Amniotic Fluid New Source for Multi-Potent Stem Cells

By Maggie Fox, HealthDay News, January 7, 2007

A new source of stem cells has been discovered reported scientists Sunday afternoon. A readily available supply of these new cells, which are found in amniotic fluid, could solve the ethical problems that surround embryonic derived cells.

The amniotic stem cells are pluripotent, with the capacity to develop into many different types of cells including, nerve, liver, fat, blood vessel, muscle, and bone cells.

"These cells are easier to get, and from acceptable medical procedures [for example, amniocentesis] that are done on a routine basis," said study senior author Dr. Anthony, director of the Institute for Regenerative Medicine at Wake Forest University School of Medicine.

"This is another source of multi-potential cells," added Paul, director of the University of South Florida Center for Aging and Brain Repair, in Tampa. "Because the cells can be accessed either post-birth or through amniocentesis, it's possible that people could store those cells. If the cell lines that are created were available, then people could do some research on a non-embryonic source, which eliminates all the ethical and political issues."

The January 7th issue of Nature Biotechnology has reported on the discovery of the cells, which are known as amniotic fluid-derived stem (AFS) cells.

The hope is that treatments or even cures for conditions such as spinal injury, stroke, liver failure, diabetes, heart disease, and Alzheimer’s, could be developed with stem cells that have the potential to develop into many different cell types in the body.

But as of August 9th, 2001, when President Bush placed limits on federal funding for stem cells, the state of research in the U.S. has been severely hampered. Stem cell lines derived from embryos prior to that date are the only ones now eligible for federal funds.

Finding a new and less controversial source of stem cells was the goal for scientists from that point on.

Shed from the developing embryo, placenta and amniotic fluid contain a large number of stem cells. "These cells could be harvested, grown outside the body and used," Anthony said.

However, these cells were predestined to grow into a limited type of other cells or only one type of cell, which is unlike “true” stem cells.

"We wanted to see if there was a true stem cell population within this fluid, pluripotent stem cells which could give rise to multiple cell types," Anthony explained. Pluripotent cells are capable of differentiating into many different types of cells.

Anthony’s team found that 1 percent of the amniotic fluid cells were pluripotent after nearly seven years of research. The characteristics of these new found cells rest half way between adult stem cells and embryonic stem cells. Capable of doubling in number every 36 hours by self-renewal, they are like other stem cells. But they do not produce tumors, unlike other stem cells.

Anthony said that anytime from the beginning of pregnancy to just until after the baby is born, the stem cell could be harvested.

In experiments, the cells re-populated diseased areas of the brain in mice with degenerative brain disease. The AFS cells were differentiated into nerve cells prior to implantation. Further studies with mice revealed that it was possible to grow liver cells that could secrete urea as well as bone cells that could successfully grow into bony tissue.

Researchers did say that before any human benefit could be derived from these cells, more tests would be needed.

"It's a very nice paper, very good science," said Dr. Darwin, director of the Center for Gene Therapy at Tulane University Health Sciences Center in New Orleans. "But I can't quite put a circle around the potential of the cells. They may be useful for some kinds of therapy but I don't quite know where it's going to go."

According to Anthony, 99 percent of the U.S. population could be supplied with a perfect genetic match for transplantation with a bank of only 100,000 specimens.

However, his theory has a way to go given that human studies haven't even begun yet.

"We don't know what the extent of therapy will be with these cells," Anthony said. "Time will tell."