Regenerative Therapy Prevents Heart Failure Progression in Dyssynchronous Nonischemic Narrow QRS Cardiomyopathy

KATP channel dependent heart multiome atlas

Plasmalemmal ATP sensitive potassium (K_ATP) channels are recognized metabolic sensors, yet their cellular reach is less well understood. Here, transgenic Kir6.2 null hearts devoid of the K_ATP channel pore underwent multiomics surveillance and systems interrogation versus wildtype counterparts. Despite maintained organ performance, the knockout proteome deviated beyond a discrete loss of constitutive K_ATP channel subunits. Multidimensional nano-flow liquid chromatography tandem mass spectrometry resolved 111 differentially expressed proteins and their expanded network neighborhood, dominated by metabolic process engagement. Independent multimodal chemometric gas and liquid chromatography mass spectrometry unveiled differential expression of over one quarter of measured metabolites discriminating the Kir6.2 deficient heart metabolome. Supervised class analogy ranking and unsupervised enrichment analysis prioritized nicotinamide adenine dinucleotide (NAD⁺), affirmed by extensive overrepresentation of NAD⁺ associated circuitry. The remodeled metabolome and proteome revealed functional convergence and an integrated signature of disease susceptibility. Deciphered cardiac patterns were traceable in the corresponding plasma metabolome, with tissue concordant plasma changes offering surrogate metabolite markers of myocardial latent vulnerability. Thus, Kir6.2 deficit precipitates multiome reorganization, mapping a comprehensive atlas of the K_ATP channel dependent landscape.

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.

The Myocardial Microenvironment Modulates the Biology of Transplanted Mesenchymal Stem Cells

PURPOSE

The maximal efficacy of cell therapy depends on the survival of stem cells, as well as on the phenotypic and biologic changes that may occur on these cells after transplantation. It has been hypothesized that the post-ischemic myocardial microenvironment can play a critical role in these changes, potentially affecting the survival and reparative potential of mesenchymal stem cells (MSCs). Here, we use a dual reporter gene sensor for the in vivo monitoring of the phenotype of MSCs and study their therapeutic effect on cardiac function.

PROCEDURES

The mitochondrial sensor was tested in cell culture in response to different mitochondrial stressors. For in vivo testing, MSCs (3 × 10⁵) were delivered in a murine ischemia-reperfusion (IR) model. Bioluminescence imaging was used to assess the mitochondrial biology and the viability of transplanted MSCs, while high-resolution ultrasound provided a non-invasive analysis of cardiac contractility and dyssynchrony.

RESULTS

The mitochondrial sensor showed increased activity in response to mitochondrial stressors. Furthermore, when tested in the living subject, it showed a significant increase in mitochondrial dysfunction in MSCs delivered in IR, compared with those delivered under sham conditions. Importantly, MSCs delivered to ischemic hearts, despite their mitochondrial stress and poor survival, were able to induce a significant improvement in cardiac function, through decreased collagen deposition and resynchronization/contractility of left ventricular wall motion.

CONCLUSIONS

The ischemic myocardium induces changes in the phenotype of transplanted MSCs. Despite their limited survival, MSCs still elicit a certain therapeutic response, as evidenced by improvement in myocardial remodeling and cardiac function. Maximization of the survival and reparative efficacy of stem cells remains a key for the success of stem cell therapies.

Screening for regenerative therapy responders in heart failure

Risk of outcome variability challenges therapeutic innovation. Selection of the most suitable candidates is predicated on reliable response indicators. Especially for emergent regenerative biotherapies, determinants separating success from failure in achieving disease rescue remain largely unknown. Accordingly, (pre)clinical development programs have placed increased emphasis on the multi-dimensional decoding of repair capacity and disease resolution, attributes defining responsiveness. To attain regenerative goals for each individual, phenotype-based patient selection is poised for an upgrade guided by new insights into disease biology, translated into refined surveillance of response regulators and deep learning-amplified clinical decision support.

Adenylate kinase AK2 isoform integral in embryo and adult heart homeostasis

Adenylate kinase2 (AK2) catalyzes trans-compartmental nucleotide exchange, but the functional implications of this mitochondrial intermembrane isoform is only partially understood. Here, transgenic AK2-/- null homozygosity was lethal early in embryo, indicating a mandatory role for intact AK2 in utero development. In the adult, conditional organ-specific ablation of AK2 precipitated abrupt heart failure with Krebs cycle and glycolytic metabolite buildup, suggesting a vital contribution to energy demanding cardiac performance. Depressed pump function recovered to pre-deletion levels overtime, suggestive of an adaptive response. Compensatory upregulation of phosphotransferase AK1, AK3, AK4 isozymes, creatine kinase isoforms, and hexokinase, along with remodeling of cell cycle/growth genes and mitochondrial ultrastructure supported organ rescue. Taken together, the requirement of AK2 in early embryonic stages, and the immediate collapse of heart performance in the AK2-deficient postnatal state underscore a primordial function of the AK2 isoform. Unsalvageable in embryo, loss of AK2 in the adult heart was recoverable, underscoring an AK2-integrated bioenergetics system with innate plasticity to maintain homeostasis on demand.

[89Zr]Zr-DBN labeled cardiopoietic stem cells proficient for heart failure

INTRODUCTION

Radiolabeling of stem cells with a positron emitting radioisotope represents a major advancement in regenerative biotherapy enabling non-invasive imaging. To assess the value of such an approach in a clinically relevant scenario, the tolerability and therapeutic aptitude of [89Zr]zirconium-p-isothiocyanatobenzyl-desferrioxamine ([89Zr]Zr-DBN) labeled human cardiopoietic stem cells (CPs) were evaluated in a model of ischemic heart failure.

METHODS AND RESULTS

[89Zr]Zr-DBN based radiolabeling of human CPs yielded [89Zr]Zr-DBN-CPs with radioactivity yield of 0.70 ± 0.20 MBq/106 cells and excellent label stability. Compared to unlabeled cell counterparts, [89Zr]Zr-DBN-CPs maintained morphology, viability, and proliferation capacity with characteristic expression of mesodermal and pro-cardiogenic transcription factors defining the cardiopoietic phenotype. Administered in chronically infarcted murine hearts, [89Zr]Zr-DBN-CPs salvaged cardiac pump failure, documented by improved left ventricular ejection fraction not inferior to unlabeled CPs and notably superior to infarcted hearts without cell treatment.

CONCLUSION

The present study establishes that [89Zr]Zr-DBN labeling does not compromise stem cell identity or efficacy in the setting of heart failure, offering a non-invasive molecular imaging platform to monitor regenerative biotherapeutics post-transplantation.

Brachyury engineers cardiac repair competent stem cells

To optimize the regenerative proficiency of stem cells, a cardiopoietic protein-based cocktail consisting of multiple growth factors has been developed and advanced into clinical trials for treatment of ischemic heart failure. Streamlining the inductors of cardiopoiesis would address the resource intensive nature of the current stem cell enhancement protocol. To this end, the microencapsulated-modified-mRNA (M³ RNA) technique was here applied to introduce early cardiogenic genes into human adipose-derived mesenchymal stem cells (AMSCs). A single mesodermal transcription factor, Brachyury, was sufficient to trigger high expression of cardiopoietic markers, Nkx2.5 and Mef2c. Engineered cardiopoietic stem cells (eCP) featured a transcriptome profile distinct from pre-engineered AMSCs. In vitro, eCP demonstrated protective antioxidant capacity with enhanced superoxide dismutase expression and activity; a vasculogenic secretome driving angiogenic tube formation; and macrophage polarizing immunomodulatory properties. In vivo, in a murine model of myocardial infarction, intramyocardial delivery of eCP (600 000 cells per heart) improved cardiac performance and protected against decompensated heart failure. Thus, heart repair competent stem cells, armed with antioxidant, vasculogenic, and immunomodulatory traits, are here engineered through a protein-independent single gene manipulation, expanding the available regenerative toolkit.

Deleterious mtDNA mutations are common in mature oocytes

Heritable mitochondrial DNA (mtDNA) mutations are common, yet only a few recurring pathogenic mtDNA variants account for the majority of known familial cases in humans. Purifying selection in the female germline is thought to be responsible for the elimination of most harmful mtDNA mutations during oogenesis. Here we show that deleterious mtDNA mutations are abundant in ovulated mature mouse oocytes and preimplantation embryos recovered from PolG mutator females but not in their live offspring. This implies that purifying selection acts not in the maternal germline per se, but during post-implantation development. We further show that oocyte mtDNA mutations can be captured and stably maintained in embryonic stem cells and then reintroduced into chimeras, thereby allowing examination of the effects of specific mutations on fetal and postnatal development.

Cardiopoietic stem cell therapy restores infarction-altered cardiac proteome

Cardiopoietic stem cells have reached advanced clinical testing for ischemic heart failure. To profile their molecular influence on recipient hearts, systems proteomics was here applied in a chronic model of infarction randomized with and without human cardiopoietic stem cell treatment. Multidimensional label-free tandem mass spectrometry resolved and quantified 3987 proteins constituting the cardiac proteome. Infarction altered 450 proteins, reduced to 283 by stem cell treatment. Notably, cell therapy non-stochastically reversed a majority of infarction-provoked changes, remediating 85% of disease-affected protein clusters. Pathway and network analysis decoded functional reorganization, distinguished by prioritization of vasculogenesis, cardiac development, organ regeneration, and differentiation. Subproteome restoration nullified adverse ischemic effects, validated by echo-/electro-cardiographic documentation of improved cardiac chamber size, reduced QT prolongation and augmented ejection fraction post-cell therapy. Collectively, cardiopoietic stem cell intervention transitioned infarcted hearts from a cardiomyopathic trajectory towards pre-disease. Systems proteomics thus offers utility to delineate and interpret complex molecular regenerative outcomes.

Solute Carrier Transportome in Chemotherapy-Induced Adverse Drug Reactions

Members of the solute carrier (SLC) family of transporters are responsible for the cellular influx of a broad range of endogenous compounds and xenobiotics. These proteins are highly expressed in the gastrointestinal tract and eliminating organs such as the liver and kidney, and are considered to be of particular importance in governing drug absorption and elimination. Many of the same transporters are also expressed in a wide variety of organs targeted by clinically important anticancer drugs, directly affect cellular sensitivity to these agents, and indirectly influence treatment-related side effects. Furthermore, targeted intervention strategies involving the use of transport inhibitors have been recently developed, and have provided promising lead candidates for combinatorial therapies associated with decreased toxicity. Gaining a better understanding of the complex interplay between transporter-mediated on-target and off-target drug disposition will help guide the further development of these novel treatment strategies to prevent drug accumulation in toxicity-associated organs, and improve the safety of currently available treatment modalities. In this report, we provide an update on this rapidly emerging field with particular emphasis on anticancer drugs belonging to the classes of taxanes, platinum derivatives, nucleoside analogs, and anthracyclines.

Ventricular remodeling in ischemic heart failure stratifies responders to stem cell therapy

Response to stem cell therapy in heart failure is heterogeneous, warranting a better understanding of outcome predictors. This study assessed left ventricular volume, a surrogate of disease severity, on cell therapy benefit. Small to large infarctions were induced in murine hearts to model moderate, advanced, and end‐stage ischemic cardiomyopathy. At 1 month postinfarction, cardiomyopathic cohorts with comparable left ventricular enlargement and dysfunction were randomized 1:1 to those that either received sham treatment or epicardial delivery of cardiopoietic stem cells (CP). Progressive dilation and pump failure consistently developed in sham. In comparison, CP treatment produced significant benefit at 1 month post‐therapy, albeit with an efficacy impacted by cardiomyopathic stage. Advanced ischemic cardiomyopathy was the most responsive to CP‐mediated salvage, exhibiting both structural and functional restitution, with proteome deconvolution substantiating that cell therapy reversed infarction‐induced remodeling of functional pathways. Moderate cardiomyopathy was less responsive to CP therapy, improving contractility but without reversing preexistent heart enlargement. In end‐stage disease, CP therapy showed the least benefit. This proof‐of‐concept study thus demonstrates an optimal window, or “Goldilocks principle,” of left ventricular enlargement for maximized stem cell‐based cardiac repair. Disease severity grading, prior to cell therapy, should be considered to inform regenerative medicine interventions.

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.

Increasing the Efficacy of Stem Cell Therapy via Triple-Function Inorganic Nanoparticles

Stem cell therapy in heart disease is challenged by mis-injection, poor survival, and low cell retention. Here, we describe a biocompatible multifunctional silica-iron oxide nanoparticle to help solve these issues. The nanoparticles were made via an in situ growth of Fe₃O₄ nanoparticles on both the external surfaces and pore walls of mesocellular foam silica nanoparticles. In contrast to previous work, this approach builds a magnetic moiety inside the pores of a porous silica structure. These materials serve three roles: drug delivery, magnetic manipulation, and imaging. The addition of Fe₃O₄ to the silica nanoparticles increased their colloidal stability, T₂-based magnetic resonance imaging contrast, and superparamagnetism. We then used the hybrid materials as a sustained release vehicle of insulin-like growth factor-a pro-survival agent that can increase cell viability. In vivo rodent studies show that labeling stem cells with this nanoparticle increased the efficacy of stem cell therapy in a ligation/reperfusion model. The nanoparticle-labeled cells increase the mean left ventricular ejection fraction by 11 and 21% and the global longitudinal strain by 24 and 34% on days 30 and 60, respectively. In summary, this multifunctional nanomedicine improves stem cell survival via the sustained release of pro-survival agents.

M3RNA Drives Targeted Gene Delivery in Acute Myocardial Infarction

IMPACT STATEMENT

The M³RNA (microencapsulated modified messenger RNA) platform is an approach to deliver messenger RNA (mRNA) in vivo, achieving a nonintegrating and viral-free approach to gene therapy. This technology was, in this study, tested for its utility in the myocardium, providing a unique avenue for targeted gene delivery into the freshly infarcted myocardial tissue. This study provides the evidentiary basis for the use of M³RNA in the heart through depiction of its performance in cultured cells, healthy rodent myocardium, and acutely injured porcine hearts. By testing the technology in large animal models of infarction, compatibility of M³RNA with current coronary intervention procedures was verified.

Drug transporters and anthracycline-induced cardiotoxicity

The solute carrier superfamily comprises of uptake transporters that can contribute to the absorption and elimination of a broad array of clinically important drugs. Recent studies have suggested that the tissue-specific expression of these transporters may have important consequences for an individual's susceptibility to drug-induced organ damage or to drug–drug interactions. Polymorphic variants have been identified in genes encoded by this family, and some of these have been associated with functional changes in transport function and response to anthracycline-induced toxicity and efficacy. Here, we review recent advances in the role solute carrier transporters play in anthracycline-induced cardiotoxicity, highlight potential implications of genetic variants that may contribute to drug response and discuss novel technologies to study mechanisms of anthracycline transport.

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.

Towards the standardization of stem cell therapy studies for ischemic heart diseases: Bridging the gap between animal models and the clinical setting

Today there is an increasing demand for heart transplantations for patients diagnosed with heart failure. Though, shortage of donors as well as the large number of ineligible patients hurdle such treatment option. This, in addition to the considerable number of transplant rejections, has driven the clinical research towards the field of regenerative medicine. Nonetheless, to date, several stem cell therapies tested in animal models fall by the wayside and when they meet the criteria to clinical trials, subjects often exhibit modest improvements. A main issue slowing down the admission of such therapies in the domain of human trials is the lack of protocol standardization between research groups, which hampers comparison between different approaches as well as the lack of thought regarding the clinical translation. In this sense, given the large amount of reports on stem cell therapy studies in animal models reported in the last 3years, we sought to evaluate their advantages and limitations towards the clinical setting and provide some suggestions for the forthcoming investigations. We expect, with this review, to start a new paradigm on regenerative medicine, by evoking the debate on how to plan novel stem cell therapy studies with animal models in order to achieve more consistent scientific production and accelerate the admission of stem cell therapies in the clinical setting.

Mitochondrial Dynamics and Heart Failure

Mitochondrial dynamics, fission and fusion, were first identified in yeast with investigation in heart cells beginning only in the last 5 to 7 years. In the ensuing time, it has become evident that these processes are not only required for healthy mitochondria, but also, that derangement of these processes contributes to disease. The fission and fusion proteins have a number of functions beyond the mitochondrial dynamics. Many of these functions are related to their membrane activities, such as apoptosis. However, other functions involve other areas of the mitochondria, such as OPA1's role in maintaining cristae structure and preventing cytochrome c leak, and its essential (at least a 10 kDa fragment of OPA1) role in mtDNA replication. In heart disease, changes in expression of these important proteins can have detrimental effects on mitochondrial and cellular function.