Exosomes Derived from TIMP2-Modified Human Umbilical Cord Mesenchymal Stem Cells Enhance the Repair Effect in Rat Model with Myocardial Infarction Possibly by the Akt/Sfrp2 Pathway. Oxid Med Cell Longev. 2019;2019:1958941. [PMID: 31182988 PMCID: PMC6512021 DOI: 10.1155/2019/1958941]

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.

Role of mesenchymal stem cells-derived exosomes on inflammation, apoptosis, fibrosis and telocyte modulation in doxorubicin-induced cardiotoxicity: A closer look at the structural level

Cardiotoxicity induced by doxorubicin (Dox) is a major complication in cancer patients. Exosomes (Ex) derived from mesenchymal cells could be a promising therapeutic for various heart diseases. This study investigated the role of Ex in Dox-induced cardiotoxicity and its mechanistic insights, using Sacubitril/valsartan (S/V) as a reference drug widely recommended in heart failure management. The study involved 24 Wistar rats, divided into a control, Dox, Dox + S/V, and Dox + Ex groups. The rats were assessed for cardiac enzymes, inflammatory and oxidative stress markers. Immunohistochemical expression of caspase-1, nuclear factor erythroid 2-related factor 2 (NrF2), E-Cadherin, CD117/c-kit, and Platelet-derived growth factor-α (PDGFα) was evaluated. P53 and Annexin V were assessed by PCR. Histological examination was performed using hematoxylin and eosin and Sirius red stains. Ex ameliorated the adverse cardiac pathological changes and significantly decreased the cardiac enzymes and inflammatory and oxidative stress markers. Ex also exerted antifibrotic and antiapoptotic effect in heart tissue. Ex treatment also improved NrF2 immunohistochemistry, up-regulated E-Cadherin immune expression, and restored the telocyte markers CD117/c-kit and PDGFα. Ex can mitigate Dox-induced cardiotoxicity by acting as an anti-inflammatory, antioxidant, antiapoptotic, and antifibrotic agents, restoring telocytes and modulating epithelial mesenchymal transition. RESEARCH HIGHLIGHTS: Exosomes exhibit positive expression for CD90 and CD105 whereas showing -ve expression for CD 34 by flow cytometry. Exosomes restore the immunohistochemical expression of the telocytes markers CD117/c-kit and PDGFα. Exosomes alleviate myocardial apoptosis, oxidative stress and fibrosis.

Mesenchymal stem cell-derived exosomes as cell free nanotherapeutics and nanocarriers

Many strategies for regenerating the damaged tissues or degenerating cells are employed in regenerative medicine. Stem cell technology is a modern strategy of the recent approaches, particularly the use of mesenchymal stem cells (MCSs). The ability of MSCs to differentiate as well as their characteristic behaviour as paracrine effector has established them as key elements in tissue repair (Shaer et al., 20141). Recently, extracellular vesicles (EVs) shed by MSCs have emerged as a promising cell free therapy (Citation}Rani, S., Ryan, A. E., Griffin, M. D., and Ritter, T., 20152). This comprehensive review encompasses MSCs-derived exosomes and their therapeutic potential as nanotherapeutics. We also discuss their potency as drug delivery nano-carriers in comparison with liposomes. A better knowledge of EVs behaviour in vivo and of their mechanism of action are key to determine parameters of an optimal formulation in pilot studies and to establish industrial processes.

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

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

Mesenchymal Stem Cell-Derived Exosomes and Their MicroRNAs in Heart Repair and Regeneration

Mesenchymal stem cells (MSCs) can be differentiated into cardiac, endothelial, and smooth muscle cells. Therefore, MSC-based therapeutic approaches have the potential to deal with the aftermaths of cardiac diseases. However, transplanted stem cells rarely survive in damaged myocardium, proposing that paracrine factors other than trans-differentiation may involve in heart regeneration. Apart from cytokines/growth factors, MSCs secret small, single-membrane organelles named exosomes. The MSC-secreted exosomes are enriched in lipids, proteins, nucleic acids, and microRNA (miRNA). There has been an increasing amount of data that confirmed that MSC-derived exosomes and their active molecule microRNA (miRNAs) regulate signaling pathways involved in heart repair/regeneration. In this review, we systematically present an overview of MSCs, their cardiac differentiation, and the role of MSC-derived exosomes and exosomal miRNAs in heart regeneration. In addition, biological functions regulated by MSC-derived exosomes and exosomal-derived miRNAs in the process of heart regeneration are reviewed.

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.

Biomimetic nanomaterials in myocardial infarction treatment: Harnessing bionic strategies for advanced therapeutics

Myocardial infarction (MI) and its associated poor prognosis pose significant risks to human health. Nanomaterials hold great potential for the treatment of MI due to their targeted and controlled release properties, particularly biomimetic nanomaterials. The utilization of biomimetic strategies based on extracellular vesicles (EVs) and cell membranes will serve as the guiding principle for the development of nanomaterial therapy in the future. In this review, we present an overview of research progress on various exosomes derived from mesenchymal stem cells, cardiomyocytes, or induced pluripotent stem cells in the context of myocardial infarction (MI) therapy. These exosomes, utilized as cell-free therapies, have demonstrated the ability to enhance the efficacy of reducing the size of the infarcted area and preventing ischaemic reperfusion through mechanisms such as oxidative stress reduction, polarization modulation, fibrosis inhibition, and angiogenesis promotion. Moreover, EVs can exert cardioprotective effects by encapsulating therapeutic agents and can be engineered to specifically target the infarcted myocardium. Furthermore, we discuss the use of cell membranes derived from erythrocytes, stem cells, immune cells and platelets to encapsulate nanomaterials. This approach allows the nanomaterials to camouflage themselves as endogenous substances targeting the region affected by MI, thereby minimizing toxicity and improving biocompatibility. In conclusion, biomimetic nano-delivery systems hold promise as a potentially beneficial technology for MI treatment. This review serves as a valuable reference for the application of biomimetic nanomaterials in MI therapy and aims to expedite the translation of NPs-based MI therapeutic strategies into practical clinical applications.

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.

Exosomes from preconditioned mesenchymal stem cells: Tissue repair and regeneration

As a prominent research area in tissue repair and regeneration, mesenchymal stem cells (MSCs) have garnered substantial attention for their potential in the treatment of various diseases. It is now widely recognized that the therapeutic effects of MSCs primarily occur through paracrine mechanisms. Among these mechanisms, exosomes play a crucial role by exerting a series of regulatory effects on surrounding cells and tissues. While exosomes have shown promise in treating various diseases, they do have some limitations, such as limited secretion, poor targeting, and single functionality. However, MSC preconditioning can enhance the production of exosomes, lead to more stable functionality and improve therapeutic effects. Moreover, exosomes could also serve as carriers for specific drugs or genes, enabling more precise treatments of diseases. This review summarizes the most recent literatures on how preconditioning of MSCs influences the regenerative potential of their exosomes in tissue repair and provides new insights into the therapeutic application of exosomes derived from MSCs.

Mechanisms and therapeutic strategies of extracellular vesicles in cardiovascular diseases

Cardiovascular disease (CVD) significantly impacts global society since it is the leading cause of death and disability worldwide, and extracellular vesicle (EV)-based therapies have been extensively investigated. EV delivery is involved in mediating the progression of CVDs and has great potential to be biomarker and therapeutic molecular carrier. Besides, EVs from stem cells and cardiac cells can effectively protect the heart from various pathologic conditions, and then serve as an alternative treatment for CVDs. Moreover, the research of using EVs as delivery carriers of therapeutic molecules, membrane engineering modification of EVs, or combining EVs with biomaterials further improves the application potential of EVs in clinical treatment. However, currently there are only a few articles summarizing the application of EVs in CVDs. This review provides an overview of the role of EVs in the pathogenesis and diagnosis of CVDs. It also focuses on how EVs promote the repair of myocardial injury and therapeutic methods of CVDs. In conclusion, it is of great significance to review the research on the application of EVs in the treatment of CVDs, which lays a foundation for further exploration of the role of EVs, and clarifies the prospect of EVs in the treatment of myocardial injury.

Mechanisms and Optimization Strategies of Paracrine Exosomes from Mesenchymal Stem Cells in Ischemic Heart Disease

The morbidity and mortality of myocardial infarction (MI) are increasing worldwide. Mesenchymal stem cells (MSCs) are multipotent stem cells with self-renewal and differentiation capabilities that are essential in tissue healing and regenerative medicine. However, the low implantation and survival rates of transplanted cells hinder the widespread clinical use of stem cells. Exosomes are naturally occurring nanovesicles that are secreted by cells and promote the repair of cardiac function by transporting noncoding RNA and protein. In recent years, MSC-derived exosomes have been promising cell-free treatment tools for improving cardiac function and reversing cardiac remodeling. This review describes the biological properties and therapeutic potential of exosomes and summarizes some engineering approaches for exosomes optimization to enhance the targeting and therapeutic efficacy of exosomes in MI.

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.

Cellular organelles as drug carriers for disease treatment

Organelles not only constitute the basic structure of the cell but also are important in maintaining the normal physiological activities of the cell. With the development of biomimetic nanoscience, researchers have developed technologies to use organelles as drug carriers for disease treatment. Compared with traditional drug carriers, organelle drug carriers have the advantages of good biocompatibility, high drug loading efficiency, and modifiability, and the surface biomarkers of organelles can also participate in intracellular signal transduction to enhance intracellular and intercellular communication, and assist in enhancing the therapeutic effect of drugs. Among different types of organelles, extracellular vesicles, lipid droplets, lysosomes, and mitochondria have been used as drug carriers. This review briefly reviews the biogenesis, isolation methods, and drug-loading methods of four types of organelles, and systematically summarizes the research progress in using organelles as drug-delivery systems for disease treatment. Finally, the challenges faced by organelle-based drug delivery systems are discussed. Although the organelle-based drug delivery systems still face challenges before they can achieve clinical translation, they offer a new direction and vision for the development of next-generation drug carriers.

Exosomes as cutting-edge therapeutics in various biomedical applications: An update on engineering, delivery, and preclinical studies

Exosomes are cell-derived nanovesicles, circulating in different body fluids, and acting as an intercellular mechanism. They can be purified from culture media of different cell types and carry an enriched content of various protein and nucleic acid molecules originating from their parental cells. It was indicated that the exosomal cargo can mediate immune responses via many signaling pathways. Over recent years, the therapeutic effects of various exosome types were broadly investigated in many preclinical studies. Herein, we present an update on recent preclinical studies on exosomes as therapeutic and/or delivery agents for various applications. The exosome origin, structural modifications, natural or loaded active ingredients, size, and research outcomes were summarized for various diseases. Overall, the present article provides an overview of the latest exosome research interests and developments to clear the way for the clinical study design and application.

Dual human iPSC-derived cardiac lineage cell-seeding extracellular matrix patches promote regeneration and long-term repair of infarcted hearts

Human pluripotent stem cell-derived cardiovascular progenitor cells (hCVPCs) and cardiomyocytes (hCMs) possess therapeutic potential for infarcted hearts; however, their efficacy needs to be enhanced. Here we tested the hypotheses that the combination of decellularized porcine small intestinal submucosal extracellular matrix (SIS-ECM) with hCVPCs, hCMs, or dual of them (Mix, 1:1) could provide better therapeutic effects than the SIS alone, and dual hCVPCs with hCMs would exert synergic effects in cardiac repair. The data showed that the SIS patch well supported the growth of hCVPCs and hCMs. Epicardially implanted SIS-hCVPC, SIS-hCM, or SIS-Mix patches at 7-day post-myocardial infarction significantly ameliorated functional worsening, ventricular dilation and scar formation at 28- and 90-day post-implantation in C57/B6 mice, whereas the SIS only mildly improved function at 90-day post-implantation. Moreover, the SIS and SIS-cell patches improved vascularization and suppressed MI-induced cardiomyocyte hypertrophy and expression of Col1 and Col3, but only the SIS-hCM and the SIS-Mix patches increased the ratio of collagen III/I fibers in the infarcted hearts. Further, the SIS-cell patches stimulated cardiomyocyte proliferation via paracrine action. Notably, the SIS-Mix had better improvements in cardiac function and structure, engraftments, and cardiomyocyte proliferation. Proteomic analysis showed distinct biological functions of exclusive proteins secreted from hCVPCs and hCMs, and more exclusive proteins secreted from co-cultivated hCVPCs and hCMs than mono-cells involving in various functional processes essential for infarct repair. These findings are the first to demonstrate the efficacy and mechanisms of mono- and dual-hCVPC- and hCM-seeding SIS-ECM for repair of infarcted hearts based on the side-by-side comparison.

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

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

Clinical utility of mesenchymal stem/stromal cells in regenerative medicine and cellular therapy

Mesenchymal stem/stromal cells (MSCs) have been carefully examined to have tremendous potential in regenerative medicine. With their immunomodulatory and regenerative properties, MSCs have numerous applications within the clinical sector. MSCs have the properties of multilineage differentiation, paracrine signaling, and can be isolated from various tissues, which makes them a key candidate for applications in numerous organ systems. To accentuate the importance of MSC therapy for a range of clinical indications, this review highlights MSC-specific studies on the musculoskeletal, nervous, cardiovascular, and immune systems where most trials are reported. Furthermore, an updated list of the different types of MSCs used in clinical trials, as well as the key characteristics of each type of MSCs are included. Many of the studies mentioned revolve around the properties of MSC, such as exosome usage and MSC co-cultures with other cell types. It is worth noting that MSC clinical usage is not limited to these four systems, and MSCs continue to be tested to repair, regenerate, or modulate other diseased or injured organ systems. This review provides an updated compilation of MSCs in clinical trials that paves the way for improvement in the field of MSC therapy.

Potential of Mesenchymal Stromal Cell-Derived Extracellular Vesicles as Natural Nanocarriers: Concise Review

Intercellular communication, through direct and indirect cell contact, is mandatory in multicellular organisms. These last years, the microenvironment, and in particular, transfer by extracellular vesicles (EVs), has emerged as a new communication mechanism. Different biological fluids and cell types are common sources of EVs. EVs play different roles, acting as signalosomes, biomarkers, and therapeutic agents. As therapeutic agents, MSC-derived EVs display numerous advantages: they are biocompatible, non-immunogenic, and stable in circulation, and they are able to cross biological barriers. Furthermore, EVs have a great potential for drug delivery. Different EV isolation protocols and loading methods have been tested and compared. Published and ongoing clinical trials, and numerous preclinical studies indicate that EVs are safe and well tolerated. Moreover, the latest studies suggest their applications as nanocarriers. The current review will describe the potential for MSC-derived EVs as drug delivery systems (DDS) in disease treatment, and their advantages. Thereafter, we will outline the different EV isolation methods and loading techniques, and analyze relevant preclinical studies. Finally, we will describe ongoing and published clinical studies. These elements will outline the benefits of MSC-derived EV DDS over several aspects.

Mechanisms behind therapeutic potentials of mesenchymal stem cell mitochondria transfer/delivery

Mesenchymal stromal/stem cells (MSCs) perform their therapeutic effects through various mechanisms, including their ability to differentiate, producing different growth factors, immunomodulatory factors, and extracellular vesicles (EVs). In addition to the mentioned mechanisms, a new aspect of the therapeutic potential of MSCs has recently been noticed, which occurs through mitochondrial transfer. Various methods of MSCs mitochondria transfer have been used in studies to benefit from their therapeutic potential. Among these methods, mitochondrial transfer after MSCs transplantation in cell-to-cell contact, EVs-mediated transfer of mitochondria, and the use of MSCs isolated mitochondria (MSCs-mt) are well studied. Pathological conditions can affect the cells in the damaged microenvironment and lead to cells mitochondrial damage. Since the defect in the mitochondrial function of the cell leads to a decrease in ATP production and the subsequent cell death, restoring the mitochondrial content, functions, and hemostasis can affect the functions of the damaged cell. Various studies show that the transfer of MSCs mitochondria to other cells can affect vital processes such as proliferation, differentiation, cell metabolism, inflammatory responses, cell senescence, cell stress, and cell migration. These changes in cell attributes and behavior are very important for therapeutic purposes. For this reason, their investigation can play a significant role in the direction of the researchers'.

Mesenchymal Stem Cells and Their Exocytotic Vesicles

Mesenchymal stem cells (MSCs), as a kind of pluripotent stem cells, have attracted much attention in orthopedic diseases, geriatric diseases, metabolic diseases, and sports functions due to their osteogenic potential, chondrogenic differentiation ability, and adipocyte differentiation. Anti-inflammation, anti-fibrosis, angiogenesis promotion, neurogenesis, immune regulation, and secreted growth factors, proteases, hormones, cytokines, and chemokines of MSCs have been widely studied in liver and kidney diseases, cardiovascular and cerebrovascular diseases. In recent years, many studies have shown that the extracellular vesicles of MSCs have similar functions to MSCs transplantation in all the above aspects. Here we review the research progress of MSCs and their exocrine vesicles in recent years.

Human Umbilical Cord Mesenchymal Stem Cells Attenuate Severe Burn-Induced Multiple Organ Injury via Potentiating IGF-1 and BCL-2/BAX Pathway

Background

Early multiple organ injuries induced by severe burn predict a high mortality. Mesenchymal stem cells (MSCs) are able to repair and reconstruct the injured tissues and organs induced by trauma and diseases. However, potential protective effect and mechanism of MSCs on multiorgan injury induced by severe burn at early stage remain to be not clarified. Therefore, this study was to explore the effect and mechanism of human umbilical cord-derived MSCs (hUCMSCs) against severe burn-induced early organ injuries in rats.

Methods

Adult male Wistar rats were randomly divided into sham, burn, and burn+hUCMSCsgroups. GFP-labeled hUCMSCs or PBS was intravenous injected into respective groups. Migration and distribution patterns of GFP-labeled hUCMSCs were observed by inverted fluorescence microscope. The structures and cell apoptosis of the heart, kidney, and liver were measured by immunohistochemistry. Biochemical parameters in serum were assayed by standard Roche-Hitachi methodology. Western blotting was performed on these organs of rats in the three groups to explore the underlying mechanisms.

Results

At 24 hours after hUCMSCs transplantation, we found that GFP-labeled hUCMSCs mainly localized in the blood vessel of the heart, kidney, and liver and a very few cells migrated into tissues of these organs. Compared with the sham group, structure damages and cell apoptosis of these organs were induced by severe burn, and systematic administrations of hUCMSCs significantly improved the damaged structures, cell apoptosis rates, and biochemical parameters of these organs. Furthermore, IGF-1 (insulin-like growth factor 1) level in burn+hUCMSCs group was significantly higher than that in the sham and burn groups. Meanwhile, severe burn induced BCL-2/BAX significantly decreased compared to the sham group, and it was markedly increased by hUCMSCs administration.

Conclusion

The hUCMSCs transplantation can attenuate severe burn-induced early organ injuries and protect multiorgan functions by encouraging migration of hUCMSCs with blood circulation and increasing protective cytokine IGF-1 level and regulating BCL-2/BAX pathway of these vital organs. Furthermore, these data might provide the theoretical foundation for further clinical applications of hUCMSCs in burn areas.

Exosomes as a Cell-free Therapy for Myocardial Injury Following Acute Myocardial Infarction or Ischemic Reperfusion

Exosomes, which contain miRNA, have been receiving growing attention in cardiovascular therapy because of their role in mediating cell-cell communication, autophagy, apoptosis, inflammation, and angiogenesis. Several studies have suggested that miRNA derived from exosomes can be used to detect myocardial infarctions (MI) in patients. Basic research also suggests that exosomes could serve as a potential therapeutic target for treating acute myocardial infarction. Ischemia/reperfusion (IR) injury is associated with adverse cardiac events after acute MI. We aim to review the potential benefits and mechanisms of exosomes in treating MI and IR injury.

Proteomics profile of mesenchymal stromal cells and extracellular vesicles in normoxic and hypoxic conditions

BACKGROUND AIMS

Although bone marrow-derived mesenchymal stromal cells (MSCs) have demonstrated success in pre-clinical studies, they have shown only mild therapeutic effects in clinical trials. Hypoxia pre-conditioning may optimize the performance of bone marrow-derived MSCs because it better reflects the physiological conditions of their origin. It is not known whether changes in the protein profile caused by hypoxia in MSCs can be extended to the extracellular vesicles (EVs) released from them. The aim of this study was to evaluate the proteomics profile of MSCs and their EVs under normoxic and hypoxic conditions.

METHODS

Bone marrow-derived MSCs were isolated from six healthy male Wistar rats. After achieving 80% confluence, MSCs were subjected to normoxia (MSC-Norm) (21% oxygen, 5% carbon dioxide, 74% nitrogen) or hypoxia (MSC-Hyp) (1% oxygen, 5% carbon dioxide, 94% nitrogen) for 48 h. Cell viability and oxygen consumption rate were assessed. EVs were extracted from MSCs for each condition (EV-Norm and EV-Hyp) by ultracentrifugation. Total proteins were isolated from MSCs and EVs and prepared for mass spectrometry. EVs were characterized by nanoparticle tracking analysis. Proteomics data were analyzed by PatternLab 4.0, Search Tool for the Retrieval of Interacting Genes/Proteins, Gene Ontology, MetaboAnalyst and Reactome software.

RESULTS

Cell viability was higher in MSC-Hyp than MSC-Norm (P = 0.007). Basal respiration (P = 0.001), proton leak (P = 0.004) and maximal respiration (P = 0.014) were lower in MSC-Hyp than MSC-Norm, and no changes in adenosine triphosphate-linked and residual respiration were observed. The authors detected 2177 proteins in MSC-Hyp and MSC-Norm, of which 147 were identified in only MSC-Hyp and 512 were identified in only MSC-Norm. Furthermore, 718 proteins were identified in EV-Hyp and EV-Norm, of which 293 were detected in only EV-Hyp and 30 were detected in only EV-Norm. Both MSC-Hyp and EV-Hyp showed enrichment of pathways and biological processes related to glycolysis, the immune system and extracellular matrix organization.

CONCLUSIONS

MSCs subjected to hypoxia showed changes in their survival and metabolic activity. In addition, MSCs under hypoxia released more EVs, and their content was related to expression of regulatory proteins of the immune system and extracellular matrix organization. Because of the upregulation of proteins involved in glycolysis, gluconeogenesis and glucose uptake during hypoxia, production of reactive oxygen species and expression of immunosuppressive properties may be affected.

Extracellular Vesicles: A New Frontier for Cardiac Repair

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

Tailored Extracellular Vesicles: Novel Tool for Tissue Regeneration

Extracellular vesicles (EVs) play an essential part in multiple pathophysiological processes including tissue injury and regeneration because of their inherent characteristics of small size, low immunogenicity and toxicity, and capability of carrying a variety of bioactive molecules and mediating intercellular communication. Nevertheless, accumulating studies have shown that the application of EVs faces many challenges such as insufficient therapeutic efficacy, a lack of targeting capability, low yield, and rapid clearance from the body. It is known that EVs can be engineered, modified, and designed to encapsulate therapeutic cargos like proteins, peptides, nucleic acids, and drugs to improve their therapeutic efficacy. Targeted peptides, antibodies, aptamers, magnetic nanoparticles, and proteins are introduced to modify various cell-derived EVs for increasing targeting ability. In addition, extracellular vesicle mimetics (EMs) and self-assembly EV-mimicking nanocomplex are applied to improve production and simplify EV purification process. The combination of EVs with biomaterials like hydrogel, and scaffolds dressing endows EVs with long-term therapeutic efficacy and synergistically enhanced regenerative outcome. Thus, we will summarize recent developments of EV modification strategies for more extraordinary regenerative effect in various tissue injury repair. Subsequently, opportunities and challenges of promoting the clinical application of engineered EVs will be discussed.

Rab27a-dependent exosomes protect against cerebral ischemic injury by reducing endothelial oxidative stress and apoptosis

Introduction

Multicellular crosstalk within the brain tissue has been suggested to play a critical role in maintaining cerebral vascular homeostasis. Exosomes (EXs) mediated cell–cell communication, but its role in cerebral ischemic injury is largely unknown. Rab27a is one of the major genes controlling EX release. Here, we explored the role of Rab27a in regulating brain EXs secretion, and the effects of Rab27a‐mediated EXs on ischemia evoked cerebral vascular disruption and brain injury.

Methods

Cerebral ischemia was induced in Rab27a knockout (Rab27a^−/−) and wide type (WT) mice by transient middle cerebral artery occlusion (tMCAO). Differential gene expression analysis was performed in ischemic brain tissue by using mRNA sequencing. EXs isolated from brain tissue of Rab27a^−/− and WT mice (EX^WT or EX^{Rab27a−/−}) were pre‐administrated into tMCAO operated Rab27a^−/− mice or oxygen and glucose deprivation (OGD) treated primary brain vascular endothelial cells (ECs).

Results

We demonstrated that Rab27a expression in the peri‐infarct area of brain was significantly elevated, which was associated with local elevation in EXs secretion. Rab27a deficiency dramatically decreased the level of EXs in brain tissue of normal and tMCAO‐treated mice, and Rab27a^−/− mice displayed an increase in infarct volume and NDS, and a decrease in cMVD and CBF following tMCAO. Pre‐infusion of EX^WT increased the brain EXs levels in the tMCAO operated Rab27a^−/− mice, accompanied with an increase in cMVD and CBF, and a decrease in infarct volume, NDS, ROS production, and apoptosis. The effects of EX^{Rab27a−/−} infusion were much diminished although in a dose‐dependent manner. In OGD‐treated ECs, EX^{Rab27a−/−} showed less effectivity than EX^WT in decreasing ROS overproduction and apoptosis, paralleling with down‐regulated expression of NOX2 and cleaved caspase‐3.

Conclusion

Our study demonstrates that Rab27a controls brain EXs secretion and functions, contributing to cerebral vascular protection from ischemic insult by preventing oxidative stress and apoptosis via down‐regulating NOX2 and cleaved caspase‐3 expression.

Mesenchymal Stem Cell Mechanisms of Action and Clinical Effects in Osteoarthritis: A Narrative Review

With the insufficient satisfaction rates and high cost of operative treatment for osteoarthritis (OA), alternatives have been sought. Furthermore, the inability of current medications to arrest disease progression has led to rapidly growing clinical research relating to mesenchymal stem cells (MSCs). The availability and function of MSCs vary according to tissue source. The three primary sources include the placenta, bone marrow, and adipose tissue, all of which offer excellent safety profiles. The primary mechanisms of action are trophic and immunomodulatory effects, which prevent the further degradation of joints. However, the function and degree to which benefits are observed vary significantly based on the exosomes secreted by MSCs. Paracrine and autocrine mechanisms prevent cell apoptosis and tissue fibrosis, initiate angiogenesis, and stimulate mitosis via growth factors. MSCs have even been shown to exhibit antimicrobial effects. Clinical results incorporating clinical scores and objective radiological imaging have been promising, but a lack of standardization in isolating MSCs prevents their incorporation in current guidelines.

Insight in Hypoxia-Mimetic Agents as Potential Tools for Mesenchymal Stem Cell Priming in Regenerative Medicine

Hypoxia-mimetic agents are new potential tools in MSC priming instead of hypoxia incubators or chambers. Several pharmaceutical/chemical hypoxia-mimetic agents can be used to induce hypoxia in the tissues: deferoxamine (DFO), dimethyloxaloylglycine (DMOG), 2,4-dinitrophenol (DNP), cobalt chloride (CoCl2), and isoflurane (ISO). Hypoxia-mimetic agents can increase cell proliferation, preserve or enhance differentiation potential, increase migration potential, and induce neovascularization in a concentration- and stem cell source-dependent manner. Moreover, hypoxia-mimetic agents may increase HIF-1α, changing the metabolism and enhancing glycolysis like hypoxia. So, there is clear evidence that treatment with hypoxia-mimetic agents is beneficial in regenerative medicine, preserving stem cell capacities. These agents are not studied so wildly as hypoxia but, considering the low cost and ease of use, are believed to find application as pretreatment of many diseases such as ischemic heart disease and myocardial fibrosis and promote cardiac and cartilage regeneration. The knowledge of MSC priming is critical in evaluating safety procedures and use in clinics. In this review, similarities and differences between hypoxia and hypoxia-mimetic agents in terms of their therapeutic efficiency are considered in detail. The advantages, challenges, and future perspectives in MSC priming with hypoxia mimetic agents are also discussed.

Emerging Trends in Mesenchymal Stem Cells Applications for Cardiac Regenerative Therapy: Current Status and Advances

Irreversible myocardium infarction is one of the leading causes of cardiovascular disease (CVD) related death and its quantum is expected to grow in coming years. Pharmacological intervention has been at the forefront to ameliorate injury-related morbidity and mortality. However, its outcomes are highly skewed. As an alternative, stem cell-based tissue engineering/regenerative medicine has been explored quite extensively to regenerate the damaged myocardium. The therapeutic modality that has been most widely studied both preclinically and clinically is based on adult multipotent mesenchymal stem cells (MSC) delivered to the injured heart. However, there is debate over the mechanistic therapeutic role of MSC in generating functional beating cardiomyocytes. This review intends to emphasize the role and use of MSC in cardiac regenerative therapy (CRT). We have elucidated in detail, the various aspects related to the history and progress of MSC use in cardiac tissue engineering and its multiple strategies to drive cardiomyogenesis. We have further discussed with a focus on the various therapeutic mechanism uncovered in recent times that has a significant role in ameliorating heart-related problems. We reviewed recent and advanced technologies using MSC to develop/create tissue construct for use in cardiac regenerative therapy. Finally, we have provided the latest update on the usage of MSC in clinical trials and discussed the outcome of such studies in realizing the full potential of MSC use in clinical management of cardiac injury as a cellular therapy module.

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.

Validated Impacts of N6-Methyladenosine Methylated mRNAs on Apoptosis and Angiogenesis in Myocardial Infarction Based on MeRIP-Seq Analysis

Objectives: N6-methyladenosine (m⁶A) is hypothesized to play a role in the regulation of pathogenesis of myocardial infarction (MI). This study was designed to compare m⁶A-tagged transcript profiles to identify mRNA-specific changes on pathophysiological variations after MI.

Methods: N6-methyladenosine methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) were interacted to select m⁶A-modified mRNAs with samples collected from sham operated and MI rat models. m⁶A methylation regulated mRNAs were interacted with apoptosis/angiogenesis related genes in GeneCards. Afterwards, MeRIP-quantitative real-time PCR (MeRIP-qRT-PCR) was performed to measure m⁶A methylation level of hub mRNAs. m⁶A methylation variation was tested under different oxygen concentration or hypoxic duration in H9c2 cells and HUVECs. In addition, Western blot and qRT-PCR were employed to detect expression of hub mRNAs and relevant protein level. Flow cytometry and Tunel assay were conducted to assess apoptotic level. CCK-8, EdU, and tube formation assay were performed to measure cell proliferation and tube formation ability.

Results: Upregulation of Mettl3 was firstly observed in vivo and in vitro, followed by upregulation of m⁶A methylation level. A total of 567 significantly changed m⁶A methylation peaks were identified, including 276 upregulated and 291 downregulated peaks. A total of 576 mRNAs were upregulated and 78 were downregulated. According to combined analysis of MeRIP-seq and RNA-seq, we identified 26 significantly hypermethylated and downregulated mRNAs. Based on qRT-PCR and interactive analysis, Hadh, Kcnn1, and Tet1 were preliminarily identified as hub mRNAs associated with apoptosis/angiogenesis. MeRIP-qRT-PCR assay confirmed the results from MeRIP-seq. With the inhibition of Mettl3 in H9c2 cells and HUVECs, downregulated m⁶A methylation level of total RNA and upregulated expression of hub mRNAs were observed. Increased m⁶A level was verified in the gradient context in terms of prolonged hypoxic duration and decreased oxygen concentration. Under simulated hypoxia, roles of Kcnn1 and Tet1 in angiogenesis and Hadh, Tet1, and Kcnn1 in apoptosis were further confirmed with our validation experiments.

Conclusion: Roles of m⁶A-modified mRNA transcripts in the context of MI were preliminarily verified. In the context of m⁶A methylation, three hub mRNAs were validated to impact the process of apoptosis/angiogenesis. Our study provided theoretical basis and innovative targets for treatment of MI and paved the way for future investigations aiming at exploring upstream epigenetic mechanisms of pathogenesis after MI.

Therapeutic Applications of Extracellular Vesicles for Myocardial Repair

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

Targeting angiogenesis in myocardial infarction: Novel therapeutics (Review)

Acute myocardial infarction (AMI) remains the main cause of mortality worldwide. Despite surgery and medical treatment, the non-regeneration of dead cardiomyocytes and the limited contractile ability of scar tissue can lead to heart failure. Therefore, restoring blood flow in the infarcted area is important for the repair of myocardial injury. The objective of the present review was to summarize the factors influencing angiogenesis after AMI, and to describe the application of angiogenesis for cardiac repair. Collectively, this review may be helpful for relevant studies and to provide insight into future therapeutic applications in clinical practice.

SFRP2 Improves Mitochondrial Dynamics and Mitochondrial Biogenesis, Oxidative Stress, and Apoptosis in Diabetic Cardiomyopathy

Background

The mitochondrial dynamics and mitochondrial biogenesis are essential for maintaining the bioenergy function of mitochondria in diabetic cardiomyopathy (DCM). Previous studies have revealed that secreted frizzled-related protein 2 (SFRP2) is beneficial against apoptosis and oxidative stress. However, no research has confirmed whether SFRP2 regulates oxidative stress and apoptosis through mitochondrial function in DCM.

Methods

Exposure of H9C2 cardiomyocytes in high glucose (HG) 25 mM and palmitic acid (PAL) 0.2 mM was used to simulate DCM in vitro. H9C2 cells with SFRP2 overexpression or SFRP2 knockdown were constructed and cultured under glucolipotoxicity or normal glucose conditions. An SD rat model of type 2 diabetes mellitus (T2DM) was generated using a high-fat diet combined with a low-dose STZ injection. Overexpression of SFRP2 in the rat model was generated by using an adeno-associated virus approach. CCK-8, TUNEL assay, and DHE staining were used to detect cell viability, and MitoTracker Red CMXRos was used to detect changes in mitochondrial membrane potential. We used qRT-PCR and western blot to further explore the mechanisms of SFRP2 regulating mitochondrial dynamics through the AMPK/PGC1-α pathway to improve diabetic cardiomyocyte injury.

Results

Our results indicated that SFRP2 was significantly downregulated in H9C2 cells and cardiac tissues in T2DM conditions, accompanied by decreased expression of mitochondrial dysfunction. The mitochondrial membrane potential was reduced, and the cells were led to oxidative stress injury and apoptosis. Furthermore, the overexpression of SFRP2 could reverse apoptosis and promote mitochondrial function in T2DM conditions in vitro and in vivo. We also found that silencing endogenous SFRP2 could further promote glucolipotoxicity-induced mitochondrial dysfunction and apoptosis in cardiomyocytes, accompanied by downregulation of p-AMPK.

Conclusion

SFRP2 exerted cardioprotective effects by salvaging mitochondrial function in an AMPK-PGC1-α-dependent manner, which modulates mitochondrial dynamics and mitochondrial biogenesis, reducing oxidative stress and apoptosis. SFRP2 may be a promising therapeutic biomarker in DCM.

Modulation of Cardiac Fibrosis in and Beyond Cells

The extracellular matrix (ECM) plays important roles in maintaining physiological structure and functions of various tissues and organs. Cardiac fibrosis is the excess deposition of ECM, including both fibrillar (collagens I and III) and non-fibrillar proteins. Characteristics of fibrosis can vary depending on the pathology, with focal fibrosis occurring following myocardial infarction (MI), and diffuse interstitial and perivascular fibrosis mainly in non-ischemic heart diseases. Compliance of the fibrotic tissue is significantly lower than the normal myocardium, and this can compromise the diastolic, as well as systolic dysfunction. Therefore, strategies to combat cardiac fibrosis have been investigated. Upon injury or inflammation, activated cardiac fibroblasts (myofibroblasts) produce more ECM proteins and cause fibrosis. The activation could be inhibited or the myofibroblasts could be ablated by targeting their specific expressed proteins. Modulation of tissue inhibitors of metalloproteinases (TIMPs) and moderate exercise can also suppress cardiac fibrosis. More recently, sex differences in cardiac fibrosis have come to light with differential fibrotic response in heart diseases as well as in fibroblast functions in vitro. This mini-review discusses recent progress in cardiac fibroblasts, TIMPs, sex differences and exercise in modulation of cardiac fibrosis.

Extracellular vesicles in cardiovascular disease: Biological functions and therapeutic implications

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

Extracellular Vesicles Derived From Human Umbilical Cord Mesenchymal Stem Cells Protect Against DOX-Induced Heart Failure Through the miR-100-5p/NOX4 Pathway

The end result of a variety of cardiovascular diseases is heart failure. Heart failure patients’ morbidity and mortality rates are increasing year after year. Extracellular vesicles (EVs) derived from human umbilical cord mesenchymal stem cells (HucMSC-EVs) have recently been discovered to be an alternative treatment for heart failure, according to recent research. In this study, we aimed to explore the underlying mechanisms in which HucMSC-EVs inhibited doxorubicin (DOX)-induced heart failure in AC16 cells. An miR-100-5p inhibitor and an miR-100-5p mimic were used to transfect HucMSCs using Lipofectamine 2000. HucMSC-EVs were isolated and purified using the ultracentrifugation method. AC16 cells were treated with DOX combined with HucMSC-EVs or an EV miR-100-5-p inhibitor or EV miR-100-5-p mimic. ROS levels were measured by a flow cytometer. The levels of LDH, SOD, and MDA were measured by biochemical methods. Apoptotic cells were assessed by a flow cytometer. Cleaved-caspase-3 and NOX4 protein expression were determined by Western blot. The experiment results showed that HucMSC-EVs inhibited DOX-induced increased levels of ROS, LDH, and MDA, and decreased levels of SOD which were reversed by an EV miR-100-5-p inhibitor, while EV miR-100-5-p mimic had a similar effect to HucMSC-EVs. At the same time, HucMSC-EV-inhibited DOX induced the increases of apoptotic cells as well as NOX4 and cleaved-caspase-3 protein expression, which were reversed by an EV miR-100-5-p inhibitor. Furthermore, the NOX4 expression was negatively regulated by miR-100-5p. Overexpression of NOX4 abolished the effects in which HucMSC-EVs inhibited DOX-induced ROS, oxidative stress, and apoptosis increases. In conclusion, these results indicate that HucMSC-EVs inhibit DOX-induced heart failure through the miR-100-5p/NOX4 pathway.

Advances in Nanomaterials for Injured Heart Repair

Atherosclerotic cardiovascular disease (ASCVD) is one of the leading causes of mortality worldwide. Because of the limited regenerative capacity of adult myocardium to compensate for the loss of heart tissue after ischemic infarction, scientists have been exploring the possible mechanisms involved in the pathological process of ASCVD and searching for alternative means to regenerate infarcted cardiac tissue. Although numerous studies have pursued innovative solutions for reversing the pathological process of ASCVD and improving the effectiveness of delivering therapeutics, the translation of those advances into downstream clinical applications remains unsatisfactory because of poor safety and low efficacy. Recently, nanomaterials (NMs) have emerged as a promising new strategy to strengthen both the efficacy and safety of ASCVD therapy. Thus, a comprehensive review of NMs used in ASCVD treatment will be useful. This paper presents an overview of the pathophysiological mechanisms of ASCVD and the multifunctional mechanisms of NM-based therapy, including antioxidative, anti-inflammation and antiapoptosis mechanisms. The technological improvements of NM delivery are summarized and the clinical transformations concerning the use of NMs to treat ASCVD are examined. Finally, this paper discusses the challenges and future perspectives of NMs in cardiac regeneration to provide insightful information for health professionals on the latest advancements in nanotechnologies for ASCVD treatment.

Comparing the Therapeutic Potential of Stem Cells and their Secretory Products in Regenerative Medicine

Cell therapy involves the transplantation of human cells to replace or repair the damaged tissues and modulate the mechanisms underlying disease initiation and progression in the body. Nowadays, many different types of cell-based therapy are developed and used to treat a variety of diseases. In the past decade, cell-free therapy has emerged as a novel approach in regenerative medicine after the discovery that the transplanted cells exerted their therapeutic effect mainly through the secretion of paracrine factors. More and more evidence showed that stem cell-derived secretome, i.e., growth factors, cytokines, and extracellular vesicles, can repair the injured tissues as effectively as the cells. This finding has spurred a new idea to employ secretome in regenerative medicine. Despite that, will cell-free therapy slowly replace cell therapy in the future? Or are these two modes of treatment still needed to address different diseases and conditions? This review provides an indepth discussion about the values of stem cells and secretome in regenerative medicine. In addition, the safety, efficacy, advantages, and disadvantages of using these two modes of treatment in regenerative medicine are also critically reviewed.

Small extracellular vesicles from menstrual blood-derived mesenchymal stem cells (MenSCs) as a novel therapeutic impetus in regenerative medicine

Menstrual blood-derived mesenchymal stem cells (MenSCs) have great potential in regenerative medicine. MenSC has received increasing attention owing to its impressive therapeutic effects in both preclinical and clinical trials. However, the study of MenSC-derived small extracellular vesicles (EVs) is still in its initial stages, in contrast to some common MSC sources (e.g., bone marrow, umbilical cord, and adipose tissue). We describe the basic characteristics and biological functions of MenSC-derived small EVs. We also demonstrate the therapeutic potential of small EVs in fulminant hepatic failure, myocardial infarction, pulmonary fibrosis, prostate cancer, cutaneous wound, type-1 diabetes mellitus, aged fertility, and potential diseases. Subsequently, novel hotspots with respect to MenSC EV-based therapy are proposed to overcome current challenges. While complexities regarding the therapeutic potential of MenSC EVs continue to be unraveled, advances are rapidly emerging in both basic science and clinical medicine. MenSC EV-based treatment has great potential for treating a series of diseases as a novel therapeutic strategy in regenerative medicine.

Extracellular vesicles as a drug delivery system: A systematic review of preclinical studies

During the past decades, extracellular vesicles (EVs) have emerged as an attractive drug delivery system. Here, we assess their pre-clinical applications, in the form of a systematic review. For each study published in the past decade, disease models, animal species, EV donor cell types, active pharmaceutical ingredients (APIs), EV surface modifications, API loading methods, EV size and charge, estimation of EV purity, presence of biodistribution studies and administration routes were quantitatively analyzed in a defined and reproducible way. We have interpreted the trends we observe over the past decade, to define the niches where to apply EVs for drug delivery in the future and to provide a basis for regulatory guidelines.

Mesenchymal stromal cell-derived exosomes in cardiac regeneration and repair

Mesenchymal stromal cell (MSC)-derived exosomes play a promising role in regenerative medicine. Their trophic and immunomodulatory potential has made them a promising candidate for cardiac regeneration and repair. Numerous studies have demonstrated that MSC-derived exosomes can replicate the anti-inflammatory, anti-apoptotic, and pro-angiogenic and anti-fibrotic effects of their parent cells and are considered a substitute for cell-based therapies. In addition, their lower tumorigenic risk, superior immune tolerance, and superior stability compared with their parent stem cells make them an attractive option in regenerative medicine. The therapeutic effects of MSC-derived exosomes have consequently been evaluated for application in cardiac regeneration and repair. In this review, we summarize the potential mechanisms and therapeutic effects of MSC-derived exosomes in cardiac regeneration and repair and provide evidence to support their clinical application.

Cell Death and Exosomes Regulation After Myocardial Infarction and Ischemia-Reperfusion

Cardiovascular disease (CVD) is the leading cause of death in the global population, accounting for about one-third of all deaths each year. Notably, with CVDs, myocardial damages result from myocardial infarction (MI) or cardiac arrhythmias caused by interrupted blood flow. Significantly, in the process of MI or myocardial ischemic-reperfusion (I/R) injury, both regulated and non-regulated cell death methods are involved. The critical factor for patients’ prognosis is the infarct area’s size, which determines the myocardial cells’ survival. Cell therapy for MI has been a research hotspot in recent years; however, exosomes secreted by cells have attracted much attention following shortcomings concerning immunogens. Exosomes are extracellular vesicles containing several biologically active substances such as lipids, nucleic acids, and proteins. New evidence suggests that exosomes play a crucial role in regulating cell death after MI as exosomes of various stem cells can participate in the cell damage process after MI. Hence, in the review herein, we focused on introducing various cell-derived exosomes to reduce cell death after MI by regulating the cell death pathway to understand myocardial repair mechanisms better and provide a reference for clinical treatment.

The Application Potential and Advance of Mesenchymal Stem Cell-Derived Exosomes in Myocardial Infarction

Myocardial infarction (MI) is a devastating disease with high morbidity and mortality caused by the irreversible loss of functional cardiomyocytes and heart failure (HF) due to the restricted blood supply. Mesenchymal stem cells (MSCs) have been emerging as lead candidates to treat MI and subsequent HF mainly through secreting multitudinous factors of which exosomes act as the most effective constituent to boost the repair of heart function through carrying noncoding RNAs and proteins. Given the advantages of higher stability in the circulation, lower toxicity, and controllable transplantation dosage, exosomes have been described as a wonderful and promising cell-free treatment method in cardiovascular disease. Nowadays, MSC-derived exosomes have been proposed as a promising therapeutic approach to improve cardiac function and reverse heart remodeling. However, exosomes' lack of modification cannot result in desired therapeutic effect. Hence, optimized exosomes can be developed via various engineering methods such as pharmacological compound preconditioned MSCs, genetically modified MSCs, or miRNA-loaded exosomes and peptide tagged exosomes to improve the targeting and therapeutic effects of exosomes. The biological characteristics, therapeutic potential, and optimizing strategy of exosomes will be described in our review.

Exosomes derived from human amniotic fluid mesenchymal stem cells alleviate cardiac fibrosis via enhancing angiogenesis in vivo and in vitro

Background

Cardiac fibrosis is a pathological process characterized by excess extracellular matrix (ECM) deposition and plays a critical role in nearly all types of heart disease. The mechanism of cardiac fibrosis is still unclear and no effective medication treatment of cardiac fibrosis. Research showed that mesenchymal stem cell (MSC) derived exosomes may play a critical role in cardiac fibrosis. The effect of human amniotic fluid MSC (hAFMSC)-derived exosomes (hAFMSCExos) on cardiac fibrosis has remained unclear.

Methods

The hAFMSCExos were extracted using a sequential centrifugation approach. The effects of hAFMSCExos on angiogenesis were analyzed both in human umbilical vein endothelial cells (HUVECs) after oxygen and glucose deprivation (OGD) in vitro, and in isoproterenol (ISO) induced-cardiac fibrosis in vivo.

Results

The hAFMSCExos remarkably up-regulate the motility and migration of HUVECs after OGD compared with phosphate-buffered saline (PBS). Meanwhile, total tube length, total branching points and total loops were significantly raised in HUVECs after OGD treated with hAFMSCExos. The hAFMSCExos alleviated the cardiac fibrosis degree tested by hematoxylin-eosin (H&E) and Masson staining. The protein levels of Collagen I and α-smooth muscle actin (α-SMA) were lower in exosomes group rats than PBS group. Immunofluorescence suggested that hAFMSCExos can promote the expression of CD31 in the rats. Meanwhile, the number of regenerated microvessels was significantly enhanced in rats administrated with exosomes by quantitative analysis of microvessel density. Furthermore, the micro-CT scanning evidenced that hAFMSCExos promote angiogenesis after cardiac fibrosis. The levels of hypoxia-inducible factor 1 α (HIF-1α) and vascular endothelial growth factor (VEGF) expression in the left ventricle accepted HUVECs were higher than PBS treatment at 7 days post-treatment by Western blot analysis.

Conclusions

The hAFMSCExos have proangiogenic effects on endothelial cells and enhanced angiogenesis in cardiac fibrosis. The hAFMSCExos may be a promising potential treatment strategy for cardiac fibrosis.

RETRACTED:BMSCs-derived exosomal microRNA-150-5p attenuates myocardial infarction in mice

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the reliability of the Western blot results in Figs. 2B and 7B, which appear to have the same eyebrow shaped phenotype as many other publications tabulated here (https://docs.google.com/spreadsheets/d/149EjFXVxpwkBXYJOnOHb6RhAqT4a2llhj9LM60MBffM/edit#gid=0 [docs.google.com]). Concerns were also raised over the provenance of the flow cytometry plots in Fig. 1F. The journal requested the corresponding author comment on these concerns and provide the raw data. However, the authors were not responsive to the request for comment.  Since original data could not be provided, the overall validity of the results could not be confirmed. Therefore, the Editor-in-Chief decided to retract the article.

LINC01303 promotes the proliferation and migration of laryngeal carcinoma by regulating miR-200c/TIMP2 axis

BACKGROUND

It is reported that long non-coding RNA is crucial in many cancer progressions. But the function and regulatory mechanism of LINC01303 in human laryngeal squamous cell carcinoma (LSCC) remains unclear. Hence, this research aims at investigating the biological function and potential mechanism of LINC01303 in LSCC.

METHODS

Real-time quantitative PCR (qRT-PCR) was applied for the determination of LINC01303, miR-200c and TIMP metallopeptidase inhibitor 2 (TIMP2) expression in LSCC tissues and cell lines. Corresponding experiments were carried out to determine the impacts of LINC01303 on LSCC cell proliferation, apoptosis, migration and invasion. The interaction between LINC01303 and miR-200c was analyzed with bioinformatics analysis and luciferase activity analysis.

RESULTS

LINC01303 expression in LSCC tissues was notably higher than that in adjacent normal tissues. High LINC01303 expression was bound up with lymphatic metastasis and advanced clinical stage. In addition, inhibition of LINC01303 by siRNA could evidently block LSCC cell proliferation, induce apoptosis, and inhibit invasion and migration. Mechanically, LINC01303 acted as carcinogenic lncRNA in LSCC by regulating miR-200c/TIMP2 axis.

CONCLUSION

LINC01303 plays a carcinogenic part in LSCC carcinogenesis through regulating miR-200c/TIMP2 axis, which may become a promising target of LSCC therapy.

Extracellular Vesicle-Based Therapeutics for Heart Repair

Extracellular vesicles (EVs) are constituted by a group of heterogeneous membrane vesicles secreted by most cell types that play a crucial role in cell–cell communication. In recent years, EVs have been postulated as a relevant novel therapeutic option for cardiovascular diseases, including myocardial infarction (MI), partially outperforming cell therapy. EVs may present several desirable features, such as no tumorigenicity, low immunogenic potential, high stability, and fine cardiac reparative efficacy. Furthermore, the natural origin of EVs makes them exceptional vehicles for drug delivery. EVs may overcome many of the limitations associated with current drug delivery systems (DDS), as they can travel long distances in body fluids, cross biological barriers, and deliver their cargo to recipient cells, among others. Here, we provide an overview of the most recent discoveries regarding the therapeutic potential of EVs for addressing cardiac damage after MI. In addition, we review the use of bioengineered EVs for targeted cardiac delivery and present some recent advances for exploiting EVs as DDS. Finally, we also discuss some of the most crucial aspects that should be addressed before a widespread translation to the clinical arena.