“New” Stem Cells Could End Embryo Controversy
February 12, 2007
By: Beth Walsh for Body1
Scientists may have found a source of stem cells that could put the controversy about this emerging medical advance to rest. Stem cells in amniotic fluid and placental tissue apparently have all the characteristics of embryonic stem cells, but can be harvested without harming the developing fetus.| Take Action | Stem Cells, Applied
Umbilical cord blood currently is the best way to collect stem cells.
Stem cells can help treat 45 different medical conditions, according to scientists.
Right now, bone marrow donations are the most common source of stem cells. About 30,000 individuals each year are diagnosed with conditions that could be treated with a bone marrow transplant. About 25 percent have a relative who is an appropriate tissue match and about 50 percent can find a suitable donor within four months.
Ounce for ounce, there are 10 times as many blood-producing cells in umbilical cord blood than in bone marrow. So, a smaller number of cord blood cells are needed for a successful transplantation. |
Anthony Atala, MD, director of Wake Forest University School of Medicine’s Institute of Regenerative Medicine, said his team has been working for seven years to determine whether cells from amniotic fluid are truly stem cells. Atala knew that if so, they could be used to produce a range of cell types with the potential to treat and perhaps cure numerous medical conditions. Although the scientists have been able to produce brain, liver and bone cells, they don’t know how many other different cell types might result from amniotic fluid cells. And, preliminary tests in patients are still several years in the future.
"Our hope is that these cells will provide a valuable resource for tissue repair and for engineered organs as well," said Atala. The report was published in Nature Biotechnology, on the heels of the November announcement by Swiss researcher Simon Hoerstrup that he could produce heart cells from amniotic fluid stem cells that could be grown into replacement valves.
Human embryonic stem cells, which are created in the first days after conception, can develop into any of the more than 220 cell types that make up the human body. Researchers are hopeful that they can train these primordial cells to repair damaged organs in need of healthy cells.
That’s good news for the almost 100,000 patients in the United States currently awaiting organ transplants. Donated organs each year only accommodate about one quarter of what is needed and many transplants fail due to organ rejection.
Despite the potential benefits, many people oppose the destruction of embryos for moral and ethical reasons. The Bush administration has severely restricted federal funding for embryo work since 2001, leading many scientists to search for alternative stem cell sources.
The research team discovered that about one percent of amniotic and placental stem cells could renew themselves repeatedly, just like embryonic stem cells, and could also become different types of tissue. The cells have marker characteristics of both embryonic and adult stem cells, and the researchers think they may represent an intermediate stage between the two types. The scientists wrote that these cells are readily available since they can be harvested from placentas, which are usually discarded after delivery. Cells are also available from amniotic-fluid specimens obtained during amniocentesis, a procedure performed at around four months' gestation to determine whether a fetus has genetic abnormalities.
These findings also indicate that the newly-discovered stem cells can be grown in large quantities because they double every 36 hours. They do not require guidance from other cells to differentiate into different types of tissue and don't produce tumors, which can occur when other types of stem cells are used.
The team has postulated that a cell bank with 100,000 specimens of these stem cells could supply 99 percent of the U.S. population with a perfect genetic match for transplantation. It would not be difficult obtaining that many specimens, they wrote, because there are more than four million live births each year in the United States alone.
The findings follow Atala’s success last spring in rebuilding bladders for seven young patients using live tissue grown in the lab. So far, the bladders have been functional for about six years.
Last updated: 12-Feb-07
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