Challenges in Exosome Isolation and Analysis in Health and Disease

Abstract

A growing body of evidence emphasizes the important role exosomes in different physiological and pathological conditions. Exosomes, virus-size extracellular vesicles (EVs), carry a complex molecular cargo, which is actively processed in the endocytic compartment of parental cells. Exosomes carry and deliver this cargo to recipient cells, serving as an intercellular communication system. The methods for recovery of exosomes from supernatants of cell lines or body fluids are not uniformly established. Yet, studies of the quality and quantity of exosome cargos underlie the concept of “liquid biopsy.” Exosomes are emerging as a potentially useful diagnostic tool and a predictor of disease progression, response to therapy and overall survival. Although many novel approaches to exosome isolation and analysis of their cargos have been introduced, the role of exosomes as diagnostic or prognostic biomarkers of disease remains unconfirmed. This review considers existing challenges to exosome validation as disease biomarkers. Focusing on advantages and limitations of methods for exosome isolation and characterization, approaches are proposed to facilitate further progress in the development of exosomes as biomarkers in human disease.

Cell-to-Cell Communication in Learning and Memory: From Neuro- and Glio-Transmission to Information Exchange Mediated by Extracellular Vesicles

“…Thus, identification and quantification of specific miRNAs present in circulating, brain-derived EVs can be of the most importance for diagnosis of brain cognition deficit. However, it is worth noting that this important opportunity is still partially hampered by the problems encountered in purification and analysis of EV-miRNAs [124,284], and of EVs themselves [285].…”

Mesenchymal Stem Cell Derived Extracellular Vesicles for Tissue Engineering and Regenerative Medicine Applications

“…Of course, this is not unique to MSC-EVs; there are many options but no standardised method for the isolation and purification of EVs. A world-wide survey by the International Society for Extracellular Vesicles (ISEV) [39], considering EV isolation from any and all sourced showed ultracentrifugation-based methods to be most commonly used, although a range of other approaches have been taken to overcome challenges regarding ultracentrifugation including the need for an ultracentrifuge, low-throughput of samples, and potential damage to EVs caused by high-speed centrifugation [40,41]. To this end, alternative methods such as filtration/ultrafiltration, size exclusion chromatography, immunoprecipitation, and precipitation with reagents such as PEG have been utilised, with varying degrees of efficacy in terms of purity and quantity [42].…”

Alphaherpesvirus gB Homologs Are Targeted to Extracellular Vesicles, but They Differentially Affect MHC Class II Molecules

“…The method used for isolation of vesicles is one of the critical factors that may affect the composition of EVs cargo [37]. We chose size exclusion chromatography (SEC), widely used in EVs research [28,38], to purify the vesicles from stable cell line supernatants.…”