Overcoming Infertility: Fertile Mouse Eggs Produced From Stem Cells

Scientists have created eggs of mouse from stem cells to induce pregnancy and produce offspring.

They hope the study will help in finding out new ways to help infertile couples to conceive. It could possibly shed light on how eggs develop.

In the past, mouse pups using sperm from the stem cells have been created, but in the new study, a team of researchers led by Mitinori Saitou of Kyoto University have created eggs that were then used to grow offspring.

For their study, experts used embryonic stem (ES) cells taken from embryos and induced pluripotent stem (iPS) cells that were made using a cell from an adult and reprogrammed it to act like stem cells. When the researchers cultured both the stem cells in a blend of proteins, they produced germ cells, which are precursors to the sperms or eggs.

The egg precursor cells were blended with ovarian cells of the female mice to form reconstituted ovaries and then inserted in the ovaries of living mice.  After four weeks, the cells were developed into eggs or oocytes. They were then fertilized through the process of in vitro fertilization (IVF) and implanted into surrogate mothers. The pups that were born after a period of gestation were healthy and fertile, according to a report in Science.

"This is a significant achievement that I believe will have a sustained and long-lasting impact on the field of reproductive cell biology and genetics," Science quoted Amander Clark, a stem cell biologist at University of California, Los Angeles, as saying.

According to the researchers, with further study in the field they may be able to entice the entire oocyte development process in a lab dish.

Although fertility experts have considered the new research as a remarkable feat, they suggested that more careful study needs to be done before tackling such methods in humans.

"What is remarkable about this work is the fact that although the process is still quite inefficient, the offspring appeared healthy and are themselves fertile as adults. This is a great step forward, but I would urge caution as this is a laboratory study and we are still quite a long way from clinical trials taking place in humans," Guardian quoted Allan Pacey, a fertility expert at the University of Sheffield and chair of the British Fertility Society, as saying.