Mesenchymal stem cell exosome: a novel stem cell-based therapy for cardiovascular disease

Injectable extracellular vesicle hydrogels with tunable viscoelasticity for depot vaccine

Extracellular vesicles (EVs) have been actively explored for therapeutic applications in the context of cancer and other diseases. However, the poor tissue retention of EVs has limited the development of EV-based therapies. Here we report a facile approach to fabricating injectable EV hydrogels with tunable viscoelasticity and gelation temperature, by metabolically tagging EVs with azido groups and further crosslinking them with dibenzocyclooctyne-bearing polyethylene glycol via efficient click chemistry. One such EV gel has a gelation temperature of 39.4 °C, enabling in situ gelation of solution-form EVs upon injection into the body. The in situ formed gels are stable for over 4 weeks and can attract immune cells including dendritic cells over time in vivo. We further show that tumor EV hydrogels, upon subcutaneous injection, can serve as a long-term depot for EV-encased tumor antigens, providing an extended time for the modulation of dendritic cells and subsequent priming of tumor-specific CD8+ T cells. The tumor EV hydrogel also shows synergy with anti-PD-1 checkpoint blockade for tumor treatment, and is able to reprogram the tumor microenvironment. As a proof-of-concept, we also demonstrate that EV hydrogels can induce enhanced antibody responses than solution-form EVs over an extended time. Our study yields a facile and universal approach to fabricating injectable EV hydrogels with tunable mechanics and improving the therapeutic efficacy of EV-based therapies.

Mesenchymal stem cell secretome for regenerative medicine: Where do we stand?

BACKGROUND

Mesenchymal stem cell (MSC)-based therapies have yielded beneficial effects in a broad range of preclinical models and clinical trials for human diseases. In the context of MSC transplantation, it is widely recognized that the main mechanism for the regenerative potential of MSCs is not their differentiation, with in vivo data revealing transient and low engraftment rates. Instead, MSCs therapeutic effects are mainly attributed to its secretome, i.e., paracrine factors secreted by these cells, further offering a more attractive and innovative approach due to the effectiveness and safety of a cell-free product.

AIM OF REVIEW

In this review, we will discuss the potential benefits of MSC-derived secretome in regenerative medicine with particular focus on respiratory, hepatic, and neurological diseases. Both free and vesicular factors of MSC secretome will be detailed. We will also address novel potential strategies capable of improving their healing potential, namely by delivering important regenerative molecules according to specific diseases and tissue needs, as well as non-clinical and clinical studies that allow us to dissect their mechanisms of action.

KEY SCIENTIFIC CONCEPTS OF REVIEW

MSC-derived secretome includes both soluble and non-soluble factors, organized in extracellular vesicles (EVs). Importantly, besides depending on the cell origin, the characteristics and therapeutic potential of MSC secretome is deeply influenced by external stimuli, highlighting the possibility of optimizing their characteristics through preconditioning approaches. Nevertheless, the clarity around their mechanisms of action remains ambiguous, whereas the need for standardized procedures for the successful translation of those products to the clinics urges.

Mitochondria transfer for myelin repair

Demyelination is a common feature of neuroinflammatory and degenerative diseases of the central nervous system (CNS), such as multiple sclerosis (MS). It is often linked to disruptions in intercellular communication, bioenergetics and metabolic balance accompanied by mitochondrial dysfunction in cells such as oligodendrocytes, neurons, astrocytes, and microglia. Although current MS treatments focus on immunomodulation, they fail to stop or reverse demyelination's progression. Recent advancements highlight intercellular mitochondrial exchange as a promising therapeutic target, with potential to restore metabolic homeostasis, enhance immunomodulation, and promote myelin repair. With this review we will provide insights into the CNS intercellular metabolic decoupling, focusing on the role of mitochondrial dysfunction in neuroinflammatory demyelinating conditions. We will then discuss emerging cell-free biotherapies exploring the therapeutic potential of transferring mitochondria via biogenic carriers like extracellular vesicles (EVs) or synthetic liposomes, aimed at enhancing mitochondrial function and metabolic support for CNS and myelin repair. Lastly, we address the key challenges for the clinical application of these strategies and discuss future directions to optimize mitochondrial biotherapies. The advancements in this field hold promise for restoring metabolic homeostasis, and enhancing myelin repair, potentially transforming the therapeutic landscape for neuroinflammatory and demyelinating diseases.

Consensus statement on extracellular vesicles in liquid biopsy for advancing laboratory medicine

Extracellular vesicles (EVs) represent a diverse class of nanoscale membrane vesicles actively released by cells. These EVs can be further subdivided into categories like exosomes and microvesicles, based on their origins, sizes, and physical attributes. Significantly, disease-derived EVs have been detected in virtually all types of body fluids, providing a comprehensive molecular profile of their cellular origins. As a result, EVs are emerging as a valuable addition to liquid biopsy techniques. In this collective statement, the authors share their current perspectives on EV-related research and product development, with a shared commitment to translating this newfound knowledge into clinical applications for cancer and other diseases, particularly as disease biomarkers. The consensus within this document revolves around the overarching recognition of the merits, unresolved questions, and existing challenges surrounding EVs. This consensus manuscript is a collaborative effort led by the Committee of Exosomes, Society of Tumor Markers, Chinese anti-Cancer Association, aimed at expediting the cultivation of robust scientific and clinically applicable breakthroughs and propelling the field forward with greater swiftness and efficacy.

Mesenchymal Stem Cell-Derived Extracellular Vesicles Mitigate Immune Cell Activation in an In Vitro Model of Post-Resuscitation Inflammation

Background

Systemic inflammation is a well-established component of post-cardiac arrest syndrome (PCAS), a condition responsible for significant morbidity and mortality in patients who are initially resuscitated from sudden cardiac arrest. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have emerged as promising immunomodulatory agents in various inflammatory conditions, including after ischemia-reperfusion injury (IRI). Here, we investigated the therapeutic potential of MSC-EVs in porcine peripheral blood mononuclear cells (PBMCs) stimulated with lipopolysaccharide (LPS) or mitochondrial DNA (mtDNA) to mimic immune cell activation in PCAS.

Methods

PBMCs were isolated from healthy pigs ( Sus scrofa ), cultured in vitro , stimulated with LPS or mtDNA, and treated with a range of MSC-EV concentrations. Flow cytometry, quantitative PCR, ELISA, and ROS/RNS measurements were performed to assess PBMC activation.

Results

MSC-EV treatment reduced LPS-induced inflammatory granulocyte activation and selectively modulated cytokine transcripts, including IFNα, IL-1β, and TNF-α, in a concentration-dependent manner. Similar immunosuppressive effects were observed in mtDNA-stimulated PBMCs, where MSC-EVs attenuated dendritic cell activation and inflammatory cytokine release. Furthermore, higher concentrations of MSC-EVs significantly decreased ROS/RNS production in both LPS- and mtDNA-challenged PBMCs.

Conclusions

MSC-EVs exhibit potent immunomodulatory properties against LPS- and mtDNA-induced activation of porcine PBMCs, highlighting their broad capacity to modulate immune responses and mitigate oxidative stress induced by pro-inflammatory stimuli that are relevant to PCAS. These findings provide further support for the administration of MSCs, or MSC-EVs themselves, as a potential therapeutic intervention to target immune activation in PCAS and other disorders characterized by an acute systemic inflammatory state.

Isolation, identification, and challenges of extracellular vesicles: emerging players in clinical applications

Extracellular vesicles (EVs) serve as critical mediators of intercellular communication, encompassing exosomes, microvesicles, and apoptotic vesicles that play significant roles in diverse physiological and pathological contexts. Numerous studies have demonstrated that EVs derived from mesenchymal stem cells (MSC-EVs) play a pivotal role in facilitating tissue and organ repair, alleviating inflammation and apoptosis, enhancing the proliferation of endogenous stem cells within tissues and organs, and modulating immune function-these functions have been extensively utilized in clinical applications. The precise classification, isolation, and identification of MSC-EVs are essential for their clinical applications. This article provides a comprehensive overview of the biological properties of EVs, emphasizing both their advantages and limitations in isolation and identification methodologies. Additionally, we summarize the protein markers associated with MSC-EVs, emphasizing their significance in the treatment of various diseases. Finally, this article addresses the current challenges and dilemmas in developing clinical applications for MSC-EVs, aiming to offer valuable insights for future research.

Membrane-free stem cell components suppress osteoclast differentiation: Implications for oral regenerative treatment

Background/purpose

Membrane-free stem cell components (MFSCCs) have been developed by removing cell membranes with antigens to overcome the limitations associated with cell-based therapies and isolate effective peptides. MFSCCs have been reported to have effects on oral infection sites. Chronic inflammatory diseases cause excessive bone resorption. This study investigated the effects of MFSCCs on osteoclast differentiation in the context of the high prevalence of inflammatory bone resorption.

Materials and methods

Bone marrow macrophages (BMMs) were treated with macrophage colony-stimulating factor and receptor activator of nuclear factor kappa-B ligand. Osteoclast differentiation was assessed based on the MFSCC concentrations. Tartrate-resistant acid phosphatase (TRAP)-stained mature osteoclasts and multinucleated cells derived from BMMs were analyzed using light microscopy. The messenger RNA (mRNA) expression levels of genes related to osteoclast differentiation were measured using real-time polymerase chain reaction (RT-PCR). The relative expression levels of the key transcription factors c-fos and nuclear factor of activated T cells (NFATc1) were determined using quantitative RT-PCR and western blotting.

Results

After treatment with MFSCCs, the cell viability was similar, depending on the level of BMMs. As the MFSCC concentration increased, the number of TRAP-positive cells decreased. The mRNA and protein expression of cathepsin K, TRAP, dendritic cell-specific transmembrane protein, c-fos, and NFATc1 decreased as the MFSCC concentration increased.

Conclusion

Our findings demonstrate that MFSCCs suppress osteoclast differentiation by downregulating transcription factors, particularly, c-fos and NFATc1. Therefore, MFSCCs may serve as a conservative treatment option for chronic inflammatory bone resorption diseases of the oral cavity by suppressing excessive bone resorption.

Regenerative Medicine and Nanotechnology Approaches against Cardiovascular Diseases: Recent Advances and Future Prospective

Regenerative medicine refers to medical research focusing on repairing, replacing, or regenerating damaged or diseased tissues or organs. Cardiovascular disease (CVDs) is a significant health issue globally and is the leading cause of death in many countries. According to the Centers for Disease Control and Prevention (CDC), one person dies every 34 seconds in the United States from cardiovascular diseases, and according to a World Health Organization (WHO) report, cardiovascular diseases are the leading cause of death globally, taking an estimated 17.9 million lives each year. Many conventional treatments are available using different drugs for cardiovascular diseases, but these treatments are inadequate. Stem cells and nanotechnology are promising research areas for regenerative medicine treating CVDs. Regenerative medicines are a revolutionary strategy for advancing and successfully treating various diseases, intending to control cardiovascular disorders. This review is a comprehensive study of different treatment methods for cardiovascular diseases using different types of biomaterials as regenerative medicines, the importance of different stem cells in therapeutics, the expanded role of nanotechnology in treatment, the administration of several types of stem cells, their tracking, imaging, and the final observation of clinical trials on many different levels as well as it aims to keep readers up to pace on emerging therapeutic applications of some specific organs and disorders that may improve from regenerative medicine shortly.

Thermoresponsive gel embedding extracellular vesicles from adipose stromal cells improves the healing of colonic anastomoses following irradiation in rats

Anastomotic leak occurrence is a severe complication after colorectal surgery. Considering the difficulty of treating these leaks and their impact on patient care, there is a strong need for an efficient prevention strategy. We evaluated a combination of extracellular vesicles (EVs) from rat adipose-derived stromal cells with a thermoresponsive gel, Pluronic® F127 (PF-127) to prevent anastomotic leaks. The pro-regenerative and immunomodulatory potencies of EVs are assessed in vitro. In vivo efficacy are assessed in rat with a colonic anastomosis model after irradiation. Endoscopic, anatomical and histological data show a consistent effect of EVs + gel on the healing of colonic anastomosis. These results are illustrated by a smaller anastomotic ulcer size, less fibrosis and less inflammatory infiltrations in the EVs + gel group. This multi-modal investigation is the first to point-out the translational potential of EVs combined with PF-127 for the healing of high-risk colorectal anastomosis.

Exosomes Derived from Adipose Mesenhymal Stem Cells Ameliorate Lipid Metabolism Disturbances Following Liver Ischemia-Reperfusion Injury in Miniature Swine

The liver plays a crucial role in regulating lipid metabolism. Our study examined the impact of Exosomes derived from adipose mesenchymal stem cells (ADSCs-Exo) on lipid metabolism following liver ischemia-reperfusion injury (IRI) combined with partial hepatectomy. We developed a miniature swine model for a minimally invasive hemi-hepatectomy combined with liver IRI. In this study, we administered PBS, ADSCs-Exo, and adipose-derived stem cells (ADSCs) individually through the portal vein. Before and after surgery, we evaluated various factors including hepatocyte ultrastructure, lipid accumulation in liver tissue, and expression levels of genes and proteins associated with lipid metabolism. In addition, we measured serum and liver tissue levels of high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TG), and total cholesterol (CHOL). TEM and oil red O stain indicated a significant reduction in liver steatosis following ADSCs-Exo treatment, which also elevated serum levels of HDL, LDL, TG, and CHOL. Additionally, ADSCs-Exo have been shown to significantly decrease serum concentrations of HDL, LDL, TG, and CHOL in the liver (p < 0.05). Finally, ADSCs-Exo significantly downregulated lipid synthesis-related genes and proteins, including SREBP-1, SREBP-2, ACC1, and FASN (p < 0.05), while upregulating lipid catabolism-related genes and proteins, such as PPAR-α and ACOX1 (p < 0.05). ADSCs-Exo as a cell-free therapy highlights its therapeutic potential in hepatic lipid metabolism abnormalities.

Exosomal therapy is a luxury area for regenerative medicine

Stem cell-based therapies have made significant advancements in tissue regeneration and medical engineering. However, there are limitations to cell transplantation therapy, such as immune rejection and limited cell viability. These limitations greatly impede the translation of stem cell-based tissue regeneration into clinical practice. In recent years, exosomes, which are packaged vesicles released from cells, have shown promising progress. Specifically, exosomes derived from stem cells have demonstrated remarkable therapeutic benefits. Exosomes are nanoscale extracellular vesicles that act as paracrine mediators. They transfer functional cargos, such as miRNA and mRNA molecules, peptides, proteins, cytokines, and lipids, from MSCs to recipient cells. By participating in intercellular communication events, exosomes contribute to the healing of injured or diseased tissues and organs. Studies have shown that the therapeutic effects of MSCs in various experimental paradigms can be solely attributed to their exosomes. Consequently, MSC-derived exosomes can be modified and utilized to develop a unique cell-free therapeutic approach for treating multiple diseases, including neurological, immunological, heart, and other diseases. This review is divided into several categories, including the current understanding of exosome biogenesis, isolation techniques, and their application as therapeutic tools.

A comprehensive review of challenges and advances in exosome-based drug delivery systems

Exosomes or so-called natural nanoparticles have recently shown enormous potential for targeted drug delivery systems. Several studies have reported that exosomes as advanced drug delivery platforms offer efficient targeting of chemotherapeutics compared to individual polymeric nanoparticles or liposomes. Taking structural constituents of exosomes, viz., proteins, nucleic acids, and lipids, into consideration, exosomes are the most promising carriers as genetic messengers and for treating genetic deficiencies or tumor progression. Unfortunately, very little attention has been paid to the factors like source, scalability, stability, and validation that contribute to the quality attributes of exosome-based drug products. Some studies suggested that exosomes were stable at around -80 °C, which is impractical for storing pharmaceutical products. Currently, no reports on the shelf-life and in vivo stability of exosome formulations are available. Exosomes are quickly cleared from blood circulation, and their in vivo distribution depends on the source. Considering these challenges, further studies are necessary to address major limitations such as poor drug loading, reduced in vivo stability, a need for robust, economical, and scalable production methods, etc., which may unlock the potential of exosomes in clinical applications. A few reports based on hybrid exosomes involving hybridization between different cell/tumor/macrophage-derived exosomes with synthetic liposomes through membrane fusion have shown to overcome some limitations associated with natural or synthetic exosomes. Yet, sufficient evidence is indispensable to prove their stability and clinical efficacy.

Drug delivery based exosomes uptake pathways

Most cells secrete a material called extracellular vesicles (EVs), which play a crucial role in cellular communication. Exosomes are one of the most studied types of EVs. Recent research has shown the many functions and substrates of cellular exosomes. Multiple studies have shown the efficacy of exosomes in transporting a wide variety of cargo to their respective target cells. As a result, they are often utilized to transport medicaments to patients. Natural exosomes as well as exosomes modified with other compounds to enhance transport capabilities have been employed. In this article, we take a look at how different types of exosomes and modified exosomes may transport different types of cargo to their respective targets. Exosomes have a lot of potential as drug delivery vehicles for many synthetic compounds, proteins, nucleic acids, and gene repair specialists because they can stay in the body for a long time, are biocompatible, and can carry natural materials. A good way to put specific protein particles into exosomes is still not clear, though, and the exosomes can't be used in many situations yet. The determinants for exosome production, as well as ways for loading certain therapeutic molecules (proteins, nucleic acids, and small compounds), were covered in this paper. Further study and the development of therapeutic exosomes may both benefit from the information collected in this review.

Innovative Strategies for Liver Transplantation: The Role of Mesenchymal Stem Cells and Their Cell-Free Derivatives

Despite being the standard treatment for end-stage liver disease, liver transplantation has limitations like donor scarcity, high surgical costs, and immune rejection risks. Mesenchymal stem cells (MSCs) and their derivatives offer potential for liver regeneration and transplantation. MSCs, known for their multipotency, low immunogenicity, and ease of obtainability, can differentiate into hepatocyte-like cells and secrete bioactive factors that promote liver repair and reduce immune rejection. However, the clinical application of MSCs is limited by risks such as aberrant differentiation and low engraftment rates. As a safer alternative, MSC-derived secretomes and extracellular vesicles (EVs) offer promising therapeutic benefits, including enhanced graft survival, immunomodulation, and reduced ischemia-reperfusion injury. Current research highlights the efficacy of MSC-derived therapies in improving liver transplant outcomes, but further studies are necessary to standardize clinical applications. This review highlights the potential of MSCs and EVs to address key challenges in liver transplantation, paving the way for innovative therapeutic strategies.

Contents of exosomes derived from adipose tissue and their regulation on inflammation, tumors, and diabetes

Adipose tissue (AT) serves as an energy-capacitive organ and performs functions involving paracrine- and endocrine-mediated regulation via extracellular vesicles (EVs) secretion. Exosomes, a subtype of EVs, contain various bioactive molecules with regulatory effects, such as nucleic acids, proteins, and lipids. AT-derived exosomes (AT-exos) include exosomes derived from various cells in AT, including adipocytes, adipose-derived stem cells (ADSCs), macrophages, and endothelial cells. This review aimed to comprehensively evaluate the impacts of different AT-exos on the regulation of physiological and pathological processes. The contents and functions of adipocyte-derived exosomes and ADSC-derived exosomes are compared simultaneously, highlighting their similarities and differences. The contents of AT-exos have been shown to exert complex regulatory effects on local inflammation, tumor dynamics, and insulin resistance. Significantly, differences in the cargoes of AT-exos have been observed among diabetes patients, obese individuals, and healthy individuals. These differences could be used to predict the development of diabetes mellitus and as therapeutic targets for improving insulin sensitivity and glucose tolerance. However, further research is needed to elucidate the underlying mechanisms and potential applications of AT-exos.

Sorcin in Cancer Development and Chemotherapeutic Drug Resistance

SOluble Resistance-related Calcium-binding proteIN (sorcin) earned its name due to its co-amplification with ABCB1 in multidrug-resistant cells. Initially thought to be an accidental consequence of this co-amplification, recent research indicates that sorcin plays a more active role as an oncoprotein, significantly impacting multidrug resistance (MDR). Sorcin is a highly expressed calcium-binding protein, often overproduced in human tumors and multidrug-resistant cancers, and is a promising novel MDR marker. In tumors, sorcin levels inversely correlate with both patient response to chemotherapy and overall prognosis. Multidrug-resistant cell lines consistently exhibit higher sorcin expression compared to their parental counterparts. Furthermore, sorcin overexpression via gene transfection enhances drug resistance to various chemotherapeutic drugs across numerous cancer lines. Conversely, silencing sorcin expression reverses drug resistance in many cell lines. Sorcin participates in several mechanisms of MDR, including drug efflux, drug sequestering, cell death inhibition, gene amplification, epithelial-to-mesenchymal transition, angiogenesis, and metastasis. The present review focuses on the structure and function of sorcin, on sorcin's role in cancer and drug resistance, and on the approaches aimed at targeting sorcin.

The science of exosomes: Understanding their formation, capture, and role in cellular communication

Extracellular vesicles (EVs) serve as a crucial method for transferring information among cells, which is vital in multicellular organisms. Among these vesicles, exosomes are notable for their small size, ranging from 20 to 150 nm, and their role in cell-to-cell communication. They carry lipids, proteins, and nucleic acids between cells. The creation of exosomes begins with the inward budding of the cell membrane, which then encapsulates various macromolecules as cargo. Once filled, exosomes are released into the extracellular space and taken up by target cells via endocytosis and similar processes. The composition of exosomal cargo varies, encompassing diverse macromolecules with specific functions. Because of their significant roles, exosomes have been isolated from various cell types, including cancer cells, endothelial cells, macrophages, and mesenchymal cells, with the aim of harnessing them for therapeutic applications. Exosomes influence cellular metabolism, and regulate lipid, glucose, and glutamine pathways. Their role in pathogenesis is determined by their cargo, which can manipulate processes such as apoptosis, proliferation, inflammation, migration, and other molecular pathways in recipient cells. Non-coding RNA transcripts, a common type of cargo, play a pivotal role in regulating disease progression. Exosomes are implicated in numerous biological and pathological processes, including inflammation, cancer, cardiovascular diseases, diabetes, wound healing, and ischemic-reperfusion injury. As a result, they hold significant potential in the treatment of both cancerous and non-cancerous conditions.

Meta-analysis study of small extracellular vesicle nursing application therapies for healing of wounds and skin regeneration

We designed and performed this meta-analysis to investigate the impact of the application of extracellular small vesicle therapies on regeneration of skin and wound healing. The findings of this study were computed using fixed or random effect models. The mean differences (MDs), and odds ratio (ORs) with their 95% confidence intervals (CIs) were calculated. In this study, 43 publications were included, encompassing 530 animals with artificial wounds. Small extracellular vesicle therapy had a significant greater rate of wound closure (MD, 24.0; 95% CI, 19.98-28.02, P < 0.001), lower scar width (MD, -191.33; 95%CI, -292.26--90.4, P < 0.001), and higher blood vessel density (MD,36.11; 95%CI, 19.02-53.20, P < 0.001) compared to placebo. Our data revealed that small extracellular vesicle therapy had a significantly higher regeneration of skin and healing of wounds based on the results of wound closure rate, lower scar width, and higher blood vessel density compared to placebo. Future studies with larger sample size are needed.

Nanomaterials in crossroad of autophagy control in human cancers: Amplification of cell death mechanisms

Cancer is the result of genetic abnormalities that cause normal cells to grow into neoplastic cells. Cancer is characterized by several distinct features, such as uncontrolled cell growth, extensive spreading to other parts of the body, and the ability to resist treatment. The scientists have stressed the development of nanostructures as novel therapeutic options in suppressing cancer, in response to the emergence of resistance to standard medicines. One of the specific mechanisms with dysregulation during cancer is autophagy. Nanomaterials have the ability to specifically carry medications and genes, and they can also enhance the responsiveness of tumor cells to standard therapy while promoting drug sensitivity. The primary mechanism in this process relies on autophagosomes and their fusion with lysosomes to break down the components of the cytoplasm. While autophagy was initially described as a form of cellular demise, it has been demonstrated to play a crucial role in controlling metastasis, proliferation, and treatment resistance in human malignancies. The pharmacokinetic profile of autophagy modulators is poor, despite their development for use in cancer therapy. Consequently, nanoparticles have been developed for the purpose of delivering medications and autophagy modulators selectively and specifically to the cancer process. Furthermore, several categories of nanoparticles have demonstrated the ability to regulate autophagy, which plays a crucial role in defining the biological characteristics and response to therapy of tumor cells.

Harnessing the potential of mesenchymal stem cells-derived exosomes in degenerative diseases

Mesenchymal stem cells (MSCs) have gained attention as a promising therapeutic approach in both preclinical and clinical osteoarthritis (OA) settings. Various joint cell types, such as chondrocytes, synovial fibroblasts, osteoblasts, and tenocytes, can produce and release extracellular vesicles (EVs), which subsequently influence the biological activities of recipient cells. Recently, extracellular vesicles derived from mesenchymal stem cells (MSC-EVs) have shown the potential to modulate various physiological and pathological processes through the modulation of cellular differentiation, immune responses, and tissue repair. This review explores the roles and therapeutic potential of MSC-EVs in OA and rheumatoid arthritis, cardiovascular disease, age-related macular degeneration, Alzheimer's disease, and other degenerative diseases. Notably, we provide a comprehensive summary of exosome biogenesis, microRNA composition, mechanisms of intercellular transfer, and their evolving role in the highlight of exosome-based treatments in both preclinical and clinical avenues.

Research hotspots and emerging trends of mesenchymal stem cells in cardiovascular diseases: a bibliometric-based visual analysis

Background

Mesenchymal stem cells (MSCs) have important research value and broad application prospects in cardiovascular diseases (CVDs). However, few bibliometric analyses on MSCs in cardiovascular diseases are available. This study aims to provide a thorough review of the cooperation and influence of countries, institutions, authors, and journals in the field of MSCs in cardiovascular diseases, with the provision of discoveries in the latest progress, evolution paths, frontier research hotspots, and future research trends in the regarding field.

Methods

The articles related to MSCs in cardiovascular diseases were retrieved from the Web of Science. The bibliometric study was performed by CiteSpace and VOSviewer, and the knowledge map was generated based on data obtained from retrieved articles.

Results

In our study, a total of 4,852 publications launched before August 31, 2023 were accessed through the Web of Science Core Collection (WoSCC) database via our searching strategy. Significant fluctuations in global publications were observed in the field of MSCs in CVDs. China emerged as the nation with the largest number of publications, yet a shortage of high-quality articles was noted. The interplay among countries, institutions, journals and authors is visually represented in the enclosed figures. Importantly, current research trends and hotspots are elucidated. Cluster analysis on references has highlighted the considerable interest in exosomes, extracellular vesicles, and microvesicles. Besides, keywords analysis revealed a strong emphasis on myocardial infarction, therapy, and transplantation. Treatment methods-related keywords were prominent, while keywords associated with extracellular vesicles gathered significant attention from the long-term perspective.

Conclusion

MSCs in CVDs have become a topic of active research interest, showcasing its latent value and potential. By summarizing the latest progress, identifying the research hotspots, and discussing the future trends in the advancement of MSCs in CVDs, we aim to offer valuable insights for considering research prospects.

Mesenchymal Stromal Cells: New Generation Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, which has a high recurrence rate and is incurable due to a lack of effective treatment. Mesenchymal stromal cells (MSCs) are a class of pluripotent stem cells that have recently received a lot of attention due to their strong self-renewal ability and immunomodulatory effects, and a large number of experimental and clinical models have confirmed the positive therapeutic effect of MSCs on IBD. In preclinical studies, MSC treatment for IBD relies on MSCs paracrine effects, cell-to-cell contact, and its mediated mitochondrial transfer for immune regulation. It also plays a therapeutic role in restoring the intestinal mucosal barrier through the homing effect, regulation of the intestinal microbiome, and repair of intestinal epithelial cells. In the latest clinical trials, the safety and efficacy of MSCs in the treatment of IBD have been confirmed by transfusion of autologous or allogeneic bone marrow, umbilical cord, and adipose MSCs, as well as their derived extracellular vesicles. However, regarding the stable and effective clinical use of MSCs, several concerns emerge, including the cell sources, clinical management (dose, route and frequency of administration, and pretreatment of MSCs) and adverse reactions. This article comprehensively summarizes the effects and mechanisms of MSCs in the treatment of IBD and its advantages over conventional drugs, as well as the latest clinical trial progress of MSCs in the treatment of IBD. The current challenges and future directions are also discussed. This review would add knowledge into the understanding of IBD treatment by applying MSCs.

Injury minimization after myocardial infarction: focus on extracellular vesicles

Despite improvements in clinical outcomes following acute myocardial infarction, mortality remains high, especially in patients with severely reduced left ventricular ejection fraction (LVEF <30%), emphasizing the need for effective cardioprotective strategies adjunctive to recanalization. Traditional cell therapy has shown equivocal success, shifting the focus to innovative cardioactive biologicals and cell mimetic therapies, particularly extracellular vesicles (EVs). EVs, as carriers of non-coding RNAs and other essential biomolecules, influence neighbouring and remote cell function in a paracrine manner. Compared to cell therapy, EVs possess several clinically advantageous traits, including stability, ease of storage (enabling off-the-shelf clinical readiness), and decreased immunogenicity. Allogeneic EVs from mesenchymal and/or cardiac stromal progenitor cells demonstrate safety and potential efficacy in preclinical settings. This review delves into the translational potential of EV-based therapeutic approaches, specifically highlighting findings from large-animal studies, and offers a synopsis of ongoing early-stage clinical trials in this domain.

Exosome-coated oxygen nanobubble-laden hydrogel augments intracellular delivery of exosomes for enhanced wound healing

Wound healing is an obvious clinical concern that can be hindered by inadequate angiogenesis, inflammation, and chronic hypoxia. While exosomes derived from adipose tissue-derived stem cells have shown promise in accelerating healing by carrying therapeutic growth factors and microRNAs, intracellular cargo delivery is compromised in hypoxic tissues due to activated hypoxia-induced endocytic recycling. To address this challenge, we have developed a strategy to coat oxygen nanobubbles with exosomes and incorporate them into a polyvinyl alcohol/gelatin hybrid hydrogel. This approach not only alleviates wound hypoxia but also offers an efficient means of delivering exosome-coated nanoparticles in hypoxic conditions. The self-healing properties of the hydrogel, along with its component, gelatin, aids in hemostasis, while its crosslinking bonds facilitate hydrogen peroxide decomposition, to ameliorate wound inflammation. Here, we show the potential of this multifunctional hydrogel for enhanced healing, promoting angiogenesis, facilitating exosome delivery, mitigating hypoxia, and inhibiting inflammation in a male rat full-thickness wound model.

Dynamic cultivation of human mesenchymal stem/stromal cells for the production of extracellular vesicles in a 3D bioreactor system

PURPOSE

3D cell culture and hypoxia have been demonstrated to increase the therapeutic effects of mesenchymal stem/stromal cells (MSCs)-derived extracellular vesicles (EVs). In this study, a process for the production of MSC-EVs in a novel 3D bioreactor system under normoxic and hypoxic conditions was established and the resulting EVs were characterized.

METHODS

Human adipose-derived MSCs were seeded and cultured on a 3D membrane in the VITVO® bioreactor system for 7 days. Afterwards, MSC-EVs were isolated and characterized via fluorescence nanoparticle tracking analysis, flow cytometry with staining against annexin V (Anx5) as a marker for EVs exposing phosphatidylserine, as well as CD73 and CD90 as MSC surface markers.

RESULTS

Cultivation of MSC in the VITVO® bioreactor system demonstrated a higher concentration of MSC-EVs from the 3D bioreactor (9.1 × 109 ± 1.5 × 109 and 9.7 × 109 ± 3.1 × 109 particles/mL) compared to static 2D culture (4.2 × 109 ± 7.5 × 108 and 3.9 × 109 ± 3.0 × 108 particles/mL) under normoxic and hypoxic conditions, respectively. Also, the particle-to-protein ratio as a measure for the purity of EVs increased from 3.3 × 107 ± 1.1 × 107 particles/µg protein in 2D to 1.6 × 108 ± 8.3 × 106 particles/µg protein in 3D. Total MSC-EVs as well as CD73-CD90+ MSC-EVs were elevated in 2D normoxic conditions. The EV concentration and size did not differ significantly between normoxic and hypoxic conditions.

CONCLUSION

The production of MSC-EVs in a 3D bioreactor system under hypoxic conditions resulted in increased EV concentration and purity. This system could be especially useful in screening culture conditions for the production of 3D-derived MSC-EVs.

Standard Radio-Iodine Labeling Protocols Impaired the Functional Integrity of Mesenchymal Stem/Stromal Cell Exosomes

Mesenchymal stem/stromal cells (MSCs) are an extensively studied cell type in clinical trials due to their easy availability, substantial ex vivo proliferative capacity, and therapeutic efficacy in numerous pre-clinical animal models of disease. The prevailing understanding suggests that their therapeutic impact is mediated by the secretion of exosomes. Notably, MSC exosomes present several advantages over MSCs as therapeutic agents, due to their non-living nature and smaller size. However, despite their promising therapeutic potential, the clinical translation of MSC exosomes is hindered by an incomplete understanding of their biodistribution after administration. A primary obstacle to this lies in the lack of robust labels that are highly sensitive, capable of directly and easily tagging exosomes with minimal non-specific labeling artifacts, and sensitive traceability with minimal background noise. One potential candidate to address this issue is radioactive iodine. Protocols for iodinating exosomes and tracking radioactive iodine in live imaging are well-established, and their application in determining the biodistribution of exosomes has been reported. Nevertheless, the effects of iodination on the structural or functional activities of exosomes have never been thoroughly examined. In this study, we investigate these effects and report that these iodination methods abrogate CD73 enzymatic activity on MSC exosomes. Consequently, the biodistribution of iodinated exosomes may reflect the biodistribution of denatured exosomes rather than functionally intact ones.

Engineered exosomes enriched with select microRNAs amplify their therapeutic efficacy for traumatic brain injury and stroke

Traumatic brain injury (TBI) and stroke stand as prominent causes of global disability and mortality. Treatment strategies for stroke and TBI are shifting from targeting neuroprotection toward cell-based neurorestorative strategy, aiming to augment endogenous brain remodeling, which holds considerable promise for the treatment of TBI and stroke. Compelling evidence underscores that the therapeutic effects of cell-based therapy are mediated by the active generation and release of exosomes from administered cells. Exosomes, endosomal derived and nano-sized extracellular vesicles, play a pivotal role in intercellular communication. Thus, we may independently employ exosomes to treat stroke and TBI. Systemic administration of mesenchymal stem cell (MSC) derived exosomes promotes neuroplasticity and neurological functional recovery in preclinical animal models of TBI and stroke. In this mini review, we describe the properties of exosomes and recent exosome-based therapies of TBI and stroke. It is noteworthy that the microRNA cargo within exosomes contributes to their therapeutic effects. Thus, we provide a brief introduction to microRNAs and insight into their key roles in mediating therapeutic effects. With the increasing knowledge of exosomes, researchers have "engineered" exosome microRNA content to amplify their therapeutic benefits. We therefore focus our discussion on the therapeutic benefits of recently employed microRNA-enriched engineered exosomes. We also discuss the current opportunities and challenges in translating exosome-based therapy to clinical applications.

M2 macrophage exosome-derived lncRNA AK083884 protects mice from CVB3-induced viral myocarditis through regulating PKM2/HIF-1α axis mediated metabolic reprogramming of macrophages

Viral myocarditis (VM) is a clinically common inflammatory disease. Accumulating literature has indicated that M2 macrophages protect mice from Coxsackievirus B3 (CVB3)-induced VM. However, mechanisms that underlie M2 macrophages alleviating myocardial inflammation remain largely undefined. We found that M2 macrophage-derived exosomes (M2-Exo) can effectively attenuate VM. The long non-coding RNA (lncRNA) AK083884 in M2-Exo was found to be involved in the regulation of macrophage polarization by exosome lncRNA sequencing combined with in vitro functional assays. M2-Exo-derived AK083884 promotes macrophage M2 polarization and protects mice from CVB3-induced VM. Furthermore, we identified pyruvate kinase M2 (PKM2) as a protein target binding to AK083884 and found that PKM2 knockdown could promote macrophages to polarize to M2 phenotype. Intriguingly, functional assay revealed that downregulation of AK083884 promotes metabolic reprogramming in macrophages. In addition, co-immunoprecipitation was performed to reveal AK083884 could interact with PKM2 and inhibition of AK083884 can facilitate the binding of PKM2 and HIF-1α. Collectively, our findings uncovered an important role of M2-Exo-derived AK083884 in the regulation of macrophage polarization through metabolic reprogramming, identified a new participant in the development of VM and provided a potential clinically important therapeutic target.

Protective effect of oral stem cells extracellular vesicles on cardiomyocytes in hypoxia-reperfusion

Hypoxia signaling plays an important role in physiological and pathological conditions. Hypoxia in the heart tissue can produce different consequences depending on the duration of exposure to the hypoxic state. While acute hypoxic exposure leads to a reversible acclimatization in heart tissue with normal systemic oxygen supply, chronic hypoxia exacerbates cardiac dysfunction, leads to a destruction of the tissue. Extracellular vesicles (EVs) are small membrane vesicles that act as mediators of intercellular communication. EVs are secreted by different cell types and those produced by oral cavity-derived mesenchymal stem cells (MSCs), including human gingival MSCs (hGMSCs), have pro-angiogenic and anti-inflammatory effects and showed therapeutic role in tissue regeneration. The aim of the present work was to evaluate the potential protective and regenerative role of EVs produced by hGMSCs, in an in vitro model of hypoxia-conditioned HL-1 cardiomyocytes through the expression analysis of following inflammatory, oxidative stress, angiogenesis, cell survival and apoptotic markers: HIF-1α, P300, NFkB, CCL2, IL1B, IL6, NRF2, CASP-3, BAX and VEGF. Results showed that hGMSCs-derived EVs exerted protection HL-1 cardiomyocytes exposed to both pre and post hypoxic conditions. Moreover, modulation of CASP3 and BAX expression demonstrated that EVs reduced the apoptosis. The analysis of microRNAs in EVs derived from hGMSCs was performed to assess the epigenetic regulation of the presented markers. The following microRNAs: hsa-miR-138-5p, hsa-miR-17-5p, hsa-miR-18a-5p, hsa-miR-21-5p, hsa-miR-324-5p, hsa-miR-133a-3p, hsa-miR-150-5p, hsa-miR-199a-5p, hsa-miR-128-3p and hsa-miR-221-3p can directly or indirectly target the studied genes by determining their modulation obtained in our study. The data from this study suggested that EVs obtained from hGMSCs may be considered for the cell free treatment option in hypoxia-driven cardiac tissue dysfunction.

Stem Cell-Derived Extracellular Vesicles for Cancer Therapy and Tissue Engineering Applications

Recently, stem cells and their secretomes have attracted great attention in biomedical applications, particularly extracellular vesicles (EVs). EVs are secretomes of cells for cell-to-cell communication. They play a role as intercellular messengers as they carry proteins, nucleic acids, lipids, and therapeutic agents. They have also been utilized as drug-delivery vehicles due to their biocompatibility, low immunogenicity, stability, targetability, and engineerable properties. The therapeutic potential of EVs can be further enhanced by surface engineering and modification using functional molecules such as aptamers, peptides, and antibodies. As a consequence, EVs hold great promise as effective delivery vehicles for enhancing treatment efficacy while avoiding side effects. Among various cell types that secrete EVs, stem cells are ideal sources of EVs because stem cells have unique properties such as self-renewal and regenerative potential for transplantation into damaged tissues that can facilitate their regeneration. However, challenges such as immune rejection and ethical considerations remain significant hurdles. Stem cell-derived EVs have been extensively explored as a cell-free approach that bypasses many challenges associated with cell-based therapy in cancer therapy and tissue regeneration. In this review, we summarize and discuss the current knowledge of various types of stem cells as a source of EVs, their engineering, and applications of EVs, focusing on cancer therapy and tissue engineering.

The microRNAs (miRs) overexpressing mesenchymal stem cells (MSCs) therapy in neurological disorders; hope or hype

Altered expression of multiple miRNAs was found to be extensively involved in the pathogenesis of different neurological disorders including Alzheimer's disease, Parkinson's disease, stroke, epilepsy, multiple sclerosis, amyotrophic lateral sclerosis, and Huntington's disease. One of the biggest concerns within gene-based therapy is the delivery of the therapeutic microRNAs to the intended place, which is obligated to surpass the biological barriers without undergoing degradation in the bloodstream or renal excretion. Hence, the delivery of modified and unmodified miRNA molecules using excellent vehicles is required. In this light, mesenchymal stem cells (MSCs) have attracted increasing attention. The MSCs can be genetically modified to express or overexpress a particular microRNA aimed with promote neurogenesis and neuroprotection. The current review has focused on the therapeutic capabilities of microRNAs-overexpressing MSCs to ameliorate functional deficits in neurological conditions.

MicroRNA and Protein Cargos of Human Limbal Epithelial Cell-Derived Exosomes and Their Regulatory Roles in Limbal Stromal Cells of Diabetic and Non-Diabetic Corneas

Epithelial and stromal/mesenchymal limbal stem cells contribute to corneal homeostasis and cell renewal. Extracellular vesicles (EVs), including exosomes (Exos), can be paracrine mediators of intercellular communication. Previously, we described cargos and regulatory roles of limbal stromal cell (LSC)-derived Exos in non-diabetic (N) and diabetic (DM) limbal epithelial cells (LECs). Presently, we quantify the miRNA and proteome profiles of human LEC-derived Exos and their regulatory roles in N- and DM-LSC. We revealed some miRNA and protein differences in DM vs. N-LEC-derived Exos' cargos, including proteins involved in Exo biogenesis and packaging that may affect Exo production and ultimately cellular crosstalk and corneal function. Treatment by N-Exos, but not by DM-Exos, enhanced wound healing in cultured N-LSCs and increased proliferation rates in N and DM LSCs vs. corresponding untreated (control) cells. N-Exos-treated LSCs reduced the keratocyte markers ALDH3A1 and lumican and increased the MSC markers CD73, CD90, and CD105 vs. control LSCs. These being opposite to the changes quantified in wounded LSCs. Overall, N-LEC Exos have a more pronounced effect on LSC wound healing, proliferation, and stem cell marker expression than DM-LEC Exos. This suggests that regulatory miRNA and protein cargo differences in DM- vs. N-LEC-derived Exos could contribute to the disease state.

A review on renal autologous cell transplantation: an investigational approach towards chronic kidney disease

Chronic kidney disease is among the most common causes of mortality and morbidity in adult population with limited therapeutic approaches including various medications and kidney replacement therapies. Kidney transplantation is the gold standard therapeutic alternative for the management of chronic kidney disease; nonetheless, important drawbacks include the lack of adequate living or deceased donors, high rates of pre- and post-operative complications including surgical complications, infectious complications and medication-induced adverse effects. With the latest preclinical and in vitro studies demonstrating the potentiality of kidney cells obtained from diseased kidneys to convert into fully functional kidney cells lead to a novel therapeutic alternative referred as autologous selected renal cell transplantation. Even though the clinical studies investigating the efficiency and adverse effects of autologous selected renal cell transplantation are limited, it is no doubt promising. The need for future large-scale studies on chronic kidney disease patients from a diversity of etiologies is clear for the better establishment of the therapeutic potential of autologous selected renal cell transplantation. In this narrative review, our aim is to evaluate the role of renal autologous stem cell therapy in the management of chronic kidney disease.

Mesenchymal Stem Cell Therapies Approved by Regulatory Agencies around the World

Cellular therapy has used mesenchymal stem cells (MSCs), which in cell culture are multipotent progenitors capable of producing a variety of cells limited to the mesoderm layer. There are two types of MSC sources: (1) adult MSCs, which are obtained from bone marrow, adipose tissue, peripheral blood, and dental pulp; and (2) neonatal-tissue-derived MSCs, obtained from extra-embryonic tissues such as the placenta, amnion, and umbilical cord. Until April 2023, 1120 registered clinical trials had been using MSC therapies worldwide, but there are only 12 MSC therapies that have been approved by regulatory agencies for commercialization. Nine of the twelve MSC-approved products are from Asia, with Republic of Korea being the country with the most approved therapies. In the future, MSCs will play an important role in the treatment of many diseases. However, there are many issues to deal with before their application and usage in the medical field. Some strategies have been proposed to face these problems with the hope of reaching the objective of applying these MSC therapies at optimal therapeutic levels.

A Feedback Loop Involving Exosomal miR-146a and NG2 to Propel the Development and Progression of Hypothyroidism

Background: Thyrotropin receptor (TSHR) plays a central role in maintaining thyroid function and TSHR impairment causes hypothyroidism, which is often associated with metabolic disarrangement. The most common type of hypothyroidism is autoimmune disease-related and the mechanism, particularly with respect to the role of microRNAs (miRNAs), has not been delineated. Methods: Serum from 30 patients with subclinical hypothyroidism (SCH) and 30 healthy individuals were collected and exosomal miR-146a (exo-miR-146a) was examined, followed by extensive mechanistic investigation using various molecular and cellular experimental approaches and genetic-knockout mouse models. Results: Our clinical investigation showed that exo-miR-146a was systemically elevated in the serum of patients with SCH (p = 0.04) compared with healthy individuals, prompting us to investigate the biological effects of miR-146a in cells. We found that miR-146a could target and down-regulate neuron-glial antigen 2 (Ng2), with consequent down-regulation of TSHR. We next generated a thyroid-specific Ng2 knockout (Thy-Ng2-/-) mouse model and found a significant down-regulation of TSHR in Thy-Ng2-/- mice, accompanied by the development of hypothyroidism and metabolic disorders. We further found that a decrease in NG2 resulted in decreased receptor tyrosine kinase-linked downstream signaling and down-regulation of c-Myc, consequently resulting in up-regulation of miR-142 and miR-146a in thyroid cells. Up-regulated miR-142 targeted the 3'-untranslated region (UTR) of TSHR messenger RNA (mRNA) and post-transcriptionally down-regulated TSHR, explaining the development of hypothyroidism above. Local up-regulation of miR-146a in thyroid cells augments the earlier cited processes initiated by systemically elevated miR-146a, thereby forming a feedback loop to propel the development and progression of hypothyroidism. Conclusions: This study has uncovered a self-augmenting molecular loop initiated by elevated exo-miR-146a to suppress TSHR through targeting and down-regulating NG2, thereby initiating and propelling the development and progression of hypothyroidism.

The developing role of extracellular vesicles in autoimmune diseases: special attention to mesenchymal stem cell-derived extracellular vesicles

Autoimmune diseases are complex, chronic inflammatory conditions initiated by the loss of immunological tolerance to self-antigens. Nowadays, there is no effective and useful therapy for autoimmune diseases, and the existing medications have some limitations due to their nonspecific targets and side effects. During the last few decades, it has been established that mesenchymal stem cells (MSCs) have immunomodulatory functions. It is proposed that MSCs can exert an important therapeutic effect on autoimmune disorders. In parallel with these findings, several investigations have shown that MSCs alleviate autoimmune diseases. Intriguingly, the results of studies have demonstrated that the effective roles of MSCs in autoimmune diseases do not depend on direct intercellular communication but on their ability to release a wide spectrum of paracrine mediators such as growth factors, cytokines and extracellular vehicles (EVs). EVs that range from 50 to 5,000 nm were produced by almost any cell type, and these nanoparticles participate in homeostasis and intercellular communication via the transfer of a broad range of biomolecules such as modulatory proteins, nucleic acids (DNA and RNA), lipids, cytokines, and metabolites. EVs derived from MSCs display the exact properties of MSCs and can be safer and more beneficial than their parent cells. In this review, we will discuss the features of MSCs and their EVs, EVs biogenesis, and their cargos, and then we will highlight the existing discoveries on the impacts of EVs from MSCs on autoimmune diseases such as multiple sclerosis, arthritis rheumatic, inflammatory bowel disease, Type 1 diabetes mellitus, systemic lupus erythematosus, autoimmune liver diseases, Sjögren syndrome, and osteoarthritis, suggesting a potential alternative for autoimmune conditions therapy.

Disease-microenvironment modulation by bare- or engineered-exosome for rheumatoid arthritis treatment

BACKGROUND

Exosomes are extracellular vesicles secreted by eukaryotic cells and have been extensively studied for their surface markers and internal cargo with unique functions. A deeper understanding of exosomes has allowed their application in various research areas, particularly in diagnostics and therapy.

MAIN BODY

Exosomes have great potential as biomarkers and delivery vehicles for encapsulating therapeutic cargo. However, the limitations of bare exosomes, such as rapid phagocytic clearance and non-specific biodistribution after injection, pose significant challenges to their application as drug delivery systems. This review focuses on exosome-based drug delivery for treating rheumatoid arthritis, emphasizing pre/post-engineering approaches to overcome these challenges.

CONCLUSION

This review will serve as an essential resource for future studies to develop novel exosome-based therapeutic approaches for rheumatoid arthritis. Overall, the review highlights the potential of exosomes as a promising therapeutic approach for rheumatoid arthritis treatment.

Combining Piezoelectric Stimulation and Extracellular Vesicles for Cartilage Regeneration

Numerous patients experience articular cartilage defects (ACDs), which are characterized by progressive cartilage degradation and often lead to osteoarthritis (OA). Consequently, 44.7% of OA patients suffer from dyskinesia or disability. Current clinical drug treatments offer limited effectiveness in fully curing the disease. In this study, we propose a collaborative approach that combines physical and biological cues to promote cartilage regeneration. A biodegradable piezoelectric poly (l-lactic acid) (PLLA) nanofiber scaffold facilitates in situ, battery-free electrical stimulation under natural joint loading, while extracellular vesicles (EVs) serve as communication mediators between cells and promote cell proliferation, migration, and secretion of type II collagen. In this combined approach, EVs attached to PLLA are gradually released by localized piezoelectric electrical stimulation and taken up by chondrocytes. This process results in the organization of type II collagen along the PLLA fiber surface, ultimately forming cartilage lacunae that facilitate the residence of new chondrocytes. As an outcome, a significant round cartilage defect (diameter: 3 mm and depth: 1 mm) in the PLLA/EVs group (rat and knee) was rapidly restored within six weeks. In contrast, individual EVs and PLLA groups demonstrated considerably weaker cartilage regeneration capabilities. This research suggests that the synergistic effect of electromechanical stimulation and EVs-based biological cues is a crucial intervention method for treating OA.

Mesenchymal stem cell-derived exosomal miR-27b-3p alleviates liver fibrosis via downregulating YAP/LOXL2 pathway

Lysyl oxidase-like 2 (LOXL2) is an extracellular copper-dependent enzyme that plays a central role in fibrosis by catalyzing the crosslinking and deposition of collagen. Therapeutic LOXL2 inhibition has been shown to suppress liver fibrosis progression and promote its reversal. This study investigates the efficacy and underlying mechanisms of human umbilical cord-derived exosomes (MSC-ex) in LOXL2 inhibition of liver fibrosis. MSC-ex, nonselective LOX inhibitor β-aminopropionitrile (BAPN), or PBS were administered into carbon tetrachloride (CCl4)-induced fibrotic livers. Serum LOXL2 and collagen crosslinking were assessed histologically and biochemically. MSC-ex's mechanisms on LOXL2 regulation were investigated in human hepatic stellate cell line LX-2. We found that systemic administration of MSC-ex significantly reduced LOXL2 expression and collagen crosslinking, delaying the progression of CCl4-induced liver fibrosis. Mechanically, RNA-sequencing and fluorescence in situ hybridization (FISH) indicated that miR-27b-3p was enriched in MSC-ex and exosomal miR-27b-3p repressed Yes-associated protein (YAP) expression by targeting its 3' untranslated region in LX-2. LOXL2 was identified as a novel downstream target gene of YAP, and YAP bound to the LOXL2 promoter to positively regulate transcription. Additionally, the miR-27b-3p inhibitor abrogated the anti-LOXL2 abilities of MSC-ex and diminished the antifibrotic efficacy. miR-27b-3p overexpression promoted MSC-ex mediated YAP/LOXL2 inhibition. Thus, MSC-ex may suppress LOXL2 expression through exosomal miR-27b-3p mediated YAP down-regulation. The findings here may improve our understanding of MSC-ex in liver fibrosis alleviation and provide new opportunities for clinical treatment.

Extracellular Vesicles and Their Mimetics: A Comparative Study of Their Pharmacological Activities and Immunogenicity Profiles

Extracellular vesicles (EVs), which are miniaturised carriers loaded with functional proteins, lipids, and nucleic acid material, are naturally secreted by cells and show intrinsic pharmacological effects in several conditions. As such, they have the potential to be used for the treatment of various human diseases. However, the low isolation yield and laborious purification process are obstacles to their translation for clinical use. To overcome this problem, our lab developed cell-derived nanovesicles (CDNs), which are EV mimetics produced by shearing cells through membrane-fitted spin cups. To evaluate the similarities between EVs and CDNs, we compare the physical properties and biochemical composition of monocytic U937 EVs and U937 CDNs. Besides having similar hydrodynamic diameters, the produced CDNs had proteomic, lipidomic, and miRNA profiles with key communalities compared to those of natural EVs. Further characterisation was conducted to examine if CDNs could exhibit similar pharmacological activities and immunogenicity when administered in vivo. Consistently, CDNs and EVs modulated inflammation and displayed antioxidant activities. EVs and CDNs both did not exert immunogenicity when administered in vivo. Overall, CDNs could serve as a scalable and efficient alternative to EVs for further translation into clinical use.

Mesenchymal Stem Cell Exosomes as Immunomodulatory Therapy for Corneal Scarring

Corneal scarring is a leading cause of worldwide blindness. Human mesenchymal stem cells (MSC) have been reported to promote corneal wound healing through secreted exosomes. This study investigated the wound healing and immunomodulatory effects of MSC-derived exosomes (MSC-exo) in corneal injury through an established rat model of corneal scarring. After induction of corneal scarring by irregular phototherapeutic keratectomy (irrPTK), MSC exosome preparations (MSC-exo) or PBS vehicle as controls were applied to the injured rat corneas for five days. The animals were assessed for corneal clarity using a validated slit-lamp haze grading score. Stromal haze intensity was quantified using in-vivo confocal microscopy imaging. Corneal vascularization, fibrosis, variations in macrophage phenotypes, and inflammatory cytokines were evaluated using immunohistochemistry techniques and enzyme-linked immunosorbent assays (ELISA) of the excised corneas. Compared to the PBS control group, MSC-exo treatment group had faster epithelial wound closure (0.041), lower corneal haze score (p = 0.002), and reduced haze intensity (p = 0.004) throughout the follow-up period. Attenuation of corneal vascularisation based on CD31 and LYVE-1 staining and reduced fibrosis as measured by fibronectin and collagen 3A1 staining was also observed in the MSC-exo group. MSC-exo treated corneas also displayed a regenerative immune phenotype characterized by a higher infiltration of CD163+, CD206+ M2 macrophages over CD80+, CD86+ M1 macrophages (p = 0.023), reduced levels of pro-inflammatory IL-1β, IL-8, and TNF-α, and increased levels of anti-inflammatory IL-10. In conclusion, topical MSC-exo could alleviate corneal insults by promoting wound closure and reducing scar development, possibly through anti-angiogenesis and immunomodulation towards a regenerative and anti-inflammatory phenotype.

Engineered NF-κB siRNA-encapsulating exosomes as a modality for therapy of skin lesions

Introduction

Despite the protection and management of skin has been paid more and more attention, effective countermeasures are still lacking for patients suffering from UV or chemotherapy with damaged skin. Recently, gene therapy by small interfering RNA (siRNA) has emerged as a new therapeutic strategy for skin lesions. However, siRNA therapy has not been applied to skin therapy due to lack of effective delivery vector.

Methods

Here, we develop a synthetic biology strategy that integrates the exosomes with artificial genetic circuits to reprogram the adipose mesenchymal stem cell to express and assemble siRNAs into exosomes and facilitate in vivo delivery siRNAs for therapy of mouse models of skin lesions.

Results

Particularly, siRNA enriched exosomes (si-ADMSC-EXOs) could be directly taken up by the skin cells to inhibit the expression of skin injury related genes. When mice with skin lesions were smeared with si-ADMSC-EXOs, the repair of lesioned skin became faster and the expression of inflammatory cytokines were decreased.

Discussion

Overall, this study establishes a feasible therapeutic strategy for skin injury, which may offer an alternative to conventional biological therapies requiring two or more independent compounds.

Extracellular vesicles from hypoxia-pretreated adipose-derived stem cells regulate hypoxia/reoxygenation-induced human dermal microvascular endothelial apoptosis and autophagy in vitro

Recent studies suggest hypoxia can promote adipose-derived stem cells (ADSCs) to attenuate hypoxia/reoxygenation (H/R)-induced damage to human dermal microvascular endothelial cells (HDMECs). Extracellular vesicles (EVs), isolated from ADSCs, play an-important role in the fields of regenerative medicine. Here, we aimed to investigate the effect of EVs isolated from hypoxia-pretreated ADSCs (ADSC-EVs[H]) on HDMECs to attenuate ischemia/reperfusion injury of free skin flaps. First, we characterized EVs isolated from normoxia-cultured ADSCs (ADSC-EVs[N]) and ADSC-EVs(H). Experimental data indicated that EVs isolated from ADSCs consisted of lipid-bilayer vesicles that exhibited positive expression of vascular endothelial growth factor (VEGF) and marker proteins CD9, CD63 and CD81, and the mean particle size of EVs in the hypoxia-pretreated ADSCs (ADSC[H]) group was smaller (74.17 nm) than in the normoxic-cultured ADSCs (ADSC[N]) group (93.87 nm). Hypoxic pretreatment increased the number of EVs. Later, we favorably constructed the co-culture model of EVs isolated from ADSCs (ADSC-EVs) and H/R-induced HDMECs. Cell counting kit-8, Ethynyldeoxyuridine assay, western blotting and immunofluorescence staining showed that ADSC-EVs(H) promoted the survival of HDMECs and increased LC3 level. Apoptosis, reactive oxygen species (ROS) and JC-1 mitochondrial membrane potential (MMP) assays revealed that ADSC-EVs(H) reduced the apoptosis rate and ROS accumulation and increased MMP level in HDMECs, indicating that ADSC-EVs(H) effectively attenuated H/R-induced damage in HDMECs through autophagy activation and the-inhibition of apoptosis and oxidative stress. This study confirmed that ADSC-EVs(H) could effectively regulate the proliferation, apoptosis, oxidative stress, and autophagy expression of H/R-induced HDMECs in vitro, and therefore the transplantation of ADSC-EVs(H) may provide novel insights for the transplantation of free skin flaps.

The role of miRNAs from mesenchymal stem/stromal cells-derived extracellular vesicles in neurological disorders

Mesenchymal stem/stromal cells (MSCs) are multipotent cells with immunomodulatory effects that have been attempted as a possible treatment for neurologic disorders. Since currently available drugs for neurologic disorders are limited, special attention has been paid to MSCs. With the ability to differentiate into neural cells, it has been shown that MSCs exert their effects in a paracrine manner by producing extracellular vesicles (EVs). Extracellular vesicles are small vesicles with a size of 30-1000 nm that are released by cells, such as MSCs, T cells, B cells, etc. EVs contain various molecules, including proteins, lipids, mRNAs, and microRNAs (miRNAs). In recent years, the administration of EVs in models of neurological disorders has been shown to improve neurological dysfunctions. miRNAs from MSC-EVs as one of the important mediators which regulate various genes and reduce neuropathological change have been identified in different neurological disorders. Here, we review the effects of EVs miRNAs from MSCs on different neurological disorders and their potential applications.

Mesenchymal Stem Cell-Derived Extracellular Vesicles: The Novel Therapeutic Option for Regenerative Dentistry

Dental mesenchymal stem cells (MSCs) are characterized by unlimited self-renewal ability and high multidirectional differentiation potential. Since dental MSCs can be easily isolated and exhibit a high capability to differentiate into odontogenic cells, they are considered as attractive therapeutic agents in regenerative dentistry. Recently, MSC-derived extracellular vesicles (MSC-EVs) have attracted widespread attention as carriers for cell-free therapy due to their potential functions. Many studies have shown that MSC-EVs can mediate microenvironment at tissue damage site, and coordinate the regeneration process. Additionally, MSC-EVs can mediate intercellular communication, thus affecting the phenotypes and functions of recipient cells. In this review, we mainly summarized the types of MSCs that could be potentially applied in regenerative dentistry, the possible molecular cargos of MSC-EVs, and the major effects of MSC-EVs on the therapeutic induction of osteogenic differentiation.

Controlled release of canine MSC-derived extracellular vesicles by cationized gelatin hydrogels

Introduction

Canine mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) have emerged as a promising form of regenerative therapy. Therapeutic application of EVs remains difficult due to the short half-life of EVs in vivo and their rapid clearance from the body. We have developed cationized gelatin hydrogels that prolong the retention of EVs to overcome this problem.

Methods

Canine MSCs were isolated from bone marrow. MSC-derived EVs were isolated from the culture supernatant by ultracentrifugation. Gelatin was mixed with ethylene diamine anhydrate to cationized. Distinct cross-linked cationized gelatin hydrogels were created by thermal dehydration. Hydrogels were implanted into the back subcutis of mice in order to evaluate the degradation profiles. Hydrogels with collagenase were incubated at 37 °C in vitro to quantize the release of EVs from hydrogels. Lipopolysaccharide (LPS)-stimulated BV-2 cells were used to evaluate the immunomodulatory effect of EVs after release from the hydrogels.

Results

The cationized gelatin hydrogels suppressed EV release in PBS. More than 60% of immobilized EVs are not released from the hydrogels. The cationized hydrogels released EVs in a sustainable manner and prolonged the retention time of EVs depending on the intensity of cross-linking after degradation by collagenase. The expression of IL-1β in LPS-stimulated BV-2 cells was lower in EVs released from the hydrogels than in controls.

Conclusions

Our results indicate that the controlled release of EVs can be achieved by cationized gelatin hydrogels. The released EVs experimentally confirmed to be effective in reducing proinflammatory response. The cationized gelatin hydrogels appear to be useful biomaterials for releasing canine MSC-derived EVs for regenerative therapy.

Tumor-Derived Small Extracellular Vesicles Involved in Breast Cancer Progression and Drug Resistance

Breast cancer is one of the most serious and terrifying threats to the health of women. Recent studies have demonstrated that interaction among cancer cells themselves and those with other cells, including immune cells, in a tumor microenvironment potentially and intrinsically regulate and determine cancer progression and metastasis. Small extracellular vesicles (sEVs), a type of lipid-bilayer particles derived from cells, with a size of less than 200 nm, are recognized as one form of important mediators in cell-to-cell communication. sEVs can transport a variety of bioactive substances, including proteins, RNAs, and lipids. Accumulating evidence has revealed that sEVs play a crucial role in cancer development and progression, with a significant impact on proliferation, invasion, and metastasis. In addition, sEVs systematically coordinate physiological and pathological processes, such as coagulation, vascular leakage, and stromal cell reprogramming, to bring about premetastatic niche formation and to determine metastatic organ tropism. There are a variety of oncogenic factors in tumor-derived sEVs that mediate cellular communication between local stromal cells and distal microenvironment, both of which are important in cancer progression and metastasis. Tumor-derived sEVs contain substances that are similar to parental tumor cells, and as such, sEVs could be biomarkers in cancer progression and potential therapeutic targets, particularly for predicting and preventing future metastatic development. Here, we review the mechanisms underlying the regulation by tumor-derived sEVs on cancer development and progression, including proliferation, metastasis, drug resistance, and immunosuppression, which coordinately shape the pro-metastatic microenvironment. In addition, we describe the application of sEVs to the development of cancer biomarkers and potential therapeutic modalities and discuss how they can be engineered and translated into clinical practice.

Heterogeneity of mesenchymal stem cell-derived extracellular vesicles is highly impacted by the tissue/cell source and culture conditions

Extracellular vesicles (EVs) are cell-derived membrane structures exerting major effects in physiological as well as pathological processes by functioning as vehicles for the delivery of biomolecules to their target cells. An increasing number of effects previously attributed to cell-based therapies have been recognized to be actually mediated by EVs derived from the respective cells, suggesting the administration of purified EVs instead of living cells for cell-based therapies. In this review, we focus on the heterogeneity of EVs derived from mesenchymal stem/stromal cells (MSC) and summarize upstream process parameters that crucially affect the resulting therapeutic properties and biological functions. Hereby, we discuss the effects of the cell source, medium composition, 3D culture, bioreactor culture and hypoxia. Furthermore, aspects of the isolation and storage strategies influences EVs are described. Conclusively, optimization of upstream process parameters should focus on controlling MSC-derived EV heterogeneity for specific therapeutic applications.

Graphical Abstract

Synthetic Fibroblasts: Terra Incognita in Cardiac Regeneration

Ischemic heart disease, a major risk factor for myocardial infarction (MI), occurs when the blood vessels supplying oxygen-rich blood to the heart become partially or fully occluded by lipid-rich plaques, resulting in myocardial cell death, remodeling, and scarring. In addition, MI occurs as result of lipid-rich plaque rupture, resulting in thrombosis and vessel occlusion. Cardiac fibroblasts (CFs) and CF-derived growth factors are crucial post-MI in myocardial remodeling. Information regarding the regenerative phenotypes of CFs is scarce; however, regenerative CFs are translationally relevant in myocardial regeneration following MI. The emerging technologies in regenerative cardiology offer cutting-edge translational opportunities, including synthetic cells. In this review, we critically reviewed the current knowledge and the ongoing research efforts on application of synthetic cells for improving cardiac regeneration post-MI. Impact statement Synthetic cells offer tremendous regenerative potential in otherwise deleterious cardiac remodeling postmyocardial infarction. Understanding the role of fibroblasts in cardiac healing and the therapeutic applications of synthetic cells would open a multitude of novel cardiac regenerative approaches. The novel concept of synthetic fibroblasts that emulate native cardiac fibroblasts can provide an effective solution in cardiac healing.

The therapeutical effects of damage-specific stress induced exosomes on the cisplatin nephrotoxicity IN VIVO

Cisplatin is one of the metal containing drugs for the solid cancer treatments. However, its side-effects limit its application in the cancer treatment. Stem cell therapy is a promising treatment for the tissue damage caused by the chemotherapeutic agents, like cisplatin. Exosomes secreted by mesenchymal stem cells (MSCs) could be used for cell-free regenerative treatment, but their potency and reproducibility are questionable. In this study, the microenvironment of the renal tubular epithelial cells was mimicked by coculture of endothelial-, renal proximal tubule epithelial- and fibroblast cells. Cisplatin was applied to this tricell culture model, and the secreted rescue signals were collected and used to induce MSCs. From these stress-induced MSCs, the (stress-induced) exosomes were collected and used for the cell-free therapeutic treatment of cisplatin-treated rats with acute kidney injury. The composition of the stress-induces exosomes was compared with the non-induced exosomes and found that the expression of some critical factors for cell proliferation, repair mechanism and oxidative stress was improved. The cisplatin-damaged renal tissue showed substantial recovery after the treatment with stress-induced exosomes compared to the treatment with non-induced exosomes. Although, the non-induced exosomes showed their activity mostly as cytoprotective, the induced exosomes further involved actively in the tissue regeneration, like MSCs. It was shown that the exosomes could be reprogrammed to improve their therapeutic effect to be used in cell-free regenerative medicine. Further, cisplatin-induced tissue damage in the kidney might be effectively prevented and used for tissue regeneration by use of induced exosomes generated for a particular damage.