The effects of age, disease state, and granulocyte colony-stimulating factor on progenitor cell count and function in patients undergoing cell therapy for cardiac disease

Case report: Cytokine therapy and an intracoronary autologous bone marrow-derived cell infusion with Impella support in a patient with dilated cardiomyopathy and a severely reduced ejection fraction

Introduction

This is the first reported case of a patient with dilated cardiomyopathy (DCM) and severely impaired left ventricular function to receive a combined treatment of granulocyte colony-stimulating factor therapy and an intracoronary delivery of autologous bone marrow-derived mononuclear cells with percutaneous circulatory assistance (the Impella CP device; Abiomed, Danvers, MA).

Main symptoms and outcome

Three months post-treatment, the gentleman in his early 70s demonstrated an improvement in left ventricular ejection fraction (13–17%) and a reduction in New York Heart Association class from III to class I. There was also an improvement in his 6-minute walk test (147–357 meters), N-terminal pro-brain natriuretic peptide level (14,099–7,129 ng/l) and quality of life scores. There were no safety concerns during the treatment or follow-up.

Conclusion

This case report suggests combined cell and cytokine therapy with adjunctive circulatory support could be a safe and promising treatment for patients with DCM and severely reduced ejection fraction.

Transplantation of CD34+ cells for myocardial ischemia

CD34+ cells are multipotent hematopoietic stem cells also known as endothelial progenitor cells and are useful in regenerative medicine. Naturally, these cells are mobilized from the bone marrow into peripheral circulation in response to ischemic tissue injury. CD34+ cells are known for their high proliferative and differentiation capacities that play a crucial role in the repair process of myocardial damage. They have an important paracrine activity in secreting factors to stimulate vasculogenesis, reduce endothelial cells and cardiomyocytes apoptosis, remodel extracellular matrix and activate additional progenitor cells. Once they migrate to the target site, they enhance angiogenesis, neovascularization and tissue regeneration. Several trials have demonstrated the safety and efficacy of CD34+ cell therapy in different settings, such as peripheral limb ischemia, stroke and cardiovascular disease. Herein, we review the potential utility of CD34+ cell transplantation in acute myocardial infarction, refractory angina and ischemic heart failure.

Promise of autologous CD34+ stem/progenitor cell therapy for treatment of cardiovascular disease

CD34+ cells are haematopoietic stem cells used therapeutically in patients undergoing radiation or chemotherapy due to their regenerative potential and ability to restore the haematopoietic system. In animal models, CD34+ cells have been associated with therapeutic angiogenesis in response to ischaemia. Several trials have shown the potential safety and efficacy of CD34+ cell delivery in various cardiovascular diseases. Moreover, Phase III trials have now begun to explore the potential role of CD34+ cells in treatment of both myocardial and peripheral ischaemia. CD34+ cells have been shown to be safe and well-tolerated in the acute myocardial infarction (AMI), heart failure, and angina models. Several studies have suggested potential benefit of CD34+ cell therapy in patients with coronary microvascular disease as well. In this review, we will discuss the therapeutic potential of CD34+ cells, and describe the pertinent trials that have used autologous CD34+ cells in no-options refractory angina, AMI, and heart failure. Lastly, we will review the potential utility of autologous CD34+ cells in coronary endothelial and microvascular dysfunction.

Initiation of Post-Primary Tuberculosis of the Lungs: Exploring the Secret Role of Bone Marrow Derived Stem Cells

Mycobacterium tuberculosis (Mtb), the causative organism of pulmonary tuberculosis (PTB) now infects more than half of the world population. The efficient transmission strategy of the pathogen includes first remaining dormant inside the infected host, next undergoing reactivation to cause post-primary tuberculosis of the lungs (PPTBL) and then transmit via aerosol to the community. In this review, we are exploring recent findings on the role of bone marrow (BM) stem cell niche in Mtb dormancy and reactivation that may underlie the mechanisms of PPTBL development. We suggest that pathogen's interaction with the stem cell niche may be relevant in potential inflammation induced PPTBL reactivation, which need significant research attention for the future development of novel preventive and therapeutic strategies for PPTBL, especially in a post COVID-19 pandemic world. Finally, we put forward potential animal models to study the stem cell basis of Mtb dormancy and reactivation.

Nano-Vesicle (Mis)Communication in Senescence-Related Pathologies

Extracellular vesicles are a heterogeneous group of cell-derived membranous structures comprising of exosomes, apoptotic bodies, and microvesicles. Of the extracellular vesicles, exosomes are the most widely sorted and extensively explored for their contents and function. The size of the nanovesicular structures (exosomes) range from 30 to 140 nm and are present in various biological fluids such as saliva, plasma, urine etc. These cargo-laden extracellular vesicles arise from endosome-derived multivesicular bodies and are known to carry proteins and nucleic acids. Exosomes are involved in multiple physiological and pathological processes, including cellular senescence. Exosomes mediate signaling crosstalk and play a critical role in cell-cell communications. Exosomes have evolved as potential biomarkers for aging-related diseases. Aging, a physiological process, involves a progressive decline of function of organs with a loss of homeostasis and increasing probability of illness and death. The review focuses on the classic view of exosome biogenesis, biology, and age-associated changes. Owing to their ability to transport biological information among cells, the review also discusses the interplay of senescent cell-derived exosomes with the aging process, including the susceptibility of the aging population to COVID-19 infections.

Intrinsic Vascular Repair by Endothelial Progenitor Cells in Acute Coronary Syndromes: an Update Overview

Bone marrow-derived endothelial progenitor cells (EPCs) play a key role in the maintenance of endothelial homeostasis and endothelial repair at areas of vascular damage. The quantification of EPCs in peripheral blood by flow cytometry is a strategy to assess this reparative capacity. The number of circulating EPCs is inversely correlated with the number of cardiovascular risk factors and to the occurrence of cardiovascular events. Therefore, monitoring EPCs levels may provide an accurate assessment of susceptibility to cardiovascular injury, greatly improving risk stratification of patients with high cardiovascular risk, such as those with an acute myocardial infarction. However, there are many issues in the field of EPC identification and quantification that remain unsolved. In fact, there have been conflicting protocols used to the phenotypic identification of EPCs and there is still no consensual immunophenotypical profile that corresponds exactly to EPCs. In this paper we aim to give an overview on EPCs-mediated vascular repair with special focus on acute coronary syndromes and to discuss the different phenotypic profiles that have been used to identify and quantify circulating EPCs in several clinical studies. Finally, we will synthesize evidence on the prognostic role of EPCs in patients with high cardiovascular risk.

Age-Related Impaired Efficacy of Bone Marrow Cell Therapy for Myocardial Infarction Reflects a Decrease in B Lymphocytes

Treatment of myocardial infarction (MI) with bone marrow cells (BMCs) improves post-MI cardiac function in rodents. However, clinical trials of BMC therapy have been less effective. While most rodent experiments use young healthy donors, patients undergoing autologous cell therapy are older and post-MI. We previously demonstrated that BMCs from aged and post-MI donor mice are therapeutically impaired, and that donor MI induces inflammatory changes in BMC composition including reduced levels of B lymphocytes. Here, we hypothesized that B cell alterations in bone marrow account for the reduced therapeutic potential of post-MI and aged donor BMCs. Injection of BMCs from increasingly aged donor mice resulted in progressively poorer cardiac function and larger infarct size. Flow cytometry revealed fewer B cells in aged donor bone marrow. Therapeutic efficacy of young healthy donor BMCs was reduced by depletion of B cells. Implantation of intact or lysed B cells improved cardiac function, whereas intact or lysed T cells provided only minor benefit. We conclude that B cells play an important paracrine role in effective BMC therapy for MI. Reduction of bone marrow B cells because of age or MI may partially explain why clinical autologous cell therapy has not matched the success of rodent experiments.

Cellular therapies for chronic ischemic heart failure

The development of stem cell therapies for chronic ischemic heart failure is highly sought after to attempt to improve morbidity and mortality of this prevalent disease. This article reviews clinical trials that investigate stem cell therapy for chronic ischemic heart failure. To generate this review article, PubMed was searched using keywords "stem cell therapy heart failure" with the article type "Clinical Trial" selected on 10/04/2016. The raw search yielded 156 articles; 53 articles were selected for inclusion in the review between the original literature search and manual research/cross-referencing. Additional reviews and original articles were also manually researched and cross-referenced. Cellular-based therapies utilizing peripheral blood progenitor cells, bone marrow cells, mesenchymal stem cells, cells of cardiac origin, and embryonic stem cells have yielded mixed results, but some studies have shown modest efficacy. Skeletal myoblasts raised concerns about safety due to arrhythmias. Optimizing cell type and delivery method will be of critical importance in enhancing efficacy of therapy within various subsets of chronic ischemic heart failure patients. Although much more work needs to be done to optimize treatment strategies, developing stem cell therapies for chronic ischemic heart failure could be of critical importance to lessen the impactful health burden that heart failure has on patients and society.

Natural compound bavachalcone promotes the differentiation of endothelial progenitor cells and neovascularization through the RORα-erythropoietin-AMPK axis

In cardiovascular diseases, endothelial function is impaired and the level of circulating endothelial progenitor cells (EPCs) is low. This study investigated whether the natural bioactive component bavachalcone (BavaC) induces the differentiation of EPCs and neovascularization in vivo; the underlying mechanisms were also examined. We observed that the treatment of rat bone marrow–derived cells with a very low dose of BavaC significantly promoted EPC differentiation. In our hindlimb ischemia models, low–dose BavaC administered orally for 14 days stimulated the recovery of ischemic hindlimb blood flow, increased circulating EPCs, and promoted capillary angiogenesis. The BavaC treatment of rat bone marrow cells for 24 h initiated the AMP–activated protein kinase (AMPK) activity required for the differentiation of EPCs. Further testing revealed that BavaC and CGP52608, a retinoic acid receptor–related orphan receptor α (RORα) activator, enhanced the activity of RORα1 and EPO luciferase reporter gene. BavaC treatment also elevated EPO mRNA and protein expression in vitro and in vivo and the circulating EPO levels in rats. By contrast, the RORα antagonist VPR66 inhibited BavaC–induced EPO reporter activity, and differentiation of bone marrow cells into endothelial progenitor cells. Overall, this study revealed that BavaC promotes EPC differentiation and neovascularization through a RORα–EPO–AMPK axis. BavaC can be used as a promising angiogenesis agent for enhancing angiogenesis and tissue repair.

Influence of patient related factors on number of mesenchymal stromal cells reached after in vitro culture expansion for clinical treatment

BACKGROUND

Number of stromal cells injected in patients with ischaemic heart disease (IHD) may be of importance for the treatment efficacy, which in turn may be influenced by various patient-related factors. In this study, we investigate whether patient-related factors influence the number of autologous stromal cells reached after in vitro culture expansion for clinical therapy.

METHODS

Culture expansion data from 111 patients with IHD treated with autologous stromal cells in three clinical trials were used. We correlated the final cell count after two passages of cultivation with different patient factors.

RESULTS

There was a significant relation between body mass index (BMI) and the number of adipose derived stromal cells (ASCs) reached after culture expansion and for all patients included into the three studies (r = 0.375, p = .019 and r = 0.200, p = .036, respectively). Moreover, there was a significantly higher number of ASCs reached in patients with hypertension compared to those without hypertension and for all patients overall (68.8 ± 39.6 × 10⁶ vs. 39.1 ± 23.6 × 10⁶, p = .020 and 62.0 ± 55.0 × 10⁶ vs. 29.0 ± 19.3 × 10⁶, p < .001, respectively). The same tendency was seen with bone marrow derived mesenchymal stromal cells (MSCs) in patients with hypertension compared to those without hypertension (58.4 ± 61.8 × 10⁶ vs. 22.6 ± 13.3 × 10⁶, p < .001) and in males compared to females (56.4 ± 61.5 × 10⁶ vs. 30.9 ± 27.9 × 10⁶, p = .041). Moreover, a significant negative correlation between left ventricular ejection fraction and number of MSCs was found (r = -0.287, p = .017).

CONCLUSIONS

Patient related factors such as BMI, hypertension and gender may influence the number of MSCs reached after in vitro culture expansion.

An exploratory randomized control study of combination cytokine and adult autologous bone marrow progenitor cell administration in patients with ischaemic cardiomyopathy: the REGENERATE-IHD clinical trial

Aims

The effect of combined cytokine and cell therapy in ischaemic cardiomyopathy is unknown. Meta‐analyses suggest improved cardiac function with cell therapy. The optimal cell delivery route remains unclear. We investigated whether granulocyte colony‐stimulating factor (G‐CSF) alone or in combination with intracoronary (i.c.) or intramyocardial (i.m.) injection of autologous bone marrow‐derived cells (BMCs) improves cardiac function.

Methods and results

Ninety patients with symptomatic ischaemic cardiomyopathy and no further treatment options were enrolled in the randomized, placebo‐controlled, single‐centre REGENERATE‐IHD study. Randomization was to one of three arms: peripheral, i.c., or i.m. In each arm, patients were randomized to active treatment or placebo. All patients, apart from the peripheral placebo group (saline only) received G‐CSF for 5 days. The i.c. and i.m. arms received either BMCs or serum (placebo). The primary endpoint was change in LVEF at 1 year assessed by cardiac magnetic resonance imaging/computed tomography. The i.m. BMC group showed a significant improvement in LVEF of 4.99% (95% confidence interval 0.33–9.6%; P = 0.038) at 1 year. This group also showed a reduction in NYHA class at 1 year and NT‐proBNP at 6 months. No other group showed a significant change in LVEF. This finding is supported by post‐hoc between‐group comparisons.

Conclusion

We have shown that G‐CSF combined with autologous i.m. BMCs has a beneficial effect on cardiac function and symptoms. However, this result should be considered preliminary in support of a clinical benefit of i.m. stem cell infusion in ‘no option’ patients and needs further exploration in a larger study.

Collection and immunoselection of CD34+ cells: the impact of age, sex, and diabetes in patients with chronic heart failure

BACKGROUND

Mobilized peripheral blood is the most common source of CD34+ cells intended for transplantations. The collection and enrichment of CD34+ cells could be affected by various factors and there are some controversies regarding the effects of patient-related factors. The aim of this study was to assess the impact of age, sex, and diabetes on the CD34+ cell grafts in patients with chronic heart failure.

STUDY DESIGN AND METHODS

Cell grafts from 100 adult patients scheduled for autologous CD34+ cell transplantation were investigated. The CD34+ cells were collected using leukapheresis after granulocyte-colony-stimulating factor mobilization and further enriched using the immunomagnetic CD34+ selection. The number of CD34+ cells and their viability were determined by flow cytometry.

RESULTS

Older patients had significantly lower CD34+ cell counts than younger patients. The differences between men and women were not found. There was a trend toward an inverse relationship between diabetes and the CD34+ cell count, however, without any significance. No differences in the CD34+ cell viability (97.6% before and 97.9% after selection) were found. The mean CD34+ cell recovery was 59.7% and was not statistically different between age groups, sex, and diabetic patients.

CONCLUSION

Before the CD34+ cells are collected the patient's age should be considered. The study did not demonstrate a significant impact of sex and diabetes on the CD34+ cell count. While age and sex did not affect the immunoselection process, diabetes slightly reduced cell recovery. Cell viabilities before and after the cell enrichment were comparable between the tested samples.

Role of NOX2 in mediating doxorubicin-induced senescence in human endothelial progenitor cells

Senescence exerts a great impact on both biological and functional properties of circulating endothelial progenitor cells (EPCs), especially in cardiovascular diseases where the physiological process of aging is accelerated upon clinical administration of certain drugs such as doxorubicin. EPC impairment contributes to doxorubicin-induced cardiotoxicity. Doxorubicin accelerates EPC aging, although mechanisms underlying this phenomenon remain to be fully clarified. Here we investigated if Nox2 activity is able to modulate the premature senescence induced in vitro by doxorubicin in human EPCs. Results showed that in conditioned media obtained from late EPC cultures, the levels of interleukin-6, isoprostanes and nitric oxide bioavailability were increased and reduced respectively after 3h of doxorubicin treatment. These derangements returned to physiological levels when cells were co-treated with apocynin or gp91ds-tat (antioxidant and specific Nox2 inhibitors, respectively). Accordingly, Nox2 activity resulted to be activated by doxorubicin. Importantly, we found that Nox2 inhibition reduced doxorubicin-induced EPC senescence, as indicated by a lower percentage of β-gal positive EPCs. In conclusion, Nox2 activity efficiently contributes to the mechanism of oxidative stress-induced increase in premature aging conferred by doxorubicin. The importance of modulation of Nox2 in human EPCs could reveal a useful tool to restore EPC physiological function and properties.

BM ageing: Implication for cell therapy with EPCs

The bone marrow (BM) is a well-recognized source of stem/progenitor cells for cell therapy in cardiovascular diseases (CVDs). Preclinical and clinical studies suggest that endothelial progenitor cells (EPCs) contribute to reparative process of vascular endothelium and participate in angiogenesis. As for all organs and cells across the lifespan, BM and EPCs are negatively impacted by ageing due to microenvironment modifications and EPC progressive dysfunctions. The encouraging results in terms of neovascularization observed in young animals after EPC administration were mitigated in aged patients treated for ischemic CVDs. The limited efficacy of EPC-based therapy in clinical setting might be ascribed at least partly to ageing. In this review, we comprehensively discussed the age-related changes of BM and EPCs and their implication for cardiovascular cell-therapies. Finally, we examined alternative approaches under investigation to enhance EPC potency.

Efficacy of CD34+ Stem Cell Therapy in Nonischemic Dilated Cardiomyopathy Is Absent in Patients With Diabetes but Preserved in Patients With Insulin Resistance

We evaluated the association of diabetes and insulin resistance with the response to cell therapy in patients with nonischemic dilated cardiomyopathy (DCM). A total of 45 outpatients with DCM received granulocyte colony-stimulating factor for 5 days. CD34(+) cells were then collected by apheresis and injected transendocardially. Twelve patients had diabetes mellitus (DM group), 17 had insulin resistance (IR group), and 16 displayed normal glucose metabolism (no-IR group). After stimulation, we found higher numbers of CD34(+) cells in the IR group (94 ± 73 × 10(6) cells per liter) than in the no-IR group (54 ± 35 × 10(6) cells per liter) or DM group (31 ± 20 × 10(6) cells per liter; p = .005). Similarly, apheresis yielded the highest numbers of CD34(+) cells in the IR group (IR group, 216 ± 110 × 10(6) cells; no-IR group, 127 ± 82 × 10(6) cells; DM group, 77 ± 83 × 10(6) cells; p = .002). Six months after cell therapy, we found an increase in left ventricular ejection fraction in the IR group (+5.6% ± 6.9%) and the no-IR group (+4.4% ± 7.2%) but not in the DM group (-0.9% ± 5.4%; p = .035). The N-terminal pro-brain natriuretic peptide levels decreased in the IR and no-IR groups, but not in the DM group (-606 ± 850 pg/ml; -698 ± 1,105 pg/ml; and +238 ± 963 pg/ml, respectively; p = .034). Transendocardial CD34(+) cell therapy appears to be ineffective in DCM patients with diabetes. IR was associated with improved CD34(+) stem cell mobilization and a preserved clinical response to cell therapy.

SIGNIFICANCE

The present study is the first clinical study directly evaluating the effects of altered glucose metabolism on the efficacy of CD34(+) stem cell therapy in patients with nonischemic dilated cardiomyopathy. The results offer critical insights into the physiology of stem cell mobilization in heart failure and possibly an explanation for the often conflicting results obtained with stem cell therapy for heart failure. These results demonstrate that patients with dilated cardiomyopathy and diabetes do not benefit from autologous CD34(+) cell therapy. This finding could serve as a useful tool when selecting heart failure patients for future clinical studies in the field of stem cell therapy.

The hematopoietic system in the context of regenerative medicine

Hematopoietic stem cells (HSC) represent the prototype stem cell within the body. Since their discovery, HSC have been the focus of intensive research, and have proven invaluable clinically to restore hematopoiesis following inadvertent radiation exposure and following radio/chemotherapy to eliminate hematologic tumors. While they were originally discovered in the bone marrow, HSC can also be isolated from umbilical cord blood and can be "mobilized" peripheral blood, making them readily available in relatively large quantities. While their ability to repopulate the entire hematopoietic system would already guarantee HSC a valuable place in regenerative medicine, the finding that hematopoietic chimerism can induce immunological tolerance to solid organs and correct autoimmune diseases has dramatically broadened their clinical utility. The demonstration that these cells, through a variety of mechanisms, can also promote repair/regeneration of non-hematopoietic tissues as diverse as liver, heart, and brain has further increased their clinical value. The goal of this review is to provide the reader with a brief glimpse into the remarkable potential HSC possess, and to highlight their tremendous value as therapeutics in regenerative medicine.

High number of transplanted stem cells improves myocardial recovery after AMI in a porcine model

OBJECTIVE

The clinical data considering the bone marrow mononuclear cell (BMMNC) therapy in treatment for acute myocardial infarction (AMI) are controversial and the mechanisms remain unknown. Our objective was to study the cardiac function and changes in cytokine levels after administration of BMMNC in experimental AMI model.

DESIGN

Unlabeled or Super-Paramagnetic-Iron-Oxide-labeled BMMNCs or saline was injected into myocardium of 31 pigs after circumflex artery occlusion. Ejection fraction (EF) was measured preoperatively, postoperatively and at 21 days by echocardiography. Cardiac MRI was performed postoperatively and after 21 days in 7 BMMNC animals. Serum cytokine levels were measured at baseline, 24 h and 21 days. Cellular homing was evaluated comparing MRI and histology.

RESULTS

From baseline to 21 days EF decreased less in BMMNC group (EF mean control -19 SD 12 vs. BMMNC -4 SD 15 percentage points p = 0.02). Cytokine concentrations showed high variability between the animals. MRI correlated with histology in cell detection and revealed BMMNCs in the infarction area. By MRI, EF improved 11 percentage points. The improvement in EF was associated with the number of transplanted BMMNCs detected in the myocardium.

CONCLUSION

BMMNC injection after AMI improved cardiac function. Quantity of transplanted BMMNCs correlated with the improvement in cardiac function after AMI.

Stem cell therapy to treat heart ischaemia: implications for diabetes cardiovascular complications

Diabetes mellitus is a well-known risk factor for coronary artery disease (CAD), which can lead to acute myocardial infarction, chronic myocardial ischaemia and heart failure. Despite the advantages in medical treatment, percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG), morbidity and mortality is still high in patients with CAD. Along with PCI and CABG or in patients without options for revascularization, stem cell regenerative therapy in controlled trials is a possibility. Stem cells are believed to exert their actions by angiogenesis and regeneration of cardiomyocytes. Recently published clinical trials and meta-analysis of stem cell studies have shown encouraging results with increased left ventricle ejection fraction and reduced symptoms in patients with CAD and heart failure. There is some evidence of mesenchymal stem cell being more effective compared to other cell types and cell therapy may be more effective in patients with known diabetes mellitus. However, further investigations are warranted.