For the past two days new research has been grabbing media headlines. A study published in the journal Nature Biotechnology reports remarkable success in deriving stem cells from amniotic fluid. The cells have shown great promise in the lab for being potentially as versatile and useful as human embryonic stem cells for eventual therapies. Dr. A. Atala and his team took samples from amniocentesis specimens (from both human and rodent sources) and were able to grow lines of amniotic fluid-derived stem (AFS) cells. They describe the procedure as robust and fairly straight-forward. These AFS cell lines grew reasonably quickly (they divided every 36 hours) and for many generations without developing any propensity for chromosomal abnormalities or tumors. The research team also demonstrated that the cells have the ability to produce multiple, different cell types, at least in tissue culture. They produced liver, bone and nerve cells.

For one of these cell types (nerve cells), they also performed transplantation experiments in mice and showed that the cells performed some of their expected functions. If this work is verified and replicated by other labs, it represents a significant step forward towards the identification of a non-embryonic pluripotent source of transplantable cells. In particular, the ability of AFS cells to be expanded extensively and the fact that they can be replicated as described in the paper, are very attractive properties.

However, it is important to remember that the cells described here resemble another potential cell source described in research that is now several years old. So-called multipotent adult progenitor cells (MAPC) were described then as holding out very similar properties and potential. Unfortunately, many of the initial claims regarding the properties of MAPC have not been replicated. In particular, their therapeutic utility has not been validated. It is therefore best to be cautious at this point in time with regard to any hopes that might be raised by this new research. A single report of this kind does not yet represent definitive proof that AFS cells can do everything that embryonic stem cells could purportedly do. However, we should hope that with time AFS cells will fare better in terms of scientific replication than have other sources of non-embryonic pluripotent cells.

Markus Grompe, M.D. is a Senior Fellow of the Westchester Institute and Director of the Oregon Stem Cell Center. He is also a member of the board of directors of the International Society for Stem Cell Research.

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