A new laboratory technique allows human embryonic stem cells to be grown and maintained without contamination by animal cells or products.The finding may help overcome a roadblock to safe stem cell research and treatment.Researchers at the University of California, San Diego, created controversy in January by noting that the animal-sourced “feeding layers” used to culture and maintain human stem cells in the lab could introduce potentially dangerous non-human molecules into transplanted stem cells.However, a new study -- also by UCSD researchers and published in the April issue of the journal Stem Cells -- demonstrates that laboratory culture media enriched by a human protein called activin A can maintain human embryonic stem cells in a continuous undifferentiated state, ready to be used for research. An “undifferentiated state” means stem cells have not yet started the process of development toward becoming specific human organs or tissue.
