What are stem cells?
Stem cells are undifferentiated (or unspecialized) cells that are capable of renewing themselves indefinitely. This undifferentiated state means that a single stem cell has a unique capability to grow and generate a wide variety of specialized cell types (e.g., muscle cells, neurons, heart muscle cells, etc) under the right physiological conditions.
They have the potential to provide us with a renewable, and virtually unlimited, source of cells to repair or replace damaged or diseased cells and tissues.
Embryonic Stem Cells
Embryonic stem cells are derived from a very early stage embryo known as a “blastocyst” - a cluster of cells that resemble a hollow, microscopic sphere. Unlike adult stem cells, which are restricted to producing limited cell types, embryonic stem cells have the potential to generate every cell type in the body.
Stem Cells from Adult Tissues
Stem cells have now been uncovered from adult tissues as diverse as skin, hair follicles, blood vessels, liver, the digestive tract and the nervous system. They can have different properties depending on their tissue or organ of origin, but are less flexible than embryonic stem cells. Generally, they only produce the type of cells found in their tissue or organ of origin.
Hematopoietic stem cells
These adult stem cells can be found in the bone marrow, as well as in the umbilical cords of newborn babies. In normal conditions, they continuously produce new blood cells and immune cells. They are relatively easy to obtain and have been used in medical treatments for over 30 years. Currently, they are used to treat patients with leukemia.