Stem cells and regenerative medicine: redefining life! Stem cells are a new breakthrough in the field of regenerative medicine

Some time ago we talked about stem cells, about some definitions and classifications of immune cells and their types. Many of you mentioned a question. Since stem cells are a new breakthrough, a new research, a new discovery in the field of regenerative medicine, what is regenerative medicine?

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Today we will mainly talk about what is regenerative medicine. Let's first understand what is regeneration. In short, the process of re-growing a part of the organism after it is damaged, shed or amputated is called regeneration.

Everyone should have experience with this kind of regeneration, such as hair falling out and growing back, or changing teeth. But it's harder to grow a broken tail like a gecko.

In fact, there are many kinds of regeneration, and simply divided into physiological regeneration and pathological regeneration. For example, the change of teeth, the exchange of old and new red blood cells, including female students who have their period, the cyclical changes in the endometrium, the replacement of skin keratinocytes is molting, are all physiological regeneration. This means that in fact our body can automatically occur regeneration phenomenon, all the time regeneration.

Pathological regeneration is caused by injury and regeneration. For example, wound healing, gecko tail broken regeneration, this regeneration for humans, but often incomplete. You imagine that a gecko grows a new tail and a leg, it's not human, right? What grows out is often non-functional tissue, so it is called incomplete regeneration.

Why can't we humans regenerate a leg? And these animals such as geckos can regenerate? We all know that each individual organism is made up of a single cell. We all know that each individual organism is made up of a single cell. Whether it is a giant tree or a small floating, initially a cell, a fertilized egg, after continuous division and differentiation, but we all know that we can use a branch of a tree to grow another complete tree. But it is difficult to use a puppy's leg to produce another complete dog, so far, the cloning of animals is still a very complex and low success rate of the experiment. Theoretically, any cell of an organism has the potential to develop into a complete biological individual, which is called totipotency.

What do we mean by cellular pluripotency? We used to give this definition in medicine, in this international organization: the totipotency of a cell as some special characteristic. The cell with this ability, which retains the ability to form all cell types of the organism, is cellular totipotency. A cell with totipotency is one that possesses the ability to develop into an individual organism. In the case of plants, almost all cells have totipotency. But for animals. Only fertilized eggs and some embryonic stem cells have pluripotency. Only through nuclear transplantation is it possible for an adult cell of an animal to acquire totipotency and thus obtain a clone of itself.

So why does a cell have totipotency? Because each cell contains the nuclear genes contained in this organism, and these genes contain almost all the genetic information of this organism, which is called the totipotency of the cell. So why is it that only plants can rejuvenate? Actually, no, all building block organisms, including plants, corals and mosses, are able to rejuvenate. Because their bodies are individuals composed of a set of constructs. It can be formed repeatedly through its basic structural units, and further development of its tissues and organs in various parts is changeable. Why can't animals? This is actually still a mystery. We will talk about this mystery in the next lesson.