Science of Exosomes

Exosomes are progressively known as significant mediators of cell-to-cell communication and have a positive effect on reducing inflammation and promoting tissue healing and regeneration.

They convey active biomolecules to target cells and have vital functions in several physiological and pathological processes, and show substantial promise as novel treatment strategies for diseases.

What are Exosomes?

Exosomes are a category of extracellular vesicles (EVs) produced in the endosomal compartment of eukaryotic cells that have specialized functions in physiological processes, including coagulation, cell waste management and intercellular communication, where they are believed to be mediators of inflammation and cell growth.

EV's are released by many different cell types, participating in different physiological and or pathological processes. Depending on their origin, they can alter the fate of recipient cells according to the information transferred.

Exosomes have a size range of ~40 to 160 nm in diameter (a human hair is 60,000 nm in width). Their “cargo” is very cell-specific, loaded with microRNAs (miRNA) and >300 other bioactive contents including DNA, RNA, lipids, metabolites, and cell-surface proteins.

Research Publication

The Messengers

Extracellular vesicles (EV’s) consist of exosomes and other nanoparticles, which are released directly from the cell membrane. EV’s can mediate cell–cell communication and are involved in many processes, including immune signaling, angiogenesis, stress response, senescence, proliferation, and cell differentiation.

EV’s are involved in restoring tissue and organ damage, and may partially explain the paracrine effects observed in stem cell-based therapeutic approaches. The function and content of EV’s may also harbor information that can be used in tissue engineering, in which paracrine signaling is employed to modulate cell recruitment, differentiation, and proliferation. (1)

Growth Factors & Cytokines

Growth factors are proteins that may act locally or systemically to affect the growth of cells in several ways. Various cell activities, including division, are influenced by growth factors.

Cytokines are small proteins that are crucial in controlling the growth and activity of other immune system cells and blood cells. When released, they signal the immune system to do its job. Cytokines affect the growth of all blood cells and are responsible for regulating the immune response, inflammation, tissue remodeling and cellular differentiation.

Paracrine signaling is a form of cell-to-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior of those cells. Signaling molecules known as paracrine factors diffuse over a relatively short distance (local action), as opposed to endocrine factors (hormones which travel considerably longer distances via the circulatory system), juxtacrine interactions, and autocrine signaling.(3)

(1) Extracellular Vesicles: Potential Roles in Regenerative Medicine Olivier G. De Jong, Bas W. M. Van Balkom, Raymond M. Schiffelers, Carlijn V. C. Bouten, Marianne C. Verhaar. Front Immunol. 2014; 5: 608.
(2) Effie Ioannidou, “ Therapeutic Modulation of Growth Factors and Cytokines in Regenerative Medicine”, Current Pharmaceutical Design (2006) 12: 2397.
(3) U.S. National Library of Medicine, G04.085.600, Paracrine Communication, Cellular signaling in which a factor secreted by a cell affects other cells in the local environment.