Stem Cell Research Races Toward the Clinic
"From multiple points of view it's extremely exciting when viewed from the bedside. When viewed from a basic science point of view of what we thought we knew about cell fates, cell commitment, and development, it's just as exciting," say Ira Black, MD, chairman of neuroscience at the Robert Wood Johnson Medical School in Piscataway, N.J.
In addition to providing investigators with new, potentially limitless sources of human stem cells, the discoveries promise to help stem-cell researchers steer their way around the roadblocks thrown in their paths by people who for religious or political reasons oppose the use of stem cells derived from human embryos.
There are, in fact, many different types of stem cells, representing various stages of cells taken from different parts of the body. Embryonic stem cells used in research are derived from embryos generated for the purpose of in vitro fertilization but never implanted. Although these embryos, more than 100,000 of which are currently in cold storage, are usually discarded, many anti-abortion rights activists are opposed to their use for scientific research, even when the ultimate goal is compassionate medical research.
In addition to embryonic stem cells, there are other types of stem cells that are derived from cells that have moved partway down the path to becoming a specific type of tissue, such as blood vessels, organs, or nerve cells.
As Black and colleagues show, they have been able to take stem cells from the bone marrow of adult rats and humans -- cells that are normally fated to grow into blood vessels and similar tissues -- and with a little manipulation in the laboratory convince them to turn into nerve cells instead. As if that trick weren't impressive enough, they've managed to do it in a matter of minutes or hours, rather than days or weeks as one might reasonably expect.
"There are a number of remarkable potential advantages," Black tells WebMD. "The cells grow remarkably quickly in culture, so that with a single bone marrow [collection] we can obtain a virtually limitless supply of cells. In addition, the accessibility certainly obviates the need to go into the brain ... [and] then obtain neural stem cells from deep within the cerebral hemisphere."