Exosomes in Myocardial Repair: Advances and Challenges in the Development of Next-Generation Therapeutics

Extracellular vesicles transport RNA between cells: Unraveling their dual role in diagnostics and therapeutics

Modern methods of molecular diagnostics and therapy have revolutionized the field of medicine in recent years by providing more precise and effective tools for detecting and treating diseases. This progress includes a growing exploration of the body's secreted vesicles, known as extracellular vesicles (EVs), for both diagnostic and therapeutic purposes. EVs are a heterogeneous population of lipid bilayer vesicles secreted by almost every cell type studied so far. They are detected in body fluids and conditioned culture media from living cells. EVs play a crucial role in communication between cells and organs, both locally and over long distances. They are recognized for their ability to transport endogenous RNA and proteins between cells, including messenger RNA (mRNA), microRNA (miRNA), misfolded neurodegenerative proteins, and several other biomolecules. This review explores the dual utilization of EVs, serving not only for diagnostic purposes but also as a platform for delivering therapeutic molecules to cells and tissues. Through an exploration of their composition, biogenesis, and selective cargo packaging, we elucidate the intricate mechanisms behind RNA transport between cells via EVs, highlighting their potential use for both diagnostic and therapeutic applications. Finally, it addresses challenges and outlines prospective directions for the clinical utilization of EVs.

An injectable exosome-loaded hyaluronic acid-polylysine hydrogel for cardiac repair via modulating oxidative stress and the inflammatory microenvironment

Myocardial infarction (MI) is a serious cardiovascular disease with complex complications and high lethality. Currently, exosome (Exo) therapy has emerged as a promising treatment of ischemic MI due to its antioxidant, anti-inflammatory, and vascular abilities. However, traditional Exo delivery lacks spatiotemporal precision and targeting of microenvironment modulation, making it difficult to localize the lesion site for sustained effects. In this study, an injectable oxidized hyaluronic acid-polylysine (OHA-PL) hydrogel was developed to conveniently load adipose-derived mesenchymal stem cell exosomes (ADSC-Exos) and improve their retention under physiological conditions. The OHA-PL@Exo hydrogel with high spatiotemporal precision is transplanted minimally invasively into the ischemic myocardium to scavenge intracellular and extracellular reactive oxygen species, regulate macrophage polarization, and attenuate inflammation in the early phase of MI. In addition, this synergistic microenvironment modulation can effectively reduce myocardial fibrosis and ventricular remodeling, promote angiogenesis, and restore electrophysiological function in the late stage of MI. Therefore, this hyaluronic acid-polylysine to deliver exosomes has become a promising therapeutic strategy for myocardial repair.

Exosomes based strategies for cardiovascular diseases: Opportunities and challenges

Exosomes, as nanoscale extracellular vesicles (EVs), are secreted by all types of cells to facilitate intercellular communication in living organisms. After being taken up by neighboring or distant cells, exosomes can alter the expression levels of target genes in recipient cells and thereby affect their pathophysiological outcomes depending on payloads encapsulated therein. The functions and mechanisms of exosomes in cardiovascular diseases have attracted much attention in recent years and are thought to have cardioprotective and regenerative potential. This review summarizes the biogenesis and molecular contents of exosomes and details the roles played by exosomes released from various cells in the progression and recovery of cardiovascular disease. The review also discusses the current status of traditional exosomes in cardiovascular tissue engineering and regenerative medicine, pointing out several limitations in their application. It emphasizes that some of the existing emerging industrial or bioengineering technologies are promising to compensate for these shortcomings, and the combined application of exosomes and biomaterials provides an opportunity for mutual enhancement of their performance. The integration of exosome-based cell-free diagnostic and therapeutic options will contribute to the further development of cardiovascular regenerative medicine.

Exosome Therapy: A Novel Approach for Enhancing Estrogen Levels in Perimenopause

Perimenopause significantly impacts women's health globally, often managed with hormone replacement therapy (HRT) despite the associated risks. This study explores a novel alternative exosome therapy, aimed at stimulating estrogen production in ovarian tissues, thus offering a potential non-hormonal treatment for perimenopausal symptoms. Employing ex vivo methodologies, ovarian cortex specimens from perimenopausal women were treated with exosomes derived from human umbilical cord mesenchymal stem cells and cultured under specific conditions (patent number: PCT/US2022/073467). The exosomes were produced under cyclic guanosine monophosphate (cGMP) conditions, ensuring high safety standards. Estrogen levels were quantified using enzyme-linked immunosorbent assay (ELISA), and gene expression changes in estrogen and follicle-stimulating hormone (FSH) receptors were assessed via quantitative polymerase chain reaction (PCR). Immunohistochemistry (IHC) was utilized to evaluate cellular proliferation and apoptotic markers. The results indicated a significant increase in estrogen levels and estrogen receptor-alpha (Erα) expression in treated tissues compared to controls. Additionally, a decrease in apoptotic markers and an increase in cellular proliferation markers were observed. These findings suggest that exosome therapy can effectively enhance estrogen production and modulate receptor sensitivity in perimenopausal ovarian tissues. This approach could serve as a safer alternative to HRT, aligning with the body's natural regulatory mechanisms and potentially offering a more effective treatment option for managing perimenopausal symptoms.

Human Aging and Age-Related Diseases: From Underlying Mechanisms to Pro-Longevity Interventions

As human life expectancy continues to rise, becoming a pressing global concern, it brings into focus the underlying mechanisms of aging. The increasing lifespan has led to a growing elderly population grappling with age-related diseases (ARDs), which strains healthcare systems and economies worldwide. While human senescence was once regarded as an immutable and inexorable phenomenon, impervious to interventions, the emerging field of geroscience now offers innovative approaches to aging, holding the promise of extending the period of healthspan in humans. Understanding the intricate links between aging and pathologies is essential in addressing the challenges presented by aging populations. A substantial body of evidence indicates shared mechanisms and pathways contributing to the development and progression of various ARDs. Consequently, novel interventions targeting the intrinsic mechanisms of aging have the potential to delay the onset of diverse pathological conditions, thereby extending healthspan. In this narrative review, we discuss the most promising methods and interventions aimed at modulating aging, which harbor the potential to mitigate ARDs in the future. We also outline the complexity of senescence and review recent empirical evidence to identify rational strategies for promoting healthy aging.

Stem cells-derived exosomes as cardiac regenerative agents

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

Advancing cardiac regeneration through 3D bioprinting: methods, applications, and future directions

Cardiovascular diseases (CVDs) represent a paramount global mortality concern, and their prevalence is on a relentless ascent. Despite the effectiveness of contemporary medical interventions in mitigating CVD-related fatality rates and complications, their efficacy remains curtailed by an array of limitations. These include the suboptimal efficiency of direct cell injection and an inherent disequilibrium between the demand and availability of heart transplantations. Consequently, the imperative to formulate innovative strategies for cardiac regeneration therapy becomes unmistakable. Within this context, 3D bioprinting technology emerges as a vanguard contender, occupying a pivotal niche in the realm of tissue engineering and regenerative medicine. This state-of-the-art methodology holds the potential to fabricate intricate heart tissues endowed with multifaceted structures and functionalities, thereby engendering substantial promise. By harnessing the prowess of 3D bioprinting, it becomes plausible to synthesize functional cardiac architectures seamlessly enmeshed with the host tissue, affording a viable avenue for the restitution of infarcted domains and, by extension, mitigating the onerous yoke of CVDs. In this review, we encapsulate the myriad applications of 3D bioprinting technology in the domain of heart tissue regeneration. Furthermore, we usher in the latest advancements in printing methodologies and bioinks, culminating in an exploration of the extant challenges and the vista of possibilities inherent to a diverse array of approaches.

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

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

Detailed role of mesenchymal stem cell (MSC)-derived exosome therapy in cardiac diseases

Coronary heart disease (CHD) continues to be the leading cause of morbidity and mortality. There are numerous therapeutic reperfusion methods, including thrombolytic therapy, primary percutaneous coronary intervention, and anti-remodeling drugs like angiotensin-converting enzyme inhibitors and beta-blockers. Despite this, there is no pharmacological treatment that can effectively stop cardiomyocyte death brought on by myocardial ischemia/reperfusion (I/R) injury. For the purpose of regenerating cardiac tissue, mesenchymal stem cell (MSC) therapy has recently gained more attention. The pleiotropic effects of MSCs are instead arbitrated by the secretion of soluble paracrine factors and are unrelated to their capacity for differentiation. One of these paracrine mediators is the extracellular vesicle known as an exosome. Exosomes deliver useful cargo to recipient cells from MSCs, including peptides, proteins, cytokines, lipids, miRNA, and mRNA molecules. Exosomes take part in intercellular communication processes and help tissues and organs that have been injured or are ill heal. Exosomes alone were found to be the cause of MSCs' therapeutic effects in a variety of animal models, according to studies. Here, we have focused on the recent development in the therapeutic capabilities of exosomal MSCs in cardiac diseases.

Role of long noncoding RNAs in pathological cardiac remodeling after myocardial infarction: An emerging insight into molecular mechanisms and therapeutic potential

Myocardial infarction (MI) is the leading cause of heart failure (HF), accounting for high mortality and morbidity worldwide. As a consequence of ischemia/reperfusion injury during MI, multiple cellular processes such as oxidative stress-induced damage, cardiomyocyte death, and inflammatory responses occur. In the next stage, the proliferation and activation of cardiac fibroblasts results in myocardial fibrosis and HF progression. Therefore, developing a novel therapeutic strategy is urgently warranted to restrict the progression of pathological cardiac remodeling. Recently, targeting long non-coding RNAs (lncRNAs) provided a novel insight into treating several disorders. In this regard, numerous investigations have indicated that several lncRNAs could participate in the pathogenesis of MI-induced cardiac remodeling, suggesting their potential therapeutic applications. In this review, we summarized lncRNAs displayed in the pathophysiology of cardiac remodeling after MI, emphasizing molecular mechanisms. Also, we highlighted the possible translational role of lncRNAs as therapeutic targets for this condition and discussed the potential role of exosomes in delivering the lncRNAs involved in post-MI cardiac remodeling.

The Role of Exosomes in Upper-Extremity Tissue Regeneration

Exosomes are cell-free membrane vesicles secreted by a wide variety of cells as secretomes into the extracellular matrix. Alongside facilitating intercellular communication, exosomes carry various bioactive molecules consisting of nucleic acids, proteins, and lipids. Exosome applications have increased in popularity by overcoming the disadvantages of mesenchymal stem cell therapies. Despite this, a better understanding of the underlying mechanisms of action of exosomes is necessary prior to clinical application in upper-extremity tissue regeneration. The purpose of this review is to introduce the concept of exosomes and their possible applications in upper-extremity tissue regeneration, detail the shortcomings of current exosome research, and explore their potential clinical application in the upper extremity.

Cell-Specific mRNA Therapeutics for Cardiovascular Diseases and Regeneration

Cardiovascular diseases (CVDs) represent a significant global health burden, demanding innovative therapeutic approaches. In recent years, mRNA therapeutics have emerged as a promising strategy to combat CVDs effectively. Unlike conventional small-molecule drugs, mRNA therapeutics enable the direct modulation of cellular functions by delivering specific mRNA molecules to target cells. This approach offers unprecedented advantages, including the ability to harness endogenous cellular machinery for protein synthesis, thus allowing precise control over gene expression without insertion into the genome. This review summarizes the current status of the potential of cell-specific mRNA therapeutics in the context of cardiovascular diseases. First, it outlines the challenges associated with traditional CVD treatments and emphasizes the need for targeted therapies. Subsequently, it elucidates the underlying principles of mRNA therapeutics and the development of advanced delivery systems to ensure cell-specificity and enhanced efficacy. Notably, innovative delivery methods such as lipid nanoparticles and exosomes have shown promise in improving the targeted delivery of mRNA to cardiac cells, activated fibroblasts, and other relevant cell types. Furthermore, the review highlights the diverse applications of cell-specific mRNA therapeutics in addressing various aspects of cardiovascular diseases, including atherosclerosis, myocardial infarction, heart failure, and arrhythmias. By modulating key regulatory genes involved in cardiomyocyte proliferation, inflammation, angiogenesis, tissue repair, and cell survival, mRNA therapeutics hold the potential to intervene at multiple stages of CVD pathogenesis. Despite its immense potential, this abstract acknowledges the challenges in translating cell-specific mRNA therapeutics from preclinical studies to clinical applications like off-target effects and delivery. In conclusion, cell-specific mRNA therapeutics have emerged as a revolutionary gene therapy approach for CVD, offering targeted interventions with the potential to significantly improve patient outcomes.

Recent Progress in Prompt Molecular Detection of Exosomes Using CRISPR/Cas and Microfluidic-Assisted Approaches Toward Smart Cancer Diagnosis and Analysis

Exosomes are essential indicators of molecular mechanisms involved in interacting with cancer cells and the tumor environment. As nanostructures based on lipids and nucleic acids, exosomes provide a communication pathway for information transfer by transporting biomolecules from the target cell to other cells. Importantly, these extracellular vesicles are released into the bloodstream by the most invasive cells, i. e., cancer cells; in this way, they could be considered a promising specific biomarker for cancer diagnosis. In this matter, CRISPR-Cas systems and microfluidic approaches could be considered practical tools for cancer diagnosis and understanding cancer biology. CRISPR-Cas systems, as a genome editing approach, provide a way to inactivate or even remove a target gene from the cell without affecting intracellular mechanisms. These practical systems provide vital information about the factors involved in cancer development that could lead to more effective cancer treatment. Meanwhile, microfluidic approaches can also significantly benefit cancer research due to their proper sensitivity, high throughput, low material consumption, low cost, and advanced spatial and temporal control. Thereby, employing CRISPR-Cas- and microfluidics-based approaches toward exosome monitoring could be considered a valuable source of information for cancer therapy and diagnosis. This review assesses the recent progress in these promising diagnosis approaches toward accurate cancer therapy and in-depth study of cancer cell behavior.

New Insights into Cardiovascular Diseases Treatment Based on Molecular Targets

Cardiovascular diseases (CVDs) which consist of ischemic heart disease, stroke, heart failure, peripheral arterial disease, and several other cardiac and vascular conditions are one of the most common causes of death worldwide and often co-occur with diabetes mellitus and lipid disorders which worsens the prognosis and becomes a therapeutic challenge. Due to the increasing number of patients with CVDs, we need to search for new risk factors and pathophysiological changes to create new strategies for preventing, diagnosing, and treating not only CVDs but also comorbidities like diabetes mellitus and lipid disorders. As increasing amount of patients suffering from CVDs, there are many therapies which focus on new molecular targets like proprotein convertase subtilisin/kexin type 9 (PCSK9), angiopoietin-like protein 3, ATP-citrate lyase, or new technologies such as siRNA in treatment of dyslipidemia or sodium-glucose co-transporter-2 and glucagon-like peptide-1 in treatment of diabetes mellitus. Both SGLT-2 inhibitors and GLP-1 receptor agonists are used in the treatment of diabetes, however, they proved to have a beneficial effect in CVDs as well. Moreover, a significant amount of evidence has shown that exosomes seem to be associated with myocardial ischaemia and that exosome levels correlate with the severity of myocardial injury. In our work, we would like to focus on the above mechanisms. The knowledge of them allows for the appearance of new strategies of treatment among patients with CVDs.

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

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

Exosome-bearing hydrogels and cardiac tissue regeneration

BACKGROUND

In recent years, cardiovascular disease in particular myocardial infarction (MI) has become the predominant cause of human disability and mortality in the clinical setting. The restricted capacity of adult cardiomyocytes to proliferate and restore the function of infarcted sites is a challenging issue after the occurrence of MI. The application of stem cells and byproducts such as exosomes (Exos) has paved the way for the alleviation of cardiac tissue injury along with conventional medications in clinics. However, the short lifespan and activation of alloreactive immune cells in response to Exos and stem cells are the main issues in patients with MI. Therefore, there is an urgent demand to develop therapeutic approaches with minimum invasion for the restoration of cardiac function.

MAIN BODY

Here, we focused on recent data associated with the application of Exo-loaded hydrogels in ischemic cardiac tissue. Whether and how the advances in tissue engineering modalities have increased the efficiency of whole-based and byproducts (Exos) therapies under ischemic conditions. The integration of nanotechnology and nanobiology for designing novel smart biomaterials with therapeutic outcomes was highlighted.

CONCLUSION

Hydrogels can provide suitable platforms for the transfer of Exos, small molecules, drugs, and other bioactive factors for direct injection into the damaged myocardium. Future studies should focus on the improvement of physicochemical properties of Exo-bearing hydrogel to translate for the standard treatment options.

Host and Pathogen-Directed Therapies against Microbial Infections Using Exosome- and Antimicrobial Peptide-derived Stem Cells with a Special look at Pulmonary Infections and Sepsis

Microbial diseases are a great threat to global health and cause considerable mortality and extensive economic losses each year. The medications for treating this group of diseases (antibiotics, antiviral, antifungal drugs, etc.) directly attack the pathogenic agents by recognizing the target molecules. However, it is necessary to note that excessive use of any of these drugs can lead to an increase in microbial resistance and infectious diseases. New therapeutic methods have been studied recently using emerging drugs such as mesenchymal stem cell-derived exosomes (MSC-Exos) and antimicrobial peptides (AMPs), which act based on two completely different strategies against pathogens including Host-Directed Therapy (HDT) and Pathogen-Directed Therapy (PDT), respectively. In the PDT approach, AMPs interact directly with pathogens to interrupt their intrusion, survival, and proliferation. These drugs interact directly with the cell membrane or intracellular components of pathogens and cause the death of pathogens or inhibit their replication. The mechanism of action of MSC-Exos in HDT is based on immunomodulation and regulation, promotion of tissue regeneration, and reduced host toxicity. This review studies the potential of mesenchymal stem cell-derived exosomes/ATPs therapeutic properties against microbial infectious diseases especially pulmonary infections and sepsis.

Obesity phenotypes and cardiovascular risk: From pathophysiology to clinical management

Obesity epidemic reached the dimensions of a real global health crisis with more than one billion people worldwide living with obesity. Multiple obesity-related mechanisms cause structural, functional, humoral, and hemodynamic alterations with cardiovascular (CV) deleterious effects. A correct assessment of the cardiovascular risk in people with obesity is critical for reducing mortality and preserving quality of life. The correct identification of the obesity status remains difficult as recent evidence suggest that different phenotypes of obesity exist, each one associated with different degrees of CV risk. Diagnosis of obesity cannot depend only on anthropometric parameters but should include a precise assessment of the metabolic status. Recently, the World Heart Federation and World Obesity Federation provided an action plan for management of obesity-related CV risk and mortality, stressing for the instauration of comprehensive structured programs encompassing multidisciplinary teams. In this review we aim at providing an updated summary regarding the different obesity phenotypes, their specific effects on CV risk and differences in clinical management.

Stem cells-derived exosomes alleviate neurodegeneration and Alzheimer's pathogenesis by ameliorating neuroinflamation, and regulating the associated molecular pathways

Amyloid beta (Aβ) aggregation and tau hyper phosphorylation (p-tau) are key molecular factors in Alzheimer's disease (AD). The abnormal formation and accumulation of Aβ and p-tau lead to the formation of amyloid plaques and neurofibrillary tangles (NFTs) which ultimately leads to neuroinflammation and neurodegeneration. β- and γ-secretases produce Aβ peptides via the amyloidogenic pathway, and several kinases are involved in tau phosphorylation. Exosomes, a recently developed method of intercellular communication, derived from neuronal stem cells (NSC-exos), are intriguing therapeutic options for AD. Exosomes have ability to cross the BBB hence highly recommended for brain related diseases and disorders. In the current study, we examined how NSC-exos could protect human neuroblastoma cells SH-SY5Y (ATCC CRL-2266). NSC-exos were derived from Human neural stem cells (ATCC-BYS012) by ultracentrifugation and the therapeutic effects of the NSC-exos were then investigated in vitro. NSC-exos controlled the associated molecular processes to drastically lower Aβ and p-tau. A dose dependent reduction in β- and γ-secretase, acetylcholinesterase, GSK3β, CDK5, and activated α-secretase activities was also seen. We further showed that BACE1, PSEN1, CDK5, and GSK-3β mRNA expression was suppressed and downregulated, while ADAM10 mRNA was increased. NSC- Exos downregulate NF-B/ERK/JNK-related signaling pathways in activated glial cells HMC3 (ATCC-CRL-3304) and reduce inflammatory mediators such iNOS, IL-1β, TNF-α, and IL-6, which are associated with neuronal inflammation. The NSC-exos therapy ameliorated the neurodegeneration of human neuroblastoma cells SH-SY5Y by enhancing viability. Overall, these findings support that exosomes produced from stem cells can be a neuro-protective therapy to alleviate AD pathology.

Application of stem cells in regeneration medicine

Regeneration is a complex process affected by many elements independent or combined, including inflammation, proliferation, and tissue remodeling. Stem cells is a class of primitive cells with the potentiality of differentiation, regenerate with self-replication, multidirectional differentiation, and immunomodulatory functions. Stem cells and their cytokines not only inextricably linked to the regeneration of ectodermal and skin tissues, but also can be used for the treatment of a variety of chronic wounds. Stem cells can produce exosomes in a paracrine manner. Stem cell exosomes play an important role in tissue regeneration, repair, and accelerated wound healing, the biological properties of which are similar with stem cells, while stem cell exosomes are safer and more effective. Skin and bone tissues are critical organs in the body, which are essential for sustaining life activities. The weak repairing ability leads a pronounced impact on the quality of life of patients, which could be alleviated by stem cell exosomes treatment. However, there are obstacles that stem cells and stem cells exosomes trough skin for improved bioavailability. This paper summarizes the applications and mechanisms of stem cells and stem cells exosomes for skin and bone healing. We also propose new ways of utilizing stem cells and their exosomes through different nanoformulations, liposomes and nanoliposomes, polymer micelles, microspheres, hydrogels, and scaffold microneedles, to improve their use in tissue healing and regeneration.

Stem cells derived exosomes and biomaterials to modulate autophagy and mend broken hearts

Autophagy maintains cellular homeostasis and plays a crucial role in managing pathological conditions including ischemic myocardial injury leading to heart failure (HF). Despite treatments, no intervention can replace lost cardiomyocytes. Stem cell therapy offers potential for post-myocardial infarction repair but struggles with poor cell retention due to immune rejection. In the search for effective therapies, stem cell-derived extracellular vesicles (EVs), especially exosomes, have emerged as promising tools. These tiny bioactive molecule carriers play vital roles in intercellular communication and tissue engineering. They offer numerous therapeutic benefits including modulating immune responses, promoting tissue repair, and boosting angiogenesis. Additionally, biomaterials provide a conducive 3D microenvironment for cell, exosome, and biomolecule delivery, and enhance heart muscle strength, making it a comprehensive cardiac repair strategy. In this regard, the current review delves into the intricate application of extracellular vesicles (EVs) and biomaterials for managing autophagy in the heart muscle during cardiac injury. Central to our investigation is the exploration of how these elements interact within the context of cardiac repair and regeneration. Additionally, this review also casts light on the formidable challenges that plague this field, such as the issues of safety, efficacy, controlled delivery, and acceptance of these therapeutic strategies for effective clinical translation. Addressing these challenges is crucial for unlocking the full therapeutic potential of EV and biomaterial-based therapies and ensuring their successful translation from bench to bedside.

Therapeutic Potential of Mesenchymal Stem Cell-Derived Extracellular Vesicles to Treat PCOS

Polycystic ovary syndrome (PCOS) is known as the most common endocrine disorder in women. Previously, we suggested that human mesenchymal stem cells (MSCs) can reverse the PCOS condition by secreting factors. Here, we evaluated the therapeutic capability of MSC-derived extracellular vesicles (EVs), also known as exosomes, in both in vitro and in vivo PCOS models. Exosomes were used to treat androgen-producing H293R cells and injected in a mouse model through intraovarian and intravenous injection into a letrozole (LTZ)-induced PCOS mouse model. We assessed the effects of the exosomes on androgen-producing cells or the PCOS mouse model by analyzing steroidogenic gene expression (quantitative real-time polymerase chain reaction (qRT-PCR)), body weight change, serum hormone levels, and fertility by pup delivery. Our data show the therapeutic effect of MSC-derived EVs for reversing PCOS conditions, including fertility issues. Interestingly, intravenous injection was more effective for serum glucose regulation, and an intraovarian injection was more effective for ovary restoration. Our study suggests that MSC-derived exosomes can be promising biopharmaceutics for treating PCOS conditions as a novel therapeutic option. Despite the fact that we need more validation in human patients, we may evaluate this novel treatment option for PCOS with the following clinical trials.

Proteomic analysis of transcription factors involved in the alteration of ischemic mouse heart as modulated by MSC exosomes

Mesenchymal stem cell (MSC) exosomes have been found to attenuate cardiac systolic and diastolic dysfunction in animal models of ischemia. Exosomes carry a plethora of active and inactive proteins as their cargo, which are readily available to the recipient cell for use in intracellular signaling pathways-depending on the stresses, such as ischemia or hypoxia. Among the exosomal proteins are the often-overlooked cargo of transcriptional regulators. These transcriptional regulators influence the transcriptome and subsequently the proteome of recipient cell. Here, we report the transcriptional factors and regulators differentially modulated and their potential role in modulating cardiac function in MSC exosome treated ischemic mice hearts. Our analysis shows ischemic stress modulating transcriptional regulators and factors such as HSF1 and HIF1A in the infarct and peri-infarct areas of ischemic hearts which is mitigated by MSC exosomes. Similarly, STAT3 and SMAD3 are also modulated by MSC exosomes. Interestingly, NOTCH1 and β-catenin were detected in the ischemic hearts. The differential expression of these regulators and factors drives changes in various biological process governed in the ischemic cardiac cells. We believe these studies will advance our understanding of cardiac dysfunction occurring in the ischemic hearts and lay the groundwork for further studies on the modulation of cardiac function during ischemia by MSC exosomes.

Biological Modification of Arrhythmogenic Substrates by Cell-Free Therapeutics

Ventricular arrhythmias (VAs) represent a major cause of sudden cardiac death and afflict patients with heart failure from both ischaemic and non-ischaemic origins, and inherited cardiomyopathies. Current VA management, including anti-arrhythmic medications, autonomic modulation, implantable cardioverter-defibrillator implantation, and catheter ablation, remains suboptimal. Catheter ablation may even cause significant cardiomyocyte loss. Cell-based therapies and exosome treatment have been proposed as promising strategies to lessen cardiomyocyte death, modulate immune reaction, and reduce myocardial scarring, and, therefore, are potentially beneficial in treating VAs. In this review, we summarise the current cornerstones of VA management. We also discuss recent advances and ongoing evidence regarding cell-based and exosome therapy, with special attention to VA treatment.

Comparison of the therapeutic effects between stem cells and exosomes in primary ovarian insufficiency: as promising as cells but different persistency and dosage

BACKGROUND

Primary ovarian insufficiency (POI) refers to the loss of ovarian function under the age of 40 and results in amenorrhea and infertility. Our previous studies have shown that transplantation of mesenchymal stem cells (MSCs) and MSC-derived exosomes in chemotherapy-induced POI mouse ovaries can reverse the POI and eventually achieve pregnancy. Based on our recent studies, MSC-derived exosomes have almost equal therapeutic potentials as transplanted MSCs. However, it is still unclear whether exosomes can completely replace MSCs in POI treatment. For the reliable application of cell-free treatment for POI patients using exosomes, there is a need to understand whether there is any outcome and effectiveness difference between MSC and MSC-derived exosome treatment.

METHODS

Comparing the therapeutic effect of intravenous injection using MSCs and equal amounts of exosomes in a POI mouse model will reveal the difference between the two therapeutic resources. In this study, we induced POI in C57/BL6 mice by chemotherapy (CXT) using a standard protocol. We then injected four different doses of MSCs or equal amounts of commercialized MSC-derived exosomes by retro-orbital injection post-CXT.

RESULT

After MSC/exosome treatment, tissue and serum samples were harvested to analyze molecular changes after treatment, while other mice in parallel experiments underwent breeding experiments to compare the restoration of fertility. Both the MSC- and exosome-treated groups had a restored estrous cycle and serum hormone levels compared to untreated POI mice. The pregnancy rate in the MSC-treated group was 60-100% after treatment, while the pregnancy rate in the exosome-treated group was 30-50% after treatment. Interestingly, in terms of long-term effects, MSC-treated mice still showed a 60-80% pregnancy rate in the second round of breeding, while the exosome-treated group became infertile again in the second round of breeding.

CONCLUSIONS

Although there were some differences in the efficacy between MSC treatment and exosome treatment, both treatments were able to achieve pregnancy in the POI mouse model. In conclusion, we report that MSC-derived exosomes are a promising therapeutic option to restore ovarian function in POI conditions similar to treatment with MSCs.

Target and Cell Therapy for Atherosclerosis and CVD

Cardiovascular diseases (CVD) and, in particular, atherosclerosis, remain the main cause of death in the world today. Unfortunately, in most cases, CVD therapy begins after the onset of clinical symptoms and is aimed at eliminating them. In this regard, early pathogenetic therapy for CVD remains an urgent problem in modern science and healthcare. Cell therapy, aimed at eliminating tissue damage underlying the pathogenesis of some pathologies, including CVD, by replacing it with various cells, is of the greatest interest. Currently, cell therapy is the most actively developed and potentially the most effective treatment strategy for CVD associated with atherosclerosis. However, this type of therapy has some limitations. In this review, we have tried to summarize the main targets of cell therapy for CVD and atherosclerosis in particular based on the analysis using the PubMed and Scopus databases up to May 2023.

Extracellular vesicles: Emerged as a promising strategy for regenerative medicine

Cell transplantation therapy has certain limitations including immune rejection and limited cell viability, which seriously hinder the transformation of stem cell-based tissue regeneration into clinical practice. Extracellular vesicles (EVs) not only possess the advantages of its derived cells, but also can avoid the risks of cell transplantation. EVs are intelligent and controllable biomaterials that can participate in a variety of physiological and pathological activities, tissue repair and regeneration by transmitting a variety of biological signals, showing great potential in cell-free tissue regeneration. In this review, we summarized the origins and characteristics of EVs, introduced the pivotal role of EVs in diverse tissues regeneration, discussed the underlying mechanisms, prospects, and challenges of EVs. We also pointed out the problems that need to be solved, application directions, and prospects of EVs in the future and shed new light on the novel cell-free strategy for using EVs in the field of regenerative medicine.

Frontier Review of the Molecular Mechanisms and Current Approaches of Stem Cell-Derived Exosomes

Exosomes are effective therapeutic vehicles that may transport their substances across cells. They are shown to possess the capacity to affect cell proliferation, migration, anti-apoptosis, anti-scarring, and angiogenesis, via the action of transporting molecular components. Possessing immense potential in regenerative medicine, exosomes, especially stem cell-derived exosomes, have the advantages of low immunogenicity, minimal invasiveness, and broad clinical applicability. Exosome biodistribution and pharmacokinetics may be altered, in response to recent advancements in technology, for the purpose of treating particular illnesses. Yet, prior to clinical application, it is crucial to ascertain the ideal dose and any potential negative consequences of an exosome. This review focuses on the therapeutic potential of stem cell-derived exosomes and further illustrates the molecular mechanisms that underpin their potential in musculoskeletal regeneration, wound healing, female infertility, cardiac recovery, immunomodulation, neurological disease, and metabolic regulation. In addition, we provide a summary of the currently effective techniques for isolating exosomes, and describe the innovations in biomaterials that improve the efficacy of exosome-based treatments. Overall, this paper provides an updated overview of the biological factors found in stem cell-derived exosomes, as well as potential targets for future cell-free therapeutic applications.

Comparison of extruded cell nanovesicles and exosomes in their molecular cargos and regenerative potentials

Extracellular vesicles (EVs) generated from mesenchymal stem cells (MSCs) play an essential role in modulating cell-cell communication and tissue regeneration. The clinical translation of EVs is constrained by the poor yield of EVs. Extrusion has recently become an effective technique for producing a large scale of nanovesicles (NVs). In this study, we systematically compared MSC NVs (from extrusion) and EVs (from natural secretion). Proteomics and RNA sequencing data revealed that NVs resemble MSCs more closely than EVs. Additionally, microRNAs in NVs are related to cardiac repair, fibrosis repression, and angiogenesis. Lastly, intravenous delivery of MSC NVs improved heart repair and cardiac function in a mouse model of myocardial infarction.

Electronic Supplementary Material

Supplementary material (Figs. S1-S4) is available in the online version of this article at 10.1007/s12274-023-5374-3.

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.

HuMSC-EV induce monocyte/macrophage mobilization to orchestrate neovascularization in wound healing process following radiation injury

This study aims to investigate the mechanisms of human mesenchymal stem cell-derived extracellular vesicles (HuMSC-EV)-induced proangiogenic paracrine effects after radiation injury. HuMSC-EV were locally administered in mice hindlimb following 80-Gy X-ray irradiation and animals were monitored at different time points. HuMSC-EV improved neovascularization of the irradiated tissue, by stimulating angiogenesis, normalizing cutaneous blood perfusion, and increasing capillary density and production of proangiogenic factors. HuMSC-EV also stimulated vasculogenesis by promoting the recruitment and differentiation of bone marrow progenitors. Moreover, HuMSC-EV improved arteriogenesis by increasing the mobilization of monocytes from the spleen and the bone marrow and their recruitment into the muscle, with a pro-inflammatory potential. Importantly, monocyte depletion by clodronate treatment abolished the proangiogenic effect of HuMSC-EV. The critical role of Ly6C(hi) monocyte subset in HuMSC-EV-induced neovascularization process was further confirmed using Ccr2^-/- mice. This study demonstrates that HuMSC-derived EV enhances the neovascularization process in the irradiated tissue by increasing the production of proangiogenic factors, promoting the recruitment of vascular progenitor cells, and the mobilization of innate cells to the injured site. These results support the concept that HuMSC-EV might represent a suitable alternative to stem cells for therapeutic neovascularization in tissue repair.

Extracellular Vesicles and Ischemic Cardiovascular Diseases

Characterized by coronary artery obstruction or stenosis, ischemic cardiovascular diseases as advanced stages of coronary heart diseases commonly lead to left ventricular aneurysm, ventricular septal defect, and mitral insufficiency. Extracellular vesicles (EVs) secreted by diverse cells in the body exert roles in cell-cell interactions and intrinsic cellular regulations. With a lipid double-layer membrane and biological components such as DNA, protein, mRNA, microRNAs (miRNA), and siRNA inside, the EVs function as paracrine signaling for the pathophysiology of ischemic cardiovascular diseases and maintenance of the cardiac homeostasis. Unlike stem cell transplantation with the potential tumorigenicity and immunogenicity, the EV-based therapeutic strategy is proposed to satisfy the demand for cardiac repair and regeneration while the circulating EVs detected by a noninvasive approach can act as precious biomarkers. In this chapter, we extensively summarize the cardioprotective functions of native EVs and bioengineered EVs released from stem cells, cardiomyocytes, cardiac progenitor cells (CPCs), endothelial cells, fibroblast, smooth muscle cells, and immune cells. In addition, the potential of EVs as robust molecule biomarkers is discussed for clinical diagnosis of ischemic cardiovascular disease, attributed to the same pathology of EVs as that of their origin. Finally, we highlight EV-based therapy as a biocompatible alternative to direct cell-based therapy for ischemic cardiovascular diseases.

Cell-Based and Selected Cell-Free Therapies for Myocardial Infarction: How Do They Compare to the Current Treatment Options?

Because of cardiomyocyte death or dysfunction frequently caused by myocardial infarction (MI), heart failure is a leading cause of morbidity and mortality in modern society. Paradoxically, only limited and non-curative therapies for heart failure or MI are currently available. As a result, over the past two decades research has focused on developing cell-based approaches promoting the regeneration of infarcted tissue. Cell-based therapies for myocardial regeneration include powerful candidates, such as multipotent stem cells (mesenchymal stem cells (MSCs), bone-marrow-derived stem cells, endothelial progenitor cells, and hematopoietic stem cells) and induced pluripotent stem cells (iPSCs). These possess unique properties, such as potency to differentiate into desired cell types, proliferation capacity, and patient specificity. Preclinical and clinical studies have demonstrated modest improvement in the myocardial regeneration and reduced infarcted areas upon transplantation of pluripotent or multipotent stem cells. Another cell population that need to be considered as a potential source for cardiac regeneration are telocytes found in different organs, including the heart. Their therapeutic effect has been studied in various heart pathologies, such as MI, arrhythmias, or atrial amyloidosis. The most recent cell-free therapeutic tool relies on the cardioprotective effect of complex cargo carried by small membrane-bound vesicles—exosomes—released from stem cells via exocytosis. The MSC/iPSC-derived exosomes could be considered a novel exosome-based therapy for cardiovascular diseases thanks to their unique content. There are also other cell-free approaches, e.g., gene therapy, or acellular cardiac patches. Therefore, our review provides the most recent insights into the novel strategies for myocardial repair based on the regenerative potential of different cell types and cell-free approaches.

New Approaches for Enhancement of the Efficacy of Mesenchymal Stem Cell-Derived Exosomes in Cardiovascular Diseases

Cardiovascular diseases (CVDs) remain a major health concern worldwide, where mesenchymal stem cells (MSCs) therapy gives great promise in their management through their regenerative and paracrine actions. In recent years, many studies have shifted from the use of transplanted stem cells to their secreted exosomes for the management of various CVDs and cardiovascular-related diseases including atherosclerosis, stroke, myocardial infarction, heart failure, peripheral arterial diseases, and pulmonary hypertension. In different models, MSC-derived exosomes have shown beneficial outcomes similar to cell therapy concerning regenerative and neovascular actions in addition to their anti-apoptotic, anti-remodeling, and anti-inflammatory actions. Compared with their parent cells, exosomes have also demonstrated several advantages, including lower immunogenicity and no risk of tumor formation. However, the maintenance of stability and efficacy of exosomes after in vivo transplantation is still a major concern in their clinical application. Recently, new approaches have been developed to enhance their efficacy and stability including their preconditioning before transplantation, use of genetically modified MSC-derived exosomes, or their utilization as a targeted drug delivery system. Herein, we summarized the use of MSC-derived exosomes as therapies in different CVDs in addition to recent advances for the enhancement of their efficacy in these conditions.

Nanomaterials-Mediated Therapeutics and Diagnosis Strategies for Myocardial Infarction

The alarming mortality and morbidity rate of myocardial infarction (MI) is becoming an important impetus in the development of early diagnosis and appropriate therapeutic approaches, which are critical for saving patients' lives and improving post-infarction prognosis. Despite several advances that have been made in the treatment of MI, current strategies are still far from satisfactory. Nanomaterials devote considerable contribution to tackling the drawbacks of conventional therapy of MI by improving the homeostasis in the cardiac microenvironment via targeting, immune modulation, and repairment. This review emphasizes the strategies of nanomaterials-based MI treatment, including cardiac targeting drug delivery, immune-modulation strategy, antioxidants and antiapoptosis strategy, nanomaterials-mediated stem cell therapy, and cardiac tissue engineering. Furthermore, nanomaterials-based diagnosis strategies for MI was presented in term of nanomaterials-based immunoassay and nano-enhanced cardiac imaging. Taken together, although nanomaterials-based strategies for the therapeutics and diagnosis of MI are both promising and challenging, such a strategy still explores the immense potential in the development of the next generation of MI treatment.

Expression of Extracellular Vesicle PIWI-Interacting RNAs Throughout hiPSC-Cardiomyocyte Differentiation

Extracellular Vesicles (EV) play a critical role in the regulation of regenerative processes in wounded tissues by mediating cell-to-cell communication. Multiple RNA species have been identified in EV, although their function still lacks understanding. We previously characterized the miRNA content of EV secreted over hiPSC-cardiomyocyte differentiation and found a distinct miRNA expression in hiPSC-EV driving its in vitro bioactivity. In this work, we investigated the piRNA profiles of EV derived from key stages of the hiPSC-CM differentiation and maturation, i.e., from hiPSC (hiPSC-EV), cardiac progenitors (CPC-EV), immature (CMi-EV), and mature (CMm-EV) cardiomyocytes, demonstrating that EV-piRNA expression differs greatly from the miRNA profiles we previously identified. Only four piRNA were significantly deregulated in EV, one in hiPSC-EV, and three in CPC-EV, as determined by differential expression analysis on small RNA-seq data. Our results provide a valuable source of information for further studies aiming at defining the role of piRNA in the bioactivity and therapeutic potential of EV.

Extracellular Vesicles in Cardiovascular Diseases: Diagnosis and Therapy

Cardiovascular diseases (CVDs) are the leading cause of global mortality. Therapy of CVDs is still a great challenge since many advanced therapies have been developed. Multiple cell types produce nano-sized extracellular vesicles (EVs), including cardiovascular system-related cells and stem cells. Compelling evidence reveals that EVs are associated with the pathophysiological processes of CVDs. Recently researches focus on the clinical transformation in EVs-based diagnosis, prognosis, therapies, and drug delivery systems. In this review, we firstly discuss the current knowledge about the biophysical properties and biological components of EVs. Secondly, we will focus on the functions of EVs on CVDs, and outline the latest advances of EVs as prognostic and diagnostic biomarkers, and therapeutic agents. Finally, we will introduce the specific application of EVs as a novel drug delivery system and its application in CVDs therapy. Specific attention will be paid to summarize the perspectives, challenges, and applications on EVs’ clinical and industrial transformation.

Progress in Bioengineering Strategies for Heart Regenerative Medicine

The human heart has the least regenerative capabilities among tissues and organs, and heart disease continues to be a leading cause of mortality in the industrialized world with insufficient therapeutic options and poor prognosis. Therefore, developing new therapeutic strategies for heart regeneration is a major goal in modern cardiac biology and medicine. Recent advances in stem cell biology and biotechnologies such as human pluripotent stem cells (hPSCs) and cardiac tissue engineering hold great promise for opening novel paths to heart regeneration and repair for heart disease, although these areas are still in their infancy. In this review, we summarize and discuss the recent progress in cardiac tissue engineering strategies, highlighting stem cell engineering and cardiomyocyte maturation, development of novel functional biomaterials and biofabrication tools, and their therapeutic applications involving drug discovery, disease modeling, and regenerative medicine for heart disease.

Schwann cell-derived EVs facilitate dental pulp regeneration through endogenous stem cell recruitment via SDF-1/CXCR4 axis

The dental pulp is critical for physiological vitality of the tooth, and dental pulp regeneration has great potential for rebuilding live pulp tissue after pulp disease. Schwann cells (SCs) play a critical role in the support, maintenance, and regeneration of nerve fibers in dental pulp. Extracellular vesicles (EVs), which possess cell homing and tissue repair potential, derived from SCs (SC-EVs), can regulate dental mesenchymal stem cells (MSCs) proliferation, multipotency, and self-renewal. However, the role of SC-EVs in dental pulp tissue regeneration remains unclear. To address this question, we treated dental pulp stem cells (DPSCs) and bone marrow stem cells (BMSCs) with SC-EVs, and the results showed an obvious increase in the proliferation, migration, and osteogenic differentiation of both cell types. SC-EVs also promoted neurite outgrowth and neuron migration of rat dorsal root ganglia, as well as vessel formation in vitro. In an in vivo model of subcutaneous, SC-EVs enhanced the recruitment of endogenous vascular endothelioid-like cells and MSCs, and promoted the formation of a pulpo-dentinal complex-like structure. Finally, mass spectrometry analyses and western blot revealed that stromal cell-derived factor 1 (SDF-1, also known as CXCL12) plays a dominant role in SC-EVs. Together, these data suggest that SC-EVs successfully recruit endogenous stem cells to promote dental pulp regeneration. Our results provide a cell-free strategy for pulp regeneration that avoids the risks associated with stem cell transplantation. STATEMENT OF SIGNIFICANCE: Dental pulp is vulnerable to infections resulting from dental care, trauma, and multiple restorations, with such infections resulting in pulpitis and pulp necrosis. The current endodontic treatment of irreversible pulp disease cannot restore the function of dental pulp and tissue engineering strategies using cell-based approaches are limited by several disadvantages, including immune rejection and limited cell sources. In this study, we found that schwann cells-derived EVs facilitated dental pulp regeneration through endogenous stem cells recruitment via SDF-1/CXCR4 axis without exogenous cell transplantation. We believe that our study makes a significant contribution to describe a cell-free strategy to promote dental pulp regeneration.

Enhancement strategies for mesenchymal stem cells and related therapies

Cell therapy, particularly mesenchymal stem/stromal (MSC) therapy, has been investigated for a wide variety of disease indications, particularly those with inflammatory pathologies. However, recently it has become evident that the MSC is far from a panacea. In this review we will look at current and future strategies that might overcome limitations in efficacy. Many of these take their inspiration from stem cell niche and the mechanism of MSC action in response to the injury microenvironment, or from previous gene therapy work which can now benefit from the added longevity and targeting ability of a live cell vector. We will also explore the nascent field of extracellular vesicle therapy and how we are already seeing enhancement protocols for this exciting new drug. These enhanced MSCs will lead the way in more difficult to treat diseases and restore potency where donors or manufacturing practicalities lead to diminished MSC effect.

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.

Resuscitating the Field of Cardiac Regeneration: Seeking Answers from Basic Biology

Heart failure (HF) is one of the leading causes for hospital admissions worldwide. HF patients are classified based on the chronic changes in left ventricular ejection fraction (LVEF) as preserved (LVEF ≥ 50%), reduced (LVEF ≤ 40%), or mid-ranged (40% < LVEF < 50%) HFs. Treatments nowadays can prevent HFrEF progress, whereas only a few of the treatments have been proven to be effective in improving the survival of HFpEF. In this review, numerous mediators involved in the pathogenesis of HF are summarized. The regional upstream signaling and their diagnostic and therapeutic potential are also discussed. Additionally, the recent challenges and development in cardiac regenerative therapy that hold opportunities for future research and clinical translation are discussed.

A New Role for Extracellular Vesicles in Cardiac Tissue Engineering and Regenerative Medicine

Cardiovascular diseases are the leading cause of death worldwide. Discovering new therapies to treat heart disease requires improved understanding of cardiac physiology at a cellular level. Extracellular vesicles (EVs) are plasma membrane-bound nano- and microparticles secreted by cells and known to play key roles in intercellular communication, often through transfer of biomolecular cargo. Advances in EV research have established techniques for EV isolation from tissue culture media or biofluids, as well as standards for quantitation and biomolecular characterization. EVs released by cardiac cells are known to be involved in regulating cardiac physiology as well as in the progression of myocardial diseases. Due to difficulty accessing the heart in vivo, advanced in vitro cardiac 'tissues-on-a-chip' have become a recent focus for studying EVs in the heart. These physiologically relevant models are producing new insight into the role of EVs in cardiac physiology and disease while providing a useful platform for screening novel EV-based therapeutics for cardiac tissue regeneration post-injury. Numerous hurdles have stalled the clinical translation of EV therapeutics for heart patients, but tissue-on-a-chip models are playing an important role in bridging the translational gap, improving mechanistic understanding of EV signalling in cardiac physiology, disease, and repair.

Proteomic basis of modulation of postischemic fibrosis by MSC exosomes

After an ischemic event, there is activation of fibroblasts leading to scar formation. It is critical to limit the profibrotic remodeling and activate the reparative remodeling phase to limit cardiac diastolic dysfunction. Mesenchymal stem cell (MSC) exosomes offer significant protection against ischemia-related systolic dysfunction. Here, we studied if MSC exosomes would offer protection against profibrotic events in mouse hearts subjected to acute ischemia [1 h left coronary artery (LCA) occlusion] or chronic ischemia (7 days LCA occlusion). After acute ischemia, there was activation of inflammatory signals, more in the peri-infarct than in the infarct area, in the saline (vehicle)-treated mice. At the same time, there was expression of cardiac remodeling signals (vimentin, collagens-1 and -3, and fibronectin), more in the infarct area. Treatment with MSC exosomes before LCA ligation suppressed inflammatory signals during acute and chronic ischemia. Furthermore, exosome treatment promoted pro-reparative cardiac extracellular matrix (ECM) remodeling in both infarct and peri-infarct areas by suppressing fibronectin secretion and by modulating collagen secretion to reduce fibrotic scar formation through altered cellular signaling pathways. Proteomics study revealed intense expression of IL-1β and activation of profibrotic signals in the saline-treated hearts and their suppression in MSC exosome-treated hearts. To our knowledge, this is the first report on the infarct and peri-infarct area proteomics of ischemic mice hearts to explain MSC exosome-mediated suppression of scar formation in the ischemic mouse hearts.

Amniotic stromal stem cell-loaded hydrogel repairs cardiac tissue in infarcted rat hearts via paracrine mediators

The use of stem cells to repair the heart after a myocardial infarction (MI) remains promising, yet clinical trials over the past 20 years suggest that cells fail to integrate into the native tissue, resulting in limited improvements in cardiac function. Here, we demonstrate the cardioprotective potential of a composite inserting human amniotic stromal mesenchymal stem cells (ASMCs) in a chitosan and hyaluronic acid (C/HA) based hydrogel in a rat MI model. Mechanical characterization of the C/HA platform indicated a swift elastic conversion at 40°C and a rapid sol-gel transition time at 37°C. Cell viability assay presented active and proliferating AMSCs in the C/HA. The ASMCs + C/HA injected composite significantly increased left ventricular ejection fraction, fractional shortening, and neovessel formation. The encapsulated AMSCs were abundantly detected in the infarcted myocardium 6 weeks post-administration and co-expressed cardiac proteins and notably proliferative markers. Proteomic profiling revealed that extracellular vesicles released from hypoxia preconditioned ASMCs contained proteins involved in cytoprotection, angiogenesis, cardiac differentiation and non-canonical Wnt-signaling. Independent activation of non-canonical Wnt-signaling pathways in ASMCs induced cardiogenesis. Despite a low injected cellular density at baseline, the encapsulated AMSCs were abundantly retained and increased cardiac function. Furthermore, the C/HA hydrogel provided an active milieu for the AMSCs to proliferate, co-express cardiac proteins, and induce new vessel formation. Hence, this novel composite of AMSCs + C/HA scaffold is a conceivable candidate that could restore cardiac function and reduce remodeling.

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.

Genetic factors in treatment-related cardiovascular complications in survivors of childhood acute lymphoblastic leukemia

Aim: Cardiovascular disease represents one of the main causes of secondary morbidity and mortality in patients with childhood cancer. Patients & methods: To further address this issue, we analyzed cardiovascular complications in relation to common and rare genetic variants derived through whole-exome sequencing from childhood acute lymphoblastic leukemia survivors (PETALE cohort). Results: Significant associations were detected among common variants in the TTN gene, left ventricular ejection fraction (p ≤ 0.0005), and fractional shortening (p ≤ 0.001). Rare variants enrichment in the NOS1, ABCG2 and NOD2 was observed in relation to left ventricular ejection fraction, and in NOD2 and ZNF267 genes in relation to fractional shortening. Following stratification according to risk groups, the modulatory effect of rare variants was additionally found in the CBR1, ABCC5 and AKR1C3 genes. None of the associations was replicated in St-Jude Lifetime Cohort Study. Conclusion: Further studies are needed to confirm whether the described genetic markers may be useful in identifying patients at increased risk of these complications.

In Vivo Characterization of Endogenous Cardiovascular Extracellular Vesicles in Larval and Adult Zebrafish

Objective

Extracellular vesicles (EVs) facilitate molecular transport across extracellular space, allowing local and systemic signaling during homeostasis and in disease. Extensive studies have described functional roles for EV populations, including during cardiovascular disease, but the in vivo characterization of endogenously produced EVs is still in its infancy. Because of their genetic tractability and live imaging amenability, zebrafish represent an ideal but under-used model to investigate endogenous EVs. We aimed to establish a transgenic zebrafish model to allow the in vivo identification, tracking, and extraction of endogenous EVs produced by different cell types.

Approach and Results

Using a membrane-tethered fluorophore reporter system, we show that EVs can be fluorescently labeled in larval and adult zebrafish and demonstrate that multiple cell types including endothelial cells and cardiomyocytes actively produce EVs in vivo. Cell-type specific EVs can be tracked by high spatiotemporal resolution light-sheet live imaging and modified flow cytometry methods allow these EVs to be further evaluated. Additionally, cryo electron microscopy reveals the full morphological diversity of larval and adult EVs. Importantly, we demonstrate the utility of this model by showing that different cell types exchange EVs in the adult heart and that ischemic injury models dynamically alter EV production.

Conclusions

We describe a powerful in vivo zebrafish model for the investigation of endogenous EVs in all aspects of cardiovascular biology and pathology. A cell membrane fluorophore labeling approach allows cell-type specific tracing of EV origin without bias toward the expression of individual protein markers and will allow detailed future examination of their function.

Stem Cell-Derived Exosomes Potential Therapeutic Roles in Cardiovascular Diseases

Owing to myocardial abnormalities, cardiac ailments are considered to be the major cause of morbidity and mortality worldwide. According to a recent study, membranous vesicles that are produced naturally, termed as "exosomes", have emerged as the potential candidate in the field of cardiac regenerative medicine. A wide spectrum of stem cells has also been investigated in the treatment of cardiovascular diseases (CVD). Exosomes obtained from the stem cells are found to be cardioprotective and offer great hope in the treatment of CVD. The basic nature of exosomes is to deal with the intracellular delivery of both proteins and nucleic acids. This activity of exosomes helps us to rely on them as the attractive pharmaceutical delivery agents. Most importantly, exosomes derived from microRNAs (miRNAs) hold great promise in assessing the risk of CVD, as they serve as notable biomarkers of the disease. Exosomes are small, less immunogenic, and lack toxicity. These nanovesicles harbor immense potential as a therapeutic entity and would provide fruitful benefits if consequential research were focused on their upbringing and development as a useful diagnostic and therapeutic tool in the field of medicine.