The adult stem cell has been collected to treat leukemia, lymphoma and inherited blood disorders. Most recently, it’s believed stem cell therapies will benefit patients with diabetes and kidney cancer. While widespread human treatment using stem cells is still nearly a decade away, scientists are rigorously studying these cells for answers to some of life’s greatest mysteries: How do unspecified cells find their purpose? How do they know when to begin replicating and when to stop? Can we manipulate these cells inside the body or use transplanted cells outside the body to produce treatments? Will the body accept or reject these cells?
To be considered an embryonic stem cell, a young cell must be located in the inner mass of the blastocyst. By contrast, the adult stem cell is not characterized by its origin. To be considered stem cells adult variety, the cell must have the ability to differentiate and must be able to self-renew for the lifetime of its host. Scientists are always discovering new locations of adult stem cells, which have grown from the spinal cord and the bone marrow to include the brain, the blood vessels, the hair follicle, skeletal muscle, fat, the skin’s epithelia, the digestive system, the cornea, the retina, the peripheral blood, the teeth, the liver and the pancreas.
One of the most exciting adult stem cell discoveries occurred in 2008 when researchers at the Salk Institute for Biological Studies in La Jolla, California coaxed mouse brain stemcells to differentiate into support cells and function with the surrounding neuronal network. When pampered in a Petri dish, scientists found that they could encourage oligodendrocyte cells to form the fatty myelin sheath that speeds up the transfer of electrical signals along the axons. They could also stimulate cellular growth in the hippocampus; the brain’s center for memories and learning. Scientists hope this research can provide a breakthrough in the treatment of multiple sclerosis, Alzheimer’s, stroke and epilepsy.
The most studied type of adult stem cell is called a “hematopoietic stem cell,” which is derived from bone marrow. Using transplants, scientists have restored immune and blood components using stem cells. Scientists have identified stem cells in the hippocampus region of the brain whose function is currently unknown and are looking at ways to induce proliferation or differentiation in these seemingly dormant cells. Muscle, blood and fat stem cells may be able to transform into other cell types under certain conditions, which will fuel many studies in the years to come.