Extracellular vesicles

Extracellular vesicles (EVs) are small membrane vesicles secreted by most cells, containing proteins, lipids and nucleic acids. Based on their biogenesis pathways and size range, EVs are generally categorized into three types, including exosomes, apoptotic bodies and microvesicles. With a size rage of 40-100 nm and endocytic origin, exosomes are secreted by various cell types, including red blood cells, platelets, lymphocytes, dendritic cells, epithelial cells, adipocytes, fibroblasts, neural cells, stem cells and tumor cells 1. They also commonly appear in biological fluids such as urine, breast milk, plasma, amniotic fluid, malignant ascites, saliva 2, synovial fluid, bronchoalveolar lavage fluid and cerebrospinal fluid (CSF) 1. This highlights their important role in physiological and pathological processes of signaling pathways, cell-to-cell communication, immunomodulatory functions, antigen presenting in some cells, tumor progression, coagulation, inflammation and transferring macro molecules such as proteins and RNA 1,3.