WHILE THE DEMOCRATIC-CONTROLLED House voted 253-174 to expand federal funding for embryonic stem-cell research, it fell far short of the 290 votes needed to override a virtually guaranteed presidential veto. A tragedy for victims of everything from Alzheimer's to warts? Not at all. Each year there are stunning breakthroughs with adult stem cells, and 2007 has already brought its first.
Adult stem cells cure and treat more 70 diseases and are involved in almost 1,300 human clinical trials. Scientists also keep discovering that adult stem cells are capable of creating a wider variety of mature cells. Perhaps the most promising of these was announced in the January issue of Nature Biotechnology.
Anthony Atala, director of the Institute for Regenerative Medicine at Wake Forest University School of Medicine, reported that stem cells in the amniotic fluid that fills the sac surrounding the fetus may be just as versatile as embryonic stem cells. At the same time they maintain all the advantages that have made adult stem cells such a success.
This has caused great consternation on the part of those seeking increased taxpayer embryonic stem cell funds. The reason is that there are currently no practical applications for this type of cell. There hasn't even been a single clinical trial involving them. Researchers admit we won't have approved embryonic stem cell treatments for at least 10 years.
One advantage of embryonic stem cells has been that most types of adult stem cells cannot be multiplied outside of the body for very
long, while embryonic ones may replicate in the lab indefinitely. But Atala's new amniotic stem cells grow as fast outside the body as embryonic stem cells (doubling every 36 hours), and he's now been growing the same cell line for two years, with no indication of slowing.
That leaves embryonic stem cells with only one possible advantage--potential. Embryonic stem cells can be "differentiated" into all three "germ layers," or subtypes of cell. That means they should be able to be made into all of the 220 types of cells in humans. For a long while, adult stem cells were believed to be only capable of differentiation to a limited number of mature cells, depending on the type of adult stem cell with which you start. For example, a marrow cell could become any number of types of marrow or blood cells, but it couldn't become a muscle cell. That's a different germ layer.
Yet it's been virtually a state secret that for over five years researchers, beginning with a team headed by physician Catherine Verfaillie of the University of Minnesota Stem Cell Institute, have been reporting numerous types of adult stem cells (she used those from marrow) that in the lab could form mature cells from three germ layers. Experiments around the world have clearly shown that adult stem cells from one germ layer can be converted into those of another in a living human, such as those that turned marrow cells into heart muscle and blood vessels in live humans.
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