Scientists Grow Mouse Sperm Out of Embryonic Stem Cells

Scientists in Japan announced Friday they have grown healthy mouse sperm out of embryonic stem cells, opening up new possibilities for treating human infertility.

Reuters reported:

Scientists at Kyoto University removed stem cells from mouse embryos and managed to coax them into a type of precursor cell known to grow into either mouse eggs or sperm.

They then transplanted these cells into the testes of infertile male mice — which apparently went on to produce healthy sperm.

“The sperm were removed directly from the testes and fertilized with eggs (on laboratory dishes),” said lead author Mitinori Saitou, a professor at Kyoto University’s department of anatomy and cell biology.

“After insemination, we made two set of embryos and these were transferred into the uterus of the foster mother and they derived healthy mice (that went on to reproduce normally).”

The announcement is a major advance for regenerative medicine, which looks to use stem cells to multiply and grow different types of tissue to treat diseases, including cancer, diabetes and Parkinson's disease.

Saitou told the Wall Street Journal the team's success breaks new ground for fertility research, but "we have a long way to go before it can be applied to humans."

"Our work is still a purely scientific achievement using the mouse and the application of this work to human material involves a lot more work, time and ethical discussion," he told the Daily Mail.

Because the success in creating sperm only applies to male infertility, Saitou said his next goal is to use embryonic stem cells to create fully-functioning eggs, something that would be a major achievement as the first advancement in restoring female fertility.