Hi guys, today I’m going to talk about stem cells, which I have recently studied at school.
Stem cells are primitive undifferentiated cells with the ability to transform into various other types of cells of the body through a process called “differentiation”. They can also divide (through a process called “mitosis”) to produce more stem cells. In the early stages of human development, stem cells, which are located in the embryo, are different from all existing types of cells in the body.
A cell, in order to be defined a “stem”, must satisfy the following properties:
- Self-renewal: the ability to replicate indefinitely maintaining the same level of differentiation
- Potency: the capacity to differentiate into specialized cell types
According to potency we can distinguish four types of stem cells:
- Totipotent: a totipotent stem cell can develop into an entire organism and even in extraembryonic tissues.
- Pluripotent: a pluripotent stem cell can specialize in all types of cells that are in an adult organism, but not in cells that make extraembryonic tissues.
- Multipotent: a multipotent stem cell can specialize only in some types of cells
- Oligopotent: an oligopotent stem cell can specialize only in a few types of cells
- Unipotent: a unipotent cell can specialize only in one type of cells.
Stem cells can also be classified according to the source of derivation:
- Adult stem cells: are unspecialized cells found among specialized cells of a specific tissue. They are mostly multipotent.
- Embryonic stem cells: are cells obtained from the inner cells of a blastocyst.
- Fetal stem cells: are multipotent cells present in the uterus, during the development of the fetus. They’ re obtained from aborted fetuses
- Amniotic stem cells: are stem cells that are found in the amniotic fluid that surrounds the fetus during gestation. The amniotic stem cells have biological characteristics very similar to embryonic stem cells, but do not have ethical contraindications linked to the destruction of the embryo.
Stem cells are stored in the so-called cryopreservation banks, which are facilities with high standards of safety, where the cells collected are stored in large containers of cryogenic nitrogen until their use. The stem cells can be kept immersed in liquid nitrogen or vapor nitrogen at -170 / -190 ° C. The cells are preserved because it is expected that in the future they will be used to cure lymphoma, leukemia and cancer.