Stem cell-based regenerative medicine has the potential to help treat not only humans with injuries or illness, but also veterinary patients such as dogs and horses.
Is it also possible that stem cell technology could prevent extinction of endangered species?
A recent paper suggests this may be the case.
The paper in question by a team lead by one of my favorite stem cell scientists, Jeanne Loring, was published online on Sept. 4 in Nature Methods and is Ben-Nun, et al. You can read it here. The work was done in cooperation with the San Diego Zoo.
Loring’s team made induced pluripotent stem cells (iPSCs) from two endangered species: a primate called “the drill”, andrillus leucophaeus, and the white rhino, Ceratotherium simum cottoni.
Despite efforts to the contrary, both species are in trouble and could very well become extinct in the future. However, if these two species disappear from the wild or even earlier if they decline rapidly but are not yet extinct, it is possible that iPSC derived earlier from the animals could be used to clone them, produce offspring, and reintroduce them into the wild.
In fact, in theory it should be possible to do this for all endangered species, forming in essence a cell bank, like an insurance policy against extinction.
However, life is not so simple and despite the power of iPSC technology there are some possible hitches in this idea of saving endangered species. While cloning based on iPSC has worked in mice, it is unclear how well this may work in other species. It could also take production of a lot of unhealthy individuals of any given species to produce one healthy, fertile member based on this method. The authors also used what has become the standard in the iPSC field: retroviral transduction. When producing iPSC in this way, this method results in integration of the iPSC-inducing viruses, leaving open the possibility that they could be re-activated in cloned animals down the road and could cause cancer or other problems.
There is also the risk of introducing say a white rhino cloned using iPSC technology back into the wild because that white rhino would not only have the viral integrations, but also even if in the future scientists succeed (as I suspect they will) in making rhino iPSCs in a non-genetic manner, iPSC contain mutations and are not genetically identical to the parental cells from which they were derived. As a result there could be unpredictable consequences in a population as a whole from breeding with such a cloned animal. However, if the alternative is extinction, such theoretical risks may well be worth taking.
I think this paper is quite interesting and opens the door to saving species that because of human actions are headed toward potential extinction. While there are some things to iron out as discussed above, I think this is an exciting advance. Of course an alternative to this approach would be somatic cell nuclear transfer (SCNT)-based approaches to making ES cell lines from endangered species, but that may turn out to be less practical than this iPSC-based approach.