Bioethics Blogs

The lure of human-animal chimera research

Andrew Fenton and Letitia Meynell call for moral reflection on the primacy of capacities for determining the moral status of non-human animals used in human-animal chimera research.


Last week Nature and Cell published research that takes us closer to creating non-human animal hosts for growing human organs. According to their Nature article, Tomoyuki Yamaguchi and colleagues modified rats to grow mouse pancreata that were then used to successfully treat diabetic mice. According to their Cell article, Jun Wu and colleagues modified embryonic pigs and allowed them to develop long enough to confirm that human cells could be successfully integrated into their tissues and organs.

Both studies represent advances in what is known as chimera research. Chimeras are animals (human or otherwise) possessing cells containing a genetic identity distinct from their parents and sometimes from their own species. Human-animal chimera research is largely motivated by shortages in human organs available for transplant. The hope is that in the not too distant future, part-human chimeric animals will grow what are effectively human organs to make up for the shortfall.

Cardiac muscle cells. Photo Credit: David C. Zebrowski, Felix B. Engel

This research is receiving a good deal of media attention. Some scientists express cautious excitement about the breakthroughs while other scientists and ethicists express worries about the use of non-human animals in such invasive research and question its legitimacy.

Ethical confusion is understandable. The non-human animals typically used in this research – mice, rats, pigs and cows – don’t have a high moral status in our society.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.