Male infertility may soon be a subject in the archives of Biology!
According to new research released this week, Japanese scientists have reinstated fertility in sterile mice using laboratory-made sperm developed from embryonic cells. This novel development may pave the way for researching and treating infertility in people. For instance, skin cells of men may be reprogrammed to act like sperm producing units.
For decades, researchers have made several unsuccessful and controversial attempts to create sperm and eggs in a dish. Although in 2003 scores of scientists demonstrated the possibility of transforming mouse embryonic stem cells into both sperm and eggs, pregnancy could not be established.
While in 2006 another team of scientists used lan-grown sperm to create six mice, the animals were wiped out early by genetic abnormalities.
Yet again in 2009, Newcastle University researchers made news for reporting the test tube creation of human sperm, but weeks later their paper was withdrawn on accounts of plagiarism.
Now, researchers spiked mouse embryonic stem cells with growth factors and other chemicals, which control activities like cell proliferation and differentiation. In a lab dish, these additions effectively turned embryonic cells into epiblast-like cells, which are deposited in developing organs early during embryogenesis, and remain in several organs into adulthood.
Subsequently, researchers persuaded epiblast-like cells to transform into primordial germ cells by replicating the signaling process from the 2009 experiment. When the testes of 7-day-old sterile mice, in which natural sperm production was absent, were transplanted with these primitive germ cells, they produced normal-looking sperm. This was a breakthrough development and a monumental achievement!
A total of 214 embryos, each comprising two cells, were created from lab-grown sperm made to fertilize with eggs in a dish. The embryos thus created were transplanted into several female mice resulting in the delivery of 65 healthy male and female pups.
Research team leader, Dr. Saitou, stated: “The mouse babies are just fine and they’ve had normal, fertile babies of their own. The pregnancy rate achieved in the mice was comparable to what’s typically seen using naturally produced sperm and artificial insemination.”
Although it may not be feasible to replicate this very process in humans, it may be possible to reprogram mature male cells into an embryonic-like state, and further persuade them to grow into healthy sperm in a dish.
And this is exactly what the Japanese scientists did! Lab-grown sperm were obtained from reprogrammed mouse cells, following which eggs were fertilized with those sperm to produce babies in the mice.
Even though one of the most thrilling advances in biology is the capability to reprogram cells into an embryonic-like state, this technique is still unpredictable and unreliable as it often necessitates the exploitation of viruses that can induce tumors. Needless to say, Kyoto scientists noticed premature deaths, few from tumors, in at least 20% of the baby mice created through reprogramming.
Director of the stem-cell transplantation program at Children’s Hospital Boston, George Daley, commented: “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. It would be a monumental achievement since there’s currently no method for restoring female fertility.”