Exosomes: Biological function, Clinical Potential & Utility

Louis A. Cona, MD
Updated on
May 23, 2023

Exosomes are particles that release naturally from a cell. These particles are responsible for cell to cell communication. These messenger cells have the ability to release growth factors and other beneficial processes.

Exosomes: Biological function, Clinical Potential & Utility

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Exosomes

Exosomes are messenger particles that release naturally from a cell. These particles are responsible for cell-to-cell communication. Exosomes carry genetic information and proteins to cells throughout your body, creating paths for communication between cells. These messenger cells can release growth factors and other beneficial processes.

Also known as extracellular vesicles (particles that release naturally from a cell that cannot replicate), they are responsible for cell-to-cell communication. Exosomes are released naturally from cells upon the fusion of a discontinuous closed membrane system, also known as the intermediate endocytic compartment. Although exosomes are roughly the same size (40-100 nm) as ectosomes, they are different species of vesicles.

When used in exosome treatment, these biomolecules can be specifically targeted to stimulate a desired response in the body. This innovative treatment has shown great promise in various medical applications, including cancer treatment, tissue repair, and immune modulation.

Suppose you are considering exosome treatment for a medical condition. In that case, it is important to research and consult a qualified healthcare professional to determine if this option is right for you.

What are exosomes?

Exosomes are tiny, single-membrane organelles of ∼30 to ∼200 nm diameter, released in high quantities from rapidly growing cells, including stem cells, t and b cells, and even cancer cells.

Exosomes contain an array of membrane-associated proteins, lipids, nucleic acids, and glycoconjugates and are believed to facilitate intercellular communication through the paracrine effect. Exosomes may also be used by stem cells to detect their environment and repair damaged tissue.  

Where are exosomes derived?

Exosomes are derived from cells in the body. Many cells produce and release them, including immune cells, t cells, tumor cells, cancer cells, dendritic cells, and neurons. Exosomes are formed within cells through exocytosis, during which the cell's endosomes (small, membrane-bound compartments within the cell) fuse with the cell membrane and release their contents into the extracellular space.

Once they are released into the extracellular space, exosomes can be taken up by other recipient cells and affect their functions. This process is thought to play a role in intercellular communication and is being investigated as a potential mechanism for the transfer of various molecules, including proteins, RNA, and DNA, between target cells.

Cell derived exosomes have been found to contain various types of molecules, such as proteins, lipids, and genetic material, that are specific to the cells that produced them. These exosomes can be taken up by other cells, even if they are far away from where the exosomes were released. When this happens, the molecules within the exosomes can alter the function of the recipient cells.

W‍hat is the biological function of exosomes?

Exosomes are thought to play a role in regulating complex intracellular pathways, and research has suggested that they may have a variety of functions in the body. Some studies have suggested that exosomes may be involved in the immune system's response to infection and the development and operation of the nervous system.

For example, exosomes have been shown to contain a variety of immune-related molecules, such as cytokines and antigens, and to be involved in the immune system's response to infection by influencing a recipient cell.

Exosomes have also been shown to be involved in the development and function of the nervous system. They have been found to contain a variety of molecules that are important for the development and maintenance of neurons, such as growth factors and signaling proteins. In addition, exosomes are involved in the communication between neurons and other cells in the nervous system.

Overall, the exact functions of exosomes are still being investigated, and more research is needed to understand their role in health and disease fully.

Research states that Exosomes are primarily messenger molecular mechanisms

According to a 2019 study published in the Cell and Bioscience Journal, Exosomes are nano-sized vesicles released into surrounding body fluids upon the fusion of multivesicular bodies and the plasma membrane. Extracellular vesicles derived from target cells were shown to carry cell-specific cargos of proteins, lipids, and genetic materials and can be selectively taken up by neighboring or distant cells far from their release, reprogramming the recipient cells upon their bioactive compounds. (3)

Exosome cell communication diagram
Exosome cell communication diagram

What is exosome therapy?

Exosome therapy involves using exosomes, small vesicles that are naturally produced by stem cells, to deliver therapeutic molecules to specific cells in the body. These exosomes contain a range of biomolecules, including proteins, nucleic acids, and lipids, that can be used to target specific cells and elicit a desired response. This is a new medical treatment that is being explored for a variety of potential applications.

Exosome therapy is gaining in popularity within the United States. Some doctors believe there may be benefits with the administration of exosomes, but there is minimal data proving safety and efficacy. This theory may have originated from studies that suggest the link between the health benefits of mesenchymal stem cells and exosomes. Exosomes are released naturally from mesenchymal stem cells, and MSCs have the highest amount of exosomes out of any cell.

These studies (outlined below) argue that exosomes may have therapeutic abilities, but researchers have found no conclusive evidence. There is also a regulatory concern about the legality of such treatments, especially when the exosome preparation protocol involves extraction from MSCs.

Why the increased interest in Exosome therapy?

According to a 2016 study conducted James R Edgar and colleagues, we could be seeing an increased interest for Exosome therapy for a few reasons:

  1. Exosomes are thought to provide a means of intercellular communication and transmission of macromolecules between cells
  2. Exosomes have been attributed roles in the spread of proteins, lipids, mRNA, miRNA, and DNA and as contributing factors in the development of several diseases
  3. Exosomes have been proposed to be useful vectors for drugs because they are composed of cell membranes rather than synthetic polymers, and as such, could be better tolerated by the host

What is the difference between stem cell therapy and exosomes?

Stem cells and exosomes are two distinct types of cells or cell products that are being studied for their potential use in medical treatments. Here are some key differences between the two:

  1. Origin: Stem cells are undifferentiated cells that have the ability to develop into a variety of specialized cell types. They are found in various tissues in the body and can be isolated and grown in the laboratory. Exosomes, on the other hand, are small, membrane-bound vesicles that are produced and released by cells in the body. They are formed within the cell through a process called exocytosis, during which the cell's endosomes (small, membrane-bound compartments within the cell) fuse with the cell membrane and release their contents into the extracellular space.
  2. Function: Stem cells have the ability to differentiate into a variety of specialized cell types and are being studied for their potential use in regenerative medicine. Exosomes, on the other hand, are thought to play a role in intercellular communication and have been proposed as potential mediators of various physiological and pathological processes. They have been found to contain a variety of biomolecules, including proteins, nucleic acids, and lipids, and to be involved in the transfer of these molecules between cells.
  3. Potential therapeutic applications: Stem cells are being studied for their potential use in a wide range of medical treatments, including the repair and regeneration of damaged tissues and organs. Exosomes, on the other hand, are being explored as a potential means of delivering therapeutic molecules to specific cells in the body. They have been proposed as a potential treatment for a variety of conditions, including cancer, neurodegenerative diseases, and cardiovascular disease.

Stem cells are a popular therapeutic tool promoting exosome secretion

Stem cell therapy has shown particular potential for the treatment of chronic inflammation, autoimmune disorders, fibromyalgia, degenerative diseases, and Lyme disease. These conditions are often characterized by inflammation, and exosomes have been found to have anti-inflammatory properties that make them a promising therapeutic option.

Exosomes are produced and released by many types of cells in the human body, including immune cells, cancer cells, and stem cells. While their role in intercellular communication is well established, the exact functions of exosomes are still not fully understood. Further research is needed to fully understand the role of exosomes in health and disease.

Overall, stem cells and exosomes are distinct types of donor cells or cell products that are being studied for their potential use in medical treatments. Stem cells have the ability to invoke a positive immune response, while dendritic cell derived exosomes act more as a messenger cell will lipid and protein composition.  

While stem cells have the ability to differentiate into various cell types and are being explored for their potential use in regenerative medicine, exosomes are thought to play a role in cell biology through intercellular communication and are being explored as a potential means of delivering therapeutic molecules to specific cells in the body.

Exosome release from mesenchymal stem cells upon administration

Mesenchymal stem cells (MSCs) are multipotent adult stem cells that can differentiate into various cell types and have the potential to regenerate damaged tissues. One of the critical mechanisms through which MSCs exert their regenerative and therapeutic effects is the secretion of exosomes.

Exosomes are naturally released from MSCs as part of their normal cellular functions. The process begins with forming multivesicular bodies (MVBs) inside the MSCs. MVBs are intracellular compartments containing numerous small vesicles, called intraluminal vesicles (ILVs), generated by the inward budding of the MVB membrane. These ILVs contain a diverse range of bioactive molecules, such as proteins, lipids, and RNA, which are selectively sorted and packaged into the ILVs by the MSCs.

Once the MVBs are fully formed, they are transported to the cell membrane, where they fuse with the plasma membrane, releasing the ILVs into the extracellular space. Upon their release, these ILVs are now called exosomes. This process is tightly regulated by various proteins and signaling pathways that control vesicle trafficking, membrane fusion, and cargo sorting.


Exosomes secreted by MSCs carry a unique set of molecules that reflect their origin and function. These molecules can include growth factors, cytokines, and various types of RNA, which can modulate the local cellular environment and promote tissue repair and regeneration. Upon administration of MSCs into damaged tissue or site of injury, the MSCs respond to local cues and secrete exosomes containing therapeutic cargo, which then interact with neighboring cells, influencing their behavior and promoting tissue healing and regeneration.

Understanding the mechanisms underlying exosome release from MSCs and the factors that influence their cargo composition is essential for harnessing the full therapeutic potential of MSC-derived exosomes in regenerative medicine and other clinical applications.

Exosomes therapy

Exosomes therapy is a new medical treatment that utilizes tiny vesicles called exosomes to deliver therapeutic molecules to specific cells in the body. These exosomes, which are naturally produced by stem cells, contain a variety of biomolecules including proteins, nucleic acids, and lipids that can be used to target specific cells and stimulate a desired response.

Exosomes therapy has shown promise in a wide range of medical applications, including cancer treatment, tissue repair, and immune modulation. It is an exciting area of research that has the potential to revolutionize the way we approach many diseases and conditions. If you are interested in learning more about exosomes therapy, it is important to do your research and consult with a qualified healthcare professional to determine if this treatment option is right for you.

"Exosomes have been found to have properties that allow them to regulate complex intracellular pathways, and this has led to the exploration of their potential use in the treatment of various diseases, including neurodegenerative conditions and cancer. Their ability to modify the activity of specific cells and pathways within the body makes exosomes a promising therapeutic option for a wide range of conditions."

Exosomes and stem cells

Mesenchymal stem cells (MSCs) can self-renew and can be isolated from various tissues. They have been tested widely in clinical trials due to their multitude of biological functions, including; differentiation, tissue repair, anti-inflammatory, and immunomodulatory properties. Exosomes derived from mesenchymal stem cells (MSCs), first investigated in a 2010 finding, showed that MSCs were able to produce higher amounts of exosomes than other cells. (2)

According to Zhang, exosomes are involved in cell to cell communication, and some researchers hypothesize that they are the paracrine effectors of MSCs.  Many types of cells secrete exosomes, including T and B cells, cancer cells, and stem cells. Although Exosomes are essential for cellular communication, their functions remain unknown.

Image of B cell and exosomes

Mesenchymal Stem Cells naturally secrete Exosomes

Mesenchymal stem cells may have the ability to repair tissue, modulate the immune system, and promote an anti-inflammatory response in patients. In an article published in the International Journal of Molecular Sciences, Zhang et al. state that “Several studies have reported that exosomes have functions similar to MSCs; however, the mechanisms are still not fully understood and remain controversial.” (2)

“Given the merits of MSCs, exosomes hold great promise as a controllable, manageable, and feasible approach in future studies. However, based on the proteomic and genomic complexities of exosomes, their possible mechanisms and exact compositions need further investigation.” Mesenchymal stem cells can produce prolific amounts of exosomes. Exosomes derived from mesenchymal stem cells have the potential to be used as a vehicle for drug or gene delivery or to facilitate cell therapy. (2) The study concluded that exosomes hold promise, but more studies are required before being able to consider using exosomes alone as a potential treatment option.

Exosomes therapies for anti-aging

Clinics in the United States are hailing exosome therapy for anti-aging as a new miracle cure. Some of these entities state that exosomes are more potent than MSCs at combating certain conditions. There are a few issues with these claims; firstly, there is a lack of data supporting the efficacy of exosomes without also introducing MSCs into the patient. Secondly, there are regulation concerns with exosomes in the United States that may promote the use of exosomes as a way of offering cell therapy while avoiding legal limitations set forth from the FDA. While there could potentially be some benefits with exosomes, they are still mostly understudied and unknown.

Exosome therapy and the FDA

Treatment with expanded MSCs is primarily not authorized by the FDA in the United States. These cells require approval from the FDA and require an Investigational New Drug Application (IND) submission. These regulations directly correlate with the rise in the popularity of exosome therapies. The regulatory environment in the United States and the disparity between different therapeutics can benefit clinics that market and administer exosomes because it may be easier to bypass the 4th criterion of 361 HCT/P’ S.

Methods of exosome isolation and purification

Exosomes, also called extracellular vesicles, are nanoparticles secreted by human cells that play a significant role in intercellular communication. Using different methods, they can be isolated and purified from various bodily fluids, such as blood, urine, and amniotic fluid. These methods include ultracentrifugation, size-exclusion chromatography, and immunoaffinity capture techniques. The purity and concentration of the extracted exosomes are critical factors to consider when manufacturing these nanoparticles for therapeutic applications.


Exosome-mediated drug delivery systems

Exosomes can be harnessed as drug delivery vehicles, as they can cross biological barriers, such as the blood-brain barrier, and deliver therapeutic cargo to target cells. This cutting-edge technology has been proven effective in treating several medical conditions, including cancers, neurodegenerative disorders, and rare diseases. However, scaling up the manufacturing process and ensuring the purity and safety of exosome-based therapeutics remains challenging.


Exosomes as potential biomarkers for disease diagnosis and Prognosis

Exosomes carry a wide range of bioactive molecules, such as proteins, lipids, and RNA, which can provide important information about the physiological state of the cells they originated from. This makes them promising biomarkers for the early detection and monitoring of various diseases, including breast cancer, cardiovascular diseases, and infectious diseases. However, further clinical trials and biologics evaluation are needed to validate the accuracy and effectiveness of exosome-based diagnostics.


Exosomes in the Context of Aging and age-related diseases

Aging is associated with changes in the composition and function of exosomes, which can influence tissue homeostasis and contribute to the progression of age-related diseases. Research has shown that exosomes derived from adult stem cells, such as human mesenchymal stem cells (hMSC), can promote tissue regeneration and Repair, modulate the immune system, and reduce inflammation. These findings suggest that exosome therapy could rejuvenate the body and combat age-related diseases.


Exosome cargo and its regulation

The cargo carried by exosomes, which includes proteins, lipids, and various types of RNA, is influenced by the cell type they are derived from and the physiological or pathological conditions of the parent cells. Researchers are currently working on understanding how exosome cargo is regulated and how it can be manipulated to develop more effective exosome-based therapeutics.


The role of exosomes in the pathogenesis of different diseases

Exosomes have been implicated in developing and progressing various diseases, such as cancer, neurodegenerative disorders, and infectious diseases. They can promote angiogenesis, immune evasion, and the spread of infection by transferring their cargo between cells. Understanding the role of exosomes in disease pathogenesis can help scientists develop new therapeutic strategies to target these tiny messengers and their signaling pathways.


Exosomes and their potential role in tissue regeneration and Repair

Exosomes derived from mesenchymal stem cells (MSC) have shown promise in promoting tissue regeneration and Repair in various injury models. Their cargo, including growth factors and mRNA, can stimulate new tissue growth, reduce scar tissue formation, and modulate the immune response to promote wound healing. This has potential applications in treating injuries and diseases affecting the skin, muscles, and nervous system.


Exosomes as a tool for understanding intercellular communication

As intercellular messengers, exosomes play a crucial role in cell-to-cell communication. Studying exosomes and their cargo can provide valuable insights into the molecular mechanisms underlying physiological processes and disease development. This knowledge can be used to develop targeted therapies and diagnostic tools based on exosome-mediated signaling.


Exosomes in the Context of infectious diseases

Exosomes can facilitate the spread of infectious diseases by transferring pathogenic cargo, such as viral proteins and nucleic acids, between host cells. They can also modulate the immune response to infection, promoting immune activation or evasion. Understanding the role of exosomes in the pathogenesis of infectious diseases can help researchers develop novel therapeutic strategies and vaccines to combat these infections.


The ethical considerations surrounding the use of exosomes in therapeutic applications

The use of exosomes in therapeutic applications raises several ethical considerations. These include ensuring the safety and efficacy of exosome-based therapies, protecting the rights and privacy of donors whose cells produce exosomes, and addressing potential inequalities in access to these cutting-edge treatments. Regulatory agencies, such as the FDA, play a crucial role in overseeing the development and approval of exosome-based therapies to ensure they meet safety and efficacy standards while addressing ethical concerns.

The Promising Future of Mesenchymal Stem Cells in Clinical Settings

In conclusion, the use of mesenchymal stem cells (MSCs) in clinical settings holds great promise due to their inherent regenerative and immunomodulatory properties. A significant aspect of MSCs' therapeutic potential lies in their ability to naturally release exosomes upon administration. These exosomes carry a unique set of bioactive molecules, such as growth factors, cytokines, and RNA, which can modulate the local cellular environment and promote tissue repair and regeneration.

The direct administration of MSCs leverages the full range of their therapeutic capabilities, including cell differentiation, paracrine signaling, and the release of exosomes. The use of MSCs in clinical settings can overcome some limitations associated with exosome-based therapies, such as challenges in large-scale production, purification, and standardization of exosomes.

The growing body of research on MSCs and their exosome secretion has demonstrated their therapeutic potential in a wide range of medical conditions, including tissue injuries, neurodegenerative disorders, autoimmune diseases, and infectious diseases. Moreover, MSCs offer several advantages, including their ability to home in on injured or inflamed tissues, and their capacity to modulate immune responses.

As our understanding of MSC biology, including exosome release and cargo regulation, continues to advance, it is anticipated that MSC-based therapies will play an increasingly important role in the clinical landscape. With further research and development, MSCs may soon become a cornerstone of regenerative medicine and a valuable tool for addressing various unmet medical needs, ultimately improving patient outcomes and quality of life.

References

(1) Edgar, James R. “Q&A: What Are Exosomes, Exactly?” BMC Biology, BioMed Central, 13 June 2016, https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-016-0268-z.

(2) Yu, Bo, et al. “Exosomes Derived from Mesenchymal Stem Cells.” International Journal of Molecular Sciences, vol. 15, no. 3, July 2014, pp. 4142–4157., doi:10.3390/ijms15034142.

(3) Zhang, Y., Liu, Y., Liu, H., & Tang, W. H. (2019, February 15). Exosomes: Biogenesis, biologic function and clinical potential - cell & bioscience. BioMed Central. Retrieved February 3, 2022, from https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-019-0282-2

(4) Pegtel DM, Gould SJ. Exosomes. Annu Rev Biochem. 2019 Jun 20;88:487-514. doi: 10.1146/annurev-biochem-013118-111902. PMID: 31220978.

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