A pilot study of plasma-derived extracellular vesicles isolated by EXODUS for tumor diagnosis

Extracellular vesicles (EVs) are emerging as biomarkers with diagnostic potential for tumors, yet EV isolation from plasma remains challenging. In this study, the efficacy of EXODUS for isolating EVs from plasma was evaluated, and the association of these EVs with clinical parameters in patients with glioma and pulmonary tumors were explored.

Plasma EVs were isolated from 19 patients with glioma, 25 patients with pulmonary tumors, and 16 healthy control individuals using EXODUS. Briefly, EVs were analyzed and confirmed by nanoparticle tracking analysis, transmission electron microscopy, and Western blotting (CD9/Flotillin-1/Alix). In addition, the associations between plasma EVs and clinical measurements, such as biochemical, hematologic, and inflammatory indicators, were examined by Pearson or Spearman tests.

EXODUS was used to isolate EVs of comparable sizes (30-150 nm) across groups from 400 µL plasma. Extracellular vesicle concentrations were much higher in plasma from patients with gliomas and pulmonary tumors than in healthy control samples. The EV protein levels followed similar trends. Plasma EV concentrations strongly correlated with triglyceride levels in patients with gliomas, whereas EV protein levels were negatively correlated with albumin levels in pulmonary tumor/healthy control samples. Compared with blood-based inflammatory markers, EV proteins demonstrated superior diagnostic performance.

Our results show that EXODUS is an effective method for isolating EVs from plasma. In this pilot study, an initial investigation of plasma EVs was performed as an auxiliary indicator in cancers for potential clinical application. Plasma EVs with sufficient yield and purity will pave the way for further functional analyses, including proteomics.