Intramyocardial autologous cell engraftment in patients with ischaemic heart failure: a meta-analysis of randomised controlled trials

Meta-Analysis of Percutaneous Endomyocardial Cell Therapy in Patients with Ischemic Heart Failure by Combination of Individual Patient Data (IPD) of ACCRUE and Publication-Based Aggregate Data

Individual patient data (IPD)-based meta-analysis (ACCRUE, meta-analysis of cell-based cardiac studies, NCT01098591) revealed an insufficient effect of intracoronary cell-based therapy in acute myocardial infarction. Patients with ischemic heart failure (iHF) have been treated with reparative cells using percutaneous endocardial, surgical, transvenous or intracoronary cell delivery methods, with variable effects in small randomized or cohort studies. The objective of this meta-analysis was to investigate the safety and efficacy of percutaneous transendocardial cell therapy in patients with iHF. Two investigators extracted the data. Individual patient data (IPD) (n = 8 studies) and publication-based (n = 10 studies) aggregate data were combined for the meta-analysis, including patients (n = 1715) with chronic iHF. The data are reported in accordance with PRISMA guidelines. The primary safety and efficacy endpoints were all-cause mortality and changes in global ejection fraction. The secondary safety and efficacy endpoints were major adverse events, hospitalization and changes in end-diastolic and end-systolic volumes. Post hoc analyses were performed using the IPD of eight studies to find predictive factors for treatment safety and efficacy. Cell therapy was significantly (p < 0.001) in favor of survival, major adverse events and hospitalization during follow-up. A forest plot analysis showed that cell therapy presents a significant benefit of increasing ejection fraction with a mean change of 2.51% (95% CI: 0.48; 4.54) between groups and of significantly decreasing end-systolic volume. The analysis of IPD data showed an improvement in the NYHA and CCS classes. Cell therapy significantly decreased the end-systolic volume in male patients; in patients with diabetes mellitus, hypertension or hyperlipidemia; and in those with previous myocardial infarction and baseline ejection fraction ≤ 45%. The catheter-based transendocardial delivery of regenerative cells proved to be safe and effective for improving mortality and cardiac performance. The greatest benefit was observed in male patients with significant atherosclerotic co-morbidities.

Impact of procedural variability and study design quality on the efficacy of cell-based therapies for heart failure - a meta-analysis

BACKGROUND

Cell-based therapy has long been considered a promising strategy for the treatment of heart failure (HF). However, its effectiveness in the clinical setting is now doubted. Because previous meta-analyses provided conflicting results, we sought to review all available data focusing on cell type and trial design.

METHODS AND FINDINGS

The electronic databases PubMed, Cochrane library, ClinicalTrials.gov, and EudraCT were searched for randomized controlled trials (RCTs) utilizing cell therapy for HF patients from January 1, 2000 to December 31, 2020. Forty-three RCTs with 2855 participants were identified. The quality of the reported study design was assessed by evaluating the risk-of-bias (ROB). Primary outcomes were defined as mortality rate and left ventricular ejection fraction (LVEF) change from baseline. Secondary outcomes included both heart function data and clinical symptoms/events. Between-study heterogeneity was assessed using the I2 index. Subgroup analysis was performed based on HF type, cell source, cell origin, cell type, cell processing, type of surgical intervention, cell delivery routes, cell dose, and follow-up duration. Only 10 of the 43 studies had a low ROB for all method- and outcome parameters. A higher ROB was associated with a greater increase in LVEF. Overall, there was no impact on mortality for up to 12 months follow-up, and a clinically irrelevant average LVEF increase by LVEF (2.4%, 95% CI = 0.75-4.05, p = 0.004). Freshly isolated, primary cells tended to produce better outcomes than cultured cell products, but there was no clear impact of the cell source tissue, bone marrow cell phenotype or cell chricdose (raw or normalized for CD34+ cells). A meaningful increase in LVEF was only observed when cell therapy was combined with myocardial revascularization.

CONCLUSIONS

The published results suggest a small increase in LVEF following cell therapy for heart failure, but publication bias and methodologic shortcomings need to be taken into account. Given that cardiac cell therapy has now been pursued for 20 years without real progress, further efforts should not be made.

STUDY REGISTRY NUMBER

This meta-analysis is registered at the international prospective register of systematic reviews, number CRD42019118872.

Epicardial Transplantation of Autologous Cardiac Micrografts During Coronary Artery Bypass Surgery

Background: Cardio-regenerative cell therapies offer additional biologic support to coronary artery bypass surgery (CABG) and are aimed at functionally repairing the myocardium that suffers from or is damaged by ischemia. This non-randomized open-label study assessed the safety and feasibility of epicardial transplantation of atrial appendage micrografts (AAMs) in patients undergoing CABG surgery. Methods: Twelve consecutive patients destined for CABG surgery were included in the study. Six patients received AAMs during their operation and six patients were CABG-operated without AAMs transplantation. Data from 30 elective CABG patients was collected for a center- and time-matched control group. The AAMs were processed during the operation from a biopsy collected from the right atrial appendage. They were delivered epicardially onto the infarct scar site identified in preoperative late gadolinium enhancement cardiac magnetic resonance imaging (CMRI). The primary outcome measures at the 6-month follow-up were (i) patient safety in terms of hemodynamic and cardiac function over time and (ii) feasibility of therapy administration in a clinical setting. Secondary outcome measures were left ventricular wall thickness, change in myocardial scar tissue volume, changes in left ventricular ejection fraction, plasma concentrations of N-terminal pro-B-type natriuretic peptide levels, NYHA class, number of days in hospital and changes in the quality of life. Results: Epicardial transplantation of AAMs was safe and feasible to be performed during CABG surgery. CMRI demonstrated an increase in viable cardiac tissue at the infarct site in patients receiving AAMs treatment. Conclusions and Relevance: Transplantation of AAMs shows good clinical applicability as performed during cardiac surgery, shows initial therapeutic effect on the myocardium and has the potential to serve as a delivery platform for cardiac gene therapies. Trial Registration:ClinicalTrials.gov, identifier: NCT02672163.

Meta-Analysis of Cell Therapy Studies in Heart Failure and Acute Myocardial Infarction

Heart failure (HF) is one of the leading causes of death worldwide and has reached epidemic proportions in most industrialized nations. Despite major improvements in the treatment and management of the disease, the prognosis for patients with HF remains poor with approximately only half of patients surviving for 5 years or longer after diagnosis. The poor prognosis of HF patients is in part because of irreparable damage to cardiac tissue and concomitant maladaptive changes associated with the disease. Cell-based therapies may have the potential to transform the treatment and prognosis of HF through regeneration or repair of damaged cardiac tissue. Accordingly, numerous phase I and II randomized clinical trials have tested the clinical benefits of cell transplant, mostly autologous bone marrow-derived mononuclear cells, in patients with HF, ischemic heart disease, and acute myocardial infarction. Although many of these trials were relatively small, meta-analyses of cell-based therapies have attempted to apply rigorous statistical methodology to assess the potential clinical benefits of the intervention. As a prelude to larger phase III trials, meta-analyses, therefore, remain the obvious means of evaluating the available clinical evidence. Here, we review the different meta-analyses of randomized clinical trials that evaluate the safety and potential beneficial effect of cell therapies in HF and acute myocardial infarction spanning nearly 2 decades since the first pioneering trials were conducted.

Effect of stem cell transplantation on patients with ischemic heart failure: a systematic review and meta-analysis of randomized controlled trials

Stem cell transplantation (SCT) has become a promising way to treat ischemic heart failure (IHF). We performed a large-scale meta-analysis of randomized clinical trials to investigate the efficacy and safety of SCT in IHF patients. Randomized controlled trials (RCTs) involving stem cell transplantation for the treatment of IHF were identified by searching the PubMed, EMBASE, SpringerLink, Web of Science, and Cochrane Systematic Review databases as well as from reviews and the reference lists of relevant articles. Fourteen eligible randomized controlled trials were included in this study, for a total of 669 IHF patients, of which 380 patients were treated with SCT. The weighted mean difference (WMD) was calculated for changes in the New York Heart Association (NYHA) class, left ventricular ejection fraction (LVEF), left ventricular end-diastolic and end-systolic volumes (LVEDV and LVESV), and Canadian Cardiovascular Society (CCS) angina grade using a fixed effects model, while relative risk (RR) was used for mortality. Compared with the control group, SCT significantly lowered the NYHA class (MD = − 0.73, 95% CI − 1.32 to − 0.14, P < 0.05), LVESV (MD = − 14.80, 95% CI − 20.88 to − 8.73, P < 0.05), and CCS grade (MD = − 0.81, 95% CI − 1.45 to − 0.17, P < 0.05). Additionally, SCT increased LVEF (MD = 6.55, 95% CI 5.93 to 7.16, P < 0.05). However, LVEDV (MD = − 0.33, 95% CI − 1.09 to 0.44, P > 0.05) and mortality (RR = 0.86, 95% CI 0.45 to 1.66, P > 0.05) did not differ between the two groups. This meta-analysis suggests that SCT may contribute to the improvement of LVEF, as well as the reduction of the NYHA class, CCS grade, and LVESV. In addition, SCT does not affect mortality.

The use of stem cells in ischemic heart disease treatment

Ischemic heart disease is a major cause of death and disabilities worldwide. Unfortunately, not all patients are suitable for direct revascularization. Cell-based therapies may be alternative options because of their potential to promote neovascularisation and endothelial repair, improving myocardial perfusion. The success of cell-based therapies depends on the type of implanted stem cells, delivery method and underlying disease. Several different cell populations including bone marrow-derived mononuclear cells (MNCs), mesenchymal stromal cells (MSCs), CD34+, CD133+, endothelial progenitor cells, adipose-derived mesenchymal stromal cells (ASCs) and stem cells from placenta and umbilical cord have been investigated. Presently, no consensus exists about the best cell type for clinical regenerative therapy. Because the system of coronary arteries in the ischemic area is poor and most of the coronary artery is significantly narrowed or closed, direct implantation of stem cells in the ischemic area of the heart muscle appears an attractive method.

Amorphous polyphosphate, a smart bioinspired nano-/bio-material for bone and cartilage regeneration: towards a new paradigm in tissue engineering

Physiological amorphous polyphosphate nano/micro-particles, injectable and implantable, attract and stimulate MSCs into implants for tissue regeneration.

Pursuing meaningful end-points for stem cell therapy assessment in ischemic cardiac disease

Despite optimal interventional and medical therapy, ischemic heart disease is still an important cause of morbidity and mortality worldwide. Although not included in standard of care rehabilitation, stem cell therapy (SCT) could be a solution for prompting cardiac regeneration. Multiple studies have been published from the beginning of SCT until now, but overall no unanimous conclusion could be drawn in part due to the lack of appropriate end-points. In order to appreciate the impact of SCT, multiple markers from different categories should be considered: Structural, biological, functional, physiological, but also major adverse cardiac events or quality of life. Imaging end-points are among the most used - especially left ventricle ejection fraction (LVEF) measured through different methods. Other imaging parameters are infarct size, myocardial viability and perfusion. The impact of SCT on all of the aforementioned end-points is controversial and debatable. 2D-echocardiography is widely exploited, but new approaches such as tissue Doppler, strain/strain rate or 3D-echocardiography are more accurate, especially since the latter one is comparable with the MRI gold standard estimation of LVEF. Apart from the objective parameters, there are also patient-centered evaluations to reveal the benefits of SCT, such as quality of life and performance status, the most valuable from the patient point of view. Emerging parameters investigating molecular pathways such as non-coding RNAs or inflammation cytokines have a high potential as prognostic factors. Due to the disadvantages of current techniques, new imaging methods with labelled cells tracked along their lifetime seem promising, but until now only pre-clinical trials have been conducted in humans. Overall, SCT is characterized by high heterogeneity not only in preparation, administration and type of cells, but also in quantification of therapy effects.

Epicardial delivery of autologous atrial appendage micrografts during coronary artery bypass surgery-safety and feasibility study

Background

The atrial appendages are a tissue reservoir for cardiac stem cells. During on-pump coronary artery bypass graft (CABG) surgery, part of the right atrial appendage can be excised upon insertion of the right atrial cannula of the heart-lung machine. In the operating room, the removed tissue can be easily cut into micrografts for transplantation. This trial aims to assess the safety and feasibility of epicardial transplantation of atrial appendage micrografts in patients undergoing CABG surgery.

Methods/design

Autologous cardiac micrografts are made from leftover right atrial appendage during CABG of 6 patients. Atrial appendage is mechanically processed to micrografts consisting of atrial appendage-derived cells (AADCs) and their extracellular matrix (ECM). The micrografts are epicardially transplanted in a fibrin gel and covered with a tissue-engineered ECM sheet. Parameters including echocardiography—reflecting cardiac insufficiency—are studied pre- and post-operatively as well as at 3 and 6 months of the follow-up. Cardiac functional magnetic resonance imaging is performed preoperatively and at 6-month follow-up. The primary outcome measures are patient safety in terms of hemodynamic and cardiac function over time and feasibility of therapy administration in a clinical setting. Secondary outcome measures are left ventricular wall thickness, change in the amount of myocardial scar tissue, changes in left ventricular ejection fraction, plasma concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, New York Heart Association class, days in hospital, and changes in the quality of life. Twenty patients undergoing routine CAGB surgery will be recruited to serve as a control group.

Discussion

This study aims to address the surgical feasibility and patient safety of epicardially delivered atrial appendage micrografts during CABG surgery. Delivery of autologous micrografts and AADCs has potential applications for cell and cell-based gene therapies.

Trial registration

ClinicalTrials.gov Identifier: NCT02672163. Date of registration: 02.02.2016

Pathophysiological aldosterone levels modify the secretory activity of cardiac progenitor cells

Cardiac progenitor cells (CPCs) trigger regenerative processes via paracrine mechanisms in response to changes in their environment. In the present study we explored alterations in the secretory activity of CPCs induced by raised aldosterone levels symptomatic for heart failure. The cytokine profile of the supernatant of CPCs that were treated with the mineralocorticoid showed an induction of interleukin-6 secretion. Mass spectrometric analyses revealed an increase in the abundance of secreted proteins associated with regeneration and cell migration like gelsolin and galectin-1. Differential regulation of proteins associated with the extracellular matrix further points to an activation of cell migration. In response to supernatant, migration and proliferation were induced in CPCs, indicating a potential role of paracrine factors in the activation of CPCs from other regions of the heart or extra-cardiac sources. Changes in the secretory activity of CPCs might aim to compensate for the detrimental actions of aldosterone in heart failure.

Coronary revascularization in the elderly with stable angina

A proportion of elderly with coronary artery disease is rapidly growing. They have more severe coronary artery disease, therefore, derive more benefit from revascularization and have a greater need for it. The elderly is a heterogeneous group, but compared to the younger cohort, the choice of the optimal revascularization method is much more complicated among them. In recent decades, results has improved dramatically both in surgery and percutaneous coronary intervention (PCI), even in very old persons. Despite the lack of evidence in elderly, it is obvious, that coronary artery bypass surgery (CABG) has a more pronounced effect on long-term survival in price of more strokes, while PCI is certainly less invasive. Age itself is not a criterion for the selection of treatment strategy, but the elderly are often more interested in quality of life and personal independence instead of longevity. This article discusses the factors that influence the choice of the revascularization method in the elderly with stable angina and presents a complex algorithm for making an individual risk-benefit profile. As a consequence the features of CABG and PCI in elderly patients are exposed. Emphasis is centered on the frailty and non-medical factors, including psychosocial, as essential components in making the decision of what strategy to choose. Good communication with the patients and giving them unbiased information is encouraged.

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

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

Ultrasound-guided transthoracic intramyocardial injection in mice

Murine models of cardiovascular disease are important for investigating pathophysiological mechanisms and exploring potential regenerative therapies. Experiments involving myocardial injection are currently performed by direct surgical access through a thoracotomy. While convenient when performed at the time of another experimental manipulation such as coronary artery ligation, the need for an invasive procedure for intramyocardial delivery limits potential experimental designs. With ever improving ultrasound resolution and advanced noninvasive imaging modalities, it is now feasible to routinely perform ultrasound-guided, percutaneous intramyocardial injection. This modality efficiently and reliably delivers agents to a targeted region of myocardium. Advantages of this technique include the avoidance of surgical morbidity, the facility to target regions of myocardium selectively under ultrasound guidance, and the opportunity to deliver injectate to the myocardium at multiple, predetermined time intervals. With practiced technique, complications from intramyocardial injection are rare, and mice quickly return to normal activity on recovery from anesthetic. Following the steps outlined in this protocol, the operator with basic echocardiography experience can quickly become competent in this versatile, minimally invasive technique.

Preparing the ground for tissue regeneration: from mechanism to therapy

Chronic diseases confer tissue and organ damage that reduce quality of life and are largely refractory to therapy. Although stem cells hold promise for treating degenerative diseases by 'seeding' injured tissues, the regenerative capacity of stem cells is influenced by regulatory networks orchestrated by local immune responses to tissue damage, with macrophages being a central component of the injury response and coordinator of tissue repair. Recent research has turned to how cellular and signaling components of the local stromal microenvironment (the 'soil' to the stem cells' seed), such as local inflammatory reactions, contribute to successful tissue regeneration. This Review discusses the basic principles of tissue regeneration and the central role locally acting components may play in the process. Application of seed-and-soil concepts to regenerative medicine strengthens prospects for developing cell-based therapies or for promotion of endogenous repair.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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