According to Dr. Huang of Microbiology and Molecular Genetics at Rutgers University, stem cells can be divided into three levels (3R), namely, replacement, repair and regeneration.
Replacement: Stem cells can differentiate into cells with specific functions and can replace dead cells in damaged areas. Repair (repair injured but not dead cells): repair damaged but not dead cells with growth factors, cytokines and exosomes secreted by stem cells. Regenerate (autologous cell regeneration): Because the number of imported stem cells is limited, it is the fundamental purpose of treatment to use exogenous stem cells to arouse the regeneration function of damaged parts and promote the self-growth of cells. Among them, stem cells need foreign bodies to play a role in repair.
Garbage turns into gold! Foreign bodies have three advantages. So, what is a foreign body? Zhang Yiwen, Ph.D., Institute of Biochemistry, Yangming University, explained that in the process of cultivating stem cells, scientists found many foreign bodies in the culture medium, which were filled with these foreign bodies like small bubbles. In the past, people thought that foreign bodies were just wastes of cell metabolism, but Zhang Yiwen said that foreign bodies actually had three advantages.
Small molecule: the average size of foreign body is about 30 ~ 100nm, which belongs to glutinous rice grade. Because the molecules are small, they are easily absorbed. Lipid bilayer: Due to the structure of lipid bilayer, it is easy to be compatible with other cells and can bring some regeneration and repair effects to the body. Transmission of information between cells: The biggest function of foreign bodies is to transmit messengers between cells. For example, when skin cells are abnormal, they will release foreign bodies, send messages to other cells that need rescue, and let healthy cells go to the problematic places for regeneration and repair.
Du, the inventor of Du's knife technique, used foreign bodies to assist nerve reconstruction, and Du, the president of Yida Hospital, used Du's knife technique to save paralyzed patients. In recent years, he even began to combine cell therapy to help patients rebuild nerve cells.
At present, Schwann cells or mesenchymal stem cells are injected into nerve injury in animal experiments around the world. Du Yuankun first used exosomes obtained from nasal stem cells to help cells in vivo transform into an environment conducive to nerve growth. Then Schwann cells or mesenchymal stem cells are added into fibers to make strips to repair nerve injury, or a membrane is made to cover nerve injury. In animal experiments, this method can make the broken nerve regrow and restore some functions.
"Chicken Soup Theory" explains the relationship between exosomes and stem cells. Du explained that foreign bodies can be considered as chicken soup and chicken essence, and stem cells are chickens. After proper treatment, the nutrition actually adds chicken soup or chicken essence, which shows the importance of exosomes.
For example, in recent years, he has also cultivated cells that can promote nerve cell regeneration through nasal stem cells. Because the cell types of nasal stem cells are similar to those of nerves, exosomes and miRNA in the screening are implanted in culture to repair damaged nerve cells, and combined with "spinal nerve bypass reconstruction surgery", the postoperative effect is higher.