We saw it coming. We created stem cells from testis tissue and published it earlier this year and I mentioned previously that it should be possible to do the opposite and create spermfrom stem cells. Well, as announced yesterday from a research group in Britain, that possibility is closer to becoming a reality. Sperm created in a Petri dish. Artificial sperm.
Published yesterday in the journal Stem Cells and Development, this is being hailed by the press as “breakthrough” research. Now call me cautious, or call me a stem cell biologist, but I get suspicious when that term is used to describe medical research. More on that later. The technique, discovered by a team of biologists at the University of Newcastle in England and led by Dr. Karim Nayernia, purports to have created actual moving sperm from human embryonic stem cells. Not in a testicle, but in a laboratory dish. This group has some amount of “street cred” as they had previously published a paper in which mouse embryonic stem cells were used to produce in a dish. In fact, these sperm were injected into mouse eggs, formed mouse embryos and baby mice. However, a close look at the small print reveals the mouse pups all had “growth abnormalities” and died after birth.
Now back to being Mr. Cautious. If you look closely at the figures and video in the human paper, you might not be convinced that these are actual sperm. Pictures are a little too fuzzy. Kind of UFO-like. Could they really be neurons instead of sperm? Also, the sperm neither look nor move quite like what we would expect with normal sperm. Finally, some of the “reporter” genes that are used to classify the genetic origin of the cells are not working all that perfectly. Why didn’t the researchers provide more convincing evidence of the universally recognized elements of a sperm including the acrosome, midpiece with mitochondria and characteristic axonemal structure? Oh, and where are the controls?
There is no doubt that Dr Nayernia will face scrutiny for this work, as he has before. And this is all good. Because if the scientific world believes that it is true, then this is an amazing feat of science with enormous potential. For such acceptance to occur, a confirmatory study by another group will likely be necessary. Maybe ours, as we are investigating the same concept but in a radically different and much more feasible way—by trying to create an entire artificial testicle instead.
There are other meaty issues surrounding this research. Is it safe? Is it practical? Remember how inefficient it was to clone Dolly the lamb? Inefficiency runs rampant in any reproductive process. As an example, say that you discovered that humans can reproduce through sex and tried to license the process. With a 20% efficiency rate, you would probably be denied the license. On the other hand, if it is really true, this work has demonstrated the enormous potential of embryonic stem cells, as making a sperm is about as complex a process of cellular transformation that you will find in the body. Making bone, cartilage or heart cells should be much easier. Will it ever get to the point in which a healthy child might be conceived in this way? If that happens, then I might start thinking more about the real role of man in mankind. But not sooner. After all, if men become redundant in the reproductive process, who will replace men’s uncanny knack for opening jars?