Possible alternative to ES cells found in placenta

Scientists at the University of Pittsburgh, US, report that they have discovered that amniotic epithelial (AE) cells, found in the human placenta, have properties similar to those of embryonic stem cells (ES cells). Like ES cells, the AE cells can develop into a number of different tissues.

The team, led by Professor Stephen Strom and Professor Yoshio Miki, from the University of Pittsburgh Medical School's Department of Pathology, reported their findings online in the journal Stem Cells Express. Their work will also be published in a forthcoming edition of the journal Stem Cells. They show that AE cells isolated from full-term human placentas show surface markers normally present on ES cells. They also believe that, because AE cells develop before gastrulation, the process where the majority of embryonic cells divide into three 'classes' of cells which then develop into all other types of tissue, that they retain the ability to become any type of tissue.

Amniotic epithelial cells develop by eight days after fertilisation and are found in the thin membrane, known as the amniotic sac, that surrounds a fetus during pregnancy. They can be derived from the placenta after childbirth and so, say the scientists, could be a less controversial source of cells than ES cells, which necessitate the destruction of an embryo to obtain. 'We think it would be easier to get these to the clinic than embryonic stem cells', said Professor Strom. However, AE cells cannot 'live forever' as ES cells can, so any treatments based on them would depend on regularly harvesting cells from placentas.

Despite this limitation, the findings of the research group have been welcomed. Alan Russell, director of Pittsburgh's McGowan Institute for Regenerative Medicine, said that the discovery 'adds another piece to the puzzle that will help patients in future'.

The University of Pittsburgh has licensed the patent rights to a local biotechnology country called Stemnion, which plans to develop treatments for cirrhosis and diabetes using AE cells.