Stem cell research takes another big step

Using stem cells made from skin, a Japanese team has created healthy eggs that, once fertilised, grow into normal baby mice.

These babies later had their own babies, the BBC reported.

The team at Kyoto University used stem cells from two sources: those collected from an embryo and skin-like cells, which were reprogrammed, into becoming stem cells.

The first step was to turn the stem cells into early versions of eggs.

A “reconstituted ovary” was then built by surrounding the early eggs with other types of supporting cells that are normally found in an ovary. This was transplanted into female mice. Surrounding the eggs in this environment helped them to mature.
IVF techniques were used to collect the eggs, fertilise them with sperm from a male mouse and implant the fertilised egg into a surrogate mother.

“They develop to be healthy and fertile offspring,” Dr Katsuhiko Hayashi, from Kyoto University, told the BBC.

Those babies then had babies of their own, whose “grandmother” was a cell in a laboratory dish.

If the same methods could be used in people then, it could help infertile couples have children and even allow women to overcome the menopause. But experts say many scientific and ethical hurdles must be overcome before the technique could be adapted for people.

“I must say that it is impossible to adapt immediately this system to human stem cells, due to a number of not only scientific reasons, but also ethical reasons,” Dr Hayashi said.
He said that the level of understanding of human egg development was still too limited. There would also be questions about the long-term consequences on the health of any resulting child.

Their work was reported in the journal Science.