Manufactured extracellular vesicles as human therapeutics: challenges, advances, and opportunities

Harnessing exosomes as a platform for drug delivery in breast cancer: A systematic review for in vivo and in vitro studies

Breast cancer remains a significant global health concern, emphasizing the critical need for effective treatment strategies, especially targeted therapies. This systematic review summarizes the findings from in vitro and in vivo studies regarding the therapeutic potential of exosomes as drug delivery platforms in the field of breast cancer treatment. A comprehensive search was conducted across bibliographic datasets, including Web of Science, PubMed, and Scopus, using relevant queries from several related published articles and the Medical Subject Headings Database. Then, all morphological, biomechanical, histopathological, and cellular-molecular outcomes were systematically collected. A total of 30 studies were identified based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. These studies underwent assessment using the Systematic Review Centre for Laboratory Animal Experimentation risk of bias assessment tool. The results indicate that exosomes exhibit promise as effective drug delivery platforms, capable of hindering cancer cell viability, proliferation, migration, and angiogenesis. However, a comprehensive assessment is challenging due to some studies deviating from guidelines and having incomplete methodology. Addressing these, future studies should detail methodologies, optimize dosing, and enhance exosome production. Standardization in reporting, consistent protocols, and exploration of alternative sources are crucial.

Extracellular Vesicles as Next-Generation Diagnostics and Advanced Therapy Medicinal Products

Extracellular vesicles (EVs) hold great promise for clinical application as new diagnostic and therapeutic modalities. This paper describes major GMP-based upstream and downstream manufacturing processes for EV large-scale production, also focusing on post-processing technologies such as surface bioengineering and uploading studies to yield novel EV-based diagnostics and advanced therapy medicinal products. This paper also focuses on the quality, safety, and efficacy issues of the bioengineered EV drug candidates before first-in-human studies. Because clinical trials involving extracellular vesicles are on the global rise, this paper encompasses different clinical studies registered on clinical-trial register platforms, with varying levels of advancement, highlighting the growing interest in EV-related clinical programs. Navigating the regulatory affairs of EVs poses real challenges, and obtaining marketing authorization for EV-based medicines remains complex due to the lack of specific regulatory guidelines for such novel products. This paper discusses the state-of-the-art regulatory knowledge to date on EV-based diagnostics and medicinal products, highlighting further research and global regulatory needs for the safe and reliable implementation of bioengineered EVs as diagnostic and therapeutic tools in clinical settings. Post-marketing pharmacovigilance for EV-based medicinal products is also presented, mainly addressing such topics as risk assessment and risk management.

A novel multi-stage enrichment workflow and comprehensive characterization for HEK293F-derived extracellular vesicles

Extracellular vesicles (EVs) are emerging as a promising drug delivery vehicle as they are biocompatible and capable of targeted delivery. However, clinical translation of EVs remains challenging due to the lack of standardized and scalable manufacturing protocols to consistently isolate small EVs (sEVs) with both high yield and high purity. The heterogenous nature of sEVs leading to unknown composition of biocargos causes further pushback due to safety concerns. In order to address these issues, we developed a robust quality-controlled multi-stage process to produce and isolate sEVs from human embryonic kidney HEK293F cells. We then compared different 2-step and 3-step workflows for eliminating protein impurities and cell-free nucleic acids to meet acceptable limits of regulatory authorities. Our results showed that sEV production was maximized when HEK293F cells were grown at high-density stationary phase in semi-continuous culture. The novel 3-step workflow combining tangential flow filtration, sucrose-cushion ultracentrifugation and bind-elute size-exclusion chromatography outperformed other methods in sEV purity while still preserved high yield and particle integrity. The purified HEK293F-derived sEVs were thoroughly characterized for identity including sub-population analysis, content profiling including proteomics and miRNA sequencing, and demonstrated excellent preclinical safety profile in both in-vitro and in-vivo testing. Our rigorous enrichment workflow and comprehensive characterization will help advance the development of EVs, particularly HEK293F-derived sEVs, to be safe and reliable drug carriers for therapeutic applications.

Artificial Extracellular Vesicles Generated from T Cells Using Different Induction Techniques

Cell therapy is at the forefront of biomedicine in oncology and regenerative medicine. However, there are still significant challenges to their wider clinical application such as limited efficacy, side effects, and logistical difficulties. One of the potential approaches that could overcome these problems is based on extracellular vesicles (EVs) as a cell-free therapy modality. One of the major obstacles in the translation of EVs into practice is their low yield of production, which is insufficient to achieve therapeutic amounts. Here, we evaluated two primary approaches of artificial vesicle induction in primary T cells and the SupT1 cell line-cytochalasin B as a chemical inducer and ultrasonication as a physical inducer. We found that both methods are capable of producing artificial vesicles, but cytochalasin B induction leads to vesicle yield compared to natural secretion, while ultrasonication leads to a three-fold increase in particle yield. Cytochalasin B induces the formation of vesicles full of cytoplasmic compartments without nuclear fraction, while ultrasonication induces the formation of particles rich in membranes and membrane-related components such as CD3 or HLAII proteins. The most effective approach for T-cell induction in terms of the number of vesicles seems to be the combination of anti-CD3/CD28 antibody activation with ultrasonication, which leads to a seven-fold yield increase in particles with a high content of functionally important proteins (CD3, granzyme B, and HLA II).

Immune cell-derived extracellular vesicles for precision therapy of inflammatory-related diseases

Inflammation-related diseases impose a significant global health burden, necessitating urgent exploration of novel treatment modalities for improved clinical outcomes. We begin by discussing the limitations of conventional approaches and underscore the pivotal involvement of immune cells in the inflammatory process. Amidst the rapid growth of immunology, the therapeutic potential of immune cell-derived extracellular vesicles (EVs) has garnered substantial attention due to their capacity to modulate inflammatory response. We provide an in-depth examination of immune cell-derived EVs, delineating their promising roles across diverse disease conditions in both preclinical and clinical settings. Additionally, to direct the development of the next-generation drug delivery systems, we comprehensively investigate the engineered EVs on their advanced isolation methods, cargo loading techniques, and innovative engineering strategies. This review ends with a focus on the prevailing challenges and considerations regarding the clinical translation of EVs in future, emphasizing the need of standardized characterization and scalable production processes. Ultimately, immune cell-derived EVs represent a cutting-edge therapeutic approach and delivery platform, holding immense promise in precision medicine.

Characterization of Nanohybridosomes from Lipids and Spruce Homogenate Containing Extracellular Vesicles

Introduction

Lipid nanovesicles associated with bioactive phytochemicals from spruce needle homogenate (here called nano-sized hybridosomes or nanohybridosomes, NSHs) were considered.

Methods

We formed NSHs by mixing appropriate amounts of lecithin, glycerol and supernatant of isolation of extracellular vesicles from spruce needle homogenate. We visualized NSHs by light microscopy and cryogenic transmission electron microscopy and assessed them by flow cytometry, dynamic light scattering, ultraviolet-visual spectroscopy, interferometric light microscopy and liquid chromatography-mass spectrometry.

Results

We found that the particles consisted of a bilayer membrane and a fluid-like interior. Flow cytometry and interferometric light microscopy measurements showed that the majority of the particles were nano-sized. Dynamic light scattering and interferometric light microscopy measurements agreed well on the average hydrodynamic radius of the particles Rh (between 140 and 180 nm), while the concentrations of the particles were in the range between 1013 and 1014/mL indicating that NSHs present a considerable (more than 25%) of the sample which is much more than the yield of natural extracellular vesicles (EVs) from spruce needle homogenate (estimated less than 1%). Spruce specific lipids and proteins were found in hybridosomes.

Discussion

Simple and low-cost preparation method, non-demanding saving process and efficient formation procedure suggest that large-scale production of NSHs from lipids and spruce needle homogenate is feasible.

Engineered EVs with pathogen proteins: promising vaccine alternatives to LNP-mRNA vaccines

Extracellular vesicles (EVs) are tiny, lipid membrane-bound structures that are released by most cells. They play a vital role in facilitating intercellular communication by delivering bioactive cargoes to recipient cells and triggering cellular as well as biological responses. EVs have enormous potential for therapeutic applications as native or engineered exosomes. Native EVs are naturally released by cells without undergoing any modifications to either the exosomes or the cells that secrete them. In contrast, engineered EVs have been deliberately modified post-secretion or through genetic engineering of the secreting cells to alter their composition. Here we propose that engineered EVs displaying pathogen proteins could serve as promising alternatives to lipid nanoparticle (LNP)-mRNA vaccines. By leveraging their unique characteristics, these engineered EVs have the potential to overcome certain limitations associated with LNP-mRNA vaccines.

Unraveling the surface marker signature of cell-derived vesicles via proteome analysis and nanoparticle flow cytometry

The cell-derived vesicles (CDVs) obtained using a proprietary extrusion process are the foundation of BioDrone platform technology. With superior productivity and versatility, this technology has garnered increasing attention in broad applications, particularly as a drug delivery vehicle. Previously, we showed that CDVs exhibited varying levels of expression for tetraspanin and organelle membrane markers while revealing no discernible differences in physical characteristics compared to naturally produced extracellular vesicles (EVs). To further understand and utilize the therapeutic potentials of CDVs, a more comprehensive study of membrane protein profiles is necessary. In addition, it is crucial to validate that the CDVs produced from extrusion are indeed intact lipid vesicles rather than other impurities. Here, we produced multiple batches of CDVs and EVs from HEK293 cells. CDVs and EVs were subjected to the same purification processes for subsequent proteome and particle analyses. The proteome analyses revealed unique proteome signatures between CDVs, EVs, and parental cells. Extensive proteome analyses identified the nine most prominent membrane markers that are abundant in CDVs compared to cells and EVs. Subsequent western blotting and nanoparticle flow cytometry analyses confirmed that CD63, lysosome-associated membrane glycoprotein 1 (LAMP1), and nicastrin (NCSTN) are highly enriched in CDVs, whereas CD81, CD9, and prostaglandin F2 receptor negative regulator (PTGFRN) are more abundant in EVs. This highlights the unique membrane composition and marker signature of CDVs that are distinct from EVs. Lastly, we demonstrated that more than 90% of the CDVs are genuine lipid vesicles by combining two different classes of vesicle labeling dyes and detergents to disrupt lipid membranes. This indicates that our proprietary extrusion technology is highly compatible with other well-characterized EV production methods. The robust CDV markers identified in this study will also facilitate the engineering of CDVs to achieve enhanced therapeutic effects or tissue-selective cargo delivery.

Quantitative Recoveries of Exosomes and Monoclonal Antibodies from Chinese Hamster Ovary Cell Cultures by Use of a Single, Integrated Two-Dimensional Liquid Chromatography Method

Cultured cell lines are very commonly used for the mass production of therapeutic proteins, such as monoclonal antibodies (mAbs). In particular, Chinese hamster ovary (CHO) cell lines are widely employed due to their high tolerance to variations in experimental conditions and their ability to grow in suspension or serum free media. CHO cell lines are known for their ability to produce high titers of biotherapeutic products such as immunoglobulin G (IgG). An emergent alternative means of treating diseases, such as cancer, is the use of gene therapies, wherein genetic cargo is "packaged" in nanosized vesicular structures, referred to as "vectors". One particularly attractive vector option is extracellular vesicles (EVs), of which exosomes are of greatest interest. While exosomes can be harvested from virtually any human body fluid, bovine milk, or even plants, their production in cell cultures is an attractive commercial approach. In fact, the same CHO cell types employed for mAb production also produce exosomes as a natural byproduct. Here, we describe a single integrated 2D liquid chromatography (2DLC) method for the quantitative recovery of both exosomes and antibodies from a singular sample aliquot. At the heart of the method is the use of polyester capillary-channeled polymer (C-CP) fibers as the first dimension column, wherein exosomes/EVs are captured from the supernatant sample and subsequently determined by multiangle light scattering (MALS), while the mAbs are captured, eluted, and quantified using a protein A-modified C-CP fiber column in the second dimension, all in a 10 min workflow. These efforts demonstrate the versatility of the C-CP fiber phases with the capacity to harvest both forms of therapeutics from a single bioreactor, suggesting an appreciable potential impact in the field of biotherapeutics production.

A clinically relevant large-scale biomanufacturing workflow to produce natural killer cells and natural killer cell-derived extracellular vesicles for cancer immunotherapy

Natural killer cell-derived extracellular vesicles (NK-EVs) have shown promising potential as biotherapeutics for cancer due to their unique attributes as cytotoxic nanovesicles against cancer cells and immune-modulatory activity towards immune cells. However, a biomanufacturing workflow is needed to produce clinical-grade NK-EVs for pre-clinical and clinical applications. This study established a novel biomanufacturing workflow using a closed-loop hollow-fibre bioreactor to continuously produce NK-EVs from the clinically relevant NK92-MI cell line under serum-free, Xeno-free and feeder-free conditions following GMP-compliant conditions. The NK92 cells grown in the bioreactor for three continuous production lots resulted in large quantities of both NK cell and NK-EV biotherapeutics at the end of each production lot (over 109 viable cells and 1013 EVs), while retaining their cytotoxic payload (granzyme B and perforin), pro-inflammatory cytokine (interferon-gamma) content and cytotoxicity against the human leukemic cell line K562 with limited off-target toxicity against healthy human fibroblast cells. This scalable biomanufacturing workflow has the potential to facilitate the clinical translation of adoptive NK cell-based and NK-EV-based immunotherapies for cancer with GMP considerations.

Extracellular vesicles modulate key signalling pathways in refractory wound healing

Chronic wounds are wounds that cannot heal properly due to various factors, such as underlying diseases, infection or reinjury, and improper healing of skin wounds and ulcers can cause a serious economic burden. Numerous studies have shown that extracellular vesicles (EVs) derived from stem/progenitor cells promote wound healing, reduce scar formation and have significant advantages over traditional treatment methods. EVs are membranous particles that carry various bioactive molecules from their cellular origins, such as cytokines, nucleic acids, enzymes, lipids and proteins. EVs can mediate cell-to-cell communication and modulate various physiological processes, such as cell differentiation, angiogenesis, immune response and tissue remodelling. In this review, we summarize the recent advances in EV-based wound healing, focusing on the signalling pathways that are regulated by EVs and their cargos. We discuss how EVs derived from different types of stem/progenitor cells can promote wound healing and reduce scar formation by modulating the Wnt/β-catenin, phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin, vascular endothelial growth factor, transforming growth factor β and JAK-STAT pathways. Moreover, we also highlight the challenges and opportunities for engineering or modifying EVs to enhance their efficacy and specificity for wound healing.

Induced Pluripotent Stem Cell-Derived Extracellular Vesicles Promote Wound Repair in a Diabetic Mouse Model via an Anti-Inflammatory Immunomodulatory Mechanism

Extracellular vesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) have recently been explored in clinical trials for treatment of diseases with complex pathophysiologies. However, production of MSC EVs is currently hampered by donor-specific characteristics and limited ex vivo expansion capabilities before decreased potency, thus restricting their potential as a scalable and reproducible therapeutic. Induced pluripotent stem cells (iPSCs) represent a self-renewing source for obtaining differentiated iPSC-derived MSCs (iMSCs), circumventing both scalability and donor variability concerns for therapeutic EV production. Thus, it is initially sought to evaluate the therapeutic potential of iMSC EVs. Interestingly, while utilizing undifferentiated iPSC EVs as a control, it is found that their vascularization bioactivity is similar and their anti-inflammatory bioactivity is superior to donor-matched iMSC EVs in cell-based assays. To supplement this initial in vitro bioactivity screen, a diabetic wound healing mouse model where both the pro-vascularization and anti-inflammatory activity of these EVs would be beneficial is employed. In this in vivo model, iPSC EVs more effectively mediate inflammation resolution within the wound bed. Combined with the lack of additional differentiation steps required for iMSC generation, these results support the use of undifferentiated iPSCs as a source for therapeutic EV production with respect to both scalability and efficacy.

Extracellular Vesicles in Hepatocellular Carcinoma: Progress and Challenges in the Translation from the Laboratory to Clinic

Extracellular vesicles (EVs) play critical roles in intercellular communication by transporting bioactive cargo to recipient cells. EVs have been implicated in a range of physiological and pathological processes, including tumor progression, metastasis, immune modulation, and drug resistance. The objective of this review is to present a thorough overview of recent studies focusing on EVs in hepatocellular carcinoma (HCC), with an emphasis on their potential utility as diagnostic biomarkers as well as therapeutic agents. Initially, we explore the utility of EVs as diagnostic biomarkers for HCC, followed by a discussion of their potential as carriers of therapeutic payloads. Additionally, we delve into the emerging field of therapeutic EVs for modulating tumor immune responses. Through this review, our ultimate aim is to provide a comprehensive understanding of the opportunities and challenges in the clinical translation of EV research in the domain of HCC.

Selective drug delivery to the retinal cells: Biological barriers and avenues

Retinal drug delivery is a challenging, but important task, because most retinal diseases are still without any proper therapy. Drug delivery to the retina is hampered by the anatomical and physiological barriers resulting in minimal bioavailability after topical ocular and systemic administrations. Intravitreal injections are current method-of-choice in retinal delivery, but these injections show short duration of action for small molecules and low target bioavailability for many protein, gene based drugs and nanomedicines. State-of-art delivery systems are based on prolonged retention, controlled drug release and physical features (e.g. size and charge). However, drug delivery to the retina is not cell-specific and these approaches do not facilitate intracellular delivery of modern biological drugs (e.g. intracellular proteins, RNA based medicines, gene editing). In this focused review we highlight biological factors and mechanisms that form the basis for the selective retinal drug delivery systems in the future. Therefore, we are presenting current knowledge related to retinal membrane transporters, receptors and targeting ligands in relation to nanomedicines, conjugates, extracellular vesicles, and melanin binding. These issues are discussed in the light of retinal structure and cell types as well as future prospects in the field. Unlike in some other fields of targeted drug delivery (e.g. cancer research), selective delivery technologies have been rarely studied, even though cell targeted delivery may be even more feasible after local administration into the eye.

Therapeutic extracellular vesicle production is substantially increased by inhibition of cellular cholesterol biosynthesis

Extracellular vesicles (EVs) are a new therapeutic modality with the promise to treat many diseases through their ability to deliver diverse molecular cargo. As with other emerging modalities transitioning into the industrialization phase, all aspects of the manufacturing process are rich with opportunities to enhance the ability to deliver these medicines to patients. With the goal of improving cell culture EV productivity, we have utilized high throughput siRNA screens to identify the underlying genetic pathways that regulate EV productivity to inform rational host cell line engineering and media development approaches. The screens identified multiple metabolic pathways of potential interest; one of which was validated and shown to be a ready implementable, cost-effective strategy to increase EV titers. We show that both EV volumetric and specific productivity from HEK293 and CHO-S were increased in a dose and cell line-dependent manner up to ninefold when cholesterol synthesis was inhibited by the inclusion of statins in the cell culture media. In addition, we show in response to statin treatment, elevation of EV markers in mesenchymal stem cell (MSC) cell culture media suggesting this approach can also be applicable to MSC EVs. Furthermore, we show that the EVs produced from statin-treated HEK293 cultures are effectively loaded by both endogenous and exogenous loading methods and have equivalent in vitro or in vivo potency relative to EVs from untreated cultures.

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.

Extracellular vesicle-embedded materials

Extracellular vesicles (EVs) are small membrane-bound vesicles released by cells. EVs are emerging as a promising class of therapeutic entity that could be adapted in formulation due to their lack of immunogenicity and targeting capabilities. EVs have been shown to have similar regenerative and therapeutic effects to their parental cells and also have potential in disease diagnosis. To improve the therapeutic potential of EVs, researchers have developed various strategies for modifying them, including genetic engineering and chemical modifications which have been examined to confer target specificity and prevent rapid clearance after systematic injection. Formulation efforts have focused on utilising hydrogel and nano-formulation strategies to increase the persistence of EV localisation in a specific tissue or organ. Researchers have also used biomaterials or bioscaffolds to deliver EVs directly to disease sites and prolong EV release and exposure. This review provides an in-depth examination of the material design of EV delivery systems, highlighting the impact of the material properties on the molecular interactions and the maintenance of EV stability and function. The various characteristics of materials designed to regulate the stability, release rate and biodistribution of EVs are described. Other aspects of material design, including modification methods to improve the targeting of EVs, are also discussed. This review aims to offer an understanding of the strategies for designing EV delivery systems, and how they can be formulated to make the transition from laboratory research to clinical use.

Therapeutic Potential of EVs: Targeting Cardiovascular Diseases

Due to their different biological functions, extracellular vesicles (EVs) have great potential from a therapeutic point of view. They are released by all cell types, carrying and delivering different kinds of biologically functional cargo. Under pathological events, cells can increase their secretion of EVs and can release different amounts of cargo, thus making EVs great biomarkers as indicators of pathological progression. Moreover, EVs are also known to be able to transport and deliver cargo to different recipient cells, having an important role in cellular communication. Interestingly, EVs have recently been explored as biological alternatives for the delivery of therapeutics, being considered natural drug delivery carriers. Because cardiovascular disorders (CVDs) are the leading cause of death worldwide, in this review, we will discuss the up-to-date knowledge regarding the biophysical properties and biological components of EVs, focusing on myocardial infarction, diabetic cardiomyopathy, and sepsis-induced cardiomyopathy, three very different types of CVDs.

Cardiac tissue engineering for myocardial infarction treatment

Myocardial infarction is one of the major causes of morbidity and mortality worldwide. Current treatments can relieve the symptoms of myocardial ischemia but cannot repair the necrotic myocardial tissue. Novel therapeutic strategies based on cellular therapy, extracellular vesicles, non-coding RNAs and growth factors have been designed to restore cardiac function while inducing cardiomyocyte cycle re-entry, ensuring angiogenesis and cardioprotection, and preventing ventricular remodeling. However, they face low stability, cell engraftment issues or enzymatic degradation in vivo, and it is thus essential to combine them with biomaterial-based delivery systems. Microcarriers, nanocarriers, cardiac patches and injectable hydrogels have yielded promising results in preclinical studies, some of which are currently being tested in clinical trials. In this review, we cover the recent advances made in cellular and acellular therapies used for cardiac repair after MI. We present current trends in cardiac tissue engineering related to the use of microcarriers, nanocarriers, cardiac patches and injectable hydrogels as biomaterial-based delivery systems for biologics. Finally, we discuss some of the most crucial aspects that should be addressed in order to advance towards the clinical translation of cardiac tissue engineering approaches.

Induced pluripotent stem cell-derived extracellular vesicles promote wound repair in a diabetic mouse model via an anti-inflammatory immunomodulatory mechanism

Extracellular vesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) have recently been widely explored in clinical trials for treatment of diseases with complex pathophysiology. However, production of MSC EVs is currently hampered by donor-specific characteristics and limited ex vivo expansion capabilities before decreased potency, thus restricting their potential as a scalable and reproducible therapeutic. Induced pluripotent stem cells (iPSCs) represent a self-renewing source for obtaining differentiated iPSC-derived MSCs (iMSCs), circumventing both scalability and donor variability concerns for therapeutic EV production. Thus, we initially sought to evaluate the therapeutic potential of iMSC EVs. Interestingly, while utilizing undifferentiated iPSC EVs as a control, we found that their vascularization bioactivity was similar and their anti-inflammatory bioactivity was superior to donor-matched iMSC EVs in cell-based assays. To supplement this initial in vitro bioactivity screen, we employed a diabetic wound healing mouse model where both the pro-vascularization and anti-inflammatory activity of these EVs would be beneficial. In this in vivo model, iPSC EVs more effectively mediated inflammation resolution within the wound bed. Combined with the lack of additional differentiation steps required for iMSC generation, these results support the use of undifferentiated iPSCs as a source for therapeutic EV production with respect to both scalability and efficacy.

Methodologies for Scalable Production of High-Quality Purified Small Extracellular Vesicles from Conditioned Medium

The development of an extracellular vesicles (EV)-based therapeutic product requires the implementation of reproducible and scalable, purification protocols for clinical-grade EV. Commonly used isolation methods including ultracentrifugation, density gradient centrifugation, size exclusion chromatography, and polymer-based precipitation, faced limitations such as yield efficiency, EV purity, and sample volume. We developed a GMP-compatible method for the scalable production, concentration, and isolation of EV through a strategy involving, tangential flow filtration (TFF). We applied this purification method for the isolation of EV from conditioned medium (CM) of cardiac stromal cells, namely cardiac progenitor cells (CPC) which has been shown to possess potential therapeutical application in heart failure. Conditioned medium collection and EV isolation using TFF demonstrated consistent particle recovery (~10¹³ particle/mL) enrichment of small/medium-EV subfraction (range size 120-140 nm). EV preparations achieved a 97% reduction of major protein-complex contaminant and showed unaltered biological activity. The protocol describes methods to assess EV identity and purity as well as procedures to perform downstream applications including functional potency assay and quality control tests. The large-scale manufacturing of GMP-grade EV represents a versatile protocol that can be easily applied to different cell sources for wide range of therapeutic areas.

Mesenchymal Stem Cell-Derived Extracellular Vesicles: A Potential Therapy for Diabetes Mellitus and Diabetic Complications

As a novel cell-free strategy, mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) inherit the therapeutic potential of donor cells, and are widely used for the treatment of many diseases. Increasing studies have shown that MSC-EVs transfer various bioactive molecules to create a beneficial microenvironment, thus exerting protective roles in diabetic mellitus (DM) and diabetic complications. To overcome the limitations of natural MSC-EVs such as heterogeneity and insufficient function, several modification methods have been established for constructing engineered MSC-EVs with elevated repairing efficiency. In this review, the PubMed library was searched from inception to August 2022, using a combination of Medical Subject Headings (MeSH) and keywords related to MSC-EVs, DM, and diabetic complications. We provide an overview of the major characteristics of MSC-EVs and summarize the recent advances of MSC-EV-based therapy for hyperglycemia-induced tissue damage with an emphasis on MSC-EV-mediated delivery of functional components. Moreover, the potential applications of engineered MSC-EVs in DM-related diseases therapy are discussed by presenting examples, and the opportunities and challenges for the clinical translation of MSC-EVs, especially engineered MSC-EVs, are evaluated.