Jan. 9, 2007 -- Stem cells found in discarded amniotic fluid may hold the key to new treatments for disease and injury.
The newly discovered amniotic fluid stem cells may not be "pluripotent," or capable of forming every type of adult tissue. But they come very close. When grown in the right environment, they can become fat cells, bone cells, brain cells, muscle cells, blood vessel cells, or liver cells.
And when transplanted into special mice, human amniotic fluid stem cells placed in the brain become functional brain cells. After being placed on scaffolds and properly nourished in the test tube, stem cells implanted into mice form bone.
The findings come from the lab of Anthony Atala, MD, director of the Institute for Regenerative Medicine at Wake Forest University in Winston-Salem, N.C.
"Amniotic fluid stem cells hold potential for a variety of therapeutic applications," Atala and colleagues suggest.
The amniotic fluid stem cells may, in fact, have an advantage over embryonic stem cells. The embryonic cells have a tendency to grow wildly and form tumors. The amniotic fluid stem cells do not form tumors.
Another obvious advantage is that the stem cells come from the amniotic fluid obtained from a previously planned amniocentesis. This fluid would normally be discarded.
During amniocentesis, doctors take a small amount of amniotic fluid from the womb by inserting a fine needle into the uterus through the abdomen, under ultrasound guidance. It is done to check for some types of birth defects, such as Down syndrome.
Though the stem cells do seem to come from the developing fetus -- cells from the fluid surrounding male children carry a male Y chromosome -- the cells are harvested from the amniotic fluid and not from the fetus itself. Similar cells can be found in the placenta after full-term pregnancies.
The findings appear in the advance online publication of the journal Nature Biotechnology.
The new findings, while exciting, do not eliminate the need for embryonic stem cells, cautions a news release from the Genetics Policy Institute (GPI), a nonprofit organization that advocates for stem cell research.
"There is only one 'card carrying' pluripotent human embryonic stem cell," GPI director Bernard Siegel, JD, says in the news release. "Most scientists believe that different types of stem cells will eventually be needed to treat different diseases."