Fifteen years of bone marrow mononuclear cell therapy in acute myocardial infarction

Integrin β2 Plays a Significant Role in Therapeutic Angiogenesis Through Hematopoietic Stem Cell Transplantation

The efficacy of hematopoietic stem cell (HSC) therapy for cerebral infarction has been previously demonstrated. However, the lack of response in some patients has hindered its widespread use. To establish HSC therapy as a standard treatment, it is important to examine the causes of non-responsiveness. In this study, we aimed to identify the specifications of transplanted cells based on their therapeutic mechanisms to predict treatment success. We found that HSC therapy activates injured cerebral endothelial cells via gap junctions because cell adhesion between HSCs and the endothelium plays an essential role in cellular communication via gap junctions. The expression of the adhesion molecule integrin β2 (CD18) in CD34-positive (CD34+) cells was identified as critical for the therapeutic effect on cerebral infarction in a murine model. Cells with low CD18 expression exhibited a weaker therapeutic effect than cells with high CD18 expression, even when the same number of HSCs was administered. The expression of CD18 in CD34+ cells can be used as a specification marker for transplanted HSCs and is useful for identifying non-responders. Furthermore, quantification of CD18 expression is crucial for evaluating the cellular potential of cell-based therapies for diseases where therapeutic effects are mediated through cell adhesion.

Assessing the Potential Benefits of Stem Cell Therapy in Cardiac Regeneration for Patients With Ischemic Heart Disease

Myocardial infarction, commonly known as a heart attack, or ischemic heart disease (IHD), remains one of the most fatal health conditions worldwide due to the limited regenerative capacity of the heart muscle after infarction. Conventional medical treatments primarily focus on symptom control and tissue preservation but fail to address the loss of cardiomyocytes, the cells responsible for heart contraction. This systematic review explores the hypothesis that stem cell therapies can enhance cardiac regeneration by replacing or repairing damaged myocardium, with a focus on mesenchymal stem cells (MSCs), induced pluripotent stem cells (iPSCs), and embryonic stem cells (ESCs). The review was restricted to literature published between 2015 and 2024, sourced from PubMed, Web of Science, and Google Scholar. This timeframe reflects advances in stem cell research and regenerative therapies. Findings from trials such as Bone Marrow-Derived Mononuclear Cell Therapy in Acute Myocardial Infarction (BAMI) and Cardiopoietic Stem Cell Therapy in Heart Failure (C-CURE) suggest that stem cell therapies may improve left ventricular ejection fraction (LVEF) and reduce infarct size. However, the heterogeneity of trials, small sample sizes, and short follow-up durations limit the generalizability of these results. Long-term benefits, including improved survival rates and reduced hospital readmissions, remain inconclusive. Ethical concerns, particularly the use of ESCs, pose additional challenges, including controversies over embryonic sources and varying regulatory landscapes. Key areas for advancement include optimizing stem cell survival and differentiation, with genetic engineering to enhance tissue repair capabilities considered the most critical for improving clinical outcomes. The integration of regenerative treatments such as extracellular vesicle therapy, derived from stem cells to modulate repair, also shows promise. Imaging techniques, such as MRI and PET, provide real-time monitoring of stem cell effects, offering insights into therapeutic efficacy and safety. Despite promising results from preclinical models and early-phase trials, the full therapeutic potential of stem cell therapy for IHD remains unrealized. Effective treatment protocols, addressing patient-specific factors, ethical considerations, and long-term outcome evaluations, are essential. This review emphasizes the need for ongoing research and clinical development to maximize the potential of stem cell-based approaches in cardiac repair.

Comparing the effect of bone marrow mono-nuclear cells with mesenchymal stem cells after acute myocardial infarction on improvement of left ventricular function: a meta-analysis of clinical trials

BACKGROUND

The effect of transplantation of bone-marrow mononuclear cells (BM-MNCs) and mesenchymal stem cells (MSCs) on ejection fraction (LVEF) has been studied in patients with acute myocardial infarction (AMI) in clinical trials. This raises the question that which type of cell may help improve LVEF better in AMI patients. No meta-analysis of clinical trials has yet addressed this question.

METHODS

Electronic databases were searched thoroughly to find eligible trials on the effects of transplantation of BM-MNCs and MSCs in patients with AMI. The primary outcome was improvement in LVEF. Data were synthesized using random-effects meta-analysis. For maximizing the credibility of subgroup analysis, we used the instrument for assessing the Credibility of Effect Modification of Analyses (ICEMAN) for meta-analyses.

RESULTS

A total of 36 trials (26 on BM-MNCs and 10 on MSCs) with 2489 patients (1466 were transplanted [1241 with BM-MNCs and 225 with MSCs] and 1023 as controls) were included. Both types of cells showed significant improvements in ejection fraction in short-term follow-up (BM-MNCs: WMD = 2.13%, 95% CI = 1.23 to 3.04, p < 0.001; MSCs: WMD = 3.71%, 95% CI = 2.32 to 5.09, p < 0.001), and according to ICEMAN criteria, MSCs are more effective. For selected population of patients who received stem cell transplantation in early course after AMI (less than 11 days), this effect was even more pronounced (BM-MNC: WMD = 3.07%, 95% CI = 1.97 to 4.17, p < 0.001, I2 = 40.7%; MSCs: WMD = 5.65%, 95% CI = 3.47 to 7.84, p < 0.001, I2 = 84.6%).

CONCLUSION

Our results showed that transplantation of MSCs after AMI might increase LVEF more than BM-MNCs; also, based on ICEMAN, there was likely effect modification between subgroups although uncertainty still remained.

Five‐year follow‐up of intracoronary autologous cell therapy in acute myocardial infarction: the REGENERATE‐AMI trial

Aims

The long‐term outcomes of the intracoronary delivery of autologous bone marrow‐derived cells (BMCs) after acute myocardial infarction are not well established. Following the promising 1 year results of the REGENERATE‐AMI trial (despite it not achieving its primary endpoint), this paper presents the analysis of the 5 year clinical outcomes of these acute myocardial infarction patients who were treated with an early intracoronary autologous BMC infusion or placebo.

Methods and results

A 5 year follow‐up of major adverse cardiac events (defined as the composite of all‐cause death, recurrent myocardial infarction, and all coronary revascularization) and of rehospitalization for heart failure was completed in 85 patients (BMC n = 46 and placebo n = 39). The incidence of major adverse cardiac events was similar between the BMC‐treated patients and the placebo group (26.1% vs. 18.0%, P = 0.41). There were no cases of cardiac death in either group, but an increase in non‐cardiac death was seen in the BMC group (6.5% vs. 0%, P = 0.11). The rates of recurrent myocardial infarction and repeat revascularization were similar between the two groups. There were no cases of rehospitalization for heart failure in either group.

Conclusion

This 5 year follow‐up analysis of the REGENERATE‐AMI trial did not show an improvement in clinical outcomes for patients treated with cell therapy. This contrasts with the 1 year results which showed improvements in the surrogate outcome measures of ejection fraction and myocardial salvage index.

Cell Therapy Improves Cardiac Function in Anthracycline-Induced Cardiomyopathy Preclinical Models: A Systematic Review and Meta-Analysis

Although anthracycline (ANT)-based treatment strongly contributes to cancer survivorship, the use of these agents is limited by the risk of cardiotoxicity. For those patients who evolve to heart failure, myocardial regenerative approaches are of particular interest, and a growing body of preclinical studies has been investigating the use of cell therapy for ANT-induced cardiomyopathy (AIC). However, since animal models and modalities of cell therapy are highly heterogeneous between studies, the efficacy of cell therapy for AIC is not clear. Thus, we conducted a systematic review and meta-analysis of experimental studies reporting the use of cell therapy with mesenchymal stromal cells (MSC) or bone marrow mononuclear cells (BMMNC) in animal models of AIC with regard to global cardiac function. The Medline, EMBASE, and Web of Science databases were searched from inception to November 2019. Two reviewers independently extracted data on study quality and the results of left ventricular ejection fraction (LVEF) and fractional shortening (FS) obtained by echocardiography. The quality of outcomes was assessed using the Cochrane, Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies (CAMARADES), and SYRCLE bias risk tools. Pooled random-effects modeling was used to calculate pooled mean differences (MD) and 95% confidence intervals (CIs). Twenty-two studies comprising 381 small animals (rabbits and rodents) were included. A pooled meta-analysis of all treatments showed that cell therapy increased LVEF by 9.87% (95% CI 7.25-12.50, P < 0.00001) and FS by 7.80% (95% CI 5.68-9.92, P < 0.00001) in small animals with AIC. Cell therapy with MSC/BMMNC is effective to mitigate the deleterious effects of ANT on cardiac function in preclinical models. Nevertheless, due to the small number of studies and considerable heterogeneity, future translational studies must be designed to diminish between-study discrepancies and increase similarity to the clinical landscape.

Cardiac cell therapy: Current status, challenges and perspectives

Although the initial clinical trials of cardiac cell therapy have failed to demonstrate unequivocal clinical benefits, the accumulation of preclinical data gathered in parallel can now help us to understand the main causes of failures, while providing mechanistic insights that may be leveraged to improve the outcomes of subsequent clinical studies using cells or their secreted products. This review briefly describes the current status of clinical trials, discusses the potential mechanisms of action of the grafted cells, and the impact of this knowledge on the design of future studies, and finally draws some perspectives.

Clot-Derived Contaminants in Transplanted Bone Marrow Mononuclear Cells Impair the Therapeutic Effect in Stroke

Background and Purpose—

The beneficial effects of bone marrow mononuclear cell (BM-MNC) transplantation in preclinical experimental stroke have been reliably demonstrated. However, only overall modest effects in clinical trials were observed. We have investigated and reported a cause of the discrepancy between the preclinical and clinical studies.

Methods—

To investigate the possible cause of low efficacy of BM-MNC transplantation in experimental stroke, we have focused on blood clot formation, which is not uncommon in human bone marrow aspirates. To evaluate the effects of clot-derived contaminants in transplanted BM-MNC on stroke outcome, a murine stroke model was used.

Results—

We show that BM-MNC separated by an automatic cell isolator (Sepax2), which does not have the ability to remove clots, did not attenuate brain atrophy after stroke. In contrast, manually isolated, clot-free BM-MNC exerted therapeutic effects. Clot-derived contaminants were also transplanted intravenously to poststroke mice. We found that the transplanted contaminants were trapped at the peristroke area, which were associated with microglial/macrophage activation.

Conclusions—

Clot-derived contaminants in transplanted BM-MNC nullify therapeutic effects in experimental stroke. This may explain neutral results in clinical trials, especially in those using automated stem cell separators that lack the ability to remove clot-derived contaminants.

Visual Overview—

An online visual overview is available for this article.

Umbilical cord-derived mesenchymal stromal cells in cardiovascular disease: review of preclinical and clinical data

The human umbilical cord has recently emerged as an attractive potential source of mesenchymal stromal cells (MSCs) to be adopted for use in regenerative medicine. Umbilical cord MSCs (UC-MSCs) not only share the same features of all MSCs such as multi-lineage differentiation, paracrine functions and immunomodulatory properties, they also have additional advantages, such as no need for bone marrow aspiration and higher self-renewal capacities. They can be isolated from various compartments of the umbilical cord (UC) and can be used for autologous or allogeneic purposes. In the past decade, they have been adopted in cardiovascular disease and have shown promising results mainly due to their pro-angiogenic and anti-inflammatory properties. This review offers an overview of the biological properties of UC-MSCs describing available pre-clinical and clinical data with respect to their potential therapeutic use in cardiovascular regeneration, with current challenges and future directions discussed.

Moving forward on the pathway of cell-based therapies in ischemic heart disease and heart failure - time for new recommendations?

Although substantial advances have been made in treating ischemic heart disease and subsequent heart failure, the overall morbidity and mortality from these conditions remain high. Stem cell-based therapy has emerged as a promising approach for prompting cardiac rejuvenation. Various cell types have been tested in the clinical arena, proving consistent safety results. As for efficiency outcomes, contradictory findings have been reported, partly due to inconsistency in study protocols but also due to poor survival, engraftment and differentiation of transplanted cells in the hostile milieu of the ischemic host tissue. Studies have varied in terms of route of delivery, type and dose of implanted stem cells, patient selection and randomization, and assessment of therapeutic effect. Founded on the main achievements and challenges within almost 20 years of research, a number of official documents have been published by leading experts in the field. Core recommendations have focused on developing and optimizing effective strategies to enrich cell retention and their regenerative potential. Issued consensus and position papers have stemmed from an unmet need to provide a harmonized framework for future research, resulting in improved therapeutic application of cell-based therapies for cardiac regeneration and repair.

The Winding Road of Cardiac Regeneration-Stem Cell Omics in the Spotlight

Despite significant progress in treating ischemic cardiac disease and succeeding heart failure, there is still an unmet need to develop effective therapeutic strategies given the persistent high-mortality rate. Advances in stem cell biology hold great promise for regenerative medicine, particularly for cardiac regeneration. Various cell types have been used both in preclinical and clinical studies to repair the injured heart, either directly or indirectly. Transplanted cells may act in an autocrine and/or paracrine manner to improve the myocyte survival and migration of remote and/or resident stem cells to the site of injury. Still, the molecular mechanisms regulating cardiac protection and repair are poorly understood. Stem cell fate is directed by multifaceted interactions between genetic, epigenetic, transcriptional, and post-transcriptional mechanisms. Decoding stem cells' "panomic" data would provide a comprehensive picture of the underlying mechanisms, resulting in patient-tailored therapy. This review offers a critical analysis of omics data in relation to stem cell survival and differentiation. Additionally, the emerging role of stem cell-derived exosomes as "cell-free" therapy is debated. Last but not least, we discuss the challenges to retrieve and analyze the huge amount of publicly available omics data.

Clinical efficacy of icotinib in patients with advanced nonsquamous non-small cell lung cancer with unknown EGFR mutation status that failed to respond to second-line chemotherapy

Background

Evaluation of the clinical efficacy and safety of icotinib in advanced nonsquamous non-small cell lung cancer (NSCLC) patients with an unknown EGFR mutation who failed to respond to second-line chemotherapy.

Methods

Seventy-six cases of advanced nonsquamous NSCLC were involved in this study from seven hospitals from the Hubei province of China. Patients with an unknown EGFR mutation status were treated with Icotinib, at an oral dosage of 125 mg three times daily. All patients were followed up for at least 1 year to observe the efficacy, adverse reactions, and 1-year survival.

Results

The patients' overall objective response rate (ORR) was 34.2%, the disease control rate (DCR) was 75.0%, the clinical benefit rate (CBR) was 80.2%, the median progression-free survival (PFS) was 11.0 months, the median overall survival (OS) was 16.9 months, and the 1-year OS rate was 63.2%. Gender and smoking history were associated with the DCR (P<0.05). Both PFS and OS were significantly higher in groups that had pre-accepted ≤6 cycles of chemotherapy than in groups that had pre-accepted >6 cycles.

Conclusions

Our results demonstrated that icotinib had a better DCR or clinical benefits for treating the patients with unknown EGFR mutation who failed to respond to second-line chemotherapy in advanced nonsquamous NSCLC, and the adverse effects are tolerable.

Inverse opal substrate-loaded mesenchymal stem cells contribute to decreased myocardial remodeling after transplantation into acute myocardial infarction mice

Background

The two-dimensional incubation method is now the most commonly method for mesenchymal stem cell (MSC) production. however, gene expression and secretion of growth factors are relatively low; thus, the transplanted cells cannot be effectively utilized for potential clinical applications after acute myocardial infarction (AMI).

Objectives

We aimed to investigate whether our newly made substrates of inverse opal with specific surface microstructures for MSC culturing can increase the viability of the cells and can contributes to decreased myocardial remodeling after transplanted to AMI mice.

Methods

The inverse opal structure is fabricated by the convenient bottom-up approach of the self-assembly of colloidal nanoparticles. Mouse-derived MSCs were then cultured on the substrates when expanded at different times to investigate the cell growth status including morphology. Then the inverse opal substrates loaded MSCs were transplanted to AMI mice, cardiomyocyte apoptosis and LV remodeling were further compared. To explore the possible mechanisms of curation, the secretions and viability of MSCs on substrates were determined using mice ELISA kits and JC-1 mitochondrial membrane potential assay kits respectively at normal and hypoxic conditions.

Results

6 times expanded inverse opals allowed greatly the orderly growth of MSCs as compared to four (34% ± 10.6%) and two (20%±7.2%) times expanded as well as unexpanded (13%±4.1%) (P<0.001). Nearly 90% of MSCs showed orientation angle intervals of less than 30° when at the 6X expanded (89.6%±25%) compared to the percent of cells with 30°-60° (8.7%±2.6%) or ≥60° (1.7%±1.0%) orientation angle (P<0.001). After inverse opal loaded MSCs transplanted to AMI mice, greatly decreased apoptosis of cardiomyocytes (20.45%±8.64% vs.39.63%±11.71%, P<0.001) and infarction area (5.87±2.18 mm² vs 9.31±3.11 mm², P<0.001) were identified. In the end, the viability of inverse opal loaded MSCs determined by membrane potential (P<0.001) and the secretion of growth factors including VEGF-α, SDF-1 and Ang-1 (P<0.001) were both confirmed significantly higher than that of the conventional culture in petri dish.

Conclusion

The structure of inverse opal can not only adjust the arrangement of MSCs but also contribute to its orientated growth. Inverse opal loaded MSCs transplantation extremely curbed myocardial remodeling, the underlying mechanisms might be the high viability and extremely higher secretions of growth factors of MSCs as devoted by this method.

Therapeutic Use of Stem Cells for Myocardial Infarction

Myocardial infarction is a leading cause of morbidity and mortality worldwide. Although medical and surgical treatments can significantly improve patient outcomes, no treatment currently available is able to generate new contractile tissue or reverse ischemic myocardium. Driven by the recent/novel understanding that regenerative processes do exist in the myocardium—tissue previously thought not to possess regenerative properties—the use of stem cells has emerged as a promising therapeutic approach with high expectations. The literature describes the use of cells from various sources, categorizing them as either embryonic, induced pluripotent, or adult/tissue stem cells (mesenchymal, hematopoietic, skeletal myoblasts, cardiac stem cells). Many publications show the successful use of these cells to regenerate damaged myocardium in both animal and human models; however, more studies are needed to directly compare cells of various origins in efforts to draw conclusions on the ideal source. Although numerous challenges exist in this developing area of research and clinical practice, prospects are encouraging. The following aims to provide a concise review outlining the different types of stem cells used in patients after myocardial infarction.

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.