Exosomes – a new field arising from the cell therapy industry

Exosome technology

Exosomes defined

Exosomes are nano-sized vesicles secreted from different cell types that contain various biomolecules, such as proteins and nucleic acids. They are enveloped in a lipid bilayer membrane, reflecting their origination from endocytic (intracellular) compartments, and range from 30–150 nm in diameter.

Exosomes are best defined as extracellular vesicles that are released from cells upon fusion of an intermediate endocytic compartment, the multivesicular body (MVB), with the plasma membrane.

Exosomes as therapeutics

Exosomes are nano-size lipid-bilayer containing structures that are naturally secreted by cells. Exosomes contain proteins, nucleic acids, and lipids that can be transferred from the producer cells to the target cells inducing the latter’s response.

Numerous pre-clinical and clinical data in several disease models have shown that exosomes derived from human mesenchymal stromal cells (MSCs) have significant anti-inflammatory, immunomodulatory, anti-fibrotic, and anti-oxidative capacities.

Exosomes as drug delivery vehicles

Exosomes display tropism and homing characteristics. They do not possess the key disadvantages of their parental cells i.e., low stability, viability issues, tumor formation and immune rejection risk. Therefore, exosomes can be used as a delivery tool for various drug substances, so called “cargoes” like nucleic acids, proteins, small molecules, pharmaceutical drugs, etc., to target cells, tissues, and organs of interest.

Exosomes protect cargoes from degrading enzymes and the immune system during circulation in the body on their way to the target. The exosome surface can be modified to improve or change the targeted delivery of cargoes.