On the topic of science and saving lives . . .

Amniotic fluids bring stem cell boost
Stem cells can now be harvested from amniotic fluids, researchers show

Scientists say they have discovered a new and less controversial source of powerful stem cells in the amniotic fluid that surrounds a developing fetus.

Researchers at North Carolina's Wake Forest University and Harvard Medical School in Boston report that these stem cells behave much like those from human embryos, but no embryo is destroyed in the process of harvesting them.

These cells seem to multiply at the same quick pace as embryonic stem cells, and could also be coaxed to become a variety of different tissues -- including bone, muscle, fat, brain and liver.

"These cells are yet another choice for a source of stem cells," said Anthony Atala, senior author of the report released yesterday in an advanced online publication of the journal Nature Biotechnology.

"They're neither embryonic stem cells, nor adult stem cells . . . they're somewhere in the middle."

Dr. Atala said these amniotic-fluid stem cells, dubbed "AFS cells," would make it "much easier to get material for research purposes and also for clinical applications."

Amniotic fluid is known to be rich with the cells that a fetus sheds and doctors routinely collect it from pregnant women to screen a fetus for genetic diseases. Amniotic-fluid samples that would otherwise be discarded could therefore be a "readily available" source of stem cells, the researchers say.

They also suspect there could be a plentiful supply since AFS cells were also found in placentas after birth -- and there are millions of births in North America each year, Dr. Atala noted.

With such a broad spectrum of potential donors, Dr. Atala suggested these cells could not only be stored to meet the future medical needs of the baby, but also banked for general use.

But both Dr. Atala and other stem-cell experts agree that much remains to be learned about these cells.

"I don't think it's going to replace embryonic stem cell research at this point. Lots has to be done to see a clear picture of these cells," said Andras Nagy, a senior scientist at the Samuel Lunenfeld Research Institute at Toronto's Mount Sinai Hospital.

"We have to find out, what are the limitations of these cells? What are these cells? We have to be very careful not to get overexcited."

Dr. Nagy, who developed the first two human embryonic stem cell lines in Canada, said it may be that different diseases could be treated with stem cells derived from different sources. Still, he said, he doubted these new amniotic cells "will be able to do as many things as embryonic stem cells."

Stem cells from human embryos are prized as the potential keys to regenerative medicine. They alone have the proven power to multiply indefinitely and become any cell type in the human body. Scientists suspect they could be used to grow patients' replacement tissues and parts, such as new nerve cells to treat spinal-cord injuries or new arteries for heart patients.

But since a human embryo is usually destroyed to harvest these stem cells, those who believe life begins at conception are morally opposed to research in the area.

Federally funded researchers in the United States, for example, are banned from most research on embryonic stem cells. In Canada, embryonic stem cell research can only be conducted under tight restrictions on donated embryos considered surplus at fertility clinics.

Scientists have as a result been investigating alternate stem cell sources in adult tissues and in the umbilical cords of newborns. But the quantity of stem cells in an umbilical cord is too small to help a child once they grow into their teenage years, Dr. Atala noted. Stem cells from adult tissues, meanwhile, are difficult to grow in large quantities and do not have the versatility of embryonic stem cells to become different tissues.

Dr. Atala and his colleagues first isolated a stem cell from amniotic fluid seven years ago. However, "it took us seven years to get this work out there," he said, because proving it is a true stem cell has been a laborious process.

Mick Bhatia, director of the Stem Cell and Cancer Research Institute at McMaster University in Hamilton, called the report "a very interesting biological finding."

"The ethical component seems clear, there's no destruction of anything here," he said. But Dr. Bhatia noted that a whole new set of scrutiny will come to bear on how researchers might obtain amniotic fluid samples and how consent is collected from prospective parents.

"The other big issue with this kind of work, is how often can you pull it off? Often these kinds of things can be hard to reproduce," he said.

Dr. Bhatia said, for example, that the paper does not offer details about how many amniotic fluid samples had to be tested to find those with a good supply of stem cells. Still, he said: "I might want to give it a shot."

In the published report, the researchers write that stem cells made up about 1 per cent of the cells found in the amniotic fluid of 19 different donors.

Dr. Atala noted during a teleconference last Friday that these stem cells were even easier to grow than embryonic stem cells because they required no special nutrients, so-called "feeders." Still, they doubled in quantity every 36 hours, just as embryonic stem cells would do. Researchers then went on to double each line 250 times.

The cells were coaxed to become six different cell types in culture dishes in the lab. But the scientists also tried to demonstrate their function.

They showed, for example, that human neural cells grown from these stem cells were able to repopulate the brain of immune-deficient mice and survive for two months. They also showed that bone cells grown from these stem cells actually led to bone formation on artificial scaffolding inside mice.

Still, Dr. Atala stressed, "This is very early work. It is still several years before we would try this in a patient."

Original article posted here.