Spinal cord injuries can result in partial or full paralysis, depending on how extensive the damage is and the injury's location. When the nerves in the spinal cord are damaged, conventional medicine does not have a way of repairing them. Stem cell therapy for spinal cord injury is a controversial option that has the potential to heal nerve damage.
The spinal cord contains the nerves by which the brain communicates with the rest of the body. Just as an appliance cannot work if someone cuts its power cord, the brain will not be able to communicate through damaged nerves in the spine. The part of the spine that contains the damaged nerves will be the point below which the individual could become paralyzed, as nerve impulses will no longer be able to pass through those nerves.
Stem cell therapy for spinal cord injury works by reestablishing the severed nerve connections in the spine with new nerve cells. Doctors do this by injecting stem cells into the damaged area of the spine. These are cells that are what scientists call pluripotent, meaning they are undifferentiated cells that can become any kind of cell in the human body. When these undifferentiated stem cells are placed with cells of a particular type, they transform themselves into that kind of cell. Therefore, when stem cells are injected into an area containing nerve cells, they will turn into new nerve cells. These new nerves can recreate the connection between the part of the spine above the injured area and the part of the spine below the injured area.
This therapy has the possible benefit of helping cure paralysis due to a damaged spine, but the use of stem cells makes it a controversial topic. One source of these stem cells is fertilized human blastocysts, the stem of cells that grows into an embryo, that laboratories create from donated eggs and sperm. These embryonic stem cells are removed from the blastocyst, and scientists allow the individual stem cells to continue dividing into new stem cells. This process eventually creates large stem cell lines for use in research or medicine. Many individuals say that using these stem cells is immoral because they believe that harvesting stem cells from a human blastocyst is the moral equivalent aborting a human fetus.
Research is uncovering new sources of adult stem cells that doctors could use in stem cell therapy for spinal cord injury. These are stem cells that are present inside the adult body, such as in bone marrow, and not harvested from blastocysts. Since these stem cells come from an individual's own body, their use does not attract the kind of controversy that surrounds the use of embryonic stem cells.