Stem cell research is a developing technology that focuses on using undifferentiated cells therapeutically to treat human disease and injury. Stem cells are primitive or unspecialized cells that can assist in tissue repair and rejuvenation. When they divide, stem cells have the potential to become any type of cell needed, such as brain, blood or muscle cells.
Stem cells can be adult or embryonic. Embryonic stem cells are pluripotent, which means they can become any type of cell in the body. Adult stem cells are undifferentiated cells that can be induced to become other types of tissue cells, but may be less flexible than embryonic stem cells.
Once a stem cell line is established, it is essentially "immortal." Researchers can use this line indefinitely without harvesting additional stem cells.
Currently, only adult human stem cells are used to treat disease, such as bone marrow transplants for leukemia.
According to the National Institutes of Health, stem cell research has the potential to alleviate many human illnesses and conditions, including some birth defects and cancers, Parkinson's disease, amyotrophic lateral sclerosis, spinal cord injury, burns, heart disease, diabetes and arthritis.
The first human clinical trials using embryonic stem cell therapies began in January 2009. The California-based Geron Corporation received FDA clearance to being research trials with patients with complete spinal cord injuries.