Stem Cells - Types & Clinical Application

Stem cells are the unspecialized/undifferentiated cell that has the ability to divide and generate more of the same type of stem cells. These are self-renewing population of cells that acts as a source from which production of the differentiated cell takes place. Depending on the capability to differentiate into other cells there are three types of cell.

• Totipotent Cells: Unlimited capability and also these cells can form extraembryonic membrane and tissues. In other words, these cells can generate a fully functional organism.
• Pluripotent Cells: They can differentiate into all cell types such as inner mass cells.
• Multipotent Cells:  They form those cell who have a specific function, eg; Blood Cells etc.

In mammals, there are two broad types of stem cells.

1. Embryonic Stem Cells:  These cells are defined by their origin. They are isolated from the inner mass of the blastocyst. They are pluripotent and can become all cell types of body.
2. Adult Stem Cells (Somatic Stem Cells):  They are mostly pluripotent and can be found in various tissues. Source of adult stem cells are Bone Marrow, Adipose Tissues,  and Blood. The stem cells are extracted or isolated from these locations by various processes. In Bone Marrow, they are extracted by drilling into bone ( femur or iliac crest). While in Adipose Tissues stem cells can be isolated by Liposuction (Removal of fat). Adult stem cells are required to be isolated from Blood cells through Apheresis. 

• Apheresis is a process in which blood is drawn from the donor and passed through a machine that extracts the stem cells and other portions of blood are returned to the donor.

Other than these three sources stem cells can also be collected from Umbilical Cord just after the birth of a child. The extraction of stem cells from the umbilical cord is named as Autologous Harvesting, in which autologous cells are obtained from one's own body for surgical processes.

Clinical Application

Stem cells are used to treat various diseases or conditions, Bone Marrow transplantation is used for many years without any obstacles. Bone Marrow is a location where adult stem cells are found in large quantity and can be used for the treatment of Liver Cirrhosis, Chronic Limb Ischemia, and Endstage Heart Failure.

Adult Stem Cells have been successfully used in the treatment of Leukemia, Bone and Blood Cancer.