MGH's Tilly morphs human ovarian stem cells into eggs

This may not be news about embryonic stem cells, but it could end up being just as controversial. Researchers at Massachusetts General Hospital and elsewhere have figured out how to harvest stem cells from a woman's ovaries and encourage them to morph into functional eggs, using human cells in a lab dish and separately, with mice.

The Wall Street Journal offered a thoughtful account of the research and its implications in its Feb. 26 edition, and further details are published in the journal Nature Medicine. Bloomberg, The New York Times and many others followed-up with fairly compelling write-ups.

MGH's Dr. Jonathan Tilly, a reproductive biologist, built on his previous research suggesting that female mammals carried stem cells in their ovaries that could serve as a tool to produce eggs. Chinese scientists a few years ago built on this further by successfully isolating these stem cells from mice, culturing them in the lab, and generating apparently viable eggs after implanting the cells in mouse ovaries. For his latest work, Tilly and his group built on what the Chinese did, but in humans; they successfully isolated stem cells from the ovary cortex, cultured them in the lab, and developed eggs that appeared normal both physically and genetically.

Mice came in handy for a variation on this, in which scientists injected human ovarian stem cells into a small piece of ovarian tissue before grafting it under the mice's skins. Within two weeks, a number of immature eggs grew, glowing green based on a fluorescent marker the scientists used to tag the ovarian stem cells before the experiment.

Here's the thing: As the WSJ notes, this is extremely early research. The discovery has enormous promise to treat infertile couples. It would also be far less invasive to harvest a piece of ovarian tissue with the appropriate stem cells, rather than harvesting and storing eggs for stem cell use. The article also points out that the freezing and thawing process could cause less damage in stem cells than in eggs, because eggs carry more water.

But the research also presents profound ethical and health risks. What if the stem-cell-derived egg, for example, ends up horribly mutated? Would this process even be workable in fertility clinics depending on all the unstable mutations stem cells could create? If successful, would this make the process of giving birth to a child even more of a business proposition? And even if they use the process to test creating human embryos (as the story points out, this worked in mice), should they?

The WSJ reminds us that there are plenty of legal and ethical issues in the U.S. that could block human embryo creation for experiments. One possible out--U.K. researchers can do this, but must destroy such embryos after about two weeks. Regardless, there is a business angle here, already. The WSJ article adds that Tilly and colleagues have founded a company--OvaScience--to handle Tilly's team's "patent-protected findings."

- here's the WSJ story (sub. req.)
- check out the Bloomberg story
- consider The Associated Press/Los Angeles Times coverage
- read the NYT piece
- this is the journal abstract