March 23, 2011

expert reaction to Nature paper on in vitro production of functional sperm in mice

Scientists successfully produced functional sperm by culturing cells from the testes of newborn mice.

Dr Allan Pacey, Senior Lecturer in Andrology at the University of Sheffield, said:

“”This is a very interesting study. There have been several attempts to create or ‘grow’ animal sperm in the laboratory by various different approaches. However, none have been wholly successful and when the sperm have been used, the pups born have not been healthy and have soon died. In this study, the scientists have kept pieces of tissue from mouse testicles alive in the laboratory for several weeks and were able to grow sperm-like cells that had clear sperm-tails. Moreover, once these were injected into eggs, healthy pups were born that were themselves fertile in due course.

“To be able to ‘grow’ sperm in this way would be useful so that we could study the process of sperm production. Because sperm develop in the testicle, and we cannot yet replicate this in the laboratory, it is not totally clear how sperm are formed and why in some men it doesn’t work properly. This could help discover new drugs or treatments to stimulate infertile men to produce more or better sperm. It also may help preserve the fertility of some males.

“For most men who have gone through puberty, the best way to preserve their fertility is to bank sperm. That works very well, and we have been doing this since the 1950’s. But for men who don’t have any sperm to bank (perhaps because they are too ill before cancer treatment) or if they are too young (they haven’t started producing sperm yet), to be able to freeze some testicular tissue and years later grown sperm in the laboratory could allow them to have a children that were genetically theirs. However, to do this in the UK is currently illegal and of course we would have to make sure that this was perfectly safe. So there is still an awful lot of lab work to do.

“I think this study is a small but important step in understanding how sperm are formed which may, in time, lead to us being able to routinely grow human sperm in the laboratory. However, it is important to be cautious because sometimes species-specific differences in biology means that what works for one species does not work in another. Also, it is clearly important to make sure that any sperm produced are safe and give rise to healthy offspring when used, and that they in turn have healthy offspring ..etc .etc. We need to be cautious with this kind of work.”

‘In vitro production of functional sperm in cultured neonatal mouse testes’, Takuya Sato et al, published in Nature, Wednesday 23rd March 2011.