Stem cells have the ability to grow into many different types of cells. They have the capability to be used in a wide variety of treatments that require tissues and organs to be replaced. Researchers hope that stem cell treatment applications will include spinal cord injuries, conditions related to Parkinson's disease, and brain injuries. Hematopoietic stem cells (HSC) are currently the only stem cells that are regularly used as a stem cell treatment — most commonly in bone marrow transplants. HSCs are responsible for the production of all blood cell types.
A bone marrow transplant is the most common form of stem cell treatment, and is given to patients who suffer from an immune system or blood disorder. Leukemias are diseases that affect the blood-forming organs and bone marrow. The cells of these tissues begin to malfunction causing deleterious effects. To treat the condition, radiation therapy is used to kill off the problem cells and the tissues are replaced with new bone marrow.
Living donors are needed for bone marrow stem cell donations. When a patient needs a bone marrow transplant for leukemia, or other immune system or blood disorders, the physician will first have willing family members tested to see if there is a suitable match within the family, by comparing Human Leukocyte Antigen (HLA) characteristics. HLA is the primary histocompatibility complex in humans. The histocompatibility complex is the genetic area that determines a person’s autoimmune capabilities, and is located on chromosome 6. The closer the match, the more successful the stem cell treatment will be.
If none of the family members prove to be a suitable match, then the doctor will check the national stem cell donor registry to see if there is a possible match there. Each country has its own national registry. Individuals wishing to become a donor should contact a local blood bank or the registry. The registry will need to catalog the donor’s HLA characteristics, and will require some tests to be performed.
HSCs are found in large quantities in umbilical cord blood. Stem cell banks preserve umbilical cord blood for a patient, in case the patient requires some form of stem cell treatment in the future. HSCs from cord blood can also be donated for research purposes. Researchers are also studying embryonic stem cells.
Embryonic stem cells (ES cells) are gathered when an embryo is a blastocyst. The blastocyst stage occurs four or five days after an egg has been fertilized, when the embryo is made up of 50 to 150 cells. The embryo must be destroyed for the cells to be harvested. For the purposes of stem cell treatment applications, ES cells are highly desirable because of their pluripotency, or ability to become any cell within the body.
Parkinson’s disease is a degenerative disease that causes the slow destruction of the nerve cells that produce the neurotransmitter dopamine within the brain. Researchers hope to find a way to encourage stem cells to become nerve cells, and to produce dopamine. Other brain disorders, like Alzheimer’s and Huntington’s diseases, multiple sclerosis, and spinal cord injuries can be treated in a similar manner.