Electroanatomic Properties of the Myocardium Predict Response to CD34+ Cell Therapy in Patients With Ischemic and Nonischemic Heart Failure

TNF-α Predicts Endothelial Function and Number of CD34+ Cells after Stimulation with G-CSF in Patients with Advanced Heart Failure

Patients with advanced heart failure (HF) have reduced cardiac output and impaired peripheral blood flow, which diminishes endothelial shear stress and consequently flow-mediated dilatation (FMD). The aim of our study was to find out whether endothelial dysfunction is associated with the number of CD34+ cells and TNF-α levels in patients with ischemic and non-ischemic HF after stimulation with granulocyte colony-stimulating factor (G-CSF). We included 56 patients with advanced HF (LVEF < 35%). Eighteen patients (32.14%) had ischemic and 38 (67.86%) patients had non-ischemic HF. FMD of the brachial artery was performed before the patients underwent 5-day bone marrow stimulation with daily subcutaneous injections of G-CSF (5 μg/kg bid). On the fifth day peripheral blood CD34+ cell count was measured. No statistically significant differences were found between the patient groups in NT-proBNP levels ((1575 (425−2439) vs. 1273 (225−2239)) pg/mL; p = 0.40), peripheral blood CD34+ cell count ((67.54 ± 102.32 vs. 89.76 ± 71.21) × 106; p = 0.32), TNF-α ((8.72 ± 10.30 vs. 4.96 ± 6.16) ng/mL; p = 0.13) and FMD (6.7 ± 5.4 vs. 7.2 ± 5.9%; p = 0.76). In a linear regression model, only FMD (p = 0.001) and TNF-α (p = 0.003) emerged as statistically significant predictors of CD34+ cells counts. Our study suggests that TNF-α is a good predictor of impaired endothelial function and of CD34+ cells mobilization after G-CSF stimulation in patients with advanced HF of ischemic and non-ischemic origin.

A PILOT CLINICAL TRIAL OF CELL THERAPY IN HEART FAILURE WITH PRESERVED EJECTION FRACTION

Aims

We investigated the effects of CD34⁺ cell therapy in patients with heart failure with preserved ejection fraction (HFpEF).

Methods and results

In a prospective pilot study, we enrolled 30 patients with HFpEF. In Phase 1, patients were treated with medical therapy for 6 months. Thereafter, all patients underwent CD34⁺ cell transplantation. Using electroanatomical mapping, we measured local mechanical diastolic delay and myocardial viability to guide the targeting of cell injections. Patients were followed for 6 months after cell transplantation (Phase 2), and the primary endpoint was the difference in change in E/e′ between Phase 1 and Phase 2. In Phase 1, the decrease in E/e′ was significantly less pronounced than in Phase 2 (−0.33 ± 1.72 vs. −3.77 ± 2.66, p = 0.001). During Phase 1, there was no significant change in global systolic strain (GLS; from −12.5 ± 2.4% to −12.8 ± 2.6%, p = 0.77), N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP; from 1463 ± 1247 pg/ml to 1298 ± 931 pg/ml, p = 0.31), or 6‐min walk test (6MWT; from 391 ± 75 m to 402 ± 93 m, p = 0.42). In Phase 2, an improvement was noted in NT‐proBNP (from 1298 ± 931 pg/ml to 887 ± 809 pg/ml, p = 0.02) and 6MWT (from 402 ± 93 m to 438 ± 72 m, p = 0.02). Although GLS did not change significantly in Phase 2 (from −12.8 ± 2.6% to −13.8 ± 2.7%, p = 0.36), we found improved local systolic strain at cell injection sites (−3.4 ± 6.8%, p = 0.005).

Conclusions

In this non‐randomized trial, transendocardial CD34⁺ cell therapy in HFpEF was associated with an improvement in E/e′, NT‐proBNP, exercise capacity, and local myocardial strain at the cell injection sites.

Clinical Trial Registration: ClinicalTrials.gov NCT02923609.

Transendocardial CD34+ Cell Therapy Improves Local Mechanical Dyssynchrony in Patients With Nonischemic Dilated Cardiomyopathy

We investigated the effects of cell therapy on local mechanical dyssynchrony (LMD) in patients with nonischemic dilated cardiomyopathy (NICM). We analyzed electromechanical data of 30 NICM patients undergoing CD34⁺ cell transplantation. All patients underwent bone marrow stimulation; CD34⁺ cells were collected by apheresis and injected transendocardially. At baseline and at 6 months after therapy, we performed electromechanical mapping and measured unipolar voltage (UV) and LMD at cell injection sites. LMD was defined as a temporal difference between global and segmental peak systolic displacement normalized to the average duration of the RR interval. Favorable clinical response was defined as increase in the left ventricular ejection fraction (LVEF) ≥5% between baseline and 6 months. Using paired electromechanical point-by-point analysis, we were able to identify 233 sites of CD34⁺ cell injections in 30 patients. We found no overall differences in local UV between baseline and 6 months (10.7 ± 4.1 mV vs 10.0 ± 3.6 mV, P = 0.42). In contrast, LMD decreased significantly (17 ± 17% at baseline vs 13 ± 12% at 6 months, P = 0.00007). Favorable clinical response at 6 months was found in 19 (63%) patients (group A), and 11 (37%) patients did not respond to cell therapy (group B). At baseline, the two groups did not differ in age, gender, LVEF, or N terminal-pro brain natriuretic peptide (NT-proBNP) levels. Similarly, we found no differences in baseline UV (9.5 ± 2.9 mV in group A vs 8.6 ± 2.4 mV in group B, P = 0.41) or LMD at cell injection sites (17 ± 19% vs 16 ± 14%, P = 0.64). In contrast, at 6 months, we found higher UV in group A (10.0 ± 3.1 mV vs 7.4 ± 1.9 mV in group B, P = 0.04). Furthermore, when compared with group B, patients in group A displayed a significantly lower LMD (11 ± 12% vs 16 ± 10%, P = 0.002). Thus, it appears that favorable clinical effects of cell therapy in NICM patients may be associated with a decrease of LMD at cell injection sites.

Correlation between electromechanical parameters (NOGA XP) and changes of myocardial ischemia in patients with refractory angina

INTRODUCTION

Cell therapy has the potential to improve symptoms and clinical outcomes in refractory angina (RFA). Further analyses are needed to evaluate factors influencing its therapeutic effectiveness.

AIM

Assessment of electromechanical (EM) parameters of the left ventricle (LV) and investigation of correlation between EM parameters of the myocardium and response to CD133+ cell therapy.

MATERIAL AND METHODS

Thirty patients with RFA (16 active and 14 placebo individuals) enrolled in the REGENT-VSEL trial underwent EM evaluation of the LV with intracardiac mapping system. The following parameters were analyzed: unipolar voltage (UV), bipolar voltage (BV), local linear shortening (LLS). Myocardial ischemia was evaluated with single-photon emission computed tomography (SPECT). The median value of each EM parameter was used for intra-group comparisons.

RESULTS

Global EM parameters (UV, BV, LLS) of LV in active and placebo groups were 11.28 mV, 3.58 mV, 11.12%, respectively; 13.00 mV, 3.81 mV, 11.32%, respectively. EM characteristics analyzed at global and segmental levels did not predict response to CD133+ cell therapy in patients with RFA (Global UV, BV and LLS at rest R = -0.06; R = 0.2; R = -0.1 and at stress: R = 0.07, R = 0.09, R = -0.1, respectively; Segmental UV, BV, LLS at rest R = -0.2, R = 0.03, R = -0.4 and at stress R = 0.02, R = 0.2, R = -0.2, respectively). Multiple linear regression of the treated segments showed that only pre-injection SPECT levels were significantly correlated with post-injection SPECT, either at rest or stress (p < 0.05).

CONCLUSIONS

Electromechanical characteristics of the left ventricle do not predict changes of myocardial perfusion by SPECT after cell therapy. Baseline SPECT results are only predictors of changes of myocardial ischemia observed at 4-month follow-up.

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 Therapy in Patients with Heart Failure: A Comprehensive Review and Emerging Concepts

This review summarizes the results of clinical trials of cell therapy in patients with heart failure (HF). In contrast to acute myocardial infarction (where results have been consistently negative for more than a decade), in the setting of HF the results of Phase I–II trials are encouraging, both in ischaemic and non-ischaemic cardiomyopathy. Several well-designed Phase II studies have met their primary endpoint and demonstrated an efficacy signal, which is remarkable considering that only one dose of cells was used. That an efficacy signal was seen 6–12 months after a single treatment provides a rationale for larger, rigorous trials. Importantly, no safety concerns have emerged. Amongst the various cell types tested, mesenchymal stromal cells derived from bone marrow (BM), umbilical cord, or adipose tissue show the greatest promise. In contrast, embryonic stem cells are not likely to become a clinical therapy. Unfractionated BM cells and cardiosphere-derived cells have been abandoned. The cell products used for HF will most likely be allogeneic. New approaches, such as repeated cell treatment and intravenous delivery, may revolutionize the field. As is the case for most new therapies, the development of cell therapies for HF has been slow, plagued by multifarious problems, and punctuated by many setbacks; at present, the utility of cell therapy in HF remains to be determined. What the field needs is rigorous, well-designed Phase III trials. The most important things to move forward are to keep an open mind, avoid preconceived notions, and let ourselves be guided by the evidence.

Larger End-Diastolic Volume Associates With Response to Cell Therapy in Patients With Nonischemic Dilated Cardiomyopathy

OBJECTIVE

To investigate the association of left ventricular end-diastolic volume (LVEDV) and the response to cell therapy in patients with nonischemic dilated cardiomyopathy (NICM).

PATIENTS AND METHODS

Five-year registry data from 133 consecutive patients with NICM who underwent CD34⁺ cell treatment were analyzed. All patients received granulocyte-colony stimulating factor; CD34⁺ cells were collected by apheresis and delivered by transendocardial injections. Patients with baseline LVEDV less than 200 mL (group A; n=72) and patients with LVEDV 200 to 370 mL (group B; n=54) were included. Patients with LVEDV greater than 370 mL were excluded (n=7). Favorable ejection fraction response was pre-defined by improvement in left ventricular ejection fraction (LVEF) greater than or equal to 5% at 1 y post-cell therapy.

RESULTS

At baseline, groups A and B were comparable with regards to age (52±11 y in group A vs 53±10 y in group B; P=.95), sex (male: 79% vs 83%, respectively; P=.55), creatinine (1.07±0.28 mg/dL vs 1.03±0.21 mg/dL, respectively; P=.21), or N-terminal probrain natriuretic peptide (1454±1658 pg/mL vs 1589±1338 pg/mL, respectively; P=.80). Baseline LVEF was higher in group A (32.8±8.7%) than in group B (30.2±8.7%; P=.03). During follow-up, there were four deaths in group A (5.6%), and 2 in group B (3.7%, P=.63). At 1-year post-cell therapy, LVEDV decreased significantly in group B (-56±30 mL; P=.003), but not in group A (+12±97 mL; P=.13). On multivariate analysis, baseline LVEDV was an independent correlate of favorable response in LVEF to therapy (P=.02).

CONCLUSION

Larger LVEDV was associated with more pronounced increase in LVEF after transendocardial CD34⁺ cell therapy in NICM patients, informing target individuals with the highest likelihood of regenerative response.

TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT02445534.

Favorable Response to CD34+ Cell Therapy Is Associated with a Decrease of Galectin-3 Levels in Patients with Chronic Heart Failure

Background

Galectin-3 plasma levels (gal-3) were shown to correlate with the scar burden in chronic heart failure (CHF) setting. As scar burden predicts response to stem cell therapy, we sought to explore a correlation between gal-3 and response to CD34+ cell transplantation in patients with CHF.

Methods

We performed a post hoc analysis of patients, enrolled in 2 prospective trials investigating the clinical effects of CD34+ cell therapy in patients with ischemic cardiomyopathy (ICMP) and nonischemic dilated cardiomyopathy (DCMP). CD34+ cells were mobilized by G-CSF, collected via apheresis, and injected transendocardially using NOGA system. Patients were followed for 3 months and demographic, echocardiographic, and biochemical parameters and gal-3 were analyzed at baseline and at follow-up. Response to cell therapy was defined as an LVEF increase of ≥5%.

Results

61 patients were included in the analysis. The mean age of patients was 52 years and 83% were male. DCMP and ICMP were present in 69% and 31% of patients, respectively. The average serum creatinine was 86 ± 23 μmol/L, NT-proBNP 1132 (IQR 350-2279) pg/mL, and LVEF 30 ± 6%. Gal-3 at baseline and at 3 months did not differ significantly (13.4 ± 5.5 ng/mL vs. 13.1 ± 5.8 ng/mL; p = 0.72), and there were no differences in baseline gal-3 with respect to heart failure etiology (15.1 ± 7.2 ng/mL in ICMP vs. 12.7 ± 4.3 ng/mL in DCMP; p = 0.12). Comparing responders (N = 49) to nonresponders (N = 18), we found no differences in baseline gal-3 (13.6 ± 5.7 ng/mL vs. 13.2 ± 4.9 ng/mL; p = 0.80). However, responders had significantly lower gal-3 at 3-month follow-up (12.1 ± 4.0 ng/mL vs. 15.7 ± 8.4 ng/mL; p < 0.05). Also, responders demonstrated a significant decrease in gal-3 over 3 months, while in nonresponders, an increase in gal-3 occurred (−1.5 ± 5.4 ng/mL vs. +2.7 ± 4.3 ng/mL; p = 0.01).

Conclusions

In patients with chronic heart failure undergoing CD34+ cell therapy, a decrease in galectin-3 plasma levels is associated with beneficial response to this treatment modality. Further prospective data is warranted to confirm our findings and to deepen our understanding of the role of gal-3 in the field of stem cell therapy.

Clinical Trial Design for Investigational Cardio-Regenerative Therapy

Human trials of cardio-regenerative biologic therapies are being performed worldwide to address a growing, unmet need for durable treatments of cardiovascular disease. A well-constructed clinical trial design for these novel therapies requires careful attention to defining a clear hypothesis, a patient population, and anticipated outcomes. The scope of screening, method of randomization, blinding approach, data monitoring, and statistical analysis plan are the foundational elements that must be addressed in any clinical trial. Although the experience of human trials involving extracellular matrix constructs for cardiovascular disease treatment is limited, numerous lessons have been learned in the field of cell therapy that are translatable across all biologic treatment options. Future progress in this field may include testing combinations of cells, gene-transfer agents, and matrix and identifying treatment responders versus nonresponders.