Open AccessConcise Review: Human‐Animal Neurological Chimeras: Humanized Animals or Human Cells in an Animal?
Author(s) -
Crane Andrew T.,
Voth Joseph P.,
Shen Francis X.,
Low Walter C.
Publication year - 2019
Publication title -
stem cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.159
H-Index - 229
eISSN - 1549-4918
pISSN - 1066-5099
DOI - 10.1002/stem.2971
Subject(s) - biology , blastocyst , chimera (genetics) , transplantation , human animal , complementation , stem cell , neuroscience , animal studies , embryonic stem cell , regenerative medicine , embryo , immunology , microbiology and biotechnology , genetics , phenotype , medicine , embryogenesis , gene , domestication , endocrinology
Blastocyst complementation is an emerging methodology in which human stem cells are transferred into genetically engineered preimplantation animal embryos eventually giving rise to fully developed human tissues and organs within the animal host for use in regenerative medicine. The ethical issues surrounding this method have caused the National Institutes of Health to issue a moratorium on funding for blastocyst complementation citing the potential for human cells to substantially contribute to the brain of the chimeric animal. To address this concern, we performed an in‐depth review of the neural transplantation literature to determine how the integration of human cells into the nonhuman neural circuitry has altered the behavior of the host. Despite reports of widespread integration of human cell transplants, our review of 150 transplantation studies found no evidence suggestive of humanization of the animal host, and we thus conclude that, at present, concerns over humanization should not prevent research on blastocyst complementation to continue. We suggest proceeding in a controlled and transparent manner, however, and include recommendations for future research with careful consideration for how human cells may contribute to the animal host nervous system. Stem Cells 2019;37:444–452