Cryo-Electron Microscopy Demonstrates Polymorphism of Small Extracellular Vesicles

In this study, the computer program Veronica was created – a specialized environment for marking images obtained by cryo-electron microscopy. It allows to highlight the contours of closed and unclosed objects and save them in a convenient format for analysis, as well as to determine the specified metrics for the study of morphology. The Veronica program was used to characterize the morphology of samples of small extracellular vesicles isolated from gastric juice of patients with gastric adenocarcinoma and conditionally healthy donors. We proposed an approach to image annotation and calculation of indices to describe vesicles based on the measurement of nesting (a measure of the number of particles nested within each other) and branching (a measure of the number of adjacent particles surrounded by a common membrane) parameters.