What is Stem Cells?

Updated: Jan 7, 2020

Source cells that are found in tissue, blood or organs and have the potential to self-renew, proliferate, and differentiate into tissue or blood cells depending on the needs of the body are called adult stem cells.

The most important characteristic that distinguishes them from all other cells is the ability of these cells to differentiate into various cells according to the need (plasticity). On the one hand, stem cells can symmetrically proliferate by undergoing replication, on the other hand, they can also proliferate asymmetrically. That is, when the stem cell divides, one cell remains as a stem cell, while the other can progress to progenitor cell.

Stem cells are divided into two main groups: embryogenic and non-embryonic stem cells..

Embryonic stem cells:

1-Totipotent stem cells: Totipotent is a word which means undivided, undifferentiated potency in Latin. They are the ancestors of stem cells and all living things. They are the cells that are formed in the first 4 days of the embryogenic life and have the potency to create everything.

2-Pluripotent stem cells: It is the term given to stem cells that show up after the fourth day of embryogenic life. These stem cells are capable of differentiate into about 200 different cell types. The three germ layers (mesoderm, ectoderm, and endoderm) that make up human being emerge from these stem cells.

Adult non-embryonic stem cells:

Multipotent stem cells: They begin to appear in the later stages of embryonic life and create adult stem cells that will exist for life. Multipotent stem cells have the ability to differentiate into blood cells and tissue-specific cells. Its existence was first demonstrated in the bone marrow of an adult in 1976. Over time, its existence has been identified in almost all tissues such as umbilical cord blood, peripheral blood, skin, and dental pulp. Finally, in 2001, it was demonstrated to be abundantly present in adipose tissue. This development has become one of the most important milestones for stem cell therapies. There are 2 main forms of multipotent stem cells

Oligopotent stem cells: These stem cells can be evaluated in the group of progenitor precursor cells. Oligopotent stem cells are capable of differentiating into a closely related family of cells. For example, vascular progenitor cells can differentiate into endothelial or smooth muscle cells according to the need.

Unipotent stem cells: These are progenitor precursor cells that have the ability to differentiate into a single cell type in organs. Endothelial progenitor cells (EPCs) are examples of this group. The first task of these cells is to provide emergency assistance to the cellular damage that occurs in the tissue in which they reside. So as soon as endothelial damage begins, endothelial progenitor cells begin to repair that endothelial region.