Researchers at the Institute of Regenerative Medicine at Wake Forest University in Salem, N.C. have discovered a type of cell that floats freely in the amniotic fluid of pregnant women and has many of the traits of embryonic stem cells, suggesting a potentially ethical source of pluripotent cells – cells that scientists believe can grow into any other human cell and thus regenerate tissue such as brain or muscle and potentially treat degenerative diseases including Alzheimer’s, heart disease and stroke.
Dr. Anthony Atala, the lead researcher, says amniotic fluid-derived cells “show great pluripotentiality.” The cells are “shed” by the unborn child during pregnancy and were found to be easier to maintain in laboratory dishes than embryonic stem cells, making them both preferable as a source of stem cells and ethical, because harvesting them does not require the destruction of the human embryo.
Medically speaking, they initially appear superior to ESCs because thus far, they have not developed cancerous tumours. In recent months, there have been numerous reports that stem cells derived from embryos have developed into cancerous tumours. But the stem cells collected by Atala’s team did not age and after two years living in the lab, still did not display any tumour development.
The Washington Post reported that when taken from amniotic fluid, they could most easily be applied to treat babies with birth defects because the cells would effectively be the baby’s own, reducing the risk of rejection. But researchers – including Dr. Atala – were quick to dismiss the idea that cells harvested from amniotic fluid would replace the need for embryonic stem cells. And U.S. Congressional Democrats voted to fund embryonic stem cell research the day after the study was released in the journal Nature Biotechnology.
The Washington Post reported that the discovery added “credence to an emerging consensus among experts that the popular distinction between embryonic and ‘adult’ stem cells – isolated from bone marrow and other organs – is artificial.” That is, adult or somatic stem cells have the same properties as ESCs for treatment.
The only serious ethical complaint concerns one specific method of gathering the fluid. Currently, amniotic fluid is retrieved during routine prenatal testing that utilizes amniocentesis. The procedure, which requires puncturing the uterus with a needle to collect the fluid (usually to test for genetic anomalies), has a one in 200 chance of resulting in miscarriage. Pro-lifers oppose such tests because of the risk to the life of the unborn baby, as well as the usual course of action when such tests determine that a child has a genetic abnormality such as Down syndrome. Approximately 80 per cent of the time, such diagnoses end in abortion.
But amniotic fluid can also be collected when a mother’s water breaks – and from the placenta that is expelled after birth, which is also a rich source of stem cells.
If researchers limited themselves to retrieving cells ethically at the time of birth, and not during pregnancy, amniotic fluid would provide an ethical and promising source of stem cells.