Cow Milk and Intestinal Epithelial Cell-derived Extracellular Vesicles as Systems for Enhancing Oral Drug Delivery

Milk-derived exosomes as functional nanocarriers in wound healing: Mechanisms, applications, and future directions

Wound healing presents a significant challenge in healthcare, imposing substantial physiological and economic burdens. While traditional treatments and stem cell therapies have shown benefits, milk-derived exosomes (MDEs) offer distinct advantages as a cell-free therapeutic approach. MDEs, isolated from mammalian milk, are characterized by their biocompatibility, ease of acquisition, and high yield, making them a promising tool for enhancing wound repair. This review provides a comprehensive analysis of the composition, sources, and extraction methods of MDEs, with a focus on their therapeutic role in both acute and diabetic chronic wounds. MDEs facilitate wound healing through the delivery of bioactive molecules, modulating key processes such as inflammation, angiogenesis, and collagen synthesis. Their ability to regulate complex wound-healing pathways underscores their potential for widespread clinical application. This review highlights the importance of MDEs in advancing wound management and proposes strategies to optimize their use in regenerative medicine.

Exosome-based approaches in cancer along with unlocking new insights into regeneration of cancer-prone tissues

Most eukaryotic cells secrete extracellular vesicles called exosomes, which are involved in intercellular communication. Exosomes play a role in tumor development and metastasis by transporting bioactive chemicals from cancerous cells to other cells in local and distant microenvironments. However, the potential of exosomes can be used by engineering them and considering different therapeutic approaches to overcome tumors. Exosomes are a promising drug delivery approach that can help decrease side effects from traditional treatments like radiation and chemotherapy by acting as targeted agents at the tumor site. The present review provides an overview of exosomes and various aspects of the role of exosomes in cancer development, which include these items: exosomes in cancer diagnosis, exosomes and drug delivery, exosomes and drug resistance, exosomal microRNAs and exosomes in tumor microenvironment, etc. Cancer stem cells release exosomes that nurture tumors, promoting unwanted growth and regeneration, and these types of exosomes should be inhibited. Ironically, exosomes from other cells, such as hepatocytes or mesenchymal stem cells (MSCs), are vital for healing organs like the liver and repairing gastric ulcers. Without proper treatment, this healing process can backfire, potentially leading to disease progression or even cancer. What can be found from various studies about the role of exosomes in the field of cancer is that exosomes act like a double-edged sword; on the other hand, natural exosomes in the body may play an important role in the process and progression of cancer, but by engineering exosomes, they can be directed towards target therapy and targeted delivery of drugs to tumor cells. By examining the role and application of exosomes in various mechanisms of cancer, it is possible to help treat this disease more efficiently and quickly in preclinical and clinical research.

Unlocking exosome therapeutics: The critical role of pharmacokinetics in clinical applications

Exosomes are microscopic vesicles released by cells that transport various biological materials and play a vital role in intercellular communication. When they are engineered, they serve as efficient delivery systems for therapeutic agents, making it possible to precisely deliver active pharmaceutical ingredients to organs, tissues, and cells. Exosomes' pharmacokinetics, or how they are transported and metabolized inside the body, is affected by several factors, including their source of origination and the proteins in their cell membranes. The pharmacokinetics and mobility of both native and modified exosomes are being observed in living organisms using advanced imaging modalities such as in vitro-in vivo simulation, magnetic resonance imaging, and positron emission tomography. Establishing comprehensive criteria for the investigation of exosomal pharmacokinetic is essential, given its increasing significance in both therapy and diagnostics. To obtain a thorough understanding of exosome intake, distribution, metabolism, and excretion, molecular imaging methods are crucial. The development of industrial processes and therapeutic applications depends on the precise measurement of exosome concentration in biological samples. To ensure a seamless incorporation of exosomes into clinical practice, as their role in therapeutics grows, it is imperative to conduct a complete assessment of their pharmacokinetics. This review provides a brief on how exosome-based research is evolving and the need for pharmacokinetic consideration to realize the full potential of these promising new therapeutic approaches.

Extracellular Vesicles: A Review of Their Therapeutic Potentials, Sources, Biodistribution, and Administration Routes

Extracellular vesicles (EVs) participate in intercellular communication and play an essential role in physiological and pathological processes. In recent years, EVs have garnered significant attention as cell-free therapeutic alternatives, vectors for drug and gene delivery, biomarkers for disease diagnosis and prognosis, vaccine development, and nutraceuticals. The biodistribution of EVs critically influences their efficacy and toxicity. Therefore, this review aims to discuss the main factors influencing the biodistribution of unmodified EVs, highlighting their distribution patterns, advantages, limitations, and applications under different routes of administration. In addition, we provide a comprehensive discussion of the currently available sources of EVs and summarize the current status of the therapeutic potentials of EVs. By optimizing administration routes and selecting appropriate EV sources, we aim to offer valuable insights to enhance the delivery efficiency and therapeutic efficacy of EVs to target tissues.

Carrier-free nanoparticles-new strategy of improving druggability of natural products

There are abundant natural products resources and extensive clinical use experience in China. However, the active components of natural products generally have problems such as poor water solubility and low bioavailability, which limit their druggability. Carrier-free nanoparticles, such as nanocrystals, self-assembled nanoparticles, and extracellular vesicles derived from both animal and plant sources, have great application potential in improving the safety and efficacy of drugs due to their simple and flexible preparation methods, high drug loading capacity and delivery efficiency, as well as long half-life in blood circulation. It has been widely used in biomedical fields such as anti-tumor, anti-bacterial, anti-inflammatory and anti-oxidation. Therefore, based on the natural products that have been used in clinic, this review focuses on the advantages of carrier-free nanoparticles in delivering active compounds, in order to improve the delivery process of natural products in vivo and improve their draggability.

Milk-derived extracellular vesicles and gut health

Milk is a nutrient-rich liquid produced by mammals, offering various health benefits due to its composition of proteins, fats, carbohydrates, vitamins, and minerals. Beyond traditional nutritional aspects, recent research has focused on extracellular vesicles (EVs) found in milk and their potential health benefits, especially for gastrointestinal (GI) health. Milk-derived EVs have been shown to influence gut microbiota, promote gut barrier integrity, support tissue repair and regeneration, modulate immune responses, and potentially aid in managing conditions like inflammatory bowel disease (IBD) and colorectal cancer. This review discusses the current understanding of milk-EVs' effects on gut health, highlighting their potential therapeutic applications and future research directions. These findings underscore the promising role of milk-derived EVs in advancing GI health and therapeutics, paving the way for innovative approaches in oral drug delivery and targeted treatments for GI disorders.

Therapeutic potential of human breast milk-derived exosomes in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a severe inflammatory and necrotizing disease of the intestine that primarily affects the neonates, particularly premature infants. It has a high incidence of approximately 8.9% in extremely preterm infants, with a mortality rate ranging from 20 to 30%. In recent years, exosomes, particularly those derived from breast milk, have emerged as potential candidates for NEC therapy. Human breast milk-derived exosomes (BME) have been shown to enhance intestinal barrier function, protect intestinal epithelial cells from oxidative stress, promote the proliferation and migration of intestinal epithelial cells, and reduce the severity of experimental NEC models. As a subset of extracellular vesicles, BME possess the membrane structure, low immunogenicity, and high permeability, making them ideal vehicles for the treatment of NEC. Additionally, exosomes derived from various sources, including stem cells, intestinal epithelial cells, plants, and bacteria, have been implicated in the development and protection of intestinal diseases. This article summarizes the mechanisms through which exosomes, particularly BME, exert their effects on NEC and discusses the feasibility and obstacles associated with this novel therapeutic strategy.

Anthocyanin-loaded milk-derived extracellular vesicles nano-delivery system: Stability, mucus layer penetration, and pro-oxidant effect on HepG2 cells

Anthocyanin (ACN) has attracted considerable attention due to its wide range of physiological effects. However, challenges such as poor stability and limited bioavailability have hindered its utilization in functional foods. To address these issues, this research utilized milk-derived extracellular vesicles (MEV) as carriers for encapsulating and binding ACN through various techniques, including ultrasonic, electroporation, saponin treatment, incubation, and freeze-thaw cycles. The objective of these approaches was to enhance the stability of ACN and improve its oral delivery. Notably, the ACN-loaded MEV (MEV-ACN) prepared through ultrasonic exhibited small particle sizes and good stability under processing, storage, and simulated digestion conditions. Cellular studies revealed that MEV-ACN exhibited pro-oxidant properties and induced oxidative stress, leading to cell apoptosis with greater efficacy compared to free ACN. These findings suggest that encapsulating ACN within MEV can significantly enhance its processing and oral stability, as well as strengthening its dietary defense capabilities in anti-tumor applications.

Food-derived extracellular vesicles: natural nanocarriers for active phytoconstituents in new functional food

Extracellular vesicles (EVs) are naturally occurring non-replicating particles released from cells, known for their health-promoting effects and potential as carriers for drug delivery. Extensive research has been conducted on delivery systems based on culture-cell-derived EVs. Nevertheless, they have several limitations including low production yield, high expenses, unsuitability for oral administration, and safety concerns in applications. Conversely, food-derived EVs (FDEVs) offer unique advantages that cannot be easily substituted. This review provides a comprehensive analysis of the biogenesis pathways, composition, and health benefits of FDEVs, as well as the techniques required for constructing oral delivery systems. Furthermore, it explores the advantages and challenges associated with FDEVs as oral nanocarriers, and discusses the current research advancements in delivering active phytoconstituents. FDEVs, functioning as a nanocarrier platform for the oral delivery of active molecules, present numerous benefits such as convenient administration, high biocompatibility, low toxicity, and inherent targeting. Nevertheless, numerous unresolved issues persist in the isolation, characterization, drug loading, and application of FDEVs. Technical innovation and standardization of quality control are the key points to promote the development of FDEVs. The review aimed to provide frontier ideas and basic quality control guidelines for developing new functional food based on FDEVs oral drug delivery system.

Dairy: Friend or Foe? Bovine Milk-Derived Extracellular Vesicles and Autoimmune Diseases

Due to the availability, scalability, and low immunogenicity, bovine milk-derived extracellular vesicles (MEVs) are increasingly considered to be a promising carrier of nanomedicines for future therapy. However, considering that extracellular vesicles (EVs) are of biological origin, different sources of EVs, including the host origin and the specific cells that produce the EVs, may have different effects on the structure and function of EVs. Additionally, MEVs play an important role in immune regulation, due to their evolutionary conserved cargo, such as cytokines and miRNAs. Their potential effects on different organs, as well as their accumulation in the human body, should not be overlooked. In this review, we have summarized current impacts and research progress brought about by utilizing MEVs as nano-drug carriers. Nevertheless, we also aim to explore the possible connections between the molecules involved in cellular immunity, cytokines and miRNAs of MEVs produced under different health conditions, and autoimmune diseases.

Enhanced therapeutic intervention of curcumin loaded in exosomes derived from milk in alleviating retinal pigment epithelial cells damage

The macula, a small but highly important area in the retina, is crucial for healthy vision. Age-related macular degeneration is responsible for approximately 8.7 % of blindness worldwide, and affected individuals are burgeoning. The age-related macular degeneration is often triggered by oxidative stress and excessive inflammation that damage the retinal pigment epithelial cells in the macula. Curcumin, a potent antioxidant and anti-inflammatory carotenoid, is hampered by low compatibility and stability issues in food science. Innovatively, this study harnessed milk-derived exosomes as a novel delivery method yielding a curcumin-infused system (curcumin@exosome) to increase its biocompatibility and stability. This fusion not only curbed excessive reactive oxygen species but also neutralized H2O2-induced mitochondrial disruption in cellular models. It revitalized retinal pigment epithelial cells, reverting their function near to baseline in vitro. The curcumin@exosome outshined in subduing pro-inflammatory cytokines tumor necrosis factor-α and interleukin-1β induced by sodium iodate. This study illuminates that the curcumin@exosome is promise as a therapeutic intervention for retinal ailments marked by oxidative and inflammatory distress.

Hydrogel encapsulation of mesenchymal stem cells-derived extracellular vesicles as a novel therapeutic approach in cancer therapy

Cell therapy has emerged as one of the most promising approaches to treating disease in recent decades. The application of stem cells in anti-tumor therapy is determined by their varying capacity for proliferation, migration, and differentiation. These capacities are derived from different sources. The use of stem cell carriers in cancer treatment is justified by the following three reasons: (I) shield therapeutic agents from swift biological deterioration; (II) reduce systemic side effects; and (III) increase local therapeutic levels since stem cells have an innate ability to target tumors. The quantity of stem cells confined to the tumor microenvironment determines this system's anti-tumor activity. Nevertheless, there are limitations to the use of different types of stem cells. When immune cells are used in cell therapy, it may lead to cytokine storms and improper reactions to self-antigens. Furthermore, the use of stem cells may result in cancer. Additionally, after an intravenous injection, cells could not migrate to the injury location. Exosomes derived from different cells were thus proposed as possible therapeutic options. Exosomes are becoming more and more well-liked because of their small size, biocompatibility, and simplicity in storage and separation. A number of investigations have shown that adding various medications and microRNAs to exosomes may enhance their therapeutic effectiveness. Thus, it is essential to evaluate studies looking into the therapeutic effectiveness of encapsulated exosomes. In this review, we looked at studies on encapsulated exosomes' use in regenerative medicine and the treatment of cancer. The results imply that the therapeutic potential increases when encapsulated exosomes are used rather than intact exosomes. Therefore, in order to optimize the effectiveness of the treatment, it is advised to implement this technique in accordance with the kind of therapy.

Advances in delivery systems for CRISPR/Cas-mediated cancer treatment: a focus on viral vectors and extracellular vesicles

The delivery of CRISPR/Cas systems holds immense potential for revolutionizing cancer treatment, with recent advancements focusing on extracellular vesicles (EVs) and viral vectors. EVs, particularly exosomes, offer promising opportunities for targeted therapy due to their natural cargo transport capabilities. Engineered EVs have shown efficacy in delivering CRISPR/Cas components to tumor cells, resulting in inhibited cancer cell proliferation and enhanced chemotherapy sensitivity. However, challenges such as off-target effects and immune responses remain significant hurdles. Viral vectors, including adeno-associated viruses (AAVs) and adenoviral vectors (AdVs), represent robust delivery platforms for CRISPR/Cas systems. AAVs, known for their safety profile, have already been employed in clinical trials for gene therapy, demonstrating their potential in cancer treatment. AdVs, capable of infecting both dividing and non-dividing cells, offer versatility in CRISPR/Cas delivery for disease modeling and drug discovery. Despite their efficacy, viral vectors present several challenges, including immune responses and off-target effects. Future directions entail refining delivery systems to enhance specificity and minimize adverse effects, heralding personalized and effective CRISPR/Cas-mediated cancer therapies. This article underscores the importance of optimized delivery mechanisms in realizing the full therapeutic potential of CRISPR/Cas technology in oncology. As the field progresses, addressing these challenges will be pivotal for translating CRISPR/Cas-mediated cancer treatments from bench to bedside.

Extracellular vesicles

Cells, pathogens, and other systems release extracellular vesicles (EVs). The particles promote intercellular communication and contain proteins, lipids, RNA and DNA. Initially considered to be cellular waste in the twentieth century, EVs were becoming recognized for their function in biological communication and control. EVs are divided into many subtypes: exosomes, microvesicles, and apoptotic bodies. Exosomes form in the late endosome/multivesicular body and are released when the compartments fuse with the plasma membrane. Microvesicles are generated by direct budding of the plasma membrane, whereas apoptotic bodies are formed after cellular apoptosis. The new guideline for EVs that describes alternate nomenclature for EVs. The particles modulate the immune response by affecting both innate and adaptive immunity, and their specific the structure allows them to be used as biomarkers to diagnose a variety of diseases. EVs have a wide range of applications, for example, delivery systems for medications and genetic therapies because of their ability to convey specific cellular material. In anti-tumor therapy, EVs deliver therapeutic chemicals to tumor cells. The EVs promote transplant compatibility and reduce organ rejection. Host-parasite interactions, therapeutic and diagnostic for cancer, cardiovascular disease, cardiac tissue regeneration, and the treatment of neurological diseases such as Alzheimer's and Parkinson's. The study of EVs keeps on expanding, revealing new functions and beneficial options. EVs have the potential to change drug delivery, diagnostics, and specific therapeutics, creating a new frontier in biomedical.

Extracellular Vesicle Preparation and Analysis: A State-of-the-Art Review

In recent decades, research on Extracellular Vesicles (EVs) has gained prominence in the life sciences due to their critical roles in both health and disease states, offering promising applications in disease diagnosis, drug delivery, and therapy. However, their inherent heterogeneity and complex origins pose significant challenges to their preparation, analysis, and subsequent clinical application. This review is structured to provide an overview of the biogenesis, composition, and various sources of EVs, thereby laying the groundwork for a detailed discussion of contemporary techniques for their preparation and analysis. Particular focus is given to state-of-the-art technologies that employ both microfluidic and non-microfluidic platforms for EV processing. Furthermore, this discourse extends into innovative approaches that incorporate artificial intelligence and cutting-edge electrochemical sensors, with a particular emphasis on single EV analysis. This review proposes current challenges and outlines prospective avenues for future research. The objective is to motivate researchers to innovate and expand methods for the preparation and analysis of EVs, fully unlocking their biomedical potential.

Potential of Milk-Derived Extracellular Vesicles as Carriers for Oral Delivery of Active Phytoconstituents

Extracellular vesicles (EVs) play a crucial role in intercellular communication and have the potential to serve as in vivo carriers for delivering active molecules. The biocompatibility advantages of EVs over artificial nanocarriers create new frontiers for delivering modern active molecules. Milk is a favorable source of EVs because of its high bioavailability, low immunogenicity, and commercial producibility. In this review, we analyzed the advantages of milk-derived EVs in the oral delivery of active molecules, discussed their research progress in delivering active phytoconstituents, and summarized the necessary technologies and critical unit operations required for the development of an oral delivery system based on EVs. The review aims to provide innovative ideas and fundamental quality control guidelines for developing the next-generation oral drug delivery system based on milk-derived EVs.

Milk-Derived Extracellular Vesicles: Biomedical Applications, Current Challenges, and Future Perspectives

Extracellular vesicles (EVs) are nano to-micrometer-sized sacs that are released by almost all animal and plant cells and act as intercellular communicators by transferring their cargos between the source and target cells. As a safe and scalable alternative to conditioned medium-derived EVs, milk-derived EVs (miEVs) have recently gained a great deal of popularity. Numerous studies have shown that miEVs have intrinsic therapeutic actions that can treat diseases and enhance human health. Additionally, they can be used as natural drug carriers and novel classes of biomarkers. However, due to the complexity of the milk, the successful translation of miEVs from benchtop to bedside still faces several unfilled gaps, especially a lack of standardized protocols for the isolation of high-purity miEVs. In this work, by comprehensively reviewing the bovine miEVs studies, we provide an overview of current knowledge and research on miEVs while highlighting their challenges and enormous promise as a novel class of theranostics. It is hoped that this study will pave the way for clinical applications of miEVs by addressing their challenges and opportunities.

Gelatin Microspheres Based on H8-Loaded Macrophage Membrane Vesicles to Promote Wound Healing in Diabetic Mice

Diabetic wound healing remains a worldwide challenge for both clinicians and researchers. The high expression of matrix metalloproteinase 9 (MMP9) and a high inflammatory response are indicative of poor diabetic wound healing. H8, a curcumin analogue, is able to treat diabetes and is anti-inflammatory, and our pretest showed that it has the potential to treat diabetic wound healing. However, H8 is highly expressed in organs such as the liver and kidney, resulting in its unfocused use in diabetic wound targeting. (These data were not published, see Table S1 in the Supporting Information.) Accordingly, it is important to pursue effective carrier vehicles to facilitate the therapeutic uses of H8. The use of H8 delivered by macrophage membrane-derived nanovesicles provides a potential strategy for repairing diabetic wounds with improved drug efficacy and fast healing. In this study, we fabricated an injectable gelatin microsphere (GM) with sustained MMP9-responsive H8 macrophage membrane-derived nanovesicles (H8NVs) with a targeted release to promote angiogenesis that also reduces oxidative stress damage and inflammation, promoting diabetic wound healing. Gelatin microspheres loaded with H8NV (GMH8NV) stimulated by MMP9 can significantly facilitate the migration of NIH-3T3 cells and facilitate the development of tubular structures by HUVEC in vitro. In addition, our results demonstrated that GMH8NV stimulated by MMP9 protected cells from oxidative damage and polarized macrophages to the M2 phenotype, leading to an inflammation inhibition. By stimulating angiogenesis and collagen deposition, inhibiting inflammation, and reducing MMP9 expression, GMH8NV accelerated wound healing. This study showed that GMH8NVs were targeted to release H8NV after MMP9 stimulation, suggesting promising potential in achieving satisfactory healing in diabetic treatment.

Milk Extracellular Vesicles: Natural Nanoparticles for Enhancing Oral Drug Delivery against Bacterial Infections

Oral drug delivery is typically preferred as a therapeutic intervention due to the complexities and expenses associated with intravenous administration. However, some drugs are poorly absorbed orally, requiring intravenous administration to bypass the gastrointestinal tract and deliver the drug directly into the bloodstream. Thus, there is an urgent need to develop novel drug delivery platforms to overcome the challenges of oral drug delivery with low solubility, low permeability, oral degradation, and low bioavailability. Advances in extracellular vesicles (EVs) as natural carriers have provided emerging approaches to improve potential therapeutic applications. Milk not only contains traditional nutrients but is also rich in EVs. In this Review, we focus mainly on the purification of milk EVs (mEVs), their safety, and the advantages of mEV-based drug carriers in combatting intestinal infections. Additionally, we summarize several advantages of mEVs over conventional synthetic carriers, such as low immunogenicity, high biocompatibility, and the ability to transfer bioactive molecules between cells. Considering the unmet gaps of mEVs in clinical translation, it is essential to review the cargo loading into mEVs and future perspectives for their use as natural drug carriers for oral delivery. This overview of mEV-based drug carriers for oral delivery sheds light on alternative approaches to treat clinical infections associated with intestinal pathogens and the development of novel oral delivery systems.

Engineered and Mimicked Extracellular Nanovesicles for Therapeutic Delivery

Exosomes are spherical extracellular nanovesicles with an endosomal origin and unilamellar lipid-bilayer structure with sizes ranging from 30 to 100 nm. They contain a large range of proteins, lipids, and nucleic acid species, depending on the state and origin of the extracellular vesicle (EV)-secreting cell. EVs' function is to encapsulate part of the EV-producing cell content, to transport it through biological fluids to a targeted recipient, and to deliver their cargos specifically within the aimed recipient cells. Therefore, exosomes are considered to be potential biological drug-delivery systems that can stably deliver their cargo into targeted cells. Various cell-derived exosomes are produced for medical issues, but their use for therapeutic purposes still faces several problems. Some of these difficulties can be avoided by resorting to hemisynthetic approaches. We highlight here the uses of alternative exosome-mimes involving cell-membrane coatings on artificial nanocarriers or the hybridization between exosomes and liposomes. We also detail the drug-loading strategies deployed to make them drug-carrier systems and summarize the ongoing clinical trials involving exosomes or exosome-like structures. Finally, we summarize the open questions before considering exosome-like disposals for confident therapeutic delivery.

Role of extracellular vesicles in insulin resistance: Signaling pathways, bioactive substances, miRNAs, and therapeutic potential

Extracellular vesicles are small lipid bilayer particles that resemble the structure of cells and range in size from 30 to 1000 nm. They transport a variety of physiologically active molecules, such as proteins, lipids, and miRNAs. Insulin resistance (IR) is a pathological disease in which insulin-responsive organs or components become less sensitive to insulin's physiological effects, resulting in decreased glucose metabolism in target organs such as the liver, muscle, and adipose tissue. Extracellular vesicles have received a lot of attention as essential intercellular communication mediators in the setting of IR. This review looks at extracellular vesicles' role in IR from three angles: signaling pathways, bioactive compounds, and miRNAs. Relevant publications are gathered to investigate the induction, inhibition, and bidirectional regulation of extracellular vesicles in IR, as well as their role in insulin-related illnesses. Furthermore, considering the critical function of extracellular vesicles in regulating IR, the study analyzes the practicality of employing extracellular vesicles for medication delivery and the promise of combination therapy for IR.

Exosomes and microvesicles in kidney transplantation: the long road from trash to gold

Kidney transplantation significantly enhances the survival rate and quality of life of patients with end-stage kidney disease. The ability to predict post-transplantation rejection events in their early phases can reduce subsequent allograft loss. Therefore, it is critical to identify biomarkers of rejection processes that can be acquired on routine analysis of samples collected by non-invasive or minimally invasive procedures. It is also important to develop new therapeutic strategies that facilitate optimisation of the dose of immunotherapeutic drugs and the induction of allograft immunotolerance. This review explores the challenges and opportunities offered by extracellular vesicles (EVs) present in biofluids in the discovery of biomarkers of rejection processes, as drug carriers and in the induction of immunotolerance. Since EVs are highly complex structures and their composition is affected by the parent cell's metabolic status, the importance of defining standardised methods for isolating and characterising EVs is also discussed. Understanding the major bottlenecks associated with all these areas will promote the further investigation of EVs and their translation into a clinical setting.

Characterization and comparison of human and mouse milk cells

Recent data has characterized human milk cells with unprecedented detail and provided insight into cell populations. While such analysis of freshly expressed human milk has been possible, studies of cell functionality within the infant have been limited to animal models. One commonly used animal model for milk research is the mouse; however, limited data are available describing the composition of mouse milk. In particular, the maternal cells of mouse milk have not been previously characterized in detail, in part due to the difficulty in collecting sufficient volumes of mouse milk. In this study, we have established a method to collect high volumes of mouse milk, isolate cells, and compare the cell counts and types to human milk. Surprisingly, we found that mouse milk cell density is three orders of magnitude higher than human milk. The cell types present in the milk of mice and humans are similar, broadly consisting of mammary epithelial cells and immune cells. These results provide a basis of comparison for mouse and human milk cells and will inform the most appropriate uses of mouse models for the study of human phenomena.

Extracellular vesicles and exosome-like nanovesicles as pioneering oral drug delivery systems

As extracellular vesicle (EV)-based nanotechnology has developed rapidly, it has made unprecedented opportunities for nanomedicine possible. EVs and exosome-like nanovesicles (ELNVs) are natural nanocarriers with unique structural, compositional, and morphological characteristics that provide excellent physical, chemical, and biochemical properties. In this literature, we examine the characteristics of EVs, including how they are administered orally and their therapeutic activity. According to the current examples of EVs and ELNVs for oral delivery, milk and plant EVs can exert therapeutic effects through their protein, nucleic acid, and lipid components. Furthermore, several methods for loading drugs into exosomes and targeting exosomes have been employed to investigate their therapeutic capability. Moreover, we discuss EVs as potential drug carriers and the potential role of ELNVs for disease prevention and treatment or as potential drug carriers in the future. In conclusion, the issues associated with the development of EVs and ELNVs from sources such as milk and plants, as well as concerns with standardized applications of these EVs, are discussed.

Temozolomide and flavonoids against glioma: from absorption and metabolism to exosomal delivery

Patients with glioblastoma multiforme and anaplastic astrocytoma are treated with temozolomide. Although it has been demonstrated that temozolomide increases GBM patient survival, it has also been connected to negative immune-related adverse effects. Numerous research investigations have shown that flavonoids have strong antioxidant and chemo-preventive effects. Consequently, it might lessen chemotherapeutic medicines' side effects while also increasing therapeutic effectiveness. The need for creating innovative, secure, and efficient drug carriers for cancer therapy has increased over time. Recent research indicates that exosomes have enormous potential to serve as carriers and cutting-edge drug delivery systems to the target cell. In recent years, researchers have been paying considerable attention to exosomes because of their favorable biodistribution, biocompatibility, and low immunogenicity. In the present review, the mechanistic information of the anti-glioblastoma effects of temozolomide and flavonoids coupled with their exosomal delivery to the targeted cell has been discussed. In addition, we discuss the safety aspects of temozolomide and flavonoids against glioma. The in-depth information of temozolomide and flavonoids action via exosomal delivery can unravel novel strategies to target Glioma.

Current Update of Research on Exosomes in Cancer

Exosomes are vesicles secreted by the plasma membrane of the cells delimited by a lipid bilayer membrane into the extracellular space of the cell. Their release is associated with the disposal mechanism to remove unwanted materials from the cells. Exosomes released from primary tumour sites migrate to other parts of the body to create a metastatic environment for spreading the tumour cells. We have reviewed that exosomes interfere with the tumour progression by (i) promoting angiogenesis, (ii) initiating metastasis, (iii) regulating tumour microenvironment (TME) and inflammation, (iv) modifying energy metabolism, and (v) transferring mutations. We have found that EVs play an important role in inducing tumour drug resistance against anticancer drugs. This review discusses the potential of exosomes to generate a significant therapeutic effect along with improved diagnosis, prognosis, insights on the various research conducted and their significant findings of our interest.

Homogenization and thermal processing reduce the concentration of extracellular vesicles in bovine milk

Extracellular vesicles (EVs) in bovine milk confer beneficial physiologic effects to consumers. Industrial processing treatments may affect the amount or bioactivity of EVs intrinsic to bovine milk. We investigated how the content and concentration of EVs were affected by homogenization and thermal processing of raw bovine milk. Raw milk was processed by homogenization, low-temperature (LT) heat, or pasteurization [high-temperature short-time (HTST) and ultra-high-temperature (UHT)] in a pilot processing facility. EVs were isolated from the raw and processed bovine milk using differential ultracentrifugation and quantified using a nanoparticle tracking analyzer. Bovine milk EVs were assessed for total miRNA and protein concentrations standardized to particle count using a fluorometric assay. There were 1.01 × 1010 (±3.30 × 109) EV particles per ml of bovine milk. All industrial processing treatments caused >60% decrease in EV concentration compared to the raw bovine milk. Homogenization and heat treatments independently and additively reduced the content of EVs in bovine milk. The averages of total miRNA/particle and total protein/particle concentrations were elevated threefold by low-temperature heat-processing treatment relative to HTST and UHT pasteurizations. The average diameter of EVs was reduced by 11%-16% by low temperature compared to raw milk (127 ± 13 nm). Homogenization and pasteurization indiscriminately reduce the EV concentration of bovine milk. Smaller EVs with higher protein content resist degradation when processing bovine milk at sub-pasteurization temperature. This new foundational knowledge may contribute to food product development on the preservation of EVs in processed dairy products, including bovine milk-based infant formulas that some newborns are dependent on for adequate growth and development.

Potential therapeutic effects of milk-derived exosomes on intestinal diseases

Exosomes are extracellular vesicles with the diameter of 30 ~ 150 nm, and are widely involved in intercellular communication, disease diagnosis and drug delivery carriers for targeted disease therapy. Therapeutic application of exosomes as drug carriers is limited due to the lack of sources and methods for obtaining adequate exosomes. Milk contains abundant exosomes, several studies have shown that milk-derived exosomes play crucial roles in preventing and treating intestinal diseases. In this review, we summarized the biogenesis, secretion and structure, current novel methods used for the extraction and identification of exosomes, as well as discussed the role of milk-derived exosomes in treating intestinal diseases, such as inflammatory bowel disease, necrotizing enterocolitis, colorectal cancer, and intestinal ischemia and reperfusion injury by regulating intestinal immune homeostasis, restoring gut microbiota composition and improving intestinal structure and integrity, alleviating conditions such as oxidative stress, cell apoptosis and inflammation, and reducing mitochondrial reactive oxygen species (ROS) and lysosome accumulation in both humans and animals. In addition, we discussed future prospects for the standardization of milk exosome production platform to obtain higher concentration and purity, and complete exosomes derived from milk. Several in vivo clinical studies are needed to establish milk-derived exosomes as an effective and efficient drug delivery system, and promote its application in the treatment of various diseases in both humans and animals.

Probing milk extracellular vesicles for intestinal delivery of RNA therapies

BACKGROUND

Oral delivery remains unattainable for nucleic acid therapies. Many nanoparticle-based drug delivery systems have been investigated for this, but most suffer from poor gut stability, poor mucus diffusion and/or inefficient epithelial uptake. Extracellular vesicles from bovine milk (mEVs) possess desirable characteristics for oral delivery of nucleic acid therapies since they both survive digestion and traverse the intestinal mucosa.

RESULTS

Using novel tools, we comprehensively examine the intestinal delivery of mEVs, probing whether they could be used as, or inform the design of, nanoparticles for oral nucleic acid therapies. We show that mEVs efficiently translocate across the Caco-2 intestinal model, which is not compromised by treatment with simulated intestinal fluids. For the first time, we also demonstrate transport of mEVs in novel 3D 'apical-out' and monolayer-based human intestinal epithelial organoids (IEOs). Importantly, mEVs loaded with small interfering RNA (siRNA) induced (glyceraldehyde 3-phosphate dehydrogenase, GAPDH) gene silencing in macrophages. Using inflammatory bowel disease (IBD) as an example application, we show that administration of anti-tumour necrosis factor alpha (TNFα) siRNA-loaded mEVs reduced inflammation in a IBD rat model.

CONCLUSIONS

Together, this work demonstrates that mEVs could either act as natural and safe systems for oral delivery or nucleic acid therapies, or inform the design of synthetic systems for such application.

A comprehensive review on the composition, biogenesis, purification, and multifunctional role of exosome as delivery vehicles for cancer therapy

All forms of life produce nanosized extracellular vesicles called exosomes, which are enclosed in lipid bilayer membranes. Exosomes engage in cell-to-cell communication and participate in a variety of physiological and pathological processes. Exosomes function via their bioactive components, which are delivered to target cells in the form of proteins, nucleic acids, and lipids. Exosomes function as drug delivery vehicles due to their unique properties of innate stability, low immunogenicity, biocompatibility, biodistribution, accumulation in desired tissues, low toxicity in normal tissues, and the stimulation of anti-cancer immune responses, and penetration capacity into distance organs. Exosomes mediate cellular communications by delivering various bioactive molecules including oncogenes, oncomiRs, proteins, specific DNA, messenger RNA (mRNA), microRNA (miRNA), small interfering RNA (siRNA), and circular RNA (circRNA). These bioactive substances can be transferred to change the transcriptome of target cells and influence tumor-related signaling pathways. After considering all of the available literature, in this review we discuss the biogenesis, composition, production, and purification of exosomes. We briefly review exosome isolation and purification techniques. We explore great-length exosomes as a mechanism for delivering a variety of substances, including proteins, nucleic acids, small chemicals, and chemotherapeutic drugs. We also talk about the benefits and drawbacks of exosomes. This review concludes with a discussion future perspective and challenges. We hope that this review will provide us a better understanding of the current state of nanomedicine and exosome applications in biomedicine.

PIWI-RNAs Small Noncoding RNAs with Smart Functions: Potential Theranostic Applications in Cancer

P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) are a new class of small noncoding RNAs (ncRNAs) that bind components of the PIWI protein family. piRNAs are specifically expressed in different human tissues and regulate important signaling pathways. Aberrant expressions of piRNAs and PIWI proteins have been associated with tumorigenesis and cancer progression. Recent studies reported that piRNAs are contained in extracellular vesicles (EVs), nanosized lipid particles, with key roles in cell-cell communication. EVs contain several bioactive molecules, such as proteins, lipids, and nucleic acids, including emerging ncRNAs. EVs are one of the components of liquid biopsy (LB) a non-invasive method for detecting specific molecular biomarkers in liquid samples. LB could become a crucial tool for cancer diagnosis with piRNAs as biomarkers in a precision oncology approach. This review summarizes the current findings on the roles of piRNAs in different cancer types, focusing on potential theranostic applications of piRNAs contained in EVs (EV-piRNAs). Their roles as non-invasive diagnostic and prognostic biomarkers and as new therapeutic options have been also discussed.

The potential application of encapsulated exosomes: A new approach to increase exosomes therapeutic efficacy

Cell therapy is one of the methods that have shown promising results in treating diseases in recent decades. However, the use of different types of cells comes with limitations. The application of immune cells in cell therapy can lead to cytokine storms and inappropriate responses to self-antigens. Also, the use of stem cells has the potential to create tumors. Also, cells may not migrate to the injury site after intravenous injection. Therefore, using exosomes from different cells as therapeutic candidates were proposed. Due to their small size and favorable characteristics, such as biocompatibility and immunocompatibility, the easy storage and isolation, exosomes have attracted much attention. They are used in treating many diseases, including cardiovascular diseases, orthopedic diseases, autoimmune diseases, and cancer. However, the results of various studies have shown that the therapeutic efficiency of exosomes (Exo) can be increased by loading different drugs and microRNAs inside them (encapsulated exosomes). Therefore, analyzing studies investigating encapsulated exosomes' therapeutic ability is critical. In this study, we have examined the studies related to the use of encapsulated exosomes in treating diseases such as cancer and infectious diseases and their use in regenerative medicine. Compared to intact exosomes, the results show that the application of encapsulated exosomes has a higher therapeutic ability. Therefore it is suggested to use this method depending on the treatment type to increase the treatment's efficiency.

Milk/colostrum exosomes: A nanoplatform advancing delivery of cancer therapeutics

Chemotherapeutics continue to play a central role in the treatment of a wide variety of cancers. Conventional chemotherapy involving bolus intravenous doses results in severe side effects - in some cases life threatening - delayed toxicity and compromised quality-of-life. Attempts to deliver small drug molecules using liposomes, polymeric nanoparticles, micelles, lipid nanoparticles, etc. have produced limited nanoformulations for clinical use, presumably due to a lack of biocompatibility of the material, costs, toxicity, scalability, and/or lack of effective administration. Naturally occurring small extracellular vesicles, or exosomes, may offer a solution and a viable system for delivering cancer therapeutics. Combined with their inherent trafficking ability and versatility of cargo capacity, exosomes can be engineered to specifically target cancerous cells, thereby minimizing off-target effects, and increasing the efficacy of cancer therapeutics. Exosomal formulations have mitigated the toxic effects of several drugs in murine cancer models. In this article, we review studies related to exosomal delivery of both small molecules and biologics, including siRNA to inhibit specific gene expression, in the pursuit of effective cancer therapeutics. We focus primarily on bovine milk and colostrum exosomes as the cancer therapeutic delivery vehicles based on their high abundance, cost effectiveness, scalability, high drug loading, functionalization of exosomes for targeted delivery, and lack of toxicity. While bovine milk exosomes may provide a new platform for drug delivery, extensive comparison to other nanoformulations and evaluation of long-term toxicity will be required to fully realize its potential.

Cell-Derived Vesicles for Antibiotic Delivery-Understanding the Challenges of a Biogenic Carrier System

Recently, extracellular vesicles (EVs) sparked substantial therapeutic interest, particularly due to their ability to mediate targeted transport between tissues and cells. Yet, EVs' technological translation as therapeutics strongly depends on better biocompatibility assessments in more complex models and elementary in vitro-in vivo correlation, and comparison of mammalian versus bacterial vesicles. With this in mind, two new types of EVs derived from human B-lymphoid cells with low immunogenicity and from non-pathogenic myxobacteria SBSr073 are introduced here. A large-scale isolation protocol to reduce plastic waste and cultivation space toward sustainable EV research is established. The biocompatibility of mammalian and bacterial EVs is comprehensively evaluated using cytokine release and endotoxin assays in vitro, and an in vivo zebrafish larvae model is applied. A complex three-dimensional human cell culture model is used to understand the spatial distribution of vesicles in epithelial and immune cells and again used zebrafish larvae to study the biodistribution in vivo. Finally, vesicles are successfully loaded with the fluoroquinolone ciprofloxacin (CPX) and showed lower toxicity in zebrafish larvae than free CPX. The loaded vesicles are then tested effectively on enteropathogenic Shigella, whose infections are currently showing increasing resistance against available antibiotics.

The CRISPR/Cas9 System Delivered by Extracellular Vesicles

Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (Cas) systems can precisely manipulate DNA sequences to change the characteristics of cells and organs, which has potential in the mechanistic research on genes and the treatment of diseases. However, clinical applications are restricted by the lack of safe, targeted and effective delivery vectors. Extracellular vesicles (EVs) are an attractive delivery platform for CRISPR/Cas9. Compared with viral and other vectors, EVs present several advantages, including safety, protection, capacity, penetrating ability, targeting ability and potential for modification. Consequently, EVs are profitably used to deliver the CRISPR/Cas9 in vivo. In this review, the advantages and disadvantages of the delivery form and vectors of the CRISPR/Cas9 are concluded. The favorable traits of EVs as vectors, such as the innate characteristics, physiological and pathological functions, safety and targeting ability of EVs, are summarized. Furthermore, in terms of the delivery of the CRISPR/Cas9 by EVs, EV sources and isolation strategies, the delivery form and loading methods of the CRISPR/Cas9 and applications have been concluded and discussed. Finally, this review provides future directions of EVs as vectors of the CRISPR/Cas9 system in clinical applications, such as the safety, capacity, consistent quality, yield and targeting ability of EVs.

Milk-Derived Exosomes as a Promising Vehicle for Oral Delivery of Hydrophilic Biomacromolecule Drugs

Exosomes, as promising vehicles, have been widely used in the research of oral drug delivery, but the generally low drug loading efficiency of exosomes seriously limits its application and transformation. In this study, we systematically investigated the effects of drug loading methods and physicochemical properties (lipophilicity and molecular weight) on drug loading efficiency of milk-derived exosomes to explore the most appropriate loading conditions. Our finding revealed that the drug loading efficiency of exosomes was closely related to the drug loading method, drug lipophilicity, drug molecular weight and exosome/drug proportions. Of note, we demonstrated the universality that hydrophilic biomacromolecule drugs were the most appropriate loading drugs for milk-derived exosomes, which was attributed to the efficient loading capacity and sustained release behavior. Furthermore, milk-derived exosomes could significantly improve the transepithelial transport and oral bioavailability of model hydrophilic biomacromolecule drugs (octreotide, exendin-4 and salmon calcitonin). Collectively, our results suggested that the encapsulation of hydrophilic biomacromolecule drugs might be the most promising direction for milk exosomes as oral drug delivery vehicles.

Alternative biological sources for extracellular vesicles production and purification strategies for process scale-up

Extracellular vesicles (EVs) are phospholipidic bi-layer enclosed nanoparticles secreted naturally by all cell types. They are attracting increasing attention in the fields of nanomedicine, nutraceutics and cosmetics as biocompatible carriers for drug delivery, with intrinsic properties beneficial to human health. Scientific work now focuses on developing techniques for isolating EVs that can translate into industrial-scale production and meet rigorous clinical requirements. The science of EVs is ongoing, and many pitfalls must be addressed, such as the requirement for standard, reproducible, inexpensive, and Good Manufacturing Practices (GMP) adherent EV processing techniques. Researchers are exploring the use of alternative sources to EVs derived from mammalian cultures, such as plant EVs, as well as the use of bacteria, algae and milk. Regarding the downstream processing of EVs, many alternative techniques to the ultracentrifugation (UC) protocols most commonly used in the laboratory are emerging. In the context of process scale-up, membrane-based processes for isolation and purification of EVs are the most promising, either as stand-alone processes or in combination with chromatographic techniques. This review discusses current trends on EVs source selection and EVs downstream processing techniques, with a focus on plant-derived EVs and membrane-based techniques for EVs enrichment.

Can exosomes transfer the preconditioning effects triggered by (poly)phenol compounds between cells?

Effective strategies in prolonging life- and health span are increasingly recognized as acting as mild stressors. Micronutrients and other dietary compounds such as (poly)phenols may act as moderate stressors and confer protective effects via a preconditioning phenomenon. (Poly)phenols and their metabolites may not need to reach their target cells to produce biologically significant responses, so that cells exposed to it at entry points may communicate signals to other cells. One of such "communication" mechanisms could occur through extracellular vesicles, including exosomes. In vitro loading of exosomes with (poly)phenols has been used to achieve targeted exosome homing. However, it is unknown if similar shuttling phenomena occur in vivo upon (poly)phenols consumption. Alternatively, exposure to (poly)phenols might trigger responses in exposed organs, which can subsequently signal to cells distant from exposure sites via exosomes. The currently available studies favor indirect effects of (poly)phenols, tempting to suggest a "billiard-like" or "domino-like" propagating effect mediated by quantitative and qualitative changes in exosomes triggered by (poly)phenols. In this review, we discuss the limited current data available on how (poly)phenols exposure can potentially modify exosomes activity, highlighting major questions regarding how (epi)genetic, physiological, and gut microbiota factors can modulate and be modulated by the putative exosome-(poly)phenolic compound interplay that still remains to be fully understood.

Extracellular Vesicles Derived From 3D Cultured Antler Stem Cells Serve as a New Drug Vehicle in Osteosarcoma Treatment

Extracellular vesicles (EVs) from antler reserve mesenchymal (RM) cells play an important role in the paracrine regulation during rapid growth of antler without forming a tumor; therefore, RM-EVs become novel materials for anti-tumor studies, such as osteosarcoma treatment. However, the problem of low production of RM-EVs in traditional 2D culture limits its mechanism research and application. In this study, we established an optimal 3D culture system for antler RM cells to produce EVs (3D-RM-EVs). Morphology and property of harvested 3D-RM-EVs were normal compared with EVs from conventional 2D culture, and the miRNA profile in them was basically the same through transcriptome sequencing analysis. Based on the same number of RM cells, the volume of the culture medium collected by 3D cultural system concentrated nearly 30 times, making it more convenient for subsequent purification. In addition, EVs were harvested 30 times in 3D cultural system, greatly increasing the total amount of EVs (harvested a total of 2-3 times in 2D culture). Although 3D-RM-EVs had a limited inhibitory effect on the proliferation of K7M2 cells, the inhibition effect of 3D-RM-EVs loaded drugs (Ifosfamide + Etoposide) were more significant than that of positive drug group alone (P < 0.05). Furthermore, in vivo studies showed that 3D-RM-EVs loaded drugs (Ifosfamide + Etoposide) had the most significant tumor inhibition effect, with decreased tumor size, and could slow down body weight loss compared with Ifosfamide + Etoposide (IFO + ET) group. These results demonstrated that 3D-RM-EVs were efficiently prepared from antler RM cells and were effective as drug vehicles for the treatment of osteosarcoma.

Extracellular Vesicles from Animal Milk: Great Potentialities and Critical Issues

Other than representing the main source of nutrition for newborn mammals, milk delivers a sophisticated signaling system from mother to child that promotes postnatal health. The bioactive components transferred through the milk intake are important for the development of the newborn immune system and include oligosaccharides, lactoferrin, lysozyme, α-La, and immunoglobulins. In the last 15 years, a pivotal role in this mother-to-child exchange has been attributed to extracellular vesicles (EVs). EVs are micro- and nanosized structures enclosed in a phospholipidic double-layer membrane that are produced by all cell types and released in the extracellular environment, reaching both close and distant cells. EVs mediate the intercellular cross-talk from the producing to the receiving cell through the transfer of molecules contained within them such as proteins, antigens, lipids, metabolites, RNAs, and DNA fragments. The complex cargo can induce a wide range of functional modulations in the recipient cell (i.e., anti-inflammatory, immunomodulating, angiogenetic, and pro-regenerative modulations) depending on the type of producing cells and the stimuli that these cells receive. EVs can be recovered from every biological fluid, including blood, urine, bronchoalveolar lavage fluid, saliva, bile, and milk, which is one of the most promising scalable vesicle sources. This review aimed to present the state-of-the-art of animal-milk-derived EV (mEV) studies due to the exponential growth of this field. A focus on the beneficial potentialities for human health and the issues of studying vesicles from milk, particularly for the analytical methodologies applied, is reported.

Nanovesicles-Mediated Drug Delivery for Oral Bioavailability Enhancement

Bioavailability is an eternal topic that cannot be circumvented by peroral drug delivery. Adequate blood drug exposure after oral administration is a prerequisite for effective treatment. Nanovesicles as pleiotropic oral vehicles can solubilize, encapsulate, stabilize an active ingredient and promote the payload absorption via various mechanisms. Vesicular systems with nanoscale size, such as liposomes, niosomes and polymersomes, provide a versatile platform for oral delivery of drugs with distinct nature. The amphiphilicity of vesicles in structure allows hydrophilic and lipophilic molecule(s) either or both to be loaded, being encapsulated in the aqueous cavity or the inner core, respectively. Depending on high oral transport efficiency based on their structural flexibility, gastrointestinal stability, biocompatibility, and/or intestinal epithelial affinity, nanovesicles can markedly augment the oral bioavailability of various poorly absorbed drugs. Vesicular drug delivery systems (VDDSs) demonstrate a lot of preferences and are becoming more prominent of late years in biomedical applications. Equally, these systems can potentiate a drug's therapeutic index by ameliorating the oral absorption. This review devotes to comment on various VDDSs with special emphasis on the peroral drug delivery. The classification of nanovesicles, preparative processes, intestinal transport mechanisms, in vivo fate, and design rationale were expounded. Knowledge on vesicles-mediated oral drug delivery for bioavailability enhancement has been properly provided. It can be concluded that VDDSs with many merits will step into an energetic arena in oral drug delivery.

Exosomes and mimics as novel delivery platform for cancer therapy

Exosomes are nano-sized biological extracellular vesicles transmitting information between cells and constituting a new intercellular communication mode. Exosomes have many advantages as an ideal drug delivery nanocarrier, including good biocompatibility, permeability, low toxicity, and low immunogenicity. Recently, exosomes have been used to deliver chemotherapeutic agents, natural drugs, nucleic acid drugs, and other antitumor drugs to treat many types of tumors. Due to the limited production of exosomes, synthetic exosome-mimics have been developed as an ideal platform for drug delivery. This review summarizes recent advances in the application of exosomes and exosome-mimics delivering therapeutic drugs in treating cancers.

Advanced research on extracellular vesicles based oral drug delivery systems

The oral route is the most convenient and simplest mode of administration. Nevertheless, orally administration of some commonly used therapeutic drugs, such as polypeptides, therapeutic proteins, small-molecule drugs, and nucleic acids, remains a major challenge due to the harsh gastrointestinal environment and the limited oral bioavailability. Extracellular vesicles (EVs) are diverse, nanoscale phospholipid vesicles that are actively released by cells and play crucial roles in intercellular communications. Some EVs have been shown to survive with the gastrointestinal tract (GIT) and can cross biological barriers. The potential of EVs to cross the GIT barrier makes them promising natural delivery carriers for orally administered drugs. Here, we introduce the uniqueness of EVs and their feasibility as oral drug delivery vehicles (ODDVs). Then we provide a general description of the different cellular EVs based oral drug delivery systems (ODDSs) currently under study and emphasize the contribution of endogenous features and multifunctional properties of EVs to the delivery performance. The current obstacles of moving EVs based ODDSs from bench to bedside are also discussed.

Extracellular Vesicles—Oral Therapeutics of the Future

Considered an artifact just after discovery, the possibility of oral delivery of extracellular vesicles (EVs) and their functional cargos has recently gained much research attention. EVs from various sources, including edible plants, milk, bacteria and mammalian cells, have emerged as a platform for miRNA and drug delivery that seem to induce the expected immune effects locally and in distant tissues after oral administration. Such a possibility greatly expands the clinical applicability of EVs. The present review summarizes research findings that either support or deny the biological/therapeutical activity of orally administered EVs and their role in cross-species and cross-kingdom signaling.

Thymoquinone-loaded mesenchymal stem cell-derived exosome as an efficient nano-system against breast cancer cells

Objectives

Exosomes became the subject of extensive research in drug delivery approach due to their potential applicability as therapeutic tools for cancer therapy. Thymoquinone (Tq) is an anti-cancer agent due to its great anti-proliferative effect. However, poor solubility and weak bioavailability restrict its therapeutic applications. In this study, exosomes secreted from human adipocyte-derived mesenchymal stem cells (AdMSCs) were isolated and the efficacy of a novel encapsulation method for loading of Tq was investigated. Finally, the cytotoxic effect of Tq incorporated exosomes against cancer cells was evaluated.

Materials and Methods

Exosomes secreted from AdMSCs were isolated via ultracentrifugation and characterized by electron microscopy and western blotting. Then, through a novel encapsulation approach, Tq was loaded into exosomes by the combination of three methods including incubation, freeze-thawing, and surfactant treatment. Then, the encapsulation efficiency, in vitro cellular uptake, and cytotoxicity of Tq incorporated exosomes (Tq@EXOs) in MCF7 and L929 cells were estimated.

Results

Tq loading into exosomes through our novel method caused a significant improvement in encapsulation efficiency of about 60%. The fluorescent microscopy and flow cytometry outcomes indicated the efficient uptake of Tq@EXOs-FITC by cells throughout 4 hr. Furthermore, MTT results displayed the ability of Tq@EXOs in effectively decreasing the cell viability of MCF7 without causing any obvious cytotoxicity on L929 as normal cells.

Conclusion

The results suggest that our approach provides effective loading of Tq into exosomes which offer a valuable and safe platform for drug delivery to cancer cells thus having a great potential for clinical studies.

The in vivo fate and targeting engineering of crossover vesicle-based gene delivery system

Exosomes and biomimetic vesicles are widely used for gene delivery because of their excellent gene loading capacity and stability and their natural targeting delivery potential. These vesicles take advantages of both cell-based bioactive delivery system and synthetical lipid-derived nanovectors to form crossover characteristics. To further optimize the specific targeting properties of crossover vesicles, studies of their in vivo fate and various engineering approaches including nanobiotechnology are required. This review describes the preparation process of exosomes and biomimetic vesicles, and summarizes the mechanism of loading and delivery of nucleic acids or gene editing systems. We provide a comprehensive overview of the techniques employed for preparing the targeting crossover vesicles based on their cellular uptake and targeting mechanism. To delineate the future prospects of crossover vesicle gene delivery systems, various challenges and clinical applications of vesicles have also been discussed.

Extracellular vesicles expressing CEACAM proteins in the urine of bladder cancer patients

Early detection and long‐term monitoring are important for urothelial carcinoma of the bladder (UCB). Urine cytology and existing markers have insufficient diagnostic performance. Here, we examined medium‐sized extracellular vesicles (EVs) in urine to identify specific markers for UCB and evaluated their usefulness as diagnostic material. To identify specific markers in urinary EVs derived from UCB, we undertook shotgun proteomics using urine from four UCB patients and four healthy subjects. Next, 29 healthy specimens, 18 noncancer specimens, and 33 UCB specimens, all from men, were analyzed for urinary EVs by flow cytometry to evaluate the diagnostic performance of UCB‐specific EVs. Nanoparticle‐tracking analysis indicated that the size of EVs extracted from urine was mostly <400 nm. By shotgun proteomics, we detected several proteins characteristic of UCB and found that carcinoembryonic antigen‐related adhesion molecule (CEACAM) proteins were increased in patients. Flow cytometric analysis revealed that the degree of expression of CEACAM1, CEACAM5, and CEACAM6 proteins on the surface of EVs varied among patients. Extracellular vesicles expressing CEACAM proteins also expressed mucin 1, suggesting that they were derived from tumorigenic uroepithelial cells. The number of EVs expressing CEACAM1, 5, and 6 proteins was significantly increased in UCB (mean ± SD, 8.6 ± 13%) compared to non‐UCB (0.69 ± 0.46) and healthy (0.46 ± 0.34) by flow cytometry. The results of receiver operating characteristic (ROC) analysis showed a good score of area under the ROC curve of 0.907. We identified EVs that specifically express CEACAM proteins in urine and have potential for diagnostic applications. These EVs are potential targets in a new liquid biopsy test for UCB patients.