The politics of human embryonic stem cells have proven to be a wedge issue in the last two elections, and many on the left have felt that the political stonewalling by Bush (restricting the number of ES cell lines, hiring hacks like Leon Kass to head the Presidential Council on Bioethics etc.) has been preventing potentially life-saving cures from being developed. A new paper just released this week by the journal
Nature (
here is a lay article and my
GiveUp Blog Post) may allow us to put this divisive issue to rest in the coming election. The findings of these researchers is simple. They were able to purify multipotent (maybe even totipotent) stem cells (cells capable of differentiating or turning into any stem cell type) from the testes of adult mice.
Now, this might not sound too exciting, but it is. More below the fold
First, the scientific gobbledegook. Skip to the conclusion if you don't want to hear exactly what they did.
Kaomei Guan et al. of the Georg-August-University of Göttingen Germany developed a fairly simple technique of creating stem cell lines resembling embryonic stem cell lines in nearly every way by harvesting testicles of mice, subjecting them to enzymatic digestion, and culturing in mouse stem cell medium (a magical combination of cow serum, LIF or leukemia inhibitory factor, and common cell medium). These cells, dubbed multipotent adult germline stem cells (maGSCs), then passed several critical tests indicating that they truly are stem cells capable of serving as a replacement for classic embryonic stem cells (ESC).
First, they implanted the cells into immune-deficient mice (also called nude mice) and the cells formed teratomas, a tumor consisting of all three embryonic lineages of cells. This is consistent with what happens when one implants ESC into nude mice.
Second, they differentiated the cells in vitro into "embryoid bodies" and ran a bunch of molecular tests showing they were capable of becoming many different cell types.
Finally, and most impressively, they injected the cells into mouse embryos, and the cells contributed to various tissues in the adult mice, and the genotype of the donated cells was transmissable to subsequent generations of mice.
So, what does all this mean? This means that these researchers are able to make cells from adult tissue that are equivalent, or nearly equivalent, to the ES cells that politicians have been fighting about for the last 8 years since James Thompson first isolated human ES cells from embryos discarded from IVF. I can not stress enough how important it is that these cells were harvested from adult tissues, and that they aren't just another form of adult stem cells which have been proven to be of limited utility. This means the cells are truly powerful stem cells, and they can be harvested in such a way that no embryos are destroyed, and they will match the donor genetically and immunologically.
Now, the three limitations and problems as they currently exist (as I see it), and why I'm optimistic that these problems are easily surmountable.
- The cells were purified from mouse, not human tissue. I have no doubt that this result will soon be replicated using donated tissue from humans or cadaverous donations. Mice and humans aren't too different in their development or genetics, and it is doubtful these multipotent stem cells exist only in the testes of this one mammal.
- The cells can only be purified from males. However, in March of 2004 J Johnson et al. published an article in Nature indicating germline stem cells exist and replicate even in the adult mammalian ovary. This was a finding that overturned decades of scientific dogma that females developed all their eggs before they were even born and suggests similar cells could be harvested from females. Further, even if cells can only be purified from males, banks of lines representing every possible combination of histocompatibility profile could be generated to match any potential recipient, or the cells could be engineered to be immunologically neutral in the recipient.
- This result needs to be replicated and expanded as the success rate isn't 100%. However, this is what science is best at, I'm sure that improvements could be made on the technique opening up the possibility that ES-like cells can be tailor-made for any human being on the planet.
Yes, I am possibly over-optimistic, however, this result is extremely exciting and I think at the very least may represent the death of the partisan issue of stem cell science. As this research is verified and expanded, it will allow us to bypass the problem of ES cell research requiring the destruction of embryos, and is even more powerful than existing stem cell techniques because the cells can be made to match the genetic profile of the donor without any further engineering like somatic cell nuclear transfer (aka cloning).
So, let us join together and celebrate! Science has found a way to bypass a nasty partisan dispute and kill a wedge issue that riled-up the religious right. Lets hope we see a paper on harvesting these cells from humans within the next few months (quite likely since the field is hot), and in the next election this will be one less issue hurting Democrats among the religious right. We are on the way towards ES Cell research being uninhibited by the current (and pointless) ethical morass, and as an ES cell researcher, I can tell you, the potential of this science is incredible. Incredible, not just for "cures," but for the advancement of human knowledge, I don't think there is an equivalent field of biologic investigation today. But then, I might be biased.
Finally, let us congratulate our German friends at the Georg-August-University of Göttingen for a paper that may end up sending them to Stockholm one day. This is truly a fantastic result that will have broad implications for the future of the biological sciences (if it pans out like I think it will). You heard it here first, Nobel Prize-worthy research being reported about at your very own Daily Kos.