Stem cells' clock turned back

U.S. researchers reprogram adult cells to behave like embryonic stem cells

Researchers at Harvard University have reprogrammed adult skin and bone cells, teaching them how to revert to embryonic stem cells with all the potential for therapeutic regeneration those progenitor cells hold.

Though the process is far from ready for prime time, experts suggested Monday it points to a day when cells from an individual could be used to grow new tissues that would be an identical genetic match to the donor, avoiding the rejection problems associated with transplantation.

It also would provide researchers with an easy and accessible source of embryonic stem cells, a source untainted by the controversy that surrounds stem cell generation.

Embryonic stem cells can "differentiate" or mature into any type of tissue, and the reprogrammed cells appeared to have that skill. The researchers enticed them to mature into nerve cells, hair follicles, muscle cells and cells from the gut.

However, the fused cells carried a full set of genes from both the adult and the embryonic stem cells.