Exosomes are membranous extracellular vesicles with a size of 30-150 nm that are secreted by almost all cell types. They were originally thought to be cellular waste products, but have since been shown to play an essential role in intercellular communication . They transport proteins, lipids and RNA and regulate numerous physiological processes, including immune responses, tissue regeneration and metabolic regulation.
Due to their versatile functions, exosomes are increasingly becoming the focus of biomedical research, particularly with regard to their potential application in regenerative medicine, diagnostics and targeted drug delivery, including in dietary supplements. In this article, we look at how exosomes work and take a closer look at their opportunities and possibilities.
Biogenesis and function of exosomes
Exosomes are formed within the cell via a specific sequence of intracellular processes:
Formation of multivesicular endosomes (MVEs)
In our cells there are small "factories" called endosomes. Even smaller "packets" called exosomes are produced in these endosomes. You can imagine it like when you squeeze an air bubble and a new, small bubble is created inside.
There are two ways in which these exosomes are formed:
- With the help of a "sorting team": a complex system of proteins called ESCRT helps to shape the exosomes neatly.
- In another, as yet unknown way: There are also mechanisms that work independently of ESCRT - but these are not yet fully understood.
When the endosome is full of these little packets of exosomes, we call it a multivesicular endosome (MVE). Imagine the MVE is like a sack full of little messages. This sack then fuses with the cell wall and opens outwards, releasing the exosomes. These exosomes then float around the body and transmit messages to other cells as messenger substances.
Exocytosis of exosomes
The MVEs (the "sacs" full of exosomes) fuse with the cell wall, releasing the exosomes into the space outside the cell.
Interaction with target cells
Exosomes are small packages with important information. When they dock onto other cells or are taken up by them, they release their molecular content. This content can change the function of the cell by triggering certain signaling pathways or leading to changes in the tissue. The exosomes therefore act like small regulators of cell activity.
Regulation by microRNAs (miRNAs)
Exosomes transport a variety of microRNAs that can specifically enter target cells and regulate gene expression. These miRNAs can either inhibit or stimulate the production of certain proteins. (Learn more about this in the article on proteomics) This has significant effects on cellular processes such as inflammation, tissue regeneration and cell protection.
For example, certain miRNAs in exosomes have been shown to suppress inflammatory signaling pathways and activate repair mechanisms in damaged tissues. Cancer research is investigating how exosomal miRNAs influence tumor progression and whether they can be used as a targeted therapy option.
Comparison of plant and human exosomes
Both animal and plant cells produce exosomes, but they differ in their molecular composition and potential applications:
| Eigenschaft | Menschliche Exosomen | Pflanzliche Exosomen |
| Ursprung | Stem cells, immune cells, epithelial cells | Plant cells (fruit, vegetables, herbs) |
| Funktion | Immunomodulation, tissue regeneration, signal transduction | Antioxidant, anti-inflammatory properties |
| Zusammensetzung | Proteins, microRNAs, lipids | Polyphenols, plant RNA |
| Stabilität | Relative instability in the digestive tract | High stability and bioavailability |
While human exosomes are being researched for personalized therapies, plant exosomes have great potential as natural food supplements. Studies show that they can have anti-inflammatory effects and possibly influence the intestinal microbiome . Plant exosomes from grapes or broccoli contain bioactive molecules that could act as prebiotic substances.
Potential of exosomes for longevity and barriers to implementation
Exosomes could also play a very important role in longevity research due to the properties described above, especially in the following areas:
- Cellular senescence: Cellular senescence refers to a state in which cells irreversibly withdraw from the cell cycle. Exosomes could contribute to the elimination or reactivation of senescent cells and thus slow down the ageing process.
- Mitochondrial function: Exosomes could specifically correct mitochondrial dysfunction , which plays a key role in age-related diseases.
- Immune regulation: By modulating the immune system, exosomes could inhibit chronic inflammatory processes that contribute to age-related diseases.
- Neurodegenerative diseases: Exosomes show promise in the treatment of Alzheimer's and Parkinson's disease, as they may promote neuronal regeneration .
Find out more about the molecular basis of the ageing process in the Hallmarks of Aging.
Why are exosomes not yet being used more widely?
Despite their enormous potential, there are several challenges that currently limit the widespread use of exosomes in longevity medicine:
- Lack of standardization: The production and characterization of exosomes is complex and requires standardized protocols that are not yet fully established.
- Regulatory hurdles: The legal classification of exosomes as medicinal products or food supplements is unclear, which makes market entry difficult. In addition, non-herbal exosome therapies are not yet approved within the EU.
- Insufficient clinical studies: Many studies are still at the preclinical stage and long-term data on safety and efficacy are lacking.
- Ethical issues: There are ethical concerns regarding the derivation and use of exosomes from human stem cells in particular.
Despite these challenges, continued research on exosomes will lead to them playing a key role in longevity research and personalized medicine in the coming years. Advances in biotechnology, optimized manufacturing processes and regulatory clarity are likely to pave the way.
Regulatory framework for exosomes in the EU
The legal classification of exosomes varies depending on the area of application:
- Pharmaceuticals: Human exosomes are subject to the EMA's Advanced Therapy Medicinal Products (ATMPs) Regulation and require a comprehensive clinical trial.
- Food supplements: Plant exosomes could fall under the Novel Food Regulation (EU Regulation 2015/2283) if they constitute a novel ingredient.
- Cosmetic products: Exosome-based skin care must comply with the EU Cosmetics Regulation (EC) 1223/2009), with corresponding studies on safety and efficacy.
Exosomes in existing products and markets
Exosomes are already commercially available in various industries and have established themselves in certain areas:
Kosmetische Anwendungen
Skin care products containing exosomes are marketed by various brands as an anti-aging solution. These products contain exosomes, which are said to stimulate collagen production and support skin regeneration. Some dermatological treatments also use exosomes to accelerate skin rejuvenation and wound healing.
Regenerative Medizin
In clinical studies, exosomes are being investigated to promote tissue regeneration. Initial applications show promising results in the treatment of cartilage defects and muscle injuries. Certain companies are offering exosome-based injections for regenerative orthopaedics and aesthetics.
Haarwachstumstherapien
Exosomes are increasingly being used in hair care products and scalp treatments with the intention of promoting hair growth and reducing hair loss. Clinical applications combine exosomes with PRP (platelet-rich plasma) to stimulate hair follicle regeneration.
Functional foods and dietary supplements
Plant exosomes from foods such as grapes and ginger are used in dietary supplements to provide antioxidant and anti-inflammatory benefits. Some companies are developing exosome-rich foods to support the microbiome and improve intestinal health .
For example, exosomes from ginger are used in functional drinks and dietary supplements as they can carry anti-inflammatory agents that are particularly beneficial for people with gastrointestinal complaints.
Drug development and drug delivery:
Pharmaceutical companies are researching exosomes as carriers for targeted drug delivery. Initial trials show that exosomes can precisely transport active ingredients to diseased tissues. Exosomes are being investigated as vehicles for targeted drug delivery, particularly in oncology.
Vorteile exosomaler Anwendungen
- Highly efficient cell communication: Exosomes transmit biological signals specifically to target cells.
- High bioavailability: Plant exosomes are stable against digestive enzymes and enter the organism intact.
- Regenerative potential: Exosomes are said to accelerate wound healing and tissue repair.
- Broad applications: Medicine, cosmetics and functional nutrition could benefit significantly from exosomes.
- Targeted drug delivery: Exosomes offer an opportunity for targeted therapies through the transport of bioactive molecules.
Challenges and open questions
Despite the promising potential of exosomes, there are still some hurdles that make widespread use difficult. There is a lack of long-term studies on safety and efficacy, which makes clinical approval difficult. In addition, the regulatory requirements are inconsistent, as exosomes could be classified as medicinal products, food supplements or cosmetic active ingredients depending on the area of application. Depending on whether patenting is possible, there are more or less incentives from the private sector to invest a lot of money in research.
Production is also challenging: isolation, purification and scaling require complex biotechnological processes that currently incur high costs. In addition, there are immunological risks, as exosomes can potentially trigger unexpected reactions in the immune system.
There are additional ethical concerns with the use of human exosomes, particularly when they are derived from stem cells. Standardization of manufacturing processes and further research are necessary to establish exosomes as a safe and effective therapeutic tool.
Zukunftsperspektiven der Exosomen-Forschung
Exosomes are more than just cell fragments - they represent a highly developed platform for cellular signal transduction and intercellular mass transport. While plant exosomes are already being explored in functional nutrition, human exosomal applications face regulatory and technological challenges. Ongoing research will help to further develop exosomes as an innovative therapeutic option for regenerative medicine, targeted drug delivery and personalized medicine.
