A form of primordial slime could hold the answer to preserving the fertility of women who have cancer — and even help preserve critically endangered mammals such as the Siberian tiger and Mexican wolf.
The ”slime”, called alginate, is extracted from algae, and is being used by a team of fertility scientists from Northwestern University in Illinois in the United States.
”We have shown that alginate supports the development of female eggs for embryonic development,” says Teresa Woodruff, the professor of neurobiology and physiology who led the study.
Obstetrician and gynaecologist Richard Kennedy, a member of the development team, says one of the benefits is that it avoids the need to stimulate the ovaries with drugs that might be harmful if the patient has breast cancer.
Woodruff and colleagues aimed to develop a way to allow immature eggs still within their follicle (the structures in the ovary where the egg develops) to grow outside the body, with the aim of preserving viable eggs. Culturing whole follicles in this way has previously proved very difficult. But, Woodruff points out, the work also has implications for threatened species: presently, only the male germline can be stored.
The team has shown that follicles grown in alginate keep the connections between follicle and egg, leading to eggs that can be fertilised more easily, at least in mice.
Significantly, the new technique could let immature human eggs from young women be frozen and stored, as sperm already can be. That would enable women being treated for cancer to keep their eggs in an egg bank, to be used later.
Kennedy explains: ”For women who require treatment that will jeopardise their fertility, such as chemotherapy, egg freezing has been recommended as a treatment, but to date has been very unsuccessful.”
Woodruff’s team has been researching the field for nearly 20 years. Until now, scientists have put eggs into a plastic-based material as part of an almost two-dimensional process. But scientists needed a material that allows the follicle to grow, move and change in shape as the egg grows just as it does in the human body; that is, they needed a substance that allowed them to work in three dimensions.
Kennedy says their technique uses a three-dimensional template for the development of the follicle — which makes sense as the follicle is a three-dimensional structure. ”Previously, follicles have only been grown in vitro on a two-dimensional culture system, and hence have been much less successful.”
The researchers also needed to find a material that was not bioactive — that is, had no effect on living tissue. Woodruff says materials such as collagen — often used for breast implants — are not viable because they are bioactive.
Professor Lonnie Shea, another lead scientist in the research, said: ”Alginate is also useful because it keeps cells together and it allows for the follicle to be taken out at the end of the process.
”We can also use another substance to degrade the alginate without any apparent harm to the follicle,” he added.
Other applications could prove promising for boys who have cancer. Although it is possible to preserve sperm, it has not been possible for boys before the onset of puberty. Stem cells could be used in these cases, though this is a long-term goal.
The technology could also be used in the long term for nerve regeneration to treat paralysis and perhaps transplantation of certain cells for diabetes treatment.
However, conservationists and zoologists are hoping this research can be applied in their field sooner, to allow them to preserve the lineage of critically endangered species — especially when the numbers of a species are so low, as in the case of the Mexican wolf and Siberian tiger, that urgent action is necessary to save them from extinction. — Â