Global Contractility Increment in Nonischemic Dilated Cardiomyopathy after Free Wall-Only Intramyocardial Injection of Autologous Bone Marrow Mononuclear Cells: An Insight over Stem Cells Clinical Mechanism of Action

The efficacy of bone marrow mononuclear stem cell transplantation in patients with non-ischemic dilated cardiomyopathy-a meta analysis

Cardiomyopathy refers to a wide spectrum of heart pathologies that interfere with normal heart function. Management options of patients with cardiomyopathy depended mainly on the severity of the condition. Lifestyle modifications and regular exercise together with a healthy diet is compatible for mild conditions. Severe conditions, however, rely on medications or surgery. Here, we aim to investigate the efficacy of bone marrow mononuclear stem cell transplantation in patients with dilated cardiomyopathy. We searched PubMed, Scopus, and Cochrane CENTRAL for relevant clinical trials and excluded observational studies. We performed the quality assessment of this study following GRADE guidelines. The assessment of the risk of bias was performed by the Cochrane's risk of bias tool. We present an analysis of the following outcomes: left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), and six minutes walking test. Data were pooled as mean differences (MD) and relative confidence intervals (CI). The analysis of 667 patients from 11 studies receiving autologous bone marrow cell therapy for non-ischemic dilated cardiomyopathy is presented. A total of 338 patients were allocated to the treatment group, and 329 participants entered the control group. The mean age of the patients in the treatment group is 52.4 ± 4.3 years, while that of the control is 53.7 ± 3.7 years. Seven studies (14.18-23) reported transplantation through the intracoronary route. Table 1 shows a summary of the baseline characteristics of the included studies and participants, the number of injected cells, and the type of injected cells in each trial. Table 2 summarizes and illustrates the previous treatment history of included patients in each trial, as well as the baseline values of different scores used as outcome measures in this analysis. We found that bone marrow mononuclear stem cell therapy leads to significantly increased LVEF (MD = 4.54%, 95% CI [3.52, 5.56], P < 0.0001). Patients in the transplant group experienced less left ventricular end-diastolic diameter (millimeter) than the control arm (MD = -1.86 mm, 95% CI [-4.01, 0.29], P = 0.09). Additionally, Patients in the transplant group could walk 28.53 m more than the controls (MD = 28.53 m, 95% CI [2.51, 54.55], P = 0.03). Transplantation of bone marrow stem cells yields acceptable results regarding left ventricular ejection fraction and lowers the left ventricular end-diastolic diameter. Additionally, the six minutes walking test is improved in the transplant group. Table 1 Demographic data about the included participants Study Year Sample size Age, years Males, n (%) Diabetics, n (%) Route of administration Number of injected cells Type of injected cells TTT Control TTT Control TTT Control TTT Control Bartolucci 2015 12 11 58 ± 14 57 ± 11 8 (66.7) 9 (81.8) 2 (16.7) 1 (9.1) Intracoronary 1.94 × 10^6 CD34 +  Bocchi 2010 8 15 51 ± 15 NR NR NR NR Intracoronary NR NR Frljak 2018 30 30 56 ± 9 54 ± 11 27 (90) 26 (87) 3 (10) 2 (6) Trans-endocardial NR CD34 +  Hamshere 2015 15 14 57.67 ± 12.32 56.79 ± 9.8 10 12 9(59.9%) 8(57.1%) Intracoronary 4.91 × 10^6 CD34 +  Hu 2011 31 29 56.61 ± 9.72 58.27 ± 8.86 NR NR NR NR NR NR NR Matrino 2015 82 78 51 ± 11.1 49.6 ± 11.1 73.1 68.3 NR NR Intracoronary 10^8 TTT, CD45, CD105, and CD133 Sant'Anna 2014 20 10 48.3 ± 8.71 51.6 ± 7.79 13(65) 5 (50%) NR NR Intra-myocardial 1.06 × 108 CD3, CD4, CD14, CD34, CD38, and CD45 Seth 2010 41 40 45 ± 15 49 ± 9 33 35 NR NR NR 168 × 10^6 Bone marrow mononuclear cells Vrtovec 2011 28 27 52 ± 8 54 ± 7 26 (93) 23 (85) NR NR Intracoronary 123 × 10^6 CD34 +  Vrtovec 2013 55 55 53 ± 8 55 ± 7 45 (82) 44 (80) NR NR Intracoronary NR NR Xiao 2017 16 20 49.5 ± 11.6 54.4 ± 11.6 9 (56.3) 14 (70.0) 6 (37.5) 5 (29.4) Intracoronary infusion (4.9 ± 1.7) × 108 (CD29, CD34, CD44, CD45, and CD166) Data are reported as mean ± SD or n (%) unless proved otherwise TTT treatment group, NR not reported Table 2 Previous history of treatment and drug intake by the patients Study Year Medical therapy, n (%) Baseline scores, mean (SD) Beta blockers ACE inhibitors Digoxin Diuretics LVEF, % LVEDD, mm Six minutes-walk test^* TTT Control TTT Control TTT Control TTT Control TTT Control TTT Control TTT Control Bartolucci 2015 10 (83.3) 8 (72.7) NR NR 3 (25) 3 (27.3) 11 (91.6) 10 (90.9) 26.8 ± 4.9 30.3 ± 6.3 NR NR NR NR Bocchi 2010 NR NR NR NR NR NR NR NR 21.8 ± 3.8 30.6 ± 7.3 79 (10) 78 (12) NR NR Frljak 2018 30 (100) 30 (100) 31 (100) 32 (100) 2 (7) 3 (10) 32 (100) 33 (100) 32.2 ± 9.3 31.1 ± 7.8 NR NR NR NR Hamshere 2015 13 14 15 13 6 2 9 8 32.93 ± 16.46 29.75 ± 9.2 NR NR NR NR Hu* 2011 NR NR NR NR NR NR NR NR NR NR NR NR 466 (402, 495) 448 (383, 497) Matrino 2015 9 (11) 8 (10.2) 53 (64.1) 48 (61.1) 63 (77) 62 (79) 74 (89.7) 69 (88.9) 23.8 ± 7.2 24.7 ± 7.0 NR NR 347.3(146.7) 349.8(139.7) Sant'Anna 2014 NR NR NR NR NR NR NR NR NR NR NR NR 358.5 (88.69) 353 (86.67) Seth 2010 29 (70) 29 (72) 41 (100) 40 (100) NR NR NR NR NR NR NR NR NR NR Vrtovec 2011 21 (75) 22 (81) NR NR 5 (18) 6 (22) 26 (93) 24 (88) 25.6 ± 5.1 26.7 ± 3.9 69 ± 10 70 ± 7 NR NR Vrtovec 2013 43 (79) 46 (84) 51 (93) 54 (98) 9 (16) 11 (20) 51 (93) 20 (91) 24.3 ± 6.5 25.7 ± 4.1 69 ± 10 70 ± 7 NR NR Xiao 2017 16 (100) 20 (100) 16 (100) 19 (95) 4 (25.0) 8 (40.0) 5 (31.3) 6 (30.0) 33.1 ± 3.9 33.7 ± 4.0 NR NR 355.0 ± 91.2 323.3 ± 89.4 Data are reported as mean ± SD or n (%) unless proved otherwise TTT treatment group, NR not reported ^*Data are reported as median (IQR).

Effects of stem cells on non-ischemic cardiomyopathy: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AIMS

To assess the impacts of stem cell therapy on clinical outcomes in patients with non-ischemic cardiomyopathy (NICM). The effect of stem cell therapy on prognosis is unclear and controversial.

METHODS

The authors performed a systematic review and meta-analysis of the effects of autologous stem cell transplantation in patients with NICM on a composite outcome of all-cause mortality and heart transplantation, left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), New York Heart Association (NYHA) classification, 6-minute walk test (6-MWT) distance and serum brain natriuretic peptide (BNP) level, considering studies published before March 19, 2020.

RESULTS

Twelve trials with 623 subjects met inclusion criteria. Compared with the control group, stem cell therapy improved LVEF (weighted mean difference [WMD], 4.08%, 95% confidence interval [CI], 1.93-6.23, P = 0.0002) and 6-MWT distance (WMD, 101.49 m, 95% CI, 45.62-157.35, P = 0.0004) and reduced BNP level (-294.94 pg/mL, 95% CI, -383.97 to -205.90, P < 0.00001) and NYHA classification (-0.70, 95% CI, -0.98 to -0.43, P < 0.00001). However, LVEDD showed no significant difference between the two groups (WMD, -0.09 cm, 95% CI, -0.23 to 0.06, P = 0.25). In 10 studies (535 subjects) employing the intracoronary route for cell delivery, mortality and heart transplantation were decreased (risk ratio [RR], 0.73, 95% CI, 0.52-1.00, P = 0.05). Furthermore, in four studies (248 subjects) with peripheral CD34+ cells, either all-cause mortality (RR, 0.44, 95% CI, 0.23-0.86, P = 0.02) or mortality and heart transplantation (RR, 0.45, 95% CI, 0.27-0.77, P = 0.003) improved in the treatment group compared with the control. The trial sequential analysis suggested the information size of LVEF, 6-WMT and BNP has been adequate for evidencing the benefits of stem cells on NICM. However, to determine the potential survival benefit, more clinical data are required to make the statistical significance in meta-analysis more conclusive.

CONCLUSIONS

This meta-analysis demonstrates that stem cell therapy may improve survival, exercise capacity and cardiac ejection fraction in NICM, which suggests that stem cells are a promising option for NICM treatment.

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

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

Randomised, double-blind, placebo-controlled clinical trial for evaluating the efficacy of intracoronary injection of autologous bone marrow mononuclear cells in the improvement of the ventricular function in patients with idiopathic dilated myocardiopathy: a study protocol

Background

Cellular therapies have been increasingly applied to diverse human diseases. Intracoronary infusion of bone marrow-derived mononuclear cells (BMMNC) has demonstrated to improve ventricular function after acute myocardial infarction. However, less information is available about the role of BMMNC therapy for the treatment of dilated myocardiopathies (DCs) of non-ischemic origin. This article presents the methodological description of a study aimed at investigating the efficacy of intracoronary injection of autologous BMMNCs in the improvement of the ventricular function of patients with DC.

Methods

This randomised, placebo-controlled, double-blinded phase IIb clinical trial compares the improvement on ventricular function (measured by the changes on the ejection fraction) of patients receiving the conventional treatment for DC in combination with a single dose of an intracoronary infusion of BMMNCs, with the functional recovery of patients receiving placebo plus conventional treatment. Patients assigned to both treatment groups are monitored for 24 months. This clinical trial is powered enough to detect a change in Left Ventricular Ejection Fraction (LVEF) equal to or greater than 9%, although an interim analysis is planned to re-calculate sample size.

Discussion

The study protocol was approved by the Andalusian Coordinating Ethics Committee for Biomedical Research (Comité Coordinador de Ética en Investigación Biomédica de Andalucia), the Spanish Medicines and Medical Devices Agency (Agencia Española de Medicamentos y Productos Sanitarios), and is registered at the EU Clinical Trials Register (EudraCT: 2013–002015-98). The publication of the trial results in scientific journals will be performed in accordance with the applicable regulations and guidelines to clinical trials.

Trial registration

ClinicalTrials.gov Identifier NCT02033278 (First Posted January 10, 2014): https://clinicaltrials.gov/ct2/show/NCT02033278; EudraCT number: 2013–002015-98, EU CT Register: https://www.clinicaltrialsregister.eu/ctr-search/search?query=2013-002015-98. Trial results will also be published according to the CONSORT statement at conferences and reported peer-reviewed journals.

Gene therapy for refractory angina and cell therapy for heart failure: experience of a Brazilian research group

Cell therapy has shown impressive effects in experimental cardiomyopathy models. To a lesser extent, gene therapy has also been studied. In both cases, translation to clinical therapy has been disappointing. This paper is intended to describe the experience and achievements of a multicenter working group located in Porto Alegre, southern Brazil, in experimental and translational research projects for cell-based and gene therapy methods in the treatment of dilated and ischemic cardiomyopathies. The results of preclinical and clinical studies showed that bone marrow mononuclear stem cells indeed have an effect in improving myocardial perfusion and contractile function, but the overall results are poorly translated to the clinical level. Gene therapy studies with direct myocardial injections of naked VEGF 165 plasmid showed improvement in myocardial perfusion and function in animal models. A randomized clinical trial found that this method is safe and improved myocardial perfusion, but the benefits disappeared after 1 year. An animal experiment associating VEGF 165 with angiopoietin was undertaken in mini pigs to extend the durability of that therapy. In conclusion, our efforts to better understand the mechanisms and functions of gene and cell-based therapies in cardiology resulted in significant findings and propose a future look at cell-free therapeutic approaches.

Mesenchymal stem cells from sternum: the type of heart disease, ischemic or valvular, does not influence the cell culture establishment and growth kinetics

Background

In an attempt to increase the therapeutic potential for myocardial regeneration, there is a quest for new cell sources and types for cell therapy protocols. The pathophysiology of heart diseases may affect cellular characteristics and therapeutic results.

Methods

To study the proliferative and differentiation potential of mesenchymal stem cells (MSC), isolated from bone marrow (BM) of sternum, we made a comparative analysis between samples of patients with ischemic (IHD) or non-ischemic valvular (VHD) heart diseases. We included patients with IHD (n = 42) or VHD (n = 20), with average age of 60 years and no differences in cardiovascular risk factors. BM samples were collected (16.4 ± 6 mL) and submitted to centrifugation with Ficoll-Paque, yielding 4.5 ± 1.5 × 10⁷ cells/mL.

Results

Morphology, immunophenotype and differentiation ability had proven that the cultivated sternal BM cells had MSC features. The colony forming unit-fibroblast (CFU-F) frequency was similar between groups (p = 0.510), but VHD samples showed positive correlation to plated cells vs. CFU-F number (r = 0.499, p = 0.049). The MSC culture was established in 29% of collected samples, achieved passage 9, without significant difference in expansion kinetics between groups (p > 0.05). Dyslipidemia and the use of statins was associated with culture establishment for IHD patients (p = 0.049 and p = 0.006, respectively).

Conclusions

Together, these results show that the sternum bone can be used as a source for MSC isolation, and that ischemic or valvular diseases do not influence the cellular yield, culture establishment or in vitro growth kinetics.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1262-0) contains supplementary material, which is available to authorized users.

Exploring pericyte and cardiac stem cell secretome unveils new tactics for drug discovery

Ischaemic diseases remain a major cause of morbidity and mortality despite continuous advancements in medical and interventional treatments. Moreover, available drugs reduce symptoms associated with tissue ischaemia, without providing a definitive repair. Cardiovascular regenerative medicine is an expanding field of research that aims to improve the treatment of ischaemic disorders through restorative methods, such as gene therapy, stem cell therapy, and tissue engineering. Stem cell transplantation has salutary effects through direct and indirect actions, the latter being attributable to growth factors and cytokines released by stem cells and influencing the endogenous mechanisms of repair. Autologous stem cell therapies offer less scope for intellectual property coverage and have limited scalability. On the other hand, off-the-shelf cell products and derivatives from the stem cell secretome have a greater potential for large-scale distribution, thus enticing commercial investors and reciprocally producing more significant medical and social benefits. This review focuses on the paracrine properties of cardiac stem cells and pericytes, two stem cell populations that are increasingly attracting the attention of regenerative medicine operators. It is likely that new cardiovascular drugs are introduced in the next future by applying different approaches based on the refinement of the stem cell secretome.

Cell Therapy in Ischemic Heart Disease: Interventions That Modulate Cardiac Regeneration

The incidence of severe ischemic heart disease caused by coronary obstruction has progressively increased. Alternative forms of treatment have been studied in an attempt to regenerate myocardial tissue, induce angiogenesis, and improve clinical conditions. In this context, cell therapy has emerged as a promising alternative using cells with regenerative potential, focusing on the release of paracrine and autocrine factors that contribute to cell survival, angiogenesis, and tissue remodeling. Evidence of the safety, feasibility, and potential effectiveness of cell therapy has emerged from several clinical trials using different lineages of adult stem cells. The clinical benefit, however, is not yet well established. In this review, we discuss the therapeutic potential of cell therapy in terms of regenerative and angiogenic capacity after myocardial ischemia. In addition, we addressed nonpharmacological interventions that may influence this therapeutic practice, such as diet and physical training. This review brings together current data on pharmacological and nonpharmacological approaches to improve cell homing and cardiac repair.

Myocyte renewal and therapeutic myocardial regeneration using various progenitor cells

Whereas the demand on effective treatment options for chronic heart failure is dramatically increasing, the recent recognition of physiological and pathological myocyte turnover in the adult human heart provided a fundamental basis for the therapeutic regeneration. Divergent modalities were experimentally introduced to this field, and selected ones have been applied clinically; the history began with skeletal myoblasts and bone-marrow-derived cells, and lately mesenchymal stem/stromal cells and resident cardiac cells joined the repertoire. Among them, autologous transplantation of c-kit-positive cardiac stem cells in patients with chronic ventricular dysfunction resulted in an outstanding outcome with long-lasting effects without increasing major adverse events. To further optimize currently available approaches, we have to consider multiple factors, such as the targeting disease, the cell population and number to be administered, and the timing and the route of cell delivery. Exploration of the consequence of the previous clinical trials would allow us to envision an ideal cellular therapy for various cardiovascular disorders.

Direct intramyocardial transthoracic transplantation of bone marrow mononuclear cells for non-ischemic dilated cardiomyopathy: INTRACELL, a prospective randomized controlled trial

Objective

We tested the hypothesis that direct intramyocardial injection of bone marrow mononuclear cells in patients with non-ischemic dilated cardiomyopathy can improve left ventricular function and physical capacity.

Methods

Thirty non-ischemic dilated cardiomyopathy patients with left ventricular ejection fraction <35% were randomized at a 1:2 ratio into two groups, control and treated. The bone marrow mononuclear cells group received 1.06±108 bone marrow mononuclear cells through mini-thoracotomy. There was no intervention in the control group. Assessment was carried out through clinical evaluations as well as a 6-min walk test, nuclear magnectic resonance imaging and echocardiogram.

Results

The bone marrow mononuclear cells group showed a trend toward left ventricular ejection fraction improvement, with magnectic resonance imaging - at 3 months, showing an increase from 27.80±6.86% to 30.13±9.06% (P=0.08) and returning to baseline at 9 months (28.78%, P=0.77). Magnectic resonance imaging showed no changes in left ventricular ejection fraction during follow-up of the control group (28.00±4.32%, 27.42±7.41%, and 29.57±4.50%). Echocardiogram showed left ventricular ejection fraction improved in the bone marrow mononuclear cells group at 3 months, 25.09±3.98 to 30.94±9.16 (P=0.01), and one year, 30.07±7.25% (P=0.001). The control group showed no change (26.1±4.4 vs 26.5±4.7 and 30.2±7.39%, P=0.25 and 0.10, respectively). Bone marrow mononuclear cells group showed improvement in New York Heart Association functional class, from 3.40±0.50 to 2.41±0.79 (P=0.002); patients in the control group showed no change (3.37±0.51 to 2.71±0.95; P=0.17). Six-minute walk test improved in the bone marrow mononuclear cells group (348.00±93.51m at baseline to 370.41±91.56m at 12 months, P=0.66) and there was a non-significant decline in the control group (361.25±90.78m to 330.00±123.42m after 12 months, P=0.66). Group comparisons were non-significant.

Conclusion

The trend of intragroup functional and subjective improvement was not confirmed when compared to the control group. Direct intramyocardial application of bone marrow mononuclear cells in non-ischemic dilated cardiomyopathy was not associated with significant changes in left ventricular function. Differences observed within the bone marrow mononuclear cells group could be due to placebo effect or low statistical power.

Intracoronary transplantation of CD34(+) cells is associated with improved myocardial perfusion in patients with nonischemic dilated cardiomyopathy

BACKGROUND

We investigated the effects of intracoronary transplantation of CD34(+) cells on myocardial perfusion in patients with nonischemic dilated cardiomyopathy (DCM).

METHODS AND RESULTS

We enrolled 21 patients with DCM (left ventricular ejection fraction [LVEF] <40%, New York Heart Association functional class III) who underwent peripheral stem cell mobilization with granulocyte-colony stimulating factor (G-CSF). CD34(+) cells were collected by means of apheresis. Patients underwent myocardial perfusion imaging, and CD34(+) cells were injected in the coronary artery supplying viable segments with reduced myocardial perfusion and regional dysfunction. Myocardial perfusion imaging was repeated 6 months later. Clinical response to stem cell therapy was predefined as a change in LVEF >5%. The majority of patients were men (81%) with an overall mean age 53 ± 9 years, LVEF 25 ± 5%, and 6-minute walking distance 354 ± 71 m. Myocardial perfusion defects at rest were observed in 86% of patients and were more common in the left anterior descending territory (50%). At 6 months' follow-up, there was a significant improvement in rest myocardial perfusion scores (6.3 ± 5.8 vs 3.1 ± 4.3; P < .001), LVEF (25 ± 7% vs 29 ± 8%; P = .005), and 6-minute walking distance (354 ± 71 m vs 404 ± 91 m; P < .001). Responders to stem cell therapy had lower summed rest perfusion score at both baseline (3.2 ± 3.0 vs 9.1 ± 6.3; P = .015) and follow-up (1.0 ± 1.5 vs 5.0 ± 5.1; P = .028).

CONCLUSIONS

CD34(+) cell transplantation may lead to improved myocardial perfusion in patients with nonischemic DCM. Patients with less severe myocardial perfusion defects at baseline may have an increased likelihood to respond to intracoronary CD34(+) cell transplantation.

Functional improvement in patients with dilated cardiomyopathy after the intracoronary infusion of autologous bone marrow mononuclear cells

INTRODUCTION AND OBJECTIVES

Different studies have shown improvement in patients with idiopathic nonischemic dilated cardiomyopathy treated with cell-therapy. However, factors influencing responsiveness are not well known. This trial investigates functional changes and factors influencing the 6-month gain in ejection fraction in 27 patients with dilated cardiomiopathy treated with intracoronary cell-therapy.

METHODS

Patients received intracoronary infusion of autologous bone-marrow mononuclear cells (mean infused, 10.2 [2.9]×10(8)). Flow cytometry and functional analyses of the cells were also performed.

RESULTS

The 6-month angiographic gain in ejection fraction ranged from -9% to 34% (mean, 9%). These changes were distinguished into 2 groups: 21 patients (78%) with a significant improvement at the 6-month evaluation (mean gain, 14 [7]%), and 6 patients who had no response (mean gain, -5 [3]%). The responders were younger as compared to the nonresponders (50 [12] years vs 62 [9] years; P<.04). There was an inverse correlation (r=-0.41; P<.003) between the gain in ejection fraction and the high density lipoprotein level, suggesting higher functional gain with low high density lipoprotein levels. The 24 h migratory capability of the infused cells was significantly reduced in the responders' group (5.4 [1.7]×10(8) vs 8.1 [2.3]×10(8); P<.009 for vascular endothelial growth factor and 5.8 [1.7]×10(8) vs 8.4 [2.9]×10(8); P<.002 for stromal cell-derived factor-1).

CONCLUSIONS

Younger patients with dilated cardiomiopathy and lower plasma high density lipoprotein levels gain greater benefit from intracoronary cell-therapy. Functional improvement also seems to be enhanced by a lower migratory capacity of the infused cells.

Comparison of transendocardial and intracoronary CD34+ cell transplantation in patients with nonischemic dilated cardiomyopathy

BACKGROUND

In an open-label blinded study, we compared intracoronary and transendocardial CD34(+) cell transplantation in patients with nonischemic dilated cardiomyopathy.

METHODS AND RESULTS

Of the 40 patients with dilated cardiomyopathy, 20 were randomized to receive intracoronary injection and 20 received transendocardial CD34(+) cell delivery. In both groups, CD34(+) cells were mobilized by filgrastim, collected via apheresis, and labeled with technetium-99m radioisotope for single-photon emission computed tomographic imaging. In the intracoronary group, cells were injected intracoronarily in the artery supplying segments of greater perfusion defect on myocardial perfusion scintigraphy. In the transendocardial group, electroanatomic mapping was used to identify viable but dysfunctional myocardium, and transendocardial cell injections were performed. Nuclear single-photon emission computed tomographic imaging for quantification of myocardial retention was performed 18 hours thereafter. At baseline, groups did not differ in age, sex, left ventricular ejection fraction, or N-terminal pro-brain natriuretic peptide levels. The number of CD34(+) cells was also comparable (105 ± 31 × 10(6) in the transendocardial group versus 103 ± 27 × 10(6) in the intracoronary group, P=0.62). At 18 hours after procedure, myocardial retention was higher in the transendocardial group (19.2 ± 4.8%) than in the intracoronary group (4.4 ± 1.2%, P<0.01). At 6 months, left ventricular ejection fraction improved more in the transendocardial group (+8.1 ± 4.3%) than in the intracoronary group (+4.2 ± 2.3%, P=0.03). The same pattern was observed for the 6-minute walk test distance (+125 ± 33 m in the transendocardial group versus +86 ± 13 m in the intracoronary group, P=0.03) and N-terminal pro-brain natriuretic peptide (-628 ± 211 versus -315 ± 133 pg/mL, P=0.04).

CONCLUSIONS

In patients with dilated cardiomyopathy, transendocardial CD34(+) cell transplantation is associated with higher myocardial retention rates and greater improvement in ventricular function, N-terminal pro-brain natriuretic peptide, and exercise capacity compared with intracoronary route.

CLINICAL TRIAL REGISTRATION URL

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

Therapeutic application of cardiac stem cells and other cell types

Various researches on regenerative medicine were carried out experimentally, and selected modalities have been introduced to the clinical arena. Meanwhile, the presence of resident stem cells in the heart and their role in physiological cell turnover were demonstrated. So far skeletal myoblasts, bone marrow-derived cells, mesenchymal stromal cells, and resident cardiac cells have been applied for therapeutic myocardial regeneration. Among them, autologous transplantation of c-kit-positive cardiac stem cells in congestive heart failure patients resulted in an outstanding outcome, with long-lasting beneficial effects without major adverse events. By reviewing these clinical trials, an endeavor was made to seek for an ideal cellular therapy for cardiovascular diseases.

In Situ Electrostimulation Drives a Regenerative Shift in the Zone of Infarcted Myocardium

Electrostimulation represents a well-known trophic factor for different tissues. In vitro electrostimulation of non-stem and stem cells induces myogenic predifferentiation and may be a powerful tool to generate cells with the capacity to respond to local areas of injury. We evaluated the effects of in vivo electrostimulation on infarcted myocardium using a miniaturized multiparameter implantable stimulator in rats. Parameters of electrostimulation were organized to avoid a direct driving or pacing of native heart rhythm. Electrical stimuli were delivered for 14 days across the scar site. In situ electrostimulation used as a cell-free, cytokine-free stimulation system, improved myocardial function, and increased angiogenesis through endothelial progenitor cell migration and production of vascular endothelial growth factor (VEGF). In situ electrostimulation represents a novel means to stimulate repair of the heart and other organs, as well as to precondition tissues for treatment with cell-based therapies.