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

Stem cell therapy for dilated cardiomyopathy

BACKGROUND

Stem cell therapy (SCT) has been proposed as an alternative treatment for dilated cardiomyopathy (DCM), nonetheless its effectiveness remains debatable.

OBJECTIVES

To assess the effectiveness and safety of SCT in adults with non-ischaemic DCM.

SEARCH METHODS

We searched CENTRAL in the Cochrane Library, MEDLINE, and Embase for relevant trials in November 2020. We also searched two clinical trials registers in May 2020.

SELECTION CRITERIA

Eligible studies were randomized controlled trials (RCT) comparing stem/progenitor cells with no cells in adults with non-ischaemic DCM. We included co-interventions such as the administration of stem cell mobilizing agents. Studies were classified and analysed into three categories according to the comparison intervention, which consisted of no intervention/placebo, cell mobilization with cytokines, or a different mode of SCT. The first two comparisons (no cells in the control group) served to assess the efficacy of SCT while the third (different mode of SCT) served to complement the review with information about safety and other information of potential utility for a better understanding of the effects of SCT.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all references for eligibility, assessed trial quality, and extracted data. We undertook a quantitative evaluation of data using random-effects meta-analyses. We evaluated heterogeneity using the I² statistic. We could not explore potential effect modifiers through subgroup analyses as they were deemed uninformative due to the scarce number of trials available. We assessed the certainty of the evidence using the GRADE approach. We created summary of findings tables using GRADEpro GDT. We focused our summary of findings on all-cause mortality, safety, health-related quality of life (HRQoL), performance status, and major adverse cardiovascular events.

MAIN RESULTS

We included 13 RCTs involving 762 participants (452 cell therapy and 310 controls). Only one study was at low risk of bias in all domains. There were many shortcomings in the publications that did not allow a precise assessment of the risk of bias in many domains. Due to the nature of the intervention, the main source of potential bias was lack of blinding of participants (performance bias). Frequently, the format of the continuous data available was not ideal for use in the meta-analysis and forced us to seek strategies for transforming data in a usable format. We are uncertain whether SCT reduces all-cause mortality in people with DCM compared to no intervention/placebo (mean follow-up 12 months) (risk ratio (RR) 0.84, 95% confidence interval (CI) 0.54 to 1.31; I² = 0%; studies = 7, participants = 361; very low-certainty evidence). We are uncertain whether SCT increases the risk of procedural complications associated with cells injection in people with DCM (data could not be pooled; studies = 7; participants = 361; very low-certainty evidence). We are uncertain whether SCT improves HRQoL (standardized mean difference (SMD) 0.62, 95% CI 0.01 to 1.23; I² = 72%; studies = 5, participants = 272; very low-certainty evidence) and functional capacity (6-minute walk test) (mean difference (MD) 70.12 m, 95% CI -5.28 to 145.51; I² = 87%; studies = 5, participants = 230; very low-certainty evidence). SCT may result in a slight functional class (New York Heart Association) improvement (data could not be pooled; studies = 6, participants = 398; low-certainty evidence). None of the included studies reported major adverse cardiovascular events as defined in our protocol. SCT may not increase the risk of ventricular arrhythmia (data could not be pooled; studies = 8, participants = 504; low-certainty evidence). When comparing SCT to cell mobilization with granulocyte-colony stimulating factor (G-CSF), we are uncertain whether SCT reduces all-cause mortality (RR 0.46, 95% CI 0.16 to 1.31; I² = 39%; studies = 3, participants = 195; very low-certainty evidence). We are uncertain whether SCT increases the risk of procedural complications associated with cells injection (studies = 1, participants = 60; very low-certainty evidence). SCT may not improve HRQoL (MD 4.61 points, 95% CI -5.62 to 14.83; studies = 1, participants = 22; low-certainty evidence). SCT may improve functional capacity (6-minute walk test) (MD 140.14 m, 95% CI 119.51 to 160.77; I² = 0%; studies = 2, participants = 155; low-certainty evidence). None of the included studies reported MACE as defined in our protocol or ventricular arrhythmia. The most commonly reported outcomes across studies were based on physiological measures of cardiac function where there were some beneficial effects suggesting potential benefits of SCT in people with non-ischaemic DCM. However, it is unclear if this intermediate effects translates into clinical benefits for these patients. With regard to specific aspects related to the modality of cell therapy and its delivery, uncertainties remain as subgroup analyses could not be performed as planned, making it necessary to wait for the publication of several studies that are currently in progress before any firm conclusion can be reached.

AUTHORS' CONCLUSIONS

We are uncertain whether SCT in people with DCM reduces the risk of all-cause mortality and procedural complications, improves HRQoL, and performance status (exercise capacity). SCT may improve functional class (NYHA), compared to usual care (no cells). Similarly, when compared to G-CSF, we are also uncertain whether SCT in people with DCM reduces the risk of all-cause mortality although some studies within this comparison observed a favourable effect that should be interpreted with caution. SCT may not improve HRQoL but may improve to some extent performance status (exercise capacity). Very low-quality evidence reflects uncertainty regarding procedural complications. These suggested beneficial effects of SCT, although uncertain due to the very low certainty of the evidence, are accompanied by favourable effects on some physiological measures of cardiac function. Presently, the most effective mode of administration of SCT and the population that could benefit the most is unclear. Therefore, it seems reasonable that use of SCT in people with DCM is limited to clinical research settings. Results of ongoing studies are likely to modify these conclusions.

Cell-Based Therapies for Heart Failure

Heart failure has reached epidemic proportions with the advances in cardiovascular therapies for ischemic heart diseases and the progressive aging of the world population. Efficient pharmacological therapies are available for treating heart failure, but unfortunately, even with optimized therapy, prognosis is often poor. Their last therapeutic option is, therefore, a heart transplantation with limited organ supply and complications related to immunosuppression. In this setting, cell therapies have emerged as an alternative. Many clinical trials have now been performed using different cell types and injection routes. In this perspective, we will analyze the results of such trials and discuss future perspectives for cell therapies as an efficacious treatment of heart failure.

Efficacy and safety of stem cell therapy in patients with dilated cardiomyopathy: a systematic appraisal and meta-analysis

Background

The clinical significance of stem cell therapy in the treatment of dilated cardiomyopathy remains unclear. This systemic appraisal and meta-analysis aimed to assess the efficacy and safety of stem cell therapy in patients with dilated cardiomyopathy. After searching the PubMed, Embase, and Cochrane library databases until November 2017, we conducted a meta-analysis to evaluate the efficacy and safety of stem cell therapy in patients with dilated cardiomyopathy.

Methods

The weighted mean difference (WMD), standard mean difference (SMD), relative risk (RR), and 95% confidence interval (CI) were summarized in this meta-analysis. Both fixed effects and random effects models were used to combine the data. Sensitivity analyses were conducted to evaluate the impact of an individual dataset on the pooled results.

Results

A total of eight randomized controlled trials, which involved 531 participants, met the inclusion criteria in this systematic appraisal and meta-analysis. Our meta-analysis showed that stem cell therapy improves left ventricular ejection fraction (SMD = 1.09, 95% CI 0.29 to 1.90, I² = 92%) and reduces left ventricular end-systolic volume (SMD = − 0.36, 95% CI − 0.61 to − 0.10, I² = 20.5%) and left ventricular end-diastolic chamber size (SMD = − 0.48, 95% CI − 0.89 to − 0.07, I² = 64.8%) in patients with dilated cardiomyopathy. However, stem cell therapy has no effect on mortality (RR = 0.72, 95% CI 0.50 to 1.02, I² = 30.2%) and 6-min-walk test (WMD = 51.52, 95% CI − 24.52 to 127.55, I² = 94.8%).

Conclusions

This meta-analysis suggests that stem cell therapy improves left ventricular ejection fraction and reduces left ventricular end-systolic volume and left ventricular end-diastolic chamber size in patients with dilated cardiomyopathy. However, future well-designed large studies might be necessary to clarify the effect of stem cell therapy in patients with dilated cardiomyopathy.

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.

Safety and efficacy of bone marrow-derived cells therapy on cardiomyopathy: a meta-analysis

BACKGROUND

Controversial results still existed on the clinical utility of bone marrow-derived cells (BMCs) for cardiomyopathy (CMP). This study aims to reveal the true power of this promising approach by synthesizing all the available data on this subject matter.

METHODS

Twenty studies including 1418 patients were identified from systematic search. Weighted mean differences for changes in left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), 6-min walk distance, and NYHA functional class were estimated with a random-effects model. Major adverse cardiovascular event (MACE), rehospitalization, all-cause mortality, and patients' quality of life were also calculated.

RESULTS

Compared with the control group, BMC therapy resulted in greater LVEF (3.72%, 95% CI 2.31 to 5.13, P < 0.0001), 6-min walk distance (53.16, 95% CI 25.17 to 81.10, P = 0.0002), NYHA functional class (- 0.48, 95% CI - 0.65 to - 0.31, P < 0.0001), and smaller LVESV (- 16.79, 95% CI - 27.21 to - 6.38, P = 0.002). BMC treatment significantly reduced the mortality rate and improved patients' quality of life. No significant difference was found between the BMCs and control group in LVEDV, MACE, and rehospitalization rate. However, the outcomes showed a clear trend in favor of the BMC group. Subgroup analysis showed that LVEF improved greater in a subgroup of intracoronary infusion, BMSC, or higher cell dose.

CONCLUSION

The results of the current meta-analysis suggest that BMC treatment for CMP is safe and feasible. This therapy was associated with persistent improvements in LV function, LV remodeling, functional class, patients' survival, and quality of life. Intracoronary infusion of high-dose (> 10⁸) BMSC might be a better therapeutic option for CMP patients. Further evidences are needed to verify our results.

Regenerative Therapy for Cardiomyopathies

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

A systematic review of randomised controlled trials examining the therapeutic effects of adult bone marrow-derived stem cells for non-ischaemic dilated cardiomyopathy

BACKGROUND

Certain early-phase clinical trials have suggested that bone marrow-derived stem cell transplantation might improve left ventricular function in patients with non-ischaemic dilated cardiomyopathy (NIDCM), whereas others trials have revealed no benefit from this approach. We sought to evaluate the therapeutic effects of bone marrow-derived stem cell therapy on NIDCM.

METHODS

We searched the PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases (through February 2016) for randomised controlled clinical trials that reported on bone marrow-derived stem cell transplantation for patients with NIDCM with a follow-up period ≥12 months. The co-primary endpoints were changes in mortality rate and left ventricular ejection fraction (LVEF); the secondary endpoints were changes in the 6-minute-walk test (6MWT) and left ventricular chamber size. Seven trials involving bone marrow-derived stem cell therapy that included 482 patients satisfied the inclusion and exclusion criteria.

RESULTS

Subjects who received bone marrow-derived stem cell therapy exhibited a significant reduction in mortality rate (19.7% in the cell group vs. 27.1% in the control group; 95% confidence interval (CI) -0.16 to -0.00, I 2 = 52%, p = 0.04). Bone marrow-derived stem cell therapy tended to produce LVEF improvement within 6 months (1.83% increase; 95% CI -0.27 to 3.94, I 2 = 74%, p = 0.09) and significantly improved LVEF after mid-term (6-12 months) follow-up (3.53% increase; 95% CI 0.76 to 6.29, I 2 = 88%, p = 0.01). However, this therapy produced no significant benefit in the 6MWT (p = 0.18). Finally, the transplantation of increased numbers of stem cells resulted in no observable additional benefit with respect to LVEF.

CONCLUSIONS

Bone marrow-derived stem cell therapy might have improved prognoses and appeared to provide moderate benefits in cardiac systolic function at mid-term follow-up. However, this therapy produced no observed improvement in exercise tolerance.

Bone Marrow-Derived Progenitor Cells Are Functionally Impaired in Ischemic Heart Disease

To determine whether the presence of ischemic heart disease (IHD) per se, or rather the co-presence of heart failure (HF), is the primum movens for less effective stem cell products in autologous stem cell therapy, we assessed numbers and function of bone marrow (BM)-derived progenitor cells in patients with coronary artery disease (n = 17), HF due to ischemic cardiomyopathy (n = 8), non-ischemic HF (n = 7), and control subjects (n = 11). Myeloid and erythroid differentiation capacity of BM-derived mononuclear cells was impaired in patients with underlying IHD but not with non-ischemic HF. Migration capacity decreased with increasing IHD severity. Hence, IHD, with or without associated cardiomyopathy, is an important determinant of progenitor cell function. No depletion of hematopoietic and endothelial progenitor cells (EPC) within the BM was observed, while circulating EPC numbers were increased in the presence of IHD, suggesting active recruitment. The observed myelosuppression was not driven by inflammation and thus other mechanisms are at play.