Current status and outlook of advances in exosome isolation

Hydrogel-exosome system in tissue engineering: A promising therapeutic strategy

Characterized by their pivotal roles in cell-to-cell communication, cell proliferation, and immune regulation during tissue repair, exosomes have emerged as a promising avenue for "cell-free therapy" in clinical applications. Hydrogels, possessing commendable biocompatibility, degradability, adjustability, and physical properties akin to biological tissues, have also found extensive utility in tissue engineering and regenerative repair. The synergistic combination of exosomes and hydrogels holds the potential not only to enhance the efficiency of exosomes but also to collaboratively advance the tissue repair process. This review has summarized the advancements made over the past decade in the research of hydrogel-exosome systems for regenerating various tissues including skin, bone, cartilage, nerves and tendons, with a focus on the methods for encapsulating and releasing exosomes within the hydrogels. It has also critically examined the gaps and limitations in current research, whilst proposed future directions and potential applications of this innovative approach.

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

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

Comparing the Proteomic Profiles of Extracellular Vesicles Isolated using Different Methods from Long-term Stored Plasma Samples

BACKGROUND

The lack of standardized protocols for isolating extracellular vesicles (EVs), especially from biobank-stored blood plasma, translates to limitations for the study of new biomarkers. This study examines whether a combination of current isolation methods could enhance the specificity and purity of isolated EVs for diagnosis and personalized medicine purposes.

RESULTS

EVs were isolated from healthy human plasma stored for one year by ultracentrifugation (UC), size exclusion chromatography (SEC), or SEC and UC combined (SEC + UC). The EV isolates were then characterized by transmission electron microscopy imaging, nanoparticle tracking analysis (NTA) and western blotting. Proteomic procedures were used to analyze protein contents. The presence of EV markers in all isolates was confirmed by western blotting yet this analysis revealed higher albumin expression in EVs-UC, suggesting plasma protein contamination. Proteomic analysis identified 542 proteins, SEC + UC yielding the most complex proteome at 364 proteins. Through gene ontology enrichment, we observed differences in the cellular components of EVs and plasma in that SEC + UC isolates featured higher proportions of EV proteins than those derived from the other two methods. Analysis of proteins unique to each isolation method served to identify 181 unique proteins for the combined approach, including those normally appearing in low concentrations in plasma. This indicates that with this combined method, it is possible to detect less abundant plasma proteins by proteomics in the resultant isolates.

CONCLUSIONS

Our findings reveal that the SEC + UC approach yields highly pure and diverse EVs suitable for comprehensive proteomic analysis with applications for the detection of new biomarkers in biobank-stored plasma samples.

Advances in Nanoplasmonic Biosensors: Optimizing Performance for Exosome Detection Applications

The development of sensitive and specific exosome detection tools is essential because they are believed to provide specific information that is important for early detection, screening, diagnosis, and monitoring of cancer. Among the many detection tools, surface-plasmon resonance (SPR) biosensors are analytical devices that offer advantages in sensitivity and detection speed, thereby making the sample-analysis process faster and more accurate. In addition, the penetration depth of the SPR biosensor, which is <300 nm, is comparable to the size of the exosome, making the SPR biosensor ideal for use in exosome research. On the other hand, another type of nanoplasmonic sensor, namely a localized surface-plasmon resonance (LSPR) biosensor, has a shorter penetration depth of around 6 nm. Structural optimization through the addition of supporting layers and gap control between particles is needed to strengthen the surface-plasmon field. This paper summarizes the progress of the development of SPR and LSPR biosensors for detecting exosomes. Techniques in signal amplification from two sensors will be discussed. There are three main parts to this paper. The first two parts will focus on reviewing the working principles of each sensor and introducing several methods that can be used to isolate exosomes. This article will close by explaining the various sensor systems that have been developed and the optimizations carried out to obtain sensors with better performance. To illustrate the performance improvements in each sensor system discussed, the parameters highlighted include the detection limit, dynamic range, and sensitivity.

Potential in exosome-based targeted nano-drugs and delivery vehicles for posterior ocular disease treatment: from barriers to therapeutic application

Posterior ocular disease, a disease that accounts for 55% of all ocular diseases, can contribute to permanent vision loss if left without treatment. Due to the special structure of the eye, various obstacles make it difficult for drugs to reach lesions in the posterior ocular segment. Therefore, the development of highly permeable targeted drugs and delivery systems is particularly important. Exosomes are a class of extracellular vesicles at 30-150 nm, which are secreted by various cells, tissues, and body fluids. They carry various signaling molecules, thus endowing them with certain physiological functions. In this review, we describe the ocular barriers and the biogenesis, isolation, and engineering of exosomes, as exosomes not only have pharmacological effects but also are good nanocarriers with targeted properties. Moreover, their biocompatibility and immunogenicity are better than synthetic nanocarriers. Most importantly, they may have the ability to pass through the blood-eye barrier. Thus, they may be developed as both targeted nano-drugs and nano-delivery vehicles for the treatment of posterior ocular diseases. We focus on the current status and potential application of exosomes as targeted nano-drugs and nano-delivery vehicles in posterior ocular diseases.

Extracellular vesicles in nanomedicine and regenerative medicine: A review over the last decade

Small extracellular vesicles (sEVs) are known to be secreted by a vast majority of cells. These sEVs, specifically exosomes, induce specific cell-to-cell interactions and can activate signaling pathways in recipient cells through fusion or interaction. These nanovesicles possess several desirable properties, making them ideal for regenerative medicine and nanomedicine applications. These properties include exceptional stability, biocompatibility, wide biodistribution, and minimal immunogenicity. However, the practical utilization of sEVs, particularly in clinical settings and at a large scale, is hindered by the expensive procedures required for their isolation, limited circulation lifetime, and suboptimal targeting capacity. Despite these challenges, sEVs have demonstrated a remarkable ability to accommodate various cargoes and have found extensive applications in the biomedical sciences. To overcome the limitations of sEVs and broaden their potential applications, researchers should strive to deepen their understanding of current isolation, loading, and characterization techniques. Additionally, acquiring fundamental knowledge about sEVs origins and employing state-of-the-art methodologies in nanomedicine and regenerative medicine can expand the sEVs research scope. This review provides a comprehensive overview of state-of-the-art exosome-based strategies in diverse nanomedicine domains, encompassing cancer therapy, immunotherapy, and biomarker applications. Furthermore, we emphasize the immense potential of exosomes in regenerative medicine.

Immune capture and protein profiling of small extracellular vesicles from human plasma

Extracellular vesicles (EVs), the key players in inter-cellular communication, are produced by all cell types and are present in all body fluids. Analysis of the proteome content is an important approach in structural and functional studies of these vesicles. EVs circulating in human plasma are heterogeneous in size, cellular origin, and functions. This heterogeneity and the potential presence of contamination with plasma components such as lipoprotein particles and soluble plasma proteins represent a challenge in profiling the proteome of EV subsets by mass spectrometry. An immunocapture strategy prior to mass spectrometry may be used to isolate a homogeneous subpopulation of small EVs (sEV) with a specific endocytic origin from plasma or other biofluids. Immunocapture selectively separates EV subpopulations in biofluids based on the presence of a unique protein carried on the vesicle surface. The advantages and disadvantages of EV immune capture as a preparative step for mass spectrometry are discussed.

A pipeline for the development and analysis of extracellular vesicle-based transcriptomic biomarkers in molecular diagnostics

Extracellular vesicles are shed by every cell type and can be found in any biofluid. They contain different molecules that can be utilized as biomarkers, including several RNA species which they protect from degradation. Here, we present a pipeline for the development and analysis of extracellular vesicle-associated transcriptomic biomarkers that our group has successfully applied multiple times. We highlight the key steps of the pipeline and give particular emphasis to the necessary quality control checkpoints, which are linked to numerous available guidelines that should be considered along the workflow. Our pipeline starts with patient recruitment and continues with blood sampling and processing. The purification and characterization of extracellular vesicles is explained in detail, as well as the isolation and quality control of extracellular vesicle-associated RNA. We point out the possible pitfalls during library preparation and RNA sequencing and present multiple bioinformatic tools to pinpoint biomarker signature candidates from the sequencing data. Finally, considerations and pitfalls during the validation of the biomarker signature using RT-qPCR will be elaborated.

The future of diabetic wound healing: unveiling the potential of mesenchymal stem cell and exosomes therapy

Diabetes mellitus (DM) is a significant public health problem and is one of the most challenging medical conditions worldwide. It is the severe complications that make this disease more intricate. A diabetic wound is one of these complications. Patients with diabetes are at higher risk of developing diabetic foot ulcers (DFU). Due to the ineffectiveness of Conventional treatments, growth in limb amputation, morbidity, and mortality have been recognized, which indicates the need for additional treatment. Mesenchymal stem cells (MSCs) can significantly improve wound healing. However, there are some risks related to stem cell therapy. Exosome therapy is a new treatment option for diabetic wounds that has shown promising results. However, an even more advanced form called cell-free therapy using exosomes has emerged. This upgraded version of stem cell therapy offers improved efficacy and eliminates the risk of cancer progression. Exosome therapy promotes wound healing from multiple angles, unlike traditional methods that primarily rely on the body's self-healing ability and only provide wound protection. Therefore, exosome therapy has the potential to replace conventional treatments effectively. However, further research is necessary to distinguish the optimal type of stem cells for therapy, ensure their safety, establish appropriate dosing, and identify the best management trail. The present study focused on the current literature on diabetic wound ulcers, their treatment, and mesenchymal stem cell and exosome therapy potential in DFU.

Spinning with exosomes: electrospun nanofibers for efficient targeting of stem cell-derived exosomes in tissue regeneration

Electrospinning technique converts polymeric solutions into nanoscale fibers using an electric field and can be used for various biomedical and clinical applications. Extracellular vesicles (EVs) are cell-derived small lipid vesicles enriched with biological cargo (proteins and nucleic acids) potential therapeutic applications. In this review, we discuss extending the scope of electrospinning by incorporating stem cell-derived EVs, particularly exosomes, into nanofibers for their effective delivery to target tissues. The parameters used during the electrospinning of biopolymers limit the stability and functional properties of cellular products. However, with careful consideration of process requirements, these can significantly improve stability, leading to longevity, effectiveness, and sustained and localized release. Electrospun nanofibers are known to encapsulate or surface-adsorb biological payloads such as therapeutic EVs, proteins, enzymes, and nucleic acids. Small EVs, specifically exosomes, have recently attracted the attention of researchers working on regeneration and tissue engineering because of their broad distribution and enormous potential as therapeutic agents. This review focuses on current developments in nanofibers for delivering therapeutic cargo molecules, with a special emphasis on exosomes. It also suggests prospective approaches that can be adapted to safely combine these two nanoscale systems and exponentially enhance their benefits in tissue engineering, medical device coating, and drug delivery applications.

Analysis and Characterization of the Extracellular Vesicles Released in Non-Cancer Diseases Using Matrix-Assisted Laser Desorption Ionization/Mass Spectrometry

The extracellular vesicles (EVs) released by cells play a crucial role in intercellular communications and interactions. The direct shedding of EVs from the plasma membrane represents a fundamental pathway for the transfer of properties and information between cells. These vesicles are classified based on their origin, biogenesis, size, content, surface markers, and functional features, encompassing a variety of bioactive molecules that reflect the physiological state and cell type of origin. Such molecules include lipids, nucleic acids, and proteins. Research efforts aimed at comprehending EVs, including the development of strategies for their isolation, purification, and characterization, have led to the discovery of new biomarkers. These biomarkers are proving invaluable for diagnosing diseases, monitoring disease progression, understanding treatment responses, especially in oncology, and addressing metabolic, neurological, infectious disorders, as well as advancing vaccine development. Matrix-Assisted Laser Desorption Ionization (MALDI)/Mass Spectrometry (MS) stands out as a leading tool for the analysis and characterization of EVs and their cargo. This technique offers inherent advantages such as a high throughput, minimal sample consumption, rapid and cost-effective analysis, and user-friendly operation. This review is mainly focused on the primary applications of MALDI-time-of-flight (TOF)/MS in the analysis and characterization of extracellular vesicles associated with non-cancerous diseases and pathogens that infect humans, animals, and plants.

Emerging Strategies to Overcome Current CAR-T Therapy Dilemmas - Exosomes Derived from CAR-T Cells

Adoptive T cells immunotherapy, specifically chimeric antigen receptor T cells (CAR-T), has shown promising therapeutic efficacy in the treatment of hematologic malignancies. As extensive research on CAR-T therapies has been conducted, various challenges have emerged that significantly hampered their clinical application, including tumor recurrence, CAR-T cell exhaustion, and cytokine release syndrome (CRS). To overcome the hurdles of CAR-T therapy in clinical treatment, cell-free emerging therapies based on exosomes derived from CAR-T cells have been developed as an effective and promising alternative approach. In this review, we present CAR-T cell-based therapies for the treatment of tumors, including the features and benefits of CAR-T therapies, the limitations that exist in this field, and the measures taken to overcome them. Furthermore, we discuss the notable benefits of utilizing exosomes released from CAR-T cells in tumor treatment and anticipate potential issues in clinical trials. Lastly, drawing from previous research on exosomes from CAR-T cells and the characteristics of exosomes, we propose strategies to overcome these restrictions. Additionally, the review discusses the plight in large-scale preparation of exosome and provides potential solutions for future clinical applications.

Circulating exosome-mediated AMPKα-SIRT1 pathway regulates lipid metabolism disorders in calf hepatocytes

Subclinical ketosis (SCK) in dairy cows is often misdiagnosed because it lacks clinical signs and detection indicators. However, it is highly prevalent and may transform into clinical ketosis if not treated promptly. Due to the negative energy balance, a large amount of fat is mobilized, producing NEFA that exceeds the upper limit of liver processing, which in turn leads to the disturbance of liver lipid metabolism. The silent information regulator 1 (SIRT1) is closely related to hepatic lipid metabolism disorders. Exosomes as signal transmitters, also play a role in the circulatory system. We hypothesize that the circulating exosome-mediated adenosine 5'-monophosphate (AMP)-activated protein kinase alpha (AMPKα)-SIRT1 pathway regulates lipid metabolism disorders in SCK cows. We extracted the exosomes required for the experiment from the peripheral circulating blood of non-ketotic (NK) and SCK cows. We investigated the effect of circulating exosomes on the expression levels of mRNA and protein of the AMPKα-SIRT1 pathway in non-esterified fatty acid (NEFA)-induced dairy cow primary hepatocytes using in vitro cell experiments. The results showed that circulating exosomes increased the expression levels of Lipolysis-related genes and proteins (AMPKα, SIRT1, and PGC-1α) in hepatocytes treated with 1.2 mM NEFA, and inhibited the expression of lipid synthesis-related genes and protein (SREBP-1C). The regulation of exosomes on lipid metabolism disorders caused by 1.2 mM NEFA treatment showed the same trend as for SIRT1-overexpressing adenovirus. The added exosomes could regulate NEFA-induced lipid metabolism in hepatocytes by mediating the AMPKα-SIRT1 pathway, consistent with the effect of transfected SIRT1 adenovirus.

Exosomes as Emerging Regulators of Immune Responses in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by high blood glucose levels resulting from insulin resistance and impaired insulin secretion. Immune dysregulation-mediated chronic low-grade inflammation is a critical factor that poses a significant risk to the metabolic disorders of T2DM and its related complications. Exosomes, as small extracellular vesicles secreted by various cells, have emerged as essential regulators of intercellular communication and immune regulation. In this review, we summarize the current understanding of the role of exosomes derived from immune and nonimmune cells in modulating immune responses in T2DM by regulating immune cell functions and cytokine production. More importantly, we suggest potential strategies for the clinical applications of exosomes in T2DM management, including biomarkers for disease diagnosis and monitoring, exosome-based therapies for drug delivery vehicles, and targeted therapy for exosomes.

Exosome-based delivery strategies for tumor therapy: an update on modification, loading, and clinical application

Malignancy is a major public health problem and among the leading lethal diseases worldwide. Although the current tumor treatment methods have therapeutic effect to a certain extent, they still have some shortcomings such as poor water solubility, short half-life, local and systemic toxicity. Therefore, how to deliver therapeutic agent so as to realize safe and effective anti-tumor therapy become a problem urgently to be solved in this field. As a medium of information exchange and material transport between cells, exosomes are considered to be a promising drug delivery carrier due to their nano-size, good biocompatibility, natural targeting, and easy modification. In this review, we summarize recent advances in the isolation, identification, drug loading, and modification of exosomes as drug carriers for tumor therapy alongside their application in tumor therapy. Basic knowledge of exosomes, such as their biogenesis, sources, and characterization methods, is also introduced herein. In addition, challenges related to the use of exosomes as drug delivery vehicles are discussed, along with future trends. This review provides a scientific basis for the application of exosome delivery systems in oncological therapy.

Exosomes and exosome composite scaffolds in periodontal tissue engineering

Promoting complete periodontal regeneration of damaged periodontal tissues, including dental cementum, periodontal ligament, and alveolar bone, is one of the challenges in the treatment of periodontitis. Therefore, it is urgent to explore new treatment strategies for periodontitis. Exosomes generated from stem cells are now a promising alternative to stem cell therapy, with therapeutic results comparable to those of their blast cells. It has great potential in regulating immune function, inflammation, microbiota, and tissue regeneration and has shown good effects in periodontal tissue regeneration. In addition, periodontal tissue engineering combines exosomes with biomaterial scaffolds to maximize the therapeutic advantages of exosomes. Therefore, this article reviews the progress, challenges, and prospects of exosome and exosome-loaded composite scaffolds in periodontal regeneration.

Engineering Neurotoxin-Functionalized Exosomes for Targeted Delivery to the Peripheral Nervous System

The administration of therapeutics to peripheral nerve tissue is challenging due to the complexities of peripheral neuroanatomy and the limitations imposed by the blood-nerve barrier (BNB). Therefore, there is a pressing need to enhance delivery effectiveness and implement targeted delivery methods. Recently, erythrocyte-derived exosomes (Exos) have gained widespread attention as biocompatible vehicles for therapeutics in clinical applications. However, engineering targeted Exos for the peripheral nervous system (PNS) is still challenging. This study aims to develop a targeted Exo delivery system specifically designed for presynaptic terminals of peripheral nerve tissue. The clostridium neurotoxin, tetanus toxin-C fragment (TTC), was tethered to the surface of red blood cell (RBC)-derived Exos via a facile and efficient bio-orthogonal click chemistry method without a catalyst. Additionally, Cyanine5 (Cy5), a reactive fluorescent tag, was also conjugated to track Exo movement in both in vitro and in vivo models. Subsequently, Neuro-2a, a mouse neuronal cell line, was treated with dye-labeled Exos with/without TTC in vitro, and the results indicated that TTC-Exos exhibited more efficient accumulation along the soma and axonal circumference, compared to their unmodified counterparts. Further investigation, using a mouse model, revealed that within 72 h of intramuscular administration, engineered TTC-Exos were successfully transported into the neuromuscular junction and sciatic nerve tissues. These results indicated that TTC played a crucial role in the Exo delivery system, improving the affinity to peripheral nerves. These promising results underscore the potential of using targeted Exo carriers to deliver therapeutics for treating peripheral neuropathies.

Gastric cancer and mesenchymal stem cell-derived exosomes: from pro-tumorigenic effects to anti-cancer vehicles

Gastric cancer (GC) is one of the most prevalent malignancies in the world, with a high mortality rate in both women and men. Conventional treatments, like chemotherapy, radiotherapy and surgery, are facing some drawbacks like acquired drug resistance and various side effects, leading to cancer recurrence and increased morbidity; thus, development of novel approaches in targeted therapy would be very beneficial. Exosomes, extracellular vesicles with a size distribution of sub-150 nm, interplay in physiological and pathophysiological cell-cell communications and can pave the way for targeted cancer therapy. Accumulating pieces of evidence have indicated that exosomes derived from mesenchymal stem cells (MSC-EXs) can act as a double-edged sword in some cancers. The purpose of this review is to assess the differences between stem cell therapy and exosome therapy. Moreover, our aim is to demonstrate how naïve MSCs transform into GC-MSCs in the tumor microenvironment. Additionally, the tumorigenic and anti-proliferation effects of MSC-EXs derived from different origins were investigated. Finally, we suggest potential modifications and combination options that involve utilizing MSC-EXs from the foreskin and umbilical cord as promising sources to enhance the efficacy of gastric cancer treatment. This approach is presented in contrast to bone marrow cells, which are more heterogeneous, age-related, and are also easily affected by the patient's circulation system.

The emerging role of exosomes in communication between the periphery and the central nervous system

Exosomes, membrane-enclosed vesicles, are secreted by all types of cells. Exosomes can transport various molecules, including proteins, lipids, functional mRNAs, and microRNAs, and can be circulated to various recipient cells, leading to the production of local paracrine or distal systemic effects. Numerous studies have proved that exosomes can pass through the blood-brain barrier, thus, enabling the transfer of peripheral substances into the central nervous system (CNS). Consequently, exosomes may be a vital factor in the exchange of information between the periphery and CNS. This review will discuss the structure, biogenesis, and functional characterization of exosomes and summarize the role of peripheral exosomes deriving from tissues like the lung, gut, skeletal muscle, and various stem cell types in communicating with the CNS and influencing the brain's function. Then, we further discuss the potential therapeutic effects of exosomes in brain diseases and the clinical opportunities and challenges. Gaining a clearer insight into the communication between the CNS and the external areas of the body will help us to ascertain the role of the peripheral elements in the maintenance of brain health and illness and will facilitate the design of minimally invasive techniques for diagnosing and treating brain diseases.

Exosomal miRNAs as Biomarkers of Ischemic Stroke

Exosomes are small lipid bilayer membrane particles released from all living cells into the extracellular environment. They carry several molecules and have a critical role in cell-cell communication under physiological and pathological conditions. In recent decades, exosomes, and especially their cargo, have emerged as a promising tool for several clinical conditions. However, the literature has become increasingly unambiguous in defining the role of exosomes in chronic cerebrovascular diseases. Because they can pass through the blood-brain barrier, they have great potential to reflect intracerebral changes. They can, thus, provide valuable insight into the mechanisms of central nervous system diseases. The purpose of this review is to describe the literature on the role of exosomal miRNA, which represents the most widely investigated exosomal biomarker, in strokes. First, we provide an overview of exosomes, from biology to isolation and characterization. Then, we describe the relationship between exosomes and stroke pathogenesis. Finally, we summarize the human studies evaluating exosomal miRNA biomarkers of stroke. Although the collective literature supports the potential use of exosomal miRNA as biomarkers of ischemic stroke, there are still several limitations hampering their introduction into clinical practice.

A comparison of size exclusion chromatography-based tandem strategies for plasma exosome enrichment and proteomic analysis

Proteomic analysis of exosomes from human plasma faces a tremendous challenge mainly due to the low abundance of the exosome itself and the complexity of the plasma matrix. Therefore, enrichment of exosomes from human plasma is an essential and indispensable step for large scale and in depth proteomic analysis. Size exclusion chromatography (SEC) is one of the most extensively used methods for exosome isolation from human plasma and many SEC-based tandem methods were established in order to increase the purity of the enriched exosomes and thus the accuracy of the proteomic analysis. To compare the advantages and disadvantages of the different isolation methods and subsequently to promote the establishment of a standardized method for plasma proteomic research, the capacities of the direct SEC method, the combination of SEC with ultracentrifugation (SEC-UC), ultrafiltration (SEC-UF), and titanium dioxide microspheres (SEC-TiO2) were systematically evaluated for exosome isolation from human plasma and thus proteomic analysis. The results demonstrated that the SEC-based tandem methods were superior to the direct SEC method in the purity of exosomes isolated from human plasma. Additionally, the SEC-UC method possessed the highest number of the total identified proteins and the overlapped proteins with the top 100 exosome markers in comparison with the other methods. The SEC-TiO2 method displayed the biggest capacity for plasma protein deleting. We expect that the research will have more beneficial values in the field of exosome research.

Dual impacts of mesenchymal stem cell-derived exosomes on cancer cells: unravelling complex interactions

Mesenchymal stem cells (MSCs) are multipotent, self-renewing stromal cells found in a variety of adult tissues. MSCs possess a remarkable ability to migrate towards tumor sites, known as homing. This homing process is mediated by various factors, including chemokines, growth factors, and extracellular matrix components present in the tumor microenvironment. MSCs release extracellular vesicles known as exosomes (MSC-Exos), which have been suggested to serve a key role in mediating a wide variety of MSC activities. Through cell-cell communication, MSC-Exos have been shown to alter recipient cell phenotype or function and play as a novel cell-free alternative for MSC-based cell therapy. However, MSC recruitment to tumors allows for their interaction with cancer cells and subsequent regulation of tumor behavior. MSC-Exos act as tumor niche modulators via transferring exosomal contents, such as specific proteins or genetic materials, to the nearby cancer cells, leading to either promotion or suppression of tumorigenesis, angiogenesis, and metastasis, depending on the specific microenvironmental cues and recipient cell characteristics. Consequently, there is still a debate about the precise relationship between tumor cells and MSC-Exos, and it is unclear how MSC-Exos impacts tumor cells. Although the dysregulation of miRNAs is caused by the progression of cancer, they also play a direct role in either promoting or inhibiting tumor growth as they act as either oncogenes or tumor suppressors. The utilization of MSC-Exos may prove to be an effective method for restoring miRNA as a means of treating cancer. This review aimed to present the existing understanding of the impact that MSC-Exos could have on cancer. To begin with, we presented a brief explanation of exosomes, MSCs, and MSC-Exos. Following this, we delved into the impact of MSC-Exos on cancer growth, EMT, metastasis, angiogenesis, resistance to chemotherapy and radiotherapy, and modulation of the immune system. Opposing effects of mesenchymal stem cells-derived exosomes on cancer cells.

Tumor-derived systems as novel biomedical tools-turning the enemy into an ally

Cancer is a complex illness that presents significant challenges in its understanding and treatment. The classic definition, "a group of diseases characterized by the uncontrolled growth and spread of abnormal cells in the body," fails to convey the intricate interaction between the many entities involved in cancer. Recent advancements in the field of cancer research have shed light on the role played by individual cancer cells and the tumor microenvironment as a whole in tumor development and progression. This breakthrough enables the utilization of the tumor and its components as biological tools, opening new possibilities. This article delves deeply into the concept of "tumor-derived systems", an umbrella term for tools sourced from the tumor that aid in combatting it. It includes cancer cell membrane-coated nanoparticles (for tumor theranostics), extracellular vesicles (for tumor diagnosis/therapy), tumor cell lysates (for cancer vaccine development), and engineered cancer cells/organoids (for cancer research). This review seeks to offer a complete overview of the tumor-derived materials that are utilized in cancer research, as well as their current stages of development and implementation. It is aimed primarily at researchers working at the interface of cancer biology and biomedical engineering, and it provides vital insights into this fast-growing topic.

Exploring the Versatility of Exosomes: A Review on Isolation, Characterization, Detection Methods, and Diverse Applications

Extracellular vesicles (EVs) are crucial mediators of intercellular communication and can be classified based on their physical properties, biomolecular structure, and origin. Among EVs, exosomes have garnered significant attention due to their potential as therapeutic and diagnostic tools. Exosomes are released via fusion of multivesicular bodies on plasma membranes and can be isolated from various biofluids using methods such as differential ultracentrifugation, immune affinity capture, ultrafiltration, and size exclusion chromatography. Herein, an overview of different techniques for exosome characterization and isolation, as well as the diverse applications of exosome detection, including their potential use in drug delivery and disease diagnosis, is provided. Additionally, we discuss the emerging field of exosome detection by sensors, which offers an up-and-coming avenue for point-of-care diagnostic tools development. Overall, this review aims to provide a exhaustive and up-to-date summary of the current state of exosome research.

Engineered exosomes for tissue regeneration: from biouptake, functionalization and biosafety to applications

Exosomes are increasingly recognized as important effector molecules that regulate intercellular signaling pathways. Notably, certain types of exosomes can induce therapeutic responses, including cell proliferation, angiogenesis, and tissue repair. The use of exosomes in therapy is a hot spot in current research, especially in regenerative medicine. Despite the therapeutic potential, problems have hindered their success in clinical applications. These shortcomings include low concentration, poor targeting and limited loading capability. To fully realize their therapeutic potential, certain modifications are needed in native exosomes. In the present review, we summarize the exosome modification and functionalization strategies. In addition, we provide an overview of potential clinical applications and highlight the issues associated with the biosafety and biocompatibility of engineered exosomes in applications.

Hypoxic regulation of extracellular vesicles: Implications for cancer therapy

Extracellular vesicles (EVs) play a pivotal role in intercellular communication and have been implicated in cancer progression. Hypoxia, a pervasive hallmark of cancer, is known to regulate EV biogenesis and function. Hypoxic EVs contain a specific set of proteins, nucleic acids, lipids, and metabolites, capable of reprogramming the biology and fate of recipient cells. Enhancing the intrinsic therapeutic efficacy of EVs can be achieved by strategically modifying their structure and contents. Moreover, the use of EVs as drug delivery vehicles holds great promise for cancer treatment. However, various hurdles must be overcome to enable their clinical application as cancer therapeutics. In this review, we aim to discuss the current knowledge on the hypoxic regulation of EVs. Additionally, we will describe the underlying mechanisms by which EVs contribute to cancer progression in hypoxia and outline the progress and limitations of hypoxia-related EV therapeutics for cancer.

Comparison Study of Small Extracellular Vesicle Isolation Methods for Profiling Protein Biomarkers in Breast Cancer Liquid Biopsies

Small extracellular vesicles (sEVs) are an important intercellular communicator, participating in all stages of cancer metastasis, immunity, and therapeutic resistance. Therefore, protein cargoes within sEVs are considered as a superior source for breast cancer (BC) biomarker discovery. Our study aimed to optimise the approach for sEV isolation and sEV proteomic analysis to identify potential sEV protein biomarkers for BC diagnosis. sEVs derived from BC cell lines, BC patients' plasma, and non-cancer controls were isolated using ultracentrifugation (UC), a Total Exosome Isolation kit (TEI), and a combined approach named UCT. In BC cell lines, the UC isolates showed a higher sEV purity and marker expression, as well as a higher number of sEV proteins. In BC plasma samples, the UCT isolates showed the highest proportion of sEV-related proteins and the lowest percentage of lipoprotein-related proteins. Our data suggest that the assessment of both the quantity and quality of sEV isolation methods is important in selecting the optimal approach for the specific sEV research purpose, depending on the sample types and downstream analysis.

Exosomes in Cancer Progression and Therapy Resistance: Molecular Insights and Therapeutic Opportunities

The development of therapy resistance still represents a major hurdle in treating cancers, leading to impaired treatment success and increased patient morbidity. The establishment of minimally invasive liquid biopsies is a promising approach to improving the early diagnosis, as well as therapy monitoring, of solid tumors. Because of their manifold functions in the tumor microenvironment, tumor-associated small extracellular vesicles, referred to as exosomes, have become a subject of intense research. Besides their important roles in cancer progression, metastasis, and the immune response, it has been proposed that exosomes also contribute to the acquisition and transfer of therapy resistance, mainly by delivering functional proteins and RNAs, as well as facilitating the export of active drugs or functioning as extracellular decoys. Extensive research has focused on understanding the molecular mechanisms underlying the occurrence of resistance and translating these into strategies for early detection. With this review, we want to provide an overview of the current knowledge about the (patho-)biology of exosomes, as well as state-of-the-art methods of isolation and analysis. Furthermore, we highlight the role of exosomes in tumorigenesis and cancer treatment, where they can function as therapeutic agents, biomarkers, and/or targets. By focusing on their roles in therapy resistance, we will reveal new paths of exploiting exosomes for cancer diagnosis and treatment.

Application of exosome engineering modification in targeted delivery of therapeutic drugs

Cancer is the leading cause of premature death in humans. Scientists have developed several therapeutic drugs for cancer treatment. However, drug delivery faces many problems. First, traditional drugs do not target tumors and are prone to causing significant toxic side effects. Second, suitable drug carriers are essential for improving drug delivery to tumors or circulating cancer cells. Exosomes are natural extracellular vesicles with low immunogenicity and prolonged blood circulation in vivo. These characteristics render exosomes ideal drug carriers. This review highlights the properties of exosomes and mechanisms of exosome biogenesis. It also summarizes the engineering modification methods for enhancing exosome yield, targeting, and drug-loading capacity.

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.

Crosstalk between colorectal cancer cells and cancer-associated fibroblasts in the tumor microenvironment mediated by exosomal noncoding RNAs

Colorectal cancer (CRC) is a common malignant tumor of the digestive system, and its morbidity rates are increasing worldwide. Cancer-associated fibroblasts (CAFs), as part of the tumor microenvironment (TME), are not only closely linked to normal fibroblasts, but also can secrete a variety of substances (including exosomes) to participate in the regulation of the TME. Exosomes can play a key role in intercellular communication by delivering intracellular signaling substances (e.g., proteins, nucleic acids, non-coding RNAs), and an increasing number of studies have shown that non-coding RNAs of exosomal origin from CAFs are not only closely associated with the formation of the CRC microenvironment, but also increase the ability of CRC to grow in metastasis, mediate tumor immunosuppression, and are involved in the mechanism of drug resistance in CRC patients receiving. It is also involved in the mechanism of drug resistance after radiotherapy in CRC patients. In this paper, we review the current status and progress of research on CAFs-derived exosomal non-coding RNAs in CRC.

Digging the intercellular crosstalk via extracellular vesicles: May exosomes be the drug delivery solution for target glioblastoma?

Glioblastoma (GBM) is an adult's most aggressive brain tumor. The advances in molecular pathology and cell signaling pathways have deepened researchers' understanding of intercellular communication mechanisms that can induce tumor progression, namely the release of extracellular vesicles. Exosomes are small extracellular vesicles in various biological fluids released by almost all cells, thus carrying various biomolecules specific to their parental cell. Several pieces of evidence indicate that exosomes mediate intercellular communication in the tumor microenvironment and cross the blood-brain barrier (BBB), valuable tools for diagnostic and therapeutic applications under the scope of brain diseases such as brain tumors. This review aims to resume the several biological characteristics and the interplay between glioblastoma and exosomes, describing highlight studies that demonstrate the role of exosomes in the tumor microenvironment of GBM and their potential for non-invasive diagnoses and therapeutic approaches, namely, as nanocarriers for drug or gene delivery and cancer vaccines.

Surface Glycan Profiling of Extracellular Vesicles by Lectin Microarray and Glycoengineering for Control of Cellular Interactions

BACKGROUND

Extracellular vesicles (EVs) are a group of cell-derived membrane vesicles that carry a variety of cargo such as protein, nucleic acids, and lipids, and are secreted by almost all cell types. Functionally, EVs play important roles in physiological and pathological processes such as immune responses and tumor growth through intercellular communication by transferring this molecular information between cells. Therefore, they have potential versatile clinical applications as disease biomarkers and drug delivery carriers.

PROBLEM

Notably, subpopulations of EVs exhibit distinct characteristics depending on their cell of origin, including the expression of surface glycans, which have been implicated in a variety of cellular processes such as field cancerization, cell recognition, and signal transduction. However, these are features have not been fully exploited because of the difficulty in analyzing these proteins.

APPROACH

In this paper, we summarize the advancements in glycoengineering and high-performance lectin microarray for high-throughput analysis of EV glycans to generate an index of heterogeneity to identify disease biomarkers, and describe how understanding the function of EVs in disease can enhance their potential application in the clinic.

Recent advances of small extracellular vesicle biomarkers in breast cancer diagnosis and prognosis

Current clinical tools for breast cancer (BC) diagnosis are insufficient but liquid biopsy of different bodily fluids has recently emerged as a minimally invasive strategy that provides a real-time snapshot of tumour biomarkers for early diagnosis, active surveillance of progression, and post-treatment recurrence. Extracellular vesicles (EVs) are nano-sized membranous structures 50-1000 nm in diameter that are released by cells into biological fluids. EVs contain proteins, nucleic acids, and lipids which play pivotal roles in tumourigenesis and metastasis through cell-to-cell communication. Proteins and miRNAs from small EVs (sEV), which range in size from 50-150 nm, are being investigated as a potential source for novel BC biomarkers using mass spectrometry-based proteomics and next-generation sequencing. This review covers recent developments in sEV isolation and single sEV analysis technologies and summarises the sEV protein and miRNA biomarkers identified for BC diagnosis, prognosis, and chemoresistance. The limitations of current sEV biomarker research are discussed along with future perspective applications.

Therapeutic potential of small extracellular vesicles derived from mesenchymal stem cells for spinal cord and nerve injury

Neural diseases such as compressive, congenital, and traumatic injuries have diverse consequences, from benign mild sequelae to severe life-threatening conditions with associated losses of motor, sensory, and autonomic functions. Several approaches have been adopted to control neuroinflammatory cascades. Traditionally, mesenchymal stem cells (MSCs) have been regarded as therapeutic agents, as they possess growth factors and cytokines with potential anti-inflammatory and regenerative effects. However, several animal model studies have reported conflicting outcomes, and therefore, the role of MSCs as a regenerative source for the treatment of neural pathologies remains debatable. In addition, issues such as heterogeneity and ethical issues limited their use as therapeutic agents. To overcome the obstacles associated with the use of traditional agents, we explored the therapeutic potentials of extracellular vesicles (EVs), which contain nucleic acids, functional proteins, and bioactive lipids, and play crucial roles in immune response regulation, inflammation reduction, and cell-to-cell communication. EVs may surpass MSCs in size issue, immunogenicity, and response to the host environment. However, a comprehensive review is required on the therapeutic potential of EVs for the treatment of neural pathologies. In this review, we discuss the action mechanism of EVs, their potential for treating neural pathologies, and future perspectives regarding their clinical applications.

Role of Exosomal Non-Coding RNA in the Tumour Microenvironment of Genitourinary System Tumours

In recent years, genitourinary system tumors are common in people of all ages, seriously affecting the quality of life of patients, the pathogenesis and treatment of these diseases are constantly being updated and improved. Exosomes, with a lipid bilayer that enable delivery of their contents into body fluids or other cells. Exosomes can regulate the tumor microenvironment, and play an important role in tumor development. In turn, cellular and non-cellular components of tumor microenvironment also affect the occurrence, progression, invasion and metastasis of tumor. Non-coding RNAs have been shown to be able to be ingested and released by exosomes, and are seen as a potential tool in cancer diagnosis and treatment. Here, we summarize the effect of non-coding RNAs of exosome contents on the tumor microenvironment of genitourinary system tumor, expound the significance of non-coding RNAs of exosome in the occurrence, development, diagnosis and treatment of cancers.

Comparison of proteomic landscape of extracellular vesicles in pleural effusions isolated by three strategies

Extracellular vesicles (EVs) derived from pleural effusion (PE) is emerging as disease biomarkers. However, the methods for isolation of EVs from PE (pEVs) were rarely studied. In our study, three methods for isolating pEVs of lung cancer patients were compared, including ultracentrifugation (UC), a combination of UC and size exclusion chromatography (UC-SEC) and a combination of UC and density gradient ultracentrifugation (UC-DGU). The subpopulation of pEVs was identified by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), Western blotting (WB) and nano-flow cytometry (nFCM). Additionally, the proteomic landscape of pEVs was analyzed by Label-free proteomics. The results showed that, compared with UC and UC-DGU, the UC-SEC method separated pEVs with the highest purity. In the proteomic analysis, on average, 1595 proteins were identified in the pEVs isolated by UC-SEC, much more than pEVs isolated by UC (1222) or UC-DGU (807). Furthermore, approximately 90% of identified proteins in each method were found in the EVs public database ExoCarta. Consistent with this, GO annotation indicated that the core proteins identified in each method were mainly enriched in "extracellular exosome." Many of the top 100 proteins with high expression in each method were suggested as protein markers to validate the presence of EVs in the MISEV2018 guidelines. In addition, combined with lung tissue-specific proteins and vesicular membrane proteins, we screened out and validated several novel protein markers (CD11C, HLA DPA1 and HLA DRB1), which were enriched in pEVs rather than in plasma EVs. In conclusion, our study shows that the method of UC-SEC could significantly improve the purity of EVs and the performance of mass spectrometry-based proteomic profiling in analyzing pEVs. The exosomal proteins CD11C, HLA DPA1 and HLA DRB1 may act as potential markers of pEVs. The proteomic analysis of pEVs provides important information and new ideas for studying diseases complicated with PE.

Exosomes─Nature's Lipid Nanoparticles, a Rising Star in Drug Delivery and Diagnostics

Exosomes are a subgroup of nanosized extracellular vesicles enclosed by a lipid bilayer membrane and secreted by most eukaryotic cells. They represent a route of intercellular communication and participate in a wide variety of physiological and pathological processes. The biological roles of exosomes rely on their bioactive cargos, including proteins, nucleic acids, and lipids, which are delivered to target cells. Their distinctive properties─innate stability, low immunogenicity, biocompatibility, and good biomembrane penetration capacity─allow them to function as superior natural nanocarriers for efficient drug delivery. Another notably favorable clinical application of exosomes is in diagnostics. They hold various biomolecules from host cells, which are indicative of pathophysiological conditions; therefore, they are considered vital for biomarker discovery in clinical diagnostics. Here, we use data from the CAS Content Collection and provide a landscape overview of the current state and delineate trends in research advancement on exosome applications in therapeutics and diagnostics across time, geography, composition, cargo loading, and development pipelines. We discuss exosome composition and pathway, from their biogenesis and secretion from host cells to recipient cell uptake. We assess methods for exosome isolation and purification, their clinical applications in therapy and diagnostics, their development pipelines, the exploration goals of the companies, the assortment of diseases they aim to treat, development stages of their research, and publication trends. We hope this review will be useful for understanding the current knowledge in the field of medical applications of exosomes, in an effort to further solve the remaining challenges in fulfilling their potential.

Fighting Fire with Fire: Exosomes and Acute Pancreatitis-Associated Acute Lung Injury

Acute pancreatitis (AP) is a prevalent clinical condition of the digestive system, with a growing frequency each year. Approximately 20% of patients suffer from severe acute pancreatitis (SAP) with local consequences and multi-organ failure, putting a significant strain on patients' health insurance. According to reports, the lungs are particularly susceptible to SAP. Acute respiratory distress syndrome, a severe type of acute lung injury (ALI), is the primary cause of mortality among AP patients. Controlling the mortality associated with SAP requires an understanding of the etiology of AP-associated ALI, the discovery of biomarkers for the early detection of ALI, and the identification of potentially effective drug treatments. Exosomes are a class of extracellular vesicles with a diameter of 30-150 nm that are actively released into tissue fluids to mediate biological functions. Exosomes are laden with bioactive cargo, such as lipids, proteins, DNA, and RNA. During the initial stages of AP, acinar cell-derived exosomes suppress forkhead box protein O1 expression, resulting in M1 macrophage polarization. Similarly, macrophage-derived exosomes activate inflammatory pathways within endothelium or epithelial cells, promoting an inflammatory cascade response. On the other hand, a part of exosome cargo performs tissue repair and anti-inflammatory actions and inhibits the cytokine storm during AP. Other reviews have detailed the function of exosomes in the development of AP, chronic pancreatitis, and autoimmune pancreatitis. The discoveries involving exosomes at the intersection of AP and acute lung injury (ALI) are reviewed here. Furthermore, we discuss the therapeutic potential of exosomes in AP and associated ALI. With the continuous improvement of technological tools, the research on exosomes has gradually shifted from basic to clinical applications. Several exosome-specific non-coding RNAs and proteins can be used as novel molecular markers to assist in the diagnosis and prognosis of AP and associated ALI.

Applications of Exosomes in Diagnosing Muscle Invasive Bladder Cancer

Muscle Invasive Bladder Cancer (MIBC) is a subset of bladder cancer with a significant risk for metastases and death. It accounts for nearly 25% of bladder cancer diagnoses. A diagnostic work-up for MIBC is inclusive of urologic evaluation, radiographic imaging with a CT scan, urinalysis, and cystoscopy. These evaluations, especially cystoscopy, are invasive and carry the risk of secondary health concerns. Non-invasive diagnostics such as urine cytology are an attractive alternative currently being investigated to mitigate the requirement for cystoscopy. A pitfall in urine cytology is the lack of available options with high reliability, specificity, and sensitivity to malignant bladder cells. Exosomes are a novel biomarker source which could resolve some of the concerns with urine cytology, due to the high specificity as the surrogates of tumor cells. This review serves to define muscle invasive bladder cancer, current urine cytology methods, the role of exosomes in MIBC, and exosomes application as a diagnostic tool in MIBC. Urinary exosomes as the specific populations of extracellular vesicles could provide additional biomarkers with specificity and sensitivity to bladder malignancies, which are a consistent source of cellular information to direct clinicians for developing treatment strategies. Given its strong presence and differentiation ability between normal and cancerous cells, exosome-based urine cytology is highly promising in providing a perspective of a patient’s bladder cancer.