Abstract: Extracellular vesicles (EVs) are heterogeneous nano-sized vesicles of endocytic origin shed into blood and other body fluids such as urine, saliva, seminal fluid, ascites, amniotic liquid, synovial fluid, breast milk and cerebrospinal fluid (CSF) by quite all cell types. EVs actively contribute to intercellular communication as they carry bioactive molecules that are selectively incorporated by the originating cell and are delivered to recipient cells over long and short distances (Simons and Raposo, 2009). EVs can be divided into three main groups according to their size and cellular origin: 1) exosomes (40–120 nm), that have an endocytic origin and are formed by inward budding of the limiting membrane of multivescicular bodies, which fuse with the plasma membrane and release exosomes into the extracellular space; 2) microvesicles (50–1000 nm), budding directly off the plasma membrane; 3) apoptotic bodies (> 1000 nm), which are released during apoptosis. Besides originating via distinct processes, different subtypes of EVs carry different proteins within their membrane and luminal compartments that reflect the phenotype of the tissue of origin.