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How far can stem cells make us rejuvenate?
How far can stem cells make us rejuvenate? Immortality has always been the eternal pursuit of mankind.
In the 1970s, scientists discovered that after each round of DNA replication, a piece of DNA was lost at the end. This is called telomere, which, like a safety helmet, guarantees the integrity of the DNA sequence through self-sacrifice. But if there is no compensation mechanism, after thousands of generations of replication, DNA will eventually shorten or even disappear, resulting in two consequences-aging and tumors. Scientists have discovered that a substance called “telomerase” plays a decisive role in maintaining or even extending telomere length.
Recently, scientists at National Taiwan University, Nankai University, and the University of Michigan have successfully obtained pluripotent stem cells with extended telomeres and true developmental pluripotency from somatic cells in mice that lack heterozygous telomerase through somatic cell nuclear transfer. This result shows from both the experimental and theoretical levels that the “rejuvenation” of human beings is no longer a dream.
From the ancient elixir of immortality to the beauty remedies of modern people, rejuvenation or immortality has always been the eternal pursuit of mankind. Even scientists have spared no effort to study the method of “borrowing from heaven for another five hundred years”. In these studies We can always see stem cells, so what is the relationship between stem cells and aging? Is it a key to reverse growth?
What is aging? What is the nature of aging? Aging is the eternal rhythm of life. Whitening of hair, loss of teeth, appearance of wrinkles… This is the aging that we can see, and the decline of internal organs, slow response, poor memory, weakened resistance… This is the aging that we can’t see. The degeneration of tissues and organs and decreased function of human body aging is essentially the attenuation of cells, and the attenuation of cells is mainly caused by the attenuation of stem cells. Therefore, Han Zhongchao, director of the National Stem Cell Engineering Technology Research Center, said: “The essence of aging is actually the attenuation of stem cells.”
People can live to be 100 years old or longer, and individual somatic cells often do not have that long lifespan. For example, epithelial cells are replaced every 27 to 28 days, and intestinal mucosal cells are replaced every 2 to 3 days. Mature somatic cells in the body will die due to aging or injury and need to produce their substitutes at any time, and stem cells are the source of these substitutes. During the development of the human body, they will maintain their naive state and differentiation potential for a long time.
When they are subjected to some special physical and chemical stimulations, they will become active, begin to proliferate and differentiate, become the cell type needed by the body, and play their due role. . It’s like some small children hiding in a crowd, usually staying there quietly. Once the body needs them, they can quickly become more and grow up, become adults, and work like other adults.
According to their proliferation and differentiation ability, Stem cells can be divided into:
- pluripotent stem cells,
- sub-pluripotent stem cells,
- pluripotent stem cells, and multipotent stem cells ;
According to their tissue source, they can be divided into:
- embryonic stem cells,
- placental umbilical cord and other perinatal stem cells,
- bone marrow stem cells, cardiac stem cells, etc.
- Tissue stem cells;
According to their physiological functions, they can be divided into:
- neural stem cells,
- vascular stem cells,
- skin stem cells, etc.
Under ideal circumstances, these stem cells can sustain our lifelong needs. But the reality is cruel. Li Yukui, the chief scientist of the Ningxia Human Stem Cell Research Institute, pointed out that the consensus in the field of stem cell research through these years of research is that as people age, the activity and regenerative capacity of many stem cells in the human body are also decreasing. Insufficient supplementation of new-born cells, senescent cells can not be replaced in time, resulting in the decline of the functions of the system.
(sourceinternet, reference only)