When the somatic cell cloned embryonic stem cells showed an immune rejection response, the method that emerged is the fertilized egg embryonic stem cell. It is this method that Dr. Hwang Woo-seok, who was once called a ‘national scientist’, tried.
The method is simple. After extracting only the nucleus from the patient’s somatic cells, it is replaced with the nucleus of a fertilized egg.
Since all human genetic information is in the nucleus, using this method, stem cells that are genetically identical to the patient’s somatic cells can be created. In theory, patient-specific transplantation is possible and there is no rejection, so it has once emerged as an optimal method.
However, when I wanted to solve a biological problem, an ethical problem arose.
Embryonic stem cells necessarily require a human fertilized egg, and the possibility of developing into a fetus must be ruled out for use in therapy. The problem is that because of this, research or treatment using embryonic stem cells can be a potential ‘murder’.
somatic cell cloning embryonic stem cells
*No transplant rejection
*Theoretically, patient-specific transplantation is possible
*The method Dr. Hwang Woo-seok tried
*No success stories yet
- Ethical problems arise due to the need for large amounts of eggs
- Human cloning possible
fertilized egg embryonic stem cell
*Differentiation into various cells
- Accumulation of various research achievements
- Immune rejection can be resolved to some extent by making a stem cell bank
- Bioethics problems exist due to the use of fertilized eggs
- Current clinical application is not possible due to cancer
Induced pluripotent stem cells
- No ethical issues because fertilized eggs are not used
*Differentiation into various cells
*Difficulty in clinical application because cancer may occur
- Early aging appears in the process of differentiation, limiting the ability to differentiate and reproduce
adult stem cells
*After fertilized egg stem cells, research is active
- Accumulation of various research achievements
*No immune rejection
- Safety has been proven and clinically applied
- The differentiation performance is lower than that of embryonic stem cells, but pluripotency has been recently demonstrated
*Limited stem cell capacity depending on the collection site
Controversially, scientists and doctors agree that a person can be considered a single human, usually 14 days after fertilization. In particular, there are many views that it cannot be regarded as an independent organism if it is frozen after artificial insemination for research purposes. The Constitutional Court also supported this view and did not recognize the fundamental right of frozen embryos for research purposes. The Constitutional Court held that the person who created the embryo has the right to decide on the embryo, leaving the possibility that artificial insemination embryos can be used for research purposes.
However, this is only a decision of the Constitutional Court. As the Constitutional Court is a national body and legal standards are flexible according to the times and social conditions, it may be a decision considering the growing importance of stem cell research.
Moreover, some argue that the embryo should be regarded as life from the time of fertilization, and therefore the embryo also has the right to life. Even in the United States, where conservative Protestantism is strong, some states, such as Louisiana and Virginia, legally recognize the right of an embryo and stipulate that a proxy can be employed. Even in the religious circles, it is against bioethics to treat embryos that have been fertilized according to the will of others, not embryos.
On the one hand, there is also the problem that somatic cell cloned embryonic stem cells have the potential to create another genetically identical individual, i.e., a clone. Even if scientific issues are somehow settled, ethical issues are not easily decided. The reason why scientists in the past took a cautious approach to stem cell research was because the ethical burden was so great. Is there no workaround?
turn the cell clock backwards
The solution came from an unexpected place that didn’t seem to have anything to do with stem cells. If embryonic stem cells are the problem, shouldn’t the embryo be used? If the ability of somatic stem cells is insufficient, shouldn’t it be possible to create sufficient capacity? First of all, were somatic cells and somatic stem cells not once embryonic stem cells? This is how the research on ‘redifferentiation’ began to attract attention.
Professor John Gurdon, a pioneer in somatic cell dedifferentiation research ⓒWelcome Foundation
A fertilized egg undergoes cell division to transform into various somatic cells. This process is called differentiation, and reverse differentiation is turning it upside down to create a fertilized egg from a somatic cell.
Research on dedifferentiation existed before the concept of stem cells appeared. Scientists wondered why the obvious difference between a fertilized egg and a somatic cell occurred, and thought the secret was in the egg. This is because it was already widely known that sperm only transmit genetic material. Then, since most of the nucleus of a cell is occupied by genetic material, even if the nucleus of an egg is removed and the nucleus of a somatic cell is transplanted there, it will be able to develop as an intact individual.
Professor John Gurdon (University of Cambridge, UK), who shared the Nobel Prize in Physiology or Medicine, succeeded in cloning a frog using this principle in 1962.
With this experiment, Professor Gurdon proved that an intact individual can be born even with the genetic information of somatic cells that have been differentiated, and found that a certain substance in the cytoplasm of an egg plays an important role in individual development. Through the cloned sheep Dolly, which was born in 1996, Professor Gerdon’s discovery was reconfirmed in mammals, and repeated experiments on cloned animals led to a full-scale research on stem cells.
If so, what material in the egg has the power to generate an individual? If this substance is injected, will somatic cells that have completed differentiation develop into intact individuals? Prof. Shinya Yamanaka (Kyoto University, Japan) who was awarded the Nobel Prize in Physiology or Medicine along with Professor Iga Iga who provided the answer to this question.
Professor Shinya, who overcame numerous failures and pioneered an original academic world ⓒNobel Foundation
Professor Shinya noted that there are transcription factors that are characteristic of embryonic stem cells. A transcription factor is a substance that regulates the expression of a specific gene. In 2006, Professor Shinya injected four transcription factors (Oct4, Sox2, Klf4, c-Myc) of embryonic stem cells into somatic cells that have been differentiated and succeeded in creating cells with similar capabilities to embryonic stem cells, i.e. iPS. .
iPS derived from somatic cells can differentiate into any cell like embryonic stem cells and can divide indefinitely. Since it can be made using the patient’s own somatic cells without using fertilized eggs, there is no worry about immune rejection and ethical issues can be avoided. Stem cell research, which has faced difficulties due to various problems, is truly ‘Deus ex Machina’.
Could it be the next blue chip in the medical industry?
By using stem cells, it is possible to treat diseases that were previously impossible or very difficult to treat. In addition, theoretically, there are few side effects, the effect is excellent, and the procedure is not difficult. It is highly likely to become the goose that lays golden eggs in the medical industry.
Therefore, advanced countries such as the US, EU, and Japan have actively supported stem cell research. In the United States, regulations on embryonic stem cell research were largely lifted under the Obama administration, and in 2009, the Food and Drug Administration (FDA) officially approved embryonic stem cell clinical trials.
The UK also allows research on human embryos with minimal ethical rules, and China also jumped in late, giving support, such as acknowledging almost all research on cloning embryos for therapeutic purposes. Japan has shifted its direction to iPS research and currently holds the largest number of iPS-related patents and research achievements in the world.
Of course, Korea was not alone. As it almost took the lead in stem cell research at one time, a Korean company commercialized the world’s first stem cell treatment. However, it is regrettable that research on adult stem cells, hematopoietic stem cells, and mesenchymal stem cells has been active due to the fact that regulations on embryonic stem cell research have become more severe since the Hwang Woo-suk shock. In a way, it was half the study. As a result, the technological competitiveness of stem cells has been hovering around the world’s 12th to 14th place for several years.
Stem cell research continued steadily in several fields.
Bio venture companies such as Medipost are developing stem cell treatment technologies and
It has improved the development of incurable diseases and commercialized related drugs. ⓒDong-A Ilbo
The government has recently recognized the importance of stem cells, and the Ministry of Education, Science and Technology, the Ministry of Knowledge Economy, and the Ministry of Health and Welfare are promoting related policies with the goal of entering the global TOP 5 in the field of stem cells. As iPS receives full-fledged attention, research on it is expected to be active.
Fortunately, the aftermath of Hwang Woo-suk’s shock has passed and stem cells have begun to appear in the media again. With the news of the Nobel Prize in Physiology or Medicine, public opinion is turning in favor of stem cells.
The treatment that Corporal Hernandez and Baek Guang received was obviously an unusual, experimental treatment. However, within 5 to 10 years, there will be a paved way for patients suffering from incurable diseases to be easily cured by stem cell treatment.