The “Gold Standard Trial” was carried out by a consortium composed of the following research institutions: Aalborg University Hospital, Denmark; The Academic Medical Center, the Netherlands; Utrecht University, the Netherlands; University of Melbourne, Australia; Duke University, School of Medicine USA and Semmelweiss University, Hungary. The aim of this large scale EV trial, facilitated by Izon Science was to show that EV separation and measurement is feasible and comparable results can be achieved. The tests were conducted on identical plasma samples, and the protocol followed included EV isolation using qEV columns and particle characterisation of concentration using a qNano instrument. The results of this trial were presented by Dr Shona Pedersen of Aalborg University Hospital at ISEV 2015. The abstract of the talk is given below.
Recently, novel platforms for the detection of extracellular vesicles (EVs) have emerged but clinical evaluations of these new technologies are lacking. To promote effective research of EVs, a crucial pre-requisite is the ability to compare work across different groups using optimized and standardized methods of characterization, analysis and reporting. We report on the results of such a methodology being developed to allow consistent analysis of vesicles isolated from plasma and other complex body fluids.
The isolation method is based on size exclusion chromatography (SEC) which is gentle and takes less than 20 minutes. The characterization technique used is Tunable Resistive Pulse Sensing (TRPS), as it is possible to standardize operation to provide repeatable measurements across a defined size range and analyze concentration over a defined population size-range.
The protocols have been tested using a liposome control and citrated plasma sample measured by 7 groups. Each group will perform 5 measurements to demonstrate the reproducibility across SEC isolation, TRPS measurement and users. Preliminary evaluation of the liposome model across users showed that the TRPS method was capable of 40% coefficient of variation (CV). An improved protocol that mitigates the variation of the nanopore and biological sample interactions has been developed and tested using a double blind study involving 8 participants where a CV of 30% was calculated.
Accurate, high-resolution characterization of EVs is critical to understanding their properties, function and potential use as predictive markers or therapeutic agents. Isolating EVs using SEC combined with TRPS as high-resolution particle-by-particle analysis technique can provide much needed detail to better understand the use of EVs. We have presented results of this standard measurement protocol that allows for comparable characterization, analysis and reporting of clinical samples.