Adult vs Embryonic Stem Cells
The cells, which are capable of continued division and are differentiated into different forms of cell types, are known as ‘stem cells’. These cells are found within different tissues of the animal body at all stages of life, before and after birth. Normally the stem cells are incapable of carrying out specialized functions, but they do have the ability to produce specialized cells like red blood cells, nerve cells etc. Apart from that, the stem cells are also capable of maintaining or expanding the number of stem cells or self-renewal. The stem cells vary, depending on their location in the body and the type of the cells they can differentiate. There are two different types of the stem cells, namely, adult stem cells and embryonic stem cells. The stem cell that can give rise to any tissue in an organism is called ‘totipotent’. The stem cells that can give rise to all the cells in the body are called ‘pluripotent’, while the stem cells that can produce a limited number of cell types are called ‘multipotent’. The stem cells that can give rise to only a single cell type such as sperm cells in males are known as ‘unipotent’.
Adult Stem Cells
Adult stem cells are found in the tissues of children and adults. It is believed that an adult individual contains 20 different types of stem cells. Out of them, there are two types of adult cells, namely, hematopoietic stem cells and mesenchymal stem cells, which can be easily obtained from bone marrow. The Hematopoitic stem cells are also readily available in umbilical cord blood. Other than these two adult stem cells, isolation of all the other stem cells from the body is far more difficult owing to an extremely low number of cells. This reason limits their use for wider clinical applications.
Embryonic Stem Cells
Embryonic stem cells are only present in early embryos and produce differentiated cells during the fatal development. After 5 to 9 days from post fertilization, the human embryo is called ‘blastocyst’, which contains about 100 to 200 cells. The embryonic stem cells can be obtained from the centre of this blastocyst. The Embryonic cells can be easily grown in culture and are widely used to test drugs. Since these cells are capable of producing any cell type in the body, they are used in therapies.
What is the difference between Adult and Embryonic Stem Cells?
• Embryonic stem cells are present only in very early embryos whereas adult stem cells are present in tissues of children and adults.
• Since the embryonic cells are unspecialized cells, they have the potential to develop into any cell type. In contrast, the adult stem cells are only capable of producing into tissue specific cell types.
• The adult stem cells are difficult to grow in culture. The Embryonic stem cells, in contrast, can be easily grown in culture.
• Unlike the adult stem cells, the embryonic stem cells can multiply indefinitely resulting in a very large number of daughter cells.
• The Embryonic cells can be easily obtained from the early embryos while the adult cells are very rare so that they are difficult to obtain from the body.
• The Embryonic stem cells have more potential to become cancerous while the adult stem cells have less potential to be so.