In a scientific breakthrough, researchers report that they've grown mouse sperm from testicular tissue in the laboratory, a development that could advance the field of infertility in human males. Although still proven in mice, “this is a small but important step in understanding how sperm are formed, which may, in time, lead to us being able to grow human sperm in the laboratory,” said Dr. Allan Pacey, senior lecturer in andrology at the University of Sheffield in England, who is familiar with the study results.
The authors of the study write that sperm production is highly complex. Sperm previously created in a laboratory from mammal tissue didn't fulfill its purpose, Pacey said, noting offspring produced from it soon died. This study published in the March 24 issue of the journal Nature, involved experiments where researchers took tissue from the testes of baby mice and coaxed it into producing sperm cells. They then inseminated female mice, which had healthy babies. Seven of the mice were born after sperm heads were transferred into 23 eggs using a technique called round spermatid injection, and another five were born after 35 eggs were fertilised using intracytoplasmic sperm injection (Icsi), a common IVF procedure. Importantly, the scientists retrieved healthy sperm from tissue that was cultivated after being frozen for up to 25 days, suggesting that cold storage did not harm the cells.
Experts warn that the research would need confirmation by other studies in animals and humans before it could become feasible to grow human sperm in a laboratory. But the potential exists for the procedure to help some cases of male infertility. “It will be useful for diagnosis and treatment of infertility in future, for sure,” said study co-author Dr. Takehiko Ogawa, a urologist at Yokohama City University Graduate School of Medicine in Japan who led the study. “One of the problems I face, as a urologist, is that we do not have any effective ways to treat patients suffering from male infertility due to defective or insufficient sperm production…Most of these problems are for unknown reasons,” he explained. And the sperm-growing procedure shouldn't be expensive, Ogawa added.
This could especially be good news for males who have cancers before they can become fathers. “Years later, grown sperm in the laboratory could allow them to have children that were genetically theirs,” Pacey said. However, legal issues may arise regarding obtaining testicular tissue from kids who are not old enough to give consent, he added.
“It's really exciting,” said Mary Ann Handel, a reproductive genetics research scientist at Maine's Jackson Laboratory. “I really do think that he's really achieved a goal that a lot of people have tried over the years.” “It is a significant breakthrough,” added Martin Dym, a professor of biochemistry and molecular and cellular biology at Georgetown University. Dym was part of a team that tried, and failed, to accomplish in vitro growth of functional sperm ten years ago. “We did make sperm, but could not succeed in getting the sperm to make pups. The Japanese team has better sperm.”
Cancer risk elevated in families with male infertility