What is a stem cell?
A stem cell is truly remarkable. Every organ and tissue in our body grew out of a cluster of stem cells early in development. And unlike any other cell in the body, a stem cell has the unique ability to renew itself. It can divide and multiply into many more just like it.
This means stem cells can repair and replace tissue in the human body. In other words, they have the power to heal.
Think of your skin. The tissue in your skin needs constant renewal that could not take place without stem cells. Or muscle—stem cells in our muscles are responsible for repairing damaged tissues when we sustain an injury.
There’s something else
Early in life, stem cells are even more remarkable. They have the extraordinary potential to develop into any other type of cell in the human body.
They start in the embryo as unprogrammed cells that then become specialized to create bone, muscle, skin, the brain, and over 250 other types of specialized cells. These are called pluripotent stem cells and their potential is staggering.
Using stem cells to save people
Researchers have found that stem cells can be used to treat disease and injury. They can actually stimulate the body to repair itself.
For example, you probably have heard about bone marrow transplants that have been taking place now for more than 30 years. These procedures rely on transplanting stem cells derived from bone marrow and have dramatically altered the treatment of blood disorders and certain cancers such as leukemia.
In the past 15 years, significant new discoveries have emerged. Breakthroughs that the original discoverers of stem cells never dared dream about. Researchers are finding ways to use stem cells to rebuild many parts of the body where it has been damaged—for example, in the eye, in the pancreas, and in the brain. Cures or revolutionary treatment for blindness, MS, stroke, and spinal cord injury are already in clinical trials and new trials are around the corner.
Sources of stem cells
Much of the public discussion around stem cells has focused on where stem cells come from. Adult stem cells can be found in specific tissues in our bodies. As mature cells, they are already specialized to perform certain functions and are somewhat more limited in their application for therapeutic purposes. They can generally make only the kind of cells found in the tissues where they reside.
On the other hand, embryonic stem cells—derived from five-day old blastocysts that are precursors to embryos—are pluripotent in nature. They are capable of generating any kind of cell in the body, any kind of tissue. And this is why they are of such value to scientists doing both basic research in the lab and medical research in the clinic. They have the potential to regenerate tissue and cells that have been lost due to disease or injury.