Detection and Isolation of Tissue-Specific Extracellular Vesicles From the Blood

Abstract

Extracellular vesicles (EVs) are nanosized, membrane-bound particles released by virtually all cell types, serving as messengers within tissues and across organs via the bloodstream. EVs encapsulate diverse molecular cargo that reflects the phenotypic state of their originating cells, making them promising candidates for liquid biopsy applications. However, the heterogeneity of circulating EVs, comprising particles from various cell types and non-vesicular entities like lipoproteins, poses significant challenges for isolating tissue-specific EV populations. This review examines current methodologies for detecting and isolating tissue-specific EVs from blood, focusing on immunoaffinity capture (IAC) strategies that leverage surface marker expression for specificity. Key considerations, including the selection and validation of markers, are discussed alongside advances in EV subtyping and isolation protocols. Challenges such as marker cross-reactivity, EV biogenesis and transport dynamics are highlighted to underscore the complexity of achieving clinical utility. By providing an overview of validated tissue-specific markers and isolation techniques, this review aims to facilitate the development of EV-based biomarkers with enhanced specificity and sensitivity, enabling minimally invasive monitoring of organ function and disease.

Keywords: EV subtypes; cell origin; extracellular vesicles; immunoaffinity isolation; organ‐derived; tissue‐specific.

FIGURE 1

Circulating extracellular vesicles are derived from multiple origins. EVs from solid tissues represent a minor fraction among contaminant particles, including EVs from non‐target cell types, especially haematopoietic cells, albumin, lipoproteins and other abundant plasma proteins. Immunoaffinity detection or capture (IAC) methods can be used to selectively analyse target EVs based on surface marker expression. IAC confers critical benefits to liquid biopsy applications due to (i) removal of signal for a marker of interest from alternate tissue sources (enhances specificity) and (ii) greater depletion of abundant contaminants that supress signal for the marker (enhances sensitivity).