Amniotic Fluid Yields Alternatives To Embryonic Stem Cells

Research findings raise the possibility stem cells derived from donated amniotic fluid could be stored and used for therapies and in research, providing a viable alternative to the limited embryonic stem cells currently available.

Researchers used stem cells from amniotic fluid donated by mothers undergoing amniocentesis for other purposes during the first trimester of pregnancy. The cells were grown on a gelatinous protein mixture in the lab and reprogrammed into a more primitive state by adding a drug called valproic acid to the culture medium.

Extensive tests found that these reprogrammed cells have characteristics very similar to embryonic stem cells.

“Amniotic fluid stem cells are intermediate between embryonic stem cells and adult stem cells. They have some potential to develop into different cell types but they are not pluripotent," said Dr Pascale Guillot, Department of Surgery and Cancer at Imperial College London. "We’ve shown that they can revert to being pluripotent just by adding a chemical reagent that modifies the configuration of the DNA so that genes that are expressed in the embryo get switched back on."

Even after growing in culture for some time, the reprogrammed cells were able to develop into functioning cells of many different types, including liver, bone and nerve cells. They also maintained their pluripotency even after being frozen and rethawed.

Amniotic fluid surrounds and nourishes the fetus in the womb. It can be extracted through the mother’s abdomen using a needle in a process called amniocentesis, which is sometimes used to test for genetic diseases. The fluid contains stem cells that come from the fetus. These cells have a more limited capacity to develop into different cell types than stem cells in the embryo.

Alternatives to embryonic stem cells are keenly sought because of ethical concerns and limited availability of donor embryos. Previous research has shown that it is possible to make adult cells become pluripotent by introducing extra genes into the cells, often using viruses. However, the efficiency of the reprogramming is very low and there is a risk of problems such as tumours caused by disrupting the DNA. The new study is the first to induce pluripotency in human cells without using foreign genetic material. The pluripotent cells derived from amniotic fluid also showed some traits associated with embryonic stem cells that have not been found in induced pluripotent stem cells from other sources.

Adapted from the Imperial College London announcement.