Due to the recent and extremely fast expansion of the EV field, the used isolation and characterization methods are variable, or they are non-existent e.g. separation of exosomes and microvesicles. Furthermore, misconceptions and methodological pitfalls hamper the progress in understanding the biological function of EVs. To improve the reliability and credibility of the reported findings, several methodological aspects needs to be addressed. There are three sources of variation that affect the outcome of EV measurements: 1) the sample itself (e.g. body fluid), 2) the pre-analytical phase (e.g. sample collection, handling, storage, EV isolation and purification), 3) the analytics (e.g. the hardware, and software used to detect EVs and analyze the obtained results). The scientific community increasingly recognizes the need to standardize methodology and technology, which has lead to launching many international standardization initiatives such as ISEV guidelines about the minimal information for studies of EVs (MISEV), EV-TRACK promoting transparent reporting and centralizing knowledge, and the EV Flow Cytometry Working Group initiated by ISAC (International Society for Advanced Sciences), ISEV and ISTH (International Society for Thrombosis). EV group has for long actively taken part in methodological development and standardization in the EV field e.g. MISEV and ISEV Rigor and Standardisation (Blood work group).
METVES II
In 2019-2022 EV group participates in METVES II: Standardisation of concentration measurements of EVs for medical diagnoses, an EU –wide project, which aims to tap to the clinical potential of EVs by developing traceable measurements of number concentration, size distribution, refractive index and fluorescence intensity of cell-specific EVs in human blood and urine. In METVES II, EV group develops ready-to-use biological test samples from human urine, which will be evaluated in an inter-laboratory comparison study across a range of standard flow cytometers in clinical labs.
EVE consortium
The EV group belongs to the Business Finland –funded consortium EVE –Extracellular Vesicle (EV) Ecosystem for Theranostic Platforms which brings together 13 Finnish academy and industry partners to drive the development of novel EV-based therapeutic and diagnostic solutions. In EVE, the EV group specifically addresses the therapeutic potential of platelet-derived EVs in close collaboration with the R&D of Finnish Red Cross Blood Service (FRCBS). For identification of the true clinical potential of EVs, the development of improved EV methodologies is a fundamental part of the EVE project. The EV group sets up, optimizes, and develops further several state-of-the-art technologies for EV assessment enabling orthogonal approaches, and develops protocols and guidelines for EV handling, storage, methodologies and analyses. The method development work is done in close collaboration with other EVE consortium partners such as FRCBS, VTT, and the groups of Tapani Viitala (UH) and Elina Vuorima-Laukkanen (TaU) and is further advanced through international collaboration with other EV initiatives in EU (e.g. METVES II), research organisations, and companies.
Also, issues relating to the small sample size and large number of samples, such as in cohort/biobank samples, need to be resolved. We address these issues as we progress within the individual research projects, but we also target these issues directly in the EV core where the EV group collaborates with Dr. Maija Puhka in the Finnish Institute of Molecular Medicine (FIMM).
Highlighted publications
