Exosomes secreted by cardiosphere-derived cells reduce scarring, attenuate adverse remodelling, and improve function in acute and chronic porcine myocardial infarction

Extracellular vesicles from human cardiac stromal cells up-regulate cardiomyocyte protective responses to hypoxia

BACKGROUND

Cell therapy can protect cardiomyocytes from hypoxia, primarily via paracrine secretions, including extracellular vesicles (EVs). Since EVs fulfil specific biological functions based on their cellular origin, we hypothesised that EVs from human cardiac stromal cells (CMSCLCs) obtained from coronary artery bypass surgery may have cardioprotective properties.

OBJECTIVES

This study characterises CMSCLC EVs (C_EVs), miRNA cargo, cardioprotective efficacy and transcriptomic modulation of hypoxic human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). C_EVs are compared to bone marrow mesenchymal stromal cell EVs (B_EVs) which are a known therapeutic EV type.

METHODS

Cells were characterised for surface markers, gene expression and differentiation potential. EVs were compared for yield, phenotype, and ability to protect hiPSC-CMs from hypoxia/reoxygenation injury. EV dose was normalised by both protein concentration and particle count, allowing direct comparison. C_EV and B_EV miRNA cargo was profiled and RNA-seq was performed on EV-treated hypoxic hiPSC-CMs, then data were integrated by multi-omics. Confirmatory experiments were carried out using miRNA mimics.

RESULTS

At the same dose, C_EVs were more effective than B_EVs at protecting CM integrity, reducing apoptotic markers, and cell death during hypoxia. While C_EVs and B_EVs shared 70-77% similarity in miRNA content, C_EVs contained unique miRNAs, including miR-202-5p, miR-451a and miR-142-3p. Delivering miRNA mimics confirmed that miR-1260a and miR-202/451a/142 were cardioprotective, and the latter upregulated protective pathways similar to whole C_EVs.

CONCLUSIONS

This study demonstrates the potential of cardiac tissues, routinely discarded following surgery, as a valuable source of EVs for myocardial infarction therapy. We also identify miR-1260a as protective of CM hypoxia.

Surface engineering enhances the therapeutic potential of systemically delivered extracellular vesicles following acute myocardial infarction

The objective of the study was to assess the therapeutic efficacy of targeting remote zone cardiomyocytes with cardiosphere-derived cell (CDC) extracellular vesicles (EVs) delivered via intramyocardial and intravenous routes following acute myocardial infarction (MI). Cardiomyocyte (CM) cell death plays a significant role in left ventricular (LV) remodeling and cardiac dysfunction following MI. While EVs secreted by CDCs have shown efficacy in promoting cardiac repair in preclinical models of MI, their translational potential is limited by their biodistribution and requirement for intramyocardial delivery. We hypothesized that engineering the surface of EVs to target cardiomyocytes would enhance their therapeutic efficacy following systemic delivery in a model of acute MI. CDC-derived EVs were engineered to express a CM-specific binding peptide (CMP) on their surface and characterized for size, morphology, and protein expression. Mice with acute MI underwent both intramyocardial and intravenous delivery of EVs, CMP-EVs and placebo in a double-blind study. LVEF was assessed by echo at 2- and 28-days post-MI and tissue samples processed for assessment of EV biodistribution and histological endpoints. CMP-EVs demonstrated superior cardiac targeting and retention when compared with unmodified EVs 24 h post-MI. Mice treated with IV delivered CMP-EVs demonstrated a significant improvement in LVEF and a significant reduction in remote zone cardiomyocyte apoptosis when compared with IV delivered non-targeted EVs at 28-day post-MI. Systemic administration of CMP-EVs improved cardiac function and reduced remote zone cardiomyocyte apoptosis compared with IV-administered unmodified EVs, demonstrating a strategy to optimize therapeutic EV delivery post-MI.

Research progress of exosomes from different sources in myocardial ischemia

Ischemic heart disease refers to the imbalance between the supply and demand of myocardial blood; it has various causes and results in a class of clinical diseases characterized by myocardial ischemia (MI). In recent years, the incidence of cardiovascular disease has become higher and higher, and the number of patients with ischemic heart disease has also increased year by year. Traditional treatment methods include drug therapy and surgical treatment, both of which have limitations. The former maybe develop risks of drug resistance and has more significant side effects, while the latter may damage blood vessels and risk infection. At this stage, a new cell-free treatment method needs to be explored. Many research results have shown that exosomes from different cell sources can protect the ischemic myocardium via intercellular action methods, such as promoting angiogenesis, inhibiting myocardial fibrosis, apoptosis and pyroptosis, and providing a new basis for the treatment of MI. In this review, we briefly introduce the formation and consequences of myocardial ischemia and the biology of exosomes, and then focus on the role and mechanism of exosomes from different sources in MI. We also discuss the role and mechanism of exosomes pretreated with Chinese and Western medicines on myocardial ischemia. We also discuss the potential of exosomes as diagnostic markers and therapeutic drug for MI.

Extracellular vesicle transfer of lncRNA H19 splice variants to cardiac cells

The delivery of therapeutic long non-coding RNAs (lncRNA) to the heart by extracellular vesicles (EVs) is promising for heart repair. H19, a lncRNA acting as a major regulator of gene expression within the cardiovascular system, is alternatively spliced, but the loading of its different splice variants into EVs and their subsequent uptake by recipient cardiac cells remain elusive. Here, we dissected the cellular expression of H19 splice variants and their loading into EVs secreted by Wharton-Jelly mesenchymal stromal/stem cells (WJ-MSCs). We demonstrated that overexpression of the mouse H19 gene in WJ-MSCs induces the expression of H19 splice variants at different levels. Interestingly, EVs isolated from the H19-transfected WJ-MSCs (EV-H19) showed similar expression levels for all tested splice variant sets. In vitro, we further demonstrated that EV-H19 was taken up by cardiomyocytes, fibroblasts, and endothelial cells (ECs). Finally, analysis of EV tropism in living rat myocardial slices indicated that EVs were internalized mostly by cardiomyocytes and ECs. Collectively, our results indicated that EVs can be loaded with different lncRNA splice variants and successfully internalized by cardiac cells.

Bioderived Nanoparticles for Cardiac Repair

Biobased therapy represents a promising strategy for myocardial repair. However, the limitations of using live cells, including the risk of immunogenicity of allogeneic cells and inconsistent therapeutic efficacy of autologous cells together with low stability, result in an unsatisfactory clinical outcomes. Therefore, cell-free strategies for cardiac tissue repair have been proposed as alternative strategies. Cell-free strategies, primarily based on the paracrine effects of cellular therapy, have demonstrated their potential to inhibit apoptosis, reduce inflammation, and promote on-site cell migration and proliferation, as well as angiogenesis, after an infarction and have been explored preclinically and clinically. Among various cell-free modalities, bioderived nanoparticles, including adeno-associated virus (AAV), extracellular vesicles, cell membrane-coated nanoparticles, and exosome-mimetic nanovesicles, have emerged as promising strategies due to their improved biological function and therapeutic effect. The main focus of this review is the development of existing cellular nanoparticles and their fundamental working mechanisms, as well as the challenges and opportunities. The key processes and requirements for cardiac tissue repair are summarized first. Various cellular nanoparticle modalities are further highlighted, together with their advantages and limitations. Finally, we discuss various delivery approaches that offer potential pathways for researchers and clinicians to translate cell-free strategies for cardiac tissue repair into clinical practice.

Application of Pro-angiogenic Biomaterials in Myocardial Infarction

Biomaterials have potential applications in the treatment of myocardial infarction (MI). These biomaterials have the ability to mechanically support the ventricular wall and to modulate the inflammatory, metabolic, and local electrophysiological microenvironment. In addition, they can play an equally important role in promoting angiogenesis, which is the primary prerequisite for the treatment of MI. A variety of biomaterials are known to exert pro-angiogenic effects, but the pro-angiogenic mechanisms and functions of different biomaterials are complex and diverse, and have not yet been systematically described. This review will focus on the pro-angiogenesis of biomaterials and systematically describe the mechanisms and functions of different biomaterials in promoting angiogenesis in MI.

Inhalable Stem Cell Exosomes Promote Heart Repair After Myocardial Infarction

BACKGROUND

Exosome therapy shows potential for cardiac repair after injury. However, intrinsic challenges such as short half-life and lack of clear targets hinder the clinical feasibility. Here, we report a noninvasive and repeatable method for exosome delivery through inhalation after myocardial infarction (MI), which we called stem cell-derived exosome nebulization therapy (SCENT).

METHODS

Stem cell-derived exosomes were characterized for size distribution and surface markers. C57BL/6 mice with MI model received exosome inhalation treatment through a nebulizer for 7 consecutive days. Echocardiographies were performed to monitor cardiac function after SCENT, and histological analysis helped with the investigation of myocardial repair. Single-cell RNA sequencing of the whole heart was performed to explore the mechanism of action by SCENT. Last, the feasibility, efficacy, and general safety of SCENT were demonstrated in a swine model of MI, facilitated by 3-dimensional cardiac magnetic resonance imaging.

RESULTS

Recruitment of exosomes to the ischemic heart after SCENT was detected by ex vivo IVIS imaging and fluorescence microscopy. In a mouse model of MI, SCENT ameliorated cardiac repair by improving left ventricular function, reducing fibrotic tissue, and promoting cardiomyocyte proliferation. Mechanistic studies using single-cell RNA sequencing of mouse heart after SCENT revealed a downregulation of Cd36 in endothelial cells (ECs). In an EC-Cd36fl/- conditional knockout mouse model, the inhibition of CD36, a fatty acid transporter in ECs, led to a compensatory increase in glucose utilization in the heart and higher ATP generation, which enhanced cardiac contractility. In pigs, cardiac magnetic resonance imaging showed an enhanced ejection fraction (Δ=11.66±5.12%) and fractional shortening (Δ=5.72±2.29%) at day 28 after MI by SCENT treatment compared with controls, along with reduced infarct size and thickened ventricular wall.

CONCLUSIONS

In both rodent and swine models, our data proved the feasibility, efficacy, and general safety of SCENT treatment against acute MI injury, laying the groundwork for clinical investigation. Moreover, the EC-Cd36fl/- mouse model provides the first in vivo evidence showing that conditional EC-CD36 knockout can ameliorate cardiac injury. Our study introduces a noninvasive treatment option for heart disease and identifies new potential therapeutic targets.

Macrophage-mediated heart repair and remodeling: A promising therapeutic target for post-myocardial infarction heart failure

Heart failure (HF) remains prevalent in patients who survived myocardial infarction (MI). Despite the accessibility of the primary percutaneous coronary intervention and medications that alleviate ventricular remodeling with functional improvement, there is an urgent need for clinicians and basic scientists to further reveal the mechanisms behind post-MI HF as well as investigate earlier and more efficient treatment after MI. Growing numbers of studies have highlighted the crucial role of macrophages in cardiac repair and remodeling following MI, and timely intervention targeting the immune response via macrophages may represent a promising therapeutic avenue. Recently, technology such as single-cell sequencing has provided us with an updated and in-depth understanding of the role of macrophages in MI. Meanwhile, the development of biomaterials has made it possible for macrophage-targeted therapy. Thus, an overall and thorough understanding of the role of macrophages in post-MI HF and the current development status of macrophage-based therapy will assist in the further study and development of macrophage-targeted treatment for post-infarction cardiac remodeling. This review synthesizes the spatiotemporal dynamics, function, mechanism and signaling of macrophages in the process of HF after MI, as well as discusses the emerging bio-materials and possible therapeutic agents targeting macrophages for post-MI HF.

Engineered exosomes: a potential therapeutic strategy for septic cardiomyopathy

Septic cardiomyopathy, a life-threatening complication of sepsis, can cause acute heart failure and carry a high mortality risk. Current treatments have limitations. Fortunately, engineered exosomes, created through bioengineering technology, may represent a potential new treatment method. These exosomes can both diagnose and treat septic cardiomyopathy, playing a crucial role in its development and progression. This article examines the strategies for using engineered exosomes to protect cardiac function and treat septic cardiomyopathy. It covers three innovative aspects: exosome surface modification technology, the use of exosomes as a multifunctional drug delivery platform, and plant exosome-like nanoparticle carriers. The article highlights the ability of exosomes to deliver small molecules, proteins, and drugs, summarizing several RNA molecules, proteins, and drugs beneficial for treating septic cardiomyopathy. Although engineered exosomes are a promising biotherapeutic carrier, they face challenges in clinical application, such as understanding the interaction mechanism with host cells, distribution within the body, metabolism, and long-term safety. Further research is essential, but engineered exosomes hold promise as an effective treatment for septic cardiomyopathy.

The Discovery of Extracellular Vesicles and Their Emergence as a Next-Generation Therapy

From their humble discovery as cellular debris to cementing their natural capacity to transfer functional molecules between cells, the long-winded journey of extracellular vesicles (EVs) now stands at the precipice as a next-generation cell-free therapeutic tool to revolutionize modern-day medicine. This perspective provides a snapshot of the discovery of EVs to their emergence as a vibrant field of biology and the renaissance they usher in the field of biomedical sciences as therapeutic agents for cardiovascular pathologies. Rapid development of bioengineered EVs is providing innovative opportunities to overcome biological challenges of natural EVs such as potency, cargo loading and enhanced secretion, targeting and circulation half-life, localized and sustained delivery strategies, approaches to enhance systemic circulation, uptake and lysosomal escape, and logistical hurdles encompassing scalability, cost, and time. A multidisciplinary collaboration beyond the field of biology now extends to chemistry, physics, biomaterials, and nanotechnology, allowing rapid development of designer therapeutic EVs that are now entering late-stage human clinical trials.

Y4 RNA fragments from cardiosphere-derived cells ameliorate diabetic myocardial ischemia‒reperfusion injury by inhibiting protein kinase C β-mediated macrophage polarization

The specific pathophysiological pathways through which diabetes exacerbates myocardial ischemia/reperfusion (I/R) injury remain unclear; however, dysregulation of immune and inflammatory cells, potentially driven by abnormalities in their number and function due to diabetes, may play a significant role. In the present investigation, we simulated myocardial I/R injury by inducing ischemia through ligation of the left anterior descending coronary artery in mice for 40 min, followed by reperfusion for 24 h. Previous studies have indicated that protein kinase Cβ (PKCβ) is upregulated under hyperglycemic conditions and is implicated in the development of various diabetic complications. The Y4 RNA fragment is identified as the predominant small RNA component present in the extracellular vesicles of cardio sphere-derived cells (CDCs), exhibiting notable anti-inflammatory properties in the contexts of myocardial infarction and cardiac hypertrophy. Our investigation revealed that the administration of Y4 RNA into the ventricular cavity of db/db mice following myocardial I/R injury markedly enhanced cardiac function. Furthermore, Y4 RNA was observed to facilitate M2 macrophage polarization and interleukin-10 secretion through the suppression of PKCβ activation. The mechanism by which Y4 RNA affects PKCβ by regulating macrophage activation within the inflammatory environment involves the inhibition of ERK1/2 phosphorylation In our study, the role of PKCβ in regulating macrophage polarization during myocardial I/R injury was investigated through the use of PKCβ knockout mice. Our findings indicate that PKCβ plays a crucial role in modulating the inflammatory response associated with macrophage activation in db/db mice experiencing myocardial I/R, with a notable exacerbation of this response observed upon significant upregulation of PKCβ expression. In vitro studies further elucidated the protective mechanism by which Y4 RNA modulates the PKCβ/ERK1/2 signaling pathway to induce M2 macrophage activation. Overall, our findings suggest that Y4 RNA plays an anti-inflammatory role in diabetic I/R injury, suggesting a novel therapeutic approach for managing myocardial I/R injury in diabetic individuals.

Role of Exosomes in Cardiovascular Diseases

Exosomes (EXOs) are a subgroup of extracellular vesicles (EVs) that contain numerous biologically active molecules. They exhibit an essential mode of cell communication, primarily between distinct cell populations, for the maintenance of tissue homeostasis and coordination of adaptive responses to various stresses. These intercellular communications are vital for the complex, multicellular cardiovascular system. In the last ten years, their potential role as effective tissue-to-tissue communicators has received increasing attention in cardiovascular physiology and pathology. There is growing evidence that repair of the heart and regeneration can be promoted by EXOs derived from cardiomyocytes or stem/progenitor cells. However, the underlying mechanisms remain unclear. EVs derived from different stem/progenitor cell populations have been used as cell-free therapies in different preclinical models involving cardiovascular diseases and have shown promising results. In this review, we have summarized the recent developments in EXOs research, the impact of EXOs derived from different cells on the cardiovascular system, their potential therapeutic roles as well as new diagnostic biomarkers, and the possible clinical translational outcomes.

Stem cells-derived exosomes as cardiac regenerative agents

Heart failure is a root cause of morbidity and mortality worldwide. Due to the limited regenerative capacity of the heart following myocardial injury, stem cell-based therapies have been considered a hopeful approach for improving cardiac regeneration. In recent years, different kinds of cell products have been investigated regarding their potential to treat patients with heart failure. Despite special attention to cell therapy and its products, therapeutic efficacy has been disappointing, and clinical application is not affordable. In the past few years, a subset of small extracellular vehicles (EVs), commonly known as "exosomes," was reported to grant regenerative and cardioprotective signals at a value similar to their donor cells. The conceptual advantage is that they may be ideally used without evoking a relevant recipient immune response or other adverse effects associated with viable cells. The evidence related to their beneficial effects in animal models of heart failure is rapidly growing. However, there is remarkable heterogeneity regarding source cells, isolation process, effective dosage, and delivery mode. This brief review will focus on the latest research and debates on regenerative potential and cardiac repair of exosomes from different sources, such as cardiac/non-cardiac stem, somatic cells, and progenitor cells. Overall, the current state of research on exosomes as an experimental therapy for heart diseases will be discussed.

The pig as an optimal animal model for cardiovascular research

Cardiovascular disease is a worldwide health problem and a leading cause of morbidity and mortality. Preclinical cardiovascular research using animals is needed to explore potential targets and therapeutic options. Compared with rodents, pigs have many advantages, with their anatomy, physiology, metabolism and immune system being more similar to humans. Here we present an overview of the available pig models for cardiovascular diseases, discuss their advantages over other models and propose the concept of standardized models to improve translation to the clinical setting and control research costs.

Progress in extracellular vesicle homeostasis as it relates to cardiovascular diseases

Extracellular vesicles (EVs) are involved in both physiological and pathological processes in many organ systems and are essential in mediating intercellular communication and maintaining organismal homeostasis. It is helpful to propose new strategies for disease treatment by elucidating the mechanisms of EV release and sorting. An increasing number of studies have shown that there is specific homeostasis in EVs, which is helpful for the human body to carry out physiological activities. In contrast, an EV homeostasis im-balance promotes or accelerates disease onset and development. Alternatively, regulating the quality of EVs can maintain homeostasis and even achieve the purpose of treating conditions. An analysis of the role of EV homeostasis in the onset and development of cardiovascular disease is presented in this review. This article also summarizes the methods that regulate EV homeostasis and their application in cardiovascular diseases. In particular, this study focuses on the connection between EV steady states and the cardiovascular system and the potential value of EVs in treating cardiovascular diseases.

Delivery-mediated exosomal therapeutics in ischemia-reperfusion injury: advances, mechanisms, and future directions

Ischemia-reperfusion injury (IRI) poses significant challenges across various organ systems, including the heart, brain, and kidneys. Exosomes have shown great potentials and applications in mitigating IRI-induced cell and tissue damage through modulating inflammatory responses, enhancing angiogenesis, and promoting tissue repair. Despite these advances, a more systematic understanding of exosomes from different sources and their biotransport is critical for optimizing therapeutic efficacy and accelerating the clinical adoption of exosomes for IRI therapies. Therefore, this review article overviews the administration routes of exosomes from different sources, such as mesenchymal stem cells and other somatic cells, in the context of IRI treatment. Furthermore, this article covers how the delivered exosomes modulate molecular pathways of recipient cells, aiding in the prevention of cell death and the promotions of regeneration in IRI models. In the end, this article discusses the ongoing research efforts and propose future research directions of exosome-based therapies.

Engineered Exosomes with Growth Differentiation Factor-15 Overexpression Enhance Cardiac Repair After Myocardial Injury

Background

Cardiac repair remains a thorny issue for survivors of acute myocardial infarction (AMI), due to the regenerative inertia of myocardial cells. Cell-free therapies, such as exosome transplantation, have become a potential strategy for myocardial injury. The aim of this study was to investigate the role of engineered exosomes in overexpressing Growth Differentiation Factor-15 (GDF-15) (GDF15-EVs) after myocardial injury, and their molecular mechanisms in cardiac repair.

Methods

H9C2 cells were transfected with GDF-15 lentivirus or negative control. The exosomes secreted from H9C2 cells were collected and identified. The cellular apoptosis and autophagy of H2O2-injured H9C2 cells were assessed by Western blotting, TUNEL assay, electron microscopy, CCK-8 and caspase 3/7 assay. A rat model of AMI was constructed by ligating the left anterior descending artery. The anti-apoptotic, pro-angiogenic effects of GDF15-EVs treatment, as well as ensuing functional and histological recovery were evaluated. Then, mRNA sequencing was performed to identify the differentially expressed mRNAs after GDF15-EVs treatment.

Results

GDF15-EVs inhibited apoptosis and promoted autophagy in H2O2 injured H9C2 cells. GDF15-EVs effectively decreased the infarct area and enhanced the cardiac function in rats with AMI. Moreover, GDF15-EVs hindered inflammatory cell infiltration, inhibited cell apoptosis, and promoted cardiac angiogenesis in rats with AMI. RNA sequence showed that telomerase reverse transcriptase (TERT) mRNA was upregulated in GDF15-EVs-treated H9C2 cells. AMPK signaling was activated after GDF15-EVs. Silencing TERT impaired the protective effects of GDF15-EVs on H2O2-injured H9C2 cells.

Conclusion

GDF15-EVs could fulfil their protective effects against myocardial injury by upregulating the expression of TERT and activating the AMPK signaling pathway. GDF15-EVs might be exploited to design new therapies for AMI.

Exploring Cutting-Edge Approaches to Potentiate Mesenchymal Stem Cell and Exosome Therapy for Myocardial Infarction

Cardiovascular diseases (CVDs) continue to be a significant global health concern. Many studies have reported promising outcomes from using MSCs and their secreted exosomes in managing various cardiovascular-related diseases like myocardial infarction (MI). MSCs and exosomes have demonstrated considerable potential in promoting regeneration and neovascularization, as well as exerting beneficial effects against apoptosis, remodeling, and inflammation in cases of myocardial infarction. Nonetheless, ensuring the durability and effectiveness of MSCs and exosomes following in vivo transplantation remains a significant concern. Recently, novel methods have emerged to improve their effectiveness and robustness, such as employing preconditioning statuses, modifying MSC and their exosomes, targeted drug delivery with exosomes, biomaterials, and combination therapy. Herein, we summarize the novel approaches that intensify the therapeutic application of MSC and their derived exosomes in treating MI.

Cardiac progenitor cell therapy: mechanisms of action

Heart failure (HF) is an end-stage of many cardiac diseases and one of the main causes of death worldwide. The current management of this disease remains suboptimal. The adult mammalian heart was considered a post-mitotic organ. However, several reports suggest that it may possess modest regenerative potential. Adult cardiac progenitor cells (CPCs), the main players in the cardiac regeneration, constitute, as it may seem, a heterogenous group of cells, which remain quiescent in physiological conditions and become activated after an injury, contributing to cardiomyocytes renewal. They can mediate their beneficial effects through direct differentiation into cardiac cells and activation of resident stem cells but majorly do so through paracrine release of factors. CPCs can secrete cytokines, chemokines, and growth factors as well as exosomes, rich in proteins, lipids and non-coding RNAs, such as miRNAs and YRNAs, which contribute to reparation of myocardium by promoting angiogenesis, cardioprotection, cardiomyogenesis, anti-fibrotic activity, and by immune modulation. Preclinical studies assessing cardiac progenitor cells and cardiac progenitor cells-derived exosomes on damaged myocardium show that administration of cardiac progenitor cells-derived exosomes can mimic effects of cell transplantation. Exosomes may become new promising therapeutic strategy for heart regeneration nevertheless there are still several limitations as to their use in the clinic. Key questions regarding their dosage, safety, specificity, pharmacokinetics, pharmacodynamics and route of administration remain outstanding. There are still gaps in the knowledge on basic biology of exosomes and filling them will bring as closer to translation into clinic.

Stem cell therapy for cardiac regeneration: past, present, and future

Cardiac disorders remain the leading cause of mortality worldwide. Current clinical strategies, including drug therapy, surgical interventions, and organ transplantation offer limited benefits to patients without regenerating the damaged myocardium. Over the past decade, stem cell therapy has generated a keen interest owing to its unique self-renewal and immune privileged characteristics. Furthermore, the ability of stem cells to differentiate into specialized cell types, has made them a popular therapeutic tool against various diseases. This comprehensive review provides an overview of therapeutic potential of different types of stem cells in reference to cardiovascular diseases. Furthermore, it sheds light on the advantages and limitations associated with each cell type. An in-depth analysis of the challenges associated with stem cell research and the hurdles for its clinical translation and their possible solutions have also been elaborated upon. It examines the controversies surrounding embryonic stem cells and the emergence of alternative approaches, such as the use of induced pluripotent stem cells for cardiac therapeutic applications. Overall, this review serves as a valuable resource for researchers, clinicians, and policymakers involved in the field of regenerative medicine, guiding the development of safe and effective stem cell-based therapies to revolutionize patient care.

Augmentation of DNA exonuclease TREX1 in macrophages as a therapy for cardiac ischemic injury

Noncoding RNAs (ncRNAs) are increasingly recognized as bioactive. Here we report the development of TY1, a synthetic ncRNA bioinspired by a naturally-occurring human small Y RNA with immunomodulatory properties. TY1 upregulates TREX1, an exonuclease that rapidly degrades cytosolic DNA. In preclinical models of myocardial infarction (MI) induced by ischemia/reperfusion, TY1 reduced scar size. The cardioprotective effect of TY1 was abrogated by prior depletion of macrophages and mimicked by adoptive transfer of macrophages exposed either to TY1 or TREX1. Inhibition of TREX1 in macrophages blocked TY1 cardioprotection. Consistent with a central role for TREX1, TY1 attenuated DNA damage in the post-MI heart. This novel mechanism-pharmacologic upregulation of TREX1 in macrophages-establishes TY1 as the prototype for a new class of ncRNA drugs with disease-modifying bioactivity.

One Sentence Summary

Upregulation of three prime exonuclease, TREX1, in macrophages enhances tissue repair post myocardial infarction.

The new era of cardiovascular research: revolutionizing cardiovascular research with 3D models in a dish

Cardiovascular research has heavily relied on studies using patient samples and animal models. However, patient studies often miss the data from the crucial early stage of cardiovascular diseases, as obtaining primary tissues at this stage is impracticable. Transgenic animal models can offer some insights into disease mechanisms, although they usually do not fully recapitulate the phenotype of cardiovascular diseases and their progression. In recent years, a promising breakthrough has emerged in the form of in vitro three-dimensional (3D) cardiovascular models utilizing human pluripotent stem cells. These innovative models recreate the intricate 3D structure of the human heart and vessels within a controlled environment. This advancement is pivotal as it addresses the existing gaps in cardiovascular research, allowing scientists to study different stages of cardiovascular diseases and specific drug responses using human-origin models. In this review, we first outline various approaches employed to generate these models. We then comprehensively discuss their applications in studying cardiovascular diseases by providing insights into molecular and cellular changes associated with cardiovascular conditions. Moreover, we highlight the potential of these 3D models serving as a platform for drug testing to assess drug efficacy and safety. Despite their immense potential, challenges persist, particularly in maintaining the complex structure of 3D heart and vessel models and ensuring their function is comparable to real organs. However, overcoming these challenges could revolutionize cardiovascular research. It has the potential to offer comprehensive mechanistic insights into human-specific disease processes, ultimately expediting the development of personalized therapies.

Stem cell therapy for heart failure in the clinics: new perspectives in the era of precision medicine and artificial intelligence

Stem/progenitor cells have been widely evaluated as a promising therapeutic option for heart failure (HF). Numerous clinical trials with stem/progenitor cell-based therapy (SCT) for HF have demonstrated encouraging results, but not without limitations or discrepancies. Recent technological advancements in multiomics, bioinformatics, precision medicine, artificial intelligence (AI), and machine learning (ML) provide new approaches and insights for stem cell research and therapeutic development. Integration of these new technologies into stem/progenitor cell therapy for HF may help address: 1) the technical challenges to obtain reliable and high-quality therapeutic precursor cells, 2) the discrepancies between preclinical and clinical studies, and 3) the personalized selection of optimal therapeutic cell types/populations for individual patients in the context of precision medicine. This review summarizes the current status of SCT for HF in clinics and provides new perspectives on the development of computation-aided SCT in the era of precision medicine and AI/ML.

Circulating GDF11 exacerbates myocardial injury in mice and associates with increased infarct size in humans

AIMS

The heart rejuvenating effects of circulating growth differentiation factor 11 (GDF11), a transforming growth factor-β superfamily member that shares 90% homology with myostatin (MSTN), remains controversial. Here, we aimed to probe the role of GDF11 in acute myocardial infarction (MI), a frequent cause of heart failure and premature death during ageing.

METHODS AND RESULTS

In contrast to endogenous Mstn, myocardial Gdf11 declined during the course of ageing and was particularly reduced following ischaemia/reperfusion (I/R) injury, suggesting a therapeutic potential of GDF11 signalling in MI. Unexpectedly, boosting systemic Gdf11 by recombinant GDF11 delivery (0.1 mg/kg body weight over 30 days) prior to myocardial I/R augmented myocardial infarct size in C57BL/6 mice irrespective of their age, predominantly by accelerating pro-apoptotic signalling. While intrinsic cardioprotective signalling pathways remained unaffected by high circulating GDF11, targeted transcriptomics and immunomapping studies focusing on GDF11-associated downstream targets revealed attenuated Nkx2-5 expression confined to CD105-expressing cells, with pro-apoptotic activity, as assessed by caspase-3 levels, being particularly pronounced in adjacent cells, suggesting an indirect effect. By harnessing a highly specific and validated liquid chromatography-tandem mass spectrometry-based assay, we show that in prospectively recruited patients with MI circulating GDF11 but not MSTN levels incline with age. Moreover, GDF11 levels were particularly elevated in those at high risk for adverse outcomes following the acute event, with circulating GDF11 emerging as an independent predictor of myocardial infarct size, as estimated by standardized peak creatine kinase-MB levels.

CONCLUSION

Our data challenge the initially reported heart rejuvenating effects of circulating GDF11 and suggest that high levels of systemic GDF11 exacerbate myocardial injury in mice and humans alike. Persistently high GDF11 levels during ageing may contribute to the age-dependent loss of cardioprotective mechanisms and thus poor outcomes of elderly patients following acute MI.

A Powerful Tool in the Treatment of Myocardial Ischemia-Reperfusion Injury: Natural and Nanoscale Modified Small Extracellular Vesicles Derived from Mesenchymal Stem Cells

Myocardial ischemia-reperfusion injury (MI/RI) constitutes a pivotal determinant impacting the long-term prognosis of individuals afflicted by ischemic cardiomyopathy subsequent to reperfusion therapy. Stem cells have garnered extensive application within the realm of MI/RI investigation, yielding tangible outcomes. Stem cell therapy encounters certain challenges in its application owing to the complexities associated with stem cell acquisition, a diminished homing rate, and a brief in vivo lifespan. Small extracellular vesicles (sEV) originating from mesenchymal stem cells (MSCs) have been demonstrated to possess the benefits of abundant availability, reduced immunogenicity, and a diminished tumorigenic incidence. They can exert their effects on damaged organs, improving injuries by transporting a lot of constituents, including proteins, RNA, lipid droplets, and more. This phenomenon has garnered substantial attention in the context of MI/RI treatment. Simultaneously, MSC-derived sEV (MSC-sEV) can exhibit enhanced therapeutic advantages through bioengineering modifications, biomaterial incorporation, and natural drug interventions. Within this discourse, we shall appraise the utilization of MSC-sEV and their derivatives in the context of MI/RI treatment, aiming to offer valuable insights for future research endeavors related to MI/RI.

Lack of cardiac benefit after intramyocardial or intravenous injection of mesenchymal stem cell-derived extracellular vesicles supports the need for optimized cardiac delivery

Aim

To determine the differences in improvement in cardiac function by intramyocardial (IM) vs. intravenous (IV) injection of human bone mesenchymal stem cell-derived extracellular vesicles (HBMSC-EV) after acute MI.

Methods

FVB mice underwent acute MI via left anterior descending coronary artery ligation and subsequent injection of: (1) IM saline control; (2) IM HBMSC-EV; (3) IV saline control; and (4) IV HBMSC-EV. Cardiac function was evaluated with weekly postoperative echocardiography. On postoperative day 28, the mice were euthanized, and the heart, lungs, liver, spleen, and kidneys were harvested. Given previous studies showing HBMSC-EV hepatic uptake after IV injection, the liver was evaluated for changes in inflammation, fibrosis, and proliferation.

Results

On postoperative day 28, there were no significant differences in left ventricular ejection fraction (P = 0.6151), fractional shortening (P = 0.1135), or anterior border zone fibrosis (P = 0.6333) in any of the experimental groups. Interestingly, there was a strong trend demonstrating improvement in infarct size on fibrosis staining, which did not reach significance (P = 0.05620). There were no differences in hepatic inflammation, fibrosis, and proliferation.

Conclusions

Although there was a trend in the improvement in infarct size, a single-dose administration of neither IM nor IV injection of HBMSC-EV resulted in significant improvement in post-MI cardiac function. A major limitation of this study is the lack of trials determining the optimal dose of HBMSC-EV needed in this model. However, the current study demonstrates that future studies are required to either optimize administration or bioengineer HBMSC-EV with cardiac-homing properties.

Tumor Necrosis Factor-Alpha Induces Proangiogenic Profiling of Cardiosphere-Derived Cell Secretome and Increases Its Ability to Stimulate Angiogenic Properties of Endothelial Cells

Ischemic heart disease and its complications, such as myocardial infarction and heart failure, are the leading causes of death in modern society. The adult heart innately lacks the capacity to regenerate the damaged myocardium after ischemic injury. Multiple lines of evidence indicated that stem-cell-based transplantation is one of the most promising treatments for damaged myocardial tissue. Different kinds of stem cells have their advantages for treating ischemic heart disease. One facet of their mechanism is the paracrine effect of the transplanted cells. Particularly promising are stem cells derived from cardiac tissue per se, referred to as cardiosphere-derived cells (CDCs), whose therapeutic effect is mediated by the paracrine mechanism through secretion of multiple bioactive molecules providing immunomodulatory, angiogenic, anti-fibrotic, and anti-inflammatory effects. Although secretome-based therapies are increasingly being used to treat various cardiac pathologies, many obstacles remain because of population heterogeneity, insufficient understanding of potential modulating compounds, and the principles of secretome regulation, which greatly limit the feasibility of this technology. In addition, components of the inflammatory microenvironment in ischemic myocardium may influence the secretome content of transplanted CDCs, thus altering the efficacy of cell therapy. In this work, we studied how Tumor necrosis factor alpha (TNFa), as a key component of the pro-inflammatory microenvironment in damaged myocardium from ischemic injury and heart failure, may affect the secretome content of CDCs and their angiogenic properties. We have shown for the first time that TNFa may act as a promising compound modulating the CDC secretome, which induces its profiling to enhance proangiogenic effects on endothelial cells. These results allow us to elucidate the underlying mechanisms of the impact of the inflammatory microenvironment on transplanted CDCs and may contribute to the optimization of CDC efficiency and the development of the technology for producing the CDC secretome with enhanced proangiogenic properties for cell-free therapy.

Extracellular vesicles derived from different tissues attenuate cardiac dysfunction in murine MI models

BACKGROUND

Extracellular vesicles (EVs) derived from various cell sources exert cardioprotective effects during cardiac ischemic injury. Our previous study confirmed that EVs derived from ischemic-reperfusion injured heart tissue aggravated cardiac inflammation and dysfunction. However, the role of EVs derived from normal cardiac tissue in myocardial ischemic injury remains elusive.

RESULTS

In the present study, normal heart-derived EVs (cEVs) and kidney-derived EVs (nEVs) were isolated and intramyocardially injected into mice after myocardial infarction (MI). We demonstrated that administration of both cEVs and nEVs significantly improved cardiac function, reduced the scar size, and alleviated inflammatory infiltration into the heart. In addition, cardiomyocyte apoptosis was inhibited, whereas angiogenesis was enhanced in the hearts receiving cEVs or nEVs treatment. Moreover, intramyocardial injection of cEVs displayed much better cardiac protective efficacy than nEVs in murine MI models. RNA-seq and protein-protein interaction (PPI) network analysis revealed the protective mRNA clusters in both cEVs and nEVs. These mRNAs were involved in multiple signaling pathways, which may synergistically orchestrate to prevent the heart from further damage post MI.

CONCLUSIONS

Collectively, our results indicated that EVs derived from normal heart tissue may represent a promising strategy for cardiac protection in ischemic heart diseases.

Stem Cell-Based Therapy and Cell-Free Therapy as an Alternative Approach for Cardiac Regeneration

The World Health Organization reports that cardiovascular diseases (CVDs) represent 32% of all global deaths. The ineffectiveness of conventional therapies in CVDs encourages the development of novel, minimally invasive therapeutic strategies for the healing and regeneration of damaged tissue. The self-renewal capacity, multilineage differentiation, lack of immunogenicity, and immunosuppressive properties of mesenchymal stem cells (MSCs) make them a promising option for CVDs. However, growing evidence suggests that myocardial regeneration occurs through paracrine factors and extracellular vesicle (EV) secretion, rather than through differentiation into cardiomyocytes. Research shows that stem cells secrete or surface-shed into their culture media various cytokines, chemokines, growth factors, anti-inflammatory factors, and EVs, which constitute an MSC-conditioned medium (MSC-CM) or the secretome. The use of MSC-CM enhances cardiac repair through resident heart cell differentiation, proliferation, scar mass reduction, a decrease in infarct wall thickness, and cardiac function improvement comparable to MSCs without their side effects. This review highlights the limitations and benefits of therapies based on stem cells and their secretome as an innovative treatment of CVDs.

Challenges and future scope of exosomes in the treatment of cardiovascular diseases

Exosomes are nanosized vesicles that carry biologically diverse molecules for intercellular communication. Researchers have been trying to engineer exosomes for therapeutic purposes by using different approaches to deliver biologically active molecules to the various target cells efficiently. Recent technological advances may allow the biodistribution and pharmacokinetics of exosomes to be modified to meet scientific needs with respect to specific diseases. However, it is essential to determine an exosome's optimal dosage and potential side effects before its clinical use. Significant breakthroughs have been made in recent decades concerning exosome labelling and imaging techniques. These tools provide in situ monitoring of exosome biodistribution and pharmacokinetics and pinpoint targetability. However, because exosomes are nanometres in size and vary significantly in contents, a deeper understanding is required to ensure accurate monitoring before they can be applied in clinical settings. Different research groups have established different approaches to elucidate the roles of exosomes and visualize their spatial properties. This review covers current and emerging strategies for in vivo and in vitro exosome imaging and tracking for potential studies.

Customized Loading of microRNA-126 to Small Extracellular Vesicle-Derived Vehicles Improves Cardiac Function after Myocardial Infarction

Small extracellular vesicles (sEVs) are promising for cell-based cardiac repair after myocardial infarction. These sEVs encapsulate potent cargo, including microRNAs (miRs), within a bilayer membrane that aids sEV uptake when administered to cells. However, despite their efficacy, sEV therapies are limited by inconsistencies in the sEV release from parent cells and variability in cargo encapsulation. Synthetic sEV mimics with artificial bilayer membranes allow for cargo control but suffer poor stability and rapid clearance when administered in vivo. Here, we developed an sEV-like vehicle (ELV) using an electroporation technique, building upon our previously published work, and investigated the potency of delivering electroporated ELVs with pro-angiogenic miR-126 both in vitro and in vivo to a rat model of ischemia-reperfusion. We show that electroporated miR-126+ ELVs improve tube formation parameters when administered to 2D cultures of cardiac endothelial cells and improve both echocardiographic and histological parameters when delivered to a rat left ventricle after ischemia reperfusion injury. This work emphasizes the value of using electroporated ELVs as vehicles for delivery of select miR cargo for cardiac repair.

Modular Bioorthogonal Lipid Nanoparticle Modification Platforms for Cardiac Homing

Lipid nanoparticles (LNPs) are becoming widely adopted as vectors for the delivery of therapeutic payloads but generally lack intrinsic tissue-homing properties. These extracellular vesicle (EV) mimetics can be targeted toward the liver, lung, or spleen via charge modification of their lipid headgroups. Homing to other tissues has only been achieved via covalent surface modification strategies using small-molecule ligands, peptides, or monoclonal antibodies─methods that are challenging to couple with large-scale manufacturing. Herein, we design a novel modular artificial membrane-binding protein (AMBP) platform for the modification of LNPs postformation. The system is composed of two protein modules that can be readily coupled using bioorthogonal chemistry to yield the AMBP. The first is a membrane anchor module comprising a supercharged green fluorescent protein (scGFP) electrostatically conjugated to a dynamic polymer surfactant corona. The second is a functional module containing a cardiac tissue fibronectin homing sequence from the bacterial adhesin CshA. We demonstrate that LNPs modified using the AMBP exhibit a 20-fold increase in uptake by fibronectin-rich C2C12 cells under static conditions and a 10-fold increase under physiologically relevant shear stresses, with no loss of cell viability. Moreover, we show targeted localization of the AMBP-modified LNPs in zebrafish hearts, highlighting their therapeutic potential as a vector for the treatment of cardiac disease and, more generally, as a smart vector.

Vascular calcification: from the perspective of crosstalk

Vascular calcification (VC) is highly correlated with cardiovascular disease morbidity and mortality, but anti-VC treatment remains an area to be tackled due to the ill-defined molecular mechanisms. Regardless of the type of VC, it does not depend on a single cell but involves multi-cells/organs to form a complex cellular communication network through the vascular microenvironment to participate in the occurrence and development of VC. Therefore, focusing only on the direct effect of pathological factors on vascular smooth muscle cells (VSMCs) tends to overlook the combined effect of other cells and VSMCs, including VSMCs-VSMCs, ECs-VMSCs, Macrophages-VSMCs, etc. Extracellular vesicles (EVs) are a collective term for tiny vesicles with a membrane structure that are actively secreted by cells, and almost all cells secrete EVs. EVs docked on the surface of receptor cells can directly mediate signal transduction or transfer their contents into the cell to elicit a functional response from the receptor cells. They have been proven to participate in the VC process and have also shown attractive therapeutic prospects. Based on the advantages of EVs and the ability to be detected in body fluids, they may become a novel therapeutic agent, drug delivery vehicle, diagnostic and prognostic biomarker, and potential therapeutic target in the future. This review focuses on the new insight into VC molecular mechanisms from the perspective of crosstalk, summarizes how multi-cells/organs interactions communicate via EVs to regulate VC and the emerging potential of EVs as therapeutic methods in VC. We also summarize preclinical experiments on crosstalk-based and the current state of clinical studies on VC-related measures.

Mechanically induced pyroptosis enhances cardiosphere oxidative stress resistance and metabolism for myocardial infarction therapy

Current approaches in myocardial infarction treatment are limited by low cellular oxidative stress resistance, reducing the long-term survival of therapeutic cells. Here we develop a liquid-crystal substrate with unique surface properties and mechanical responsiveness to produce size-controllable cardiospheres that undergo pyroptosis to improve cellular bioactivities and resistance to oxidative stress. We perform RNA sequencing and study cell metabolism to reveal increased metabolic levels and improved mitochondrial function in the preconditioned cardiospheres. We test therapeutic outcomes in a rat model of myocardial infarction to show that cardiospheres improve long-term cardiac function, promote angiogenesis and reduce cardiac remodeling during the 3-month observation. Overall, this study presents a promising and effective system for preparing a large quantity of functional cardiospheres, showcasing potential for clinical application.

Stem cell Derived Extracellular Vesicles to Alleviate ischemia-reperfusion Injury of Transplantable Organs. A Systematic Review

BACKGROUND

The possible beneficial effects of stem cell-derived EV on ischemia-reperfusion injury (IRI) in organ transplantation have been frequently investigated; however, the source of EV, as well as the methods of isolation and administration vary widely. We conducted a systematic review to summarize current pre-clinical evidence on stem cell-derived EV therapy for IRI of transplantable organs.

METHODS

PubMed, Embase and Web of Science were searched from inception until August 19th, 2022, for studies on stem cell-derived EV therapy for IRI after heart, kidney, liver, pancreas, lung and intestine transplantation. The Systematic Review Center for Laboratory animal Experiments (SYRCLE) guidelines were followed to assess potential risk of bias.

RESULTS

The search yielded 4153 unique articles, of which 96 were retained. We identified 32 studies on cardiac IRI, 38 studies on renal IRI, 21 studies on liver IRI, four studies on lung IRI and one study on intestinal IRI. Most studies used rodent models of transient ischemic injury followed by in situ reperfusion. In all studies, EV therapy was associated with improved outcome albeit to a variable degree. EV-therapy reduced organ injury and improved function while displaying anti-inflammatory-, immunomodulatory- and pro-regenerative properties.

CONCLUSION

A multitude of animal studies support the potential of stem cell-derived EV-therapy to alleviate IRI after solid organ transplantation but suffer from low reporting quality and wide methodological variability. Future studies should focus on determining optimal stem cell source, dosage, and timing of treatment, as well as long-term efficacy in transplant models.

[Cardiac progenitor cells-derived exosomes alleviate myocardial injury by regulating Treg cell differentiation through the mTOR pathway in mice with myocardial infarction]

OBJECTIVE

To investigate the effect of cardiac progenitor cells-derived exosomes (CPCs-Exo) on Treg differentiation in mice with myocardial infarction (MI).

METHODS

Mouse models of MI established by ligation of the left anterior descending coronary artery (LAD) were treated with CPCs-Exos, and naive CD4+T cells were isolated from the spleen of the mice and divided into control group, CD4+T cell activation group (CD3+CD28), CPCs-Exos stimulation group (CD3+CD28+CPCs-Exos), mTOR activator group (CD3+CD28+CPCs-Exos+mTOR activator) and mTOR inhibitor group (CD3+CD28+CPCs-Exos+mTOR inhibitor). Western blotting was used to detect the expression levels of mTOR and p-mTOR in the treated cells. Flow cytometry was used to analyze the percentages of Treg and CD4+IL-10+T cells. The infarct size of the mice were measured with 2, 3, 5-triphenyltetrazole chloride (TTC) staining, and serum levels of LDH and CK-MB were detected using an automatic biochemical analyzer.

RESULTS

Compared with the control group, the mouse models of MI showed significantly increased release of LDH (P<0.001) and CK-MB (P=0.0002) and increased percentages of Treg and CD4+IL-10+T cells. Treatment with CPC-Exos effectively reduced the MI area and lowered serum levels of LDH (P=0.003) and CK-MB (P=0.003) and the percentages of Tregs (P=0.001) and CD4+IL-10+T cells (P=0.004) in the MI mouse models. In the isolated CD4+T cells, CPCsExos treatment significantly up-regulated the percentages of Treg (P=0.01) and CD4+IL-10+ T cells (P=0.004) and increased the expression of mTOR (P=0.009) and p-mTOR (P=0.009), and these effects could be further enhanced by the mTOR activator but obviously attenuated by the mTOR inhibitor.

CONCLUSION

CPCs-Exos promotes the differentiation of Treg in mice with MI by modulating the mTOR signaling pathway.

Advances in the study of exosomes derived from mesenchymal stem cells and cardiac cells for the treatment of myocardial infarction

Acute myocardial infarction has long been the leading cause of death in coronary heart disease, which is characterized by irreversible cardiomyocyte death and restricted blood supply. Conventional reperfusion therapy can further aggravate myocardial injury. Stem cell therapy, especially with mesenchymal stem cells (MSCs), has emerged as a promising approach to promote cardiac repair and improve cardiac function. MSCs may induce these effects by secreting exosomes containing therapeutically active RNA, proteins and lipids. Notably, normal cardiac function depends on intracardiac paracrine signaling via exosomes, and exosomes secreted by cardiac cells can partially reflect changes in the heart during disease, so analyzing these vesicles may provide valuable insights into the pathology of myocardial infarction as well as guide the development of new treatments. The present review examines how exosomes produced by MSCs and cardiac cells may influence injury after myocardial infarction and serve as therapies against such injury. Video Abstract.

Engineering exosomes and their application in cardiovascular field: Bibliometric analysis from 2002 to 2022

Cardiovascular disease (CVD) is the leading cause of death around the world, warranting an increasing number of studies for its treatment. Among all of its therapeutical strategies, engineered exosomes are attracting growing attention due to their excellent biocompatibility, non-immunogenicity, and favorable plasticity. Despite its increasing popularity, there is yet to be a bibliometric analysis regarding the application of exosomes in CVD treatment. Therefore, the present study assessed the current trends in engineered exosomes in treating CVD by conducting a bibliometric analysis. All associated literatures published between years 2002-2022 were collected, through the Web of Science Core Collection. Our results showed that related studies robustly increased in 2020, followed by a gradual increase from 2020 to 2022, indicating that this field attracted growing attention. Additionally, we described critical network of countries, institutions, authors, top-cited references, and keywords. The present bibliometric study provides systematic observations on engineering exosomes in treating CVD, reveals potential challenges and future direction for additional studies, and may inspire more researchers to commit to investigating treatments for CVD.

The origin, progress, and application of cell-based cardiac regeneration therapy

Cardiovascular disease (CVD) has become a severe threat to human health, with morbidity and mortality increasing yearly and gradually becoming younger. When the disease progresses to the middle and late stages, the loss of a large number of cardiomyocytes is irreparable to the body itself, and clinical drug therapy and mechanical support therapy cannot reverse the development of the disease. To explore the source of regenerated myocardium in model animals with the ability of heart regeneration through lineage tracing and other methods, and develop a new alternative therapy for CVDs, namely cell therapy. It directly compensates for cardiomyocyte proliferation through adult stem cell differentiation or cell reprogramming, which indirectly promotes cardiomyocyte proliferation through non-cardiomyocyte paracrine, to play a role in heart repair and regeneration. This review comprehensively summarizes the origin of newly generated cardiomyocytes, the research progress of cardiac regeneration based on cell therapy, the opportunity and development of cardiac regeneration in the context of bioengineering, and the clinical application of cell therapy in ischemic diseases.

Inhalable CAR-T cell-derived exosomes as paclitaxel carriers for treating lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) is a worldwide health threat with high annual morbidity and mortality. Chemotherapeutic drugs such as paclitaxel (PTX) have been widely applied clinically. However, systemic toxicity due to the non-specific circulation of PTX often leads to multi-organ damage, including to the liver and kidney. Thus, it is necessary to develop a novel strategy to enhance the targeted antitumor effects of PTX.

METHODS

Here, we engineered exosomes derived from T cells expressing the chimeric antigen receptor (CAR-Exos), which targeted mesothelin (MSLN)-expressing Lewis lung cancer (MSLN-LLC) through the anti-MSLN single-chain variable fragment (scFv) of CAR-Exos. PTX was encapsulated into CAR-Exos (PTX@CAR-Exos) and administered via inhalation to an orthotopic lung cancer mouse model.

RESULTS

Inhaled PTX@CAR-Exos accumulated within the tumor area, reduced tumor size, and prolonged survival with little toxicity. In addition, PTX@CAR-Exos reprogrammed the tumor microenvironment and reversed the immunosuppression, which was attributed to infiltrating CD8⁺ T cells and elevated IFN-γ and TNF-α levels.

CONCLUSIONS

Our study provides a nanovesicle-based delivery platform to promote the efficacy of chemotherapeutic drugs with fewer side effects. This novel strategy may ameliorate the present obstacles to the clinical treatment of lung cancer.

Extracellular vesicles: emerging roles, biomarkers and therapeutic strategies in fibrotic diseases

Extracellular vesicles (EVs), a cluster of cell-secreted lipid bilayer nanoscale particles, universally exist in body fluids, as well as cell and tissue culture supernatants. Over the past years, increasing attention have been paid to the important role of EVs as effective intercellular communicators in fibrotic diseases. Notably, EV cargos, including proteins, lipids, nucleic acids, and metabolites, are reported to be disease-specific and can even contribute to fibrosis pathology. Thus, EVs are considered as effective biomarkers for disease diagnosis and prognosis. Emerging evidence shows that EVs derived from stem/progenitor cells have great prospects for cell-free therapy in various preclinical models of fibrotic diseases and engineered EVs can improve the targeting and effectiveness of their treatment. In this review, we will focus on the biological functions and mechanisms of EVs in the fibrotic diseases, as well as their potential as novel biomarkers and therapeutic strategies.

Intrapericardial long non-coding RNA-Tcf21 antisense RNA inducing demethylation administration promotes cardiac repair

AIMS

Epicardium and epicardium-derived cells are critical players in myocardial fibrosis. Mesenchymal stem cell-derived extracellular vesicles (EVs) have been studied for cardiac repair to improve cardiac remodelling, but the actual mechanisms remain elusive. The aim of this study is to investigate the mechanisms of EV therapy for improving cardiac remodelling and develop a promising treatment addressing myocardial fibrosis.

METHODS AND RESULTS

Extracellular vesicles were intrapericardially injected for mice myocardial infarction treatment. RNA-seq, in vitro gain- and loss-of-function experiments, and in vivo studies were performed to identify targets that can be used for myocardial fibrosis treatment. Afterward, a lipid nanoparticle-based long non-coding RNA (lncRNA) therapy was prepared for mouse and porcine models of myocardial infarction treatment. Intrapericardial injection of EVs improved adverse myocardial remodelling in mouse models of myocardial infarction. Mechanistically, Tcf21 was identified as a potential target to improve cardiac remodelling. Loss of Tcf21 function in epicardium-derived cells caused increased myofibroblast differentiation, whereas forced Tcf21 overexpression suppressed transforming growth factor-β signalling and myofibroblast differentiation. LncRNA-Tcf21 antisense RNA inducing demethylation (TARID) that enriched in EVs was identified to up-regulate Tcf21 expression. Formulated lncRNA-TARID-laden lipid nanoparticles up-regulated Tcf21 expression in epicardium-derived cells and improved cardiac function and histology in mouse and porcine models of myocardial infarction.

CONCLUSION

This study identified Tcf21 as a critical target for improving cardiac fibrosis. Up-regulating Tcf21 by using lncRNA-TARID-laden lipid nanoparticles could be a promising way to treat myocardial fibrosis. This study established novel mechanisms underlying EV therapy for improving adverse remodelling and proposed a lncRNA therapy for cardiac fibrosis.

Extracellular vesicles engineering by silicates-activated endothelial progenitor cells for myocardial infarction treatment in male mice

Extracellular vesicles have shown good potential in disease treatments including ischemic injury such as myocardial infarction. However, the efficient production of highly active extracellular vesicles is one of the critical limitations for their clinical applications. Here, we demonstrate a biomaterial-based approach to prepare high amounts of extracellular vesicles with high bioactivity from endothelial progenitor cells (EPCs) by stimulation with silicate ions derived from bioactive silicate ceramics. We further show that hydrogel microspheres containing engineered extracellular vesicles are highly effective in the treatment of myocardial infarction in male mice by significantly enhancing angiogenesis. This therapeutic effect is attributed to significantly enhanced revascularization by the high content of miR-126a-3p and angiogenic factors such as VEGF and SDF-1, CXCR4 and eNOS in engineered extracellular vesicles, which not only activate endothelial cells but also recruit EPCs from the circulatory system.

Transplantation of Exercise-Induced Extracellular Vesicles as a Promising Therapeutic Approach in Ischemic Stroke

Clinical evidence affirms physical exercise is effective in preventive and rehabilitation approaches for ischemic stroke. This sustainable efficacy is independent of cardiovascular risk factors and associates substantial reprogramming in circulating extracellular vesicles (EVs). The intricate journey of pluripotent exercise-induced EVs from parental cells to the whole-body and infiltration to cerebrovascular entity offers several mechanisms to reduce stroke incidence and injury or accelerate the subsequent recovery. This review delineates the potential roles of EVs as prospective effectors of exercise. The candidate miRNA and peptide cargo of exercise-induced EVs with both atheroprotective and neuroprotective characteristics are discussed, along with their presumed targets and pathway interactions. The existing literature provides solid ground to hypothesize that the rich vesicles link exercise to stroke prevention and rehabilitation. However, there are several open questions about the exercise stressors which may optimally regulate EVs kinetic and boost brain mitochondrial adaptations. This review represents a novel perspective on achieving brain fitness against stroke through transplantation of multi-potential EVs generated by multi-parental cells, which is exceptionally reachable in an exercising body.

Endothelial activation impairs the function of small extracellular vesicles

Small extracellular vesicles are nanosized vesicles (30–200 nm) that can ferry proteins, nucleic acids, and lipids between cells and therefore, have significant potential as biomarkers, drug delivery tools or therapeutic agents. SEVs of endothelial origin have been shown to -among other functions-reduce in vitro ischemia/reperfusion (I/R) injury in cardiomyocytes, but whether a pro-inflammatory state of the endothelium impairs the functionality of these SEVs remains to be elucidated. To test this, human umbilical vein endothelial cells cells were treated with TNF-α 10 ng/mL and the expression of the pro-inflammatory parameters VCAM-1, ICAM-1 and eNOS were determined by Western blot. SEVs were isolated from endothelial cells treated with or without TNF-α 10 ng/mL using size exclusion chromatography. The size and concentration of SEVs was measured by Nanoparticle Tracking Analysis. The expression of the surface marker CD81 was determined by immunoassay, whereas their morphology was assessed by electron microscopy. The function of endothelial SEVs was assessed by evaluating their cardioprotective effect in an ex vivo model of global I/R using isolated hearts from adult C57BL/6 mice. Treatment of HUVECs with TNF-α induced the expression of VCAM-1 and ICAM-1, whereas eNOS levels were decreased. TNF-α did not affect the production, size, morphology, or expression of CD81. SEVs significantly reduced the infarct size as compared with untreated mice hearts, but SEVs isolated from TNF-α treated cells were unable to achieve this effect. Therefore, a pro-inflammatory state induced by TNF-α does not alter the production of endothelial SEVs but impairs their function in the setting of I/R injury.

Apigenin reduces the suppressive effect of exosomes derived from irritable bowel syndrome patients on the autophagy of human colon epithelial cells by promoting ATG14

BACKGROUND

Inflammatory bowel disease (IBS) is a chronic disorder of the gastrointestinal tract. Exosomes have been involved in various pathological processes including IBS. Apigenin has been reported to suppress inflammatory bowel disease (IBS). However, the regulatory roles of exosomes derived from IBS patients (IBS-exos) on human colon epithelial cells are still unclear.

METHODS

Exosomes were collected from IBS patients (IBS-exos) and co-cultured with CACO-2 cells. Apigenin was used to treat IBS-exos-treated CACO-2 cells. By exploring the public data bank, we figured out the regulators control the autophagy of CACO-2 cells.

RESULTS

Administration of apigenin dose-dependently abolished the inhibitory effect of IBS-exo on the autophagy of CACO-2 cells. A mechanistic study showed that miR-148b-3p bound to 3'UTR to suppress ATG14 and decrease autophagy. Moreover, results suggested that ATG14 overexpression promoted the autophagy of CACO-2 cells in the presence of miR-148b-3p mimic.

CONCLUSION

The current study showed that apigenin dose-dependently abolished the inhibitory effect of IBS-exo on CACO-2 cell autophagy by regulating miR-148b-3p/ATG14 signaling.

Visualization of cardiac uptake of bone marrow mesenchymal stem cell-derived extracellular vesicles after intramyocardial or intravenous injection in murine myocardial infarction

In animal models, human bone marrow mesenchymal stem cell-derived extracellular vesicles (MSC-EV) have been found to have beneficial effects in cardiovascular disease, but only when administered via intramyocardial injection. The biodistribution of either intravenous or intramyocardial injection of MSC-EV in the presence of myocardial injury is uncharacterized at this time. We hypothesized that intramyocardial injection will ensure delivery of MSC-EV to the ischemic myocardium, while intravenous injection will not. Human bone marrow mesenchymal stem cells were cultured and the MSC-EV were isolated and characterized. The MSC-EVs were then labeled with DiD lipid dye. FVB mice with normal cardiac function underwent left coronary artery ligation followed by either peri-infarct intramyocardial or tail vein injection of 3*106 or 2*109 particles of DiD-labeled MSC-EV or a DiD-saline control. The heart, lungs, liver, spleen and kidneys were harvested 2 h post-injection and were submitted for fluorescent molecular tomography imaging. Myocardial uptake of MSC-EV was only visualized after intramyocardial injection of 2*109 MSC-EV particles (p = 0.01) compared to control, and there were no differences in cardiac fluorescence after tail vein injection of MSC-EV (p = 0.5). There was no significantly detectable MSC-EV uptake in other organs after intramyocardial injection. After tail vein injection of 2*109 particles of MSC-EV, the liver (p = 0.02) and spleen (p = 0.04) appeared to have diffuse MSC-EV uptake compared to controls. Even in the presence of myocardial injury, only intramyocardial but not intravenous administration resulted in detectable levels of MSC-EV in the ischemic myocardium. This study confirms the role for intramyocardial injection in maximal and effective delivery of MSC-EV. Our ongoing studies aimed at developing bioengineered MSC-EV for targeted delivery to the heart may render MSC-EV clinically applicable for cardiovascular disease.

Fibrin-Enriched Cardiac Extracellular Matrix Hydrogel Promotes In Vitro Angiogenesis

Angiogenesis is essential for cardiac repair after myocardial infarction. Promoting angiogenesis has been demonstrated as an effective approach for myocardial infarction treatment. Several different strategies for inducing myocardial angiogenesis have been explored, including exogenous delivery of angiogenic genes, proteins, microRNAs, cells, and extracellular vesicles. Various types of injectable hydrogels have been investigated for cardiac tissue repair. One of the most promising injectable hydrogels in cardiac regeneration is a cardiac extracellular matrix hydrogel that is derived from decellularized porcine myocardium. It can be delivered minimally invasively via transendocardial delivery. The safety and efficacy of cardiac extracellular matrix hydrogels have been shown in small and large animal myocardial infarction models as well as clinical trials. The main mechanisms underlying the therapeutic benefits of cardiac extracellular matrix hydrogels have been elucidated and involved in the modulation of the immune response, downregulation of pathways related to heart failure progression and fibrosis, upregulation of genes important for cardiac muscle contraction, and enhancing cardiomyocyte differentiation and maturation from stem cells. However, no potent capillary network formation induced by cardiac extracellular matrix hydrogels has been reported. In this study, we tested the feasibility of incorporating a fibrin matrix into cardiac extracellular matrix hydrogels to improve the angiogenic properties of the hydrogel. Our in vitro results demonstrate that fibrin-enriched cardiac extracellular matrix hydrogels can induce robust endothelial cell tube formation from human umbilical vein endothelial cells and promote the sprouting of human mesenchymal stem cell spheroids. The obtained information from this study is very critical toward the future in vivo evaluation of fibrin-enriched cardiac extracellular matrix hydrogels in promoting myocardial angiogenesis.

Current challenges and future directions for engineering extracellular vesicles for heart, lung, blood and sleep diseases

Extracellular vesicles (EVs) carry diverse bioactive components including nucleic acids, proteins, lipids and metabolites that play versatile roles in intercellular and interorgan communication. The capability to modulate their stability, tissue-specific targeting and cargo render EVs as promising nanotherapeutics for treating heart, lung, blood and sleep (HLBS) diseases. However, current limitations in large-scale manufacturing of therapeutic-grade EVs, and knowledge gaps in EV biogenesis and heterogeneity pose significant challenges in their clinical application as diagnostics or therapeutics for HLBS diseases. To address these challenges, a strategic workshop with multidisciplinary experts in EV biology and U.S. Food and Drug Administration (USFDA) officials was convened by the National Heart, Lung and Blood Institute. The presentations and discussions were focused on summarizing the current state of science and technology for engineering therapeutic EVs for HLBS diseases, identifying critical knowledge gaps and regulatory challenges and suggesting potential solutions to promulgate translation of therapeutic EVs to the clinic. Benchmarks to meet the critical quality attributes set by the USFDA for other cell-based therapeutics were discussed. Development of novel strategies and approaches for scaling-up EV production and the quality control/quality analysis (QC/QA) of EV-based therapeutics were recognized as the necessary milestones for future investigations.