by Carolyn Plunkett Neuhaus, Ph.D.

NIH is seeking public comment on a new policy regarding chimeras. From the Greek word for a fire-breathing animal with a lion’s head, a goat’s body, and a snake’s tail, “chimera” in this context means a non-human organism that has human components – such as human tissues or organs. Scientists create chimeras by inserting human cells (usually induced pluripotent cells) into a non-human animal embryo.

Chimeras allow scientists to study human tissue and organ development and human diseases without doing experiments on actual humans. For example, they could study the development of treatment of human liver diseases by growing human livers in pigs. One day, we may be able to grow livers and other organs in pigs for transplantation. Researchers will be better able to model and study human neurological diseases like Alzheimer’s or Parkinson’s in animals with human neurons and nervous systems. The creation of chimeras is an essential starting place for this line of research.
NIH temporarily banned funding of chimeras in September 2015. The funding ban did not make chimera creation illegal; it meant that no federal funds could go to research involving chimeras. Despite the NIH ban on chimera research, the California Institute for Regenerative Medicine, and other institutions, continued to review and fund research on chimeric rats and mice.

The NIH imposed the ban due to ethical concerns. These include welfare concerns over animals whose brains might contain human brain cells, husbandry concerns, and what might happen if chimeras reproduce. Additional concerns include confusion over species identification, and what that means for moral status. For example, is a pig with human neurons really a pig? Should we afford it the same moral consideration as the average pig?

The new NIH policy, made available for public comment on August 4^th, will lift the funding ban on research involving chimeras. But, to allay ethical concerns, it builds in a few safeguards.

First, it will continue a ban on the insertion of human cells into non-human primate embryos up through the end of the gastrulation stage. Scientists, however, will be able to introduce human cells into non-human primates later in the developmental process. Second, NIH will not fund research that involves breeding chimeras. Chimeras are not allowed to reproduce, even in controlled laboratory setting, when those labs receive federal funding.

Finally, NIH will create a Steering Committee that will review all federally funded chimera research and advise the NIH and its associate Institutes on chimera research. The Steering Committee does not replace typical channels of scientific and peer review at NIH.

The move to fund chimera research – with appropriate safeguards and oversight – is good. Research that NIH will fund will advance basic research on embryo development, organ development, disease progression, and other health-related concerns.
Yet one thing wrong with the proposed policy is that the Steering Committee is not required, at least not explicitly required in the draft, to have public representatives. The policy says it will be composed of “federal employees.” This raises the worry that public input and concerns over chimera research will not be adequately considered and addressed, and the public will not have a say in the direction of research.

We already have a model for public involvement in animal research. Institutional Animal Care and Use Committees (IACUCs) must have a non-scientist member and a non-affiliated member that represent the interests and concerns of the public. Rebecca Dresser says their role is to, “serve as reminders that animal research and education activities must be defensible to the broader society whose support is necessary to continue these activities . . . Once nonscientists become part of the committee, investigators and other committee members must explain and justify scientific practices using terms and concepts accessible to laypersons” (Dresser 1999).

They occupy a valuable and ethically important role on IACUCs, so why not have non-scientific and non-affiliated members of the Steering Committee for chimera research at NIH? Here we would have a committee whose task is to review and direct the use of chimeric animals across the institution, much like an IACUC. Like animal use more generally, the creation of chimeric animals should be defensible to the broader society. Having non-scientific and non-affiliated members of the Steering Committee for chimera research at NIH would go a long way toward earning public trust and support.

Finally, the idea of a human/animal chimera is confusing, and how chimeras are described typically misleading. Pigs with a human liver will not look or be human, even though they may be described as “humanized.” The NIH Steering Committee for chimera research should ensure that research agendas and funding opportunities are put into terms that the American public can understand, and explained in way that enhances their understanding rather than induces a collective “huh?” or “yuck!” Public representatives can help achieve that goal and make sure that it remains a priority.