Overview of Exosomes

Exosomes are vesicles released extracellularly by eukaryotic cells when a multivesicular body fuses with the plasma membrane. They range from 40 to 160 nanometers in diameter.

When released, exosomes send signals to other cells to induce specific responses. They maintain cellular homeostasis, elicit immune responses, and promote or prevent diseases, depending on their tissue of origin and the molecules they contain.

Exosomes may contain a variety of molecules, such as proteins, nucleic acids, lipids, or metabolites. For example, leukocyte-derived exosomes contain interferon-alpha, which prevents viral infection by suppressing the multiplication of the virus.

Since exosomes are intercellular communicators displaying a wide range of functions, they are being explored as therapeutic agents to deliver molecules to specific cellular targets.

Exosomes are also found in body fluids, including plasma, amniotic fluid, semen, and urine. Body-fluid-derived exosomes may contain biomarkers for specific diseases and are being investigated as potential diagnostic agents.

For example, a biomarker for Alzheimer's disease is present at high levels in the exosomes derived from cerebrospinal fluids of affected patients.