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November 19, 2019 - Accurate EV Quantification

Spectradyne was pleased to participate in the inaugural event of the Extracellular Vesicle (EV) Working Group on October 29, 2019 at the Research Institute of the McGill University Health Centre (RI-MUHC) in Montreal, Canada. We would like to thank our hosts, Dr. Janusz Rak and Dr. Peter Metrakos of McGill for the invitation to sponsor, and for assembling a group of scientists advancing such exciting work in the field of extracellular vesicles from across Quebec.

One special aspect of this meeting was that the organizers intentionally and successfully created a we're-all-still-learning atmosphere that allowed scientists that are new to extracellular vesicle research to present their work to an open-minded audience. This environment allowed for creative and supportive discussion between the more experienced EV researchers and the newly minted ones, and also provided a safe space for discussing areas of disagreement.

In fact, a 30-minute panel discussion chaired by Dr. Rak was included in the morning agenda to discuss controversies in the field-and as a new and rapidly expanding field, extracellular vesicle research turned out to have more than 30 minutes' worth of controversies to talk about!

One fire-starting topic that Spectradyne has spoken on at many venues, including in this blog, and is always happy to discuss more, is the importance of using orthogonal methods to quantify extracellular vesicles. Now, because the Minimal Information for Studies of Extracellular Vesicles 2018 (MISEV 2018) guidelines clearly require using at least two techniques to quantify vesicles, you might not think this would be such a hot-button issue. However, relying on a single method such as Nanoparticle Tracking Analysis (NTA) to quantify extracellular vesicles is still commonplace in the field. And despite a growing awareness of its critical limitations, many researchers are still surprised when they find out that Nanoparticle Tracking Analysis is in fact grossly misrepresenting the content of their samples.

Why does accurate quantification of extracellular vesicles matter?

Here's an example: Suppose a researcher would like to compare the therapeutic effect of EVs or other nanoparticles such as liposomes or gene therapy vectors that have been prepared with different methods. Each therapeutic agent is to be applied to a biological replicate of a test system (e.g., cultured cells) and the response of that system is to be quantified by measuring certain parameters such as viability, cell morphology, differentiation activity, or other indicator. What scientist, given the technology to do so, would consider performing such an experiment without first measuring the dose of each product that was applied? Without controlling for the quantity of therapeutics agent applied to the test system, important differences between the effectiveness of the different preparations may remain hidden by excess variability.

No matter the downstream measurement, extracellular vesicle concentration is always a critical experimental variable and must be carefully controlled to ensure clear experimental outcomes. Learn more about how our technology delivers this ability here.

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