brain cancer, extracellular vesicles, nanoparticle tracking analysis, sialic acid http://creativecommons.org/licenses/by-nc-nd/4.0/legalcode Srpsko društvo istraživača raka eng info:eu-repo/semantics/conferenceProceedings Background: Cerebrospinal fluid (CSF) is a clear fluid with low protein content, widely used for both diagnostic and prognostic purposes. Although extracellular vesicles (EVs), small particles with a bilayer membrane, are present in CSF, data regarding their properties remain scarce. In this study, EVs were isolated from CSF of subjects with nonmalignant (hydrocephalus) and malignant (medulloblastoma/ependymoma) neurological disorders to compare their concentration, size distribution, and surface presence of sialic acid-containing glycans. This study aims to provide preliminary data on the potential of basic CSF EVs properties as discriminating markers. Material and Methods: EVs were isolated from pooled CSF samples of subjects with non-malignant (nmEVs) and malignant (mEVs) neurological disorders by differential centrifugation. Fluorescently labeled sialic acid-binding plant lectins: wheat germ agglutinin (WGA) and Sambucus nigra agglutinin (SNA) were used in nanoparticle tracking analysis (NTA) to assess EVs surface sialylation. The presence of tetraspanins, commonly used as EVs markers, was evaluatedusing antibodies against CD9, CD81, and CD63. Results: Higher concentration of mEVs (1.08×10¹¹ particles/mL) compared to nmEVs (1.50×10¹⁰ particles/mL) was revealed. Size distribution showed that the majority of EVs in both subject groups fell within the 100-200 nm range. The share of CD9-positive EVs was five times higher in nmEVs compared to mEVs, while the share of CD81-positive EVs did not differ notably between the two groups. Anti-CD63 antibody exhibited minimal reactivity to both nmEVs and mEVs. The share of WGA-reactive EVs was similar between nmEVs and mEVs, whereas the share of SNA-reactive EVs was over three times higher in mEVs. Conclusions: An increased share of SNA-reactive mEVs, indicating changes in sialylation, was found. In addition, a reduced share of CD9-positive mEVs was observed. Alterations in basic CSF EVs properties may serve as potential markers of their origin. https://phaidrabg.bg.ac.rs/o:36913 ISSN: 3009-3848 Basic properties of extracellular vesicles from cerebrospinal fluid of subjects with non-malignant and malignant neurological disorders Mitić, Ninoslav Janjić, Filip Goč, Sanja Janković, Tamara Janković, Miroslava Vujotić, Ljiljana Basic properties of extracellular vesicles from cerebrospinal fluid of subjects with non-malignant and malignant neurological disorders 2025 application/pdf 1955071 bytes