In this blog post, we’ll look at the limits of adult stem cells and reprogrammed stem cells, and see why embryonic stem cell research is still important.
Somatic cell embryonic stem cell research in South Korea was taboo for a while after Dr. Hwang Woo-suk was prosecuted for ethical issues. The news emphasized only the unethical nature of embryonic stem cell research, and embryonic stem cells were considered research that violated human dignity. As time passed, research in Korea focused mainly on iPS and adult stem cells, and embryonic stem cell research was gradually forgotten. However, on May 17, 2016, about 10 years later, the National Bioethics Committee conditionally approved Cha Hospital’s somatic cell cloning research plan, and embryonic stem cell research once again became the center of heated debate. Embryonic stem cells can greatly contribute to the medical field, such as in the treatment of intractable diseases and organ regeneration, so research is essential. However, many people oppose it due to its potential misuse in human cloning and unethical experimentation. In this article, we will examine the reasons why embryonic stem cell research should be allowed and analyze the logical flaws in the arguments of those who oppose it.
Stem cells could provide new organs for patients suffering from organ damage. Currently, organs are transplanted from other people or artificial organs are created and transplanted to people who have lost organs due to cancer or other incurable diseases. However, there are serious problems with this method. First, when an organ is transplanted from another person, the immune system recognizes the transplanted organ as a foreign substance, which can cause an immune rejection reaction, leading to acute shock and death. Immunosuppressants are used to prevent this, but they weaken the body’s immune system, making it susceptible to disease. Another problem is that there are far fewer organ donors than there are organ transplant candidates. Artificial organs have been developed as a substitute, but they can also cause immune rejection and require surgery to periodically replace the power source, which is inconvenient. Furthermore, if the machine malfunctions, it can be life-threatening, especially if an important organ such as the heart has been replaced with an artificial heart. However, these problems can be solved by differentiating and culturing stem cells. Since the cells are cultured from the patient’s own body, there is no immune rejection, and there is no risk of malfunction because the organ is not replaced with a machine.
Furthermore, stem cells will help discover treatments for intractable diseases for which there are currently no adequate treatments. For example, Parkinson’s disease is a disease caused by the loss of nerve cells that secrete dopamine in the brain, with clinical symptoms usually appearing in the 60s, and the cause of the disease is not yet clear. Symptoms include autonomic nervous system disorders such as tremors, rigidity, slow movement, and postural instability, as well as depression. Levodopa therapy, which involves administering levodopa, a precursor to dopamine, is the most common treatment, but there is currently no cure. Current treatment mainly focuses on alleviating symptoms to help patients maintain their daily lives as much as possible. However, recent research by biologists suggests that stem cells may offer a complete cure for Parkinson’s disease. According to a recent study published in Nature in 2017, the symptoms of Parkinson’s disease were improved using induced pluripotent stem cells (iPS cells). The research team reprogrammed iPS cells into dopamine-producing cells, transplanted them into the brains of monkeys with Parkinson’s disease, and observed them for two years. The results showed that the dopamine-producing cells survived for more than two years and no tumors formed. Currently, research using stem cells is limited to alleviating the symptoms of Parkinson’s disease, but with further technological advances, it is expected that destroyed neurons will be completely replaced. Juvenile diabetes, which occurs when the immune system attacks its own beta cells and prevents them from producing insulin, is also expected to be completely cured using stem cells.
Despite these advantages, those who oppose embryonic stem cell research cite ethical grounds. They argue that embryonic stem cells could be misused for human cloning and that unethical practices such as the unauthorized extraction of embryos could occur during the research process. However, this can be prevented through legal regulations. The Act on Bioethics and Safety states “Embryo creation medical institutions may provide remaining embryos for research purposes only if the consenting party agrees to their use for research purposes after the preservation period has expired.” It also stipulates that “when providing remaining embryos and remaining reproductive cells, the institutional committee of the embryo creation medical institution shall receive and review the usage plan and research plan submitted by the embryo research institution, somatic cell cloning embryo research institution, or other research institution.” In 2005, Dr. Hwang Woo-suk’s cloned embryo research became a major controversy not only because of the manipulation of research papers, but also because of the coercive extraction of eggs from female researchers belonging to the research team. Currently, opponents of embryonic stem cells argue that there is no guarantee that such a situation will not happen again. However, this is not a problem with embryonic stem cells themselves, but rather a result of inadequate legal regulations. The Bioethics Act clearly states that only surplus embryos that have been approved in advance can be used, and that embryos cannot be created for purposes other than pregnancy. If the government and the state regulate and manage the use of embryonic stem cells in accordance with the law, unethical situations will not arise in experiments.
The advantages mentioned above can be replaced by induced pluripotent stem cells or adult stem cells, but one may wonder why embryonic stem cells, which are the subject of much ethical debate, must be used. However, embryonic stem cells cannot be replaced by other stem cells at this time. Adult stem cells and induced pluripotent stem cells have limited differentiation capabilities and research limitations, making it difficult to conduct advanced research. Adult stem cells already have a predetermined differentiation pattern, limiting researchers’ ability to differentiate them as desired, and there is a risk of immune rejection when using cells from other individuals. Furthermore, there is a limit to the amount that can be proliferated. For example, in order to use adult stem cells for Parkinson’s disease, a large number of aborted fetal cells are required for cell transplantation. However, embryonic stem cells can be used for research by first proliferating the cells and then differentiating them into dopamine cells necessary for treatment, making it easier to secure a larger quantity.
Although reprogrammed stem cells do not have the problems associated with adult stem cells, they have a low success rate and safety issues. According to a research team led by Lawrence Goldstein at California State University, reprogrammed stem cells have a significant number of mutant genes, some of which are associated with cancer. The research team sequenced the genomes of 22 induced pluripotent stem cells and found an average of six mutant genes in each. These mutant genes were related to cell growth, and some were associated with cancer. This is about 10 times higher than the typical mutation frequency in cells. The virus used to introduce genes into cells to create reprogrammed stem cells can also irregularly insert itself into the cell’s genes, causing mutations and activating cancer genes, raising safety concerns. Embryonic stem cells are relatively free from these problems, allowing for safer research.
So far, we have examined the usefulness of embryonic stem cells, the necessity of research, and the logical flaws in the opposing arguments. Embryonic stem cells can provide solutions to difficult-to-treat degenerative diseases such as type 1 diabetes and Parkinson’s disease, as well as problems with organ transplants, but they must be researched because they cannot be replaced by induced pluripotent stem cells or adult stem cells. Furthermore, the claim that embryonic stem cell research is unethical can be resolved through legal regulations. We hope that embryonic stem cell research will solve problems in the medical field that currently have no solution.
