International Society for Extracellular Vesicles: first annual meeting, April 17-21, 2012: ISEV-2012

Extracellular Vesicles in Acute Kidney Injury: Mechanisms, Biomarkers, and Therapeutic Potential

Acute kidney injury (AKI) has a high morbidity and mortality rate but can only be treated with supportive therapy in most cases. The diagnosis of AKI is mainly based on serum creatinine level and urine volume, which cannot detect kidney injury sensitive and timely. Therefore, new diagnostic and therapeutic molecules of AKI are being actively explored. Extracellular vesicles (EVs), secreted by almost all cells, can originate from different parts of the kidney and mediate intercellular communication between various cell types of nephrons. At present, numerous successful EV-based biomarker discoveries and treatments for AKI have been made, such as the confirmed diagnostic role of urine-derived EVs in AKI and the established therapeutic role of mesenchymal stem cell-derived EVs in AKI have been confirmed; however, these related studies lack a full discussion. In this review, we summarize the latest progression in the profound understanding of the functional role of EVs in AKI caused by various etiologies in recent years and provide new insights into EVs as viable biomarkers and therapeutic molecules for AKI patients. Furthermore, the current challenges and prospects of this research area are briefly discussed, presenting a comprehensive overview of the growing foregrounds of EVs in AKI.

Breaking barriers in targeted Therapy: Advancing exosome Isolation, Engineering, and imaging

Exosomes have emerged as promising tools for targeted drug delivery in biomedical applications and medicine. This review delves into the scientific advancements, challenges, and future prospects specifically associated with these technologies. In this work, we trace the research milestones that led to the discovery and characterization of exosomes and extracellular vesicles, and discuss strategies for optimizing the synthetic yield and the loading of these particles with various therapeutics. In addition, we report the current major issues affecting the field and hampering the clinical translation of these technologies. Highlighting the pivotal role of imaging techniques, we explore how they drive exosome therapy and development by offering insights into biodistribution and cellular trafficking dynamics. Methodologies for vesicle isolation, characterization, loading, and delivery mechanisms are thoroughly examined, alongside strategies aimed at enhancing their therapeutic efficacy. Special emphasis was dedicated to their therapeutic properties, particularly to their ability to deliver biologics into the cytoplasm. Furthermore, we delve into the intricate balance between surface modifications and targeting properties including also transgenic methods aimed at their functionalization and visualization within biological systems. This review underscores the transformative potential of these carriers in targeted drug delivery and identifies crucial areas for further research and clinical translation.

A Reproducible Protocol for the Isolation of Malaria-Derived Extracellular Vesicles by Differential Centrifugation

Over the last few decades, malaria-derived extracellular vesicles (EVs) have gained increasing interest due to their role in disease pathophysiology and parasite biology. Unlike other EV research fields, the isolation of malaria EVs is not standardized, hampering inter-study comparisons. Most malaria EV studies isolate vesicles by the "gold-standard" technique of differential (ultra)centrifugation (DC). Here, we describe in detail an optimized and reproducible protocol for the isolation of malaria-derived EVs by DC. The protocol begins with a description of cultivating high-parasitemia, synchronous P. falciparum cultures that are the source of EV-containing conditioned culture media. The isolation protocol generates two EV subtypes, and we provide details of characterizing these distinct subtypes by analyzing human and parasite proteins by Western blot analysis. We identify some of these proteins as suitable markers for malaria EV subpopulations and subtypes.

Maximizing liposome tumor delivery by hybridizing with tumor-derived extracellular vesicles

Extracellular vesicles (EVs) have gained widespread interest due to their potential in the diagnosis and treatment of inflammation, autoimmune diseases, and cancers. EVs are lipidic vesicles comprising vesicles of endosomal origin called exosomes, microvesicles from membrane shedding, and apoptotic bodies from programmed cell death membrane blebbing that carry complex sets of cargo from their cells of origin, including proteins, lipids, mRNA, and DNA. EVs are rich in integrin proteins that facilitate intrinsic cellular communication to deliver their cargo contents and can also be used as biomarkers to study respective cellular conditions. Within this background, we hypothesized that when these EVs are hybridized with synthetic liposomes, it would help navigate the hybrid construct in the complex biological environment to find its target. Toward this endeavor, we have hybridized a synthetic liposome with EVs (herein called LEVs) derived from mouse breast cancer (4T1 tumors) cells and incorporated a rhodamine-B/near-infrared fluorescent dye to investigate their potential for cellular targeting and tumor delivery. Using membrane extrusion, we have successfully hybridized both entities resulting in the formation of LEVs and characterized their colloidal properties and stability over a period. While EVs are broadly dispersed nano- and micron-sized vesicles, LEVs are engineered as monodispersed with an average hydrodynamic size of 140 ± 5. Using immunoblotting and ELISA, we monitored and quantified the EV-specific protein CD63 and other characteristic proteins such as CD9 and CD81, which were taken as a handle to ensure the reproducibility of EVs and thus LEVs. These LEVs were further challenged with mice bearing orthotopic 4T1 breast tumors and the LEV uptake was found to be maximum in tumors and organs like the liver, spleen, and lungs when compared to control PEGylated liposomes in live animal imaging. Likewise, the constructs were capable of finding lung metastasis as observed in ex vivo imaging. We anticipate that this study can open avenues for drug delivery solutions that are superior in target recognition.

Guidelines for the purification and characterization of extracellular vesicles of parasites

Parasites are responsible for the most neglected tropical diseases, affecting over a billion people worldwide (WHO, 2015) and accounting for billions of cases a year and responsible for several millions of deaths. Research on extracellular vesicles (EVs) has increased in recent years and demonstrated that EVs shed by pathogenic parasites interact with host cells playing an important role in the parasite's survival, such as facilitation of infection, immunomodulation, parasite adaptation to the host environment and the transfer of drug resistance factors. Thus, EVs released by parasites mediate parasite-parasite and parasite-host intercellular communication. In addition, they are being explored as biomarkers of asymptomatic infections and disease prognosis after drug treatment. However, most current protocols used for the isolation, size determination, quantification and characterization of molecular cargo of EVs lack greater rigor, standardization, and adequate quality controls to certify the enrichment or purity of the ensuing bioproducts. We are now initiating major guidelines based on the evolution of collective knowledge in recent years. The main points covered in this position paper are methods for the isolation and molecular characterization of EVs obtained from parasite-infected cell cultures, experimental animals, and patients. The guideline also includes a discussion of suggested protocols and functional assays in host cells.

Standardising the preanalytical reporting of biospecimens to improve reproducibility in extracellular vesicle research - A GEIVEX study

The standardization of clinical studies using extracellular vesicles (EVs) has mainly focused on the procedures employed for their isolation and characterization; however, preanalytical aspects of sample collection, handling and storage also significantly impact the reproducibility of results. We conducted an online survey based on SPREC (Standard PREanalytical Code) among members of GEIVEX (Grupo Español de Investigación en Vesiculas Extracelulares) to explore how different laboratories handled fluid biospecimens destined for EV analyses. We received 70 surveys from forty-three different laboratories: 44% focused on plasma, 9% on serum and 16% on urine. The survey indicated that variability in preanalytical approaches reaches 94%. Moreover, in some cases, researchers had no access to all relevant preanalytical details of samples, with some sample aspects with potential impact on EV isolation/characterisation not coded within the current version of SPREC. Our study highlights the importance of working with common standard operating procedures (SOP) to control preanalytical conditions. The application of SPREC represents a suitable approach to codify and register preanalytical conditions. Integrating SPREC into the SOPs of laboratories/biobanks will provide a valuable source of information and constitute an advance for EV research by improving reproducibility and credibility.

Current theranostic approaches for metastatic cancers through hypoxia-induced exosomal packaged cargo

Tumour cells exhibit numerous defence mechanisms against various therapeutic strategies and help in developing drug resistance. These defence strategies help cancer cells prevent their elimination from an organism and prosper at a specific location. In recent times it's been observed that there is a significant contribution of secreted extracellular vesicles (EVs) from such tumorigenic sites in the development and prognosis of cancer. Amongst the various types of EVs, exosomes behave like biological carriers, play a crucial role in transporting the content between different cells, and had such an underrated defence mode by getting induced due to the hypoxia secreted highly specialised double-membrane structures. These small structure vesicles play a critical part in regulating local microenvironment and intracellular communications, cited by many research studies. Exosomes are a potential carrier of several cargo biomolecules like proteins, lipids, miRNAs, mRNAs etc., facilitating better communication within the microenvironment of cancer cells, enhancing the metastatic rate along with cancer progression. Several studies have extensively researched elucidating exosomes mediated radiation-induced bystander effects: multidrug resistance, epithelial-mesenchymal transition, and help cancer cells escape from the immune system apart from playing a critical role in angiogenesis too. Due to its natural tendency to carry different biomolecules, it can also be used to haul chemical drugs and efficiently deliver the drug molecules to the targeted site of cancer. The current review aims to explore the vivid role of hypoxia-induced exosomes in tumour progression along with its application and challenges in cancer therapeutics.

A brief history of nearly EV-erything - The rise and rise of extracellular vesicles

Extracellular vesicles (EVs) are small cargo-bearing vesicles released by cells into the extracellular space. The field of EVs has grown exponentially over the past two decades; this growth follows the realisation that EVs are not simply a waste disposal system as had originally been suggested by some, but also a complex cell-to-cell communication mechanism. Indeed, EVs have been shown to transfer functional cargo between cells and can influence several biological processes. These small biological particles are also deregulated in disease. As we approach the 75th anniversary of the first experiments in which EVs were unknowingly isolated, it seems right to take stock and look back on how the field started, and has since exploded into its current state. Here we review the early experiments, summarise key findings that have propelled the field, describe the growth of an organised EV community, discuss the current state of the field, and identify key challenges that need to be addressed.

The Past, the Present, and the Future of the Size Exclusion Chromatography in Extracellular Vesicles Separation

Extracellular vesicles (EVs) are cell-derived membranous particles secreted by all cell types (including virus infected and uninfected cells) into the extracellular milieu. EVs carry, protect, and transport a wide array of bioactive cargoes to recipient/target cells. EVs regulate physiological and pathophysiological processes in recipient cells and are important in therapeutics/drug delivery. Despite these great attributes of EVs, an efficient protocol for EV separation from biofluids is lacking. Numerous techniques have been adapted for the separation of EVs with size exclusion chromatography (SEC)-based methods being the most promising. Here, we review the SEC protocols used for EV separation, and discuss opportunities for significant improvements, such as the development of novel particle purification liquid chromatography (PPLC) system capable of tandem purification and characterization of biological and synthetic particles with near-single vesicle resolution. Finally, we identify future perspectives and current issues to make PPLC a tool capable of providing a unified, automated, adaptable, yet simple and affordable particle separation resource.

Pre-metastatic Niche Formation in Different Organs Induced by Tumor Extracellular Vesicles

Primary tumors selectively modify the microenvironment of distant organs such as the lung, liver, brain, bone marrow, and lymph nodes to facilitate metastasis. This supportive metastatic microenvironment in distant organs was termed the pre-metastatic niche (PMN) that is characterized by increased vascular permeability, extracellular matrix remodeling, bone marrow-derived cells recruitment, angiogenesis, and immunosuppression. Extracellular vesicles (EVs) are a group of cell-derived membranous structures that carry various functional molecules. EVs play a critical role in PMN formation by delivering their cargos to recipient cells in target organs. We provide an overview of the characteristics of the PMN in different organs promoted by cancer EVs and the underlying mechanisms in this review.

Communication is key: Extracellular vesicles as mediators of infection and defence during host-microbe interactions in animals and plants

Extracellular vesicles (EVs) are now understood to be ubiquitous mediators of cellular communication. In this review, we suggest that EVs have evolved into a highly regulated system of communication with complex functions including export of wastes, toxins and nutrients, targeted delivery of immune effectors and vectors of RNA silencing. Eukaryotic EVs come in different shapes and sizes and have been classified according to their biogenesis and size distributions. Small EVs (or exosomes) are released through fusion of endosome-derived multivesicular bodies with the plasma membrane. Medium EVs (or microvesicles) bud off the plasma membrane as a form of exocytosis. Finally, large EVs (or apoptotic bodies) are produced as a result of the apoptotic process. This review considers EV secretion and uptake in four eukaryotic kingdoms, three of which produce cell walls. The impacts cell walls have on EVs in plants and fungi are discussed, as are roles of fungal EVs in virulence. Contributions of plant EVs to development and innate immunity are presented. Compelling cases are sporophytic self-incompatibility and cellular invasion by haustorium-forming filamentous pathogens. The involvement of EVs in all of these eukaryotic processes is reconciled considering their evolutionary history.

Extracellular Vesicles in Trypanosomatids: Host Cell Communication

Trypanosoma cruzi, Trypanosoma brucei and Leishmania (Trypanosomatidae: Kinetoplastida) are parasitic protozoan causing Chagas disease, African Trypanosomiasis and Leishmaniases worldwide. They are vector borne diseases transmitted by triatomine bugs, Tsetse fly, and sand flies, respectively. Those diseases cause enormous economic losses and morbidity affecting not only rural and poverty areas but are also spreading to urban areas. During the parasite-host interaction, those organisms release extracellular vesicles (EVs) that are crucial for the immunomodulatory events triggered by the parasites. EVs are involved in cell-cell communication and can act as important pro-inflammatory mediators. Therefore, interface between EVs and host immune responses are crucial for the immunopathological events that those diseases exhibit. Additionally, EVs from these organisms have a role in the invertebrate hosts digestive tracts prior to parasite transmission. This review summarizes the available data on how EVs from those medically important trypanosomatids affect their interaction with vertebrate and invertebrate hosts.

Extracellular Vesicles as Delivery Vehicles of Specific Cellular Cargo

Extracellular vesicles (EVs) mediate cell-to-cell communication via the transfer of biomolecules locally and systemically between organs. It has been elucidated that the specific EV cargo load is fundamental for cellular response upon EV delivery. Therefore, revealing the specific molecular machinery that functionally regulates the precise EV cargo intracellularly is of importance in understanding the role of EVs in physiology and pathophysiology and conveying therapeutic use. The purpose of this review is to summarize recent findings on the general rules, as well as specific modulator motifs governing EV cargo loading. Finally, we address available information on potential therapeutic strategies to alter cargo loading.

Microparticles in systemic sclerosis, targets or tools to control fibrosis: This is the question!

Systemic sclerosis is the main systemic fibrotic disease with unknown etiology characterized by peripheral microvascular injury, activation of immune system, and wide-spread progressive fibrosis. Microparticles can be derived from any cell type during normal cellular differentiation, senescence, and apoptosis, and also upon cellular activation. Carrying along a broad range of surface cytoplasmic and nuclear molecules of originating cells, microparticles are closely implicated in inflammation, thrombosis, angiogenesis, and immunopathogenesis. Recently, microparticles have been proposed as biomarkers of endothelial injury, which is the primary event in the genesis of tissue fibrosis. Microparticles may have a role in fostering endothelial to mesenchymal transition, thus giving a significant contribution to the development of myofibroblasts, the most important final effectors responsible for tissue fibrosis and fibroproliferative vasculopathy. Thanks to potent profibrotic mediators, such as transforming growth factor beta, platelet-derived growth factor, high mobility group box 1 protein, nicotinamide adenine dinucleotide phosphate oxidase 4, and antifibrotic agents, such as matrix metalloproteinases, microparticles may play an opposite role in fibrosis.

Advances in Analysis of Biodistribution of Exosomes by Molecular Imaging

Exosomes are nano-sized membranous vesicles produced by nearly all types of cells. Since exosome-like vesicles are produced in an evolutionarily conserved manner for information and function transfer from the originating cells to recipient cells, an increasing number of studies have focused on their application as therapeutic agents, drug delivery vehicles, and diagnostic targets. Analysis of the in vivo distribution of exosomes is a prerequisite for the development of exosome-based therapeutics and drug delivery vehicles with accurate prediction of therapeutic dose and potential side effects. Various attempts to evaluate the biodistribution of exosomes obtained from different sources have been reported. In this review, we examined the current trends and the advantages and disadvantages of the methods used to determine the biodistribution of exosomes by molecular imaging. We also reviewed 29 publications to compare the methods employed to isolate, analyze, and label exosomes as well as to determine the biodistribution of labeled exosomes.

Mesenchymal Stromal Cell-Based Bone Regeneration Therapies: From Cell Transplantation and Tissue Engineering to Therapeutic Secretomes and Extracellular Vesicles

Effective regeneration of bone defects often presents significant challenges, particularly in patients with decreased tissue regeneration capacity due to extensive trauma, disease, and/or advanced age. A number of studies have focused on enhancing bone regeneration by applying mesenchymal stromal cells (MSCs) or MSC-based bone tissue engineering strategies. However, translation of these approaches from basic research findings to clinical use has been hampered by the limited understanding of MSC therapeutic actions and complexities, as well as costs related to the manufacturing, regulatory approval, and clinical use of living cells and engineered tissues. More recently, a shift from the view of MSCs directly contributing to tissue regeneration toward appreciating MSCs as "cell factories" that secrete a variety of bioactive molecules and extracellular vesicles with trophic and immunomodulatory activities has steered research into new MSC-based, "cell-free" therapeutic modalities. The current review recapitulates recent developments, challenges, and future perspectives of these various MSC-based bone tissue engineering and regeneration strategies.

Dictyostelium: A Model for Studying the Extracellular Vesicle Messengers Involved in Human Health and Disease

Cell-derived extracellular vesicles (EVs) are newly uncovered messengers for intercellular communication. They are released by almost all cell types in the three kingdoms, Archeabacteria, Bacteria and Eukaryotes. They are known to mediate important biological functions and to be increasingly involved in cell physiology and in many human diseases, especially in oncology. The aim of this review is to recapitulate the current knowledge about EVs and to summarize our pioneering work about Dictyostelium discoideum EVs. However, many challenges remain unsolved in the EV research field, before any EV application for theranostics (diagnosis, prognosis, and therapy) of human cancers, can be efficiently implemented in the clinics. Dictyostelium might be an outstanding eukaryotic cell model for deciphering the utmost challenging problem of EV heterogeneity, and for unraveling the still mostly unknown mechanisms of their specific functions as mediators of intercellular communication.

Novel mechanisms regulating endothelial barrier function in the pulmonary microcirculation

The pulmonary epithelial and vascular endothelial cell layers provide two sequential physical and immunological barriers that together form a semi-permeable interface and prevent alveolar and interstitial oedema formation. In this review, we focus specifically on the continuous endothelium of the pulmonary microvascular bed that warrants strict control of the exchange of gases, fluid, solutes and circulating cells between the plasma and the interstitial space. The present review provides an overview of emerging molecular mechanisms that permit constant transcellular exchange between the vascular and interstitial compartment, and cause, prevent or reverse lung endothelial barrier failure under experimental conditions, yet with a clinical perspective. Based on recent findings and at times seemingly conflicting results we discuss emerging paradigms of permeability regulation by altered ion transport as well as shifts in the homeostasis of sphingolipids, angiopoietins and prostaglandins.

Ascent of atomic force microscopy as a nanoanalytical tool for exosomes and other extracellular vesicles

Over the last 30 years, atomic force microscopy (AFM) has made several significant contributions to the field of biology and medicine. In this review, we draw our attention to the recent applications and promise of AFM as a high-resolution imaging and force sensing technology for probing subcellular vesicles: exosomes and other extracellular vesicles. Exosomes are naturally occurring nanoparticles found in several body fluids such as blood, saliva, cerebrospinal fluid, amniotic fluid and urine. Exosomes mediate cell-cell communication, transport proteins and genetic content between distant cells, and are now known to play important roles in progression of diseases such as cancers, neurodegenerative disorders and infectious diseases. Because exosomes are smaller than 100 nm (about 30-120 nm), the structural and molecular characterization of these vesicles at the individual level has been challenging. AFM has revealed a new degree of complexity in these nanosized vesicles and generated growing interest as a nanoscale tool for characterizing the abundance, morphology, biomechanics, and biomolecular make-up of exosomes. With the recent interest in exosomes for diagnostic and therapeutic applications, AFM-based characterization promises to contribute towards improved understanding of these particles at the single vesicle and sub-vesicular levels. When coupled with complementary methods like optical super resolution STED and Raman, AFM could further unlock the potential of exosomes as disease biomarkers and as therapeutic agents.

Detection of Aggregation-Competent Tau in Neuron-Derived Extracellular Vesicles

Progressive cerebral accumulation of tau aggregates is a defining feature of Alzheimer's disease (AD). A popular theory that seeks to explain the apparent spread of neurofibrillary tangle pathology proposes that aggregated tau is passed from neuron to neuron. Such a templated seeding process requires that the transferred tau contains the microtubule binding repeat domains that are necessary for aggregation. While it is not clear how a protein such as tau can move from cell to cell, previous reports have suggested that this may involve extracellular vesicles (EVs). Thus, measurement of tau in EVs may both provide insights on the molecular pathology of AD and facilitate biomarker development. Here, we report the use of sensitive immunoassays specific for full-length (FL) tau and mid-region tau, which we applied to analyze EVs from human induced pluripotent stem cell (iPSC)-derived neuron (iN) conditioned media, cerebrospinal fluid (CSF), and plasma. In each case, most tau was free-floating with a small component inside EVs. The majority of free-floating tau detected by the mid-region assay was not detected by our FL assays, indicating that most free-floating tau is truncated. Inside EVs, the mid-region assay also detected more tau than the FL assay, but the ratio of FL-positive to mid-region-positive tau was higher inside exosomes than in free solution. These studies demonstrate the presence of minute amounts of free-floating and exosome-contained FL tau in human biofluids. Given the potential for FL tau to aggregate, we conclude that further investigation of these pools of extracellular tau and how they change during disease is merited.

Perfusion of isolated rat kidney with Mesenchymal Stromal Cells/Extracellular Vesicles prevents ischaemic injury

Kidney donation after circulatory death (DCD) is a less than ideal option to meet organ shortages. Hypothermic machine perfusion (HMP) with Belzer solution (BS) improves the viability of DCD kidneys, although the graft clinical course remains critical. Mesenchymal stromal cells (MSC) promote tissue repair by releasing extracellular vesicles (EV). We evaluated whether delivering MSC-/MSC-derived EV during HMP protects rat DCD kidneys from ischaemic injury and investigated the underlying pathogenic mechanisms. Warm ischaemic isolated kidneys were cold-perfused (4 hrs) with BS, BS supplemented with MSC or EV. Renal damage was evaluated by histology and renal gene expression by microarray analysis, RT-PCR. Malondialdehyde, lactate, LDH, glucose and pyruvate were measured in the effluent fluid. MSC-/EV-treated kidneys showed significantly less global ischaemic damage. In the MSC/EV groups, there was up-regulation of three genes encoding enzymes known to improve cell energy metabolism and three genes encoding proteins involved in ion membrane transport. In the effluent fluid, lactate, LDH, MDA and glucose were significantly lower and pyruvate higher in MSC/EV kidneys as compared with BS, suggesting the larger use of energy substrates by MSC/EV kidneys. The addition of MSC/EV to BS during HMP protects the kidney from ischaemic injury by preserving the enzymatic machinery essential for cell viability and protects the kidney from reperfusion damage.

Endothelial Extracellular Vesicles-Promises and Challenges

Extracellular vesicles, including exosomes, microparticles, and apoptotic bodies, are phospholipid bilayer-enclosed vesicles that have once been considered as cell debris lacking biological functions. However, they have recently gained immense interest in the scientific community due to their role in intercellular communication, immunity, tissue regeneration as well as in the onset, and progression of various pathologic conditions. Extracellular vesicles of endothelial origin have been found to play a versatile role in the human body, since they are on the one hand known to contribute to cardiovascular diseases, but on the other hand have also been reported to promote endothelial cell survival. Hence, endothelial extracellular vesicles hold promising therapeutic potential to be used as a new tool to detect as well as treat a great number of diseases. This calls for clinically approved, standardized, and efficient isolation and characterization protocols to harvest and purify endothelial extracellular vesicles. However, such methods and techniques to fulfill stringent requirements for clinical trials have yet to be developed or are not harmonized internationally. In this review, recent advances and challenges in the field of endothelial extracellular vesicle research are discussed and current problems and limitations regarding isolation and characterization are pointed out.

Gateway to understanding microparticles: standardized isolation and identification of plasma membrane-derived vesicles

Microparticles (MPs) are small plasma membrane-derived vesicles that can expose molecules originating from their parental cells. As vectors of biological information they are likely to play an active role in both homeostasis and pathogenesis, making them promising biomarkers and nanomedicine tools. Therefore, there is an urgent need for standardization of MP isolation and analysis protocols to propel our understanding of MP biology to the next level. Based on current methodology and recent insights, this review proposes an optimized protocol for the isolation and biochemical characterization of MPs.

Standardization of sample collection, isolation and analysis methods in extracellular vesicle research

The emergence of publications on extracellular RNA (exRNA) and extracellular vesicles (EV) has highlighted the potential of these molecules and vehicles as biomarkers of disease and therapeutic targets. These findings have created a paradigm shift, most prominently in the field of oncology, prompting expanded interest in the field and dedication of funds for EV research. At the same time, understanding of EV subtypes, biogenesis, cargo and mechanisms of shuttling remains incomplete. The techniques that can be harnessed to address the many gaps in our current knowledge were the subject of a special workshop of the International Society for Extracellular Vesicles (ISEV) in New York City in October 2012. As part of the “ISEV Research Seminar: Analysis and Function of RNA in Extracellular Vesicles (evRNA)”, 6 round-table discussions were held to provide an evidence-based framework for isolation and analysis of EV, purification and analysis of associated RNA molecules, and molecular engineering of EV for therapeutic intervention. This article arises from the discussion of EV isolation and analysis at that meeting. The conclusions of the round table are supplemented with a review of published materials and our experience. Controversies and outstanding questions are identified that may inform future research and funding priorities. While we emphasize the need for standardization of specimen handling, appropriate normative controls, and isolation and analysis techniques to facilitate comparison of results, we also recognize that continual development and evaluation of techniques will be necessary as new knowledge is amassed. On many points, consensus has not yet been achieved and must be built through the reporting of well-controlled experiments.

MicroRNAs as pharmacological targets in endothelial cell function and dysfunction

Endothelial cell dysfunction is a term which implies the dysregulation of normal endothelial cell functions, including impairment of the barrier functions, control of vascular tone, disturbance of proliferative, migratory and morphogenic capacities of endothelial cells, as well as control of leukocyte trafficking. MicroRNAs are short non-coding RNAs that have emerged as critical regulators of gene expression acting predominantly at the post-transcriptional level. This review summarizes the latest insights in the identification of endothelial-specific microRNAs and their targets, as well as their roles in controlling endothelial cell functions in both autocrine and paracrine manner. In addition, we discuss the therapeutic potential for the treatment of endothelial cell dysfunction and associated vascular pathophysiological conditions.