Stem Cells Without Damaging Embryos?

Stem Cells Without Damaging Embryos?

Last fall the biotech company ACT (Advanced Cell Technology) published research showing that it was possible to remove one cell from a developing mouse embryo and use it to originate a line of embryonic stem cells. (See blog posts from 10/17/05 and 10/18/05 for more info and links.) Now ACT had done this with human cells. Unsurprisingly, this is being hailed by some as a way to create embryonic stem cells without destroying embryos.

Before I get into the science of it, I have one crucial question: if the embryos are allowed to develop, who is going to take care of the resulting child? If the embryos are destroyed as they are now, then there’s no difference—so for this to be a major change in the ethics debate, the embryo has to fully gestate to infancy. The ideal scenario is that the new cells are extracted from embryos already destined for implantation via IVF; the parents get their baby, the scientists get their cells, everyone’s happy-- but extremely strict ethical guidelines and standards will need to be followed so that the parents are not pressured to allow this research to be done, and the issue of compensation will have to be thoroughly explored. The situations that could develop without these are terrifying: Are researchers going to have to hook up with adoption agencies? Who is going to donate her womb, and will she be paid? It seems to me far more unethical to cause an embryo to develop without having a parent waiting for it than it does to destroy a blastocyst. While I would like to believe the situation will always be aboveboard, there have to be fundamental protections in place.

OK, cautionary note aside, here’s what some of the media are saying about this technique. The BBC summarizes the technique nicely: “Using spare human IVF embryos, the researchers removed single cells from them, employing the same procedure used for pre-implantation genetic diagnosis (PGD), a technique that has been used in IVF so cells can be removed from the embryo and tested for genetic disorders.” In other words, the extraction is not a new technology; it is the successful creation of ESCs from the extracted cells that is the news. The researchers used 16 embryos and were successful in creating 2 lines. A thorough article in the San Jose Mercury News expands on the technique: the PGD testing—which has its own ethical issues—involves removing a cell and allowing it to divide. One of the resultant cells is then tested for genetic defects and mutations. The other resultant cell would be the one that could be used in research. An AP story in the Houston Chronicle is also instructive as to possible consequences of and objections to this technology, and gives a decent scientific grounding.

Issues that are being raised are the quality of the stem cell lines obtained—obviously this is not known yet, but it will have to be established before scientists see these as a reasonable alternative. There’s the issue as to whether the genetic testing can cause any damage to the embryo/child—no defects have been observed thus far in 1000 cases of the testing—but it’s still disrupting natural development, and the effects, if any, over a life-time are not known. There is also the question of whether the separated cell itself has viability; if it does, then we’re back at square 1 of the debate. And then there’s the legal issue—would these cells be exempt from the federal funding restrictions or still bound by them because they are derived from an embryo?

In other words, just because this can be done does not mean it is a solution to the embryo-destruction question, and it is problematic in other ways too. Certainly this seems like something that has potential, but don’t count on it to become the new scientific method for ESC research any time soon.