Stem cells are defined as cells that do not have specific tissue characteristics, maintain their undifferentiated phenotype until the appropriate signal is received, and have the ability to self-renew and proliferate.
Since the existence of human beings, one of their biggest goals has been to find solutions to diseases and extend life. There is information that the mixture obtained from many different plants was used in treatment thousands of years ago. B.C. It is known that various diseases and treatments are described in a papyrus thought to date back to 1534. Humanity’s subconscious desire to achieve immortality has been the driving force of medical science to date.
Especially in the last 20-30 years, tissue engineering has progressed rapidly all over the world and at this point, tissues and even 3D organs can be produced from human stem cells in the laboratory environment. Taking a person’s own cell and producing a cell, tissue or organ to be applied to him/her (autologous); It can treat many diseases that the pharmaceutical industry is inadequate for and connects the patient to life.
Stem cells, which have the ability to renew themselves and transform into different cells, are divided into three types according to their division and differentiation characteristics.
As we know, life for mammals begins with a single cell called zygote (sperm fertilizing the egg). This cell is a totipotent cell and carries all the functions needed for the formation of an adult organism. A totipotent cell alone can form a living thing. It maintains this feature for 4 days after fertilization. Totipotent cells are not used in human therapy for ethical reasons.
When embryonic stem cells are mentioned, we mean pluripotent cells obtained from the inner cell mass of the blastocyst. These cells have the ability to differentiate into three embryonic germ layers. The three germ layers make up more than 220 cell types in an adult. Some differentiated pluripotent cells can exist as multipotent cells in adults (e.g., in the bone marrow), but these cells have limited ability to differentiate. Embryonic stem cell research is one of the most important topics in regenerative medicine due to their unlimited ability to renew themselves and plasticity (transformation into different cell types).
Adult stem cells have the ability to transform into the organ or tissue from which they were obtained, and they are called multipotent stem cells. Multipotent stem cells; They are undifferentiated cells found in differentiated tissues in adults that have the ability to renew dead or damaged cells. They are also called somatic stem cells. They are found in tissues such as bone marrow, muscle, eyes, nerves, liver and skin. They have the ability to divide and renew themselves. In adults, stem cells in the same number and potential are not found in every organ and tissue. For example, there are very few these cells in the brain. For this reason, in brain damage, there is no organ regeneration like a bone or tissue; the damage is usually permanent and has serious consequences. Multipotent stem cells constitute the stem cell group used in the field of treatment.
*Mesenchymal and fat-derived stem cells (SVF) are the most commonly used in the field of cellular therapies.
