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Hastings Center News

New Project: Could Human Cells “Humanize” Research Animals?

And what does “humanize” even mean? Those are among the questions being explored in a new Hastings Center project, funded by the National Institutes of Health, on the ethical oversight of research with human-animal chimeras, laboratory animals that contain human cells.

With recent scientific advances, scientists are better equipped than ever to insert human cells into animals for research purposes. Many people hope that human-animal chimera research will yield enormous benefits, including more accurate models of human neurological and other diseases, inexpensive sources of human eggs and embryos for research, and sources of tissues and organs suitable for transplantation into humans.

But there are ethical concerns, including whether inserting large amounts of human neurons and other cells in the brains of nonhuman animals will somehow “humanize” them. What does “humanization” mean, and how is it measured or detected? When is it and when is it not ethically problematic? Does the creation of human-animal chimeras raise animal welfare concerns?

The project aims to understand what is motivating ethical concerns and to find a reasonable path forward that can be applied in research oversight. “Providing conceptual clarity about these concerns is essential for trustworthy oversight of the rapidly changing science of human-animal chimera research,” says Hastings Center research scholar Karen J. Maschke, one of the lead investigators.

Other project leaders are Josephine Johnston, The Hastings Center’s director of research and Insoo Hyun of Case Western University. Hastings research scholar Carolyn P. Neuhaus and president Mildred Z. Solomon are co-investigators.