodeling and recurrent ischemic events. Many different cell types, including pluripotent stem cells and various adult-derived progenitor cells, have been shown to have therapeutic potential in preclinical studies, while early phase human trial experience has provided divergent outcomes and fundamental lessons, emphasizing that there remain key issues to address and challenges to overcome before cell therapy can be applied to wider clinical practice. The purpose of this review is to provide a balanced update on recent seminal developments in this exciting field and look to the next important steps to ensure its forward progression.

Study of peripheral stem cells mobilization as a treatment line of pediatric dilated cardiomyopathy

BACKGROUND

Mobilizing hematopoietic stem cells may be a promising intervention for the treatment of idiopathic dilated cardiomyopathy (IDCM) in infant and children. So the aim of the work is to evaluate the efficacy of granulocyte-colony stimulating factor (G-CSF) as a therapeutic modality in pediatric IDCM.

METHODS

A randomized clinical trial was conducted on 40 pediatric patients with IDCM. They were subjected to history taking, clinical examination, serum lactate dehydrogenase (LDH), total creatinine phosphokinase (CPK), creatinine phosphokinase isoenzyme B (CK-MB) isoenzyme, and peripheral blood CD34(+) cell assessment before and at day 7 after subcutaneous G-CSF injection for 5 consecutive days. Echocardiography was done before and 1, 3 and 6 months after therapy.

RESULTS

Clinical improvement in the form of regression of patients Modified Ross heart failure (MRHC) classification classes. Increased percentage of CD34(+) mobilized cells from the bone marrow, and significant increase in blood counts especially white blood cells 7 days after G-CSF injection. Significant improvement was found in echocardiographic data evaluating systolic function of the heart [Ejection fraction, Fractional shortening and systolic velocity at mitral annulus (Sm)].

CONCLUSIONS

Administration of G-CSF may be beneficial in improving systolic functions of the heart in pediatric IDCM and more studies with a large number of patients are needed.

A multistudy analysis investigating systematic differences in cardiovascular trial results between Europe and Asia

OBJECTIVE

To assess whether there are differences in the results of cardiovascular trials between Europe and Asia using data from an extensive collection of randomised controlled trials.

STUDY DESIGN AND SETTING

All meta-analyses containing randomised controlled trials (RCT's) for the treatment or prevention of cardiovascular diseases were searched for in The Cochrane Library (2000-2008) and MEDLINE (2005-2008). Analysis was then conducted within and over each meta-analysis which satisfied given criteria. Separate estimates of treatment effect were calculated for Europe and Asia in each meta-analysis and then compared. Estimates of a common inter-continental difference over all meta-analyses were also calculated and meta-regression was performed. This was performed for both fatal and non-fatal end points.

RESULTS

The literature search identified 59 meta-analyses that satisfied the inclusion criteria. After exclusion, the number of meta-analyses reporting greater effect sizes in Asia than in Europe was significantly more than would be expected by chance (fatal 12/14, p=0.013; non-fatal 23/32, p=0.020).

CONCLUSIONS

This study provides some evidence that for cardiovascular interventions treatment effect estimation differs between Europe and Asia, with respect to both fatal and non-fatal end points.

Stem cell therapy for heart failure

The last decade has witnessed the publication of a large number of clinical trials, primarily using bone marrow-derived stem cells as the injected cell. Much has been learned through these "first-generation" clinical trials. The considerable advances in our understanding include (1) cell therapy is safe, (2) cell therapy has been modestly effective, (3) the recognition that in humans bone marrow-derived stem cells do not transdifferentiate into cardiomyocytes or new blood vessels (or at least in sufficient numbers to have any effect). The primary mechanism of action for cell therapy is now believed to be through paracrine effects that include the release of cytokines, chemokines, and growth factors that inhibit apoptosis and fibrosis, enhance contractility, and activate endogenous regenerative mechanisms through endogenous circulating or site-specific stem cells. The new direction for clinical trials includes the use of stem cells capable of cardiac lineage, such as endogenous cardiac stem cells.

Cell therapy for human ischemic heart diseases: critical review and summary of the clinical experiences

A decade ago, stem or progenitor cells held the promise of tissue regeneration in human myocardium, with the expectation that these therapies could rescue ischemic myocyte damage, enhance vascular density and rebuild injured myocardium. The accumulated evidence in 2014 indicates, however, that the therapeutic success of these cells is modest and the tissue regeneration involves much more complex processes than cell-related biologics. As the quest for the ideal cell or combination of cells continues, alternative cell types, such as resident cardiac cells, adipose-derived or phenotypic modified stem or progenitor cells have also been applied, with the objective of increasing both the number and the retention of the reparative cells in the myocardium. Two main delivery routes (intracoronary and percutaneous intramyocardial) of stem cells are currently used preferably for patients with recent acute myocardial infarction or ischemic cardiomyopathy. Other delivery modes, such as surgical or intravenous via peripheral veins or coronary sinus have also been utilized with less success. Due to the difficult recruitment of patients within conceivable timeframe into cardiac regenerative trials, meta-analyses of human cardiac cell-based studies have tried to gather sufficient number of subjects to present a statistical compelling statement, reporting modest success with a mean increase of 0.9-6.1% in left ventricular global ejection fraction. Additionally, nearly half of the long-term studies reported the disappearance of the initial benefit of this treatment. Beside further extensive efforts to increase the efficacy of currently available methods, pre-clinical experiments using new techniques such as tissue engineering or exploiting paracrine effect hold promise to regenerate injured human cardiac tissue.

Granulocyte colony-stimulating factor therapy for stem cell mobilization following anterior wall myocardial infarction: the CAPITAL STEM MI randomized trial

BACKGROUND

Small studies have yielded divergent results for administration of granulocyte colony-stimulating factor (G-CSF) after acute myocardial infarction. Adequately powered studies involving patients with at least moderate left ventricular dysfunction are lacking.

METHODS

Patients with left ventricular ejection fraction less than 45% after anterior-wall myocardial infarction were treated with G-CSF (10 μg/kg daily for 4 days) or placebo. After initial randomization of 86 patients, 41 in the placebo group and 39 in the G-CSF group completed 6-month follow-up and underwent measurement of left ventricular ejection fraction by radionuclide angiography.

RESULTS

Baseline and 6-week mean ejection fraction was similar for the G-CSF and placebo groups: 34.8% (95% confidence interval [CI] 32.6%-37.0%) v. 36.4% (95% CI 33.5%-39.2%) at baseline and 39.8% (95% CI 36.2%-43.4%) v. 43.1% (95% CI 39.2%-47.0%) at 6 weeks. However, G-CSF therapy was associated with a lower ejection fraction at 6 months relative to placebo (40.8% [95% CI 37.4%-44.2%] v. 46.0% [95% CI 42.7%-44.3%]). Both groups had improved left ventricular function, but change in left ventricular ejection fraction was lower in patients treated with G-CSF than in those who received placebo (5.7 [95% CI 3.4-8.1] percentage points v. 9.2 [95% CI 6.3-12.1] percentage points). One or more of a composite of several major adverse cardiac events occurred in 8 patients (19%) within each group, with similar rates of target-vessel revascularization.

INTERPRETATION

In patients with moderate left ventricular dysfunction following anterior-wall infarction, G-CSF therapy was associated with a lower 6-month left ventricular ejection fraction but no increased risk of major adverse cardiac events. Future studies of G-CSF in patients with left ventricular dysfunction should be monitored closely for safety.

TRIAL REGISTRATION

ClinicalTrials.gov, no. NCT00394498.

Enhanced stem cell migration mediated by VCAM-1/VLA-4 interaction improves cardiac function in virus-induced dilated cardiomyopathy

Endogenous circulation of bone marrow-derived cells (BMCs) was observed in patients with dilated cardiomyopathy (DCM) who showed cardiac upregulation of Vascular Cell Adhesion Protein-1 (VCAM-1). However, the underlying pathophysiology is currently unknown. Thus, we aimed to analyze circulation, migration and G-CSF-based mobilization of BMCs in a murine model of virus-induced DCM. Mice with coxsackievirus B3 (CVB3) induced DCM and healthy controls were analyzed regarding their myocardial homing factors by PCR. To determine cardiac VCAM-1 expression ELISA and immunohistochemistry were applied. Flow cytometry was performed to analyze BMCs. Cardiac diameters and function were evaluated by echocardiography before and 4 weeks after G-CSF treatment. In murine CVB3-induced DCM an increase of BMCs in peripheral blood and a decrease of BMCs in bone marrow was observed. We found an enhanced migration of Very Late Antigen-4 (VLA-4⁺) BMCs to the diseased heart overexpressing VCAM-1 and higher numbers of CD45⁻CD34⁻Sca-1⁺ and CD45⁻CD34⁻c-kit⁺ cells. Mobilization of BMCs by G-CSF boosted migration along the VCAM-1/VLA-4 axis and reduced apoptosis of cardiomyocytes. Significant improvement of cardiac function was detected by echocardiography in G-CSF-treated mice. Blocking VCAM-1 by a neutralizing antibody reduced the G-CSF-dependent effects on stem cell migration and cardiac function. This is the first study showing that in virus-induced DCM VCAM-1/VLA-4 interaction is crucial for recruitment of circulating BMCs leading to beneficial anti-apoptotic effects resulting in improved cardiac function after G-CSF-induced mobilization.

Cardiac Progenitor Cells in Myocardial Infarction Wound Healing: A Critical Review

SIGNIFICANCE

Coronary artery disease is a major cause of morbidity and mortality as the loss of functional myocardium drives progressive ventricular remodeling and subsequent heart failure. Medical management has significantly improved outcomes for acute myocardial infarction (MI); however, improved strategies are needed to regenerate functional myocardium and prevent the progression to heart failure. Cytotherapy using cardiac progenitor cells (PCs) to regenerate functional myocardium holds tremendous potential; however, a better understanding of PC biology is needed.

RECENT ADVANCES

Reports of cardiac regeneration in lower animals have been reported in the last decade. However, just recently, two separate models of mammalian cardiac regeneration have been published and offer potential to better define PC biology, including PC recruitment, differentiation, proliferation, and integration.

CRITICAL ISSUES

Numerous clinical trials have been completed or are ongoing to evaluate possible cytotherapy options in the treatment of acute and chronic ischemic cardiac disease. To date, results have demonstrated improvements in cardiac function as a result of paracrine effects of cytotherapy, but regeneration of functional myocardium has yet to be observed.

FUTURE DIRECTIONS

Future translation of cardiac PC biology from these models is necessary to promote regenerative cardiac healing following MI and to prevent the progression to heart failure following the loss of functional myocardium. Knowledge gained from mammalian models of cardiac regeneration will allow for the development of therapeutic regimens in the treatment of heart failure.

Bioactive lipids and cationic antimicrobial peptides as new potential regulators for trafficking of bone marrow-derived stem cells in patients with acute myocardial infarction

Acute myocardial infarction (AMI) triggers mobilization of stem cells from bone marrow (BM) into peripheral blood (PB). Based on our observation that the bioactive sphingophospholipids, sphingosine-1 phosphate (S1P), and ceramide-1 phosphate (C1P) regulate trafficking of hematopoietic stem cells (HSCs), we explored whether they also direct trafficking of non-hematopoietic stem cells (non-HSCs). We detected a 3-6-fold increase in circulating CD34+, CD133+, and CXCR4+ lineage-negative (Lin-)/CD45- cells that are enriched in non-HSCs [including endothelial progenitors (EPCs) and very small embryonic-like stem cells (VSELs)] in PB from AMI patients (P<0.05 vs. controls). Concurrently, we measured a ∼3-fold increase in S1P and C1P levels in plasma from AMI patients. At the same time, plasma obtained at hospital admission and 6 h after AMI strongly chemoattracted human BM-derived CD34+/Lin- and CXCR4+/Lin- cells in Transwell chemotaxis assays. This effect of plasma was blunted after depletion of S1P level by charcoal stripping and was further inhibited by the specific S1P1 receptor antagonist such as W146 and VPC23019. We also noted that the expression of S1P receptor 1 (S1P1), which is dominant in naïve BM, is reduced after the exposure to S1P at concentrations similar to the plasma S1P levels in patients with AMI, thus influencing the role of S1P in homing to the injured myocardium. Therefore, we examined mechanisms, other than bioactive lipids, that may contribute to the homing of BM non-HSCs to the infarcted myocardium. Hypoxic cardiac tissue increases the expression of cathelicidin and β-2 defensin, which could explain why PB cells isolated from patients with AMI migrated more efficiently to a low, yet physiological, gradient of stromal-derived factor-1 in Transwell migration assays. Together, these observations suggest that while elevated S1P and C1P levels early in the course of AMI may trigger mobilization of non-HSCs into PB, cathelicidin and β-2 defensin could play an important role in their homing to damaged myocardium.

Granulocyte colony stimulating factor therapy for acute myocardial infarction

BACKGROUND

Acute myocardial infarction (AMI) is the leading cause of death in developed countries, and current treatment modalities have failed to regenerate the dead myocardium resulting from the ischemic damage. Stem cells have the potential to regenerate the damaged myocardium. These cells can be mobilized from the bone marrow by factors such as granulocyte colony stimulating factor (G-CSF).

OBJECTIVES

To assess the effects of stem cell mobilization following granulocyte colony stimulating factor therapy in patients with acute myocardial infarction.

SEARCH METHODS

We searched CENTRAL (The Cochrane Library Issue 4, 2010), MEDLINE (1950 to November week 3, 2010), EMBASE (1980 to 2010 week 48), BIOSIS Previews (1969 to 30 November 2010), ISI Science Citation Index Expanded (1970 to 4 December 2010) and ISI Conference Proceedings Citation Index - Science (1990 to 4 December 2010). We also checked reference lists of articles.

SELECTION CRITERIA

We included randomized controlled trials including participants with a clinical diagnosis of AMI who were randomly allocated to the subcutaneous administration of G-CSF through a daily dose of 2.5, 5 or 10 microgram/kg for four to six days or placebo. No age or other restrictions were applied for the selection of patients.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, assessed trials for eligibility and methodological quality, and extracted data regarding the clinical efficacy and adverse outcomes. Disagreements were resolved by the third author.

MAIN RESULTS

We included seven trials reported in 30 references in the review (354 participants). In all trials, G-CSF was compared with placebo preparations. Dosage of G-CSF varied among studies, ranging from 2.5 to 10 microgram/kg/day. Regarding overall risk of bias, data regarding the generation of randomization sequence and incomplete outcome data were at a low risk of bias; however, data regarding binding of personnel were not conclusive. The rate of mortality was not different between the two groups (RR 0.64, 95% CI 0.15 to 2.80, P = 0.55). Regarding safety, the limited amount of evidence is inadequate to reach any conclusions regarding the safety of G-CSF therapy. Moreover, the results did not show any beneficial effects of G-CSF in patients with AMI regarding left ventricular function parameters, including left ventricular ejection fraction (RR 3.41, 95% CI -0.61 to 7.44, P = 0.1), end systolic volume (RR -1.35, 95% CI -4.68 to 1.99, P = 0.43) and end diastolic volume (RR -4.08, 95% CI -8.28 to 0.12, P = 0.06). It should also be noted that the study was limited since the trials included lacked long enough follow up durations.

AUTHORS' CONCLUSIONS

Limited evidence from small trials suggested a lack of benefit of G-CSF therapy in patients with AMI. Since data of the risk of bias regarding blinding of personnel were not conclusive, larger RCTs with appropriate power calculations and longer follow up durations are required in order to address current uncertainties regarding the clinical efficacy and therapy-related adverse events of G-CSF treatment.

Image-guided therapies for myocardial repair: concepts and practical implementation

Cell- and molecule-based therapeutic strategies to support wound healing and regeneration after myocardial infarction (MI) are under development. These emerging therapies aim at sustained preservation of ventricular function by enhancing tissue repair after myocardial ischaemia and reperfusion. Such therapies will benefit from guidance with regard to timing, regional targeting, suitable candidate selection, and effectiveness monitoring. Such guidance is effectively obtained by non-invasive tomographic imaging. Infarct size, tissue characteristics, muscle mass, and chamber geometry can be determined by magnetic resonance imaging and computed tomography. Radionuclide imaging can be used for the tracking of therapeutic agents and for the interrogation of molecular mechanisms such as inflammation, angiogenesis, and extracellular matrix activation. This review article portrays the hypothesis that an integrated approach with an early implementation of structural and molecular tomographic imaging in the development of novel therapies will provide a framework for achieving the goal of improved tissue repair after MI.

Clinical outcome after stem cell mobilization with granulocyte-colony-stimulating factor after acute ST-elevation myocardial infarction: 5-year results of the STEMMI trial

BACKGROUND

Granulocyte-colony-stimulating factor (G-CSF) has been investigated in trials aiming to promote recovery of myocardial function after myocardial infarction. Long-term safety-data have never been reported. A few studies indicated an increased risk of in-stent re-stenosis. We aimed to investigate clinical events 5 years after inclusion into a randomized trial of G-CSF versus placebo.

METHODS

Seventy-eight patients were randomized, from 2003-2005, to G-CSF or placebo after myocardial infarction. Four patients withdrew consent prior to study treatment and were excluded leaving 36 and 38 in the placebo- and G-CSF groups. Information about all hospital admittances of included patients until 2010 was extracted from a national register. The only censoring event was immigration. The events were combined into four prespecified endpoints: Time to (1) first hospital admittance (all cause), (2) first cardiovascular-related hospital admittance, (3) first major cardiovascular event, and (4) death.

RESULTS

One patient (1%) was lost to follow-up. Four patients (4%) died in the follow-up period, three in the G-CSF group and one in the placebo group (p = 0.4). Hazard ratio for all cause hospital admittance was 0.7 (95% CI 0.38-1.29). The incidence of both new myocardial infarction (p = 1.0) and revascularization procedures (p = 0.4) were similar in the two groups. Survival analyses showed no differences in the occurrence of any of the four prespecified composite endpoints between the two groups (p = 0.6; 0.5; 0.8; 0.3).

CONCLUSIONS

We found no indication of increased risk of adverse events up to 5 years after G-CSF treatment. These results support the continued investigation of G-CSF for cardiac therapy.

Cardiac stem cells: A promising treatment option for heart failure

Cardiovascular diseases are the most common cause of death in the world. The development of heart failure is mainly due to the loss of cardiomyocytes following myocardial infarction and the absence of endogenous myocardial repair. Numerous studies have focused on cardiac stem cells (CSCs) due to their therapeutic benefit, particularly in the treatment of heart failure. It has previously been demonstrated that CSCs are able to promote the regeneration of cardiomyocytes in animals following myocardial infarction. However, the underlying mechanism(s) remain unclear. This review mainly discusses the cardioprotective effect of CSCs and the effect of CSCs on the function of cardiomyocytes, and compares the efficacies of CSCs from rats, mice and humans, thereby contributing to an improved understanding of CSCs as a promising treatment option for heart failure.

Therapeutic role of mobilized bone marrow cells in children with nonischemic dilated cardiomyopathy

Dilated cardiomyopathy is an important cause of congestive cardiac failure in infants and children. Mobilizing hematopoietic progenitor cells is a promising intervention to this deadly disease. Aim. Evaluate granulocyte colony stimulating factor (GCSF) as therapeutic modality in children with idiopathic dilated cardiomyopathy (IDCM). Subjects and Methods. This case-control prospective study was conducted on 20 children with IDCM following up at Cardiology Clinic Children's Hospital, Ain Shams University (group 1) who were compared to another 10 age-, sex-, duration-of-illness-, and systolic-function-matched children with IDCM as control (group 2). They were subjected to history taking, clinical examination, echocardiography, and peripheral blood CD34+ cell assessment before and one week after GCSF intake for 5 consecutive days (by group 1 but not group 2). Results. A significant improvement in echocardiographic data and CD34+-T-cell increase was found in group 1 one week after GCSF intake and for the next 6 months CD34+ T cells percentage of change showed no significant correlation with the that of the left ventricular dimensions and systolic function. Conclusion. Administration of GCSF to children with IDCM resulted in clinical and echocardiographic improvement not correlated to mobilized CD34+ T cells, implying involvement of additional mechanisms over simple stem cell mobilization.

Incidence and clinical significance of cardiac biomarker elevation during stem cell mobilization, apheresis, and intramyocardial delivery: an analysis from ACT34-CMI

BACKGROUND

Cell therapy is a promising therapeutic for a variety of cardiovascular conditions including refractory angina. Elevation of cardiac biomarkers during cell delivery has been frequently described, but the clinical implications have never been studied.

METHODS

ACT34-CMI was a randomized double-blind study assessing the use of intramyocardial delivery of autologous CD34(+) cells for the treatment of refractory angina. Patients (n = 167) underwent G-CSF-mediated (5 μg/[kg day] × 5 days) stem cell mobilization, apheresis, and intramyocardial injection of 1 × 10(5)/kg or 5 × 10(5)/kg CD34(+) cells or placebo. Troponin and creatinine kinase MB were assessed at baseline (n = 161), after cell mobilization and apheresis (n = 153 and 143, respectively), and post-intramyocardial injection (n = 155 and 141, respectively). Major adverse cardiac events (MACE) included death, myocardial infarction, acute congestive heart failure, urgent revascularization, or sustained ventricular arrhythmia.

RESULTS

Seven (4.3%) subjects had troponin above the upper limits of normal (ULN) at baseline. Thirty-four (22.2%) and 11 (7.2%) subjects had troponin levels > ULN or >3× ULN after cell mobilization and apheresis, whereas 72 (46.1%) and 39 (25.2%) subjects had troponin elevations > ULN or >3× ULN, respectively, after intramyocardial injections. Age, but no other preprocedural factors, was predictive of troponin elevation. Periprocedural troponin elevation was not associated with an increased risk of MACE during 1 year, especially in cell therapy-treated patients.

CONCLUSIONS

Troponin elevation is common during stem cell harvesting and intramyocardial administration, is usually asymptomatic, and does not appear to be associated with long-term MACE in subjects undergoing stem cell mobilization and intramyocardial injection.

[Cell therapy for ischemic heart disease]

Ischemic heart disease is the leading cause of death and heart failure worldwide. That is why it is important to develop new therapeutic modalities to decrease mortality and long-term complications in these patients. One of the main lines of research worldwide is myocardial regeneration, using progenitor cells in order to improve systolic and diastolic function in patients with ischemic heart disease, as well as to increase their survival. There have been carried out, with great enthusiasm worldwide, human and animal studies to define the usefulness of stem cells in the management of patients with ischemic heart disease. Today, regenerative therapy in ischemic heart disease is considered a novel therapeutic tool, with substantial theoretical benefits and few side effects. Here we present the scientific principles that support the use of this therapy, discuss the current clinical evidence available; and point out the controversial issues still not clarified on its use and usefulness in the short and long term.

G-CSF stimulation and coronary reinfusion of mobilized circulating mononuclear proangiogenic cells in patients with chronic ischemic heart disease:five-year results of the TOPCARE-G-CSF trial

Prognosis of patients with heart failure remains poor despite improved conventional and interventional treatment regimens. The improvement of neovascularization and repair processes by administration of bone marrow-derived cells modestly improved the recovery after acute myocardial infarction. However, circulating patient-derived cells are reduced in number and function particularly in chronic heart failure. Therefore, we tested the hypothesis whether the mobilization of circulating mononuclear proangiogenic cells (CPCs) by G-CSF may overcome some of these limitations. In the present pilot study, 32 patients with at least 3-month-old myocardial infarction were randomized to G-CSF alone (G-CSF group) or intracoronary infusion of G-CSF-mobilized and cultured CPCs into the infarct-related artery (G-CSF/CPC group). Primary endpoint of the study was safety. Efficacy parameters included serial assessment of LV function, NT-proBNP levels, and cardiopulmonary exercise testing. G-CSF effectively mobilized circulating CD34(+)CD45(+) cells after 5 days in all patients (408 ± 64%) without serious adverse events. At 3 months, NYHA class and global LV function did not show significant improvements in both treatment groups (G-CSF: ΔLVEF 1.6 ± 2.4%; p = 0.10; G-CSF/CPC: ΔLVEF 1.4 ± 4.1%; p = 0.16). In contrast, target area contractility improved significantly in the G-CSF/CPC group. During 5-year follow-up, one patient died after rehospitalization for worsening heart failure. Eleven patients underwent further revascularization procedures. NT-proBNP levels, cardiopulmonary exercise capacity, and NYHA class remained stable in both treatment groups. The results from our pilot trial indicate that administration of G-CSF alone or G-CSF-mobilized and cultured CPCs can be performed safely in patients with chronic ischemic heart disease. However, only minor effects on LV function, NT-proBNP levels, and NYHA classification were observed during follow-up, suggesting that the enhancement of CPCs by G-CSF alone does not substantially improve intracoronary cell therapy effects in patients with chronic ischemic heart failure.

Heart repair and regeneration: recent insights from zebrafish studies

Cardiovascular disease is the leading cause of death in the U.S. and worldwide. Failure to properly repair or regenerate damaged cardiac tissues after myocardial infarction is a major cause of heart failure. In contrast to humans and other mammals, zebrafish hearts regenerate after substantial injury or tissue damage. Here, we review recent progress in studying zebrafish heart regeneration, addressing the molecular and cellular responses in the three tissue layers of the heart: myocardium, epicardium, and endocardium. We also compare different injury models utilized to study zebrafish heart regeneration and discuss the differences in responses to injury between mammalian and zebrafish hearts. By learning how zebrafish hearts regenerate naturally, we can better design therapeutic strategies for repairing human hearts after myocardial infarction.

Gene and cytokine therapy for heart failure: molecular mechanisms in the improvement of cardiac function

Despite significant advances in pharmacological and clinical treatment, heart failure (HF) remains a leading cause of morbidity and mortality worldwide. Many new therapeutic strategies, including cell transplantation, gene delivery, and cytokines or other small molecules, have been explored to treat HF. Recent advancement of our understanding of the molecules that regulate cardiac function uncover many of the therapeutic key molecules to treat HF. Furthermore, a theory of paracrine mechanism, which underlies the beneficial effects of cell therapy, leads us to search novel target molecules for genetic or pharmacological strategy. Gene therapy means delivery of genetic materials into cells to achieve therapeutic effects. Recently, gene transfer technology in the cardiovascular system has been improved and several therapeutic target genes have been started to examine in clinical research, and some of the promising results have been emerged. Among the various bioactive reagents, cytokines such as granulocyte colony-stimulating factor and erythropoietin have been well examined, and a number of clinical trials for acute myocardial infarction and chronic HF have been conducted. Although further research is needed in both preclinical and clinical areas in terms of molecular mechanisms, safety, and efficiency, both gene and cytokine therapy have a great possibility to open the new era of the treatment of HF.

Association of Stat3 with HSF1 plays a critical role in G-CSF-induced cardio-protection against ischemia/reperfusion injury

Granulocyte colony-stimulating factor (G-CSF) has been shown to be cardio-protective against ischemia through activating Jak2/Stat3 pathway, however, the mechanism is unclear. Heat shock transcription factor 1 (HSF1), a definite endogenous protective protein in cardiomyocytes, may interact with Stat family under stress conditions. We hypothesized that G-CSF could induce cardio-protection against ischemia/reperfusion (I/R) through association of HSF1 with Stat3. To test the hypothesis, we built cardiac I/R injury model with HSF1 knockout (KO) mice and wild type (WT) mice by occlusion of the left anterior descending (LAD) coronary artery for 30min and subsequent release of the occlusion for 24h. These mice were administered with G-CSF (100μg/kg/day) or vehicle subcutaneously for 3days before surgery. As expected, G-CSF induced significant cardio-protections against I/R injury, characterized by higher ejection fraction (EF%), lower left ventricular end diastolic pressure (LVEDP), increased dp/dt value and decreased infarct area as compared with the vehicle treatment in WT mice. In HSF1-KO mice, however, these cardio-protections induced by G-CSF were greatly attenuated. Inhibition of oxidative stress-induced cardiomyocyte apoptosis by G-CSF also disappeared due to the deficiency of HSF1 in vitro and in vivo. Furthermore, G-CSF increased the phosphorylation and the association of Stat3 with HSF1, which enhanced transcriptional activity of HSF1. Inhibition of either Stat3 or HSF1 by pharmacological agents suppressed G-CSF-induced association of the two proteins and anti-apoptotic effect on cardiomyocytes. Our data suggest that G-CSF stimulates phosphorylation and association of Stat3 with HSF1 and therefore enhances transcriptional activity of HSF1, leading to the cardio-protection against I/R injury.

Stem cells for cardiac repair in acute myocardial infarction

Despite recent advances in medical therapy, reperfusion strategies, implantable cardioverter-defibrillators and cardiac assist devices, ischemic heart disease is a frequent cause of morbidity and mortality worldwide. Cell therapy has been introduced as a new treatment modality to regenerate lost cardiomyocytes. At present, several cell types seem to improve left ventricular function in animal models as well as in humans, but evidence for true generation of new myocardium is confined to the experimental models. In the clinical perspective, myocardial regeneration has been replaced by myocardial repair, as other mechanisms seem to be involved. Clinical studies on adult stem cells suggest, at best, moderate beneficial effects on surrogate end points, but some applications may qualify for evaluation in larger trials. Complete regeneration of the myocardium by cell therapy after a large myocardial infarction is still visionary, but pluripotent stem cells and tissue engineering are important tools to solve the puzzle.

Hematopoietic cytokines for cardiac repair: mobilization of bone marrow cells and beyond

Hematopoietic cytokines, traditionally known to influence cellular proliferation, differentiation, maturation, and lineage commitment in the bone marrow, include granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor, stem cell factor, Flt-3 ligand, and erythropoietin among others. Emerging evidence suggests that these cytokines also exert multifarious biological effects on diverse nonhematopoietic organs and tissues. Although the precise mechanisms remain unclear, numerous studies in animal models of myocardial infarction (MI) and heart failure indicate that hematopoietic cytokines confer potent cardiovascular benefits, possibly through mobilization and subsequent homing of bone marrow-derived cells into the infarcted heart with consequent induction of myocardial repair involving multifarious mechanisms. In addition, these cytokines are also known to exert direct cytoprotective effects. However, results from small-scale clinical trials of G-CSF therapy as a single agent after acute MI have been discordant and largely disappointing. It is likely that cardiac repair following cytokine therapy depends on a number of known and unknown variables, and further experimental and clinical studies are certainly warranted to accurately determine the true therapeutic potential of such therapy. In this review, we discuss the biological features of several key hematopoietic cytokines and present the basic and clinical evidence pertaining to cardiac repair with hematopoietic cytokine therapy.

A pilot study of chronic, low-dose epoetin-{beta} following percutaneous coronary intervention suggests safety, feasibility, and efficacy in patients with symptomatic ischaemic heart failure

AIMS

Low-dose epoetin-β improved neo-angiogenesis and cardiac regeneration in experimental models of ischaemic cardiomyopathy without raising haemoglobin. No clinical study has tested this approach to date.

METHODS AND RESULTS

We performed a randomized, placebo-controlled, double-blind, single-centre study of 35 IU/kg body weight epoetin-β given subcutaneously once weekly for 6 months started within 3 weeks after successful percutaneous coronary intervention (PCI). Patients were included if they presented with a lesion within the proximal segment of the left anterior descending artery, the right coronary artery, or circumflex and had symptomatic heart failure. Patients with ST-segment elevation due to an acute myocardial infarct were excluded. The outcome variables were measured at baseline and at 6 months. Primary outcome measure was individual change in ejection fraction; secondary outcome was safety, change in N-terminal pro-brain natriuretic peptide, and peak VO(2). Twenty-four patients completed the 6-month treatment course. No adverse event related to the treatment occurred. Low-dose epoetin-β following PCI significantly improved global ejection fraction as measured by echocardiography (EPO: ΔEF 5.2 ± 2.0%, P= 0.013; placebo: ΔEF 0.3 ± 1.6%, P= 0.851; P= 0.019 for the inter-group difference) and cardiac magnetic resonance (EPO: ΔEF 3.1 ± 1.6%, P= 0.124; placebo: -1.9 ± 1.2%, P= 0.167; P= 0.042 for the inter-group difference). N-terminal pro-brain natriuretic peptide levels decreased in both groups without significant inter-group differences. Peak VO(2) levels increased significantly by 3.9 ± 1.1% (P< 0.05) in the EPO group, whereas in the placebo group the increase did not reach statistical significance (Δpeak VO(2) 3.0 ± 1.6, P = ns). No significant difference regarding peak VO(2) was observed between the EPO and placebo groups.

CONCLUSIONS

Low-dose epoetin-β treatment following PCI is safe and feasible, and has possible beneficial effects on global ejection fraction and measures of exercise capacity. Extended low-dose epoetin-β treatment warrants further mechanistic studies as well as larger clinical trials.

CLINICAL TRIAL REGISTRATION INFORMATION

NCT00568542.

Sonic hedgehog-induced functional recovery after myocardial infarction is enhanced by AMD3100-mediated progenitor-cell mobilization

OBJECTIVES

This study was designed to compare the effectiveness of Sonic hedgehog (Shh) gene transfer, AMD3100-induced progenitor-cell mobilization, and Shh-AMD3100 combination therapy for treatment of surgically induced myocardial infarction (MI) in mice.

BACKGROUND

Shh gene transfer improves myocardial recovery by up-regulating angiogenic genes and enhancing the incorporation of bone marrow-derived progenitor cells (BMPCs) in infarcted myocardium. Here, we investigated whether the effectiveness of Shh gene therapy could be improved with AMD3100-induced progenitor-cell mobilization.

METHODS

Gene expression and cell function were evaluated in cells cultured with medium collected from fibroblasts transfected with plasmids encoding human Shh (phShh). MI was induced in wild-type mice, in matrix metalloproteinase (MMP)-9 knockout mice, and in mice transplanted with bone marrow that expressed green-fluorescent protein. Mice were treated with 100 μg of phShh (administered intramyocardially), 5 mg/kg of AMD3100 (administered subcutaneously), or both; cardiac function was evaluated echocardiographically, and fibrosis, capillary density, and BMPC incorporation were evaluated immunohistochemically.

RESULTS

phShh increased vascular endothelial growth factor and stromal cell-derived factor 1 expression in fibroblasts; the medium from phShh-transfected fibroblasts increased endothelial-cell migration and the migration, proliferation, and tube formation of BMPCs. Combination therapy enhanced cardiac functional recovery (i.e., left ventricular ejection fraction) in wild-type mice, but not in MMP-9 knockout mice, and was associated with less fibrosis, greater capillary density and smooth muscle-containing vessel density, and enhanced BMPC incorporation.

CONCLUSIONS

Combination therapy consisting of intramyocardial Shh gene transfer and AMD3100-induced progenitor-cell mobilization improves cardiac functional recovery after MI and is superior to either individual treatment for promoting therapeutic neovascularization.

Granulocyte-colony-stimulating Factor for Acute Ischemic Stroke: A Randomized Controlled Trial (STEMTHER)

Granulocyte-colony-stimulating factor (G-CSF) functions both as a neuroprotectant and a stimulator of autologous bone marrow stem cell release. Therefore, administration of G-CSF should improve the outcome of stroke. Here, we examine the safety of using G-CSF to treat acute ischemic stroke using a randomized controlled trial involving 20 adult patients presenting with ischemia in the carotid region within 48 h of onset. The experimental group (n = 10) received subcutaneous G-CSF injections (10 mg kg(-1) day(-1)) in addition to conventional therapy for 5 days. The primary outcome was motor function as measured by the modified Rankin Scale 180 days post-stroke. Safety was evaluated according to the frequency of hemorrhagic transformation of infarctions and serious adverse events. Only six patients in the experimental group completed full course of treatment, while four patients (three in the control and one in the experimental group) were lost to follow-up. We found the experimental and control groups did not differ significantly in either neurological impairment or degree of disability/dependence at 180 days post-stroke. We conclude that while adding G-CSF (10 mg kg(-1) day(-1)) to acute ischemic stroke therapy for 5 days is safe, its efficacy remains unproven.