Stanford researchers implant lab-grown human cells into genetically altered mice

The short version

• Stanford researchers implanted lab-grown human cells into mice genetically engineered to lack parts of their brains, including the cerebral cortex.[Al Jazeera]
• The human tissue reportedly grew about five times larger within three months, connected to blood supply and filling over 90 percent of brain cavities.[Al Jazeera]
• The experiments were stopped when the human cells were six months old, before further neural connections or signs of consciousness appeared.[Al Jazeera]
• John Evans, a University of California, San Diego sociologist not involved in the study, said it does not in itself raise major ethical issues but suggests other animals could raise more serious concerns.[Al Jazeera]

Key facts

• Researchers at Stanford University implanted lab-grown human cells into mice genetically engineered to lack parts of their brains, including the cerebral cortex.[Al Jazeera]
• Each implanted unit was grown from healthy donors' stem cells and contains about 100,000 human cells.[Al Jazeera]
• Researchers attempted the transplants in 29 mice, and they worked in 25 of them.[Al Jazeera]
• Researchers removed about 14 million mouse neurons and added about 4 million human neurons.[Al Jazeera]
• Within three months, the human tissue was about five times larger, connected to blood supply, and filled more than 90 percent of the brain cavities.[Al Jazeera]
• The researchers stopped the experiments when the human nerve cells were six months old, before further neural connections or any signs of consciousness appeared.[Al Jazeera]

Sources

Outlet counts describe coverage, not independent confirmation. Reports may share a wire service or original source.

• ‘Alien-cortical’ mice: Can human brain cells grow inside animals?Al Jazeera