Foetus-friendly Stem Cells
The practice of destroying an embryo to harvest its stem cells so they can be used to repair diseased tissues is highly controversial; some argue that it constitutes destroying life to preserve life and is unethical. But now Paolo de Coppi and his colleagues, from the Wake Forest Institute for Regenerative Medicine in Winston-Salem, US, may have discovered a more foetally-friendly form of stem cell, in the amniotic fluid that surrounds a developing baby. Writing in the journal Nature Biotechnology, the researchers describe how they have found a population of cells, dubbed AFS cells, which possess many of the same characteristics that make embryonic stem cells attractive but which can be harvested without harming the developing foetus. They make up about 1% of the cells which are naturally found floating in amniotic fluid, and they can be identified and collected using a stem cell specific marker called "c-kit". Once isolated the cells continue to divide in culture for long periods of time but without showing any signs of genetic ageing, and when injected into experimental animals they don't trigger cancers, which is a common problem with embryonic stem cells. Also, by exposing the AFS cells to a variety of chemical signals, the team were able to turn them into muscle, pancreas, liver, brain and even bone-forming cell types. The cells survived stably when they were injected into mice and the team were even able to make new bones by implanting a scaffolding coated with AFS cells. Over an 18 week period, CT scans of the implanted animals showed that the scaffold had been mineralised, but only when AFS cells were present. "Our hope is that the cells will provide a valuable resource for tissues repair and for engineered organs too", said project senior scientist Anthony Atala.