Stem cells are undifferentiated cells that can differentiate into various body tissues and are divided into embryonic stem cells, adult stem cells, and induced pluripotent stem cells. These stem cells offer revolutionary possibilities for the treatment of several diseases, including leukemia, Parkinson’s disease, and diabetes, and induced pluripotent stem cells in particular are considered a major breakthrough in addressing ethical concerns. In the 2020s, the convergence with gene editing technology is making treatments more sophisticated and safer.
The 21st century is the age of biotechnology, and it’s no exaggeration to say that stem cells are one of the biggest drivers of this era. Like the industrial revolution in the past, fully understanding stem cells is a medical treatment revolution that could surpass any past industrial revolution. Stem cell research is a global endeavor, and the results are already impacting our lives.
There are three main types of stem cells: embryonic stem cells, which are formed when a fertilized egg first divides; adult stem cells, which are contained in mature tissues; and induced pluripotent stem cells, which can revert adult cells back to their pre-differentiation state.
Stem cells were first recognized in 1961 by Till and McCloach. They discovered adult stem cells while conducting research on cancer treatments in mice. When the mice were irradiated, they developed a bone marrow deficiency, which was restored when they were transplanted with normal bone marrow cells. This experiment showed that bone marrow cells contain hematopoietic stem cells, which are the cells that make new blood cells. Adult stem cells are undifferentiated cells found within the “differentiated” cells of a tissue or organ. Because they are undifferentiated, when transplanted into a tissue, adult stem cells can differentiate stably into that tissue without the potential to become cancerous. They are also capable of self-transplanting their own cells, which has the advantage of not causing immune rejection. However, the disadvantages are that the ability to differentiate into various tissues is very limited, so it is difficult to apply to all parts of the body, and because there are very few cells in each tissue, it is difficult to obtain a large amount, and because of immune rejection, it is difficult to donate and donate.
In 1988, Dr. James Thompson’s team in the United States established the concept of human embryonic stem cells. The idea was that embryonic stem cells, which can be obtained from a fertilized egg created by the fertilization of a sperm and an egg, could be used to treat various human diseases because they can differentiate into any cell, just as a single embryonic cell can differentiate into any cell to create a complete human individual. The process of extracting embryonic stem cells is as follows Remove the nucleus from a normal human body cell. The nucleus of the somatic cell is injected into a de-nucleated egg and fused, resulting in an embryonic cell. These embryonic cells are cultured to form blastocysts. When a blastocyst becomes a blastocyst, it is divided into an inner cell mass and an outer cell mass, and the inner cell mass has pluripotency to differentiate into all kinds of body cells. Therefore, stem cells are extracted from the inner cell mass of the blastocyst and differentiated into various cells. Embryonic stem cells are technically easier to obtain than adult stem cells and have the advantage of being able to remain undifferentiated in vitro for a longer period of time. If embryonic stem cells can be used to create an unlimited number of organ cells for the treatment of various incurable diseases and transplanted in a test tube, the dream of longevity will be realized. This technology is essential as donated organs are in short supply. Currently, attempts are being made to treat patients with leukemia, Parkinson’s disease, diabetes, and other diseases by culturing and injecting normal cells from outside the body to replace the failed cells.
In addition, it offers new hope for infertile couples: while there are many options for couples who have problems with sperm and are unable to fertilize using normal methods, somatic cell nuclear transfer, as mentioned above, allows fertilization without sperm, opening the way to solve this problem on a completely different level. By using the mother’s egg for the cytoplasm and the mother’s or father’s somatic cells for the nucleus, it is possible to have a daughter who looks exactly like the mother, or a son who looks exactly like the father. In addition, with embryo isolation techniques, fertilized eggs can be examined before implantation in the uterus to filter out defects or correct only those genes to achieve the desired healthy baby.
However, embryonic stem cells also have a number of obvious drawbacks. They are very difficult to differentiate, so they have the potential to develop into cancerous cells, which requires technical precision. There is also a lot of debate about the use of embryonic stem cells from a bioethical point of view, due to the fact that the supply of eggs is not always smooth due to legal and ethical issues, and the fact that potentially life-giving embryos must be destroyed to save a patient’s life. An embryo is a stage before it becomes a fetus, and depending on your point of view, it may not be considered life. However, given that embryonic stem cells grow to become human beings, there are various arguments from different religions and beliefs that the same bioethics that apply to humans should apply to embryos, which is why research is not being actively conducted. In addition, most countries have bioethics laws, and in Korea, the ‘Bioethics and Safety Act’ has been enacted. This law prohibits the use of embryos to create embryonic stem cells. Therefore, in order to conduct embryonic stem cell research in Korea, only sperm and unfertilized eggs or frozen embryos that are scheduled to be discarded after infertility treatment can be used, so there are practical difficulties in conducting explosive research.
These bioethical issues have led to the emergence of a new type of stem cell. They are induced pluripotent stem cells. In other words, they are also called reverse differentiation stem cells. Induced pluripotent stem cells are cells that have already differentiated and reverted to a cellular stage before differentiation. By introducing and expressing four specific genes that cause reverse differentiation into the patient’s skin cells, or by extracting and injecting the reverse differentiation-inducing proteins made by the four genes back into the skin cells, the skin cells become stem cells that can differentiate into various parts, such as embryonic stem cells. These are called reverse differentiation stem cells. In 2006, Professor Shinya Yamanaka and his team succeeded in creating stem cells with the ability to differentiate like embryonic stem cells by introducing genes into rat skin cells. The discovery of induced pluripotent stem cells was so significant that he was awarded the Nobel Prize in Physiology or Medicine in 2012 for his work. This is a feat so great that the textbooks of human biotechnology should be rewritten, and it is clear that the ability to regenerate limbs, vertebrae, etc. in lizards is a great achievement of 21st century biotechnology. It is also a tremendous source of hope for burn victims, people who have lost limbs or other parts of their bodies, and people with spinal paralysis. Although embryonic stem cells have had their own bioethical issues, such as the direct use of a woman’s eggs, and the risk of immune rejection when transplanted into a patient, induced pluripotent stem cells are significant because they solve these ethical and technical problems in one fell swoop.
In December 2009, the BBC broadcast a story about eight people who received stem cell therapy and regained their sight. Mr. Turnbull, whose cornea was damaged in one eye by a chemical accident, is a prime example of a direct application of induced pluripotent stem cells. Dr. Francisco Figueiredo and his team at the North East of England Stem Cell Institute (NESCI) in the UK extracted and cultured stem cells from Mr. Turnbull’s normal eye. The stem cells were transplanted into the blind eye, and Mr. Turnbull was able to see again in one eye.
However, because the research is still ongoing, there may be side effects that we don’t yet know about. For example, there are concerns that they may cause mutations or other genetic abnormalities, and there is also the possibility of tumors arising from the genetic modification process of reverse differentiation of somatic cells into stem cells. Therefore, much further research is needed before they can be used safely in patients.
To summarize, stem cells are undifferentiated cells that have the ability to differentiate into different tissues. Since their discovery, there has been a lot of research and development. The history of stem cell research has been focused on solving problems that arise when applying stem cells to the human body. To overcome the biggest problem with adult stem cells, their limited ability to differentiate into different tissues, embryonic stem cells were discovered. To overcome the ethical issues of embryonic stem cells, a new breakthrough, induced pluripotent stem cells, was discovered. Humanity has always pioneered new ways to solve problems, and I believe that the current problems will be solved one day. In the 2020s, researchers are actively combining gene editing technology with stem cell therapy to develop more sophisticated and safer stem cell therapies. Therefore, if it becomes possible to control the differentiation of induced pluripotent stem cells, which is currently impossible, the liberation from disease that mankind has dreamed of will not be too far away.
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The 21st century is the age of biotechnology, and it’s no exaggeration to say that stem cells are one of the biggest drivers of this era. Like the industrial revolution in the past, fully understanding stem cells is a medical treatment revolution that could surpass any past industrial revolution. Stem cell research is a global endeavor, and the results are already impacting our lives.
There are three main types of stem cells: embryonic stem cells, which are formed when a fertilized egg first divides; adult stem cells, which are contained in mature tissues; and induced pluripotent stem cells, which can revert adult cells back to their pre-differentiation state.
Stem cells were first recognized in 1961 by Till and McCloach. They discovered adult stem cells while conducting research on cancer treatments in mice. When the mice were irradiated, they developed a bone marrow deficiency, which was restored when they were transplanted with normal bone marrow cells. This experiment showed that bone marrow cells contain hematopoietic stem cells, which are the cells that make new blood cells. Adult stem cells are undifferentiated cells found within the “differentiated” cells of a tissue or organ. Because they are undifferentiated, when transplanted into a tissue, adult stem cells can differentiate stably into that tissue without the potential to become cancerous. They are also capable of self-transplanting their own cells, which has the advantage of not causing immune rejection. However, the disadvantages are that the ability to differentiate into various tissues is very limited, so it is difficult to apply to all parts of the body, and because there are very few cells in each tissue, it is difficult to obtain a large amount, and because of immune rejection, it is difficult to donate and donate.
In 1988, Dr. James Thompson’s team in the United States established the concept of human embryonic stem cells. The idea was that embryonic stem cells, which can be obtained from a fertilized egg created by the fertilization of a sperm and an egg, could be used to treat various human diseases because they can differentiate into any cell, just as a single embryonic cell can differentiate into any cell to create a complete human individual. The process of extracting embryonic stem cells is as follows Remove the nucleus from a normal human body cell. The nucleus of the somatic cell is injected into a de-nucleated egg and fused, resulting in an embryonic cell. These embryonic cells are cultured to form blastocysts. When a blastocyst becomes a blastocyst, it is divided into an inner cell mass and an outer cell mass, and the inner cell mass has pluripotency to differentiate into all kinds of body cells. Therefore, stem cells are extracted from the inner cell mass of the blastocyst and differentiated into various cells. Embryonic stem cells are technically easier to obtain than adult stem cells and have the advantage of being able to remain undifferentiated in vitro for a longer period of time. If embryonic stem cells can be used to create an unlimited number of organ cells for the treatment of various incurable diseases and transplanted in a test tube, the dream of longevity will be realized. This technology is essential as donated organs are in short supply. Currently, attempts are being made to treat patients with leukemia, Parkinson’s disease, diabetes, and other diseases by culturing and injecting normal cells from outside the body to replace the failed cells.
In addition, it offers new hope for infertile couples: while there are many options for couples who have problems with sperm and are unable to fertilize using normal methods, somatic cell nuclear transfer, as mentioned above, allows fertilization without sperm, opening the way to solve this problem on a completely different level. By using the mother’s egg for the cytoplasm and the mother’s or father’s somatic cells for the nucleus, it is possible to have a daughter who looks exactly like the mother, or a son who looks exactly like the father. In addition, with embryo isolation techniques, fertilized eggs can be examined before implantation in the uterus to filter out defects or correct only those genes to achieve the desired healthy baby.
However, embryonic stem cells also have a number of obvious drawbacks. They are very difficult to differentiate, so they have the potential to develop into cancerous cells, which requires technical precision. There is also a lot of debate about the use of embryonic stem cells from a bioethical point of view, due to the fact that the supply of eggs is not always smooth due to legal and ethical issues, and the fact that potentially life-giving embryos must be destroyed to save a patient’s life. An embryo is a stage before it becomes a fetus, and depending on your point of view, it may not be considered life. However, given that embryonic stem cells grow to become human beings, there are various arguments from different religions and beliefs that the same bioethics that apply to humans should apply to embryos, which is why research is not being actively conducted. In addition, most countries have bioethics laws, and in Korea, the ‘Bioethics and Safety Act’ has been enacted. This law prohibits the use of embryos to create embryonic stem cells. Therefore, in order to conduct embryonic stem cell research in Korea, only sperm and unfertilized eggs or frozen embryos that are scheduled to be discarded after infertility treatment can be used, so there are practical difficulties in conducting explosive research.
These bioethical issues have led to the emergence of a new type of stem cell. They are induced pluripotent stem cells. In other words, they are also called reverse differentiation stem cells. Induced pluripotent stem cells are cells that have already differentiated and reverted to a cellular stage before differentiation. By introducing and expressing four specific genes that cause reverse differentiation into the patient’s skin cells, or by extracting and injecting the reverse differentiation-inducing proteins made by the four genes back into the skin cells, the skin cells become stem cells that can differentiate into various parts, such as embryonic stem cells. These are called reverse differentiation stem cells. In 2006, Professor Shinya Yamanaka and his team succeeded in creating stem cells with the ability to differentiate like embryonic stem cells by introducing genes into rat skin cells. The discovery of induced pluripotent stem cells was so significant that he was awarded the Nobel Prize in Physiology or Medicine in 2012 for his work. This is a feat so great that the textbooks of human biotechnology should be rewritten, and it is clear that the ability to regenerate limbs, vertebrae, etc. in lizards is a great achievement of 21st century biotechnology. It is also a tremendous source of hope for burn victims, people who have lost limbs or other parts of their bodies, and people with spinal paralysis. Although embryonic stem cells have had their own bioethical issues, such as the direct use of a woman’s eggs, and the risk of immune rejection when transplanted into a patient, induced pluripotent stem cells are significant because they solve these ethical and technical problems in one fell swoop.
In December 2009, the BBC broadcast a story about eight people who received stem cell therapy and regained their sight. Mr. Turnbull, whose cornea was damaged in one eye by a chemical accident, is a prime example of a direct application of induced pluripotent stem cells. Dr. Francisco Figueiredo and his team at the North East of England Stem Cell Institute (NESCI) in the UK extracted and cultured stem cells from Mr. Turnbull’s normal eye. The stem cells were transplanted into the blind eye, and Mr. Turnbull was able to see again in one eye.
In recent years, stem cell research has become more advanced, revolutionizing the treatment of a variety of diseases. In the 2020s, stem cell therapies have been proven effective and safe in various clinical trials. In particular, the combination of CRISPR-Cas9, a gene editing technology, has made it possible to more precisely control the differentiation process of stem cells. This has broadened the range of diseases that can be treated, and even complex diseases that are impossible to treat with conventional therapies can be overcome with stem cell therapy.
As recently as 2022, a team of researchers in the United States successfully used stem cells to regenerate heart tissue damaged by a heart attack. This gave heart attack patients great hope and opened the door for stem cell therapy to be applied to many more cardiovascular diseases. In 2023, a team of Japanese researchers successfully used induced pluripotent stem cells to regenerate pancreatic beta cells in diabetic patients. This paved the way for diabetics to live a normal life without insulin injections.
However, since research is still very much in progress, there could be side effects that we don’t yet know about. For example, it could cause mutations or other genetic abnormalities, and there is also the possibility of tumors due to the process of genetic modification, which involves the reverse differentiation of somatic cells into stem cells. Therefore, much further research is needed before they can be used safely in patients.
To summarize, stem cells are undifferentiated cells that have the ability to differentiate into different tissues. Since their discovery, there has been a lot of research and development. The history of stem cell research has been focused on solving problems that arise when applying stem cells to the human body. To overcome the biggest problem with adult stem cells, their limited ability to differentiate into different tissues, embryonic stem cells were discovered. To overcome the ethical issues of embryonic stem cells, a new breakthrough, induced pluripotent stem cells, was discovered. Humanity has always pioneered new ways to solve problems, and I believe that the current problems will be solved one day. In the 2020s, researchers are actively combining gene editing technology with stem cell therapy to develop more sophisticated and safer stem cell therapies. Therefore, if it becomes possible to control the differentiation of induced pluripotent stem cells, which is currently impossible, the liberation from disease that mankind has dreamed of will not be too far away.
