What are mesenchymal stem cell-derived exosomes
P rior to 1980, scientists had only discovered that cells continually secreted small bubbles that were thought to be waste products excreted by the cells. However, it was only in recent years that these bubbles began to receive attention when they were rediscovered to have the ability to aid in tissue repair.
Exosome is a small nano-sized bubble (30-150nm) secreted by cells. The bubbles contain nucleic acids, lipids, growth factors, proteins and other substances. These bubbles will be delivered and when absorbed by the surrounding cells, the cells will start to perform different functions as if they have received an order.
Exosomes are the bubbles that transport the goods.
In fact, cells are like logistics centers, and exosomes are the carriers of goods to be transported, controlling the delivery of goods to the right place at the right time, including to the cell next door or far away.
Research on exosomes
In the process of culturing stem cells, scientists have discovered that stem cells continuously excrete exosomes, which can interact with other cells around them to promote cellular repair. In recent years, a number of studies have demonstrated that stem cell exosomes have the following functions and have positive effects on different health problems.
1. Tissue repair: Promote tissue growth and wound healing, can also repair burns, e.g., liver injury, kidney injury, etc.
2. Joint repair: Promote cartilage tissue regeneration, e.g., degenerative arthritis.
3. Immune regulation: Reduce excessive inflammation, accelerate the removal of abnormal cells in the body, e.g., autoimmune diseases.
4. Neurodegeneration: Promotes the proliferation of nerve cells, e.g., Alzheimer's disease, Parkinson's disease, etc.
5. Medical aesthetic treatment: Stimulate the synthesis of collagen and elastin, stimulate hair follicles to produce hair, e.g., anti-aging, scar removal, hair breeding, and so on.
6. Antioxidant: Reduce free radical production to increase cell survival, e.g., heart disease.
Stem Cell Exosomes Promote Brain Neural Rejuvenation
After seven years of research, the research team of Associate Investigator Hua-Jung Li at the Institute of Cellular and System Medicine, National Health Research Institutes (NHRI), has discovered that stimulation of mesenchymal stem cells by a special technique can isolate "Stem Cell-derived Exosomes" (Stem Cell-Derived Exosomes), which have the function of repairing the cells and from which the active substances that can promote the regeneration of the brain nerves and restoration of the brain functions are identified, which is a new breakthrough in the regenerative medicine. This series of studies has been published in 《STEM CELLS Translational Medicine》, an authoritative international journal of regenerative medicine, in 2019 and 2020 respectively, and has been featured in foreign media.
In 2021, an article published in 《STEM CELLS Translational Medicine》 noted that exosomal components secreted by human amniotic fluid stem cells also have the ability to protect nerve cells. The analysis revealed that these exosomes are involved in the activation of the anti-apoptotic mechanism of message regulation, which in turn enables neurons to alleviate cognitive loss and slow down the apoptosis of neurons.
Exosomes regulate immune functions
Mesenchymal stem cells have immunomodulatory properties and can treat inflammatory diseases. Studies have shown that exosomes secreted by mesenchymal stem cells have the same immunomodulatory properties as cells, for example, exosomes from bone marrow mesenchymal stem cells can improve the degree of inflammation in rheumatoid arthritis, and there are a number of clinical trials that continue to prove their efficacy. Literature further points out that NK cells, dendritic cells, T cells, etc., will take up exosomes from mesenchymal stem cells to regulate their behavior, and it is now recognized that miRNAs can help cells regulate immune responses.
Exosomes are anti-aging
Because exosomes contain many growth factors, which have a certain effect on repairing tissues, and are therefore considered to have the function of helping to remove old and wasted cells and promoting cell regeneration. In recent years exosomes have an important position in the field of cosmetic dermatology, which is closely related to wound healing, promoting collagen proliferation, slowing down the aging of the skin, and reducing the formation of scars.
At present, there are many skin care products developed using exosomes around the world, the functions of which include reducing pigmentation, reducing fine lines, improving skin elasticity, etc., so as to improve skin texture and even out skin color, and to achieve the possibility of regeneration and repair against the age of the skin. That is to say, the current application of exosomes is not only to help wound repair, containing exosomes in cosmetics has become a new trend in anti-aging.
Exosomes promote hair regrowth
In the cells of the scalp and hair follicles, exosomes are recognized as potential factors in promoting hair growth. Exosomes regulate the hair growth cycle, stimulate the proliferation and differentiation of outer root sheath cells, promote the growth and migration of papillary cells in hair follicles, and inhibit apoptosis. For example, the Japanese team published the effect of exosomes in the treatment of alopecia, after 6 to 8 scalp injections, the volume of hair significantly more, the hairline range has also changed, the effect can be maintained at least one and a half years.
Advantages of Exosomes
1. Easily absorbed: Nano-sized and penetrates the blood-brain barrier.
2. Non-rejection: Highly compatible with cells, no rejection.
3. High stability: Easy to store, stable quality during transportation.
What's next for exosomes?
Professor Chang Chih-Hung, former President of the Taiwan Formosa Association Regenerative Medicine, said, ”Experts and scholars are beginning to think about whether exosomes can be refined in the future to find out the therapeutic effects of exosomes on those diseases, and after understanding the indications, perhaps they can be made into standardized medicines, which can be widely used in medical treatment, and also improve the bottleneck of the inability of the standardization of stem cell therapies.”