What are some stem cell therapies that are currently available?
Routine use of stem cells in therapy has been limited to blood-forming stem cells (hematopoietic stem cells) derived from bone marrow, peripheral blood, or umbilical cord blood. Bone marrow transplantation is the most familiar form of stem cell therapy and the only instance of stem cell therapy in common use. It is used to treat cancers of the blood cells (leukemias) and other disorders of the blood and bone marrow. In bone marrow transplantation, the patient’s existing white blood cells and bone marrow are destroyed using chemotherapy and radiation therapy. Then, a sample of bone marrow (containing stem cells) from a healthy, immunologically matched donor is injected into the patient. The transplanted stem cells populate the recipient’s bone marrow and begin producing new, healthy blood cells. Umbilical cord blood stem cells and peripheral blood stem cells can also be used instead of bone marrow samples to repopulate the bone marrow in the process of bone marrow transplantation. In 20