Stem cells are not yet fully understood, but they are emerging as a powerful therapeutic tool with many different types and potential applications. Embryonic stem cells, adult stem cells, and iPS stem cells all have different characteristics and ethical issues, and each has the potential to drive future medical breakthroughs.
Even the most science-literate layperson has heard the term “stem cell” at least once. In 2004, a South Korean scientist made a groundbreaking discovery about stem cells that sent the world into a frenzy. This was more than just an academic discovery, it was an indication of the potential of stem cell research. Although the discovery was later proven to be false, it certainly introduced the public to the word “stem cell”. Since then, interest in stem cells has continued to grow, and they are now more commonly known as “stem cell cures for terminal diseases,” “stem cell plastic surgery,” “stem cell cosmetics,” and so on.
While the term stem cells is no longer unfamiliar to the public, fewer people know much about them than you might think. In fact, according to a 2021 survey by the Ministry of Health and Welfare, only 36% of South Koreans said they knew exactly what stem cells are. This shows that stem cells are still not fully understood by the public. Despite these important scientific discoveries, the fact that so few people have a concrete understanding of what stem cells are suggests that we need to do more education and outreach about stem cells.
So, what is a “stem cell” if you’ve heard it before? Consider the process of development: first, a sperm and egg meet to form a fertilized egg, which divides into many cells through cell division, and then these cells differentiate into cells with specific functions in the body, creating a fetus. Before differentiation, the fertilized egg is a stem cell. Stem cells are called stem cells in English, or gan cells in Chinese, which means they are the cells that underlie all cells. Stem cells are primitive cells that have not yet decided what they will become, and depending on the environment and how they are manipulated, they can differentiate into various cells in the body, such as muscle cells, nerve cells, skin cells, liver cells, and more.
Stem cells can be broadly categorized into embryonic stem cells and adult stem cells. As the name implies, embryonic stem cells are stem cells derived from embryos obtained through in vitro fertilization, while adult stem cells are stem cells that exist in the body.
First, embryonic stem cells are highly pluripotent, meaning they can theoretically differentiate into any cell. By nuclear transfer (taking the nucleus out of one cell and transplanting it into another cell with the nucleus removed), an embryo can be given the same genes as the patient and then differentiated to avoid immune rejection. However, the use of embryos that are potentially human and could lead to human cloning raises major ethical issues. This ethical controversy is one of the main obstacles to the progress of embryonic stem cell research, and it is essential to reach a social consensus. Adult stem cells are undifferentiated cells (stem cells) in the body. Examples include hematopoietic stem cells from bone marrow or stem cells derived from adipose tissue. Because they are derived from the patient’s own body, they are free from ethical concerns compared to embryonic stem cells. However, they are very limited compared to embryonic stem cells. The types of cells that can be differentiated, the amount of cells, and the length of time they can be cultured are all limited, which narrows the scope of their use.
Stem cells can be used for therapeutic treatments. Most of the treatments using embryonic stem cells are still in the research phase, but the possibilities are endless. Recently, a clinical trial to treat blindness using embryonic stem cells was successful in South Korea. When embryonic stem cells were cultured into retinal pigment epithelial cells and transplanted into the eyes of patients, three out of four patients showed improvement in vision. This is an important example of the potential for embryonic stem cell therapy to become a viable treatment. With commercialization expected as early as 2018, it’s clear that stem cell therapy is one step closer to becoming a reality. Adult stem cells are much more developed and researched than embryonic stem cells. There are currently treatments available on the market, and there are many clinical trial successes and real-world applications. For example, NatureCell recently announced that it will begin treating Burger’s disease (a vascular disease that causes necrosis of the extremities due to blocked blood vessels) using autologous adipose stem cells (a type of adult stem cell) as early as December of this year. Another example is the recent development of the “Cartistem chondroplasty treatment,” a treatment for degenerative arthritis using adult stem cells. Katistem, a mesenchymal stem cell therapy derived from allogeneic umbilical cord blood, is capable of regenerating cartilage damaged by arthritis.
Finally, we would like to describe the most recent stem cells, “iPS stem cells” (induced pluripotent stem cells, reverse differentiation stem cells). These stem cells reverse differentiation of already differentiated somatic cells, returning them to their pre-differentiation state. In other words, they turn the cell’s time backwards. The resulting stem cells are highly differentiated and non-rejecting, and there are fewer ethical issues because they come from adults. The emergence of iPS stem cells has opened up new horizons in stem cell research. It has the potential to become a leader in the field of regenerative medicine. Although there is still a lot of research to be done and much remains to be discovered, it is clear that these stem cells will revolutionize the field of medicine in the future. Currently, the most active research is being conducted in Japan, and Korea is following suit.
Stem cell research is no longer just a scientific curiosity, but an important field that directly affects our health and quality of life. Although there are still many ethical and technical issues to be resolved, the potential impact of stem cells on the medical world is unimaginable.
