Papers on Introduction to Life Sciences

Research progress of human embryonic stem cells

Everyone has been familiar with life science for a long time. We talked a lot about biopharmaceuticals, genetic engineering, protein, enzymes, antibiotics, interferon in high school biology textbooks. The frontier of life science and human health mainly studies the frontier science, that is, the science still in the research stage. In real life, there are many hooligans. For example, watching relatives and friends leave, we can't get rid of the dependence on antibiotics, so we have to look for safer and more humanized treatments and breakthroughs in key technologies! This is what the frontier technology research of life science will bring to mankind.

I am very interested in this course. Because I can't cover everything, this time I mainly express my views on the research and development of human embryonic stem cells.

Definition: Embryonic stem cells refer to inner group cells when fertilized eggs divide and develop into blastocysts. They have the characteristics of infinite proliferation, self-renewal and multi-directional differentiation in vitro. It is generally believed that totipotent stem cells should have the following characteristics: (1) originated from totipotent cell population; (2) Chromosome karyotype is normal; (3) Immortality, infinite division in embryonic state; (4) Cultured cell lines can spontaneously differentiate into extra-embryonic tissues and somatic cells belonging to all three germ layers in vitro or in teratomas.

Where is the magic of stem cells? As we all know, our 100-kilogram body was originally just a cell made by our parents-a fertilized egg formed by the combination of a sperm and an egg. After that, one cell becomes two cells, two cells become four, and four cells become eight. Where the eyes are long, it differentiates into all the cells that make up the eyes, and where the arms are long, it differentiates into all the cells that make up the arms. When a complete person is formed, most of the cells that make up his body no longer have the ability to differentiate. Whether in vitro or in vivo, embryonic stem cells can be induced to differentiate into almost all cell types in vivo.

At present, what we hear most is that embryonic stem cells are used for the treatment of leukemia. Generally, leukemia patients need to find bone marrow suitable for transplantation. Now most of them are only children, and the probability of bone marrow matching between two unrelated people is almost one in 100 thousand. At this time, trouble comes. If the baby is born with umbilical cord blood, and the hospital has established an embryonic stem cell bank for everyone, then once you get this disease in the future, you can directly extract your own stem cells from it, differentiate them into hematopoietic stem cells through tissue culture, and then transplant them into patients, so that rejection can be avoided and there will be no trouble in treating these. In fact, the application of embryonic stem cells is not limited to this, but also can be used to treat Parkinson's disease, such as stroke, arrhythmia, myocardial infarction, retina, diabetes, liver dysfunction, arthritis and so on. Human embryonic stem cells can also differentiate into trophoblast cells, nerve cells, glial cells, hematopoietic cells, myocardial cells and so on, so their medical application prospects are huge.

The biggest advantage of embryonic stem cell transplantation is to avoid rejection, but adult stem cells are not as good as embryonic stem cells. Stem cells extracted from bone marrow can differentiate into primitive cells, such as bone marrow tissue cells, until they grow into other tissues or organs as needed. Results Bone marrow stem cells differentiated smoothly at first, but eventually did not differentiate into primitive cells, but produced strange cells similar to human tumors. Although embryonic stem cells have many uses, it is very difficult to separate and purify them. Before we isolate stem cells, that is, before these cells differentiate, we separate them from the inner cell mass and then put them in the incubator for culture. In fact, this is a complete scam, that is, we extract cells from the microenvironment that the inner cell mass is used to, and put them into a culture machine, which puts a lot of substances in it, so that these cells think that they are actually in the original position or in the inner cell mass. So this is a complete scam. Those cells thought they were still in the cell mass, so they continued to wait for the signal to make their next division. Of course, in addition to separating them, some techniques can be used to prevent these cells from separating, so that cells can continue to culture and culture. Moreover, these cells will not age or die because of the technology we adopt, and they will continue to develop in our culture machine day after day.

1. How to maintain cell totipotency and control the transformation to special cells? That is, how do we make embryonic stem cells develop into hematopoietic stem cells instead of developing into nerve cells or a complete individual? In fact, stem cells in our body will differentiate into all cell types in our body, and about one stem cell tends to differentiate into more than 200 cell types in our body. Our problem is how to make this stem cell differentiate into the cell type we need, such as brain cells, myocardial cells or combined cells. The current research results show that embryonic stem cells are cultured in different media, so they will develop into cells with specific functions. For example:

Embryonic stem cells-culture of fetal bovine serum bone marrow stromal cells-hematopoietic cells

Embryonic stem cells-gene transfection-insulin secreting cells.

Embryonic stem cells -RA- neurons.

Although some directional transformation has been realized, the configuration of these media and more problems about directional differentiation need to be solved, which are the problems we are studying at present and need our generation or the next generation to continue to study.

2. The next problem to be solved is whether differentiated cells are carcinogenic. The medium for culturing embryonic stem cells in vitro contains many chemicals. Although the environment inside is similar to that of human body, it is not exactly the same in human body. So the substances in the culture medium will cause embryonic stem cells to become cancerous, activate proto-oncogenes and develop into cancer cells? This is also to be solved and needs to be further studied in the future development.

3. Ethical issues: The source of embryos used for hepatocyte research is very difficult. Embryo is the life of the future, and life cannot be stifled by scientific research. Moreover, the research of embryonic stem cells is still in its infancy, and there is still a long way to go before clinical trials, let alone for treating diseases. "We can't cruelly experiment on some embryos because they can't develop into life. Supporters point out that it is right to use some discarded embryos to expand stem cell research on a voluntary basis. Stem cell research is regarded as the hope of finding new treatments for neurological and brain diseases such as Alzheimer's disease and Parkinson's disease. There is also the issue of cloning. The birth of Dolly the cloned sheep has made more people participate in this debate. If human stem cells are used to clone human beings, whether it should involve ethical issues or not involves the bottom line of people's moral tolerance.

Research trends of embryonic stem cells;

To improve the culture conditions of embryonic stem cells in vitro and establish a more effective and simple method to obtain embryonic stem cells.

Directed differentiation into specific types of cells is used to treat clinical diseases and solve the problems of immune rejection and potential tumors.

Lateral differentiation ability of adult stem cells and its comparison with embryonic stem cells. Can adult stem cells replace embryonic stem cells?

Research prospect of human embryonic stem cells;

Future Regenerative Medicine Science and Technology Daily June 5438+February 3, 20041:Through the microscope, people found that there is a mysterious thing in the human body, which shines like a wonderful "star" in the Milky Way, releasing mysterious brilliance. These fascinating "stars" are human embryonic stem cells. Although the current medical technology cannot bring some patients back to life, the means of regenerative medicine may prolong or regenerate human life, thus achieving the goal of incomplete extinction of species. Although this is a good thing for life, the attempt to extract embryonic stem cells from human fertilized eggs has involved scientific, religious and political circles in an endless debate and caused an uproar around the world.

With the unique control mechanism 1998, Thomson of the University of Wisconsin in the United States took the lead in successfully isolating and cloning human embryonic stem cells and establishing cell lines. This research result immediately caused a sensation in the world and became the focus of world attention. Because human ES cells have the general characteristics of other mammalian ES cells, they can differentiate into any tissue that constitutes the human body under suitable conditions. Therefore, human ES cells can provide a reliable cell source for tissue engineering research, and also play an important role in human early embryogenesis, cell differentiation and gene regulation.

The significance of human embryonic stem cell research;

The application prospect of embryonic stem cells is very encouraging. Embryonic stem cells can be used as a new method to study human embryonic development, birth defects and embryonic tumors. It can be used for methods that have not been implemented so far; Make human disease models for basic research, drug development and toxicology research. If cloning technology can obtain stem cells from patients' own tissues, it can solve the problem of tissue shortage for treating degenerative diseases and end the use of immunosuppressants in transplantation treatment. In addition, stem cells can also be used as a new gene delivery system for gene therapy. In a word, its prospect is very broad.

Conclusion: Embryonic stem cells have a very attractive prospect in revealing the mysteries of life and overcoming various intractable diseases. Although there are still many difficulties and controversies, every progress in the field of human embryonic stem cell research will make a great contribution to human development if we can correctly guide and establish a corresponding and perfect supervision mechanism.

The research and application of stem cells in China have already had a certain foundation. As early as 1960s, the research of bone marrow stem cell transplantation began. At present, hematopoietic stem cells are the most widely studied and applied. 1992, the first unrelated donor registration group for bone marrow transplantation in Chinese mainland was established in Beijing, and the "China Bone Marrow Bank" also officially accepted donations. In 2002, Beijing established a cord blood stem cell bank. At present, there is no clear legal regulation on the research of embryonic stem cells in China.

There is still a gap in stem cell research between China and other countries, which needs to be fought for by generations of China people. At the same time, stem cell research in the world is still purely in many "black hole" fields. How to reasonably apply stem cell research results without violating ethics is also a controversial topic in the world. Therefore, the research of human embryonic stem cells still has a long way to go.