Man-Made Sperm Reverses Infertility, Says Study
Scientists have discovered a way to use stem cells to create healthy sperm, a breakthrough that could be the key to solving male infertility in humans.
According to the study published today in the journal Cell, a group of Japanese scientists created the sperm from embryonic stem cells and then implanted them into infertile mice. These mice were then able to go on and father normal, healthy and fertile pups of their own.
"All I can say is wow! It is a breakthrough," says Orly Lacham-Kaplan, a reproductive biologist at Monash University in Australia.
For years scientists have been looking to find a way to create viable sperm in order to solve infertility issues in men. Although this study was performed exclusively on mice, experts say that this is a huge step forward in understanding how sperm develop and function and could be applicable to future human research.
The researchers wrote in their study that simply understanding how stem cells transform naturally into an egg or a sperm – and then being able to replicate it in a lab setting is “one of the most fundamental challenges in biology”.
Up until now scientists have only been able to create the very early stages of the sperm cell and keep them alive and regenerating in a petri dish for long periods of time. But, nobody could figure out how to turn these cells into viable sperm that could produce offspring.
In a new approach, the Japanese researchers took the early form of the cells, grew them in a special mixture of growth factors and proteins before then injecting them into the testes of the mice. There, the cells flourished and grew into healthy, normal sperm. Once the sperm were created the scientists removed the sperm and used them to fertilize mice eggs in an in vitro procedure before transferring the resulting embryos into female mice for gestation.
Although the breakthrough is significant, the researchers say that the ability for this type of technology to be applied in humans is quite a ways off. Embryonic stems cell research in humans is controversial and requires ethical hurdles which will be a challenge to overcome. Furthermore, the researchers say that ideally they would like to learn how to create the sperm completely in a lab setting, without having to inject the cells into the male testes for maturation.
Dr. Norbert Gleicher, founder of the Center for Human Reproduction and expert in low semen treatment, also points out that the need for such a treatment in humans may be a bit limited. Men who are diagnosed with azoospermia (low or absent sperm) can undergo a procedure called TESE, which retrieves sperm directly from the testicles in a surgical procedure. However, in some cases even with these procedures no sperm can be detected.
“Creating fresh sperm, therefore, would be useful in only about 15% of males with azoospermia, where we do not find even one sperm during TESE or testicular biopsy,” said Gleicher in an email. “In such males, the process is promising. However, we are, likely, still many years away from trying this in humans.”