In this blog post, we will explore the possibilities and innovations that stem cell research could bring to disease treatment and regenerative medicine.
All organs and tissues in our bodies originate from a mass of stem cells created by the division of a fertilized egg. Stem cells are different from other somatic cells in that they can not only replicate themselves indefinitely, but also differentiate into various types of cells, such as skin, muscle, and blood cells. Research on the differentiation potential of stem cells has the potential to bring about revolutionary advances in the treatment of intractable diseases and regenerative medicine, and is being actively pursued around the world. There are two main types of stem cells that can be obtained from mammals: embryonic stem cells obtained from embryos and adult stem cells obtained from adult tissues. Embryonic stem cells are collected from embryos in the blastocyst stage, which is formed a few days after fertilization.
A fertilized egg starts as a single cell, divides into two, four, eight, and 16 cells, and after about four to five days, it reaches a stage called the blastocyst. The blastocyst consists of an outer layer and an inner cell mass. The outer layer develops into the placenta, and the inner cell mass grows into the actual embryo. Embryonic stem cells are obtained from this inner cell mass, and these cells have “pluripotency,” which means they can differentiate into any type of cell, or “totipotency,” which means they can develop into a whole organism.
Just as newborn babies have unlimited potential, embryonic stem cells have a wide range of medical applications, but they are the subject of serious ethical debate because embryos must be destroyed in the research process. Adult stem cells are obtained from progenitor cells and other undifferentiated cells that work to repair damaged tissue in the adult body.
When damage occurs, these cells move to the affected area and differentiate into the necessary cells. They are found in various tissues such as the brain, bone marrow, blood, blood vessels, skeletal muscles, skin, and liver, but they exist in very small quantities, making it difficult to obtain large amounts, and they are already partially differentiated, limiting the types of cells they can differentiate into. In addition, if the cells are not from the patient themselves, an immune rejection response may occur during transplantation.
Embryonic stem cells can be mass-produced and, under the right conditions, can differentiate into various tissues, so in theory, they can be transplanted into other individuals or even other species. However, if differentiation is not precisely controlled, there is a possibility that they will turn into cancer cells, so sophisticated research is essential to ensure safety. Adult stem cells are not subject to ethical controversy, but their limited availability and differentiation range are obstacles to their use.
The greatest value of stem cells lies in their ability to replace damaged tissues or organs in large quantities for the treatment of intractable diseases. For example, Parkinson’s disease is caused by the death of dopamine-producing nerve cells, and the most effective treatment currently known is fetal brain tissue transplantation, which is extremely limited in supply and raises ethical issues. If dopaminergic nerve cells can be produced stably and in large quantities from stem cells, it could bring about a revolutionary change in patient treatment. Mass production of insulin-secreting beta cells could also open new avenues for the treatment of type 1 diabetes. In fact, stem cell therapy is already being used in some areas, such as stroke and knee arthritis regeneration, and the market value of the regenerative medicine field is expected to grow to hundreds of trillions of won by 2025.
However, embryonic stem cell research still faces ethical issues as it requires the destruction of blastocysts. Some countries allow this, but Germany, Austria, and Italy prohibit it by law, and the United States and some European countries allow it only under limited conditions. On the other hand, adult stem cells have few ethical controversies, but their medical applications are limited.
The most innovative discovery in stem cell research over the past 20 years is induced pluripotent stem cells (iPS cells). These are cells that have been made to have the same versatility as embryonic stem cells by introducing specific genes into adult cells, and since they are derived from the patient’s own cells, there is almost no risk of immune rejection. iPS cell technology was established in 2007 by Dr. Shinya Yamanaka’s team in Japan and is currently being used in research on various intractable diseases such as Huntington’s disease, autoimmune diseases, and spinal cord injuries. Furthermore, in the 2020s, experiments are underway to combine this technology with gene editing technology (CRISPR) to correct disease-causing genes and differentiate them into healthy cells. This approach goes beyond simple treatment and opens up the possibility of a complete cure.
Stem cell research is still in its early stages, but given the success of bone marrow stem cell transplants in treating blood cancers such as leukemia, there is ample potential for its application to other diseases. However, safety, ethical, and cost issues must be resolved, and its effectiveness must be proven through large-scale clinical trials. The future of stem cells has the potential to bring innovation to human health as a whole, beyond disease treatment, including organ regeneration, personalized treatment, and delaying aging. As Nancy Reagan said, “Stem cell research is the hope that will give us answers we have not yet seen or heard,” this field will continue to be an important pillar of medical advancement for humanity.
