This blog post examines the potential and ethical controversies surrounding embryonic stem cell therapy, focusing on whether it could be the solution for treating incurable diseases.
Concept and Current Research Status of Embryonic Stem Cells
Interest in embryonic stem cell research, which had slowed down, is growing again following the recent announcement of research results showing that embryonic stem cells were used to restore vision in blind patients. According to the medical journal ‘The Lancet’, researchers successfully restored vision in 18 patients suffering from ‘dry age-related macular degeneration’ (a retinal disease causing blindness in the elderly) and ‘Stargardt’s macular dystrophy’ (a rare retinal disorder) by transplanting retinal pigment epithelial cells derived from embryonic stem cells. Among the patients participating in this clinical trial, 13 experienced improved vision. This is being evaluated as a case demonstrating the significant potential of embryonic stem cells for treating rare or intractable diseases.
Embryonic stem cells are a type of stem cell possessing the ability to differentiate into all tissues. Specifically, embryonic stem cells originate from the fertilized egg formed when a man’s sperm and a woman’s egg are fertilized. Embryonic stem cells, which can be extracted from blastocyst-stage embryos just before implantation or from fetuses miscarried between 8 and 12 weeks of pregnancy, theoretically have the potential to differentiate into all cell types that make up the human body. So, do these embryonic stem cells only have positive aspects?
Arguments of Pro-Embryonic Stem Cell Advocates
Pro-embryonic stem cell advocates support research and utilization for several reasons. First, they argue that embryos within 14 days of fertilization are merely a mass of cells, not human beings. However, this claim may be a deliberate attempt to avoid ethical issues by treating embryos as ‘cell masses’. The process by which a fertilized egg develops into an embryo, fetus, and newborn involves only morphological changes, not essential changes. When dignity is seen as inherent in life itself rather than increasing as form becomes more distinct, the proponents’ argument is not valid.
Second, proponents argue that embryonic stem cells can help treat incurable diseases. Saving a dying life is profoundly valuable, but this is only justified when it does not involve sacrificing another life or employing ethically problematic methods. Since an embryo can also be considered a life, treating incurable diseases by sacrificing another life cannot be justified. If incurable diseases can be treated through other ethically unproblematic methods, it is appropriate to further develop those approaches.
Third, proponents argue that embryonic stem cell research contributes to economic development. However, permitting embryo research for economic reasons equates human dignity with a value lower than material gain, posing a risk of creating an unethical society. If materialistic thinking becomes widespread, the wealth gained could instead corrupt society. Therefore, this argument cannot serve as sufficient justification for supporting embryonic stem cell research.
Arguments Against Embryonic Stem Cells
Opposition to embryonic stem cells can be summarized into four main points.
First, there are ethical concerns. Proponents often dismiss embryos as mere cell masses to avoid ethical issues. While embryonic stem cells are defined as cells that have lost their ability to form an entire organism (totipotency) after the removal of the outer layer, retaining only the ability to differentiate into various organs (pluripotency), research also shows that under appropriate culture conditions, they can reform the outer layer. This means it is impossible to deny that the embryo is essentially human life. Therefore, embryonic stem cell research cannot be free from the ethical issue of exploiting life.
Second, embryonic stem cells are not the only method for treating incurable diseases. Beyond embryonic stem cells, stem cells also include adult stem cells and induced pluripotent stem cells. Adult stem cells can be extracted from sources like maternal umbilical cord blood or adult bone marrow, offering advantages such as no immune rejection and a low risk of teratoma formation. Furthermore, induced pluripotent stem cells are cells reprogrammed to an early stage with characteristics similar to embryonic stem cells by introducing specific genes and proteins into somatic cells. They also lack immune rejection issues and make it easier to find somatic cell donors. The existence of these alternatives without ethical concerns further diminishes the justification for using embryonic stem cells.
Third, there is the issue of therapeutic safety with embryonic stem cells. In 2014, Japan approved a clinical trial using embryonic stem cells, but it was subsequently halted due to concerns about side effects and the confirmation of successful treatments using induced pluripotent stem cells. Clinical trials using embryonic stem cells carry risks of rejection reactions or teratoma formation, making it difficult to ensure safety in actual treatments. In contrast, treatments using induced pluripotent stem cells have shown almost no side effects.
Fourth, there are side effects and risks associated with the egg retrieval process. Embryonic stem cells are harvested from embryos obtained through in vitro fertilization (IVF). During this process, women may experience side effects such as ovarian hyperstimulation syndrome (OHSS) due to the administration of ovulation-inducing drugs, which can cause the ovaries to enlarge abnormally. Long-term use of ovulation induction drugs may increase the risk of ovarian hyperstimulation syndrome and ovarian cancer. Additionally, the egg retrieval process, performed under general anesthesia, carries risks such as respiratory distress or cardiac arrest. Using such dangerous methods to obtain embryonic stem cells is inappropriate.
Conclusion
We have examined the concept of embryonic stem cells and the positions of proponents and opponents. Embryonic stem cells involve ethical issues, are not the only method for treating incurable diseases, and present numerous problems regarding treatment safety. Furthermore, the side effects and risks women endure during the egg retrieval process are significant. Therefore, research and experiments using embryonic stem cells should be halted.
