Fertile mouse sperm created from Stem Cells

Scientists in the United States have coaxed stem cells from mice to change into immature sperm that can fertilise eggs to develop into embryos.

Scientists in the United States have coaxed stem cells from mice to change into immature sperm that can fertilise eggs to develop into embryos.The achievement could pave the way for new ways of treating male infertility. Researchers at the Children’s Hospital Boston/Harvard Medical School and the Whitehead Institute for Biomedical Research said on Wednesday they plan to transfer the embryos into female mice to see if they develop normally. “What we would really like to know is, will these cells… that we formed in the dish, actually sustain the development of an embryo,” said Dr George Daley, a stem cell biologist, in an interview. “If that is true and it is normal, then it opens up possibilities for novel forms of reproductive biology.” Stem cells are master cells able to grow into all cell and tissues in the body and hold the promise of treating medical conditions ranging from heart disease and infertility to Parkinson’s disease. But their use is controversial because although they are found in adult tissue, the most flexible stem cells come from early embryos. Dr Daley and his colleagues cultured embryonic mouse stem cells in the laboratory and then isolated the germ cells – rare stem cells destined to become sperm or eggs. After the germ cells developed into immature sperm, the researchers injected them into female mice and created embryos. Dr Daley is now trying to determine whether the same technique would work with human embryonic stem cells. “Our first indications are that we are going to see the same phenomenon but it is going to take us a little while longer to work out the detail,” he said. “It could easily translate into new ways of understanding male infertility.” Genetic instructionsThe research, which is reported online by the science journal Nature, will also allow the scientists to study a unique set of genetic instructions called imprints, which control growth and the activity of genes inherited from the father and the mother. Cells have imprints for life but they are erased in embryonic germ cells. In certain cancers, imprints that slow down cell division are lost, so cancer can grow uncontrollably. “We hope to use these embryonic germ cells to study how the erasure process is initiated normally, and how it is disrupted in some cancers,” Dr Niels Geijsen, of Massachusetts General Hospital and the lead author of the report, said in a statement. The embryonic germ cells may also help scientists understand how erasure occurs and how stem cells are programmed to specialise and create different tissue and body parts. “This may teach us how we can reverse the process and reprogramme adult cells back to their embryonic state,” Dr Daley added.(Source: Reuters Health, ABC Health News, Dec 2003)