Jan. 9, 2007 -- Stem cells found in discarded amniotic fluid may hold thekey 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. Butthey come very close. When grown in the right environment, they can become fatcells, bone cells, brain cells, muscle cells, blood vessel cells, or livercells.
And when transplanted into special mice, human amniotic fluid stem cellsplaced in the brain become functional brain cells. After being placed onscaffolds and properly nourished in the test tube, stem cells implanted intomice form bone.
The findings come from the lab of Anthony Atala, MD, director of theInstitute for Regenerative Medicine at Wake Forest University in Winston-Salem,N.C.
"Amniotic fluid stem cells hold potential for a variety of therapeuticapplications," Atala and colleagues suggest.
The amniotic fluid stem cells may, in fact, have an advantage over embryonicstem 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 amnioticfluid obtained from a previously planned amniocentesis. This fluid wouldnormally be discarded.
During amniocentesis, doctors take a small amount of amniotic fluid from thewomb by inserting a fine needle into the uterus through the abdomen, underultrasound guidance. It is done to check for some types of birth defects, suchas Down syndrome.
Though the stem cells do seem to come from the developing fetus -- cellsfrom the fluid surrounding male children carry a male Y chromosome -- the cellsare harvested from the amniotic fluid and not from the fetus itself. Similarcells can be found in the placenta after full-term pregnancies.
The findings appear in the advance online publication of the journalNature Biotechnology.
The new findings, while exciting, do not eliminate the need for embryonicstem cells, cautions a news release from the Genetics Policy Institute (GPI), anonprofit organization that advocates for stem cell research.
"There is only one 'card carrying' pluripotent human embryonic stemcell," GPI director Bernard Siegel, JD, says in the news release. "Mostscientists believe that different types of stem cells will eventually be neededto treat different diseases."