Fertility scientists in Japan created sperm-producing germ cells in a laboratory and implanted them into infertile mice and after the treatment, these mice were able to produce healthy offspring.
The discovery, which has been described by experts as “hugely exciting”, could help thousands of infertile men become parents if the process proves similarly successful in humans.
Researchers at Kyoto University were able to use stem cells from mouse embryos to create primordial germ cells, which drive the production of sperm in men. When implanted to the testicles of infertile mice, the cells then produced normal-looking sperm.
The research team was led by Dr. Katsuhiko Hayashi, and they injected the sperm into mouse eggs and transplanted them into female mice, which were then able to give birth to healthy pups.
According to a study in the Cell journal, the babies were capable of reproducing naturally once they grew up. Previous experimental attempts to create sperm from embryonic stem cells have been quite unsuccessful and in most cases, they even led to unhealthy offspring which soon died.
Fertility expert Dr. Allan Pacey, senior lecturer in andrology at the University of Sheffield, said, “This is quite a step forward in developing a process by which sperm could be made for infertile men, perhaps by taking as a starting point a cell from their skin or from something like bone marrow. Clearly more work needs to be done to refine this process, but it’s hugely exciting.”
Pacey also said, “The philosophy of the law is to stop that kind of thing happening. But in this case you’re not technically creating sperm, so it might be that you can sidestep this regulation. It all depends on definition.”
George Daley, director of the stem-cell transplantation program at Children’s Hospital Boston, who read the Cell paper but wasn’t involved in the study has also stated, “It’s a brilliant set of experiments. They restored fertility in the mice. It lays the groundwork for major insights into sperm development and fertility.”