Stem cell therapies have been developing and evolving rapidly over the last decade, and extracellular vesicles (EVs) are another innovative approach that researchers are exploring. EVs are being explored for their potential as the basis of new cell therapies, taking the signals generated from various types of stem cells and delivering just those signals, rather than the cells, to the patient.

So what are extracellular vesicles?

EVs are basically membrane-wrapped packages that contain proteins and other molecules and are created and released by cells. Nearby cells intercept these packages and adjust their behavior based on the information contained in the EVs.

Various names have been used to refer to the vesicles being released by healthy cells, including ectosomes, microparticles, and shedding microvesicles. For the purposes of discussion, we will use the term extracellular vesicles (EVs) as a generic term to describe all secreted vesicles.

EVs can broadly be described as either exosomes, microvesicles (MVs) or apoptotic bodies depending on their cellular origin:

Exosomes Microvesicles Apoptotic Bodies
Origin Endocytic pathway Plasma membrane Plasma membrane
Function Intercellular communication Intercellular communication Facilitate phagocytosis
Size 40-120 nm 50-1,000 nm 500-2,000 nm
Contents Proteins and nucleic acids (mRNA, miRNA and other non-coding RNAs) Proteins and nucleic acids (mRNA, miRNA and other non-coding RNAs) Nuclear fractions, cell organelles

Extracellular vesicles have attracted considerable interest in the scientific community due to their role in intercellular communication. It has been known for a long time that cells release vesicles into the extracellular environment during apoptosis. However, the fact that healthy cells also release vesicles into the extracellular environment has only been realized more recently.

A review of extracellular vesicles and aging

Today, we wanted to point out a great review paper discussing the potential of extracellular vesicles and how they could be used to develop new kinds of therapies[1].

It is not hard to imagine that stem cell therapies could evolve to include therapies that use cellular signals without any actual cells being transferred. Indeed, we have seen some studies showing that even cell culture that has had stem cells kept in it retains some beneficial properties that can help facilitate healing.

The clinical data thus far strongly supports that many cell therapies produce beneficial effects via this signaling. Mesenchymal stem cells are a classic example; the cells themselves do not survive in the patient for long, but the signals they give off encourage tissue repair.


It is logical that therapies based on just these signals are the next step forward, though they would not totally replace whole-cell therapies. It is important that we develop efficient ways to transplant stem cells and improve their survival and engraftment rates to deal with organ failure. This will improve with time, and, indeed, progress on this front has been rapid in recent years.

Meanwhile, we can consider the use of extracellular vesicles as yet another string on our bow and an option for therapy in certain cases.


[1] Robbins, P. D. (2017). Extracellular vesicles and aging. Stem Cell Investigation, 4(12).

About the author

Steve Hill

Steve serves on the LEAF Board of Directors and is the Editor in Chief, coordinating the daily news articles and social media content of the organization. He is an active journalist in the aging research and biotechnology field and has to date written over 500 articles on the topic as well as attending various medical industry conferences. In 2019 he was listed in the top 100 journalists covering biomedicine and longevity research in the industry report – Top-100 Journalists covering advanced biomedicine and longevity created by the Aging Analytics Agency. His work has been featured in H+ magazine, Psychology Today, Singularity Weblog, Standpoint Magazine, and, Keep me Prime, and New Economy Magazine. Steve has a background in project management and administration which has helped him to build a united team for effective fundraising and content creation, while his additional knowledge of biology and statistical data analysis allows him to carefully assess and coordinate the scientific groups involved in the project. In 2015 he led the Major Mouse Testing Program (MMTP) for the International Longevity Alliance and in 2016 helped the team of the SENS Research Foundation to reach their goal for the OncoSENS campaign for cancer research.
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