What’s the News: Researchers at Kyoto University in Japan have created fully functioning sperm from mouse embryonic stem cells

. The sperm cells were able to fertilize mouse eggs in vitro, and when the scientists implanted the embryos into surrogate mothers, the mice gave birth to healthy offspring. The research, published in the journal Cell

, may someday help treat infertility in humans. What’s the Context:

How the Heck:

The researchers first created epiblast-like cells from a cocktail containing embryonic stem cells and several growth factors and proteins, which control cell proliferation, differentiation, and other activities. Then, using their method devised a couple years ago, they turned those epiblast cells into primordial germ cells.

The team injected the germ cells into the testes of sterile mice. When the researchers later removed the mice’s testes, they found that the germ cells had matured into normal-looking sperm. So, they used the sperm to fertilize mice eggs in vitro, and implanted the eggs into several female mice. The mice later gave birth to 65 healthy pups, which then had babies of their own.

The Future Holds:

There is still a long way to go before the work can be translated to people—the main hurdle will be figuring out how to make human sperm cells from induced pluripotent stem cells, which are often taken from adult skin cells and other tissue. The researchers were able to do this in their mouse study (and some mouse pups were born), but the process was a lot less successful than when they used embryonic stem cells.

The researchers also want to figure out how to transform the embryonic stem cells into fully functioning eggs, and how to develop sperm without using mouse testes.

[via ScienceNOW

]

Image courtesy of Gilberto Santa Rosa / Wikimedia Commons