New Guidelines for Human/Animal Stem Cell Research

The National Institutes of Health (NIH) is considering updating its guidelines for stem cell research. The proposed new guidelines would allow human pluripotent stem cells to be inserted into non-human vertebrate embryos under certain conditions. Federal funding for such research has been prohibited since 2009 to give NIH time to study the issues carefully.

It seems clear that the NIH wishes to avoid the accidental (or on-purpose) production of human/animal chimeras; animals that are too close to human in their physical, mental, or emotional traits. To avoid this possibility, NIH plans to review carefully any experiments in which the human cells are introduced before the gastrula stage in the embryo - when the three germ cell layers begin to develop. A special restriction is that human cells may not be introduced into primates before the blastocyst stage. Proposals will be reviewed by a special steering committee comprised of scientists, ethicists, and even animal welfare specialists. The committee may consider such things as where the human cells are likely to end up in the animal, as well as how the human cells might affect the animal's physical and behavioral traits.

Why do this type of research at all? Scientists argue that the chimeras produced in this way (perhaps rodents with some human cells or tissue types) would be useful for understanding some human diseases, as well as for drug testing on animal models. Perhaps one day it might be possible to produce human organs suitable for transplant in animals. But that day is a long way off.

What do you think? You have until Sept. 6 to submit your comments NIH.