A Size-Exclusion Chromatography-Based Procedure for Isolating Extracellular Vesicle Subsets from Porcine Seminal Plasma

Extracellular vesicles (EVs), membrane nanoparticles (30-to-1000 nm diameter) secreted and released by most of the body functional cells, have emerged as powerful cell-to-cell messengers transferring their bioactive cargo (proteins, lipids, and nucleic acids) from donor to recipient cells. The promising potential utility of EVs as both noninvasive biomarkers and therapeutic carriers for several pathologies, including some types of cancers, has attracted increasing scientific interest. EVs can be found in all body biofluids, including seminal plasma, a complex fluid consisting mainly of a mixture of secretions of the epididymis and accessory sex glands. Seminal EVs are involved in modulating both sperm physiological processes and immune environment of the internal female genital tract, thus playing an essential indirect role in fertilization and embryo development. Seminal plasma, alike other biofluids, contains a heterogenous population of EV-subsets. However, the lack of consensus on the most accurate procedure for isolating EV-subsets has led to a poor definition of their composition/function. Currently, size exclusion chromatography (SEC), a size-selective separation method, is one of the most promising EV-isolation procedures, allowing the isolation of EVs from biological fluids in a purer, easier, cheaper, and more scalable way compared to other alternative isolation procedures. This chapter reports a SEC-based protocol, combined with differential centrifugation and ultrafiltration, to isolate two subsets of seminal EVs differing in size (large and small EVs) in the ejaculate of pigs, a livestock species of great productive interest and an outstanding animal model for human reproduction.