Extracellular vesicles (EVs) are gaining increased importance in fundamental research as key players in disease pathogenic mechanisms, but also in translational and clinical research due to their value in biomarker discovery, either for diagnostics and/or therapeutics. In the first research scenario, the study of EVs isolated from neuronal models mimicking neurodegenerative diseases can open new avenues to better understand the pathological mechanisms underlying these conditions or to identify novel molecular targets for diagnosis and/or therapeutics. In the second research scenario, the easy availability of EVs in body fluids and the specificity of their cargo, which can reflect the cell of origin or disease profiles, turn these into attractive diagnostic tools. EVs with exosome‐like characteristics, circulating in the bloodstream and other peripheral biofluids, constitute a non‐invasive and rapid alternative to study several conditions, including brain‐related disorders. In both cases, several EVs isolation methods are already available, but each neuronal model or biofluid presents its own challenges. Herein, a literature overview on EVs isolation methodologies from distinct neuronal models (cellular culture and brain tissue) and body fluids (serum, plasma, cerebrospinal fluid, urine and saliva) was carried out. Focus was given to approaches employed in the context of Alzheimer's and Parkinson's diseases, and the main research findings discussed. The topics here revised will facilitate the choice of EVs isolation methodologies and potentially prompt new discoveries in EVs research and in the neurodegenerative diseases field. image

The potential of exosomes as biomarker resources for diagnostics and even for therapeutics has intensified research in the field, including in the context of Alzheimer´s disease (AD). The search for disease biomarkers in peripheral biofluids is advancing mainly due to the easy access it offers. In the study presented here, emphasis was given to the bioinformatic identification of putative exosomal candidates for AD. The exosomal proteomes of cerebrospinal fluid (CSF), serum and plasma, were obtained from three databases (ExoCarta, EVpedia and Vesiclepedia), and complemented with additional exosomal proteins already associated with AD but not found in the databases. The final biofluids’ proteomes were submitted to gene ontology (GO) enrichment analysis and the exosomal Aβ-binding proteins that can constitute putative candidates were identified. Among these candidates, gelsolin, a protein known to be involved in inhibiting Abeta fibril formation, was identified, and it was tested in human samples. The levels of this Aβ-binding protein, with anti-amyloidogenic properties, were assessed in serum-derived exosomes isolated from controls and individuals with dementia, including AD cases, and revealed altered expression patterns. Identification of potential peripheral biomarker candidates for AD may be useful, not only for early disease diagnosis but also in drug trials and to monitor disease progression, allowing for a timely therapeutic intervention, which will positively impact the patient’s quality of life.

Alzheimer’s disease is a challenge in modern healthcare due to its complex etiology and increasing prevalence. Despite advances, further understanding of Alzheimer’s disease pathophysiology is needed, particularly the role of Aβ neurotoxic peptide. Fourier transform infrared spectroscopy (FTIR) has shown potential as a screening tool for several pathologies, including Alzheimer’s disease. Nonetheless, limited research has explored Aβ direct effects on neurons and extracellular vesicles metabolic profiles. Hence, this study aims to investigate Aβ impact on the spectroscopic profiles of neuronal-like cells (N2a) and N2a-derived extracellular vesicles, employing FTIR spectroscopy and focusing on the 1280–900 cm⁻¹ region. A comprehensive analysis of spectral data was carried out, including multivariate partial least squares (PLS) analysis and peak intensities analysis. PLS analysis revealed moderate to strong correlations within this spectral region for both N2a and N2a-derived extracellular vesicles. The peak intensity analysis revealed additional peaks with significant differences in EVs’ spectra relative to N2a, following Aβ treatment. Specifically, Aβ seems to cause alterations in protein phosphorylation and in the nucleic acids content of extracellular vesicles. These findings support that Aβ’s role in Alzheimer’s disease pathology may be mediated by extracellular vesicles and highlight FTIR’s potential for advancing Alzheimer’s disease research and clinical applications.