Targeting regenerative exosomes to myocardial infarction using cardiac homing peptide

Light-Activated Gold-Selenium Core-Shell Nanocomposites with NIR-II Photoacoustic Imaging Performances for Heart-Targeted Repair

Mitochondrial dysfunction and oxidative damage represent important pathological mechanisms of myocardial ischemia-reperfusion injury (MI/RI). Searching for potential antioxidant agents to attenuate MI/RI is of great significance in clinic. Herein, gold-selenium core-shell nanostructures (AS-I/S NCs) with good near-infrared (NIR)-II photoacoustic imaging were designed for MI/RI treatment. The AS-I/S NCs after ischemic myocardium-targeted peptide (IMTP) and mitochondrial-targeted antioxidant peptide SS31 modification achieved cardiomyocytes-targeted cellular uptake and enhanced antioxidant ability and significantly inhibited oxygen-glucose deprivation-recovery (OGD/R)-induced cardiotoxicity of H9c2 cells by inhibiting the depletion of mitochondrial membrane potential (MMP) and restoring ATP synthase activity. Furthermore, the AS-I/S NCs after SS31 modification achieved mitochondria-targeted inhibition of reactive oxygen species (ROS) and subsequently attenuated oxidative damage in OGD/R-treated H9c2 cells by inhibition of apoptosis and oxidative damage, regulation of MAPKs and PI3K/AKT pathways. The in vivo AS-I/S NCs administration dramatically improved myocardial functions and angiogenesis and inhibited myocardial fibrosis through inhibiting myocardial apoptosis and oxidative damage in MI/RI of rats. Importantly, the AS-I/S NCs showed good safety and biocompatibility in vivo. Therefore, our findings validated the rational design that mitochondria-targeted selenium-gold nanocomposites could attenuate MI/RI of rats by inhibiting ROS-mediated oxidative damage and regulating MAPKs and PI3K/AKT pathways, which could be a potential therapy for the MI/RI treatment.

Illuminating the Molecular Intricacies of Exosomes and ncRNAs in Cardiovascular Diseases: Prospective Therapeutic and Biomarker Potential

Cardiovascular diseases (CVDs) are one of the leading causes of death worldwide. Accumulating evidences have highlighted the importance of exosomes and non-coding RNAs (ncRNAs) in cardiac physiology and pathology. It is in general consensus that exosomes and ncRNAs play a crucial role in the maintenance of normal cellular function; and interestingly it is envisaged that their potential as prospective therapeutic candidates and biomarkers are increasing rapidly. Considering all these aspects, this review provides a comprehensive overview of the recent understanding of exosomes and ncRNAs in CVDs. We provide a great deal of discussion regarding their role in the cardiovascular system, together with providing a glimpse of ideas regarding strategies exploited to harness their potential as a therapeutic intervention and prospective biomarker against CVDs. Thus, it could be envisaged that a thorough understanding of the intricacies related to exosomes and ncRNA would seemingly allow their full exploration and may lead clinical settings to become a reality in near future.

Scalable Generation of Nanovesicles from Human-Induced Pluripotent Stem Cells for Cardiac Repair

Extracellular vesicles (EVs) from stem cells have shown significant therapeutic potential to repair injured cardiac tissues and regulate pathological fibrosis. However, scalable generation of stem cells and derived EVs for clinical utility remains a huge technical challenge. Here, we report a rapid size-based extrusion strategy to generate EV-like membranous nanovesicles (NVs) from easily sourced human iPSCs in large quantities (yield 900× natural EVs). NVs isolated using density-gradient separation (buoyant density 1.13 g/mL) are spherical in shape and morphologically intact and readily internalised by human cardiomyocytes, primary cardiac fibroblasts, and endothelial cells. NVs captured the dynamic proteome of parental cells and include pluripotency markers (LIN28A, OCT4) and regulators of cardiac repair processes, including tissue repair (GJA1, HSP20/27/70, HMGB1), wound healing (FLNA, MYH9, ACTC1, ILK), stress response/translation initiation (eIF2S1/S2/S3/B4), hypoxia response (HMOX2, HSP90, GNB1), and extracellular matrix organization (ITGA6, MFGE8, ITGB1). Functionally, NVs significantly promoted tubule formation of endothelial cells (angiogenesis) (p < 0.05) and survival of cardiomyocytes exposed to low oxygen conditions (hypoxia) (p < 0.0001), as well as attenuated TGF-β mediated activation of cardiac fibroblasts (p < 0.0001). Quantitative proteome profiling of target cell proteome following NV treatments revealed upregulation of angiogenic proteins (MFGE8, MYH10, VDAC2) in endothelial cells and pro-survival proteins (CNN2, THBS1, IGF2R) in cardiomyocytes. In contrast, NVs attenuated TGF-β-driven extracellular matrix remodelling capacity in cardiac fibroblasts (ACTN1, COL1A1/2/4A2/12A1, ITGA1/11, THBS1). This study presents a scalable approach to generating functional NVs for cardiac repair.

Precise dapagliflozin delivery by cardiac homing peptide functionalized mesoporous silica nanocarries for heart failure repair after myocardial infarction

Myocardial infarction (MI) may cause irreversible damage or destroy to part of the heart muscle, affecting the heart’s ability and power to pump blood as efficiently as before, often resulting in heart failure (HF). Cardiomyocyte death and scar formation after MI may then trigger chronic neurohormonal activation and ventricular remodeling. We developed a biocompatible and mono-dispersed mesoporous silica nanoparticles (MSN) divergent porous channel for dapagliflozin (DAPA) loading. After surface modification of the cardiac-targeting peptides, the novel drug delivery system was successfully homed, and precisely released drugs for the hypoxic and weak acid damaged cardiomyocytes. Our biocompatible MSN- based nanocarriers for dapagliflozin delivery system could effective cardiac repair and regeneration in vivo, opening new opportunities for healing patients with ischemic heart disease in clinical.

Detachable Microneedle Patches Deliver Mesenchymal Stromal Cell Factor-Loaded Nanoparticles for Cardiac Repair

Intramyocardial injection is a direct and efficient approach to deliver therapeutics to the heart. However, the injected volume must be very limited, and there is injury to the injection site and leakage issues during heart beating. Herein, we developed a detachable therapeutic microneedle (MN) patch, which is comprised of mesenchymal stromal cell-secreted factors (MSCF)-loaded poly(lactic-co-glycolic acid) nanoparticles (NP) in MN tips made of elastin-like polypeptide gel, with a resolvable non-cross-linked hyaluronic acid (HA) gel as the MN base. The tips can be firmly inserted into the infarcted myocardium after base removal, and no suture is needed. In isolated neonatal rat cardiac cells, we found that the cellular uptake of MSCF-NP in the cardiomyocytes was higher than in cardiac fibroblasts. MSCF-NP promoted the proliferation of injured cardiomyocytes. In a rat model of myocardial infarction, MN-MSCF-NP treatment reduced cardiomyocyte apoptosis, restored myocardium volume, and reduced fibrosis during the cardiac remodeling process. Our work demonstrated the therapeutic potential of MN to deliver MSCF directly into the myocardium and provides a promising treatment approach for cardiac diseases.

Engineered stem cell exosomes for oral and maxillofacial wound healing

Wound healing of the oral and maxillofacial area affects the quality of life and mental health of the patient; therefore, effective therapies are required to promote wound healing. However, traditional treatment methods have limited efficacy. Exosomes secreted by stem cells used for oral and maxillofacial wound healing have shown outstanding results. Stem cell-derived exosomes possess the regenerative and repair ability of stem cells. Moreover, they are nontumorigenic and have good biosafety. However, the application of natural stem cell exosomes is limited owing to their low yield, impurity, lack of targeting, and low drug delivery rate. Many modification methods have been developed to engineered stem cell exosomes with beneficial properties, such as modifying parent cells and directly processing stem cell exosomes. These methods include coincubation, genetic engineering, electroporation, ultrasound, and artificial synthesis of engineered stem cell exosomes. These engineered stem cell exosomes can cargo nucleic acids, proteins, and small molecules. This gives them anti-inflammatory and cell proliferation regulatory abilities and enables the targeted promotion of efficient soft tissue repair after trauma. Engineered stem cell exosomes can decrease inflammation, promote fibroblast proliferation, and angiogenesis, and decrease scar formation to promote oral and maxillofacial wound healing, including diabetic and burn wounds. Thus, engineered stem cell exosomes are an effective treatment that has the potential for oral and maxillofacial wound healing.

Exosomes as Potential Functional Nanomaterials for Tissue Engineering

Exosomes are cell-derived extracellular vesicles of 40-160 nm diameter, which carry numerous biomolecules and transmit information between cells. They are used as functional nanomaterials with great potential in biomedical areas, such as active agents and delivery systems for advanced drug delivery and disease therapy. In recent years, potential applications of exosomes in tissue engineering have attracted significant attention, and some critical progress has been made. This review gives a complete picture of exosomes and their applications in the regeneration of various tissues, such as the central nervous systems, kidney, bone, cartilage, heart, and endodontium. Approaches employed for modifying exosomes to equip them with excellent targeting capacity are summarized. Furthermore, current concerns and future outlook of exosomes in tissue engineering are discussed.

Heart-targeting exosomes from human cardiosphere-derived cells improve the therapeutic effect on cardiac hypertrophy

Exosomes of human cardiosphere-derived cells (CDCs) are very promising for treating cardiovascular disorders. However, the current challenge is inconvenient delivery methods of exosomes for clinical application. The present study aims to explore the potential to enhance the therapeutic effect of exosome (EXO) from human CDCs to myocardial hypertrophy. A heart homing peptide (HHP) was displayed on the surface of exosomes derived from CDCs that were forced to express the HHP fused on the N-terminus of the lysosomal-associated membrane protein 2b (LAMP2b). The cardiomyocyte-targeting capability of exosomes were analyzed and their therapeutic effects were evaluated in a mouse model of myocardial hypertrophy induced by transverse aorta constriction (TAC). The molecular mechanisms of the therapeutic effects were dissected in angiotensin II-induced neonatal rat cardiomyocyte (NRCMs) hypertrophy model using a combination of biochemistry, immunohistochemistry and molecular biology techniques. We found that HHP-exosomes (HHP-EXO) accumulated more in mouse hearts after intravenous delivery and in cultured NRCMs than control exosomes (CON-EXO). Cardiac function of TAC mice was significantly improved with intravenous HHP-EXO administration. Left ventricular hypertrophy was reduced more by HHP-EXO than CON-EXO via inhibition of β-MHC, BNP, GP130, p-STAT3, p-ERK1/2, and p-AKT. Similar results were obtained in angiotensin II-induced hypertrophy of NRCMs, in which the beneficial effects of HHP-EXO were abolished by miRNA-148a inhibition. Our results indicate that HHP-EXO preferentially target the heart and improve the therapeutic effect of CDCs-exosomes on cardiac hypertrophy. The beneficial therapeutic effect is most likely attributed to miRNA-148a-mediated suppression of GP130, which in turn inhibits STAT3/ERK1/2/AKT signaling pathway, leading to improved cardiac function and remodeling.

Exosomes and Exosomal Cargos: A Promising World for Ventricular Remodeling Following Myocardial Infarction

Exosomes are a pluripotent group of extracellular nanovesicles secreted by all cells that mediate intercellular communications. The effective information within exosomes is primarily reflected in exosomal cargos, including proteins, lipids, DNAs, and non-coding RNAs (ncRNAs), the most intensively studied molecules. Cardiac resident cells (cardiomyocytes, fibroblasts, and endothelial cells) and foreign cells (infiltrated immune cells, cardiac progenitor cells, cardiosphere-derived cells, and mesenchymal stem cells) are involved in the progress of ventricular remodeling (VR) following myocardial infarction (MI) via transferring exosomes into target cells. Here, we summarize the pathological mechanisms of VR following MI, including cardiac myocyte hypertrophy, cardiac fibrosis, inflammation, pyroptosis, apoptosis, autophagy, angiogenesis, and metabolic disorders, and the roles of exosomal cargos in these processes, with a focus on proteins and ncRNAs. Continued research in this field reveals a novel diagnostic and therapeutic strategy for VR.

Bioengineering Extracellular Vesicles for the Treatment of Cardiovascular Diseases

Cardiovascular diseases (CVD) remain one of the leading causes of mortality worldwide. Despite recent advances in diagnosis and interventions, there is still a crucial need for new multifaceted therapeutics that can address the complicated pathophysiological mechanisms driving CVD. Extracellular vesicles (EVs) are nanovesicles that are secreted by all types of cells to transport molecular cargo and regulate intracellular communication. EVs represent a growing field of nanotheranostics that can be leveraged as diagnostic biomarkers for the early detection of CVD and as targeted drug delivery vesicles to promote cardiovascular repair and recovery. Though a promising tool for CVD therapy, the clinical application of EVs is limited by the inherent challenges in EV isolation, standardization, and delivery. Hence, this review will present the therapeutic potential of EVs and introduce bioengineering strategies that augment their natural functions in CVD.

Multiplexed strategies toward clinical translation of extracellular vesicles

Extracellular vesicles (EVs), of which exosomes are a representative subgroup, are naturally secreted nanoparticles with a variety of payloads. With the intrinsic merits of stability, biocompatibility, low immunogenicity, and large capacity, EVs are widely regarded as effective carriers of drug delivery. However, disadvantages, such as low yield, complicated isolation procedures, and low loading efficiency, hinder its clinical translation. In this review, we systematically summarize the advances in EV (especially exosomes) engineering for clinical application, focusing on strategies toward high yield, facile isolation, efficient cargo loading, improved delivery, and optimized manufacturing, which might unleash the infinite power of EVs in clinical translation.

Recent advances of natural and bioengineered extracellular vesicles and their application in vascular regeneration

The progression of cardiovascular diseases such as atherosclerosis and myocardial infarction leads to serious vascular injury, highlighting the urgent need for targeted regenerative therapy. Extracellular vesicles (EVs) composed of a lipid bilayer containing nuclear and cytosolic materials are relevant to the progression of cardiovascular diseases. Moreover, EVs can deliver bioactive cargo in pathological cardiovascular and regulate the biological function of recipient cells, such as inflammation, proliferation, angiogenesis and polarization. However, because the targeting and bioactivity of natural EVs are subject to several limitations, bioengineered EVs have achieved wide advancements in biomedicine. Bioengineered EVs involve three main ways to acquire including (i) modification of the EVs after isolation; (ii) modification of producer cells before EVs’ isolation; (iii) synthesize EVs using natural or modified cell membranes, and encapsulating drugs or bioactive molecules into EVs. In this review, we first summarize the cardiovascular injury-related disease and describe the role of different cells and EVs in vascular regeneration. We also discuss the application of bioengineered EVs from different producer cells to cardiovascular diseases. Finally, we summarize the surface modification on EVs which can specifically target abnormal cells in injured vascular.

Extracellular Vesicles: A New Frontier for Cardiac Repair

The ability of extracellular vesicles (EVs) to regulate a broad range of cellular processes has recently been used to treat diseases. Growing evidence indicates that EVs play a cardioprotective role in heart disease by activating beneficial signaling pathways. Multiple functional components of EVs and intracellular molecular mechanisms are involved in the process. To overcome the shortcomings of native EVs such as their heterogeneity and limited tropism, a series of engineering approaches has been developed to improve the therapeutic efficiency of EVs. In this review, we present an overview of the research and future directions for EVs-based cardiac therapies with an emphasis on EVs-mediated delivery of therapeutic agents. The advantages and limitations of various modification strategies are discussed, and possible opportunities for improvement are proposed. An in-depth understanding of the endogenous properties of EVs and EVs engineering strategies could lead to a promising cell-free therapy for cardiac repair.

Functional Extracellular Vesicles for Regenerative Medicine

The unique biological characteristics and promising clinical potential of extracellular vesicles (EVs) have galvanized EV applications for regenerative medicine. Recognized as important mediators of intercellular communication, naturally secreted EVs have the potential, as innate biotherapeutics, to promote tissue regeneration. Although EVs have emerged as novel therapeutic agents, challenges related to the clinical transition have led to further functionalization. In recent years, various engineering approaches such as preconditioning, drug loading, and surface modification have been developed to potentiate the therapeutic outcomes of EVs. Also, limitations of natural EVs have been addressed by the development of artificial EVs that offer advantages in terms of production yield and isolation methodologies. In this review, an updated overview of current techniques is provided for the functionalization of natural EVs and recent advances in artificial EVs, particularly in the scope of regenerative medicine.

Revascularization of chronic total occlusion coronary artery and cardiac regeneration

Coronary chronic total occlusion (CTO) contributes to the progression of heart failure in patients with ischemic cardiomyopathy. Randomized controlled trials demonstrated that percutaneous coronary intervention (PCI) for CTO significantly improves angina symptoms and quality of life but fails to reduce clinical events compared with optimal medical therapy. Even so, intervening physicians strongly support CTO-PCI. Cardiac regeneration therapy after CTO-PCI should be a promising approach to improving the prognosis of ischemic cardiomyopathy. However, the relationship between CTO revascularization and cardiac regeneration has rarely been studied, and experimental studies on cardiac regeneration usually employ rodent models with permanent ligation of the coronary artery rather than reopening of the occlusive artery. Limited early-stage clinical trials demonstrated that cell therapy for cardiac regeneration in ischemic cardiomyopathy reduces scar size, reverses cardiac remodeling, and promotes angiogenesis. This review focuses on the status quo of CTO-PCI in ischemic cardiomyopathy and the clinical prospect of cardiac regeneration in this setting.

Interleukin-4 Receptor Targeting Peptide Decorated Extracellular Vesicles as a Platform for In Vivo Drug Delivery to Thyroid Cancer

Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) have been demonstrated to deliver therapeutic drugs in preclinical studies. However, their use is limited, as they lack the ability to specifically deliver drugs to tumor tissues in vivo. In the present study, we propose the use of a targeting peptide, IL-4R-binding peptide (IL4RPep-1), to specifically deliver intravenously (i.v.) infused EVs to thyroid tumors. In vivo, a xenograft tumor model was treated with either the control peptide (NSSSVDK) or IL4RPep-1-Flamma; mice were fluorescently imaged (FLI) using an in vivo imaging system at 0–3 h post-treatment. EVs (labeled with DiD dye) were conjugated with IL4RPep-1 through a DOPE-NHS linker and administered to mice intravenously. FLI was performed 0–24 h post-injection, and the animals were sacrificed for further experiments. The morphology and size of EVs, the presence of EV markers such as CD63 and ALIX, and the absence of the markers GM130 and Cyto-C were confirmed. In vivo, FLI indicated an accumulation of i.v. injected IL4RPep-1-Flamma at the tumor site 90 min post-injection. No accumulation of NSSSVDK-Flamma was detected. In vivo, IL4RPep-1-EVs targeted the Cal-62 tumor 2 h post-injection. NSSSVDK-EVs were not even detected in the tumor 24 h post-injection. The quantification of FLI showed a significant accumulation of MSC-EVs in the tumor 2 h, 3 h, and 24 h post-injection. Furthermore, ex vivo imaging and an IF analysis confirmed the in vivo findings. Our results demonstrate the use of the IL4RPep-1 peptide as a targeting moiety of EVs for IL-4R-expressing anaplastic thyroid tumors.

Bioengineering exosomes for treatment of organ ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury is a leading cause of death worldwide. It arises from blood reflowing after tissue hypoxia induced by ischemia that causes severe damages due to the accumulation of reactive oxygen species and the activation of inflammatory responses. Exosomes are the smallest members of the extracellular vesicles' family, which originate from nearly all eukaryotic cells. Exosomes have a great potential in the treatment of I/R injury either in native or modified forms. Native exosomes are secreted by different cell types, such as stem cells, and contain components such as specific miRNA molecules with tissue protective properties. On the other hand, exosome bioengineering has recently received increased attention in context of current advances in the purification, manipulation, biological characterization, and pharmacological applications. There are various pre-isolation and post-isolation manipulation approaches that can be utilized to increase the circulation half-life of exosomes or the availability of their bioactive cargos in the target site. In this review, the various therapeutic actions of native exosomes in different I/R injury will be discussed first. Exosome bioengineering approaches will then be explained, including pre- and post-isolation manipulation methods, applicability for delivery of bioactive agents to injured tissue, clinical translation issues, and future perspectives.

Nano-Messengers of the Heart: Promising Theranostic Candidates for Cardiovascular Maladies

Till date, cardiovascular diseases remain a leading cause of morbidity and mortality across the globe. Several commonly used treatment methods are unable to offer safety from future complications and longevity to the patients. Therefore, better and more effective treatment measures are needed. A potential cutting-edge technology comprises stem cell-derived exosomes. These nanobodies secreted by cells are intended to transfer molecular cargo to other cells for the establishment of intercellular communication and homeostasis. They carry DNA, RNA, lipids, and proteins; many of these molecules are of diagnostic and therapeutic potential. Several stem cell exosomal derivatives have been found to mimic the cardioprotective attributes of their parent stem cells, thus holding the potential to act analogous to stem cell therapies. Their translational value remains high as they have minimal immunogenicity, toxicity, and teratogenicity. The current review highlights the potential of various stem cell exosomes in cardiac repair, emphasizing the recent advancements made in the development of cell-free therapeutics, particularly as biomarkers and as carriers of therapeutic molecules. With the use of genetic engineering and biomimetics, the field of exosome research for heart treatment is expected to solve various theranostic requirements in the field paving its way to the clinics.

Gene therapy to terminate tachyarrhythmias

INTRODUCTION

To date, the treatment option for tachyarrhythmia is classified into drug therapy, catheter ablation, and implantable device therapy. However, the efficacy of the antiarrhythmic drugs is limited. Although the indication of catheter ablation is expanding, several fatal tachyarrhythmias are still refractory to ablation. Implantable cardioverter-defibrillator increases survival, but it is not a curable treatment. Therefore, a novel therapy for tachyarrhythmias refractory to present treatments is desired. Gene therapy is being developed as a promising candidate for this purpose, and basic research and translational research have been accumulated in recent years.

AREAS COVERED

This paper reviews the current state of gene therapy for arrhythmias, including susceptible arrhythmias, the route of administration to the heart, and the type of vector to use. We also discuss the latest progress in the technology of gene delivery and genome editing.

EXPERT OPINION

Gene therapy is one of the most promising technologies for arrhythmia treatment. However, additional technological innovation to achieve safe, localized, homogeneous, and long-lasting gene transfer is required for its clinical application.

Applications of Extracellular Vesicles in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a localized expansion of the abdominal aorta which can lead to lethal complication as the rupture of aortic wall. Currently there is still neither competent method to predict the impending rupture of aneurysm, nor effective treatment to arrest the progression of small and asymptomatic aneurysms. Accumulating evidence has confirmed the crucial role of extracellular vesicles (EVs) in the pathological course of AAA, acting as important mediators of intercellular communication. Given the advantages of intrinsic targeting properties, lower toxicity and fair stability, EVs show great potential to serve as biomarkers, therapeutic agents and drug delivery carriers. However, EV therapies still face several major challenges before they can be applied clinically, including off-target effect, low accumulation rate and rapid clearance by mononuclear phagocyte system. In this review, we first illustrate the roles of EV in the pathological process of AAA and evaluate its possible clinical applications. We also identify present challenges for EV applications, highlight different strategies of EV engineering and constructions of EV-like nanoparticles, including EV display technology and membrane hybrid technology. These leading-edge techniques have been recently employed in multiple cardiovascular diseases and their promising application in the field of AAA is discussed.

The in vivo fate and targeting engineering of crossover vesicle-based gene delivery system

Exosomes and biomimetic vesicles are widely used for gene delivery because of their excellent gene loading capacity and stability and their natural targeting delivery potential. These vesicles take advantages of both cell-based bioactive delivery system and synthetical lipid-derived nanovectors to form crossover characteristics. To further optimize the specific targeting properties of crossover vesicles, studies of their in vivo fate and various engineering approaches including nanobiotechnology are required. This review describes the preparation process of exosomes and biomimetic vesicles, and summarizes the mechanism of loading and delivery of nucleic acids or gene editing systems. We provide a comprehensive overview of the techniques employed for preparing the targeting crossover vesicles based on their cellular uptake and targeting mechanism. To delineate the future prospects of crossover vesicle gene delivery systems, various challenges and clinical applications of vesicles have also been discussed.

Engineered extracellular vesicles and their mimics in cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Current pharmacological interventions for the CVDs suffer from low bioavailability, low retention rate, poor targeting, drug resistance complicated side effects. Extracellular vesicles (EVs), which are lipid vesicles secreted by cells, play key roles in pathological processes of CVDs. Engineered EVs and EV mimics with superior properties can overcome limitations of traditional medicine, thus emerging as alternative therapeutic options for the CVDs. In this Review, we summarized basic concepts of EVs and EV mimics, highlighted engineering strategies, and lastly discussed applications of engineered EVs and EV mimics against the CVDs. We believe this Review can provide some new insights on engineering EVs and EV mimics and facilitate their application in precise control of CVDs.

Minimally invasive delivery of a hydrogel-based exosome patch to prevent heart failure

Coronary heart disease (CHD) has been the number one killer in the United States for decades and causes millions of deaths each year. Clinical treatment of heart ischemic injury relieves symptoms in the acute stage of CHD; however, patients with an infarcted heart muscle can develop heart failure (HF) due to chronic maladaptive remodeling. Regenerative therapy has been studied as a potential treatment option for myocardial infarction (MI) and HF. Cardiac patches have been designed and tested to increase therapeutic retention and integration in this field. However, the delivery usually requires invasive surgical techniques, including open-chest surgeries and heart or pericardium manipulation. Those procedures may cause chronic adhesions between the heart anterior wall and chest wall. This study created and tested an injectable ExoGel by embedding mesenchymal stem cell (MSC) -derived exosomes into hyaluronic acid (HA) hydrogel. ExoGel was injected into the pericardial cavity of rats with transverse aortic constriction (TAC) induced heart failure. ExoGel therapy reduced LV chamber size and preserved wall thickness. The feasibility and safety ExoGel injection was further confirmed in a pig model.

Nanocarrier-Based Targeted Therapies for Myocardial Infarction

Myocardial infarction is a major cause of morbidity and mortality worldwide. Due to poor inherent regeneration of the adult mammalian myocardium and challenges with effective drug delivery, there has been little progress in regenerative therapies. Nanocarriers, including liposomes, nanoparticles, and exosomes, offer many potential advantages for the therapy of myocardial infarction, including improved delivery, retention, and prolonged activity of therapeutics. However, there are many challenges that have prevented the widespread clinical use of these technologies. This review aims to summarize significant principles and developments in the field, with a focus on nanocarriers using ligand-based or cell mimicry-based targeting. Lastly, a discussion of limitations and potential future direction is provided.

Injection-Free Delivery of MSC-Derived Extracellular Vesicles for Myocardial Infarction Therapeutics

As emerging therapeutic factors, extracellular vesicles (EVs) offer significant potential for myocardial infarction (MI) treatment. Current delivery approaches for EVs involve either intra-myocardial or intravenous injection, where both have inherent limitations for downstream clinical applications such as secondary tissue injury and low delivery efficiency. Herein, an injection-free approach for delivering EVs onto the heart surface to treat MI is proposed. By spraying a mixture of EVs, gelatin methacryloyl (GelMA) precursors, and photoinitiators followed by visible light irradiation for 30 s, EVs are physically entrapped within the GelMA hydrogel network covering the surface of the heart, resulting in an enhanced retention rate. Moreover, EVs are gradually released from the hydrogel network through a combination of diffusion and/or enzymatic degradation of the hydrogel, and they are effectively taken up by the sprayed tissue area. More importantly, the released EVs further migrate deep into myocardium tissue, which exerts an improved therapeutic effect. In an MI-induced mice model, the group treated with EVs-laden GelMA hydrogels shows significant recovery in cardiac function after 4 weeks. The work demonstrates a new strategy for delivering EVs into cardiac tissues for MI treatment in a localized manner with high retention.

Modified Exosomes: a Good Transporter for miRNAs within Stem Cells to Treat Ischemic Heart Disease

Stem cell-based therapy for ischemic heart disease (IHD) has become a promising but controversial strategy during the past two decades. The fate and effects of stem cells engrafted into ischemia myocardium are still not fully understood. Stem cell-derived exosomes, a subcategory of extracellular vesicles with nano size, have been considered as an efficient and safe transporter for microRNAs (miRNAs) and a central mediator of the cardioprotective potentials of the parental cells. Hypoxia, pharmacological intervention, and gene manipulation could alter the exosomal miRNAs cargos from stem cells and promote therapeutic potential. Furthermore, several bioengineering methods were also successfully applied to modify miRNAs content and components of exosomal membrane proteins recently. In this review, we outline relevant results about exosomal miRNAs from stem cells and focus on the current strategies to promote their therapeutic efficiency in IHD.

A Dual-Reporter Platform for Screening Tumor-Targeted Extracellular Vesicles

Extracellular vesicle (EV)-mediated transfer of biomolecules plays an essential role in intercellular communication and may improve targeted drug delivery. In the past decade, various approaches to EV surface modification for targeting specific cells or tissues have been proposed, including genetic engineering of parental cells or postproduction EV engineering. However, due to technical limitations, targeting moieties of engineered EVs have not been thoroughly characterized. Here, we report the bioluminescence resonance energy transfer (BRET) EV reporter, PalmReNL-based dual-reporter platform for characterizing the cellular uptake of tumor-homing peptide (THP)-engineered EVs, targeting PDL1, uPAR, or EGFR proteins expressed in MDA-MB-231 breast cancer cells, simultaneously by bioluminescence measurement and fluorescence microscopy. Bioluminescence analysis of cellular EV uptake revealed the highest binding efficiency of uPAR-targeted EVs, whereas PDL1-targeted EVs showed slower cellular uptake. EVs engineered with two known EGFR-binding peptides via lipid nanoprobes did not increase cellular uptake, indicating that designs of EGFR-binding peptide conjugation to the EV surface are critical for functional EV engineering. Fluorescence analysis of cellular EV uptake allowed us to track individual PalmReNL-EVs bearing THPs in recipient cells. These results demonstrate that the PalmReNL-based EV assay platform can be a foundation for high-throughput screening of tumor-targeted EVs.

Extracellular Circular RNAs Act as Novel First Messengers Mediating Cell Cross-Talk in Ischemic Cardiac Injury and Myocardial Remodeling

Myocardial infarction (MI) causes most of the mortality worldwide. Coronary obstruction-caused myocardial ischemic injury leads to permanent loss of the myocardium. Subsequent compensatory myocardial remodeling and heart failure would result in arrhythmia and even sudden death. The molecular mechanisms of these pathological processes remain to be thoroughly revealed. Circular RNAs (circRNAs) are special types of non-coding RNAs which can durably regulate gene expression and modulate cell fate. They had been reported to mediate ischemic myocardial injury and myocardial remodeling. circRNAs can be loaded into extracellular vesicles and released into extracellular space. More recently, it was uncovered that the extracellular circRNAs can regulate intercellular communications, similar to "first messengers." The cross-talk mediated by extracellular circRNAs had been demonstrated to play important roles in pathological processes. Here, we would like to review the modulation of extracellular circRNAs in ischemic myocardial injury and myocardial remodeling. We believe the extracellular circRNAs can bring new strategies of MI treatment.

Extracellular Vesicles as a Cell-free Therapy for Cardiac Repair: a Systematic Review and Meta-analysis of Randomized Controlled Preclinical Trials in Animal Myocardial Infarction Models

Stem  cell therapy for cardiac regeneration has been gaining traction as a possible intervention for the reduction of the burden associated with MI and heart failure. However, stem cell therapies have several shortcomings, including poor engraftment, limited improvements in cardiac function, and possible teratogenicity. Recently, extracellular vesicles (EVs) from stem cell sources have been explored as a novel therapy to regenerate the injured myocardium in several animal MI trials. In this systematic review and meta-analysis, we investigate the use of stem cell-derived EVs for cardiac repair preclinical trials in animal MI models. Cochrane Library, Medline, Embase, PubMed, Scopus and Web of Science and grey literature (Canadian Agency for Drugs, Technologies in Health, and Google Scholar) were searched through August 20, 2020 and 37 articles were included in the final analysis. The overall effect size observed in EV-treated small animals after MI for ejection fraction (EF) was 10.85 [95 %CI: 8.79, 12.90] and for fractional shortening (FS) was 7.19 [95 %CI: 5.43, 8.96] compared to control-treated animals. The most abundant stem cell source used were mesenchymal stem cells which showed robust improvements in EF and FS (MD = 11.89 [95 % CI: 9.44, 14.34] and MD = 6.96 [95 % CI: 4.97, 8.96], respectively). Significant publication bias was detected for EF and FS outcomes. This study supports the use of EVs derived from stem cells as a novel therapy for cardiac repair after MI. Further investigation in larger animal studies may be necessary before clinical trials.PROSPERO registration number: CRD42019142218.

Potential application of biomimetic exosomes in cardiovascular disease: focused on ischemic heart disease

Cardiovascular disease, especially ischemic heart disease, is a major cause of mortality worldwide. Cardiac repair is one of the most promising strategies to address advanced cardiovascular diseases. Despite moderate improvement in heart function via stem cell therapy, there is no evidence of significant improvement in mortality and morbidity beyond standard therapy. The most salutary effect of stem cell therapy are attributed to the paracrine effects and the stem cell-derived exosomes are known as a major contributor. Hence, exosomes are emerging as a promising therapeutic agent and potent biomarkers of cardiovascular disease. Furthermore, they play a role as cellular cargo and facilitate intercellular communication. However, the clinical use of exosomes is hindered by the absence of a standard operating procedures for exosome isolation and characterization, problems related to yield, and heterogeneity. In addition, the successful clinical application of exosomes requires strategies to optimize cargo, improve targeted delivery, and reduce the elimination of exosomes. In this review, we discuss the basic concept of exosomes and stem cell-derived exosomes in cardiovascular disease, and introduce current efforts to overcome the limitations and maximize the benefit of exosomes including engineered biomimetic exosomes.

Current Understanding of piRNA in Cardiovascular Diseases

The relationship regarding non-coding genomes and cardiovascular disease (CVD) has been explored in the past decade. As one of the leading causes of death, there remains a lack of sensitive and specific genomic biomarkers in the diagnosis and prognosis of CVD. Piwi-interacting RNA (piRNA) is a group of small non-coding RNA (ncRNA) which associated with Piwi proteins. There is an emerging strong body of evidence in support of a role for ncRNAs, including piRNAs, in pathogenesis and prognosis of CVD. This article reviews the current evidence for piRNA-regulated mechanisms in CVD, which could lead to the development of new therapeutic strategies for prevention and treatment.

Extracellular vesicles in pharmacology: Novel approaches in diagnostics and therapy

Exosomes are nano-sized lipid vesicles that are produced by all eukaryotic cells, and they typically range in size from 30 to 150 nm. Exosomes were discovered almost 40 years ago; however, the last two decades have attracted considerable attention due to exosomes' inherent abilities to shuttle nucleic acids, lipids and proteins between cells, along with their natural affinity to exosome target cells. From a pharmaceutical perspective, exosomes are regarded as naturally produced nanoparticle drug delivery vehicles. The application of exosomes as a means of drug delivery offers critical advantages compared to other nanoparticulate drug delivery systems, such as liposomes and polymeric nanoparticles. These advantages are due to the exosomes' intrinsic features, such as low immunogenicity, biocompatibility, stability, and their ability to overcome biological barriers. Herein, we outline the structure and origin of exosomes, as well as their biological functions. We also touch upon recent advances in exosome labeling, imaging and drug loading. Finally, we discuss exosomes in targeted drug delivery and clinical trial development.

Therapeutic Applications of Extracellular Vesicles for Myocardial Repair

Cardiovascular disease is the leading cause of human death worldwide. Drug thrombolysis, percutaneous coronary intervention, coronary artery bypass grafting and other methods are used to restore blood perfusion for coronary artery stenosis and blockage. The treatments listed prolong lifespan, however, rate of mortality ultimately remains the same. This is due to the irreversible damage sustained by myocardium, in which millions of heart cells are lost during myocardial infarction. The lack of pragmatic methods of myocardial restoration remains the greatest challenge for effective treatment. Exosomes are small extracellular vesicles (EVs) actively secreted by all cell types that act as effective transmitters of biological signals which contribute to both reparative and pathological processes within the heart. Exosomes have become the focus of many researchers as a novel drug delivery system due to the advantages of low toxicity, little immunogenicity and good permeability. In this review, we discuss the progress and challenges of EVs in myocardial repair, and review the recent development of extracellular vesicle-loading systems based on their unique nanostructures and physiological functions, as well as the application of engineering modifications in the diagnosis and treatment of myocardial repair.

Mechanobiological Strategies to Enhance Stem Cell Functionality for Regenerative Medicine and Tissue Engineering

Stem cells have been extensively used in regenerative medicine and tissue engineering; however, they often lose their functionality because of the inflammatory microenvironment. This leads to their poor survival, retention, and engraftment at transplantation sites. Considering the rapid loss of transplanted cells due to poor cell-cell and cell-extracellular matrix (ECM) interactions during transplantation, it has been reasoned that stem cells mainly mediate reparative responses via paracrine mechanisms, including the secretion of extracellular vesicles (EVs). Ameliorating poor cell-cell and cell-ECM interactions may obviate the limitations associated with the poor retention and engraftment of transplanted cells and enable them to mediate tissue repair through the sustained and localized presentation of secreted bioactive cues. Biomaterial-mediated strategies may be leveraged to confer stem cells enhanced immunomodulatory properties, as well as better engraftment and retention at the target site. In these approaches, biomaterials have been exploited to spatiotemporally present bioactive cues to stem cell-laden platforms (e.g., aggregates, microtissues, and tissue-engineered constructs). An array of biomaterials, such as nanoparticles, hydrogels, and scaffolds, has been exploited to facilitate stem cells function at the target site. Additionally, biomaterials can be harnessed to suppress the inflammatory microenvironment to induce enhanced tissue repair. In this review, we summarize biomaterial-based platforms that impact stem cell function for better tissue repair that may have broader implications for the treatment of various diseases as well as tissue regeneration.

Exosomes and Exosomal Non-coding RNAs Are Novel Promises for the Mechanism-Based Diagnosis and Treatments of Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia worldwide and has a significant impact on human health and substantial costs. Currently, there is a lack of accurate biomarkers for the diagnosis and prognosis of AF. Moreover, the long-term efficacy of the catheter ablation in the AF is unsatisfactory. Therefore, it is necessary to explore new biomarkers and treatment strategies for the mechanism-based AF. Exosomes are nano-sized biovesicles released by nearly all types of cells. Since the AF would be linked to the changes of the atrial cells and their microenvironment, and the AF would strictly influence the exosomal non-coding RNAs (exo-ncRNAs) expression, which makes them as attractive diagnostic and prognostic biomarkers for the AF. Simultaneously, the exo-ncRNAs have been found to play an important role in the mechanisms of the AF and have potential therapeutic prospects. Although the role of the exo-ncRNAs in the AF is being actively investigated, the evidence is still limited. Furthermore, there is a lack of consensus regarding the most appropriate approach for exosome isolation and characterization. In this article, we reviewed the new methodologies available for exosomes biogenesis, isolation, and characterization, and then discussed the mechanism of the AF and various levels and types of exosomes relevant to the AF, with the special emphasis on the exo-ncRNAs in the diagnosis, prognosis, and treatment of the mechanism-based AF.

Dosing extracellular vesicles

Extracellular vesicles (EVs) are natural nanoparticles containing biologically active molecules. They are important mediators of intercellular communication and can be exploited therapeutically by various bioengineering approaches. To accurately determine the therapeutic potential of EVs in pre-clinical and clinical settings, dependable dosing strategies are of utmost importance. However, the field suffers from inconsistencies comprising all areas of EV production and characterisation. Therefore, a standardised and well-defined process in EV quantification, key to reliable therapeutic EV dosing, remains to be established. Here, we examined 64 pre-clinical studies for EV-based therapeutics with respect to their applied EV dosing strategies. We identified variations in effective dosing strategies irrespective of the applied EV purification method and cell source. Moreover, we found dose discrepancies depending on the disease model, where EV doses were selected without accounting for published EV pharmacokinetics or biodistribution patterns. We therefore propose to focus on qualitative aspects when dosing EV-based therapeutics, such as the potency of the therapeutic cargo entity. This will ensure batch-to-batch reliability and enhance reproducibility between applications. Furthermore, it will allow for the successful benchmarking of EV-based therapeutics compared to other nanoparticle drug delivery systems, such as viral vector-based or lipid-based nanoparticle approaches.

Extracellular vesicles in cardiovascular disease: Biological functions and therapeutic implications

Extracellular vesicles (EVs), including exosomes and microvesicles, are lipid bilayer particles naturally released from the cell. While exosomes are formed as intraluminal vesicles (ILVs) of the multivesicular endosomes (MVEs) and released to extracellular space upon MVE-plasma membrane fusion, microvesicles are generated through direct outward budding of the plasma membrane. Exosomes and microvesicles have same membrane orientation, different yet overlapping sizes; their cargo contents are selectively packed and dependent on the source cell type and functional state. Both exosomes and microvesicles can transfer bioactive RNAs, proteins, lipids, and metabolites from donor to recipient cells and influence the biological properties of the latter. Over the last decade, their potential roles as effective inter-tissue communicators in cardiovascular physiology and pathology have been increasingly appreciated. In addition, EVs are attractive sources of biomarkers for the diagnosis and prognosis of diseases, because they acquire their complex cargoes through cellular processes intimately linked to disease pathogenesis. Furthermore, EVs obtained from various stem/progenitor cell populations have been tested as cell-free therapy in various preclinical models of cardiovascular diseases and demonstrate unequivocally encouraging benefits. Here we summarize the findings from recent research on the biological functions of EVs in the ischemic heart disease and heart failure, and their potential as novel diagnostic biomarkers and therapeutic opportunities.

Mechanism of miR-30b-5p-Loaded PEG-PLGA Nanoparticles for Targeted Treatment of Heart Failure

Objective: Exploring the effectiveness of miR-30b-5p-loaded PEG-PLGA nanoparticles (NPs) for the treatment of heart failure and the underlying mechanism.

Methods: PEG-PLGA characteristics with different loading amounts were first examined to determine the loading, encapsulation, and release of miR-30b-5p from NPs. The effects of miR-30b-5p NPs on cardiac function and structure were assessed by immunofluorescence, echocardiography, HE/Masson staining, and TUNEL staining. The effects of NPs on the expression of factors related to cardiac hypertrophy and inflammation were examined by RT-PCR and western blotting, and the mechanism of miR-30b-5p treatment on heart failure was explored by dual luciferase reporter assay and RT-PCR.

Results: The size of PEG-PLGA NPs with different loading amounts ranged from 200 to 300 nm, and the zeta potential of PEG-PLGA NPs was negative. The mean entrapment efficiency of the NPs for miR-30b-5p was high (81.8 ± 2.1%), and the release rate reached 5 days with more than 90% release. Distribution experiments showed that NPs were mainly distributed in the heart and had a protective effect on myocardial injury and cardiac function. Compared with a rat model of cardiac failure and miR-30b-5p-non-loaede NP groups, the expression of cardiac hypertrophy markers (ANP, BNPβ-MHC) and inflammatory factors (IL-1β, IL-6) were significantly decreased. Dual luciferase reporter assay assays indicated that miR-30b-5p exerted its effects mainly by targeting TGFBR2.

Conclusion: PEG-PLGA NPs loaded with miR-30b-5p improved cardiac function, attenuated myocardial injury, and regulated the expression of factors associated with cardiac hypertrophy and inflammation by targeting TGFBR2.

Therapeutic perspectives of extracellular vesicles and extracellular microRNAs in atherosclerosis

Extracellular signaling molecules, such as growth factors, cytokines, and hormones, regulate cell behaviors and fate through endocrine, paracrine, and autocrine actions and play essential roles in maintaining tissue homeostasis. MicroRNAs, an important class of posttranscriptional modulators, could stably present in extracellular space and body fluids and participate in intercellular communication in health and diseases. Indeed, recent studies demonstrated that microRNAs could be secreted through vesicular and non-vesicular routes, transported in body fluids, and then transmitted to recipient cells to regulate target gene expression and signaling events. Over the past decade, a great deal of effort has been made to investigate the functional roles of extracellular vesicles and extracellular microRNAs in pathological conditions. Emerging evidence suggests that altered levels of extracellular vesicles and extracellular microRNAs in body fluids, as part of the cellular responses to atherogenic factors, are associated with the development of atherosclerosis. This review article provides a brief overview of extracellular vesicles and perspectives of their applications as therapeutic tools for cardiovascular pathologies. In addition, we highlight the role of extracellular microRNAs in atherogenesis and offer a summary of circulating microRNAs in liquid biopsies associated with atherosclerosis.

Biomolecules in cell-derived extracellular vesicle chariots as warriors to repair damaged tissues

In this review, we highlight the innovative applications of biomolecules from parent cell-derived extracellular vesicles (EVs) for tissue repair that have been developed in recent years. We evaluate the underlying mechanisms and therapeutic efficacy of each therapy. In previous literature reviews, it was most common to classify the use of EVs in tissue repair by disease type. This article reviews the role of three biomolecules in EVs in tissue repair. This review first summarizes the definitions and classifications of EVs. Then, the importance and significance of treating tissue damage with EVs are discussed. In particular, EV contents for tissue repair are three main types of biomolecules: proteins, RNAs and cell growth factors. The therapeutic and repair mechanisms of the biomolecules are discussed respectively. Finally, the development prospect and potential challenges of EV contents from highly differentiated cells as specific agents for tissue repair are summarized. When EVs are used to treat diseases such as tissue or organ damage, EVs play a role in delivery, and the real repair effect is effected by the various biomolecules carried by EVs. We believe that EV biomolecules have unparalleled advantages and clinical transformation potential for tissue repair and expect this review to inspire more intensive research work in this field.

Exosome-eluting stents for vascular healing after ischaemic injury

Drug-eluting stents implanted after ischaemic injury reduce the proliferation of endothelial cells and vascular smooth muscle cells and thus neointimal hyperplasia. However, the eluted drug also slows down the re-endothelialization process, delays arterial healing and can increase the risk of late restenosis. Here we show that stents releasing exosomes derived from mesenchymal stem cells in the presence of reactive oxygen species enhance vascular healing in rats with renal ischaemia-reperfusion injury, promoting endothelial cell tube formation and proliferation, and impairing the migration of smooth muscle cells. Compared with drug-eluting stents and bare-metal stents, the exosome-coated stents accelerated re-endothelialization and decreased in-stent restenosis 28 days after implantation. We also show that exosome-eluting stents implanted in the abdominal aorta of rats with unilateral hindlimb ischaemia regulated macrophage polarization, reduced local vascular and systemic inflammation, and promoted muscle tissue repair.

Development of Extracellular Vesicle Therapeutics: Challenges, Considerations, and Opportunities

Extracellular vesicles (EVs) hold great promise as therapeutic modalities due to their endogenous characteristics, however, further bioengineering refinement is required to address clinical and commercial limitations. Clinical applications of EV-based therapeutics are being trialed in immunomodulation, tissue regeneration and recovery, and as delivery vectors for combination therapies. Native/biological EVs possess diverse endogenous properties that offer stability and facilitate crossing of biological barriers for delivery of molecular cargo to cells, acting as a form of intercellular communication to regulate function and phenotype. Moreover, EVs are important components of paracrine signaling in stem/progenitor cell-based therapies, are employed as standalone therapies, and can be used as a drug delivery system. Despite remarkable utility of native/biological EVs, they can be improved using bio/engineering approaches to further therapeutic potential. EVs can be engineered to harbor specific pharmaceutical content, enhance their stability, and modify surface epitopes for improved tropism and targeting to cells and tissues in vivo. Limitations currently challenging the full realization of their therapeutic utility include scalability and standardization of generation, molecular characterization for design and regulation, therapeutic potency assessment, and targeted delivery. The fields' utilization of advanced technologies (imaging, quantitative analyses, multi-omics, labeling/live-cell reporters), and utility of biocompatible natural sources for producing EVs (plants, bacteria, milk) will play an important role in overcoming these limitations. Advancements in EV engineering methodologies and design will facilitate the development of EV-based therapeutics, revolutionizing the current pharmaceutical landscape.

A Bibliometric Analysis of Exosomes in Cardiovascular Diseases From 2001 to 2021

Background: Exosomes in cardiovascular diseases (CVDs) have become an active research field with substantial value and potential. Nevertheless, there are few bibliometric studies in this field. We aimed to visualize the research hotspots and trends of exosomes in CVDs using a bibliometric analysis to help understand the future development of basic and clinical research.

Methods: The articles and reviews regarding exosomes in the CVDs were culled from the Web of Science Core Collection, and knowledge maps were generated using CiteSpace and VOSviewer software.

Results: A total of 1,039 articles were included. The number of exosome articles in the CVDs increased yearly. These publications came from 60 countries/regions, led by the US and China. The primary research institutions were Shanghai Jiao Tong University and Nanjing Medical University. Circulation Research was the journal and co-cited journal with the most studies. We identified 473 authors among which Lucio Barile had the most significant number of articles and Thery C was co-cited most often. After analysis, the most common keywords are myocardium infarction, microRNA and mesenchymal stem cells. Ischemic heart disease, pathogenesis, regeneration, stem cells, targeted therapy, biomarkers, cardiac protection, and others are current and developing areas of study.

Conclusion: We identified the research hotspots and trends of exosomes in CVDs using bibliometric and visual methods. Research on exosomes is flourishing in the cardiovascular medicine. Regenerative medicine, exosome engineering, delivery vehicles, and biomarkers will likely become the focus of future research.

Percutaneous Intracoronary Delivery of Plasma Extracellular Vesicles Protects the Myocardium Against Ischemia-Reperfusion Injury in Canis

[Figure: see text].

Cardiac Fibrosis: Cellular Effectors, Molecular Pathways, and Exosomal Roles

Cardiac fibrosis, a common pathophysiologic process in most heart diseases, refers to an excess of extracellular matrix (ECM) deposition by cardiac fibroblasts (CFs), which can lead to cardiac dysfunction and heart failure subsequently. Not only CFs but also several other cell types including macrophages and endothelial cells participate in the process of cardiac fibrosis via different molecular pathways. Exosomes, ranging in 30-150 nm of size, have been confirmed to play an essential role in cellular communications by their bioactive contents, which are currently a hot area to explore pathobiology and therapeutic strategy in multiple pathophysiologic processes including cardiac fibrosis. Cardioprotective factors such as RNAs and proteins packaged in exosomes make them an excellent cell-free system to improve cardiac function without significant immune response. Emerging evidence indicates that targeting selective molecules in cell-derived exosomes could be appealing therapeutic treatments in cardiac fibrosis. In this review, we summarize the current understandings of cellular effectors, molecular pathways, and exosomal roles in cardiac fibrosis.

Therapeutic effects of bone marrow mesenchymal stem cells-derived exosomes on osteoarthritis

Mesenchymal stem cells (MSCs) have shown chondroprotective effects in clinical models of osteoarthritis (OA). However, effects of MSC‐derived exosomes on OA remain unclear. The study aimed to investigate the therapeutic potential of exosomes from human bone marrow MSCs (BM‐MSCs) in alleviating OA. The anterior cruciate ligament transection (ACLT) and destabilization of the medial meniscus (DMM) surgery were performed on the knee joints of a rat OA model, followed by intra‐articular injection of BM‐MSCs or their exosomes. In addition, BM‐MSC‐derived exosomes were administrated to primary human chondrocytes to observe the functional and molecular alterations. Both of BM‐MSCs and BM‐MSC‐derived exosomes alleviated cartilage destruction and subchondral bone remodelling in OA rat model. Administration of BM‐MSCs and exosomes could reduce joint damage and restore the trabecular bone volume fraction, trabecular number and connectivity density of OA rats. In addition, in vitro assays showed that BM‐MSCs‐exosomes could maintain the chondrocyte phenotype by increasing collagen type II synthesis and inhibiting IL‐1β–induced senescence and apoptosis. Furthermore, exosomal lncRNA MEG‐3 also reduced the senescence and apoptosis of chondrocytes induced by IL‐1β, indicating that lncRNA MEG‐3 might partially account the anti‐OA effects of BM‐MSC exosomes. The exosomes from BM‐MSCs exerted beneficial therapeutic effects on OA by reducing the senescence and apoptosis of chondrocytes, suggesting that MSC‐derived exosomes might provide a candidate therapy for OA treatment.

Engineered exosomes: desirable target-tracking characteristics for cerebrovascular and neurodegenerative disease therapies

As extracellular vesicles secreted by cells, exosomes are intercellular signalosomes for cell communication and pharmacological effectors. Because of their special properties, including low toxicity and immunogenicity, biodegradability, ability to encapsulate endogenous biologically active molecules and cross the blood-brain barrier (BBB), exosomes have great therapeutic potential in cerebrovascular and neurodegenerative diseases. However, the poor targeting ability of natural exosomes greatly reduces the therapeutic effect. Using engineering technology, exosomes can obtain active targeting ability to accumulate in specific cell types and tissues by attaching targeting units to the membrane surface or loading them into cavities. In this review, we outline the improved targeting functions of bioengineered exosomes, tracing and imaging techniques, administration methods, internalization in the BBB, and therapeutic effects of exosomes in cerebrovascular and neurodegenerative diseases and further evaluate the clinical opportunities and challenges in this research field.

Platelet membrane and stem cell exosome hybrid enhances cellular uptake and targeting to heart injury

Exosomes from mesenchymal stem cells have been largely studied as therapeutics to treat myocardial infarctions. However, exosomes injected for therapeutic purposes face a number of challenges, including competition from exosomes already in circulation, and the internalization/clearance by the mononuclear phagocyte system. In this study, we hybrid exosomes with platelet membranes to enhance their ability to target the injured heart and avoid being captured by macrophages. Furthermore, we found that encapsulation by the platelet membranes induces macropinocytosis, enhancing the cellular uptake of exosomes by endothelial cells and cardiomyocytes strikingly. In vivo studies showed that the cardiac targeting ability of hybrid exosomes in a mice model with myocardial infarction injury. Last, we tested cardiac functions and performed immunohistochemistry to confirm a better therapeutic effect of platelet membrane modified exosomes compared to non-modified exosomes. Our studies provide proof-of-concept data and a universal approach to enhance the binding and accumulation of exosomes in injured tissues.