Circulating exosomes derived from transplanted progenitor cells aid the functional recovery of ischemic myocardium

Programmable production of bioactive extracellular vesicles in vivo to treat myocardial infarction

Current myocardial infarction (MI) treatment strategies remain challenged in suboptimal pharmacokinetics and potential adverse effects. Here we present a bioelectronic interface capable of producing on-demand abundant bioactive extracellular vesicles (EVs) near the MI area for in-situ localized treatment. The technology, termed electroactive patch for wirelessly and controllable EV generation (ePOWER), leverages wireless bioelectronic patch to stimulate embedded electrosensitive macrophages, actively modulating the biosynthesis of EVs and enabling EV production with high programmability to be delivered directly to the MI area. ~2400% more bioactive EVs were produced per cell under our ePOWER system. When surgically implanted, we demonstrate the therapeutic potential of in-situ EV production system to alleviate MI symptoms and improve cardiac function. This programmable ePOWER technology enables in-situ production of therapeutically rich EVs, thus reducing the need for exogenous cell expansion platforms and dedicated delivery, holding promise as a therapeutic all-in-one platform to treat various diseases.

Small extracellular vesicles associated miRNA in myocardial fibrosis

Myocardial fibrosis involves the loss of cardiomyocytes, myocardial fibroblast proliferation, and a reduction in angiogenesis, ultimately leading to heart failure, Given its significant implications, it is crucial to explore novel therapies for myocardial fibrosis. Recently one emerging avenue has been the use of small extracellular vesicles (sEV)-carried miRNA. In this review, we summarize the regulatory role of sEV-carried miRNA in myocardial fibrosis. We explored not only the potential diagnostic value of circulating miRNA as biomarkers for heart disease but also the therapeutic implications of sEV-carried miRNA derived from various cellular sources and applications of modified sEV. This exploration is paramount for researchers striving to develop innovative, cell-free therapies as potential drug candidates for the management of myocardial fibrosis.

Emerging role of sphingolipids and extracellular vesicles in development and therapeutics of cardiovascular diseases

Sphingolipids are eighteen carbon alcohol lipids synthesized from non-sphingolipid precursors in the endoplasmic reticulum (ER). The sphingolipids serve as precursors for a vast range of moieties found in our cells that play a critical role in various cellular processes, including cell division, senescence, migration, differentiation, apoptosis, pyroptosis, autophagy, nutrition intake, metabolism, and protein synthesis. In CVDs, different subclasses of sphingolipids and other derived molecules such as sphingomyelin (SM), ceramides (CERs), and sphingosine-1-phosphate (S1P) are directly related to diabetic cardiomyopathy, dilated cardiomyopathy, myocarditis, ischemic heart disease (IHD), hypertension, and atherogenesis. Several genome-wide association studies showed an association between genetic variations in sphingolipid pathway genes and the risk of CVDs. The sphingolipid pathway plays an important role in the biogenesis and secretion of exosomes. Small extracellular vesicles (sEVs)/ exosomes have recently been found as possible indicators for the onset of CVDs, linking various cellular signaling pathways that contribute to the disease progression. Important features of EVs like biocompatibility, and crossing of biological barriers can improve the pharmacokinetics of drugs and will be exploited to develop next-generation drug delivery systems. In this review, we have comprehensively discussed the role of sphingolipids, and sphingolipid metabolites in the development of CVDs. In addition, concise deliberations were laid to discuss the role of sEVs/exosomes in regulating the pathophysiological processes of CVDs and the exosomes as therapeutic targets.

Comparison of the efficiency of ultrafiltration, precipitation, and ultracentrifugation methods for exosome isolation

Extracellular vesicles (EVs) are enclosed by a lipid-bilayer membrane and secreted by all types of cells. They are classified into three groups: apoptotic bodies, microvesicles, and exosomes. Exosomes play a number of important roles in the intercellular communication and crosstalk between tissues in the body. In this study, we use three common methods based on different principles for exosome isolation, namely ultrafiltration, precipitation, and ultracentrifugation. We use field emission scanning electron microscopy (FESEM) and dynamic light scattering (DLS) analyses for characterization of exosomes. The functionality and effect of isolated exosomes on the viability of hypoxic cells was investigated by alamarBlue and Flow-cytometry. The results of the FESEM study show that the ultrafiltration method isolates vesicles with higher variability of shapes and sizes when compared to the precipitation and ultracentrifugation methods. DLS results show that mean size of exosomes isolated by ultrafiltration, precipitation, and ultracentrifugation methods are 122, 89, and 60 nm respectively. AlamarBlue analysis show that isolated exosomes increase the viability of damaged cells by 11%, 15%, and 22%, respectively. Flow-cytometry analysis of damaged cells also show that these vesicles increase the content of live cells by 9%, 15%, and 20%, respectively. This study shows that exosomes isolated by the ultracentrifugation method are characterized by smaller size and narrow size distribution. Furthermore, more homogenous particles isolated by this method show increased efficiency of the protection of hypoxic cells in comparison with the exosomes isolated by the two other methods.

Adult cardiomyocytes-derived EVs for the treatment of cardiac fibrosis

Cardiac fibrosis is a common pathological feature of cardiovascular diseases that arises from the hyperactivation of fibroblasts and excessive extracellular matrix (ECM) deposition, leading to impaired cardiac function and potentially heart failure or arrhythmia. Extracellular vesicles (EVs) released by cardiomyocytes (CMs) regulate various physiological functions essential for myocardial homeostasis, which are disrupted in cardiac disease. Therefore, healthy CM-derived EVs represent a promising cell-free therapy for the treatment of cardiac fibrosis. To this end, we optimized the culture conditions of human adult CMs to obtain a large yield of EVs without compromising cellular integrity by using a defined combination of small molecules. EVs were isolated by ultracentrifugation, and their characteristics were analysed. Finally, their effect on fibrosis was tested. Treatment of TGFβ-activated human cardiac fibroblasts with EVs derived from CMs using our culture system resulted in a decrease in fibroblast activation markers and ECM accumulation. The rescued phenotype was associated with specific EV cargo, including multiple myocyte-specific and antifibrotic microRNAs, although their effect individually was not as effective as the EV treatment. Notably, pathway analysis showed that EV treatment reverted the transcription of activated fibroblasts and decreased several signalling pathways, including MAPK, mTOR, JAK/STAT, TGFβ, and PI3K/Akt, all of which are involved in fibrosis development. Intracardiac injection of CM-derived EVs in an animal model of cardiac fibrosis reduced fibrotic area and increased angiogenesis, which correlated with improved cardiac function. These findings suggest that EVs derived from human adult CMs may offer a targeted and effective treatment for cardiac fibrosis, owing to their antifibrotic properties and the specificity of cargo.

Endothelial progenitor cell-derived extracellular vesicles: the world of potential prospects for the treatment of cardiovascular diseases

Cardiovascular diseases (CVDs) have emerged as a predominant threat to human health, surpassing the incidence and mortality rates of neoplastic diseases. Extracellular vesicles (EVs) serve as vital mediators in intercellular communication and material exchange. Endothelial progenitor cells (EPCs), recognized as precursors of vascular endothelial cells (ECs), have garnered considerable attention in recent years due to the potential therapeutic value of their derived extracellular vesicles (EPC-EVs) in the context of CVDs. This comprehensive review systematically explores the origins, characteristics, and functions of EPCs, alongside the classification, properties, biogenesis, and extraction techniques of EVs, with particular emphasis on their protective roles in CVDs. Additionally, we delve into the essential bioactive components of EPC-EVs, including microRNAs, long non-coding RNAs, and proteins, analyzing their beneficial effects in promoting angiogenesis, anti-inflammatory and anti-oxidant activities, anti-fibrosis, anti-apoptosis, and myocardial regeneration. Furthermore, this review comprehensively investigates the therapeutic potential of EPC-EVs across various CVDs, encompassing acute myocardial infarction, myocardial ischemia-reperfusion injury, atherosclerosis, non-ischemic cardiomyopathies, and diabetic cardiovascular disease. Lastly, we summarize the potential challenges associated with the clinical application of EPC-EVs and outline future directions, aiming to offer a valuable resource for both theoretical insights and practical applications of EPC-EVs in managing CVDs.

Regulation of cardiac fibroblasts reprogramming into cardiomyocyte-like cells with a cocktail of small molecule compounds

Myocardial infarction results in extensive cardiomyocyte apoptosis, leading to the formation of noncontractile scar tissue. Given the limited regenerative capacity of adult mammalian cardiomyocytes, direct reprogramming of cardiac fibroblasts (CFs) into cardiomyocytes represents a promising therapeutic strategy for myocardial repair, and small molecule drugs might offer a more attractive alternative to gene editing approaches in terms of safety and clinical feasibility. This study aimed to reprogram rat CFs into cardiomyocytes using a small molecular chemical mixture comprising CHIR99021, Valproic acid, Dorsomorphin, SB431542, and Forskolin. Immunofluorescence analysis revealed a significant increase in the expression of cardiomyocyte-specific markers, including cardiac troponin T (cTnT), Connexin 43 (Cx43), α-actinin, and Tbx5. Changes in intracellular calcium ion levels and Ca2+ signal transfer between adjacent cells were monitored using a calcium ion fluorescence probe. mRNA sequencing analysis demonstrated the upregulation of genes associated with cardiac morphogenesis, myocardial differentiation, and muscle fiber contraction during CF differentiation induced by the small-molecule compounds. Conversely, the expression of fibroblast-related genes was downregulated. These findings suggest that chemical-induced cell fate conversion of rat CFs into cardiomyocyte-like cells is feasible, offering a potential therapeutic solution for myocardial injury.

The Effect of Parent Cell Type on Small Extracellular Vesicle-Derived Vehicle Functionality

Cell therapies involving c-kit+ progenitor cells (CPCs) and mesenchymal stem cells (MSCs) have been actively studied for cardiac repair. The benefits of such therapies have more recently been attributed to the release of small extracellular vesicles (sEVs) from the parent cells. These sEVs are 30-180 nm vesicles containing protein/nucleic acid cargo encapsulated within an amphiphilic bilayer membrane. Despite their pro-reparative effects, sEV composition and cargo loading is highly variable, making it challenging to develop robust therapies with sEVs. Synthetic alternatives have been developed to allow cargo modulation, including prior work from the laboratory, to design sEV-like vehicles (ELVs). ELVs are synthesized from the sEV membrane but allow controlled cargo loading. It is previously shown that loading pro-angiogenic miR-126 into CPC-derived ELVs significantly increases endothelial cell angiogenesis compared to CPC-sEVs alone. Here, they expand on this work to design MSC-derived ELVs  and study the role of the parent cell type on ELV composition and function. It is found that ELV origin does affect the ELV potency and that ELV membrane composition can affect outcomes. This study showcases the versatility of ELVs to be synthesized from different parent cells and highlights the importance of selecting ELV source cells based on the desired functional outcomes.

Statistical modeling of extracellular vesicle cargo to predict clinical trial outcomes for hypoplastic left heart syndrome

Cardiac-derived c-kit+ progenitor cells (CPCs) are under investigation in the CHILD phase I clinical trial (NCT03406884) for the treatment of hypoplastic left heart syndrome (HLHS). The therapeutic efficacy of CPCs can be attributed to the release of extracellular vesicles (EVs). To understand sources of cell therapy variability we took a machine learning approach: combining bulk CPC-derived EV (CPC-EV) RNA sequencing and cardiac-relevant in vitro experiments to build a predictive model. We isolated CPCs from cardiac biopsies of patients with congenital heart disease (n = 29) and the lead-in patients with HLHS in the CHILD trial (n = 5). We sequenced CPC-EVs, and measured EV inflammatory, fibrotic, angiogeneic, and migratory responses. Overall, CPC-EV RNAs involved in pro-reparative outcomes had a significant fit to cardiac development and signaling pathways. Using a model trained on previously collected CPC-EVs, we predicted in vitro outcomes for the CHILD clinical samples. Finally, CPC-EV angiogenic performance correlated to clinical improvements in right ventricle performance.

The role of miR1 and miR133a in new-onset atrial fibrillation after acute myocardial infarction

BACKGROUND

The development of new-onset atrial fibrillation (NOAF) after acute myocardial infarction (AMI) is a clinical complication that requires a better understanding of the causative risk factors. This study aimed to explore the risk factors and the expression and function of miR-1 and miR-133a in new atrial fibrillation after AMI.

METHODS

We collected clinical data from 172 patients with AMI treated with emergency percutaneous coronary intervention (PCI) between October 2021 and October 2022. Independent predictors of NOAF were determined using binary logistic univariate and multivariate regression analyses. The predictive value of NOAF was assessed using the area under the receiver operating characteristic (ROC) curve for related risk factors. In total, 172 venous blood samples were collected preoperatively and on the first day postoperatively; the expression levels of miR-1 and miR-133a were determined using the polymerase chain reaction. The clinical significance of miR-1 and miR-133a expression levels was determined by Spearman correlation analysis.

RESULTS

The Glasgow prognostic score, left atrial diameter, and infarct area were significant independent risk factors for NOAF after AMI. We observed that the expression levels of miR-1 and miR-133a were significantly higher in the NOAF group than in the non-NOAF group. On postoperative day 1, strong associations were found between miR-133a expression levels and the neutrophil ratio and between miR-1 expression levels and an increased left atrial diameter.

CONCLUSIONS

Our findings indicate that the mechanism of NOAF after AMI may include an inflammatory response associated with an increased miR-1-related mechanism. Conversely, miR-133a could play a protective role in this clinical condition.

Extracellular vesicles as next generation immunotherapeutics

Extracellular vesicles (EVs) function as a mode of intercellular communication and molecular transfer to elicit diverse biological/functional response. Accumulating evidence has highlighted that EVs from immune, tumour, stromal cells and even bacteria and parasites mediate the communication of various immune cell types to dynamically regulate host immune response. EVs have an innate capacity to evade recognition, transport and transfer functional components to target cells, with subsequent removal by the immune system, where the immunological activities of EVs impact immunoregulation including modulation of antigen presentation and cross-dressing, immune activation, immune suppression, and immune surveillance, impacting the tumour immune microenvironment. In this review, we outline the recent progress of EVs in immunorecognition and therapeutic intervention in cancer, including vaccine and targeted drug delivery and summarise their utility towards clinical translation. We highlight the strategies where EVs (natural and engineered) are being employed as a therapeutic approach for immunogenicity, tumoricidal function, and vaccine development, termed immuno-EVs. With seminal studies providing significant progress in the sequential development of engineered EVs as therapeutic anti-tumour platforms, we now require direct assessment to tune and improve the efficacy of resulting immune responses - essential in their translation into the clinic. We believe such a review could strengthen our understanding of the progress in EV immunobiology and facilitate advances in engineering EVs for the development of novel EV-based immunotherapeutics as a platform for cancer treatment.

Regeneration of the heart: from molecular mechanisms to clinical therapeutics

Heart injury such as myocardial infarction leads to cardiomyocyte loss, fibrotic tissue deposition, and scar formation. These changes reduce cardiac contractility, resulting in heart failure, which causes a huge public health burden. Military personnel, compared with civilians, is exposed to more stress, a risk factor for heart diseases, making cardiovascular health management and treatment innovation an important topic for military medicine. So far, medical intervention can slow down cardiovascular disease progression, but not yet induce heart regeneration. In the past decades, studies have focused on mechanisms underlying the regenerative capability of the heart and applicable approaches to reverse heart injury. Insights have emerged from studies in animal models and early clinical trials. Clinical interventions show the potential to reduce scar formation and enhance cardiomyocyte proliferation that counteracts the pathogenesis of heart disease. In this review, we discuss the signaling events controlling the regeneration of heart tissue and summarize current therapeutic approaches to promote heart regeneration after injury.

Exosomes in Cardiovascular Disease: From Mechanism to Therapeutic Target

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally. In recent decades, clinical research has made significant advances, resulting in improved survival and recovery rates for patients with CVD. Despite this progress, there is substantial residual CVD risk and an unmet need for better treatment. The complex and multifaceted pathophysiological mechanisms underlying the development of CVD pose a challenge for researchers seeking effective therapeutic interventions. Consequently, exosomes have emerged as a new focus for CVD research because their role as intercellular communicators gives them the potential to act as noninvasive diagnostic biomarkers and therapeutic nanocarriers. In the heart and vasculature, cell types such as cardiomyocytes, endothelial cells, vascular smooth muscle, cardiac fibroblasts, inflammatory cells, and resident stem cells are involved in cardiac homeostasis via the release of exosomes. Exosomes encapsulate cell-type specific miRNAs, and this miRNA content fluctuates in response to the pathophysiological setting of the heart, indicating that the pathways affected by these differentially expressed miRNAs may be targets for new treatments. This review discusses a number of miRNAs and the evidence that supports their clinical relevance in CVD. The latest technologies in applying exosomal vesicles as cargo delivery vehicles for gene therapy, tissue regeneration, and cell repair are described.

Knockdown of deleterious miRNA in progenitor cell-derived small extracellular vesicles enhances tissue repair in myocardial infarction

Small extracellular vesicles (sEVs) play a critical role in cardiac cell therapy by delivering molecular cargo and mediating cellular signaling. Among sEV cargo molecule types, microRNA (miRNA) is particularly potent and highly heterogeneous. However, not all miRNAs in sEV are beneficial. Two previous studies using computational modeling identified miR-192-5p and miR-432-5p as potentially deleterious in cardiac function and repair. Here, we show that knocking down miR-192-5p and miR-432-5p in cardiac c-kit+ cell (CPC)-derived sEVs enhances the therapeutic capabilities of sEVs in vitro and in a rat in vivo model of cardiac ischemia reperfusion. miR-192-5p- and miR-432-5p-depleted CPC-sEVs enhance cardiac function by reducing fibrosis and necrotic inflammatory responses. miR-192-5p-depleted CPC-sEVs also enhance mesenchymal stromal cell-like cell mobilization. Knocking down deleterious miRNAs from sEV could be a promising therapeutic strategy for treatment of chronic myocardial infarction.

Exosomes for angiogenesis induction in ischemic disorders

Ischaemic disorders are leading causes of morbidity and mortality worldwide. While the current therapeutic approaches have improved life expectancy and quality of life, they are unable to "cure" ischemic diseases and instate regeneration of damaged tissues. Exosomes are a class of extracellular vesicles with an average size of 100-150 nm, secreted by many cell types and considered a potent factor of cells for paracrine effects. Since exosomes contain multiple bioactive components such as growth factors, molecular intermediates of different intracellular pathways, microRNAs and nucleic acids, they are considered as cell-free therapeutics. Besides, exosomes do not rise cell therapy concerns such as teratoma formation, alloreactivity and thrombotic events. In addition, exosomes are stored and utilized more convenient. Interestingly, exosomes could be an ideal complementary therapeutic tool for ischemic disorders. In this review, we discussed therapeutic functions of exosomes in ischemic disorders including angiogenesis induction through various mechanisms with specific attention to vascular endothelial growth factor pathway. Furthermore, different delivery routes of exosomes and different modification strategies including cell preconditioning, gene modification and bioconjugation, were highlighted. Finally, pre-clinical and clinical investigations in which exosomes were used were discussed.

Intramyocardial cell-based therapy with Lomecel-B during bidirectional cavopulmonary anastomosis for hypoplastic left heart syndrome: the ELPIS phase I trial

Aims

Hypoplastic left heart syndrome (HLHS) survival relies on surgical reconstruction of the right ventricle (RV) to provide systemic circulation. This substantially increases the RV load, wall stress, maladaptive remodelling, and dysfunction, which in turn increases the risk of death or transplantation.

Methods and results

We conducted a phase 1 open-label multicentre trial to assess the safety and feasibility of Lomecel-B as an adjunct to second-stage HLHS surgical palliation. Lomecel-B, an investigational cell therapy consisting of allogeneic medicinal signalling cells (MSCs), was delivered via intramyocardial injections. The primary endpoint was safety, and measures of RV function for potential efficacy were obtained. Ten patients were treated. None experienced major adverse cardiac events. All were alive and transplant-free at 1-year post-treatment, and experienced growth comparable to healthy historical data. Cardiac magnetic resonance imaging (CMR) suggested improved tricuspid regurgitant fraction (TR RF) via qualitative rater assessment, and via significant quantitative improvements from baseline at 6 and 12 months post-treatment (P < 0.05). Global longitudinal strain (GLS) and RV ejection fraction (EF) showed no declines. To understand potential mechanisms of action, circulating exosomes from intramyocardially transplanted MSCs were examined. Computational modelling identified 54 MSC-specific exosome ribonucleic acids (RNAs) corresponding to changes in TR RF, including miR-215-3p, miR-374b-3p, and RNAs related to cell metabolism and MAPK signalling.

Conclusion

Intramyocardially delivered Lomecel-B appears safe in HLHS patients and may favourably affect RV performance. Circulating exosomes of transplanted MSC-specific provide novel insight into bioactivity. Conduct of a controlled phase trial is warranted and is underway.Trial registration number NCT03525418.

Neonatal Plasma Exosomes Contribute to Endothelial Cell-Mediated Angiogenesis and Cardiac Repair after Acute Myocardial Infarction

Acute myocardial infarction (AMI) accompanied by cardiac remodeling still lacks effective treatment to date. Accumulated evidences suggest that exosomes from various sources play a cardioprotective and regenerative role in heart repair, but their effects and mechanisms remain intricate. Here, we found that intramyocardial delivery of plasma exosomes from neonatal mice (npEXO) could help to repair the adult heart in structure and function after AMI. In-depth proteome and single-cell transcriptome analyses suggested that npEXO ligands were majorly received by cardiac endothelial cells (ECs), and npEXO-mediated angiogenesis might serve as a pivotal reason to ameliorate the infarcted adult heart. We then innovatively constructed systematical communication networks among exosomal ligands and cardiac ECs and the final 48 ligand-receptor pairs contained 28 npEXO ligands (including the angiogenic factors, Clu and Hspg2), which mainly mediated the pro-angiogenic effect of npEXO by recognizing five cardiac EC receptors (Kdr, Scarb1, Cd36, etc.). Together, the proposed ligand-receptor network in our study might provide inspiration for rebuilding the vascular network and cardiac regeneration post-MI.

Hydroxychloroquine Enhances Cytotoxic Properties of Extracellular Vesicles and Extracellular Vesicle-Mimetic Nanovesicles Loaded with Chemotherapeutics

Because of their high biocompatibility, biological barrier negotiation, and functionalization properties, biological nanoparticles have been actively investigated for many medical applications. Biological nanoparticles, including natural extracellular vesicles (EVs) and synthetic extracellular vesicle-mimetic nanovesicles (EMNVs), represent novel drug delivery vehicles that can accommodate different payloads. In this study, we investigated the physical, biological, and delivery properties of EVs and EMNVs and analyzed their ability to deliver the chemotherapeutic drug doxorubicin. EMNVs and EVs exhibit similar properties, but EMNVs are more effectively internalized, while EVs show higher intracellular doxorubicin release activity. In addition, these nanotherapeutics were investigated in combination with the FDA-approved drug hydroxychloroquine (HCQ). We demonstrate that HCQ-induced lysosome destabilization and could significantly increase nanoparticle internalization, doxorubicin release, and cytotoxicity. Altogether, these data demonstrate that, from the delivery standpoint in vitro, the internalization of EMNVs and EVs and their payload release were slightly different and both nanotherapeutics had comparable cytotoxic performance. However, the synthesis of EMNVs was significantly faster and cost-effective. In addition, we highlight the benefits of combining biological nanoparticles with the lysosome-destabilizing agent HCQ that increased both the internalization and the cytotoxic properties of the particles.

Hypoxia-inducible factor 1-alpha enhances the secretome to rejuvenate adult cardiosphere-derived cells

OBJECTIVE

After cardiac injury, endogenous repair mechanisms are ineffective. However, cell-based therapies provide a promising clinical intervention based on their ability to restore and remodel injured myocardium due to their paracrine factors. Recent clinical trials have demonstrated that adult cardiosphere-derived cell therapy is safe for the treatment of ischemic heart failure, although with limited regenerative potential. The limited efficiency of cardiosphere-derived cells after myocardial infarction is due to the inferior quality of their secretome. This study sought to augment the therapeutic potential of cardiosphere-derived cells by modulating hypoxia-inducible factor-1α, a regulator of paracrine factors.

METHODS

Cardiosphere-derived cells were isolated and expanded from the right atrial appendage biopsies of patients undergoing cardiac surgery. To study the effect of hypoxia-inducible factor-1α on the secretome, cardiosphere-derived cells were transduced with hypoxia-inducible factor-1α-overexpressing lentivirus, and various cardioprotective factors within the secretome were quantified using enzyme-linked immunosorbent assays. Comparative analysis of the regenerative potential of cardiosphere-derived cells was performed in a rat myocardial infarction model.

RESULTS

Mechanistically, overexpression of hypoxia-inducible factor-1α in adult cardiosphere-derived cells led to the enrichment of the secretome with vascular endothelial growth factor A, angiopoietin 1, stromal cell-derived factor 1α, and basic fibroblast growth factor. Intramyocardial administration of cardiosphere-derived cells transduced with hypoxia-inducible factor-1α after myocardial infarction significantly improved left ventricular ejection fraction, fractional shortening, left ventricular end-systolic volume, and cardiac output. Functional improvement of the rat heart correlated with improved adaptive remodeling of the infarcted myocardium by enhanced angiogenesis and decreased myocardial fibrosis. We also showed that hypoxia-inducible factor-1α expression in cardiosphere-derived cells was adversely affected by aging.

CONCLUSIONS

Hypoxia-inducible factor-1α improves the functional potency of cardiosphere-derived cells to preserve myocardial function after myocardial infarction by enriching the cardiosphere-derived cells' secretome with cardioprotective factors. This strategy may be useful for improving the efficacy of allogeneic cell-based therapies in future clinical trials.

Scar-Degrading Endothelial Cells as a Treatment for Advanced Liver Fibrosis

Deposition of extracellular matrix (ECM) in the liver is an important feature of liver cirrhosis. Recovery from liver cirrhosis is physiologically challenging, partially due to the ECM in scar tissue showing resistance to cell-mediated degradation by secreted matrix metalloproteinases (MMPs). Here, a cell-mediated ECM-degradation screening system (CEDSS) in vitro is constructed for high-throughput searching for cells with tremendous degradation ability. ECM-degrading liver sinusoidal endothelial cells (dLSECs) are screened using CEDSS, which exhibit 17 times the ability to degrade collagen when compared to other cells. The degradation ability of dLSECs is mediated by the upregulation of MMP9. In particular, mRNA expression of MMP9 shows an 833-fold increase in dLSECs compared to normal endothelial cells (nLSECs), and MMP9 is regulated by transcription factor c-Fos. In vivo, single intrasplenic injection of dLSECs alleviates advanced liver fibrosis in mice, while intraperitoneal administration of liver-targeting peptide-modified dLSECs shows enhanced fibrosis-targeting effects. Degradative human umbilical vein endothelial cells (dHUVECs) prove their enhanced potential of clinical translation. Together, these results highlight the potential of ECM-degrading endothelial cells in alleviating advanced liver fibrosis, thus providing remarkable insights in the development of ECM-targeting therapeutics.

Computational analysis of serum-derived extracellular vesicle miRNAs in juvenile sheep model of single stage Fontan procedure

Patients with single ventricle heart defects requires a series of staged open-heart procedures, termed Fontan palliation. However, while lifesaving, these operations are associated with significant morbidity and early mortality. The attendant complications are thought to arise in response to the abnormal hemodynamics induced by Fontan palliation, although the pathophysiology underlying these physicochemical changes in cardiovascular and other organs remain unknown. Here, we investigated the microRNA (miRNA) content in serum and serum-derived extracellular vesicles (EVs) by sequencing small RNAs from a physiologically relevant sheep model of the Fontan operation. The differential expression analysis identified the enriched miRNA clusters in (1) serum vs. serum-derived EVs and (2) pre-Fontan EVs vs. post-Fontan EVs. Metascape analysis showed that the overexpressed subset of EV miRNAs by Fontan procedure target liver-specific cells, underscoring a potentially important pathway involved in the liver dysfunction that occurs as a consequence of Fontan palliation. We also found that post-Fontan EV miRNAs were associated with senescence and cell death, whereas pre-Fontan EV miRNAs were associated with stem cell maintenance and epithelial-to-mesenchymal transition. This study shows great potential to identify novel circulating EV biomarkers from Fontan sheep serum that may be used for the diagnosis, prognosis, and therapeutics for patients that have undergone Fontan palliation.

Unlocking the Potential of Induced Pluripotent Stem Cells for Wound Healing: The Next Frontier of Regenerative Medicine

Significance: Nonhealing wounds are a significant burden for the health care system all over the world. Existing treatment options are not enough to promote healing, highlighting the urgent need for improved therapies. In addition, the current advancements in tissue-engineered skin constructs and stem cell-based therapies are facing significant hurdles due to the absence of a renewable source of functional cells. Recent Advances: Induced pluripotent stem cell technology (iPSC) is emerging as a novel tool to develop the next generation of personalized medicine for the treatment of chronic wounds. The iPSC provides unlimited access to various skin cells to generate complex personalized three-dimensional skin constructs for disease modeling and autologous grafts. Furthermore, the iPSC-based therapies can target distinct wound healing phases and have shown accelerating wound closure by enhancing angiogenesis, cell migration, tissue regeneration, and modulating inflammation. Critical Issues: Since the last decade, iPSC has been revolutionizing the field of wound healing and skin tissue engineering. Despite the current progress, safety and heterogeneity among iPSC lines are still major hurdles in addition to the lack of large animal studies. These challenges need to be addressed before translating an iPSC-based therapy to the clinic. Future Directions: Future considerations should be given to performing large animal studies to check the safety and efficiency of iPSC-based therapy in a wound healing setup. Furthermore, strategies should be developed to overcome variation between hiPSC lines, develop an efficient manufacturing process for iPSC-derived products, and generate complex skin constructs with vasculature and skin appendages.

Single-Cell RNA Sequencing Reveals Distinct Cardiac-Derived Stromal Cell Subpopulations

Human cardiac-derived c-kit+ stromal cells (CSCs) have demonstrated efficacy in preclinical trials for the treatment of heart failure and myocardial dysfunction. Unfortunately, large variability in patient outcomes and cell populations remains a problem. Previous research has demonstrated that the reparative capacity of CSCs may be linked to the age of the cells: CSCs derived from neonate patients increase cardiac function and reduce fibrosis. However, age-dependent differences between CSC populations have primarily been explored with bulk sequencing methods. In this work, we hypothesized that differences in CSC populations and subsequent cell therapy outcomes may arise from differing cell subtypes within donor CSC samples. We performed single-cell RNA sequencing on four neonatal CSC (nCSC) and five child CSC (cCSC) samples. Subcluster analysis revealed cCSC-enriched clusters upregulated in several fibrosis- and immune response-related genes. Module-based analysis identified upregulation of chemotaxis and ribosomal activity-related genes in nCSCs and upregulation of immune response and fiber synthesis genes in cCSCs. Further, we identified versican and integrin alpha 2 as potential markers for a fibrotic cell subtype. By investigating differences in patient-derived CSC populations at the single-cell level, this research aims to identify and characterize CSC subtypes to better optimize CSC-based therapy and improve patient outcomes.

Characterization of Exosomes and Exosomal RNAs Isolated from Post-Mortem Body Fluids for Molecular Forensic Diagnosis

Exosomes have been mainly studied for their potential applications in biomarker detection and drug delivery for diagnosis and treatment. However, in the field of forensic research, the potential value of exosomes derived from post-mortem body fluids has not been investigated to date. Here, we isolated the exosomes and exosomal RNAs from post-mortem body fluids, including cardiac blood, pericardial fluid, and urine. We also compared commercial exosome isolation kits to determine the optimal method for post-mortem exosome isolation. Transmission electron microscopy (TEM), the Agilent bioanalyzer system, and western blotting were used to evaluate the efficiencies of alternative isolation methods and the characteristics of isolated exosomes. There were no significant differences between exosomes obtained from post-mortem and ante-mortem body fluids in the expression of exosome surface markers or morphology. The exosomes were well-preserved even under simulated post-mortem conditions. Among the isolation procedures tested, the membrane affinity column-based method was the most suitable for post-mortem exosomal RNA isolation. These results suggest that exosomes are well-preserved in post-mortem body fluids and could be utilized for forensic diagnosis.

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.

Donor extracellular vesicle trafficking via the pleural space represents a novel pathway for allorecognition after lung transplantation

Restoration of lymphatic drainage across the bronchial anastomosis after lung transplantation requires several weeks. As donor antigen and antigen presenting cell trafficking via lymphatics into graft-draining lymph nodes is an important component of the alloresponse, alternative pathways must exist that account for rapid rejection after pulmonary transplantation. Here, we describe a novel allorecognition pathway mediated through donor extracellular vesicle (EV) trafficking to mediastinal lymph nodes via the pleural space. Pleural fluid collected early after lung transplantation in rats and humans contains donor-specific EVs. In a fully MHC mismatched rat model of lung transplantation, we demonstrate EVs carrying donor antigen preferentially accumulate in mediastinal lymph nodes and colocalize with MHC II expressing cells within 4 h of engraftment. Injection of allogeneic EVs into pleural space of syngeneic lung transplant recipients confirmed their selective trafficking to mediastinal lymph nodes and resulted in activation of T cells in mediastinal, but not peripheral lymph nodes. Thus, we have uncovered an alternative pathway of donor antigen trafficking where pulmonary EVs released into the pleural space traffic to locoregional lymph nodes via pleural lymphatics. This pathway obviates the need for restoration of lymphatics across the bronchial anastomosis for trafficking of donor antigen to draining lymph nodes.

Functional cargos of exosomes derived from Flk-1+ vascular progenitors enable neurulation and ameliorate embryonic anomalies in diabetic pregnancy

Various types of progenitors initiate individual organ formation and their crosstalk orchestrates morphogenesis for the entire embryo. Here we show that progenitor exosomal communication across embryonic organs occurs in normal development and is altered in embryos of diabetic pregnancy. Endoderm fibroblast growth factor 2 (FGF2) stimulates mesoderm Flk-1+ vascular progenitors to produce exosomes containing the anti-stress protein Survivin. These exosomes act on neural stem cells of the neuroepithelium to facilitate neurulation by inhibiting cellular stress and apoptosis. Maternal diabetes causes Flk-1+ progenitor dysfunction by suppressing FGF2 through DNA hypermethylation. Restoring endoderm FGF2 prevents diabetes-induced survivin reduction in Flk-1+ progenitor exosomes. Transgenic Survivin expression in Flk-1+ progenitors or in utero delivery of survivin-enriched exosomes restores cellular homeostasis and prevents diabetes-induced neural tube defects (NTDs), whereas inhibiting exosome production induces NTDs. Thus, functional inter-organ communication via Flk-1 exosomes is vital for neurulation and its disruption leads to embryonic anomalies.

Comparative computational RNA analysis of cardiac-derived progenitor cells and their extracellular vesicles

Stem/progenitor cells, including cardiac-derived c-kit+ progenitor cells (CPCs), are under clinical evaluation for treatment of cardiac disease. Therapeutic efficacy of cardiac cell therapy can be attributed to paracrine signaling and the release of extracellular vesicles (EVs) carrying diverse cargo molecules. Despite some successes and demonstrated safety, large variation in cell populations and preclinical/clinical outcomes remains a problem. Here, we investigated this variability by sequencing coding and non-coding RNAs of CPCs and CPC-EVs from 30 congenital heart disease patients and used machine learning methods to determine potential mechanistic insights. CPCs retained RNAs related to extracellular matrix organization and exported RNAs related to various signaling pathways to CPC-EVs. CPC-EVs are enriched in miRNA clusters related to cell proliferation and angiogenesis. With network analyses, we identified differences in non-coding RNAs which give insight into age-dependent functionality of CPCs. By taking a quantitative computational approach, we aimed to uncover sources of CPC cell therapy variability.

Human Adipose-Derived Stem Cell-Conditioned Medium Promotes Vascularization of Nanostructured Scaffold Transplanted into Nude Mice

Several studies have been conducted on the interaction between three-dimensional scaffolds and mesenchymal stem cells for the regeneration of damaged tissues. Considering that stem cells do not survive for sufficient time to directly sustain tissue regeneration, it is essential to develop cell-free systems to be applied in regenerative medicine. In this work, by in vivo experiments, we established that a collagen-nanostructured scaffold, loaded with a culture medium conditioned with mesenchymal stem cells derived from adipose tissue (hASC-CM), exerts a synergic positive effect on angiogenesis, fundamental in tissue regeneration. To this aim, we engrafted athymic BALB-C nude mice with four different combinations: scaffold alone; scaffold with hASCs; scaffold with hASC crude protein extract; scaffold with hASC-CM. After their removal, we verified the presence of blood vessels by optical microscopy and confirmed the vascularization evaluating, by real-time PCR, several vascular growth factors: CD31, CD34, CD105, ANGPT1, ANGPT2, and CDH5. Our results showed that blood vessels were absent in the scaffold grafted alone, while all the other systems appeared vascularized, a finding supported by the over-expression of CD31 and CDH5 mRNA. In conclusion, our data sustain the capability of hASC-CM to be used as a therapeutic cell-free approach for damaged tissue regeneration.

Circulating Donor Lung-specific Exosome Profiles Enable Noninvasive Monitoring of Acute Rejection in a Rodent Orthotopic Lung Transplantation Model

BACKGROUND

There is a critical need for development of biomarkers to noninvasively monitor for lung transplant rejection. We investigated the potential of circulating donor lung-specific exosome profiles for time-sensitive diagnosis of acute rejection in a rat orthotopic lung transplant model.

METHODS

Left lungs from Wistar transgenic rats expressing human CD63-GFP, an exosome marker, were transplanted into fully MHC-mismatched Lewis recipients or syngeneic controls. Recipient blood was collected between 4 h and 10 d after transplantation, and plasma was processed for exosome isolation by size exclusion column chromatography and ultracentrifugation. Circulating donor exosomes were profiled using antihuman CD63 antibody quantum dot on the nanoparticle detector and via GFP trigger on the nanoparticle flow cytometer.

RESULTS

In syngeneic controls, steady-state levels of circulating donor exosomes were detected at all posttransplant time points. Allogeneic grafts lost perfusion by day 8, consistent with acute rejection. Levels of circulating donor exosomes peaked on day 1, decreased significantly by day 2, and then reached baseline levels by day 3. Notably, decrease in peripheral donor exosome levels occurred before grafts had histological evidence of acute rejection.

CONCLUSIONS

Circulating donor lung-specific exosome profiles enable an early detection of acute rejection before histologic manifestation of injury to the pulmonary allograft. As acute rejection episodes are a major risk factor for the development of chronic lung allograft dysfunction, this biomarker may provide a novel noninvasive diagnostic platform that can translate into earlier therapeutic intervention for lung transplant patients.

A Novel, Cell-Free Therapy to Enter Our Hearts: The Potential Role of Small EVs in Prevention and Treatment of CVD

Heart disease constitutes one of the leading causes of morbidity and mortality worldwide. Current therapeutic techniques, such as interventional revascularization, although lifesaving, come along with myocardial injury related to the reperfusion itself, called ischemia-reperfusion injury, which is an added factor for increased morbidity. For that reason, there is an imperative need for novel therapies to be developed that would either prevent or treat myocardial injury. Extracellular vesicles (EVs), specifically small EVs (sEVs), have proven to be important mediators of intercellular communication. The fact that they carry information reflecting that of the parental cell makes them an ideal candidate for diagnostic purposes. sEVs derived from immunoregulatory cells, such as mesenchymal stem cells or cardiac progenitor cells, could also be used therapeutically to exert the primary immunomodulatory function but without carrying the side effects related to cell therapy. Furthermore, as a natural product, they have the added advantage of low immunogenicity, offering the potential for safe drug delivery. In the field of cardiology, there has been great interest in the therapeutic and diagnostic potential of sEVs with significant translational potential. Here, we review the potential use of sEVs in the context of myocardial ischemia and ischemia-reperfusion injury.

Synergistic Anti-Ageing through Senescent Cells Specific Reprogramming

In this review, we seek a novel strategy for establishing a rejuvenating microenvironment through senescent cells specific reprogramming. We suggest that partial reprogramming can produce a secretory phenotype that facilitates cellular rejuvenation. This strategy is desired for specific partial reprogramming under control to avoid tumour risk and organ failure due to loss of cellular identity. It also alleviates the chronic inflammatory state associated with ageing and secondary senescence in adjacent cells by improving the senescence-associated secretory phenotype. This manuscript also hopes to explore whether intervening in cellular senescence can improve ageing and promote damage repair, in general, to increase people's healthy lifespan and reduce frailty. Feasible and safe clinical translational protocols are critical in rejuvenation by controlled reprogramming advances. This review discusses the limitations and controversies of these advances' application (while organizing the manuscript according to potential clinical translation schemes) to explore directions and hypotheses that have translational value for subsequent research.

New paradigms in regenerative engineering: Emerging role of extracellular vesicles paired with instructive biomaterials

Mesenchymal stem cells (MSCs) have long been regarded as critical components of regenerative medicine strategies, given their multipotency and persistence in a variety of tissues. Recently, the specific role of MSCs in mediating regenerative outcomes has been attributed (in part) to secreted factors from transplanted cells, namely extracellular vesicles. This viewpoint manuscript highlights the promise of cell-derived extracellular vesicles as agents of regeneration, enhanced by synergy with appropriate biomaterials platforms. Extracellular vesicles are a potentially interesting regenerative tool to enhance the synergy between MSCs and biomaterials. As a result, we believe these technologies will improve patient outcomes through efficient therapeutic strategies resulting in predictable patient outcomes.

Epicardium-Derived Tbx18+ CDCs Transplantation Improve Heart Function in Infarcted Mice

Cardiosphere-derived cells (CDCs) constitute a cardiac stem cell pool, a promising therapeutics in treating myocardial infarction (MI). However, the cell source of CDCs remains unclear. In this study, we isolated CDCs directly from adult mouse heart epicardium named primary epicardium-derived CDCs (pECDCs), which showed a different expression profile compared with primary epicardial cells (pEpiCs). Interestingly, pECDCs highly expressed T-box transcription factor 18 (Tbx18) and showed multipotent differentiation ability in vitro. Human telomerase reverse transcriptase (hTERT) transduction could inhibit aging-induced pECDCs apoptosis and differentiation, thus keeping a better proliferation capacity. Furthermore, immortalized epicardium CDCs (iECDCs) transplantation extensively promote cardiogenesis in the infracted mouse heart. This study demonstrated epicardium-derived CDCs that may derive from Tbx18+ EpiCs, which possess the therapeutic potential to be applied to cardiac repair and regeneration and suggest a new kind of CDCs with identified origination that may be followed in the developing and injured heart.

Gingival mesenchymal stem cell-derived exosomes are immunosuppressive in preventing collagen-induced arthritis

Due to the unsatisfied effects of clinical drugs used in rheumatoid arthritis (RA), investigators shifted their focus on the biotherapy. Although human gingival mesenchymal stem cells (GMSC) have the potential to be used in treating RA, GMSC‐based therapy has some inevitable side effects such as immunogenicity and tumorigenicity. As one of the most important paracrine mediators, GMSC‐derived exosomes (GMSC‐Exo) exhibit therapeutic effects via immunomodulation in a variety of disease models, bypassing potential shortcomings of the direct use of MSCs. Furthermore, exosomes are not sensitive to freezing and thawing, and can be readily available for use. GMSC‐Exo has been reported to promote tissue regeneration and wound healing, but have not been reported to be effective against autoimmune diseases. We herein compare the immunomodulatory functions of GMSC‐Exo and GMSC in collagen‐induced arthritis (CIA) model and in vitro CD4⁺ T‐cell co‐culture model. The results show that GMSC‐Exo has the same or stronger effects compared with GMSC in inhibiting IL‐17A and promoting IL‐10, reducing incidences and bone erosion of arthritis, via inhibiting IL‐17RA‐Act1‐TRAF6‐NF‐κB signal pathway. Our results suggest that GMSC‐Exo has many advantages in treating CIA, and may offer a promising new cell‐free therapy strategy for RA and other autoimmune diseases.

Restoring Cardiac Functions after Myocardial Infarction-Ischemia/Reperfusion via an Exosome Anchoring Conductive Hydrogel

Both myocardial infarction (MI) and the follow-up reperfusion will lead to an inevitable injury to myocardial tissues, such as cardiac dysfunctions, fibrosis, and reduction of intercellular cell-to-cell interactions. Recently, exosomes (Exo) derived from stem cells have demonstrated a robust capability to promote angiogenesis and tissue repair. However, the short half-life of Exo and rapid clearance lead to insufficient therapeutic doses in the lesion area. Herein, an injectable conductive hydrogel is constructed to bind Exo derived from human umbilical cord mesenchymal stem cells to treat myocardial injuries after myocardial infarction-ischemia/reperfusion (MI-I/R). To this end, a hyperbranched epoxy macromer (EHBPE) grafted by an aniline tetramer (AT) was synthesized to cross-link thiolated hyaluronic acid (HA-SH) and thiolated Exo anchoring a CP05 peptide via an epoxy/thiol "click" reaction. The resulting Gel@Exo composite system possesses multiple features, such as controllable gelation kinetics, shear-thinning injectability, conductivity matching the native myocardium, soft and dynamic stability adapting to heartbeats, and excellent cytocompatibility. After being injected into injured hearts of rats, the hydrogel effectively prolongs the retention of Exo in the ischemic myocardium. The cardiac functions have been considerably improved by Gel@Exo administration, as indicated by the enhancing ejection fraction and fractional shortening, and reducing fibrosis area. Immunofluorescence staining and reverse transcription-polymerase chain reaction (RT-PCR) results demonstrate that the expression of cardiac-related proteins (Cx43, Ki67, CD31, and α-SMA) and genes (VEGF-A, VEGF-B, vWF, TGF-β1, MMP-9, and Serca2a) are remarkably upregulated. The conductive Gel@Exo system can significantly improve cell-to-cell interactions, promote cell proliferation and angiogenesis, and result in a prominent therapeutic effect on MI-I/R, providing a promising therapeutic method for injured myocardial tissues.

MicroRNAs and exosomes: Cardiac stem cells in heart diseases

Treating cardiovascular diseases with cardiac stem cells (CSCs) is a valid treatment among various stem cell-based therapies. With supplying the physiological need for cardiovascular cells as their main function, under pathological circumstances, CSCs can also reproduce the myocardial cells. Although studies have identified many of CSCs' functions, our knowledge of molecular pathways that regulate these functions is not complete enough. Either physiological or pathological studies have shown, stem cells proliferation and differentiation could be regulated by microRNAs (miRNAs). How miRNAs regulate CSC behavior is an interesting area of research that can help us study and control the function of these cells in vitro; an achievement that may be beneficial for patients with cardiovascular diseases. The secretome of stem and progenitor cells has been studied and it has been determined that exosomes are the main source of their secretion which are very small vesicles at the nanoscale and originate from endosomes, which are secreted into the extracellular space and act as key signaling organelles in intercellular communication. Mesenchymal stem cells, cardiac-derived progenitor cells, embryonic stem cells, induced pluripotent stem cells (iPSCs), and iPSC-derived cardiomyocytes release exosomes that have been shown to have cardioprotective, immunomodulatory, and reparative effects. Herein, we summarize the regulation roles of miRNAs and exosomes in cardiac stem cells.

Engineering Cardiac Small Extracellular Vesicle-Derived Vehicles with Thin-Film Hydration for Customized microRNA Loading

Cell therapies for myocardial infarction, including cardiac ckit+ progenitor cell (CPC) therapies, have been promising, with clinical trials underway. Recently, paracrine signaling, specifically through small extracellular vesicle (sEV) release, was implicated in cell-based cardiac repair. sEVs carry cardioprotective cargo, including microRNA (miRNA), within a complex membrane and improve cardiac outcomes similar to that of their parent cells. However, miRNA loading efficiency is low, and sEV yield and cargo composition vary with parent cell conditions, minimizing sEV potency. Synthetic mimics allow for cargo-loading control but consist of much simpler membranes, often suffering from high immunogenicity and poor stability. Here, we aim to combine the benefits of sEVs and synthetic mimics to develop sEV-like vesicles (ELVs) with customized cargo loading. We developed a modified thin-film hydration (TFH) mechanism to engineer ELVs from CPC-derived sEVs with pro-angiogenic miR-126 encapsulated. Characterization shows miR-126+ ELVs are similar in size and structure to sEVs. Upon administration to cardiac endothelial cells (CECs), ELV uptake is similar to sEVs too. Further, when functionally validated with a CEC tube formation assay, ELVs significantly improve tube formation parameters compared to sEVs. This study shows TFH-ELVs synthesized from sEVs allow for select miRNA loading and can improve in vitro cardiac outcomes.

Connecting different heart diseases through intercellular communication

Well-orchestrated intercellular communication networks are pivotal to maintaining cardiac homeostasis and to ensuring adaptative responses and repair after injury. Intracardiac communication is sustained by cell-cell crosstalk, directly via gap junctions (GJ) and tunneling nanotubes (TNT), indirectly through the exchange of soluble factors and extracellular vesicles (EV), and by cell-extracellular matrix (ECM) interactions. GJ-mediated communication between cardiomyocytes and with other cardiac cell types enables electrical impulse propagation, required to sustain synchronized heart beating. In addition, TNT-mediated organelle transfer has been associated with cardioprotection, whilst communication via EV plays diverse pathophysiological roles, being implicated in angiogenesis, inflammation and fibrosis. Connecting various cell populations, the ECM plays important functions not only in maintaining the heart structure, but also acting as a signal transducer for intercellular crosstalk. Although with distinct etiologies and clinical manifestations, intercellular communication derailment has been implicated in several cardiac disorders, including myocardial infarction and hypertrophy, highlighting the importance of a comprehensive and integrated view of complex cell communication networks. In this review, I intend to provide a critical perspective about the main mechanisms contributing to regulate cellular crosstalk in the heart, which may be considered in the development of future therapeutic strategies, using cell-based therapies as a paradigmatic example. This Review has an associated Future Leader to Watch interview with the author.

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.

Small extracellular vesicles containing miR-486-5p promote angiogenesis after myocardial infarction in mice and nonhuman primates

Stem cell-derived small extracellular vesicles (sEVs) promote angiogenesis after myocardial infarction (MI). However, the components of sEVs that contribute to these effects and the safety and efficiency of engineered sEV treatment for MI remain unresolved. Here, we observed improved cardiac function, enhanced vascular density, and smaller infarct size in mice treated with the sEVs from hypoxia-preconditioned (HP) mesenchymal stem cells (MSCs) (HP-sEVs) than in mice treated with normoxia-preconditioned (N) MSCs (N-sEVs). MicroRNA profiling revealed a higher abundance of miR-486-5p in HP-sEVs than in N-sEVs, and miR-486-5p inactivation abolished the benefit of HP-sEV treatment, whereas miR-486-5p up-regulation enhanced the benefit of N-sEV treatment. Matrix metalloproteinase 19 (MMP19) abundance was lower in HP-sEV-treated than N-sEV-treated mouse hearts but was enriched in cardiac fibroblasts (CFs), and Mmp19 was identified as one of the target genes of miR-486-5p. Conditioned medium from CFs that overexpressed miR-486-5p or silenced MMP19 increased the angiogenic activity of endothelial cells; however, medium from CFs that simultaneously overexpressed Mmp19 and miR-486-5p abolished this effect. Mmp19 silencing in CFs reduced the cleavage of extracellular vascular endothelial growth factor (VEGF). Furthermore, miR-486-5p-overexpressing N-sEV treatment promoted angiogenesis and cardiac recovery without increasing arrhythmia complications in a nonhuman primate (NHP) MI model. Collectively, this study highlights the key role of sEV miR-486-5p in promoting cardiac angiogenesis via fibroblastic MMP19-VEGFA cleavage signaling. Delivery of miR-486-5p-engineered sEVs safely enhanced angiogenesis and cardiac function in an NHP MI model and may promote cardiac repair.

A Small Vimentin-Binding Molecule Blocks Cancer Exosome Release and Reduces Cancer Cell Mobility

Vimentin is an intermediate filament protein with diverse roles in health and disease far beyond its structural functions. Exosomes or small extracellular vesicles (sEVs) are key mediators for intercellular communication, contributing to tissue homeostasis and the progression of various diseases, especially the metastasis of cancers. In this study, we evaluated a novel vimentin-binding compound (R491) for its anti-cancer activities and its roles in cancer exosome release. The compound R491 induced a rapid and reversible intracellular vacuolization in various types of cancer cells. This phenotype did not result in an inhibition of cancer cell growth, which was consistent with our finding from a protein array that R491 did not reduce levels of major oncoproteins in cancer cells. Morphological and quantitative analyses on the intracellular vacuoles and extracellular exosomes revealed that in response to R491 treatment, the exosomes released from the cells were significantly reduced, while the exosomes retained as intra-luminal vesicles inside the cells were subsequently degraded. Vim^+/− cells had lower amounts of vimentin and accordingly, lower amounts of both the retained and the released exosomes than Vim^+/+ cells had, while the vimentin-binding compound R491 inhibited only the release of exosomes. Further functional tests showed that R491 significantly reduced the migration and invasion of cancer cells in vitro and decreased the amount of exosome in the blood in mice. Our study suggests that vimentin promotes exosome release, and small-molecule compounds that target vimentin are able to both block cancer exosome release and reduce cancer cell motility, and therefore could have potential applications for inhibiting cancer invasive growth.

Cardiosphere-derived exosomal microRNAs for myocardial repair in pediatric dilated cardiomyopathy

Although cardiosphere-derived cells (CDCs) improve cardiac function and outcomes in patients with single ventricle physiology, little is known about their safety and therapeutic benefit in children with dilated cardiomyopathy (DCM). We aimed to determine the safety and efficacy of CDCs in a porcine model of DCM and translate the preclinical results into this patient population. A swine model of DCM using intracoronary injection of microspheres created cardiac dysfunction. Forty pigs were randomized as preclinical validation of the delivery method and CDC doses, and CDC-secreted exosome (CDCex)-mediated cardiac repair was analyzed. A phase 1 safety cohort enrolled five pediatric patients with DCM and reduced ejection fraction to receive CDC infusion. The primary endpoint was to assess safety, and the secondary outcome measure was change in cardiac function. Improved cardiac function and reduced myocardial fibrosis were noted in animals treated with CDCs compared with placebo. These functional benefits were mediated via CDCex that were highly enriched with proangiogenic and cardioprotective microRNAs (miRNAs), whereas isolated CDCex did not recapitulate these reparative effects. One-year follow-up of safety lead-in stage was completed with favorable profile and preliminary efficacy outcomes. Increased CDCex-derived miR-146a-5p expression was associated with the reduction in myocardial fibrosis via suppression of proinflammatory cytokines and transcripts. Collectively, intracoronary CDC administration is safe and improves cardiac function through CDCex in a porcine model of DCM. The safety lead-in results in patients provide a translational framework for further studies of randomized trials and CDCex-derived miRNAs as potential paracrine mediators underlying this therapeutic strategy.

Secretome signature of cardiopoietic cells echoed in rescued infarcted heart proteome

Stem cell paracrine activity is implicated in cardiac repair. Linkage between secretome functionality and therapeutic outcome was here interrogated by systems analytics of biobanked human cardiopoietic cells, a regenerative biologic in advanced clinical trials. Protein chip array identified 155 proteins differentially secreted by cardiopoietic cells with clinical benefit, expanded into a 520 node network, collectively revealing inherent vasculogenic properties along with cardiac and smooth muscle differentiation and development. Next generation RNA sequencing, refined by pathway analysis, pinpointed miR-146 dependent regulation upstream of the decoded secretome. Intracellular and extracellular integration unmasked commonality across cardio-vasculogenic processes. Mirroring the secretome pattern, infarcted hearts benefiting from cardiopoietic cell therapy restored the disease proteome engaging cardiovascular system functions. The cardiopoietic cell secretome thus confers a therapeutic molecular imprint on recipient hearts, with response informed by predictive systems profiling.

Dystrophin Deficiency Causes Progressive Depletion of Cardiovascular Progenitor Cells in the Heart

Duchenne muscular dystrophy (DMD) is a devastating condition shortening the lifespan of young men. DMD patients suffer from age-related dilated cardiomyopathy (DCM) that leads to heart failure. Several molecular mechanisms leading to cardiomyocyte death in DMD have been described. However, the pathological progression of DMD-associated DCM remains unclear. In skeletal muscle, a dramatic decrease in stem cells, so-called satellite cells, has been shown in DMD patients. Whether similar dysfunction occurs with cardiac muscle cardiovascular progenitor cells (CVPCs) in DMD remains to be explored. We hypothesized that the number of CVPCs decreases in the dystrophin-deficient heart with age and disease state, contributing to DCM progression. We used the dystrophin-deficient mouse model (mdx) to investigate age-dependent CVPC properties. Using quantitative PCR, flow cytometry, speckle tracking echocardiography, and immunofluorescence, we revealed that young mdx mice exhibit elevated CVPCs. We observed a rapid age-related CVPC depletion, coinciding with the progressive onset of cardiac dysfunction. Moreover, mdx CVPCs displayed increased DNA damage, suggesting impaired cardiac muscle homeostasis. Overall, our results identify the early recruitment of CVPCs in dystrophic hearts and their fast depletion with ageing. This latter depletion may participate in the fibrosis development and the acceleration onset of the cardiomyopathy.