Recovery of extracellular vesicles from human breast milk is influenced by sample collection and vesicle isolation procedures

Assessment of isolation strategies to remove caseins for high-quality milk-derived extracellular vesicles

Increasing studies have highlighted the significance of milk-derived extracellular vesicles (MEVs) in mother-newborn integration, as well as their application as novel drug delivery systems and diagnostic biomarkers. However, conventional ultracentrifugation (UC) often results in the co-precipitation of casein micelles in MEV pellets. In this study, we compared methods with different principles to screen the optimal pretreatment in caseins removal, and found that isoelectric precipitation by hydrochloric acid (HA) could most effectively remove caseins in porcine milk. We further characterized MEV populations isolated by UC and HA/UC from diverse aspects, including particle methodology via nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM), RNA and protein contents, and purity analysis. Importantly, the proliferative and anti-inflammatory effects of MEVs were evaluated in vitro, showing the superiority of MEVs via HA/UC in functionality compared with UC. Our results suggest that HA pretreatment before ultracentrifugation could effectively remove caseins and other protein complexes, leading to MEVs via HA/UC with higher purity and more significant effects in vitro. This study provides valuable insights for the advancement of MEVs isolation techniques across different species and accurate function analysis of MEVs.

Extracellular vesicles separated from goat milk by differential centrifugation coupled with sodium citrate pretreatments

Satisfactory separation of milk-derived extracellular vesicles (MEVs) is important for the downstream analysis of the functions and properties of MEVs. However, the presence of abundant proteins in milk hindered the separation of MEVs. In this study, three pretreatment methods, including sodium citrate (SC), acetic acid (AA), and high-speed centrifugation, were adopted to separate MEVs from goat milk while minimizing the impact of protein. The MEVs were then characterized by nanoparticle tracking, transmission electron microscopy and western blotting experiments. The results indicated that pretreatments with AA and SC greatly decreased the impact of casein, but AA pretreatment damaged the surface structure of MEVs. Additionally, the differential centrifugation process resulted in a slight loss of MEVs. Overall, MEVs with small size and high purity can be obtained under 125 k × g centrifugation combined with SC pretreatment, which suggests a promising method for separation of MEVs from goat milk.

Isolation and Characterization of Milk Exosomes for Use in Advanced Therapies

Exosomes are cell-derived extracellular vesicles (EVs) with diameters between 30 and 120 nm. In recent years, several studies have evaluated the therapeutic potential of exosomes derived from different fluids due to their low immunogenicity and high biocompatibility. However, producing exosomes on a large scale is still challenging. One of the fluids from which they could be isolated in large quantities is milk. Moreover, regeneration is a well-known property of milk. The present work seeks to optimize a method for isolating exosomes from bovine and human milk, comparing different storage conditions and different extraction protocols. We found differences in the yield extraction associated with pre-storage milk conditions and observed some differences according to the processing agent. When we removed milk fat globules and added rennet before freezing, we obtained a cleaner final fraction. In summary, we attempted to optimize a rennet-based new milk-exosome isolation method and concluded that pre-treatment, followed by freezing of samples, yielded the best exosome population.

Therapeutic Potential of Bovine Milk-Derived Extracellular Vesicles

Milk is a fundamental component of the human diet, owing to its substantial nutritional content. In addition, milk contains nanoparticles called extracellular vesicles (EVs), which have indicated their potential beneficial roles such as cell-to-cell communication, disease biomarkers, and therapeutics agents. Amidst other types of EVs, milk EVs (MEVs) have their significance due to their high abundance, easy access, and stability in harsh environmental conditions, such as low pH in the gut. There have been plenty of studies conducted to evaluate the therapeutic potential of bovine MEVs over the past few years, and attention has been given to their engineering for drug delivery and targeted therapy. However, there is a gap between the experimental findings available and clinical trials due to the many challenges related to EV isolation, cargo, and the uniformity of the material. This review aims to provide a comprehensive comparison of various techniques for the isolation of MEVs and offers a summary of the therapeutic potential of bovine MEVs described over the last decade, analyzing potential challenges and further applications. Although a number of aspects still need to be further elucidated, the available data point to the role of MEVs as a potential candidate with therapeutics potential, and the supplementation of MEVs would pave the way to understanding their in-depth effects.

Single Extracellular Vesicle Imaging and Computational Analysis Identifies Inherent Architectural Heterogeneity

Evaluating the heterogeneity of extracellular vesicles (EVs) is crucial for unraveling their complex actions and biodistribution. Here, we identify consistent architectural heterogeneity of EVs using cryogenic transmission electron microscopy (cryo-TEM), which has an inherent ability to image biological samples without harsh labeling methods while preserving their native conformation. Imaging EVs isolated using different methodologies from distinct sources, such as cancer cells, normal cells, immortalized cells, and body fluids, we identify a structural atlas of their dominantly consistent shapes. We identify EV architectural attributes by utilizing a segmentation neural network model. In total, 7,576 individual EVs were imaged and quantified by our computational pipeline. Across all 7,576 independent EVs, the average eccentricity was 0.5366 ± 0.2, and the average equivalent diameter was 132.43 ± 67 nm. The architectural heterogeneity was consistent across all sources of EVs, independent of purification techniques, and compromised of single spherical, rod-like or tubular, and double shapes. This study will serve as a reference foundation for high-resolution images of EVs and offer insights into their potential biological impact.

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.

Research advances of tissue-derived extracellular vesicles in cancers

BACKGROUND

Extracellular vesicles (EVs) can mediate cell-to-cell communication and affect various physiological and pathological processes in both parent and recipient cells. Currently, extensive research has focused on the EVs derived from cell cultures and various body fluids. However, insufficient attention has been paid to the EVs derived from tissues. Tissue EVs can reflect the microenvironment of the specific tissue and the cross-talk of communication among different cells, which can provide more accurate and comprehensive information for understanding the development and progression of diseases.

METHODS

We review the state-of-the-art technologies involved in the isolation and purification of tissue EVs. Then, the latest research progress of tissue EVs in the mechanism of tumor occurrence and development is presented. And finally, the application of tissue EVs in the clinical diagnosis and treatment of cancer is anticipated.

RESULTS

We evaluate the strengths and weaknesses of various tissue processing and EVs isolation methods, and subsequently analyze the significance of protein characterization in determining the purity of tissue EVs. Furthermore, we focus on outlining the importance of EVs derived from tumor and adipose tissues in tumorigenesis and development, as well as their potential applications in early tumor diagnosis, prognosis, and treatment.

CONCLUSION

When isolating and characterizing tissue EVs, the most appropriate protocol needs to be specified based on the characteristics of different tissues. Tissue EVs are valuable in the diagnosis, prognosis, and treatment of tumors, and the potential risks associated with tissue EVs need to be considered as therapeutic agents.

Impact of microparticles released during murine systemic inflammation on macrophage activity and reactive nitrogen species regulation

Microparticles (MPs) packaged with numerous bioactive molecules are essential vehicles in cellular communication in various pathological conditions, including systemic inflammation, Whereas MPs are studied mostly upon isolation, their detection in vivo is limited. Impact of MPs might depend on target cell type and cargo they carry; thus herein, we aimed at verifying MPs' impact on macrophages. Unlike neutrophils, monocytes/macrophages are rather inactive during sepsis, and we hypothesized this might be at least partially controlled by MPs. For the above reasons, we focused on the detection of MPs with intravital microscopy (IVM) and report the presence of putative neutrophil-derived MPs in the vasculature of cremaster muscle of endotoxemic mice. Subsequently, we characterized MPs isolated not only from their blood but also from the peritoneal cavity and observed differences in their size, concentration, and cargo. Such MPs were then used to study their impact on RAW 264.7 macrophage cell line performance (cell viability/activity, cytokines, oxygen, and nitrogen reactive species). Addition of MPs to macrophages with or without co-stimulation with lipopolysaccharide did not affect respiratory burst, somewhat decreased mitochondrial activity but increased inducible nitric oxide synthase (iNOS) expression, and NO production especially in case of plasma-derived MPs. The latter MPs carried more iNOS-controlling ceruloplasmin than those discharged into the peritoneal cavity. We conclude that MPs can be detected in vivo with IVM and their cellular origin identified. They are heterogeneous in nature depending on the site of their release. Consequently, microparticles released during systemic inflammation to various body compartments differentially affect macrophages.

Phosphatidylserine-exposing extracellular vesicles in body fluids are an innate defence against apoptotic mimicry viral pathogens

Some viruses are rarely transmitted orally or sexually despite their presence in saliva, breast milk, or semen. We previously identified that extracellular vesicles (EVs) in semen and saliva inhibit Zika virus infection. However, the antiviral spectrum and underlying mechanism remained unclear. Here we applied lipidomics and flow cytometry to show that these EVs expose phosphatidylserine (PS). By blocking PS receptors, targeted by Zika virus in the process of apoptotic mimicry, they interfere with viral attachment and entry. Consequently, physiological concentrations of EVs applied in vitro efficiently inhibited infection by apoptotic mimicry dengue, West Nile, Chikungunya, Ebola and vesicular stomatitis viruses, but not severe acute respiratory syndrome coronavirus 2, human immunodeficiency virus 1, hepatitis C virus and herpesviruses that use other entry receptors. Our results identify the role of PS-rich EVs in body fluids in innate defence against infection via viral apoptotic mimicries, explaining why these viruses are primarily transmitted via PS-EV-deficient blood or blood-ingesting arthropods rather than direct human-to-human contact.

Goat milk extracellular vesicles: Separation comparison of natural carriers for theragnostic application

Goat milk is a complex biological fluid, which in addition to having a high nutritional value, it is an interesting source of extracellular vesicles (EVs). Despite the countless potential applications that they offer in many biological fields, is not easy to compare the different proposed systems, and this is a major limitation for the real translatability of these natural nanoplatforms for theragnostic purposes. Thus, it is useful to further investigate reproducible methods to separate goat milk EVs. The choice of methods but also the preprocessing of milk has an immense impact on the separation, quality, and yield of EVs. Here, we tested four protocols to separate EVs from unpasteurised goat milk: two based on differential ultracentrifugation (DUC) and two on size-exclusion chromatography (SEC). Moreover, we assessed two different approaches of pre-treatment (acidification and precipitation) to facilitate milk protein discharge. To the best of our knowledge, a similar comparison of all performed protocols on raw goat milk has never been published before. Therefore, enriched EV samples were successfully obtained from goat milk using both DUC and SEC. Taken together, our results may be helpful to obtain natural carriers for future theragnostic applications in personalised medicine.

One-week storage of refrigerated bovine milk does not affect the size, concentration, or molecular properties of extracellular vesicles

Milk extracellular vesicles (EV) have gained extensive attention as promising diagnostic and therapeutic tools. Pre-analytical raw milk storage at low temperatures is an ordinary and usually necessary step after sample collection. It is known that direct freezing of unprocessed whole milk contaminates the native pool of milk EV with other cell structures. However, less evidence is available regarding prolonged cooling at 4°C. The current study assessed whether pre-analytical storage of bovine raw milk for several days affected EV isolation and further analysis. To confirm the independence from the health status of the mammary gland, we analyzed milk samples stored at 4°C for 1, 2, 3, and 7 d past collection, respectively, from 2 quarters of the same cow with different somatic cell counts (SCC). Seven days of refrigeration did not change the milk EV size, concentration, or morphology. We did not detect any changes in the EV cargo regarding the amount of protein and RNA, nor in the specific EV markers TSG101, CD9, and CD81 in milk from quarters with high and low SCC. Overall, we observed fewer CD81 and CD9 markers in quarters with high SCC. Moreover, we found no reduction in the mastitis-related miRNA bta-miR-223-3p, suggesting that refrigeration for several days up to 1 wk is a possible storage option compatible with further EV analyses. The findings of this study enhance the confidence that milk EV are highly stable in the raw milk matrix.

Effects of Different Thawing and Warming Processes on Human Milk Composition

The composition of human milk is influenced by storage and processing practices. The effects of thawing and warming practices on human milk composition remain poorly studied despite their prevalence in home, research, and donor milk bank settings. This review comprehensively examines the impact of different thawing and warming methods on nutritional and bioactive human milk components. While some components such as carbohydrates and minerals remain stable under most typical thawing and warming conditions, others, such as fat, immune proteins, bacterial and human cells, and peptide amine hormones, are sensitive to warming. This review has identified that the data on the effects of milk thawing and warming is limited and often contradictory. Given that numerous important components of milk are diminished during cold storage, it is important that thawing and warming practices do not lead to further loss of or alterations to beneficial milk components. Further work in this field will facilitate greater standardization of thawing methods among researchers and underpin recommendations for thawing and warming of expressed milk for parents.

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly.

The diffusion of normal skin wound myofibroblast-derived microvesicles differs according to matrix composition

Microvesicles (MVs) are a subtype of extracellular vesicles that can transfer biological information over long distances, affecting normal and pathological processes including skin wound healing. However, the diffusion of MVs into tissues can be impeded by the extracellular matrix (ECM). We investigated the diffusion of dermal wound myofibroblast-derived MVs into the ECM by using hydrogels composed of different ECM molecules such as fibrin, type III collagen and type I collagen that are present during the healing process. Fluorescent MVs mixed with hydrogels were employed to detect MV diffusion using fluorometric methods. Our results showed that MVs specifically bound type I collagen and diffused freely out of fibrin and type III collagen. Further analysis using flow cytometry and specific inhibitors revealed that MVs bind to type I collagen via the α2β1 integrin. These data demonstrate that MV transport depends on the composition of the wound environment.

Advances in separation and identification of biologically important milk proteins and peptides

Milk is a rich source of biologically important proteins and peptides. In addition, milk contains a variety of extracellular vesicles (EVs), including exosomes, that carry their own proteome cargo. EVs are essential for cell-cell communication and modulation of biological processes. They act as nature carriers of bioactive proteins/peptides in targeted delivery during various physiological and pathological conditions. Identification of the proteins and protein-derived peptides in milk and EVs and recognition of their biological activities and functions had a tremendous impact on food industry, medicine research, and clinical applications. Advanced separation methods, mass spectrometry (MS)-based proteomic approaches and innovative biostatistical procedures allowed for characterization of milk protein isoforms, genetic/splice variants, posttranslational modifications and their key roles, and contributed to novel discoveries. This review article discusses recently published developments in separation and identification of bioactive proteins/peptides from milk and milk EVs, including MS-based proteomic approaches.

Unveiling the Complex World of Extracellular Vesicles: Novel Characterization Techniques and Manufacturing Considerations

Extracellular vesicles (EVs) function as potent mediators of intercellular communication for many in vivo processes, contributing to both health and disease related conditions. Given their biological origins and diverse functionality from correspondingly unique "cargo" compositions, both endogenous and modified EVs are garnering attention as promising therapeutic modalities and vehicles for targeted therapeutic delivery applications. Their diversity in composition, however, has revealed a significant need for more comprehensive analytical-based characterization methods, and manufacturing processes that are consistent and scalable. In this review, we explore the dynamic landscape of EV research and development efforts, ranging from novel isolation approaches, to their analytical assessment through novel characterization techniques, and to their production by industrial-scale manufacturing process considerations. Expanding the horizon of these topics to EVs for in-human applications, we underscore the need for stringent development and adherence to Good Manufacturing Practice (GMP) guidelines. Wherein, the intricate interplay of raw materials, production in bioreactors, and isolation practices, along with analytical assessments compliant with the Minimal Information for Studies of Extracellular Vesicles (MISEV) guidelines, in conjunction with reference standard materials, collectively pave the way for standardized and consistent GMP production processes.

Storage Stability of Blood Samples for miRNAs in Glycosylated Extracellular Vesicles

Extracellular vesicle (EV) miRNAs are promising biomarkers for clinical diagnosis. However, their stability is a crucial concern affecting reliability and accuracy. Factors such as sample collection, processing, storage conditions, and experimental procedures impact EV miRNA stability. Studying EV miRNA stability aims to find optimal handling and storage methods, ensuring integrity and functionality throughout research. In this study, we used RT-qPCR and GlyExo-Capture technology, which can specifically capture glycosylated EVs by lectin, to assess the stability of glycosylated EV miRNAs. We found that slow acceleration centrifugation and two-step centrifugation methods were suitable for subsequent experiments. To ensure uniformity, we recommend using the two-step centrifugation method. We also studied blood storage before serum separation and recommend separation within 2 h at 4 °C or 25 °C. For separated serum samples, higher temperatures accelerated miRNA degradation, and the storage duration should be adjusted based on laboratory conditions. Short-term storage at -20 °C is acceptable for up to 3 months while avoiding repeated freeze-thaw cycles. We developed protective agents to extend the storage time at 25 °C, meeting clinical requirements. Additionally, Lakebio's cfRNA storage tubes effectively preserved the stability of miRNAs in plasma glycosylated EVs. Understanding EV miRNA stability provides insights into optimizing sample handling, storage strategies, and enhancing reliability in clinical applications.

Single extracellular vesicle imaging and computational analysis identifies inherent architectural heterogeneity

Evaluating the heterogeneity of extracellular vesicles (EVs) is crucial for unraveling their complex actions and biodistribution. Here, we identify consistent architectural heterogeneity of EVs using cryogenic transmission electron microscopy (cryo-TEM) which has an inherent ability to image biological samples without harsh labeling methods and while preserving their native conformation. Imaging EVs isolated using different methodologies from distinct sources such as cancer cells, normal cells, and body fluids, we identify a structural atlas of their dominantly consistent shapes. We identify EV architectural attributes by utilizing a segmentation neural network model. In total, 7,576 individual EVs were imaged and quantified by our computational pipeline. Across all 7,576 independent EVs, the average eccentricity was 0.5366, and the average equivalent diameter was 132.43 nm. The architectural heterogeneity was consistent across all sources of EVs, independent of purification techniques, and compromised of single spherical (S. Spherical), rod-like or tubular, and double shapes. This study will serve as a reference foundation for high-resolution EV images and offer insights into their potential biological impact.

Selective labeling of phosphatidylserine for cryo-TEM by a two-step immunogold method

Immunogold labeling in transmission electron microscopy (TEM) utilizes the high electron density of gold nanoparticles conjugated to proteins to identify specific antigens in biological samples. In this work we applied the concept of immunogold labeling for the labeling of negatively charged phospholipids, namely phosphatidylserine, by a simple protocol, performed entirely in the liquid-phase, from which cryo-TEM specimens can be directly prepared. Labeling included a two-step process using biotinylated annexin-V and gold-conjugated streptavidin. We initially applied it on liposomal systems, demonstrating its specificity and selectivity, differentiating between 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS) membranes. We also observed specific labeling on extracellular vesicle samples isolated from THP1 cells and from MDA-468 cells, which underwent stimulations. Finally, we compared the levels of annexin-V labeling on the cells vs. on their isolated EVs by flow cytometry and found a good correlation with the cryo-TEM results. This simple, yet effective labeling technique makes it possible to differentiate between negatively charged and non-negatively charged membranes, thus shillucidating their possible EV shedding mechanism.

Post-insertion technique to introduce targeting moieties in milk exosomes for targeted drug delivery

BACKGROUND

Recently, increased attention has been given on exosomes as ideal nanocarriers of drugs owing to their intrinsic properties that facilitate the transport of biomolecular cargos. However, large-scale exosome production remains a major challenge in the clinical application of exosome-based drug delivery systems. Considering its biocompatibility and stability, bovine milk is a suitable natural source for large-scale and stable exosome production. Because the active-targeting ability of drug carriers is essential to maximize therapeutic efficacy and minimize side effects, precise membrane functionalization strategies are required to enable tissue-specific delivery of milk exosomes with difficulty in post-isolation modification.

METHODS

In this study, the membrane functionalization of a milk exosome platform modified using a simple post-insertion method was examined comprehensively. Exosomes were engineered from bovine milk (mExo) with surface-tunable modifications for the delivery of tumor-targeting doxorubicin (Dox). The surface modification of mExo was achieved through the hydrophobic insertion of folate (FA)-conjugated lipids.

RESULTS

We have confirmed the stable integration of functionalized PE-lipid chains into the mExo membrane through an optimized post-insertion technique, thereby effectively enhancing the surface functionality of mExo. Indeed, the results revealed that FA-modified mExo (mExo-FA) improved cellular uptake in cancer cells via FA receptor (FR)-mediated endocytosis. The designed mExo-FA selectively delivered Dox to FR-positive tumor cells and triggered notable tumor cell death, as confirmed by in vitro and in vivo analyses.

CONCLUSIONS

This simple and easy method for post-isolation modification of the exosomal surface may be used to develop milk-exosome-based drug delivery systems.

Identification of omega-3 oxylipins in human milk-derived extracellular vesicles with pro-resolutive actions in gastrointestinal inflammation

Introduction

Premature infants (PIs) are at risk of suffering necrotizing enterocolitis (NEC), and infants consuming human milk (HM) show a lower incidence than infants receiving formula. The composition of HM has been studied in depth, but the lipid content of HM-derived small extracellular vesicles (HM sEVs) remains unexplored. Identifying these molecules and their biological effects has potential for the treatment of intestinal disorders in PIs and could contribute to the development of HM-based fortified formulas.

Methods

We isolated HM sEVs from HM samples and analyzed their oxylipin content using liquid chromatography coupled to mass spectrometry, which revealed the presence of anti-inflammatory oxylipins. We then examined the efficacy of a mixture of these oxylipins in combating inflammation and fibrosis, in vitro and in a murine model of inflammatory bowel disease (IBD).

Results

HM-related sEVs contained higher concentrations of oxylipins derived from docosahexaenoic acid, an omega-3 fatty acid. Three anti-inflammatory oxylipins, 14-HDHA, 17-HDHA, and 19,20-DiHDPA (ω3 OXLP), demonstrated similar efficacy to HM sEVs in preventing cell injury, inducing re-epithelialization, mitigating fibrosis, and modulating immune responses. Both ω3 OXLP and HM sEVs effectively reduced inflammation in IBD-model mice, preventing colon shortening, infiltration of inflammatory cells and tissue fibrosis.

Discussion

Incorporating this unique cocktail of oxylipins into fortified milk formulas might reduce the risk of NEC in PIs and also provide immunological and neurodevelopmental support.

Human Breast Milk miRNAs: Their Diversity and Potential for Preventive Strategies in Nutritional Therapy

The endogenous miRNAs of breast milk are the products of more than 1000 nonprotein-coding genes, giving rise to mature small regulatory molecules of 19-25 nucleotides. They are incorporated in macromolecular complexes, loaded on Argonaute proteins, sequestrated in exosomes and lipid complexes, or present in exfoliated cells of epithelial, endothelial, or immune origins. Their expression is dependent on the stage of lactation; however, their detection depends on progress in RNA sequencing and the reappraisal of the definition of small RNAs. Some miRNAs from plants are detected in breast milk, opening the possibility of the stimulation of immune cells from the allergy repertoire. Each miRNA harbors a seeding sequence, which targets mRNAs, gene promoters, or long noncoding RNAs. Their activities depend on their bioavailability. Efficient doses of miRNAs are estimated to be roughly 100 molecules in the cytoplasm of target cells from in vitro and in vivo experiments. Each miRNA is included in networks of stimulation/inhibition/sequestration, driving the expression of cellular phenotypes. Three types of stress applied during lactation to manipulate miRNA supply were explored using rodent offspring: a foster mother, a cafeteria diet, and early weaning. This review presents the main mature miRNAs described from current mothers' cohorts and their bioavailability in experimental models as well as studies assessing the potential of miR-26 or miR-320 miRNA families to alter offspring phenotypes.

Proteomic analysis of exosomes derived from human mature milk and colostrum of mothers with term, late preterm, or very preterm delivery

The growth and development of the human brain is a long and complex process that requires a precise sequence of genetic and molecular events. This begins in the third week of gestation with the differentiation of neural progenitor cells and extends at least until late adolescence, possibly for life. One of the defects of this development is that we know very little about the signals that modulate this sequence of events. The first 3 years of life, during breastfeeding, is one of the critical periods in brain development. In these first years of life, it is believed that neurodevelopmental problems may be the molecular causes of mental disorders. Therefore, we herein propose a new hypothesis, according to which the chemical signals that could modulate this entire complex sequence of events appear in this early period, and the molecular level study of human breast milk and colostrum of mothers who give birth to children in different gestation periods could give us information on proteins influencing this process. In this work, we collected milk and colostrum samples (term, late preterm and moderate/very preterm) and exosomes were isolated. The samples of exosomes and complete milk from each fraction were analyzed by LC-ESI-MS/MS. In this work, we describe proteins in the different fractions of mature milk and colostrum of mothers with term, late preterm, or very preterm delivery, which could be involved in the regulation of the nervous system by their functions. We describe how they differ in different types of milk, paving the way for the investigation of possible new neuroregulatory pathways as possible candidates to modulate the nervous system.

Human milk EV-miRNAs: a novel biomarker for air pollution exposure during pregnancy

Exposure to ambient and near-roadway air pollution during pregnancy has been linked with several adverse health outcomes for pregnant women and their babies. Emerging research indicates that microRNA (miRNA) expression can be altered by exposure to air pollutants in a variety of tissues. Additionally, miRNAs from breast tissue and circulating miRNAs have previously been proposed as a biomarker for breast cancer diagnosis and prognosis. Therefore, this study sought to evaluate the associations between pregnancy exposures to ambient (PM10, PM2.5, NO2, O3) and near-roadway air pollution (total NOx, freeway NOx, non-freeway NOx) with breast milk extracellular vesicle miRNA (EV-miRNA), measured at 1-month postpartum, in a cohort of 108 Latina women living in Southern California. We found that PM10 exposure during pregnancy was positively associated with hsa-miR-200c-3p, hsa-miR-200b-3p, and hsa-let-7c-5p, and was negatively associated with hsa-miR-378d. We also found that pregnancy PM2.5 exposure was positively associated with hsa-miR-200c-3p and hsa-miR-200b-3p. First and second trimester exposure to PM10 and PM2.5 was associated with several EV-miRNAs with putative messenger RNA targets related to cancer. This study provides preliminary evidence that air pollution exposure during pregnancy is associated with human milk EV-miRNA expression.

Milk-borne small extracellular vesicles: kinetics and mechanisms of transport, distribution, and elimination

Small extracellular vesicles (sEVs) in milk have the qualities desired for delivering therapeutics to diseased tissues. The production of bovine milk sEVs is scalable (1021 annually per cow), and they resist degradation in the gastrointestinal tract. Most cells studied to date internalize milk sEVs by a saturable process that follows Michaelis-Menten kinetics. The bioavailability of oral milk sEVs is approximately 50%. In addition to crossing the intestinal mucosa, milk sEVs also cross barriers such as the placenta and blood-brain barrier, thereby enabling the delivery of therapeutics to hard-to-reach tissues. In time course studies, levels of milk sEVs peaked in the intestinal mucosa, plasma, and urine approximately 6 h and returned to baseline 24 h after oral gavage in mice. In tissues, milk sEV levels peaked 12 h after gavage. Milk sEVs appear to be biologically safe. No cytokine storm was observed when milk sEVs were added to cultures of human peripheral blood mononuclear cells or administered orally to rats. Liver and kidney function and erythropoiesis were not impaired when milk sEVs were administered to rats by oral gavage for up to 15 days. Protocols for loading milk sEVs with therapeutic cargo are available. Currently, the use of milk sEVs (and other nanoparticles) in the delivery of therapeutics is limited by their rapid elimination through internalization by macrophages and lysosomal degradation in target cells. This mini review discusses the current knowledge base of sEV tissue distribution, excretion in feces and urine, internalization by macrophages, and degradation in lysosomes.

Extracellular vesicle-mediated targeting strategies for long-term health benefits in gestational diabetes

Extracellular vesicles (EVs) are critical mediators of cell communication, playing important roles in regulating molecular cross-talk between different metabolic tissues and influencing insulin sensitivity in both healthy and gestational diabetes mellitus (GDM) pregnancies. The ability of EVs to transfer molecular cargo between cells imbues them with potential as therapeutic agents. During pregnancy, the placenta assumes a vital role in metabolic regulation, with multiple mechanisms of placenta-mediated EV cross-talk serving as central components in GDM pathophysiology. This review focuses on the role of the placenta in the pathophysiology of GDM and explores the possibilities and prospects of targeting the placenta to address insulin resistance and placental dysfunction in GDM. Additionally, we propose the use of EVs as a novel method for targeted therapeutics in treating the dysfunctional placenta. The primary aim of this review is to comprehend the current status of EV targeting approaches and assess the potential application of these strategies in placental therapeutics, thereby delivering molecular cargo and improving maternal and fetal outcomes in GDM. We propose that EVs have the potential to revolutionize GDM management, offering hope for enhanced maternal-fetal health outcomes and more effective treatments.

Evaluation of EV Storage Buffer for Efficient Preservation of Engineered Extracellular Vesicles

Extracellular vesicles (EVs), detectable in all bodily fluids, mediate intercellular communication by transporting molecules between cells. The capacity of EVs to transport molecules between distant organs has drawn interest for clinical applications in diagnostics and therapeutics. Although EVs hold potential for nucleic-acid-based and other molecular therapeutics, the lack of standardized technologies, including isolation, characterization, and storage, leaves many challenges for clinical applications, potentially resulting in misinterpretation of crucial findings. Previously, several groups demonstrated the problems of commonly used storage methods that distort EV integrity. This work aims to evaluate the process to optimize the storage conditions of EVs and then characterize them according to the experimental conditions and the models used previously. Our study reports a highly efficient EV storage condition, focusing on EV capacity to protect their molecular cargo from biological, chemical, and mechanical damage. Compared with commonly used EV storage conditions, our EV storage buffer leads to less size and particle number variation at both 4 °C and -80 °C, enhancing the ability to protect EVs while maintaining targeting functionality.

Influence of technical and maternal-infant factors on the measurement and expression of extracellular miRNA in human milk

Breast milk contains thousands of bioactive compounds including extracellular vesicle microRNAs (EV-miRNAs), which may regulate pathways such as infant immune system development and metabolism. We examined the associations between the expression of EV-miRNAs and laboratory variables (i.e., batch effects, sample characteristics), sequencing quality indicators, and maternal-infant characteristics. The study included 109 Latino mother-infant dyads from the Southern California Mother's Milk Study. Mothers were age 28.0 ± 5.6 and 23-46 days postpartum. We used principal components analysis to evaluate whether EV-miRNA expression was associated with factors of interest. Then, we used linear models to estimate relationships between these factors and specific EV-miRNA counts and analyzed functional pathways associated with those EV-miRNAs. Finally, we explored which maternal-infant characteristics predicted sequencing quality indicators. Sequencing quality indicators, predominant breastfeeding, and breastfeedings/day were associated with EV-miRNA principal components. Maternal body mass index and breast milk collection timing predicted proportion of unmapped reads. Expression of 2 EV-miRNAs were associated with days postpartum, 23 EV-miRNAs were associated with breast milk collection time, 23 EV-miRNAs were associated with predominant breastfeeding, and 38 EV-miRNAs were associated with breastfeedings/day. These EV-miRNAs were associated with pathways including Hippo signaling pathway and ECM-receptor interaction, among others. This study identifies several important factors that may contribute to breast milk EV-miRNA expression. Future studies should consider these findings in the design and analysis of breast milk miRNA research.

Recent Advances in Extracellular Vesicles in Amyotrophic Lateral Sclerosis and Emergent Perspectives

Amyotrophic lateral sclerosis (ALS) is a severe and incurable neurodegenerative disease characterized by the progressive death of motor neurons, leading to paralysis and death. It is a rare disease characterized by high patient-to-patient heterogeneity, which makes its study arduous and complex. Extracellular vesicles (EVs) have emerged as important players in the development of ALS. Thus, ALS phenotype-expressing cells can spread their abnormal bioactive cargo through the secretion of EVs, even in distant tissues. Importantly, owing to their nature and composition, EVs' formation and cargo can be exploited for better comprehension of this elusive disease and identification of novel biomarkers, as well as for potential therapeutic applications, such as those based on stem cell-derived exosomes. This review highlights recent advances in the identification of the role of EVs in ALS etiopathology and how EVs can be promising new therapeutic strategies.

Adapter dimer contamination in sRNA-sequencing datasets predicts sequencing failure and batch effects and hampers extracellular vesicle-sRNA analysis

Small RNA (sRNA) profiling of Extracellular Vesicles (EVs) by Next-Generation Sequencing (NGS) often delivers poor outcomes, independently of reagents, platforms or pipelines used, which contributes to poor reproducibility of studies. Here we analysed pre/post-sequencing quality controls (QC) to predict issues potentially biasing biological sRNA-sequencing results from purified human milk EVs, human and mouse EV-enriched plasma and human paraffin-embedded tissues. Although different RNA isolation protocols and NGS platforms were used in these experiments, all datasets had samples characterized by a marked removal of reads after pre-processing. The extent of read loss between individual samples within a dataset did not correlate with isolated RNA quantity or sequenced base quality. Rather, cDNA electropherograms revealed the presence of a constant peak whose intensity correlated with the degree of read loss and, remarkably, with the percentage of adapter dimers, which were found to be overrepresented sequences in high read-loss samples. The analysis through a QC pipeline, which allowed us to monitor quality parameters in a step-by-step manner, provided compelling evidence that adapter dimer contamination was the main factor causing batch effects. We concluded this study by summarising peer-reviewed published workflows that perform consistently well in avoiding adapter dimer contamination towards a greater likelihood of sequencing success.

Surface protein profiling of milk and serum extracellular vesicles unveils body fluid-specific signatures

Cell-derived extracellular vesicles (EVs) are currently in the limelight as potential disease biomarkers. The promise of EV-based liquid biopsy resides in the identification of specific disease-associated EV signatures. Knowing the reference EV profile of a body fluid can facilitate the identification of such disease-associated EV-biomarkers. With this aim, we purified EVs from paired human milk and serum samples and used the MACSPlex bead-based flow-cytometry assay to capture EVs on bead-bound antibodies specific for a certain surface protein, followed by EV detection by the tetraspanins CD9, CD63, and CD81. Using this approach we identified body fluid-specific EV signatures, e.g. breast epithelial cell signatures in milk EVs and platelet signatures in serum EVs, as well as body fluid-specific markers associated to immune cells and stem cells. Interestingly, comparison of pan-tetraspanin detection (simultaneous CD9, CD63 and CD81 detection) and single tetraspanin detection (detection by CD9, CD63 or CD81) also unveiled body fluid-specific tetraspanin distributions on EVs. Moreover, certain EV surface proteins were associated with a specific tetraspanin distribution, which could be indicative of the biogenesis route of this EV subset. Altogether, the identified body fluid-specific EV profiles can contribute to study EV profile deviations in these fluids during disease processes.

Comprehensive isolation of extracellular vesicles and nanoparticles

There is an increasing appreciation for the heterogeneous nature of extracellular vesicles (EVs). In addition, two nonvesicular extracellular nanoparticles (NVEPs), exomeres and supermeres, have been discovered recently that are enriched in many cargo previously ascribed to EVs. The EV field has largely focused on EV isolation and characterization, while studies on NVEPs are limited. At this juncture, it is critically important to have robust and reliable methods to separate distinct populations of EVs and NVEPs to assign cargo to their correct carrier. Here, we provide a comprehensive step-by-step protocol for sequential isolation of large and small EVs, nonvesicular fractions, exomeres and supermeres from the same starting material. We describe in detail the use of differential ultracentrifugation, filtration, concentration and high-resolution density-gradient fractionation to obtain purified fractions of distinct populations of EVs and NVEPs. This protocol allows assignment and enrichment of a biomolecule of interest to its specific extracellular compartment. Compared to other isolation methods, our protocol has unique advantages, including high purity and reproducibility, with minimal expertise required. The protocol can be applied to purification of EVs and NVEPs from cell culture medium and human plasma and requires ~72 h to complete. Adoption of this protocol will help translational investigators identify potential circulating biomarkers and therapeutic targets for a host of human diseases and allow basic scientists to better understand EV and NVEP biogenesis and function. Overall, this protocol will allow those interested in isolating EVs and extracellular particles to advance scientific inquiry to answer outstanding questions in the field.

Milk-derived extracellular vesicles protect intestinal barrier integrity in the gut-liver axis

Milk-derived extracellular vesicles (mEVs) have been proposed as a potential nanomedicine for intestinal disorders; however, their impact on intestinal barrier integrity in gut inflammation and associated metabolic diseases has not been explored yet. Here, mEVs derived from bovine and human breast milk exert similar protective effects on epithelial tight junction functionality in vitro, survive harsh gastrointestinal conditions ex vivo, and reach the colon in vivo. Oral administration of mEVs restores gut barrier integrity at multiple levels, including mucus, epithelial, and immune barriers, and prevents endotoxin translocation into the liver in chemical-induced experimental colitis and diet-induced nonalcoholic steatohepatitis (NASH), thereby alleviating gut disorders, their associated liver inflammation, and NASH. Oral administration of mEVs has potential in the treatment of gut inflammation and gut-liver axis-associated metabolic diseases via protection of intestinal barrier integrity.

Shaping infant development from the inside out: Bioactive factors in human milk

Human breast milk is the optimal nutrition for all infants and is comprised of many bioactive and immunomodulatory components. The components in human milk, such as probiotics, human milk oligosaccharides (HMOs), extracellular vesicles, peptides, immunoglobulins, growth factors, cytokines, and vitamins, play a critical role in guiding neonatal development beyond somatic growth. In this review, we will describe the bioactive factors in human milk and discuss how these factors shape neonatal immunity, the intestinal microbiome, intestinal development, and more from the inside out.

EVs vs. EVs: MSCs and Tregs as a source of invisible possibilities

Extracellular vesicles (EVs) are produced by various cells and exist in most biological fluids. They play an important role in cell-cell signaling, immune response, and tumor metastasis, and also have theranostic potential. They deliver many functional biomolecules, including DNA, microRNAs (miRNA), messenger RNA (mRNA), long non-coding RNA (lncRNA), lipids, and proteins, thus affecting different physiological processes in target cells. Decreased immunogenicity compared to liposomes or viral vectors and the ability to cross through physiological barriers such as the blood-brain barrier make them an attractive and innovative option as diagnostic biomarkers and therapeutic carriers. Here, we highlighted two types of cells that can produce functional EVs, namely, mesenchymal stem/stromal cells (MSCs) and regulatory T cells (Tregs), discussing MSC/Treg-derived EV-based therapies for some specific diseases including acute respiratory distress syndrome (ARDS), autoimmune diseases, and cancer.

Mapping of the Human Amniotic Membrane: In Situ Detection of Microvesicles Secreted by Amniotic Epithelial Cells

The potential clinical applications of human amniotic membrane (hAM) and human amniotic epithelial cells (hAECs) in the field of regenerative medicine have been known in literature since long. However, it has yet to be elucidated whether hAM contains different anatomical regions with different plasticity and differentiation potential. Recently, for the first time, we highlighted many differences in terms of morphology, marker expression, and differentiation capabilities among four distinct anatomical regions of hAM, demonstrating peculiar functional features in hAEC populations. The aim of this study was to investigate in situ the ultrastructure of the four different regions of hAM by means of transmission electron microscopy (TEM) to deeply understand their peculiar characteristics and to investigate the presence and localization of secretory products because to our knowledge, there are no similar studies in the literature. The results of this study confirm our previous observations of hAM heterogeneity and highlight for the first time that hAM can produce extracellular vesicles (EVs) in a heterogeneous manner. These findings should be considered to increase efficiency of hAM applications within a therapeutic context.

Extracellular Vesicle Isolation and Characterization for Applications in Cartilage Tissue Engineering and Osteoarthritis Therapy

Extracellular vesicles (EVs) have the capacity for use in cartilage tissue engineering by stimulating tissue repair and microenvironmental reprogramming. This makes them ideal candidates for treating focal cartilage defects and cartilage degeneration in osteoarthritis (OA). Observational studies have reported beneficial biological effects of EVs, such as inhibition of inflammation, enhanced extracellular matrix deposition, and reduced cartilage degradation. Isolation of EVs derived from different source materials such as conditioned cell culture media or biofluids is essential to attribute observed biological effects to EVs as genuine effectors. This chapter presents a density- and a size-based method as well as a combination of both for isolation of EVs from conditioned cell culture media or biofluids. In addition, three methods for characterization of isolated EVs are suggested based on physical properties, protein profiling, and ultrastructural morphology.

Extracellular vesicles from amniotic fluid, milk, saliva, and urine expose complexes of tissue factor and activated factor VII

BACKGROUND

Tissue factor (TF) is expressed in the adventitia of the vessel wall and on extracellular vesicles (EVs) in body fluids. TF and activated coagulation factor (F) VII(a) together form the so-called extrinsic tenase complex, which initiates coagulation.

AIM

We investigated whether EVs in amniotic fluid, milk, saliva, and urine expose functional extrinsic tenase complexes that can trigger coagulation.

METHODS

Milk, saliva, and urine were collected from healthy breastfeeding women (n = 6), and amniotic fluid was collected from healthy women undergoing routine amniocentesis (n = 7). EVs were isolated from body fluids by size exclusion chromatography (SEC) and clotting experiments were performed in the presence and absence of antibodies against TF and FVIIa in normal plasma and in FVII-deficient plasma. The ability of body fluids to generate FXa also was determined.

RESULTS

Amniotic fluid, milk, saliva, and urine triggered clotting of normal plasma and of FVII-deficient plasma, which was almost completely inhibited by an anti-FVII antibody and to a lesser extent by an anti-TF antibody. Fractionation of body fluids by SEC showed that only the fractions containing EVs triggered clotting in normal plasma and FVII-deficient plasma and generated FXa, which again was almost completely inhibited by an anti-FVII antibody and partially by an anti-TF antibody.

CONCLUSION

Here we show that EVs from amniotic fluid, milk, saliva, and urine expose complexes of TF and FVIIa (i.e., extrinsic tenase complexes) that directly activate FX. Based on our present findings we propose that these EVs from normal body fluids provide hemostatic protection.

Human milk extracellular vesicles preserve bronchial epithelial barrier integrity and reduce TLR3-induced inflammation in vitro

Breast milk is essential for facilitating the growth and development of infants and for providing immune protection against viral infections in the infant's airways. Yet, regulation of inflammation by milk components may be needed to reduce immune pathology. While milk-derived extracellular vesicles (EVs) are bestowed with immunomodulatory capacities, their role in bronchial epithelial barrier function and inflammation has not yet been examined. We hypothesised that during feeding, milk is not only ingested, but aerosols containing milk EVs are inhaled and locally delivered to the infant's airways to suppress aberrant inflammation. A bronchial epithelial model of viral infection was used to explore the direct effect of milk EVs on cellular barrier function and cytokine release during stimulation with a viral dsRNA analogue (Poly I:C). We demonstrate that milk EVs improved the dsRNA-mediated decrease in ionic barrier integrity, limited tight junction reorganisation and reduced inflammatory cytokine production (IL-6, IL-8 and TNF-α). This protective response was EV-mediated, could be successfully titrated and exhibited a time-dependent response. The results indicate that if EV-containing milk aerosols are inhaled during feeding, this may lead to protection of the airway integrity from adverse inflammatory effects.

Human Milk Extracellular Vesicles: A Biological System with Clinical Implications

The consumption of human milk by a breastfeeding infant is associated with positive health outcomes, including lower risk of diarrheal disease, respiratory disease, otitis media, and in later life, less risk of chronic disease. These benefits may be mediated by antibodies, glycoproteins, glycolipids, oligosaccharides, and leukocytes. More recently, human milk extracellular vesicles (hMEVs) have been identified. HMEVs contain functional cargos, i.e., miRNAs and proteins, that may transmit information from the mother to promote infant growth and development. Maternal health conditions can influence hMEV composition. This review summarizes hMEV biogenesis and functional contents, reviews the functional evidence of hMEVs in the maternal–infant health relationship, and discusses challenges and opportunities in hMEV research.

Microvesicles and Microvesicle-Associated microRNAs Reflect Glioblastoma Regression: Microvesicle-Associated miR-625-5p Has Biomarker Potential

Glioblastoma (GB) is the most aggressive and recurrent form of brain cancer in adults. We hypothesized that the identification of biomarkers such as certain microRNAs (miRNAs) and the circulating microvesicles (MVs) that transport them could be key to establishing GB progression, recurrence and therapeutic response. For this purpose, circulating MVs were isolated from the plasma of GB patients (before and after surgery) and of healthy subjects and characterized by flow cytometry. OpenArray profiling and the individual quantification of selected miRNAs in plasma and MVs was performed, followed by target genes’ prediction and in silico survival analysis. It was found that MVs’ parameters (number, EGFRvIII and EpCAM) decreased after the surgical resection of GB tumors, but the inter-patient variability was high. The expression of miR-106b-5p, miR-486-3p, miR-766-3p and miR-30d-5p in GB patients’ MVs was restored to control-like levels after surgery: miR-106b-5p, miR-486-3p and miR-766-3p were upregulated, while miR-30d-5p levels were downregulated after surgical resection. MiR-625-5p was only identified in MVs isolated from GB patients before surgery and was not detected in plasma. Target prediction and pathway analysis showed that the selected miRNAs regulate genes involved in cancer pathways, including glioma. In conclusion, miR-625-5p shows potential as a biomarker for GB regression or recurrence, but further in-depth studies are needed.

The Therapeutic Potential of Milk Extracellular Vesicles on Colorectal Cancer

Colorectal cancer remains one of the leading prevalent cancers in the world and is the fourth most common cause of death from cancer. Unfortunately, the currently utilized chemotherapies fail in selectively targeting cancer cells and cause harm to healthy cells, which results in profound side effects. Researchers are focused on developing anti-cancer targeted medications, which is essential to making them safer, more effective, and more selective and to maximizing their therapeutic benefits. Milk-derived extracellular vesicles (EVs) from camels and cows have attracted much attention as a natural substitute product that effectively suppresses a wide range of tumor cells. This review sheds light on the biogenesis, methods of isolation, characterization, and molecular composition of milk EVs as well as the therapeutic potentials of milk EVs on colorectal cancer.

Extracellular Vesicles and Hepatocellular Carcinoma: Opportunities and Challenges

The incidence of hepatocellular carcinoma (HCC) is increasing worldwide. Extracellular vesicles (EVs) contain sufficient bioactive substances and are carriers of intercellular information exchange, as well as delivery vehicles for nucleic acids, proteins and drugs. Although EVs show great potential for the treatment of HCC and their role in HCC progression has been extensively studied, there are still many challenges such as time-consuming extraction, difficult storage, easy contamination, and low drug loading rate. We focus on the biogenesis, morphological characteristics, isolation and extraction of EVs and their significance in the progression of HCC, tumor invasion, immune escape and cancer therapy for a review. EVs may be effective biomarkers for molecular diagnosis of HCC and new targets for tumor-targeted therapy.

Extracellular Vesicles: A New Source of Biomarkers in Pediatric Solid Tumors? A Systematic Review

Virtually every cell in the body releases extracellular vesicles (EVs), the contents of which can provide a "fingerprint" of their cellular origin. EVs are present in all bodily fluids and can be obtained using minimally invasive techniques. Thus, EVs can provide a promising source of diagnostic, prognostic, and predictive biomarkers, particularly in the context of cancer. Despite advances using EVs as biomarkers in adult cancers, little is known regarding their use in pediatric cancers. In this review, we provide an overview of published clinical and in vitro studies in order to assess the potential of using EV-derived biomarkers in pediatric solid tumors. We performed a systematic literature search, which yielded studies regarding desmoplastic small round cell tumor, hepatoblastoma, neuroblastoma, osteosarcoma, and rhabdomyosarcoma. We then determined the extent to which the in vivo findings are supported by in vitro data, and vice versa. We also critically evaluated the clinical studies using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) system, and we evaluated the purification and characterization of EVs in both the in vivo and in vitro studies in accordance with MISEV guidelines, yielding EV-TRACK and PedEV scores. We found that several studies identified similar miRNAs in overlapping and distinct tumor entities, indicating the potential for EV-derived biomarkers. However, most studies regarding EV-based biomarkers in pediatric solid tumors lack a standardized system of reporting their EV purification and characterization methods, as well as validation in an independent cohort, which are needed in order to bring EV-based biomarkers to the clinic.

Extracellular vesicles-incorporated microRNA signature as biomarker and diagnosis of prediabetes state and its complications

Extracellular vesicles (EVs) are small anuclear vesicles, delimited by a lipid bilayer, released by almost all cell types, carrying functionally active biological molecules that can be transferred to the neighbouring or distant cells, inducing phenotypical and functional changes, relevant in various physio-pathological conditions. The microRNAs are the most significant active components transported by EVs, with crucial role in intercellular communication and significant effects on recipient cells. They may also server as novel valuable biomarkers for the diagnosis of metabolic disorders. Moreover, EVs are supposed to mediate type 2 diabetes mellitus (T2DM) risk and its progress. The T2DM development is preceded by prediabetes, a state that is associated with early forms of nephropathy and neuropathy, chronic kidney disease, diabetic retinopathy, and increased risk of macrovascular disease. Although the interest of scientists was focused not only on the pathogenesis of diabetes, but also on the early diagnosis, little is known about EVs-incorporated microRNA involvement in prediabetes state and its microvascular and macrovascular complications. Here, we survey the biogenesis, classification, content, biological functions and the most popular primary isolation methods of EVs, review the EVs-associated microRNA profiling connexion with early stages of diabetes and discuss the role of EVs containing specific microRNAs in prediabetes complications.

Extracellular Vesicles in Mycobacteria and Tuberculosis

Tuberculosis (TB) remains a public health issue causing millions of infections every year. Of these, about 15% ultimately result in death. Efforts to control TB include development of new and more effective vaccines, novel and more effective drug treatments, and new diagnostics that test for both latent TB Infection and TB disease. All of these areas of research benefit from a good understanding of the physiology of Mycobacterium tuberculosis (Mtb), the primary causative agent of TB. Mtb secreted protein antigens have been the focus of vaccine and diagnosis research for the past century. Recently, the discovery of extracellular vesicles (EVs) as an important source of secreted antigens in Mtb has gained attention. Similarly, the discovery that host EVs can carry Mtb products during in vitro and in vivo infection has spiked interest because of its potential use in blood-based diagnostics. Despite advances in understanding the content of Mtb and Mtb-infected host extracellular vesicles, our understanding on the biogenesis and role of Mtb and host extracellular vesicles during Mtb infection is still nascent. Here, we explore the current literature on extracellular vesicles regarding Mtb, discuss the host and Mtb extracellular vesicles as distinct entities, and discuss current gaps in the field.

Impact of Storage Conditions on EV Integrity/Surface Markers and Cargos

Extracellular vesicles (EVs) are small biological particles released into biofluids by every cell. Based on their size, they are classified into small EVs (<100 nm or <200 nm) and medium or large EVs (>200 nm). In recent years, EVs have garnered interest for their potential medical applications, including disease diagnosis, cell-based biotherapies, targeted drug delivery systems, and others. Currently, the long-term and short-term storage temperatures for biofluids and EVs are −80 °C and 4 °C, respectively. The storage capacity of EVs can depend on their number, size, function, temperature, duration, and freeze−thaw cycles. While these parameters are increasingly studied, the effects of preservation and storage conditions of EVs on their integrity remain to be understood. Knowledge gaps in these areas may ultimately impede the widespread applicability of EVs. Therefore, this review summarizes the current knowledge on the effect of storage conditions on EVs and their stability and critically explores prospective ways for improving long-term storage conditions to ensure EV stability.

Milk exosomes in nutrition and drug delivery

Exosomes are natural nanoparticles that originate in the endocytic system. Exosomes play an important role in cell-to-cell communication by transferring RNAs, lipids, and proteins from donor cells to recipient cells or by binding to receptors on the recipient cell surface. The concentration of exosomes and the diversity of cargos are high in milk. Exosomes and their cargos resist degradation in the gastrointestinal tract and during processing of milk in dairy plants. They are absorbed and accumulate in tissues following oral administrations, cross the blood-brain barrier, and dietary depletion and supplementation elicit phenotypes. These features have sparked the interest of the nutrition and pharmacology communities for exploring milk exosomes as novel bioactive food compounds and for delivering drugs to diseased tissues. This review discusses the current knowledgebase, uncertainties, and controversies in these lines of scholarly endeavor and health research.