Articles appeared today in ‘Nature’ and ‘Cell Stem Cell’ reporting the creation of generations of mice using reprogrammed skin tissue from adult mice by two different teams of Chinese researchers (*). There were abnormalities in the first generation of offspring but these seem to have disappeared in subsequent generations.
The novelty of this process, which has already been achieved using embryonic stem cells, is that this time the starter cells did not involve the use and destruction of embryos.
The cells derived, known as induced pluripotent stem cells (iPSCs), can be obtained relatively easily from adult tissue sources, thereby avoiding the ethical controversies surrounding the use of embryos. These new studies confirm the principle that such cells have the same versatility as embryonic stem cells.
Until now there have been big questions surrounding the full extent of the potency of iPSCs, and these new mouse studies demonstrate that they are indeed as capable as embryonic stem cells of developing into any required tissue type; they are
as pluripotent as those derived from embryos.
For many researchers IPSCs are viewed as the supreme stem cell and CORE certainly acclaims proof of principle of their versatility, demonstrating qualities which clearly parallel those of embryonic stem cells.
Our enthusiasm, however, remains strictly within the parameters of animal studies and the basic principles involved.
We would be delighted if these mice studies eventually lead to human cures using adult-derived iPSCs, but that remains a far-off El Dorado, and we are naturally concerned as to how the passage from animal to human studies (and eventual therapies) might occur.
As it stands, none of this current research on mice could be replicated ethically in human studies, as it would involve the experimental destruction of many human embryos, unethical genetic manipulation in the process, high risks of abnormality and so on.
We should wait and see how these animal studies develop, while celebrating the fact that a useful proof of principle has been established, namely that pluripotent stem cells can be obtained from adult mammalian tissue without the destruction of embryos.