Nowadays, researchers and scholars all over the world are exploring how to utilize stem cell therapy to overcome the problems of spinal cord injuries, Parkinson's disease, macular degeneration, diabetes, cancers, uremia, and blood disorders that are plaguing the medical field. The enormous potential of stem cell research has been supported by countries all over the world, and many of them are vigorously developing stem cell technology in order to occupy the high ground in the field.
Regenerative medicine has become the focus of attention of the international biology and medicine communities. With the increasingly fierce competition in this field, the global stem cell market is gradually expanding, and stem cell technology has gradually become an important indicator of the development level of life medicine.
Current Clinical Applications
In 2011, the Chinese Academy of Sciences (CAS) launched the "Stem Cells and Regenerative Medicine Research" strategic pilot science and technology program. Stem cell special from the major theoretical breakthroughs, key core technology and stem cell clinical application of three aspects, focusing on tackling stem cell regulation, stem cell therapy core mechanism, stem cell application system and other major scientific issues and core key technologies, vertical connection between the basic theory of stem cell research and clinical translation and application, for the research and development of stem cells and regenerative medicine to play a leading role in the role of demonstration. Until now, we have achieved a lot of milestones, such as the repair of some organ damage, bone marrow damage, nerve tissue repair, and the treatment of some cancers, and even in the treatment of AIDS, pulmonary fibrosis, severe liver disease, and other "terminal illnesses" in the field of breakthrough progress.
Currently, there are five applications of cellular technology in clinical medicine: cell replacement therapy, system reconstruction, tissue engineering, gene therapy, and beauty and anti-aging.
Cellular Replacement Therapy
In recent years, stem cell-based cellular replacement therapy has made some progress in the treatment of disease. In clinical and scientific research, scientists have successfully utilized inter-embryonic stem cells, mesenchymal stem cells, neural stem cells and other stem cells to repair and treat premature ovarian failure, Parkinson's disease and diabetes. This field is currently a breakthrough progress.
System reconstruction
The use of hematopoietic stem cells and mesenchymal stem cells can rebuild the body's hematopoietic system and immune system, which can become a conventional treatment for leukemia, aplastic anemia and other blood diseases, and immune system defective hyperactive diseases.
Tissue engineering
Tissue engineering, is the use of artificial methods in vitro to make (construct) a piece of tissue, and later its scope was extended to the use of artificial methods in vitro organ construction. Tissue engineering research mainly includes four aspects: seed cells, biomaterials, methods and techniques for constructing tissues and organs, and clinical applications of tissue engineering. Currently, there are three common clinical approaches to tissue repair: autologous tissue transplantation, allogeneic tissue transplantation, or the application of artificial substitutes. Through the collection of adult stem cells, in vitro environment artificial culture to form a number of tissues and organs, in the return to the body, used to replace the human body diseased tissues and organs, the culture of the formation of the tissues and organs can also be used as a disease model and drug testing model.
Gene therapy
Gene therapy refers to the introduction of exogenous normal genes into target cells to correct or compensate for diseases caused by defective and abnormal genes to achieve therapeutic purposes. It also includes technological applications such as transgenics. Stem cells as the ideal target cells for gene therapy, firstly, isolate the patient's stem cells, genetically modify them in vitro, and introduce normal genes into the stem cells; and then, the modified stem cells are intravenously infused back into the patient's body, so that the normal genes can be stably expressed in the body, and play a role in preventing and curing the disease.
Beauty and anti-aging
"Adult stem cells" shoulder the role of replenishing tissue cells, when the cells age and die, the stem cells themselves differentiate and renew themselves to replenish. However, the number of stem cells decreases with age. Stem cell deficiency and aging are important causes of aging of tissues, organs and even the whole organism. The multi-directional differentiation and repair ability of stem cells can constantly renew and replace the aging cells in the body, and also promote the continuous proliferation of cells, so as to constantly replenish the body with healthy and fresh cells, and make the body radiate youthfulness from the inside out.
Problems with stem cell technology
Although stem cell technology has made significant breakthroughs, there are still many problems that affect the application of stem cell technology.
01 Stem cell culture
Stem cell culture conditions are the foundation of stem cell technology, and the environmental requirements for routine stem cell culture are extremely harsh. Although researchers have reported a simple and efficient method of culturing i PS cells without using trophoblast cells and animal serum, and reducing the risk of infection during transplantation, simplifying, perfecting, and standardizing the culture conditions remains a major challenge for scientists. However, simplifying and standardizing the culture conditions remains a major challenge for scientists.
02 Ethical Issues
Since the birth of the cloned sheep Dolly in 1996, embryonic stem cell research has involved ethical, religious, moral, legal and other issues, there are controversies, seriously impede the development of stem cell technology for the treatment of human diseases. i PS cells achieve the induction of mature somatic cells into differentiated stem cells, so that the technology is no longer subject to the ethical issues faced by ES cells. cells.
03Regulators and mechanisms of induced differentiation
The regulators and mechanisms of stem cell induction are not yet clearly understood. To induce a certain type of tissue or organ, it is necessary to understand the mechanism of action of various cytokines and the period of their action, or else we may obtain a dysfunctional organ or tissue. In addition, there is insufficient evidence on the mechanism and differentiation direction of stem cells involved in injury repair, and there is widespread concern about the false-positive problem of myocardial regenerative stem cell therapy and the controversy over the contribution of c-kit-positive cardiomyocyte stem cells to myocardial regeneration in recovery of cardiac function.
04Targeted induction
There are many uncertainties in inducing stem cells in vitro or in vivo to differentiate into tissue-specific cells, or in transdifferentiating somatic cells into other cell types via mesodermal cell states, especially in tissues and organs with a complex cellular pedigree such as the kidney and the heart. It is difficult to ensure differentiation of cardiac progenitor cells into functional ventricular cardiomyocytes using stem cell therapy, as well as delivery and integration of differentiated cells into the patient's ventricular myocardium, making it difficult to target them to form tissues or organs.
05Tumor induction
Some foreign scientists have found that transplantation of a mixture of undifferentiated cells can lead to tumors, and that some of the induced cells exhibit tumorigenicity during transplantation. At present, the inducing factors used are Oct4, Sox2, Klf4 and c-Myc, but some inducing factors, such as c-Myc, although inducing the differentiation of stem cells, but increase the frequency of tumors, which may be tumorigenic to human stem cells.
06Induced senescence of organs and tissues
The tissues or organs obtained by stem cell induction, although new in morphology and structure, are synchronized with the senescence of the genetic material in their nuclei, and the organs or tissues generated by induction with the patient's cells are unable to ensure normal function.
07Immune rejection
The bottleneck in stem cell therapy is immune rejection after transplantation. i PS cells were thought to solve the problem of immune rejection of ES cells, but there are reports of autoimmune reactions induced by i PS cells. Although immunosuppressive drugs can be used to suppress rejection after cell or organ transplantation, long-term use of immunosuppressive drugs is associated with significant toxicity and other side effects.
With the deepening of stem cell science, the rapid development of stem cell technology, and the improvement of stem cell regulations, stem cell technology will be more and more widely used in stem cell transplantation, new stem cell drugs, stem cell tissue and organ repair, etc., and its indications will increase year by year, which will become an important force in solving the unmet needs of the clinic, and bring new hope for the treatment of many diseases for which there was no other way in the past. This will bring new hope for the treatment of many diseases that have been left untreated in the past.